Researcher basic information

• 博士（獣医学）, 北海道大学

• https://researchmap.jp/vet-ned?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201501027810194155

• 201501027810194155

• Life Science, Veterinary medical science
• Life Science, Biomedical engineering

• Bachelor's degree program, School of Veterinary Medicine
• Doctoral (PhD) degree program, Graduate School of Veterinary Medicine

Research activity information

• Jun. 2025, LE STUDIUM Loire Valley Institute of Advanced Studies, LE STUDIUM Visiting Researcher Award
• Jun. 2021, 日本獣医学会, JVMS Award 2020
  An area ratio of thyroid gland to common carotid artery for evaluating the thyroid gland size
  佐々木東、永田矩之、森下啓太郎、大菅辰幸、笹岡一慶、横山望、大田寛、滝口満喜
• Nov. 2011, 第10回日本超音波治療研究会 若手研究者の部 優秀賞
  佐々木東
• Sep. 2011, 日本超音波医学会第41回北海道地方会 優秀演題賞
  佐々木東

• Effects of cardiac volume loading on left atrial stiffness estimated by 2-dimensional echocardiography in healthy dogs.
  Tatsuyuki Osuga; Masahiro Tamura; Noboru Sasaki; Mitsuyoshi Takiguchi
  American journal of veterinary research, 1, 7, 14 Aug. 2025, [International Magazine]
  English, Scientific journal, OBJECTIVE: To elucidate the effect of cardiac volume loading, which should physiologically increase left atrial (LA) stiffness (LASt), on echocardiographically estimated LASt in healthy dogs. METHODS: 6 healthy Beagle dogs were anesthetized. In each dog, a Swan-Ganz catheter was placed to measure the mean pulmonary capillary wedge pressure. Cardiac volume loading was performed by IV infusion with hydroxyethylated starch solution. Echocardiography was transthoracically conducted at the baseline and at mean pulmonary capillary wedge pressures of 10 to 15, 15 to 20, 20 to 25, and 25 to 30 mm Hg. The echocardiographic indicators of LA pressure, including the peak velocity of early diastolic transmitral flow (E), ratio of E to the isovolumic relaxation time (E/IVRT), ratio of E to the peak velocity of early diastolic mitral annular motion (E/E'), and LA reservoir strain, were determined to estimate LASt. RESULTS: During cardiac volume loading, E, E/IVRT, and LA reservoir strain were increased, and E/E' was decreased, when compared with the baseline. Consequently, LASts estimated by using E, E/IVRT, and E/E' were decreased or remained unchanged during cardiac volume loading. CONCLUSIONS: Echocardiographically estimated LASt may not be increased by cardiac volume loading in healthy dogs. CLINICAL RELEVANCE: Healthy dogs may not be an appropriate model to elucidate the effect of cardiac volume loading on echocardiographically estimated LASt. This is problematic, especially for dogs with myxomatous mitral valve disease that are older and may have cardiac dysfunction.
• Evaluation of the course of improvement with molnupiravir treatment for feline infectious peritonitis.
  Shino Yoshida; Mei Sugawara-Suda; Kazuyoshi Sasaoka; Noboru Sasaki; Nozomu Yokoyama; Kensuke Nakamura; Keitaro Morishita; Sangho Kim; Takafumi Sunaga; Mitsuyoshi Takiguchi
  The Canadian veterinary journal = La revue veterinaire canadienne, 66, 5, 546, 554, May 2025, [International Magazine]
  English, Scientific journal, OBJECTIVE: To clarify the clinical course during molnupiravir treatment for feline infectious peritonitis (FIP). ANIMALS AND PROCEDURE: Cats diagnosed with FIP and treated with molnupiravir at Hokkaido University Veterinary Teaching Hospital (Sapporo, Hokkaido, Japan) were retrospectively reviewed. RESULTS: Eleven cats were eligible for inclusion. Six cats had effusive FIP and 5 had non-effusive FIP. In noneffusive cases, 2 cats had neurological abnormalities at diagnosis, whereas 1 additional cat developed neurological signs during treatment. The median initial dosage of molnupiravir was 13.0 mg/kg (range: 10.0 to 15.0 mg/kg), PO, q12h. One cat died after 11 d and the remaining 10 cats completed an 84-day course of treatment. All neurological cases were given dosage increases, extended treatment duration, or both. The median final dosage of molnupiravir in non-neuro-FIP cases was 13.1 mg/kg (range: 10.0 to 15.0 mg/kg), PO, q12h, whereas dosages in neuro-FIP cases were 15.0, 15.2, and 17.2 mg/kg, PO, q12h in the 3 affected cats, respectively. In non-neurological cases, dysrexia, lethargy, and high serum amyloid A were resolved within 15 d. Total follow-up duration ranged from 175 to 362 d. No relapses were observed. CONCLUSION AND CLINICAL RELEVANCE: Monitoring responses to molnupiravir treatment requires observing clinical signs and conducting clinicopathological evaluations, including acute-phase protein evaluation.
• Reference intervals for urinary metanephrines to creatinine ratios in dogs in Japan.
  Noriyuki Nagata; Yoshinori Ikenaka; Hiryu Sawamura; Noboru Sasaki; Mitsuyoshi Takiguchi
  The Journal of veterinary medical science, 03 Sep. 2024, [Domestic magazines]
  English, Scientific journal, The urinary normetanephrine to creatinine ratio (uNMN/Cr) and urinary metanephrine to creatinine ratio (uMN/Cr) are commonly evaluated for the diagnosis of pheochromocytomas (PCC) in dogs. This study aimed to establish reference intervals for uNMN/Cr and uMN/Cr in 56 healthy dogs in Japan and to investigate the effect of urine collection methods on these measurements in 15 non-PCC dogs. The upper limits of reference intervals for uNMN/Cr and uMN/Cr were 124.4 nmol/mmol (90% confidence interval [CI] 107.7-137.0) and 121.1 nmol/mmol (90% CI 102.8-145.1), respectively. Both uNMN/Cr and uMN/Cr were significantly higher when urine was collected in the hospital compared to at home. Several factors, including the method of urine collection, should be considered when utilizing these reference intervals.
• Urinary steroid profiling using liquid chromatography-tandem mass spectrometry for the diagnosis of canine Cushing's syndrome.
  N Nagata; H Sawamura; Y Ikenaka; K Morishita; K Hosoya; N Sasaki; K Nakamura; M Takiguchi
  Veterinary journal (London, England : 1997), 106151, 106151, 29 May 2024, [International Magazine]
  English, Scientific journal, Serum cortisol measurements by chemiluminescence enzyme immunoassay (CLEIA) are widely used to diagnose hypercortisolism (HC) or Cushing's syndrome in dogs. However, they are associated with problems such as the need for multiple blood collections under stressful conditions or cross-reactivity between hormones. Therefore, a less invasive and more accurate diagnostic method is required. This study aimed to develop a urinary steroid profile analysis method using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and to evaluate its clinical usefulness. Sixty-five healthy dogs and 38 dogs with suspected HC were included in the study. Using LC/MS/MS, the levels of 11 steroid hormones in the urine were determined. We established the upper limit of the reference interval for each urinary steroid-to-creatinine ratio and evaluated their diagnostic performances. The levels of the five steroid hormones were significantly higher in the 14 dogs with HC than in the 24 dogs with mimicking HC and 65 healthy dogs. The urinary corticosterone-to-creatinine ratio showed the highest diagnostic accuracy (area under the curve, 0.96). A significant correlation was seen between urinary cortisol concentrations measured by LC/MS/MS and CLEIA (rs = 0.88, P <0.001), although the CLEIA measurements were significantly higher than the LC/MS/MS measurements (P <0.001). LC/MS/MS-based urinary steroid profiles are a promising tool for diagnosing canine HC.
• Delivery of Anticancer Drugs Using Microbubble-Assisted Ultrasound in a 3D Spheroid Model.
  Marie Roy; Corentin Alix; Julien Burlaud-Gaillard; Damien Fouan; William Raoul; Ayache Bouakaz; Emmanuelle Blanchard; Thierry Lecomte; Marie-Claude Viaud-Massuard; Noboru Sasaki; Sophie Serrière; Jean-Michel Escoffre
  Molecular pharmaceutics, 21, 2, 831, 844, 05 Feb. 2024, [International Magazine]
  English, Scientific journal, Tumor spheroids are promising three-dimensional (3D) in vitro tumor models for the evaluation of drug delivery methods. The design of noninvasive and targeted drug methods is required to improve the intratumoral bioavailability of chemotherapeutic drugs and reduce their adverse off-target effects. Among such methods, microbubble-assisted ultrasound (MB-assisted US) is an innovative modality for noninvasive targeted drug delivery. The aim of the present study is to evaluate the efficacy of this US modality for the delivery of bleomycin, doxorubicin, and irinotecan in colorectal cancer (CRC) spheroids. MB-assisted US permeabilized the CRC spheroids to propidium iodide, which was used as a drug model without affecting their growth and viability. Histological analysis and electron microscopy revealed that MB-assisted US affected only the peripheral layer of the CRC spheroids. The acoustically mediated bleomycin delivery induced a significant decrease in CRC spheroid growth in comparison to spheroids treated with bleomycin alone. However, this US modality did not improve the therapeutic efficacy of doxorubicin and irinotecan on CRC spheroids. In conclusion, this study demonstrates that tumor spheroids are a relevant approach to evaluate the efficacy of MB-assisted US for the delivery of chemotherapeutics.
• Transcranial Doppler ultrasonography detects the elevation of cerebral blood flow during ictal-phase of pentetrazol-induced seizures in dogs.
  Kazuyoshi Sasaoka; Hiroshi Ohta; Tomohito Ishizuka; Kazuki Kojima; Noboru Sasaki; Mitsuyoshi Takiguchi
  American journal of veterinary research, 83, 4, 331, 338, 28 Jan. 2022, [International Magazine]
  English, Scientific journal, OBJECTIVE: To investigate the association between changes in cerebral blood flow and electrographic epileptic seizure in dogs using transcranial Doppler ultrasonography (TCD). ANIMALS: 6 healthy Beagle dogs. PROCEDURES: Each dog was administered pentetrazol (1.5 mg/kg/min) or saline (0.9% NaCl) solution under general anesthesia with continuous infusion of propofol. Both pentetrazol and saline solution were administered to all 6 dogs, with at least 28 days interval between the experiments. Blood flow waveforms in the middle cerebral artery and the basilar artery were obtained using TCD at baseline, after pentetrazol administration, and after diazepam administration. TCD velocities, including peak systolic velocity, end-diastolic velocity, and mean velocity and resistance variables, were determined from the Doppler waveforms. RESULTS: During ictal-phase of pentetrazol-induced seizures, the TCD velocities significantly increased in the basilar and middle cerebral arteries while TCD vascular resistance variables did not change in either artery. The TCD velocities significantly decreased after diazepam administration. Systemic parameters, such as the heart rate, mean arterial pressure, systemic vascular resistance, cardiac index, end-tidal carbon dioxide, oxygen saturation, and body temperature, did not change significantly during seizures. CLINICAL RELEVANCE: This study showed that cerebral blood flow, as obtained from TCD velocities, increased by 130% during ictal-phase of pentetrazol-induced seizures in dogs. The elevated velocities returned to baseline after seizure suppression. Thus, TCD may be used to detect electrographic seizures during the treatment of status epilepticus in dogs, and further clinical studies clarifying the association between changes in cerebral blood flow and non-convulsive seizure cases are needed.
• Local cerebral blood flow assessment using transcranial Doppler ultrasonography in a dog with brain infarction in the right middle cerebral artery territory
  Kazuyoshi SASAOKA; Hiroshi OHTA; Tomohito ISHIZUKA; Tatsuyuki OSUGA; Keitaro MORISHITA; Noboru SASAKI; Mitsuyoshi TAKIGUCHI
  Journal of Veterinary Medical Science, 84, 10, 1385, 1390, Japanese Society of Veterinary Science, 2022
  Scientific journal
• Safety Assessment of Ultrasound-Assisted Intravesical Chemotherapy in Normal Dogs: A Pilot Study.
  Noboru Sasaki; Yoshinori Ikenaka; Keisuke Aoshima; Teiichiro Aoyagi; Nobuki Kudo; Kensuke Nakamura; Mitsuyoshi Takiguchi
  Frontiers in pharmacology, 13, 837754, 837754, 2022, [International Magazine]
  English, Scientific journal, Intravesical chemotherapy after transurethral resection is a treatment option in patients with non-muscle invasive bladder cancer. The efficacy of intravesical chemotherapy is determined by the cellular uptake of intravesical drugs. Therefore, drug delivery technologies in the urinary bladder are promising tools for enhancing the efficacy of intravesical chemotherapy. Ultrasound-triggered microbubble cavitation may enhance the permeability of the urothelium, and thus may have potential as a drug delivery technology in the urinary bladder. Meanwhile, the enhanced permeability may increase systemic absorption of intravesical drugs, which may increase the adverse effects of the drug. The aim of this preliminary safety study was to assess the systemic absorption of an intravesical drug that was delivered by ultrasound-triggered microbubble cavitation in the urinary bladder of normal dogs. Pirarubicin, a derivative of doxorubicin, and an ultrasound contrast agent (Sonazoid) microbubbles were administered in the urinary bladder. Ultrasound (transmitting frequency 5 MHz; pulse duration 0.44 μsec; pulse repetition frequency 7.7 kHz; peak negative pressure -1.2 MPa) was exposed to the bladder using a diagnostic ultrasound probe (PLT-704SBT). The combination of ultrasound and microbubbles did not increase the plasma concentration of intravesical pirarubicin. In addition, hematoxylin and eosin staining showed that the combination of ultrasound and microbubble did not cause observable damages to the urothelium. Tissue pirarubicin concentration in the sonicated region was higher than that of the non-sonicated region in two of three dogs. The results of this pilot study demonstrate the safety of the combination of intravesical pirarubicin and ultrasound-triggered microbubble cavitation, that is, ultrasound-assisted intravesical chemotherapy.
• Serum steroid profiling of hepatocellular carcinoma associated with hyperadrenocorticism in dogs: A preliminary study.
  Thandar Oo; Noboru Sasaki; Yoshinori Ikenaka; Takahiro Ichise; Noriyuki Nagata; Nozomu Yokoyama; Kazuyoshi Sasaoka; Keitaro Morishita; Kensuke Nakamura; Mitsuyoshi Takiguchi
  Frontiers in veterinary science, 9, 1014792, 1014792, 2022, [International Magazine]
  English, Scientific journal, Background: Hepatocellular carcinoma (HCC) is one of the most common primary liver tumors in humans and dogs. Excessive adrenocortical hormone exposure may cause steroid hepatopathy, which may develop into HCC. In our previous study, hyperadrenocorticism (HAC) was a highly concurrent disease in dogs with HCC. Therefore, this study hypothesized that adrenal steroid alterations might be involved in hepatocarcinogenesis and aimed to specify the relationship between HAC and HCC in dogs. Materials and methods: This study included 46 dogs brought to the Hokkaido University Veterinary Teaching Hospital between March 2019 and December 2020. Owners gave their signed consent for blood collection on their first visit. A total of 19 steroids (14 steroids and 5 metabolites) in the baseline serum of 15 dogs with HCC, 15 dogs with HAC, and 10 dogs with both diseases were quantitatively measured using the developed liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) method. Results: In each group, 11 steroids were detected higher than 50%. The detection rate of steroid hormones did not significantly differ between the groups (p > 0.05). Principle component analysis (PCA) showed that the steroid profiles of the three groups were comparable. Median steroid hormone concentrations were not significantly different between the study diseases (p > 0.05). Conclusion: The developed LC/MS/MS was useful for measuring steroid hormones. Although it was clear that HAC was concurrent in dogs with HCC, none of the serum steroids was suggested to be involved in HCC.
• Simultaneous steroids measurement in dogs with hyperadrenocorticism using a column-switching liquid chromatography-tandem mass spectrometry method.
  Noboru Sasaki; Thandar Oo; Yoshikazu Yasuda; Takahiro Ichise; Noriyuki Nagata; Nozomu Yokoyama; Kazuyoshi Sasaoka; Keitaro Morishita; Shouta Mm Nakayama; Mayumi Ishizuka; Kensuke Nakamura; Mitsuyoshi Takiguchi; Yoshinori Ikenaka
  The Journal of veterinary medical science, 83, 11, 1634, 1642, 31 Oct. 2021, [Domestic magazines]
  English, Scientific journal, We developed an analytical method using an on-line column-switching liquid chromatography with triple quadrupole mass spectrometry (LC/MS/MS) for quantifying multiple steroids in serum. Using the developed method, we evaluated the serum concentration of nine steroids (cortisol, corticosterone, cortisone, 11-deoxycortisol, 21-deoxycortisol, deoxycorticosterone, progesterone, 17α-OH-progesterone and aldosterone) in dogs with hyperadrenocorticism (HAC). Serum was mixed with stable isotope internal standards and thereafter purified by the automated column-switching system. The limit of detection ranged 2-16 pg/ml for nine steroids. In the baseline samples, five steroids (cortisol, corticosterone, cortisone, 11-deoxycortisol, and 17α-OH-progesterone) were detected in all dogs. The concentrations of cortisone, 11-deoxycortisol, and 17α-OH-progesterone in dogs with HAC (n=19) were significantly higher those in dogs without HAC (n=15, P<0.02). After the adrenocorticotropic hormone stimulation test, six steroids (cortisol, corticosterone, cortisone, 11-deoxycortisol, 17α-OH-progesterone, and deoxycorticosterone) were above the limit of quantification in all dogs. Cortisol, corticosterone, cortisone, and deoxycorticosterone concentrations of dogs with HAC were significantly higher than those of dogs without HAC (P<0.02). In addition, 11-deoxycortisol and 17α-OH-progesterone concentration was higher in dogs with HAC than in dogs without HAC (P=0.044 and P=0.048, respectively). The on-line column-switching LC/MS/MS would be feasible for measuring multiple steroids in dog serum. The results suggest that cortisone, 11-deoxycortisol, and 17α-OH-progesterone would be related to HAC. Further studies are warranted to assess the clinical feasibility of steroid profile in dogs with HAC.
• Urinary free metanephrines measurement in dogs with adrenal gland diseases using a new simple liquid chromatography tandem mass spectrometry method.
  Noboru Sasaki; Yoshinori Ikenaka; Yumiko Inoue; Takahiro Ichise; Noriyuki Nagata; Mayumi Ishizuka; Syouta Mm Nakayama; Kensuke Nakamura; Mitsuyoshi Takiguchi
  The Journal of veterinary medical science, 83, 4, 648, 655, 09 Apr. 2021, [Domestic magazines]
  English, Scientific journal, Measurement of urinary metanephrines in spot samples is used for the diagnosis of canine pheochromocytoma (PC). We describe a simple analytical method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for measuring free metanephrine (MN) and normetanephrine (NMN) in spot urine samples. Using the developed method, we evaluated the stability of urinary free-MN and free-NMN at various storing conditions. In addition, we assessed the feasibility of urinary free-MN and -NMN measurement for diagnosing PC. Urine samples were mixed with stable isotope internal standards and thereafter purified by ultrafiltration. The purified samples were analyzed by LC-MS/MS in the multiple reaction monitoring mode after separation on a multimode octa decyl silyl column. The coefficient of variation of free-MN and -NMN measurement was 7.6% and 5.5%, respectively. The linearity range was 0.5-10 µg/l for both analytes. Degradation was less than 10% for both analytes under any of the storage conditions. The median free-NMN ratio to creatinine of 9 PC dogs (595, range 144-47,961) was significantly higher (P<0.05) than that of 13 dogs with hypercortisolism (125, range 52-224) or 15 healthy dogs (85, range 50-117). The developed method is simple and may not require acidification of spot urine. The results of this preliminary retrospective study suggest that the measurement of urinary free metanephrines is a promising tool for diagnosing canine PC.
• An area ratio of thyroid gland to common carotid artery for evaluating the thyroid gland size.
  Noboru Sasaki; Noriyuki Nagata; Keitaro Morishita; Tatsuyuki Osuga; Kazuyoshi Sasaoka; Nozomu Yokoyama; Hiroshi Ohta; Mitsuyoshi Takiguchi
  The Journal of veterinary medical science, 82, 7, 1012, 1016, 31 Jul. 2020, [Domestic magazines]
  English, Scientific journal, The feasibility of ultrasonographic measurement of thyroid gland area to common carotid artery (TG:CCA) was investigated. Twenty-one healthy, 12 hypothyroid and 18 non-thyroid illness (NTI) dogs were evaluated. The area of thyroid lobe and common carotid artery in right and left sides were measured using the same ultrasonographic images in transverse plane. The average of the right and left ratio was calculated as TG:CCA. The median TG:CCA of 21 healthy dogs was 1.53, and it did not correlate either body weight or age. The median TG:CCA of 12 hypothyroid dogs was 0.81, which was significantly lower than that of 18 NTI dogs (1.81, P<0.001). If the cut off value <1.12 was used, TG:CCA indicated hypothyroidism with a sensitivity of 100%, specificity of 83%, and accuracy of 90%. Our data indicated that TG:CCA was independent of both body weight, which may contribute to consistent measurement of thyroid size. The results of this study suggest that TG:CCA is a promising tool for diagnosing canine hypothyroidism.
• Endothelial Cells, First Target of Drug Delivery Using Microbubble-Assisted Ultrasound.
  Antoine Presset; Corentin Bonneau; Sasaoka Kazuyoshi; Lydie Nadal-Desbarats; Takigucho Mitsuyoshi; Ayache Bouakaz; Nobuki Kudo; Jean-Michel Escoffre; Noboru Sasaki
  Ultrasound in medicine & biology, 46, 7, 1565, 1583, Jul. 2020, [International Magazine]
  English, Scientific journal, Microbubble-assisted ultrasound has emerged as a promising method for local drug delivery. Microbubbles are intravenously injected and locally activated by ultrasound, thus increasing the permeability of vascular endothelium for facilitating extravasation and drug uptake into the treated tissue. Thereby, endothelial cells are the first target of the effects of ultrasound-driven microbubbles. In this review, the in vitro and in vivo bioeffects of this method on endothelial cells are described and discussed, including aspects on the permeabilization of biologic barriers (endothelial cell plasma membranes and endothelial barriers), the restoration of their integrity, the molecular and cellular mechanisms involved in both these processes, and the resulting intracellular and intercellular consequences. Finally, the influence of the acoustic settings, microbubble parameters, treatment schedules and flow parameters on these bioeffects are also reviewed.
• Editorial: Bubbles, Droplets and Micelles for Acoustically-Mediated Drug/Gene Delivery.
  Jean-Michel Escoffre; Baudouin Denis de Senneville; Noboru Sasaki; Marc Derieppe
  Frontiers in pharmacology, 11, 954, 954, 2020, [International Magazine]
  English
• Usefulness of noninvasive shear wave elastography for the assessment of hepatic fibrosis in dogs with hepatic disease.
  Tamura M; Ohta H; Shimbo G; Osuga T; Sasaki N; Morishita K; Kagawa Y; Takiguchi M
  Journal of veterinary internal medicine, 33, 5, 2067, 2074, Sep. 2019, [Peer-reviewed]
• Evaluation of liver and spleen stiffness of healthy dogs by use of two-dimensional shear wave elastography.
  Tamura M; Ohta H; Nisa K; Osuga T; Sasaki N; Morishita K; Takiguchi M
  American journal of veterinary research, 80, 4, 378, 384, Apr. 2019, [Peer-reviewed]
• Spatial and temporal profile of cisplatin delivery by ultrasound-assisted intravesical chemotherapy in a bladder cancer model.
  Noboru Sasaki; Kazuhiro Ishi; Nobuki Kudo; Shouta M M Nakayama; Kensuke Nakamura; Keitaro Morishita; Hiroshi Ohta; Mayumi Ishizuka; Mitsuyoshi Takiguchi
  PloS one, 12, 11, e0188093, 2017, [International Magazine]
  English, Scientific journal, Non-muscle invasive bladder cancer is one of the most common tumors of the urinary tract. Despite the current multimodal therapy, recurrence and progression of disease have been challenging problems. We hereby introduced a new approach, ultrasound-assisted intravesical chemotherapy, intravesical instillation of chemotherapeutic agents and microbubbles followed by ultrasound exposure. We investigated the feasibility of the treatment for non-muscle invasive bladder cancer. In order to evaluate intracellular delivery and cytotoxic effect as a function to the thickness, we performed all experiments using a bladder cancer mimicking 3D culture model. Ultrasound-triggered microbubble cavitation increased both the intracellular platinum concentration and the cytotoxic effect of cisplatin at the thickness of 70 and 122 μm of the culture model. The duration of enhanced cytotoxic effect of cisplatin by ultrasound-triggered microbubble cavitation was approximately 1 hr. Based on the distance and duration of delivery, we further tested the feasibility of repetition of the treatment. Triple treatment increased the effective distance by 1.6-fold. Our results clearly showed spatial and temporal profile of delivery by ultrasound-triggered microbubble cavitation in a tumor-mimicking structure. Furthermore, we demonstrated that the increase in intracellular concentration results in the enhancement of the cytotoxic effect in a structure with the certain thickness. Repetition of ultrasound exposure would be treatment of choice in future clinical application. Our results suggest ultrasound-triggered microbubble cavitation can be repeatable and is promising for the local control of non-muscle invasive bladder cancer.
• Development of a tumor tissue-mimicking model with endothelial cell layer and collagen gel for evaluating drug penetration.
  Noboru Sasaki; Clemens Bos; Jean-Michel Escoffre; Gert Storm; Chrit Moonen
  International journal of pharmaceutics, 482, 1-2, 118, 22, 30 Mar. 2015, [International Magazine]
  English, Scientific journal, The endothelial cells of vessels, the interstitial matrix and the distance between the tumor cells and vessels, are the major penetration barriers for intravenously administered anticancer drugs in reaching tumor cells after intravenous injection. The availability of a tumor tissue-mimicking model that includes both the endothelial cell layer and the extracellular matrix would be beneficial to assess drug penetration in early stages of drug development. Here, we propose a novel in vitro model for studying the above mentioned barriers. Human umbilical vein endothelial cells were cultured as a single layer on a collagen type-I coated permeable cell culture insert. After culturing for five days, the insert was superimposed on collagen type-I gel containing cancer cells. The system was evaluated for assessing penetration-enhancement by ultrasound triggered microbubble cavitation. Our model allowed visualization of the penetration distance of a model drug (fluorescein isothiocyanate - Dextran 500000-conjugated, FD500) from the endothelial cell layer into the cancer cell containing collagen matrix upon different sonication treatments. Initial results showed that the model allows the visualization of drug penetration and that the endothelial cell layer is affecting this. The presented in vitro model aims to mimic vessels and stromal tissue in cancer, and thus can aid in the assessment of drug penetration in the case of tumor-targeted drug delivery, and in the reduction and refinement of animal studies.
• Mild hyperthermia influence on Herceptin(®) properties.
  Jean-Michel Escoffre; Roel Deckers; Noboru Sasaki; Clemens Bos; Chrit Moonen
  Radiology and oncology, 49, 1, 41, 9, Mar. 2015, [International Magazine]
  English, Scientific journal, BACKGROUND: Mild hyperthermia (mHT) increases the tumor perfusion and vascular permeability, and reduces the interstitial fluid pressure, resulting in better intra-tumoral bioavailability of low molecular weight drugs. This approach is potentially also attractive for delivery of therapeutic macromolecules, such as antibodies. Here, we investigated the effects of mHT on the stability, immunological and pharmacological properties of Herceptin(®), a clinically approved antibody, targeting the human epidermal growth factor receptor 2 (HER-2) overexpressed in breast cancer. RESULTS: Herceptin(®) was heated to 37°C (control) and 42°C (mHT) for 1 hour. Formation of Herceptin(®) aggregates was measured using Nile Red assay. mHT did not result in additional Herceptin(®) aggregates compared to 37°C, showing the Herceptin(®) stability is unchanged. Immunological and pharmacological properties of Herceptin(®) were evaluated following mHT using HER-2 positive breast cancer cells (BT-474). Exposure of Herceptin(®) to mHT preserved recognition and binding affinity of Herceptin(®) to HER-2. Western-blot and cell proliferation assays on BT-474 cells showed that mHT left the inhibitory activities of Herceptin(®) unchanged. CONCLUSIONS: The stability, and the immunological and pharmacological properties of Herceptin(®) are not negatively affected by mHT. Further in-vivo studies are required to evaluate the influence of mHT on intra-tumoral bioavailability and therapeutic effectiveness of Herceptin(®).
• Ultrasound image-guided therapy enhances antitumor effect of cisplatin.
  Noboru Sasaki; Nobuki Kudo; Kensuke Nakamura; Sue Yee Lim; Masahiro Murakami; W R Bandula Kumara; Yu Tamura; Hiroshi Ohta; Masahiro Yamasaki; Mitsuyoshi Takiguchi
  Journal of medical ultrasonics (2001), 41, 1, 11, 21, Jan. 2014, [Domestic magazines]
  English, Scientific journal, PURPOSE: The aim of this study was to clarify whether ultrasound image-guided cisplatin delivery with an intratumor microbubble injection enhances the antitumor effect in a xenograft mouse model. METHODS: Canine thyroid adenocarcinoma cells were used for all experiments. Before in vivo experiments, the cisplatin and microbubble concentration and ultrasound exposure time were optimized in vitro. For in vivo experiments, cells were implanted into the back of nude mice. Observed by a diagnostic ultrasound machine, a mixture of cisplatin and ultrasound contrast agent, Sonazoid, microbubbles was injected directly into tumors. The amount of injected cisplatin and microbubbles was 1 μg/tumor and 1.2 × 10(7) microbubbles/tumor, respectively, with a total injected volume of 20 μl. Using the same diagnostic machine, tumors were exposed to ultrasound for 15 s. The treatment was repeated four times. RESULTS: The combination of cisplatin, microbubbles, and ultrasound significantly delayed tumor growth as compared with no treatment (after 18 days, 157 ± 55 vs. 398 ± 49 mm(3), P = 0.049). Neither cisplatin alone nor the combination of cisplatin and ultrasound delayed tumor growth. The treatment did not decrease the body weight of mice. CONCLUSION: Ultrasound image-guided anticancer drug delivery may enhance the antitumor effects of drugs without obvious side effects.
• Activation of microbubbles by short-pulsed ultrasound enhances the cytotoxic effect of cis-diamminedichloroplatinum (II) in a canine thyroid adenocarcinoma cell line in vitro.
  Noboru Sasaki; Nobuki Kudo; Kensuke Nakamura; Sue Yee Lim; Masahiro Murakami; W R Bandula Kumara; Yu Tamura; Hiroshi Ohta; Masahiro Yamasaki; Mitsuyoshi Takiguchi
  Ultrasound in medicine & biology, 38, 1, 109, 18, Jan. 2012, [International Magazine]
  English, Scientific journal, Ultrasound targeted microbubble destruction has succeeded in delivering drugs and genes. This study was designed to explore characteristics of ultrasound targeted microbubble destruction using short-pulsed diagnostic ultrasound. Canine thyroid adenocarcinoma cells were exposed to short-pulsed diagnostic ultrasound in the presence of cis-diamminedichloroplatinum (II) (cisplatin) and ultrasound contrast agent Sonazoid(®) microbubbles. The cytotoxic effect of cisplatin was enhanced by short-pulsed diagnostic ultrasound and microbubbles. Incubation time with microbubbles influenced the cytotoxic effect of cisplatin. However, exposure duration did not affect the cytotoxic effect of cisplatin. Therefore, short-pulsed diagnostic ultrasound may activate microbubbles near cells and deliver cisplatin into cells. In addition, activation of microbubbles may be concluded in a short time. Our results suggest that short exposure duration could be potentially sufficient to induce efficient drug delivery by ultrasound targeted microbubble destruction using short-pulsed diagnostic ultrasound.
• Contrast-enhanced ultrasonography for characterization of focal splenic lesions in dogs.
  Nakamura K; Sasaki N; Murakami M; Bandula Kumara WR; Ohta H; Yamasaki M; Takagi S; Osaki T; Takiguchi M
  Journal of veterinary internal medicine / American College of Veterinary Internal Medicine, 24, 6, 1290, 1297, 6, Nov. 2010, [Peer-reviewed]
  Nakamura K, Sasaki N, Murakami M, Bandula Kumara WR, Ohta H, Yamasaki M, Takagi S, Osaki T, Takiguchi M, <i>Journal of veterinary internal medicine / American College of Veterinary Internal Medicine</i>, 2010, vol. 24, no. 6, pp. 1290-1297

• 低強度パルス超音波による培養神経細胞刺激作用の検討
  佐々木 東; 工藤 信樹; 滝口 満喜, 超音波医学, 51, Suppl., S672, S672, Apr. 2024
  (公社)日本超音波医学会, Japanese
• 殺細胞効果を有する液体の膀胱内注入治療法の検討
  佐々木東; 池中良徳; 安井博宣; 中村健介; 滝口満喜, 日本獣医学会学術集会講演要旨集, 167th, 2024
• 心疾患の犬におけるShear wave elastography/Dispersion Imagingの有用性の検討
  塩原希; 中村健介; 横山望; 佐々木東; 滝口満喜, 日本獣医循環器学会抄録(CD-ROM), 119th, 2023
• 犬尿中コルチゾール/クレアチニン比の基準値の確立とクッシング症候群の診断への応用
  永田 矩之; 澤村 飛龍; 五日市 大介; 森下 啓太郎; 細谷 謙次; 横山 望; 笹岡 一慶; 佐々木 東; 中村 健介; 池中 良徳; 滝口 満喜, 北海道獣医師会雑誌, 66, 8, 286, 286, Aug. 2022
  (公社)北海道獣医師会, Japanese
• 毛細血管ゲルファントムを用いた微小気泡ダイナミクスの高速度観察による弾性率の推定
  Hu Xinyue; 小俣 大樹; 鈴木 亮; 佐々木 東; 工藤 信樹, 超音波医学, 49, Suppl., S802, S802, Apr. 2022
  (公社)日本超音波医学会, Japanese
• 抗がん剤付着型アルブミンナノ粒子と微小気泡を用いた超音波薬物送達の機序検討
  新里 美瑠; 胡 新げつ; 小俣 大樹; 鈴木 亮; 佐々木 東; 工藤 信樹, 超音波医学, 49, Suppl., S803, S803, Apr. 2022
  (公社)日本超音波医学会, Japanese
• 毛細血管ゲルファントムを用いた微小気泡ダイナミクスの高速度観察による弾性率の推定
  Hu Xinyue; 小俣 大樹; 鈴木 亮; 佐々木 東; 工藤 信樹, 超音波医学, 49, Suppl., S802, S802, Apr. 2022
  (公社)日本超音波医学会, Japanese
• 抗がん剤付着型アルブミンナノ粒子と微小気泡を用いた超音波薬物送達の機序検討
  新里 美瑠; 胡 新げつ; 小俣 大樹; 鈴木 亮; 佐々木 東; 工藤 信樹, 超音波医学, 49, Suppl., S803, S803, Apr. 2022
  (公社)日本超音波医学会, Japanese
• LC-MS/MSを用いたステロイドホルモンの一斉分析法による、副腎皮質機能亢進症(クッシング症候群)の病態解明について
  一瀬 貴大; 安田 淑一; 佐々木 東; 滝口 満喜; 中山 翔太; 石塚 真由美; 池中 良徳, JSBMS Letters, 46, Suppl., 75, 75, Aug. 2021
  (一社)日本医用マススペクトル学会, Japanese
• 超音波で生体の壁を超える 超音波と気泡を併用する膀胱内注入療法の犬における安全性検討
  佐々木 東; 青柳 貞一郎; 池中 良徳; 工藤 信樹; 中村 健介; 滝口 満喜, 超音波医学, 48, Suppl., S195, S195, Apr. 2021
  (公社)日本超音波医学会, Japanese
• 最近の超音波による癌治療 その可能性と課題
  近藤 隆; 鈴木 亮; 佐々木 東; 滝口 満喜, Thermal Medicine, 36, 3, 75, 90, Sep. 2020
  (一社)日本ハイパーサーミア学会, Japanese
• LC-MS/MSを用いたイヌ尿中メタネフリンおよびノルメタネフリン測定
  井上 裕美子; 佐々木 東; 池中 良徳; 一瀬 貴大; 笹岡 一慶; 大菅 辰幸; 中山 翔太; 森下 啓太郎; 大田 寛; 石塚 真由美; 滝口 満喜, 日本獣医学会学術集会講演要旨集, 162回, 470, 470, Aug. 2019
  (公社)日本獣医学会, Japanese
• 低強度パルス超音波照射による毛髪細胞刺激
  佐々木 東; 工藤 信樹; 大田 寛; 滝口 満喜, 超音波医学, 46, Suppl., S579, S579, Apr. 2019
  (公社)日本超音波医学会, Japanese
• どうすれば超音波の生物学的作用に関する実験ができるか(その16) 演習問題 実験動物を用いた超音波照射実験
  佐々木 東, 超音波医学, 46, 1, 59, 61, Jan. 2019
  (公社)日本超音波医学会, Japanese
• Low-intensity pulsed ultrasound modifies effects of a myelin-related growth inhibitor and enhances neurite re-growth
  Noboru Sasaki; Nobuki Kudo; Hiroshi Ohta; Mitsuyoshi Takiguchi, 2019 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), 1308, 1310, 2019
  English
• 蛋白喪失性腸症の犬33例からの腸リンパ管拡張症の診断と治療に関する考察
  永田 矩之; 大田 寛; 横山 望; ニサ・ホイルン; 佐々木 東; 森下 啓太郎; 滝口 満喜, 北海道獣医師会雑誌, 62, 8, 334, 334, Aug. 2018
  (公社)北海道獣医師会, Japanese
• 神経筋接合部検査としてアイスパックテストを試みた重症筋無力症の犬の1例
  山田 有紗; 笹岡 一慶; 大田 寛; 立花 由莉加; 大菅 辰幸; 佐々木 東; 森下 啓太郎; 滝口 満喜, 北海道獣医師会雑誌, 62, 8, 335, 335, Aug. 2018
  (公社)北海道獣医師会, Japanese
• 犬の粘液腫様変性性僧帽弁疾患における心エコー図法による左心室-大動脈カップリングの推定
  大菅 辰幸; 佐々木 東; 森下 啓太郎; 大田 寛; 滝口 満喜, 北海道獣医師会雑誌, 62, 8, 335, 335, Aug. 2018
  (公社)北海道獣医師会, Japanese
• 神経症状を主訴とした悪性中皮腫の猫の1例
  大村 侑己; 大田 寛; 小林 篤史; 笹岡 一慶; 道下 明日香; 大菅 辰幸; 佐々木 東; 森下 啓太郎; 滝口 満喜, 北海道獣医師会雑誌, 62, 8, 340, 340, Aug. 2018
  (公社)北海道獣医師会, Japanese
• 鼻腔内真菌感染症に対しクロトリマゾール灌流および注入療法を実施した犬の1例
  大谷 豪; 大田 寛; 岩木 有香; 細谷 謙次; 新坊 弦也; 佐々木 東; 森下 啓太郎; 滝口 満喜, 北海道獣医師会雑誌, 62, 8, 344, 344, Aug. 2018
  (公社)北海道獣医師会, Japanese
• 経頭蓋超音波ドプラ法により局所的な脳循環動態を評価し得た右中大脳動脈梗塞の犬の1例
  笹岡 一慶; 大田 寛; 石塚 友人; 大菅 辰幸; 立花 由莉加; 森下 啓太郎; 佐々木 東; 滝口 満喜, 北海道獣医師会雑誌, 62, 8, 341, 341, Aug. 2018
  (公社)北海道獣医師会, Japanese
• Shear Wave Elastography(SWE)を用いた犬の肝硬度測定
  田村 昌大; 大田 寛; 佐々木 東; 賀川 由美子; 滝口 満喜, 獣医畜産新報, 71, 7, 496, 497, Jul. 2018
  文永堂出版(株), Japanese
• 低強度パルス超音波による神経軸索の伸展制御の試み
  佐々木 東; 工藤 信樹; 大田 寛; 滝口 満喜, 超音波医学, 45, Suppl., S575, S575, Apr. 2018
  (公社)日本超音波医学会, Japanese
• 超音波と膀胱内注入療法を組み合わせた膀胱癌治療法の開発
  佐々木東; 中山翔太; 森下啓太郎; 中村健介; 大田寛; 水川葉月; 池中良徳; 石塚真由美; 滝口満喜, 日本獣医学会学術集会講演要旨集, 160回, 461, 461, Aug. 2017
  (公社)日本獣医学会, Japanese
• 3次元培養でのシスプラチンと超音波 マイクロバブルの併用
  佐々木 東; Moonen Chrit; 滝口 満喜, 超音波医学, 43, 5, 673, 673, Sep. 2016
  (公社)日本超音波医学会, Japanese
• 超音波による細胞周期変動を利用した増感放射線療法の可能性
  藤沢 眞代; 佐々木 東; 安井 博宣; 工藤 信樹; 滝口 満喜, 超音波医学, 43, 5, 679, 679, Sep. 2016
  (公社)日本超音波医学会, Japanese
• 膀胱癌を模した3次元培養系でのシスプラチンデリバリー
  佐々木 東; 工藤 信樹; 滝口 満喜, 超音波医学, 43, 5, 679, 679, Sep. 2016
  (公社)日本超音波医学会, Japanese
• シスプララチンデリバリーの効果が及ぶ距離
  佐々木 東; 工藤 信樹; 中村 健介; 森下 啓太郎; 大田 寛; 滝口 満喜, 超音波医学, 43, Suppl., S544, S544, Apr. 2016
  (公社)日本超音波医学会, Japanese
• ミニチュア・ダックスフンドの炎症性結直腸ポリープ症例の結直腸粘膜におけるToll‐like receptor2,4の局在解析
  横山望; 大田寛; 賀川由美子; 山崎淳平; 市居修; KHOIRUN Nisa; 森田智也; 大菅辰幸; 佐々木東; 森下啓太郎; 中村健介; 滝口満喜, 日本獣医学会学術集会講演要旨集, 158th, 402, 402, 30 Aug. 2015
  (公社)日本獣医学会, Japanese
• ドラッグデリバリーを可視化する培養系の開発
  佐々木 東; 滝口 満喜; Bos Clemens; Moonen Chrit, 超音波医学, 42, Suppl., S476, S476, Apr. 2015
  (公社)日本超音波医学会, Japanese
• バブルを使った診断と治療 パルス超音波を用いたソノポレーションの実現に向けたいくつかの基礎的検討
  工藤 信樹; 佐々木 東; 滝口 満喜, 超音波医学, 39, Suppl., S174, S174, Apr. 2012
  (公社)日本超音波医学会, Japanese
• 診断装置によるソノポレーションの特徴と条件設定
  佐々木 東; 中村 健介; 工藤 信樹; 滝口 満喜, 超音波医学, 39, 2, 226, 227, Mar. 2012
  (公社)日本超音波医学会, Japanese
• Enhanced Cytotoxic Effect of Cisplatin Using Diagnostic Ultrasound and Microbubbles In Vitro
  Sasaki Noboru; Nakamura Kensuke; Murakami Masahiro; Lim Sue Yee; Ohta Hiroshi; Yamasaki Masahiro; Takiguchi Mitsuyoshi, 11TH INTERNATIONAL SYMPOSIUM ON THERAPEUTIC ULTRASOUND, 1481, 307, 310, 2012, [Peer-reviewed]
• 超音波診断装置および超音波造影剤による抗がん剤の抗腫瘍効果の増強
  佐々木 東; 中村 健介; 工藤 信樹; 滝口 満喜, 超音波医学, 38, 6, 674, 674, Nov. 2011
  (公社)日本超音波医学会, Japanese
• パルス超音波と微小気泡によるシスプラチンの抗腫瘍効果増強の基礎的知見
  佐々木 東; 中村 健介; 村上 正紘; 大田 寛; 山崎 真大; 工藤 信樹; 滝口 満喜, 超音波医学, 38, 3, 338, 338, May 2011
  (公社)日本超音波医学会, Japanese
• 診断用超音波とマイクロバブルによるドラッグデリバリーのin vitroでの最適化
  佐々木 東; 中村 健介; 村上 正紘; Kumara Badula; 大田 寛; 山崎 真大; 工藤 信樹; 滝口 満喜, 超音波医学, 38, Suppl., S316, S316, Apr. 2011
  (公社)日本超音波医学会, Japanese
• 第二世代超音波造影剤ソナゾイドを用いた造影超音波検査による犬の肝臓および脾臓腫瘤の診断に関する研究
  NAKAMURA KENSUKE; TAKAGI SATOSHI; YAMASAKI MASAHIRO; OTA HIROSHI; SASAKI NOBORU; MURAKAMI MASAHIRO; TAMURA YU; TAKIGUCHI MITSUYOSHI, 日本獣医学会学術集会講演要旨集, 151回, 82, 82, Mar. 2011
  (公社)日本獣医学会, Japanese
• 微小気泡存在下での診断用超音波照射によるシスプラチンの抗腫瘍効果増強の検討
  SASAKI AZUMA; NAKAMURA KENSUKE; MURAKAMI MASAHIRO; BANDULA KUMARA; TAMURA YU; OTA HIROSHI; YAMASAKI MASAHIRO; KUDO NOBUKI; TAKIGUCHI MITSUYOSHI, 日本獣医学会学術集会講演要旨集, 150回, 297, 297, Sep. 2010
  (公社)日本獣医学会, Japanese
• 超音波診断装置と微小気泡によるシスプラチンの抗腫瘍効果の増強
  佐々木 東; 中村 健介; 村上 正紘; Kumara Bandula; 大田 寛; 山崎 真大; 工藤 信樹; 滝口 満喜, 超音波医学, 37, Suppl., S322, S322, Apr. 2010
  (公社)日本超音波医学会, Japanese
• 犬の脾臓腫瘤におけるソナゾイド造影超音波検査の有用性
  NAKAMURA KENSUKE; YAMASAKI MASAHIRO; OTA HIROSHI; SASAKI NOBORU; MURAKAMI MASAHIRO; TAKIGUCHI MITSUYOSHI, 日本獣医学会学術集会講演要旨集, 148回, 268, 268, Sep. 2009
  (公社)日本獣医学会, Japanese
• 超音波検査により求めた正常なビーグル犬の甲状腺体積と体重の相関
  佐々木 東; 中村 健介; 大田 寛; 山崎 真大; 滝口 満喜, 動物臨床医学会年次大会プロシーディング, 29回, 3, 29, 32, Nov. 2008
  動物臨床医学会, Japanese
• 犬の肝臓における造影超音波検査の有用性の検討
  NAKAMURA KENSUKE; SASAKI HIGASHI; YOSHIKAWA MUNEYOSHI; O KOJAKU; OTA HIROSHI; YAMASAKI MASAHIRO; TAKIGUCHI MITSUYOSHI, 日本獣医学会学術集会講演要旨集, 146回, 265, 265, Sep. 2008
  (公社)日本獣医学会, Japanese
• 犬の甲状腺機能低下症の診断基準としての化学発光免疫測定法(CLIA法)による甲状腺ホルモン値
  佐々木 東; 山崎 真大; 大田 寛; 田島 誉士; 前出 吉光, 北海道獣医師会雑誌, 50, 8, 77, 77, Aug. 2006
  (公社)北海道獣医師会, Japanese

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  27 Oct. 2020 - 31 Mar. 2024
  中尾 亮; 佐々木 東; 邱 永晋
  昨年度に引き続き、マダニ細胞作出のため実験動物を用いたマダニ吸血試験を行い、マダニ卵を回収した。これまでに用いてきたフタトゲチマダニ（Haemaphysalis longicornis）（高知株・単為生殖系統）に加え、キチマダニ（Haemaphysalis flava）、ヤマトマダニ（Ixodes ovatus）、タカサゴキララマダニ（Amblyomma testudinarium）を新たに吸血実験に用いた。タカサゴキララマダニにおいては、飽血個体においても実験室条件下では産卵がみられなかった。他種マダニについては細胞作出に十分なマダニ卵を回収できた。その後、L15培地、L-15B培地、TNM-FH培地、TC-100培地を用いて初代培養細胞の継代培養を開始した。マダニ細胞の生存確認のために、マダニのハウスキーピング遺伝子の発現をモニタリングできるRT-PCR系を開発した。本法を用いることで、一部の細胞ロットでは培養開始から約6ヶ月後においても、ハウスキーピング遺伝子の発現が確認でき、活発な分裂が見られないものの細胞が生存していることが確認できた。また、一部の細胞ロットでは、CoxiellaおよびRickettsiaの遺伝子配列が得られ、細胞に共生していることが示唆された。
  マダニ人工吸血システムの構築のため、シリコン膜の作製条件を引き続き検討した。これまでに用いてきたレンズペーパーおよびゴールドビーターズ・スキンに加え、新たに和紙をシリコン膜の基材として使用した。また、マダニ吸血刺激作用が報告されている二酸化炭素を吸血ユニット内に満たす器具を開発し、人工吸血装置の改良を行なった。フタトゲチマダニ、ヤマトマダニ、タカサゴキララマダニを用いて吸血試験を行なったものの、これまでに飽血に到る成果は得られていない。
  Japan Society for the Promotion of Science, Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)), Hokkaido University, 20KK0151
• Elucidation of mechanical and biological effects of oscillating microbubbles on capillary endothelial cells and extravasation
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2020 - 31 Mar. 2023
  工藤 信樹; 鈴木 亮; 松崎 典弥; 佐々木 東
  血管内に投与した薬剤を超音波の照射により血管外の組織に漏出させる超音波薬物送達法では，薬剤とともに投与される微小気泡が超音波の照射下で血管に与える作用を明らかにする必要がある．本年度は主に２つの方法により解明に向けた準備作業を行った．
  ①血管の物理特性を模擬するゲルファントムの開発
  微細径のタングステンワイヤを張った型にアクリルアミドゲルを流し込み，ゲル硬化後にワイヤを引き抜くことにより最小直径約10ミクロンの内腔を有する毛細血管ファントムを作成する技術を開発した．微細管腔への微小気泡導入は，初期的にはゲルからワイヤを引き抜く作業を微小気泡の懸濁液内で行うことにより実現できる．また，ゲルの浸透圧を気泡懸濁液の浸透圧よりも低く設定することにより持続的に管腔内に気泡を引き込む流れが形成できることを発見した．これにより，超音波照射により気泡が壊れても新たな気泡が自動的に導入され，繰り返し実験できるようになった．
  ②生体の組織構造を模擬する3次元培養細胞血管ファントムの開発
  コラーゲンゲルに懸濁した血管内皮細胞（HUVEC）を血管内皮増殖因子（VEGF）を加えた培地内で3次元培養することにより毛細血管ファントムを作成する手法を開発し，安定な作成プロセスを検討した．血管内腔に取り込んだ気泡が超音波照射下で生じるダイナミクスを高速度観察する手法，薬剤の漏出や内皮細胞に生じる損傷を可視化する蛍光観察手法を開発した．さらに，血管内に模擬薬剤を導入し，超音波を照射していない状態での漏出が薬剤の分子量によってどのように変化するかを調べた．
  さらに，次年度以降に向けた準備作業として，生体内の毛細血管を用いて超音波照射下での気泡のダイナミクスを観察する手法について文献調査を行い，ラットなどの腸間膜を使う手法について検討した．
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20H04542
• 膀胱内ソノポレーションによる膀胱癌局所治療法の開発
  科学研究費助成事業 若手研究
  01 Apr. 2019 - 31 Mar. 2022
  佐々木 東
  膀胱癌の新たな低侵襲的な治療法として、膀胱内ソノポレーションによるドラッグデリバリー法の開発を行っている。本申請では（1） 3次元培養系でのデリバリー定量による治療の最適条件の探索；（2）正常犬を用いた膀胱内ソノポレーションの安全性確認；（3）膀胱腫瘍罹患犬での膀胱内ソノポレーションの安全性確認および治療プロトコールの確定、を目指している。このうち、本年度は（1）の治療条件の探索を行った。過去に報告のある単相培養でのデリバリー定量、そして3次元培養系でのデリバリー定量の結果から、ドラッグデリバリーに最も影響するのは超音波条件よりも繰り返し回数と考えられた。さらに、予備的検討として犬の摘出膀胱を用いた膀胱内ソノポレーションによるドラッグデリバリーを行い、デリバリー定量を行った。その結果、単回の照射でも膀胱粘膜中の薬剤濃度の上昇が認められた。以上より、1日あたりの治療回数は1回でも可能であるが、複数回治療が望ましいと予想される。膀胱内に薬剤を投与する場合、一部の薬剤は膀胱粘膜から吸収され全身作用を及ぼすことが知られている。したがって、膀胱内に注入する薬剤濃度および治療の回数・間隔を検討することが、治療効果の高い安全な膀胱内ソノポレーション治療法に不可欠である。今後は（2）の正常犬を用た膀胱内ソノポレーションにより単回もしくは複数回治療の副作用を検討し、より安全かつ治療効果の高い治療プロトコールの設定を行う。
  日本学術振興会, 若手研究, 北海道大学, 19K15971
• Elucidation of mechanisms and expansion of application range of sonoporation by in situ observation of bubble-cell interaction
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
  01 Apr. 2017 - 31 Mar. 2021
  Kudo Nobuki
  Sonoporation and blood-brain (tumor) barrier (BBB/BTB) opening techniques achieve local drug delivery by ultrasound irradiation with microbubbles. The former delivers drugs into cells by increasing the cell membranes permeability, and the latter facilitates drug transfer from blood to perivascular tissues by loosening vascular endothelial cell junctions. In this study, we created three models that simulate the in vivo situation in which three types of cells exist: superficial cells on the soft tissue, vascular endothelial cells that manage drug transfer from the blood, and dendritic cells that are responsible for immunity. The cell-bubble interaction in the model was observed in situ using high-speed confocal microscope to elucidate the mechanisms of sonoporation and blood barrier opening and their dependence on ultrasound irradiation conditions.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 17H00864
• Sono-mechanotherapy for neurite outgrowth
  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
  29 Jun. 2018 - 31 Mar. 2020
  Mitsuyoshi Takiguchi
  Axon regeneration is crucial for the functional recovery after spinal cord injury. Myelin-related growth inhibitors, such as Nogo-A, inhibit neurites regrowth and elongation. Low-intensity pulsed ultrasound (LIPUS) is known to show neuroprotective effects in neurodegenerative diseases. In the present study, we evaluated the feasibility of LIPUS for enhancing axon regeneration in the presence of Nogo-A. Low-intensity pulsed ultrasound was exposed to rat cortical neurons in vitro after Nogo-A treatment. The total length of neurites per cell in LIPUS group was significantly larger than that of non-LIPUS group. There was no significant difference in the number of neurites. The results suggest that LIPUS may enhance the elongation of neurites in the presence of Nogo-A while may not affect on neurites sprouting and branching. This preliminary study implies the feasibility of LIPUS for axonal regeneration.
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 18K19255
• 2018年度秋山記念生命科学研究助成 奨励
  Apr. 2018 - Mar. 2019
• 第36回カシオ科学振興財団研究助成
  Apr. 2018 - Mar. 2019
• Spatial-Temporal profile of ultrasound-mediated cisplatin delivery
  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
  01 Apr. 2016 - 31 Mar. 2018
  SASAKI Noboru
  Ultrasound-triggered microbubble cavitation is a promising tool for drug and gene delivery in cancer therapy. We evaluated the temporal and spatial profile of cisplatin delivery by ultrasound-triggered microbubble cavitation. We used a bladder cancer mimicking 3D culture model for this study. Single treatment of ultrasound-triggered microbubble cavitation increased an intracellular concentration of cisplatin at the thickness of 100 μm. The duration of enhanced delivery was 1 hr. Based on the distance and duration of delivery, we further tested the feasibility of repetition of the treatment. Triple treatment increased the effective distance by 2-fold. Our results clearly showed spatial and temporal profile of delivery by ultrasound-triggered microbubble cavitation in a tumor-mimicking structure. The results of this study suggest that ultrasound-triggered microbubble cavitation can be repeatable and is promising for cancer treatment.
  Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, 16K18799
• Novel cancer therapy for spontaneous animal tumor using ultrasound irradiation with microbubble
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2014 - 31 Mar. 2017
  TAKIGUCHI MITSUYOSHI; KUDO Nobuki
  This study revealed that sonoporation, the combination of ultrasound and microbubbles, enhances the antitumor effect of a chemotherapeutic agent with minimum invasiveness in preclinical canine thyroid and bladder cancer models. Moreover, the results of this study clarified the mechanism of sonoporation. This preclinical study may contribute to establish sonoporation as a theranostic tool in cancer therapy.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 26292155
• ホーユー科学財団平成28年度研究助成
  Apr. 2016 - Mar. 2017
• The development of a novel sensitizing radiation therapy in conjunction with microbubbles and ultrasound exposure
  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
  01 Apr. 2014 - 31 Mar. 2016
  TAKIGUCHI Mitsuyoshi; SASAKI Noboru
  The purpose of this study is to clarify the sensitizing effect of irradiation-induced apoptosis after ultrasound exposure in the presence of microbubbles. Mouse sequemous cell carcinoma cell was irradiated right after the ultrasonic exposure with microbubbles resulted in sensitizing effect of 1.1. After considering optimal irradiation timing in the light of the effect of cell cycle variation of ultrasound exposure, it was suggested that 9 hours after the ultrasound exposure was suitable. However, the sensitizing effect of irradiation-induced apoptosis remained 1.1. Further study is needed using 3-dimensional cell culture system.
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 26660233