May 2025, 日本機械学会, 2024年度バイオエンジニアリング部門業績賞　　　　　　　　　　　　　　　

2008, 日本機械学会賞（論文）　　　　　　　　　　　　　　　
Japan

2004, 2003年度日本機械学会バイオエンジニアリング部門第12回瀬口賞　　　　　　　　　　　　　　　
Japan

2004, 日本エム・イー学会第18回日本エム・イー学会秋季大会研究奨励賞　　　　　　　　　　　　　　　
Japan

2002, Outstanding Paper Award at the International Congress on Biological and Medical Engineering　　　　　　　　　　　　　　　

2002, Finalist for a Calgary Award at the IV World Congress of Biomechanics　　　　　　　　　　　　　　　

2002, 日本エム・イー学会平成13年度科学新聞賞・研究奨励賞・阪本研究刊行助成賞・阿部賞　　　　　　　　　　　　　　　
Japan

2001, Award for Best Poster in the Category Cell and Molecular Mechanics　　　　　　　　　　　　　　　
Japan

2000, Outstanding paper award　　　　　　　　　　　　　　　
Japan

2000, 日本機械学会賞（論文）　　　　　　　　　　　　　　　
Japan

Pre-alignment of fibroblasts induced by micropatterning and cyclic stretching techniques accelerates wound healing
Ryota Toyohara, Yanan Lan, Yu Chen, Takaya Yoriki, Toshiro Ohashi
Bio-Medical Materials and Engineering, 36, 3, 200, 206, SAGE Publications, 17 Jan. 2025, [Peer-reviewed], [Last author]
English, Scientific journal, Background

Wound healing proceeds through a complex collaborative process. It has been shown that during the intermediate phase of the wound healing process, fibroblasts migrate into wound area and contract to contribute to the closure of the wound area. Moreover, previous studies have shown that fibroblast alignment was observed on the mature stage of wound scar. These studies clearly indicate that fibroblasts play a critical role in wound healing process, however, the whole mechanism of wound healing remains still unclear.

Objective

Fibroblasts are pre-aligned to evaluate the effect of cell alignment on cell migration rate.

Methods

The cell alignment was accomplished by PDMS microstamping with fibronectin and application of cyclic stretching. Wound was created by physical scratching and then the wound closure rate was measured.

Results

The pre-aligned cells perpendicular to the direction of scratched wound exhibited significantly higher migration rate, compared to non-aligned control cells. Moreover, pre-aligned cells with thick actin filaments by cyclic stretching migrated faster than those with less development of actin filament structures by microstamping.

Conclusion

The wound closure can be accelerated by the adequate alignment of fibroblasts as well as the development of actin filament structures.

A Review of Fabrication and Applications of Confined Microchannels for Cell Migration Assay
Mazlee Bin Mazalan, Ryota Toyohara, Toshiro Ohashi
International Journal of Precision Engineering and Manufacturing, 25, 7, 1525, 1538, Springer Science and Business Media LLC, 27 May 2024, [Peer-reviewed], [Last author]
English, Scientific journal

A literature review of biomechanical studies on physiological and pathological sacroiliac joints: Articular surface structure, joint motion, dysfunction and treatments
Ryota Toyohara, Toshiro Ohashi
Clinical Biomechanics, 114, 106233, 106233, Elsevier BV, Apr. 2024, [Peer-reviewed], [Last author]
English, Scientific journal

In silico analysis on sacroiliac joint fixation during normal walking
Ryota TOYOHARA, Daisuke KUROSAWA, Niels HAMMER, Toshiro OHASHI
Journal of Biomechanical Science and Engineering, 19, 4, 24, 00036, Japan Society of Mechanical Engineers, 2024, [Peer-reviewed], [Last author]
English, Scientific journal

Experimental characterization of motion resistance of the sacroiliac joint.
Ryota Toyohara, Niels Hammer, Toshiro Ohashi
Bio-medical materials and engineering, 31 Jul. 2023, [Peer-reviewed], [Last author], [International Magazine]
English, Scientific journal, BACKGROUND: The human sacroiliac joint (SIJ) in vivo is exposed to compressive and shearing stress environment, given the joint lines are almost parallel to the direction of gravity. The SIJ supports efficient bipedal walking. Unexpected or unphysiological, repeated impacts are believed to cause joint misalignment and result in SIJ pain. In the anterior compartment of the SIJ being synovial, the articular surface presents fine irregularities, potentially restricting the motion of the joints. OBJECTIVE: To clarify how the SIJ articular surface affects the resistance of the motion under physiological loading. METHODS: SIJ surface models were created based on computed tomography data of three patients and subsequently 3D printed. Shear resistance was measured in four directions and three combined positions using a customized setup. In addition, repositionability of SIJs was investigated by unloading a shear force. RESULTS: Shear resistance of the SIJ was the highest in the inferior direction. It changed depending on the direction of the shear and the alignment position of the articular surface. CONCLUSION: SIJ articular surface morphology is likely designed to accommodate upright bipedal walking. Joint misalignment may in consequence increase the risk of subluxation.

Effect of width of microchannel device on behavior of collective cell migration
Mohamad Anis Bin RAMLAN, Ryota TOYOHARA, Toshiro OHASHI
Journal of Biomechanical Science and Engineering, 18, 4, 23, 00536, Japan Society of Mechanical Engineers, 2023, [Peer-reviewed], [Last author]
English, Scientific journal

Numerical analysis of the effects of padded pelvic belts as a treatment for sacroiliac joint dysfunction.
Ryota Toyohara, Takahiro Hiramukai, Daisuke Kurosawa, Niels Hammer, Toshiro Ohashi
Bio-medical materials and engineering, 08 Dec. 2022, [Peer-reviewed], [Last author], [International Magazine]
English, Scientific journal, BACKGROUND: Pain related to the sacroiliac joint (SIJ) accounts for low back pain in 15%-30% of patients. One of the most common treatment options is the use of pelvic belts. Various types of pelvic belts exist; however, the mechanisms underlying treatment and their effectiveness remain unclear to date. OBJECTIVE: To analyze stress distribution in the pelvis when a pelvic rubber belt or a padded pelvic belt is applied, to assess the effectiveness of treatment from a numerical biomechanical perspective. METHODS: The pressure distribution at the pelvic belts was measured using a device and subsequently modeled with the finite element method of a pelvis with soft tissues. The stress environment when wearing a pelvic belt in a double-leg stance was simulated. RESULTS: With the application of pelvic belts, the innominate bone rotated outward, which was termed an out-flare. This caused the SIJ to compress and cause reduction in sacrotuberous, sacrospinous, interosseous, and posterior sacroiliac ligament loading. Padded pelvic belts decreased the SIJ displacement to a greater extent than in pelvic rubber belts. CONCLUSION: Pelvic belts aid in compressing the SIJ and reduce its mobility.

A patient-cohort study of numerical analysis on sacroiliac joint stress distribution in pre- and post-operative hip dysplasia
Ryota Toyohara, Ayumi Kaneuji, Noriyuki Takano, Daisuke Kurosawa, Niels Hammer, Toshiro Ohashi
Scientific Reports, 12, 1, 14500, 14500, 25 Aug. 2022, [Peer-reviewed], [Last author], [International Magazine]
English, Scientific journal, In acetabular dysplasia, the cartilaginous roof on the acetabular side does not fully cover the femoral head, which may lead to abnormal stress distribution in both the femoral head and pelvis. These stress changes may have implications to the adjacent sacroiliac joint (SIJ). The SIJ has a minimal range of motion and is closely coupled to the adjacent spine and pelvis. In consequence, the SIJ may react sensitively to changes in stress distribution at the acetabulum, with hypermobility-induced pain. The purpose of this study was to investigate the stress distribution of the SIJ in acetabular dysplasia, and to gain insight into the cause and mechanisms of hypermobility-induced pain at the SIJ. Finite element models of pre- and postoperative pelves of four patients with acetabular dysplasia were created and analyzed in double leg standing positions. The preoperative models were relatively inflare, the sacral nutation movement, SIJ cartilage equivalent stress, and the load on the surrounding ligaments decreased with increased posterior acetabular coverage. Acetabular morphology was shown to affect the SIJ, and improvement of the posterior acetabular coverage may help normalize load transmission of the pelvis and thus improve the stress environment of the SIJ in acetabular dysplasia.

Reduction of Cardiac Fibrosis by Interference With YAP-Dependent Transactivation
Gloria Garoffolo, Manuel Casaburo, Francesco Amadeo, Massimo Salvi, Giacomo Bernava, Luca Piacentini, Isotta Chimenti, Germana Zaccagnini, Gesmi Milcovich, Estella Zuccolo, Marco Agrifoglio, Sara Ragazzini, Otgon Baasansuren, Claudia Cozzolino, Mattia Chiesa, Silvia Ferrari, Dario Carbonaro, Rosaria Santoro, Martina Manzoni, Loredana Casalis, Angela Raucci, Filippo Molinari, Lorenzo Menicanti, Francesca Pagano, Toshiro Ohashi, Fabio Martelli, Diana Massai, Gualtiero I. Colombo, Elisa Messina, Umberto Morbiducci, Maurizio Pesce
Circulation Research, 131, 3, 239, 257, Ovid Technologies (Wolters Kluwer Health), 22 Jul. 2022, [Peer-reviewed]
English, Scientific journal, Background:

Conversion of cardiac stromal cells into myofibroblasts is typically associated with hypoxia conditions, metabolic insults, and/or inflammation, all of which are predisposing factors to cardiac fibrosis and heart failure. We hypothesized that this conversion could be also mediated by response of these cells to mechanical cues through activation of the Hippo transcriptional pathway. The objective of the present study was to assess the role of cellular/nuclear straining forces acting in myofibroblast differentiation of cardiac stromal cells under the control of YAP (yes-associated protein) transcription factor and to validate this finding using a pharmacological agent that interferes with the interactions of the YAP/TAZ (transcriptional coactivator with PDZ-binding motif) complex with their cognate transcription factors TEADs (TEA domain transcription factors), under high-strain and profibrotic stimulation.

Methods:

We employed high content imaging, 2-dimensional/3-dimensional culture, atomic force microscopy mapping, and molecular methods to prove the role of cell/nuclear straining in YAP-dependent fibrotic programming in a mouse model of ischemia-dependent cardiac fibrosis and in human-derived primitive cardiac stromal cells. We also tested treatment of cells with Verteporfin, a drug known to prevent the association of the YAP/TAZ complex with their cognate transcription factors TEADs.

Results:

Our experiments suggested that pharmacologically targeting the YAP-dependent pathway overrides the profibrotic activation of cardiac stromal cells by mechanical cues in vitro, and that this occurs even in the presence of profibrotic signaling mediated by TGF-β1 (transforming growth factor beta-1). In vivo administration of Verteporfin in mice with permanent cardiac ischemia reduced significantly fibrosis and morphometric remodeling but did not improve cardiac performance.

Conclusions:

Our study indicates that preventing molecular translation of mechanical cues in cardiac stromal cells reduces the impact of cardiac maladaptive remodeling with a positive effect on fibrosis.

Identification of leader cells by filopodia in collective cell migration using computer vision
Mun Kit Lai, Baasansuren Otgon, Toshiro Ohashi
Bio-Medical Materials and Engineering, 1, 9, IOS Press, 19 Apr. 2022, [Peer-reviewed], [Last author]
English, Scientific journal, BACKGROUND: Imaging of cells and cellular organelles has been of great interest among researchers and medical staff because it can provide useful information on cell physiology and pathology. Many researches related to collective cell migration have been established and leader cells seem to be the ones that regulate the migration, however, the identification of leader cells is very time-consuming. OBJECTIVE: This study utilized computer vision with deep learning to segment cell shape and to identify leader cells through filopodia. METHODS: Healthy Madin–Darby Canine Kidney (MDCK) cells cultured in a Polydimethylsiloxane (PDMS) microchannel device allowed collective cell migration as well as the formation of leader cells. The cells were stained, and cell images were captured to train the computer using UNet++ together with their corresponding masks created using Photoshop for automated cell segmentation. Lastly, cell shape and filopodia were filtered out using Filopodyan and FiloQuant were detected. RESULTS: The segmentation of cell shape and the identification of filopodia were successful and produced accurate results in less than one second per image. CONCLUSIONS: The proposed approach of image analysis would be a great help in the field of cell science, engineering, and diagnosis.

Mechanical Properties of Isolated Primary Cilia Measured by Micro-Tensile Test and Atomic Force Microscopy　　　　　　　　　　　　　　　
Tien-Dung Do, Jimuro Katsuyoshi, Haonai Cai, Toshiro Ohashi
Frontiers in Bioengineeing and Biotechnology, 2021, [Peer-reviewed], [Last author]

Quantitative evaluation of the sacroiliac joint fixation in stress reduction on both sacroiliac joint cartilage and ligaments: a finite element analysis　　　　　　　　　　　　　　　
B. Venayre, Y. Koyama, D. Kurosawa, N. Hammer, U. Lingslebe, E. Murakami, H. Ozawa, T. Ohashi
Clinical Biomechanics, 85, 105350, 2021, [Peer-reviewed], [Last author]

Finite element analysis of load transition on sacroiliac joint during bipedal walking
R. Toyohara, D. Kurosawa, N. Hammer, M. Werner, K. Honda, Y. Sekiguchi, S. Izumi, E. Murakami, H. Ozawa, T. Ohashi
Scientific Reports, 10, 1, 13683, 13683, 2020, [Peer-reviewed], [Last author], [International Magazine]
English, Scientific journal, The sacroiliac joint (SIJ) is burdened with variant loads. However, no methods have allowed to measure objectively how the SIJ deforms during bipedal walking. In this study, in-vivo walking conditions were replicated in a kinematic model combining the finite element method with 3D walking analysis data divided into five phases in order to visualize the load transition on the SIJ and clarify the role of the SIJ. Both models with and without inclusion of the SIJ were investigated. In models with bilateral SIJs, the displacement differed greatly between the sacrum and both hip bones on the SIJ as the boundary. The movements of the sacrum involved a nutation movement in the stance phase and a counter-nutation in the swing phase relative to the ilium. In models without SIJs, the displacement of the pelvis and loads of pelvic ligaments decreased, and the equivalent stress of the SIJs increased compared to the model with SIJs. The walking loads cause distortion of the entire pelvis, and stress concentration at the SIJ are seen due to the morphology of the pelvic ring. However, the SIJs help dissipate the resulting stresses, and the surrounding ligaments are likewise involved in load transmission.

Effect of Geometric Curvature on Collective Cell Migration in Tortuous Microchannel Devices　　　　　　　　　　　　　　　
M.B. Mazalan, M.A.B. Ramlan, J.H. Shin, T. Ohashi
Micromachines, 11, 7, 659, 2020, [Peer-reviewed], [Last author]

コラーゲン・トリペプチドの軟骨細胞に対する賦活作用　　　　　　　　　　　　　　　
大橋 俊朗, 山本 祥子, 松本 陽, 沼田 徳暁, 酒井 康夫, 佐藤 正明
応用薬理, 98, 1, 5, 2020, [Peer-reviewed]

Mechanical properties of a new thermally deformable mitral valve annuloplasty ring and its effects on the mitral valve.
Tatsuya Seki, Katsuyoshi Jimuro, Yasushige Shingu, Satoru Wakasa, Hiroki Katoh, Tomonori Ooka, Tsuyoshi Tachibana, Suguru Kubota, Toshiro Ohashi, Yoshiro Matsui
Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs, 22, 2, 126, 133, Jun. 2019, [Peer-reviewed], [Domestic magazines]
English, Scientific journal, Ideally, an annuloplasty ring's shape should be changed intraoperatively if mitral valve repair is unsuccessful because of a short coaptation length or systolic anterior motion. Several post-implantation adjustable rings have been developed, but they are not freely deformable and are unsuitable for asymmetric repair of the valvular annulus. We developed a novel thermally deformable mitral annuloplasty ring to address these problems and assessed the ring's mechanical properties and its effect on the mitral valve anatomy. This ring was made of polycaprolactone. Tensile and bending tests were performed to evaluate the ring's mechanical properties. The ratio of the transverse and septal-lateral length was determined as 4:3. Using 10 pig hearts, we measured the post-deformation coaptation length and minimum distance from the coaptation to the ventricular septum, which is a factor of abnormal systolic anterior motion of the mitral valve. In the mechanical tests, the ring's yield point was greater than the deformation force of the annulus in humans. In pigs with deformation from "4:3" to "4:2", the coaptation length was significantly increased in each mitral valve part. In pigs with deformation from "4:3" to "4:4", the minimum distance from the coaptation to the ventricular septum was significantly increased. Asymmetrical ring deformation increased the coaptation length only at the deformed area. In conclusion, this new thermally deformable mitral annuloplasty ring could be "order-made" to effectively change the coaptation length in all parts of the mitral valve and the distance from the coaptation to septum post-deformation via intraoperative heating.

Depletion of glycosphingolipids induces excessive response of chondrocytes under mechanical stress
S. Matsubara, T. Onodera, E. Maeda, D. Momma, M. Matsuoka, K. Homan, T. Ohashi, N. Iwasaki
Journal of Biomechanics, 94, 22, 30, 2019, [Peer-reviewed], [Corresponding author], [International Magazine]
English, Scientific journal, Glycosphingolipids (GSLs) are ubiquitous membrane components that play an indispensable role in maintaining chondrocyte homeostasis. To gain better insight into roles of GSLs, we studied the effects of GSL-deletion on the physiological responses of chondrocytes to mechanical stress. Mice lacking Ugcg gene (Ugcg-/-) were genetically generated to obtain GSL-deficient mice, and their chondrocytes from the joints were used for functional analyses in vitro culture experiments. The cells were seeded in a three-dimensional collagen gel and subjected to 5%, 10% or 16% cyclic tensile strain for either 3 or 24 h. The gene expressions of chondrocyte anabolic and catabolic factors, and the induction of Ca2+ signaling were analyzed. Our results revealed that chondrocytes derived from GSL-deficient mice exhibited an elevation in the expression of catabolic factors (ADAMTS-5, MMP-13) following the exposure to strain with amplitudes of 10%. Likewise, applying cyclic tensile strain with these amplitudes resulted in an increased Ca2+ oscillation ratio in chondrocytes from GSL-deficient as compared to the ratio from control mice. These results demonstrated that deletion of GSL stimulated the catabolic responses of chondrocytes to mechanical stress via the augmentation of the sensitivity to mechanical stress that may lead to the cartilage deterioration. These findings suggest that the regulation of the physiological responses of chondrocytes by GSLs could be a potential target in a therapeutic intervention in osteoarthritis.

軟骨細胞の力学的ストレス応答におけるスフィンゴ糖脂質の機能解析
松原 新史, 小野寺 智洋, 門間 太輔, 馬場 力哉, 本谷 和俊, 上徳 善太, 宝満 健太郎, 岩崎 倫政, 大橋 俊朗, 前田 英次郎
北海道整形災害外科学会雑誌, 60, 1, 145, 146, 北海道整形災害外科学会, Aug. 2018
Japanese

Enhanced gap junction intercellular communication inhibits catabolic and pro-inflammatory responses in tenocytes against heat stress　　　　　　　　　　　　　　　
E. Maeda, S. Kimura, M. Yamada, M. Tashiro, T. Ohashi
Journal of Cell Communication and Signaling, 11, 4, 369, 380, 2017, [Peer-reviewed], [Last author]

Temporal regulation of gap junctional communication between tenocytes subjected to static tensile strain with physiological and non-physiological amplitudes
Eijiro Maeda, Haicheng Pian, Toshiro Ohashi
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 482, 4, 1170, 1175, Jan. 2017, [Peer-reviewed]
English, Scientific journal

Relative contribution of physiological hydrostatic pressure and fluid shear stress to endothelial monolayer integrity
Toshiro Ohashi, Yoshiaki Sugaya, Naoya Sakamoto, Masaaki Sato
Biomedical Engineering Letters, 6, 1, 31, 38, Springer Verlag, 01 Feb. 2016, [Peer-reviewed]
English, Scientific journal

Mechano-regulation of gap junction communications between tendon cells is dependent on the magnitude of tensile strain
Eijiro Maeda, Toshiro Ohashi
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 465, 2, 281, 286, Sep. 2015, [Peer-reviewed]
English, Scientific journal

Three-dimensional imaging of biological cells with picosecond ultrasonics
Sorasak Danworaphong, Motonobu Tomoda, Yuki Matsumoto, Osamu Matsuda, Toshiro Ohashi, Hiromu Watanabe, Masafumi Nagayama, Kazutoshi Gohara, Paul H. Otsuka, Oliver B. Wright
APPLIED PHYSICS LETTERS, 106, 16, Apr. 2015, [Peer-reviewed]
English, Scientific journal

Evaluation of intercellular diffusivity of hyperthermia-exposed tenocytes by using FLIP experiment
OHASHI TOSHIRO, TASHIRO MASATAKA, MAEDA EIJIRO
Transactions of Japanese Society for Medical and Biological Engineering, 53, S234_03, S234_03, Japanese Society for Medical and Biological Engineering, 2015
Japanese, Core temperature of tendon is known to elevate to approximately 43°C under severe mechanical loading in horse as well as in human. This elevated temperature could be a potential etiology of tendinopathy; however, little is known about how hyperthermia affects tenocyte functions. Therefore, the present study hypothesized that such high temperature affects gap junction communication between tenocytes and upregulated tenocyte catabolism. Gap junction communication was evaluated using fluorescence loss in photobleaching (FLIP) protocol, with a mathematical model to estimate both intracellular and intercellular diffusion coefficients from FLIP result. It was exhibited that intercellular diffusion coefficient in tenocytes exposed to 43°C for 30 minutes was significantly larger than that in tenocytes exposed to 37°C. In addition, mRNA expression for catabolic markers, MMP-1 and IL-1β, was markedly upregulated but that for type I collagen was downregulated in 43°C treated group compared to 37°C treated group. Therefore, hyperthermia enhances gap junction communications and catabolic activities in tenocytes, suggesting that hyperthermia could be a trigger of inflammation response.

Development of fibrin gel-microgroove model for microvascularization by endothelial cells
Shaoyi Chen, Akihiro Morita, Irza Sukmana, Eijiro Maeda, Toshiro Ohashi
Journal of Biorheology, 29, 1, 19, 23, Japanese Society of Biorheology, 2015, [Peer-reviewed]
English, Scientific journal

Significant increase in Young's modulus of ATDC5 cells during chondrogenic differentiation induced by PAMPS/PDMAAm double-network gel: Comparison with induction by insulin
Eijiro Maeda, Takehiro Tsutsumi, Nobuto Kitamura, Takayuki Kurokawa, Jian Ping Gong, Kazunori Yasuda, Toshiro Ohashi
JOURNAL OF BIOMECHANICS, 47, 13, 3408, 3414, Oct. 2014, [Peer-reviewed]
English, Scientific journal

A microfluidic device towards shear stress analysis of clonal expanded endothelial cells
E. Weibull, S. Matsui, H. Andersson-Svahn, T. Ohashi
Journal of Biomechanical Science and Engineering, 9, 1, JBSE0006, JBSE0006, The Japan Society of Mechanical Engineers, 2014, [Peer-reviewed]
English, Scientific journal, The endothelial cells lining our cardiovascular system are constantly affected by shear stress, which can alter both the morphology and biological activity of the cells. Methods to study the basic shear stress response by creating stable flow profiles on the macro scale are well established, but they do not allow the generation of controlled high precision flow profiles. The emergence of microfluidic devices has enabled well-defined individual cellular response studies on endothelial cells in scale-relevant tools. However, so far, no shear stress studies on clonal heterogeneity have been published. We have developed a novel bioassay system to study several shear stress conditions in parallel on clonal expanded single cells. The device consists of a silicon/glass microwell slide with integrated polydimethylsiloxane microchannels, which delivers shear stress to cells in a well-controlled manner using micropumps. The flow behavior of the device was numerically characterized by computational fluid dynamics analysis, which confirmed that the desired fluid-imposed shear stress was obtained. Bovine aortic endothelial cells were cultured in the microwells for 24 hours and then subjected to a fluid shear stress of up to 2.0 Pa for 6 hours. The results showed that alignment and elongation of the endothelial cells along the flow direction were dependent on the level of shear stress applied. It was demonstrated that multiple experimental conditions can be examined simultaneously within a single device and the compartmentalized structure of the microwell slide can be used to ensure physical separation of cells in individual wells. Moreover, it was shown that the device could reduce consumption of expensive reagents and enable screening of rare samples.

Tenocyte anabolic and catabolic response to elevation in intracellular tension
Eijiro Maeda, Megumi Sugimoto, Youtaro Kosato, Chi Tat Poon, Belinda Pingguan-Murphy, Toshiro Ohashi
Journal of Biorheology, 28, 1, 16, 20, Japanese Society of Biorheology, 2014, [Peer-reviewed]
English, Scientific journal

A new experimental system for simultaneous application of cyclic tensile strain and fluid shear stress to tenocytes in vitro
Eijiro Maeda, Yasufumi Hagiwara, James H-C. Wang, Toshiro Ohashi
BIOMEDICAL MICRODEVICES, 15, 6, 1067, 1075, Dec. 2013, [Peer-reviewed]
English, Scientific journal

Biomechanics of the spinal cord and the pia mater
Hiroshi Ozawa, Takeo Matsumoto, Toshiro Ohashi, Masaaki Sato
Neuroprotection and Regeneration of the Spinal Cord, 61, 74, Springer Japan, 01 Nov. 2013, [Peer-reviewed]
English, In book

Microfluidic device for generating a stepwise concentration gradient on a microwell slide for cell analysis
Emilie Weibull, Shunsuke Matsui, Manabu Sakai, Helene Andersson Svahn, Toshiro Ohashi
Biomicrofluidics, 7, 6, 064115-1, 064115-12, 01 Nov. 2013, [Peer-reviewed]
English, Scientific journal

DNゲルによるATDC5細胞の軟骨分化誘導に関する力学的機序の解明 1細胞の力学的特性の変化とアクチン修飾タンパク質発現との関連
前田 英次郎, 堤 健博, 黒川 孝幸, 北村 信人, Gong Jian Ping, 安田 和則, 大橋 俊朗
日本整形外科学会雑誌, 87, 8, S1408, S1408, (公社)日本整形外科学会, Aug. 2013
Japanese

Cytoskeletal tension modulates MMP-1 gene expression from tenocytes on micropillar substrates
Eijiro Maeda, Megumi Sugimoto, Toshiro Ohashi
JOURNAL OF BIOMECHANICS, 46, 5, 991, 997, Mar. 2013, [Peer-reviewed]
English, Scientific journal

Evaluation of Rupture Properties of Thoracic Aortic Aneurysms in a Pressure-Imposed Test for Rupture Risk Estimation
Shukei Sugita, Takeo Matsumoto, Toshiro Ohashi, Kiichiro Kumagai, Hiroji Akimoto, Koichi Tabayashi, Masaaki Sato
Cardiovascular Engineering and Technology, 3, 1, 41, 51, Mar. 2012, [Peer-reviewed]
English, Scientific journal

Development of a microfluidic concentration gradient generator on a microwell slide for high-throughput cell analysis　　　　　　　　　　　　　　　
Emilie Weibull, Shunsuke Matsui, Helene Andersson-Svahn, Toshiro Ohashi
Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012, 1573, 1575, Chemical and Biological Microsystems Society, 2012
English, International conference proceedings

Endothelial cell responses to fluid shear stress: From methodology to applications
Toshiro Ohashi, Masaaki Sato
Single and Two-Phase Flows on Chemical and Biomedical Engineering, 579, 599, Bentham Science Publishers Ltd., 2012, [Peer-reviewed]
English, In book

Preface
Shinsuk Park, Kyehan Rhee, Toshiro Ohashi
Journal of Biomechanical Science and Engineering, 7, 4, 335, 2012, [Peer-reviewed]
English, Scientific journal

Micropillar-integrated device for monitoring dynamic regulation of traction forces during cell migration
Eijiro Maeda, Akito Sugawara, Justin J. Cooper-White, Toshiro Ohashi
2011 Int. Symp. on Micro-NanoMechatronics and Human Science, Symp. on "COE for Education and Research of Micro-Nano Mechatronics", Symposium on "Hyper Bio Assembler for 3D Cellular System Innovation", 16, 19, 2012, [Peer-reviewed]
English, International conference proceedings

SIMULTANEOUS MEASUREMENT OF MORPHOLOGY AND TRACTION FORCES OF ENDOTHELIAL CELLS UNDER FLUID SHEAR STRESS
Toshiro Ohashi, Yusaku Niida, Ryoichi Tanaka, Masaaki Sato
PROCEEDINGS OF THE ASME SUMMER BIOENGINEERING CONFERENCE, PTS A AND B, 245, 246, 2012, [Peer-reviewed]
English, International conference proceedings

胸部大動脈瘤の拍動特性から破裂圧力が推定できるか？
杉田修啓, 松本健郎, 大橋俊朗, 熊谷紀一郎, 秋元弘治, 田林 晄一, 佐藤 正明
脈管学, 52, 277, 283, Japanese College of Angiology, 2012, [Peer-reviewed]
Japanese, Scientific journal, To predict the rupture of thoracic aortic aneurysms (TAAs), the relationship between stiffness and rupture pressure was investigated in a pressure-imposed test. Each quadrilateral (ca. 20×20 mm²) specimen of human TAAs or porcine thoracic aortas (PTAs) was pressurized until rupture or up to 4500 mmHg. Tension per unit length (T) and strain (ε) of the specimen were calculated from loaded pressure (P) and deformations of the specimen. Stiffness (S) was determined as the slope of the T-ε curve. Blood pressure in vivo (P_vivo) was estimated from P, T, and diameter of the specimen. Stiffness of PTA specimens increased with an increase in P_vivo, while that of TAA specimens reached a plateau in a low-P_vivo region. To evaluate this phenomenon quantitatively, a yielding parameter (τ_P), i.e., P_vivo at which the stiffness S reached a plateau level, was determined by fitting an equation S=C_P{1–exp(–P_vivo/τ_P)} to the S-P_vivo curve. The parameter τ_P correlated significantly with the rupture pressure in vivo. This parameter also correlated significantly with the area fraction of collagen, indicating that collagen composition caused changes in the τ_P in TAA. Since the yielding parameter can be obtained from clinical data, τ_P can be used for rupture risk estimation.

Analysis and techniques for controlling kinesin-driven microtubules in nanoscale transport systems　　　　　　　　　　　　　　　
S. Sugita, N. Sakamoto, T. Ohashi, M. Sato
Proceedings of the Tohoku University Global Centre of Excellence Programme, 144, 150, 2012
English, International conference proceedings

Combined stimulation with cyclic stretching and hypoxia increases production of matrix metalloproteinase-9 and cytokines by macrophages
Koki Oya, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 412, 4, 678, 682, Sep. 2011, [Peer-reviewed]
English, Scientific journal

Stretch along the craniocaudal axis improves shape recoverability of the spinal cord
Hiroshi Ozawa, Takeo Matsumoto, Toshiro Ohashi, Masaaki Sato, Eiji Itoi
JOURNAL OF BIOMECHANICS, 44, 12, 2313, 2315, Aug. 2011, [Peer-reviewed]
English, Scientific journal

Modulation of traction forces of isolated tenocytes by substrate stiffness
Megumi Sugimoto, Eijiro Maeda, Toshiro Ohashi
ASME 2011 Summer Bioengineering Conference, SBC 2011, 875, 876, 2011, [Peer-reviewed]
English, International conference proceedings

Role of p120-catenin in the morphological changes of endothelial cells exposed to fluid shear stress
Naoya Sakamoto, Kei Segawa, Makoto Kanzaki, Toshiro Ohashi, Masaaki Sato
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 398, 3, 426, 432, Jul. 2010, [Peer-reviewed]
English, Scientific journal

Effect of spatial gradient in fluid shear stress on morphological changes in endothelial cells in response to flow
Naoya Sakamoto, Naoki Saito, Xiaobo Han, Toshiro Ohashi, Masaaki Sato
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 395, 2, 264, 269, Apr. 2010, [Peer-reviewed]
English, Scientific journal

Modification of the descending thoracic aortic anastomotic site using biodegradable felt: Study in a canine model with or without basic fibroblast growth factor
Hidenori Fujiwara, Yoshikatsu Saiki, Mitsuru Sato, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato, Yasuhiko Tabata, Koichi Tabayashi
JOURNAL OF VASCULAR SURGERY, 51, 1, 194, 202, Jan. 2010, [Peer-reviewed]
English, Scientific journal

Size sorting of kinesin-driven microtubules with topographical grooves on a chip
Shukei Sugita, Tatsuya Murase, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
LAB ON A CHIP, 10, 6, 755, 761, 2010, [Peer-reviewed]
English, Scientific journal

T0201-2-1 Morphological Responses of Myofibroblasts to Cyclic Stretch
KOHATA Kengo, MAEDA Eijiro, OHASHI Toshiro
The proceedings of the JSME annual meeting, 2010, 143, 144, The Japan Society of Mechanical Engineers, 2010
Japanese, The present study hypothesized that initial geometrical shapes of cutaneous wound and the major axis of the wound to the direction of stretch could influence myofibroblast realignment observed in the maturation phase of healing process. Human dermal fibroblasts were differentiated into myofibroblasts with a treatment of TGF-β1. The cells were seeded onto a PDMS chamber either in a monolayer or in a colony of the following shapes: circle, and track fields both parallel and vertical to the stretch. Cyclic tensile stretch, with an amplitude of 20%, was provided at 1 Hz for 6 hours. Myofibroblasts seeded in the circle and the parallel track exhibited a similar response of realigning ±1:70° to the strain axis with uniformly distributed myofibroblasts in the whole area. By contrast, the cells seeded in the shape of vertical track demonstrated realignment to no specific direction. Findings supports our hypothesis, indicating that the shape and the orientation of wound influences healing processes through myofibroblasts realignment.

Preface
Toshiro Ohashi, Helene Andersson-Svahn
Journal of Biomechanical Science and Engineering, 5, 3, 185, 2010, [Peer-reviewed]
English, Scientific journal

Effect of spatial gradient of shear stress on morphological responses of endothelial cells to flow　　　　　　　　　　　　　　　
N. Sakamoto, N. Saito, T. Ohashi, M. Sato
Proceedings of 13th International Symposium of Tohoku University Global COE programme, 64, 67, 2010
English, International conference proceedings

Biomechanical contribution of cytoskeletal structures to traction forces in cultured smooth muscle cells
Toshiro Ohashi, Norifumi Kameda, Shouji Nakamura, Masaaki Sato
Journal of Biomechanical Science and Engineering, 5, 3, 262, 271, 2010, [Peer-reviewed]
English, Scientific journal

A microwell array device with integrated microfluidic components for enhanced single-cell analysis
Sara Lindstrom, Kiichiroh Mori, Toshiro Ohashi, Helene Andersson-Svahn
ELECTROPHORESIS, 30, 24, 4166, 4171, Dec. 2009, [Peer-reviewed]
English, Scientific journal

Tagged cine magnetic resonance imaging with a finite element model can predict the severity of retrosternal adhesions prior to redo cardiac surgery
Ichiro Yoshioka, Yoshikatsu Saiki, Azusa Ichinose, Kei Takase, Shoki Takahashi, Toshiro Ohashi, Masaaki Sato, Koichi Tabayashi
JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY, 137, 4, 957, 962, Apr. 2009, [Peer-reviewed]
English, Scientific journal

A versatile micro-mechanical tester for actin stress fibers isolated from cells
Tsubasa S. Matsui, Shinji Deguchi, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
BIORHEOLOGY, 46, 5, 401, 415, 2009, [Peer-reviewed]
English, Scientific journal

Novel bioassay system for single cells　　　　　　　　　　　　　　　
Toshiro Ohashi, Kiichiroh Mori, Sara Lindström, Helene Andersson-Svahn
Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, 1171, 1173, Chemical and Biological Microsystems Society, 2009
English, International conference proceedings

Specificity of Traction Forces to Extracellular Matrix in Smooth Muscle Cells
T. Ohashi, H. Ichihara, N. Sakamoto, M. Sato
IFMBE Proceedings, 23, 2192, 2193, 2009, [Peer-reviewed]
English, International conference proceedings

Biaxial tensile properties of thoracic aortic aneurysm tissues
Takeo Matsumoto, Tomohiro Fukui, Toshihiro Tanaka, Naoko Ikuta, Toshiro Ohashi, Kiichiro Kumagai, Hiroji Akimoto, Koichi Tabayashi, Masaaki Sato
Journal of Biomechanical Science and Engineering, 4, 4, 518, 529, 2009, [Peer-reviewed]
English, Scientific journal

High wall shear stress gradient suppress morphological responses of endothelial cells to fluid flow
M. Sato, N. Saito, N. Sakamoto, T. Ohashi
IFMBE Proceedings, 25, 4, 312, 313, 2009, [Peer-reviewed]
English, International conference proceedings

HIGH SHEAR STRESS INDUCES PRODUCTION OF MATRIX METALLOPROTEINASE IN ENDOTHELIAL CELLS
Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
PROCEEDINGS OF THE ASME SUMMER BIOENGINEERING CONFERENCE 2008, PTS A AND B, 61, 62, 2009, [Peer-reviewed]
English, International conference proceedings

DYNAMIC CONTROL OF SLIDING DIRECTIONS OF KINESIN-DRIVEN MICROTUBULES WITH ROTATING ELECTRIC FIELDS
Shulkel Sugita, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
PROCEEDINGS OF THE ASME SUMMER BIOENGINEERING CONFERENCE 2008, PTS A AND B, 315, 316, 2009, [Peer-reviewed]
English, International conference proceedings

Novel image analysis for trajectory of microtubules gliding on kinesins with tip detection
S. Sugita, N. Sakamoto, T. Ohashi, M. Sato
Journal of Biomechanical Science and Engineering, 4, 3, 404, 414, The Japan Society of Mechanical Engineers, 2009, [Peer-reviewed]
English, Scientific journal, Control of the gliding directions of kinesin-driven microtubules (MTs) in vitro has good feasibility for the development of nano-scale transport systems. A requirement for the control of transporters in these systems includes detecting the positions of gliding MTs; however, no studies have reported on the monitoring of the positions of gliding MTs. Here, we suggest an algorithm to detect tip coordinates of gliding MTs by binarization, skeletonization, and filtration of fluorescent images of MTs. The algorithm was first applied to artificially drawn segments with given lengths (10-80 pixels), widths (1-10 pixels), and curvature radii (20-120 pixels) to verify the effect of the sizes of MTs on accuracy of tip coordinates extracted by the algorithm, and error was estimated by referring to the true coordinates. The estimated errors were as small as 2 pixels in the width and were not affected by the length and the curvature radius, indicating that our algorithm is useful to extract the tips of MTs. The algorithm was subsequently applied to images of gliding MTs. Since distances from the trajectories of the MTs to the centers of gravity of the MTs (3.7 ± 2.1 pixels) were significantly larger than those to the tips (1.9 ± 0.5 pixels), the use of the tips as representative points of gliding MTs was verified. A detection method using tips of MTs, as suggested in this study, may be a useful technique for monitoring each MT in nanoscale transport systems.

Characterization of motility properties of kinesin-driven microtubules towards nano-scale transporter: Focusing on length of microtubules and kinesin density
S. Sugita, N. Sakamoto, T. Ohashi, M. Sato
Journal of Biomechanical Science and Engineering, 3, 4, 510, 519, The Japan Society of Mechanical Engineers, Dec. 2008, [Peer-reviewed]
English, Scientific journal, Kinesins, biomolecular motors moving along microtubules (MTs) in cells, can potentially be utilized as nano-scale transport systems with an inverted gliding assay, in which the MTs glide on a kinesin-coated surface. Although the key requirements include controls of gliding direction and velocity of MTs, the details of motility properties of MTs have not been well known. In this study, we quantitatively measured angular and gliding velocities, particularly focusing on the effects of MT length and kinesin density. The gliding assay of MTs of up to 20 μm in length was performed on a substrate coated with the kinesin density of 7.5, 38, and 75 μg/ml that resulted in the kinesin spacing of 7.8, 4.2, and 3.1 μm, respectively. The angular velocity for MTs shorter than kinesin spacings significantly decreased with increasing their length, and that for MTs longer than kinesin spacings was not affected by their length. Moreover, the angular velocity was substantially higher at lower kinesin density. These results suggest that both the number of associated kinesins with MTs and the kinesin spacings may contribute to the gliding direction. In contrast, the gliding velocity was independent of the MT length, ranging from 0.3 to 0.5 μm/s with decreasing the kinesin density. This may potentially imply the existence of an underlying mechanism with respect to the number of kinesins per the unit length of MTs. Towards development of high throughput nano-scale transport systems, long MTs and low kinesin densities would be effective for high directionality and high velocity, respectively.

Remodeling of Endothelial Cell Nucleus Exposed to Three Different Mechanical Stimuli
Toshiro Ohashi, Kazuhiko Hanamura, Daisaku Azuma, Naoya Sakamoto, Masaaki Sato
Journal of Biomechanical Science and Engineering, 3, 2, 63, 74, 2008, [Peer-reviewed]
English, Scientific journal

Regulation of cyclic longitudinal mechanical stretch on proliferation of human bone marrow mesenchymal stem cells
Guanbin Song, Yang Ju, Hitoshi Soyama, Toshiro Ohashi, Masaaki Sato
MCB Molecular and Cellular Biomechanics, 4, 4, 201, 210, Dec. 2007, [Peer-reviewed]
English, Scientific journal

Experimental estimation of preexisting tension in single actin stress fiber of vascular cells
S. Deguchi, T. Ohashi, M. Sato
Biomechanics at Micro- and Nanoscale Levels, 60, 71, World Scientific Publishing Co., 01 Jan. 2007, [Peer-reviewed]
English, In book

Biomechanical role of intracellular structures in smooth muscle cells estimated by traction force measurements
Toshiro Ohashi, Shouji Nakamura, Naoya Sakamoto, Masaaki Sato
2007 INTERNATIONAL SYMPOSIUM ON MICRO-NANO MECHATRONICS AND HUMAN SCIENCE, VOLS 1 AND 2, 400, +, 2007, [Peer-reviewed]
English, International conference proceedings

Editorial
S. Deguchi, K. Maeda, T. Ohashi, M. Sato
Journal of Biomechanics, 39, 7, 1362, 2006, [Peer-reviewed]
English, Scientific journal

Mechanical properties of stress fiber in adherent vascular cells characterized by in vitro micromanipulation
Shinji Deguchi, Toshiro Ohashi, Masaaki Sato
FUTURE MEDICAL ENGINEERING BASED ON BIONANOTECHNOLOGY, PROCEEDINGS, 71, +, 2006, [Peer-reviewed]
English, International conference proceedings

Frequency of shear stress modulates morphology and integrin expression of vascular endothelial cells
Kazushi Ito, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
FUTURE MEDICAL ENGINEERING BASED ON BIONANOTECHNOLOGY, PROCEEDINGS, 103, +, 2006, [Peer-reviewed]
English, International conference proceedings

Biomechanical approach to endothelial cell responses to fluid shear stress and hydrostatic pressure
Toshiro Ohashi, Naoya Sakamoto, Masaaki Sato
FUTURE MEDICAL ENGINEERING BASED ON BIONANOTECHNOLOGY, PROCEEDINGS, 23, +, 2006, [Peer-reviewed]
English, International conference proceedings

Hydrostatic pressure influences sub-cellular localization of beta-catenin of vascular endothelial cells
Katherine Baria, Yoshiaki Sugaya, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato
FUTURE MEDICAL ENGINEERING BASED ON BIONANOTECHNOLOGY, PROCEEDINGS, 61, +, 2006, [Peer-reviewed]
English, International conference proceedings

Effect of strain rate on tensile properties of stress fibers isolated from cultured smooth muscle cells
Tsubasa Matsui, Shinji Deguchi, Toshiro Ohashi, Masaaki Sato
FUTURE MEDICAL ENGINEERING BASED ON BIONANOTECHNOLOGY, PROCEEDINGS, 129, +, 2006, [Peer-reviewed]
English, International conference proceedings

Control of cell morphology and measurement of traction forces of smooth muscle cells using microfabricated substrates
Toshiro Ohashi, Junichi Yamazaki, Norifumi Kameda, Masaaki Sato
2006 IEEE INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE, 140, +, 2006, [Peer-reviewed]
English, International conference proceedings

吸収性素材フェルトの吻合部大動脈壁に及ぼす影響に関する研究
藤原 英記, 小田, 克彦, 齋木, 佳克, 吉岡, 一朗, 河津, 聡, 佐藤, 真一, 坂元, 尚哉, 大橋, 俊朗, 佐藤, 正明, 田畑, 泰彦, 田林 晄一
The Japanese Journal of THORACIC AND CARDIOVASCULAR SURGERY, 53, Suppl.II, 395, 395, シュプリンガー・ジャパン(株), Sep. 2005
Japanese

Mechanical properties and function of the spinal pia mater.
Hiroshi Ozawa, Takeo Matsumoto, Toshiro Ohashi, Masaaki Sato, Shoichi Kokubun
Journal of neurosurgery. Spine, 1, 1, 122, 7, Jul. 2004, [International Magazine]
English, Scientific journal, OBJECT: The pia mater has received little attention regarding its function in the deformation of the spinal cord under compression. In this study the mechanical properties and function of the spinal pia mater were investigated using three methods. METHODS: Spinal cord segments were excised from rabbits. The elastic modulus of the pia mater was measured by performing a tensile test using specimens with the pia mater intact and ones with the pia mater stripped off. The stiffness of the spinal cord was examined by performing a compression test with specimens containing an intact pia mater and ones with a pia mater that was incised at both sides. The cross-sectional area and circumference of the spinal cord were measured on axial views of magnetic resonance images in patients with cervical disc herniations before and after surgery. The pia mater had an elastic modulus of 2300 kPa, which was 460 times higher than that of spinal cord parenchyma. By covering the parenchyma, it tripled the overall elastic modulus of the spinal cord. The pia mater increased the stiffness of the spinal cord and enhanced its shape recovery after removal of the compression. The cross-sectional area of the spinal cord increased after surgery, whereas the circumference of the spinal cord changed little. CONCLUSIONS: The pia mater firmly covers the spinal cord and has a high elastic modulus; it therefore provides a constraint on the spinal cord surface. It prevents elongation of the circumference and produces a large strain energy that is responsible for shape restoration following decompression.

Finite element analysis of sheared endothelial cells using structural optimization method　　　　　　　　　　　　　　　
S. Seo, T. Ohashi, T. Matsumoto, M. Sato
Proceedings of The First International Symposium on Advanced Fluid Information, 143, 146, 2001
English, International conference proceedings

Surface topography measurement and intracellular stress analysis of cultured endothelial cells exposed to fluid shear stress
T Ohashi, H Sugawara, T Matsumoto, M Sato
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 43, 4, 780, 786, Dec. 2000, [Peer-reviewed]
English, Scientific journal

An application of the pipette technique to the measurement of local mechanical properties of aortic walls　　　　　　　　　　　　　　　
M. Sato, T. Matsumoto, T. Ohashi
Proceedings of Toyota International Symposium on Human Life Support Biomechanics, 147, 154, 2000
English, International conference proceedings

Intramural distribution of elastic moduli in thoracic aortas and its relationship to histology: Comparison between porcine and bovine thoracic aortas
T Ohashi, Y Kato, T Matsumoto, M Sato
JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 42, 3, 568, 573, Sep. 1999, [Peer-reviewed]
English, Scientific journal

Local elastic moduli of aortic walls measured by pipette aspiration technique　　　　　　　　　　　　　　　
T. Ohashi, T. Matsumoto, T. Aoki, M. Sato
Proceedings of 4th China-Japan-USA-Singapore Conference on Biomechanics, 115, 118, 1995
English, International conference proceedings

有限要素法による直立二足歩行時の仙腸関節の動きと負荷変化の解析　　　　　　　　　　　　　　　
黒澤 大輔, 豊原 涼太, Hammer Niels, Uwe Lingslebe, 本田 啓太, 関口 雄介, 出江 紳一, 村上 栄一, 小澤 浩司, 大橋 俊朗, Journal of Spine Research, 11, 3, 456, 456, Mar. 2020
(一社)日本脊椎脊髄病学会, Japanese

有限要素法による直立二足歩行時の仙腸関節の動きと負荷変化の解析　　　　　　　　　　　　　　　
黒澤 大輔, 豊原 涼太, Hammer Niels, Uwe Lingslebe, 本田 啓太, 関口 雄介, 出江 紳一, 村上 栄一, 小澤 浩司, 大橋 俊朗, Journal of Spine Research, 11, 3, 456, 456, Mar. 2020
(一社)日本脊椎脊髄病学会, Japanese

Finite element analysis of sacroiliac joint motion and restriction received from ligaments
TOYOHARA Ryota, KUROSAWA Daisuke, HAMMER Niels, WERNER Michael, HONDA Keita, SEKIGUCHI Yusuke, IZUMI Shin-Ichi, MURAKAMI Eiichi, OZAWA Hiroshi, OHASHI Toshiro, The Proceedings of the JSME Conference on Frontiers in Bioengineering, 2020.31, 1C14, 2020
The Japan Society of Mechanical Engineers, Japanese

軟骨細胞の力学的ストレス応答におけるスフィンゴ糖脂質の機能解析　　　　　　　　　　　　　　　
松原 新史, 小野寺 智洋, 門間 太輔, 馬場 力哉, 本谷 和俊, 上徳 善太, 宝満 健太郎, 岩崎 倫政, 大橋 俊朗, 前田 英次郎, 北海道整形災害外科学会雑誌, 60, 1, 145, 146, Aug. 2018
北海道整形災害外科学会, Japanese

軟骨細胞の力学的ストレス応答におけるスフィンゴ糖脂質の機能解析　　　　　　　　　　　　　　　
松原 新史, 小野寺 智洋, 門間 太輔, 馬場 力哉, 本谷 和俊, 上徳 善太, 宝満 健太郎, 岩崎 倫政, 前田 英次郎, 大橋 俊朗, 北海道整形災害外科学会雑誌, 59, 2, 253, 254, Mar. 2018
北海道整形災害外科学会, Japanese

軟骨細胞の力学的ストレス応答におけるスフィンゴ糖脂質の機能解析
松原新史, 小野寺智洋, 前田英次郎, 門間太輔, 馬場力哉, 本谷俊彦, 上徳善太, 宝満健太郎, 大橋俊朗, 大橋俊朗, 岩崎倫政, 日本整形外科学会雑誌, 91, 8, S1774, S1774, 31 Aug. 2017
(公社)日本整形外科学会, Japanese

軟骨細胞の力学的ストレス応答におけるスフィンゴ糖脂質の機能解析　　　　　　　　　　　　　　　
松原新史, 小野寺智洋, 前田英次郎, 門間太輔, 馬場力哉, 本谷和俊, 上徳善太, 宝満健太郎, 大橋俊朗, 岩崎倫政, 第30回日本軟骨代謝学会, 120, Mar. 2017

Depletion Of Glycosphingolipids Induces The Excessive Response Of Chondrocytes Under Mechanical Stress Condition.　　　　　　　　　　　　　　　
Shinji Matsubara, Tomohiro Onodera, Eijiro Maeda, Daisuke Momma, Masatake Matsuoka, Rikiya Baba, Kazutoshi Hontani, Zenta Joutoku, Kentarou Homan Homan, Toshiro Ohashi, Norimasa Iwasaki, The 63th Annual Meeting of Orthopaedic Research Society (ORS), Mar. 2017
English

2D15 Temporal characterization of gap junction communication between tenocytes under tensile strain in vitro
PIAN Haicheng, MAEDA Eijiro, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2016, 28, "2D15, 1"-"2D15-4", 09 Jan. 2016
Gap junction communication is known to play essential roles in tenocyte functions in response to mechanical loading. In our previous study, it was exhibited that an application of static tensile strain with a physiological amplitude for 1h promoted gap junction communication in tenocytes while overloading strain suppressed gap junction communication. However, temporal regulation of gap junction communication during an extended static loading has not been characterized. Accordingly, the present study tested a hypothesis that gap junction communication is regulated in a manner depending on the duration of mechanical loading. Gap junction communication was investigated using a fluorescence loss in photobleaching (FLIP) technique. It was demonstrated that the level of gap junction communication was fluctuated under physiological 4% static strain during 24h period, while it was gradually increased under 8% static strain., The Japan Society of Mechanical Engineers, English

2D33 Contribution of intercellular communications to inflammatory responses of tenocytes to thermal stimulation
MAEDA Eijiro, TASHIRO Masataka, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2016, 28, "2D33, 1"-"2D33-5", 09 Jan. 2016
Tendinopathy has been one of major health concerns in orthopaedic surgery, not only for active athletes but also for others like office workers. Although the exact etiology of tendinopathy has yet to be elucidated, it has been demonstrated that tendon core temperature elevated up to 43 to 45 degree Celsius when humans or racehorses are subjected to extensive exercises (harsh running). A long exposure to such high temperature could induce cell death. However, effects of the exposure to the high temperature for relatively short terms (simulating running activity) on tenocyte functions are still not understood. Therefore, the present study was performed to investigate how tenocyte anabolism and catabolism are altered by a short thermal stimulation. In addition, the present study tested a hypothesis that such alterations of tenocyte functions are dependent in the presence of gap junction intercellular communication (GJIC). It was demonstrated that tenocyte GJIC was not significantly altered by a 30 minutes exposure to 43 degree. However, catabolic and inflammatory gene expressions were significantly upregulated following a 24 h post-heating culture period. With the presence of GJ blocker, upregulation of catabolic genes by the thermal stimulation was inhibited, although inflammatory gene expression was further enhanced. These results may indicate that GJIC in part contribute to alterations in tenocyte functions in response to thermal stimulation in a complicated manner., The Japan Society of Mechanical Engineers, Japanese

高度物理刺激と生体応答(トピックス)
佐藤 岳彦, 大橋 俊朗, 川野 聡恭, 白樫 了, 日本機械学會誌, 118, 1165, 758, 758, 05 Dec. 2015
一般社団法人日本機械学会, Japanese

OS20-5 Novel Experimental Device for Applying Cyclic Tensile Strain and Fluid Shear Stress to Tenocytes in Vitro(Experimental biomechanics and bioengineering 2,OS20 Experimental biomechanics and bioengineering,BIOMECHANICS)
Ohashi Toshiro, Hagiwara Yasufumi, Wang James H-C, Maeda Eijiro, Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics, 2015, 14, 255, 255, 04 Oct. 2015
The Japan Society of Mechanical Engineers, English

J0220101 Intracellular tension-dependent morphology changes of isolated tenocytes in response to IL-1B stimulation
MAEDA Eijiro, Muramatsu Tomomi, Ohashi Toshiro, Mechanical Engineering Congress, Japan, 2015, "J0220101, 1"-"J0220101-4", 13 Sep. 2015
Tendon is known to remodel its structure and alter mechanical properties in response to changes in its mechanical environment. Tendon cells, tenocytes, are thought to play significant roles in tendon tissue remodelling, by responding to mechanical stress. Like other adherent cells, tenocytes exert traction forces to their substrate when the cells attach to the substrate. Cell traction forces are thought to reflect the level of intracellular tension generated in actin cytoskeletons. It has been shown that intracellular tension level is a regulatory factor of tenocyte catabolism. Accordingly, the present study hypothesized that tenocyte response to interleukin-1β is dependent on the level of intracellular tension. Tenocytes, isolated from rabbit Achilles tendons, were seeded microfabricated, elastic micropillar substrates, and were subjected to the treatment of IL-1β at four different concentrations. It was demonstrated that tenocyte traction force level was dependent on the elastic modulus of micropillar substrates. In addition, cells on softer substrates were more prone to the stimulation of the catabolic agent, exhibiting a greater change in cell morphology. These results suggest that tenocytes with a low level of intracellular tension, which implies that the cells are catabolic, are stimulated by catabolic/inflammatory agents and further enhance their catabolism., The Japan Society of Mechanical Engineers, Japanese

1C43 Measurement of mechanical properties of chondrocytes from glycosphingolipid knock-out mice with micropipette aspiration
NAKAJIMA Toshiaki, MAEDA Eijiro, MATSUBARA Shinji, MOMMA Daisuke, ONODERA Tomohiro, IWASAKI Norimasa, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2015, 27, 129, 130, 08 Jan. 2015
The Japan Society of Mechanical Engineers, Japanese

1C13 Effect of hyperthermia on tenocyte catabolism and intercellular communications
TASHIRO Masataka, MAEDA Eijiro, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2015, 27, 101, 102, 08 Jan. 2015
The Japan Society of Mechanical Engineers, Japanese

J0270204 Quantitative evaluation of effects of mechanical loading on intercellular communication between cultured tenocytes using FLIP
MAEDA Eijiro, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2014, "J0270204, 1"-"J0270204-4", 07 Sep. 2014
Gap junctions have been known to be involved in regulations of cell functions. It is also suggested that gap junction intercellular communications (GJICs) between tenocytes play an essential role in collagen synthesis in response to mechanical loadings. However, there were little knowledge on how GJICs are mechanically regulated and how changes in GJIC affect tenocyte functions. Accordingly, the present study has proposed a new numerical model to estimate intra- and intercellular diffusivity, based on one-dimensional diffusion theory, by fitting the model to data obtained from FLIP experiments, which visualises intercellular mass transport using a confocal laser microscope. Tenocytes were seeded within microgrooves integrated in a custom-made PDMS device, and were loaded with calcein-AM. FLIP experiment consisted of a series of instantaneous 100% power laser irradiation provided to one of tenocytes in a series every 2.6 second for 99 times, and fluorescence decay profiles of the targeted tenocyte and its neighbouring cells were obtained. Using the numerical model, intracellular and intercellular diffusion coefficient of tenocytes under static culture was estimated to be 25.3 and 1.06 μm^2/sec, respectively. The latter was significantly increased by an application of physiological, 4% tensile strain to the tenocytes, whereas that was significantly reduced by excessive, 8% tensile strain to the cells. Therefore, it can be concluded that physiological mechanical loading enhances intercellular communications, whereas non-physiological, overloading disrupt them., The Japan Society of Mechanical Engineers, Japanese

OS0612 Mechanical analysis of chondrocytes in response to impact loading
OHASHI Toshiro, NAKATA Yu, M&M材料力学カンファレンス, 2014, "OS0612, 1"-"OS0612-2", 19 Jul. 2014
Since articular chondrocytes are in vivo exposed to complex mechanical environment, it is important to study whether chondrocyte responses to such mechanical environment are closely related to articular cartilage diseases such as osteoarthritis. In this study, chondrocytes are exposed to an impact loading with drop tower impact testing and the associated cell deformation is examined based on actin filament structures. Cell aspect ratio, an index of cell deformation, was significantly decreased after impact loading, exhibiting a circular shape for the control group and an ellipsoidal shape for the impact groups. This finding suggests that chondrocytes can be deformed by impact loading, possibly leading to an alternation in cell physiological functions., The Japan Society of Mechanical Engineers, Japanese

2F13 Effects of double-network gel component PAMPS on chondrogenic differentiation in ATDC5 cells
TSUCHIYA Hitoshi, MAEDA Eijiro, KUROKAWA Takayuki, GONG Jian Ping, KITAMURA Nobuto, YASUDA Kazunori, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2014, 26, 481, 482, 10 Jan. 2014
The Japan Society of Mechanical Engineers, Japanese

A205 Effects of increase in cytoskeletal tension on tenocyte functions using micropillars
MAEDA Eijiro, SUGIMOTO Megumi, KOSATO Yotaro, OHASHI Toshiro, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2013, 24, 57, 58, 31 Oct. 2013
The Japan Society of Mechanical Engineers, Japanese

OS0712 Cell migration observation and traction force measurement using multichannel device
OHASHI Toshiro, SUGAWARA Akito, Justin Cooper-White, M&M材料力学カンファレンス, 2013, "OS0712, 1"-"OS0712-2", 12 Oct. 2013
Cell migration plays an important role in many physiological and pathological events, however, the mechanism of collective cell migration has not been well understood. This study performs traction force microscopy on migrating NIH 3T3 fibroblasts using a multichanel device. The device consists of a reservoir for cell culture and 24 microchannels with arrays of micropillars for traction force microscopy. Here, the effect of anisotropic properties in stiffness of substrate on collective cell migration is tested with ellipsoidal cross section of micropillars. The results showed that cells migrated into the microchannels and produced higher traction forces in the direction of major axis of micropillars. This finding suggests that cell can sense the stiffness of substrate and produce traction forces depending on the stiffness, resulting in difference in cell migration rate., The Japan Society of Mechanical Engineers, Japanese

J026036 Cell migration observation and traction force measurement using multichannel device
OHASHI Toshiro, SUGAWARA Akito, COOPER-WHITE Justin, Mechanical Engineering Congress, Japan, 2013, "J026036, 1"-"J026036-3", 08 Sep. 2013
Cell migration plays an important role in many physiological and pathological processes such as morphogenesis, wound healing, and tumor metastasis. Although the majority of such events occur with cells moving as a group, called collective cell migration, the mechanism of collective cell migrations has not been well understood. This study performs traction force microscopy on migrating NIH 3T3 fibroblasts by using a microfabricated device to clarify the mechanism of collective cell migration. The device consists of a reservoir for establishing a confluent cell monolayer and 24 microchannels with arrays of micropillars that are used for traction force microscopy. Here the effect of anisotropic properties in stiffness of substrate on cell migration is tested with ellipsoidal cross section of micropillars. Cells produced higher traction forces in the direction of major axis of micropillars. Moreover, cells migrated faster when the major axis of micropillars is parallel to the direction of microchannels. These results suggest that cell can sense the stiffness of substrate and produce traction forces depending on the stiffness, leading to modulation of cell migration rate., The Japan Society of Mechanical Engineers, Japanese

(1)Biomechanical Contribution of Cytoskeletal Structures to Traction Forces in Cultured Smooth Muscle Cells
大橋 俊朗, 亀田 憲史, 中村 昌司, 佐藤 正明, Journal of the Japan Society of Mechanical Engineers, 116, 1134, 289, 289, 05 May 2013
The Japan Society of Mechanical Engineers, Japanese

Double‐Networkゲル上で培養したATDC5細胞の軟骨分化メカニズム
前田英次郎, 堤健博, 黒川孝幸, 北村信人, GONG Jian Ping, 安田和則, 大橋俊朗, バイオエンジニアリング講演会講演論文集, 25th, 25, 221, 222, 08 Jan. 2013
The Japan Society of Mechanical Engineers, Japanese

A217 Study of modulation of cytoskeletal tension and functions of isolated tenocytes by micropillar technique
Sugimoto Megumi, Maeda Eijiro, Ohashi Toshiro, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2012, 23, 125, 126, 04 Oct. 2012
The Japan Society of Mechanical Engineers, Japanese

A212 Measurement of traction forces of sheared endothelial cells using micropillar device
Niida Yusaku, Sato Masaaki, Ohashi Toshiro, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2012, 23, 117, 118, 04 Oct. 2012
The Japan Society of Mechanical Engineers, Japanese

B213 Development of newly Designed Biochip for Cell Analysis Using Microfluidics Technology
Sakai Manabu, Weibull Emilie, Andersson-Svahn Helene, Ohashi Toshiro, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2012, 23, 151, 152, 04 Oct. 2012
The Japan Society of Mechanical Engineers, Japanese

J028034 Dynamics of Traction Forces of Sheared Vascular Endothelial Cells
NIIDA Yusaku, SATO Masaaki, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2012, "J028034, 1"-"J028034-3", 09 Sep. 2012
Vascular endothelial cells (ECs) are lining the entire vascular trees and constantly exposed to blood flow. ECs demonstrate elongation and orientation in response to blood flow and physiological functions of ECs are known to be affected by fluid shear stress. Adherent cells such as ECs are known to generate contractile forces to their substrate through focal adhesion sites as traction forces. Cell traction forces reveal not only intracellular mechanics but also physiological state. In order to monitor changes of traction forces of ECs in response to fluid flow, we have newly developed a flow-imposed device, in which a substrate with arrays of microfabricated elastomeric pillars is integrated at the bottom of a parallel plate flow chamber. The present study was performed to characterize spatio-temporal distributions of traction forces of ECs undergoing remodeling process to fluid shear stress and to examine the relationship between the changes of cell traction forces and cell morphology., The Japan Society of Mechanical Engineers, Japanese

J028023 Modulation of Cytoskeletal Tension Influences Cell Metabolism of Isolated Tenocytes
SUGIMOTO Megumi, MAEDA Eijiro, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2012, "J028023, 1"-"J028023-4", 09 Sep. 2012
Tendon is subjected to dynamic mechanical loading in vivo and thus effects of cyclic tensile loading on tenocyte metabolism have been well characterized. However, the relationship between cell metabolism and cytoskeletal tension has not been studied in detail. Elastic micropillars made from silicone elastomer (PDMS) have been proposed to measure cellular traction forces which reflect cytoskeletal tension. Micropillar substrates with three different stiffness were prepared by changing the height of the pillars. First, to examine the effects of the substrate stiffness, tenocytes isolated from bovine tendons were seeded on the micropillar substrates. At the end of 24 hrs incubation period, cellular traction forces were determined. Real-time qPCR was also performed to examine the expressions of type I collagen (anabolic gene) and MMP-1 (catabolic gene) mRNA from tenocytes. In addition, to examine the role of acto-myosin contractility, tenocytes were treated with myosin II inhibitor, blebbistatin at 20 hrs. It was found that there were significant increases in cellular traction forces with increasing stiffness of micropillar substrates. Although there were no significant differences in the expression level of type I collagen among the three substrates, significant increases were observed in the expression level of MMP-1 with decreasing in stiffness of substrate. Moreover, traction forces decreased and the expression level of MMP-1 increased with the treatment of blebbistatin. This may indicate that intracellular cytoskeletal tension, driven by acto-myosin contractility, could strongly influence tenocyte catabolism rather than anabolism., The Japan Society of Mechanical Engineers, Japanese

702 Relationship between mechanical properties and tensile strength of thoracic aortic aneurysms toward estimation of rupture risk
SUGITA Shukei, MATSUMOTO Takeo, OHASHI Toshiro, KUMAGAI Kiichiro, AKIMOTO Hiroji, TABAYASHI Koichi, SATO Masaaki, 東海支部総会講演会講演論文集, 2012, 61, "702, 1"-"702-2", 15 Mar. 2012
The Japan Society of Mechanical Engineers, Japanese

7C41 Measurement of traction forces during collective cell migration using multichannel device with micropillars
SUGAWARA Akito, MAEDA Eijiro, COOPER-WHITE Justin John, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2012, 24, "7C41, 1"-"7C41-2", 06 Jan. 2012
The Japan Society of Mechanical Engineers, Japanese

7C22 Development of novel biochip equipped with microfluidic concentration step generator
MATSUI Shunsuke, MAEDA Eijiro, WEIBULL Emilie, ANDERSSON-SVAHN Helene, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2012, 24, "7C22, 1"-"7C22-2", 06 Jan. 2012
The Japan Society of Mechanical Engineers, Japanese

7C42 Measurement of traction forces during morphological changes in sheared endothelial cells
NIIDA Yusaku, MAEDA Eijiro, SATO Masaaki, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2012, 24, "7C42, 1"-"7C42-2", 06 Jan. 2012
The Japan Society of Mechanical Engineers, Japanese

7F41 Substrate stiffness influences cell traction forces and cell metabolism of isolated tenocytes
SUGIMOTO Megumi, MAEDA Eijiro, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2012, 24, "7F41, 1"-"7F41-2", 06 Jan. 2012
The Japan Society of Mechanical Engineers, Japanese

7E42 Development of a new cell culture device for the study of tenocyte mechanobiology
HAGIWARA Yasufumi, MAEDA Eijiro, WANG James H.C., OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2012, 24, "7E42, 1"-"7E42-2", 06 Jan. 2012
The Japan Society of Mechanical Engineers, Japanese

ATDC5細胞の軟骨分化過程における力学特性計測
堤健博, 前田英次郎, 北村信人, 安田和則, 大橋俊朗, バイオエンジニアリング講演会講演論文集, 24th (CD-ROM), 24, ROMBUNNO.7F42, 1"-"7F42-2", 06 Jan. 2012
The Japan Society of Mechanical Engineers, Japanese

S022031 Measurement of traction forces during migration of fibroblasts using multichannel device with micropillars
SUGAWARA Akito, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2011, "S022031, 1"-"S022031-4", 11 Sep. 2011
Cell migration is essential for a variety of biological and pathological processes such as wound healing, inflammation and tumor metastasis. However, a mechanical field within a group of multiple cells during a collective migration has not been characterized well. In this study, a polydimethylsiloxane-made multichannel device was fabricated using photolithography and soft lithography, and was used to monitor traction forces generated by cells during migration. The device consists of a reservoir for establishing a confluent cell monolayer, attached with 24 microchannels for cell migration. Four patterns of micropillars were designed on the bottom surface of the microchannels to measure cell traction forces during migration on four combinations of substrate stiffness and topography. Collective cell migration from the reservoir into the microchannels was initiated when the channels were backfilled with culture medium. Migration rate of 5.7 pm/h was measured in the microchannel equipped with micropillars whose dimensions were 6.5 pm in height, 2 pm in diameter and 7 pm in spacing. In detail, cells on the moving front of the migration, leading cells, generated the traction forces toward the backward and the maximum magnitude of 14 nN was measured at their front side. Traction forces generated by the cells behind the leading cells directed backward at both the front and the rear sides. However, traction forces generated by the cells behind the second row directed random directions with smaller magnitudes compared to those on the front and the second lines. It is assumed that cells on the front line generated a large magnitude of traction forces and migrated actively as single cells, pulling adjacent cells forward, whereas the movement of cells after third row was restricted by mechanical linkages between their neighboring cells, generating a small magnitude of traction forces., The Japan Society of Mechanical Engineers, Japanese

S022024 Effect of Substrate Stiffness on Traction Forces of Isolated Tenocytes
SUGIMOTO Megumi, MAEDA Eijiro, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2011, "S022024, 1"-"S022024-4", 11 Sep. 2011
Tendon is subjected to dynamic mechanical loading in vivo. Effects of cyclic tensile loading on tenocyte metabolism have been characterized well. However, the relationship between cell metabolism and internal tension within cytoskeleton has not been studied in detail. Elastic micropillars made from silicone elastomer (PDMS) have been proposed to measure cellular traction forces which reflect cytoskeletal tension. Micropillar substrates with three different elastic moduli were prepared by changing the height of the pillars. After tenocytes were seeded on each substrate for 24 hours, traction forces were determined. Real-time qPCR was also performed to examine the expressions of type I collagen (anabolic gene) and MMP-1 (catabolic gene) mRNA from tenocytes on these substrates. It was found that there were significant increases in cellular traction forces with the elastic modulus of micropillar substrates. Although there were no significant differences in the expression level of type I collagen among three substrates, increases were observed in the expression level of MMP-1 with decreases in the elastic modulus of substrate. This may indicate that intracellular cytoskeletal tension strongly influences tenocyte catabolism rather than anabolism., The Japan Society of Mechanical Engineers, Japanese

S022021 Development of novel substrate with array of magnetic beads for cell culture
NIIDA Yusaku, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2011, "S022021, 1"-"S022021-3", 11 Sep. 2011
This paper presents development of a technique to control cell adhesion using an array of magnetic microbeads. Using MEMS techniques, we fabricated an array of microholes (3 gm in diameter and 2 gm in depth) on the surface of a glass substrate, to trap magnetic microbeads (2.8 gm in diameter) in the microholes. The glass substrate was integrated with a PDMS-made device and a suspension of magnetic microbeads was then introduced into the device by a syringe pump. The magnetic microbeads were coated with cell adhesive ligands prior to the loading. A permanent magnet was placed under the substrate and was used to direct microbeads into the microholes, followed by an introduction of cell suspension to the device. After a 24 hours incubation, it was observed that cells attached only to the magnetic microbeads, but not to the other parts of the glass surface. The current method of controlling cell adhesion would be useful to develop advanced cell culture system., The Japan Society of Mechanical Engineers, Japanese

S022035 Fluid-imposed experiment on endothelial cells cultured in novel bioassay system
MATSUI Shunsuke, OHASHI Toshiro, Mechanical Engineering Congress, Japan, 2011, "S022035, 1"-"S022035-4", 11 Sep. 2011
Single cell analysis has been of a great interest in bioengineering as it can highlight heterogeneity of individual cells in medical screening tests compared to conventional bulk analysis. We have been developing a novel bioassay system designed for single cell analysis. The device mainly consists of a silicon/glass microwell slide and a PDMS microchannel, and enables to supply reagents to microwells in a well-controlled manner using micropumps. In this study, bovine aortic endothelial cells were cultured in the microwells for 48 h and then subjected to fluid shear stress at up to 2 Pa for 6 h. A result showed that realignment and elongation of endothelial cells to the flow direction were dependent on the level of shear stress. It was confirmed that the device could reduce consumption of expensive reagents and precious all samples. Moreover, unlike conventional bulk devices, multiple experimental conditions can be examined at the same time within a single device. It can be concluded that the device has a potential to be applied to multi-purpose single cell tests., The Japan Society of Mechanical Engineers, Japanese

OS1105 Mechanical responses of tenocytes aligned in microgrooves
HAGIWARA Yasuhumi, MAEDA Eijiro, Wang James H-C, OHASHI Toshiro, M&M材料力学カンファレンス, 2011, "OS1105, 1"-"OS1105-2", 16 Jul. 2011
Tendon is subjected to continuous mechanical loading, which imposes cyclic tensile strain and interstitial fluid shear stress to tenocytes. Although a number of studies have characterized mechanical responses of tenocytes to cyclic tensile strain, only few studies have been performed to examine tenocyte responses to fluid shear stress. The present study proposes a newly fabricated cell culture device using MEMS technologies, which enables to apply cyclic tensile strain or fluid shear stress, or both simultaneously, to tenocytes seeded onto microgrooves. It was confirmed that tenocytes exhibited a similar morphology as observed in vivo. Numerical analysis of flow patterns within the device demonstrated that a wide range of fluid shear stress, including a previously predicted physiological value, could be applied to cells. In summary, the present study developed a novel experimental model, which will reveal further details of tenocyte mechanotransduction events., The Japan Society of Mechanical Engineers, Japanese

9J-14 Effect of extracellular matrix on smooth muscle cell phenotype and migration
HAGIWARA Yasufumi, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2010, 23, 583, 584, 07 Jan. 2011
The Japan Society of Mechanical Engineers, Japanese

8H-06 Development of measurement device for traction forces of sheared endothelial cells
TANAKA Ryoichi, SATO Masaaki, OHASHI Toshiro, バイオエンジニアリング講演会講演論文集, 2010, 23, 153, 154, 07 Jan. 2011
The Japan Society of Mechanical Engineers, Japanese

1306 Mechanical Responses of Myofibroblasts to Cyclic Stretch in Wound Healing
OHASHI Toshiro, KOHATA Kengo, M&M材料力学カンファレンス, 2010, 379, 380, 09 Oct. 2010
In this study, it is hypothesized that initial geometrical shapes of cutaneous wound and the major axis of the wound to the direction of stretch could influence myofibroblast realignment observed in the maturation phase of healing process. Firstly, human dermal fibroblasts were differentiated into myofibroblasts with a treatment of TGF-β1. The cells were then seeded onto a PDMS chamber either in a monolayer or in a colony of the following shapes: circle, and track fields both parallel and vertical to the stretch. For mechanical tests, cyclic tensile stretch, with an amplitude of 20%, was pr..., The Japan Society of Mechanical Engineers, Japanese

G0200-3-5 Measurement of ultimate mechanical properties of aortic aneurysm toward rupture risk estimation.
Sugita Shukei, Matsumoto Takeo, Ohashi Toshiro, Kumagai Kiichiro, Akimoto Hiroji, Tabayashi Koichi, Sato Masaaki, The proceedings of the JSME annual meeting, 2010, 5, 51, 52, 04 Sep. 2010
Mechanical properties of the thoracic aortic aneurysm (TAA) tissues were measured in a pressure-imposed test along with histological analysis to estimate their rupture risk. Quadrilateral specimens obtained from TAA were sandwiched with plates having a hole and pressurized from one side of the hole to bulge into the other side until rupture. Intramural stress and strain of each specimen were calculated from its deformation-loading pressure relationship to obtain its ultimate strength and tangent modulus. Histological analysis was then performed to obtain the area fraction of histological co..., The Japan Society of Mechanical Engineers, Japanese

0213 Influence of cyclic stretch on TNF-α production by macrophages
Oya Koki, Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2009, 22, 22, 22, 08 Jan. 2010
The Japan Society of Mechanical Engineers, Japanese

B202 Estimation of Kinesin Density by Analyzing the Time-Course of Changes in the Number of Binding Microtubules
SETOWAKI Sota, SUGITA Shukei, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2009, 20, 95, 96, 06 Nov. 2009
The Japan Society of Mechanical Engineers, Japanese

腰椎牽引療法における椎間板挙動の有限要素法解析
渡辺 祥伍, 大橋 俊朗, 坂元 尚哉, 佐藤 正明, 運動療法と物理療法 = The Journal of physical medicine, 20, 2, 145, 145, 11 Jun. 2009
Japanese

(2)Remodeling of Endothelial Cell Nucleus Exposed to Three Different Mechanical Stimuli
大橋 俊朗, 花村 和彦, 我妻 大策, 坂元 尚哉, 佐藤 正明, Journal of the Japan Society of Mechanical Engineers, 112, 1086, 352, 353, 05 May 2009
The Japan Society of Mechanical Engineers, Japanese

111 Functional response of endothelial cells to high shear stress and high shear stress gradient
Saito Naoki, Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, 講演論文集, 2009, 44, 20, 21, 13 Mar. 2009
The Japan Society of Mechanical Engineers, Japanese

191 Time-lapse observation of change in actin filament structure in endothelial cells exposed to cyclic stretching
HANAMURA Kazuhiko, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2009, 44, 176, 177, 13 Mar. 2009
The Japan Society of Mechanical Engineers, Japanese

192 Observation of actin dynamics in endothelial cells during leukocytes adhesion and migration
ISODA Takumi, UEKI Yousuke, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2009, 44, 178, 179, 13 Mar. 2009
The Japan Society of Mechanical Engineers, Japanese

Morphological Responses of Vascular Endothelial Cells Induced by Local Stretch Transmitted Through Intercellular Junctions
Y. Ueki, N. Sakamoto, T. Ohashi, M. Sato, EXPERIMENTAL MECHANICS, 49, 1, 125, 134, Feb. 2009
English

303 Development of newly designed bioassay system towards single cell analysis
Mori Kiichiroh, Ohashi Toshiro, Lindstrom Sara, Svahn Helene Andersson, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2008, 21, 97, 98, 22 Jan. 2009
The Japan Society of Mechanical Engineers, Japanese

319 Measurement of viscoelastic properties of isolated actin bundles using force-strain dynamic control system
MATSUI Tsubasa, DEGUCHI Shinji, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2008, 21, 129, 130, 22 Jan. 2009
The Japan Society of Mechanical Engineers, Japanese

132 Morphological response of vascular endothelial cells to wall shear stress and the gradient using T-shaped flow chamber
Saito Naoki, Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2008, 21, 293, 294, 22 Jan. 2009
The Japan Society of Mechanical Engineers, Japanese

133 Effect of shear stress and amyloid β on nitric oxide production in endothelial cells
Maruta Toshiyuki, Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2008, 21, 295, 296, 22 Jan. 2009
The Japan Society of Mechanical Engineers, Japanese

134 Effects of cyclic stretch on matrix metalloproteinases production by macrophages
Oya Koki, Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2008, 21, 297, 298, 22 Jan. 2009
The Japan Society of Mechanical Engineers, Japanese

In vitro measurement of viscoelastic properties of actin bundles using micro-tensile tester with visual feedback control　　　　　　　　　　　　　　　
Matsui, T, Deguchi, S, Sakamoto, N, Ohashi, T, Sato, M, 4th Asian Pacific Conference on Biomechanics, 2009

Development of microneedle-based viscoelastic test system for actin bundles　　　　　　　　　　　　　　　
Matsui, T, Deguchi, S, Sakamoto, N, Ohashi, T, Sato, M, 9th International Symposium of Tohoku University Global COE Program, 2009

Shear-stress dependence of changes in morphology and NO production in vascular endothelial cells
OHASHI Toshiro, NAKAMURA Shinji, SAKAMOTO Naoya, SATO Masaaki, 運動療法と物理療法 = The Journal of physical medicine, 19, 3, 176, 183, 30 Nov. 2008
Japanese

4・2・1 細胞のバイオメカニクス(4・2 バイオメカニカルエンジニアリング,4.バイオエンジニアリング,<特集>機械工学年鑑)
大橋 俊朗, 日本機械学會誌, 111, 1077, 650, 650, 05 Aug. 2008
一般社団法人日本機械学会, Japanese

4・3・1 バイオマテリアル(4・3 バイオメディカルエンジニアリング・ライフサポート工学,4.バイオエンジニアリング,<特集>機械工学年鑑)
田中 英一, 大橋 俊朗, 大島 まり, 田中 英一, 田中 志信, 川野 聡恭, 日本機械学會誌, 111, 1077, 650, 651, 05 Aug. 2008
一般社団法人日本機械学会, Japanese

533 Construction of algorithm for motion analysis of kinesin-driven microtubules towards development of micro-transport devices
SUGITA Shukei, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, The proceedings of the JSME annual meeting, 2008, 8, 265, 266, 02 Aug. 2008
Microtubules (MTs) gliding on the kinesin-coated surface in vitro have a good feasibility for development of micro-scale transport systems. The key requirements in the development of the system include an image analysis to detect and recognize gliding MTs. In this study, we present an algorithm for detecting the position of the leading tips of gliding MTs. The algorithm operates on binarized fluorescent images of MTs and extracts the tips of MTs with a kernel. For verification, the algorithm was applied to a sample segment, and the distance between extracted coordinates with the algorithm a..., The Japan Society of Mechanical Engineers, Japanese

Observation of dynamic behavior of VE-cadherins in endothelial cells exposed to shear stress
SAKAMOTO Naoya, SEGAWA Kei, OHASHI Toshiro, SATO Masaaki, Transactions of Visualization Society of Japan, 28, 1, 323, 324, 01 Jul. 2008
The Visualization Society of Japan, Japanese

(2)Newly Designed Tensile Test System for in vitro Measurement of Mechanical Properties of Cytoskeletal Filaments
出口 真次, 大橋 俊朗, 佐藤 正明, Journal of the Japan Society of Mechanical Engineers, 111, 1074, 372, 373, 05 May 2008
The Japan Society of Mechanical Engineers, Japanese

Study of intracellular stress transfer using microfabricated substrate
大橋 俊朗, Reports of Toyoda Physical and Chemical Research Institute., 61, 131, 135, May 2008
豊田理化学研究所, Japanese

DP-109-4 有限要素法を用いた胸部大動脈瘤の応力解析と破断予測(第108回日本外科学会定期学術集会)
熊谷 紀一郎, 本吉 直孝, 田林 晄一, 大橋 俊朗, 佐藤 正明, 日本外科学会雑誌, 109, 2, 562, 562, 25 Apr. 2008
一般社団法人日本外科学会, Japanese

Periodontal tissue activation by vibration: Intermittent stimulation by resonance vibration accelerates experimental tooth movement in rats
Makoto Nishimura, Mirei Chiba, Toshiro Ohashi, Masaaki Sato, Yoshiyuki Shimizu, Kaoru Igarashi, Hideo Mitani, AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS, 133, 4, 572, 583, Apr. 2008
English

地球温暖化と雪明り(リレー随筆)
大橋 俊朗, 生体医工学 : 日本エム・イー学会誌, 46, 1, 127, 127, 10 Feb. 2008
社団法人日本生体医工学会, Japanese

316 FRAP Analysis of Actin Dynamics of Smooth Muscle Cells Exposed to Cyclic Stretch
Ito Kazushi, HANAMURA Kazuhiko, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 109, 110, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

314 Effect of actin-myosin interaction on stress relaxation behavior of isolated stress fibers
MATSUI Tsubasa, DEGUCHI Shinji, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 105, 106, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

307 Effect of shear stress on matrix metalloproteinases expression in endothelial cells
Sakamoto Naoya, Mochimaru Takato, Ohashi Toshiro, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 91, 92, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

306 Construction of co-cultured blood vessel model using phenotype-controlled smooth muscle cells
KIUCHI Takuya, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 89, 90, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

327 Dynamic control of direction of kinesin-driven microtubules utilizing electric fields
SUGITA Shukei, SETOWAKI Sota, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 317, 318, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

326 Basic Study of Microtubule Sorting by Length Using Kinesin-Coated Microstructure
MURASE Tatsuya, SUGITA Shukei, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 315, 316, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

323 Effect of different types of extracellular matrix on cellular traction forces
ICHIHARA Hirokazu, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2007, 20, 309, 310, 24 Jan. 2008
The Japan Society of Mechanical Engineers, Japanese

Remodeling of endothelial cells induced by tension transmitted through intercellular junctions
Y. Ueki, N. Sakamoto, T. Ohashi, M. Sato, BIORHEOLOGY, 45, 1-2, 96, 96, 2008
English, Summary international conference

Influence of fluid shear stress on matrix metalloproteinase production in endothelial cells
N. Sakamoto, T. Ohashi, M. Sato, The 13th International Conference on Biomedical Engineering, 2008

In vitro viscoelastic test apparatus for cytoskeletal bundles　　　　　　　　　　　　　　　
Matsui, T, Deguchi, S, Sakamoto, N, Ohashi, T, Sato, M, Proceedings of GPBE/NUS-Tohoku Graduate Student Conference in Bioengineering, 2008

A dynamic force-strain control system for isolated actin bundles　　　　　　　　　　　　　　　
Matsui, T, Deguchi, S, Sakamoto, N, Ohashi, T, Sato, M, Proceedings of Tohoku-NUS Student Joint Symposium, 2008

Intercellular junctions-mediated morphological responses of vascular endothelial cells induced by local stretch　　　　　　　　　　　　　　　
Experimental Mechanics, 2008

Intercellular junctions-mediated morphological responses of vascular endothelial cells induced by local stretch　　　　　　　　　　　　　　　
Experimental Mechanics, 2008

1011 Change in Elastic Modulus and Actin Dynamics of Chondrocytes Exposed to Local Mechanical Stimulation
OHASHI Toshiro, KURODA Ryosuke, Knight Martin, Bader Dan, SATO Masaaki, The proceedings of the JSME annual meeting, 2007, 5, 223, 224, 07 Sep. 2007
Articular chondrocytes in vivo are continuously exposed to severe mechanical conditions and are supposed to exhibit reorganization of cytoskeletons, possibly altering mechanical properties of cells. In this study, the effect of local deformation on mechanical properties of chondrocytes was investigated using a micropipette aspiration technique, particularly focusing on actin remodeling. Repeat aspiration experiments showed that change in the Young's modulus of chondrocytes significantly depends on the aspiration rate. Ca^<2+> blocking experiments revealed that local deformation induces Ca^<..., The Japan Society of Mechanical Engineers, Japanese

Trial of new vascular clips for aortic anastomosis in a canine model
Shinya Masuda, Yoshikatsu Saiki, Satoshi Kawatsu, Ichiro Yoshioka, Hidenori Fujiwara, Shunsuke Kawamoto, Sadahiro Sai, Atsushi Iguchi, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato, Koichi Tabayashi, JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY, 134, 3, 723, 730, Sep. 2007
English

Trial of new vascular clips for aortic anastomosis in a canine model
Shinya Masuda, Yoshikatsu Saiki, Satoshi Kawatsu, Ichiro Yoshioka, Hidenori Fujiwara, Shunsuke Kawamoto, Sadahiro Sai, Atsushi Iguchi, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato, Koichi Tabayashi, Journal of Thoracic and Cardiovascular Surgery, 134, 3, 723, 730, Sep. 2007
English

S-31. 平滑筋細胞の牽引力計測と骨格構造の力学的役割(血管平滑筋研究の新展開, 第49回日本平滑筋学会総会)
大橋 俊朗, 亀田 憲史, 佐藤 正明, 日本平滑筋学会雑誌, 11, 1, "J, 21", 26 Jun. 2007
日本平滑筋学会, Japanese

第46回日本生体医工学会大会報告(学会紹介)
大橋 俊朗, 生体医工学 : 日本エム・イー学会誌, 45, 2, 186, 187, 10 Jun. 2007
社団法人日本生体医工学会, Japanese

腰椎牽引時に作用する荷重分布および腰椎挙動に関する数値解析
大橋 俊朗, 黄 文敬, 坂元 尚哉, 佐藤 正明, 運動療法と物理療法 = The Journal of physical medicine, 18, 2, 89, 89, 07 Jun. 2007
Japanese

Microelastic mapping of living endothelial cells exposed to shear stress in relation to three-dimensional distribution of actin filaments
Masaaki Sato, Kenichi Suzuki, Yosuke Ueki, Toshiro Ohashi, ACTA BIOMATERIALIA, 3, 3, 311, 319, May 2007
English

218 Change in cytoskeletal structure of vascular endothelial cells induced by mechanical stimulation at intercellular junctions
UEKI Yosuke, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2006, 19, 46, 47, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese

603 Functional role of VE-cadherin in morphological changes of flow-exposed endothelial cells
SEGAWA Kei, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2006, 19, 202, 203, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese

435 Actin dynamics in smooth muscle cells in response to mechanical stimulation using FRAP technique
Ito Kazushi, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2006, 19, 370, 371, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese

436 Estimation of stress balance in smooth muscle cells by traction force measurements
NAKAMURA Shouji, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2006, 19, 372, 373, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese

443 Effect of local mechanical stimulation on actin remodeling of chondrocytes
KURODA Ryosuke, OHASHI Toshiro, Knight Martin, Bader Dan, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2006, 19, 386, 387, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese

444 Remodeling in endothelial cells exposed to cyclic stretching using microfabricated membranes
YAMAZAKI Yoshimasa, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2006, 19, 388, 389, 06 Jan. 2007
The Japan Society of Mechanical Engineers, Japanese

Effect of fluid shear stress on smooth muscle cell migration and permeability of endothelial monolayer in endothelial-smooth muscle cells cocultured model　　　　　　　　　　　　　　　
N. Sakamoto, T. Ohashi, M. Sato, Proceedings of the Final Symposium of the Tohoku University 21st Century Center of Excellence Program, 163, 172, 2007

Mechanical properties of subcellular structural components isolated from cultured vascular cells　　　　　　　　　　　　　　　
S Deguchi, T Ohashi, M Sato, Proc. 9th International Symposium of Future Medical Engineering Based on Bio-nanotechnology, 2007

Stress-relaxation properties of stress fibers isolated from smooth muscle cells　　　　　　　　　　　　　　　
Matsui, T, Deguchi, S, Sakamoto, N, Ohashi, T, Sato, M, Proceedings of 9th International Symposium of Future Medical Engineering Based on Bio-nanotechnology, 2007

Modifying anastomotic site in thoracic aortic surgery by using biodegradable felt strips with or without basic fibroblast growth factor　　　　　　　　　　　　　　　
H. Fujiwara, Y. Saiki, K. Oda, S. Kawatsu, I. Yoshioka, N. Sakamoto, T. Ohashi, M. Sato, Y. Tabata, K. Tabayashi, The 8th Annual International Symposium on Advances in Understanding Aortic Diseases（ 2007.10.13－14．Tokyo）, 2007, [Peer-reviewed]
English

Influence of Pulsatile Flow on Integrin Expression and Morphology of Vascular Endothelial Cells　　　　　　　　　　　　　　　
Technology and Health Care, 15, 91, 101, 2007

Effect of Mechanical Environment of Focal Adhesions on Remodeling of Endothelial Cells Subjected to Cyclic Stretch Using Microstructured Substrate　　　　　　　　　　　　　　　
Journal of Robotics and Mechatronics, 2007

Nonuniform strain of substrate induces local development of stress fibers in endothelial cells under uniaxial cyclic stretching
Toshiro Ohashi, Masanori Masuda, Takeo Matsumoto, Masaaki Sato, CLINICAL HEMORHEOLOGY AND MICROCIRCULATION, 37, 1-2, 37, 46, 2007
English

Hydrostatic Pressure Influences Morphology and Expression of VE-Cadherin of Vascular Endothelial Cells
Journal of Biomechanics, 2007

Estimation of Mechanical Role of Intracellular Cellular Structures in Smooth Muscle Cells by Using Traction Force Measurements　　　　　　　　　　　　　　　
Proceedings of The 11th International Conference on Miniaturized Systems for Chemistry and Life Sciences, 2007

Influence of Pulsatile Flow on Integrin Expression and Morphology of Vascular Endothelial Cells　　　　　　　　　　　　　　　
Technology and Health Care, 15, 91, 101, 2007

Effects of Frequency of Pulsatile Flow on Morphology and Integrin Expression of Vascular Endothelial Cells　　　　　　　　　　　　　　　
Technology and Health Care, 15, 91, 101, 2007

Adhesive Force of Human Hepatoma HepG2 Cells to Endothelial Cells and Expression of E-selectin　　　　　　　　　　　　　　　
Molecular & Cellular Biomechanics, 2007

Estimation of Mechanical Role of Intracellular Cellular Structures in Smooth Muscle Cells by Using Traction Force Measurements　　　　　　　　　　　　　　　
Proceedings of The 11th International Conference on Miniaturized Systems for Chemistry and Life Sciences, 2007

Effects of Frequency of Pulsatile Flow on Morphology and Integrin Expression of Vascular Endothelial Cells　　　　　　　　　　　　　　　
Technology and Health Care, 15, 91, 101, 2007

Effect of Mechanical Environment of Focal Adhesions on Remodeling of Endothelial Cells Subjected to Cyclic Stretch Using Microstructured Substrate　　　　　　　　　　　　　　　
Journal of Robotics and Mechatronics, 2007

Hydrostatic pressure influences morphology and expression of VE-cadherin of vascular endothelial cells
Toshiro Ohashi, Yoshiaki Sugaya, Naoya Sakamoto, Masaaki Sato, JOURNAL OF BIOMECHANICS, 40, 11, 2399, 2405, 2007
English

Adhesive Force of Human Hepatoma HepG2 Cells to Endothelial Cells and Expression of E-selectin　　　　　　　　　　　　　　　
Molecular & Cellular Biomechanics, 2007

Fractographic Analysis on Root Fracture of Tooth by Analyzing Three-dimensional Structure Constructed from SEM Image : Cases of Fractured Teeth after Prosthetic Treatment
MATSUI Tsubasa, OHASHI Toshiro, ENDO Hideaki, SASAKI Tomohumi, ITO Hidemi, SATO Masaaki, Journal of JSEM, 6, 4, 423, 427, 25 Dec. 2006
日本実験力学会, Japanese

S2e2-3 Effects of Hydrostatic Pressure on Morphology of Cultured Bovine Aortic Endothelial Cells(S2-e2: "Nano-scale Mechanobiology of Cells",Symposia,Abstract,Meeting Program of EABS & BSJ 2006)
Sato Masaaki, Sugaya Yoshiaki, Sakamoto Naoya, Ohashi Toshiro, Biophysics, 46, 2, S131, 01 Oct. 2006
The Biophysical Society of Japan, English

Prediction of Stress Distribution in Mandibular Bone Treated with Distal-Extension Partial Denture Using Finite Element Analysis
OHASHI Toshiro, SATO Yoshikazu, SASAKI Tomofumi, ITOH Hidemi, SATO Masaaki, Journal of JSEM, 6, 3, 269, 274, 25 Sep. 2006
This paper describes the feasibility of using finite element analysis to predict stress distributions in mandibular bone treated with a distal-extension partial denture, compared with conventional photoelastic method. A finite element model was constructed based on the CT scan data of the three-dimensional photoelastic model, which was anatomically realistic replica of a patient mandibular bone with teeth. A vertical loading was applied to a specially designed metal pyramid mounted on the first molar region to mimic functional movements of the partial denture. The numerical results showed that higher stress was observed in the apical and distal sides of the abutment teeth, which was the similar tendency to the experimental results obtained by the photoelastic method. Moreover, stress distributions depended on the variety of loadings applied to the different point of the pyramid. The present analysis may give a better prediction of stress distributions in patient mandibular bone than the photoelastic method., The Japanese Society for Experimental Mechanics, English

713 Tensile Properties and Local Strain Distribution of Isolated Stress Fibers
MATSUI Tsubasa, OHASHI Toshiro, DEGUCHI Shinji, SATO Masaaki, The proceedings of the JSME annual meeting, 2006, 5, 227, 228, 15 Sep. 2006
In our previous study, tensile properties of single stress fibers (SF) chemically isolated from vascular smooth muscle cells have been investigated. Tensile tests were performed at a single strain rate of 0.02s^<-1>. In this study, the strain rate dependency of tensile properties of SF was investigated. The results showed that averaged force-strain relationships were found to be almost linear in the physio-logical strain range of 0.0-0.4 for 0.01s^<-1> and 0.05s^<-1>. In contrast, the force-strain relationship was nonlinear for the 0.1s^<-1> strain rate. The reason for this difference is un..., The Japan Society of Mechanical Engineers, Japanese

735 Control of Cell Morphology and Measurement of Traction Forces of Smooth Muscle Cells Using Microfabricated Devices
OHASHI Toshiro, YAMAZAKI Junichi, SATO Masaaki, The proceedings of the JSME annual meeting, 2006, 5, 269, 270, 15 Sep. 2006
Although cellular traction forces are believed to play an important role in the interactions between cells and their substrates, little is known of the effect of mechanical environment on the magnitude and direction of traction forces and hence how intracellular structures contribute to traction forces. In this study, microfabricated substrates, array of micropillars with different spacing, were used to estimate cellular traction forces of smooth muscle cells, particularly exploring the contribution of microtubules to traction forces. A significant increase in traction forces from 15.2±1.4 ..., The Japan Society of Mechanical Engineers, Japanese

Effect of Hydrostatic Pressure on the Morphology and Expression of VE-Cadherin in HUVEC
OHASHI Toshiro, SEGAWA Kei, SAKAMOTO Naoya, SATO Masaaki, Transactions of the Japanese Society for Medical and Biological Engineering : BME, 44, 3, 454, 459, 10 Sep. 2006
To study endothelial cell remodeling in response to hydrostatic pressure, human umbilical vein endothelial cells (HUVECs) were exposed to hydrostatic pressure of 25 and 100 mmHg and changes in morphology and expression of VE-cadherin were studied. After exposure to hydrostatic pressure, HUVECs exhibited elongated and tortuous shape without predominant orientation, together with development of centrally located, thick stress fibers. Particularly, HUVEs exposed to 25 mmHg exhibited more tortuous shape compared to those both under control conditions and 100 mmHg. HUVECs did not exhibit a multi..., Japanese Society for Medical and Biological Engineering, Japanese

Recent advances in cell biomechanics
大橋 俊朗, B & R, 20, 3, 110, 112, Sep. 2006
日本バイオレオロジ-学会, Japanese

16.拍動流を負荷した血管内皮細胞でのインテグリン発現の変化(平成17年度東北支部大会抄録)
伊藤 一志, 坂元 尚哉, 大橋 俊朗, 佐藤 正明, 生体医工学 : 日本エム・イー学会誌, 44, 2, 319, 319, 10 Jun. 2006
社団法人日本生体医工学会, Japanese

Finite Element Analysis of Teeth Treated with Partial Denture for Evaluating Root Fracture
YAMAZAKI Yoshimasa, SASAKI Tomohumi, ITO Hidemi, OHASHI Toshiro, SATO Masaaki, Journal of JSEM, 6, 1, 19, 23, 25 Mar. 2006
日本実験力学会, Japanese

322 Tensile Properties of Isolated Stress Fibers Depend on Strain Rate
MATSUI Tsubasa, DEGUCHI Shinji, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2006, 41, 145, 146, 14 Mar. 2006
The Japan Society of Mechanical Engineers, Japanese

323 Control of morphology and measurement of traction forces of smooth muscle cells using microfabricated matrix device
YAMAZAKI Junichi, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2006, 41, 147, 148, 14 Mar. 2006
The Japan Society of Mechanical Engineers, Japanese

501 Mechanical adaptation and phenotypic transformation of chondrocytes exposed to hydrostatic pressure
IDO Hideto, KURODA Ryosuke, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2006, 41, 193, 194, 14 Mar. 2006
The Japan Society of Mechanical Engineers, Japanese

503 Measurement of mechanical properties and finite element analysis of human thoracic aortic aneurysm
USHIYAMA Takatomo, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2006, 41, 197, 198, 14 Mar. 2006
The Japan Society of Mechanical Engineers, Japanese

Effect of fluid shear stress on migration of vascular smooth muscle cells in cocultured model
Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato, Annals of Biomedical Engineering, 34, 3, 408, 415, Mar. 2006
English

The wrapping method using biodegradable felt strips has a preventive effect on the thinning of the aortic wall: Experimental study in the canine aorta
H Fujiwara, K Oda, Y Saiki, N Sakamoto, T Ohashi, M Sato, Y Tabata, K Tabayashi, JOURNAL OF VASCULAR SURGERY, 43, 2, 349, 356, Feb. 2006
English

The wrapping method using biodegradable felt strips has a preventive effect on the thinning of the aortic wall: Experimental study in the canine aorta
Hidenori Fujiwara, Katsuhiko Oda, Yoshikatsu Saiki, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato, Yasuhiko Tabata, Koichi Tabayashi, Journal of Vascular Surgery, 43, 2, 349, 356, Feb. 2006
English

117 The Effect of Strain Rate on Tensile Properties of Isolated Stress Fibers
MATSUI Tsubasa, DEGUCHI Shinji, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2005, 18, 41, 42, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese

118 Mechanical role of cytoskeletal structures in traction forces in smooth muscle cells
OHASHI Toshiro, KAMEDA Norifumi, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2005, 18, 43, 44, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese

124 Effect of hydrostatic pressure on mechanical properties and phenotype of articular chondrocytes
IDO Hideto, KURODA Ryosuke, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2005, 18, 55, 56, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese

337 Change in production of nitric oxide in EC-SMC cocultured model
OI Masaki, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2005, 18, 211, 212, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese

340 Measurement of adhesion properties and proliferation of smooth muscle cell using microfabricated matrix device
YAMAZAKI Junichi, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2005, 18, 217, 218, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese

432 Mechanical properties and histology of human thoracic aortic aneurysms
USHIYAMA Takatomo, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2005, 18, 283, 284, 12 Jan. 2006
The Japan Society of Mechanical Engineers, Japanese

"Flow-induced hardening of endothelial nucleus ... " by Deguchi et al. Author's response
S Deguchi, K Maeda, T Ohashi, M Sato, JOURNAL OF BIOMECHANICS, 39, 7, 1362, 1362, 2006
English, Report scientific journal

Intracellular force balance in actin stress fiber network　　　　　　　　　　　　　　　
S Deguchi, T Ohashi, M Sato, Proc. 5th World Congress of Biomechanics, 2006

Biomechanical properties and roles of stress fibers in mechanotransduction　　　　　　　　　　　　　　　
M Sato, S Deguchi, T Matsui, T Ohashi, Proc. 5th World Congress of Biomechanics, 2006

Viscoelastic properties and locally heterogeneous deformation of stress fibers isolated from smooth muscle cells　　　　　　　　　　　　　　　
Matsui, T, Deguchi, S, Sakamoto, N, Ohashi, T, Sato, M, Proceedings of the 2nd Tohoku-NUS Joint Symposium on the Future Nano-medicine and Bioengineering in the East Asian Region, 2006

Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells
Shinji Deguchi, Toshiro Ohashi, Masaaki Sato, JOURNAL OF BIOMECHANICS, 39, 14, 2603, 2610, 2006
English

Evaluation of tension in actin bundle of endothelial cells based on preexisting strain and tensile properties measurements　　　　　　　　　　　　　　　
Molecular & Cellular Biomechanics, 2006

Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells
Shinji Deguchi, Toshiro Ohashi, Masaaki Sato, Journal of Biomechanics, 39, 14, 2603, 2610, 2006
English

Intracellular stress transmission through actin stress fiber network in adherent vascular cells　　　　　　　　　　　　　　　
Molecular & Cellular Biomechanics, 2006

Intracellular mechanics and mechanotransduction associated with chondrocyte deformation during pipette aspiration
T. Ohashi, M. Hagiwara, D. L. Bader, M. M. Knight, BIORHEOLOGY, 43, 3-4, 201, 214, 2006
English

Transendothelial Migration of Leukocytes in Cocultured Vessel Model Exposed to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the BMES Annual Fall Meeting, 2006

Effect of fluid shear stress on migration of vascular smooth muscle cells in cocultured model
Annals of Biomedical Engineering, 34, 3, 408, 415, 2006

細胞バイオメカニクスにおける近年の進歩　　　　　　　　　　　　　　　
日本バイオレオロジー学会誌, 20, 3, 12, 14, 2006

Evaluation of tension in actin bundle of endothelial cells based on preexisting strain and tensile properties measurements　　　　　　　　　　　　　　　
Molecular & Cellular Biomechanics, 2006

Effect of Fluid Shear Stress on Migration of Vascular Smooth Muscle Cells in Cocultured Model
SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, Annals of Biomedical Engineering, 34, 3, 408, 415, 2006

Nitric Oxide Production and Smooth Muscle Cell Phenotype of Endothelial Cell-Smooth Muscle Cell Cocultured Model
SAKAMOTO Naoya, OI Masaki, OHASHI Toshiro, SATO Masaaki, JBSE, 1, 1, 224, 233, 2006
This study investigated nitric oxide (NO) production and phenotype changes of smooth muscle cells (SMC) in a cocultured model (CM) exposed to fluid shear stress. The CM was composed of human umbilical endothelial cells (EC) and SMC, a collagen layer, and a porous membrane. After exposing the CM to shear stress of 1.5 Pa for 24 hours, α-smooth muscle actin (α-SMA) expression of SMC and NO production in culture media were examined. Under static conditions, α-SMA expression in the CM was significantly lower than that of a SMC monocultured model (SMC model). After exposure to shear stress, NO production in the CM increased compared to that in the static CM, and there was no significant difference in α-SMA expression between the CM and SMC model. These results suggest that EC may regulate phenotype changes of cocultured SMC, and NO may be one of the factors which induce dedifferentiation of SMC., The Japan Society of Mechanical Engineers, English

Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells
Shinji Deguchi, Toshiro Ohashi, Masaaki Sato, Journal of Biomechanics, 39, 14, 2603, 2610, 2006
English

Intracellular stress transmission through actin stress fiber network in adherent vascular cells　　　　　　　　　　　　　　　
Molecular & Cellular Biomechanics, 2006

SEM像立体解析による歯根破折の破壊力学的検討　　　　　　　　　　　　　　　
日本実験力学会誌, 6, 4, 77, 81, 2006

Nitric Oxide Production and Smooth Muscle Cell Phenotype of Endothelial Cell-Smooth Muscle Cell Cocultured Model
SAKAMOTO Naoya, OI Masaki, OHASHI Toshiro, SATO Masaaki, Journal of Biomechanical Science and Engineering, 1, 1, 224, 233, 2006
This study investigated nitric oxide (NO) production and phenotype changes of smooth muscle cells (SMC) in a cocultured model (CM) exposed to fluid shear stress. The CM was composed of human umbilical endothelial cells (EC) and SMC, a collagen layer, and a porous membrane. After exposing the CM to shear stress of 1.5 Pa for 24 hours, α-smooth muscle actin (α-SMA) expression of SMC and NO production in culture media were examined. Under static conditions, α-SMA expression in the CM was significantly lower than that of a SMC monocultured model (SMC model). After exposure to shear stress, NO production in the CM increased compared to that in the static CM, and there was no significant difference in α-SMA expression between the CM and SMC model. These results suggest that EC may regulate phenotype changes of cocultured SMC, and NO may be one of the factors which induce dedifferentiation of SMC., The Japan Society of Mechanical Engineers, English

Transendothelial Migration of Leukocytes in Cocultured Vessel Model Exposed to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the BMES Annual Fall Meeting, 2006

バイオメカニクス
大橋 俊朗, 人工臓器, 34, 3, 184, 186, 15 Dec. 2005
一般社団法人 日本人工臓器学会, Japanese

Intracellular stress transmission through actin stress fiber network in adherent vascular cells
S. Deguchi, T. Ohashi, M. Sato, MCB Molecular and Cellular Biomechanics, 2, 4, 205, 216, Dec. 2005
English

拍動周期が内皮細胞のインテグリン発現に及ぼす影響 (〔平成17年度日本バイオレオロジー学会〕論文賞および奨励賞受賞講演論文)
伊藤 一志, 坂元 尚哉, 大橋 俊朗, 日本バイオレオロジ-学会誌, 19, 4, 164, 168, Dec. 2005
日本バイオレオロジ-学会, Japanese

Newly designed tensile test system for in vitro measurement of mechanical properties of cytoskeletal filaments
S Deguchi, T Ohashi, M Sato, JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 48, 4, 396, 402, Dec. 2005
English

A101 Effect of Cellular Interactions on Transendothelial Migration of Leukocytes Using Cocultured Vessel Model Exposed to Shear Stress
UEKI Yosuke, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2005, 16, 1, 2, 08 Nov. 2005
The Japan Society of Mechanical Engineers, Japanese

A102 Effect of Pulsatile Flow on Integrin Expression of Endothelial Cells
Ito Kazushi, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2005, 16, 3, 4, 08 Nov. 2005
The Japan Society of Mechanical Engineers, Japanese

A103 The effect of hydrostatic pressure on mechanical properties and collagen production in cultured articular chondrocyte
KURODA Ryosuke, IDO Hideto, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2005, 16, 5, 6, 08 Nov. 2005
The Japan Society of Mechanical Engineers, Japanese

Pipette aspiration technique for the measurement of nonlinear and anisotropic mechanical properties of blood vessel walls under biaxial stretch
T Ohashi, H Abe, T Matsumoto, M Sato, JOURNAL OF BIOMECHANICS, 38, 11, 2248, 2256, Nov. 2005
English

1251 Role of Cytoskeleton and Focal Adhesion in Sheared Endothelial Cells
OHASHI Toshiro, KUMAGAI Yoshiharu, MOCHIZUKI Naoki, SATO Masaaki, The proceedings of the JSME annual meeting, 2005, 6, 113, 114, 18 Sep. 2005
Temporal behavior of cytoskeletons such as actin filaments, and microtubules and FAT (Focal Adhesion Targeting) domain was observed in sheared endothelial cells using gene transfection technique to understand their mechanical roles in endothelial cell remodeling. Plasmid encoding enhanced GFP-actin, GFP-tubulin and RFP-FAT domain were transfected into bovine aortic endothelial cells using a liposomal method. After gene transfection, cells were exposed to shear stress of 2 Pa using a parallel plate flow chamber and temporally observed by fluorescence microscopy. During the process of cell el..., The Japan Society of Mechanical Engineers, Japanese

113 Endothelial cell remodeling in response to fluid shear stress
OHASHI Toshiro, 日本機械学会東北支部秋季講演会講演論文集, 2005, 41, 29, 30, 09 Sep. 2005
The Japan Society of Mechanical Engineers, Japanese

Evaluation of tension in actin bundle of endothelial cells based on preexisting strain and tensile properties measurements
S. Deguchi, T. Ohashi, M. Sato, MCB Molecular and Cellular Biomechanics, 2, 3, 125, 133, Sep. 2005
English

Flow-induced hardening of endothelial nucleus as an intracellular stress-bearing organelle
S Deguchi, K Maeda, T Ohashi, M Sato, JOURNAL OF BIOMECHANICS, 38, 9, 1751, 1759, Sep. 2005
English

Remodeling of vascular endothelial cells exposed to fluid shear stress: Experimental and numerical approach
Toshiro Ohashi, Masaaki Sato, Fluid Dynamics Research, 37, 1-2, 40, 59, Jul. 2005
English, Book review

Remodeling of vascular endothelial cells exposed to fluid shear stress: experimental and numerical approach
T Ohashi, M Sato, FLUID DYNAMICS RESEARCH, 37, 1-2, 40, 59, Jul. 2005
English

拍動周期が内皮細胞のインテグリン発現に及ぼす影響
伊藤 一志, 坂元 尚哉, 大橋 俊朗, 佐藤 正明, 日本バイオレオロジー学会年会抄録集, 28, 26, 26, 30 Jun. 2005
Japanese

共存培養モデルにおけるせん断応力負荷内皮細胞と白血球の接着性変化
大井 正樹, 坂元 尚哉, 大橋 俊朗, 佐藤 正明, 日本バイオレオロジー学会年会抄録集, 28, 38, 38, 30 Jun. 2005
Japanese

マイクロポストを用いた平滑筋細胞の牽引力計測
大橋 俊朗, 亀田 憲史, 佐藤 正明, 日本バイオレオロジー学会年会抄録集, 28, 44, 44, 30 Jun. 2005
Japanese

静水圧が培養内皮細胞の形態およびカドヘリン発現に与える影響
佐藤 正明, 菅谷 嘉晃, 坂元 尚哉, 大橋 俊朗, 日本バイオレオロジー学会年会抄録集, 28, 52, 52, 30 Jun. 2005
Japanese

08. せん断応力を負荷した共存培養モデルの内皮細胞に対する白血球接着性の変化(平成16年度東北支部大会抄録, 支部大会抄録)
大井 正樹, 坂元 尚哉, 大橋 俊朗, 佐藤 正明, 生体医工学 : 日本エム・イー学会誌, 43, 2, 328, 329, 10 Jun. 2005
社団法人日本生体医工学会, Japanese

09. コンドロサイトの力学特性とコラーゲンの産生に対する静水圧の影響(平成16年度東北支部大会抄録, 支部大会抄録)
井戸 秀人, 黒田 亮典, 大橋 俊朗, 佐藤 正明, 生体医工学 : 日本エム・イー学会誌, 43, 2, 329, 329, 10 Jun. 2005
社団法人日本生体医工学会, Japanese

111 Temporal Observation of Changes in Cytoskeletal Structure and Focal Adhesions in Cultured Endothelial Cells Exposed to Fluid Flow
KUMAGAI Yoshiharu, OHASHI Toshiro, MOCHIZUKI Naoki, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2004, 17, 23, 24, 21 Jan. 2005
The Japan Society of Mechanical Engineers, Japanese

132 Effect of Periods of Pulsatile Flow on Cell-Matrix Adhesion of Cultured Endothelial Cells
Ito Kazushi, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2004, 17, 259, 260, 21 Jan. 2005
The Japan Society of Mechanical Engineers, Japanese

Mechanical properties of isolated stress fibers and nuclei to understand mechanical responses of endothelial cells　　　　　　　　　　　　　　　
M Sato, S Deguchi, T Ohashi, Proc. 6th Asian-Pacific Conference on Medical and Biological Engineering, 2005

Mechanical properties of stress fiber and nucleus to understand intracellular stress transmission　　　　　　　　　　　　　　　
S Deguchi, T Ohashi, M Sato, Proc. The Second Japan-Switzerland Workshop on Biomechanics, 2005

In vivo mechanical properties of thoracic aortic aneurysmal wall estimated from in vitro biaxial tensile test
T Fukui, T Matsumoto, T Tanaka, T Ohashi, K Kumagai, H Akimoto, K Tabayashi, M Sato, BIO-MEDICAL MATERIALS AND ENGINEERING, 15, 4, 295, 305, 2005
English

Multilayered Phenomena of Cultured Bovine Aortic Endothelial Cells by Exposure to Hydrostatic Pressure　　　　　　　　　　　　　　　
Proceedings of the International Federation for Medical and Biological Engineering, 2005

Subcellular Distribution of Traction Forces of Smooth Muscle Cells Using Micropatterned Substrates　　　　　　　　　　　　　　　
Proceedings of the 12th International Congress of Biorheology, 2005

Multilayered Phenomena of Cultured Bovine Aortic Endothelial Cells by Exposure to Hydrostatic Pressure　　　　　　　　　　　　　　　
Proceedings of the International Federation for Medical and Biological Engineering, 2005

Adhesive Property of Leukocytes to Endothelial Cells in Cocultured Model Exposed to Fluid Shear Stress　　　　　　　　　　　　　　　
Proceedings of the ASME 2005 Summer Bioengineering Conference, 2005

Tensile properties of single stress fibers characterized by in vitro manipulation
BIORHEOLOGY, 42, 1-2, 37, 38, 2005
English, Summary international conference

Contributions of Cytoskeletal Structures to Traction Forces Generated by Smooth Muscle Cells Using Microfabricated Substrate　　　　　　　　　　　　　　　
Proceedings of the International Federation for Medical and Biological Engineering, 2005

Tensile Properties of Single Stress Fibers Characterized by In Vitro Manipulation　　　　　　　　　　　　　　　
Proceedings of the 12th International Congress of Biorheology, 2005

Subcellular Distribution of Traction Forces of Smooth Muscle Cells Using Micropatterned Substrates　　　　　　　　　　　　　　　
Proceedings of the 12th International Congress of Biorheology, 2005

Biorheological views of endothelial cell responses to mechanical stimuli
M Sato, T Ohashi, BIORHEOLOGY, 42, 6, 421, 441, 2005
English

Tensile Properties of Single Stress Fibers Isolated from Cultured Vascular Smooth Muscle Cells
Journal of Biomechanics, 39, 14, 2603, 2610, 2005

Biorheological Views of Endothelial Cell Responses to Mechanical Stimuli　　　　　　　　　　　　　　　
Biorheology, 42, 6, 421, 441, 2005

Contributions of Cytoskeletal Structures to Traction Forces Generated by Smooth Muscle Cells Using Microfabricated Substrate　　　　　　　　　　　　　　　
Proceedings of the International Federation for Medical and Biological Engineering, 2005

Adhesive Property of Leukocytes to Endothelial Cells in Cocultured Model Exposed to Fluid Shear Stress　　　　　　　　　　　　　　　
Proceedings of the ASME 2005 Summer Bioengineering Conference, 2005

Effect of shear stress on permeability of vascular endothelial monolayer cocultured with smooth muscle cells
N Sakamoto, T Ohashi, M Sato, JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 47, 4, 992, 999, Dec. 2004
English

Effect of hydrostatic pressure on mechanical properties and collagen production of articular chondrocyte
IDO Hideto, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2004, 15, 17, 18, 04 Nov. 2004
The Japan Society of Mechanical Engineers, Japanese

The effect of shear stress on adhesion properties of leukocytes to endothelial cells in cocultured model
OI Masaki, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2004, 15, 21, 22, 04 Nov. 2004
The Japan Society of Mechanical Engineers, Japanese

Finite Element Analysis for Sheared Vascular Endothelial Cells Using Structural Optimization Method
OHASHI Toshiro, SEO Shinji, MATSUMOTO Takeo, SATO Masaaki, Transactions of the Japan Society of Mechanical Engineers. A, 70, 697, 1262, 1268, 25 Sep. 2004
A finite element analysis using structural optimization method was performed to simulate the remodeling of bovine aortic endothelial cells (BAECs) under flow condition. BAECs showed marked elongation and aligned in the flow direction by exposing to a steady shear stress of 2 Pa for 24h. An atomic force microscope (AFM) system was used to obtain cell surface topography, showing that the cell height decreased significantly from 2.8±1.0μm to 1.4±0.5μm with exposure to fluid flow. The fluorescent images of cells stained by rhodamine-phalloidin showed that control cells exhibited dense periphera..., The Japan Society of Mechanical Engineers, Japanese

Mechanical model for adherent cells based on mechanical properties of stress fibers
Deguchi Shinji, Ohashi Toshiro, Sato Masaaki, The proceedings of the JSME annual meeting, 2004, 5, 33, 34, 04 Sep. 2004
In this paper, mechanical architecture of adherent cells such as endothelial cells was discussed based on experimental evaluation of mechanical properties of subcellular structural components. Tensile properties of single stress fibers, bundles of actin filaments, in endothelial cells were obtained with in vitro micromanipulation. Preexisting tension in the stress fibers was then evaluated from the tensile properties and preexisting strain. Physiological tension level of the stress fibers was found to be 1-10 nN order of magnitude, which was "comparable to that of the traction force applied..., The Japan Society of Mechanical Engineers, Japanese

Morphological Responses and VE-cadherin Expression of Cultured Endothelial Cells Exposed to Hydrostatic Pressure
SUGAYA Yoshiaki, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, The proceedings of the JSME annual meeting, 2004, 5, 111, 112, 04 Sep. 2004
Effect of hydrostatic pressure on morphology and expression of VE-cadherin of cultured bovine endothelial cells (ECs) was investigated. After confluent ECs were exposed to hydrostatic pressure of 0, 50, 100 and 150 mmHg for 24 hours, F-actin filaments and VE-cadherin of ECs were stained. Statically cultured ECs formed a cobblestone pattern of contact-inhibited cells with thin, short F-actin filaments. VE-cadherin was uniformly distributed at the periphery of cells. In contrast, ECs exposed to hydrostatic pressure exhibited marked elongation and random orientation, together with development ..., The Japan Society of Mechanical Engineers, Japanese

Mechanical properties and function of the spinal pia mater
H Ozawa, T Matsumoto, T Ohashi, M Sato, S Kokubun, JOURNAL OF NEUROSURGERY-SPINE, 1, 1, 122, 127, Jul. 2004
English

動脈硬化症発生メカニズムにおける内皮細胞と平滑筋細胞の相互作用
坂元 尚哉, 大橋 俊朗, 佐藤 正明, 日本バイオレオロジー学会誌(B&R) = Journal of Japanese Society of Biorheology, 18, 40, 40, 24 May 2004
Japanese

Measurement of Mechanical Properties of Subcellular Components in Adherent Cells(Cellular & Tissue Engineering)
Deguchi Shinji, Ohashi Toshiro, Sato Masaaki, Proceedings of the ... Asian Pacific Conference on Biomechanics : emerging science and technology in biomechanics, 2004, 1, 77, 78, 25 Mar. 2004
The Japan Society of Mechanical Engineers, English

Role of nitric oxide in migration of smooth muscle cells in cocultured model(Cellular & Tissue Engineering)
Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, Proceedings of the ... Asian Pacific Conference on Biomechanics : emerging science and technology in biomechanics, 2004, 1, 83, 84, 25 Mar. 2004
The Japan Society of Mechanical Engineers, English

Significance of Pretension of Single Stress Fibers in Living Smooth Muscle Cells(Micro- and Nano-biomechanics)
Deguchi Shinji, Ohashi Toshiro, Sato Masaaki, Proceedings of the ... Asian Pacific Conference on Biomechanics : emerging science and technology in biomechanics, 2004, 1, 221, 222, 25 Mar. 2004
The Japan Society of Mechanical Engineers, English

508 Local mechanical properties and cytoskeletal structure of vascular endothelial cells
SUZUKI Kenichi, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2004, 39, 186, 187, 13 Mar. 2004
The Japan Society of Mechanical Engineers, Japanese

509 Fluid structural finite element analysis of actin filaments in endothelial cells
IKEDA Takeshi, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2004, 39, 188, 189, 13 Mar. 2004
The Japan Society of Mechanical Engineers, Japanese

Measurement of Mechanical Properties of Cytoskeleton and Nucleus
DEGUCHI Shinji, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2004, 16, 27, 28, 21 Jan. 2004
The Japan Society of Mechanical Engineers, Japanese

Effect of nitric oxide on migration of smooth muscle cells in cocultured model
Sakamoto Naoya, Ohashi Toshiro, Sato Masaaki, バイオエンジニアリング講演会講演論文集, 2004, 16, 31, 32, 21 Jan. 2004
The Japan Society of Mechanical Engineers, Japanese

Measurement of preexisting strain of stress fibers in smooth muscle cells　　　　　　　　　　　　　　　
S Deguchi, T Ohashi, M Sato, Proc. The 43rd Annual Conference of Japanese Society for Medical and Biological Engineering, 2004

Morphological Responses of Aortic Endothelial Cells to Physiological Hydrostatic Pressure　　　　　　　　　　　　　　　
Proceedings of the14th European Society of Biomechanics Conference, 2004

Morphology and Expression of VE-cadherin of Bovine Endothelial Cells Exposed to Hydrostatic Pressure　　　　　　　　　　　　　　　
Proceedings of the BMES Annual Fall Meeting, 2004

Mechanical Properties of a Single Stress Fiber Isolated from Cultured Smooth Muscle Cells　　　　　　　　　　　　　　　
Proceedings of the BMES Annual Fall Meeting, 2004

Morphological Responses of Aortic Endothelial Cells to Physiological Hydrostatic Pressure　　　　　　　　　　　　　　　
Proceedings of the14th European Society of Biomechanics Conference, 2004

Mechanical Properties of a Single Stress Fiber Isolated from Cultured Smooth Muscle Cells　　　　　　　　　　　　　　　
Proceedings of the BMES Annual Fall Meeting, 2004

Morphology and Expression of VE-cadherin of Bovine Endothelial Cells Exposed to Hydrostatic Pressure　　　　　　　　　　　　　　　
Proceedings of the BMES Annual Fall Meeting, 2004

Elongation and random orientation of bovine endothelial cells in response to hydrostatic pressure: Comparison with response to shear stress
Y Sugaya, N Sakamoto, T Ohashi, M Sato, JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 46, 4, 1248, 1255, Dec. 2003
English

Rupture properties of. blood vessel walls measured by pressure-imposed test
T Ohashi, S Sugita, T Matsumoto, K Kumagai, H Akimoto, K Tabayashi, M Sato, JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, 46, 4, 1290, 1296, Dec. 2003
English

Effect of Hydrostatic Pressure on Morphology of Cultured Endothelial Cells
SUGAYA Yoshiaki, SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2003, 14, 3, 4, 17 Sep. 2003
The Japan Society of Mechanical Engineers, Japanese

Mechanical properties of chondrocytes exposed to hydrostatic pressure
ARUGA Noriko, OHASHI Toshiro, SAKAMOTO Naoya, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2003, 14, 17, 18, 17 Sep. 2003
The Japan Society of Mechanical Engineers, Japanese

Measurements of viscoelastic properties of single stress fibers
DEGUCHI Shinji, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... JSME Conference on Frontiers in Bioengineering, 2003, 14, 25, 26, 17 Sep. 2003
The Japan Society of Mechanical Engineers, Japanese

W08-(2) 流れに対する血管内皮細胞の応答機構に関するマイクロバイオメカニクス
佐藤 正明, 山本 嗣雅, 出口 真次, 望月 直樹, 大橋 俊朗, 年次大会講演資料集, 0, 3, 325, 326, 05 Aug. 2003
一般社団法人日本機械学会, Japanese

Measurement of elastic modulus of cell nuclei and observation of their microstructure
DEGUCHI Shinji, MAEDA Kenjiro, OHASHI Toshiro, SATO Masaaki, The proceedings of the JSME annual meeting, 2003, 5, 29, 30, 05 Aug. 2003
The changes in morphology of isolated nuclei nuclei from endothelial cells were investigated before and after exposure to fluid flow. In addition, the Young's modulus of nuclei was determined with pipette aspiration technique. In fluorescence observation, the nuclei in the cells were initially found compressed vertically and the isolated nuclei remained almost rounded shape under static conditions. In contrast, the nuclei before and after isolation showed elongated shape under sheared conditions. These results showed that the compressed nuclei were elongated by fluid flow in the same fashio..., The Japan Society of Mechanical Engineers, Japanese

Dynamic behavior of focal adhesions and associated actin filaments of sheared endothelial cells
OHASHI Toshiro, YAMAMOTO Tsugumasa, MOCHIZUKI Naoki, SATO Masaaki, The proceedings of the JSME annual meeting, 2003, 5, 33, 34, 05 Aug. 2003
Dynamic behavior of actin filaments and focal adhesion targeting (FAT) was observed in endothelial cells during exposure to fluid flow. Cultured bovine aortic endothelial cells were co-transfected with GFP-actin and RFP-FAT using a liposomal method. Fluid shear stress of 2Pa was then applied to confluent endothlial cell monolayer using a parallel-plate flow chamber. During experiments, fluorescence images were observed every 10min up to 50min by a laser scanning microscope. Before exposure to shear stress, a number of small FAT clusters were observed and the distal tip of actin filaments wa..., The Japan Society of Mechanical Engineers, Japanese

Finite element analysis of removable partial denture and mandibular bone based on CT images : Comparison with photoelastic method
SATO Yoshiyuki, SASAKI Tomofumi, ITOH Hidemi, OHASHI Toshiro, SATO Masaaki, The proceedings of the JSME annual meeting, 2003, 7, 7, 8, 05 Aug. 2003
Finite element analysis was performed on mandibular bone with distal extension removable partial denture (RPD) to assess the effects of RPD on stress distributions in mandibular bone. A finite element model was generated using X-ray CT data on the plaster model having the same morphology as the mandibular model, in which the mechanical properties of mandibular bone, natural teeth and RPD were assigned. In the analyses, a vertical loading was applied to the first molar to approximate occlusal loading of teeth. The analytical results showed the high stress concentrations in the distal and api..., The Japan Society of Mechanical Engineers, Japanese

Remodeling of Vascular Endothelial Cells Exposed to Mechanical Stimuli
OHASHI Toshiro, SATO Masaaki, Biophysics, 43, 3, 136, 141, 25 May 2003
Morphology and local mechanical properties of sheared endothelial cells were measured by using atomic force microscope. After applying a steady shear stress of 2 Pa for 6 hours, bovine aortic endothelial cells showed marked elongation and aligned in the flow direction. The peak cell height decreased significantly with exposure to fluid flow. The fluorescent images showed that control cells exhibited dense peripheral bands of F-actin filaments, while sheared cells exhibited F-actin stress fibers which were thick and centrally located parallel to the flow direction. Elastic modulus estimated ..., The Biophysical Society of Japan, Japanese

Temporal Observation of Change in Focal Adhesion Conformation in a Single Endothelial Cell During Exposure to Fluid Flow
YAMAMOTO Tsugumasa, OHASHI Toshiro, MOCHIZUKI Naoki, SATO Masaaki, 講演論文集, 2003, 38, 68, 69, 15 Mar. 2003
The Japan Society of Mechanical Engineers, Japanese

30.細胞骨格引張試験装置の試作と性能評価(平成14年度東北支部大会抄録)
出口 真次, 大橋 俊朗, 佐藤 正明, 生体医工学 : 日本エム・イー学会誌, 41, 1, 69, 69, 10 Mar. 2003
社団法人日本生体医工学会, Japanese

Isolation and stiffness measurement of single stress fibers in vascular smooth muscle cells
DEGUCHI Shinji, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2003, 15, 11, 12, 20 Jan. 2003
The Japan Society of Mechanical Engineers, Japanese

Temporal Observation of Change in Focal Adhesions in Cultured Endothelial Cells Exposed to Shear Stress
YAMAMOTO Tsugumasa, OHASHI Toshiro, MOCHIZUKI Naoki, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2003, 15, 217, 218, 20 Jan. 2003
The Japan Society of Mechanical Engineers, Japanese

Effects of shear stress on morphology and permeability of endothelial cells in cocultured blood vessel model
SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2003, 15, 225, 226, 20 Jan. 2003
The Japan Society of Mechanical Engineers, Japanese

東北大学大学院工学研究科バイオロボティクス専攻バイオメカニクス講座
大橋 俊朗, 佐藤 正明, BME : bio medical engineering, 17, 1, 124, 125, 10 Jan. 2003
Japanese

Remodeling of endothelial nucleus in response to fluid flow　　　　　　　　　　　　　　　
S Deguchi, K Maeda, T Ohashi, M Sato, Proc. The First US National Symposium on Frontiers in Biomechanics, 2003

Oxygen tension modulates Ca2+ response to flow stimulus in endothelial cells exposed to hydrostatic pressure
Toshiro Ohashi, Naoya Sakamoto, Akiyo Iwao, Masaaki Sato, Technology and Health Care, 11, 4, 263, 274, 2003
English

Dynamic Behavior of Focal Adhesion-Associated Proteins of Cultured Endothelial Cells in Shear Flow Conditions　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 2003

Endothelial Cells Exposed to Fluid Shear Stress Regulate Migration of Cocultured Smooth Muscle Cells　　　　　　　　　　　　　　　
Proceedings of the 2003 ASME Summer Bioengineering Conference, 2003

Single Stress Fibers Isolated from Vascular Smooth Muscle Cells Possess Surprisingly High Extensibility　　　　　　　　　　　　　　　
Proceedings of the 2003 ASME Summer Bioengineering Conference, 2003

Temporal Observation of Dynamic Process of Focal Adhesion-Associated Proteins in Sheared Endothelial Cells　　　　　　　　　　　　　　　
Proceedings of the 2003 ASME Summer Bioengineering Conference, 2003

Dynamic Behavior of Focal Adhesion-Associated Proteins of Cultured Endothelial Cells in Shear Flow Conditions　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 2003

Mechanical Properties Differ between Single Stress Fibers and Actin Filaments　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 2003

Mechanical Properties Differ between Single Stress Fibers and Actin Filaments　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 2003

Oxygen Tension Modulates Ca2+ Response to Flow Stimulus in Endothelial Cells Exposed to Hydrostatic Pressure　　　　　　　　　　　　　　　
Technology and Health Care, 11, 4, 263, 274, 2003

Single Stress Fibers Isolated from Vascular Smooth Muscle Cells Possess Surprisingly High Extensibility　　　　　　　　　　　　　　　
Proceedings of the 2003 ASME Summer Bioengineering Conference, 2003

Temporal Observation of Dynamic Process of Focal Adhesion-Associated Proteins in Sheared Endothelial Cells　　　　　　　　　　　　　　　
Proceedings of the 2003 ASME Summer Bioengineering Conference, 2003

Evaluation of Rupture Properties of Human Thoracic Aortic Aneurysms Using a Pressure-Imposed Test　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 2003

Evaluation of Rupture Properties of Human Thoracic Aortic Aneurysms Using a Pressure-Imposed Test　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 2003

Endothelial Cells Exposed to Fluid Shear Stress Regulate Migration of Cocultured Smooth Muscle Cells　　　　　　　　　　　　　　　
Proceedings of the 2003 ASME Summer Bioengineering Conference, 2003

Local elastic modulus of atherosclerotic lesions of rabbit thoracic aortas measured by pipette aspiration method
Takeo Matsumoto, Hironobu Abe, Toshiro Ohashi, Yoko Kato, Masaaki Sato, Physiological Measurement, 23, 4, 635, 648, Nov. 2002
English

Measurement of Breaking Properties of Human Aneurysm Specimens
OHASHI Toshiro, SUGITA Syukei, MATSUMOTO Takeo, KUMAGAI Kiichiro, AKIMOTO Hiroji, TABAYASHI Koichi, SATO Masaaki, The proceedings of the JSME annual meeting, 2002, 1, 121, 122, 20 Sep. 2002
A newly designed experimental setup was fabricated to measure rupture properties of aortic aneurysms. Square specimen obtained from human thoracic aortic aneurysms was inflated by air pressure at a rate of 10 mmHg/s until rupture occurs. Deformation process was observed through two CCD cameras and a high-speed camera. Mean breaking stress and strain were estimated from the specimen geometry considering incompressibility, resulting in 0.97±0.39Mpa (mean±SD) and 0.64±0.10,respectively. Moreover, significant difference was found between mean breaking stress and area fraction of collagen fibers..., The Japan Society of Mechanical Engineers, Japanese

Effect of Culture in Gels on the Differentiated State of Chondrocytes
OHASHI Toshiro, IKEDA Takeshi, MATSUMOTO Takeo, SATO Masaaki, The proceedings of the JSME annual meeting, 2002, 6, 75, 76, 20 Sep. 2002
To determine the effect of extracellular matrix on chondrocytes, mechanical properties and production of type II collagen of chondrocytes were measured. Isolated bovine articular chondrocytes were cultured on a culture dish for 3 weeks and then embedded in a type I collagen gels. After 3-4 weeks, the chondrocytes were excised from the constructs and a pipette aspiration test was performed. The Young's modulus significantly increased when the chondrocytes were embedded in the collagen gels, which corresponded to the development in cytoskeletal structure. In addition, type II collagen was obs..., The Japan Society of Mechanical Engineers, Japanese

Measurement of Morphology and Local Mechanical Properties of Cultured Endothelial Cells Exposed to Shear Stress
OHASHI Toshiro, SEO Shinji, ISHII Yasuaki, ISHIKAWA Yasushi, MATSUMOTO Takeo, SATO Masaaki, 生体・生理工学シンポジウム論文集, 17, 15, 18, 09 Sep. 2002
Japanese

Three-dimensional finite element analyses of the abutment teeth and the remaining structures of mandibular distal extension dentures using CT images
SATO Yoshiyuki, OHASHI Toshiro, SASAKI Tomofumi, ITOH Hidemi, TAKAHASHI Shoki, MATSUMOTO Takeo, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2002, 13, 3, 4, 04 Sep. 2002
The Japan Society of Mechanical Engineers, Japanese

Change in Mechanical Properties of Individual Chondrocytes Embedded in Gels
IKEDA Takeshi, OHASHI Toshiro, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2002, 13, 13, 14, 04 Sep. 2002
The Japan Society of Mechanical Engineers, Japanese

Effect of shear stress on migration of smooth muscle cells cocultured with endothelial cells
SAKAMOTO Naoya, OHASHI Toshiro, MATSUMOTO Takeo, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2002, 13, 93, 94, 04 Sep. 2002
The Japan Society of Mechanical Engineers, Japanese

Targeted disruption of dermatopontin causes abnormal collagen fibrillogenesis
U Takeda, A Utani, JH Wu, E Adachi, H Koseki, M Taniguchi, T Matsumoto, T Ohashi, M Sato, H Shinkai, JOURNAL OF INVESTIGATIVE DERMATOLOGY, 119, 3, 678, 683, Sep. 2002
English

Stress Analysis of Abutment Teeth in Distal Extension Mandibular : Role of Rest of Circumferential Clasps
SATO Yoshiyuki, OHASHI Toshiro, ITOH Hidemi, SASAKI Tomofumi, SATO Masaaki, TAKAHASHI Shoki, Proceedings of JSEM, 2, 78, 80, 05 Aug. 2002
日本実験力学会, Japanese

流れ刺激を受ける内皮細胞内骨格構造の実時間挙動観察
Ohashi Toshiro, Tsuyuki Kei, Sato Masaaki, 日本バイオレオロジー学会誌, 25, 10, 24, 28, 13 May 2002
Actin filament dynamics in endothelial cells was observed during exposure to fluid shear stress. A plasmid encoding enhanced green fluorescent protein (GFP) fused to the amino terminus of actin was transfected into cultured bovine aortic endothelial cells (BAECs) using a liposomal method. This functional GFP-actin construct enabled observation of actin filaments in BAECs. BAECs were exposed to fluid shear stress of 2 Pa using a parallel plate flow chamber and dynamic behavior of actin filaments in BAECs expressing stable GFP-actin was observed under a time lapse fluorescence microscopy. Cytoskeletal reorganization during exposure to shear stress preceded changes in cell shape. In a typical example, dense peripheral bands located upstream side in a cell moved toward the nucleus and fine network structure of actin filaments was partly destroyed within 60 min. After 180 min, actin filaments started to form thick bundles in the whole region of the cell, followed by cell elongation to the flow direction. Changes in cell shape and cytoskeletal structure seemed to be finished around 300 min. The GFP-actin expressed in endothelial cells should reveal detailed moving process of actin filaments in endothelial cells under mechanical stimuli., JAPANESE SOCIETY OF BIORHEOLOGY, Japanese

Measurement of Rupture Property of Human Aneurysms Using Pressure-Imposed Experiment
SUGITA Syukei, OHASHI Toshiro, MATSUMOTO Takeo, KUMAGAI Kiichiro, AKIMOTO Hiroji, TABAYASHI Koichi, SATO Masaaki, 講演論文集, 2002, 37, 66, 67, 16 Mar. 2002
The Japan Society of Mechanical Engineers, Japanese

Real time observation of cytoskeletal change in a single endothelial cell using EGFP-gene transfection method
TSUYUKI Kei, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2002, 37, 182, 183, 16 Mar. 2002
The Japan Society of Mechanical Engineers, Japanese

Measurement of Breaking Property of Human Aneurysms Using Pressure-imposed Experiment
SUGITA Syukei, OHASHI Toshiro, MATSUMOTO Takeo, KUMAGAI Kiichiro, AKIMOTO Hiroji, TABAYASHI Koichi, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2002, 14, 123, 124, 01 Mar. 2002
The Japan Society of Mechanical Engineers, Japanese

Real time observation of cytoskeletal change in a single endothelial cell exposed to fluid shear stress
TSUYUKI Kei, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2002, 14, 129, 130, 01 Mar. 2002
The Japan Society of Mechanical Engineers, Japanese

Effects of oxygen tension and hydrostatic pressure on Ca^<2+> response of endothelial cells under shear shress
SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2002, 14, 253, 254, 01 Mar. 2002
The Japan Society of Mechanical Engineers, Japanese

Experimental and numerical analyses of local mechanical properties measured by atomic force microscopy for sheared endothelial cells
T Ohashi, Y Ishii, Y Ishikawa, T Matsumoto, M Sato, BIO-MEDICAL MATERIALS AND ENGINEERING, 12, 3, 319, 327, 2002
English

Changes in Local Mechanical Properties and Actin Filament Distribution in Endothelial Cells Exposed to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the 11th International Congress of Biorheology, 2002

Rupture Properties of Thoracic Aortic Aneurysms Using Pressure-Imposed Experiment　　　　　　　　　　　　　　　
Proceedings of the IV World Congress of Biomechanics, 2002

Effect of Magnetic Field on Nitric Oxide Synthesis of Cultured Endothelial Cells　　　　　　　　　　　　　　　
International Journal Applied Electromagnetics and Mechanics, 14, 317, 322, 2002

Experimental and numerical analyses of local mechanical properties measured by atomic force microscopy for sheared endothelial cells
Toshiro Ohashi, Y. Ishii, Y. Ishikawa, T. Matsumoto, M. Sato, Bio-Medical Materials and Engineering, 12, 3, 319, 327, 2002
English

Measurement of Rupture Properties of Thoracic Aortic Aneurysms Using Pressure-Imposed Test　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Biaxial Tensile Properties of Aortic Aneurysm Tissues under Equibiaxial Stress　　　　　　　　　　　　　　　
Proceedings of the IV World Congress of Biomechanics, 2002

Effect of Magnetic Field on Nitric Oxide Synthesis of Cultured Endothelial Cells　　　　　　　　　　　　　　　
International Journal Applied Electromagnetics and Mechanics, 14, 317, 322, 2002

Structural Optimization Analysis of Endothelial Cell Remodeling to Fluid Flow　　　　　　　　　　　　　　　
Proceedings of the 2nd Joint EMBS & BMES conference, 2002

Biaxial Tensile Properties of Aortic Aneurysm Tissues under Equibiaxial Stress　　　　　　　　　　　　　　　
Proceedings of the IV World Congress of Biomechanics, 2002

Dynamic Behavior of Focal Adhesion - Associated Proteins of Endothelial cells in The Early Stage of Shear Stress Exposure　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Dynamic Behavior of Focal Adhesion - Associated Proteins of Endothelial cells in The Early Stage of Shear Stress Exposure　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Observation of Actin Filament Movement and Remodeling Process of Endothelial Cells During Exposure to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Measurement of Rupture Properties of Thoracic Aortic Aneurysms Using Pressure-Imposed Test　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Dynamic Behavior of Actin Filaments in Cultured Endothelial Cells During Exposure to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the IV World Congress of Biomechanics, 2002

Observation of Actin Filament Movement and Remodeling Process of Endothelial Cells During Exposure to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Structural Optimization Analysis of Endothelial Cell Remodeling to Fluid Flow　　　　　　　　　　　　　　　
Proceedings of the 2nd Joint EMBS & BMES conference, 2002

Rupture Properties of Thoracic Aortic Aneurysms Using Pressure-Imposed Experiment　　　　　　　　　　　　　　　
Proceedings of the IV World Congress of Biomechanics, 2002

Fluid Shear Stress Affects Migration of Vascular Smooth Muscle Cells Cocultured with Endothelial Cells　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Fluid Shear Stress Affects Migration of Vascular Smooth Muscle Cells Cocultured with Endothelial Cells　　　　　　　　　　　　　　　
Proceedings of the International Congress on Biological and Medical Engineering, 2002

Deformation properties of articular chondrocytes: A critique of three separate techniques
DL Bader, T Ohashi, MM Knight, DA Lee, M Sato, BIORHEOLOGY, 39, 1-2, 69, 78, 2002
English

Changes in Local Mechanical Properties and Actin Filament Distribution in Endothelial Cells Exposed to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the 11th International Congress of Biorheology, 2002

Dynamic Behavior of Actin Filaments in Cultured Endothelial Cells During Exposure to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the IV World Congress of Biomechanics, 2002

Application of scanning acoustic microscopy for assessing stress distribution in atherosclerotic plaque
Y Saijo, T Ohashi, H Sasaki, M Sato, CS Jorgensen, SI Nitta, ANNALS OF BIOMEDICAL ENGINEERING, 29, 12, 1048, 1053, Dec. 2001
English

1C11 Real time observation of change in actin structure in a single endothelial cell under fluid shear stress
TSUYUKI Kei, OHASHI Toshiro, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2001, 12, 85, 86, 26 Oct. 2001
The Japan Society of Mechanical Engineers, Japanese

2A11 Effect of mechanical conditions on elastic modulus of chondrocytes
MASUDA Masanori, OHASHI Toshiro, MATSUMOTO Takeo, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2001, 12, 131, 132, 26 Oct. 2001
The Japan Society of Mechanical Engineers, Japanese

2A12 Application of micropipette aspiration technique to measurement of adhesion force of cultured endothelial cells
YAMAMOTO Tsugumasa, OHASHI Toshiro, SATO Masaaki, The ... JSME Bioengineering Conference and Seminar, 2001, 12, 133, 134, 26 Oct. 2001
The Japan Society of Mechanical Engineers, Japanese

2C31 Measurement of biaxial tensile properties of human aneurysm specimens considering their positions in the aneurysm
Fukui Tomohiro, Matsumoto Takeo, Kumagai Kiichiro, Akimoto Hiroji, Tabayashi Koichi, Ohashi Toshiro, Sato Masaaki, The ... JSME Bioengineering Conference and Seminar, 2001, 12, 195, 196, 26 Oct. 2001
The Japan Society of Mechanical Engineers, Japanese

Comparison of spinal cord ray matter and white matter softness: measurement by pipette aspiration method
H Ozawa, T Matsumoto, T Ohashi, M Sato, S Kokubun, JOURNAL OF NEUROSURGERY, 95, 2, 221, 224, Oct. 2001
English

108 The Estimation of Machanical Properties of Two-Layered Structure Simulating Dermis and Epidermis by Pipette Aspiration Method
NAGANO Yujiro, MATSUMOTO Takeo, KAWAWA Takuo, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2001, 15, 16, 21 Sep. 2001
The Japan Society of Mechanical Engineers, Japanese

F-0822 Structural optimization analysis of sheared endothelial cells using ALE method
OHASHI Toshiro, SEO Shinji, MATSUMOTO Takeo, SATO Masaaki, The proceedings of the JSME annual meeting, 0, 1, 43, 44, 22 Aug. 2001
A finite element analysis using structural optimization method was performed to simulate the remodeling of bovine aortic endothelial cells (BAECs), in which cell surface geometries were measured by an atomic force microscope (AFM) system. After applying a steady shear stress of 2 Pa for 24 hours, BAECs showed marked elongation and aligned in the flow direction. In the AFM measurements, the peak cell height decreased significantly from 2.8 ± 1.0 μm to 1.4 ± 0.5 μm with exposure to fluid flow. The fluorescent images showed that control cells exhibited dense peripheral bands of F-actin filamen..., The Japan Society of Mechanical Engineers, Japanese

F-0937 Effect of low oxgen gas condition on Ca^<2+> response of cultured endothelial cells under shear stress
SAKAMOTO Naoya, OHASHI Toshiro, IWAO Akiyo, SATO Masaaki, The proceedings of the JSME annual meeting, 0, 1, 99, 100, 22 Aug. 2001
Intracellular calcium response to a flow stimulus and morphological changes in sheared endothelial cells were investigated under arterial and venous gas conditions. Prior to the flow stimulus experiments, the endothelial cells were exposed to shear stress of 2 Pa for 6 hours using a parallel-plate flow chamber. Maximum fluorescent intensity of intracellular calcium for venous gas condition was significantly lower than that for arterial gas condition, which provides evidence that low oxygen tensions downregulate cellular physiological functions. However, preloading of shear stress prevented ..., The Japan Society of Mechanical Engineers, Japanese

114 Basic Study on the Estimation of Mechanical Properties of Layered Structures from Their Surface by Pipette Aspiration Method
MATSUMOTO Takeo, NAGANO Yujiro, KAWAWA Takuo, OHASHI Toshiro, SATO Masaaki, Proceedings of the ... annual meeting of JSME/MMD, 2001, 35, 36, 19 Jul. 2001
The Japan Society of Mechanical Engineers, Japanese

せん断応力負荷と血管内皮細胞内アクチンフィラメントの再配列
佐藤 正明, 露木 啓, 大橋 俊朗, 日本バイオレオロジー学会年会抄録集, 24, 37, 37, 28 May 2001
Japanese

Structural Optimization Method of Sheared Endothelial Cells Using Coupled Fluid-Structural Analysis　　　　　　　　　　　　　　　
大橋俊朗, 清尾慎司, 松本健郎, 佐藤正明, 日本数値流体力学会雑誌, 9, 4, 99, 105, Apr. 2001

122 Development of stiffness measurement system of biological soft tissues by pipette aspiration with micro optical sensor
OHASHI Toshiro, MATSUMOTO Takeo, SATO Masaaki, Conference on Information, Intelligence and Precision Equipment : IIP, 2001, 72, 73, 23 Mar. 2001
The Japan Society of Mechanical Engineers, Japanese

203 Computational analysis on structure of cultured endothelial cell exposed to shear stress using optimization method
SEO Shinji, OHASHI Toshiro, MATSUMOTO Takeo, SATO Masaaki, 講演論文集, 2001, 36, 52, 53, 10 Mar. 2001
The Japan Society of Mechanical Engineers, Japanese

Quantitative Study of the Relation between the Histology and the Local Elastic Modulus of Atherosclerotic Legions in Rabbit Thoracic Aortas
KATO Y, MATSUMOTO T, OHASHI T, SATO M, 脈管学, 41, 1, 23, 29, 25 Jan. 2001
Japanese

Change in Mechanical Properties of Individual Chondrocytes with Time in Culture
OHASHI Toshiro, FUJITA Manabu, MASUDA Masanori, MATSUMOTO Takeo, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2001, 13, 10, 11, 15 Jan. 2001
The Japan Society of Mechanical Engineers, Japanese

Alignment of cultured vascular smooth muscle cells on microgrooved substrata
SAKAMOTO Naoya, OHASHI Toshiro, MATSUMOTO Takeo, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2001, 13, 176, 177, 15 Jan. 2001
The Japan Society of Mechanical Engineers, Japanese

Analysis of Morphology and Stress Distribution in Sheared Endothelial Cells Using Structural Optimization Method
SEO Shinji, OHASHI Toshiro, MATSUMOTO Takeo, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2001, 13, 200, 201, 15 Jan. 2001
The Japan Society of Mechanical Engineers, Japanese

Basic Study on the Estimation of Mechanical Properties of Epidermis and Dermis
MATSUMOTO Takeo, KAWAWA Takuo, NAGANO Yujiro, OHASHI Toshiro, SATO Masaaki, バイオエンジニアリング講演会講演論文集, 2001, 13, 228, 229, 15 Jan. 2001
The Japan Society of Mechanical Engineers, Japanese

Effect of Magnetic Field on Nitric Oxide Synthesis of Cultured Endothelial Cells　　　　　　　　　　　　　　　
International Journal Applied Electromagnetics and Mechanics, 14, 317, 322, 2001

Analysis of Local Mechanical Properties of Sheared Endothelial Cells Measured by Atomic Force Microscopy　　　　　　　　　　　　　　　
Proceedings of the ASME 2001 Summer Bioengineering Conference, 2001

Analysis of Local Mechanical Properties of Sheared Endothelial Cells Measured by Atomic Force Microscopy　　　　　　　　　　　　　　　
Proceedings of the ASME 2001 Summer Bioengineering Conference, 2001

流体ー構造連成解析による流れ負荷培養内皮細胞の構造最適化シミュレーション　　　　　　　　　　　　　　　
日本数値流体力学会誌特集「CFD関連分野における連成シミュレーション」, 9, 4, 99, 105, 2001

Effect of magnetic field on nitric oxide synthesis of cultured endothelial cells
N Sakamoto, T Ohashi, M Sato, INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, 14, 1-4, 317, 322, 2001
English

Stress Distribution and Heterogeneous Structure in Cultured Endothelial Cells Exposed to Fluid Shear Stress
OHASHI Toshiro, SEO Shinji, SATO Masaaki, The Computational Mechanics Conference, 2000, 13, 219, 220, 27 Nov. 2000
The Japan Society of Mechanical Engineers, Japanese

有限要素法による流れ負荷培養内皮細胞の力学的解析
大橋 俊朗, 松本 健郎, 佐藤 正明, BME : bio medical engineering, 14, 10, 21, 24, 10 Oct. 2000
Japanese

Stress Distribution Analysis Based on Heterogeneous Structure in Cultured Endothelial Cells Exposed to Fluid Shear Stress
SEO Shinji, OHASHI Toshiro, ISHII Yasuaki, SATO Masaaki, The proceedings of the JSME annual meeting, 2000, 2, 253, 254, 31 Jul. 2000
The Japan Society of Mechanical Engineers, Japanese

Changes in Nitric Oxide Production of Cultured Endothelial Cells by Oscillating Magnetic Field
SAKAMOTO Naoya, OHASHI Toshiro, SATO Masaaki, The proceedings of the JSME annual meeting, 2000, 2, 269, 270, 31 Jul. 2000
The Japan Society of Mechanical Engineers, Japanese

Measurement of Local Mechanical Properties of Cultured Endothelial Cells Exposed to Shear Stress with Atomic Force Microscopy
OHASHI Toshiro, ISHII Yasuaki, SATO Masaaki, The proceedings of the JSME annual meeting, 2000, 2, 273, 274, 31 Jul. 2000
The Japan Society of Mechanical Engineers, Japanese

Mechanical Analysis of Sheared Endothelial Cells by Finite Element Method
Ohashi Toshiro, Seo Shinji, Sato Masaaki, Proceedings, ... meeting of Japan Society of Fluid Mechanics, 2000, 259, 260, 25 Jul. 2000
In this paper, intracellular stress distributions in cultured endothelial cells exposed to fluid shear stress were studied using coupled field finite element analysis, in which cell surface geometries are measured by an atomic force microscope (AFM). After application of 6 h exposure to shear stress of 2 Pa, the endothelial cells showed marked elongation and orientation in the flow direction. A three-dimensional finite element model was generated on the basis of the cell surface geometry measured by the AFM. A fluid flow-structural analysis indicated that the endothelial cells may change th..., Japan Society of Fluid Mechanics, Japanese

磁場刺激による培養内皮細胞のNO産生の変化
坂元 尚哉, 大橋 俊朗, 佐藤 正明, 運動療法と物理療法 = The Journal of physical medicine, 11, 3, 244, 244, 08 Jun. 2000
Japanese

(1)矩形断面ピペットを使った生体軟組織弾性率の測定に関する解析と実験
大橋 俊朗, 安倍 裕宣, 松本 健郎, 青木 隆平, 佐藤 正明, 日本機械学會誌, 103, 978, 281, 281, 05 May 2000
一般社団法人日本機械学会, Japanese

Measurement of the mechanical properties of soft biological tissues by the pipette aspiration method
MATSUMOTO Takeo, OHASHI Toshiro, SATO Masaaki, OZAWA Hiroshi, KOKUBUN Shoichi, 運動療法と物理療法 = The Journal of physical medicine, 11, 1, 2, 10, 30 Apr. 2000
Japanese

Biomechanical role of the pia mater in spinal cord deformation
OZAWA Hiroshi, KOKUBUN Shoichi, MATSUMOTO Takeo, OHASHI Toshiro, SATO Masaaki, 運動療法と物理療法 = The Journal of physical medicine, 11, 1, 11, 16, 30 Apr. 2000
Japanese

521 Effect of O_2/CO_2 condition on Ca^<2+> response of cultured endothelial cells exposed to shear stress
IWAO Akiyo, OHASHI Toshiro, SATO Masaaki, 講演論文集, 2000, 35, 198, 199, 11 Mar. 2000
The Japan Society of Mechanical Engineers, Japanese

Changes in Local Mechanical Stiffness of Cultured Endothelial Cells by Exposure to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the 12th Conference of the European Society of Biomechanics, 2000

Oscillating Magnetic Field Affects NO Synthesis of Cultured Endothelial Cell　　　　　　　　　　　　　　　
Proceedings of the 10th International Conference on Biomedical Engineering, 2000

Oscillating Magnetic Field Affects NO Synthesis of Cultured Endothelial Cell　　　　　　　　　　　　　　　
Proceedings of the 10th International Conference on Biomedical Engineering, 2000

Changes in Local Mechanical Stiffness of Cultured Endothelial Cells by Exposure to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the 12th Conference of the European Society of Biomechanics, 2000

The Mechanical Response of Individual Chondrocytes　　　　　　　　　　　　　　　
Proceedings of the 12th Conference of the European Society of Biomechanics, 2000

The Mechanical Response of Individual Chondrocytes　　　　　　　　　　　　　　　
Proceedings of the 12th Conference of the European Society of Biomechanics, 2000

Surface topography measurement and intracellular stress analysis of cultured endothelial cells exposed to fluid shear stress
T. Ohashi, S. Sugawara, T. Matsumoto, M. Sato, JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing, 43, 4, 780, 786, 2000
Japan Society of Mechanical Engineers, English

A histological image analysis method using color classification based on Mahalanobis' generalized distance and the application to arterial tissues
Kato Yoko, Matsumoto Takeo, Ohashi Toshiro, Sato Masaaki, IEICE technical report., 99, 191, 1, 5, 16 Jul. 1999
It has been suggested that local elastic moduli of soft biological tissues have a close correlation with their histology. We have developed an image analysis method in which structural components in histological images are classified based on their color tones to obtain their area fractions, and studied the relation between local elastic moduli of tissues and their histology quantitatively. Histological analysis was carried out of bovine thoracic aortas and atherosclerotic legions in rabbit thoracic aortas, whose local elastic moduli had been measured with a pipette aspiration technique. Th..., The Institute of Electronics, Information and Communication Engineers, Japanese

ANALYTICAL STUDIES ON THE MEASUREMENT OF SOFT BIOLOGICAL TISSUE ELASTICITY USING PIPETTES WITH CIRCULAR AND RECTANGULAR CROSS SECTIONS
OHASHI Toshiro, MATSUMOTO Takeo, AOKI Takahira, SATO Masaaki, 計算工学講演会論文集, 4, 2, 1059, 1060, 26 May 1999
Japanese

3-D Stress Analysis in Cultured Endothelial Cells Exposed to Fluid Shear Stress　　　　　　　　　　　　　　　
Proceedings of the 1999 ASME International Mechanical Engineering Congress and Exposition, 1999

3-D Stress Distribution in Cultured Endothelial Cells Exposed to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the First Joint Meeting of BMES & EMBS, 1999

3-D Stress Distribution in Cultured Endothelial Cells Exposed to Shear Stress　　　　　　　　　　　　　　　
Proceedings of the First Joint Meeting of BMES & EMBS, 1999

Local Elastic Modulus of Atherosclerotic Lesions of Rabbit Thoracic Aortas and Its Relation to Histology　　　　　　　　　　　　　　　
Proceedings of the First Joint Meeting of BMES & EMBS, 1999

Theoretical Analysis of Optically Addressed Spatial Light Modulator with Electromagnetic Driven Micromirror for Optical Information Processing
Toshiro Ohashi, Mitsunobu Yoshida, Kazuhiro Hane, IEEJ Transactions on Sensors and Micromachines, 119, 42591, 424, 429, 1999
English

3-D Stress Analysis in Cultured Endothelial Cells Exposed to Fluid Shear Stress　　　　　　　　　　　　　　　
Proceedings of the 1999 ASME International Mechanical Engineering Congress and Exposition, 1999

Local Elastic Modulus of Atherosclerotic Lesions of Rabbit Thoracic Aortas and Its Relation to Histology　　　　　　　　　　　　　　　
Proceedings of the First Joint Meeting of BMES & EMBS, 1999

Optical Encoder Having Pitch-Modulated Photodiode Array
Toshiro Ohashi, Takayuki Hirano, Minoru Sasaki, Kazuhiro Hane, Atsushi Ieki, Keiji Matsui, Masayuki Nashiki, IEEJ Transactions on Sensors and Micromachines, 119, 2, 86, 93, 1999
English

Intramural distribution of elastic moduli in thoracic aortas and its relationship to histology : Comparison between porcine and bovine thoracic aortas
Toshiro Ohashi, Yoko Kato, Takeo Matsumoto, Masaaki Sato, JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing, 42, 3, 568, 573, 1999
Japan Society of Mechanical Engineers, English

Analysis and Fabrication of Torsional Probes for Atomic Force Microscope Data Reading
TANAKA Kotaro, OHASHI Toshiro, GOTO Kazuya, HANE Kazuhiro, シンポジウム電磁力関連のダイナミックス講演論文集, 10, 121, 122, 23 Oct. 1998
Japanese

Coupled Magneto-Structural Analysis of Electromagnetic Driven Micromirror by Using Finite Element Method
YOSHIDA Mitsunobu, OHASHI Toshiro, HANE Kazuhiro, シンポジウム電磁力関連のダイナミックス講演論文集, 10, 123, 124, 23 Oct. 1998
Japanese

Mechanical Properties and Response of the Spinal Cord to Compressive Stress
OZAWA H, 日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association, 71, 8, S1400, 25 Aug. 1997
Japanese

The pipette aspiration applied to the local stiffness measurement of soft tissues
T Aoki, T Ohashi, T Matsumoto, M Sato, ANNALS OF BIOMEDICAL ENGINEERING, 25, 3, 581, 587, May 1997
English

Analytical and Experimental Studies on the Measurement of Soft Biological Tissue Elasticity using a Pipette with Rectangular Cross Section
OHASHI Toshiro, ABE Hironobu, MATSUMOTO Takeo, AOKI Takahira, SATO Masaaki, Transactions of the Japan Society of Mechanical Engineers. C, 63, 607, 867, 874, 25 Mar. 1997
A pipette aspiration technique has been developed to clarify the local anisotropic stiffness of soft biological tissues. This technique provides a simple and practical method of measuring an initial elastic modulus by comparing the slope of the pressure-deformation curve obtained from a finite element analysis with that obtained by experiment using a pipette to aspirate the tissue surface. In previous studies, linear numerical simulations were performed for circular cross-sectional pipettes using an axisymmetric model that is assumed to be isotropic and homogeneous. In this paper, the use o..., The Japan Society of Mechanical Engineers, Japanese

Intramural Distribution of Local Elastic Moduli in Bovine Thoracic Aorta Measured by Pipette Aspiration Method　　　　　　　　　　　　　　　
Cellular Engineering, 2, 1, 12, 18, 1997

Intramural distribution of local elastic moduli in bovine thoracic aorta measured by pipette aspiration method　　　　　　　　　　　　　　　
Cellular Engineering, 2, 1, 12, 18, 1997

Intramural distribution of local elastic moduli in bovine thoracic aorta measured by pipette aspiration method　　　　　　　　　　　　　　　
Cellular Engineering, 2, 1, 12, 18, 1997

The pipette aspiration applied to the local stiffness measurement of soft tissues
Takahira Aoki, Toshiro Ohashi, Takeo Matsumoto, Masaaki Sato, Annals of Biomedical Engineering, 25, 3, 581, 587, 1997
American Institute of Physics Inc., English

Intramural Distribution of Local Elastic Moduli in Bovine Thoracic Aorta Measured by Pipette Aspiration Method　　　　　　　　　　　　　　　
Cellular Engineering, 2, 1, 12, 18, 1997

Local Mechanical Properties in Aortic Walls Measured by Pipette Technique　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 1997

Local Mechanical Properties in Aortic Walls Measured by Pipette Technique　　　　　　　　　　　　　　　
Proceedings of the World Congress on Medical Physics and Biomedical Engineering, 1997

Measurement of Mechanical Properties of Spinal Cord by Pipette Method
OZAWA H, 日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association, 70, 8, S1563, 25 Aug. 1996
Japanese

Local Elastic Moduli of Bovine and Porcine Aortic Walls Measured with Pipette Aspiration Technique　　　　　　　　　　　　　　　
1995 Advances in Bioengineering, 1995

Local Elastic Moduli of Bovine and Porcine Aortic Walls Measured with Pipette Aspiration Technique　　　　　　　　　　　　　　　
1995 Advances in Bioengineering, 1995

Application of the Pipette Aspiration Technique to the Measurement of Local Elastic Moduli of Cholesterol-fed Rabbit Aortas　　　　　　　　　　　　　　　
Theoretical and Applied Mechanics, 43, 233, 238, 1994

Application of the Pipette Aspiration Technique to the Measurement of Local Elastic Moduli of Cholesterol-fed Rabbit Aortas　　　　　　　　　　　　　　　
Theoretical and Applied Mechanics, 43, 233, 238, 1994

Local Mechanical Properties of Cholesterol-fed Rabbit Aortae Measured by the Pipette Aspiration Technique　　　　　　　　　　　　　　　
Proceedings of the 2nd World Congress of Biomechanics, 1994

Local Mechanical Properties of Cholesterol-fed Rabbit Aortae Measured by the Pipette Aspiration Technique　　　　　　　　　　　　　　　
Proceedings of the 2nd World Congress of Biomechanics, 1994

Finite Element Analysis of Local Deformation of Soft Tissues Aspirated by Pipette　　　　　　　　　　　　　　　
Proceedings of the 2nd World Congress of Biomechanics, 1994

Finite Element Analysis of Local Deformation of Soft Tissues Aspirated by Pipette　　　　　　　　　　　　　　　
Proceedings of the 2nd World Congress of Biomechanics, 1994

ナノメデイシンの基礎と最先端　　　　　　　　　　　　　　　
株式会社オーム社, 2008

MEME/NEMS工学大全　　　　　　　　　　　　　　　
株式会社テクノシステム, 2008

Future Medical Engineering Based on Bionanotechnology　　　　　　　　　　　　　　　
Imperial College Press, 2007

Future Medical Engineering Based on Bionanotechnology　　　　　　　　　　　　　　　
Imperial College Press, 2007

Human Biomechanics and Injury Prevention　　　　　　　　　　　　　　　
Springer-Verlag, 2000

Human Biomechanics and Injury Prevention　　　　　　　　　　　　　　　
Springer-Verlag, 2000

Data Book on Mechanical Properties of Living Cells, Tissues, and Organs　　　　　　　　　　　　　　　
Springer-Verlag, 1996

Data Book on Mechanical Properties of Living Cells, Tissues, and Organs　　　　　　　　　　　　　　　
Springer-Verlag, 1996

マトリックスデバイスによる細胞の力学伝達経路の解明　　　　　　　　　　　　　　　
2006 - 2007

最適な腰椎牽引療法を目指した有限要素法解析　　　　　　　　　　　　　　　
2007

生体内微小循環動態評価に関する研究　　　　　　　　　　　　　　　
2006 - 2006

Bio-MEMSによる細胞操作に関する研究　　　　　　　　　　　　　　　
2006

コラーゲン・トリペプチド（CTP）の軟骨細胞および血管内皮細胞に対する機能性評価　　　　　　　　　　　　　　　
2004

最適なステント設計のための有限要素法解析　　　　　　　　　　　　　　　
2003 - 2003

ラミン欠損核の力学特性に関する研究　　　　　　　　　　　　　　　
2002 - 2002

Resiliometerを用いた皮膚力学特性の計測に関する有限要素法解析　　　　　　　　　　　　　　　
2002 - 2002

ヒト繊維芽細胞の力学特性に関する研究　　　　　　　　　　　　　　　
2000 - 2000

軟骨細胞の力学応答機構に関する研究　　　　　　　　　　　　　　　
1998

細胞一次繊毛の形成制御とトンネルナノチューブへの細胞工学応用
科学研究費助成事業
01 Apr. 2023 - 31 Mar. 2026
大橋 俊朗, 豊原 涼太
日本学術振興会, 基盤研究(B), 北海道大学, 23H03707

Study on mechanism of endothelial mechanotransduction by using micro-mechanical manipulation technique
Grants-in-Aid for Scientific Research Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
07 Oct. 2019 - 31 Mar. 2023
大橋 俊朗, 東藤 正浩, 山田 悟史
細胞は周囲の力学環境に適応して自らの形態および機能を変化させることが知られている．これは細胞が力学刺激を感知・伝達し生化学的信号に変換しているためでありこの機構はメカノトランスダクションと呼ばれている．例えば，血管内皮細胞は血流に応答して血流方向に伸長・配向することから盛んに研究が行われてきたがメカノトランスダクション機構の全容は明らかではない．本申請課題の目的は，磁気ナノビーズ技術を高度に駆使して流れ刺激に対する内皮細胞の力学伝達経路の推定するものである．近年では，内皮細胞表面に突出する直径0.2ミクロン，長さ数ミクロン～十数ミクロン程度の線状のPrimary ciliumが力学刺激の感知に深く寄与していることが指摘されている．
以上の背景の下，磁気ナノビーズ技術およびマイクロフルイディクス技術により内皮細胞に力学刺激を負荷する部位を空間的に制御し，内皮細胞の流れ負荷応答のメカニズムを新しい視点で探求するものである．研究代表者の大橋がこれまでに従事してきた流れ負荷内皮細胞実験技術，マイクロフルイディクス技術および海外共同研究者のProf. Ibarraより新たに導入する磁気ナノビーズ技術を高度に融合させ，海外共同研究者のProf. Longとともに流れ負荷刺激を模擬して磁気ナノビーズにより力学刺激部位を空間的に制御することにより，流れ負荷によるメカノトランスダクション機構を検討するものである．今年度は磁気ナノビーズを人工細胞内に導入し生細胞と共培養する実験系の確立に着手してきた．外部磁場を負荷することで人工細胞を駆動させることができるため細胞間力を任意に調整することが可能であり，細胞間の力学情報伝達経路を探求するものである．また，Primary ciliumの変形から力学特性を計測できる可能性が示唆されたため，Primary ciliumの力学特性計測という新しい研究展開も図った．
Japan Society for the Promotion of Science, Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)), Hokkaido University, 19KK0276

Mechanical characteristics of endothelial primary cilium and understanding of its mechanosensing mechanism
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2018 - 31 Mar. 2021
Ohashi Toshiro
The purpose of this study is to measure mechanical properties of endothelial primary cilia with the diameter of ca. 200 nm and the length of several micron existing on the cell surface and to identify them as a mechanosensor. We fabricated an in-house micro-tensile tester to measure mechanical properties of primary cilia and successfully obtained their Young's modulus. In addition, when calcium experiments were performed on the isolated primary cilia by tensile stimulation, an increase in calcium expression was observed in the primary cilia, indicating that calcium channels existing on the surface of primary cilia could activate the entry of calcium ion.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 18H03508

Dynamic characteristic evaluation and diagnosis of mechanical/biological systems by non-contact laser excitation system
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2016 - 31 Mar. 2019
Kajiwara Itsuro
This study developed a health monitoring system for detecting damage on structures. An approach for detecting a hole drilled on a pipe based on laser plasma acoustic excitation and acoustic measurement is included in the results of this study. Non-contact acoustic impulse excitation can be realized by laser-induced plasma and a microphone is used for measuring the time response of acoustic pressure. In this study, we focus on the detection of the hole on the pipe. The time response of acoustic pressure changes due to reflection of acoustic wave caused at the hole drilled on the pipe. The position of the hole is identified by applying continuous wavelet transform to measured time response data with/without the hole. This study demonstrated the effectiveness of the present damage detection method based on the acoustic excitation using the laser-induced plasma.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 16H04286

Development of novel microchannel device for cell migration with micropillar array
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
2013 - 2015
Ohashi Toshiro, Cooper-White Justin
Cell migration is known to play an important role in a number of physiological events in living body such as morphogenesis, wound healing, and tumor metastasis. It is therefore important to study the mechanism of cell migration from the viewpoint of mechanics. The objective of this study is to newly design and fabricate a multichannel device integrated with micropillar technology to evaluate cell traction forces during cell migration. The multichannel device has been successfully fabricated, which allows to modulate cell migration rate by changing the stiffness of micropillars and by giving the micropillars anisotropic properties.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 25560187

Clarification of signal transmission mechanism in mesenchymal cells during spontaneous cartilage regeneration induced by multi-functional synthetic gel
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
01 Apr. 2011 - 31 Mar. 2014
YASUDA Kazunori, OMIYA Yoshihiro, OHASHI Toshiro, KUROKAWA Takayuki, KITAMURA Nobuto, TANAKA Shinya, SEMBA Shingo
This study discovered several important phenomena and their molecular mechanisms during chondrogenic differentiation and regeneration of mesenchymal cells induced by the PAMPS/PDMAAm gel or soluble proteins:(1) ATP oscillation, which depends on oscillation of both the mitochondrial respiration and the glycolysis, was induced by calcium ion oscillation. The ATP oscillation does not control cell differentiation but controls cell aggregation and tissue formation via controlling secretion of soluble proteins. (2) Young's modulus of a chondrogenic precursor cell increased to a significantly greater degree during differentiation induced by the gel than during differentiation induced by Insulin. (3) Both the BMP-Smad signaling pathway and the IGF-depending signaling pathway were specifically activated during the differentiation induced by DN gel in comparison with that induced by Insulin. (4) The proteomics analysis showed that the gel has a function as a reservoir of soluble factors.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 23240070

Development of MEMS Devices with Microwell Slide for High Throughput Analysis of Cell Culture Experiment
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2012 - 2014
OHASHI Toshiro, MAEDA Eijiro, ANDERSSON-SVAHN Helene, COOPER-WHITE Justin
In this project, MEMS devices that allow to realize measurements and control of physical environment of cells were developed. The developed MEMS devices are for experiments of cell responses to mechanical environment, cell responses to chemical environment and cell migration. For the experiment of cell mechanical responses, it was confirmed to apply different level of fluid shear stress to endothelial cells cultured in a microwell to perform flow experiments. For the experiment of cell chemical responses, it was confirmed to apply different concentration of Saponin solution to endothelial cells to perform live/dead cell assay. For cell migration assay, mechanical characterization of fibroblast migration could be performed by using a micropillar array.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 24300157

Development of innovative biochip for controlling cell adhesion
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
2010 - 2012
OHASHI Toshiro, MAEDA Eijiro
This paper presents development of a technique to control cell adhesion usingan array of magnetic microbeads. Using MEMS techniques, we fabricated an array of microholes (3 μmin diameter and 2 μm in depth) on the surface of a glass substrate, to trap magnetic microbeads (2.8 μmin diameter) in the microholes. The magnetic microbeads were coated with fibronectin prior to theloading. A permanent magnet was placed under the substrate and was used to trap microbeads into themicroholes. After 24 hours incubation, it was observed that cells attached only to the magneticmicrobeads, but not to the other parts of the glass surface.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 22650097

Study of Mechanisms of Cellular Mechanosensing
Grants-in-Aid for Scientific Research Grant-in-Aid for Specially Promoted Research
2008 - 2012
SATO Masaaki, OHASHI Toshiro, KANNZAKI Makoto, DEGUCHI Shinji, SAKAMOTO Naoya, ADACHI Taiji, OGURA Toshihiko, OHASHI Kazumasa
There are many cells sensing mechanical forces in our body and the cells control the functions of tissues and organs to be adapted to mechanical environment. However, the mechanisms were not elucidated yet. In this study, we mainly focused on vascular endothelial cells, osteocytes and myocytes. It became clear that cell-cell and focal adhesions and cytoskeletons such as stress fiber are working as mechanosensors and some proteins in cytoplasm were identified as signal messengers. Mechanical forces were also playing important roles in organogenesis such as valve formation in cardiovascular system.
Japan Society for the Promotion of Science, Grant-in-Aid for Specially Promoted Research, Tohoku University, 20001007

Development of Bioassay System with Microwell Slide Towards High throughput Single Cell Analysis
Grants-in-Aid for Scientific Research(基盤研究(B))
2008 - 2010
Toshiro OHASHI, 佐藤 正明, 坂元 尚哉, Eijiro MAEDA, Masaaki SATO, Naoya SAKAMOTO
Since most laboratory bioassays used for cell analysis are designed to measure average effects on cell population, it is difficult to study characteristics of individual cells such as patient's tumor cell samples in a high throughput manner. Recently, a novel microwell slide that allows several thousands of single cells to be addressed to an exact position, cultured for weeks, and treated separately in high throughput has been developed. In this project we have proposed a bioassay system consisting of an active microfluidic device integrated on the microwell plate for improved control of, a...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 東北大学->北海道大学->東北大学->北海道大学, Principal investigator, Competitive research funding, 20300149

磁気駆動マイクロピラーによる細胞外局所力学環境のアクティブ操作
科学研究費補助金(特定領域研究)
2008 - 2008
大橋 俊朗, 佐藤 正明, 坂元 尚哉
生体内において細胞は力学環境に曝されている. 例えば, 血管内皮細胞や平滑筋細胞には血流によるせん断応力や血管拡張に伴う伸展刺激が作用している. 細胞はこのような周囲の力学環境に適応して自らの形態および物質産生等の機能を変化させることが知られている. これは細胞が力学刺激を感知・伝達し生化学的信号に変換しているためであり力学情報伝達(mechanotransduction)と呼ばれている. 申請者らはこれまでに, 力学情報伝達の経路の一つに細胞骨格が深く関与していると考え力学刺激に対する内皮細胞や平滑筋細胞の骨格構造変化を観察してきた. このような中, 申請者らはマイクロピラーを有する基質の上に平滑筋細胞を培養し, マイクロピラーの撓み細胞牽引力を計測することで細胞内の力学情報伝達経路を探る研究に本格的に着手した. 例えば, ガラスのマイクロニードルで細胞辺縁部の特定のマイクロピラーを撓ませると, ストレスファイバーによって接続されていた他端のマイクロピラーが撓むことから細胞骨格を介した力学伝達が実現されていることを確認した. 研究を遂行していく中で, この技術を応用し任意のマイクロピラーを能動的に動かすことができれば特定の焦点接着斑にのみ選択的に力学刺激を負荷できるのではないかと考えた. そこで本研究課題では, 従来の研究をさらに発展させ, 磁性ビーズを埋入したマイクロピラ...
文部科学省, 特定領域研究, 東北大学, Principal investigator, Competitive research funding, 20034007

細胞内シグナル伝達の動的制御による細胞マイクロマシンの創出
科学研究費助成事業 萌芽研究
2007 - 2008
佐藤 正明, 大橋 俊朗, 坂元 尚哉
本研究の目的は,分子スイッチをコートした磁気ビーズを細胞内に導入し,これを外部から磁場を印可することによって任意に操作し,細胞の仮足形成を任意に操作し,細胞運動を制御するところにあった。研究第一段階として,細胞内での磁気ビーズ操作に必要な磁気ピンセット装置の開発を行った。より自由度の高い操作を実現する為,電磁石駆動型の装置を開発し,電源のON/OFFによって磁場のコントロールが可能な系とした。また,持続的な操作を可能とするため,電磁コイルの冷却装置を実装した。第二段階として,細胞内に食作用によって導入した磁気ビーズを,実際に細胞内で空間的に操作することを試みた。細胞内に導入された複数個の磁気ビーズを任意の位置(細胞辺縁部)へと集積させることに成功した。また,共焦点レーザー顕微鏡を用いたリアルタイム三次元観察によって,ビーズ操作が細胞膜内で行われていることも確認された。次に,分子スイッチをコートしか磁気ビーズを作製し,細胞内への導入を試みた。当初は細胞のエンドサイトーシス作用などを用いる予定であったが,この手法では磁気ビーズが細胞内でエンドソームなどのリン脂質に包まれた状態となってしまう為,分子スイッチが機能しなかった。そこで,物理的外力によって細胞内に微粒子を撃ち込むパーティクルガン装置によって磁気ビーズの導入を試みた。磁気ビーズを本手法によって導入すること自体には成功したものの,本来,当該装置は植物細胞に金やタングステンなどの比重の大きい微粒子を撃ち込む装置であり,本研究では動物細胞および比重の軽い磁気ビーズを用いることから,実験条件が大きく異なるため,これまでのところ細胞に与えるダメージを十分低減させて導入するまでには至っておらず,導入条件を検討中である。
日本学術振興会, 萌芽研究, 東北大学, 19650111

マイクロポストを用いた細胞の形態制御と力学伝達経路の解明
科学研究費補助金(萌芽研究)
2006 - 2008
大橋 俊朗, 佐藤 正明, 坂元 尚哉
細胞の力学情報伝達は細胞の生理・病理に深く関わることからそのメカニズムを知ることは重要であるが, 力学刺激が実際に細胞内でどのように伝達されているか, またそれによって機能がどのように修飾を受けるのかに関しては未知の部分が多い. 本研究では, 微細加工技術により細胞底面に発生する力を計測できる実験系を構築し, 基質形状により細胞の形態を制御すること, さらに力学刺激が細胞骨格を伝達する経路を求めることを目的とする. 微細加工技術を用いて細胞を培養するマトリックス上にPDMSによるマイクロピラーアレイ(高さ10μm, 直径3μm, ピラー間ピッチ8μm)を形成し, マイクロピラーのたわみから細胞底面で発生する牽引力を計測するものである. 本年度においては, 前年度に引き続き細胞形態制御実験, マイクロピペットによる力学環境操作実験, 細胞骨格の破壊実験を行い, データの蓄積を試みた. 細胞形態制御実験では, ピラー間ピッチを6, 8, 10μmと変化させ, 細胞はピラー間ピッチに依存して牽引力を変化させることを示した. マイクロピペットによる力学環境操作実験ではより精度良くマイクロピラーによる局所力学刺激負荷を行うため磁気駆動式マイクロピラーの製作にとりかかっているところである. 細胞骨格の破壊実験では, アクチンフィラメント, 微小管, 中間径フィラメントそれぞれの破壊により...
文部科学省, 萌芽研究, 東北大学, Principal investigator, Competitive research funding, 18650119

マトリックスデバイスによる細胞骨格の力学バランス計測と細胞機能制御
科学研究費補助金(特定領域研究)
2006 - 2007
大橋 俊朗, 佐藤 正明, 坂元 尚哉
細胞の力学情報伝達は細胞・組織の生理・病理に深く関わることからそのメカニズムを知ることは非常に重要であるが,力学刺激が実際に細胞内でどのように伝達されているか,またそれによって機能がどのように修飾を受けるのかに関しては未知の部分が多い.本研究では,マイクロマシニング技術により細胞底面に発生する力を直接計測できる実験系を構築し,力学刺激が細胞骨格を伝達する経路およびその大きさを定量的に求めること,さらにこの実験系により機能制御の実現可能性を探ることを目的とする.微細加工技術を用いて細胞を培養するマトリックス(細胞外基質)上にPDMSによるマイクロピラーアレイ(高さ10μm,直径3μm,マイクロピラー間ピッチ8μm)を形成し,マイクロピラーのたわみから細胞底面で発生する牽引力を計測するものである.本年度において,先端径が2〜3μm程度のガラスのマイクロピペットをマイクロマニピュレータで操作し,特定のマイクロピラーを強制的にたわませる実験を行った.その結果,たわませたマイクロピラーに接続しているストレスファイバの他端のマイクロピラーが連動してたわむ様子が観察された.すなわち,ストレスファイバを通して一つの焦点接着斑からもう一つの焦点接着斑に力学刺激が伝達されていることが明らかとなった.また,ノコダゾール処理により微小管を破壊したところ牽引力は有意に増大した.一方,微小管破壊によりス...
文部科学省, 特定領域研究, 東北大学, Principal investigator, Competitive research funding, 18048005

Study of roles of cytoskeletons in morphological responses of vascular endothelial cells to mechanical stimuli
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2005 - 2007
SATO Masaaki, OHASHI Toshiro, DEGUCHI Shinji, SAKAMOTO Naoya
1) Evaluation of mechanical property of stress fibers
Mechanical properties of stress fibers extracted from smooth muscle cells (SMCs) and endothelial cells (ECs) were measured with a microneedle-based tensile test system developed in this study. Strain-induced stiffening was observed in the force-strain curve. We also found that the extracted SFs shortened to approximately 80% of the original length after they were dislodged from the substrate, suggesting that SFs had preexisting strain in the cytoplasm. The force required for stretching the single SFs from the zero-stress length back to the original length was approximately 10 nN for SMCs and 4.1 nN for ECs.
2) Measurement of traction forces of cells using microfabricated micropost arrays
A mold of silicon substrates with arrays of micro-needle-like posts (3μm in diameter, 10μm in height, and 8μm intervals) was fabricated to estimate cellular traction forces using microfabrication techniques. SMCs spreading on the substrates produced deflection of the posts and was associated with organization of stress fibers of actin filaments. Traction forces varied considerably among cells, showing an average of approximately 12 nN.
3) Cyclic stretch test with microsubstrates
We applied cyclic stretch to ECs using a microstructured substrate with arrays of micropost, on which cells were selectively stretched between FAs but FA-substrate contact area were hardly stretched. After exposure ECs to cyclic stretch for 3h, cells on both a flat and the micropost substrates aligned perpendicular to the direction of stretch. Stress fibers oriented about 60° to the stretch direction for the flat substrate at 3h, while stress fibers on the micropost substrate oriented approximately 90° to the stretch direction after 6h stretching. These results suggest that strain in FA-substrate contact area may have impact on rates of reorienation of stress fibers in ECs in response to cyclic stretch.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Tohoku University, 17200030

細胞内マルチイメージングを用いた力学応答シグナル伝達機構の解明
科学研究費補助金(若手研究(A))
2005 - 2007
大橋 俊朗
細胞の力学情報伝達機構を知ることは細胞の生理・病理を知る上で非常に重要である.力学刺激が実際に細胞内でどのように伝達されているかに関してはその計測の困難さからほとんど解明されていない.本研究では細胞内で力学刺激が伝達していく過程を明らかにするため,ピペット吸引法とFRAP技術を組み合わせて力学刺激に対する細胞骨格構造の変化を蛍光画像として追跡し画像解析により細胞内の力学環境を定量的に把握することを目的とする.またセカンドメッセンジャーの一つであるカルシウムイオン濃度の変化を同時にイメージングすることにより骨格構造変化との相関関係を調べる.本年度においては,FRAP技術を用いてピペット吸引時の軟骨細胞におけるアクチン分子の拡散の様子を詳細に調べた.その結果,ピペット先端において吸引直後はアクチンコーティカルレイヤーが分解され,その後,アクチンの再重合が促進されていることがわかった.また,このプロセスはカルシウム依存でありカルシウムが存在しない場合には,アクチンの脱重合が引き起こされにくいことが示唆された.さらに,ピペット吸引時において力学刺激が細胞内をどのように伝達していくのかを観察するために,ミトコンドリアの染色画像より画像相関法を用いて細胞内ひずみ分布を得た.その結果,吸引直後は細胞周囲のアクチンコーティカルレイヤーを介して細胞全体に力学刺激が伝達される様子が明らかとなった...
文部科学省, 若手研究(A), 東北大学, Principal investigator, Competitive research funding, 17680036

Biomechanics at Micro- and Nanoscale Levels
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas
2003 - 2007
WADA Hiroshi, ADACHI Taiji, MASTUMOTO Takeo, USHIDA Takashi, TANAKA Masao, OHASHI Toshiro
本研究では平成15年度から18年度まで実施した特定領域研究「マイクロ・ナノバイオメカニクスの開拓」の成果を学術図書として取りまとめた.本特定領域研究の目的を以下に記す.生命現象の本質的な多様性は,遺伝子のみではなく,細胞をめぐるマイクロあるいはナノスケールの構造と遺伝情報との相互作用によって担われており,その中でも,力学的相互作用の意義は極めて大きい.従って,力学的環境と生命機能の関係を解明することができれば,細胞及び組織の構造と機能をコントロールする手段を見いだせる可能性が高い.また,これを用いることによって,必要な構造と機能をもつ細胞と組織を創成することが可能となる.そこで,力学を基礎とし,マイクロ領域である細胞レベル及びナノ領域である生体高分子や細胞内小器官レベルの力学現象を解明し,これに基づいて人工材料の新たな設計指針の開発と創製を行うと共に,生命体の機能と構造を創成ないし再構成する技術を開発してきた.日本の生体工学・バイオメカニクス研究を牽引する研究者を各計画研究の代表者として集め,バイオメカニクス的視点を強く打ち出し,細胞や生体組織の再構築との関連性ならびに基礎科学から臨床応用までの広い視点をもった研究を展開し,世界一級の成果を上げて来たので,これら成果を取りまとめた.具体的には以下を行った.
1. 第10回全体会議(平成19年10月,東京)ならびに第11回全体会議,(平成20年1月,東京)を開催し,研究グループの研究成果に関する情報交換を行った.
2. 本領域の4つの班毎に,研究成果を取りまとめた.
3. 4班の成果を統合し,全体にわたった構成を4班の代表者4名により取りまとめた.
4. 出版社との打ち合わせを行い,全体の原稿を完成した.
5. 印刷原稿の校正を各研究代表者が行った.
6. 印刷製本を業者に委託し,学術図書を完成させ,研究成果を広く公開した.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Priority Areas, Tohoku University, 15086101

細胞内ストレスファイバの力学特性計測と変形機構の解明
科学研究費助成事業 萌芽研究
2005 - 2006
佐藤 正明, 大橋 俊朗, 出口 真次, 坂元 尚哉
細胞の形態変化と機能を理解する上で,主要な構成要素であるストレスファイバの力学環境に対する応答性,すなわち力学特性を把握しておくことは大変重要である.最終年度である本年度は,前年度に開発・確立した装置およびストレスファイバ単離手法を用いて以下の2つの研究を行った.
1.ストレスファイバの粘弾性特性の計測
前年度確立した単離方法に従って平滑筋細胞から単離したストレスファイバの引張試験を行い,ひずみ速度が引張特性に与える影響を調べた.ひずみ速度を0.01s^<-1>,0.05s^<-1>,0.1s^<-1>と設定しストレスファイバの引張特性計測を行ったところ,0.01s^<-1>と0.05s^<-1>における張力ーひずみ関係はほぼ線形で両者に顕著な差は見られなかった.一方,生理的なひずみ速度と考えられる0.1s^<-1>では上に凸の非線形な関係が得られた.またストレスファイバの変形初期の強度を示す初期スティフネスに関しても0.1s^<-1>では0.01s^<-1>および0.05s^<-1>に比べ大きくなる傾向が得られた.これらの結果から,ストレフファイバの引張特性にはひずみ速度依存性の閾値が存在する可能性が考えられた.
2.ストレスファイバの局所ひずみ計測
量子ドットを用いてストレスファイバを斑点状に可視化し,これをマーカーとして伸展時におけるストレフファイバ内の局所挙動を観察した.その結果,ストレフファイバは一様に伸展しているのではなくその挙動は局所で異なり,部位によって収縮を示す場合があることが明らかになった.
日本学術振興会, 萌芽研究, 東北大学, 17650125

Mechanical dynamics of focal adhesions of vascular endothelial cells using nano-imaging
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas
2003 - 2006
SATO Masaaki, OHASHI Toshiro, DEGUCHI Shinji, SAKAMOTO Naoya
The goal of this project is to study dynamics of FAT domain in focal adhesions and associated actin filaments in order to understand remodeling process of adherent cells in response to external mechanical stimuli. In particular, newly developed experimental techniques here include a time-course observation of dynamics of FAT domain and actin filaments under application of fluid flow and a stretching system using an elastic membrane with nonuniform surface structure. First, we have developed an experimental system which enables to observe dynamics of cells using RFP-conjugated FAT-domain vector and GFP-conjugated actin vector. The result showed that actin filament structure was reconfigured in a close association with appearance/disappearance of FAT domain. Second, PDMS membrane with an array of micropillars has been fabricated by using soft lithography technique to locally apply stretching between focal adhesions. Endothelial cells formed focal adhesion complexes at peripheries of the top of the micropillars and developed stress fibers, thick actin bundles, perpendicular to the direction of stretch. Finally, we have developed a micro-tensile tester to measure mechanical properties of stress fibers, which would be critical for understanding of intracellular stress transfer. Tensile tests were, for the first time, carried out on stress fibers chemically isolated from endothelial cells, providing a load-displacement relationship. It was found that the load-displacement curve was nonlinear with high extensibility. We have successfully studied important roles of cytoskeletons and focal adhesions of mechanically stimulated cells in intracellular force transmission mechanism.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Priority Areas, Tohoku University, 15086203

ナノマシン加工技術による内皮細胞焦点接触力の計測デバイスの開発
科学研究費助成事業 萌芽研究
2003 - 2004
佐藤 正明, 坂元 尚哉, 大橋 俊朗
細胞は細胞外基質と焦点接着斑と呼ばれるタンパク質の塊状部位によって接触を実現し形態を維持していると考えられている。従って力学的刺激あるいは化学的刺激に対する細胞の応答を知る上で焦点接触力を計測することは重要である。本研究では,シリコンの微細加工技術を用いて微小なセンサを開発し細胞の焦点接触力を測定することを目的とする。最終年度である今年度は,初年度に目指していたピエゾ抵抗型センサ方式を変更し,マイクロポストのたわみから接触力(牽引力)を推定する方式を検討した。まず,アレイ状マイクロポストのデザインを起こしレチクルを製作した。次にシリコンウェハにレチクルのデザインを露光転写した。ウェハをエッチングしレジストを剥離して型を製作した。続いて型にシリコーンポリマーを流し込みカバーガラスを載せた後,加温硬化させた。硬化後,型からカバーガラスごとシリコーンポリマーをはがし細胞外基質を完成させた。マイクロポストのサイズはおよそ直径3μm,高さ10μm,中心間距離8μmである。試料として,当初の予定であった内皮細胞よりも骨格構造により特徴のある平滑筋細胞を用いた。製作した基質上に平滑筋細胞を培養しマイクロポストのたわみを画像処理によって求めた。焦点接着斑の位置を確認し,かつアクチンフィラメントとの関係を把握するために,RFP-FATとGFP-アクチンのベクターを細胞に導入した。その結果,推定された平滑筋細胞の牽引力は11.8nNであり,最大値は81.3nNであった。また,それストレスファイバの分布から推測される力の合成ベクトルと牽引力のベクトルの方向は明らかに一致していた。このことからストレスファイバの発達は細胞の牽引力に支配的であることが考えられた。以上のように,本研究ではマイクロポストを有する細胞外基質デバイスを製作し,細胞底面に発生するミクロな力学環境を解明することに成功した。
日本学術振興会, 萌芽研究, 東北大学, 15650085

Study of the Effect of Hemodynamic Forces on Mechanism of Atherogenesis using Cocultured Blood Vessel Model
Grants-in-Aid for Scientific Research(基盤研究(B))
2003 - 2004
大橋 俊朗, Naoya SAKAMOTO, 坂元 尚哉, Masaaki SATO
This project investigated the mechanism of development of atherosclerosis using endothelial-smooth muscle cell (EC-SMC) cocultured blood vessel model and obtained the following results.1.Migration of SMCs in the cocultured blood vessel models increased about 1.8 times higher than that in the model constructed with SMCs only. Exposure the cocultured model to fluid shear stress resulted in suppression of SMC migration. The migration of SMCs was not decreased by exposure to shear stress with medium containing an inhibitor of nitric oxide (NO) synthase. Theses results indicate that EC derived N...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 東北大学, Principal investigator, Competitive research funding, 15300153

Roles of Integrins of Endothelial Cells in Response to Mechanical Stimuli
Grants-in-Aid for Scientific Research
2002 - 2004
SATO Masaaki, HANE Kazuhiro, MATSUMOTO Takao, OHASHI Toshiro, SAKAMOTO Naoya, DEGUCHI Shinji
In order to elucidate the response mechanisms of endothelial cells to mechanical stimuli, dynamic changes in actin filaments and integrins were precisely observed using confocal laser scanning microscopy. Shear stress, membrane tension of substrate and hydrostatic pressure as mechanical stimuli were applied to cultured endothelial cells and the following conclusions were obtained.
1.GFP-actin and RFP-FAT (focal adhesion targetting) vectors were transfected into cultured endothelial cells that were used to impose to shear stress. Actin filament was suggested to sense the tension and occur the dynamic changes as the first step. Secondly the lamellipodia were formed. During this process, it was suggested that the movement and allocation of integrins are possible to be controlled through microtubules.
2.Endothelial cells were cultured on silicone membrane in which a cover glass was immersed to form heterogeneous strain distribution. A cell was exposed to non-uniform strain and showed that distribution of actin filaments and the location of nucleus was dependent on the strain distribution. It was suggested that the cell is able to sense mechanical stress and respond so as to keep the mechanical balance in the cell.
3.We have reported the cultured endothelial cells respond to the hydrostatic pressure and show multilayering, cell elongation with no predominant orientation and characteristic distribution of actin filaments. To elucidate the mechanisms, we have focused on expression and distribution of VE-cadherin as an important protein to adhere the cells. It was suggested that the hydrostatic pressure has important effect on the expression of VE-cadherin.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Tohoku University, 14208100

Measurement of mechanical properties of vascular smooth muscle cells as a model of functional materials
Grants-in-Aid for Scientific Research
2001 - 2003
MATSUMOTO Takeo, NAGAYAMA Kazuki, OHASHI Toshiro, SATO Masaaki
Vascular smooth muscle cells not only change blood vessel diameter through their contraction and relaxation, but also remodel blood vessel wall by producing extracellular matrices such as collagen. Their contractile properties and matrix synthesis change in response to the mechanical stimuli applied to them : For example, their contractile velocity increases with repetitive contraction, and the energy necessary to maintain their isometric contraction decreases when the cells are kept contracted. Thus, the smooth muscle cells have interesting characteristics as a functional material. In this three-year study, we have examined the mechanical properties and the contractile properties of the vascular smooth muscle cells in a single cell level to clarify their relationship with the mechanical stimuli. In the first year, we found that the elastic modulus of the smooth muscle cells isolated from the hypertensive rat thoracic aorta was about one half of that of the normotensive aorta. In the second year, we found that the elastic modulus of the smooth muscle cells obtained from the rabbit thoracic aorta increased by the factor of 10 when they got contracted. In the last year, we examined the relationship between the tensile properties of the cell and the amount of their intracellular actin filament : We first measured the tensile properties of the smooth muscle cells freshly isolated from the normotensive rat thoracic aortas (FSMCs) and those of the cultured cells of the same origin (Passage 4-9, CSMCs). Then, we stained the cells with rhodamine-phalloidin for actin filaments to know the difference in the actin filament amount between the FSMCs and the CSMCs. The initial elastic modulus of the cells was about 11 kPa (N=8) for FSMCs and about 2.6 kPa (N=10) for CSMCs. The actin filaments in the FSMCs were abundant in the cytosol and it was hard to distinguish each filaments, while in the CSMCs, the filaments were sparsely distributed and stress fibers are clearly distinguishable, indicating that the decrease in the actin filament amount in the CSMCs. Such difference in the actin filament amount may cause the difference in the mechanical properties of the cells. We should analyze quantitatively the relationship between the actin filament amount and the mechanical properties in the next study.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), 13450040

構造最適化手法を用いた流れ負荷培養内皮細胞における骨格構造の再構築メカニズム
科学研究費補助金(奨励研究(A), 若手研究(B))
2001 - 2002
大橋 俊朗
本研究では流れ負荷培養内皮細胞のアクチンフィラメントが再構築される過程をリアルタイムで観察し,同時に有限要素法解析を行い細胞の力学応答のメカニズムを解明することを目的とする.平成14年度では以下の成果を得た.昨年度用いたGFP-アクチン融合ベクタに加えて,本年度はRFP-FAT融合ベクタを遺伝子導入した.FATとはFocal Adhesion Targetingの略称であり,これにより細胞底面の焦点接着斑の挙動を観察できるため,アクチンフィラメント挙動と併せて内皮細胞の力学応答をより詳細に観察できる.これらの遺伝子を培養ウシ内皮細胞に遺伝子導入し,流れによるせん断応力を5時間にわたって負荷し,共焦点レーザ顕微鏡によりアクチンフィラメントおよび焦点接着斑の挙動を経時的に観察した。その結果,接着斑は流れの方向へ配向し,アクチンフィラメントの収縮に伴い移動する様子が観察された.また,焦点接着斑の間を連結するようにアクチンフィラメントが新たに形成されていく様子も観された.以上のことより,接着斑とアクチンフィラメントの相互関係が流れ負荷内皮細胞の形態変化に深く関与していることが示された.また,細胞骨格構造を模擬した有限要素モデルを構築した.成長の構成則に代表される構造最適化のアルゴリズムを導入して計算を行った結果,実験結果と同様に流れ負荷後,細胞の高さは減少傾向を示し。流れ負荷に伴い流...
文部科学省, 奨励研究(A), 若手研究(B), 東北大学, Principal investigator, Competitive research funding, 13780667

Development of a cell rotation sytem for the observation of 3D microstructure of cells
Grants-in-Aid for Scientific Research
2000 - 2002
MATSUMOTO Takeo, OHASHI Toshiro, SAIO Masaaki
A cell rotation system has been developed to observe the 3D miciostructure of cells precisely from their images obtained from various view points. In this system, a specimen cell is held with a micropipette by aspirating the cellular surface gently under an upright microscope with water immersion objectives, and is rotated around the axis of the micropipette which is set perpendicular to the optical axis of the microscope. The pipette was mounted on a 3D electric micromanipulator and the position of the pipette tip was controlled based on its image taken with a CCD video camera mounted on the microscope. The pipette tip was coated with black ink and the tip position in the focusing (X-Y) plane was determined by binarization of the tip image. The tip position signal was fed to a comparator controlling the micromanipulators in X and Y direction. The pipette tip was kept focused with a PID controller maintaining the binarized area of the pipette tip minimum by changing the Z position of the pipette. Cultured bovine thoracic aortic smooth muscle cells were stained with SYTO13 for their nucleus and DiI for their cellular membrane and attached to the micropipette tip. Pan-focus images were constructed from optical sections across a cell at every 9° from 0° to 18° . The three-dimensional images of the cell nucleus and the cell membrane were obtained from these pan-focus images. These reconstructed images indicated that the nucleus of the cell detacher from the substrate wirth trypsin was round in shape, while that of the cell fixed with formalin on the substrate was elongated and flattened. The present method for the reconstruction of the cell microstructure with the cell rotation system would be useful for quantitative 3D analysis of the cell morphology.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), 12558101

魚の側線感覚細胞はせん断速度センサとなりうるか?
科学研究費助成事業
2000 - 2001
佐藤 正明, 大橋 俊朗, 松本 健郎
魚類や円口類(ヤツメウナギなど)の体の両側にある側線は音を感じるセンサであることはよく知られている.また,このセンサは魚などのまわりの水の動きに反応しているのではないかという考えが提案されているが,このような観点からの研究例はほとんどない.もし,水の動きを感じることができるとすれば,流れのせん断応力あるいはせん断速度を計測可能なセンサとして利用可能になる.そこで,本研究では魚などの側線に存在する感覚細胞を取り出して培養し,流れ負荷の状態で魚の感覚細胞の特性を明らかにし,その応用についても議論することを目的とする.
これまで報告されている感覚細胞を使った研究ではカジカが利用されているが,本研究ではカジカが入手困難のため金魚を使い,次の結果を得た.
1.金魚の側線感覚細胞の存在する部位から組織を切り出し,Ca^<2+>,Mg^<2+>を含まないハンクス液にコラゲナーゼとエラスターゼを含む溶液を作製して,組織を処理した.種々の濃度の組み合わせにより検討した結果,最適の濃度を見いだし,側線感覚細胞を単離することができた.単離後,細胞活性をトリパンブルーにより観察したところ,特に強い傷害も受けていないことを確認した.
2.感覚細胞を通常の細胞培養液中にて培養を試みたところ,2〜3日の培養は可能であるが,その後は急速に細胞活性を失っていくことを確認した.
3.感覚細胞をゲル中に包埋してせん断応力を負荷する装置にセットし,流れ負荷をかける実験を試みたが,細胞の活動度を電極を用いて定量的に評価する計測までには至らなかった.今後はこの点を中心に検討を進める予定である.
4. せん断応力負荷時の側線細胞の応答機構について有限要素法を用いて解析し,細胞内の変形と応力分布を得た.今後細胞内構造と応力分布の関係を検討する予定である.
日本学術振興会, 萌芽的研究, 東北大学, 12878164

Development of Atomic Force Microscope System Combined with Confocal Laser Scanning Microscope to Simultaneously Measure Mechanical Stiffness and Observe Microstructure of Cultured Cells
Grants-in-Aid for Scientific Research
2000 - 2001
SATO Masaaki, OHASHI Toshiro, MATSUMOTO Takeo
Under flow condition endothelial cells are elongated and oriented to flow direction depending upon the level of shear stress and the duration of exposure. It is well known that cytoskeletal components, especially F-actin filaments, are playing important roles in the process of adaptation of cell shape to mechanical environment. In this project We have mainly focued two topics and obtained the results shown below.
1. Dynamic behavior of actin filament in living cells
We observed dynamic behavior of actin filaments in living cultured endothelial cells during exposure to shear stress. To do this, a vector of a green fluorescent protein (GFP)/actin fusion was introduced into cells using a lipofectoamine. Dynamic behavior of actin filament in an endothelial cell after introducing cytochalasin D was observed through CCD camera under an inverted fluorescent microscope. In different experiments, the endothelial cells were exposed to fluid shear stress of 2 Pa in a parallel plate flow chamber and the cytoskeletal structure was observed. Actin filaments located first at peripheral regions seemed to change the alignment after flow exposure and aligned to a long axis of the cell, which was not oriented to the flow direction yet, but already elongated.
2. Stress analysis in a cell exposed to shear stress
A fluid flow-structural analysis, i.e. a coupled field analysis, was performed to simulate three dimensional stress distribution in endothelial cells exposed to shear stress. The three-dimensional finite element model was generated on the basis of the cell surface geometry measured by an atomic force microscopy. The model consisted of a fluid element and a solid element representing the flow field and the endothelial cells, respectively. Analytical results on stress distribution in the cell showed that high compressive stress appeared both in the upstream side and the downstream side. These results may indicate that the stress distributions in the cells have close correlation with the F-actin distributions.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Tohoku University, 12480257

Measurement of intramural stress and strain distributions in the atherosclerotic arteries considering the complexity of the lesion
Grants-in-Aid for Scientific Research
1999 - 2000
MATSUMOTO Takeo, OHASHI Toshiro, SATO Masaaki
To reveal the effects of mechanical factors on the initiation and progression of atherosclerosis, it is important to know the stress and strain distribution in the atherosclerotic lesions as well as the effects of blood flow on the endothelial cells. In this 2-year project, we experimentally induced atherosclerotic lesions in the rabbit thoracic aortas and studied the mechanical environment of the atherosclerotic lesions by measuring their local mechanical properties and local defomation of the aortas during inflation. We first measured local elastic modulus by a pipette aspiration method and studied the relationship between the modulus and the histology quantitatively to find that the atherosclerotic tissue became softer than the normal tissue at the initial stage of the lesion, then became stiffer with the appearance of the smooth muscle cells and calcified tissues. Next, we measured the deformation of the tubular specimen of the aortas during inflation as follows : We made four fine needles penetrate through the wall at an angular interval of about 90゜ as markers and observed the displacement of the needles during inflation from an end of the specimen. Local deformations of the wall were obtained at four circumferential segments held with the two adjacent needles. Strain referring to the stress-free state was obtained for each segment. The strain was not uniform among the segments in the atherosclerotic aorta. The difference among the segments tended to increase with the progression of the disease. Similar measurement performed for human coronary arteries indicated that the segment with thicker plaque had smaller strain. These results indicate that atherosclerotic arteries show marked heterogeneity. Local measurement is indispensable to reveal the mechanical environment of atherosclerotic lesions.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Tohoku University, 11680834

STUDY OF ULTRA-FINE STRUCTURED OPTICAL COMPONENTS USIING MICROMACHINING
Grants-in-Aid for Scientific Research
1998 - 2000
HANE Kazuhiro, SASAKI Minoru, ESASHI Masayoshi
We proposed a fabrication technique for sub-wavelength grating using electron-beam drawing machine and fast atom beam etching machine. On the surface of nonconductive optical glass, 150nm period surface gratings were fabricated. The etching of the nonconductive surface was carried out by using advantageously the neutral fast atom beam instead of ions in the conventional etching plasma. Without charging the surface, the deep etched profile with high aspect ratio was obtained. Using the proposed method, the reflection from the optical glass surface was suppressed considerably.
A program for calculating the rigorous electro-magnetic field in sub-wavelength grating was developed. It was revealed that the reflection properties were influenced very much by the period and aspect ratio of the gratings.
Using porous alumina membrane as a mask, the sub-wavelength gratings having 100nm period and the aspect ratio of 6 were fabricated on Si substrate. In the wavelength region from 370nm to 800nm, the superior properties for anti-reflection were obtained. Moreover, sub-wavelength gratings were also fabricated on the surface of the gallium arsenic light emission diode. Using the etching property of GaAs, tapered profile of surface grating was fabricated and a increase of the light emission was successfully obtained. In addition, the combinations between the surface gratings and micro-actuators were also investigated.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), TOHOKU UNIVERSITY, 10305020

Cell structure and mechanobiology　　　　　　　　　　　　　　　
2000
Competitive research funding

細胞の構造とメカノバイオロジーに関する研究　　　　　　　　　　　　　　　
2000
Competitive research funding

Development of Atomic Force Microscope System Combined with Confocal Laser Scanning Microscope to Simultaneously Measure Mechanical Stiffness and Observe Microstructure of Cultured Cells
Grants-in-Aid for Scientific Research
1998 - 1999
SATO Masaaki, HAYASHI Yoshiaki, OHASHI Toshiro, MATSUMOTO Takeo, KATAOKA Noriyuki
The atomic force microscope (AFM) system was originally developed in combination with an inverted confocal laser scanning microscope to simultaneously measure mechanical stiffness and to observe microstructure of cultured cell. To detect an indentation depth of the cantilever, a cantilever moving system was introduced. A special specimen holder was made to hold a commercially available culture dish. The movements of the cantilever and the specimen holder were controlled by a personal computer. This system was applied to statically cultured and shear stress exposed endothelial cells, and the following results were obtained.
1. Observation of actin filaments and measurement of three dimensional configuration were performed for a fixed endothelial cell.
2. Input and output (I/O) ports of culture medium were newly designed to use a culture dish for flow exposure experiments. Morphology and mechanical properties of cultured endothelial cells were measured using the AFM system. Endothelial cells cultured at static condition had a polygonal shape and more soft mechanical properties around a nucleus than those at peripheral regions. The stiffness of the endothelial cells exposed to shear stress of 2 Pa became higher with the duration time of exposure. Cell shape became elongated to the flow direction and the location of a nucleus moved to downstream side by shear flow.
3. A fluid flow-structural analysis was performed. The three-dimensional finite element model was generated on the basis of the cell surface geometry measured by the AFM. The model consisted of a fluid element and a solid element representing the flow field and the endothelial cells, respectively. Analytical results on stress distribution in the cell showed that high compressive stress appeared mainly in the upstream side. This result may indicate that the stress distributions in the cells have close correlation with the F-actin distributions.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), TOHOKU UNIVERSITY, 10558126

Biomechanical Analysis of Aortic Aneurysm Failure to Find Out the Important Factors
Grants-in-Aid for Scientific Research
1998 - 1999
SATO Masaaki, SADAHIRO Mitsuaki, MATSUMOTO Takeo, TABAYASHI Koichi, AKIMOTO Hiroji, OHASHI Toshiro
The aim of this project are to obtain mechanical properties of aneurysmal wall in vitro, to noninvasively measure the three dimensional shape of aneurysms for patients from MRI images, and to make models to predict the dangerous regions for aneurysm failure from the motion and stress analyses of aneurysmal wall. The following results were obtained.
1. The specimen excised form the aneurysmal region of patients was used for the biaxial tensile testing. The machine was newly developed in our laboratory. The diseased specimen from aneurysm was stiffer than normal tissues. The specimens with the higher elastic moduli were the higher anisotropic mechanical properties.
2. Three dimensional finite element model was successfully composed from MRI images for human thoracic aortas. In this model, the aortic wall was assumed to be thin membrane, isotropic, large linear deformation between diastolic and systolic pressures. The stress concentration was found in the frontal and dosal sides of aortic arch where aneurysm formation is frequently observed. Further, the location and shapes of the aneurysm had important and significant effects on the highest stress values and the stress distribution.
3. The strain and stress were calculated around the aneurysm of patients by measuring the deformation of aortic wall in MRI images. The results showed us that the strain was large around the frontal walls of aortic arch in healthy normal person. In aneurysmal patients, the large deformation to the outer wall side around the aneurysms was observed.
According to the present results, we will develop the new system to rapidly construct the finite element model from the MRI images and study more precise mechanical properties of aneurysmal walls.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), TOHOKU UNIVERSITY, 10480241

生体光情報計測のための近接場光学プローブの開発と評価
科学研究費補助金(奨励研究(A))
1998 - 1999
大橋 俊朗
近年,生物フォトンと呼ばれる超微弱光が注目されてきた.この生物フォトンが計測できれば新たな生体情報として非常に有用である.そこで,本研究では生物フォトンを効率よく検出するために微細加工技術を用いて微小なプローブを開発することを目的とする.この計測は近接場顕微鏡の原理を応用したもので,生体表面上のフォトンを微小プローブによって散乱させ,プローブ先端からフォトンを集めるものである.まずシリコンの微細加工技術により微小プローブを製作するために,有限要素法解析(FEM)により片持ち梁およびねじれ梁の振動特性を理論的に解析した.その結果,ねじれ梁は高次のモードを排除できるが片持ち梁の方が同程度の形状を有する場合,共振周波数は高い値を示した.次にフォトリソグラフィー技術により単結晶シリコンの微小プローブを製作した.製作した微小プローブの周波数特性はLC共振回路による容量センサおよび発信器から構成される実験装置によって測定を行ない,FEM解析結果とよい一致を示すことを確認した.この微小プローブを原子間力顕微鏡(AFM)のプローブとして用いれば細胞の表面形状とともにフォトンが検出できる.そこで第一段階として実際にウシ大動脈由来血管内皮細胞を用いて細胞表面形状を測定した.また,微弱光を検出するためのフォトダイオードの製作を併せて行なった.n型のシリコン基板にp型のボロンイオンを打ち込むことでp...
文部科学省, 奨励研究(A), 東北大学, Principal investigator, Competitive research funding, 10780526

Development of a micro tensile tester for the in-process monitoring of cell structure
Grants-in-Aid for Scientific Research
1997 - 1999
MATSUMOTO Takeo, KATAOKA Noriyuki, OHASHI Toshiro, SATO Masaaki
In this 3-year study, we have developed a micro tensile tester to measure tensile properties of a single isolated cell and to observe change in intracellular structure during stretching simultaneously. Both ends of the cell were aspirated with glass micropipettes (3-15mm in I.D.) coated with cellular adhesive (Cell-Tak), and one pipette was moved with an electrical manipulator (MMS-77, Shimadzu) to stretch the cell under a microscope (BX50WI, Olympus). The force applied to the cell was measured by the deflection of a cantilever part of the other pipette. To obtain its clear image, the cell was observed with water immersion objectives under the upright microscope. To make cell manipulation easier, the stage of the microscope was fixed and the objectives were moved to adjust the focus. Bovine aortic smooth muscle cells (BASMs) obtained by the explant method (P6-7) and rat aortic smooth muscle cells (RASMs) obtained by the enzymatic dispersion method were successfully stretched with the tester under a physiological salt solution at 37℃ to obtain their tensile properties. Tensile tests of BASMs at various stretch rate show that initial elastic modulus of the cell have a significant positive correlation with the strain rate over 4 %/s. Elastic modulus of BASMs and RASMs were about 3 kPa and about 12kPa, respectively under the strain rate of 0.2-4 %/s. Due to the difference in the cell preparation method, BASMs and RASMs are considered to show synthetic and contractile phenotype, respectively. Contractile cells contain much more contractile proteins than synthetic cells. Contractile proteins may be stiffer than cytoplasm. Contractile cells may thus be stiffer than synthetic cells. The difference in the mechanical properties of BASMs and RASMs in the present study may be due to the difference in the phenotype of the two cell specimens.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), TOHOKU UNIVERSITY, 09558109

アモルファスSiを利用した光導波路一体型カンチレバーの製作
科学研究費助成事業
1998 - 1998
羽根 一博, 大橋 俊朗, 佐々木 実
非伝播性のエバネッセント波から伝播性の光に変換するために、近接場顕微鏡においては尖ったファイバープローブや微細加工プローブが用いられる。よく用いられるファイバープローブに比較して、微細加工プローブの特徴はプローブに多機能を付加できるSiデバイスとの集積化が可能であることである。SiO_xN_y,Si_3N_4やSiO_2などの材料が従来、導波路材料として用いられている。一方、アモルファスシリコン(α-Si)は結晶Siデバイスとの製造互換性をもった興味ある材料であるが、導波路の材料としてはあまり用いられてこなかった。α-Siは0.82μm以上の波長の光に対して吸収が激減し、ほとんど透明になる。一方、結晶Siは1.1μm以上の赤外光において透明である。0.82μm-1.1μmの波長領域に対してα-Siは透明媒質として働き、結晶Siは吸収材料として働く。また、この領域には高出力GaAlAs半導体レーザの波長が含まれている。α-Siが高い屈折率(3.6)を持つことから微小領域に光を閉じこめることが期待でき、クラッドの材料として多くの選択が可能となる。これらのことより、本研究ではα-Siを用いて導波路型カンチレバーを製作した。
半導体レーザを全反射角でプリズムに入射し発生させたエバネッセント波により、プリズム表面に近付けたα-Siカンチレバーを照射し、その様子を光学顕微鏡により観察した。反りのためカンチレバー中を伝播する光がカンチレバーの中央から漏れ出ているのが見られた。広いカンチレバーの方が先端が三角型のカンチレバーよりも明るい光出力が得られた。α-Siカンチレバーからの光の放射を観測することで基本的な導波特性を確認した。次にSiフォトダイオードや半導体レーザなどとの集積化を試みる。
日本学術振興会, 特定領域研究(A), 東北大学, 10135203

細胞内力学伝達機構の解明　　　　　　　　　　　　　　　
1998
Competitive research funding

Vascular Endothelial Cell Response to Mechanical Stimuli
Grants-in-Aid for Scientific Research
1995 - 1997
SATO Masaaki, HELLUMS J David, GIRARD Peggy R, NEREM Robert M, KATAOKA Noriyuki, MATSUMOTO Takeo
As this year was the last term of this project, we examined our results obtained for the past two years form global point of view, and decided to develop some new experimental methods to overcome methodological problems in the previous studies.
1. DEVELOPMENT OF A NEW TECHNIQUE TO OBSERVE ACTIN FILAMENTS IN ALIVE CELLS
Immunofluorescence technique which has been utilized widely to observe intracellular actin filaments requires fixation of the cells, and it was vey difficult to observe actin filament dynamics in intact cells. To overcome this problem, we have introduced a combined gene of alpha-actinin, a bridging element of actin filaments and GFP (Green Fluorescent Protein) into vascular endothelial cells. Cells introduced such genes have autofluorescence in their alpha-actinin, and thus their actin filaments. We successfully observed actin filament dynamics in cells under static and shear-exposed conditions.
2. DEVELOPMENT OF A FLOW-LOADING SYSTEM FOR ENDOTHELIAL CELLS ON ARTERIAL INTRALUMINAL SURFACE
There have been a lot of contradictions between results obtained from animal experiments and that based on cultured endothelial cells. To establish a new method compensating shortcomings of both experiments, we have developed a new flow-loading system to impose shear stress on the endothelial surface of an arterial segment, in which a piece of a cut-opened arterial segment is laid flat to expose its intraluminal surface to flow in a parallel plate chamber. We applied 1 Pa of shear stress to rabbit thoracic aortas perpendicularly to their vessel axis, and found that most of the endothelial cells changed their alignment parallel to the direction of flow in 72 hours. We concluded that this system can be widely used for the future studies on the mechanical response of vascular endothelial cells to shear stress.
Japan Society for the Promotion of Science, Grant-in-Aid for international Scientific Research, Tohoku University, 07044112

微細加工デバイスを用いた細胞機能の計測　　　　　　　　　　　　　　　
1997
Competitive research funding

ピペット吸引による血管壁の非線形局所力学特性の測定に関する研究
科学研究費補助金(奨励研究(A))
1996 - 1996
大橋 俊朗
1.はじめに 血管壁の大変形時の弾性特性を知るための新たな測定法として、二軸引張装置により予めひずみを与えた状態でピペット吸引を行うことで試料の大変形時の弾性係数を推定する方法を提案した。また、内圧負荷試験を併せて行い両試験法による結果を比較・検討した。2.方法 ブタ胸部下行大動脈(外径約20mm、壁厚約2mm)から40x40mm程度の十字型試料を、主軸を血管壁の軸および円周方向に一致させながら十字型金型で打ち抜いた。試料を内腔面を上にして自作の二軸引張装置に固定し、周囲を室温の生理食塩水で満たした。ネジ送りステージを調節して軸および円周方向の伸び比を1.0〜1.5程度の範囲で0.1ずつ変化させながら、内径800μmのガラスピペットで試料表面を吸引した。ピペット内の試料の変形量はビデオマイクロスコープを通してモニタ上で二値化して求めた。一方、軸および円周方向の試料のひずみはCCDカメラで撮影し、試料表面の標線を二値化して求めた。弾性率Eは実験から得られた吸引圧-変形量関係を有限要素法解析から得られた同様の関係と比較することで求めた。また、別途比較のため同一個体の円筒状試料に対して従来法の内圧負荷試験を行い増分弾性係数H_<θθ>を求めた。3.結果および考察 軸方向伸長比λ_zが一定の場合、Eは円周方向伸長比λ_θが増加するに伴い単調に増加した。一方H_<θθ>は指数関数的に増...
文部科学省, 奨励研究(A), 東北大学, Principal investigator, Competitive research funding, 08780813