研究者データベース

中村 健介(ナカムラ ケンスケ)
獣医学研究院 獣医学部門 臨床獣医科学分野
准教授

基本情報

所属

  • 獣医学研究院 獣医学部門 臨床獣医科学分野

職名

  • 准教授

学位

  • 博士(獣医学)(北海道大学大学院)

論文上での記載著者名

  • Kensuke Nakamura

科研費研究者番号

  • 80625898

J-Global ID

研究キーワード

  • 臨床獣医学   

研究分野

  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学
  • ライフサイエンス / 獣医学

職歴

  • 2017年04月 - 2020年06月 宮崎大学 テニュアトラック推進機構(獣医内科学分野) テニュアトラック准教授
  • 2011年09月 - 2017年03月 北海道大学大学院 附属動物病院 助教
  • 2011年01月 - 2011年08月 北海道大学大学院 博士研究員(日本学術振興会特別研究員PD)

所属学協会

  • 日本心エコー図学会   日本循環器学会   動物臨床医学会   日本獣医画像診断学会   日本獣医循環器学会   日本獣医師会   日本獣医学会   

研究活動情報

論文

  • Eiji Furukoji, Atsushi Yamashita, Kensuke Nakamura, Toshinori Hirai, Yujiro Asada
    Thrombosis research 183 76 - 79 2019年11月 [査読有り][通常論文]
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Kiwamu Hanazono, Keitaro Morishita, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 9 1259 - 1265 2019年09月03日 [査読有り][通常論文]
     
    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.
  • Masahiro Tamura, Kensuke Nakamura, Tatsuyuki Osuga, Genya Shimbo, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 8 1104 - 1108 2019年08月09日 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography (CEUS) is useful to distinguish benign and malignant focal liver lesions in dogs. Cholangiocellular adenoma is an extremely rare benign tumor in dogs and has not been examined using CEUS with Sonazoid. The aim of this study was to describe findings of CEUS with Sonazoid in three dogs with cholangiocellular adenoma. All three dogs showed contrast defects in the Kupffer phase and these findings mimicked malignant neoplasia during the Kupffer phase. Moreover, all dogs showed early washout and hypoechoic lesions relative to the surrounding normal liver parenchyma in the portal phase. To our knowledge, this is the first study to report that CEUS findings of cholangiocellular adenoma with Sonazoid mimicked malignancy in three dogs.
  • Khoirun Nisa, Hiroshi Ohta, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Yumiko Kagawa, Mitsuyoshi Takiguchi
    JAPANESE JOURNAL OF VETERINARY RESEARCH 67 3 221 - 227 2019年08月 [査読有り][通常論文]
     
    Ultra low fat diet (ULFD) has shown a good therapeutic effect in dogs with intestinal lymphangiectasia secondary to CE (IL-CE). As we hypothesized that the mechanism of ULFD may involve the resolution of immunological impairment in IL-CE dogs, our study aimed to investigate the effect of ULFD on the circulating regulatory T cell (Treg) of IL-CE dogs. Treg frequency of pre- and post-ULFD blood samples from dogs with IL-CE (n = 3) were measured using flow cytometry. Treg frequency in IL-CE group before ULFD treatment showed lower tendency when compared to healthy control (mean +/- SD; 2.0 +/- 1.6% and 4.3 +/- 1.4%, respectively), and showed increased tendency after ULFD (mean +/- SD; 4.5 +/- 3.5%). The results suggested that ULFD might restore circulating Treg frequency of IL-CE dogs.
  • Angkhana Dermlim, Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Khoirun Nisa, Kazuyoshi Sasaoka, Rommaneeya Leela-Arporn, Noriyuki Nagata, Masahiro Tamura, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 7 949 - 957 2019年07月11日 [査読有り][通常論文]
     
    The purpose of this study was to evaluate the cardiac acute volume loading effect on left atrial (LA) strain and strain rate (SR) parameters derived from two-dimensional speckle tracking echocardiography (2D-STE) in healthy dogs. Six healthy beagles were anesthetized and subjected to increase cardiac preload by intravenous infusion with lactated Ringer solution at 150 ml/kg/hr for 90 min. A Swan-Ganz catheter was placed to directly measure the mean pulmonary capillary wedge pressure (PCWP). Echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 min after acute volume loading began. Apical 4-chamber images focused on the LA were digitally recorded for later strain and SR analysis via 2D-STE. Acute volume loading significantly increased from baseline during LA strain and SR as assessed by the speckle tracking-based technique during reservoir and conduit function at 15 to 90 min after volume load began, and strain indices representing booster pump function were enhanced at 45 to 90 min. In addition, acute volume loading resulted in a significantly greater PCWP after fluid infusion. On multiple regression analysis, quadratic regression analysis was a better fit for the relationship between PCWP and all LA functional indices. Our findings indicated that LA function analyzed by strain and SR was enhanced during cardiac acute volume loading in healthy dogs. The change in strain and SR during acute volume loading should be interpreted with caution during the diagnosis of heart diseases related to volume overload.
  • Satoshi Takagi, Kensuke Nakamura, Ryo Takeuchi, Kiwamu Hanazono
    Journal of the American Veterinary Medical Association 255 1 51 - 53 2019年07月01日 [査読有り][通常論文]
  • A. Dermlim, K. Nakamura, T. Morita, T. Osuga, K. Nisa, K. Sasaoka, R. Leela-arporn, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Cardiology 23 69  Elsevier {BV} 2019年06月 [査読有り][通常論文]
  • T. Morita, K. Nakamura, T. Osuga, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Cardiology 23 1  Elsevier {BV} 2019年06月 [査読有り][通常論文]
  • Leela-Arporn R, Ohta H, Nagata N, Sasaoka K, Tamura M, Dermlim A, Nisa K, Morishita K, Sasaki N, Nakamura K, Takagi S, Hosoya K, Takiguchi M
    Veterinary journal (London, England : 1997) 248 74 - 78 2019年06月 [査読有り][通常論文]
  • Rommaneeya Leela-Arporn, Hiroshi Ohta, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Khoirun Nisa, Keitaro Morishita, Noboru Sasaki, Kensuke Nakamura, Satoshi Takagi, Kenji Hosoya, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 81 5 723 - 729 2019年05月31日 [査読有り][通常論文]
     
    A definitive diagnosis of focal liver lesions (FLLs) requires invasive procedures for histopathologic examination. Thus, a simpler noninvasive diagnostic method, such as conventional ultrasonography combined with clinical data, is needed for the prediction of liver malignancy. The objective of this study was to examine the diagnostic accuracy of clinical data and ultrasonographic (US) features to differentiate benign and malignant liver lesions. Medical records and US images from dogs with FLLs that underwent abdominal US and histopathologic examinations following surgery or liver biopsy were retrospectively reviewed. Clinical data, including signalment, clinical signs and laboratory findings, and the US features of liver lesions that could act as predictive factors were assessed using univariate and multivariate analyses to evaluate the associations between predictive factors and liver malignancy. Based on the histopathologic results, 55 dogs with malignant lesions and 28 dogs with benign lesions were included in the study. The results of univariate analysis showed that several US features and platelet count were significantly associated with liver malignancy. Multivariate analysis revealed that the platelet count (thrombocytosis; odds ratio [OR]: 4.13, 95% confidence intervals [CI]: 1.81-9.41), lesion size (4.1 cm or greater; OR: 23.83, 95% CI: 3.74-151.95) and echotexture of FLLs (heterogenous; OR: 8.44; 95% CI: 1.37-51.91) were independent predictors for differentiating benign and malignant liver lesions, suggesting that a combination of clinical data and US findings of FLLs could predict liver malignancy in dogs.
  • Yasutomo Hori, Yasuhiro Heishima, Yohei Yamashita, Masayuki Iguchi, Kensuke Nakamura, Noriko Isayama, Hideyuki Onodera, Akihito Kitade, Nobuyuki Kanno, Atsushi Hirakawa, Michio Katagi, Toshiki Ibaragi, Shigeki Yamano, Yoshitaka Aramaki, Tamotsu Sawada
    The Journal of veterinary medical science 81 4 513 - 516 2019年04月16日 [査読有り][通常論文]
     
    We investigated the clinical characteristics of healthy cats in accordance with the target organ damage (TOD) risk category, on the basis of systolic blood pressure (SBP). This prospective multi-center study included 137 healthy cats. Indirect blood pressure was measured using an oscillometric technique. The median SBP in all cats was 147 mmHg (interquartile range: 134-158). On the basis of the TOD risk category, 57.7, 19.7, 21.9, and 0.7% of the cats were classified into categories I-IV, respectively. Age, sex, and body weight did not affect the SBP. This study provides basic information on the distribution of TOD risk categories in clinically healthy cats.
  • 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][通常論文]
  • Khoirun Nisa, Sue Yee Lim, Masayoshi Shinohara, Tatsuyuki Osuga, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 33 2 559 - 568 2019年03月 [査読有り][通常論文]
     
    BACKGROUND: Contrast-enhanced ultrasonography (CEUS) can be used to evaluate intestinal perfusion in healthy dogs. It is helpful for diagnosing and monitoring inflammatory bowel disease in humans and could be useful for dogs with chronic intestinal diseases. OBJECTIVES: To examine duodenal perfusion in dogs with chronic inflammatory enteropathy (CIE) and intestinal lymphoma. ANIMALS: Client-owned dogs with CIE (n = 26) or intestinal lymphoma (n = 7) and dogs with gastrointestinal signs but histopathologically normal duodenum (controls, n = 14). METHODS: In this cross-sectional study, dogs with CIE were classified into remission (n = 16) and symptomatic (n = 10) groups based on clinical scores determined at the time of CEUS. The duodenum was scanned after IV injection of Sonazoid® (0.01 mL/kg). CEUS-derived perfusion parameters, including time-to-peak, peak intensity (PI), area under the curve (AUC), and wash-in and wash-out rates were evaluated. RESULTS: The PI was significantly higher in the symptomatic CIE group (median (range); 105.4 (89.3-128.8) MPV) than in the control group (89.9 (68.5-112.2) MPV). The AUC was significantly higher in the symptomatic CIE group (4847.9 (3824.3-8462.8) MPV.sec) than in the control (3448.9 (1559.5-4736.9) MPV.sec) and remission CIE (3862.3 (2094.5-6899.0) MPV.sec) groups. The PI and clinical score were positively correlated in the CIE group. No significant differences in perfusion parameters were detected between the lymphoma and CIE groups or the lymphoma and control groups. CONCLUSIONS AND CLINICAL IMPORTANCE: The PI and AUC can detect duodenal inflammation and hence are potentially useful for excluding a diagnosis of CIE.
  • Osamu Ichii, Hiroshi Ohta, Taro Horino, Teppei Nakamura, Marina Hosotani, Tatsuya Mizoguchi, Keitaro Morishita, Kensuke Nakamura, Noboru Sasaki, Mitsuyoshi Takiguchi, Ryo Sato, Kazuhisa Oyamada, Yaser Hosny Ali Elewa, Yasuhiro Kon
    Frontiers in veterinary science 6 2 - 2 2019年 [査読有り][通常論文]
     
    [This corrects the article DOI: 10.3389/fvets.2018.00289.].
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Nozomu Yokoyama, Keitaro Morishita, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    American journal of veterinary research 80 1 51 - 60 2019年01月 [査読有り][通常論文]
     
    OBJECTIVE To determine the relationship between acute volume overload and echocardiographic indices of right ventricular (RV) function and dyssynchrony in healthy dogs. ANIMALS 7 healthy Beagles. PROCEDURES Right heart catheterization and echocardiography were performed in 7 healthy anesthetized Beagles at baseline and after induction of volume overload. Volume overload was induced by IV infusion of lactated Ringer solution (150 mL/kg/h for 90 minutes). Echocardiographic indices of RV function, including peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, RV Tei index, RV longitudinal strain (RVLS), and systolic RV longitudinal strain rate (RVLSR), were obtained by use of speckle tracking echocardiography (STE). In addition, SD of the systolic shortening time of the right ventricle for the 6 segments (RV-SD6) was determined with STE. RESULTS Volume overload significantly increased the RV end-diastolic pressure, compared with the baseline value. Echocardiographic indices of RV function, except for septal RVLSR, were significantly enhanced by volume overload. In contrast, RV-SD6 did not change with volume overload. Although echocardiographic indices of RV function, except for septal RVLSR, were correlated with RV end-diastolic pressure, RV-SD6 was not correlated. CONCLUSIONS AND CLINICAL RELEVANCE Echocardiographic indices of RV function, including RVLS and RVLSR, were affected by acute short-term volume overload. Therefore, results for assessment of RV function by use of STE in dogs with clinical conditions associated with right-sided chronic volume overload, such as tricuspid and pulmonic regurgitation, should be interpreted with caution.
  • Hiroshi Ohta, Kazuki Kojima, Nozomu Yokoyama, Noboru Sasaki, Yumiko Kagawa, Kiwamu Hanazono, Tomohito Ishizuka, Keitaro Morishita, Kensuke Nakamura, Satoshi Takagi, Mitsuyoshi Takiguchi
    Canadian journal of veterinary research = Revue canadienne de recherche veterinaire 82 4 278 - 286 2018年10月 [査読有り][通常論文]
     
    The objective of this study was to examine the effects of immunosuppressive prednisolone therapy on pancreatic tissue and the concentration of serum canine pancreatic lipase immunoreactivity (cPLI) in healthy dogs. Six healthy beagle dogs were subcutaneously administered an immunosuppressive dose of prednisolone [4 mg/kg body weight (BW)] once daily for either 2 or 3 weeks. Serum cPLI concentration was measured before and after treatment. Ultrasonographic examination of the pancreas and laparoscopic biopsy and histopathological examination of the right pancreatic lobe and the liver were also conducted before and after treatment. The expression of pancreatic lipase messenger ribonucleic acid (mRNA) in the pancreas and liver was examined by polymerase chain reaction (PCR). Although the serum cPLI concentration was significantly higher on day 14 and on the day of the second laparoscopy than before treatment, it was classified as normal (≤ 200 μg/L) in 5 dogs and as abnormal (≥ 400 μg/L) in only 1 dog. None of the 6 dogs showed clinical signs of pancreatitis during the study period. After treatment, ultrasonographic examination of the pancreas showed no changes except for a hypoechoic pancreas in 1 dog. Histopathological examination of the right pancreatic lobe in all dogs showed no evidence of pancreatitis after treatment. Pancreatic lipase mRNA expression was detected in the pancreas, but not in the liver, before and after treatment. The administration of 4 mg/kg BW per day of prednisolone for 2 or 3 weeks increased the serum cPLI concentration without clinical signs of pancreatitis, although an abnormal cPLI concentration (≥ 400 μg/L) was observed in only 1 dog. No ultrasonographic or histological evidence of pancreatitis was observed in any of the dogs.
  • Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Kiyomasa Watanabe, Mitsuyoshi Takiguchi
    Journal of the American Veterinary Medical Association 253 4 417 - 420 2018年08月15日 [査読有り][通常論文]
  • Yasutomo Hori, Kensuke Nakamura, Nobuyuki Kanno, Makoto Hitomi, Yohei Yamashita, Satoshi Hosaka, Noriko Isayama, Takahiro Mimura
    The Journal of veterinary medical science 80 8 1212 - 1218 2018年08月10日 [査読有り][通常論文]
     
    Alacepril is a relatively novel angiotensin-converting enzyme inhibitor; however, the safety, tolerance, and efficacy of alacepril in terms of cough suppression in dogs with mitral valve disease (MVD) remain unknown. The aim of this study was to investigate the safety, tolerance, and cough suppression efficacy of alacepril in dogs with MVD. This was a multi-center, prospective study. Forty-two dogs with echocardiographic or radiographic evidence of cardiac enlargement in addition to cough were enrolled. Dogs were treated with alacepril (1.0-3.0 mg/kg/day) for at least 4 weeks. One dog (2.4%) developed complications, including appetite loss, lethargy, and vomiting. Thirty-six dogs were re-evaluated after 4 weeks of treatment. Cough resolved or improved in 20 dogs (55.6%) after treatment. Based on the efficacy of alacepril, the dogs were divided into an effective group (n=20) and an ineffective group (n=16). After treatment, the left ventricular end-diastolic internal diameter corrected for body weight was significantly increased from baseline in the ineffective group but was significantly decreased in the effective group. Univariate binomial logistic regression analyses showed that high atrial natriuretic peptide level, N-terminal pro-B-type natriuretic peptide level, and E wave velocity at baseline were significantly correlated with alacepril inefficacy. Alacepril as treatment for MVD is well tolerated in most dogs, and different conditions of cardiac loading may influence the effect of the drug. Alacepril is expected to improve the quality of life of dogs with early stage MVD.
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Atsushi Kobayashi, Osamu Ichii, Akira Yabuki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 80 6 939 - 944 2018年06月29日 [査読有り][通常論文]
     
    A 12 year-old intact male Pembroke Welsh corgi weighing 10.8 kg was presented for evaluation of a 3-month history of dyspnea, and a 1-week history of exercise intolerance and anorexia. Severe hypoxemia (PaO2 56 mmHg), diffuse lung alveolar infiltration, and severe pulmonary hypertension (PH) (tricuspid regurgitation pressure gradient was 81 mmHg) were identified. A tentative diagnosis of severe PH due to lung disease or pulmonary thromboembolism was made and treated intensively. After 5 days of hospitalization, the dog died despite oxygen supplementation and anticoagulant therapy. This dog was diagnosed as unclassified interstitial lung disease based on histopathological findings.
  • Yasutomo Hori, Masayuki Iguchi, Yasuhiro Heishima, Yohei Yamashita, Kensuke Nakamura, Atsushi Hirakawa, Akihito Kitade, Toshiki Ibaragi, Michio Katagi, Tamotsu Sawada, Masashi Yuki, Nobuyuki Kanno, Haruki Inaba, Noriko Isayama, Hideyuki Onodera, Naoki Iwasa, Mikio Kino, Mikihiro Narukawa, Syuhei Uchida
    Journal of veterinary internal medicine 32 3 922 - 929 2018年05月 [査読有り][通常論文]
     
    BACKGROUND: Cardiac troponin I (cTnI) is useful for assessing hypertrophic cardiomyopathy (HCM) in cats. OBJECTIVE: To measure plasma cTnI concentrations in healthy cats and evaluate the clinical utility of cTnI in determining the severity of HCM. ANIMALS: Clinically healthy cats (n = 88) and cats with HCM (n = 93). METHODS: Multicenter prospective study. Cats with HCM, including hypertrophic obstructive cardiomyopathy at various stages, were diagnosed using echocardiography. Plasma cTnI concentrations were analyzed by a commercial laboratory. Receiver-operating characteristic curve analysis was used to evaluate the accuracy of plasma cTnI concentrations to detect HCM. RESULTS: The median cTnI concentration was 0.027 ng/mL (interquartile range, 0.012-0.048 ng/mL) in healthy cats. Concentrations were significantly higher in diseased cats than in healthy controls, and concentrations were significantly higher in cats with heart failure than in asymptomatic cats. A plasma cTnI concentration of 0.163 ng/mL had a sensitivity of 62.0% and specificity of 100% when used to distinguish normal cats from asymptomatic HCM cats without left atrial dilatation. A cutoff of 0.234 ng/mL had high sensitivity (95.0%) and specificity (77.8%) for assessing heart failure. The areas under the receiver-operating characteristic curves were 0.85 and 0.93, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Increased cTnI concentrations reflect the severity of HCM. If other causes of cardiac injury are ruled out, plasma cTnI concentration may be useful for predicting the severity of HCM in cats.
  • Khoirun Nisa, Sue Yee Lim, Tatsuyuki Osuga, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 80 3 453 - 459 2018年03月24日 [査読有り][通常論文]
     
    Quantitative contrast-enhanced ultrasonography (CEUS) enables non-invasive and objective evaluation of intestinal perfusion by quantifying the intensity of enhancement on the intestine after microbubble contrast administration. During CEUS scanning, sedation is sometimes necessary to maintain animal cooperation. Nevertheless, the effect of sedative administration on the canine intestinal CEUS is unknown. This study aimed to investigate the effect of sedation with a combination of butorphanol and midazolam on the duodenal CEUS-derived perfusion parameters of healthy dogs. For this purpose, duodenum was imaged following contrast administration (Sonazoid®, 0.01 ml/kg) in six healthy beagles before and after intravenous injection of a combination of butorphanol (0.2 mg/kg) and midazolam (0.1 mg/kg). Furthermore, hemodynamic parameters including blood pressure and heart rate were recorded during the procedure. Five CEUS derived perfusion parameters including time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), wash-in and wash-out rates (WiR and WoR, respectively) before and after sedation were statistically compared. The result showed that no significant change was detected in any of perfusion parameters. Systolic and mean arterial pressures significantly reduced after sedative administration, but diastolic arterial pressure and heart rate did not significantly change. Moreover, no significant partial correlation was observed between perfusion parameters and hemodynamic parameters. Thus, we concluded that the combination did not cause significant influence in duodenal CEUS perfusion parameters and could be a good option for sedation prior to duodenal CEUS in debilitated dogs.
  • Yasutomo Hori, Yasuhiro Heishima, Yohei Yamashita, Noriko Isayama, Nobuyuki Kanno, Kensuke Nakamura, Masayuki Iguchi, Toshiki Ibaragi, Hideyuki Onodera, Yoshitaka Aramaki, Atsushi Hirakawa, Shigeki Yamano, Michio Katagi, Akihito Kitade, Tamotsu Sawada
    The Journal of veterinary medical science 80 3 447 - 452 2018年03月24日 [査読有り][通常論文]
     
    Chronic kidney disease (CKD) is a common cause of secondary systemic hypertension in cats. We investigated the relationship between indirect blood pressure and the prevalence of systemic hypertension in various CKD stages in cats. Client-owned cats (24 control cats and 77 cats with CKD) were included. Biochemical examinations of plasma were conducted by a commercial laboratory. Diseased cats were divided into two groups based on the International Renal Interest Society (IRIS) guidelines (II and III-IV). Indirect blood pressure was measured using an oscillometric technique. Severe hypertension was diagnosed if systolic blood pressure (SBP) was ≥180 mmHg. Indirect blood pressures were significantly higher in IRIS stage III-IV than in the control cats. Of 77 cats with CKD, 25 (32.5%) had severe hypertension. The frequency of severe hypertension increased with an increase in IRIS stage; 0% in the controls, 27.6% in the IRIS stage II, and 47.4% in the IRIS stage III-IV, respectively. The indirect SBP was weakly correlated with urea nitrogen (r=0.27) and creatinine (r=0.23) concentrations in plasma. Binary logistic regression analysis showed that if plasma creatinine concentration is >3.7 mg/dl, cats with CKD had an increased risk for developing severe hypertension (P<0.001). Our results suggest that indirect blood pressure was correlated with the severity of CKD, and the prevalence of severe hypertension increased in cats with severe CKD. The risk of severe hypertension may be high in cats with severe CKD.
  • 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][通常論文]
  • Y. Heishima, Y. Hori, K. Nakamura, Y. Yamashita, N. Isayama, N. Kanno, M. Katagi, H. Onodera, S. Yamano, Y. Aramaki
    Journal of Veterinary Cardiology 20 4 234 - 243 2018年 [査読有り][通常論文]
     
    Objectives: Plasma atrial natriuretic peptide (ANP) levels have been reported to be elevated in cats with cardiomyopathy. We investigated the diagnostic accuracy of plasma ANP concentration as an indicator of the severity of cardiomyopathies. Animals: This study included 78 control cats and 83 cats with various types of cardiomyopathy. Methods: This was a prospective multicentre study. Control cats were determined to have a normal heart, and diseased cats were diagnosed by echocardiography. Diseased cats were divided into asymptomatic cats without left atrial dilation (LAD), asymptomatic cats with LAD, and cats with heart failure. Plasma C-terminal ANP concentrations were measured using chemiluminescence. Results: The median plasma ANP concentration in controls was 43.3 (interquartile range, 33.0–56.3) pg/mL. Plasma ANP values were significantly higher in the cardiomyopathic cats with LAD and heart failure, but the values in cats without LAD were comparable to those in control cats. To distinguish cats with cardiomyopathy from controls, a plasma ANP concentration > 77.5 pg/mL afforded sensitivity of 66.3% and specificity of 84.6%. Use of plasma ANP concentration > 110.9 pg/mL to identify cats with LAD had a sensitivity of 73.6% and specificity of 93.5%. The areas under the receiver-operating characteristic curve were 0.80 and 0.86. Conclusions: Plasma ANP concentrations were higher in cats with more advanced cardiomyopathy. Although assaying the ANP concentration alone may not help to diagnose cardiac disease, measuring provides additional information that is useful for assessing the severity of cardiomyopathies.
  • K. Sasaoka, K. Nakamura, T. Osuga, T. Morita, N. Yokoyama, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 32 1 314 - 323 2018年01月01日 [査読有り][通常論文]
     
    Background: Transcranial Doppler ultrasound examination (TCD) is a rapid, noninvasive technique used to evaluate cerebral blood flow and is useful for the detection of intracranial hypertension in humans. However, the clinical usefulness of TCD in diagnosing intracranial hypertension has not been demonstrated for intracranial diseases in dogs. Objectives: To determine the association between the TCD variables and intracranial hypertension in dogs with intracranial diseases. Animals: Fifty client-owned dogs with neurologic signs. Methods: Cross-sectional study. All dogs underwent TCD of the basilar artery under isoflurane anesthesia after magnetic resonance imaging (MRI). Dogs were classified into 3 groups based on MRI findings: no structural diseases (group I), structural disease without MRI evidence of intracranial hypertension (group II), and structural disease with MRI evidence of intracranial hypertension (group III). The TCD vascular resistance variables (resistive index [RI], pulsatility index [PI], and the ratio of systolic to diastolic mean velocity [Sm/Dm]) were measured. Results: Fifteen, 22, and 13 dogs were classified into groups I, II, and III, respectively. Dogs in group III had significantly higher Sm/Dm (median, 1.78 range, 1.44–2.58) than those in group I (median, 1.63 range, 1.43–1.75) and group II (median, 1.62 range, 1.27–2.10). No significant differences in RI and PI were identified among groups. Conclusions and Clinical Importance: Our findings suggest that increased Sm/Dm is associated with MRI findings of suspected intracranial hypertension in dogs with intracranial diseases and that TCD could be a useful tool to help to diagnose intracranial hypertension.
  • Osamu Ichii, Hiroshi Ohta, Taro Horino, Teppei Nakamura, Marina Hosotani, Tatsuya Mizoguchi, Keitaro Morishita, Kensuke Nakamura, Noboru Sasaki, Mitsuyoshi Takiguchi, Ryo Sato, Kazuhisa Oyamada, Yaser Hosny Ali Elewa, Yasuhiro Kon
    Frontiers in veterinary science 5 289 - 289 2018年 [査読有り][通常論文]
     
    Increased incidence of kidney disease (KD) is a common concern in human and companion animals. Cats, in particular, are highly susceptible to KD. Novel KD biomarkers would help to address these problems. Therefore, we are focusing on microRNA, a highly conserved nucleic acid, as a KD biomarker for various animals. We previously reported that altered levels of urinary exosome (UExo)-derived microRNAs indicate renal pathologies in dogs. This study comprehensively examined UExo-derived microRNAs, which reflected the KD status in cats. The examined cats were divided into two groups: normal renal function (NR) and KD. Based on our previous data in dogs and cats, as well as the present data on UExo-derived microRNAs in cats by next-generation sequencing, let-7b, let-7f, miR-10a, miR-10b, miR-21a, miR-22, miR-26a, miR-27b, miR-146a, miR-181a, miR-191, and miR-486a were identified as biomarker candidates. In summary, the levels of UExo-derived let-7b, miR-22, and miR-26a significantly decreased in cats with KD from the early stages of the disease. UExo-derived miRNA levels normalized to urinary creatinine or total RNA of miR-21a was significantly higher in the KD group. Importantly, the ratio of UExo-derived miR-21a to let-7b showed a significant and strongest correlation with serum creatinine (ρ = 0.751), blood urea nitrogen (ρ = 0.754), and urinary creatinine (ρ = -0.421) among all examined indices. Further, the ratio of miR-181a to let-7b or miR-10b significantly correlated with the progression of renal dysfunction in the KD group. Thus, we identified that UExo-derived microRNAs in cats, and their raw and normalized levels could indicate altered renal function.
  • Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Yumiko Kagawa, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Canadian veterinary journal = La revue veterinaire canadienne 58 11 1167 - 1170 2017年11月 [査読有り][通常論文]
     
    A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls.
  • Khoirun Nisa, Sue Yee Lim, Masayoshi Shinohara, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Nozomu Yokoyama, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 79 9 1585 - 1590 2017年09月29日 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography (CEUS) with microbubbles as a contrast agent allows the visualization and quantification of tissue perfusion. The assessment of canine intestinal perfusion by quantitative CEUS may provide valuable information for diagnosing and monitoring chronic intestinal disorders. This study aimed to assess the repeatability (intraday variability) and reproducibility (interday variability) of quantitative duodenal CEUS in healthy dogs. Six healthy beagles underwent CEUS three times within one day (4-hr intervals) and on two different days (1-week interval). All dogs were sedated with a combination of butorphanol (0.2 mg/kg) and midazolam (0.1 mg/kg) prior to CEUS. The contrast agent (Sonazoid®) was administered using the intravenous bolus method (0.01 ml/kg) for imaging of the duodenum. Time-intensity curves (TIC) were created by drawing multiple regions of interest (ROIs) in the duodenal mucosa, and perfusion parameters, including the time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), and wash-in and wash-out rates (WiR and WoR, respectively), were generated. Intraday and interday coefficients of variation (CVs) for TTP, PI, AUC, WiR and WoR were <25% (range, 2.27-23.41%), which indicated that CEUS was feasible for assessing duodenal perfusion in healthy sedated dogs. A further study of CEUS in dogs with chronic intestinal disorders is necessary to evaluate its clinical applicability.
  • 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][通常論文]
  • T. Morita, K. Nakamura, T. Osuga, N. Yokoyama, N. Khoirun, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY CARDIOLOGY 19 4 351 - 362 2017年08月 [査読有り][通常論文]
     
    Introduction: To assess the repeatability and characteristics of echocarCanine; diographic indices of the right ventricular (RV) function derived from speckle-track Cardiac; ing echocardiography. Right ventricular Animals: Fourteen laboratory Beagles and 103 privately owned dogs without cardifunction; ac disease were involved in this study. Dyssynchrony; Materials and methods: Right ventricular longitudinal strain, strain rate, and a Tei index strain-related index for assessing RV dyssynchrony derived from speckle-tracking echocardiography were obtained by two different observers using five Beagles. Within-day, between-day, and interobserver coefficients of variation and the intraclass correlation coefficient of speckle-tracking echocardiography indices were determined. Both speckle-tracking echocardiography and conventional indices of RV function, including the peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, and the Tel index, were obtained from 14 Beagles and 103 privately owned dogs. Relationships between echocardiographic indices and the body weight, heart rate, age, and sex were estimated by regression analysis. Results: Speckle-tracking echocardiographic indices showed good within-day repeatability, between-day and interobserver repeatability were moderate to good. In large dogs, RV longitudinal strain, strain rate, and fractional area change were significantly decreased, while the index of RV dyssynchrony, systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, and the Tei index were increased. All speckle-tracking and conventional echocardiographic indices were correlated with the body weight. Discussion and conclusions: The speckle-tracking echocardiography indices were highly repeatable and body weight affected speckle-tracking echocardiography indices in dogs. Further studies are needed to apply speckle-tracking echocardiography indices in dogs with cardiac disease. (C) 2017 Elsevier B.V. All rights reserved.
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Nozomu Yokoyama, Keitaro Morishita, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    Echocardiography (Mount Kisco, N.Y.) 34 7 1040 - 1049 2017年07月 [査読有り][通常論文]
     
    BACKGROUND: The assessment of hemodynamic change by echocardiography is clinically useful in patients with pulmonary hypertension. Recently, mild elevation of the mean pulmonary arterial pressure (PAP) has been shown to be associated with increased mortality. However, changes in the echocardiographic indices of right ventricular (RV) function are still unknown. The objective of this study was to validate the relationship between echocardiographic indices of RV function and right heart catheterization variables under a mild RV pressure overload condition. METHODS AND RESULTS: Echocardiography and right heart catheterization were performed in dog models of mild RV pressure overload induced by thromboxane A2 analog (U46619) (n=7). The mean PAP was mildly increased (19.3±1.1 mm Hg), and the cardiac index was decreased. Most echocardiographic indices of RV function were significantly impaired even under a mild RV pressure overload condition. Multivariate analysis revealed that the RV free wall longitudinal strain (RVLS), standard deviation of the time-to-peak longitudinal strain of RV six segments (RV-SD) by speckle-tracking echocardiography, and Tei index were independent echocardiographic predictors of the mean PAP (free wall RVLS, β=-0.60, P<.001; RV-SD, β=0.40, P=.011), pulmonary vascular resistance (free wall RVLS, β=-0.39, P=.020; RV-SD, β=0.47, P=.0086; Tei index, β=0.34, P=.047), and cardiac index (Tei index, β=-0.65, P<.001). CONCLUSIONS: Free wall RVLS, RV-SD, and Tei index are useful for assessing the hemodynamic change under a mild RV pressure overload condition.
  • Nozomu Yokoyama, Hiroshi Ohta, Yumiko Kagawa, Noriyuki Nagata, Khoirun Nisa, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Mitsuyoshi Takiguchi
    Veterinary immunology and immunopathology 188 78 - 83 2017年06月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are a possible novel form of breed-specific canine inflammatory bowel disease (IBD). In this pilot study, we investigated the effects of different Toll like receptor (TLR2, TLR4, TLR5 and TLR9) ligands on pro-inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α) gene expression in ex vivo-cultured colorectal samples from four MDs with ICRPs and four healthy MDs. At baseline, no significant difference in the mRNA expression levels of TLRs and pro-inflammatory cytokines was observed between cases and control MDs. After 4-h incubation, the relative ratios of TNF-α mRNA expression in the TLR2- or TLR4-stimulated colorectal samples, and IL-1β mRNA expression in the TLR9-stimulated colorectal samples form cases showed higher tendency compared with healthy MDs (P<0.05), although statistically not significant. The results of this pilot study using small number of cases indicated that reactivity against TLR2, TLR4 or TLR9 ligand in the production of pro-inflammatory cytokines might be enhanced in the colorectal mucosa of ICRPs. Further research is needed to perform the functional analysis of TLRs in the sole cell population using intestinal epithelial primary culture and the mononuclear cells isolated from colonic mucosa.
  • H. Ohta, T. Morita, N. Yokoyama, T. Osuga, N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi
    JOURNAL OF SMALL ANIMAL PRACTICE 58 6 342 - 347 2017年06月 [査読有り][通常論文]
     
    ObjectivesIn this pilot study, serum canine pancreatic lipase immunoreactivity was measured repeatedly in dogs with various immune-mediated diseases that were treated with immunosuppressive doses of prednisolone. MethodsTen client-owned dogs with newly diagnosed immune-mediated disease that had normal canine pancreatic lipase immunoreactivity concentrations (200 mu g/l) were treated with 2 to 2.2 mg/kg prednisolone orally once daily as the initial treatment. Serum samples were obtained from each of the dogs prior to treatment and at 1- to 4-week intervals during immunosuppressive treatment. The highest canine pancreatic lipase immunoreactivity concentration detected during immunosuppressive treatment was defined as the peak canine pancreatic lipase immunoreactivity. ResultsPeak canine pancreatic lipase immunoreactivity concentrations were classified as normal in two dogs, questionable (201 to 399 mu g/l) in three dogs, and abnormal (400 mu g/l) in five dogs. Peak canine pancreatic lipase immunoreactivity concentrations were significantly higher than baseline canine pancreatic lipase immunoreactivity concentrations but there was no evidence of clinical pancreatitis. Clinical SignificanceIt remains unclear whether the five of 10 dogs with elevated canine pancreatic lipase immunoreactivity during prednisone treatment had subclinical pancreatitis or whether the abnormal results were a consequence of prednisolone administration.
  • 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][通常論文]
     
    Background: Perflubutane microbubbles, a second-generation ultrasound contrast agent, are phagocytized by Kupffer cells. This characteristic may be useful to differentiate diffuse hepatic diseases in dogs. Hypothesis/objectives: To determine whether the washout ratio in the hepatic vein (HV) measured by contrast-enhanced ultrasonography (CEUS) can distinguish between inflammatory and noninflammatory hepatic disorders in dogs. Animals: Forty-one client-owned dogs with hepatic disorders including 14 with hepatitis, 7 with primary hypoplasia of the portal vein (PHPV), 9 with congenital portosystemic shunt (cPSS), and 11 with other hepatopathy were enrolled. Six dogs without hepatic disease also were evaluated as healthy controls. Methods: Dogs with hepatic disorders were prospectively included. Contrast-enhanced ultrasonography of the HV was performed for 2 minutes. Washout ratio was defined as the attenuation rate from peak intensity to the intensity at the end of the CEUS study. Results: Washout ratio in the hepatitis group (median, 18.0%; range, 2.0-37.0%) was significantly lower than that of the PHPV (median, 52.2%; range, 11.5-86.3%), cPSS (median, 60.0%; range, 28.6-77.4%), other hepatopathy (median, 70.5%; range, 26.6-88.4%), and normal (median, 78.0%; range, 60.7-91.7%) groups. The area under the receiver operating characteristic curve for hepatitis was 0.960, with a 95% confidence interval (CI) of 0.853-0.990. Washout ratio <= 37.1% resulted in a sensitivity of 100% (95% CI, 78.5-100%) and specificity of 85.2% (95% CI, 67.5-94.1%) for the prediction of hepatitis. Conclusions and Clinical Importance: Washout ratio can distinguish hepatitis from the other noninflammatory disorders with high accuracy. This result might reflect impaired Kupffer cell phagocytosis in dogs with hepatitis.
  • K. Morishita, A. Hiramoto, A. Michishita, S. Takagi, T. Osuga, S. Y. Lim, K. Nakamura, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 31 3 770 - 777 2017年05月01日 [査読有り][通常論文]
     
    Background: Perflubutane microbubbles, a second-generation ultrasound contrast agent, are phagocytized by Kupffer cells. This characteristic may be useful to differentiate diffuse hepatic diseases in dogs. Hypothesis/objectives: To determine whether the washout ratio in the hepatic vein (HV) measured by contrast-enhanced ultrasonography (CEUS) can distinguish between inflammatory and noninflammatory hepatic disorders in dogs. Animals: Forty-one client-owned dogs with hepatic disorders including 14 with hepatitis, 7 with primary hypoplasia of the portal vein (PHPV), 9 with congenital portosystemic shunt (cPSS), and 11 with other hepatopathy were enrolled. Six dogs without hepatic disease also were evaluated as healthy controls. Methods: Dogs with hepatic disorders were prospectively included. Contrast-enhanced ultrasonography of the HV was performed for 2 minutes. Washout ratio was defined as the attenuation rate from peak intensity to the intensity at the end of the CEUS study. Results: Washout ratio in the hepatitis group (median, 18.0% range, 2.0–37.0%) was significantly lower than that of the PHPV (median, 52.2% range, 11.5–86.3%), cPSS (median, 60.0% range, 28.6–77.4%), other hepatopathy (median, 70.5% range, 26.6–88.4%), and normal (median, 78.0% range, 60.7–91.7%) groups. The area under the receiver operating characteristic curve for hepatitis was 0.960, with a 95% confidence interval (CI) of 0.853–0.990. Washout ratio ≤37.1% resulted in a sensitivity of 100% (95% CI, 78.5–100%) and specificity of 85.2% (95% CI, 67.5–94.1%) for the prediction of hepatitis. Conclusions and Clinical Importance: Washout ratio can distinguish hepatitis from the other noninflammatory disorders with high accuracy. This result might reflect impaired Kupffer cell phagocytosis in dogs with hepatitis.
  • Y. Fujita, K. Hanazono, E. Uchida, T. Kawahata, A. Suto, K. Nakamura, H. Shimizu
    JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY AND VENEREOLOGY 31 4 E184 - E185 2017年04月 [査読有り][通常論文]
  • 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][通常論文]
     
    OBJECTIVE To assess the use of contrast-enhanced ultrasonography (CEUS) of the hepatic vein for the detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs. ANIMALS 6 healthy Beagles. PROCEDURES A prospective study was conducted. A catheter was surgically placed in the portal vein of each dog. Hypertension was induced by intraportal injection of microspheres (10 to 15 mg/kg) at 5-day intervals via the catheter. Microsphere injections were continued until multiple acquired portosystemic shunts were created. Portal vein pressure (PVP) was measured through the catheter. Contrast-enhanced ultrasonography was performed before and after establishment of hypertension. Time-intensity curves were generated from the region of interest in the hepatic vein. Perfusion variables measured for statistical analysis were hepatic vein arrival time, time to peak, time to peak phase (TTPP), and washout ratio. The correlation between CEUS variables and PVP was assessed by use of simple regression analysis. RESULTS Time to peak and TTPP were significantly less after induction of portal hypertension. Simple regression analysis revealed a significant negative correlation between TTPP and PVP. CONCLUSIONS AND CLINICAL RELEVANCE CEUS was useful for detecting hemodynamic changes associated with experimentally induced portal hypertension in dogs, which was characterized by a rapid increase in the intensity of the hepatic vein. Furthermore, TTPP, a time-dependent variable, provided useful complementary information for predicting portal hypertension. IMPACT FOR HUMAN MEDICINE Because the method described here induced presinusoidal portal hypertension, these results can be applied to idiopathic portal hypertension in humans.
  • Nozomu Yokoyama, Hiroshi Ohta, Yumiko Kagawa, Rommaneeya Leela-Arporn, Angkhana Dermlim, Khoirun Nisa, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 79 3 456 - 463 2017年03月18日 [査読有り][通常論文]
     
    We examine the expression of tight junction and adherence junction proteins in the colorectal mucosa of miniature dachshunds (MDs) with inflammatory colorectal polyps (ICRPs). Colorectal mucosa samples were endoscopically obtained from 8 MDs with ICRPs and 8 control dogs for immunoblotting. Paraffin-embedded tissues of surgically resected inflamed lesions from another 5 MDs with ICRPs and full-thickness colorectal specimens from 5 healthy beagles were obtained for immunohistochemistry. The expression patterns of claudin-1, -2, -3, -4, -5, -7 and -8, E-cadherin and β-catenin were analyzed in the non-inflamed mucosa and inflamed mucosa of ICRPs and colorectal mucosa of control dogs by immunoblotting. The localization of these proteins in the inflamed lesions was analyzed by immunohistochemistry. The expressions of each of claudin, E-cadherin and β-catenin were not significantly different between control dogs and non-inflamed colonic mucosa from MDs with ICRPs. In contrast, only E-cadherin and β-catenin were detected in the inflamed lesions of MDs with ICRPs. By immunohistochemistry, claudin-2, -3, -4, -5 and -7, E-cadherin and β-catenin were expressed in the colorectal epithelium within the inflamed mucosa, but not in granulation tissue. Distributions of claudin-2, -3, -4, -5, and -7, E-cadherin and β-catenin in the colonic epithelium were not different between MDs with ICRPs and control dogs. These results indicated that no significant alteration was detected in several tight junction or adherence junction proteins expression in the colorectal epithelium of ICRPs.
  • K. Nakamura, S. Kawamoto, T. Osuga, T. Morita, N. Sasaki, K. Morishita, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 31 2 316 - 325 2017年03月 [査読有り][通常論文]
     
    Background: Decreased function of the left atrium (LA) is a useful prognostic indicator in dogs with myxomatous mitral valve disease (MMVD). In humans, LA strain is a novel severity indicator of mitral regurgitation, but its clinical utility in dogs has not been confirmed. Objectives: To examine whether LA strain as evaluated with speckle-tracking echocardiography is associated with MMVD stage in dogs. Animals: Fifty-two client-owned dogs with MMVD. Methods: Cross-sectional study. Dogs were classified as stage B1, B2, C, or D, according to the American College of Veterinary Internal Medicine consensus. Physical examination findings and echocardiographic variables were compared among the groups. To assess the comparative accuracy of echocardiographic variables in identifying dogs with the presence or history congestive heart failure (CHF), receiver operating characteristic curves and multivariate logistic analysis were used. Results: There were no significant differences in parameters of LA strain between B1 and B2 groups. However, LA longitudinal strain during atrial contraction (epsilon(A)) (median, 19.1%; interquartile range, 15.3-24.3% in B1, 19.6%; 14.1-21.4% in B2, 6.2%; 3.18-11.2% in C/D) and during ventricular systole (eS) (32.7%; 28.9-39.2% in B1, 35.6%; 31.7-41.9% in B2, 23.6%; 16.9-26.1% in C/D) were significantly lower in stages C/D than in stages B1 and B2. In multivariate logistic regression analysis, eA and peak early diastolic mitral inflow velocity were identified as independent indicators of stage C/D. Conclusions and Clinical Importance: eA was the best predictor of the presence or history of CHF. Further studies are needed to determine the clinical implications of these findings for treatment decisions and prognosis determination.
  • K. Nakamura, S. Kawamoto, T. Osuga, T. Morita, N. Sasaki, K. Morishita, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 31 2 316 - 325 2017年03月01日 [査読有り][通常論文]
     
    Background: Decreased function of the left atrium (LA) is a useful prognostic indicator in dogs with myxomatous mitral valve disease (MMVD). In humans, LA strain is a novel severity indicator of mitral regurgitation, but its clinical utility in dogs has not been confirmed. Objectives: To examine whether LA strain as evaluated with speckle-tracking echocardiography is associated with MMVD stage in dogs. Animals: Fifty-two client-owned dogs with MMVD. Methods: Cross-sectional study. Dogs were classified as stage B1, B2, C, or D, according to the American College of Veterinary Internal Medicine consensus. Physical examination findings and echocardiographic variables were compared among the groups. To assess the comparative accuracy of echocardiographic variables in identifying dogs with the presence or history congestive heart failure (CHF), receiver operating characteristic curves and multivariate logistic analysis were used. Results: There were no significant differences in parameters of LA strain between B1 and B2 groups. However, LA longitudinal strain during atrial contraction (εA) (median, 19.1% interquartile range, 15.3–24.3% in B1, 19.6% 14.1–21.4% in B2, 6.2% 3.18–11.2% in C/D) and during ventricular systole (εS) (32.7% 28.9–39.2% in B1, 35.6% 31.7–41.9% in B2, 23.6% 16.9–26.1% in C/D) were significantly lower in stages C/D than in stages B1 and B2. In multivariate logistic regression analysis, εA and peak early diastolic mitral inflow velocity were identified as independent indicators of stage C/D. Conclusions and Clinical Importance: εA was the best predictor of the presence or history of CHF. Further studies are needed to determine the clinical implications of these findings for treatment decisions and prognosis determination.
  • N. Yokoyama, H. Ohta, J. Yamazaki, Y. Kagawa, O. Ichii, N. Khoirun, T. Morita, T. Osuga, S. Y. Lim, N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi
    JOURNAL OF COMPARATIVE PATHOLOGY 156 2-3 183 - 190 2017年02月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) are characterized by the formation of multiple or solitary polyps with marked neutrophil infiltration in the colorectal area, and are speculated to be a novel form of breed-specific canine idiopathic inflammatory bowel disease (IBD). In human IBD, toll-like receptor (TLR) 2 and TLR4 have been reported to be involved in the pathogenesis of the disease. The aim of this study was to evaluate the expression of TLR2 and TLR4 mRNA in the colorectal mucosa of dogs with ICRPs by in-situ hybridization using an RNAscope assay. Samples of inflamed colorectal mucosa (n = 5) and non-inflamed mucosa (n = 5) from miniature dachshunds (MDs) with ICRPs and colonic mucosa from healthy beagles (n = 5) were examined. TLR2 and TLR4 hybridization signals were localized to the colorectal epithelium, inflammatory cells and fibroblasts in the inflamed colorectal mucosa of affected dogs. The signals were significantly greater in inflamed colorectal epithelium compared with non-inflamed epithelium of MDs with ICRPs and healthy beagles (P <0.05). These results suggest that increased expression of TLR2 and TLR4 mRNA in the inflamed colorectal mucosa results from not only inflammatory cell infiltration, but also the upregulation of TLR2 and TLR4 mRNA in the colonic epithelium. (C) 2016 Elsevier Ltd. All rights reserved.
  • 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 - 40340 2017年01月11日 [査読有り][通常論文]
     
    MicroRNAs act as post-transcriptional regulators, and urinary exosome (UExo)-derived microRNAs may be used as biomarkers. Herein, we screened for UExo-derived microRNAs reflecting kidney disease (KD) status in dogs. Examined dogs were divided into healthy kidney control (HC) and KD groups according to renal dysfunction. We confirmed the appearance of UExo having irregular globe-shapes in a dog by immunoblot detection of the exosome markers, TSG101 and CD9. Based on our previous data using KD model mice and the data obtained herein by next generation sequencing of UExo-derived microRNAs in dogs, miR-26a, miR-146a, miR-486, miR-21a, and miR-10a/b were selected as candidate microRNAs. In particular, UExo-derived miR-26a and miR-10a/b were significantly decreased in KD dogs, and miR-26a levels negatively correlated with deteriorated renal function compared to the other miRNAs. UExo-derived miR-21a levels corrected or not to that of internal control microRNAs in UExo, miR-26a and miR-191, significantly increased with renal dysfunction. In kidney tissues, the decrease of miR-26a and miR-10a/b in the glomerulus and miR-10b in the tubulointerstitium negatively correlated with deteriorated renal function and histopathology. Increased miR-21a in the tubulointerstitium rather than in the glomerulus correlated with deteriorated renal histopathology. In conclusion, microRNAs reflecting the changes in renal function and histopathology in dogs were identified in this study.
  • Keitaro Morishita, Akira Hiramoto, Tatsuyuki Osuga, Sue Yee Lim, Nisa Khoirun, Noboru Sasaki, Kensuke Nakamura, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 78 12 1753 - 1758 2017年01月10日 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography (CEUS) of the hepatic vein can assess intrahepatic hemodynamic changes and has been studied as a noninvasive method to assess the severity of portal hypertension and hepatic fibrosis in humans. However, few reports have described its usefulness in veterinary medicine. The purpose of this study was to characterize CEUS findings of the hepatic vein in normal dogs and assess the repeatability of this method both in a conscious group (n=6) and a sedated group (n=6). Sonazoid® (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.
  • Akiyoshi Tani, Jumpei Yamazaki, Kensuke Nakamura, Mitsuyoshi Takiguchi, Mutsumi Inaba
    Japanese Journal of Veterinary Research 65 4 201 - 206 2017年 [査読有り][通常論文]
     
    A one-year-old castrated male mixed-breed cat was referred for detailed examination of long-term pale mucous membrane without any clinical episodes that may cause cyanosis. While no causative abnormalities were detected in thoracic radiography and echocardiography, and arterial partial pressure of oxygen was within normal value, methemoglobin concentration of the cat was increased to 30% and cytochrome b5 reductase activity, which converts methemoglobin to hemoglobin, was reduced to 2.0 IU/gHb (13.4 ± 1.7 IU/gHb in control cats, n = 3), indicating congenital methemoglobinemia. Sequence analysis of CYB5R3, which codes cytochrome b5 reductase, showed two missense mutations found in the patient, one of which was predicted to affect protein function.
  • Noboru Sasaki, Kazuhiro Ishi, Nobuki Kudo, Shouta M M Nakayama, Kensuke Nakamura, Keitaro Morishita, Hiroshi Ohta, Mayumi Ishizuka, Mitsuyoshi Takiguchi
    PloS one 12 11 e0188093  2017年 [査読有り][通常論文]
     
    Non-muscle invasive bladder cancer is one of the most common tumors of the urinary tract. Despite the current multimodal therapy, recurrence and progression of disease have been challenging problems. We hereby introduced a new approach, ultrasound-assisted intravesical chemotherapy, intravesical instillation of chemotherapeutic agents and microbubbles followed by ultrasound exposure. We investigated the feasibility of the treatment for non-muscle invasive bladder cancer. In order to evaluate intracellular delivery and cytotoxic effect as a function to the thickness, we performed all experiments using a bladder cancer mimicking 3D culture model. Ultrasound-triggered microbubble cavitation increased both the intracellular platinum concentration and the cytotoxic effect of cisplatin at the thickness of 70 and 122 μm of the culture model. The duration of enhanced cytotoxic effect of cisplatin by ultrasound-triggered microbubble cavitation was approximately 1 hr. Based on the distance and duration of delivery, we further tested the feasibility of repetition of the treatment. Triple treatment increased the effective distance by 1.6-fold. Our results clearly showed spatial and temporal profile of delivery by ultrasound-triggered microbubble cavitation in a tumor-mimicking structure. Furthermore, we demonstrated that the increase in intracellular concentration results in the enhancement of the cytotoxic effect in a structure with the certain thickness. Repetition of ultrasound exposure would be treatment of choice in future clinical application. Our results suggest ultrasound-triggered microbubble cavitation can be repeatable and is promising for the local control of non-muscle invasive bladder cancer.
  • 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][通常論文]
     
    AIMS: To compare the survival of dogs with completely resected massive hepatocellular carcinoma (HCC) with that of dogs in which HCC were incompletely excised. METHODS: A retrospective cohort study was conducted. Dogs that underwent surgical excision of massive HCC between November 2006 and April 2015 were included. Dogs that died in the perioperative period or were lost to follow-up within 2 months after surgery were excluded. Data were collected from the medical records and a single pathologist examined all available histology slides to confirm the diagnosis of HCC. Surgical margins were defined as complete if no neoplastic cells were seen at the edge of excised tissues, based on original histopathology reports. Progression-free survival (PFS) and overall survival (OS) were compared between dogs with complete surgical margins (CM) and those with incomplete margins (IM) using a log-rank test. RESULTS: Of the 37 dogs included in the study, 25 were allocated to the CM group and 12 to the IM group. Progressive local disease developed after surgery in three dogs in the CM group and seven dogs in the IM group. Three dogs in the CM group and five dogs in the IM group died due to tumour progression. Median PFS was longer for dogs in the CM group (1,000 (95% CI=562-1,438) days) compared to dogs in the IM group (521 (95% CI=243-799) days; p=0.007). OS was also longer for dogs in the CM group (>1,836 days) compared to those in the IM group (median 765 (95% CI=474-1,056) days; p=0.02). CONCLUSIONS AND CLINICAL RELEVANCE: Compared with complete resection, incomplete resection decreased PFS and OS in dogs with massive HCC. Dogs with incompletely excised HCC should be closely monitored for local recurrence, although median OS was >2 years following incomplete excision. Further prospective studies are warranted to confirm these findings.
  • 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][通常論文]
     
    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.
  • Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Khoirun Nisa, Nozomu Yokoyama, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    American journal of veterinary research 77 9 952 - 60 2016年09月 [査読有り][通常論文]
     
    OBJECTIVE To elucidate the relationship between acute volume overload and left atrial phasic function in healthy dogs. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized. A Swan-Ganz catheter was placed to measure mean pulmonary capillary wedge pressure (PCWP). Cardiac preload was increased by IV infusion with lactated Ringer solution at 150 mL/kg/h for 90 minutes. Transthoracic echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after volume loading began. At each echocardiographic assessment point, apical 4-chamber images were recorded and analyzed to derive time-left atrial area curves. Left atrial total (for reservoir function), passive (for conduit function), and active (for booster-pump function) fractional area changes were calculated from the curves. RESULTS Volume overload resulted in a significant increase from baseline in PCWP from 15 to 90 minutes after volume loading began. All fractional area changes at 15 to 90 minutes were significantly increased from baseline. In multiple regression analysis, quadratic regression models were better fitted to the relationships between PCWP and each of the total and active fractional area changes than were linear regression models. A linear regression model was better fitted to the relationship between PCWP and passive fractional area change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that left atrial phasic function assessed on the basis of left atrial phasic areas was enhanced during experimental cardiac volume loading in healthy dogs. The effect of volume load should be considered when evaluating left atrial phasic function by indices derived from left atrial phasic sizes.
  • 活性型ビタミンD3軟膏使用中に飼い犬に腎不全をきたした尋常性乾癬の1例
    藤田 靖幸, 須藤 明日香, 清水 宏, 華園 究, 中村 健介, 内田 英二, 川畑 智敬
    日本皮膚科学会雑誌 126 9 1726 - 1726 (公社)日本皮膚科学会 2016年08月 [査読有り][通常論文]
  • Kensuke Nakamura, Nobuo Tohyama, Masahiro Yamasaki, Hiroshi Ohta, Keitaro Morishita, Mitsuyoshi Takiguchi
    JOURNAL OF THE AMERICAN ANIMAL HOSPITAL ASSOCIATION 52 4 256 - 258 2016年07月 [査読有り][通常論文]
     
    A miniature dachshund male with severe azotemia of unknown cause was referred. Serum biochemistry revealed severe azotemia and hypercalcemia, but serum intact parathormone and parathormone-related protein were normal. Although the owner reported that the dog had never ingested any drugs or supplements, it was revealed that the owner's son used antipsoriatic ointment, maxacalcitol, which contained an active vitamin D-3 analogue, daily and the dog often ate the son's dander and licked his skin, especially after he applied the maxacalcitol ointment. After the dog was insulated from the maxacalcitol ointment and the son as much as possible, the hypercalcemia and azotemia improved gradually and had mostly resolved at 3 mo. The dog has been generally free of clinical signs without any treatment for over 2 yr.
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Sue Yee Lim, Nozomu Yokoyama, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    American journal of veterinary research 77 7 715 - 20 2016年07月 [査読有り][通常論文]
     
    OBJECTIVE To evaluate repeatability and reproducibility of right ventricular Tei index (RTX) values derived from dual pulsed-wave Doppler, conventional pulsed-wave Doppler, and tissue Doppler echocardiography and to investigate relationships and repeatability among the 3 methods in healthy dogs. ANIMALS 6 healthy adult Beagles. PROCEDURE Echocardiography was performed on each dog on different days for 2 weeks (3 times/d) by 2 echocardiographers. Intraobserver within- and between-day and interobserver coefficients of variation (CVs) and intraclass correlation coefficients (ICCs) for RTXs derived from dual pulse-waved Doppler (RTXDPD), conventional pulsed-wave Doppler (RTXPD), and tissue Doppler (RTXTD) methods were determined. Degrees of agreement among RTX values derived from the 3 methods were assessed by modified Bland-Altman analysis. RESULTS Least squares mean (95% confidence interval) RTXtd was 0.50 (0.46 to 0.54), which was significantly higher than that for RTXDPD (0.27 [0.23 to 0.31]) and RTXPD (0.25 [0.21 to 0.29]). Agreement between RTXDPD and RTXPD was good (bias [mean difference], 0.04 [95% confidence interval, -0.03 to 0.10]). The RTXdpd had high within-day (CV, 6.1; ICC, 0.77) and interobserver (CV, 3.5; ICC, 0.83) repeatability, but between-day repeatability was not high. The RTXtd had high within-day repeatability (CV, 6.0; ICC, 0.80), but between-day and interobserver repeatability were not high. Within-day, between-day, and interobserver repeatability of RTXPD were not high. CONCLUSIONS AND CLINICAL RELEVANCE RTXdpd measurement was a repeatable and reproducible method of cardiac evaluation in healthy dogs. The RTXTD values were significantly higher than the RTXDPD and RTXPD values; therefore, RTX values derived from different echocardiographic methods should be interpreted with caution.
  • K. Nakamura, T. Morita, T. Osuga, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 30 1 69 - 75 2016年01月 [査読有り][通常論文]
     
    Background: The right ventricular (RV) Tei index (TX) has a significant correlation with the severity of pulmonary hypertension. However, the role of RV dysfunction in dogs with myxomatous mitral valvular heart disease (MMVD) has not been addressed. Objectives: To investigate the correlation between right ventricular Tei-index (RVTX) and the prognosis for dogs with MMVD. Animals: Thirty client-owned dogs with MMVD. Methods: Clinical cohort study. Dogs were divided into two groups on the basis of the onset of cardiac-related death within 1 year of the first echocardiographic examination. Physical examination and echocardiographic variables were compared between the groups. Receiver operating characteristic (ROC) curves and multivariate logistic analysis were used to assess the comparative accuracy when identifying dogs with cardiac-related death. Results: The highest accuracy was obtained for RVTX with an area under the ROC curve (AUC) of 0.95 (95% confidence interval [CI] 0.81-0.99) followed by the left atrial to aortic root ratio with an AUC of 0.91 (95% CI 0.74-0.98), peak early diastolic mitral inflow velocity with an AUC of 0.84 (95% CI 0.64-0.94), and Doppler estimates of systolic pulmonary artery pressure with an AUC of 0.84 (95% CI 0.61-0.95). According to the multivariate logistic regression analysis, RVTX was the only independent correlate of cardiac-related death within 1 year. Conclusions and Clinical Importance: Right ventricular Tei-index has a strong correlation with the prognosis for dogs with MMVD. The most significant independent predictor of death was RVTX in this study.
  • T. Osuga, K. Nakamura, T. Morita, S. Y. Lim, K. Nisa, N. Yokoyama, N. Sasaki, K. Morishita, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 29 6 1518 - 1523 2015年11月 [査読有り][通常論文]
     
    BackgroundIn humans with heart disease, vitamin D deficiency is associated with disease progression and a poor prognosis. A recent study showed that serum 25-hydroxyvitamin D [25(OH)D] concentration, the hallmark of vitamin D status, was lower in dogs with heart failure than in normal dogs, and a low concentration was associated with poor outcome in dogs with heart failure. ObjectivesTo elucidate the vitamin D status of dogs with chronic valvular heart disease (CVHD) at different stages of disease severity. AnimalsForty-three client-owned dogs with CVHD. MethodsIn this cross-sectional study, dogs were divided into 3 groups (14 dogs in Stage B1, 17 dogs in Stage B2, and 12 dogs in Stage C/D) according to ACVIM guidelines. Dogs underwent clinical examination including echocardiography. Serum 25(OH)D concentrations were measured in each dog. ResultsSerum 25(OH)D concentration was significantly lower in Stage B2 (median, 33.2nmol/L; range, 4.9-171.7nmol/L) and C/D (13.1nmol/L; 4.9-58.1nmol/L) than in Stage B1 (52.5nmol/L; 33.5-178.0nmol/L) and was not significantly different between Stage B2 and Stage C/D. Among clinical variables, there were significant negative correlations between 25(OH)D concentration and both left atrial-to-aortic root ratio and left ventricular end-diastolic diameter normalized for body weight. Conclusions and Clinical ImportanceThese results indicate that vitamin D status is associated with the degree of cardiac remodeling, and the serum 25(OH)D concentration begins to decrease before the onset of heart failure in dogs with CVHD.
  • 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 - 9 2015年08月 [査読有り][通常論文]
     
    OBJECTIVE: To evaluate the effects of dobutamine, esmolol, milrinone, and phenylephrine on left atrial phasic function of healthy dogs. ANIMALS: 9 healthy Beagles. PROCEDURES: Following sedation with propofol on each of 4 experimental days, dogs were administered a constant rate infusion of dobutamine (5 μg/kg/min), esmolol (500 μg/kg/min), milrinone (25 μg/kg, IV bolus, followed by 0.5 μg/kg/min), or phenylephrine (2 μg/kg/min). There was at least a 14-day interval between experimental days. Each drug was administered to 6 dogs. Conventional and 2-D speckle tracking echocardiography were performed before (baseline) and after administration of the cardiovascular drug, and time-left atrial area curves were derived to calculate indices for left atrial reservoir, conduit, and booster pump functions (left atrial phasic function) and left ventricular contractility and lusitropy. RESULTS: Compared with baseline values, indices for left atrial reservoir and booster pump functions and left ventricular contractility and lusitropy were significantly increased following dobutamine administration; indices for left atrial phasic function and left ventricular lusitropy were changed insignificantly, and indices for left ventricular contractility were significantly impaired following esmolol administration; indices for left atrial phasic function and left ventricular relaxation were changed insignificantly, and indices for left ventricular systolic function were significantly augmented following milrinone administration; and indices for left atrial phasic function and left ventricular lusitropy were changed insignificantly, and indices of ventricular contractility were significantly impaired following phenylephrine administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that, following administration of dobutamine, esmolol, milrinone, or phenylephrine to healthy dogs, left atrial phasic function indices were fairly stable and did not parallel changes in left ventricular function indices.
  • S. Y. Lim, K. Nakamura, K. Morishita, N. Sasaki, M. Murakami, T. Osuga, N. Yokoyama, H. Ohta, M. Yamasaki, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 29 1 71 - 78 2015年01月 [査読有り][通常論文]
     
    Background: Quantitative contrast-enhanced ultrasonography ( CEUS) can detect pancreatic perfusion changes in experimentally induced canine pancreatitis. However, its usefulness in detecting perfusion changes in naturally occurring pancreatitis is unclear. Hypothesis/ Objectives: To determine the feasibility of using CEUS to detect pancreatic and duodenal perfusion changes in naturally occurring canine pancreatitis. Animals: Twenty-three client-owned dogs with pancreatitis, 12 healthy control dogs. Methods: Dogs diagnosed with pancreatitis were prospectively included. CEUS of the pancreas and duodenum were performed. Time-intensity curves were created from regions of interest in the pancreas and duodenum. Five perfusion parameters were obtained for statistical analyses: time to initial up-slope, peak time ( Tp), time to wash-out ( TTW), peak intensity ( PI), and area under the curve ( AUC). Results: For the pancreas, Tp of the pancreatitis group was prolonged when compared to controls ( 62 +/- 11 seconds versus 39 +/- 13 seconds; P <.001). TTW also was prolonged but not significantly ( 268 +/- 69 seconds versus 228 +/- 47 seconds; P =.47). PI and AUC were increased when compared to controls ( 95 +/- 15 versus 78 +/- 13 MPV; P =.009 and 14,900 +/- 3,400 versus 11,000 +/- 2,800 MPV* s; P =.013, respectively). For the duodenum, PI and AUC were significantly increased in the pancreatitis group when compared to controls. Conclusions and Clinical Importance: Contrast-enhanced ultrasonography can detect pancreatic perfusion changes in naturally occurring canine pancreatitis characterized by delayed peak with prolonged hyperechoic enhancement of the pancreas on CEUS. Additionally, duodenal perfusion changes secondary to pancreatitis were observed.
  • 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][通常論文]
     
    Abdominal ultrasonography is one of the most common diagnostic imaging modalities used for dogs with suspected insulinoma; however, pancreatic masses are clearly identified in fewer than half of affected dogs and benign pancreatic nodules can be difficult to differentiate from malignant ones. The purpose of this prospective study was to describe contrast-enhanced ultrasonography (CEUS) characteristics of confirmed pancreatic insulinoma in a group of dogs. Inclusion criteria were as follows: (1) repeated hypoglycemia (blood glucose levels <60 mg/dl, twice or more); (2) elevated blood insulin levels with hypoglycemia; (3) pancreatic nodules detected with conventional ultrasonography; and (4) histological confirmation of pancreatic islet cell carcinoma. Immediately following conventional ultrasonography of the entire abdomen, CEUS of the pancreatic nodule and adjacent parenchyma was performed using contrast-specific technology pulse inversion imaging and perflubutane microbubble contrast agent. Three dogs met inclusion criteria. Pancreatic nodules in all the three dogs became more clearly demarcated after injection of the contrast agent. Each nodule showed different enhancement patterns: markedly hyperechoic for 5 s, slightly hyperechoic for 1 s, and clearly hypoechoic for over 30 s. These results were not in complete agreement with previously reported CEUS findings in human patients with insulinoma. All nodules were surgically resected and histopathologically confirmed as malignant insulinomas. Findings from the current study indicated that contrast-enhanced ultrasound may help to increase conspicuity of pancreatic insulinomas in dogs and that enhancement characteristics may be more variable in dogs than in humans. (C) 2014 American College of Veterinary Radiology.
  • 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][通常論文]
     
    One of the major applications of contrast-enhanced ultrasound (CEUS) is lesion classification. After contrast agents are administered, it is possible to identify a lesion type from its enhancement pattern. However, CEUS image reading is not easy because there are various types of enhancement patterns even for the same type of lesion, and clear classification criteria have not yet been defined. Some studies have used conventional time intensity curves (TICs), which show the vessel dynamics of a lesion. It is possible to predict lesion type from the TIC parameters, such as the coefficients obtained by curve fitting, peak intensity, flow rate and time to peak. However, these parameters are not always provide sufficient accuracy. In this paper, we prepare 1D Haar-like features which describe intensity changes in a TIC and adopt the Adaboost machine learning technique, which eases understanding of which features are useful. Hyperparameters of weak classifiers, e.g., the step size of a Haar-like filter length and threshold for output of the filter, are optimized by searching for those parameters that give the best accuracy. We evaluate the proposed method using 36 focal splenic lesions in canines 16 of which were benign and 20 malignant. The accuracies were 91.7% (33/36) when inspected by an experienced veterinarian, 75.0% (27/36) by linear discriminant analysis (LDA) using conventional three TIC parameters: time to peak, area under curve and peak intensity, and 91.7% (33/36) using our proposed method. McNemar testing shows the p-value to be less than 0.05 between the proposed method and LDA. This result shows the statistical significance of differences between the proposed method and the conventional TIC analysis method using LDA.
  • K. Nakamura, T. Osuga, K. Morishita, S. Suzuki, T. Morita, N. Yokoyama, H. Ohta, M. Yamasaki, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 28 6 1746 - 1752 2014年11月 [査読有り][通常論文]
     
    BackgroundA strong correlation between left atrial (LA) dysfunction and the severity of cardiac disease has been described in human patients with various cardiac diseases. The role of LA dysfunction in dogs with chronic mitral valvular heart disease (CMVHD) has not been addressed. ObjectivesTo investigate the correlation between LA function and the prognosis of dogs with CMVHD. AnimalsThirty-eight client-owned dogs with CMVHD. MethodsProspective clinical cohort study. Dogs were divided into 2 groups (survivors and nonsurvivors) based on the onset of cardiac-related death within 1year. Physical examination and echocardiographic variables were compared between the groups. For the assessment of the comparative accuracy in identifying patients with cardiac-related death, receiver operating characteristic (ROC) curves and multivariate logistic analysis were used. ResultsThe highest accuracy was obtained for the LA active fractional area change (LA-FAC(act)), with an area under the ROC curve (AUC) of 0.95, followed by the left atrial to aortic root ratio (LA/Ao), with an AUC of 0.94; peak early diastolic mitral inflow velocity (E), with an AUC of 0.85; and LA total fractional area change (LA-FAC(total)), with an AUC of 0.85. In the multivariate logistic regression analysis, LA-FAC(act) emerged as the only independent correlate of cardiac-related death within 1year (odds ratio=1.401, P=.002). Conclusions and Clinical ImportanceRegarding both the size and function, the LA has a strong correlation with the prognosis of dogs with CMVHD. The most significant independent predictor of mortality in this study was LA-FAC(act).
  • 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 - 33 2014年10月15日 [査読有り][通常論文]
     
    Babesia gibsoni is a causative pathogen of canine babesiosis, which is commonly treated with anti-babesial drugs; however, the development of novel, more effective anti-babesial drugs is necessary because the currently used drugs cannot remove the parasites from dogs. Therefore we investigated the anti-babesial effect of amphotericin B (AmB), a membrane-active polyene macrolide antibiotic. The interaction of such compounds with sterols in bilayer cell membranes can lead to cell damage and ultimately cell lysis. AmB exhibits in vitro activity against B. gibsoni in normal canine erythrocytes within 12h. We also studied liposomal AmB (L-AmB), a liposomal formulation of AmB that required a longer incubation period to reduce the number of parasites. However, L-AmB completely inhibited the invasion of free parasites into erythrocytes. These results indicated that free parasites failed to invade erythrocytes in the presence of L-AmB. Both AmB and L-AmB induced mild hemolysis of erythrocytes. Moreover, the methemoglobin level and the turbidity index of erythrocytes were significantly increased when erythrocytes were incubated with AmB, suggesting that AmB induced oxidative damage in erythrocytes. Finally, the anti-babesial activity of AmB in vivo was observed. When experimentally B. gibsoni-infected dogs were administered 0.5 and 1mg/kg AmB by the intravenous route, the number of parasites decreased; however, recurrence of parasitemia was observed, indicating that AmB did not eliminate parasites completely. Blood urea nitrogen and creatinine of dogs were abnormally elevated after the administration of 1mg/kg AmB. These results indicate that AmB has in vivo activity against B. gibsoni; however, it does not eliminate parasites from infected dogs and affects kidney function at a high dose.
  • Yu Tamura, Hiroshi Ohta, Nozomu Yokoyama, Sue Yee Lim, Tatsuyuki Osuga, Keitaro Morishita, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 76 10 1407 - 10 2014年10月 [査読有り][通常論文]
     
    Lymphocytic-plasmacytic colitis (LPC) is a common form of inflammatory bowel disease (IBD) affecting the canine large intestine. Cytokines are thought to be involved in the pathogenesis of IBD. However, to date, few studies have investigated cytokine mRNA expression in dogs with LPC. In this study, we investigated mRNA transcription levels of T helper cell cytokines, such as IFN-γ, IL-4, IL-17 and IL-10 and pro-inflammatory cytokines, such as IL-1β, IL-6, TNF-α, IL-8, IL-12 and IL-23, in colonic mucosa from LPC dogs by quantitative real-time RT-PCR. No significant differences were detected in cytokine mRNA expressions between dogs with LPC and controls, except for IL-23p19. Dogs with LPC failed to express a predominant cytokine profile in inflamed colonic mucosa as opposed to human IBD.
  • 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 - 5 2014年09月15日 [査読有り][通常論文]
     
    An eight-year-old, neutered, female Shetland Sheepdog presented with a 6-week history of small intestinal diarrhea. Regenerative anemia, hypoproteinemia, and an increased plasma C-reactive protein concentration were detected on blood examination. Fecal examination and abdominal radiography were unremarkable. Abdominal ultrasonography showed diffusely hyperechoic mucosa in the small intestine. Gastroduodenoscopy, performed under general anesthesia, revealed mucosal edema and increased granularity in the duodenum and jejunum. Histopathological examination of the endoscopically biopsied small intestinal mucosa revealed tapeworm infection. A single administration of a combined anthelmintic drug (5mg/kg praziquantel, 14.4 mg/kg pyrantel pamoate, and 15 mg/kg febantel) was successful for deworming, and the dog fully recovered. The parasites were removed from stored frozen duodenal mucosa and morphologically identified as Mesocestoides sp. immature adult worms. Mitochondrial (mt) 12S rDNA and mt cytochrome c oxide subunit 1 genes were amplified from the parasites. DNA sequence analysis showed that the genes shared 100% identity with those of reported M. vogae (syn. M. corti). This is the first reported case of protein-losing enteropathy caused by M. vogae in a dog.
  • 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 - 51 2014年08月 [査読有り][通常論文]
     
    OBJECTIVE: To determine the expression of tight junction and adherens junction proteins in duodenal mucosa samples of dogs with inflammatory bowel disease (IBD). ANIMALS: 12 dogs with IBD and 6 healthy control Beagles. PROCEDURES: Duodenal mucosa biopsy samples were endoscopically obtained from dogs with IBD and healthy control Beagles. The expression of claudin-1, -2, -3, -4, -5, -7, and -8; E-cadherin; and β-catenin in the duodenal mucosa samples was determined by means of immunoblotting. The subcellular localization of E-cadherin in the duodenal mucosa samples was determined with immunofluorescence microscopy. RESULTS: The expression of each claudin and β-catenin was not significantly different between control dogs and dogs with IBD. However, expression of E-cadherin was significantly lower in duodenal mucosa samples of dogs with IBD than it was in samples obtained from healthy control dogs. Results of immunofluorescence microscopy indicated decreased intensity of E-cadherin labeling in the tips of villi in duodenal mucosa samples obtained from 6 dogs with IBD, compared with staining intensity for other dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study indicated expression of claudin-1, -2, -3, -4, -5, -7, and -8 and β-catenin was not significantly different between duodenal mucosa samples obtained from control dogs and those obtained from dogs with IBD. However, E-cadherin expression was significantly lower in the villus epithelium in duodenal mucosa samples obtained from dogs with IBD versus samples obtained from control dogs, which suggested that decreased expression of that protein has a role in the pathogenesis of IBD 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][通常論文]
     
    Background Acute pancreatitis (AP) is the most common disease of the canine exocrine pancreas, and accurate noninvasive diagnosis is challenging. Hypothesis/Objectives To determine the feasibility of using quantitative contrast-enhanced ultrasonography (CEUS) to detect pancreatic perfusional changes in cerulein-induced AP in dogs. Animals Six adult female Beagles. Methods Each dog received 2hours of IV infusion with 7.5 mu g/kg/h of cerulein diluted in saline. As control, all dogs received 2hours of IV infusion of saline 2weeks before cerulein infusion. CEUS of the pancreas and duodenum were performed before (0hour), and at 2, 4, 6, and 12hours after saline and cerulein infusion. Time-intensity curves were created from regions of interest in the pancreas and duodenum. Five perfusional parameters were measured for statistical analysis: time to initial up-slope, peak time, time to wash-out, peak intensity (PI), and area under the curve (AUC). Results In cerulein-induced AP, pancreatic PI increased at 2 and 4hours when compared to 0hour, and at 2, 4, and 6hours when compared to control. AUC increased at 4hours when compared to 0hour, and at 2 and 4hours when compared to control. Time to wash-out was prolonged at 4hours when compared to control. For saline control, peak time was faster at 2hours when compared to 0hour. Conclusions and Clinical Importance CEUS parameters PI and AUC can provide useful information in differentiating acute pancreatitis from normal pancreas. Cerulein-induced AP was characterized by prolonged hyperechoic enhancement on CEUS.
  • 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 - 14 2014年03月 [査読有り][通常論文]
     
    Inflammatory bowel disease (IBD) is a common cause of chronic gastrointestinal signs in dogs. In humans, T helper cells have important roles in the pathogenesis of IBD. In contrast, no specific involvement of a distinct T cell subset has been described in canine IBD. The present study evaluated the gene and protein expression of cytokines of T cell subsets in duodenal mucosa from dogs with IBD. Relative quantification of interleukin (IL)-17A, interferon (IFN)-γ, IL-4 and IL-10 mRNA transcription was performed using duodenal mucosa from 27 IBD dogs and 8 controls. Duodenal mucosal IL-17A, IFN-γ and IL-10 protein levels were determined by ELISA in 15 IBD dogs and 8 controls. There was no significant difference in each cytokines mRNA transcription level between groups. There was no significant difference in IL-17A, IFN-γ and IL-10 protein expression levels between groups. Thus, there is no clear evidence for the involvement of distinct Th cytokine in the pathogenesis of canine IBD.
  • Noboru Sasaki, Nobuki Kudo, Kensuke Nakamura, Sue Yee Lim, Masahiro Murakami, W R Bandula Kumara, Yu Tamura, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    Journal of medical ultrasonics (2001) 41 1 11 - 21 2014年01月 [査読有り][通常論文]
     
    PURPOSE: The aim of this study was to clarify whether ultrasound image-guided cisplatin delivery with an intratumor microbubble injection enhances the antitumor effect in a xenograft mouse model. METHODS: Canine thyroid adenocarcinoma cells were used for all experiments. Before in vivo experiments, the cisplatin and microbubble concentration and ultrasound exposure time were optimized in vitro. For in vivo experiments, cells were implanted into the back of nude mice. Observed by a diagnostic ultrasound machine, a mixture of cisplatin and ultrasound contrast agent, Sonazoid, microbubbles was injected directly into tumors. The amount of injected cisplatin and microbubbles was 1 μg/tumor and 1.2 × 10(7) microbubbles/tumor, respectively, with a total injected volume of 20 μl. Using the same diagnostic machine, tumors were exposed to ultrasound for 15 s. The treatment was repeated four times. RESULTS: The combination of cisplatin, microbubbles, and ultrasound significantly delayed tumor growth as compared with no treatment (after 18 days, 157 ± 55 vs. 398 ± 49 mm(3), P = 0.049). Neither cisplatin alone nor the combination of cisplatin and ultrasound delayed tumor growth. The treatment did not decrease the body weight of mice. CONCLUSION: Ultrasound image-guided anticancer drug delivery may enhance the antitumor effects of drugs without obvious side effects.
  • Sue Yee Lim, Kensuke Nakamura, Keitaro Morishita, Noboru Sasaki, Masahiro Murakami, Tatsuyuki Osuga, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 75 12 1601 - 7 2013年12月30日 [査読有り][通常論文]
     
    Quantitative contrast enhanced ultrasound is a major breakthrough for ultrasound imaging in recent years. However, contrast enhancement of the pancreas is brief with bolus injection. To assess if continuous infusion of Sonazoid(®) can prolong the duration of pancreatic enhancement over bolus injections, eight adult dogs received bolus injection and continuous infusion of Sonazoid(®) on separate days. Contrast enhanced ultrasound of the pancreatic parenchyma and proximal descending duodenum was performed, and time intensity curves reflecting tissue perfusions were generated. Perfusion parameters- time to initial upslope, peak time, time to wash-out and peak intensity were calculated and evaluated. Fast wash-in to intense peak, followed by rapid wash-out was observed for time intensity curves of bolus injection. With continuous infusion, contrast wash-in to peak intensity was gradual, followed by long plateau and slow wash-out. Median contrast enhancement durations of the pancreas and duodenum were significantly prolonged by continuous infusion from 11 sec (range, 10 to 23 sec) and 16 sec (range, 3 to 43 sec) at bolus injection to 205 sec (range, 170 to 264 sec, P<0.01) and 193 sec (range, 169 to 216 sec, P<0.05), respectively. Median peak intensity of the pancreas was 100.9 MPV (range, 80.2 to 124.3 MPV) at bolus injection and 77.6 MPV (range, 58.2 to 99.5 MPV, P<0.05) at continuous infusion. Prolonged continuous imaging is afforded by continuous infusion of contrast agent. Peak intensity of the pancreas was slightly diminished in continuous infusion, but offered adequate imaging subjectively.
  • 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15日 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds were recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and/or space-occupying large polyps in the colorectal area and are thought to be a novel form of inflammatory bowel disease (IBD). To explore key mediators in the pathogenesis of ICRPs, we analyzed several pro-inflammatory cytokine (IL-1β, IL-6, TNF-α, IL-8, IL-12p35, IL-12/23p40, and IL-23p19) mRNA expressions in colorectal polyps in ICRP dogs by quantitative PCR. Among these cytokines, IL-8 mRNA expression was markedly up-regulated in large polyps. To examine IL-8 protein expression, we analyzed IL-8 protein level and its location in colorectal mucosal specimens of ICRP dogs by ELISA and immunofluorescence microscopy. IL-8 protein was significantly increased in large polyps and serum in dogs with ICRPs compared to controls. By immunofluorescence microscopy, IL-8 was only localized in macrophages, but not in mucosal epithelial cells or neutrophils. IL-8-positive macrophages were significantly increased in large polyps compared to controls. These results suggest that IL-8 is produced mainly by macrophages and may induce neutrophil infiltration in the colorectal area of ICRP dogs.
  • 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 - 63 2013年10月01日 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds are recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and a space-occupying large polyp in the colorectal area, and are thought to be a novel form of inflammatory bowel disease (IBD). In humans, specific cytokine patterns attributed to T helper (Th)1, Th17 and regulatory T cells have important roles in the pathogenesis of IBD. Thus, the aim of the present study was to assess the gene expression of cytokines of T cell subsets in the colorectal mucosa from dogs with ICRPs. Colorectal mucosal specimens from 10 dogs with ICRPs and 14 control dogs were used in this study. Interferon (IFN)-γ, interleukin (IL)-4, IL-17A and IL-10 mRNA expression was assessed using quantitative real-time PCR. IL-17A mRNA expression was significantly increased in large polyps compared to small polyps and controls. IFN-γ and IL-10 mRNA expression in large polyps were significantly higher than in controls. There was no significant difference in IL-4 mRNA expression among the three groups. IL-17A is thought to play important roles in the pathogenesis of ICRPs. IL-10 up-regulation could oppose the proinflammatory function of IL-17A.
  • 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 - 9 2013年06月 [査読有り][通常論文]
     
    OBJECTIVE: To evaluate left atrial phasic function in healthy dogs by means of 2-D speckle tracking echocardiography with time-left atrial area curve analysis and to assess repeatability and reproducibility of obtained measurements. ANIMALS: 6 healthy Beagles. PROCEDURES: Each dog underwent echocardiography twice on different days (3 nonconsecutive examinations/d). Images were analyzed with offline software; area of the left atrium was automatically calculated in each frame throughout the cardiac cycle to derive time-left atrial area curves. Variables used to assess left atrial phasic function (total, passive, and active emptying area and emptying fractions and mean active and total emptying rates) were calculated. Agreement between variables measured via speckle tracking echocardiography and a manual tracing method was assessed with modified Bland-Altman analysis. Within-day and between-day coefficients of variation were determined. RESULTS: Mean ± SD total, passive, and active emptying fractions of the left atrium were 49.8 ± 3.5%, 277 ± 4.0%, and 30.5 ± 4.3%, respectively. Mean ± SD total and active emptying rates were 16.0 ± 2.5 cm(2)/s and 25.1 ± 4.9 cm(2)/s, respectively. Within-day and between-day coefficients of variation were < 20% (range, 0.41% to 16.4%) for all variables except mean active emptying rate (between-day coefficient of variation, 29.2%). Agreement between variables measured via speckle tracking echocardiography and the manual tracing method was good, and differences between methods were nonsignificant. CONCLUSIONS AND CLINICAL RELEVANCE: Evaluation of left atrial phasic function via speckle tracking echocardiography was feasible; repeatability and reproducibility of measurements were adequate in healthy dogs. Studies are needed to determine clinical applicability in canine patients.
  • Bandula Kumara Wickramasekara Rajapakshage, Masahiro Yamasaki, Shiang-Jyi Hwang, Noboru Sasaki, Masahiro Murakami, Yu Tamura, Sue Yee Lim, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 74 9 1139 - 48 2012年09月 [査読有り][通常論文]
     
    The stability of the characteristics of the diminazene aceturate (DA)-resistant B. gibsoni isolate was initially determined in vitro. Part of the DA-resistant B. gibsoni isolate was cultured without DA for 4 weeks, and then newly exposed to 200 ng/ml DA. As a result, this isolate could proliferate the same as the DA-resistant isolate, indicating that the characteristic of DA resistance was stable in the DA-resistant isolate. Additionally, the level of parasitemia in the DA-resistant isolate was comparatively lower than in the wild-type, suggesting that the proliferation potential of the DA-resistant isolate would be lower than that of the wild-type. Subsequently, to investigate the involvement of mitochondrial DNA (mtDNA) in DA resistance in B. gibsoni, the nucleotide sequences and deduced amino acid sequences of mitochondrial genes such as COXI, COXIII, and CYTb genes of the DA-resistant isolate, were compared with those of the wild-type. As a result, these three genes were not altered in the DA-resistant B. gibsoni isolate. Moreover, the transcription levels of COXI, COXIII, and CYTb genes were observed by semi-quantitative RT-PCR. As a result, the gene transcription of those genes in the DA-resistant isolate was not significantly altered. These results indicated that DA did not affect mtDNA directly in DA-resistant B. gibsoni. Thus, it is suggested that mtDNA should not be deeply involved in DA resistance in B. gibsoni.
  • Kensuke Nakamura, Masahiro Yamasaki, Tomohiro Osaki, Hiroshi Ohta, Noboru Sasaki, Keisuke Aoshima, Takashi Kimura, Mitsuyoshi Takiguchi
    JOURNAL OF THE AMERICAN ANIMAL HOSPITAL ASSOCIATION 48 5 327 - 330 2012年09月 [査読有り][通常論文]
     
    Bilateral segmental aplasia of the uterine horns with unilateral pyometra and uterine horn torsion were diagnosed in a Pomeranian bitch that presented with chronic abdominal distension and an acute onset of anorexia and lethargy. Because radiographic and ultrasonographic findings revealed the presence of markedly enlarged bilateral uterine horns filled with fluid in the caudal abdomen, a tentative diagnosis of either pyometra or hydrometra with uterine horn torsion was made. Exploratory laparotomy showed bilateral, segmentally distended uterine horns with unilateral uterine horn torsion. Ovariohysterectomy was performed, and bilateral segmental aplasia of the uterine horns with the development of unilateral uterine horn torsion was diagnosed histopathologically. To the authors' knowledge, this is the first report of uterine horn torsion in conjunction with segmental aplasia of the uterine horn in a bitch. (J Am Anim Hosp Assoc 2012; 48:327-330. DOI 10.5326/JAAHA-MS-5771)
  • Bandula Kumara Wickramasekara Rajapakshage, Masahiro Yamasaki, Masahiro Murakami, Yu Tamura, Sue Yee Lim, Tatsuyuki Osuga, Noboru Sasaki, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Japanese journal of veterinary research 60 2-3 51 - 61 2012年08月 [査読有り][通常論文]
     
    In our previous study, the level of parasitemia of the diminazene aceturate (DA)-resistant B. gibsoni isolate was continuously lower than that of the wild-type, indicating the possible alteration of energy metabolism in that isolate. Therefore, in the present study, the concentrations of ATP, glucose, lactate, and pyruvate, and the activities of lactate dehydrogenase and pyruvate kinase in the wild-type and DA-resistant isolate of B. gibsoni were measured and compared to investigate the amount of energy generation and the activity of the glycolysis pathway. As a result, the intracellular ATP and glucose concentrations in the DA-resistant B. gibsoni isolate were significantly higher than those in the wild-type. Meanwhile, the concentrations of lactate and pyruvate and the activities of lactate dehydrogenase and pyruvate kinase in the DA-resistant B. gibsoni isolate were not different from those in the wild-type. These results indicated that the DA-resistant B. gibsoni isolate contained a higher ATP concentration than the wild-type, but the activity of the glycolysis pathway was not altered in the DA-resistant B. gibsoni isolate. However, we could not determine the mechanism of the high energy production of the DA-resistant B. gibsoni isolate. Further studies on the energy metabolism of B. gibsoni are necessary to clarify the mechanism of the high energy production in the DA-resistant B. gibsoni isolate.
  • 中村健介
    北海道獣医師会雑誌 56 2 37 - 41 2012年02月 [査読無し][招待有り]
  • Noboru Sasaki, Nobuki Kudo, Kensuke Nakamura, Sue Yee Lim, Masahiro Murakami, W R Bandula Kumara, Yu Tamura, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    Ultrasound in medicine & biology 38 1 109 - 18 2012年01月 [査読有り][通常論文]
     
    Ultrasound targeted microbubble destruction has succeeded in delivering drugs and genes. This study was designed to explore characteristics of ultrasound targeted microbubble destruction using short-pulsed diagnostic ultrasound. Canine thyroid adenocarcinoma cells were exposed to short-pulsed diagnostic ultrasound in the presence of cis-diamminedichloroplatinum (II) (cisplatin) and ultrasound contrast agent Sonazoid(®) microbubbles. The cytotoxic effect of cisplatin was enhanced by short-pulsed diagnostic ultrasound and microbubbles. Incubation time with microbubbles influenced the cytotoxic effect of cisplatin. However, exposure duration did not affect the cytotoxic effect of cisplatin. Therefore, short-pulsed diagnostic ultrasound may activate microbubbles near cells and deliver cisplatin into cells. In addition, activation of microbubbles may be concluded in a short time. Our results suggest that short exposure duration could be potentially sufficient to induce efficient drug delivery by ultrasound targeted microbubble destruction using short-pulsed diagnostic ultrasound.
  • Noboru Sasaki, Kensuke Nakamura, Masahiro Murakami, Sue Yee Lim, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    11TH INTERNATIONAL SYMPOSIUM ON THERAPEUTIC ULTRASOUND 1481 307 - 310 2012年 [査読有り][通常論文]
     
    Diagnostic ultrasound has accomplished drug and gene delivery by ultrasound targeted microbubble destruction (UTMD). However, the efficacy of delivery is still relatively low. Therefore, we optimized conditions of UTMD using diagnostic ultrasound and ultrasound contrast agent microbubbles. Canine thyroid adenocarcinoma cells were cultured in a 96-well plate. After addition of cisplatin and Sonazoid (R), the plate was inverted to raise microbubbles near cells and incubated. Cells were exposed to diagnostic ultrasound using a linear probe operated in the contrast harmonic imaging mode. The center frequency was 2.5 MHz with a mechanical index of 1.33 and a frame rate of 48 frames/sec. Cytotoxic effect of cisplatin was evaluated 24h after exposure using trypan blue dye exclusion test. We optimized incubation duration, cisplatin concentration, and the relationship between microbubble concentration and exposure duration. The optimum enhancement was observed at incubation duration of 5min, cisplatin concentration of 1 mu g/ml, and microbubble concentration of 2.4 x 10(5) microbubbles/ml. Exposure duration did not influence the enhancement at the microbubble concentration of 2.4 x 10(5) microbubbles/ml. Our results suggest that relative low concentrations of drug and microbubbles with short exposure duration might be sufficient for drug delivery by UTMD using diagnostic ultrasound.
  • Masahiro Yamasaki, Norihisa Tamura, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Wickramasekara Rajapakshage, Bandula Kumara, Yu Tamura, Sue Yee Lim, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of parasitology 97 6 1190 - 2 2011年12月 [査読有り][通常論文]
     
    Nystatin is a membrane-active polyene macrolide antibiotic and a channel-forming ionophore. Nystatin exhibits in vitro activity against Babesia gibsoni infecting normal canine erythrocytes containing low potassium (LK) and high sodium concentrations, i.e., LK erythrocytes. The calculated IC(50) value of nystatin against B. gibsoni infecting LK erythrocytes was 31.96 µg/ml. The anti-babesial activity of nystatin disappeared when B. gibsoni in LK erythrocytes were incubated in culture media containing high potassium concentrations (HK). Moreover, when the parasites were harbored in canine HK erythrocytes, which contained high potassium and low sodium concentrations as a result of high Na-K-ATPase activity, the in vitro anti-babesial activities of nystatin also disappeared, apparently due to protection by HK erythrocytes. This suggested that nystatin could show in vitro anti-babesial activity against B. gibsoni by its ionophorous activity, the same as other ionophores such as valinomycin. Subsequently, the effects of nystatin on the host cells were observed. Nystatin could not modify the intracellular concentrations of potassium, sodium, adenosine triphosphate, or glucose in either LK or HK erythrocytes, although it caused weak hemolysis in HK erythrocytes. In addition, nystatin did not affect the survival of canine peripheral polymorphonuclear leukocytes. In conclusion, nystatin destroyed B. gibsoni by ionophorous activity but did not affect either canine erythrocytes or leukocytes in vitro.
  • K. Nakamura, M. Yamasaki, H. Ohta, N. Sasaki, M. Murakami, W. R. Bandula Kumara, M. Takiguchi
    JOURNAL OF SMALL ANIMAL PRACTICE 52 11 595 - 598 2011年11月 [査読有り][通常論文]
     
    Objectives: To determine the effect of sildenafil for dogs with Eisenmeger's syndrome and secondary erythrocytosis.
  • 千葉 依里, 山崎 真大, 大田 寛, 中村 健介, 佐々木 東, 村上 正絋, 田村 悠, Lim Sue Yee, Kumara Wickramasekara Rajapakshage Bandula, 本田 英隆, 那須野 豊彦, 落合 謙爾, 滝口 満喜
    獣医臨床皮膚科 17 3 177 - 182 (一社)日本獣医皮膚科学会 2011年09月 [査読有り][通常論文]
  • 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 - 25 2011年08月25日 [査読有り][通常論文]
     
    Antibodies that recognized either Babesia gibsoni or canine red blood cell (RBC) 70-kilodalton (kDa) protein were detected in serum from acutely and chronically B. gibsoni-infected. In those sera, antibodies that reacted with recombinant B. gibsoni and canine heat shock protein 70 (rBgHsp70 and rcHsp70) were detected; therefore, B. gibsoni and canine RBC 70-kDa proteins seemed to be BgHsp70 and cHsp70, respectively. In infected dogs, the amounts of these antibodies increased after infection. Interestingly, polyclonal antibody raised against rBgHsp70 in two rabbits reacted not only with rBgHsp70 but also with rcHsp70 and native cHsp70 from canine RBCs. Because BgHsp70 showed high homology with cHsp70 (70.8%), anti-rBgHsp70 antibody might cross-react with cHsp70. Additionally, the localizations of both BgHsp70 and cHsp70 were observed by indirect fluorescence assay. As a result, cHsp70 was not found on the membrane surface of erythrocytes, suggesting that erythrocytes would not be targets of anti-cHsp70 antibody. Meanwhile, only exoerythrocytic parasites were stained by anti-rBgHsp70 antibody. This result showed that BgHsp70 would be expressed on the surface of parasites during the exoerythrocytic stage. These results indicated that BgHsp70 was a highly immunogenic protein in canine B. gibsoni infection, and that exoerythrocytic parasites might be targets of anti-BgHsp70 antibody.
  • 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 - 51 2011年08月 [査読有り][通常論文]
     
    OBJECTIVE: To examine the expression and distribution of tight junction (TJ) and adherens junction (AJ) proteins in canine duodenal and colonic mucosa. SAMPLE: Mucosa obtained from 4 healthy Beagles. PROCEDURES: Biopsy specimens of the duodenum and colon were obtained via endoscopy from 4 healthy dogs. The expression patterns and subcelluar localization of claudin-1, -2, -3, -4, -5, -7, and -8; E-cadherin; and β-catenin in the duodenum and colon were analyzed by use of immunoblotting and immunofluorescence microscopy. RESULTS: In the duodenum, there was clear expression of claudin-3 and -5, E-cadherin, and β-catenin proteins and weak expression of claudin-7 protein. In contrast, there was clear expression of claudin-2 and -3, E-cadherin, and β-catenin proteins and weak expression of claudin-5 and -7 proteins in the colon, as determined by use of immunoblotting. As determined by the use of immunofluorescence microscopy, the duodenum and colon had staining for claudin-3 and -5, E-cadherin, and β-catenin in the most apical region and staining for claudin-7 in the basolateral region. Staining for claudin-2 was also observed in the colon. CONCLUSIONS AND CLINICAL RELEVANCE: Information was provided about the expression patterns of TJ and AJ proteins in the duodenum and colon of clinically normal dogs. These results may provide valuable information for use in evaluating the importance of these TJ and AJ proteins in the pathogenesis of inflammatory bowel disease in dogs.
  • 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 - 26 2011年01月 [査読有り][通常論文]
     
    In this study, we attempted to detect Babesia gibsoni in blood smears and formalin-fixed, paraffin-embedded tissues obtained from B. gibsoni-infected dogs using in situ hybridization. Using a digoxigenin-conjugated deoxyribonucleic acid (DNA) probe, both intraerythrocytic and exoerythrocytic parasites in the culture could be specifically stained in blood smears fixed with 4% phosphate-buffered paraformaldehyde. This indicated that genomic DNA extracted from the parasites could be detected using in situ hybridization. Moreover, the parasite could be specifically stained in paraffin-embedded spleen, lymph node, and kidney sections using in situ hybridization. Infected erythrocytes in blood vessels in the spleen and kidney, hemosiderin-laden macrophages in the spleen, and phagocytized erythrocytes, which seemed to be infected with the parasites, in lymph nodes were also specifically stained. This suggests that in situ hybridization can be utilized to investigate both the life cycle of B. gibsoni and the pathological condition of canine babesiosis.
  • K. Nakamura, N. Sasaki, M. Murakami, W. R. Bandula Kumara, H. Ohta, M. Yamasaki, S. Takagi, T. Osaki, M. Takiguchi
    JOURNAL OF VETERINARY INTERNAL MEDICINE 24 6 1290 - 1297 2010年11月 [査読有り][通常論文]
     
    Background: Contrast-enhanced ultrasonography with perflubutane microbubbles improves the diagnostic accuracy to differentiate benign and malignant focal liver lesions in dogs. Hypothesis: Perflubutane microbubbles-enhanced ultrasonography is useful for differentiation of benign from malignant focal splenic lesions in dogs. Animals: Twenty-nine clinical dogs with single or multiple focal splenic lesions detected by conventional ultrasonography. Methods: Prospective clinical observational study. Perflubutane microbubbles-enhanced ultrasonography was performed in 29 dogs with focal splenic lesions. Qualitative assessment of the enhancement pattern was performed in the early vascular, late vascular, and parenchymal phases. Results: In the early vascular phase, a hypoechoic pattern was significantly associated with malignancy (P = .02) with sensitivity of 38% (95% confidence interval [CI], 25-38%) and specificity of 100% (95% CI, 84-100%). In the late vascular phase, a hypoechoic pattern was significantly associated with malignancy (P = .001) with sensitivity of 81% (95% CI, 66-90%) and specificity of 85% (95% CI, 65-95%). There was no significant difference between malignant and benign lesions during the parenchymal phase. Conclusions and Clinical Importance: Hypoechoic splenic nodules in the early and late vascular phases with perflubutane microbubbles-enhanced ultrasonography are strongly suggestive of malignancy in dogs.
  • Shiang-Jyi Hwang, Masahiro Yamasaki, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Bandula Kumara, Wickramasekara Rajapakshage, Hiroshi Ohta, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    The Japanese journal of veterinary research 58 3-4 155 - 64 2010年11月 [査読有り][通常論文]
     
    In our previous report, we developed a diminazene aceturate (DA)-resistant Babesia gibsoni strain that was maintained in culture with 200 ng/ml DA. While developing this strain, we also obtained DA-resistant B. gibsoni variants, which were maintained in culture with DA from 1 to 175 ng/ml for more than 8 weeks. Because heat shock protein 70 (Hsp70) seems to play important roles in adaptation to a stress environment in protozoan parasites, in the present study, we examined the copy number of B. gibsoni Hsp70 (BgHsp70) transcripts of those DA-resistant variants using quantitative real-time reverse transcription-polymerase chain reaction. We found that when wild-type B. gibsoni was exposed to 1 ng/ml DA, the level of BgHsp70 transcripts was decreased at day 14. The copy number of BgHsp70 transcripts in the DA-resistant variant cultured with 1 ng/ml DA was significantly lower than in wild-type B. gibsoni, while those in DA-resistant variants increased with escalating doses of DA from 1 to 75 ng/ml, although they were lower than in wild-type B. gibsoni. However, those in DA-resistant variants cultured with >125 ng/ml DA were almost the same as wild-type B. gibsoni. These results indicated that the transcript levels of the BgHsp70 gene might be reduced when the parasites are exposed to a low concentration of DA, and then might recover to the normal level after achieving resistance against DA. We expect that further study of the function of BgHsp70 will elucidate the mechanism of drug resistance against DA in B. gibsoni.
  • Shiang-Jyi Hwang, Masahiro Yamasaki, Kensuke Nakamura, Noboru Sasaki, Masahiro Murakami, Bandula Kumara Wickramasekara Rajapakshage, Hiroshi Ohta, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 72 6 765 - 71 2010年06月 [査読有り][通常論文]
     
    We attempted to develop a strain of Babesia gibsoni resistant to diminazene aceturate (DA), an anti-babesial drug, in vitro. Since the DA-sensitive B. gibsoni strain could survive and proliferate in culture medium containing 1 ng/m l DA, the concentration of DA was gradually increased from 1 to 200 ng/ml. The results showed that the parasites could survive and proliferate in the medium containing 200 ng/m l DA, which was much higher than the 50% inhibitory concentration (IC(50)) of DA for B. gibsoni. Subsequently, these parasites were removed from erythrocytes and exposed directly to 200 ng/ml DA. They were able to survive and invade fresh erythrocytes, though the DA-sensitive B. gibsoni strain did not survive. Based on these results, the parasites cultured within 200 ng/ml DA were determined to be a DA-resistant B. gibsoni strain. In addition, the IC(50) levels of clindamycin, doxycycline and pentamidine for the DA-resistant B. gibsoni strain were determined. The IC(50) levels of clindamycin, doxycycline and pentamidine for the DA-resistant strain were higher than those for the DA-sensitive strain. The IC(50) of pentamidine for the resistant strain was much greater than that for the DA-sensitive strain. These results indicated that the DA-resistant B. gibsoni strain could have resistance not only to DA, but also to other anti-babesial drugs. In conclusion, we successfully developed a DA-resistant B. gibsoni strain in vitro.
  • Kensuke Nakamura, Satoshi Takagi, Noboru Sasaki, Wickramasekara Rajapakshage Bandula Kumara, Masahiro Murakami, Hiroshi Ohta, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY RADIOLOGY & ULTRASOUND 51 1 79 - 85 2010年01月 [査読有り][通常論文]
     
    In six normal beagles and 27 dogs with spontaneous focal or multifocal liver lesions, contrast-enhanced ultrasonography using Sonazoid (R) was performed. Sonazoid (R) is a newly developed second-generation contrast agent with the ability to be used for real-time contrast imaging along with parenchymal imaging. An appropriate protocol for the evaluation of all three phases (arterial, portal, and parenchymal) was established based on the results for normal beagles. By evaluation of the echogenicity of hepatic nodules during the arterial and parenchymal phases it was possible to differentiate malignant tumors from benign nodules with very high accuracy. In 15 of 16 dogs diagnosed as malignant tumors, nodules were clearly hypoechoic to the surrounding normal liver during the parenchymal phase. Additionally, malignant tumors had different echogenicity compared with the surrounding normal liver during the arterial phase in 14 of 15 dogs. In the portal phase, there were no characteristic findings. Contrast-enhanced ultrasonography with Sonazoid (R) appears to improve the characterization of canine focal and multifocal hepatic lesions.
  • Masahiro Yamasaki, Kensuke Nakamura, Norihisa Tamura, Shiang-Jyi Hwang, Muneyoshi Yoshikawa, Noboru Sasaki, Hiroshi Ohta, Osamu Yamato, Yoshimitsu Maede, Mitsuyoshi Takiguchi
    The Journal of parasitology 95 6 1532 - 8 2009年12月 [査読有り][通常論文]
     
    Valinomycin and salinomycin-Na, 2 ionophorous antibiotics, exhibited in vitro antibabesial activities against Babesia gibsoni that infected normal canine erythrocytes containing low potassium (LK) and high sodium concentrations, i.e., LK erythrocytes, which completely lack Na,K-ATPase activity. The level of parasitemia of B. gibsoni was significantly decreased when the parasites were incubated in culture medium containing either 10(-1) ng/ml valinomycin or 10(2) ng/ml salinomycin-Na for 24 hr. Four-hour incubation in the culture medium containing 5 μg/ml salinomycin-Na led to the destruction of most parasites. In contrast, when the parasites infected canine erythrocytes containing high potassium (HK) and low sodium concentrations, i.e., HK erythrocytes, the in vitro antibabesial activities of both ionophorous antibiotics seemed to be weakened, apparently due to the protection by the host cells. Therefore, differential influences of ionophorous antibiotics on LK and HK erythrocytes were observed. In LK erythrocytes, the intracellular concentrations of potassium, sodium, and adenosine triphosphate (ATP) were not modified, and hemolysis was not observed after incubation in the medium containing each ionophorous antibiotic. These results suggested that these ionophorous antibiotics did not affect cells without Na,K-ATPase, and directly affected B. gibsoni. In HK erythrocytes, the ionophorous antibiotics increased the intracellular sodium concentration, and decreased the intracellular potassium and ATP concentrations, causing obvious hemolysis. Additionally, the decrease of the intracellular ATP concentration and the hemolysis in HK erythrocytes caused by valinomycin disappeared when the activity of Na,K-ATPase was inhibited by ouabain. These results indicate that modification of the intracellular cation concentrations by the ionophorous antibiotics led to the activation of Na,K-ATPase and increased consumption of intracellular ATP, and that the depletion of intracellular ATP resulted in hemolysis in HK erythrocytes. Moreover, the antibabesial activity of valinomycin disappeared when B. gibsoni in LK erythrocytes were incubated in culture media containing high potassium concentrations. This showed that the intracellular cation concentration in the parasites was not modified in those media and would remain the same.
  • Hiroshi OHTA, Satoshi TAKAGI, Masahiro MURAKAMI, Noboru SASAKI, Muneyoshi YOSHIKAWA, Kensuke NAKAMURA, Shiang-Jyi HWANG, Masahiro YAMASAKI, Mitsuyoshi TAKIGUCHI
    The Journal of veterinary medical science 71 11 1533 - 5 2009年11月 [査読有り][通常論文]
     
    A 7-year-old female Boston terrier was referred to Hokkaido University Veterinary Teaching Hospital with a history of hemoglobinuria and anemia for several days. Abdominal radiographs showed splenomegaly, and ultrasonography revealed a hypoechoic splenic parenchyma with interspersed linear echoes consistent with the ultrasonographic appearance of splenic torsion. Ultrasonography and computed tomography (CT) indicated a C-shaped spleen. Exploratory laparotomy confirmed the diagnosis of splenic torsion. A splenectomy was performed, and the dog recovered well without complications. This is the first report of splenic torsion in Boston terriers, and the usefulness of ultrasonographic and CT findings of the splenic torsion was also confirmed.
  • Kensuke Nakamura, Noboru Sasaki, Muneyoshi Yoshikawa, Hiroshi Ohta, Shiang-Jyi Hwang, Takahiro Mimura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY RADIOLOGY & ULTRASOUND 50 1 104 - 108 2009年01月 [査読有り][通常論文]
     
    Contrast-enhanced ultrasonography has an important role in the detection of tumors in humans. The second-generation contrast agent Sonazoid has the ability of real-time contrast imaging along with parenchymal imaging. The purposes of this study were to determine the effect and duration of Sonazoid on the changes in gray-scale enhancement of canine spleen and to establish an appropriate protocol for contrast-enhanced ultrasonography of canine spleen. Six healthy beagles were injected with an intravenous bolus of Sonazoid. In the spleen parenchyma, the enhancement was maintained up to 30 min after injection. Moreover, for 5-22 s after injection, gray-scale enhancement of splenic arteries afforded arterial imaging. Perfusion of the kidney may be investigated from 3.6 s to 3.5 min after injection of Sonazoid. These results suggest that Sonazoid is applicable to canine spleen parenchymal imaging and that the optimal time for the parenchymal imaging is 7-30 min after injection. The findings of this quantitative study should prove useful in the evaluation of diffuse or focal splenic and renal diseases in dogs.

書籍

  • 犬と猫の治療ガイド2015 私はこうしている
    中村健介 (担当:共著範囲:第2章 循環器疾患 猫の肥大型心筋症)
    インターズー 2015年09月
  • 猫の心臓病 臨床とエビデンスにもとづく診断と治療
    中村健介 (担当:共訳範囲:SECTION B 診断検査)
    インターズー 2015年07月
  • 犬と猫の超音波診断マニュアル
    中村健介 (担当:共訳範囲:第5章 胸部、第6章 心臓、第8章 肝臓、第9章 脾臓)
    学窓社 2013年10月

講演・口頭発表等

その他活動・業績

特許

  • 特願PCT/JP2013/004697:医用データ処理装置、医用データ処理方法、及び超音波診断装置  
    高木一也, 滝口満喜, 中村健介

受賞

  • 2012年09月 平成24年度日本小動物獣医学会地区学会長賞
     
    受賞者: 中村健介
  • 2011年09月 平成23年度日本小動物獣医学会北海道獣医師会長賞
     
    受賞者: 中村健介
  • 2011年03月 第151回日本獣医学会学術集会大会長賞
     
    受賞者: 中村健介
  • 2010年09月 平成22年度日本小動物獣医学会地区学会長賞
     
    受賞者: 中村健介
  • 2009年09月 平成21年度日本小動物獣医学会地区学会長賞
     
    受賞者: 中村健介
  • 2007年09月 平成19年度日本小動物獣医学会地区学会長賞
     
    受賞者: 中村健介

共同研究・競争的資金等の研究課題

  • 肺内短絡血管は肺塞栓症の重症化に関与しているか
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 中村 健介
  • 肺内短絡血管は肺塞栓症の重症化に関与しているか
    文部科学省:科学研究費補助金(基板研究(C))
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 中村健介
  • 右心機能に心エコーがどこまで迫れるのか?-肺高血圧症モデルを用いた検討-
    日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2016年04月 -2020年03月 
    代表者 : 中村 健介
     
    本年度は当初予定していた慢性肺塞栓モデルによる検討を行うことが研究スタッフ数の不足により困難であったため、肺高血圧症の犬の臨床例を対象とした臨床研究を行った。健常対照群(54頭)と肺高血圧症例群(21頭)を組み入れ、両群間における心エコー検査による右室機能指標(右室断面積変化率、三尖弁付着部移動距離、右室ストレイン)を比較した。肺高血圧症例群において右室は遠心性および求心性肥大しており、右室機能は低下していた。特に右室ストレインにより評価することができる右室の同期性は症例群で著しく障害されており、肺高血圧症患者では右室の効率的な運動が障害されいていることが明らかとなった。この右室同期障害を有していた症例では、より三尖弁逆流速度が速く、右室遠心性肥大が顕著で 、右室機能の低下も顕著であり、肺高血圧症の重症度が増すにつれて顕在化してくる現象であると考えられた。これらの結果は人の肺高血圧症患者におけるものと一致していた。肺高血圧症患者ではより重度の同期障害を有する場合、予後が不良であることも明らかになっており、犬においても同様に予後不良である可能性がある。また右室同期障害の発生には肺動脈圧上昇、右室遠心性肥大(拡張)が関与していると考えられた。これらをより詳細に解析するため例数を増やした検討や前向き研究が必要であり、今後解決すべき課題も多いが、本研究により臨床的に有用な知見が得られたと思われる。
  • 文部科学省:科学研究費補助金(若手研究(B))
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 中村健介
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 滝口 満喜, 中村 健介, 佐々木 東, 工藤 信樹
     
    超音波による診断と治療の融合の確立に向けた基盤を形成し、臨床応用へと発展させることを目的とし、犬の甲状腺癌および膀胱癌に対する超音波とマイクロバブルを用いた実用的な新規がん治療法「ソノポレーション」に関する前臨床段階の知見を得た。また、ソノポレーションの新たなメカニズムを明らかにすることで、臨床応用の基盤を構築した。
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2013年04月 -2017年03月 
    代表者 : 中村 健介, 大菅 辰幸
     
    本研究では、犬の左心房機能について、1.正常時に有する容量負荷への反応性、2.正常時に有する薬剤への反応性、3.疾患時における変化、について評価した。その結果、左心房は負荷や薬剤の影響によってその機能が通常の倍以上に変化する程の潜在能力を秘めている事が明らかとなった。疾患時にはこの潜在能力を発揮することで初期にはその機能が上昇するものの、より重度になるにつれ徐々に機能は減弱し、一定の限界を超えると死に至ることが明らかとなった。このように、左心房は疾患時にその力を発揮する「最後の砦」とも言える働きを有しているのかもしれない。
  • 新たな心エコー図検査スペックルトラッキング法による心房機能解析 〜負荷に対して心房は如何に反応するのか〜
    栗林育英学術財団:研究助成(個人研究の部)
    研究期間 : 2012年04月 -2013年03月 
    代表者 : 中村健介
  • 心房機能解析は心不全発症を予測する新規検査法となり得るか
    北海道大学:平成24年度総長室事業推進経費(公募型プロジェクト研究等支援経費)「若手研究者自立支援」
    研究期間 : 2012年04月 -2013年03月 
    代表者 : 中村健介
  • 肝臓腫瘤診断における造影超音波検査の応用に関する研究ー診断から分化度の評価へー
    日本学術振興会:特別研究員奨励費
    研究期間 : 2010年04月 -2012年03月 
    代表者 : 中村健介
  • 肝臓腫瘤診断における造影超音波検査の応用に関する研究―診断から分化度の評価へ―
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2010年 -2011年 
    代表者 : 中村 健介
     
    本研究では、ソナゾイド造影超音波検査による犬の肝臓腫瘤診断法を確立するとともに、特に肝細胞癌の分化度を評価する方法を確立するべく研究を行った。研究期間中に、対象となった肝臓腫瘤症例は67症例であり、11例が良性の結節性過形成、56例が悪性腫瘍であった。悪性腫瘍のうち、肝細胞癌が33例と最も多く、次いで血管肉腫4例、肝カルチノイド4例、胆管癌3例、組織球肉腫3例、その他9例であった。動脈相においては、良性腫瘤の多くがIsoに分類された(9/11,81.8%)のに対して、悪性腫瘍の多くがHyper(25/56,44.6%)もしくはHypo(18/56,32.1%)に分類された。Hyperと分類された症例の多くは癌腫であった(22/25,88.0%)。門脈相においては良性腫瘤の全例がIsoに分類された(11/11,100%)のに対して、悪性腫瘍の多くがHypoに分類された(40/56,71.4%)。ただし、肝細胞癌に却いては、Hypoに分類される例は約半数にとどまり(18/33,54.5%)、造影増強される例も比較的多く認められた。実質相において、良性腫瘤の全例が周囲の正常実質と同程度に造影され、Isoに分類された(11/11,100%)のに対して、悪性腫瘍の多くが明瞭な造影欠損を示し、Hypoと分類された(51/56,91%)。ただし、肝細胞癌においては、実質相で造影増強を示しIsoに分類される例も存在した(3/33,9.1%)。以上の様に、本研究により犬の肝臓腫瘤診断においてソナゾイド造影超音波検査が非常に優れた精度を持つことが明らかとなった。肝細胞癌の33例中、実質相においてIsoとなった症例は3例と非常に少ない割合であったがこれらの症例においてはHypoに分類された症例よりも、免疫染色によりKupffer細胞数が多い傾向が認められた。しかしながら一方で、今回の研究対象となった33症例の全てが病理組織学的検査により高分化型肝細胞癌と分類され、分化度に応じた比較は不可能であった。ただし、その中でも肝細胞癌を再発した症例が複数存在しており、病理検査の限界も見て取れた。従って、今後これらの症例に対して追跡調査を行い、肝細胞癌の再発率や予後とKupffer細胞数ならびに造影超音波検査所見との間に存在する因果関係を明らかとしたい。

大学運営

委員歴

  • 2015年04月 - 現在   日本獣医循環器学会   評議員


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