研究者データベース

研究者情報

マスター

アカウント(マスター)

  • 氏名

    佐々木 東(ササキ ノボル), ササキ ノボル

所属(マスター)

  • 獣医学研究院 獣医学部門 臨床獣医科学分野

所属(マスター)

  • 獣医学研究院 獣医学部門 臨床獣医科学分野

独自項目

syllabus

  • 2020, 臨床疾病学特論, Advanced Lecture on Veterinary Clinical Diseases, 博士後期課程, 獣医学院
  • 2020, 総合専門臨床特論, Advanced and Comprehensive Studies on Integrated Specialized Veterinary Clinical Medicine, 博士後期課程, 獣医学院
  • 2020, 獣医内科学特論, Advanced Lecture on Veterinary Internal Medicine, 博士後期課程, 獣医学院
  • 2020, 伴侶動物獣医療実習Ⅰ, Practice in Companion Animal Medicine I, 学士課程, 獣医学部, 伴侶動物、内科、外科、検査、診断、治療
  • 2020, 伴侶動物獣医療実習Ⅱ, Practice in Companion Animal Medicine II, 学士課程, 獣医学部, 伴侶動物、内科、外科、検査、診断、治療
  • 2020, 総合獣医療実習, Practice in Comprehensive Veterinary Medicine, 学士課程, 獣医学部, 臨床病理、画像診断、細胞診、病理解剖、麻酔
  • 2020, 夜間・救急獣医療実習Ⅰ, Practice in Night Times and Emergency Medicine I, 学士課程, 獣医学部, 夜間・休日診療、救急処置
  • 2020, プレクリニカル実習, Practice in Preclinical Medicine, 学士課程, 獣医学部, 臨床診断学、獣医内科学、獣医外科学、繁殖学、画像診断学、伴侶動物、産業動物

timetable

  • 博士後期課程, 獣医学研究科, 2020, 先端獣医科学特論A 獣医内科学特論
  • 博士後期課程, 獣医学研究科, 2020, 先端獣医科学特論A 国際獣医科学特論:臨床獣医学
  • 学士課程, 獣医学部, 2020, 放射線獣医療・画像診断学実習
  • 学士課程, 獣医学部, 2020, 内科学実習
  • 学士課程, 獣医学部, 2020, 伴侶動物獣医療実習
  • 学士課程, 獣医学部, 2020, 伴侶動物夜間・救急獣医療実習
  • 学士課程, 獣医学部, 2020, コミュニケーション論演習
  • 学士課程, 獣医学部, 2020, アドバンスト演習

researchmap

プロフィール情報

学位

  • 獣医学博士(北海道大学)

プロフィール情報

  • 佐々木
  • ID各種

    201501027810194155

業績リスト

研究分野

  • ライフサイエンス / 獣医学
  • ライフサイエンス / 生体医工学

経歴

  • 2015年01月 - 現在 北海道大学大学院獣医学研究科 助教
  • 2013年03月 - 2014年12月 University Medical Center Utrecht, Radiology, Postdoctoral Fellow
  • 2012年04月 - 2013年03月 北海道大学 大学院獣医学研究科 客員研究員
  • 2012年05月 - 2013年02月 University Medical Center Utrecht, Radiology, Guest Researcher

学歴

  •         - 2012年03月   北海道大学   大学院獣医学研究科   博士課程 修了
  •         - 2008年03月   北海道大学   獣医学部 卒業

受賞

  • 2021年06月 日本獣医学会 2020年JVMS優秀論文賞
     An area ratio of thyroid gland to common carotid artery for evaluating the thyroid gland size 
    受賞者: 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
  • 2011年11月 第10回日本超音波治療研究会 若手研究者の部 優秀賞
     
    受賞者: 佐々木東
  • 2011年09月 日本超音波医学会第41回北海道地方会 優秀演題賞
     
    受賞者: 佐々木東

論文

  • Shingo Miki, Kensuke Nakamura, Tomoya Morita, Tatsuyuki Osuga, Sei Kawamoto, Noboru Sasaki, Mitsuyoshi Takiguchi
    American journal of veterinary research 82 10 795 - 801 2021年10月 
    OBJECTIVE: To determine the effects of IV administration of pimobendan on hemodynamic indices and indices of left atrial (LA) longitudinal strain by speckle-tracking echocardiography in healthy dogs. ANIMALS: 6 healthy Beagles. PROCEDURES: After the dogs were anesthetized, the right heart was catheterized and 2-D conventional and speckle-tracking echocardiography were performed before and after IV administration of 0.15 mg of pimobendan/kg. Speckle-tracking echocardiography was performed to assess the 3 LA phasic functions through LA deformation (longitudinal strain and strain rate) and volumetric analyses. RESULTS: Pimobendan significantly increased stroke volume and cardiac output and decreased systemic vascular resistance. Pimobendan significantly improved left ventricular function assessed by the Tei index and LA booster pump function assessed by LA longitudinal strain and change in fractional volume during atrial systole. Indices of LA reservoir and conduit function were unchanged. CONCLUSIONS AND CLINICAL RELEVANCE: In healthy dogs, IV administration of pimobendan improved the indices of LA booster pump function but had no effect on the indices of LA reservoir and conduit functions. Further studies are needed to validate whether these results can be extrapolated to dogs with myxomatous mitral valve disease.
  • Rommaneeya Leela-Arporn, Hiroshi Ohta, Genya Shimbo, Noboru Sasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 83 9 1459 - 1464 2021年09月27日 
    The size of canine focal liver lesions (FLLs) is known to be one of the predicting criteria for malignancy. However, there are discrepancies for the measurement of maximum lesion size, resulting in contradicting results among studies and incidences of false positive outcomes. Thus far, the morphometric changes of FLLs for distinguishing malignancy from benignancy remains undocumented. This study aimed to investigate morphometric characteristics of FLLs using computed tomography (CT). CT images of 40 dogs with histopathological confirmation of 49 liver lesions, including 39 hepatocellular carcinomas and 10 nodular hyperplasias were retrospectively reviewed. The morphometric parameters including size (long and short axis diameters measured on transverse image), shape (measured by long to short axis (L/S) ratio), volume, and surface appearance of a liver lesion were evaluated using univariate and stepwise multivariate analyses, respectively. The results of univariate analysis showed that long and short axis diameters, L/S ratio, volume, and surface appearance of a lesion were significantly different between hepatocellular carcinomas and nodular hyperplasias. Multivariate analysis revealed that short axis diameter (>3.30 cm; odds ratio (OR): 36.1, 95% confidence interval (CI): 3.36-387.05, P=0.0031) and L/S ratio (>1.23; OR: 18.1, 95% CI: 1.61-205.12, P=0.0191) were independent predictors of malignancy, with the area under the curve of 0.9154. These results suggest that the combination of short axis diameter and L/S ratio is a promising tool for predicting liver malignancy with outstanding discriminating ability.
  • 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 2021年09月17日 
    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.
  • Kazuki Kojima, Tomohito Ishizuka, Noboru Sasaki, Kensuke Nakamura, Mitsuyoshi Takiguchi
    Veterinary anaesthesia and analgesia 48 5 654 - 662 2021年09月 
    OBJECTIVE: To evaluate the systemic cardiovascular effects of dose escalating administration of norepinephrine in healthy dogs anesthetized with isoflurane. STUDY DESIGN: Experimental study. ANIMALS: A total of six adult laboratory Beagle dogs, 10.5 (9.2-12.0) kg [median (range)]. METHODS: Each dog was anesthetized with isoflurane at an end-tidal concentration of 1.7%, mechanically ventilated and administered a continuous rate infusion of rocuronium (0.5 mg kg-1 hour-1). Each dog was administered incremental dose rates of norepinephrine (0.05, 0.125, 0.25, 0.5, 1.0 and 2.0 μg kg-1 minute-1), and each dose was infused for 15 minutes. Cardiovascular variables were recorded before administration and at the end of each infusion period. RESULTS: Norepinephrine infusion increased mean arterial pressure (MAP), cardiac output (CO) and oxygen delivery in a dose-dependent manner. Systemic vascular resistance did not significantly change during the experiment. Stroke volume increased at the lower dose rates and heart rate increased at the higher dose rates. Oxygen consumption and lactate concentrations did not significantly change during infusions. CONCLUSIONS: In dogs anesthetized with isoflurane, norepinephrine increased MAP by increasing the CO. CO increased with a change in stroke volume at lower dose rates of norepinephrine. At higher dosage, heart rate also contributed to an increase in CO. Norepinephrine did not cause excessive vasoconstriction that interfered with the CO during this study. CLINICAL RELEVANCE: Norepinephrine can be useful for treating hypotension in dogs anesthetized with isoflurane.
  • Masahiro Tamura, Hiroshi Ohta, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Mitsuyoshi Takiguchi
    Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association 62 4 483 - 489 2021年07月 
    Two-dimensional shear wave elastography (2D-SWE) can be used to quantitatively evaluate the elastic modulus of the liver as shear wave velocity (SWV), which can noninvasively predict clinically relevant hepatic fibrosis in both dogs and humans. However, extrahepatic biliary obstruction (EHBO), regardless of the presence of clinically relevant hepatic fibrosis, can influence SWVs in humans and thus may interfere with hepatic fibrosis prediction using 2D-SWE in dogs. The aim of this prospective, observational, and one-group pretest-posttest study is to investigate whether SWV measured by 2D-SWE displays a difference between dogs with and without EHBO. A total of 20 dogs were included (7 with EHBO and 13 with gallbladder pathology but no EHBO) that underwent preoperative SWV measurement using 2D-SWE. In all dogs, stages of hepatic fibrosis were evaluated histopathologically using a scoring scheme. In addition, postoperative SWVs in dogs with EHBO relieved via laparotomy were also evaluated. The median (range) SWVs in the dogs with and without EHBO were 1.91 (1.81-2.54) m/s and 1.57 (1.37-1.64) m/s, respectively. Although there was no significant difference in the histopathological hepatic fibrosis stages between the dogs with and without EHBO, the preoperative SWVs in the dogs with EHBO were significantly higher than in dogs without EHBO (P = .0004), and SWVs were found to decrease significantly after surgery (P = .0097). This study demonstrates that EHBO can increase the SWV of dogs without clinically relevant hepatic fibrosis and can interfere with the prediction of noninvasive hepatic fibrosis using 2D-SWE.
  • Tomohiro Suzuki, Anri Hirai, Kraisiri Khidkhan, Collins Nimako, Takahiro Ichise, Kazuki Takeda, Hazuki Mizukawa, Shouta M M Nakayama, Kei Nomiyama, Nobuhiko Hoshi, Mizuki Maeda, Tetsushi Hirano, Kazuyoshi Sasaoka, Noboru Sasaki, Mitsuyoshi Takiguchi, Mayumi Ishizuka, Yoshinori Ikenaka
    Pesticide biochemistry and physiology 175 104847 - 104847 2021年06月 
    Fipronil is a phenylpyrazole insecticide that is widely used as a pesticide and a veterinary drug, although studies suggest that it could be toxic to mammals. The objectives of this study were to examine the pharmacokinetic profile of fipronil in mice, dogs, and cats, and to evaluate its effects on emotional and cognitive behaviors of dogs and cats using the data obtained from mice. The assessment of in vivo kinetics of fipronil was conducted in mice and dogs. We also performed behavioral tests (elevated plus-maze and Y-maze) and measured the levels of neurotransmitters in mice exposed to fipronil. In addition, the in vitro metabolism of fipronil were evaluated using liver microsomes of rats, mice, dogs, and cats. The results revealed that fipronil is distributed throughout the body (blood, brain, adipose tissue, and liver) of mice after dermal application. It was metabolized to fipronil sulfone primarily in the liver. The data on kinetics show that both fipronil and fipronil sulfone have a longer half-life in dogs and cats than in mice. The behavioral tests indicated that fipronil and fipronil sulfone could affect emotional and cognitive behaviors and alter the levels of neurotransmitters (dopamine in the striatum and serotonin in the hippocampus) in mice. Furthermore, we found that dogs and cats have a low ability to metabolize fipronil than mice and rats. However, further comprehensive studies are needed to determine whether fipronil affects the emotional and cognitive behaviors when administered to dogs and cats. To the best of our knowledge, this is the first study to examine the pharmacokinetic data and verify the effects of fipronil on emotional and cognitive behaviors of dogs and cats using the data obtained from mice.
  • 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 2021年04月09日 
    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.
  • Hiroshi Ohta, Noriyuki Nagata, Nozomu Yokoyama, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 83 3 378 - 384 2021年03月11日 
    To date, little is known about the prognostic significance of ultrasonographic findings in dogs with protein-losing enteropathy (PLE). The aim of this retrospective study was to examine the prognostic value of ultrasonographic findings in dogs with PLE. A total of 26 dogs with PLE were included: 20 dogs with chronic enteropathy and 6 dogs with gastrointestinal lymphoma. The presence of small intestinal dilatation was associated with shorter survival time in dogs with PLE (P=0.003). The presence of hyperechoic intestinal mucosal striations was associated with longer survival time in dogs with PLE (P=0.0085). The results of the current study indicate that the presence of small intestinal dilatation might be associated with poor prognosis in dogs with PLE.
  • Tatsuyuki Osuga, Tomoya Morita, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 35 1 78 - 87 2021年01月 
    BACKGROUND: The effective arterial elastance (Ea) to left ventricular (LV) end-systolic elastance (Ees) ratio (Ea/Ees) is an index of the interaction between LV and systemic arterial systems, left ventricular-arterial coupling (VAC). The Ea is an index of total arterial load of the LV, whereas Ees is an index of LV systolic function. In humans, inappropriate VAC based on increased Ea/Ees estimated using echocardiography is associated with more advanced heart disease severity. HYPOTHESIS: Left ventricular-arterial coupling assessed by echocardiographic estimation of Ea/Ees is associated with disease severity in dogs with myxomatous mitral valve disease (MMVD). ANIMALS: Ninety MMVD dogs and 61 healthy dogs. METHODS: Prospective cross-sectional study. The MMVD dogs were classified into stages B1, B2, or C according to American College of Veterinary Internal Medicine guidelines. Effective arterial elastance was echocardiographically estimated using the formula: mean blood pressure/(forward stroke volume/body weight). End-systolic elastance was echocardiographically estimated using the formula: mean blood pressure/(LV end-systolic volume/body weight). The ratio Ea/Ees was calculated. RESULTS: The ratio Ea/Ees was higher in stage B2 dogs than in healthy dogs and dogs stage B1 (both P < .0001), and higher in stage C dogs than in healthy dogs and dogs in the other 2 stages (healthy vs C and B1 vs C, P < .0001; B2 vs C, P = .0005). Multivariable logistic regression analysis showed that Ea/Ees and the peak velocity of early diastolic transmitral flow to isovolumic relaxation time ratio were independent predictors of stage C among echocardiographic indices in MMVD dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Inappropriate VAC assessed by echocardiographically estimated Ea/Ees is associated with advanced disease severity in dogs with MMVD.
  • Hiroto Takeuchi, Satoru Konnai, Naoya Maekawa, Satoshi Takagi, Hiroshi Ohta, Noboru Sasaki, Sangho Kim, Tomohiro Okagawa, Yasuhiko Suzuki, Shiro Murata, Kazuhiko Ohashi
    Frontiers in veterinary science 8 656715 - 656715 2021年 
    Cancer cells can evade host immune systems via multiple mechanisms. Transforming growth factor beta 1 (TGF-β1) is an immunosuppressive cytokine that induces regulatory T cell (Tregs) differentiation and is involved in immune evasion mechanisms in cancer. The inhibition of the TGF-β1 signaling pathway can suppress cancer progression and metastasis through the modulation of anticancer immune responses. However, to best of our knowledge, no implementation of treatments targeting TGF-β1 has been reported in dog cancers. This study aimed to examine whether TGF-β1 is upregulated in canine cancers. We measured TGF-β1 concentrations in culture supernatants of canine melanoma cell lines and in serum samples from dogs with oral malignant melanoma. TGF-β1 production was observed in several cell lines, and serum TGF-β1 levels were elevated in dogs with oral malignant melanoma. Interestingly, the addition of recombinant TGF-β1 to canine peripheral blood mononuclear cell cultures decreased Th1 cytokine production and increased differentiation of CD4+CD25+Foxp3+ lymphocytes, suggesting that TGF-β1 is immunosuppressive in canine immune systems. We developed a decoy receptor for TGF-β, namely TGF-βRII-Ig, by identifying an open reading frame of the canine TGFBR2 gene. TGF-βRII-Ig was prepared as a recombinant fusion protein of the extracellular region of canine TGF-βRII and the Fc region of canine IgG-B. As expected, TGF-βRII-Ig bound to TGF-β1. In the presence of TGF-β1, the treatment with TGF-βRII-Ig increased Th1 cytokine production and decreased the differentiation of CD4+CD25+Foxp3+ lymphocytes. Our results suggest that TGF-βRII-Ig competitively inhibits the immunosuppressive effects of TGF-β1 and thereby activates immune responses. This study demonstrated the potential of TGF-βRII-Ig as a novel biologic for canine melanoma.
  • Lesa A Thompson, Atsuya Morita, Shoko Murakami, Noboru Sasaki, Miou Murashita, Ryou Yamazaki, Atsushi Kobayashi, Takashi Kimura, Mitsuyoshi Takiguchi
    Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 32 6 953 - 956 2020年11月 
    An 8-mo-old male African pygmy hedgehog was anorectic and ataxic; physical examination revealed tetraparesis and a gangrenous left hindlimb. Analgesic and supportive care were administered, but the animal died 3 d after presentation. Postmortem examination revealed a histiocytic sarcoma in a mesenteric lymph node with metastasis to several organs, multifocal vacuolation in the cerebral and cerebellar white matter, and a meningioma in the left lateral ventricle. We diagnosed wobbly hedgehog syndrome (WHS) with disseminated histiocytic sarcoma and lateral ventricular meningioma. Ventricular meningioma, a rare neoplasm in veterinary and human patients, has not been reported previously in hedgehogs, to our knowledge. The neurologic signs in our case were probably caused by the WHS-related vacuolar lesions and are consistent with those of reported WHS cases. Duration of illness was shorter than is typical of WHS cases, which might be related to the disseminated histiocytic sarcoma. Clinical relevance of the lateral ventricular meningioma was not evident because the ventricular mass was localized and not invasive.
  • Hiroshi Ohta, Yu Tamura, Nozomu Yokoyama, Noriyuki Nagata, Tatsuyuki Osuga, Noboru Sasaki, Yumiko Kagawa, Keitaro Morishita, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 82 10 1445 - 1449 2020年10月20日 
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are speculated to be a breed-specific inflammatory bowel disease (IBD). Leucine-rich alpha-2 glycoprotein (LRG) has been identified as a novel biomarker of human IBD. The aim of this study was to examine LRG gene expression in the polypoid lesions of ICRPs. Polypoid lesion specimens were collected from 24 MDs with ICRPs. Nonpolypoid colonic mucosa was collected from 18 MDs with ICRPs and 10 controls. The gene expression of LRG, interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and IL-22 was examined. The expression of LRG gene was significantly increased in the polypoid lesions of ICRPs and correlated with that of the four cytokines. In conclusion, the LRG gene was expressed within the polypoid lesions of ICRPs and might be associated with local cytokine expression.
  • 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 2020年07月31日 
    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.
  • 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 2020年07月 
    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.
  • Noriyuki Nagata, Hiroshi Ohta, Arisa Yamada, Yong Bin Teoh, Osamu Ichii, Keitaro Morishita, Noboru Sasaki, Mitsuyoshi Takiguchi
    American journal of veterinary research 81 7 572 - 580 2020年07月 [査読有り][通常論文]
     
    OBJECTIVE: To investigate the activities of gelatinases (matrix metalloproteinase [MMP]-2 and MMP-9) and serine proteases in the colorectal mucosa of Miniature Dachshunds (MDs) with inflammatory colorectal polyps (ICRPs). ANIMALS: 15 MDs with ICRPs and 5 dogs with non-ICRP-related large bowel diarrhea (controls). PROCEDURES: Zymographic methods were used to evaluate the activities of MMP-2, MMP-9, latent forms of MMP-2 and MMP-9 (pro-MMP-2 and pro-MMP-9), and serine proteases in inflamed and noninflamed tissue samples from MDs with ICRPs and in noninflamed tissue samples from control dogs. The associations of serine protease activities with MMP-2 or MMP-9 activity were also analyzed. RESULTS: Activities of pro-MMP-2 and pro-MMP-9 were detected in most tissue samples, regardless of the tissue type, whereas activities of MMP-2 and MMP-9 were not detected in control tissue samples. In the inflamed tissue samples from MDs with ICRPs, the activities of MMP-2, pro-MMP-9, and MMP-9 were significantly higher than those in the noninflamed tissue samples from those dogs. Serine protease activities were significantly higher in the inflamed and noninflamed tissue samples from MDs with ICRP, compared with findings for control tissue samples. A weak correlation was detected between serine protease activities and MMP-9 activity. CONCLUSIONS AND CLINICAL RELEVANCE: Study results suggested that gelatinase and serine protease activities are upregulated in the colorectal mucosa of MDs with ICRPs, possibly contributing to the pathogenesis of this disease through the functions of these enzymes in degradation of extracellular matrix and promotion of inflammatory cell migration and inflammatory responses.
  • Hiroshi Ohta, Jumpei Yamazaki, Jaroslav Jelinek, Teita Ishizaki, Yumiko Kagawa, Nozomu Yokoyama, Noriyuki Nagata, Noboru Sasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 82 5 632 - 638 2020年05月20日 [査読有り][通常論文]
     
    DNA methylation is the covalent modification of methyl groups to DNA mostly at CpG dinucleotides and one of the most studied epigenetic mechanisms that leads to gene expression variability without affecting the DNA sequence. Genome-wide analysis of DNA methylation identified the signatures that could define subtypes of human lymphoma patients. The objective of this study was to conduct the genome-wide analysis of DNA methylation in dogs with gastrointestinal lymphoma (GIL). Genomic DNA was extracted from endoscopic biopsies from 10 dogs with GIL. We performed Digital Restriction Enzyme Assay of DNA Methylation (DREAM) for genome-wide DNA methylation analysis that could provide highly quantitative information on DNA methylation levels of CpG sites across the dog genome. We successfully obtained data of quantitative DNA methylation level for 148,601-162,364 CpG sites per GIL sample. Next, we analyzed 83,132 CpG sites to dissect the differences in DNA methylation between GIL and normal peripheral blood mononuclear cells (PBMCs). We found 383-3,054 CpG sites that were hypermethylated in GIL cases compared to PBMCs. Interestingly, 773 CpG sites including promoter regions of 61 genes were identified to be commonly hypermethylated in more than half of the cases, suggesting conserved DNA methylation patterns that are abnormal in GIL. This study revealed that there was a large number of hypermethylated sites that are common in most of canine GIL. These abnormal DNA methylation could be involved in tumorigenesis of the canine GIL.
  • Noriyuki Nagata, Hiroshi Ohta, Nozomu Yokoyama, Yong Bin Teoh, Khoirun Nisa, Noboru Sasaki, Tatsuyuki Osuga, Keitaro Morishita, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 34 2 659 - 668 2020年03月 [査読有り][通常論文]
     
    BACKGROUND: In dogs with protein-losing enteropathy (PLE), data on the clinical characteristics of food-responsive PLE (FR-PLE) remain scarce. OBJECTIVE: To determine the clinical characteristics of FR-PLE in dogs responsive to ultralow-fat diet (ULFD) management. ANIMALS: Thirty-three dogs diagnosed with PLE based on standard diagnostic criteria. METHODS: Retrospective review of medical records. Clinical findings were compared between dogs with FR-PLE (FR-PLE group) and those with immunosuppressant-responsive PLE (IR-PLE) or nonresponsive PLE (NR-PLE) (IR/NR-PLE group). The area under the curve (AUC) of a receiver operating characteristic curve was used to evaluate the ability of factors to differentiate the FR-PLE and IR/NR-PLE groups. Survival time was compared between the FR-PLE and IR/NR-PLE groups. RESULTS: Twenty-three dogs responded to ULFD management and were diagnosed with FR-PLE. The canine chronic enteropathy clinical activity index (CCECAI) was significantly lower in the FR-PLE group than in the IR/NR-PLE group (P < .001). The AUC of CCECAI for differentiating the FR-PLE group was 0.935 (95% confidence interval [CI], 0.845-1.000) with an optimal cutoff value of 8 (sensitivity, 0.826; specificity, 0.889). Survival times were significantly longer in the FR-PLE group (median, not reached) than in the IR/NR-PLE group (median, 432 days; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs that respond to ULFD management and are diagnosed with FR-PLE are expected to have a favorable prognosis. Clinical scores, specifically the CCECAI, could be useful for differentiating FR-PLE from IR-PLE or NR-PLE.
  • Jean-Michel Escoffre, Baudouin Denis de Senneville, Noboru Sasaki, Marc Derieppe
    Frontiers in pharmacology 11 954 - 954 2020年
  • Rommaneeya Leela-Arporn, Hiroshi Ohta, Genya Shimbo, Kiwamu Hanazono, Tatsuyuki Osuga, Keitaro Morishita, Noboru Sasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 12 1697 - 1704 2019年12月18日 [査読有り][通常論文]
     
    Thus far, there are few computed tomography (CT) characteristics that can distinguish benign and malignant etiologies. The criteria are complex, subjective, and difficult to use in clinical applications due to the high level of experience needed. This study aimed to identify practical CT variables and their clinical relevance for broadly classifying histopathological diagnoses as benign or malignant. In this prospective study, all dogs with liver nodules or masses that underwent CT examination and subsequent histopathological diagnosis were included. Signalments, CT findings and histopathological diagnoses were recorded. Seventy liver nodules or masses in 57 dogs were diagnosed, comprising 18 benign and 52 malignant lesions. Twenty-three qualitative and quantitative CT variables were evaluated using univariate and stepwise multivariate analyses, respectively. Two variables, namely, the postcontrast enhancement pattern of the lesion in the delayed phase (heterogeneous; odds ratio (OR): 14.7, 95% confidence interval (CI): 0.82-262.03, P=0.0429) and the maximal transverse diameter of the lesion (>4.5 cm; OR: 33.3, 95% CI: 2.29-484.18, P=0.0006), were significantly related to the differentiation of benign from malignant liver lesions, with an area under the curve of 0.8910, representing an accuracy of 88.6%. These findings indicate that features from triple-phase CT can provide information for distinguishing pathological varieties of focal liver lesions and for clinical decision making. Evaluations of the maximal transverse diameter and postcontrast enhancement pattern of the lesion included simple CT features for predicting liver malignancy with high accuracy in clinical settings.
  • Masahiro Tamura, Hiroshi Ohta, Genya Shimbo, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Yumiko Kagawa, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 33 5 2067 - 2074 2019年09月 [査読有り][通常論文]
     
    BACKGROUND: Two-dimensional shear wave elastography (2D-SWE) can noninvasively evaluate hepatic elastic modulus as shear wave velocity (SWV). Additionally, it may predict the presence of clinical relevant hepatic fibrosis (≥F2) in dogs with hepatic disease. OBJECTIVES: To investigate whether SWV measured by 2D-SWE can differentiate between dogs with (≥F2) and without (F0-1) clinically relevant hepatic fibrosis. ANIMALS: Twenty-eight client-owned dogs with hepatic disease and 8 normal healthy Beagle dogs were enrolled. METHODS: In this cross-sectional prospective study, SWVs were measured using 2D-SWE in all dogs. Hepatic fibrosis stages and necroinflammatory activity grades were histopathologically evaluated using a histological scoring scheme that was adapted from the Ishak schema used in human medicine. RESULTS: Median SWVs were significantly higher in dogs with clinically relevant hepatic fibrosis (2.04 m/s; range, 1.81-2.26 m/s) than in healthy dogs (1.51 m/s; range, 1.44-1.66 m/s; P = .007), and dogs without clinically relevant hepatic fibrosis (1.56 m/s; range, 1.37-1.67 m/s; P < .001). However, no significant difference was found in the SWVs between dogs without clinically relevant hepatic fibrosis and healthy dogs (P = .99). Furthermore, median SWVs were not significantly different among dogs with necroinflammatory activity, those without necroinflammatory activity, and healthy dogs (Kruskal-Wallis test, P = .12). CONCLUSIONS AND CLINICAL IMPORTANCE: The 2D-SWE may be useful for predicting the presence of hepatic fibrosis in dogs with hepatic disease.
  • Masahiro Tamura, Kensuke Nakamura, Tatsuyuki Osuga, Genya Shimbo, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 8 1104 - 1108 2019年08月09日 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography (CEUS) is useful to distinguish benign and malignant focal liver lesions in dogs. Cholangiocellular adenoma is an extremely rare benign tumor in dogs and has not been examined using CEUS with Sonazoid. The aim of this study was to describe findings of CEUS with Sonazoid in three dogs with cholangiocellular adenoma. All three dogs showed contrast defects in the Kupffer phase and these findings mimicked malignant neoplasia during the Kupffer phase. Moreover, all dogs showed early washout and hypoechoic lesions relative to the surrounding normal liver parenchyma in the portal phase. To our knowledge, this is the first study to report that CEUS findings of cholangiocellular adenoma with Sonazoid mimicked malignancy in three dogs.
  • Khoirun Nisa, Hiroshi Ohta, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Yumiko Kagawa, Mitsuyoshi Takiguchi
    JAPANESE JOURNAL OF VETERINARY RESEARCH 67 3 221 - 227 2019年08月 [査読有り][通常論文]
     
    Ultra low fat diet (ULFD) has shown a good therapeutic effect in dogs with intestinal lymphangiectasia secondary to CE (IL-CE). As we hypothesized that the mechanism of ULFD may involve the resolution of immunological impairment in IL-CE dogs, our study aimed to investigate the effect of ULFD on the circulating regulatory T cell (Treg) of IL-CE dogs. Treg frequency of pre- and post-ULFD blood samples from dogs with IL-CE (n = 3) were measured using flow cytometry. Treg frequency in IL-CE group before ULFD treatment showed lower tendency when compared to healthy control (mean +/- SD; 2.0 +/- 1.6% and 4.3 +/- 1.4%, respectively), and showed increased tendency after ULFD (mean +/- SD; 4.5 +/- 3.5%). The results suggested that ULFD might restore circulating Treg frequency of IL-CE dogs.
  • Angkhana Dermlim, Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Khoirun Nisa, Kazuyoshi Sasaoka, Rommaneeya Leela-Arporn, Noriyuki Nagata, Masahiro Tamura, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 7 949 - 957 2019年07月11日 [査読有り][通常論文]
     
    The purpose of this study was to evaluate the cardiac acute volume loading effect on left atrial (LA) strain and strain rate (SR) parameters derived from two-dimensional speckle tracking echocardiography (2D-STE) in healthy dogs. Six healthy beagles were anesthetized and subjected to increase cardiac preload by intravenous infusion with lactated Ringer solution at 150 ml/kg/hr for 90 min. A Swan-Ganz catheter was placed to directly measure the mean pulmonary capillary wedge pressure (PCWP). Echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 min after acute volume loading began. Apical 4-chamber images focused on the LA were digitally recorded for later strain and SR analysis via 2D-STE. Acute volume loading significantly increased from baseline during LA strain and SR as assessed by the speckle tracking-based technique during reservoir and conduit function at 15 to 90 min after volume load began, and strain indices representing booster pump function were enhanced at 45 to 90 min. In addition, acute volume loading resulted in a significantly greater PCWP after fluid infusion. On multiple regression analysis, quadratic regression analysis was a better fit for the relationship between PCWP and all LA functional indices. Our findings indicated that LA function analyzed by strain and SR was enhanced during cardiac acute volume loading in healthy dogs. The change in strain and SR during acute volume loading should be interpreted with caution during the diagnosis of heart diseases related to volume overload.
  • Rommaneeya Leela-Arporn, Hiroshi Ohta, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Khoirun Nisa, Tatsuyuki Osuga, Keitaro Morishita, Noboru Sasaki, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 33 4 1653 - 1659 2019年07月 [査読有り][通常論文]
     
    BACKGROUND: Metabolomic analysis using blood samples has been suggested to be useful for the early detection of cancer. Among metabolites, plasma-free amino acid (PFAA) profiles are potential diagnostic biomarkers for several diseases including cancer. However, the relationship between PFAA concentrations and liver tumors in dogs remains unknown. OBJECTIVE: To determine the characteristics of PFAA profiles of dogs with hepatocellular carcinoma (HCC) and correlated clinical features. ANIMALS: Thirty-four client-owned dogs diagnosed with HCC (n = 26) and benign liver diseases (n = 8) and 11 age-matched healthy dogs. METHODS: Prospective study using heparinized blood samples from fasted dogs. Plasma was deproteinized, and the concentrations of 21 amino acids were measured using an automated high-performance liquid chromatography amino acid analyzer. RESULTS: Plasma glutamic acid concentrations were significantly different among groups (P < .0024 after Bonferroni correction). Compared to healthy dogs, dogs with HCC and benign liver diseases had significantly higher concentrations of glutamic acid by post hoc analysis. However, no significant difference in the PFAA profiles of HCC and benign liver diseases were detected. In addition, preoperative and postoperative PFAA profiles of dogs with HCC were not significantly different. CONCLUSIONS AND CLINICAL IMPORTANCE: Increased glutamic acid concentrations might play a role in the development or be a consequence of liver tumor formation. However, PFAA profiles of HCC could not be differentiated from those of benign lesions. In addition, glutamic acid concentrations did not change after surgical resection. These results indicate that PFAA profiles may not be useful biomarkers for detecting HCC in dogs.
  • Yu Tamura, Hiroshi Ohta, Yumiko Kagawa, Tatsuyuki Osuga, Keitaro Morishita, Noboru Sasaki, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 33 4 1602 - 1607 2019年07月 [査読有り][通常論文]
     
    BACKGROUND: Lymphocytic-plasmacytic enteritis is the common form of idiopathic inflammatory bowel disease (IBD) in dogs. In human IBD, disturbances of amino acid metabolism have been demonstrated to be involved in the pathophysiology of IBD. Therefore, plasma amino acid profile might represent a novel marker of human IBD. OBJECTIVES: To determine the plasma amino acid profiles of dogs with IBD and its usefulness as a novel marker of IBD in dogs. ANIMALS: Fasting blood plasma was obtained from 10 dogs with IBD and 12 healthy dogs. METHODS: All IBD dogs were prospectively included in this study, and heparinized blood samples were collected. The plasma concentrations of 21 amino acids were determined using the ninhydrin method. The relationships among the plasma amino acid concentrations and plasma C-reactive protein (CRP) concentration, canine chronic enteropathy clinical activity index (CCECAI), and overall World Small Animal Veterinary Association (WSAVA) score were investigated. RESULTS: Median concentration (nmol/mL) of methionine [46.2; range, 30.0-59.3], proline [119.4; range, 76.7-189.2], serine [115.1; range, 61.4-155.9], and tryptophan [17.4; range, 11.9-56.3]) were significantly lower than in control dogs [62.6; range, 51.0-83.6, 199.1; range, 132.5-376.7, 164.3; range, 124.7-222.9, and 68.3; range, 35.7-94.8, respectively]. A negative correlation was identified between the plasma serine concentration and CCECAI (r s = -.67, P = .03), but there were no correlations between plasma amino acid concentrations and CRP concentration or overall WSAVA score. CONCLUSIONS AND CLINICAL IMPORTANCE: Plasma serine concentration might represent a novel maker of IBD in dogs.
  • Leela-Arporn R, Ohta H, Nagata N, Sasaoka K, Tamura M, Dermlim A, Nisa K, Morishita K, Sasaki N, Nakamura K, Takagi S, Hosoya K, Takiguchi M
    Veterinary journal (London, England : 1997) 248 74 - 78 2019年06月 [査読有り][通常論文]
  • Morita, T, Nakamura, K, Osuga, T, Morishita, K, Sasaki, N, Ohta, H. Takiguchi, M
    Journal of Veterinary Cardiology 23 1 1 - 14 2019年06月 [査読有り][通常論文]
  • Dermlim, A, Nakamura, K, Morita, T, Osuga, T, Nisa, K, Sasaoka, K, Leela-arporn, R, Sasaki, N, Ohta, H, Takiguchi, M
    Journal of Veterinary Cardiology 23 1 69 - 80 2019年06月 [査読有り][通常論文]
  • Rommaneeya Leela-Arporn, Hiroshi Ohta, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Khoirun Nisa, Keitaro Morishita, Noboru Sasaki, Kensuke Nakamura, Satoshi Takagi, Kenji Hosoya, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 5 723 - 729 2019年05月31日 [査読有り][通常論文]
     
    A definitive diagnosis of focal liver lesions (FLLs) requires invasive procedures for histopathologic examination. Thus, a simpler noninvasive diagnostic method, such as conventional ultrasonography combined with clinical data, is needed for the prediction of liver malignancy. The objective of this study was to examine the diagnostic accuracy of clinical data and ultrasonographic (US) features to differentiate benign and malignant liver lesions. Medical records and US images from dogs with FLLs that underwent abdominal US and histopathologic examinations following surgery or liver biopsy were retrospectively reviewed. Clinical data, including signalment, clinical signs and laboratory findings, and the US features of liver lesions that could act as predictive factors were assessed using univariate and multivariate analyses to evaluate the associations between predictive factors and liver malignancy. Based on the histopathologic results, 55 dogs with malignant lesions and 28 dogs with benign lesions were included in the study. The results of univariate analysis showed that several US features and platelet count were significantly associated with liver malignancy. Multivariate analysis revealed that the platelet count (thrombocytosis; odds ratio [OR]: 4.13, 95% confidence intervals [CI]: 1.81-9.41), lesion size (4.1 cm or greater; OR: 23.83, 95% CI: 3.74-151.95) and echotexture of FLLs (heterogenous; OR: 8.44; 95% CI: 1.37-51.91) were independent predictors for differentiating benign and malignant liver lesions, suggesting that a combination of clinical data and US findings of FLLs could predict liver malignancy in dogs.
  • Masahiro Tamura, Hiroshi Ohta, Khoirun Nisa, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Mitsuyoshi Takiguchi
    American journal of veterinary research 80 4 378 - 384 2019年04月 [査読有り][通常論文]
     
    OBJECTIVE: To assess liver and spleen stiffness in healthy dogs by use of a novel 2-D shear wave elastography (SWE) technique and to investigate the repeatability and reproducibility of the technique. ANIMALS: 8 healthy adult Beagles. PROCEDURES: 2-D SWE was performed on each dog to assess liver and spleen stiffness. Repeatability (intraday variability) and reproducibility (interday variability) of 2-D SWE were investigated. For all 8 dogs, 2-D SWE was performed 3 times in 1 day (4-hour intervals) and on 3 separate days (1-week interval). Data were expressed as mean ± SD values for shear wave velocity and the Young modulus in the liver and spleen. Intraday and interday coefficients of variation were assessed for all variables. RESULTS: Mean ± SD shear wave velocity obtained for the liver and spleen was 1.51 ± 0.08 m/s and 2.18 ± 0.27 m/s, respectively. Mean value for the Young modulus obtained for the liver and spleen was 6.93 ± 0.79 kPa and 14.66 ± 3.79 kPa, respectively. Elasticity values were significantly higher for the spleen than for the liver. Intraday and interday coefficients of variation for all variables were < 25% (range, 3.90% to 20.70%). CONCLUSIONS AND CLINICAL RELEVANCE: 2-D SWE was a feasible technique for assessing liver and spleen stiffness of healthy dogs. Future studies on the application of 2-D SWE for dogs with chronic hepatitis, cirrhosis, and portal hypertension are needed to evaluate the clinical applicability of 2-D SWE.
  • Masahiro Tamura, Hiroshi Ohta, Khoirun Nisa, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Mitsuyoshi Takiguchi
    Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association 60 2 192 - 200 2019年03月 [査読有り][通常論文]
     
    Extrahepatic-congenital portosystemic shunt is a vascular anomaly that connects the portal vein to the systemic circulation and leads to a change in hepatic microvascular perfusion. However, an assessment of hepatic microvascular perfusion is limited by conventional diagnostic modalities. The aim of this prospective, exploratory study was to assess hepatic microvascular perfusion in dogs with extrahepatic-congenital portosystemic shunt using contrast-enhanced ultrasonography (CEUS) using perfluorobutane (Sonazoid® ). A total of 17 dogs were included, eight healthy dogs and nine with extrahepatic-congenital portosystemic shunt. The time-to-peak (TTP), rising time (RT), and rising rate (RR) in the hepatic artery, portal vein, and hepatic parenchyma, as well as the portal vein-to-hepatic parenchyma transit time (ΔHP-PV) measured from time-intensity curve on CEUS were compared between healthy and extrahepatic-congenital portosystemic shunt dogs. The RT of the hepatic artery in extrahepatic-congenital portosystemic shunt dogs was significantly earlier than in healthy dogs (P = 0.0153). The TTP and RT of the hepatic parenchyma were significantly earlier in extrahepatic-congenital portosystemic shunt dogs than in healthy dogs (P = 0.0018 and P = 0.0024, respectively). ΔHP-PV was significantly shorter in extrahepatic-congenital portosystemic shunt dogs than in healthy dogs (P = 0.0018). CEUS effectively revealed changes in hepatic microvascular perfusion including hepatic artery, portal vein, and hepatic parenchyma simultaneously in extrahepatic-congenital portosystemic shunt dogs. Rapid hepatic artery and hepatic parenchyma enhancements may reflect a compensatory increase in hepatic artery blood flow (arterialization) caused by a decrease in portal vein blood flow and may be used as an additional diagnostic test to distinguish extrahepatic-congenital portosystemic shunt dogs from healthy dogs.
  • Khoirun Nisa, Sue Yee Lim, Masayoshi Shinohara, Tatsuyuki Osuga, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 33 2 559 - 568 2019年03月 [査読有り][通常論文]
     
    BACKGROUND: Contrast-enhanced ultrasonography (CEUS) can be used to evaluate intestinal perfusion in healthy dogs. It is helpful for diagnosing and monitoring inflammatory bowel disease in humans and could be useful for dogs with chronic intestinal diseases. OBJECTIVES: To examine duodenal perfusion in dogs with chronic inflammatory enteropathy (CIE) and intestinal lymphoma. ANIMALS: Client-owned dogs with CIE (n = 26) or intestinal lymphoma (n = 7) and dogs with gastrointestinal signs but histopathologically normal duodenum (controls, n = 14). METHODS: In this cross-sectional study, dogs with CIE were classified into remission (n = 16) and symptomatic (n = 10) groups based on clinical scores determined at the time of CEUS. The duodenum was scanned after IV injection of Sonazoid® (0.01 mL/kg). CEUS-derived perfusion parameters, including time-to-peak, peak intensity (PI), area under the curve (AUC), and wash-in and wash-out rates were evaluated. RESULTS: The PI was significantly higher in the symptomatic CIE group (median (range); 105.4 (89.3-128.8) MPV) than in the control group (89.9 (68.5-112.2) MPV). The AUC was significantly higher in the symptomatic CIE group (4847.9 (3824.3-8462.8) MPV.sec) than in the control (3448.9 (1559.5-4736.9) MPV.sec) and remission CIE (3862.3 (2094.5-6899.0) MPV.sec) groups. The PI and clinical score were positively correlated in the CIE group. No significant differences in perfusion parameters were detected between the lymphoma and CIE groups or the lymphoma and control groups. CONCLUSIONS AND CLINICAL IMPORTANCE: The PI and AUC can detect duodenal inflammation and hence are potentially useful for excluding a diagnosis of CIE.
  • Noboru Sasaki, Nobuki Kudo, Hiroshi Ohta, Mitsuyoshi Takiguchi
    2019 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS) 1308 - 1310 2019年 
    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.
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Nozomu Yokoyama, Keitaro Morishita, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    American journal of veterinary research 80 1 51 - 60 2019年01月 [査読有り][通常論文]
     
    OBJECTIVE To determine the relationship between acute volume overload and echocardiographic indices of right ventricular (RV) function and dyssynchrony in healthy dogs. ANIMALS 7 healthy Beagles. PROCEDURES Right heart catheterization and echocardiography were performed in 7 healthy anesthetized Beagles at baseline and after induction of volume overload. Volume overload was induced by IV infusion of lactated Ringer solution (150 mL/kg/h for 90 minutes). Echocardiographic indices of RV function, including peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, RV Tei index, RV longitudinal strain (RVLS), and systolic RV longitudinal strain rate (RVLSR), were obtained by use of speckle tracking echocardiography (STE). In addition, SD of the systolic shortening time of the right ventricle for the 6 segments (RV-SD6) was determined with STE. RESULTS Volume overload significantly increased the RV end-diastolic pressure, compared with the baseline value. Echocardiographic indices of RV function, except for septal RVLSR, were significantly enhanced by volume overload. In contrast, RV-SD6 did not change with volume overload. Although echocardiographic indices of RV function, except for septal RVLSR, were correlated with RV end-diastolic pressure, RV-SD6 was not correlated. CONCLUSIONS AND CLINICAL RELEVANCE Echocardiographic indices of RV function, including RVLS and RVLSR, were affected by acute short-term volume overload. Therefore, results for assessment of RV function by use of STE in dogs with clinical conditions associated with right-sided chronic volume overload, such as tricuspid and pulmonic regurgitation, should be interpreted with caution.
  • Hiroshi Ohta, Kazuki Kojima, Nozomu Yokoyama, Noboru Sasaki, Yumiko Kagawa, Kiwamu Hanazono, Tomohito Ishizuka, Keitaro Morishita, Kensuke Nakamura, Satoshi Takagi, Mitsuyoshi Takiguchi
    Canadian journal of veterinary research = Revue canadienne de recherche veterinaire 82 4 278 - 286 2018年10月 [査読有り][通常論文]
     
    The objective of this study was to examine the effects of immunosuppressive prednisolone therapy on pancreatic tissue and the concentration of serum canine pancreatic lipase immunoreactivity (cPLI) in healthy dogs. Six healthy beagle dogs were subcutaneously administered an immunosuppressive dose of prednisolone [4 mg/kg body weight (BW)] once daily for either 2 or 3 weeks. Serum cPLI concentration was measured before and after treatment. Ultrasonographic examination of the pancreas and laparoscopic biopsy and histopathological examination of the right pancreatic lobe and the liver were also conducted before and after treatment. The expression of pancreatic lipase messenger ribonucleic acid (mRNA) in the pancreas and liver was examined by polymerase chain reaction (PCR). Although the serum cPLI concentration was significantly higher on day 14 and on the day of the second laparoscopy than before treatment, it was classified as normal (≤ 200 μg/L) in 5 dogs and as abnormal (≥ 400 μg/L) in only 1 dog. None of the 6 dogs showed clinical signs of pancreatitis during the study period. After treatment, ultrasonographic examination of the pancreas showed no changes except for a hypoechoic pancreas in 1 dog. Histopathological examination of the right pancreatic lobe in all dogs showed no evidence of pancreatitis after treatment. Pancreatic lipase mRNA expression was detected in the pancreas, but not in the liver, before and after treatment. The administration of 4 mg/kg BW per day of prednisolone for 2 or 3 weeks increased the serum cPLI concentration without clinical signs of pancreatitis, although an abnormal cPLI concentration (≥ 400 μg/L) was observed in only 1 dog. No ultrasonographic or histological evidence of pancreatitis was observed in any of the dogs.
  • Khoirun Nisa, Sue Yee Lim, Tatsuyuki Osuga, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 80 3 453 - 459 2018年03月24日 [査読有り][通常論文]
     
    Quantitative contrast-enhanced ultrasonography (CEUS) enables non-invasive and objective evaluation of intestinal perfusion by quantifying the intensity of enhancement on the intestine after microbubble contrast administration. During CEUS scanning, sedation is sometimes necessary to maintain animal cooperation. Nevertheless, the effect of sedative administration on the canine intestinal CEUS is unknown. This study aimed to investigate the effect of sedation with a combination of butorphanol and midazolam on the duodenal CEUS-derived perfusion parameters of healthy dogs. For this purpose, duodenum was imaged following contrast administration (Sonazoid®, 0.01 ml/kg) in six healthy beagles before and after intravenous injection of a combination of butorphanol (0.2 mg/kg) and midazolam (0.1 mg/kg). Furthermore, hemodynamic parameters including blood pressure and heart rate were recorded during the procedure. Five CEUS derived perfusion parameters including time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), wash-in and wash-out rates (WiR and WoR, respectively) before and after sedation were statistically compared. The result showed that no significant change was detected in any of perfusion parameters. Systolic and mean arterial pressures significantly reduced after sedative administration, but diastolic arterial pressure and heart rate did not significantly change. Moreover, no significant partial correlation was observed between perfusion parameters and hemodynamic parameters. Thus, we concluded that the combination did not cause significant influence in duodenal CEUS perfusion parameters and could be a good option for sedation prior to duodenal CEUS in debilitated dogs.
  • K. Sasaoka, K. Nakamura, T. Osuga, T. Morita, N. Yokoyama, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 32 1 314 - 323 2018年01月01日 [査読有り][通常論文]
     
    Background: Transcranial Doppler ultrasound examination (TCD) is a rapid, noninvasive technique used to evaluate cerebral blood flow and is useful for the detection of intracranial hypertension in humans. However, the clinical usefulness of TCD in diagnosing intracranial hypertension has not been demonstrated for intracranial diseases in dogs. Objectives: To determine the association between the TCD variables and intracranial hypertension in dogs with intracranial diseases. Animals: Fifty client-owned dogs with neurologic signs. Methods: Cross-sectional study. All dogs underwent TCD of the basilar artery under isoflurane anesthesia after magnetic resonance imaging (MRI). Dogs were classified into 3 groups based on MRI findings: no structural diseases (group I), structural disease without MRI evidence of intracranial hypertension (group II), and structural disease with MRI evidence of intracranial hypertension (group III). The TCD vascular resistance variables (resistive index [RI], pulsatility index [PI], and the ratio of systolic to diastolic mean velocity [Sm/Dm]) were measured. Results: Fifteen, 22, and 13 dogs were classified into groups I, II, and III, respectively. Dogs in group III had significantly higher Sm/Dm (median, 1.78 range, 1.44–2.58) than those in group I (median, 1.63 range, 1.43–1.75) and group II (median, 1.62 range, 1.27–2.10). No significant differences in RI and PI were identified among groups. Conclusions and Clinical Importance: Our findings suggest that increased Sm/Dm is associated with MRI findings of suspected intracranial hypertension in dogs with intracranial diseases and that TCD could be a useful tool to help to diagnose intracranial hypertension.
  • Osamu Ichii, Hiroshi Ohta, Taro Horino, Teppei Nakamura, Marina Hosotani, Tatsuya Mizoguchi, Keitaro Morishita, Kensuke Nakamura, Noboru Sasaki, Mitsuyoshi Takiguchi, Ryo Sato, Kazuhisa Oyamada, Yaser Hosny Ali Elewa, Yasuhiro Kon
    Frontiers in veterinary science 5 289 - 289 2018年 [査読有り][通常論文]
     
    Increased incidence of kidney disease (KD) is a common concern in human and companion animals. Cats, in particular, are highly susceptible to KD. Novel KD biomarkers would help to address these problems. Therefore, we are focusing on microRNA, a highly conserved nucleic acid, as a KD biomarker for various animals. We previously reported that altered levels of urinary exosome (UExo)-derived microRNAs indicate renal pathologies in dogs. This study comprehensively examined UExo-derived microRNAs, which reflected the KD status in cats. The examined cats were divided into two groups: normal renal function (NR) and KD. Based on our previous data in dogs and cats, as well as the present data on UExo-derived microRNAs in cats by next-generation sequencing, let-7b, let-7f, miR-10a, miR-10b, miR-21a, miR-22, miR-26a, miR-27b, miR-146a, miR-181a, miR-191, and miR-486a were identified as biomarker candidates. In summary, the levels of UExo-derived let-7b, miR-22, and miR-26a significantly decreased in cats with KD from the early stages of the disease. UExo-derived miRNA levels normalized to urinary creatinine or total RNA of miR-21a was significantly higher in the KD group. Importantly, the ratio of UExo-derived miR-21a to let-7b showed a significant and strongest correlation with serum creatinine (ρ = 0.751), blood urea nitrogen (ρ = 0.754), and urinary creatinine (ρ = -0.421) among all examined indices. Further, the ratio of miR-181a to let-7b or miR-10b significantly correlated with the progression of renal dysfunction in the KD group. Thus, we identified that UExo-derived microRNAs in cats, and their raw and normalized levels could indicate altered renal function.
  • 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年11月 [査読有り][通常論文]
     
    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 nonmuscle 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 mu m 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.
  • Khoirun Nisa, Sue Yee Lim, Masayoshi Shinohara, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Nozomu Yokoyama, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 79 9 1585 - 1590 2017年09月29日 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography (CEUS) with microbubbles as a contrast agent allows the visualization and quantification of tissue perfusion. The assessment of canine intestinal perfusion by quantitative CEUS may provide valuable information for diagnosing and monitoring chronic intestinal disorders. This study aimed to assess the repeatability (intraday variability) and reproducibility (interday variability) of quantitative duodenal CEUS in healthy dogs. Six healthy beagles underwent CEUS three times within one day (4-hr intervals) and on two different days (1-week interval). All dogs were sedated with a combination of butorphanol (0.2 mg/kg) and midazolam (0.1 mg/kg) prior to CEUS. The contrast agent (Sonazoid®) was administered using the intravenous bolus method (0.01 ml/kg) for imaging of the duodenum. Time-intensity curves (TIC) were created by drawing multiple regions of interest (ROIs) in the duodenal mucosa, and perfusion parameters, including the time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), and wash-in and wash-out rates (WiR and WoR, respectively), were generated. Intraday and interday coefficients of variation (CVs) for TTP, PI, AUC, WiR and WoR were <25% (range, 2.27-23.41%), which indicated that CEUS was feasible for assessing duodenal perfusion in healthy sedated dogs. A further study of CEUS in dogs with chronic intestinal disorders is necessary to evaluate its clinical applicability.
  • T. Morita, K. Nakamura, T. Osuga, N. Yokoyama, N. Khoirun, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY CARDIOLOGY 19 4 351 - 362 2017年08月 [査読有り][通常論文]
     
    Introduction: To assess the repeatability and characteristics of echocarCanine; diographic indices of the right ventricular (RV) function derived from speckle-track Cardiac; ing echocardiography. Right ventricular Animals: Fourteen laboratory Beagles and 103 privately owned dogs without cardifunction; ac disease were involved in this study. Dyssynchrony; Materials and methods: Right ventricular longitudinal strain, strain rate, and a Tei index strain-related index for assessing RV dyssynchrony derived from speckle-tracking echocardiography were obtained by two different observers using five Beagles. Within-day, between-day, and interobserver coefficients of variation and the intraclass correlation coefficient of speckle-tracking echocardiography indices were determined. Both speckle-tracking echocardiography and conventional indices of RV function, including the peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, and the Tel index, were obtained from 14 Beagles and 103 privately owned dogs. Relationships between echocardiographic indices and the body weight, heart rate, age, and sex were estimated by regression analysis. Results: Speckle-tracking echocardiographic indices showed good within-day repeatability, between-day and interobserver repeatability were moderate to good. In large dogs, RV longitudinal strain, strain rate, and fractional area change were significantly decreased, while the index of RV dyssynchrony, systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, and the Tei index were increased. All speckle-tracking and conventional echocardiographic indices were correlated with the body weight. Discussion and conclusions: The speckle-tracking echocardiography indices were highly repeatable and body weight affected speckle-tracking echocardiography indices in dogs. Further studies are needed to apply speckle-tracking echocardiography indices in dogs with cardiac disease. (C) 2017 Elsevier B.V. All rights reserved.
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Nozomu Yokoyama, Keitaro Morishita, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    ECHOCARDIOGRAPHY-A JOURNAL OF CARDIOVASCULAR ULTRASOUND AND ALLIED TECHNIQUES 34 7 1040 - 1049 2017年07月 [査読有り][通常論文]
     
    Background: The assessment of hemodynamic change by echocardiography is clinically useful in patients with pulmonary hypertension. Recently, mild elevation of the mean pulmonary arterial pressure (PAP) has been shown to be associated with increased mortality. However, changes in the echocardiographic indices of right ventricular (RV) function are still unknown. The objective of this study was to validate the relationship between echocardiographic indices of RV function and right heart catheterization variables under a mild RV pressure overload condition. Methods and Results: Echocardiography and right heart catheterization were performed in dog models of mild RV pressure overload induced by thromboxane A(2) analog (U46619) (n=7). The mean PAP was mildly increased (19.3 +/- 1.1mm Hg), and the cardiac index was decreased. Most echocardiographic indices of RV function were significantly impaired even under a mild RV pressure overload condition. Multivariate analysis revealed that the RV free wall longitudinal strain (RVLS), standard deviation of the time-to-peak longitudinal strain of RV six segments (RV-SD) by speckle-tracking echocardiography, and Tei index were independent echocardiographic predictors of the mean PAP (free wall RVLS, beta=-0.60, P<.001; RV-SD, beta=0.40, P=.011), pulmonary vascular resistance (free wall RVLS, beta=-0.39, P=.020; RV-SD, beta=0.47, P=.0086; Tei index, beta=0.34, P=.047), and cardiac index (Tei index, beta=-0.65, P<.001). Conclusions: Free wall RVLS, RV-SD, and Tei index are useful for assessing the hemodynamic change under a mild RV pressure overload condition.
  • H. Ohta, T. Morita, N. Yokoyama, T. Osuga, N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi
    JOURNAL OF SMALL ANIMAL PRACTICE 58 6 342 - 347 2017年06月 [査読有り][通常論文]
     
    ObjectivesIn this pilot study, serum canine pancreatic lipase immunoreactivity was measured repeatedly in dogs with various immune-mediated diseases that were treated with immunosuppressive doses of prednisolone. MethodsTen client-owned dogs with newly diagnosed immune-mediated disease that had normal canine pancreatic lipase immunoreactivity concentrations (200 mu g/l) were treated with 2 to 2.2 mg/kg prednisolone orally once daily as the initial treatment. Serum samples were obtained from each of the dogs prior to treatment and at 1- to 4-week intervals during immunosuppressive treatment. The highest canine pancreatic lipase immunoreactivity concentration detected during immunosuppressive treatment was defined as the peak canine pancreatic lipase immunoreactivity. ResultsPeak canine pancreatic lipase immunoreactivity concentrations were classified as normal in two dogs, questionable (201 to 399 mu g/l) in three dogs, and abnormal (400 mu g/l) in five dogs. Peak canine pancreatic lipase immunoreactivity concentrations were significantly higher than baseline canine pancreatic lipase immunoreactivity concentrations but there was no evidence of clinical pancreatitis. Clinical SignificanceIt remains unclear whether the five of 10 dogs with elevated canine pancreatic lipase immunoreactivity during prednisone treatment had subclinical pancreatitis or whether the abnormal results were a consequence of prednisolone administration.
  • Nozomu Yokoyama, Hiroshi Ohta, Yumiko Kagawa, Noriyuki Nagata, Khoirun Nisa, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Mitsuyoshi Takiguchi
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 188 78 - 83 2017年06月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are a possible novel form of breed-specific canine inflammatory bowel disease (IBD). In this pilot study, we investigated the effects of different Toll like receptor (TLR2, TLR4, TLR5 and TLR9) ligands on pro-inflammatory cytokines (IL-1 beta, IL-6, IL-8 and TNF-alpha) gene expression in ex vivo-cultured colorectal samples from four MDs with ICRPs and four healthy MDs. At baseline, no significant difference in the mRNA expression levels of TLRs and pro-inflammatory cytokines was observed between cases and control MDs. After 4-h incubation, the relative ratios of TNF-alpha mRNA expression in the TLR2-or TLR4-stimulated colorectal samples, and IL-1 beta mRNA expression in the TLR9-stimulated colorectal samples form cases showed higher tendency compared with healthy MDs (P < 0.05), although statistically not significant. The results of this pilot study using small number of cases indicated that reactivity against TLR2, TLR4 or TLR9 ligand in the production of pro-inflammatory cytokines might be enhanced in the colorectal mucosa of ICRPs. Further research is needed to perform the functional analysis of TLRs in the sole cell population using intestinal epithelial primary culture and the mononuclear cells isolated from colonic mucosa.
  • K. Morishita, A. Hiramoto, A. Michishita, S. Takagi, T. Osuga, S. Y. Lim, K. Nakamura, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 31 3 770 - 777 2017年05月01日 [査読有り][通常論文]
     
    Background: Perflubutane microbubbles, a second-generation ultrasound contrast agent, are phagocytized by Kupffer cells. This characteristic may be useful to differentiate diffuse hepatic diseases in dogs. Hypothesis/objectives: To determine whether the washout ratio in the hepatic vein (HV) measured by contrast-enhanced ultrasonography (CEUS) can distinguish between inflammatory and noninflammatory hepatic disorders in dogs. Animals: Forty-one client-owned dogs with hepatic disorders including 14 with hepatitis, 7 with primary hypoplasia of the portal vein (PHPV), 9 with congenital portosystemic shunt (cPSS), and 11 with other hepatopathy were enrolled. Six dogs without hepatic disease also were evaluated as healthy controls. Methods: Dogs with hepatic disorders were prospectively included. Contrast-enhanced ultrasonography of the HV was performed for 2 minutes. Washout ratio was defined as the attenuation rate from peak intensity to the intensity at the end of the CEUS study. Results: Washout ratio in the hepatitis group (median, 18.0% range, 2.0–37.0%) was significantly lower than that of the PHPV (median, 52.2% range, 11.5–86.3%), cPSS (median, 60.0% range, 28.6–77.4%), other hepatopathy (median, 70.5% range, 26.6–88.4%), and normal (median, 78.0% range, 60.7–91.7%) groups. The area under the receiver operating characteristic curve for hepatitis was 0.960, with a 95% confidence interval (CI) of 0.853–0.990. Washout ratio ≤37.1% resulted in a sensitivity of 100% (95% CI, 78.5–100%) and specificity of 85.2% (95% CI, 67.5–94.1%) for the prediction of hepatitis. Conclusions and Clinical Importance: Washout ratio can distinguish hepatitis from the other noninflammatory disorders with high accuracy. This result might reflect impaired Kupffer cell phagocytosis in dogs with hepatitis.
  • K. Nakamura, S. Kawamoto, T. Osuga, T. Morita, N. Sasaki, K. Morishita, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 31 2 316 - 325 2017年03月01日 [査読有り][通常論文]
     
    Background: Decreased function of the left atrium (LA) is a useful prognostic indicator in dogs with myxomatous mitral valve disease (MMVD). In humans, LA strain is a novel severity indicator of mitral regurgitation, but its clinical utility in dogs has not been confirmed. Objectives: To examine whether LA strain as evaluated with speckle-tracking echocardiography is associated with MMVD stage in dogs. Animals: Fifty-two client-owned dogs with MMVD. Methods: Cross-sectional study. Dogs were classified as stage B1, B2, C, or D, according to the American College of Veterinary Internal Medicine consensus. Physical examination findings and echocardiographic variables were compared among the groups. To assess the comparative accuracy of echocardiographic variables in identifying dogs with the presence or history congestive heart failure (CHF), receiver operating characteristic curves and multivariate logistic analysis were used. Results: There were no significant differences in parameters of LA strain between B1 and B2 groups. However, LA longitudinal strain during atrial contraction (εA) (median, 19.1% interquartile range, 15.3–24.3% in B1, 19.6% 14.1–21.4% in B2, 6.2% 3.18–11.2% in C/D) and during ventricular systole (εS) (32.7% 28.9–39.2% in B1, 35.6% 31.7–41.9% in B2, 23.6% 16.9–26.1% in C/D) were significantly lower in stages C/D than in stages B1 and B2. In multivariate logistic regression analysis, εA and peak early diastolic mitral inflow velocity were identified as independent indicators of stage C/D. Conclusions and Clinical Importance: εA was the best predictor of the presence or history of CHF. Further studies are needed to determine the clinical implications of these findings for treatment decisions and prognosis determination.
  • Nozomu Yokoyama, Hiroshi Ohta, Yumiko Kagawa, Rommaneeya Leela-Arporn, Angkhana Dermlim, Khoirun Nisa, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Mitsuyoshi Takiguchii
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 3 456 - 463 2017年03月 [査読有り][通常論文]
     
    We examine the expression of tight junction and adherence junction proteins in the colorectal mucosa of miniature dachshunds (MDs) with inflammatory colorectal polyps (ICRPs). Colorectal mucosa samples were endoscopically obtained from 8 MDs with ICRPs and 8 control dogs for immunoblotting. Paraffin-embedded tissues of surgically resected inflamed lesions from another 5 MDs with ICRPs and full-thickness colorectal specimens from 5 healthy beagles were obtained for immunohistochemistry. The expression patterns of claudin-1, -2, -3, -4, -5, -7 and -8, E-cadherin and beta-catenin were analyzed in the non(-)inflamed mucosa and inflamed mucosa of ICRPs and colorectal mucosa of control dogs by immunoblotting.The localization of these proteins in the inflamed lesions was analyzed by immunohistochemistry. The expressions of each of claudin, E-cadherin and beta-catenin were not significantly different between control dogs and non inflamed colonic mucosa from MDs with ICRPs. In contrast, only E-cadherin and beta-catenin were detected in the inflamed lesions of MDs with 1CRPs. By immunohistochemistry, claudin-2, -3, -4, -5 and -7, E-cadherin and beta-catenin were expressed in the colorectal epithelium within the inflamed mucosa, but not in granulation tissue. Distributions of claudin-2, -3, -4, -5, and -7, E-cadherin and beta-catenin in the colonic epithelium were not different between MDs with ICRPs and control dogs. These results indicated that no significant alteration was detected in several tight junction or adherence junction proteins expression in the colorectal epithelium of ICRPs.
  • N. Yokoyama, H. Ohta, J. Yamazaki, Y. Kagawa, O. Ichii, N. Khoirun, T. Morita, T. Osuga, S. Y. Lim, N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi
    Journal of Comparative Pathology 156 2-3 183 - 190 2017年02月01日 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) are characterized by the formation of multiple or solitary polyps with marked neutrophil infiltration in the colorectal area, and are speculated to be a novel form of breed-specific canine idiopathic inflammatory bowel disease (IBD). In human IBD, toll-like receptor (TLR) 2 and TLR4 have been reported to be involved in the pathogenesis of the disease. The aim of this study was to evaluate the expression of TLR2 and TLR4 mRNA in the colorectal mucosa of dogs with ICRPs by in-situ hybridization using an RNAscope assay. Samples of inflamed colorectal mucosa (n = 5) and non-inflamed mucosa (n = 5) from miniature dachshunds (MDs) with ICRPs and colonic mucosa from healthy beagles (n = 5) were examined. TLR2 and TLR4 hybridization signals were localized to the colorectal epithelium, inflammatory cells and fibroblasts in the inflamed colorectal mucosa of affected dogs. The signals were significantly greater in inflamed colorectal epithelium compared with non-inflamed epithelium of MDs with ICRPs and healthy beagles (P < 0.05). These results suggest that increased expression of TLR2 and TLR4 mRNA in the inflamed colorectal mucosa results from not only inflammatory cell infiltration, but also the upregulation of TLR2 and TLR4 mRNA in the colonic epithelium.
  • Osamu Ichii, Hiroshi Ohta, Taro Horino, Teppei Nakamura, Marina Hosotani, Tatsuya Mizoguchi, Keitaro Morishita, Kensuke Nakamura, Yuki Hoshino, Satoshi Takagi, Noboru Sasaki, Mitsuyoshi Takiguchi, Ryo Sato, Kazuhisa Oyamada, Yasuhiro Kon
    SCIENTIFIC REPORTS 7 40340  2017年01月 [査読有り][通常論文]
     
    MicroRNAs act as post-transcriptional regulators, and urinary exosome (UExo)-derived microRNAs may be used as biomarkers. Herein, we screened for UExo-derived microRNAs reflecting kidney disease (KD) status in dogs. Examined dogs were divided into healthy kidney control (HC) and KD groups according to renal dysfunction. We confirmed the appearance of UExo having irregular globe-shapes in a dog by immunoblot detection of the exosome markers, TSG101 and CD9. Based on our previous data using KD model mice and the data obtained herein by next generation sequencing of UExo-derived microRNAs in dogs, miR-26a, miR-146a, miR-486, miR-21a, and miR-10a/b were selected as candidate microRNAs. In particular, UExo-derived miR-26a and miR-10a/b were significantly decreased in KD dogs, and miR-26a levels negatively correlated with deteriorated renal function compared to the other miRNAs. UExo-derived miR-21a levels corrected or not to that of internal control microRNAs in UExo, miR-26a and miR-191, significantly increased with renal dysfunction. In kidney tissues, the decrease of miR-26a and miR-10a/ b in the glomerulus and miR-10b in the tubulointerstitium negatively correlated with deteriorated renal function and histopathology. Increased miR-21a in the tubulointerstitium rather than in the glomerulus correlated with deteriorated renal histopathology. In conclusion, microRNAs reflecting the changes in renal function and histopathology in dogs were identified in this study.
  • Keitaro Morishita, Akira Hiramoto, Tatsuyuki Osuga, Sue Yee Lim, Nisa Khoirun, Noboru Sasaki, Kensuke Nakamura, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 78 12 1753 - 1758 2016年12月 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography (CEUS) of the hepatic vein can assess intrahepatic hemodynamic changes and has been studied as a noninvasive method to assess the severity of portal hypertension and hepatic fibrosis in humans. However, few reports have described its usefulness in veterinary medicine. The purpose of this study was to characterize CEUS findings of the hepatic vein in normal dogs and assess the repeatability of this method both in a conscious group (n=6) and a sedated group (n=6). Sonazoid (R) (0.01 ml/kg) was used as a contrast agent, and scanning of the hepatic vein was performed for 2 min. Time-intensity curves were generated from regions of interest in the hepatic vein. Four perfusion parameters were measured for quantitative analysis: hepatic vein arrival time (HVAT), time to peak (TTP), time to peak phase (TTPP) and wash-out ratio (WR). CEUS examinations were performed three times in each dog. The median (range) values of HVAT, TTP, TTPP and WR in the conscious group were 13.5 sec (9-22 sec), 12.5 sec (6-24 sec), 8 sec (6-13 sec) and 78.0% (60.7-91.7%), respectively. Median (range) values of HVAT, TTP, TTPP and WR in the sedated group were 12 sec (8-17 sec), 12.5 sec (9-17 sec), 9 sec (7-13 sec) and 84.1% (63.0-94.4%), respectively. The coefficients of variation of these parameters in the conscious and sedated groups were 7.6-29.7% and 11.8-14.8%, respectively.
  • Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Khoirun Nisa, Nozomu Yokoyama, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH 77 9 952 - 960 2016年09月 [査読有り][通常論文]
     
    OBJECTIVE To elucidate the relationship between acute volume overload and left atrial phasic function in healthy dogs. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized. A Swan-Ganz catheter was placed to measure mean pulmonary capillary wedge pressure (PCWP). Cardiac preload was increased by IV infusion with lactated Ringer solution at 150 mL/kg/h for 90 minutes. Transthoracic echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after volume loading began. At each echocardiographic assessment point, apical 4-chamber images were recorded and analyzed to derive time-left atrial area curves. Left atrial total (for reservoir function), passive (for conduit function), and active (for booster-pump function) fractional area changes were calculated from the curves. RESULTS Volume overload resulted in a significant increase from baseline in PCWP from 15 to 90 minutes after volume loading began. All fractional area changes at 15 to 90 minutes were significantly increased from baseline. In multiple regression analysis, quadratic regression models were better fitted to the relationships between PCWP and each of the total and active fractional area changes than were linear regression models. A linear regression model was better fitted to the relationship between PCWP and passive fractional area change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that left atrial phasic function assessed on the basis of left atrial phasic areas was enhanced during experimental cardiac volume loading in healthy dogs. The effect of volume load should be considered when evaluating left atrial phasic function by indices derived from left atrial phasic sizes.
  • K. Nakamura, T. Morita, T. Osuga, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 30 1 69 - 75 2016年01月01日 [査読有り][通常論文]
     
    Background: The right ventricular (RV) Tei index (TX) has a significant correlation with the severity of pulmonary hypertension. However, the role of RV dysfunction in dogs with myxomatous mitral valvular heart disease (MMVD) has not been addressed. Objectives: To investigate the correlation between right ventricular Tei-index (RVTX) and the prognosis for dogs with MMVD. Animals: Thirty client-owned dogs with MMVD. Methods: Clinical cohort study. Dogs were divided into two groups on the basis of the onset of cardiac-related death within 1 year of the first echocardiographic examination. Physical examination and echocardiographic variables were compared between the groups. Receiver operating characteristic (ROC) curves and multivariate logistic analysis were used to assess the comparative accuracy when identifying dogs with cardiac-related death. Results: The highest accuracy was obtained for RVTX with an area under the ROC curve (AUC) of 0.95 (95% confidence interval [CI] 0.81-0.99) followed by the left atrial to aortic root ratio with an AUC of 0.91 (95% CI 0.74-0.98), peak early diastolic mitral inflow velocity with an AUC of 0.84 (95% CI 0.64-0.94), and Doppler estimates of systolic pulmonary artery pressure with an AUC of 0.84 (95% CI 0.61-0.95). According to the multivariate logistic regression analysis, RVTX was the only independent correlate of cardiac-related death within 1 year. Conclusions and Clinical Importance: Right ventricular Tei-index has a strong correlation with the prognosis for dogs with MMVD. The most significant independent predictor of death was RVTX in this study.
  • T. Osuga, K. Nakamura, T. Morita, S. Y. Lim, K. Nisa, N. Yokoyama, N. Sasaki, K. Morishita, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 29 6 1518 - 1523 2015年11月 [査読有り][通常論文]
     
    BackgroundIn humans with heart disease, vitamin D deficiency is associated with disease progression and a poor prognosis. A recent study showed that serum 25-hydroxyvitamin D [25(OH)D] concentration, the hallmark of vitamin D status, was lower in dogs with heart failure than in normal dogs, and a low concentration was associated with poor outcome in dogs with heart failure. ObjectivesTo elucidate the vitamin D status of dogs with chronic valvular heart disease (CVHD) at different stages of disease severity. AnimalsForty-three client-owned dogs with CVHD. MethodsIn this cross-sectional study, dogs were divided into 3 groups (14 dogs in Stage B1, 17 dogs in Stage B2, and 12 dogs in Stage C/D) according to ACVIM guidelines. Dogs underwent clinical examination including echocardiography. Serum 25(OH)D concentrations were measured in each dog. ResultsSerum 25(OH)D concentration was significantly lower in Stage B2 (median, 33.2nmol/L; range, 4.9-171.7nmol/L) and C/D (13.1nmol/L; 4.9-58.1nmol/L) than in Stage B1 (52.5nmol/L; 33.5-178.0nmol/L) and was not significantly different between Stage B2 and Stage C/D. Among clinical variables, there were significant negative correlations between 25(OH)D concentration and both left atrial-to-aortic root ratio and left ventricular end-diastolic diameter normalized for body weight. Conclusions and Clinical ImportanceThese results indicate that vitamin D status is associated with the degree of cardiac remodeling, and the serum 25(OH)D concentration begins to decrease before the onset of heart failure in dogs with CVHD.
  • Noboru Sasaki, Clemens Bos, Jean-Michel Escoffre, Gert Storm, Chrit Moonen
    INTERNATIONAL JOURNAL OF PHARMACEUTICS 482 1-2 118 - 122 2015年03月 [査読有り][通常論文]
     
    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. (C) 2015 Published by Elsevier B.V.
  • Jean-Michel Escoffre, Roel Deckers, Noboru Sasaki, Clemens Bos, Chrit Moonen
    RADIOLOGY AND ONCOLOGY 49 1 41 - 49 2015年03月 [査読有り][通常論文]
     
    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 (R), a clinically approved antibody, targeting the human epidermal growth factor receptor 2 (HER-2) overexpressed in breast cancer. Results. Herceptin (R) was heated to 37 degrees C (control) and 42 degrees C (mHT) for 1 hour. Formation of Herceptin (R) aggregates was measured using Nile Red assay. mHT did not result in additional Herceptin (R) aggregates compared to 37 degrees C, showing the Herceptin (R) stability is unchanged. Immunological and pharmacological properties of Herceptin (R) were evaluated following mHT using HER-2 positive breast cancer cells (BT-474). Exposure of Herceptin (R) to mHT preserved recognition and binding affinity of Herceptin (R) to HER-2. Western-blot and cell proliferation assays on BT-474 cells showed that mHT left the inhibitory activities of Herceptin (R) unchanged. Conclusions. The stability, and the immunological and pharmacological properties of Herceptin (R) 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 (R).
  • S. Y. Lim, K. Nakamura, K. Morishita, N. Sasaki, M. Murakami, T. Osuga, N. Yokoyama, H. Ohta, M. Yamasaki, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 29 1 71 - 78 2015年01月 [査読有り][通常論文]
     
    Background: Quantitative contrast-enhanced ultrasonography ( CEUS) can detect pancreatic perfusion changes in experimentally induced canine pancreatitis. However, its usefulness in detecting perfusion changes in naturally occurring pancreatitis is unclear. Hypothesis/ Objectives: To determine the feasibility of using CEUS to detect pancreatic and duodenal perfusion changes in naturally occurring canine pancreatitis. Animals: Twenty-three client-owned dogs with pancreatitis, 12 healthy control dogs. Methods: Dogs diagnosed with pancreatitis were prospectively included. CEUS of the pancreas and duodenum were performed. Time-intensity curves were created from regions of interest in the pancreas and duodenum. Five perfusion parameters were obtained for statistical analyses: time to initial up-slope, peak time ( Tp), time to wash-out ( TTW), peak intensity ( PI), and area under the curve ( AUC). Results: For the pancreas, Tp of the pancreatitis group was prolonged when compared to controls ( 62 +/- 11 seconds versus 39 +/- 13 seconds; P <.001). TTW also was prolonged but not significantly ( 268 +/- 69 seconds versus 228 +/- 47 seconds; P =.47). PI and AUC were increased when compared to controls ( 95 +/- 15 versus 78 +/- 13 MPV; P =.009 and 14,900 +/- 3,400 versus 11,000 +/- 2,800 MPV* s; P =.013, respectively). For the duodenum, PI and AUC were significantly increased in the pancreatitis group when compared to controls. Conclusions and Clinical Importance: Contrast-enhanced ultrasonography can detect pancreatic perfusion changes in naturally occurring canine pancreatitis characterized by delayed peak with prolonged hyperechoic enhancement of the pancreas on CEUS. Additionally, duodenal perfusion changes secondary to pancreatitis were observed.
  • Hiroshi Ohta, Kanae Takada, Yuji Sunden, Yu Tamura, Tatsuyuki Osuga, Sue Yee Lim, Masahiro Murakami, Noboru Sasaki, Bandula Kumara Wickramasekara Rajapakshage, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 76 3 409 - 14 2014年03月 
    Inflammatory bowel disease (IBD) is a common cause of chronic gastrointestinal signs in dogs. In humans, T helper cells have important roles in the pathogenesis of IBD. In contrast, no specific involvement of a distinct T cell subset has been described in canine IBD. The present study evaluated the gene and protein expression of cytokines of T cell subsets in duodenal mucosa from dogs with IBD. Relative quantification of interleukin (IL)-17A, interferon (IFN)-γ, IL-4 and IL-10 mRNA transcription was performed using duodenal mucosa from 27 IBD dogs and 8 controls. Duodenal mucosal IL-17A, IFN-γ and IL-10 protein levels were determined by ELISA in 15 IBD dogs and 8 controls. There was no significant difference in each cytokines mRNA transcription level between groups. There was no significant difference in IL-17A, IFN-γ and IL-10 protein expression levels between groups. Thus, there is no clear evidence for the involvement of distinct Th cytokine in the pathogenesis of canine IBD.
  • 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 2014年01月 [査読有り][通常論文]
     
    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.
  • Sue Yee Lim, Kensuke Nakamura, Keitaro Morishita, Noboru Sasaki, Masahiro Murakami, Tatsuyuki Osuga, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 75 12 1601 - 1607 2013年12月 [査読有り][通常論文]
     
    Quantitative contrast enhanced ultrasound is a major breakthrough for ultrasound imaging in recent years. However, contrast enhancement of the pancreas is brief with bolus injection. To assess if continuous infusion of Sonazoid (R) can prolong the duration of pancreatic enhancement over bolus injections, eight adult dogs received bolus injection and continuous infusion of Sonazoid (R) on separate days. Contrast enhanced ultrasound of the pancreatic parenchyma and proximal descending duodenum was performed, and time intensity curves reflecting tissue perfusions were generated. Perfusion parameters- time to initial upslope, peak time, time to wash-out and peak intensity were calculated and evaluated. Fast wash-in to intense peak, followed by rapid wash-out was observed for time intensity curves of bolus injection. With continuous infusion, contrast wash-in to peak intensity was gradual, followed by long plateau and slow wash-out. Median contrast enhancement durations of the pancreas and duodenum were significantly prolonged by continuous infusion from 11 sec (range, 10 to 23 sec) and 16 sec (range, 3 to 43 sec) at bolus injection to 205 sec (range, 170 to 264 sec, P<0.01) and 193 sec (range, 169 to 216 sec, P<0.05), respectively. Median peak intensity of the pancreas was 100.9 MPV (range, 80.2 to 124.3 MPV) at bolus injection and 77.6 MPV (range, 58.2 to 99.5 MPV, P<0.05) at continuous infusion. Prolonged continuous imaging is afforded by continuous infusion of contrast agent. Peak intensity of the pancreas was slightly diminished in continuous infusion, but offered adequate imaging subjectively.
  • Hiroshi Ohta, Kanae Takada, Shidow Torisu, Masashi Yuki, Yu Tamura, Nozomu Yokoyama, Tatsuyuki Osuga, Sue Yee Lim, Masahiro Murakami, Noboru Sasaki, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 155 4 259 - 263 2013年10月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds are recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and a space-occupying large polyp in the colorectal area, and are thought to be a novel form of inflammatory bowel disease (IBD). In humans, specific cytokine patterns attributed to T helper (Th)1, Th17 and regulatory T cells have important roles in the pathogenesis of IBD. Thus, the aim of the present study was to assess the gene expression of cytokines of T cell subsets in the colorectal mucosa from dogs with ICRPs. Colorectal mucosal specimens from 10 dogs with ICRPs and 14 control dogs were used in this study. Interferon (IFN)-gamma, interleukin (IL)-4, IL-17A and IL-10 mRNA expression was assessed using quantitative real-time PCR. IL-17A mRNA expression was significantly increased in large polyps compared to small polyps and controls. IFN-gamma and IL-10 mRNA expression in large polyps were significantly higher than in controls. There was no significant difference in IL-4 mRNA expression among the three groups. IL-17A is thought to play important roles in the pathogenesis of ICRPs. IL-10 up-regulation could oppose the proinflammatory function of IL-17A. (C) 2013 Elsevier B.V. All rights reserved.
  • Tatsuyuki Osuga, Kensuke Nakamura, Sue Yee Lim, Yu Tamura, Wickramasekara Rajapakshage Bandula Kumara, Masahiro Murakami, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH 74 6 864 - 869 2013年06月 [査読有り][通常論文]
     
    Objective-To evaluate left atrial phasic function in healthy dogs by means of 2-D speckle tracking echocardiography with time-left atrial area curve analysis and to assess repeatability and reproducibility of obtained measurements. Animals-6 healthy Beagles. Procedures-Each dog underwent echocardiography twice on different days (3 nonconsecutive examinations/d). Images were analyzed with offline software; area of the left atrium was automatically calculated in each frame throughout the cardiac cycle to derive time-left atrial area curves. Variables used to assess left atrial phasic function (total, passive, and active emptying area and emptying fractions and mean active and total emptying rates) were calculated. Agreement between variables measured via speckle tracking echocardiography and a manual tracing method was assessed with modified Bland-Altman analysis. Withinday and between-day coefficients of variation were determined. Results-Mean +/- SD total, passive, and active emptying fractions of the left atrium were 49.8 +/- 3.5%, 27.7 +/- 4.0%, and 30.5 +/- 4.3%, respectively. Mean +/- SD total and active emptying rates were 16.0 +/- 2.5 cm(2)/s and 25.1 +/- 4.9 cm(2)/s, respectively. Within-day and between-day coefficients of variation were < 20% (range, 0.41% to 16.4%) for all variables except mean active emptying rate (between-day coefficient of variation, 29.2%). Agreement between variables measured via speckle tracking echocardiography and the manual tracing method was good, and differences between methods were nonsignificant. Conclusions and Clinical Relevance-Evaluation of left atrial phasic function via speckle tracking echocardiography was feasible; repeatability and reproducibility of measurements were adequate in healthy dogs. Studies are needed to determine clinical applicability in canine patients. (Am J Vet Res 2013;74:864-869)
  • Bandula Kumara Wickramasekara Rajapakshage, Masahiro Yamasaki, Shiang-Jyi Hwang, Noboru Sasaki, Masahiro Murakami, Yu Tamura, Sue Yee Lim, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 74 9 1139 - 1148 2012年09月 [査読無し][通常論文]
     
    The stability of the characteristics of the diminazene aceturate (DA)-resistant B. gibsoni isolate was initially determined in vitro. Part of the DA-resistant B. gibsoni isolate was cultured without DA for 4 weeks, and then newly exposed to 200 ng/m/ DA. As a result, this isolate could proliferate the same as the DA-resistant isolate, indicating that the characteristic of DA resistance was stable in the DA-resistant isolate. Additionally, the level of parasitemia in the DA-resistant isolate was comparatively lower than in the wild-type, suggesting that the proliferation potential of the DA-resistant isolate would be lower than that of the wild-type. Subsequently, to investigate the involvement of mitochondrial DNA (mtDNA) in DA resistance in B. gibsoni, the nucleotide sequences and deduced amino acid sequences of mitochondrial genes such as COXI, COXIII, and CYTb genes of the DA-resistant isolate, were compared with those of the wild-type. As a result, these three genes were not altered in the DA-resistant B. gibsoni isolate. Moreover, the transcription levels of COXI,COXIII, and CYTb genes were observed by semi-quantitative RT-PCR. As a result, the gene transcription of those genes in the DA-resistant isolate was not significantly altered. These results indicated that DA did not affect mtDNA directly in DA-resistant B. gibsoni. Thus, it is suggested that mtDNA should not be deeply involved in DA resistance in B. gibsoni.
  • Kensuke Nakamura, Masahiro Yamasaki, Tomohiro Osaki, Hiroshi Ohta, Noboru Sasaki, Keisuke Aoshima, Takashi Kimura, Mitsuyoshi Takiguchi
    JOURNAL OF THE AMERICAN ANIMAL HOSPITAL ASSOCIATION 48 5 327 - 330 2012年09月 [査読有り][通常論文]
     
    Bilateral segmental aplasia of the uterine horns with unilateral pyometra and uterine horn torsion were diagnosed in a Pomeranian bitch that presented with chronic abdominal distension and an acute onset of anorexia and lethargy. Because radiographic and ultrasonographic findings revealed the presence of markedly enlarged bilateral uterine horns filled with fluid in the caudal abdomen, a tentative diagnosis of either pyometra or hydrometra with uterine horn torsion was made. Exploratory laparotomy showed bilateral, segmentally distended uterine horns with unilateral uterine horn torsion. Ovariohysterectomy was performed, and bilateral segmental aplasia of the uterine horns with the development of unilateral uterine horn torsion was diagnosed histopathologically. To the authors' knowledge, this is the first report of uterine horn torsion in conjunction with segmental aplasia of the uterine horn in a bitch. (J Am Anim Hosp Assoc 2012; 48:327-330. DOI 10.5326/JAAHA-MS-5771)
  • Bandula Kumara Wickramasekara Rajapakshage, Masahiro Yamasaki, Masahiro Murakami, Yu Tamura, Sue Yee Lim, Tatsuyuki Osuga, Noboru Sasaki, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Japanese journal of veterinary research 60 2-3 51 - 61 2012年08月 [査読無し][通常論文]
     
    In our previous study, the level of parasitemia of the diminazene aceturate (DA)-resistant B. gibsoni isolate was continuously lower than that of the wild-type, indicating the possible alteration of energy metabolism in that isolate. Therefore, in the present study, the concentrations of ATP, glucose, lactate, and pyruvate, and the activities of lactate dehydrogenase and pyruvate kinase in the wild-type and DA-resistant isolate of B. gibsoni were measured and compared to investigate the amount of energy generation and the activity of the glycolysis pathway. As a result, the intracellular ATP and glucose concentrations in the DA-resistant B. gibsoni isolate were significantly higher than those in the wild-type. Meanwhile, the concentrations of lactate and pyruvate and the activities of lactate dehydrogenase and pyruvate kinase in the DA-resistant B. gibsoni isolate were not different from those in the wild-type. These results indicated that the DA-resistant B. gibsoni isolate contained a higher ATP concentration than the wild-type, but the activity of the glycolysis pathway was not altered in the DA-resistant B. gibsoni isolate. However, we could not determine the mechanism of the high energy production of the DA-resistant B. gibsoni isolate. Further studies on the energy metabolism of B. gibsoni are necessary to clarify the mechanism of the high energy production in the DA-resistant B. gibsoni isolate.
  • 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 AND BIOLOGY 38 1 109 - 118 2012年01月 [査読有り][通常論文]
     
    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 (R) 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. (E-mail: mtaki@vetmed.hokudai.ac.jp) (C) 2012 World Federation for Ultrasound in Medicine & Biology.
  • Noboru Sasaki, Kensuke Nakamura, Masahiro Murakami, Sue Yee Lim, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    11TH INTERNATIONAL SYMPOSIUM ON THERAPEUTIC ULTRASOUND 1481 307 - 310 2012年 [査読有り][通常論文]
     
    Diagnostic ultrasound has accomplished drug and gene delivery by ultrasound targeted microbubble destruction (UTMD). However, the efficacy of delivery is still relatively low. Therefore, we optimized conditions of UTMD using diagnostic ultrasound and ultrasound contrast agent microbubbles. Canine thyroid adenocarcinoma cells were cultured in a 96-well plate. After addition of cisplatin and Sonazoid (R), the plate was inverted to raise microbubbles near cells and incubated. Cells were exposed to diagnostic ultrasound using a linear probe operated in the contrast harmonic imaging mode. The center frequency was 2.5 MHz with a mechanical index of 1.33 and a frame rate of 48 frames/sec. Cytotoxic effect of cisplatin was evaluated 24h after exposure using trypan blue dye exclusion test. We optimized incubation duration, cisplatin concentration, and the relationship between microbubble concentration and exposure duration. The optimum enhancement was observed at incubation duration of 5min, cisplatin concentration of 1 mu g/ml, and microbubble concentration of 2.4 x 10(5) microbubbles/ml. Exposure duration did not influence the enhancement at the microbubble concentration of 2.4 x 10(5) microbubbles/ml. Our results suggest that relative low concentrations of drug and microbubbles with short exposure duration might be sufficient for drug delivery by UTMD using diagnostic ultrasound.
  • Masahiro Yamasaki, Norihisa Tamura, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Wickramasekara Rajapakshage, Bandula Kumara, Yu Tamura, Sue Yee Lim, Hiroshi Ohta, Mitsuyoshi Takiguchi
    JOURNAL OF PARASITOLOGY 97 6 1190 - 1192 2011年12月 [査読有り][通常論文]
     
    Nystatin is a membrane-active polyene macrolide antibiotic and a channel-forming ionophore. Nystatin exhibits in vitro activity against Babesia gibsoni infecting normal canine erythrocytes containing low potassium (LK) and high sodium concentrations, i.e., LK erythrocytes. The calculated IC(50) value of nystatin against B. gibsoni infecting LK erythrocytes was 31.96 mu g/ml. The anti-babesial activity of nystatin disappeared when B. gibsoni in LK erythrocytes were incubated in culture media containing high potassium concentrations (HK). Moreover, when the parasites were harbored in canine HK erythrocytes, which contained high potassium and low sodium concentrations as a result of high Na-K-ATPase activity, the in vitro anti-babesial activities of nystatin also disappeared, apparently due to protection by HK erythrocytes. This suggested that nystatin could show in vitro anti-babesial activity against B. gibsoni by its ionophorous activity, the same as other ionophores such as valinomycin. Subsequently, the effects of nystatin on the host cells were observed. Nystatin could not modify the intracellular concentrations of potassium, sodium, adenosine triphosphate, or glucose in either LK or HK erythrocytes, although it caused weak hemolysis in HK erythrocytes. In addition, nystatin did not affect the survival of canine peripheral polymorphonuclear leukocytes. In conclusion, nystatin destroyed B. gibsoni by ionophorous activity but did not affect either canine erythrocytes or leukocytes in vitro.
  • K. Nakamura, M. Yamasaki, H. Ohta, N. Sasaki, M. Murakami, W. R. Bandula Kumara, M. Takiguchi
    JOURNAL OF SMALL ANIMAL PRACTICE 52 11 595 - 598 2011年11月 [査読無し][通常論文]
     
    Objectives: To determine the effect of sildenafil for dogs with Eisenmeger's syndrome and secondary erythrocytosis.
  • Hiroshi Ohta, Tomoki Yamaguchi, B. K. Wickramasekara Rajapakshage, Masahiro Murakami, Noboru Sasaki, Kensuke Nakamura, Shiang-Jyi Hwang, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH 72 8 1046 - 1051 2011年08月 [査読無し][通常論文]
     
    Objective-To examine the expression and distribution of tight junction (TJ) and adherens junction (AM proteins in canine duodenal and colonic mucosa. Sample-Mucosa obtained from 4 healthy Beagles. Procedures-Biopsy specimens of the duodenum and colon were obtained via endoscopy from 4 healthy dogs. The expression patterns and subcelluar localization of claudin-1, -2, -3, -4, -5, -7, and -8; E-cadherin; and beta-catenin in the duodenum and colon were analyzed by use of immunoblotting and immunofluorescence microscopy. Results-In the duodenum, there was clear expression of claudin-3 and -5, E-cadherin, and beta-catenin proteins and weak expression of claudin-7 protein. In contrast, there was clear expression of claudin-2 and -3, E-cadherin, and beta-catenin proteins and weak expression of claudin-5 and -7 proteins in the colon, as determined by use of immunoblotting. As determined by the use of immunofluorescence microscopy, the duodenum and colon had staining for claudin-3 and -5, E-cadherin, and beta-catenin in the most apical region and staining for claudin-7 in the basolateral region. Staining for claudin-2 was also observed in the colon. Conclusions and Clinical Relevance-Information was provided about the expression patterns of TJ and AJ proteins in the duodenum and colon of clinically normal dogs. These results may provide valuable information for use in evaluating the importance of these TJ and AJ proteins in the pathogenesis of inflammatory bowel disease in dogs. (Am J Vet Res 2011;72:1046-1051)
  • Masahiro Yamasaki, Mikiko Ishida, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Wickramasekara Rajapakshage Bandula Kumara, Yu Tamura, Sue Yee Lim, Hiroshi Ohta, Mitsuyoshi Takiguchi
    VETERINARY PARASITOLOGY 180 3-4 215 - 225 2011年08月 [査読無し][通常論文]
     
    Antibodies that recognized either Babesia gibsoni or canine red blood cell (RBC) 70-kilodalton (kDa) protein were detected in serum from acutely and chronically B. gibsoni-infected. In those sera, antibodies that reacted with recombinant B. gibsoni and canine heat shock protein 70 (rBgHsp70 and rcHsp70) were detected; therefore, B. gibsoni and canine RBC 70-kDa proteins seemed to be BgHsp70 and cHsp70, respectively. In infected dogs, the amounts of these antibodies increased after infection. Interestingly, polyclonal antibody raised against rBgHsp70 in two rabbits reacted not only with rBgHsp70 but also with rcHsp70 and native cHsp70 from canine RBCs. Because BgHsp70 showed high homology with cHsp70 (70.8%), anti-rBgHsp70 antibody might cross-react with cHsp70. Additionally, the localizations of both BgHsp70 and cHsp70 were observed by indirect fluorescence assay. As a result, cHsp70 was not found on the membrane surface of erythrocytes, suggesting that erythrocytes would not be targets of anti-cHsp70 antibody. Meanwhile, only exoerythrocytic parasites were stained by anti-rBgHsp70 antibody. This result showed that BgHsp70 would be expressed on the surface of parasites during the exoerythrocytic stage. These results indicated that BgHsp70 was a highly immunogenic protein in canine B. gibsoni infection, and that exoerythrocytic parasites might be targets of anti-BgHsp70 antibody. (C) 2011 Elsevier B.V. All rights reserved.
  • Hiroshi Ohta, Tomoki Yamaguchi, B. K. Wickramasekara Rajapakshage, Masahiro Murakami, Noboru Sasaki, Kensuke Nakamura, Shiang-Jyi Hwang, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH 72 8 1046 - 1051 2011年08月 [査読有り][通常論文]
     
    Objective-To examine the expression and distribution of tight junction (TJ) and adherens junction (AM proteins in canine duodenal and colonic mucosa. Sample-Mucosa obtained from 4 healthy Beagles. Procedures-Biopsy specimens of the duodenum and colon were obtained via endoscopy from 4 healthy dogs. The expression patterns and subcelluar localization of claudin-1, -2, -3, -4, -5, -7, and -8; E-cadherin; and beta-catenin in the duodenum and colon were analyzed by use of immunoblotting and immunofluorescence microscopy. Results-In the duodenum, there was clear expression of claudin-3 and -5, E-cadherin, and beta-catenin proteins and weak expression of claudin-7 protein. In contrast, there was clear expression of claudin-2 and -3, E-cadherin, and beta-catenin proteins and weak expression of claudin-5 and -7 proteins in the colon, as determined by use of immunoblotting. As determined by the use of immunofluorescence microscopy, the duodenum and colon had staining for claudin-3 and -5, E-cadherin, and beta-catenin in the most apical region and staining for claudin-7 in the basolateral region. Staining for claudin-2 was also observed in the colon. Conclusions and Clinical Relevance-Information was provided about the expression patterns of TJ and AJ proteins in the duodenum and colon of clinically normal dogs. These results may provide valuable information for use in evaluating the importance of these TJ and AJ proteins in the pathogenesis of inflammatory bowel disease in dogs. (Am J Vet Res 2011;72:1046-1051)
  • Masahiro Yamasaki, Yusuke Kobayashi, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Bandula Kumara Wickramasekara Rajapakshage, Hiroshi Ohta, Osamu Yamato, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    EXPERIMENTAL PARASITOLOGY 127 1 119 - 126 2011年01月 [査読無し][通常論文]
     
    In this study, we attempted to detect Babesia gibsoni in blood smears and formalin-fixed, paraffin-embedded tissues obtained from B. gibsoni-infected dogs using in situ hybridization. Using a digoxigenin-conjugated deoxyribonucleic acid (DNA) probe, both intraerythrocytic and exoerythrocytic parasites in the culture could be specifically stained in blood smears fixed with 4% phosphate-buffered paraformaldehyde. This indicated that genomic DNA extracted from the parasites could be detected using in situ hybridization. Moreover, the parasite could be specifically stained in paraffin-embedded spleen, lymph node, and kidney sections using in situ hybridization. Infected erythrocytes in blood vessels in the spleen and kidney, hemosiderin-laden macrophages in the spleen, and phagocytized erythrocytes, which seemed to be infected with the parasites, in lymph nodes were also specifically stained. This suggests that in situ hybridization can be utilized to investigate both the life cycle of B. gibsoni and the pathological condition of canine babesiosis. (C) 2010 Elsevier Inc. All rights reserved.
  • K. Nakamura, N. Sasaki, M. Murakami, W. R. Bandula Kumara, H. Ohta, M. Yamasaki, S. Takagi, T. Osaki, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 24 6 1290 - 1297 2010年11月 [査読無し][通常論文]
     
    Background: Contrast-enhanced ultrasonography with perflubutane microbubbles improves the diagnostic accuracy to differentiate benign and malignant focal liver lesions in dogs. Hypothesis: Perflubutane microbubbles-enhanced ultrasonography is useful for differentiation of benign from malignant focal splenic lesions in dogs. Animals: Twenty-nine clinical dogs with single or multiple focal splenic lesions detected by conventional ultrasonography. Methods: Prospective clinical observational study. Perflubutane microbubbles-enhanced ultrasonography was performed in 29 dogs with focal splenic lesions. Qualitative assessment of the enhancement pattern was performed in the early vascular, late vascular, and parenchymal phases. Results: In the early vascular phase, a hypoechoic pattern was significantly associated with malignancy (P = .02) with sensitivity of 38% (95% confidence interval [CI], 25-38%) and specificity of 100% (95% CI, 84-100%). In the late vascular phase, a hypoechoic pattern was significantly associated with malignancy (P = .001) with sensitivity of 81% (95% CI, 66-90%) and specificity of 85% (95% CI, 65-95%). There was no significant difference between malignant and benign lesions during the parenchymal phase. Conclusions and Clinical Importance: Hypoechoic splenic nodules in the early and late vascular phases with perflubutane microbubbles-enhanced ultrasonography are strongly suggestive of malignancy in dogs.
  • Shiang-Jyi Hwang, Masahiro Yamasaki, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Bandula Kumara Wickramasekara Rajapakshage, Hiroshi Ohta, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    JAPANESE JOURNAL OF VETERINARY RESEARCH 58 3-4 155 - 164 2010年11月 [査読有り][通常論文]
     
    In our previous report, we developed a diminazene aceturate (DA)-resistant Babesia gibsoni strain that was maintained in culture with 200 ng/ml DA. While developing this strain, we also obtained DA-resistant B. gibsoni variants, which were maintained in culture with DA from 1 to 175 ng/ml for more than 8 weeks. Because heat shock protein 70 (Hsp70) seems to play important roles in adaptation to a stress environment in protozoan parasites, in the present study, we examined the copy number of B. gibsoni Hsp70 (BgHsp70) transcripts of those DA-resistant variants using quantitative real-time reverse transcription-polymerase chain reaction. We found that when wild-type B. gibsoni was exposed to 1 ng/ml DA, the level of BgHsp70 transcripts was decreased at day 14. The copy number of BgHsp70 transcripts in the DA-resistant variant cultured with 1 ng/ml DA was significantly lower than in wild-type B. gibsoni, while those in DA-resistant variants increased with escalating doses of DA from 1 to 75 ng/ml, although they were lower than in wild-type B. gibsoni. However, those in DA-resistant variants cultured with > 125 ng/ml DA were almost the same as wild-type B. gibsoni. These results indicated that the transcript levels of the BgHsp70 gene might be reduced when the parasites are exposed to a low concentration of DA, and then might recover to the normal level after achieving resistance against DA. We expect that further study of the function of BgHsp70 will elucidate the mechanism of drug resistance against DA in B. gibsoni.
  • Shiang-Jyi Hwang, Masahiro Yamasaki, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Bandula Kumara Wickramasekara Rajapakshage, Hiroshi Ohta, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 72 6 765 - 771 2010年06月 [査読無し][通常論文]
     
    We attempted to develop a strain of Babesia gibsoni resistant to diminazene aceturate (DA), an anti-babesial drug, in vitro. Since the DA-sensitive B. gibsoni strain could survive and proliferate in culture medium containing 1 ng/ml DA, the concentration of DA was gradually increased from 1 to 200 ng/ml. The results showed that the parasites could survive and proliferate in the medium containing 200 ng/ml DA, which was much higher than the 50% inhibitory concentration (IC(50)) of DA for B. gibsoni. Subsequently, these parasites were removed from erythrocytes and exposed directly to 200 ng/ml DA. They were able to survive and invade fresh erythrocytes, though the DA-sensitive B. gibsoni strain did not survive. Based on these results, the parasites cultured within 200 ng/ml DA were determined to be a DA-resistant B. gibsoni strain. In addition, the IC(50) levels of clindamycin, doxycycline and pentamidine for the DA-resistant B. gibsoni strain were determined. The IC(50) levels of clindamycin, doxycycline and pentamidine for the DA-resistant strain were higher than those for the DA-sensitive strain. The IC(50) of pentamidine for the resistant strain was much greater than that for the DA-sensitive strain. These results indicated that the DA-resistant B. gibsoni strain could have resistance not only to DA, but also to other anti-babesial drugs. In conclusion, we successfully developed a DA-resistant B. gibsoni strain in vitro.
  • Kensuke Nakamura, Satoshi Takagi, Noboru Sasaki, Wickramasekara Rajapakshage Bandula Kumara, Masahiro Murakami, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY RADIOLOGY & ULTRASOUND 51 1 79 - 85 2010年01月 [査読無し][通常論文]
     
    In six normal beagles and 27 dogs with spontaneous focal or multifocal liver lesions, contrast-enhanced ultrasonography using Sonazoid (R) was performed. Sonazoid (R) is a newly developed second-generation contrast agent with the ability to be used for real-time contrast imaging along with parenchymal imaging. An appropriate protocol for the evaluation of all three phases (arterial, portal, and parenchymal) was established based on the results for normal beagles. By evaluation of the echogenicity of hepatic nodules during the arterial and parenchymal phases it was possible to differentiate malignant tumors from benign nodules with very high accuracy. In 15 of 16 dogs diagnosed as malignant tumors, nodules were clearly hypoechoic to the surrounding normal liver during the parenchymal phase. Additionally, malignant tumors had different echogenicity compared with the surrounding normal liver during the arterial phase in 14 of 15 dogs. In the portal phase, there were no characteristic findings. Contrast-enhanced ultrasonography with Sonazoid (R) appears to improve the characterization of canine focal and multifocal hepatic lesions.
  • Masahiro Yamasaki, Kensuke Nakamura, Norihisa Tamura, Shiang-Jyi Hwang, Muneyoshi Yoshikawa, Noboru Sasaki, Hiroshi Ohta, Osamu Yamato, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    JOURNAL OF PARASITOLOGY 95 6 1532 - 1538 2009年12月 [査読無し][通常論文]
     
    Valinomycin and salinomycin-Na, 2 ionophorous antibiotics, exhibited in vitro antibabesial activities against Babesia gibsoni that infected normal canine erythrocytes containing low potassium (LK) and high sodium concentrations, i.e., LK erythrocytes, which completely lack Na,K-ATPase activity. The level of parasitemia of B. gibsoni was significantly decreased when the parasites were incubated in culture medium containing either 10(-1) ng/ml valinomycin or 10(2) ng/ml salinomycin-Na for 24 hr. Four-hour incubation in the culture medium containing 5 mu g/ml salinomycin-Na led to the destruction of most parasites. In contrast, when the parasites infected canine erythrocytes containing high potassium (HK) and low sodium concentrations, i.e., HK erythrocytes, the in vitro antibabesial activities of both ionophorous antibiotics seemed to be weakened, apparently due to the protection by the host cells. Therefore, differential influences of ionophorous antibiotics on LK and HK erythrocytes were observed. In LK erythrocytes, the intracellular concentrations of potassium, sodium, and adenosine triphosphate (ATP) were not modified, and hemolysis was not observed after incubation in the medium containing each ionophorous antibiotic. These results suggested that these ionophorous antibiotics did not affect cells without Na,K-ATPase, and directly affected B. gibsoni. In HK erythrocytes, the ionophorous antibiotics increased the intracellular sodium concentration, and decreased the intracellular potassium and ATP concentrations, causing obvious hemolysis. Additionally, the decrease of the intracellular ATP concentration and the hemolysis in HK erythrocytes caused by valinomycin disappeared when the activity of Na,K-ATPase was inhibited by ouabain. These results indicate that modification of the intracellular cation concentrations by the ionophorous antibiotics led to the activation of Na,K-ATPase and increased consumption of intracellular ATP, and that the depletion of intracellular ATP resulted in hemolysis in HK erythrocytes. Moreover, the antibabesial activity of valinomycin disappeared when B. gibsoni in LK erythrocytes were incubated in culture media containing high potassium concentrations. This showed that the intracellular cation concentration in the parasites was not modified in those media and would remain the same.
  • Hiroshi Ohta, Satoshi Takagi, Masahiro Murakami, Noboru Sasaki, Muneyoshi Yoshikawa, Kensuke Nakamura, Shiang-Jyi Hwang, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 71 11 1533 - 1535 2009年11月 [査読無し][通常論文]
     
    A 7-year-old female Boston terrier was referred to Hokkaido University Veterinary Teaching Hospital with a history of hemoglobinuria and anemia for several days. Abdominal radiographs showed splenomegaly, and Ultrasonography revealed a hypoechoic splenic parenchyma with interspersed linear echoes consistent with the ultrasonographic appearance of splenic torsion. Ultrasonography and computed tomography (CT) indicated a C-shaped spleen. Exploratory laparotomy confirmed the diagnosis of splenic torsion. A splenectomy was performed, and the dog recovered well Without complications. This is the first report of splenic torsion in Boston terriers, and the usefulness of ultrasonographic and CT findings of the splenic torsion was also confirmed.
  • Kensuke Nakamura, Noboru Sasaki, Muneyoshi Yoshikawa, Hiroshi Ohta, Shiang-Jyi Hwang, Takahiro Mimura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY RADIOLOGY & ULTRASOUND 50 1 104 - 108 2009年01月 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography has an important role in the detection of tumors in humans. The second-generation contrast agent Sonazoid has the ability of real-time contrast imaging along with parenchymal imaging. The purposes of this study were to determine the effect and duration of Sonazoid on the changes in gray-scale enhancement of canine spleen and to establish an appropriate protocol for contrast-enhanced ultrasonography of canine spleen. Six healthy beagles were injected with an intravenous bolus of Sonazoid. In the spleen parenchyma, the enhancement was maintained up to 30 min after injection. Moreover, for 5-22 s after injection, gray-scale enhancement of splenic arteries afforded arterial imaging. Perfusion of the kidney may be investigated from 3.6 s to 3.5 min after injection of Sonazoid. These results suggest that Sonazoid is applicable to canine spleen parenchymal imaging and that the optimal time for the parenchymal imaging is 7-30 min after injection. The findings of this quantitative study should prove useful in the evaluation of diffuse or focal splenic and renal diseases in dogs.

MISC

  • 近藤 隆, 鈴木 亮, 佐々木 東, 滝口 満喜 Thermal Medicine 36 (3) 75 -90 2020年09月 
    超音波の作用は熱作用と非熱作用に大別され、非熱作用はキャビテーション作用と非キャビテーション作用に分けられる。以前、超音波による癌治療としては、1)超音波単独(主にハイパーサミア治療)、2)放射線治療との併用、および3)化学療法との併用があった。近年、超音波に関する生物学・基礎医学に関して、細胞死、遺伝子発現、遺伝子導入、化学物質との相互作用、薬物送達等の研究が進展してきた。とりわけ、微小気泡は診断のみならず治療のツールとして注目され、その研究は大きく発展してきた。臨床応用も集束超音波治療、低強度パルス波超音波治療、加えて血液-脳-関門の開口に関する技術の進展が著しい。本総説では、超音波による癌治療に関して、歴史的経緯を述べるとともに最近の熱作用および非熱作用を利用した癌治療についてその可能性と課題について考察する。(著者抄録)
  • Two-dimensional shear wave elastographyによる非侵襲的な犬の肝線維化診断
    田村 昌大, 大田 寛, 大菅 辰幸, 新坊 弦也, 佐々木 東, 森下 啓太郎, 賀川 由美子, 滝口 満喜 日本獣医麻酔外科学雑誌 50 (Suppl.2) 315 -315 2019年12月 [査読無し][通常論文]
  • 鈴木智裕, 池中良徳, 中山翔太, 水川葉月, 一瀬貴大, 佐々木東, 笹岡一慶, 石塚真由美 日本獣医学会学術集会講演要旨集 162nd 501 2019年08月20日 [査読無し][通常論文]
  • 下垂体性副腎皮質機能亢進症に対して定位放射線治療を実施した犬の3例
    今井 健友, 出口 辰弥, 細谷 謙次, 森下 啓太郎, 金 尚昊, 佐々木 東, 大菅 辰幸, 奥村 正裕 北海道獣医師会雑誌 63 (8) 345 -345 2019年08月
  • 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 2019年08月 [査読無し][通常論文]
  • 白尾 大樹, 池中 良徳, 一瀬 貴大, 中山 翔太, 佐々木 東, 永田 矩之, 水川 葉月, 滝口 満喜, 石塚 真由美 日本獣医学会学術集会講演要旨集 162回 470 -470 2019年08月 [査読無し][通常論文]
  • 蚕白喪失性腸症の犬40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, 佐々木 東, 大菅 辰幸, 森下 啓太郎, 滝口 満喜 日本獣医師会雑誌 72 (4) 234 -235 2019年04月
  • 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 2019年04月 [査読無し][通常論文]
  • Shear Wave Elastographyによる犬の肝硬度評価の試み
    田村 昌大, 森下 啓太郎, 新坊 弦也, 佐々木 東, 大田 寛, 滝口 満喜 日本獣医画像診断学会抄録 64回 13 -13 2018年11月
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 健康な犬における二次元スペックルトラッキング心エコーによる左心室長軸方向ストレイン解析に与える心臓容積負荷の影響(Effect of cardiac volume loading on left atrial longitudinal strain analysis derived from two-dimensional Speckle Tracking Echocardiography in healthy dogs)
    Dermlim Angkhana, 中村 健介, 森田 智也, 大菅 辰幸, Nisa Khoirun, Leela-arporn Rommaneeya, 笹岡 一慶, 永田 矩之, 田村 昌大, 佐々木 東, 大田 寛, 森下 啓太郎, 滝口 満喜 日本獣医学会学術集会講演要旨集 161回 435 -435 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 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 2018年08月 [査読無し][通常論文]
  • 佐々木 東, 中山 翔太, 大田 寛, 大菅 辰幸, 森下 啓太郎, 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 161回 429 -429 2018年08月 [査読無し][通常論文]
  • 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 2018年07月 [査読無し][通常論文]
  • 慢性僧帽弁疾患犬において右室strainによる右心室機能評価は優れた予後指標となり得るか
    森田 智也, 中村 健介, 大菅 辰幸, 森下 啓太郎, 佐々木 東, 大田 寛, 滝口 満喜 SA Medicine 20 (3) 68 -70 2018年06月 [査読無し][通常論文]
  • 【皮膚の不快感】 外部寄生虫症
    佐々木 東 J-VET 31 (6) 25 -33 2018年06月 [査読無し][通常論文]
  • 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 2018年04月 [査読無し][通常論文]
  • 犬の蛋白漏出性腸症の予後因子解析 超音波検査所見の有用性の検討
    大田 寛, 賀川 由美子, 大菅 辰幸, 佐々木 東, 森下 啓太郎, 滝口 満喜 日本獣医師会雑誌 71 (4) 206 -207 2018年04月
  • 犬の蛋白漏出性腸症の予後因子解析 超音波検査所見の有用性の検討
    大田 寛, 賀川 由美子, 大菅 辰幸, 佐々木 東, 森下 啓太郎, 滝口 満喜 日本獣医師会雑誌 71 (4) 206 -207 2018年04月 [査読無し][通常論文]
  • 生前診断に苦慮した化膿性腸炎の猫の1例
    森下 啓太郎, 中島 彩乃, 賀川 由美子, 華園 究, 佐々木 東, 大田 寛, 滝口 満喜 日本獣医画像診断学会抄録 62回 6 -6 2017年09月 [査読無し][通常論文]
  • 生前診断に苦慮した化膿性腸炎の猫の1例
    森下 啓太郎, 中島 彩乃, 賀川 由美子, 華園 究, 佐々木 東, 大田 寛, 滝口 満喜 日本獣医画像診断学会抄録 62回 6 -6 2017年09月
  • 慢性肺動脈塞栓性肺高血圧症モデル犬を用いたピモベンダンの作用に関する検討
    森田 智也, 中村 健介, 大菅 辰幸, 森下 啓太郎, 佐々木 東, 大田 寛, 滝口 満喜 日本獣医学会学術集会講演要旨集 160回 465 -465 2017年08月 [査読無し][通常論文]
  • 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 2017年08月 [査読無し][通常論文]
  • 佐々木 東, 工藤 信樹, 中山 翔太, 滝口 満喜 超音波techno 29 (4) 27 -30 2017年07月 [査読無し][通常論文]
  • 佐々木東, 工藤信樹, 中村健介, 森下啓太郎, 大田寛, 滝口満喜 再生医療 16 348 2017年02月01日 [査読無し][通常論文]
  • 佐々木東, 工藤信樹, 森下啓太郎, 大田寛, 滝口満喜 日本超音波医学会光超音波画像研究会プログラム・抄録集 2017 (2nd) 66‐67 2017年 [査読無し][通常論文]
  • 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 2016年09月 [査読無し][通常論文]
  • 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 2016年09月 [査読無し][通常論文]
  • 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
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  • ジミナゼン耐性株および野生株におけるBabesia gibsoniミトコンドリアDNAの塩基配列の比較
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  • 中村健介, 高木哲, 山崎真大, 大田寛, 佐々木東, 滝口満喜 日本獣医師会三学会年次大会講演要旨集 2009 237 2010年01月07日 [査読無し][通常論文]
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  • 大田 寛, 村上 正紘, Bandura Kumara, 佐々木 東, 中村 健介, 黄 香寂, 山埼 真大, 滝口 満喜 日本獣医学会学術集会講演要旨集 148回 261 -261 2009年09月 [査読無し][通常論文]
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  • 中村 健介, 高木 哲, 佐々木 東, 村上 正紘, 大田 寛, 山崎 真大, 滝口 満喜 北海道獣医師会雑誌 53 (8) 101 -101 2009年08月 [査読無し][通常論文]
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    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 2008年11月 [査読無し][通常論文]
  • 犬の肝臓における造影超音波検査の有用性の検討
    中村 健介, 佐々木 東, 芳川 宗義, 黄 香寂, 大田 寛, 山崎 真大, 滝口 満喜 日本獣医学会学術集会講演要旨集 146回 265 -265 2008年09月 [査読無し][通常論文]
  • 山口 朋生, 大田 寛, 中村 健介, 黄 香寂, 佐々木 東, 芳川 宗義, 山崎 真大, 滝口 満喜 日本獣医学会学術集会講演要旨集 146回 258 -258 2008年09月 [査読無し][通常論文]
  • エリスロポエチン依存性の二次性多血症が疑われた腎リンパ腫の犬の1例
    佐々木 東, 芳川 宗義, 中村 健介, 大田 寛, 山崎 真大, 佐藤 耕太, 滝口 満喜 北海道獣医師会雑誌 52 (8) 415 -415 2008年08月 [査読無し][通常論文]
  • 中村 健介, 佐々木 東, 芳川 宗義, 大田 寛, 山崎 真大, 大場 雅予, 滝口 満喜 北海道獣医師会雑誌 52 (8) 410 -410 2008年08月 [査読無し][通常論文]
  • 芳川 宗義, 庄田 雅人, 中村 健介, 佐々木 東, 大田 寛, 山崎 真大, 滝口 満喜 北海道獣医師会雑誌 52 (8) 410 -410 2008年08月 [査読無し][通常論文]
  • 正常犬の血中遊離サイロキシン濃度および血中TSH濃度の生理的変動の評価
    佐々木 東, 山崎 真大, 大田 寛, 前出 吉光 日本獣医学会学術集会講演要旨集 144回 152 -152 2007年08月 [査読無し][通常論文]
  • 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 2006年08月 [査読無し][通常論文]

共同研究・競争的資金等の研究課題

  • マダニ媒介性感染症研究のボトルネック解消に向けたマダニ実験基盤の国際共同構築
    日本学術振興会:科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(B))
    研究期間 : 2020年10月 -2024年03月 
    代表者 : 中尾 亮, 佐々木 東, 邱 永晋
  • 血管内で振動する微小気泡が血管内皮と血管透過性に与える機械的・生理的作用の解明
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 工藤 信樹, 鈴木 亮, 松崎 典弥, 佐々木 東
  • 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
    日本学術振興会:科学研究費助成事業 若手研究
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 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。
  • 細胞・微小気泡間相互作用のその場観察によるソノポレーションの機序解明と応用拡大
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2017年04月 -2021年03月 
    代表者 : 工藤 信樹, 松崎 典弥, 鈴木 亮, 佐々木 東
     
    【ソノポレーション観察】(工藤)高速度観察,共焦点顕微観察,落射蛍光観察機能をポートの切り替えのみで実現できる顕微鏡観察システムを開発した.共焦点顕微鏡でも高速度撮影が可能な照明光強度を実現できる光学系を開発した.また,NAが大きい対物レンズを用いてソノポレーションにおける細胞と気泡の相互作用を高画質・高速報観察できる手法を新たに考案し,これを実現する観察チャンバを開発,有効性を確認した. 【ゲル毛細血管モデル】(工藤)毛細血管内における気泡のダイナミクスを解明するために,硬さが生体組織とほぼ等しいアクリルアミドゲルを用いて直径10-60ミクロンの管腔構造を持つゲル毛細血管モデルを作成する手法を開発した.モデルを用いて内腔における微小気泡の膨張・収縮を高速度観察し,モデルの有用性を確認した. 【3次元細胞培養を用いた毛細血管網モデル】(松崎,工藤)松崎の開発手法を参考に,3次元細胞培養技術を用いた毛細血管網モデルの作成について検討した.コラーゲンゲル内でヒト臍帯静脈内皮細胞を培養する手法を用いて,工藤の研究室でも毛細血管網モデル作成することに成功した.さらに,管腔内に気泡を導入する方法,超音波照射での観察手法についても検討し,作成モデルがソノポレーション研究に利用可能であることを確認した.モデルの再現性等については,検討を続ける. 【樹状細胞へのソノポレーション】(鈴木)株化樹状細胞(DC2.4)を用いて,浮遊細胞に準じた状態(細胞骨格が未発達な状態)で接着培養する手法を開発した.この手法を用いて,付着状態と準浮遊状態の細胞,気泡が表面に付着した細胞と気泡を貪食した細胞を用いてソノポレーション現象の違いを調べる実験を開始した.
  • 日本学術振興会:科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2018年06月 -2020年03月 
    代表者 : 滝口 満喜, 佐々木 東, 稲波 修
     
    中枢神経再生の第1ステップである神経突起の伸展と発芽を低強度パルス超音波で制御する試みを行った。ラット初代培養神経細胞に軸索進展阻害因子を作用させ、神経突起を萎縮させた。そこへ低強度パルス超音波を照射し、神経突起の様子を経時的に観察した。低強度パルス超音波により、1つの神経細胞あたりの神経突起は長くなったが、神経突起の起始点の数には変化がなかった。また、生きた細胞の細胞骨格を染色し、低強度パルス超音波照射中の細胞変形の観察に成功した。
  • 2018年度秋山記念生命科学研究助成 奨励
    研究期間 : 2018年04月 -2019年03月
  • 第36回カシオ科学振興財団研究助成
    研究期間 : 2018年04月 -2019年03月
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2016年04月 -2018年03月 
    代表者 : 佐々木 東
     
    ドラッグデリバリーはガン組織での抗がん剤濃度を高め、正常な組織を保護することのできる技術である。超音波と微小気泡を用いる「ソノポレーション」もその1つである。この組み合わせは既に診断法として普及しているため、安全であり臨床応用に近い。これまで、抗がん剤がどのくらいの距離までデリバリーできるか、抗がん剤がデリバリーできる時間は不明であった。本研究では動物を使わない3次元培養使い、1回のソノポレーションによって100 μmまでデリバリー可能であり、なおかつデリバリー可能時間は1時間と明らかにした。今後、この結果に基づき、臨床応用するための治療プロトコールを作成することができる。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 滝口 満喜, 中村 健介, 佐々木 東, 工藤 信樹
     
    超音波による診断と治療の融合の確立に向けた基盤を形成し、臨床応用へと発展させることを目的とし、犬の甲状腺癌および膀胱癌に対する超音波とマイクロバブルを用いた実用的な新規がん治療法「ソノポレーション」に関する前臨床段階の知見を得た。また、ソノポレーションの新たなメカニズムを明らかにすることで、臨床応用の基盤を構築した。
  • ホーユー科学財団平成28年度研究助成
    研究期間 : 2016年04月 -2017年03月
  • 日本学術振興会:科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2014年04月 -2016年03月 
    代表者 : 滝口 満喜, 佐々木 東
     
    本研究では、マイクロバブル(MB)存在下での超音波照射に引く続く放射線照射が、放射線誘発アポトーシスの増強効果を示すかを明らかにすることを目的とした。マウス扁平上皮癌細胞にMB存在下で超音波照射直後に放射線を照射した結果、増感比1.1と弱い増感作用を認めた。次いで、超音波による細胞周期変動作用に着目してより効果が期待できる放射線照射の時期を検討したところ、9時間後が最も効果が期待できることが明らかになった。そこで超音波照射後9時間後に放射線を照射したが、増感比は1.1と変わらなかった。平板培養系での超音波照射による細胞の剥離が原因と考えられたため、今後は3次元培養系での検討が必要と思われる。


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