滝口 満喜 (タキグチ ミツヨシ)

獣医学研究院 獣医学部門 臨床獣医科学分野教授
附属動物病院教授
One Healthリサーチセンター教授

研究者基本情報

■ 学位
  • 博士(獣医学), 北海道大学
  • 修士(獣医学), 北海道大学
■ URL
researchmap URLホームページURL■ ID 各種
J-Global ID■ 研究キーワード・分野
研究キーワード
  • 慢性炎症
  • 自己免疫疾患
  • 超音波診断
  • 画像診断
  • Veterinary Diagnostic imaging
  • Autoimmune Diseases
  • Diagnostic Ultrasound
  • Diagnostic imaging
研究分野
  • ライフサイエンス, 放射線科学
  • ライフサイエンス, 膠原病、アレルギー内科学
  • ライフサイエンス, 獣医学
■ 担当教育組織

経歴

■ 経歴
経歴
  • 2025年04月 - 現在
    北海道大学大学院獣医学研究院 教授
  • 2021年04月 - 2025年03月
    北海道大学, 大学院獣医学研究院, 大学院獣医学研究院長・獣医学部長
  • 2017年04月
    北海道大学大学院獣医学研究院, 教授
  • 2007年10月
    北海道大学, 大学院獣医学研究科, 教授
  • 2004年10月 - 2007年09月
    酪農学園大学, 獣医学部, 教授
  • 2004年06月
    北海道大学大学院獣医学研究科助教授, Graduate School of Veterinary Medicine
  • 2000年 - 2004年
    Lecturer, Graduate School of Veterinary Medicine,
  • 2004年
    - Professor, School of Veterinary Medicine, Rakuno gakuen Univ.
  • 2004年
    - Assistant Professor, Graduate School of Veterinary Medicine,
  • 2000年07月
    北海道大学大学院獣医学研究科講師, Graduate School of Veterinary Medicine
  • 1995年 - 2000年
    Instractor, Graduate School of Veterinary Medicine
  • 1996年03月 - 1996年08月
    文部省在外研究員
  • 1995年04月
    北海道大学大学院獣医学研究科助手, Graduate School of Veterinary Medicine
  • 1993年 - 1995年
    Instractor, Faculty of Veterinary Medicine, Hokkaido Univ.
  • 1993年10月
    北海道大学獣医学部助手, School of Veterinary Medicine
  • 1992年06月
    オハイオ州立大学獣医学部客員研究員
  • 1989年04月 - 1992年05月
    横浜動物医療センター
  • Hokkaiddo Univ.
学歴
  • 1987年04月 - 1989年03月, 北海道大学, 大学院獣医学研究科, (修士課程)予防治療学専攻, 日本国
  • 1983年04月 - 1987年03月, 北海道大学, 獣医学部, 獣医学科, 日本国
委員歴
  • 2023年04月 - 現在
    獣医学教育評価委員会, 副委員長, その他
  • 2014年04月 - 現在
    日本獣医学会, 理事
  • 2002年 - 現在
    日本獣医画像診断学会, 理事, 学協会
  • 2008年04月 - 2014年03月
    日本獣医学会, 評議委員
  • 2003年
    日本小動物獣医学会, 理事, 学協会
学内役職歴
  • 教育研究評議会評議員, 2019年4月1日 - 2021年3月31日
  • 教育研究評議会評議員, 2021年4月1日 - 2023年3月31日
  • 獣医学部長, 2021年4月1日 - 2023年3月31日
  • 獣医学部長, 2023年4月1日 - 2025年3月31日
  • 大学院獣医学研究院長, 2021年4月1日 - 2023年3月31日
  • 大学院獣医学研究院長, 2023年4月1日 - 2025年3月31日
  • 大学院獣医学研究院附属動物病院長, 2014年4月1日 - 2016年3月31日
  • 大学院獣医学研究院附属動物病院長, 2016年4月1日 - 2018年3月31日
  • 大学院獣医学研究院附属動物病院長, 2018年4月1日 - 2020年3月31日
  • 大学院獣医学研究院附属動物病院長, 2020年4月1日 - 2021年3月31日
  • 大学院獣医学研究院附属動物病院長, 2023年4月1日 - 2025年3月31日
  • 大学院獣医学研究院副研究院長, 2017年4月1日 - 2019年3月31日
  • 大学院獣医学研究院副研究院長, 2019年4月1日 - 2021年3月31日

研究活動情報

■ 受賞
  • 2004年, 日本小動物獣医学会北海道獣医師会長賞
    日本国
  • 1999年, 平成11年度日本小動物獣医学会(北海道)獣医師会長賞
    日本国
  • 1999年, 日本獣医学会大会長賞 獣医学奨励賞
    日本国
  • 1998年, 日本獣医学会大会長賞 獣医学奨励賞
    日本国
  • 1997年, 平成9年度日本小動物獣医学会(北海道)地区学会長賞
    日本国
■ 論文
  • Deep-learning-based automatic liver segmentation using computed tomography images in dogs
    Seungyeon Lee; Genya Shimbo; Nozomu Yokoyama; Kensuke Nakamura; Ren Togo; Takahiro Ogawa; Miki Haseyama; Mitsuyoshi Takiguchi
    Frontiers in Veterinary Science, 12, Frontiers Media SA, 2025年10月21日
    研究論文(学術雑誌), Introduction

    Deep learning-based automated segmentation has significantly improved the efficiency and accuracy of human medicine applications. However, veterinary applications, particularly canine liver segmentation, remain limited. This study aimed to develop and validate a deep learning model based on a 3D U-Net architecture for automated liver segmentation in canine abdominal computed tomography (CT) scans.

    Methods

    A total of 221 canine abdominal CT scans were analyzed, comprising 159 cases without hepatic masses and 62 cases with hepatic masses. The model was trained and evaluated using two separate datasets: one containing cases without hepatic masses (Experiment 1) and the other combining cases with and without hepatic masses (Experiment 2).

    Results

    Both experiments demonstrated high segmentation performance, achieving mean Dice similarity coefficients of 0.926 (Experiment 1) and 0.929 (Experiment 2).

    Discussion

    The manual and predicted liver volumes showed excellent agreement, highlighting the potential clinical applicability of this approach.
  • Potential human health risk of carbapenem-non-susceptible Pseudomonas aeruginosa from companion animals.
    Jirachaya Toyting-Hiraishi; Toyotaka Sato; Mana Tohyama; Taro Fujino; Kaho Okada; Kazuyoshi Sasaoka; Nozomu Yokoyama; Kana Torii; Akio Suzuki; Yuzo Tsuyuki; Kensuke Nakamura; Mitsuyoshi Takiguchi; Motohiro Horiuchi
    The Journal of antimicrobial chemotherapy, 2025年09月19日, [国際誌]
    英語, 研究論文(学術雑誌), BACKGROUND AND OBJECTIVES: The close bond between companion animals and humans may accelerate the spread of antimicrobial-resistant bacteria. Pseudomonas aeruginosa, an opportunistic pathogen in both, poses a public health threat due to antimicrobial resistance (AMR) and diverse virulence factors. However, One Health-based comparison remains limited. This study investigated the current AMR status and molecular characteristics of P. aeruginosa in companion animals in Japan to assess potential human health risks. METHODS: We examined 197 P. aeruginosa clinical isolates from companion animals [dogs (n = 99) and cats (n = 98)] across Japan in 2024. Antimicrobial susceptibility to human clinical antibiotics was evaluated. In carbapenem-non-susceptible isolates, multilocus sequence typing and detection of resistance genes and virulence factors were performed. RESULTS: Ciprofloxacin (20.3%) and piperacillin (10.7%) showed the highest resistance rates, with 5.6% of isolates being multidrug-resistant. Carbapenem resistance rates were 6.1% for imipenem and 1.0% for meropenem. Thirty-five isolates (17.8%) exhibited carbapenem non-susceptibility but remained susceptible to cefepime, ciprofloxacin, or amikacin. Of 27 identified sequence types, 20 (77.1% of carbapenem-non-susceptible isolates) were known in humans, including two high-risk clones (ST233 and ST298; 8.6%) reported for the first time in Japanese companion animals. These isolates carried mutations in efflux pump-related genes and multiple virulence factors. One showed close genetic relatedness to a human isolate, suggesting possible interspecies transmission. CONCLUSIONS: Our findings highlight the potential cross-species transmission risk of antimicrobial-resistant P. aeruginosa. Identification of shared high-risk clones with multiple virulence factors emphasizes the need for continuous vigilance and actions within the One Health framework.
  • Outcomes and Prognostic Factors in Dogs With Presumed Intracranial Gliomas Treated With Definitive-Intent Intensity Modulated Radiation Therapy: 55 Cases (2014-2023).
    Yohichi Fukuyama; Kenji Hosoya; Sangho Kim; Koangyong Sung; Tatsuya Deguchi; Genya Shimbo; Kazuyoshi Sasaoka; Ryouhei Kinoshita; Mitsuyoshi Takiguchi
    Veterinary and comparative oncology, 2025年08月25日, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), Radiation therapy (RT) is the treatment of choice for canine intracranial gliomas. Recently, modern advanced radiation techniques, including intensity modulated RT (IMRT) and volumetric modulated arc therapy (VMAT), have become widely available in veterinary medicine. However, the glioma-specific therapeutic outcomes of patients treated with modern RT remain unclear. This study aimed to describe survival outcomes and tumour response and to identify whether any treatment, clinical, and imaging factors were predictive of prognosis in dogs with intracranial gliomas treated with definitive-intent IMRT alone. Medical records of dogs with presumed intracranial gliomas that underwent definitive-intent IMRT were retrospectively reviewed. Fifty-five dogs were included. Amongst them, 29 and 26 underwent fractionated RT (FRT) and stereotactic RT (SRT), respectively. In the 44 dogs that underwent follow-up magnetic resonance imaging (MRI), the overall measurable response rate was 77.3%. Clinical improvement was observed in 92% of the dogs. Local tumour regrowth and drop metastases were observed in 17 (30.9%) and 10 dogs (18.2%), respectively. The median overall survival, disease-specific survival, and progression-free survival were 432, 670, and 441 days, respectively. Seven dogs (12.7%) died during RT or within 6 weeks. There was no statistically significant difference in the survival times between FRT and SRT. In the multivariate analysis, poor performance status, tumour location in the diencephalon, and fluid-attenuated inversion recovery heterogeneity were significantly associated with shorter survival times. These findings suggest that definitive-intent RT results in tumour shrinkage and prolonged survival (432 days) with minimal radiation toxicity regardless of the RT protocol used. Performance status and MRI findings can be useful for predicting prognosis.
  • Effects of cardiac volume loading on left atrial stiffness estimated by 2-dimensional echocardiography in healthy dogs.
    Tatsuyuki Osuga; Masahiro Tamura; Noboru Sasaki; Mitsuyoshi Takiguchi
    American journal of veterinary research, 1, 7, 2025年08月14日, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), OBJECTIVE: To elucidate the effect of cardiac volume loading, which should physiologically increase left atrial (LA) stiffness (LASt), on echocardiographically estimated LASt in healthy dogs. METHODS: 6 healthy Beagle dogs were anesthetized. In each dog, a Swan-Ganz catheter was placed to measure the mean pulmonary capillary wedge pressure. Cardiac volume loading was performed by IV infusion with hydroxyethylated starch solution. Echocardiography was transthoracically conducted at the baseline and at mean pulmonary capillary wedge pressures of 10 to 15, 15 to 20, 20 to 25, and 25 to 30 mm Hg. The echocardiographic indicators of LA pressure, including the peak velocity of early diastolic transmitral flow (E), ratio of E to the isovolumic relaxation time (E/IVRT), ratio of E to the peak velocity of early diastolic mitral annular motion (E/E'), and LA reservoir strain, were determined to estimate LASt. RESULTS: During cardiac volume loading, E, E/IVRT, and LA reservoir strain were increased, and E/E' was decreased, when compared with the baseline. Consequently, LASts estimated by using E, E/IVRT, and E/E' were decreased or remained unchanged during cardiac volume loading. CONCLUSIONS: Echocardiographically estimated LASt may not be increased by cardiac volume loading in healthy dogs. CLINICAL RELEVANCE: Healthy dogs may not be an appropriate model to elucidate the effect of cardiac volume loading on echocardiographically estimated LASt. This is problematic, especially for dogs with myxomatous mitral valve disease that are older and may have cardiac dysfunction.
  • Ultrasonographic features and blood biochemistry findings of cholangiocarcinoma in a captive polar bear (Ursus maritimus)
    Keita Kakisaka; Nozomu Yokoyama; Fuka Takahashi; Keisuke Aoshima; Mitsuyoshi Takiguchi
    Veterinary Record Case Reports, Wiley, 2025年06月28日
    研究論文(学術雑誌), ABSTRACT

    A 29‐year‐old male captive polar bear (Ursus maritimus) with a year‐long history of elevated gamma‐glutamyl transpeptidase (GGT) presented with a 2‐week history of anorexia and abdominal distention. Blood biochemistry revealed a severely elevated GGT (>1500 IU/L). Abdominal ultrasound revealed multiple cystic hepatic masses and marked ascites. Fourteen days after initial presentation, the patient was found dead. Postmortem examination revealed hepatomegaly with diffuse, multifocal, coalescing cysts containing a red‒tan to dark‐red serous fluid. Histopathologically, the cyst walls were lined by flattened or cuboidal neoplastic cells, some exhibiting tubulopapillary projections into the lumen. Metastatic lesions were identified in the anterior mediastinal lymph nodes, lungs and kidneys. This case was diagnosed as cholangiocarcinoma. While there are numerous reports of cholangiocarcinoma in polar bears, published data on blood biochemistry and abdominal ultrasonographic findings are limited. This case report illustrates the benefit of blood biochemistry and abdominal ultrasound in investigating cholangiocarcinoma in polar bears.
  • Evaluation of the course of improvement with molnupiravir treatment for feline infectious peritonitis.
    Shino Yoshida; Mei Sugawara-Suda; Kazuyoshi Sasaoka; Noboru Sasaki; Nozomu Yokoyama; Kensuke Nakamura; Keitaro Morishita; Sangho Kim; Takafumi Sunaga; Mitsuyoshi Takiguchi
    The Canadian veterinary journal = La revue veterinaire canadienne, 66, 5, 546, 554, 2025年05月, [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), OBJECTIVE: To clarify the clinical course during molnupiravir treatment for feline infectious peritonitis (FIP). ANIMALS AND PROCEDURE: Cats diagnosed with FIP and treated with molnupiravir at Hokkaido University Veterinary Teaching Hospital (Sapporo, Hokkaido, Japan) were retrospectively reviewed. RESULTS: Eleven cats were eligible for inclusion. Six cats had effusive FIP and 5 had non-effusive FIP. In noneffusive cases, 2 cats had neurological abnormalities at diagnosis, whereas 1 additional cat developed neurological signs during treatment. The median initial dosage of molnupiravir was 13.0 mg/kg (range: 10.0 to 15.0 mg/kg), PO, q12h. One cat died after 11 d and the remaining 10 cats completed an 84-day course of treatment. All neurological cases were given dosage increases, extended treatment duration, or both. The median final dosage of molnupiravir in non-neuro-FIP cases was 13.1 mg/kg (range: 10.0 to 15.0 mg/kg), PO, q12h, whereas dosages in neuro-FIP cases were 15.0, 15.2, and 17.2 mg/kg, PO, q12h in the 3 affected cats, respectively. In non-neurological cases, dysrexia, lethargy, and high serum amyloid A were resolved within 15 d. Total follow-up duration ranged from 175 to 362 d. No relapses were observed. CONCLUSION AND CLINICAL RELEVANCE: Monitoring responses to molnupiravir treatment requires observing clinical signs and conducting clinicopathological evaluations, including acute-phase protein evaluation.
  • Pre-operative left atrial size and functions are predictors of left atrial reverse remodelling after mitral valvuloplasty for myxomatous mitral valve disease in dogs.
    S Kawamoto; K Nakamura; T Mori; T Wada; A Fujiwara; M Takiguchi
    Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 57, 47, 57, 2025年02月, [国際誌]
    英語, 研究論文(学術雑誌), OBJECTIVES: The objective of this study was to determine alterations in left atrial size, function, and determinants of left atrial reverse remodelling (LARR) after mitral valvuloplasty (MVP) in dogs with myxomatous mitral valve disease. ANIMALS: Thirty-seven dogs undergoing MVP were included in this study. MATERIALS AND METHODS: Echocardiographic parameters, including left atrial (LA) strain, were evaluated at baseline, during the early postoperative period (within two weeks), and at one and three months postoperatively. Patients were divided into two groups based on the attainment of LARR, defined as a left atrial-to-aortic root ratio (LA:Ao) < 1.6 at three months. The predictors of LARR were analysed using univariate logistic regression analysis. RESULTS: Left atrial-to-aortic root ratio significantly decreased in the early postoperative period (median: 1.68; lower and upper quartiles: 1.54-1.92) compared to that in baseline (2.41; 2.00-2.80), with a further significant reduction observed at three months (1.46; 1.34-1.63). Left atrial reverse remodelling was achieved in 27 (73%) patients. Baseline left atrial-to-aortic root ratio was higher, and peak atrial longitudinal strain and peak atrial contraction strain (PACS) were lower in the non-LARR group than in the LARR group. Among the baseline parameters, PACS was the strongest predictor of LARR (area under the curve: 0.837). CONCLUSIONS: Following MVP, the LA size decreased in the early postoperative period and continued to decrease over three months of follow-up. A low PACS score was the most reliable predictor of inadequate LARR. Further studies are necessary to determine the relationship between LARR, prognosis, and the optimal timing for surgical intervention.
  • Reference intervals for urinary metanephrines to creatinine ratios in dogs in Japan.
    Noriyuki Nagata; Yoshinori Ikenaka; Hiryu Sawamura; Noboru Sasaki; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 2024年09月03日, [査読有り], [最終著者, 責任著者], [国内誌]
    英語, 研究論文(学術雑誌), The urinary normetanephrine to creatinine ratio (uNMN/Cr) and urinary metanephrine to creatinine ratio (uMN/Cr) are commonly evaluated for the diagnosis of pheochromocytomas (PCC) in dogs. This study aimed to establish reference intervals for uNMN/Cr and uMN/Cr in 56 healthy dogs in Japan and to investigate the effect of urine collection methods on these measurements in 15 non-PCC dogs. The upper limits of reference intervals for uNMN/Cr and uMN/Cr were 124.4 nmol/mmol (90% confidence interval [CI] 107.7-137.0) and 121.1 nmol/mmol (90% CI 102.8-145.1), respectively. Both uNMN/Cr and uMN/Cr were significantly higher when urine was collected in the hospital compared to at home. Several factors, including the method of urine collection, should be considered when utilizing these reference intervals.
  • Case report: Echinococcus multilocularis infection in a dog showing gastrointestinal signs in Hokkaido, Japan
    Izumi Kida; Naoki Hayashi; Nozomu Yokoyama; Noriyuki Nagata; Kazuyoshi Sasaoka; Noboru Sasaki; Keitaro Morishita; Kensuke Nakamura; Hirokazu Kouguchi; Kinpei Yagi; Ryo Nakao; Mitsuyoshi Takiguchi; Nariaki Nonaka
    Frontiers in Veterinary Science, 11, Frontiers Media SA, 2024年06月13日, [査読有り]
    英語, 研究論文(学術雑誌), Echinococcus multilocularis is a cestode that causes human alveolar echinococcosis, a lethal zoonotic disease distributed in the northern hemisphere. The life cycle of this parasite is maintained in nature by voles as intermediate hosts and foxes as definitive hosts in Hokkaido, Japan. Although dogs are also susceptible to the parasite, the infection has been considered typically asymptomatic. We report the detection of E. multilocularis eggs in the diarrheal feces of a dog with chronic gastrointestinal signs, which disappeared after anthelmintic treatment. The mitochondrial genome sequence constructed by sequencing of the overlapping PCRs using DNA from the eggs was identical to the most predominant haplotype previously reported in red foxes in Hokkaido. This case highlights that Echinococcus infection should be considered as a differential diagnosis for diarrheal dogs in the disease endemic areas. Further efforts are needed to accumulate parasite genotypes in domestic dogs as well as humans to assess the risk of human infection from dogs.
  • Urinary steroid profiling using liquid chromatography-tandem mass spectrometry for the diagnosis of canine Cushing's syndrome.
    N Nagata; H Sawamura; Y Ikenaka; K Morishita; K Hosoya; N Sasaki; K Nakamura; M Takiguchi
    Veterinary journal (London, England : 1997), 106151, 106151, 2024年05月29日, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), Serum cortisol measurements by chemiluminescence enzyme immunoassay (CLEIA) are widely used to diagnose hypercortisolism (HC) or Cushing's syndrome in dogs. However, they are associated with problems such as the need for multiple blood collections under stressful conditions or cross-reactivity between hormones. Therefore, a less invasive and more accurate diagnostic method is required. This study aimed to develop a urinary steroid profile analysis method using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and to evaluate its clinical usefulness. Sixty-five healthy dogs and 38 dogs with suspected HC were included in the study. Using LC/MS/MS, the levels of 11 steroid hormones in the urine were determined. We established the upper limit of the reference interval for each urinary steroid-to-creatinine ratio and evaluated their diagnostic performances. The levels of the five steroid hormones were significantly higher in the 14 dogs with HC than in the 24 dogs with mimicking HC and 65 healthy dogs. The urinary corticosterone-to-creatinine ratio showed the highest diagnostic accuracy (area under the curve, 0.96). A significant correlation was seen between urinary cortisol concentrations measured by LC/MS/MS and CLEIA (rs = 0.88, P <0.001), although the CLEIA measurements were significantly higher than the LC/MS/MS measurements (P <0.001). LC/MS/MS-based urinary steroid profiles are a promising tool for diagnosing canine HC.
  • Antimicrobial resistance and self-reported hand hygiene awareness before and after an infection prevention and control programme: a 7-year analysis in a small animal veterinary teaching hospital
    K. Sasaoka; T. Sato; K. Morishita; K. Hosoya; N. Yokoyama; T. Sato; M. Horiuchi; M. Takiguchi
    The Veterinary Journal, 106154, 106154, Elsevier BV, 2024年05月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌)
  • A de novo nonsense variant in the DMD gene associated with X-linked dystrophin-deficient muscular dystrophy in a cat.
    Nozomu Yokoyama; Yuki Matsumoto; Takahisa Yamaguchi; Kazuki Okada; Ryohei Kinoshita; Genya Shimbo; Hisashi Ukawa; Ryuga Ishii; Kensuke Nakamura; Jumpei Yamazaki; Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine, 2024年04月13日, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), BACKGROUND: X-linked dystrophin-deficient muscular dystrophy (MD) is a form of MD caused by variants in the DMD gene. It is a fatal disease characterized by progressive weakness and degeneration of skeletal muscles. HYPOTHESIS/OBJECTIVES: Identify deleterious genetic variants in DMD by whole-genome sequencing (WGS) using a next-generation sequencer. ANIMALS: One MD-affected cat, its parents, and 354 cats from a breeding colony. METHODS: We compared the WGS data of the affected cat with data available in the National Center for Biotechnology Information database and searched for candidate high-impact variants by in silico analyses. Next, we confirmed the candidate variants by Sanger sequencing using samples from the parents and cats from the breeding colony. We used 2 genome assemblies, the standard felCat9 (from an Abyssinian cat) and the novel AnAms1.0 (from an American Shorthair cat), to evaluate genome assembly differences. RESULTS: We found 2 novel high-impact variants: a 1-bp deletion in felCat9 and an identical nonsense variant in felCat9 and AnAms1.0. Whole genome and Sanger sequencing validation showed that the deletion in felCat9 was a false positive because of misassembly. Among the 357 cats, the nonsense variant was only found in the affected cat, which indicated it was a de novo variant. CONCLUSION AND CLINICAL IMPORTANCE: We identified a de novo variant in the affected cat and next-generation sequencing-based genotyping of the whole DMD gene was determined to be necessary for affected cats because the parents of the affected cat did not have the risk variant.
  • Interventricular inflow time difference assessed by dual pulsed-wave Doppler echocardiography in dogs with myxomatous mitral valve disease
    T. Morita; K. Nakamura; T. Osuga; S. Kawamoto; M. Takiguchi
    Journal of Veterinary Cardiology, 51, 24, 34, Elsevier BV, 2024年02月, [査読有り], [最終著者]
    英語, 研究論文(学術雑誌)
  • Use of genome-wide DNA methylation analysis to identify prognostic CpG site markers associated with longer survival time in dogs with multicentric high-grade B-cell lymphoma.
    Yong Bin Teoh; Teita Ishizaki; Yumiko Kagawa; Shoko Yokoyama; Jaroslav Jelinek; Yuki Matsumoto; Hirotaka Tomiyasu; Hajime Tsujimoto; Mitsuyoshi Takiguchi; Jumpei Yamazaki
    Journal of veterinary internal medicine, 38, 1, 316, 325, 2024年, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), BACKGROUND: DNA methylation analysis might identify prognostic CpG sites in CHOP-treated dogs with multicentric high-grade B-cell lymphoma (MHGL) with heterogenous prognosis. OBJECTIVE: To identify prognostic CpG sites of MHGL through genome-wide DNA methylation analysis with pyrosequencing validation. ANIMALS: Test group: 24 dogs. Validation group: 100 dogs. All client-owned dogs were diagnosed with MHGL and treated with CHOP chemotherapy. METHODS: Cohort study. DNA was extracted from lymph node samples obtained via FNA. Genome-wide DNA methylation analysis using Digital Restriction Enzyme Analysis of Methylation (DREAM) was performed on the test group to identify differentially methylated CpG sites (DMCs). Bisulfite pyrosequencing was used to measure methylation status of candidate DMCs in the validation group. Median survival times (MST) were analyzed using Kaplan-Meier (log-rank) product limit method. RESULTS: DREAM analyzed 101 576 CpG sites. Hierarchical clustering of 16 262 CpG sites in test group identified group with better prognosis (MST = 55-477 days vs 10-301 days, P = .007). Volcano plot identified 1371 differentially methylated CpG sites (DMCs). DMC near the genes of FAM213A (DMC-F) and PHLPP1 (DMC-P) were selected as candidates. Bisulfite-pyrosequencing performed on validation group showed group with methylation level of DMC-F < 40% had favorable prognosis (MST = 11-1072 days vs 8-1792 days, P = .01), whereas group with the methylation level combination of DMC-F < 40% plus DMC-P < 10% had excellent prognosis (MST = 18-1072 days vs 8-1792 days, P = .009). CONCLUSION AND CLINICAL IMPORTANCE: Methylation status of prognostic CpG sites delineate canine MGHL cases with longer MST, providing owners with information on expectations of potential improved treatment outcomes.
  • Adrenocortical hypoperfusion detected by contrast-enhanced ultrasound in a dog with trilostane-induced hypoadrenocorticism.
    N Nagata; K Aoshima; K Nakamura; M Takiguchi
    The Journal of small animal practice, 64, 11, 722, 726, 2023年11月, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, A 12-year-old neutered male Chihuahua dog was diagnosed with pituitary-dependent hypercortisolism and treated with trilostane. Eighty-nine days later, the dog showed lethargy accompanied by hyponatraemia and hyperkalaemia. Hypoadrenocorticism due to trilostane was suspected, but the result of the adrenocorticotropic hormone stimulation test was not conclusive. Contrast-enhanced ultrasound showed loss of adrenocortical blood flow in both adrenal glands, indicating adrenocortical hypoperfusion and isolated hypoadrenocorticism. Treatment with fludrocortisone acetate improved the condition and electrolyte abnormalities. Thirteen months later, the dog showed alopecia, and an adrenocorticotropic hormone stimulation test revealed increased cortisol concentration, indicating hypercortisolism recurrence. The dog died due to progressive deterioration 22 months after the initial presentation. Post-mortem examination revealed focally extensive necrosis with marked calcification in the parenchyma of the adrenal glands and regeneration of the cells in the zona fasciculata with severe fibrosis. Adrenocortical hypoperfusion detected by contrast-enhanced ultrasound can support the diagnosis of adrenal necrosis and hypoadrenocorticism.
  • The role of heat shock protein 90 in the proliferation of Babesia gibsoni in vitro.
    Hiroka Tsutsumi; Moeko Abe; Naohiro Uchida; Mitsuyoshi Takiguchi; Masahiro Yamasaki
    Experimental parasitology, 251, 108567, 108567, 2023年08月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), The present study investigated the role of heat shock protein 90 (HSP90) in the proliferation and survival of Babesia gibsoni in vitro. To detect the effect on the entry of B. gibsoni into host erythrocytes, the parasite was incubated with an antibody against B. gibsoni HSP90 (BgHSP90) for 24 h. The results of this experiment demonstrated that both the incorporation of [3H]hypoxanthine into the nucleic acids of B. gibsoni and the number of parasites were not altered, indicating that an anti-BgHSP90 antibody did not directly inhibit the entry of the parasite into erythrocytes. Moreover, two HSP90 inhibitors, geldanamycin (GA) and tanespimycin (17-AAG), were used to evaluate the function of BgHSP90. GA and 17-AAG decreased both the incorporation of [3H]hypoxanthine and the number of infected erythrocytes, suggesting that BgHSP90 plays important roles in DNA synthesis and the proliferation of B. gibsoni. The effect of 17-AAG on the parasites was weaker than that of GA. Additionally, the effect of GA on the survival and superoxide generation of canine neutrophils was assessed. The survival of canine neutrophils was not affected. The superoxide generation was strongly suppressed by GA. This result indicated that GA inhibited the function of canine neutrophils. Additional studies are necessary to elucidate the role of BgHSP90 in the proliferation of the parasite.
  • Diverse genome-wide DNA methylation alterations in canine hepatocellular tumours.
    Yu Asari; Jumpei Yamazaki; Oo Thandar; Tamami Suzuki; Keisuke Aoshima; Kyosuke Takeuchi; Ryohei Kinoshita; Sangho Kim; Kenji Hosoya; Teita Ishizaki; Yumiko Kagawa; Jaroslav Jelinek; Shoko Yokoyama; Noboru Sasaki; Hiroshi Ohta; Kensuke Nakamura; Mitsuyoshi Takiguchi
    Veterinary medicine and science, 2023年07月22日, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), BACKGROUND: Canine hepatocellular tumours (HCTs) are common primary liver tumours. However, the exact mechanisms of tumourigenesis remain unclear. Although some genetic mutations have been reported, DNA methylation alterations in canine HCT have not been well studied. OBJECTIVES: In this study, we aimed to analyse the DNA methylation status of canine HCT. METHODS: Tissues from 33 hepatocellular carcinomas, 3 hepatocellular adenomas, 1 nodular hyperplasia, 21 non-tumour livers from the patients and normal livers from 5 healthy dogs were used. We analysed the DNA methylation levels of 72,367 cytosine-guanine dinucleotides (CpG sites) in all 63 samples. RESULTS AND CONCLUSIONS: Although a large fraction of CpG sites that were highly methylated in the normal liver became hypomethylated in tumours from most patients, we also found some patients with less remarkable change or no change in DNA methylation. Hierarchical clustering analysis revealed that 32 of 37 tumour samples differed from normal livers, although the remaining 5 tumour livers fell into the same cluster as normal livers. In addition, the number of hypermethylated genes in tumour livers varied among tumour cases, suggesting various DNA methylation patterns in different tumour groups. However, patient and clinical parameters, such as age, were not associated with DNA methylation status. In conclusion, we found that HCTs undergo aberrant and diverse patterns of genome-wide DNA methylation compared with normal liver tissue, suggesting a complex epigenetic mechanism in canine HCT.
  • An inflammatory bowel disease-associated SNP increases local thyroglobulin expression to develop inflammation in miniature dachshunds
    Yong Bin Teoh; Jing-Jing Jiang; Takeshi Yamasaki; Noriyuki Nagata; Toshiki Sugawara; Rie Hasebe; Hiroshi Ohta; Noboru Sasaki; Nozomu Yokoyama; Kensuke Nakamura; Yumiko Kagawa; Mitsuyoshi Takiguchi; Masaaki Murakami
    Frontiers in Veterinary Science, 10, Frontiers Media SA, 2023年07月14日, [査読有り], [責任著者]
    英語, 研究論文(学術雑誌), Inflammatory colorectal polyp (ICRP) in miniature dachshunds (MDs) is a chronic inflammatory bowel disease (IBD) characterized by granulomatous inflammation that consists of neutrophil infiltration and goblet cell hyperplasia in the colon. Recently, we identified five MD-associated single-nucleotide polymorphisms (SNPs), namely PLG, TCOF1, TG, COL9A2, and COL4A4, by whole-exome sequencing. Here, we investigated whether TG c.4567C&gt;T (p.R1523W) is associated with the ICRP pathology. We found that the frequency of the T/T SNP risk allele was significantly increased in MDs with ICRP. In vitro experiments showed that TG expression in non-immune cells was increased by inducing the IL-6 amplifier with IL-6 and TNF-α. On the other hand, a deficiency of TG suppressed the IL-6 amplifier. Moreover, recombinant TG treatment enhanced the activation of the IL-6 amplifier, suggesting that TG is both a positive regulator and a target of the IL-6 amplifier. We also found that TG expression together with two NF-κB targets, IL6 and CCL2, was increased in colon samples isolated from MDs with the T/T risk allele compared to those with the C/C non-risk allele, but serum TG was not increased. Cumulatively, these results suggest that the T/T SNP is an expression quantitative trait locus (eQTL) of TG mRNA in the colon, and local TG expression triggered by this SNP increases the risk of ICRP in MDs via the IL-6 amplifier. Therefore, TG c.4567C&gt;T is a diagnostic target for ICRP in MDs, and TG-mediated IL-6 amplifier activation in the colon is a possible therapeutic target for ICRP.
  • Successful treatment of sclerosing encapsulating peritonitis in a cat using bioresorbable hyaluronate-carboxymethylcellulose membrane after surgical adhesiolysis and long-term prednisolone
    Nozomu Yokoyama; Ryohei Kinoshita; Hiroshi Ohta; Kazuki Okada; Genya Shimbo; Kazuyoshi Sasaoka; Noriyuki Nagata; Noboru Sasaki; Keitaro Morishita; Kensuke Nakamura; Yumiko Kagawa; Mitsuyoshi Takiguchi
    Journal of Feline Medicine and Surgery Open Reports, 9, 2, SAGE Publications, 2023年07月, [査読有り], [最終著者, 責任著者]
    研究論文(学術雑誌), Case summary

    An 8-year-old neutered male domestic shorthair indoor cat was presented with an 8-week history of intermittent vomiting, anorexia and weight loss that had been unresponsive to supportive treatment. Abdominal ultrasound revealed plication of the small intestine and fluid accumulation proximal to the lesion, and a linear foreign body was suspected. An exploratory celiotomy showed cocoon-like encapsulation of the entire intestine. Surgical adhesiolysis and full-thickness biopsy were performed, and histopathologic examination revealed mild thickening of the visceral peritoneum with fibrin deposition, as well as mild neutrophil and lymphocyte infiltration. These findings were compatible with sclerosing encapsulating peritonitis (SEP). The cat recovered well postoperatively and was discharged the next day. Prednisolone was administered for 7 weeks to prevent recurrence of SEP. Five months after surgery, the cat was re-presented with anorexia and chronic vomiting. Based on the clinical examination findings, recurrent SEP was suspected. At the second surgery, surgical adhesiolysis was repeated and a bioresorbable hyaluronate-carboxymethylcellulose membrane was used to cover the serosal surface and thus prevent adhesion formation. Histopathologic findings of the peritoneal biopsy specimen confirmed SEP. Long-term prednisolone treatment (1 mg/kg for the first dose and 0.5 mg/kg every 48 h for maintenance) was administered postoperatively. The cat survived for more than 1239 days without recurrence.

    Relevance and novel information

    To our knowledge, this is the first report of SEP in a cat with long-term survival. The use of a bioresorbable hyaluronate-carboxymethylcellulose membrane and long-term prednisolone treatment may have prevented short-term and long-term recurrence, respectively, in this case.
  • Investigation of the therapeutic effects, predictors, and complications of long-term immunosuppressive therapy in dogs with precursor-targeted immune-mediated anemia.
    Mei Sugawara-Suda; Keitaro Morishita; Yuto Iwanaga; Jumpei Yamazaki; Yumiko Kagawa; Nozomu Yokoyama; Noboru Sasaki; Hiroshi Ohta; Kensuke Nakamura; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 85, 7, 695, 701, 2023年07月01日, [査読有り], [最終著者], [国内誌]
    英語, 研究論文(学術雑誌), Dogs with precursor-targeted immune-mediated anemia (PIMA) are commonly treated with immunosuppressive therapy, but information on predictors of treatment response and response time is limited. Therefore, we retrospectively investigated predictive factors that influenced the treatment response and duration required to observe a response in dogs with PIMA receiving continuous immunosuppressive therapies for more than 105 days. Of 50 client-owned dogs that developed PIMA, 27 were included in this study, of which 18 were responders and 9 were non-responders to immunosuppressive therapies. Sixteen of the 18 responders responded to treatment within 60 days and the remaining 2 responded at 93 and 126 days, respectively. We found that an erythroid-maturation ratio of <0.17 may be a useful predictor for treatment response. In addition, complications of immunosuppressive therapies were investigated further in 50 dogs. Pancreatitis (n=4) and pneumonia (3) occurred over the entire treatment period, and infections such as abscesses (3) tended to be more common in dogs on an extended period of immunosuppressive therapy. These findings may be helpful when planning for the initial treatment and may provide evidence for informed consent about potential comorbidities throughout the treatment course.
  • Effectiveness of 2‐dimensional shear wave elastography for noninvasive and reliable estimation of right atrial pressure in dogs with induced volume overload
    Masahiro Tamura; Hiroshi Ohta; Tatsuyuki Osuga; Mitsuyoshi Takiguchi
    Journal of Veterinary Internal Medicine, Wiley, 2023年04月10日, [査読有り], [責任著者]
    研究論文(学術雑誌)
  • Evaluation of responses to immunosuppressive therapy in dogs with suspected non‐regenerative immune‐mediated anaemia: 11 cases (2012‐2018)
    K. Morishita; M. Sugawara‐Suda; J. Yamazaki; N. Sasaki; K. Nakamura; H. Ohta; M. Takiguchi
    Journal of Small Animal Practice, 64, 527, Wiley, 2023年04月07日, [査読有り], [最終著者]
    英語, 研究論文(学術雑誌)
  • Zoobiquity experiments show the importance of the local MMP9-plasminogen axis in inflammatory bowel diseases in both dogs and patients.
    Takeshi Yamasaki; Noriyuki Nagata; Toru Atsumi; Rie Hasebe; Yuki Tanaka; Izuru Ohki; Shimpei Kubota; Yuta Shinohara; Yong Bin Teoh; Nozomu Yokoyama; Noboru Sasaki; Kensuke Nakamura; Hiroshi Ohta; Takehiko Katsurada; Yoshihiro Matsuno; Shintaro Hojyo; Shigeru Hashimoto; Mitsuyoshi Takiguchi; Masaaki Murakami
    International immunology, 35, 7, 313, 326, 2023年03月18日, [査読有り], [責任著者], [国際誌]
    英語, 研究論文(学術雑誌), Using a zoobiquity concept, we directly connect animal phenotypes to a human disease mechanism: the reduction of local plasminogen levels caused by matrix metalloproteinase-9 (MMP9) activity is associated with the development of inflammation in the intestines of dogs and patients with inflammatory bowel disease. We first investigated inflammatory colorectal polyps (ICRPs), which are a canine gastrointestinal disease characterized by the presence of idiopathic chronic inflammation, in Miniature Dachshund (MD), and found 31 missense disease-associated SNPs by whole-exome sequencing. We sequenced them in 10 other dog breeds and found five, PLG, TCOF1, TG, COL9A2, and COL4A4, only in MD. We then investigated two rare and breed-specific missense SNPs (T/T SNPs), PLG: c.477G>T and c.478A>T, and found that ICRPs with the T/T SNP risk-alleles showed less intact plasminogen and plasmin activity in the lesions compared to ICRPs without the risk-alleles but no differences in serum. Moreover, we show that MMP9, which is a NF-κB target, caused the plasminogen reduction and that intestinal epithelial cells expressing plasminogen molecules were colocalized with epithelial cells expressing MMP9 in normal colons with the risk-alleles. Importantly, MMP9 expression in patients with ulcerous colitis or Crohn's disease also colocalized with epithelial cells showing enhanced NF-κB activation and less plasminogen expression. Overall, our zoobiquity experiments showed that MMP9 induces the plasminogen reduction in intestine, contributing to the development of local inflammation and suggesting the local MMP9-plasminogen axis is a therapeutic target in both dogs and patients. Therefore, zoobiquity-type experiments could bring new perspectives for biomarkers and therapeutic targets.
  • Prognostic value of left atrial stiffness estimated using echocardiography in dogs with myxomatous mitral valve disease
    T. Osuga; K. Kuroda; T. Morita; N. Sasaki; K. Nakamura; M. Takiguchi
    Journal of Veterinary Cardiology, 45, 15, 26, 2023年02月, [査読有り], [最終著者, 責任著者]
    研究論文(学術雑誌)
  • Transcriptome and proteome analysis of dogs with precursor targeted immune-mediated anemia treated with splenectomy.
    Mei Sugawara-Suda; Keitaro Morishita; Osamu Ichii; Takashi Namba; Keisuke Aoshima; Yumiko Kagawa; Sangho Kim; Kenji Hosoya; Nozomu Yokoyama; Noboru Sasaki; Kensuke Nakamura; Jumpei Yamazaki; Mitsuyoshi Takiguchi
    PloS one, 18, 5, e0285415, 2023年, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), Precursor-targeted immune-mediated anemia (PIMA) in dogs is characterized by persistent non-regenerative anemia and ineffective erythropoiesis, and it is suspected to be an immune-mediated disease. Most affected dogs respond to immunosuppressive therapies; however, some are resistant. In this study, we carried out splenectomy as an alternative therapy for refractory PIMA in dogs, and analyzed gene expression levels in the spleen of dogs with or without PIMA and in serum before and after splenectomy. A total of 1,385 genes were found to express differentially in the spleens from dogs with PIMA compared with healthy dogs by transcriptome analysis, of which 707 genes were up-regulated, including S100A12, S100A8, and S100A9 that are linked directly to the innate immune system and have been characterized as endogenous damage-associated molecular patterns. Furthermore, immunohistochemistry confirmed that S100A8/A9 protein expression levels were significantly higher in dogs with PIMA compared with those in healthy dogs. A total of 22 proteins were found to express differentially between the serum samples collected before and after splenectomy by proteome analysis, of which 12 proteins were up-regulated in the samples before. The lectin pathway of complement activation was identified by pathway analysis in pre-splenectomy samples. We speculated that S100A8/9 expression may be increased in the spleen of dogs with PIMA, resulting in activation of the lectin pathway before splenectomy. These findings further our understanding of the pathology and mechanisms of splenectomy for PIMA.
  • Biological effects related to exposure to polychlorinated biphenyl (PCB) and decabromodiphenyl ether (BDE-209) on cats
    Khidkhan K; Mizukawa H; Ikenaka Y; Nakayama SMM; Nomiyama K; Yokoyama N; Ichii O; Takiguchi M; Tanabe S; Ishizuka M
    PLOS ONE, 18, 1, e0277689, 2023年01月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), As an animal familiar to humans, cats are considered to be sensitive to chemicals; cats may be exposed to polychlorinated biphenyls (PCBs) and decabromodiphenyl ether (BDE-209) from indoor dust, household products, and common pet food, leading to adverse endocrine effects, such as thyroid hormone dysfunction. To elucidate the general biological effects resulting from exposure of cats to PCBs and PBDEs, cats were treated with a single i.p. dose of a principal mixture of 12 PCBs and observed for a short-term period. Results revealed that the testis weight, serum albumin, and total protein of the treated group decrease statistically in comparison with those in the control group. The negative correlations suggested that the decrease in the total protein and albumin levels may be disturbed by 4'OH-CB18, 3'OH-CB28 and 3OH-CB101. Meanwhile, the serum albumin level and relative brain weight decreased significantly for cats subjected to 1-year continuous oral administration of BDE-209 in comparison to those of control cats. In addition, the subcutaneous fat as well as serum high-density lipoprotein (HDL) and triglycerides (TG) levels increased in cats treated with BDE-209 and down-regulation of stearoyl-CoA desaturase mRNA expression in the liver occurred. These results suggested that chronic BDE-209 treatment may restrain lipolysis in the liver, which is associated with lipogenesis in the subcutaneous fat. Evidence of liver and kidney cell damage was not observed as there was no significant difference in the liver enzymes, blood urea nitrogen and creatinine levels between the two groups of both experiments. To the best of our knowledge, this is the first study that provides information on the biochemical effects of organohalogen compounds in cats. Further investigations on risk assessment and other potential health effects of PCBs and PBDEs on the reproductive system, brain, and lipid metabolism in cats are required.
  • An experimental challenge model for Leishmania donovani in beagle dogs, showing a similar pattern of parasite burden in the peripheral blood and liver.
    Hiroya Konno; Nozomu Yokoyama; Yu Tamura; Keisuke Aoshima; Ryo Nakao; Mitsuyoshi Takiguchi; Ken Katakura
    Parasitology research, 121, 12, 3569, 3579, 2022年12月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Leishmania donovani and Leishmania infantum are closely related species. However, the former is considered the causative agent for anthroponotic visceral leishmaniasis (AVL), while the latter is known to be responsible for zoonotic visceral leishmaniasis (ZVL) with dogs as the main reservoir host. Although molecular detection of L. donovani from naturally infected dogs has been reported in AVL endemic areas, the experimental infection of dogs with this species is very limited. Here, we constructed an experimental canine visceral leishmaniasis (CVL) model with L. donovani infection using beagle dogs. During an observation period of 8 months after parasite inoculation, few clinical symptoms were observed in the three inoculated dogs. The overall hematological and biochemical data of the dogs showed normal levels, and there were no remarkable changes in the peripheral CD4+, CD8+, CD25+, or FoxP3+ T cell populations. Liver biopsy sampling was conducted to monitor the parasite burden in the liver. A similar pattern of the amount of mitochondrial kinetoplast DNA was observed in the peripheral blood and liver by real-time PCR analysis. In addition, parasite antigens were detected from the liver biopsy sections by immunohistochemical analysis, further supporting the existence of parasites in the liver. These results showed a subclinical CVL model for L. donovani in beagle dogs with a similar kinetics of parasite burden in the peripheral blood and liver.
  • Health impact assessment of pet cats caused by organohalogen contaminants by serum metabolomics and thyroid hormone analysis.
    Kei Nomiyama; Yasuo Yamamoto; Akifumi Eguchi; Hiroyuki Nishikawa; Hazuki Mizukawa; Nozomu Yokoyama; Osamu Ichii; Mitsuyoshi Takiguchi; Shouta M M Nakayama; Yoshinori Ikenaka; Mayumi Ishizuka
    The Science of the total environment, 842, 156490, 156490, 2022年10月10日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Companion animals are in close contact with the human surroundings, and there is growing concern about the effects of harmful substances on the health of pet cats. In this study, we investigated the potential health effects of organohalogen compounds (OHCs) on thyroid hormone (TH) homeostasis and metabolomics in Japanese pet cats. There was a significant negative correlation between concentrations of several contaminants, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hydroxylated PCBs (OH-PCBs), hydroxylated PBDEs (OH-PBDEs), and THs in cat serum samples. These results suggested that exposure to OHCs causes a decrease in serum TH levels in pet cats. In this metabolomics study, each exposure level of parent compounds (PCBs and PBDEs) and their hydroxylated compounds (OH-PCBs and OH-PBDEs) were associated with their own unique primary metabolic pathways, suggesting that parent and phenolic compounds exhibit different mechanisms of action and biological effects. PCBs were associated with many metabolic pathways, including glutathione and purine metabolism, and the effects were replicated in in-vivo cat PCB administration studies. These results demonstrated that OHC exposure causes chronic oxidative stress in pet cats. PBDEs were positively associated with alanine, aspartate, and glutamate metabolism. Due to the chronic exposure of cats to mixtures of these contaminants, the combination of their respective metabolic pathways may have a synergistic effect.
  • Local cerebral blood flow assessment using transcranial Doppler ultrasonography in a dog with brain infarction in the right middle cerebral artery territory.
    Kazuyoshi Sasaoka; Hiroshi Ohta; Tomohito Ishizuka; Tatsuyuki Osuga; Keitaro Morishita; Noboru Sasaki; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 84, 10, 1385, 1390, 2022年10月01日, [査読有り], [最終著者, 責任著者], [国内誌]
    英語, 研究論文(学術雑誌), A 12-year-old neutered male Chihuahua was diagnosed with acute brain infarction in the right middle cerebral artery (MCA) territory. Transcranial Doppler ultrasonography (TCD) was performed to assess the local cerebral blood flow at the time of diagnosis and after 4 and 31 hr. Initially, the right MCA retained blood flow but with a lower cerebral blood flow velocity (CBFV; 14.9 cm/sec) than the left MCA (27.9 cm/sec). The TCD vascular resistance variables were higher in the right than in the left MCA. An increase in the CBFV and a decrease in TCD vascular resistance variables were observed, consistent with improvements in neurological symptoms. TCD can be a non-invasive, and easy-to-use modality for bedside monitoring of cerebral edema and infarction.
  • Malignant oligoastrocytoma in the spinal cord of a cat.
    Dai Hasegawa; Keisuke Aoshima; Kazuyoshi Sasaoka; Atsushi Kobayashi; Mitsuyoshi Takiguchi; Takashi Kimura
    The Journal of veterinary medical science, 84, 9, 1277, 1282, Japanese Society of Veterinary Science, 2022年09月12日, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), A 12-year and 3-month spayed female mixed cat was presented with severe lumbar pain. Magnetic resonance imaging and postmortem examination revealed a swollen lesion in the spinal cord at L3 level. Histologic examination identified extensive neoplastic cell proliferation with massive necrosis in the tumor tissue. Two types of neoplastic cells were recognized. One type of neoplastic cells were large cells characterized by round to polygonal shape and abundant eosinophilic cytoplasm (referred to as "large cells"). The other neoplastic cells were small, densely proliferated, and had round to irregular shape and scant eosinophilic cytoplasm (referred to as "small cells"). Both types of cells were positive for oligodendrocyte transcription factor 2 and SRY-box transcription factor 10. Glial fibrillary acidic protein was positive in large cells but negative in most small cells. Digital analysis for Ki-67-stained tumor tissues found that total 21.1% ± 6.5% of tumor cells were positive for Ki-67. Based on these findings, we diagnosed malignant oligoastrocytoma in the spinal cord.
  • Urinary corticoid to creatinine ratios using IMMULITE 2000 XPi for diagnosis of canine hypercortisolism.
    Noriyuki Nagata; Hiryu Sawamura; Keitaro Morishita; Kenji Hosoya; Nozomu Yokoyama; Kazuyoshi Sasaoka; Noboru Sasaki; Kensuke Nakamura; Yoshinori Ikenaka; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 84, 7, 954, 959, 2022年07月10日, [査読有り], [最終著者, 責任著者], [国内誌]
    英語, 研究論文(学術雑誌), The urinary corticoid to creatinine ratio (UCCR) is one of the most commonly used screening tests for canine hypercortisolism (HC). In this study, a reference interval was established for UCCR using IMMULITE 2000 XPi, the latest chemiluminescence enzyme immunoassay. The diagnostic performance of this method for UCCR in canine HC was also evaluated. The median UCCR was 1.06 × 10-5 (range: 0.28-2.49) for 58 healthy dogs, and an upper reference limit of 1.98 × 10-5 (90% confidence interval: 1.76-2.15) was determined. The median UCCR in the 12 dogs with HC (7.38 × 10-5, range 1.86-29.98) was significantly higher than that in the 16 dogs with mimic-HC (1.59 × 10-5, range 0.47-3.42, P<0.001). The area under the curve for UCCR to differentiate HC dogs from mimic-HC dogs was 0.971, with a sensitivity of 91.7% and specificity of 100% when the cut-off value was set at 3.77 × 10-5. The UCCR of 16 paired urine samples collected at home and in hospital showed that the UCCR of samples collected in the hospital was significantly higher than that of samples collected at home (mean difference 3.30 × 10-5, 95% confidence interval: 0.70-5.90, P=0.001). In summary, we established the upper reference limit for UCCR using IMMULITE 2000 XPi in dogs and confirmed that UCCR is a useful diagnostic test for HC in dogs if urine samples are collected at home.
  • Characterization of mucin gene expression and goblet cell proportion in inflammatory colorectal polyps in miniature dachshunds.
    Noriyuki Nagata; Hiroshi Ohta; Nozomu Yokoyama; Yong Bin Teoh; Noboru Sasaki; Kensuke Nakamura; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 84, 6, 872, 876, 2022年06月18日, [査読有り], [最終著者, 責任著者], [国内誌]
    英語, 研究論文(学術雑誌), Hyperplastic goblet cells and abundant mucus are significant characteristics of inflammatory colorectal polyps (ICRPs) in miniature dachshunds. In this study, selected mucin gene expressions and goblet cell proportions were evaluated in miniature dachshunds with ICRPs and in healthy dogs. Mucin 2 (MUC2) gene expression was not significantly different among the groups, whereas mucin 5AC (MUC5AC) gene expression was significantly higher in the polypoid lesions than in healthy colonic mucosa. Although the percentage of goblet cells in the upper crypt regions did not significantly differ between the groups, that in the lower crypt regions was significantly decreased in polypoid lesions. In conclusion, increased MUC5AC gene expression and goblet cell proportion changes may be associated with the pathogenesis of ICRPs.
  • Incremental predictive value of echocardiographic indices of right ventricular function in the assessment of long-term prognosis in dogs with myxomatous mitral valve disease
    T. Morita; K. Nakamura; T. Osuga; M. Takiguchi
    Journal of Veterinary Cardiology, 39, 51, 62, 2022年02月, [査読有り], [最終著者]
    研究論文(学術雑誌)
  • Transcranial Doppler ultrasonography detects the elevation of cerebral blood flow during ictal-phase of pentetrazol-induced seizures in dogs.
    Kazuyoshi Sasaoka; Hiroshi Ohta; Tomohito Ishizuka; Kazuki Kojima; Noboru Sasaki; Mitsuyoshi Takiguchi
    American journal of veterinary research, 83, 4, 331, 338, 2022年01月28日, [査読有り], [責任著者], [国際誌]
    英語, 研究論文(学術雑誌), OBJECTIVE: To investigate the association between changes in cerebral blood flow and electrographic epileptic seizure in dogs using transcranial Doppler ultrasonography (TCD). ANIMALS: 6 healthy Beagle dogs. PROCEDURES: Each dog was administered pentetrazol (1.5 mg/kg/min) or saline (0.9% NaCl) solution under general anesthesia with continuous infusion of propofol. Both pentetrazol and saline solution were administered to all 6 dogs, with at least 28 days interval between the experiments. Blood flow waveforms in the middle cerebral artery and the basilar artery were obtained using TCD at baseline, after pentetrazol administration, and after diazepam administration. TCD velocities, including peak systolic velocity, end-diastolic velocity, and mean velocity and resistance variables, were determined from the Doppler waveforms. RESULTS: During ictal-phase of pentetrazol-induced seizures, the TCD velocities significantly increased in the basilar and middle cerebral arteries while TCD vascular resistance variables did not change in either artery. The TCD velocities significantly decreased after diazepam administration. Systemic parameters, such as the heart rate, mean arterial pressure, systemic vascular resistance, cardiac index, end-tidal carbon dioxide, oxygen saturation, and body temperature, did not change significantly during seizures. CLINICAL RELEVANCE: This study showed that cerebral blood flow, as obtained from TCD velocities, increased by 130% during ictal-phase of pentetrazol-induced seizures in dogs. The elevated velocities returned to baseline after seizure suppression. Thus, TCD may be used to detect electrographic seizures during the treatment of status epilepticus in dogs, and further clinical studies clarifying the association between changes in cerebral blood flow and non-convulsive seizure cases are needed.
  • Serum steroid profiling of hepatocellular carcinoma associated with hyperadrenocorticism in dogs: A preliminary study.
    Thandar Oo; Noboru Sasaki; Yoshinori Ikenaka; Takahiro Ichise; Noriyuki Nagata; Nozomu Yokoyama; Kazuyoshi Sasaoka; Keitaro Morishita; Kensuke Nakamura; Mitsuyoshi Takiguchi
    Frontiers in veterinary science, 9, 1014792, 1014792, 2022年, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common primary liver tumors in humans and dogs. Excessive adrenocortical hormone exposure may cause steroid hepatopathy, which may develop into HCC. In our previous study, hyperadrenocorticism (HAC) was a highly concurrent disease in dogs with HCC. Therefore, this study hypothesized that adrenal steroid alterations might be involved in hepatocarcinogenesis and aimed to specify the relationship between HAC and HCC in dogs. MATERIALS AND METHODS: This study included 46 dogs brought to the Hokkaido University Veterinary Teaching Hospital between March 2019 and December 2020. Owners gave their signed consent for blood collection on their first visit. A total of 19 steroids (14 steroids and 5 metabolites) in the baseline serum of 15 dogs with HCC, 15 dogs with HAC, and 10 dogs with both diseases were quantitatively measured using the developed liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) method. RESULTS: In each group, 11 steroids were detected higher than 50%. The detection rate of steroid hormones did not significantly differ between the groups (p > 0.05). Principle component analysis (PCA) showed that the steroid profiles of the three groups were comparable. Median steroid hormone concentrations were not significantly different between the study diseases (p > 0.05). CONCLUSION: The developed LC/MS/MS was useful for measuring steroid hormones. Although it was clear that HAC was concurrent in dogs with HCC, none of the serum steroids was suggested to be involved in HCC.
  • Evaluation of Right Ventricular Function and Dyssynchrony in a Dog Model of Acute Pulmonary Embolism: Diagnostic Utility and Reversibility.
    Tomoya Morita; Kensuke Nakamura; Tatsuyuki Osuga; Sei Kawamoto; Shingo Miki; Mitsuyoshi Takiguchi
    Frontiers in veterinary science, 9, 861064, 861064, 2022年, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), Background: The diagnosis of acute pulmonary thromboembolism is challenging in dogs. Little has been reported on changes in echocardiographic indices in dogs with acute pulmonary thromboembolism. The objective of this study was to validate the relationship between echocardiographic indices and right heart catheterization variables in dogs with acute pulmonary embolism and to identify a useful echocardiographic index for diagnosing acute pulmonary embolism. Materials and Methods: Six healthy laboratory beagles were included in the study. Echocardiography and right heart catheterization were performed in a dog model of acute pulmonary embolism produced by microsphere injection. Echocardiographic indices, including the right ventricular (RV) Tei index, RV longitudinal strain, and the dyssynchrony index using speckle tracking echocardiography, transmitral flow, and eccentricity index, were measured. Results: The mean pulmonary arterial pressure increased (22.2 ± 1.2 mmHg) and the blood pressure decreased after microsphere injection. Although the mean pulmonary arterial pressure remained elevated, the blood pressure recovered 2 days after the microsphere injection. Most echocardiographic indices of RV function were significantly impaired following microsphere injection and recovered after 2 days. In contrast, the RV Tei index was significantly impaired after microsphere injection and the impairment persisted after 2 days. Multivariable analysis revealed that the RV Tei index was an independent echocardiographic predictor of pulmonary vascular resistance (β = 0.88, P < 0.001), and transmitral early diastolic wave was an independent predictor of the cardiac index (β = -0.86, P = 0.001). Conclusions: The RV Tei index is a useful echocardiographic index for diagnosing acute pulmonary embolism. Ventricular interdependence may be an important factor causing low cardiac output in dogs with acute pulmonary embolism.
  • Case Report: Usefulness of Drip Infusion Cholangiography With Computed Tomography for the Diagnosis of Biloma in a Dog.
    Masahiro Tamura; Hiroshi Ohta; Nene Hasegawa; Kenji Hosoya; Mitsuyoshi Takiguchi
    Frontiers in veterinary science, 9, 854042, 854042, 2022年, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), Bilomas are encapsulated collections of bile outside or inside the biliary tract within the abdominal cavity. For diagnostic and therapeutic approaches, it is important to identify the origin of bile leaks from the biliary tract. This case report describes the usefulness of drip infusion cholangiography with computed tomography (DIC-CT) for detecting the site of bile leakage in a dog with biloma. A 10-year-old, castrated male Pomeranian dog was referred to our department for gastrointestinal signs. Abdominal ultrasonography detected gallbladder mucocele without evidence of defect on the wall and well-defined anechoic localized fluid accumulation around the right division of the liver. On the other hand, there was only a small amount of ascites in the abdominal cavity. The accumulated fluid collected through abdominocentesis had a bilirubin concentration of 11.4 mg/dl, which was more than twice as high as that in serum (0.4 mg/dl), but had absence of pyogenic bacteria. The DIC-CT with meglumine iotroxate showed two well-defined large fluid collections: one between right medial and lateral lobe and the other between the right lateral lobe and caudate process of caudate lobe. Three-dimensional DIC-CT views that the former was enhanced by the contrast agent and that it communicated with an intrahepatic bile duct of the right lateral lobe. Moreover, the DIC-CT images confirmed communication with each fluid collections. After 6 days of hospitalization, a decrease in the amount of accumulated fluid was confirmed, after which cholecystectomy was performed. The dog was discharged from the hospital without complications. No signs of bile leakage were observed on follow-up imaging on postoperative day 10. According to authors knowledge, this has been the first report to show that DIC-CT can be useful for determining the origin of bile leakage in dogs with bilomas.
  • Safety Assessment of Ultrasound-Assisted Intravesical Chemotherapy in Normal Dogs: A Pilot Study.
    Noboru Sasaki; Yoshinori Ikenaka; Keisuke Aoshima; Teiichiro Aoyagi; Nobuki Kudo; Kensuke Nakamura; Mitsuyoshi Takiguchi
    Frontiers in pharmacology, 13, 837754, 837754, 2022年, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), Intravesical chemotherapy after transurethral resection is a treatment option in patients with non-muscle invasive bladder cancer. The efficacy of intravesical chemotherapy is determined by the cellular uptake of intravesical drugs. Therefore, drug delivery technologies in the urinary bladder are promising tools for enhancing the efficacy of intravesical chemotherapy. Ultrasound-triggered microbubble cavitation may enhance the permeability of the urothelium, and thus may have potential as a drug delivery technology in the urinary bladder. Meanwhile, the enhanced permeability may increase systemic absorption of intravesical drugs, which may increase the adverse effects of the drug. The aim of this preliminary safety study was to assess the systemic absorption of an intravesical drug that was delivered by ultrasound-triggered microbubble cavitation in the urinary bladder of normal dogs. Pirarubicin, a derivative of doxorubicin, and an ultrasound contrast agent (Sonazoid) microbubbles were administered in the urinary bladder. Ultrasound (transmitting frequency 5 MHz; pulse duration 0.44 μsec; pulse repetition frequency 7.7 kHz; peak negative pressure -1.2 MPa) was exposed to the bladder using a diagnostic ultrasound probe (PLT-704SBT). The combination of ultrasound and microbubbles did not increase the plasma concentration of intravesical pirarubicin. In addition, hematoxylin and eosin staining showed that the combination of ultrasound and microbubble did not cause observable damages to the urothelium. Tissue pirarubicin concentration in the sonicated region was higher than that of the non-sonicated region in two of three dogs. The results of this pilot study demonstrate the safety of the combination of intravesical pirarubicin and ultrasound-triggered microbubble cavitation, that is, ultrasound-assisted intravesical chemotherapy.
  • Prognostic value of left ventricular-arterial coupling estimated using echocardiography in dogs with myxomatous mitral valve disease.
    Tatsuyuki Osuga; Tomoya Morita; Noboru Sasaki; Keitaro Morishita; Hiroshi Ohta; Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine, 35, 6, 2607, 2615, 2021年11月06日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), BACKGROUND: The interaction between the left ventricle (LV) and systemic arterial systems, known as left ventricular-arterial coupling (VAC), has been evaluated based on the effective arterial elastance (Ea) to LV end-systolic elastance (Ees) ratio (Ea/Ees). The Ea reflects the total arterial load of LV, whereas Ees reflects the LV systolic function. A recent study found that inappropriate VAC based on increased Ea/Ees estimated by echocardiography is associated with advanced disease severity in dogs with myxomatous mitral valve disease (MMVD). HYPOTHESIS: Inappropriate VAC assessed by echocardiographic estimation of Ea/Ees is associated with a worse prognosis in dogs with MMVD. ANIMALS: Eighty-nine dogs with MMVD. METHODS: Prospective cohort study. Dogs underwent echocardiographic examinations at enrollment. The Ea was estimated using the formula: mean blood pressure/(forward stroke volume/body weight). The Ees was estimated using the formula: mean blood pressure/(LV end-systolic volume/body weight). The Ea/Ees was calculated. RESULTS: By end of study, 22 dogs died of cardiac-related causes with 67 dogs censored. Dogs with increased Ea/Ees (Ea/Ees >0.34; median survival time, 527 days; 95% confidence interval [CI], 322 days-not determinable) had a shorter survival time (P < .0001) than those without increased Ea/Ees (Ea/Ees ≤0.34; median survival time, >1112 days; 95% CI, not determinable). Multivariate Cox proportional hazard analysis showed that Ea/Ees, body weight, peak systolic mitral annular velocity, and the peak early diastolic transmitral velocity-to-peak early diastolic mitral annular velocity ratio were independent predictors of cardiac-related death among echocardiographic indices. CONCLUSIONS AND CLINICAL IMPORTANCE: Inappropriate VAC assessed based on echocardiographically-estimated Ea/Ees is associated with a worse prognosis in dogs with MMVD.
  • The use of 4-dimensional magnetic resonance angiography as a noninvasive procedure to diagnose subclavian steal syndrome in a dog.
    Genya Shimbo; Ryosuke Echigo; Mitsuyoshi Takiguchi
    Journal of the American Veterinary Medical Association, 259, 9, 1040, 1042, 2021年11月01日, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), CASE DESCRIPTION: A 5-year-old 4.1-kg (9.0-lb) spayed female Toy Poodle was referred because of a 6-month history of sporadic signs of neck pain. CLINICAL FINDINGS: Diagnostic imaging with MRI and CT revealed a dilated radicular artery connecting the right and left vertebral arteries and causing mild compression of the spinal cord. The left subclavian artery caudal to the origin of the left vertebral artery was absent. Subclavian steal syndrome (SSS) was suspected. TREATMENT AND OUTCOME: The owner declined surgical treatment; thus, the dog was treated conservatively with glucocorticoids and analgesics. Eight months later, the dog's clinical signs were unchanged but palliated with the administration of glucocorticoids and analgesics, and 4-dimensional (4-D) magnetic resonance angiography (MRA) revealed that the left vertebral artery received blood supply from the right vertebral artery through the dilated radicular artery and that the left vertebral artery caudal to this site had retrograde flow and drained into the left subclavian artery, confirming the diagnosis of SSS. The owner again declined surgery, and conservative treatment continued. The dog's condition was unchanged at the last follow-up communication 11 months after 4-D MRA. CLINICAL RELEVANCE: Subclavian steal syndrome is an extremely rare condition in dogs, and our findings suggested that 4-D MRA could be used to definitively diagnose SSS in dogs.
  • Effects of intravenous administration of pimobendan on hemodynamic indices and indices of left atrial longitudinal strain derived from speckle-tracking echocardiography in healthy dogs.
    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, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Genome-wide DNA methylation analysis of dogs with high lead exposure living near a lead mining area in Kabwe, Zambia.
    Jumpei Yamazaki; Haruya Toyomaki; Shouta M M Nakayama; John Yabe; Kaampwe Muzandu; Jaroslav Jelinek; Shoko Yokoyama; Yoshinori Ikenaka; Mitsuyoshi Takiguchi; Mayumi Ishizuka
    Environmental pollution (Barking, Essex : 1987), 286, 117229, 117229, 2021年10月01日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Lead (Pb) is a heavy metal that has been proven to be toxic to both animals and humans. Genom-wide DNA methylation in domestic dogs exposed to high levels of Pb in Kabwe, Zambia was analyzed in this study. Using next-generation sequencing on samples from 20 domestic dogs (mean blood Pb concentration: 43.6 μg/dL and 7.2 μg/dL in the high and low exposure groups), a digital restriction enzyme analysis of methylation was performed to identify the genomic locations of differentially methylated CpG sites. A validation study on an additional 20 dogs followed (blood Pb concentration: 4.9-29.7 μg/dL). The cluster analysis resolved two broad clusters indicating high and low Pb exposure. The study identified 827 (1.2%) CpG sites with differences in methylation (101 CpG sites were hypermethylated in the low exposure group and 726 were hypermethylated in the high exposure group). The sites corresponded to 26 genes with differentially methylated CpG sites at their promoter regions, including the NGF gene. The methylation of four CpG sites was validated using bisulfite pyrosequencing. The results indicate that aberrant hypermethylation is prevalent in dogs exposed to Pb. The altered DNA methylation of the genes identified in this study contributes to a greater understanding of the epigenetic changes caused by Pb exposure and highlights novel biomarker discoveries across species.
  • Obese status is associated with accelerated DNA methylation change in peripheral blood of senior dogs.
    Jumpei Yamazaki; Shinji Meagawa; Jaroslav Jelinek; Shoko Yokoyama; Noriyuki Nagata; Masashi Yuki; Mitsuyoshi Takiguchi
    Research in veterinary science, 139, 193, 199, 2021年10月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Obesity and its associated comorbidities constitute a major and growing health problem worldwide not only involved with people but also dogs and cats. Although few genetic mutations have been associated with obesity in dogs, molecular mechanism remains to be clearly understood. Given the fact that DNA methylation leads to gene expression variability and has plasticity affected by metabolic phenotypes such as obesity in human, the objective of this study is to identify obesity-associated differentially methylated cytosine-phosphate-guanine (CpG) dinucleotide sites in dogs. With genome-wide DNA methylation analysis using next-generation sequencing for blood samples from fourteen Miniature dachshunds with body condition score (BCS) 4-5 and BCS ≥6, over 100,000 sites could be analysed to identify genomic locations of differentially methylated CpG sites. As a result, 191 differentially methylated CpG sites (89 CpG sites were hypermethylated in BCS ≥6 and 102 were hypermethylated in BCS 4-5) were identified. These sites included promoter regions of Kisspeptin receptor (KISS1R) and Calcyphosine 2 (CAPS2) genes which were subsequently validated by bisulfite-pyrosequencing for another set of 157 dog blood samples. KISS1R methylation levels were found to be higher in BCS ≥6 group than BCS 4-5 in senior (>84 months) dogs. Especially male dogs but not female dogs as well as uncastrated male dogs but not castrated male dogs showed this trend. DNA methylation of KISS1R gene will be useful for understanding of comprehensive epigenetic change in obese dogs.
  • Simultaneous steroids measurement in dogs with hyperadrenocorticism using a column-switching liquid chromatography-tandem mass spectrometry method.
    Noboru Sasaki; Thandar Oo; Yoshikazu Yasuda; Takahiro Ichise; Noriyuki Nagata; Nozomu Yokoyama; Kazuyoshi Sasaoka; Keitaro Morishita; Shouta Mm Nakayama; Mayumi Ishizuka; Kensuke Nakamura; Mitsuyoshi Takiguchi; Yoshinori Ikenaka
    The Journal of veterinary medical science, 83, 11, 1634, 1642, 2021年09月17日, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Genome-wide DNA methylation profile in feline haematological tumours: A preliminary study.
    Jumpei Yamazaki; Jaroslav Jelinek; Shoko Yokoyama; Mitsuyoshi Takiguchi
    Research in veterinary science, 140, 221, 228, 2021年09月08日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Although DNA methylation has been analysed in few studies for a limited number of loci in cats with diseases, genome-wide profile of DNA methylation has never been addressed. The hypothesis for this study is that next-generation sequencing with sequential digestion of genomic DNA with SmaI and XmaI enzymes could provide highly quantitative information on methylation levels in cats. Using blood from four healthy control cats and two disease cats as well as three feline lymphoma/leukemia cell lines, approximately 74-94 thousand CpG sites across the cat genome could be analysed. CpG sites in CpG island (CGI) were broadly either methylated or unmethylated in normal blood, while CpG sites in non-CpG islands (NCGI) are largely methylated. Lymphoma cell lines showed thousands of CpG sites with gain of methylation at normally unmethylated CGI sites and loss of methylation at normally methylated NCGI sites. Hypermethylated CpG sites located at promoter regions included genes annotated with 'developmental process' and 'anatomical structure morphogenesis' such as HOXD10. This highly quantitative method would be suitable for studies of DNA methylation changes not only in cancer but also in other common diseases in cats.
  • Systemic mucoid degeneration of the arterial tunica intima in a young dog.
    Yoshiki Ichikawa; Mizuki Heishima; Kristin Vyhnal; Keisuke Aoshima; Kazuyoshi Sasaoka; Ryohei Kinoshita; Atsushi Kobayashi; Mitsuyoshi Takiguchi; Takashi Kimura
    Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 34, 1, 10406387211042587, 10406387211042587, 2021年09月04日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), A 27-mo-old, spayed female mixed-breed dog was presented with left forelimb pain, which progressed to full thickness necrosis of the soft tissues of multiple limbs. Clinical imaging and postmortem examination suggested multiple large arterial thromboemboli. Histologic examination of vascular lesions revealed markedly thickened tunica intima with polypoid intraluminal projections, which partially to entirely occluded the arterial lumen. The expanded tunica intima was comprised of intimal accumulation of Alcian blue-positive matrix with scattered spindle-to-satellite cells. These cells were positive for von Willebrand factor and vimentin but negative for α-smooth muscle actin, suggesting endothelial origin. Deposition of the intimal mucoid matrix was observed in the elastic and muscular arteries associated with regional ischemic changes. Mucoid emboli, likely from fragmentation of proliferative intimal tissue, were identified in smaller vessels supplied by affected arteries. Based on these findings, we diagnosed systemic mucoid degeneration of the arterial tunica intima. Such systemic arterial degeneration characterized by deposition of mucoid matrix in the tunica intima has not been reported previously in dogs, to our knowledge, and should be distinguished from thromboembolism and other degenerative vascular diseases.
  • Cardiovascular effects of dose escalating of norepinephrine in healthy dogs anesthetized with isoflurane.
    Kazuki Kojima; Tomohito Ishizuka; Noboru Sasaki; Kensuke Nakamura; Mitsuyoshi Takiguchi
    Veterinary anaesthesia and analgesia, 48, 5, 654, 662, 2021年09月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Peliosis Hepatis with Chylous Ascites in a Dog.
    Kevin Christian Montecillo Gulay; Noriyuki Nagata; Keisuke Aoshima; Nozomi Shiohara; Atsushi Kobayashi; Mitsuyoshi Takiguchi; Takashi Kimura
    Journal of comparative pathology, 187, 63, 67, 2021年08月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), A 6-year-old spayed female Toy Poodle dog was referred to the Hokkaido University Veterinary Teaching Hospital for abdominal distension. Abdominocentesis yielded ascitic fluid that had a mildly increased total protein concentration and a 2.7-fold higher triglyceride concentration than plasma, and was interpreted as chylous ascites. The patient had an enlarged liver, which contained multiple, small, nodular masses and cyst-like structures. Microscopically, these lesions were multifocal dilated spaces containing lymphocytes, endothelial cells, fibrin and islands of hepatocytes. Increased α-smooth muscle actin-positive cells were observed in hepatic sinusoids. Based on these findings, we diagnosed peliosis hepatis with chylous ascites, which is likely to have been due to lymphangiectasia and disrupted hepatic sinusoids. Neither Bartonella spp DNA nor mutations in ACVRL1 and MTM1 genes were detected, although there was a 47-fold increase in hepatic ACVRL1 expression compared with age-matched control liver. To the authors' knowledge, this is the first report of chylous ascites resulting from peliosis hepatis in any species.
  • CT morphology of anomalous systemic arterial supply to normal lung in dogs.
    Genya Shimbo; Mitsuyoshi Takiguchi
    Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association, 62, 6, 657, 665, 2021年07月11日, [査読有り], [責任著者], [国際誌]
    英語, 研究論文(学術雑誌), Anomalous systemic arterial supply to the normal lung (ASANL) is a rare congenital anomaly in humans, in which the systemic arteries supply the basal segments of the lower lobe. It has a normal bronchial connection, but lacks a normal pulmonary artery. This anomaly has not been previously reported in the veterinary literature. The objectives of this retrospective descriptive study were to characterize the CT findings and clinical features of ASANL , and to determine the breed predisposition in a population of referral canine cases. Thoracic CT images, in which the caudal lung lobes were fully inflated and the pulmonary artery could be traced to the periphery, were reviewed. A total of 1,950 dogs were enrolled, and the aberrant vasculature equivalent to ASANL in humans was detected in 48 dogs. Shetland Sheepdogs (7/48, odds ratio [OR] = 8.0, P < 0.00001), Miniature Dachshunds (19/48, OR = 3.9, P < 0.00001), and Labrador Retrievers (6/48, OR = 4.5, P = 0.0009) were over-represented. The affected lung lobes were the right caudal lobe (24/48, 50%), the left caudal lobe (21/48, 43.8%), and bilateral caudal lobes (3/48, 6.3%). The aberrant vessels originated from the left gastric artery (14/48), descending thoracic aorta (8/48), celiac artery (6/48), and splenic artery (1/48). In the remaining 19 cases, the origin of the aberrant vessels could not be determined. Although the clinical significance of ASANL in dogs remains unclear, surgeons should be aware of this finding prior to lobectomy of the caudal lung lobes to avoid intraoperative systemic arterial bleeding.
  • Morphometric evaluation of canine hepatocellular carcinoma using computed tomography: a promising tool for predicting malignancy.
    Rommaneeya Leela-Arporn; Hiroshi Ohta; Genya Shimbo; Noboru Sasaki; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 83, 9, 1459, 1464, 2021年07月06日, [査読有り], [責任著者], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Extrahepatic biliary obstruction can interfere with hepatic fibrosis prediction using two-dimensional shear wave elastography in dogs.
    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, [査読有り], [責任著者], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • The effects of fipronil on emotional and cognitive behaviors in mammals.
    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, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • DNA methylation landscape of 16 canine somatic tissues by methylation-sensitive restriction enzyme-based next generation sequencing.
    Jumpei Yamazaki; Yuki Matsumoto; Jaroslav Jelinek; Teita Ishizaki; Shingo Maeda; Kei Watanabe; Genki Ishihara; Junya Yamagishi; Mitsuyoshi Takiguchi
    Scientific reports, 11, 1, 10005, 10005, 2021年05月11日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), DNA methylation plays important functions in gene expression regulation that is involved in individual development and various diseases. DNA methylation has been well studied in human and model organisms, but only limited data exist in companion animals like dog. Using methylation-sensitive restriction enzyme-based next generation sequencing (Canine DREAM), we obtained canine DNA methylation maps of 16 somatic tissues from two dogs. In total, we evaluated 130,861 CpG sites. The majority of CpG sites were either highly methylated (> 70%, 52.5-64.6% of all CpG sites analyzed) or unmethylated (< 30%, 22.5-28.0% of all CpG sites analyzed) which are methylation patterns similar to other species. The overall methylation status of CpG sites across the 32 methylomes were remarkably similar. However, the tissue types were clearly defined by principle component analysis and hierarchical clustering analysis with DNA methylome. We found 6416 CpG sites located closely at promoter region of genes and inverse correlation between DNA methylation and gene expression of these genes. Our study provides basic dataset for DNA methylation profiles in dogs.
  • Urinary free metanephrines measurement in dogs with adrenal gland diseases using a new simple liquid chromatography tandem mass spectrometry method.
    Noboru Sasaki; Yoshinori Ikenaka; Yumiko Inoue; Takahiro Ichise; Noriyuki Nagata; Mayumi Ishizuka; Syouta Mm Nakayama; Kensuke Nakamura; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 83, 4, 648, 655, 2021年04月09日, [査読有り], [責任著者], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Repeatability, reproducibility, and reference intervals for indices of right atrial longitudinal strain derived from speckle-tracking echocardiography in healthy dogs.
    Tomoya Morita; Kensuke Nakamura; Tatsuyuki Osuga; Mitsuyoshi Takiguchi
    American journal of veterinary research, 82, 4, 274, 279, 2021年04月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), OBJECTIVE: To determine repeatability, reproducibility, and reference intervals of indices of right atrial longitudinal strain (RALS) derived from speckle-tracking echocardiography (STE) in dogs without heart disease. ANIMALS: 110 client-owned dogs and 10 laboratory Beagles. PROCEDURES: To determine intraobserver within-day (repeatability) and interobserver (reproducibility) coefficients of variation, RALS during ventricular systole (ϵS), ventricular early diastole (ϵE), and atrial systole (ϵA), as derived with STE, were obtained by 2 investigators for 5 randomly selected client-owned dogs and analyzed by linear regression. Reference intervals were estimated from the results of all dogs. Correlations between RALS indices (ϵS, ϵE, and ϵA) and sex, age, body weight, heart rate, and blood pressure were determined. RESULTS: RALS derived from STE showed good intraobserver within-day repeatability and interobserver reproducibility, with coefficients of variation of < 20%. Both ϵS and ϵE were significantly negatively correlated with age, but ϵA was not correlated with age. Indices were not correlated with sex, body weight, or blood pressure. CONCLUSIONS AND CLINICAL RELEVANCE: RALS indices derived from STE were repeatable and reproducible and were affected by the age of dogs without heart disease. Age should be considered in the interpretation of RALS indices in clinical settings. Further studies are needed to apply RALS indices for assessing dogs with heart disease.
  • Prognostic value of small intestinal dilatation in dogs with protein-losing enteropathy.
    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, [査読有り], [最終著者], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Reduced expression levels of heat shock protein 90 in a diminazene aceturate-resistant Babesia gibsoni isolate.
    Masahiro Yamasaki; Natsuki Idaka; Moeko Abe; Mitsuyoshi Takiguchi
    Experimental parasitology, 221, 108050, 108050, 2021年02月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Heat shock protein 90 (HSP90) is a molecular chaperon and an essential component for stage differentiation and intracellular growth inside the host cells of many protozoans. HSP90 of Babesia gibsoni (BgHSP90) was suggested to function in the development of diminazene aceturate (DA)-resistance. Therefore, we examined the expression level of BgHSP90 in a DA-resistant B. gibsoni isolate. Transcription of the BgHSP90 gene in the DA-resistant isolate and wild-type B. gibsoni was assessed by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). As a result, the copy number and relative amount of BgHSP90 transcripts in the DA-resistant isolate were significantly lower than those in the wild-type. Moreover, a rabbit anti-recombinant BgHSP90 antibody was developed, and the protein synthesis of BgHSP90 in the DA-resistant isolate was compared with that in the wild-type by Western blot analysis and indirect fluorescence assay. There was significantly less BgHSP90 protein than in the wild-type. Additionally, the relative intensity of BgHSP70 in DA-resistant isolate was also lower than that in the wild-type. This suggested that the expression of BgHSP90 and BgHSP70 in the DA-resistant B. gibsoni isolate was suppressed and that the reduced amount of BgHSP90 and BgHSP70 might cause the weak proliferation of the DA-resistant isolate. Further studies are necessary to elucidate the function of BgHSP90.
  • Echocardiographic estimation of left ventricular-arterial coupling in dogs with myxomatous mitral valve disease.
    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, [査読有り], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Acute effects of intravenous pimobendan administration in dog models of chronic precapillary pulmonary hypertension
    T. Morita; K. Nakamura; T. Osuga; S. Kawamoto; S. Miki; K. Sasaoka; M. Takiguchi
    Journal of Veterinary Cardiology, 32, 16, 27, 2020年12月, [査読有り], [最終著者]
    研究論文(学術雑誌)
  • Long interspersed nucleotide element-1 hypomethylation in canine malignant mucosal melanoma.
    Teita Ishizaki; Jumpei Yamazaki; Shinji Meagawa; Nozomu Yokoyama; Keisuke Aoshima; Mitsuyoshi Takiguchi; Takashi Kimura
    Veterinary and comparative oncology, 18, 4, 854, 860, 2020年12月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Canine malignant melanoma is a common cancer with a high mortality rate and is a clinically important disease. DNA methylation has been considered to be a potential tumorigenic mechanism through aberrant DNA methylation at promoter region which represses gene transcription. Global hypomethylation could also facilitate chromosome instability. There are few reports regarding DNA methylation in canine malignant melanoma; therefore, the purpose of this study was to examine DNA methylation status of long interspersed nucleotide element-1 (LINE-1) to be a surrogate marker of genome-wide methylation changes in this disease. We measured levels of DNA methylation of two adjacent cytosine-guanine sites on CpG island (CGI) at the putative promoter of canine LINE-1 sequence by bisulphite-pyrosequencing in 41 canine melanoma patient samples as well as six cell lines compared with normal mucosae. The survival rates were obtained from owners or medical records. We found DNA methylation levels of LINE-1 in normal mucosae were methylated. Interestingly, both melanoma cell lines and clinical melanoma samples showed remarkable hypomethylation. In addition, patients with lower LINE-1 methylation showed worse prognosis than those with higher LINE-1 methylation, though the difference did not reach statistical significance (P = .09). Here, we demonstrate that hypomethylation of LINE-1 is an epigenetically aberrant feature in canine melanoma with possible prognostic value.
  • Wobbly hedgehog syndrome with disseminated histiocytic sarcoma and lateral ventricular meningioma in an African pygmy hedgehog.
    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, [査読有り], [最終著者], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Gene expression of leucine-rich alpha-2 glycoprotein in the polypoid lesion of inflammatory colorectal polyps in miniature dachshunds.
    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, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Altered hepatic cytochrome P450 expression in cats after chronic exposure to decabromodiphenyl ether (BDE-209).
    Kraisiri Khidkhan; Hazuki Mizukawa; Yoshinori Ikenaka; Shouta M M Nakayama; Kei Nomiyama; Nozomu Yokoyama; Osamu Ichii; Mitsuyoshi Takiguchi; Shinsuke Tanabe; Mayumi Ishizuka
    The Journal of veterinary medical science, 82, 7, 978, 982, 2020年07月31日, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), The knowledge of cytochrome P450 (CYP) expression involved in chemical exposure are necessary in clinical applications for the medication and prediction of adverse effects. The aim of this study was to evaluate the mRNA expression of CYP1-CYP3 families in cats exposed to BDE-209 for one year. All selected CYP isoforms showed no significant difference in mRNA expressions between control and exposure groups, however, CYP3A12 and CYP3A131 revealed tend to be two times higher in the exposure group compared to control group. The present results indicate that the chronic exposure of BDE209 could not alter CYP expression in the liver of cats. This result considered caused by the deficiency of CYP2B subfamily which is major metabolism enzyme of polybrominated diphenyl ethers (PBDEs) in cat.
  • An area ratio of thyroid gland to common carotid artery for evaluating the thyroid gland size.
    Noboru Sasaki; Noriyuki Nagata; Keitaro Morishita; Tatsuyuki Osuga; Kazuyoshi Sasaoka; Nozomu Yokoyama; Hiroshi Ohta; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 82, 7, 1012, 1016, 2020年07月31日, [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Activities of matrix metalloproteinase-2, matrix metalloproteinase-9, and serine proteases in samples of the colorectal mucosa of Miniature Dachshunds with inflammatory colorectal polyps.
    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], [最終著者, 責任著者], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Wobbly hedgehog syndrome with disseminated histiocytic sarcoma and lateral ventricular meningioma in an African pygmy hedgehog
    Lesa A. Thompson; Atsuya Morita; Shoko Murakami; Noboru Sasaki; Miou Murashita; Ryou Yamazaki; Atsushi Kobayashi; Takashi Kimura; Mitsuyoshi Takiguchi
    J Vet Diagn Invest, 2020年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Altered hepatic cytochrome P450 expression in cats after chronic exposure to decabromodiphenyl ether (BDE-209).
    Kraisiri Khidkhan; Hazuki Mizukawa; Yoshinori Ikenaka; Shouta M M Nakayama; Kei Nomiyama; Nozomu Yokoyama; Osamu Ichii; Mitsuyoshi Takiguchi; Shinsuke Tanabe; Mayumi Ishizuka
    The Journal of veterinary medical science, 82, 7, 978, 982, 2020年05月21日, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), The knowledge of cytochrome P450 (CYP) expression involved in chemical exposure are necessary in clinical applications for the medication and prediction of adverse effects. The aim of this study was to evaluate the mRNA expression of CYP1-CYP3 families in cats exposed to BDE-209 for one year. All selected CYP isoforms showed no significant difference in mRNA expressions between control and exposure groups, however, CYP3A12 and CYP3A131 revealed tend to be two times higher in the exposure group compared to control group. The present results indicate that the chronic exposure of BDE209 could not alter CYP expression in the liver of cats. This result considered caused by the deficiency of CYP2B subfamily which is major metabolism enzyme of polybrominated diphenyl ethers (PBDEs) in cat.
  • Genome-wide DNA methylation analysis in canine gastrointestinal lymphoma.
    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03月25日, [査読有り], [最終著者], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Long interspersed nucleotide element-1 hypomethylation in canine malignant mucosal melanoma.
    Teita Ishizaki; Jumpei Yamazaki; Shinji Meagawa; Nozomu Yokoyama; Keisuke Aoshima; Mitsuyoshi Takiguchi; Takashi Kimura
    Veterinary and comparative oncology, 18, 4, 854, 860, 2020年03月18日, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Canine malignant melanoma is a common cancer with a high mortality rate and is a clinically important disease. DNA methylation has been considered to be a potential tumorigenic mechanism through aberrant DNA methylation at promoter region which represses gene transcription. Global hypomethylation could also facilitate chromosome instability. There are few reports regarding DNA methylation in canine malignant melanoma; therefore, the purpose of this study was to examine DNA methylation status of long interspersed nucleotide element-1 (LINE-1) to be a surrogate marker of genome-wide methylation changes in this disease. We measured levels of DNA methylation of two adjacent cytosine-guanine sites on CpG island (CGI) at the putative promoter of canine LINE-1 sequence by bisulphite-pyrosequencing in 41 canine melanoma patient samples as well as six cell lines compared with normal mucosae. The survival rates were obtained from owners or medical records. We found DNA methylation levels of LINE-1 in normal mucosae were methylated. Interestingly, both melanoma cell lines and clinical melanoma samples showed remarkable hypomethylation. In addition, patients with lower LINE-1 methylation showed worse prognosis than those with higher LINE-1 methylation, though the difference did not reach statistical significance (P = .09). Here, we demonstrate that hypomethylation of LINE-1 is an epigenetically aberrant feature in canine melanoma with possible prognostic value.
  • Clinical characteristics of dogs with food-responsive protein-losing enteropathy.
    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], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Computed tomographic features for differentiating benign from malignant liver lesions in dogs.
    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], [最終著者, 責任著者], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Tissue distribution and characterization of feline cytochrome P450 genes related to polychlorinated biphenyl exposure.
    Khidkhan K; Mizukawa H; Ikenaka Y; Nakayama SMM; Nomiyama K; Yokoyama N; Ichii O; Darwish WS; Takiguchi M; Tanabe S; Ishizuka M
    Comparative biochemistry and physiology. Toxicology & pharmacology : CBP, 226, 108613, 108613, 2019年12月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Computed tomographic features for differentiating benign from malignant liver lesions in dogs.
    Leela-Arporn R; Ohta H; Shimbo G; Hanazono K; Osuga T; Morishita K; Sasaki N; Takiguchi M
    The Journal of veterinary medical science, 81, 12, 1697, 1704, 2019年12月, [査読有り]
  • Effects of PCB exposure on serum thyroid hormone levels in dogs and cats.
    Takaguchi K; Nishikawa H; Mizukawa H; Tanoue R; Yokoyama N; Ichii O; Takiguchi M; Nakayama SMM; Ikenaka Y; Kunisue T; Ishizuka M; Tanabe S; Iwata H; Nomiyama K
    The Science of the total environment, 688, 1172, 1183, 2019年10月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) might disrupt thyroid function. However, there is no clear evidence of PCB exposure disrupting thyroid hormone (TH) homeostasis in dogs and cats. The present study conducted in vivo experiments to evaluate the effects of a mixture of 12 PCB congeners (CB18, 28, 70, 77, 99, 101, 118, 138, 153, 180, 187 and 202, each congener 0.5 mg/kg BW, i.p. administration) on serum TH levels in male dogs (Canis lupus familiaris) and male cats (Felis silvestris catus). In PCB-exposed dogs, the time courses of higher-chlorinated PCBs and L-thyroxine (T4)-like OH-PCBs (4-OH-CB107 and 4-OH-CB202) concentrations were unchanged or tended to increase, whereas those of lower-chlorinated PCBs and OH-PCBs tended to decrease after 24 h. In PCB-exposed cats, concentrations of PCBs increased until 6 h and then remained unchanged. The levels of lower-chlorinated OH-PCBs including 4'-OH-CB18 increased until 96 h and then decreased. In PCB-exposed dogs, free T4 concentrations were higher than those in the control group at 48 and 96 h after PCB administration and positively correlated with the levels of T4-like OH-PCBs, suggesting competitive binding of T4 and T4-like OH-PCBs to a TH transporter, transthyretin. Serum levels of total T4 and total 3,3',5-triiodo-L-thyronine (T3) in PCB-exposed dogs were lower than in the control group at 24 and 48 h and negatively correlated with PCB concentrations, implying that PCB exposure enhanced TH excretion by increasing TH uptake and TH conjugation enzyme activities in the dog liver. In contrast, no obvious changes in TH levels were observed in PCB-exposed cats. This could be explained by the lower levels of T4-like OH-PCBs and lower hepatic conjugation enzyme activities in cats compared with dogs. Different effects on serum TH levels in PCB-exposed dogs and cats are likely to be attributable to species-specific PCB and TH metabolism.
  • Change in right ventricular function in an American cocker spaniel with acute pulmonary thromboembolism.
    Morita T; Nakamura K; Osuga T; Hanazono K; Morishita K; Takiguchi M
    The Journal of veterinary medical science, 81, 9, 1259, 1265, 2019年09月03日, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), A 12-year-old neutered female American cocker spaniel weighing 9.9 kg was presented for evaluation with a 2-day history of dyspnea and anorexia. Echocardiography revealed severe pulmonary hypertension (estimated systolic pulmonary arterial pressure, 93.4 mmHg) with right heart enlargement, pulmonary arterial dilation, and right ventricular dysfunction. The dilation of left heart and congenital cardiac shunt were not observed. Pulmonary thromboembolism (PTE) was confirmed by computed tomographic angiography. After treatment with antiplatelet and anticoagulant, the clinical sign and the echocardiographic abnormality of right heart were improved. These echocardiographic findings are not specific for PTE, but it can be useful as a rule-in test for PTE when other causes of pulmonary hypertension are excluded and a monitor of therapeutic efficacy.
  • Usefulness of noninvasive shear wave elastography for the assessment of hepatic fibrosis in dogs with hepatic disease.
    Tamura M; Ohta H; Shimbo G; Osuga T; Sasaki N; Morishita K; Kagawa Y; Takiguchi M
    Journal of veterinary internal medicine, 33, 5, 2067, 2074, 2019年09月, [査読有り], [最終著者, 責任著者]
    英語
  • Effect of ultra low fat diet on regulatory T cells of dogs with intestinal limphangiectasia secondary to chronic enteropathy: A pilot study
    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], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌)
  • Findings of contrast-enhanced ultrasonography with Sonazoid for cholangiocellular adenoma in three dogs.
    Tamura M; Nakamura K; Osuga T; Shimbo G; Sasaki N; Morishita K; Ohta H; Takiguchi M
    The Journal of veterinary medical science, 81, 8, 1104, 1108, 2019年08月, [査読有り]
  • Plasma amino acid profiles in dogs with inflammatory bowel disease.
    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, [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Plasma-free amino acid profiles in dogs with hepatocellular carcinoma.
    Leela-Arporn R; Ohta H; Tamura M; Nagata N; Sasaoka K; Dermlim A; Nisa K; Osuga T; Morishita K; Sasaki N; Takiguchi M
    Journal of veterinary internal medicine, 33, 4, 1653, 1659, 2019年07月, [査読有り]
  • Effect of acute volume loading on left atrial strain values derived from two-dimensional speckle tracking echocardiography in dogs.
    Dermlim A; Osuga T; Nakamura K; Morita T; Nisa K; Sasaoka K; Leela-Arporn R; Nagata N; Tamura M; Sasaki N; Ohta H; Takiguchi M
    The Journal of veterinary medical science, 81, 7, 949, 957, 2019年07月, [査読有り]
  • Epidemiology of massive hepatocellular carcinoma in dogs: A 4-year retrospective study.
    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, Elsevier BV, 2019年06月, [査読有り]
    研究論文(学術雑誌)
  • Right ventricular function and dyssynchrony measured by echocardiography in dogs with precapillary pulmonary hypertension
    T. Morita; K. Nakamura; T. Osuga; K. Morishita; N. Sasaki; H. Ohta; M. Takiguchi
    Journal of Veterinary Cardiology, 23, 1, 14, Elsevier {BV}, 2019年06月, [査読有り]
    研究論文(学術雑誌)
  • The repeatability and left atrial strain analysis obtained via speckle tracking echocardiography in healthy dogs.
    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, Elsevier BV, 2019年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Predictive factors of malignancy in dogs with focal liver lesions using clinical data and ultrasonographic features.
    Leela-Arporn R; Ohta H; Tamura M; Nagata N; Sasaoka K; Dermlim A; Nisa K; Morishita K; Sasaki N; Nakamura K; Takagi S; Hosoya K; Takiguchi M
    The Journal of veterinary medical science, 81, 5, 723, 729, 2019年05月, [査読有り]
  • Plasma amino acid profiles in dogs with inflammatory bowel disease.
    Tamura Y; Ohta H; Kagawa Y; Osuga T; Morishita K; Sasaki N; Takiguchi M
    Journal of veterinary internal medicine, 2019年05月, [査読有り]
  • Evaluation of liver and spleen stiffness of healthy dogs by use of two-dimensional shear wave elastography.
    Tamura M; Ohta H; Nisa K; Osuga T; Sasaki N; Morishita K; Takiguchi M
    American journal of veterinary research, 80, 4, 378, 384, 2019年04月, [査読有り], [最終著者, 責任著者]
  • Evaluation of duodenal perfusion by contrast-enhanced ultrasonography in dogs with chronic inflammatory enteropathy and intestinal lymphoma.
    Nisa K; Lim SY; Shinohara M; Osuga T; Yokoyama N; Tamura M; Nagata N; Sasaoka K; Dermlim A; Leela-Arporn R; Morita T; Sasaki N; Morishita K; Nakamura K; Ohta H; Takiguchi M
    Journal of Veterinary Internal Medicine, 33, 2, 559, 568, 2019年03月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌)
  • Contrast-enhanced ultrasonography is a feasible technique for quantifying hepatic microvascular perfusion in dogs with extrahepatic congenital portosystemic shunts.
    Tamura M; Ohta H; Nisa K; Osuga T; Sasaki N; Morishita K; Takiguchi M
    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]
  • Low-intensity pulsed ultrasound modifies effects of a myelin-related growth inhibitor and enhances neurite re-growth
    Noboru Sasaki; Nobuki Kudo; Hiroshi Ohta; Mitsuyoshi Takiguchi
    2019 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), 1308, 1310, 2019年
    英語, 研究論文(国際会議プロシーディングス)
  • Corrigendum: Urinary Exosome-Derived microRNAs Reflecting the Changes in Renal Function in Cats.
    Ichii O; Ohta H; Horino T; Nakamura T; Hosotani M; Mizoguchi T; Morishita K; Nakamura K; Sasaki N; Takiguchi M; Sato R; Oyamada K; Elewa YHA; Kon Y
    Frontiers in veterinary science, 6, 2, 2019年, [査読有り]
  • Effect of acute volume overload on echocardiographic indices of right ventricular function and dyssynchrony assessed by use of speckle tracking echocardiography in healthy dogs.
    Morita T; Nakamura K; Osuga T; Yokoyama N; Morishita K; Sasaki N; Ohta H; Takiguchi M
    American journal of veterinary research, 80, 1, 51, 60, 2019年01月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌), 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.
  • Effects of immunosuppressive prednisolone therapy on pancreatic tissue and concentration of canine pancreatic lipase immunoreactivity in healthy dogs.
    Ohta H; Kojima K; Yokoyama N; Sasaki N; Kagawa Y; Hanazono K; Ishizuka T; Morishita K; Nakamura K; Takagi S; Takiguchi M
    Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 82, 4, 278, 286, 2018年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • ECG of the Month.
    Osuga T; Nakamura K; Morita T; Watanabe K; Takiguchi M
    Journal of the American Veterinary Medical Association, 253, 4, 417, 420, 2018年08月, [査読有り]
  • Pulmonary hypertension due to unclassified interstitial lung disease in a Pembroke Welsh corgi.
    Morita T; Nakamura K; Osuga T; Kobayashi A; Ichii O; Yabuki A; Takiguchi M
    The Journal of veterinary medical science, 80, 6, 939, 944, 2018年06月, [査読有り]
  • The effect of sedation with a combination of butorphanol and midazolam on quantitative contrast-enhanced ultrasonography of duodenum in healthy dogs.
    Nisa K; Lim SY; Osuga T; Yokoyama N; Tamura M; Nagata N; Sasaoka K; Dermlim A; Leela-Arporn R; Morita T; Sasaki N; Morishita K; Nakamura K; Ohta H; Takiguchi M
    The Journal of Veterinary Medical Science, 80, 3, 453, 459, 2018年03月, [査読有り]
    英語, 研究論文(学術雑誌)
  • The effect of sedation with a combination of butorphanol and midazolam on quantitative contrast-enhanced ultrasonography of duodenum in healthy dogs
    Nisa K; Lim S.Y; Osuga T; Yokoyama N; Tamura M; Nagata N; Sasaoka K; Dermlim A; Leela-Arporn R; Morita T; Sasaki N; Morishita K; Nakamura K; Ohta H; Takiguchi M
    Journal of Veterinary Medical Science, 80, 3, 453, 459, 2018年03月, [査読有り]
    研究論文(学術雑誌)
  • Urinary Exosome-Derived microRNAs Reflecting the Changes in Renal Function in Cats.
    Ichii O; Ohta H; Horino T; Nakamura T; Hosotani M; Mizoguchi T; Morishita K; Nakamura K; Sasaki N; Takiguchi M; Sato R; Oyamada K; Elewa YHA; Kon Y
    Frontiers in veterinary science, 5, 289, 2018年, [査読有り]
  • Transcranial Doppler Ultrasound Examination in Dogs with Suspected Intracranial Hypertension Caused by Neurologic Diseases
    Sasaoka K; Nakamura K; Osuga T; Morita T; Yokoyama N; Morishita K; Sasaki N; Ohta H; Takiguchi M
    Journal of Veterinary Internal Medicine, 32, 1, 314, 323, 2018年, [査読有り]
    研究論文(学術雑誌)
  • Intracellular diminazene aceturate content and adenosine incorporation in diminazene aceturate-resistant Babesia gibsoni isolate in vitro.
    Yamasaki M; Watanabe N; Idaka N; Yamamori T; Otsuguro KI; Uchida N; Iguchi A; Ohta H; Takiguchi M
    Experimental parasitology, 183, 92, 98, 2017年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Case report: Congenital methemoglobinemia in a cat with the reduced NADH-cytochrome b5 reductase 3 activity and missense mutations in CYB5R3
    Akiyoshi Tani; Jumpei Yamazaki; Kensuke Nakamura; Mitsuyoshi Takiguchi; Mutsumi Inaba
    Japanese Journal of Veterinary Research, 65, 4, 201, 206, Faculty of Veterinary Medicine, Hokkaido University, 2017年11月, [査読有り]
    英語
  • Spatial and temporal profile of cisplatin delivery by ultrasound-assisted intravesical chemotherapy in a bladder cancer model
    Noboru Sasaki; Kazuhiro Ishi; Nobuki Kudo; Shouta M. M. Nakayama; Kensuke Nakamura; Keitaro Morishita; Hiroshi Ohta; Mayumi Ishizuka; Mitsuyoshi Takiguchi
    PLOS ONE, 12, 11, e0188093, 2017年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog
    Osuga T; Nakamura K; Morita T; Kagawa Y; Ohta H; Takiguchi M
    Canadian Veterinary Journal, 58, 11, 1167, 1170, 2017年11月, [査読有り]
  • Repeatability and reproducibility of quantitative contrast-enhanced ultrasonography for assessing duodenal perfusion in healthy dogs.
    Nisa K; Lim SY; Shinohara M; Nagata N; Sasaoka K; Dermlim A; Leela-Arporn R; Morita T; Yokoyama N; Osuga T; Sasaki N; Morishita K; Nakamura K; Ohta H; Takiguchi M
    The Journal of Veterinary Medical Science, 79, 9, 1585, 1590, 2017年09月, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Repeatability and reproducibility of quantitative contrast-enhanced ultrasonography for assessing duodenal perfusion in healthy dogs
    Nisa K; Lim S.Y; Shinohara M; Nagata N; Sasaoka K; Dermlim A; Leela-Arporn R; Morita T; Yokoyama N; Osuga T; Sasaki N; Morishita K; Nakamura K; Ohta H; Takiguchi M
    Journal of Veterinary Medical Science, 79, 9, 1585, 1590, 2017年09月, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌)
  • Brain micro-inflammation at specific vessels dysregulates organ-homeostasis via the activation of a new neural circuit
    Yasunobu Arima; Takuto Ohki; Naoki Nishikawa; Kotaro Higuchi; Mitsutoshi Ota; Yuki Tanaka; Junko Nio-Kobayashi; Mohamed Elfeky; Ryota Sakai; Yuki Mori; Tadafumi Kawamoto; Andrea Stofkova; Yukihiro Sakashita; Yuji Morimoto; Masaki Kuwatani; Toshihihiko Iwanaga; Yoshichika Yoshioka; Naoya Sakamoto; Akihiko Yoshimura; Mitsuyoshi Takiguchi; Saburo Sakoda; Marco Prinz; Daisuke Kamimura; Masaaki Murakami
    ELIFE, 6, 2017年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Changes in right ventricular function assessed by echocardiography in dog models of mild RV pressure overload
    Morita T; Nakamura K; Osuga T; Yokoyama N; Morishita K; Sasaki N; Ohta H; Takiguchi M
    Echocardiography, 34, 7, 1040, 1049, 2017年07月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Stimulation of colorectal biopsies from miniature dachshunds with inflammatory colorectal polyps with toll-like receptor ligands: A pilot study
    Yokoyama N; Ohta H; Kagawa Y; Nagata N; Nisa K; Morita T; Osuga T; Sasaki N; Morishita K; Nakamura K; Takiguchi M
    Veterinary Immunology and Immunopathology, 188, 78, 83, 2017年06月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Washout Ratio in the Hepatic Vein Measured by Contrast-Enhanced Ultrasonography to Distinguish Between Inflammatory and Noninflammatory Hepatic Disorders in Dogs
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Washout Ratio in the Hepatic Vein Measured by Contrast-Enhanced Ultrasonography to Distinguish Between Inflammatory and Noninflammatory Hepatic Disorders in Dogs.
    Morishita K; Hiramoto A; Michishita A; Takagi S; Osuga T; Lim SY; Nakamura K; Sasaki N; Ohta H; Takiguchi M
    Journal of veterinary internal medicine, 31, 3, 770, 777, 2017年05月, [査読有り]
  • Assessment of contrast-enhanced ultrasonography of the hepatic vein for detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs
    Keitaro Morishita; Akira Hiramoto; Asuka Michishita; Satoshi Takagi; Yuki Hoshino; Takaharu Itami; Sue Yee Lim; Tatsuyuki Osuga; Sayuri Nakamura; Kenji Ochiai; Kensuke Nakamura; Hiroshi Ohta; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH, 78, 4, 465, 471, 2017年04月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Expression of apical junction complex proteins in colorectal mucosa of miniature dachshunds with inflammatory colorectal polyps
    Yokoyama N; Ohta H; Kagawa Y; Leela-Arporn R; Dermlim A; Nisa K; Morita T; Osuga T; Sasaki N; Morishita K; Nakamura K; Takiguchi M
    Journal of Veterinary Medical Science, 79, 3, 456, 463, 2017年03月, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌)
  • Contrast-enhanced ultrasonography of the hepatic vein in normal dogs.
    Morishita K; Hiramoto A; Osuga T; Lim SY; Khoirun N; Sasaki N; Nakamura K; Ohta H; Yamasaki M; Takiguchi M
    The Journal of veterinary medical science, 78, 12, 1753, 1758, 2017年01月, [査読有り], [最終著者, 責任著者], [国内誌]
    英語, 研究論文(学術雑誌), 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® (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.
  • Impact of surgical margins on survival of 37 dogs with massive hepatocellular carcinoma
    A. Matsuyama; S. Takagi; K. Hosoya; Y. Kagawa; K. Nakamura; T. Deguchi; M. Takiguchi
    NEW ZEALAND VETERINARY JOURNAL, 65, 5, 227, 231, 2017年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Urinary exosome-derived microRNAs reflecting the changes of renal function and histopathology in dogs
    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]
    英語, 研究論文(学術雑誌)
  • Serial measurement of pancreatic lipase immunoreactivity concentration in dogs with immune-mediated disease treated with prednisolone
    Ohta H; Morita T; Yokoyama N; Osuga T; Sasaki N; Morishita K; Nakamura K; Takiguchi M
    Journal of Small Animal Practice, 58, 6, 342, 347, 2017年, [査読有り]
    研究論文(学術雑誌)
  • Localization of Toll-like Receptor (TLR) 2 and TLR4 mRNA in the Colorectal Mucosa of Miniature Dachshunds with Inflammatory Colorectal Polyps
    Yokoyama N; Ohta H; Yamazaki J; Kagawa Y; Ichii O; Khoirun N; Morita T; Osuga T; Lim S.Y; Sasaki N; Morishita K; Nakamura K; Takiguchi M
    Journal of Comparative Pathology, 156, 2-3, 183, 190, 2017年, [査読有り]
    研究論文(学術雑誌)
  • Left Atrial Strain at Different Stages of Myxomatous Mitral Valve Disease in Dogs
    Nakamura K; Kawamoto S; Osuga T; Morita T; Sasaki N; Morishita K; Ohta H; Takiguchi M
    Journal of Veterinary Internal Medicine, 31, 2, 316, 325, 2017年, [査読有り]
  • The repeatability and characteristics of right ventricular longitudinal strain imaging by speckle-tracking echocardiography in healthy dogs
    Morita T; Nakamura K; Osuga T; Yokoyama N; Khoirun N; Morishita K; Sasaki N; Ohta H; Takiguchi M
    Journal of Veterinary Cardiology, 19, 4, 351, 362, 2017年, [査読有り]
    研究論文(学術雑誌)
  • Molecular cloning, phylogenetic analysis and heat shock response of Babesia gibsoni heat shock protein 90.
    Masahiro Yamasaki; Yoshihiro Tsuboi; Yusuke Taniyama; Naohiro Uchida; Reeko Sato; Kensuke Nakamura; Hiroshi Ohta; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 78, 8, 1355, 60, 2016年09月01日, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), The Babesia gibsoni heat shock protein 90 (BgHSP90) gene was cloned and sequenced. The length of the gene was 2,610 bp with two introns. This gene was amplified from cDNA corresponding to full length coding sequence (CDS) with an open reading frame of 2,148 bp. A phylogenetic analysis of the CDS of HSP90 gene showed that B. gibsoni was most closely related to B. bovis and Babesia sp. BQ1/Lintan and lies within a phylogenetic cluster of protozoa. Moreover, mRNA transcription profile for BgHSP90 exposed to high temperature were examined by quantitative real-time reverse transcription-polymerase chain reaction. BgHSP90 levels were elevated when the parasites were incubated at 43°C for 1 hr.
  • Effects of experimental cardiac volume loading on left atrial phasic function in healthy dogs
    Osuga T; Nakamura K; Morita T; Nisa K; Yokoyama N; Sasaki N; Morishita K; Ohta H; Takiguchi M
    American Journal of Veterinary Research, 77, 9, 952, 960, 2016年09月, [査読有り], [国際誌]
    英語, 研究論文(学術雑誌)
  • Hypercalcemia in a Dog with Chronic Ingestion of Maxacalcitol Ointment.
    Nakamura K; Tohyama N; Yamasaki M; Ohta H; Morishita K; Takiguchi M
    Journal of the American Animal Hospital Association, 52, 4, 256, 258, 2016年07月, [査読有り]
  • Repeatability and reproducibility of right ventricular Tei index valves derived from three echocardiographic methods for evaluation of cardiac function in dogs
    Morita T; Nakamura K; Osuga T; Lim S.Y; Yokoyama N; Morishita K; Ohta H; Takiguchi M
    American Journal of Veterinary Research, 77, 7, 715, 720, 2016年07月, [査読有り]
    研究論文(学術雑誌)
  • Prognostic Value of Right Ventricular Tei Index in Dogs with Myxomatous Mitral Valvular Heart Disease
    Nakamura K; Morita T; Osuga T; Morishita K; Sasaki N; Ohta H; Takiguchi M
    Journal of Veterinary Internal Medicine, 30, 1, 69, 75, Wiley-Blackwell, 2016年, [査読有り]
    英語
  • Effects of various cardiovascular drugs on indices obtained with two-dimensional speckle tracking echocardiography of the left atrium and time-left atrial area curve analysis in healthy dogs
    Tatsuyuki Osuga; Kensuke Nakamura; Tomoya Morita; Sue Yee Lim; Nozomu Yokoyama; Keitaro Morishita; Hiroshi Ohta; Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH, 76, 8, 702, 709, 2015年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Quantitative contrast-enhanced ultrasonographic assessment of naturally occurring pancreatitis in dogs.
    Lim SY; Nakamura K; Morishita K; Sasaki N; Murakami M; Osuga T; Yokoyama N; Ohta H; Yamasaki M; Takiguchi M
    Journal of veterinary internal medicine / American College of Veterinary Internal Medicine, 29, 1, 71, 78, 2015年01月, [査読有り]
    研究論文(学術雑誌)
  • Vitamin D Status in Different Stages of Disease Severity in Dogs with Chronic Valvular Heart Disease
    Osuga T; Nakamura K; Morita T; Lim S.Y; Nisa K; Yokoyama N; Sasaki N; Morishita K; Ohta H; Takiguchi M
    Journal of Veterinary Internal Medicine, 29, 6, 1518, 1523, 2015年, [査読有り]
    研究論文(学術雑誌)
  • CONTRAST-ENHANCED ULTRASONOGRAPHIC FINDINGS IN THREE DOGS WITH PANCREATIC INSULINOMA
    Kensuke Nakamura; Sue-Yee Lim; Kenji Ochiai; Masahiro Yamasaki; Hiroshi Ohta; Keitaro Morishita; Satoshi Takagi; Mitsuyoshi Takiguchi
    VETERINARY RADIOLOGY & ULTRASOUND, 56, 1, 55, 62, 2015年01月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Lesion Type Classification by Applying Machine-Learning Technique to Contrast-Enhanced Ultrasound Images
    Kazuya Takagi; Satoshi Kondo; Kensuke Nakamura; Mitsuyoshi Takiguchi
    IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E97D, 11, 2947, 2954, 2014年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Evaluation of Selected Cytokine Gene Expression in Colonic Mucosa from Dogs with Idiopathic Lymphocytic-plasmacytic Colitis
    Yu Tamura; Hiroshi Ohta; Nozomu Yokoyama; Sue Yee Lim; Tatsuyuki Osuga; Keitaro Morishita; Kensuke Nakamura; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE, 76, 10, 1407, 1410, 2014年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • In vitro and in vivo safety and efficacy Studies of amphotericin B on Babesia gibsoni
    Masahiro Yamasaki; Eriko Harada; Yu Tamura; Sue Yee Lim; Tatsuyuki Ohsuga; Nozomu Yokoyama; Keitaro Morishita; Kensuke Nakamura; Hiroshi Ohta; Mitsuyoshi Takiguchi
    VETERINARY PARASITOLOGY, 205, 3-4, 424, 433, 2014年10月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Case report: Protein-losing enteropathy caused by Mesocestoides vogae (syn. M. corti) in a dog
    Yu Tamura; Hiroshi Ohta; Takuya Kashiide; Jun Matsumoto; Tatsuya Sakurai; Nozomu Yokoyama; Keitaro Morishita; Kensuke Nakamura; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    VETERINARY PARASITOLOGY, 205, 1-2, 412, 415, 2014年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • First detection of Echinococcus multilocularis infection in two species of nonhuman primates raised in a zoo: A fatal case in Cercopithecus diana and a strongly suspected case of spontaneous recovery in Macaca nigra
    Kimiaki Yamano; Hirokazu Kouguchi; Kohji Uraguchi; Takeshi Mukai; Chikako Shibata; Hideaki Yamamoto; Noboru Takaesu; Masaki Ito; Yoshinori Makino; Mitsuyoshi Takiguchi; Kinpei Yagi
    PARASITOLOGY INTERNATIONAL, 63, 4, 621, 626, 2014年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Expression of apical junction complex proteins in duodenal mucosa of dogs with inflammatory bowel disease
    Hiroshi Ohta; Yuji Sunden; Nozomu Yokoyama; Tatsuyuki Osuga; Sue Yee Lim; Yu Tamura; Keitaro Morishita; Kensuke Nakamura; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH, 75, 8, 746, 751, 2014年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Qualitative and Quantitative Contrast-Enhanced Ultrasonographic Assessment of Cerulein-Induced Acute Pancreatitis in Dogs
    S. Y. Lim; K. Nakamura; K. Morishita; N. Sasaki; M. Murakami; T. Osuga; H. Ohta; M. Yamasaki; M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE, 28, 2, 496, 503, 2014年03月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌)
  • CD4⁺ T cell cytokine gene and protein expression in duodenal mucosa of dogs with inflammatory bowel disease.
    Ohta H; Takada K; Sunden Y; Tamura Y; Osuga T; Lim SY; Murakami M; Sasaki N; Wickramasekara; Rajapakshage BK; Nakamura K; Yamasaki M; Takiguchi M
    The Journal of veterinary medical science / the Japanese Society of Veterinary Science, 76, 3, 409, 414, 2014年03月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Ultrasound image-guided therapy enhances antitumor effect of cisplatin.
    Noboru Sasaki; Nobuki Kudo; Kensuke Nakamura; Sue Yee Lim; Masahiro Murakami; W R Bandula Kumara; Yu Tamura; Hiroshi Ohta; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    Journal of medical ultrasonics (2001), 41, 1, 11, 21, 2014年01月, [査読有り], [国内誌]
    英語, 研究論文(学術雑誌), 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.
  • Prognostic Value of Left Atrial Function in Dogs with Chronic Mitral Valvular Heart Disease
    Nakamura K; Osuga T; Morishita K; Suzuki S; Morita T; Yokoyama N; Ohta H; Yamasaki M; Takiguchi M
    Journal of Veterinary Internal Medicine, 28, 6, 1746, 1752, Wiley-Blackwell, 2014年, [査読有り]
    英語
  • Qualitative and Quantitative Contrast Enhanced Ultrasonography of the Pancreas Using Bolus Injection and Continuous Infusion Methods in Normal Dogs
    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]
    英語, 研究論文(学術雑誌)
  • LC-MS/MS analysis of canine lipoproteins fractionated using the ultracentrifugation-precipitation method.
    Asuka Suto; Masahiro Yamasaki; Yukari Takasaki; Yasuyuki Fujita; Riichiro Abe; Hiroshi Shimizu; Hiroshi Ohta; Mitsuyoshi Takiguchi
    The Journal of veterinary medical science, 75, 11, 1471, 7, 2013年11月, [査読有り], [国内誌]
    英語, Due to the lack of a gold standard method in canine lipoprotein analysis, it is unclear whether canine high-density lipoprotein (HDL) and low-density lipoprotein (LDL) can be accurately evaluated by the lipoprotein analysis methods used for dogs. This study investigated whether the ultracentrifugation-precipitation (U-P) method was suitable as a gold standard method for analyzing canine lipoprotein. First, the U-P method was compared with a gel permeation high-performance liquid chromatography system (GP-HPLC). The concentrations of canine HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) determined by the U-P method correlated closely with those determined by GP-HPLC. However, the canine HDL-C concentration determined by the U-P method was lower than that determined by GP-HPLC, and the canine LDL-C concentration determined by the U-P method was higher than that determined by GP-HPLC. This study showed that some canine HDL could be precipitated with heparin manganese chloride solution. Second, the HDL and LDL fractions separated by the U-P method were analyzed by LC-MS/MS. The HDL fraction was found to contain only apolipoprotein A-I, which is an apolipoprotein of HDL, whereas the LDL fraction contained both apolipoprotein A-I and apolipoprotein B-100, which is an apolipoprotein of LDL. This data showed that a certain lipoprotein that includes apolipoprotein A-I might precipitate with canine LDL when using heparin manganese chloride solution. These results indicated that the U-P method is not currently a gold standard method for analyzing canine lipoproteins.
  • Markedly increased expression of interleukin-8 in the colorectal mucosa of inflammatory colorectal polyps in miniature dachshunds
    Yu Tamura; Hiroshi Ohta; Shidow Torisu; Masashi Yuki; Nozomu Yokoyama; Masahiro Murakami; Sue Yee Lim; Tatsuyuki Osuga; Keitaro Morishita; Kensuke Nakamura; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY, 156, 1-2, 32, 42, 2013年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Expression of CD4(+) T cell cytokine genes in the colorectal mucosa of inflammatory colorectal polyps in miniature dachshunds
    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]
    英語, 研究論文(学術雑誌)
  • Increased intratumoral fluorothymidine uptake levels following multikinase inhibitor sorafenib treatment in a human renal cell carcinoma xenograft model
    Masahiro Murakami; Songji Zhao; Yan Zhao; Wenwen Yu; Chowdhury Nusrat Fatema; Ken-Ichi Nishijima; Masahiro Yamasaki; Mitsuyoshi Takiguchi; Nagara Tamaki; Yuji Kuge
    Oncology Letters, 6, 3, 667, 672, 2013年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Repeatability and reproducibility of measurements obtained via two-dimensional speckle tracking echocardiography of the left atrium and time-left atrial area curve analysis in healthy dogs
    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]
    英語, 研究論文(学術雑誌)
  • Evaluation of changes in the tumor microenvironment after sorafenib therapy by sequential histology and F-18-fluoromisonidazole hypoxia imaging in renal cell carcinoma
    Masahiro Murakami; Songji Zhao; Yan Zhao; Nusrat Fatema Chowdhury; Wenwen Yu; Ken-Ichi Nishijima; Mitsuyoshi Takiguchi; Nagara Tamaki; Yuji Kuge
    INTERNATIONAL JOURNAL OF ONCOLOGY, 41, 5, 1593, 1600, 2012年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Link between inflammation and aquaporin-5 distribution in submandibular gland in sjögren's syndrome?
    M. S. Soyfoo; A. Konno; N. Bolaky; J. S. Oak; D. Fruman; C. Nicaise; M. Takiguchi; C. Delporte
    Oral Diseases, 18, 6, 568, 574, 2012年09月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Involvement of Mitochondrial Genes of Babesia gibsoni in Resistance to Diminazene Aceturate
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Bilateral Segmental Aplasia with Unilateral Uterine Horn Torsion in a Pomeranian Bitch
    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]
    英語, 研究論文(学術雑誌)
  • Analysis of energy generation and glycolysis pathway in diminazene aceturate-resistant Babesia gibsoni isolate in vitro
    Bandula Kumara Wickramasekara Rajapakshage; Masahiro Yamasaki; Masahiro Murakami; Yu Tamura; Sue Yee Lim; Tatsuyuki Osuga; Noboru Sasaki; Kensuke Nakamura; Hiroshi Ohta; Mitsuyoshi Takiguchi
    JAPANESE JOURNAL OF VETERINARY RESEARCH, 60, 2-3, 51, 61, 2012年08月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Enhanced Cytotoxic Effect of Cisplatin Using Diagnostic Ultrasound and Microbubbles In Vitro
    Sasaki Noboru; Nakamura Kensuke; Murakami Masahiro; Lim Sue Yee; Ohta Hiroshi; Yamasaki Masahiro; Takiguchi Mitsuyoshi
    11TH INTERNATIONAL SYMPOSIUM ON THERAPEUTIC ULTRASOUND, 1481, 307, 310, 2012年, [査読有り]
  • ACTIVATION OF MICROBUBBLES BY SHORT-PULSED ULTRASOUND ENHANCES THE CYTOTOXIC EFFECT OF CIS-DIAMMINEDICHLOROPLATINUM (II) IN A CANINE THYROID ADENOCARCINOMA CELL LINE IN VITRO
    Noboru Sasaki; Nobuki Kudo; Kensuke Nakamura; Sue Yee Lim; Masahiro Murakami; W. R. Bandula Kumara; Yu Tamura; Hiroshi Ohta; Masahiro Yamasaki; Mitsuyoshi Takiguchi
    ULTRASOUND IN MEDICINE AND BIOLOGY, 38, 1, 109, 118, 2012年01月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Effects and Mechanisms of Action of Polyene Macrolide Antibiotic Nystatin on Babesia gibsoni In Vitro
    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]
    英語, 研究論文(学術雑誌)
  • Effects of sildenafil citrate on five dogs with Eisenmenger's syndrome
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Pathological correlations between podocyte injuries and renal functions in canine and feline chronic kidney diseases.
    Ichii O; Yabuki A; Sasaki N; Otsuka S; Ohta H; Yamasaki M; Takiguchi M; Namiki Y; Hashimoto Y; Endoh D; Kon Y
    Histology and histopathology, 26, 10, 1243, 1255, Universidad de Murcia, 2011年10月, [査読有り]
    英語, Podocytes cover the glomerulus and their adjacent foot processes form a principal barrier called the slit diaphragm. Podocyte dysfunctions, including podocyte loss and slit diaphragm disruptions, induce chronic kidney diseases (CKD). In this study, we analyzed the correlations between podocyte injuries and renal dysfunctions in domestic carnivores. Dogs and cats were divided into normal and CKD groups according to renal histopathology and plasma creatinine values. Immunostaining results showed that linear reactions of slit diaphragm molecules, e.g., nephrin, podocin, and ACTN4, were parallel to glomerular capillaries in all animals. However, in dogs, reactions of nephrin and ACTN4 were changed to a granular pattern in the CKD group, and their intensities significantly decreased with the number of podocytes in the glomerulus. Moreover, the expression of nephrin and ACTN4 negatively correlated with creatinine. Real-time PCR analysis showed that nephrin mRNA expression in the kidneys of CKD dogs was significantly lower than that in normal animals, and negatively correlated with creatinine. Although no significant correlation between renal dysfunction and podocyte injury was detected in cats, histoplanimetric scores of tubulointerstitial lesions in CKD cats were higher than those in both normal cats and diseased dogs. Furthermore, mRNAs of WT1 and SD molecules were detected in urine from CKD animals. In conclusion, podocyte injuries such as podocytopenia and decreased expression of nephrin and ACTN4 in the glomerulus were more strongly correlated with renal dysfunction in dogs than in cats. These findings suggest that the CKD pathogenesis, especially susceptibilities to podocyte injuries, differed between dogs and cats.
  • Detection of anti-Babesia gibsoni heat shock protein 70 antibody and anti-canine heat shock protein 70 antibody in sera from Babesia gibsoni-infected dogs
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Expression and subcellular localization of apical junction proteins in canine duodenal and colonic mucosa
    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]
    英語, 研究論文(学術雑誌)
  • Altered expression of miR-146a correlates with the development of chronic renal inflammation.
    Ichii O; Yabuki A; Sasaki N; Otsuka S; Ohta H; Yamasaki M; Takiguchi M; Namiki Y; Hashimoto Y; Endoh D; Kon Y
    Kidney Int., 81, 3, 280, 292, 2011年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Babesia gibsoni: Detection in blood smears and formalin-fixed, paraffin-embedded tissues using deoxyribonucleic acid in situ hybridization analysis
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Contrast-enhanced ultrasonography for characterization of focal splenic lesions in dogs.
    Nakamura K; Sasaki N; Murakami M; Bandula Kumara WR; Ohta H; Yamasaki M; Takagi S; Osaki T; Takiguchi M
    Journal of veterinary internal medicine / American College of Veterinary Internal Medicine, 24, 6, 1290, 1297, 6, 2010年11月, [査読有り]
    Nakamura K, Sasaki N, Murakami M, Bandula Kumara WR, Ohta H, Yamasaki M, Takagi S, Osaki T, Takiguchi M, <i>Journal of veterinary internal medicine / American College of Veterinary Internal Medicine</i>, 2010, vol. 24, no. 6, pp. 1290-1297
  • Reduced transcript levels of the heat shock protein 70 gene in diminazene aceturate-resistant Babesia gibsoni variants under low concentrations of diminazene aceturate
    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]
    英語, 研究論文(学術雑誌)
  • Development and Characterization of a Strain of Babesia gibsoni Resistant to Diminazene Aceturate In Vitro
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Local overexpression of interleukin-1 family, member 6 relates to the development of tubulointerstitial lesions
    Osamu Ichii; Saori Otsuka; Nobuya Sasaki; Akira Yabuki; Hiroshi Ohta; Mitsuyoshi Takiguchi; Yoshiharu Hashimoto; Daiji Endoh; Yasuhiro Kon
    LABORATORY INVESTIGATION, 90, 3, 459, 475, 2010年03月, [査読有り]
    英語, 研究論文(学術雑誌)
  • CONTRAST-ENHANCED ULTRASONOGRAPHY FOR CHARACTERIZATION OF CANINE FOCAL LIVER LESIONS
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • EFFECTS AND MECHANISMS OF ACTION OF IONOPHOROUS ANTIBIOTICS VALINOMYCIN AND SALINOMYCIN-NA ON BABESIA GIBSONI IN VITRO
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • Primary Splenic Torsion in a Boston Terrier
    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, [査読有り]
    英語, 研究論文(学術雑誌)
  • QUANTITATIVE CONTRAST-ENHANCED ULTRASONOGRAPHY OF CANINE SPLEEN
    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]
    英語, 研究論文(学術雑誌)
  • Flow cytometry to evaluate the level of Babesia gibsoni parasitemia in vivo and in vitro by using the fluorescent nucleic acid stain SYTO16
    Masahiro Yamasaki; Shiang-Jyi Hwang; Hiroshi Ohta; Osamu Yamato; Yoshimitsu Maede; Mitsuyoshi Takiguchi
    JAPANESE JOURNAL OF VETERINARY RESEARCH, 55, 4, 129, 136, 2008年02月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Identification of a quantitative trait locus regulating B cell-dominant infiltration into autoimmune sialitis lesions of the IQI mouse model of primary Sjögren's syndrome.
    Konno A; Takiguchi M; Takada K; Usami T; Azumi K; Kubota H; Inaba M; Saegusa J; Kon Y
    Immunogenetics, 59, 11, 853, 859, 2007年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Restricted localization of claudin-16 at the tight junction in the thick ascending limb of Henle's loop together with claudins 3, 4, and 10 in bovine nephrons
    H Ohta; H Adachi; M Takiguchi; M Inaba
    JOURNAL OF VETERINARY MEDICAL SCIENCE, 68, 5, 453, 463, 2006年05月, [査読有り]
    英語
  • Magnetic resonance imaging of alveolar echinococcosis experimentally induced in the rat lung
    T Asanuma; T Kawahara; O Inanami; M Nakao; K Nakaya; A Ito; M Takiguchi; A Hashimoto; M Kuwabara
    JOURNAL OF VETERINARY MEDICAL SCIENCE, 68, 1, 15, 20, 2006年01月, [査読有り]
    英語
  • Different effects on the inflammatory lesions in the lacrimal and salivary glands after neonatal thymectomy in IQI/Jic mice, a model for Sjögren's syndrome.
    Takada K; Takiguchi M; Inaba M
    The Journal of veterinary medical science / the Japanese Society of Veterinary Science, 67, 9, 955, 957, 2005年09月, [査読有り]
    英語
  • Autoimmunity against a tissue kallikrein in IQI/Jic mice - A model for Sjogren's syndrome
    K Takada; M Takiguchi; A Konno; A Inaba
    JOURNAL OF BIOLOGICAL CHEMISTRY, 280, 5, 3982, 3988, 2005年02月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Diagnostic ultrasound of polypoid cystitis in dogs
    M Takiguchi; M Inaba
    JOURNAL OF VETERINARY MEDICAL SCIENCE, 67, 1, 57, 61, 2005年01月, [査読有り]
    英語
  • Magnetic resonance imaging and immunoblot analyses in rats with experimentally induced cerebral alveolar echinococcosis
    T Asanuma; Y Matsumoto; M Takiguchi; O Inanami; M Nakao; K Nakaya; A Ito; A Hashimoto; M Kuwabara
    COMPARATIVE MEDICINE, 53, 6, 649, 656, 2003年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Presence of B7-2+ dendritic cells and expression of Th1 cytokines in the early development of sialodacryoadenitis in the IqI/Jic mouse model of primary Sjörgren's syndrome.
    Konno A; Takada K; Saegusa J; Takiguchi M
    Autoimmunity, 36, 4, 247, 254, 2003年06月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Virologic and serologic identification of minute virus of canines (canine parvovirus type 1) from dogs in Japan
    M Mochizuki; M Hashimoto; T Hajima; M Takiguchi; A Hashimoto; Y Une; F Roerink; T Ohshima; CR Parrish; LE Carmichael
    JOURNAL OF CLINICAL MICROBIOLOGY, 40, 11, 3993, 3998, 2002年11月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Detection of Canine Herpesvirus DNA in the Ganglionic Neurons and the Lymph Node Lymphocytes of Latently Infected Dogs
    Masahiro Miyoshi; Yuki Ishii; Mitsuyoshi Takiguchi; Ayato Takada; Jun Yasuda; Akira Hashimoto; Katsunori Okazaki; Hiroshi Kida
    Journal of Veterinary Medical Science, 61, 4, 375, 379, 1999年04月, [査読有り]
    英語, 研究論文(学術雑誌)
  • イヌヘルペスウイルスの神経節神経細胞及びリンパ節リンパ球における潜伏感染
    三好 正浩; 石井 由紀; 滝口 満喜; 高田 礼人; 安田 隼; 橋本 晃; 岡崎 克則; 喜田 宏
    The Journal of Veterinary Medical Science, 61, 4, 375, 379, (公社)日本獣医学会, 1999年04月, [査読有り]
    英語
■ その他活動・業績
■ 主な担当授業
  • 伴侶動物獣医療実習, 2024年, 学士課程, 獣医学部
  • 臨床疾病学特論, 2024年, 博士後期課程, 獣医学院
  • 伴侶動物夜間・救急獣医療実習, 2024年, 学士課程, 獣医学部
  • 獣医内科学特論, 2024年, 博士後期課程, 獣医学院
  • 伴侶動物獣医療実習Ⅰ, 2024年, 学士課程, 獣医学部
  • 総合専門臨床特論, 2024年, 博士後期課程, 獣医学院
  • 伴侶動物獣医療実習Ⅱ, 2024年, 学士課程, 獣医学部
  • 夜間・救急獣医療実習Ⅱ, 2024年, 学士課程, 獣医学部
  • 夜間・救急獣医療実習Ⅰ, 2024年, 学士課程, 獣医学部
  • 獣医コミュニケーション演習, 2024年, 学士課程, 獣医学部
  • 夜間・救急獣医療実習Ⅱ, 2024年, 学士課程, 獣医学部
  • 伴侶動物獣医療実習Ⅰ, 2024年, 学士課程, 獣医学部
  • 総合獣医療実習, 2024年, 学士課程, 獣医学部
  • 伴侶動物獣医療実習Ⅱ, 2024年, 学士課程, 獣医学部
  • 獣医科学特別研究, 2024年, 博士後期課程, 獣医学院
  • 夜間・救急獣医療実習Ⅰ, 2024年, 学士課程, 獣医学部
  • 獣医科学特論演習, 2024年, 博士後期課程, 獣医学院
  • 総合獣医療実習, 2024年, 学士課程, 獣医学部
  • アドバンスト演習, 2024年, 学士課程, 獣医学部
  • アドバンスト演習, 2024年, 学士課程, 獣医学部
  • アドバンスト演習, 2024年, 学士課程, 獣医学部
  • 臨床動物栄養学, 2024年, 学士課程, 獣医学部
  • 臨床動物行動学, 2024年, 学士課程, 獣医学部
  • 内科学各論, 2024年, 学士課程, 獣医学部
  • 放射線獣医療・画像診断学, 2024年, 学士課程, 獣医学部
  • 内科学総論, 2024年, 学士課程, 獣医学部
■ 所属学協会
  • 国際獣医放射線学会
  • 日本小動物獣医学会
  • 日本超音波医学会
  • 日本獣医画像診断学会
  • 日本免疫学会
  • 日本獣医学会
■ 共同研究・競争的資金等の研究課題
  • 副腎皮質機能亢進症関連肝障害による肝細胞癌発症機序の解明
    科学研究費助成事業
    2023年04月01日 - 2026年03月31日
    滝口 満喜; 村上 正晃; 佐々木 東; 新坊 弦也; 横山 望
    日本学術振興会, 基盤研究(B), 北海道大学, 23K27067
  • 副腎皮質機能亢進症関連肝障害による肝細胞癌発症機序の解明
    科学研究費助成事業
    2023年04月01日 - 2026年03月31日
    滝口 満喜; 村上 正晃; 佐々木 東; 新坊 弦也; 横山 望
    日本学術振興会, 基盤研究(B), 北海道大学, 23H02374
  • がん特異的代謝システムを標的とした新規セノリティックテラピー開発のための基盤研究
    科学研究費助成事業 基盤研究(A)
    2020年04月01日 - 2025年03月31日
    稲波 修; 平岡 和佳子; 安井 博宣; 平田 拓; 滝口 満喜; 岡松 優子
    本年度はインビトロの培養細胞の系の実験で、以下の四つの結果が明らかとなった。
    1)グルタミン要求性の強いヒト肺がんA549細胞やH460細胞では、放射線照射により、これらの細胞でのグルタミンの取り込みの増大とグルタメートの増大、すなわちグルタミナーゼの活性化を起こす事を明らかにした。さらに、グルタミン代謝阻害剤添加あるいはグルタミン欠乏培地下で培養すると治療線量レベルの放射線照射によって多くの老化様細胞死とSASPの培養液中への分泌を増強させることが可能である事が明らかとなった。
    2)グルタミノリシス阻害条件下で放射線による老化様細胞死の誘発機構には活性酸素種の生成量、グルタチオン量の変化DNA損傷の量、さらにはDNA損傷に伴う伴うp53やp21、p16の発現変化などの既知のメカニズムの関与は殆ど無く、未知の機構の関与が示唆されている。
    3)更にグルタミノリシス阻害条件下で放射線誘発する老化様細胞死を起こす条件で、Bcl-XL阻害剤ABT-737によって、この増大した老化様細胞死の多くはアポトーシスに変換できること、いわゆるセノリシスを起こせることを明らかにした。
    4)一方では、同じ肺がん由来細胞でも786-o細胞ではグルタミン代謝阻害が老化様細胞の増強を起こさず、A549やH460細胞と同様の現象は観察されず、全ての肺がん細胞に於いて同様の機構が働いていない事も明らかとなった。また、脂質代謝阻害剤は老化様細胞増強には関与しなかった。
    以上の結果はグルタミン要求性の強い肺がん細胞を中心にその亜致死レベルのグルタミノリシス阻害条件下で治療線量レベルの放射線照射をすると、多量の老化様細胞死の増大が起こす事を示しており、さらに、アポトーシス抑制因子の阻害剤で効率よく老化様細胞死をアポトーシスに変換できることが明確になった。
    日本学術振興会, 基盤研究(A), 北海道大学, 20H00443
  • 副腎-肝臓連関によるイヌ肝細胞癌発症メカニズムの解明
    科学研究費助成事業 基盤研究(B)
    2020年04月01日 - 2023年03月31日
    滝口 満喜; 村上 正晃; 山崎 淳平; 池中 良徳
    犬の肝細胞癌における、ステロイドホルモン産生過剰を起点とする発がん仮説の検証を目指し、前年度に引き続いた検討を行った。2年目となる本年度は肝細胞癌・副腎皮質機能亢進症罹患犬における血中ステロイドホルモン・代謝産物のプロファイリング、ならびに肝臓組織でのエピゲノム変異の解析を遂行した。
    ステロイドプロファイリングでは前年度に確立した測定系を発展拡大させ、新たに6種の副腎皮質ホルモンと4種の代謝産物を合わせた、合計19種類のステロイドプロファイル解析が可能となった。この新たな測定系を用いて、肝細胞癌36症例、副腎皮質機能亢進症15症例、併発11症例、コントロール19症例を対象として、血液中のステロイドプロファイルを解析した。しかし、血液中のステロイドプロファイルに疾患特異性、もしくは疾患群間での差が認められなかった。
    DNAメチル化の解析では、実験的ステロイドホルモン誘発性脂肪肝、副腎皮質腫機能亢進症併発肝細胞癌および肝細胞癌単独症例の腫瘍組織と腫瘍近傍組織の、合計3種類の肝臓組織を用い、多段階発癌仮説の検証を試みた。その結果、脂肪肝・近傍組織・腫瘍組織と段階的なメチル化変化が存在し、腫瘍においてメチル化レベルの高い遺伝子が6、低い遺伝子が12、抽出できた。
    現時点では血中ステロイドプロファイルに肝細胞癌と副腎皮質機能亢進症との関連を示唆する血中ステロイドプロファイリングは見つかっていない。一方で、ステロイド肝から腫瘍への段階的なDNAメチル化レベルの変化が存在することが明らかになった。犬の肝細胞癌においてステロイドが発症に役割を果たしていることは十分に予想され、本年度の成果を複合的かつ詳細に解析することで、多段階発がん説の検証が進む。
    日本学術振興会, 基盤研究(B), 北海道大学, 20H03139
  • 超音波メカノバイオロジーによる神経軸索の伸展制御
    科学研究費助成事業 挑戦的研究(萌芽)
    2018年06月29日 - 2020年03月31日
    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。
    日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 18K19255
  • がん特異的グルタミン代謝とアセテート代謝を標的とした新規がん治療法の開発
    科学研究費助成事業 基盤研究(B)
    2017年04月01日 - 2020年03月31日
    稲波 修; 安井 博宣; 平田 拓; 滝口 満喜; 山盛 徹
    本研究ではがんの放射線治療の新たな代謝標的をあきらかにするために、新しい酸素プローブを用いた電子スピン共鳴法(ESR)を用いたがん代謝のミトコンドリア依存性代謝測定法を確立した。この方法を用いることで多くの固形がんの生存戦略として、グルコース代謝のみならず電子伝達系(ETC)の活性化によるATP産生が放射線照射により増加することを明らかにした。さらにこの放射線誘導エネルギー応答をTCA回路に関与するグルタミノリシスやミトコンドリア阻害剤薬により強い放射線増感を誘導できることを見いだした。特にグルタミンシンターゼ阻害剤やETC阻害薬が強い放射線増感効果を引き起こす事が出来ることを見いだした。
    日本学術振興会, 基盤研究(B), 北海道大学, 17H03920
  • 動物自然発生腫瘍に対するマイクロバブル併用超音波照射による実用的な新規がん治療
    科学研究費助成事業 基盤研究(B)
    2014年04月01日 - 2017年03月31日
    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。
    日本学術振興会, 基盤研究(B), 北海道大学, 26292155
  • マイクロバブルと超音波を利用した新しい増感放射線療法の開発
    科学研究費助成事業 挑戦的萌芽研究
    2014年04月01日 - 2016年03月31日
    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。
    日本学術振興会, 挑戦的萌芽研究, 北海道大学, 26660233
  • 動物自然発生腫瘍に対するマイクロバブル併用超音波照射による実用的な新規がん治療
    科学研究費補助金(基盤研究(B))
    2014年 - 2016年
    滝口 満喜
    文部科学省, 基盤研究(B), 北海道大学, 研究代表者, 競争的資金, 26292155
  • バベシア原虫の増殖および薬剤耐性獲得における熱ショックタンパク質90の役割の解明
    科学研究費助成事業 基盤研究(C)
    2012年04月01日 - 2015年03月31日
    山崎 真大; 大田 寛; 滝口 満喜
    本研究では犬の住血寄生原虫であるBabesia gibsoniの熱ショック蛋白質90(BgHsp90)に関する基礎的研究を実施した。BgHsp90の遺伝子をクローニング、塩基配列の解析を行い、抗BgHsp90抗体の作成を行った。これらを用いて遺伝し発現量の測定を行い、BgHsp90が原虫の増殖に貢献していること、原虫が熱ショックを受けたときに発現量が増加することを明らかにした。また、熱ショックタンパク質90阻害薬により、B. gibsoniの増殖を抑制することが可能であり、BgHsp90は治療のターゲットとなることが明らかになった。
    日本学術振興会, 基盤研究(C), 24580456
  • 犬における内臓リーシュマニア症の病態解明と原虫存続機構の分子基盤
    科学研究費助成事業 基盤研究(B)
    2012年04月01日 - 2015年03月31日
    片倉 賢; 加藤 大智; 滝口 満喜; 阿戸 学
    インド亜大陸の内臓リーシュマニア症の伝播における犬の役割は不明である。本研究では、バングラデシュの本症流行地において、犬のリーシュマニア感染調査を行い、約10%の野犬が抗体陽性あるいは末梢血のPCR陽性であることを明らかにした。次に、実験用ビーグル犬にリーシュマニア原虫を接種して解析した。その結果、臨床症状や血液性状に異常は認められず、また。PCR検査や原虫分離検査も陰性であったが、長期にわたる抗体産生が認められた。以上、Leishmania donovaniに感染した犬は、不顕性感染として原虫を保持する保虫宿主として、内臓リーシュマニ症の伝播に関与している可能性が考えられた。
    日本学術振興会, 基盤研究(B), 北海道大学, 24380163
  • マイクロバブルと超音波を利用した新しい増感放射線療法の開発
    科学研究費補助金(挑戦的萌芽研究)
    2014年 - 2015年
    滝口 満喜
    文部科学省, 挑戦的萌芽研究, 北海道大学, 研究代表者, 競争的資金, 26660233
  • バベシア原虫の増殖および薬剤耐性獲得における熱ショックタンパク質90の役割の解明
    科学研究費補助金(基盤研究(C))
    2012年 - 2014年
    山崎 真大; 大田 寛; 滝口 満喜
    犬に感染する赤血球内寄生原虫であるBabesia gibsoniのheat shock protein 90 (hsp90)について、平成25年度は以下の研究を行った。平成24年度には、組み替えhsp90蛋白質の作成のためにプラスミドを作成したが、これを大腸菌内に取り込ませ、大腸菌を用いた組み替えBabesia gibsoni hsp90 (Bghsp90)の発現を実施し、組み替えBghsp90蛋白質の作成に成功した。大腸菌の大量培養を実施することでこれを大量に発現させ、組み替え蛋白質に結合させたHisタグを利用して組み替えBghsp90蛋白質を精製した。さらに、組み替えBghsp90蛋白質をウサギに免疫し、ウサギの体内でこの蛋白質に対する抗血清を作成、さらに抗血清から組み替えBghsp90蛋白質を用いてアフィニティー精製を行ってウサギ抗組み替えBghsp90ポリクローナル抗体を作成した。この抗体がB. gibsoniのhsp90に特異的に結合することを確認した後に、これを用いてウェスタンブロッティングおよび免疫染色を行い、B. gibsoniの持つBghsp90蛋白質を検出、定量することに成功した。そこで、これらの技術を用いて、B. gibsoniの野生株、ならびに抗原虫薬であるジミナゼン製剤に耐性を持つ耐性株のhsp90量を比較し、耐性株ではhsp90発現量が減少していることを明らかにした。この結果は、昨年実施したリアルタイムPCR法を用いた遺伝子発現量の定量を行った実験とよく相関したことから、B. gibsoniのジミナゼン耐性株ではBghsp90の発現量が低下していることが明らかになった。
    文部科学省, 基盤研究(C), 北海道大学, 連携研究者, 競争的資金, 24580456
  • 客観的病態診断を可能とする新たな超音波検査法の確立と獣医臨床応用の進展
    科学研究費助成事業 基盤研究(C)
    2011年 - 2013年
    滝口 満喜; 山﨑 真大; 大田 寛
    伴侶動物における超音波検査による客観的病態診断の確立に向けた基盤を形成し、その臨床応用の進展を検討することを目的として、まず正常犬の膵臓の灌流状態に関する基礎的知見を得た。次いで、実験的に作出したセルレイン誘発性急性膵炎モデルにおける造影超音波検査所見を解析して、膵臓の血流変化に着目した急性膵炎の新しい診断基準を確立した。
    また、左心房機能に着目した心エコー図検査による新たな心機能評価法の確立を目指し、正常犬の左心房面積の時相による変化を解析して正常値を確立するとともに、本手法の再現性を明らかにし、臨床応用への基盤を構築した。
    日本学術振興会, 基盤研究(C), 北海道大学, 23580436
  • 客観的病態診断を可能とする新たな超音波検査法の確立と獣医臨床応用の進展
    科学研究費補助金(基盤研究(C))
    2011年 - 2013年
    滝口 満喜; 山崎 真大; 大田 寛
    本研究の目的は、伴侶動物における超音波検査による客観的病態診断の確立に向けた基盤を形成し、その臨床応用の進展を検討することである。まず、超音波造影剤ソナゾイドを用いた造影超音波検査の臨床応用の適用拡大を目的として、未だに診断が困難な膵炎に着目し、正常犬の膵臓の灌流状態に関する基礎的知見を得た。次いで、実験的に作出したセルレイン誘発性急性膵炎モデルにおける造影超音波検査所見を解析して、膵臓の血流変化に着目した急性膵炎の新しい診断基準を確立することを目指した。その結果、超音波造影剤ソナゾイドのボーラス投与(0.01ml/kg)では膵臓の至適観察時間が16秒と短かったため、ソナゾイドを0.05ml/kgで持続点滴することで観察時間を150秒に大幅に延長させる造影検査法を確立した(J Vet Med Sci, 75:1601-1607, 2013) 。また、セルレイン誘発浮腫性膵炎では、正常時に比べて膵実質のエコー輝度のピークまでの到達時間が短縮し、最高輝度が上昇することが明らかとなった(J Vet Intern Med, 28:496-503, 2014) 。これまでソナゾイドを用いた犬の膵臓の造影超音波検査に関する報告は皆無であり、本研究成果によって、犬の膵臓の造影超音波検査法が確立され、実験的に作出した浮腫性膵炎における膵臓の灌流状態の変化の特徴が明らかになったことは、現在進行中の膵炎の臨床例での解析に向けてその礎を築くことができた。臨床例での解析結果も実験膵炎と同様の結果が得られ、本年6月のアメリカ獣医内科学会で発表する予定である。加えて、左心房機能に着目した心エコー図検査による新たな心機能評価法の確立を目指し、正常犬の左心房面積の時相による変化を解析して正常値を確立するとともに、本手法の再現性を明らかにした(Am J Vet Res, 74:864-869)。
    文部科学省, 基盤研究(C), 北海道大学, 研究代表者, 競争的資金, 23580436
  • 冬眠動物における腸内細菌叢と腸粘膜バリア:新しい共生様式の解明
    科学研究費助成事業 挑戦的萌芽研究
    2011年 - 2012年
    園山 慶; 坪田 敏男; 滝口 満喜
    冬眠動物における腸内細菌の制御と腸粘膜バリアについて解析した。シリアンハムスターの冬眠個体では小腸管腔内の分泌抗体濃度が高く、感染防御に貢献している可能性が考えられた。実際、冬眠ハムスターでは腸間膜リンパ節への細菌の移行は認められなかった。また免疫組織におけるリンパ球プロファイルの解析の結果、冬眠期においても消化管粘膜における感染防御機能および免疫制御機能が維持されていると推察された。さらに、冬眠ハムスターの小腸粘膜上皮における細胞更新が著しく遅滞しており、それにより細胞寿命の延長にともなう細胞老化が生じていることが推察された。
    日本学術振興会, 挑戦的萌芽研究, 北海道大学, 23659119
  • 冬眠動物における腸内細菌叢と腸粘膜バリア:新しい共生様式の解明
    科学研究費補助金(挑戦的萌芽研究)
    2011年 - 2012年
    園山 慶; 坪田 敏男; 滝口 満喜
    冬眠動物における腸内細菌の制御と腸粘膜バリアについて解析した。シリアンハムスターの冬眠個体では小腸管腔内の分泌抗体濃度が高く、感染防御に貢献している可能性が考えられた。実際、冬眠ハムスターでは腸間膜リンパ節への細菌の移行は認められなかった。また免疫組織におけるリンパ球プロファイルの解析の結果、冬眠期においても消化管粘膜における感染防御機能および免疫制御機能が維持されていると推察された。さらに、冬眠ハムスターの小腸粘膜上皮における細胞更新が著しく遅滞しており、それにより細胞寿命の延長にともなう細胞老化が生じていることが推察された。
    文部科学省, 挑戦的萌芽研究, 北海道大学, 連携研究者, 競争的資金, 23659119
  • 膜透過性ペプチド融合アポトーシス誘導タンパク質を用いた新規放射線がん治療
    科学研究費助成事業 挑戦的萌芽研究
    2009年 - 2010年
    稲波 修; 滝口 満喜; 山盛 徹
    本研究では、p34^-サイクリンB1によるリン酸化部位である34番目のスレオニン(T)をアラニン(A)へ置換したT34A変異サバイビンのN末端に膜透過性ペプチドTAT配列を付加した融合蛋白質を作成し、腫瘍治療におけるTATペプチドによる蛋白質導入技術の有効性と、T34A変異サバイビンのcolon26マウス移植固形腫瘍モデルへの局所投与と放射線照射の併用による抗腫瘍効果について検討した。TATペプチドを付加したサバイビン蛋白質は、腫瘍組織への直接投与で、短時間に腫瘍細胞内へ導入された。X線2Gyの単独照射は、有意な腫瘍の増殖遅延を示さなかった。また、TAT融合T34A変異サバイビンの腫瘍細胞への単独投与も、有意な増殖遅延を示さなかった。一方、X線2GyとTAT融合T34A変異サバイビンの併用は顕著な増殖遅延を示した。組織学的な検索によりX線2GyとTAT融合T34A変異サバイビンの併用による抗腫瘍効果はアポトーシスの誘導によるものであることが示された。さらに、併用により腫瘍組織中の増殖細胞数の減少が観察されたことより、アポトーシス誘導は増殖細胞に特異的に起こることが示唆された。細胞周期関連蛋白質の検出から放射線照射によるG2/M期停止が示唆された。これらの結果から、TAT融合T34A変異サバイビンとX線2Gyの併用による抗腫瘍効果はX線照射で生じる細胞周期チェックポイントに関連したT34A変異サバイビンによるアポトーシス誘導の増強であると考えられた。以上の結果から、TATペプチドによる蛋白質導入技術が腫瘍治療において有効であり、T34A変異サバイビンの投与は腫瘍の放射線治療において、放射線による抗腫瘍作用を増強することが明らかにされた。
    日本学術振興会, 挑戦的萌芽研究, 北海道大学, 21658106
  • 膜透過性ペプチド融合アポトーシス誘導タンパク質を用いた新規放射線がん治療
    科学研究費補助金(挑戦的萌芽研究)
    2009年 - 2010年
    稲波 修; 滝口 満喜; 山盛 徹
    本研究では、p34^-サイクリンB1によるリン酸化部位である34番目のスレオニン(T)をアラニン(A)へ置換したT34A変異サバイビンのN末端に膜透過性ペプチドTAT配列を付加した融合蛋白質を作成し、腫瘍治療におけるTATペプチドによる蛋白質導入技術の有効性と、T34A変異サバイビンのcolon26マウス移植固形腫瘍モデルへの局所投与と放射線照射の併用による抗腫瘍効果について検討した。TATペプチドを付加したサバイビン蛋白質は、腫瘍組織への直接投与で、短時間に腫瘍細胞内へ導入された。X線2Gyの単独照射は、有意な腫瘍の増殖遅延を示さなかった。また、TAT融合T34A変異サバイビンの腫瘍細胞への単独投与も、有意な増殖遅延を示さなかった。一方、X線2GyとTAT融合T34A変異サバイビンの併用は顕著な増殖遅延を示した。組織学的な検索によりX線2GyとTAT融合T34A変異サバイビンの併用による抗腫瘍効果はアポトーシスの誘導によるものであることが示された。さらに、併用により腫瘍組織中の増殖細胞数の減少が観察されたことより、アポトーシス誘導は増殖細胞に特異的に起こることが示唆された。細胞周期関連蛋白質の検出から放射線照射によるG2/M期停止が示唆された。これらの結果から、TAT融合T34A変異サバイビンとX線2Gyの併用による抗腫瘍効果はX線照射で生じる細胞周期チェックポイントに関連したT34A変異サバイビンによるアポトーシス誘導の増強であると考えられた。以上の結果から、TATペプチドによる蛋白質導入技術が腫瘍治療において有効であり、T34A変異サバイビンの投与は腫瘍の放射線治療において、放射線による抗腫瘍作用を増強することが明らかにされた。
    文部科学省, 挑戦的萌芽研究, 北海道大学, 連携研究者, 競争的資金, 21658106
  • 自己免疫性唾液線炎におけるB細胞異常増殖の原因遺伝子群と遺伝子間相互作用
    科学研究費助成事業 基盤研究(C)
    2006年 - 2008年
    滝口 満喜; 今野 明弘; 滝口 満善
    シェーグレン症候群(Sjogren's syndrome ; SS)モデルIQIマウスにおけるB細胞優勢の下顎腺炎(B細胞性下顎腺炎)を遺伝学的に解析した。その結果、B細胞性下顎腺炎の量的形質遺伝子座(QTL)は少なくとも3個有り、単独で効果を発揮する主要QTL(autoimmune sialitis in IQImice, associated locus 1 ; Asq1)が第6染色体前端に、Asq1の効果を増強するエピスタシスQTLが第3染色体後方(Asq2)に、また、逆にAsq1の効果を抑制する抵抗性遺伝子座が第1染色体後方(Asq3)に位置することを明らかになった。Asq1の1LOD区間内に位置するIca1に注目し、そのcDNA塩基配列を対照C57BL/6(B6)と比較した結果、IQI-B6間で6個の一塩基多型があり、2個のアミノ酸多型が生じていた。また、ウエスタンブロット法では、IQエマウスの血清中に抗Ica1自己抗体の存在を示すバンドカミ検出された。以上の結果より、IQIマウスにおいて、Ica1に対するB細胞自己免疫が成立していることが明らかになり、原因として、1ca1の塩基多型の可能性が挙げられた。
    日本学術振興会, 基盤研究(C), 北海道大学, 18580286
  • 自己免疫疾患の新しい分子機構論:中枢性トレランスの破綻による自己への攻撃
    科学研究費助成事業 基盤研究(C)
    2005年 - 2006年
    滝口 満喜; 谷山 弘行; 今野 明弘
    高次生体における免疫システムは、外来抗原に対して排除応答を示すが自己抗原に対しては応答しない。この抗原特異的に不応答を示すトレランスは免疫系の重要な特徴で、自己抗原に対するトレランスの破綻は、免疫系による生体自己組織への攻撃と破壊すなわち自己免疫疾患をもたらす。申請者らは、代表的な自己免疫疾患であるシェーグレン症候群(SS)のモデルマウスであるIQI/JicマウスではSSに特徴的な涙腺炎や唾液腺炎などに加え、加齢に伴い膵臓、腎臓、肺などに病変が拡大することを示すとともに、その原因となる自己抗原が臓器特異的なカリクレイン(Klk)13であることをつきとめた。さらに、その発症における末梢性トレランスの関与を調べる目的で、生後3日目に胸腺を摘出して末梢性トレランスを担う制御性T細胞を除外したところ、唾液腺の病変に変化が見られなかったことから、本マウスのSS様病変の形成は末梢性トレランスの破綻によるものではないことを示した。また本マウスではマイトージェン刺激に対するIL-2の産生が顕著に低下しており、これがIL-2遺伝子発現の低下に起因することを確認した。IL-2はin vivoにおいて自己抗原に対する免疫寛容の維持に重要な役割を果たしていることが知られており、これらの結果からT細胞活性化に伴うIL-2の産生低下が本マウスにおける自己寛容の破綻を引き起こし、自己免疫疾患の発症に直接関与している可能性が考えられた。本研究の結果をまとめると、IQI/JicマウスではT細胞の活性化に伴うIL-2産生不全が制御性T細胞とは異なる自己寛容機構を破綻させ、制御性T細胞に依存しない自己寛容の破綻がKlk-13を含む自己抗原に対する持続的な自己反応性T細胞の活性化を引き起こし、唾液腺から他の標的臓器への炎症波及に関与して全身病態の形成に重要な役割を果たすと考えられた。
    日本学術振興会, 基盤研究(C), 酪農学園大学, 17580282
  • 自己免疫疾患の新しい分子機構論:中枢性トレランスの破綻による自己への攻撃
    科学研究費補助金(基盤研究(C))
    2005年 - 2006年
    滝口 満喜; 谷山 弘行; 今野 明弘
    高次生体における免疫システムは、外来抗原に対して排除応答を示すが自己抗原に対しては応答しない。この抗原特異的に不応答を示すトレランスは免疫系の重要な特徴で、自己抗原に対するトレランスの破綻は、免疫系による生体自己組織への攻撃と破壊すなわち自己免疫疾患をもたらす。申請者らは、代表的な自己免疫疾患であるシェーグレン症候群(SS)のモデルマウスであるIQI/JicマウスではSSに特徴的な涙腺炎や唾液腺炎などに加え、加齢に伴い膵臓、腎臓、肺などに病変が拡大することを示すとともに、その原因となる自己抗原が臓器特異的なカリクレイン(Klk)13であることをつきとめた。さらに、その発症における末梢性トレランスの関与を調べる目的で、生後3日目に胸腺を摘出して末梢性トレランスを担う制御性T細胞を除外したところ、唾液腺の病変に変化が見られなかったことから、本マウスのSS様病変の形成は末梢性トレランスの破綻によるものではないことを示した。また本マウスではマイトージェン刺激に対するIL-2の産生が顕著に低下しており、これがIL-2遺伝子発現の低下に起因することを確認した。IL-2はin vivoにおいて自己抗原に対する免疫寛容の維持に重要な役割を果たしていることが知られており、これらの結果からT細胞活性化に伴うIL-2の産生低下が本マウスにおける自己寛容の破綻を引き起こし、自己免疫疾患の発症に直接関与している可能性が考えられた。本研究の結果をまとめると、IQI/JicマウスではT細胞の活性化に伴うIL-2産生不全が制御性T細胞とは異なる自己寛容機構を破綻させ、制御性T細胞に依存しない自己寛容の破綻がKlk-13を含む自己抗原に対する持続的な自己反応性T細胞の活性化を引き起こし、唾液腺から他の標的臓器への炎症波及に関与して全身病態の形成に重要な役割を果たすと考えられた。
    文部科学省, 基盤研究(C), 酪農学園大学, 研究代表者, 競争的資金, 17580282
  • 特定領域研究「動物疾患ジェノミクス」新規創設を目指す企画と調査
    科学研究費助成事業 基盤研究(C)
    2004年 - 2004年
    稲葉 睦; 小川 博之; 国枝 哲夫; 鈴木 勝士; 北川 均; 滝口 満喜
    1)学術雑誌等の調査により、過去40年間に国内外で報告された動物の遺伝性疾患、ならびに動物のゲノム解析について、その内容と現在の研究動向を検討した。その概要は、獣医学教科書である「獣医内科学」等に記載のほか、獣医臨床遺伝研究会(平成17年3月)、獣医学会学術集会シンポジウム(平成17年4月)、ならびにHP(平成17年5月開設予定)にて報告する。
    2)総括班、調整班が4回の討議を行い、上記を含め以下の合意に達した。
    ◆対象とする疾患:特に国内で問題となっている、あるいは特徴的な疾患で、その解析が、産業動物の損耗防止や分子育種につながる牛・豚の疾患、人間社会との共存や福祉の向上に資する犬・猫の疾患、生命科学や基礎医学の基礎理論構築、医療への応用に発展し得る動物疾患。
    ◆研究の展開:(1)特定の単一遺伝子疾患の原因遺伝子異常の解析、ならびに発症の分子機構とそれに基づく分子の生理機能の解明。(2)多因子疾患臨床症例の詳細な病態分類と原因となる分子・遺伝子異常の探索。
    ◆研究組織:特定領域研究の創設に際しては、臨床知見の集積を含めた研究内容の特性に鑑みて5年間程度の研究展開を目指す。総括班、調整班のもとに上記(1)と(2)の研究展開の基盤となる2〜3の計画研究班を設置して重点的に基礎研究を実施するほか、2年間の公募研究をそれぞれ20件程度ずつ採用する。
    2)下記の研究集会、公開シンポジウムを開催し、動物遺伝性疾患概念の周知と研究者-臨床獣医師間交流等を図った。
    ◆「近未来の小動物医療-分子医学の潮流-」平成16年9月(札幌)Dr.U.Giger (Univ.Pennsylvania)ら講師4名、参加者約200名。
    ◆「臨床遺伝研究会・農水事業・科研費ジョイントフォーラム」平成17年3月(天童)講演者延べ25名、参加者約80名。
    これらをもとに、特定領域研究等の具体化を進める。
    日本学術振興会, 基盤研究(C), 北海道大学, 16638008
  • 特定領域研究「動物疾患ジェノミクス」新規創設を目指す企画と調査
    科学研究費補助金(基盤研究(C))
    2004年 - 2004年
    稲葉 睦; 小川 博之; 国枝 哲夫; 鈴木 勝士; 北川 均; 滝口 満喜
    1)学術雑誌等の調査により、過去40年間に国内外で報告された動物の遺伝性疾患、ならびに動物のゲノム解析について、その内容と現在の研究動向を検討した。その概要は、獣医学教科書である「獣医内科学」等に記載のほか、獣医臨床遺伝研究会(平成17年3月)、獣医学会学術集会シンポジウム(平成17年4月)、ならびにHP(平成17年5月開設予定)にて報告する。2)総括班、調整班が4回の討議を行い、上記を含め以下の合意に達した。◆対象とする疾患:特に国内で問題となっている、あるいは特徴的な疾患で、その解析が、産業動物の損耗防止や分子育種につながる牛・豚の疾患、人間社会との共存や福祉の向上に資する犬・猫の疾患、生命科学や基礎医学の基礎理論構築、医療への応用に発展し得る動物疾患。◆研究の展開:(1)特定の単一遺伝子疾患の原因遺伝子異常の解析、ならびに発症の分子機構とそれに基づく分子の生理機能の解明。(2)多因子疾患臨床症例の詳細な病態分類と原因となる分子・遺伝子異常の探索。◆研究組織:特定領域研究の創設に際しては、臨床知見の集積を含めた研究内容の特性に鑑みて5年間程度の研究展開を目指す。総括班、調整班のもとに上記(1)と(2)の研究展開の基盤となる2〜3の計画研究班を設置して重点的に基礎研究を実施するほか、2年間の公募研究をそれぞれ20件程度ずつ採用する。2)下記の研究集会、公開シンポジウムを開催し、動物遺伝性疾患概念の周知と研究者-臨床獣医師間交流等を図った。◆「近未来の小動物医療-分子医学の潮流-」平成16年9月(札幌)Dr.U.Giger (Univ.Pennsylvania)ら講師4名、参加者約200名。◆「臨床遺伝研究会・農水事業・科研費ジョイントフォーラム」平成17年3月(天童)講演者延べ25名、参加者約80名。これらをもとに、特定領域研究等の具体化を進める。
    文部科学省, 基盤研究(C), 北海道大学, 連携研究者, 競争的資金, 16638008
  • 組織の破壊と低形成-細胞間ジャンクションの分子構築破綻と疾患の遺伝的基盤-
    科学研究費助成事業 萌芽研究
    2003年 - 2004年
    滝口 満喜; 稲葉 睦; 田島 誉士; 高桑 雄一
    本研究は、上皮や実質組織の破壊や低形成をともなう多彩な動物疾患の臨床知見の集積と分子病態解析の成果から派生したアイディアに基づくものである。本計画は、"細胞間接合の遺伝的異常と疾患"という新しい観点から、従来、遺伝性素因の存在を疑われながら病因のとらえどころがなかった組織破壊を伴う疾患や臓器低形成の分子機構を解明することを将来目標としている。本萌芽研究では、上記仮説実証の第一歩として、タイトジャンクション(TJ)に分布するCL分子ファミリーに焦点を絞り、まず正常組織における分子群の臓器、組織分布を明らかにし、次いで腎、肝、消化管、皮膚の組織破壊、あるいは低形成を呈する臨床例におけるCL分子の異常を検証することを目的とした。クローディン(CL)分子ファミリーは現在までにヒト、マウスでいずれもCL-1〜CL-18までの18分子種が知られている。代表者らは、これまで牛CL-16に関する解析を行ってきたが、本研究計画では小動物(犬と猫)を対象とするため、まずこれら18種のCLを各々同定するためのツールとして特異抗体を作製することから着手した。犬、猫、個々のCL分子にそれぞれ対応する抗体を作製するのは煩雑であり、また交差性が期待されるため、まず犬CLsに対する抗体を作出、必要に応じて抗猫CLs抗体を作製することとした。抗原として用いる各CL分子C末端ペプチド(C末端の細胞質ドメイン30-40アミノ酸残基)を調製するために、各CL分子のcDNAをRACE法で単離し、GST-融合タンパク質ベクターにクローン化した。cDNA単離に利用する臓器、あるいはプライマーはヒトでの知見に基づいた。GST-融合タンパク質として得た各分子から必要なC末端ペプチドを精製し、ウサギに免疫して、アフィニティー精製によって特異抗体を得た。次いで、イムノブロッティング、ならびに正常組織を用いた蛍光抗体法で反応性と特異性を検定した。臨床例を用いた検討では、様々な疾患でCL分子の局在や発現量に変化が認められたが、現時点では疾患特異的に変動する分子の特定には至らず、今後、さらなる解析が必要である。
    日本学術振興会, 萌芽研究, 15658096
  • 組織の破壊と低形成-細胞間ジャンクションの分子構築破綻と疾患の遺伝的基盤-
    科学研究費補助金(萌芽研究)
    2003年 - 2004年
    滝口 満喜; 高桑 雄一; 田島 誉士; 稲葉 睦
    本研究は、上皮や実質組織の破壊や低形成をともなう多彩な動物疾患の臨床知見の集積と分子病態解析の成果から派生したアイディアに基づくものである。本計画は、"細胞間接合の遺伝的異常と疾患"という新しい観点から、従来、遺伝性素因の存在を疑われながら病因のとらえどころがなかった組織破壊を伴う疾患や臓器低形成の分子機構を解明することを将来目標としている。本萌芽研究では、上記仮説実証の第一歩として、タイトジャンクション(TJ)に分布するCL分子ファミリーに焦点を絞り、まず正常組織における分子群の臓器、組織分布を明らかにし、次いで腎、肝、消化管、皮膚の組織破壊、あるいは低形成を呈する臨床例におけるCL分子の異常を検証することを目的とした。クローディン(CL)分子ファミリーは現在までにヒト、マウスでいずれもCL-1〜CL-18までの18分子種が知られている。代表者らは、これまで牛CL-16に関する解析を行ってきたが、本研究計画では小動物(犬と猫)を対象とするため、まずこれら18種のCLを各々同定するためのツールとして特異抗体を作製することから着手した。犬、猫、個々のCL分子にそれぞれ対応する抗体を作製するのは煩雑であり、また交差性が期待されるため、まず犬CLsに対する抗体を作出、必要に応じて抗猫CLs抗体を作製することとした。抗原として用いる各CL分子C末端ペプチド(C末端の細胞質ドメイン30-40アミノ酸残基)を調製するために、各CL分子のcDNAをRACE法で単離し、GST-融合タンパク質ベクターにクローン化した。cDNA単離に利用する臓器、あるいはプライマーはヒトでの知見に基づいた。GST-融合タンパク質として得た各分子から必要なC末端ペプチドを精製し、ウサギに免疫して、アフィニティー精製によって特異抗体を得た。次いで、イムノブロッティング、ならびに正常組織を用いた蛍光抗体法で反応性と特異性を検定した。臨床例を用いた検討では、様々な疾患でCL分子の局在や発現量に変化が認められたが、現時点では疾患特異的に変動する分子の特定には至らず、今後、さらなる解析が必要である。
    文部科学省, 萌芽研究, 北海道大学->酪農学園大学, 研究代表者, 競争的資金, 15658096
  • 犬の自然発生悪性腫瘍を用いた血管新生阻害と分化誘導による腫瘍休眠療法の臨床試験
    科学研究費助成事業 基盤研究(B)
    2002年 - 2004年
    廉澤 剛; 滝口 満喜; 落合 謙爾; 笠岡 達彦; 大泉 巌雄; 日下 雅美; 日下 雅実
    悪性腫瘍が自然発生した犬に、血管新生阻害剤TNP-470とサリドマイド、および分化誘導剤OCTを投与し、これらの薬剤の副作用をおもに調べ、さらに可能な範囲で抗腫瘍効果について調べた。
    TNP-470は、1回あたり12.5〜223mg/m^2の量で、皮下あるいは静脈内に週1〜3回の割合で投与した。この研究薬は47症例に使用し、副作用と考えられる徴候として、ふらつきあるいは震えが9症例に認められ、次いでけいれん発作が4症例に、出血、食欲低下および嘔吐がそれぞれ1症例に認められた。
    サリドマイドは、1回あたり5.0〜20mg/kgの量で毎日経口投与した。この研究薬は、23症例に投与され、副作用と考えられる徴候として、ふらつき、沈鬱あるいは便の軟化が6症例に認められた。
    OCTは、1回あたり0.03〜0.12μg/kgの量で毎日経口投与した。この研究薬は、31症例に投与されたが、2週以上にわたり投与された21症例中7症例に高Ca血症が認められた。高Ca血症は休薬によって1週以内に正常に復した。いずれの薬剤においても、副作用と血液検査の変化に重篤なものはなかった。
    抗腫瘍効果に関しては、比較対照がないため腫瘍の成長速度や遠隔転移率を抑制しているかを明らかにすることは難しかったが、いくつかの症例で原発巣あるいは転移巣に縮小が認められた。また、高率に転移が生じる骨肉腫などの症例においては、長期にわたって転移が生じない症例も認められた。
    以上のことから、今回用いた血管新生阻害剤と分化誘導剤は、従来の抗癌剤と比較して重篤な副作用は極めて少なく、また腫瘍が縮小する症例を認めたことから、腫瘍休眠療法を目指す治療薬としてさらに検討する価値が大きいと思われた。
    日本学術振興会, 基盤研究(B), 14360183
  • 犬の自然発生悪性腫瘍を用いた血管新生阻害と分化誘導による腫瘍休眠療法の臨床試験
    科学研究費補助金(基盤研究(B))
    2002年 - 2004年
    廉澤 剛; 日下 雅実; 笠岡 達彦; 落合 謙爾; 滝口 満喜; 大泉 巌雄; 日下 雅美
    悪性腫瘍が自然発生した犬に、血管新生阻害剤TNP-470とサリドマイド、および分化誘導剤OCTを投与し、これらの薬剤の副作用をおもに調べ、さらに可能な範囲で抗腫瘍効果について調べた。TNP-470は、1回あたり12.5〜223mg/m^2の量で、皮下あるいは静脈内に週1〜3回の割合で投与した。この研究薬は47症例に使用し、副作用と考えられる徴候として、ふらつきあるいは震えが9症例に認められ、次いでけいれん発作が4症例に、出血、食欲低下および嘔吐がそれぞれ1症例に認められた。サリドマイドは、1回あたり5.0〜20mg/kgの量で毎日経口投与した。この研究薬は、23症例に投与され、副作用と考えられる徴候として、ふらつき、沈鬱あるいは便の軟化が6症例に認められた。OCTは、1回あたり0.03〜0.12μg/kgの量で毎日経口投与した。この研究薬は、31症例に投与されたが、2週以上にわたり投与された21症例中7症例に高Ca血症が認められた。高Ca血症は休薬によって1週以内に正常に復した。いずれの薬剤においても、副作用と血液検査の変化に重篤なものはなかった。抗腫瘍効果に関しては、比較対照がないため腫瘍の成長速度や遠隔転移率を抑制しているかを明らかにすることは難しかったが、いくつかの症例で原発巣あるいは転移巣に縮小が認められた。また、高率に転移が生じる骨肉腫などの症例においては、長期にわたって転移が生じない症例も認められた。以上のことから、今回用いた血管新生阻害剤と分化誘導剤は、従来の抗癌剤と比較して重篤な副作用は極めて少なく、また腫瘍が縮小する症例を認めたことから、腫瘍休眠療法を目指す治療薬としてさらに検討する価値が大きいと思われた。
    文部科学省, 基盤研究(B), 北海道大学->酪農学園大学, 連携研究者, 競争的資金, 14360183
  • 赤芽球系分化における膜骨格構築"ユニット工法仮説"の時空間分解分子機構論
    科学研究費助成事業 基盤研究(B)
    2002年 - 2003年
    稲葉 睦; 高桑 雄一; 斉藤 昌之; 前出 吉光; 稲波 修; 山本 雅之; 滝口 満喜
    本研究は、赤芽球系細胞における赤血球膜骨格組み込みの"ユニット工法仮説"実証を目的とする。骨髄赤芽球系細胞、赤芽球系培養細胞を用い、遺伝子導入とタンパク質の生化学的・形態学的解析で以下の成果を得た。
    ●赤芽球系培養細胞K562を用いて、膜骨格と相互作用する主要膜タンパク質、バンド3、グライコフォリンC、アンキリン、プロテイン4.1、ならびにそれらの変異体の安定発現系を構築し、細胞内局在と赤芽球分化誘導時の挙動や細胞分化・増殖に及ぼす影響を検討した。膜内在性であるバンド3とグライコフォリンCはともにER/Golgiを経て細胞膜に移行した。これらと膜骨格を連結すると考えられるアンキリンとプロテイン4.1も同様にERとGolgiに局在が認められ、これは赤芽球系分化誘導後にも変化しなかった。また、内因性のアンキリンやプロテイン4.1、さらにスペクトリンも主にER/Golgiに分布が認められた。したがって、膜骨格組み込みは赤芽球系細胞の細胞膜ではなく、ERで生じる現象であることが明らかになった。
    ●同様の解析で、K562細胞におけるバンド3分子の恒常的発現により細胞増殖速度が約70%に低下すること、誘導剤による赤芽球系分化速度も低下する現象が見出された。しかし、誘導可能な赤芽球までのステージでは、細胞骨格タンパク質の局在や細胞形態に対する影響は認められなかった。
    ●骨髄赤芽球系前駆細胞ではスペクトリン等の膜骨格タンパク質の合成とER/Golgiと思われる膜画分への移行がまず生じ、次いでバンド3等の合成と細胞膜での発現が観察された。膜骨格タンパク質の分布は脱核前後で急激に変化した。
    以上のように、本研究からは、膜骨格タンパク質の組み込みが細胞内小器官の膜上で既に生じることが明らかになった。ただし、その細胞膜への移行がいわゆる小胞輸送による"ユニット"としてか否かの検証には、新たな手段を講じる必要がある。
    日本学術振興会, 基盤研究(B), 北海道大学, 14360187
  • 膜タンパク質のポストゴルジ/ERレトリーバル小胞輸送における新規分子機構の構築
    科学研究費助成事業 萌芽研究
    2002年 - 2003年
    稲葉 睦; 高桑 雄一; 滝口 満喜
    本研究の目的は、牛グライコフォリンC(GP-C)の発現、遺伝子型-表現型連関について従来得た以下の仮説を検証し、S85によるポストゴルジ膜移行、あるいはERレトリーバル制御の分子機構を解明することを目的とする。
    <仮説1>S85のリン酸化等の翻訳後修飾がポストゴルジ膜移行を決定づける未知のシグナルとして機能している。あるいは、<仮説2>S85を含む周辺配列が未知の膜移行認識シグナルとなっている。仮説1との相乗作用もあり得る。
    1.仮説1を検証するために、GST-fused GP-C(C末端細胞質ドメイン)を調製し、これを基質とするProtein kinaseを解析した。その結果、Casein kinase I (CKI)がGP-CのC-末端細胞質ドメインをリン酸化することが判明した。CKIは、遺伝子多型であるS85、N85のGP-Cの両者をリン酸化することから、S85以外のSer/Thr残基もリン酸化されることが推定された。
    2.COS細胞、K562細胞におけるGP-C発現系を構築し、それらのリン酸化動態と細胞膜への移行を解析した。これらの細胞ではGP-Cのリン酸化が観察されたが、少なくともCKI阻害剤存在下でのリン酸化の程度は対照と、あるいはGP-CS85とN85とで相違なく、また細胞膜移行の程度にも顕著な差は認められなかった。
    3.翻訳後修飾としてO-GlcNAc付加を推定し、その検証を行ったが、O-GlcNAc存在は検出されなかった。
    4.仮説2を検証するためにS85を中心にC末端細胞質ドメインのアミノ酸残基を欠く変異体を作製し、培養細胞に導入してその膜移行を解析したところ、むしろにC末端領域を欠く変異体の膜移行が低下することが判明した。これら変異体は、ERに留まり分解除去を受けた。
    日本学術振興会, 萌芽研究, 北海道大学, 14656134
  • 膜タンパク質のポストゴルジ/ERレトリーバル小胞輸送における新規分子機構の構築
    科学研究費補助金(萌芽研究)
    2002年 - 2003年
    稲葉 睦; 高桑 雄一; 滝口 満喜
    本研究の目的は、牛グライコフォリンC(GP-C)の発現、遺伝子型-表現型連関について従来得た以下の仮説を検証し、S85によるポストゴルジ膜移行、あるいはERレトリーバル制御の分子機構を解明することを目的とする。<仮説1>S85のリン酸化等の翻訳後修飾がポストゴルジ膜移行を決定づける未知のシグナルとして機能している。あるいは、<仮説2>S85を含む周辺配列が未知の膜移行認識シグナルとなっている。仮説1との相乗作用もあり得る。1.仮説1を検証するために、GST-fused GP-C(C末端細胞質ドメイン)を調製し、これを基質とするProtein kinaseを解析した。その結果、Casein kinase I (CKI)がGP-CのC-末端細胞質ドメインをリン酸化することが判明した。CKIは、遺伝子多型であるS85、N85のGP-Cの両者をリン酸化することから、S85以外のSer/Thr残基もリン酸化されることが推定された。2.COS細胞、K562細胞におけるGP-C発現系を構築し、それらのリン酸化動態と細胞膜への移行を解析した。これらの細胞ではGP-Cのリン酸化が観察されたが、少なくともCKI阻害剤存在下でのリン酸化の程度は対照と、あるいはGP-CS85とN85とで相違なく、また細胞膜移行の程度にも顕著な差は認められなかった。3.翻訳後修飾としてO-GlcNAc付加を推定し、その検証を行ったが、O-GlcNAc存在は検出されなかった。4.仮説2を検証するためにS85を中心にC末端細胞質ドメインのアミノ酸残基を欠く変異体を作製し、培養細胞に導入してその膜移行を解析したところ、むしろにC末端領域を欠く変異体の膜移行が低下することが判明した。これら変異体は、ERに留まり分解除去を受けた。
    文部科学省, 萌芽研究, 東京大学->北海道大学, 連携研究者, 競争的資金, 14656134
  • 赤芽球系分化における膜骨格構築"ユニット工法仮説"の時空間分解分子機構論
    科学研究費補助金(基盤研究(B))
    2002年 - 2003年
    稲葉 睦; 滝口 満喜; 稲波 修; 前出 吉光; 山本 雅之; 高桑 雄一; 斉藤 昌之
    本研究は、赤芽球系細胞における赤血球膜骨格組み込みの"ユニット工法仮説"実証を目的とする。骨髄赤芽球系細胞、赤芽球系培養細胞を用い、遺伝子導入とタンパク質の生化学的・形態学的解析で以下の成果を得た。●赤芽球系培養細胞K562を用いて、膜骨格と相互作用する主要膜タンパク質、バンド3、グライコフォリンC、アンキリン、プロテイン4.1、ならびにそれらの変異体の安定発現系を構築し、細胞内局在と赤芽球分化誘導時の挙動や細胞分化・増殖に及ぼす影響を検討した。膜内在性であるバンド3とグライコフォリンCはともにER/Golgiを経て細胞膜に移行した。これらと膜骨格を連結すると考えられるアンキリンとプロテイン4.1も同様にERとGolgiに局在が認められ、これは赤芽球系分化誘導後にも変化しなかった。また、内因性のアンキリンやプロテイン4.1、さらにスペクトリンも主にER/Golgiに分布が認められた。したがって、膜骨格組み込みは赤芽球系細胞の細胞膜ではなく、ERで生じる現象であることが明らかになった。●同様の解析で、K562細胞におけるバンド3分子の恒常的発現により細胞増殖速度が約70%に低下すること、誘導剤による赤芽球系分化速度も低下する現象が見出された。しかし、誘導可能な赤芽球までのステージでは、細胞骨格タンパク質の局在や細胞形態に対する影響は認められなかった。●骨髄赤芽球系前駆細胞ではスペクトリン等の膜骨格タンパク質の合成とER/Golgiと思われる膜画分への移行がまず生じ、次いでバンド3等の合成と細胞膜での発現が観察された。膜骨格タンパク質の分布は脱核前後で急激に変化した。以上のように、本研究からは、膜骨格タンパク質の組み込みが細胞内小器官の膜上で既に生じることが明らかになった。ただし、その細胞膜への移行がいわゆる小胞輸送による"ユニット"としてか否かの検証には、新たな手段を講じる必要がある。
    文部科学省, 基盤研究(B), 東京大学->北海道大学, 連携研究者, 競争的資金, 14360187
  • アポトーシス増強に着目した制癌剤の開発と獣医臨床応用
    科学研究費助成事業 基盤研究(C)
    2000年 - 2001年
    稲波 修; 滝口 満喜; 松田 彰; 桑原 幹典
    本研究は、アポトーシスによる細胞死を効率的に引き起こすことを目指したヌクレオシド系増感剤を開発し、獣医領域で問題となるネコ白血病、イヌリンパ腫などの治療のための制がん剤の開発を目的とする。モデル細胞としてヒト胃癌細胞MKN-45細胞とMOLT-4細胞の制がん剤による細胞死の機構を検討した。制がん剤としては1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine(Ecyd)と2'-chrolo-deoxyadenosine(Cl-dAde)を化学合成し、それぞれ検討した。その結果、両細胞ともそれぞれの制がん剤でカスパーゼファミリーの活性化を伴うアポトーシスを効率よく引き起こすことが明らかとなった。そのメカニズムには細胞によって差があり、MKN-45細胞についてはp53依存性のアポトーシスであり、MOLT-4の場合はp53非依存性、Fas活性化依存性のアポトーシスであることが明らかとなった。MKN-45細胞の場合は、蛋白合成に非依存性のカスパーゼ3依存性のアポトーシスを、MOLT-4細胞の場合は、アポトーシス誘導に蛋白質合成を必要とし、FASの活性化、カスパーゼ8を活性化し、カスパーゼ3に依存するアポトーシスを引き起こすことが明らかとなった。この結果は、細胞の種類に依存してアポトーシスを引き起こすシグナル経路の違いを意味している。また、単独では細胞死を起こさない量のEcydで処理した細胞は、放射線照射によって、効率よくネクローシスをアポトーシスに変換できることも明らかとなった。そのメカニズムとして放射線誘発G2期停止のECydによる解除作用が重要であり、G2期解除に伴ってアポトーシスが誘導されることが明かとなった。動物癌細胞への応用という点では、イヌリンパ腫由来CL細胞で、あるいはネコ白血病由来末梢リンパ球でもこれらの薬剤は有用であることが確かめられた。以上の結果は放射線や制癌剤による獣医臨床応用において重要な知見である。
    日本学術振興会, 基盤研究(C), 北海道大学, 12660266
  • アポトーシス増強に着目した制癌剤の開発と獣医臨床応用
    科学研究費補助金(基盤研究(C))
    2000年 - 2001年
    稲波 修; 滝口 満喜; 松田 彰; 桑原 幹典
    本研究は、アポトーシスによる細胞死を効率的に引き起こすことを目指したヌクレオシド系増感剤を開発し、獣医領域で問題となるネコ白血病、イヌリンパ腫などの治療のための制がん剤の開発を目的とする。モデル細胞としてヒト胃癌細胞MKN-45細胞とMOLT-4細胞の制がん剤による細胞死の機構を検討した。制がん剤としては1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine(Ecyd)と2'-chrolo-deoxyadenosine(Cl-dAde)を化学合成し、それぞれ検討した。その結果、両細胞ともそれぞれの制がん剤でカスパーゼファミリーの活性化を伴うアポトーシスを効率よく引き起こすことが明らかとなった。そのメカニズムには細胞によって差があり、MKN-45細胞についてはp53依存性のアポトーシスであり、MOLT-4の場合はp53非依存性、Fas活性化依存性のアポトーシスであることが明らかとなった。MKN-45細胞の場合は、蛋白合成に非依存性のカスパーゼ3依存性のアポトーシスを、MOLT-4細胞の場合は、アポトーシス誘導に蛋白質合成を必要とし、FASの活性化、カスパーゼ8を活性化し、カスパーゼ3に依存するアポトーシスを引き起こすことが明らかとなった。この結果は、細胞の種類に依存してアポトーシスを引き起こすシグナル経路の違いを意味している。また、単独では細胞死を起こさない量のEcydで処理した細胞は、放射線照射によって、効率よくネクローシスをアポトーシスに変換できることも明らかとなった。そのメカニズムとして放射線誘発G2期停止のECydによる解除作用が重要であり、G2期解除に伴ってアポトーシスが誘導されることが明かとなった。動物癌細胞への応用という点では、イヌリンパ腫由来CL細胞で、あるいはネコ白血病由来末梢リンパ球でもこれらの薬剤は有用であることが確かめられた。以上の結果は放射線や制癌剤による獣医臨床応用において重要な知見である。
    文部科学省, 基盤研究(C), 北海道大学, 連携研究者, 競争的資金, 12660266
  • MRL/lprマウスにおける肺病変発症機序の解明
    科学研究費助成事業 奨励研究(A)
    1999年 - 2000年
    滝口 満喜
    本研究の目的は、MRL/lprマウスにおけるCD28/CTLA4-B7補助シグナル非依存性の肺病変について、遺伝背景の異なるマウスを用いることで病変形成に関わる原因遺伝子を探索すること、さらに、肺病変発症機序を解明するために、免疫組織化学的および臨床病理学的に詳細に解析して、病変に関わるサイトカインを同定し、抗サイトカイン抗体の投与実験によってその関わりを証明することである。
    まず、MRL/lprに加えて、遺伝背景の異なるC57BL6/lprおよびC3H/He/lprマウスにもCTLA4IgGを生後24時間以内から1回100μg、週3回腹腔内に投与し、20週齢で肺の病理組織学的検索を行った。その結果、MRL/lprではCTLA4IgG投与の有無に関わらず強い肺病変が認められた。C57BL6/lprではCTLA4IgG投与により肺病変が有意に抑制され、C3H/He/lprでは対照と同程度の軽度の単核球浸潤が認められた。以上のことから、CD28/CTLA4-B7補助シグナル非依存性に生じる肺病変は、MRL遺伝背景とともにlpr遺伝子つまり、Fas分子の異常によって誘導されることが示唆された。
    次に、MRL/lprマウスの肺病変発症機序の解明を目的として、MRL/lprマウスの肺組織から単核球を分離し、フローサイトメトリーによる解析を行った。表面抗原の解析から、CTLA4IgG投与によってT細胞の活性化は抑制されたが、マクロファージの活性化は抑制されないことが判明した。また、細胞内サイトカインの解析から、マクロファージからのインターフェロンガンマの産生が抑制されないことが明らかとなった。以上の事から、MRL/lprマウスにおけるCD28/CTLA4-B7補助シグナル非依存性に生じる肺病変の形成には、マクロファージから産生されるインターフェロンガンマが関わっていることが示唆された。
    日本学術振興会, 奨励研究(A), 北海道大学, 11760211
  • MRL/lprマウスにおける肺病変発症機序の解明
    科学研究費補助金(奨励研究(A))
    1999年 - 2000年
    滝口 満喜
    本研究の目的は、MRL/lprマウスにおけるCD28/CTLA4-B7補助シグナル非依存性の肺病変について、遺伝背景の異なるマウスを用いることで病変形成に関わる原因遺伝子を探索すること、さらに、肺病変発症機序を解明するために、免疫組織化学的および臨床病理学的に詳細に解析して、病変に関わるサイトカインを同定し、抗サイトカイン抗体の投与実験によってその関わりを証明することである。まず、MRL/lprに加えて、遺伝背景の異なるC57BL6/lprおよびC3H/He/lprマウスにもCTLA4IgGを生後24時間以内から1回100μg、週3回腹腔内に投与し、20週齢で肺の病理組織学的検索を行った。その結果、MRL/lprではCTLA4IgG投与の有無に関わらず強い肺病変が認められた。C57BL6/lprではCTLA4IgG投与により肺病変が有意に抑制され、C3H/He/lprでは対照と同程度の軽度の単核球浸潤が認められた。以上のことから、CD28/CTLA4-B7補助シグナル非依存性に生じる肺病変は、MRL遺伝背景とともにlpr遺伝子つまり、Fas分子の異常によって誘導されることが示唆された。次に、MRL/lprマウスの肺病変発症機序の解明を目的として、MRL/lprマウスの肺組織から単核球を分離し、フローサイトメトリーによる解析を行った。表面抗原の解析から、CTLA4IgG投与によってT細胞の活性化は抑制されたが、マクロファージの活性化は抑制されないことが判明した。また、細胞内サイトカインの解析から、マクロファージからのインターフェロンガンマの産生が抑制されないことが明らかとなった。以上の事から、MRL/lprマウスにおけるCD28/CTLA4-B7補助シグナル非依存性に生じる肺病変の形成には、マクロファージから産生されるインターフェロンガンマが関わっていることが示唆された。
    文部科学省, 奨励研究(A), 北海道大学, 研究代表者, 競争的資金, 11760211
  • 獣医臨床の診断精度向上に必要な血清・尿中酵素の評価研究
    科学研究費助成事業 基盤研究(C)
    1997年 - 1998年
    安田 準; 滝口 満喜
    獣医臨床における自動分析機器使用を前提とした生化学検査の再評価項目として、血清アルカリフォスファターゼ(ALP)アイソザイムとアデノシンデアミナーゼ(ADA)について検討し、犬や乳牛の肝臓や腫瘍疾患における病態診断の精度が向上した。
    犬の血清ALPアイソザイム分画をレバミゾール活性阻害法によりコルチコステロイド誘発性アイソザイム(CALP)、レクチン沈殿法により骨性アイソザイム(BALP)を定量することにより、肝性アイソザイム(LALP)も計算で求めて、自動分析機器によるALPアイソザイム分画定量法を確立した。ステロイド長期投与犬におけるLALPとCALPの活性変動と肝臓の組織病理学的変化との関係では、肝細胞の空胞変性が軽度の場合はLALP、重度の場合にはLALPとCALPの活性上昇の関与が明らかとなった。
    健康乳牛の血清ADA平均値は5.4IU/lであった。また肉眼的肝臓病変を認めた乳牛の肝臓片と血清とを採取し、肝組織所見とADA値との関連性について検討した。肝組織学的所見を炎症性細胞浸潤の程度で分類し血清ADA活性値を比較したところ、炎症性細胞浸潤の程度が重度である個体ほど高ADA活性を示した。乳牛ではADA特有の病態変動が観察され、肝臓病変の質的な診断意義が示唆された。
    健康犬の血中ADA活性の平均値は血清で4.46IU/l、血漿で4.99IU/lであり有意差は認められなかったが、検体の保存条件による変動が大きく、犬の血中ADAは他の動物に較べて非常に不安定であることが示唆された。腫瘍性疾患の血漿ADA活性値はリンパ腫、白血病、肝腫瘍、髄膜腫などの症例で治療開始前のADA活性に上昇が認められ、化学療法開始後は低下する傾向を示した。1年以上寛解が得られているリンパ腫、肺転移腫瘍、腹腔内腫瘍、肥満細胞腫などでは正常範囲内であり、ADAはリンパ系腫瘍の治療経過を観察する上で、病態の指標となりうることが示唆された。
    日本学術振興会, 基盤研究(C), 北海道大学, 09660335
  • 獣医臨床の診断精度向上に必要な血清・尿中酵素の評価研究
    科学研究費補助金(基盤研究(C))
    1997年 - 1998年
    安田 準; 滝口 満喜
    獣医臨床における自動分析機器使用を前提とした生化学検査の再評価項目として、血清アルカリフォスファターゼ(ALP)アイソザイムとアデノシンデアミナーゼ(ADA)について検討し、犬や乳牛の肝臓や腫瘍疾患における病態診断の精度が向上した。犬の血清ALPアイソザイム分画をレバミゾール活性阻害法によりコルチコステロイド誘発性アイソザイム(CALP)、レクチン沈殿法により骨性アイソザイム(BALP)を定量することにより、肝性アイソザイム(LALP)も計算で求めて、自動分析機器によるALPアイソザイム分画定量法を確立した。ステロイド長期投与犬におけるLALPとCALPの活性変動と肝臓の組織病理学的変化との関係では、肝細胞の空胞変性が軽度の場合はLALP、重度の場合にはLALPとCALPの活性上昇の関与が明らかとなった。健康乳牛の血清ADA平均値は5.4IU/lであった。また肉眼的肝臓病変を認めた乳牛の肝臓片と血清とを採取し、肝組織所見とADA値との関連性について検討した。肝組織学的所見を炎症性細胞浸潤の程度で分類し血清ADA活性値を比較したところ、炎症性細胞浸潤の程度が重度である個体ほど高ADA活性を示した。乳牛ではADA特有の病態変動が観察され、肝臓病変の質的な診断意義が示唆された。健康犬の血中ADA活性の平均値は血清で4.46IU/l、血漿で4.99IU/lであり有意差は認められなかったが、検体の保存条件による変動が大きく、犬の血中ADAは他の動物に較べて非常に不安定であることが示唆された。腫瘍性疾患の血漿ADA活性値はリンパ腫、白血病、肝腫瘍、髄膜腫などの症例で治療開始前のADA活性に上昇が認められ、化学療法開始後は低下する傾向を示した。1年以上寛解が得られているリンパ腫、肺転移腫瘍、腹腔内腫瘍、肥満細胞腫などでは正常範囲内であり、ADAはリンパ系腫瘍の治療経過を観察する上で、病態の指標となりうることが示唆された。
    文部科学省, 基盤研究(C), 北海道大学, 連携研究者, 競争的資金, 09660335
  • 自己免疫疾患の分子機構
    1998年
    競争的資金
  • Molecular Mechanism of Autoimmune disease
    1998年
    競争的資金
  • 慢性腎疾患の進行に及ぼす摂取蛋白量の影響
    科学研究費助成事業 奨励研究(A)
    1995年 - 1995年
    滝口 満喜
    本研究の目的は、外科的に作出した慢性腎不全の猫に対する摂取蛋白量の影響を光学および電子顕微鏡を用いて組織学的に検索するとともに、慢性腎不全の進展因子として注目されている各種サイトカインや成長因子の関わりを検証することであった。
    慢性腎不全猫の作出に当たっては、右腎摘出に加え左腎動脈を部分結紮する腎亜全摘モデルの作出を試みたが、高度の手術手技を要することに加えて術後の状態が不安定であったことから、猫に与えるストレスが過大すぎると判断し、腎毒性を有する薬物(ピューロマイシン・アミノヌクレオシド)を投与することで腎障害の誘発を試みた。このピューロマイシン・アミノヌクレオシドはラットに特異的に腎障害を引き起こすことが知られているが、猫での報告はない。そのため、投与量および投与間隔を変えて実験を行う必要があった。その結果、ピューロマイシン・アミノヌクレオシドを猫に投与することによって蛋白尿をきたし、一部の糸球体に硬化病変が誘発されることが示唆された。また、電子顕微鏡によって糸球体上皮細胞足突起の癒合が観察された。血清生化学的にはBUNおよびクレアチニン値に上昇が認められた。尿中酵素ではNAGに変化が認められ、尿中サイトカインではIL-6が病変の進行に伴い増加する傾向が伺えた。
    以上のことからピューロマイシン・アミノヌクレオシドは猫に腎障害をもたらすことが示唆された。このモデルにおける病変の進展に及ぼす摂取蛋白量の影響については、現在、実験を継続中である。
    日本学術振興会, 奨励研究(A), 北海道大学, 07760292
  • 慢性腎疾患の進行に及ぼす摂取蛋白量の影響
    科学研究費補助金(奨励研究(A))
    1995年 - 1995年
    滝口 満喜
    本研究の目的は、外科的に作出した慢性腎不全の猫に対する摂取蛋白量の影響を光学および電子顕微鏡を用いて組織学的に検索するとともに、慢性腎不全の進展因子として注目されている各種サイトカインや成長因子の関わりを検証することであった。慢性腎不全猫の作出に当たっては、右腎摘出に加え左腎動脈を部分結紮する腎亜全摘モデルの作出を試みたが、高度の手術手技を要することに加えて術後の状態が不安定であったことから、猫に与えるストレスが過大すぎると判断し、腎毒性を有する薬物(ピューロマイシン・アミノヌクレオシド)を投与することで腎障害の誘発を試みた。このピューロマイシン・アミノヌクレオシドはラットに特異的に腎障害を引き起こすことが知られているが、猫での報告はない。そのため、投与量および投与間隔を変えて実験を行う必要があった。その結果、ピューロマイシン・アミノヌクレオシドを猫に投与することによって蛋白尿をきたし、一部の糸球体に硬化病変が誘発されることが示唆された。また、電子顕微鏡によって糸球体上皮細胞足突起の癒合が観察された。血清生化学的にはBUNおよびクレアチニン値に上昇が認められた。尿中酵素ではNAGに変化が認められ、尿中サイトカインではIL-6が病変の進行に伴い増加する傾向が伺えた。以上のことからピューロマイシン・アミノヌクレオシドは猫に腎障害をもたらすことが示唆された。このモデルにおける病変の進展に及ぼす摂取蛋白量の影響については、現在、実験を継続中である。
    文部科学省, 奨励研究(A), 北海道大学, 研究代表者, 競争的資金, 07760292
  • 超音波画像診断の応用の多様化と進展に関する研究
    科学研究費補助金(一般研究(B))
    1994年 - 1995年
    橋本 晃; 滝口 満善; 安田 準
    本研究課題の実施計画に基づいて行った2年間で得られた成績は以下に要約できる。1.超音波内視鏡(EUS)の臨床的応用:健康なビ-グル犬を用い、正常消化管および腹部各臓器の抽出方法およびEUS画像の集積を行った。EUSは特に消化管壁、胆嚢および膵臓の抽出に優れていた。セルレイン誘発性の実験的膵炎および人工的に胃壁に作出した血腫や嚢胞のEUSの成績から、膵臓疾患や消化管壁の局在性病変の診断にEUSの有用性が大きいことが明らかにされた。カラードプラ法の併用により、さらに診断精度および病変の質的変化の理解に役立つ情報が得られることが示唆された。以上の成績から、EUSは小動物臨床における有用性が高く、今後のさらなる進展が強く示唆された。2.超音波(US)ガイド下穿刺法の応用:犬のステロイド誘発性肝障害、猫の実験的脂肪肝やピューロマイシン投与による腎障害、さらには前立腺液採取のための二重バルーンカテーテル法の応用に関する研究で、それぞれの標的臓器の経時的な病理組織学的検索にUSガイド下穿刺法による生検を行った成績から、USガイド下穿刺法は小動物の種々臓器の生検に有用であり、応用性の進展が期待できると思われた。3.実験動物へのUSの応用:ウサギを用いたセファロリジン誘発性腎障害の腎病変のUS検査および猫条虫感染ラット肝臓の寄生虫性嚢胞の経時的変化のUS検査で得られた成績から、US検査は実験動物を用いる種々の研究において、新しい解析手技としての有用性、応用性が高いことが明らかにされた。4.小動物における腫瘍症例の画像診断への応用:犬および猫の各種腫瘍にUS診断を行い、多くの画像情報を集積した。またカラードプラ法の併用やUSガイド下穿刺法の併用によって腫瘍の確定診断や腫瘍の質的性状など診断精度の向上に資する成果も得られた。本研究によって得られた成果は、今後の獣医画像診断学の新たな展開に役立つ情報になるであろう。
    文部科学省, 一般研究(B), 北海道大学, 競争的資金, 06454127
  • 小動物の超音波診断
    1993年
    競争的資金
  • 小動物自然発生疾病の画像診断
    1993年
    競争的資金
  • Small Animal Dignostic Ultrasound
    1993年
    競争的資金
  • Small animal Diagnostic Imaging
    1993年
    競争的資金
  • 自己免疫の分子機構
    競争的資金
  • 自然発生動物疾病の画像診断
    競争的資金
  • Molecular pathogenesis of autoimmune diseases
    競争的資金
  • Diagnostic imaging of spontanous animal diseases
    競争的資金