研究者データベース

横山 望(ヨコヤマ ノゾム)
獣医学研究院 附属動物病院
特任助教

基本情報

所属

  • 獣医学研究院 附属動物病院

職名

  • 特任助教

学位

  • 博士(獣医学, 北海道大学)

論文上での記載著者名

  • Nozomu Yokoyama
  • 横山 望
  • N Yokoyama
  • Yokoyama N
  • Nozomu YOKOYAMA
  • NOZOMU YOKOYAMA

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

職歴

  • 2019年06月 - 現在 北海道大学大学院獣医学研究院 附属動物病院 特任助教
  • 2018年10月 - 2019年05月 東京大学大学院農学生命科学研究科 附属動物医療センター 特任助教
  • 2017年07月 - 2018年09月 東京大学大学院農学生命科学研究科 附属動物医療センター 特任研究員
  • 2017年04月 - 2017年06月 酪農学園大学 非常勤講師
  • 2016年10月 - 2017年03月 北海道大学大学院獣医学研究科 獣医内科学教室 研究員
  • 2012年04月 - 2012年09月 北海道大学大学院獣医学研究科 附属動物病院 臨床研修獣医師
  • 2009年04月 - 2012年03月 公益財団法人 動物臨床医学研究所 研究員

学歴

  • 2012年10月 - 2016年09月   北海道大学大学院   獣医学研究科   獣医内科学教室
  • 2003年04月 - 2009年03月   酪農学園大学   獣医学部   獣医学科

所属学協会

  • 日本獣医がん学会   動物臨床医学会   日本獣医学会   

研究活動情報

論文

  • Hiroshi Ohta, Yu Tamura, Nozomu Yokoyama, Noriyuki Nagata, Tatsuyuki Osuga, Noboru Sasaki, Yumiko Kagawa, Keitaro Morishita, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 2020年08月05日 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are speculated to be a breed-specific inflammatory bowel disease (IBD). Leucine-rich alpha-2 glycoprotein (LRG) has been identified as a novel biomarker of human IBD. The aim of this study was to examine LRG gene expression in the polypoid lesions of ICRPs. Polypoid lesion specimens were collected from 24 MDs with ICRPs. Nonpolypoid colonic mucosa was collected from 18 MDs with ICRPs and 10 controls. The gene expression of LRG, interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and IL-22 was examined. The expression of LRG gene was significantly increased in the polypoid lesions of ICRPs and correlated with that of the four cytokines. In conclusion, the LRG gene was expressed within the polypoid lesions of ICRPs and might be associated with local cytokine expression.
  • Noboru Sasaki, Noriyuki Nagata, Keitaro Morishita, Tatsuyuki Osuga, Kazuyoshi Sasaoka, Nozomu Yokoyama, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 82 7 1012 - 1016 2020年07月31日 [査読有り][通常論文]
     
    The feasibility of ultrasonographic measurement of thyroid gland area to common carotid artery (TG:CCA) was investigated. Twenty-one healthy, 12 hypothyroid and 18 non-thyroid illness (NTI) dogs were evaluated. The area of thyroid lobe and common carotid artery in right and left sides were measured using the same ultrasonographic images in transverse plane. The average of the right and left ratio was calculated as TG:CCA. The median TG:CCA of 21 healthy dogs was 1.53, and it did not correlate either body weight or age. The median TG:CCA of 12 hypothyroid dogs was 0.81, which was significantly lower than that of 18 NTI dogs (1.81, P<0.001). If the cut off value <1.12 was used, TG:CCA indicated hypothyroidism with a sensitivity of 100%, specificity of 83%, and accuracy of 90%. Our data indicated that TG:CCA was independent of both body weight, which may contribute to consistent measurement of thyroid size. The results of this study suggest that TG:CCA is a promising tool for diagnosing canine hypothyroidism.
  • Kraisiri Khidkhan, Hazuki Mizukawa, Yoshinori Ikenaka, Shouta M M Nakayama, Kei Nomiyama, Nozomu Yokoyama, Osamu Ichii, Mitsuyoshi Takiguchi, Shinsuke Tanabe, Mayumi Ishizuka
    The Journal of veterinary medical science 82 7 978 - 982 2020年07月31日 [査読有り][通常論文]
     
    The knowledge of cytochrome P450 (CYP) expression involved in chemical exposure are necessary in clinical applications for the medication and prediction of adverse effects. The aim of this study was to evaluate the mRNA expression of CYP1-CYP3 families in cats exposed to BDE-209 for one year. All selected CYP isoforms showed no significant difference in mRNA expressions between control and exposure groups, however, CYP3A12 and CYP3A131 revealed tend to be two times higher in the exposure group compared to control group. The present results indicate that the chronic exposure of BDE209 could not alter CYP expression in the liver of cats. This result considered caused by the deficiency of CYP2B subfamily which is major metabolism enzyme of polybrominated diphenyl ethers (PBDEs) in cat.
  • Hiroshi Ohta, Jumpei Yamazaki, Jaroslav Jelinek, Teita Ishizaki, Yumiko Kagawa, Nozomu Yokoyama, Noriyuki Nagata, Noboru Sasaki, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 82 5 632 - 638 2020年05月20日 [査読有り][通常論文]
     
    DNA methylation is the covalent modification of methyl groups to DNA mostly at CpG dinucleotides and one of the most studied epigenetic mechanisms that leads to gene expression variability without affecting the DNA sequence. Genome-wide analysis of DNA methylation identified the signatures that could define subtypes of human lymphoma patients. The objective of this study was to conduct the genome-wide analysis of DNA methylation in dogs with gastrointestinal lymphoma (GIL). Genomic DNA was extracted from endoscopic biopsies from 10 dogs with GIL. We performed Digital Restriction Enzyme Assay of DNA Methylation (DREAM) for genome-wide DNA methylation analysis that could provide highly quantitative information on DNA methylation levels of CpG sites across the dog genome. We successfully obtained data of quantitative DNA methylation level for 148,601-162,364 CpG sites per GIL sample. Next, we analyzed 83,132 CpG sites to dissect the differences in DNA methylation between GIL and normal peripheral blood mononuclear cells (PBMCs). We found 383-3,054 CpG sites that were hypermethylated in GIL cases compared to PBMCs. Interestingly, 773 CpG sites including promoter regions of 61 genes were identified to be commonly hypermethylated in more than half of the cases, suggesting conserved DNA methylation patterns that are abnormal in GIL. This study revealed that there was a large number of hypermethylated sites that are common in most of canine GIL. These abnormal DNA methylation could be involved in tumorigenesis of the canine GIL.
  • Akiyoshi Tani, Taisuke Seno, Nozomu Yokoyama, Taisuke Nakagawa, Hirotaka Tomiyasu, Yuko Goto-Koshino, Hajime Tsujimoto, Koichi Ohno
    JOURNAL OF VETERINARY MEDICAL SCIENCE 82 4 437 - 440 2020年04月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) are frequently observed in miniature dachshunds in Japan and treated by prednisolone and immunosuppressive drugs such as cyclosporine and leflunomide. The purpose of this retrospective study was to compare the treatment efficacy, such as response rate, response interval, recurrence rate, and adverse events between cyclosporine and leflunomide. While the response rates were significantly higher in dogs treated with leflunomide, no significant differences were observed in the response interval or recurrence rate. Two of the 11 dogs treated with leflunomide showed hematological or gastrointestinal adverse events, while no dog treated with cyclosporine showed any adverse events. A case-controlled prospective study to compare the treatment efficacy of leflunomide with that of cyclosporine should be conducted.
  • Teita Ishizaki, Jumpei Yamazaki, Shinji Meagawa, Nozomu Yokoyama, Keisuke Aoshima, Mitsuyoshi Takiguchi, Takashi Kimura
    Veterinary and comparative oncology 2020年03月18日 [査読有り][通常論文]
     
    Canine malignant melanoma is a common cancer with a high mortality rate and is a clinically important disease. DNA methylation has been considered to be a potential tumorigenic mechanism through aberrant DNA methylation at promoter region which represses gene transcription. Global hypomethylation could also facilitate chromosome instability. There are few reports regarding DNA methylation in canine malignant melanoma; therefore, the purpose of this study was to examine DNA methylation status of long interspersed nucleotide element-1 (LINE-1) to be a surrogate marker of genome-wide methylation changes in this disease. We measured levels of DNA methylation of two adjacent cytosine-guanine sites on CpG island (CGI) at the putative promoter of canine LINE-1 sequence by bisulphite-pyrosequencing in 41 canine melanoma patient samples as well as six cell lines compared with normal mucosae. The survival rates were obtained from owners or medical records. We found DNA methylation levels of LINE-1 in normal mucosae were methylated. Interestingly, both melanoma cell lines and clinical melanoma samples showed remarkable hypomethylation. In addition, patients with lower LINE-1 methylation showed worse prognosis than those with higher LINE-1 methylation, though the difference did not reach statistical significance (P = .09). Here, we demonstrate that hypomethylation of LINE-1 is an epigenetically aberrant feature in canine melanoma with possible prognostic value.
  • Noriyuki Nagata, Hiroshi Ohta, Nozomu Yokoyama, Yong Bin Teoh, Khoirun Nisa, Noboru Sasaki, Tatsuyuki Osuga, Keitaro Morishita, Mitsuyoshi Takiguchi
    Journal of veterinary internal medicine 34 2 659 - 668 2020年03月 [査読有り][通常論文]
     
    BACKGROUND: In dogs with protein-losing enteropathy (PLE), data on the clinical characteristics of food-responsive PLE (FR-PLE) remain scarce. OBJECTIVE: To determine the clinical characteristics of FR-PLE in dogs responsive to ultralow-fat diet (ULFD) management. ANIMALS: Thirty-three dogs diagnosed with PLE based on standard diagnostic criteria. METHODS: Retrospective review of medical records. Clinical findings were compared between dogs with FR-PLE (FR-PLE group) and those with immunosuppressant-responsive PLE (IR-PLE) or nonresponsive PLE (NR-PLE) (IR/NR-PLE group). The area under the curve (AUC) of a receiver operating characteristic curve was used to evaluate the ability of factors to differentiate the FR-PLE and IR/NR-PLE groups. Survival time was compared between the FR-PLE and IR/NR-PLE groups. RESULTS: Twenty-three dogs responded to ULFD management and were diagnosed with FR-PLE. The canine chronic enteropathy clinical activity index (CCECAI) was significantly lower in the FR-PLE group than in the IR/NR-PLE group (P < .001). The AUC of CCECAI for differentiating the FR-PLE group was 0.935 (95% confidence interval [CI], 0.845-1.000) with an optimal cutoff value of 8 (sensitivity, 0.826; specificity, 0.889). Survival times were significantly longer in the FR-PLE group (median, not reached) than in the IR/NR-PLE group (median, 432 days; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs that respond to ULFD management and are diagnosed with FR-PLE are expected to have a favorable prognosis. Clinical scores, specifically the CCECAI, could be useful for differentiating FR-PLE from IR-PLE or NR-PLE.
  • Kraisiri Khidkhan, Hazuki Mizukawa, Yoshinori Ikenaka, Shouta M M Nakayama, Kei Nomiyama, Nozomu Yokoyama, Osamu Ichii, Wageh Sobhy Darwish, Mitsuyoshi Takiguchi, Shinsuke Tanabe, Mayumi Ishizuka
    Comparative biochemistry and physiology. Toxicology & pharmacology : CBP 226 108613 - 108613 2019年12月 [査読有り][通常論文]
     
    Cats have been known to be extremely sensitive to chemical exposures. To understand these model species' sensitivity to chemicals and their toxicities, the expression profiles of xenobiotic-metabolizing enzymes should be studied. Unfortunately, the characterization of cytochrome P450 (CYP), the dominant enzyme in phase I metabolism, in cats has not extensively been studied. Polychlorinated biphenyls (PCBs) are known as CYP inducers in animals, but the information regarding the PCB-induced CYP expression in cats is limited. Therefore, in the present study, we aimed to elucidate the mRNA expression of the CYP1-CYP3 families in the cat tissues and to investigate the CYP mRNA expression related to PCB exposure. In cats, the greatest abundance of CYP1-CYP3 (CYP1A2, CYP2A13, CYP2C41, CYP2D6, CYP2E1, CYP2E2, CYP2F2, CYP2F5, CYP2J2, CYP2U1, and CYP3A132) was expressed in the liver, but some extrahepatic isozymes were found in the kidney (CYP1A1), heart (CYP1B1), lung (CYP2B11 and CYP2S1) and small intestine (CYP3A131). In cats, CYP1A1, CYP1A2 and CYP1B1 were significantly upregulated in the liver as well as in several tissues exposed to PCBs, indicating that these CYPs were distinctly induced by PCBs. The strong correlations between 3,3',4,4'-tetrachlorobiphenyl (CB77) and CYP1A1 and CYP1B1 mRNA expressions were noted, demonstrating that CB77 could be a potent CYP1 inducer. In addition, these CYP isoforms could play an essential role in the PCBs biotransformation, particularly 3-4 Cl-PCBs, because a high hydroxylated metabolite level of 3-4 Cl-OH-PCBs was observed in the liver.
  • Hajime Asada, James K Chambers, Mari Kojima, Yuko Goto-Koshino, Taisuke Nakagawa, Nozomu Yokoyama, Masaya Tsuboi, Kazuyuki Uchida, Hajime Tsujimoto, Koichi Ohno
    Journal of feline medicine and surgery 1098612X19884763  2019年11月05日 [査読有り][通常論文]
     
    OBJECTIVES: Primary copper-associated hepatopathy (PCH) has been reported in young cats. Although our group recently reported a young cat with PCH harbouring single-nucleotide variations in ATP7B, limited information is available regarding its association with the pathogenesis of feline PCH. The objective of this study was to investigate the prevalence of ATP7B variations in cats with PCH. METHODS: Rhodanine staining was performed to detect hepatic copper accumulation (HCA) in intraoperative liver tissue specimens from 54 cats. In cats with HCA, variations in ATP7B and COMMD1 and serum ceruloplasmin activity were analysed. RESULTS: Based on age, liver histopathological findings and hepatic distribution of accumulated copper, PCH was suspected in 4/54 cats. Sequence analysis of ATP7B and COMMD1 revealed single-nucleotide variations in ATP7B in 3/4 cats with PCH. Among cats with PCH one showed remarkably low serum ceruloplasmin activity, while the other three did not. CONCLUSIONS AND RELEVANCE: The results of this study suggest that some cats with PCH harbour single-nucleotide variations in ATP7B, suggesting that feline PCH is an equivalent disorder to human Wilson's disease. This study provides basic evidence facilitating further studies of the pathophysiology and treatment of feline PCH.
  • Kohki Takaguchi, Hiroyuki Nishikawa, Hazuki Mizukawa, Rumi Tanoue, Nozomu Yokoyama, Osamu Ichii, Mitsuyoshi Takiguchi, Shouta M M Nakayama, Yoshinori Ikenaka, Tatsuya Kunisue, Mayumi Ishizuka, Shinsuke Tanabe, Hisato Iwata, Kei Nomiyama
    The Science of the total environment 688 1172 - 1183 2019年10月20日 [査読無し][通常論文]
     
    Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) might disrupt thyroid function. However, there is no clear evidence of PCB exposure disrupting thyroid hormone (TH) homeostasis in dogs and cats. The present study conducted in vivo experiments to evaluate the effects of a mixture of 12 PCB congeners (CB18, 28, 70, 77, 99, 101, 118, 138, 153, 180, 187 and 202, each congener 0.5 mg/kg BW, i.p. administration) on serum TH levels in male dogs (Canis lupus familiaris) and male cats (Felis silvestris catus). In PCB-exposed dogs, the time courses of higher-chlorinated PCBs and L-thyroxine (T4)-like OH-PCBs (4-OH-CB107 and 4-OH-CB202) concentrations were unchanged or tended to increase, whereas those of lower-chlorinated PCBs and OH-PCBs tended to decrease after 24 h. In PCB-exposed cats, concentrations of PCBs increased until 6 h and then remained unchanged. The levels of lower-chlorinated OH-PCBs including 4'-OH-CB18 increased until 96 h and then decreased. In PCB-exposed dogs, free T4 concentrations were higher than those in the control group at 48 and 96 h after PCB administration and positively correlated with the levels of T4-like OH-PCBs, suggesting competitive binding of T4 and T4-like OH-PCBs to a TH transporter, transthyretin. Serum levels of total T4 and total 3,3',5-triiodo-L-thyronine (T3) in PCB-exposed dogs were lower than in the control group at 24 and 48 h and negatively correlated with PCB concentrations, implying that PCB exposure enhanced TH excretion by increasing TH uptake and TH conjugation enzyme activities in the dog liver. In contrast, no obvious changes in TH levels were observed in PCB-exposed cats. This could be explained by the lower levels of T4-like OH-PCBs and lower hepatic conjugation enzyme activities in cats compared with dogs. Different effects on serum TH levels in PCB-exposed dogs and cats are likely to be attributable to species-specific PCB and TH metabolism.
  • Maho Nakazawa, Shingo Maeda, Nozomu Yokoyama, Taisuke Nakagawa, Tomohiro Yonezawa, Koichi Ohno, Naoaki Matsuki
    The Journal of veterinary medical science 81 9 1249 - 1258 2019年09月03日 [査読有り][通常論文]
     
    Inflammatory bowel disease (IBD) is a common gastrointestinal disease in dogs. Decreased production of intestinal immunoglobulin A (IgA) has been suggested as a possible pathogenesis in a subset of canine IBD; however, the underlying cause remains unclear. Sphingosine-1-phosphate (S1P) is a lipid mediator that regulates intestinal IgA production by controlling lymphocyte trafficking in mice. The objectives of this study were to clarify the role of S1P in IgA production in dogs and to evaluate the expression of S1P-related molecules in dogs with IBD. First, an S1P receptor antagonist was administrated to five healthy dogs. The S1P receptor antagonist significantly decreased the IgA concentration in sera and feces but did not affect the IgG concentration. Moreover, the immunoreactivity of intestinal IgA was significantly decreased by S1P signal blockade. These results indicate that S1P signaling specifically regulates the intestinal IgA production in dogs. Subsequently, the intestinal S1P concentration and the expression of S1P-related molecules were measured in dogs with IBD and healthy dogs. The intestinal concentration of S1P was significantly lower in dogs with IBD than in healthy dogs. In addition, the gene expression levels of S1P receptor (S1P1) and S1P synthase (SK1) were significantly lower in dogs with IBD than in healthy dogs. Taken together, these observations suggest that decreased S1P production, likely caused by a lower expression of S1P synthetase, leads to attenuation of S1P/S1P1 signaling pathway and the production of intestinal IgA in dogs with IBD.
  • 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.
  • Y Ohara, A Yabuki, R Nakamura, O Ichii, H Mizukawa, N Yokoyama, O Yamato
    Journal of comparative pathology 170 53 - 59 2019年07月 [査読無し][通常論文]
     
    During the progression of chronic kidney disease (CKD), macrophage infiltration is a crucial event leading to tubulointerstitial fibrosis. In the present study, macrophages infiltrating renal tissue in dogs and cats with CKD were analysed immunohistochemically. Iba-1 was used as a pan-macrophage marker, CD204 was used as a marker of M2 macrophages and tumour necrosis factor (TNF)-α was used as a marker of M1 macrophages. Signals for Iba1 and CD204 were observed in the interstitium of all tested kidney samples. In dogs, the signals were diffusely scattered. In cats, both diffuse and focal signals were observed. Cells that were positive for Iba1 and CD204 were also observed in the tubular lumina in cats. Co-expression of Iba1 and CD204 was also observed in the infiltrating cells by immunofluorescence labelling, and these cells were negative for TNF-α. By quantitative analysis, the indices for Iba1- and CD204-positive cells were significantly correlated with the concentrations of plasma creatinine and/or urea and the extent of interstitial fibrosis in both dogs and cats. These results demonstrated that renal infiltration of M2 macrophages plays an important role in the progression of CKD in dogs and cats. The distribution pattern of the kidney-infiltrating macrophages was unique in cats and may be associated with a cat-specific renal fibrotic process.
  • M Nakazawa, S Maeda, M Omori, K Kaji, N Yokoyama, T Nakagawa, J K Chambers, K Uchida, K Ohno, T Yonezawa, N Matsuki
    Veterinary journal (London, England : 1997) 249 47 - 52 2019年07月 [査読有り][通常論文]
     
    Although antimicrobial peptides (AMPs) play an integral role in the regulation of intestinal microbiota and homeostasis, their expression in canine gastrointestinal diseases, including idiopathic inflammatory bowel disease (IBD) and intestinal lymphoma, remains unknown. The objective of this study was to investigate the intestinal expression of AMPs in dogs with IBD or intestinal lymphoma. IBD was diagnosed in 44 dogs, small cell intestinal lymphoma in 25 dogs, and large cell intestinal lymphoma in 19 dogs. Twenty healthy beagles were used as normal controls. Duodenal mRNA expression of six representative AMPs - lactoferrin, lysozyme, cathelicidin, secretory leukocyte peptidase inhibitor (SLPI), bactericidal/permeability increasing protein (BPI), and canine beta defensin (CBD103) - was quantified by real-time reverse transcription polymerase chain reaction. The relative expression of BPI, lactoferrin, and SLPI was significantly higher in dogs with IBD and intestinal lymphomas than in healthy controls. Interestingly, the expression patterns of AMPs differed between dogs with IBD and those with intestinal lymphomas, especially small cell lymphoma. Increased expression of BPI differentiated IBD from dogs with small cell intestinal lymphoma, with a sensitivity of 93.2%, a specificity of 100%, and an area under the curve of 0.955. These results suggest that the expression patterns of AMP aid in the diagnosis of canine IBD and intestinal lymphoma, although it remains uncertain whether the altered AMP expression is the cause or effect of mucosal inflammation.
  • 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.
  • 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.
  • Hajime Asada, Mari Kojima, Takuro Nagahara, Yuko Goto-Koshino, James K Chambers, Taisuke Nakagawa, Nozomu Yokoyama, Kazuyuki Uchida, Hajime Tsujimoto, Koichi Ohno
    Journal of veterinary internal medicine 33 2 874 - 878 2019年03月 [査読有り][通常論文]
     
    A 9-month-old intact crossbred female cat was presented with jaundice, intermittent anorexia and lethargy, increased hepatic enzyme activities, and hyperammonemia. Abdominal ultrasound and computed tomographic examinations determined that the liver had a rounded and irregular margin, and histopathological examination identified excessive accumulation of copper hepatocytes in the liver. Concentrations of both blood and urine copper were higher than in healthy cats. The patient responded well to treatment with penicillamine. Clinicopathological abnormalities and clinical signs improved within 2 months, and the patient was alive for >9 months after starting treatment. Genetic examination determined that the patient and its littermate had a single-nucleotide variation (SNV, p. T1297R) that impaired the function of the ATP7B gene product; the gene that is mutated in patients with Wilson's disease (WD). Hepatic copper accumulation was believed to be associated with the SNV of the ATP7B gene, and the patient had a genetic disorder of copper metabolism equivalent to WD in humans.
  • Taisuke Nakagawa, Akihiro Doi, Koichi Ohno, Nozomu Yokoyama, Hajime Tsujimoto
    JOURNAL OF VETERINARY MEDICAL SCIENCE 81 3 348 - 352 2019年03月 [査読有り][通常論文]
     
    Megaesophagus (ME) is a common esophageal disease in dogs and the prognosis is generally poor, especially with aspiration pneumonia (AP). We retrospectively investigated the clinical features and prognosis of canine ME in Japan. Twenty-eight dogs were included in this study, with the Miniature Dachshund breed being significantly overrepresented (odds ratio: 4.33). Most cases (21 of 28) were diagnosed as idiopathic ME and Myasthenia gravis was the most common cause of secondary ME. The overall median survival time (MST) was not reached and the 3-month survival rate was 85.7%. Ten dogs were diagnosed with AP, at least once during the study period, and the MST of ME dogs with AP was 114 days. The survival time overall and even with AP, was notably more prolonged compared to the previous studies. We hypothesized that treatment for canine ME could prolong the survival time, even in those with both ME and AP.
  • Itsuma Nagao, Koichi Ohno, Takuro Nagahara, Nozomu Yokoyama, Taisuke Nakagawa, Reina Fujiwara, Kie Yamamoto, Yuko Goto-Koshino, Hirotaka Tomiyasu, Hajime Tsujimoto
    Journal of Veterinary Medical Science 81 11 1552 - 1557 2019年 [査読有り][通常論文]
     
    © 2019 The Japanese Society of Veterinary Science. In human medicine, computed tomography (CT) is the gold standard for visceral fat measurement. Research shows that the visceral fat area (VFA) of the umbilical slice is significantly correlated with the visceral fat volume (VFV). In veterinary medicine, however, few studies have evaluated visceral fat using CT. This study aimed to evaluate the visceral fat in dogs using CT images, and determine if the slice significantly correlated with VFV to simplify visceral fat measurements. This retrospective study includes data on 90 dogs that underwent whole-body CT scans for diagnostic purposes. VFV was calculated as the product of VFA and thickness in each CT slice; the correlation between VFV and VFA was analyzed at the level of each lumbar vertebra. Visceral fat percentage (VF%) was calculated as the ratio of the product of VFV and fat density to the body weight. Visceral fat area percentage (VFA%) was calculated as the ratio of VFA to the body area, and its correlation with the VF% and the body condition score (BCS) was analyzed. VFA was highly correlated with VFV at the level of each lumbar vertebra, with the highest correlation (r=0.964) at the L3 level. VFA% was significantly correlated with VF% (r=0.930) and weakly correlated with BCS (r=0.523). This study demonstrates that it is sufficient to use only the L3 slice for visceral fat evaluation and that the evaluation can be based on VFA% of the L3 level.
  • 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 mu g/L) in 5 dogs and as abnormal (>= 400 mu g/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 mu g/L) was observed in only 1 dog. No ultrasonographic or histological evidence of pancreatitis was observed in any of the dogs.
  • R. Nakamura, A. Yabuki, O. Ichii, H. Mizukawa, N. Yokoyama, O. Yamato
    Journal of Comparative Pathology 160 79 - 83 2018年04月01日 [査読有り][通常論文]
     
    Renal capillary rarefaction is a crucial event that leads to tubulointerstitial damage during the progression of chronic kidney disease (CKD). In the present study, changes in CD34-positive renal capillaries were investigated in dogs and cats with CKD. A significant decrease in CD34-positive capillaries was observed in canine diseased kidneys, even at the early stage of disease. In cats, CD34-positive capillaries were well preserved in the diseased kidneys, with no link to the severity of CKD. Renal capillary rarefaction might be a trigger event that leads to the progression of CKD in dogs, rather than 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.
  • Khoirun Nisa, Sue Yee Lim, Tatsuyuki Osuga, Nozomu Yokoyama, Masahiro Tamura, Noriyuki Nagata, Kazuyoshi Sasaoka, Angkhana Dermlim, Rommaneeya Leela-Arporn, Tomoya Morita, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    The Journal of veterinary medical science 80 3 453 - 459 2018年03月24日 [査読有り][通常論文]
     
    Quantitative contrast-enhanced ultrasonography (CEUS) enables non-invasive and objective evaluation of intestinal perfusion by quantifying the intensity of enhancement on the intestine after microbubble contrast administration. During CEUS scanning, sedation is sometimes necessary to maintain animal cooperation. Nevertheless, the effect of sedative administration on the canine intestinal CEUS is unknown. This study aimed to investigate the effect of sedation with a combination of butorphanol and midazolam on the duodenal CEUS-derived perfusion parameters of healthy dogs. For this purpose, duodenum was imaged following contrast administration (Sonazoid®, 0.01 ml/kg) in six healthy beagles before and after intravenous injection of a combination of butorphanol (0.2 mg/kg) and midazolam (0.1 mg/kg). Furthermore, hemodynamic parameters including blood pressure and heart rate were recorded during the procedure. Five CEUS derived perfusion parameters including time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), wash-in and wash-out rates (WiR and WoR, respectively) before and after sedation were statistically compared. The result showed that no significant change was detected in any of perfusion parameters. Systolic and mean arterial pressures significantly reduced after sedative administration, but diastolic arterial pressure and heart rate did not significantly change. Moreover, no significant partial correlation was observed between perfusion parameters and hemodynamic parameters. Thus, we concluded that the combination did not cause significant influence in duodenal CEUS perfusion parameters and could be a good option for sedation prior to duodenal CEUS in debilitated dogs.
  • K. Sasaoka, K. Nakamura, T. Osuga, T. Morita, N. Yokoyama, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    Journal of Veterinary Internal Medicine 32 1 314 - 323 2018年01月01日 [査読有り][通常論文]
     
    Background: Transcranial Doppler ultrasound examination (TCD) is a rapid, noninvasive technique used to evaluate cerebral blood flow and is useful for the detection of intracranial hypertension in humans. However, the clinical usefulness of TCD in diagnosing intracranial hypertension has not been demonstrated for intracranial diseases in dogs. Objectives: To determine the association between the TCD variables and intracranial hypertension in dogs with intracranial diseases. Animals: Fifty client-owned dogs with neurologic signs. Methods: Cross-sectional study. All dogs underwent TCD of the basilar artery under isoflurane anesthesia after magnetic resonance imaging (MRI). Dogs were classified into 3 groups based on MRI findings: no structural diseases (group I), structural disease without MRI evidence of intracranial hypertension (group II), and structural disease with MRI evidence of intracranial hypertension (group III). The TCD vascular resistance variables (resistive index [RI], pulsatility index [PI], and the ratio of systolic to diastolic mean velocity [Sm/Dm]) were measured. Results: Fifteen, 22, and 13 dogs were classified into groups I, II, and III, respectively. Dogs in group III had significantly higher Sm/Dm (median, 1.78 range, 1.44–2.58) than those in group I (median, 1.63 range, 1.43–1.75) and group II (median, 1.62 range, 1.27–2.10). No significant differences in RI and PI were identified among groups. Conclusions and Clinical Importance: Our findings suggest that increased Sm/Dm is associated with MRI findings of suspected intracranial hypertension in dogs with intracranial diseases and that TCD could be a useful tool to help to diagnose intracranial hypertension.
  • 高口 倖暉, 中山 翔太, 池中 良徳, 石塚 真由美, 岩田 久人, 国末 達也, 田辺 信介, 野見山 桂, 西川 博之, 水川 葉月, 田上 瑠美, 草木 桃子, 横山 望, 市居 修, 滝口 満喜
    日本毒性学会学術年会 45 0 P - 72 日本毒性学会 2018年 [査読有り][通常論文]
     

    近年、ペット動物に対するポリ塩化ビフェニル(PCBs)および水酸化代謝物(OH-PCBs)の曝露による甲状腺ホルモン(THs)の恒常性への影響が注目されている。本研究ではPCBs曝露がペット動物のTHs恒常性に及ぼす影響を明らかにするため、イヌ・ネコのPCBs投与試験を実施し、PCBs曝露に伴う血清中THs濃度の変化を解析した。

    PCBs投与後から5日間、継続的に血清を採取し、THs濃度の変化を解析した結果、ネコ血清中THs濃度は、総THs、遊離型THsともに対照群と投与群の間に有意な変化は認められなかった。一方、イヌ血清中総THs濃度は投与群において、総L-サイロキシン(T4)と総3,5,3'-トリヨード-L-サイロニン(T3)の減少傾向がみられ、総PCBs濃度は総T4、総T3濃度と有意な負の相関を示した(p < 0.01)。一方、遊離型T4、遊離型T3濃度では、対照群と投与群の間に経時的な変化は認められなかったが、曝露後48、96時間目で有意に増加した(p < 0.05)。加えて、遊離型T4濃度は総OH-PCBs濃度と正の相関を示し(p < 0.01)、異性体別ではT4様構造の高塩素化OH-PCBsで同様の傾向が認められた。上記の結果および先行研究から、PCBs曝露によるイヌ血清中THsへの影響を推察した。PCBsがT4様構造のOH-PCBsへ代謝されてTHs輸送タンパクに競合結合し、結合できない遊離型T4が血中に増加することで、THsの臓器・組織への取り込み量が増加したと予測される。その結果、イヌ肝臓中のTHs濃度は増加し、PCBs曝露により肝臓中のAhR・CARが過剰に誘導されることで、UGTおよびSULTが誘導され、THsの抱合化を促進することで体外排泄量が増加し、血清中総T4、T3が減少したものと推察された。

  • ポリ塩化ビフェニル(PCBs)がネコの甲状腺機能に及ぼす影響
    水川 葉月, 高居 名菜, 野見山 桂, 高口 倖暉, 横山 望, 市居 修, 滝口 満喜, 池中 良徳, 中山 翔太, 石塚 真由美
    環境ホルモン学会研究発表会要旨集 20回 78 - 78 環境ホルモン学会(日本内分泌撹乱化学物質学会) 2017年12月 [査読有り][通常論文]
  • 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.
  • 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
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 9 1585 - 1590 2017年09月 [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 (R)) was administered using the intravenous bolus method (0.01 ml/kg) for imaging of the duodenum. Time-intensity curves (TIC) were created by drawing multiple regions of interest (ROIs) in the duodenal mucosa, and perfusion parameters, including the time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), and wash-in and wash-out rates (WiR and WoR, respectively), were generated. Intraday and interday coefficients of variation (CVs) for TTP, PI, AUC, WiR and WoR were < 25% (range, 2.27-23.41%), which indicated that CEUS was feasible for assessing duodenal perfusion in healthy sedated dogs. A further study of CEUS in dogs with chronic intestinal disorders is necessary to evaluate its clinical applicability.
  • T. Morita, K. Nakamura, T. Osuga, N. Yokoyama, N. Khoirun, K. Morishita, N. Sasaki, H. Ohta, M. Takiguchi
    JOURNAL OF VETERINARY CARDIOLOGY 19 4 351 - 362 2017年08月 [査読有り][通常論文]
     
    Introduction: To assess the repeatability and characteristics of echocarCanine; diographic indices of the right ventricular (RV) function derived from speckle-track Cardiac; ing echocardiography. Right ventricular Animals: Fourteen laboratory Beagles and 103 privately owned dogs without cardifunction; ac disease were involved in this study. Dyssynchrony; Materials and methods: Right ventricular longitudinal strain, strain rate, and a Tei index strain-related index for assessing RV dyssynchrony derived from speckle-tracking echocardiography were obtained by two different observers using five Beagles. Within-day, between-day, and interobserver coefficients of variation and the intraclass correlation coefficient of speckle-tracking echocardiography indices were determined. Both speckle-tracking echocardiography and conventional indices of RV function, including the peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, and the Tel index, were obtained from 14 Beagles and 103 privately owned dogs. Relationships between echocardiographic indices and the body weight, heart rate, age, and sex were estimated by regression analysis. Results: Speckle-tracking echocardiographic indices showed good within-day repeatability, between-day and interobserver repeatability were moderate to good. In large dogs, RV longitudinal strain, strain rate, and fractional area change were significantly decreased, while the index of RV dyssynchrony, systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, and the Tei index were increased. All speckle-tracking and conventional echocardiographic indices were correlated with the body weight. Discussion and conclusions: The speckle-tracking echocardiography indices were highly repeatable and body weight affected speckle-tracking echocardiography indices in dogs. Further studies are needed to apply speckle-tracking echocardiography indices in dogs with cardiac disease. (C) 2017 Elsevier B.V. All rights reserved.
  • 犬と猫の慢性腎臓病における腎臓へのマクロファージ浸潤
    大原 優美子, 矢吹 映, 市居 修, 水川 葉月, 横山 望, 中村 麗菜
    日本獣医学会学術集会講演要旨集 160回 473 - 473 (公社)日本獣医学会 2017年08月 [査読有り][通常論文]
  • Tomoya Morita, Kensuke Nakamura, Tatsuyuki Osuga, Nozomu Yokoyama, Keitaro Morishita, Noboru Sasaki, Hiroshi Ohta, Mitsuyoshi Takiguchi
    ECHOCARDIOGRAPHY-A JOURNAL OF CARDIOVASCULAR ULTRASOUND AND ALLIED TECHNIQUES 34 7 1040 - 1049 2017年07月 [査読有り][通常論文]
     
    Background: The assessment of hemodynamic change by echocardiography is clinically useful in patients with pulmonary hypertension. Recently, mild elevation of the mean pulmonary arterial pressure (PAP) has been shown to be associated with increased mortality. However, changes in the echocardiographic indices of right ventricular (RV) function are still unknown. The objective of this study was to validate the relationship between echocardiographic indices of RV function and right heart catheterization variables under a mild RV pressure overload condition. Methods and Results: Echocardiography and right heart catheterization were performed in dog models of mild RV pressure overload induced by thromboxane A(2) analog (U46619) (n=7). The mean PAP was mildly increased (19.3 +/- 1.1mm Hg), and the cardiac index was decreased. Most echocardiographic indices of RV function were significantly impaired even under a mild RV pressure overload condition. Multivariate analysis revealed that the RV free wall longitudinal strain (RVLS), standard deviation of the time-to-peak longitudinal strain of RV six segments (RV-SD) by speckle-tracking echocardiography, and Tei index were independent echocardiographic predictors of the mean PAP (free wall RVLS, beta=-0.60, P<.001; RV-SD, beta=0.40, P=.011), pulmonary vascular resistance (free wall RVLS, beta=-0.39, P=.020; RV-SD, beta=0.47, P=.0086; Tei index, beta=0.34, P=.047), and cardiac index (Tei index, beta=-0.65, P<.001). Conclusions: Free wall RVLS, RV-SD, and Tei index are useful for assessing the hemodynamic change under a mild RV pressure overload condition.
  • H. Ohta, T. Morita, N. Yokoyama, T. Osuga, N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi
    JOURNAL OF SMALL ANIMAL PRACTICE 58 6 342 - 347 2017年06月 [査読有り][通常論文]
     
    ObjectivesIn this pilot study, serum canine pancreatic lipase immunoreactivity was measured repeatedly in dogs with various immune-mediated diseases that were treated with immunosuppressive doses of prednisolone. MethodsTen client-owned dogs with newly diagnosed immune-mediated disease that had normal canine pancreatic lipase immunoreactivity concentrations (200 mu g/l) were treated with 2 to 2.2 mg/kg prednisolone orally once daily as the initial treatment. Serum samples were obtained from each of the dogs prior to treatment and at 1- to 4-week intervals during immunosuppressive treatment. The highest canine pancreatic lipase immunoreactivity concentration detected during immunosuppressive treatment was defined as the peak canine pancreatic lipase immunoreactivity. ResultsPeak canine pancreatic lipase immunoreactivity concentrations were classified as normal in two dogs, questionable (201 to 399 mu g/l) in three dogs, and abnormal (400 mu g/l) in five dogs. Peak canine pancreatic lipase immunoreactivity concentrations were significantly higher than baseline canine pancreatic lipase immunoreactivity concentrations but there was no evidence of clinical pancreatitis. Clinical SignificanceIt remains unclear whether the five of 10 dogs with elevated canine pancreatic lipase immunoreactivity during prednisone treatment had subclinical pancreatitis or whether the abnormal results were a consequence of prednisolone administration.
  • Nozomu Yokoyama, Hiroshi Ohta, Yumiko Kagawa, Noriyuki Nagata, Khoirun Nisa, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Mitsuyoshi Takiguchi
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 188 78 - 83 2017年06月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are a possible novel form of breed-specific canine inflammatory bowel disease (IBD). In this pilot study, we investigated the effects of different Toll like receptor (TLR2, TLR4, TLR5 and TLR9) ligands on pro-inflammatory cytokines (IL-1 beta, IL-6, IL-8 and TNF-alpha) gene expression in ex vivo-cultured colorectal samples from four MDs with ICRPs and four healthy MDs. At baseline, no significant difference in the mRNA expression levels of TLRs and pro-inflammatory cytokines was observed between cases and control MDs. After 4-h incubation, the relative ratios of TNF-alpha mRNA expression in the TLR2-or TLR4-stimulated colorectal samples, and IL-1 beta mRNA expression in the TLR9-stimulated colorectal samples form cases showed higher tendency compared with healthy MDs (P < 0.05), although statistically not significant. The results of this pilot study using small number of cases indicated that reactivity against TLR2, TLR4 or TLR9 ligand in the production of pro-inflammatory cytokines might be enhanced in the colorectal mucosa of ICRPs. Further research is needed to perform the functional analysis of TLRs in the sole cell population using intestinal epithelial primary culture and the mononuclear cells isolated from colonic mucosa.
  • Nozomu Yokoyama, Hiroshi Ohta, Yumiko Kagawa, Rommaneeya Leela-Arporn, Angkhana Dermlim, Khoirun Nisa, Tomoya Morita, Tatsuyuki Osuga, Noboru Sasaki, Keitaro Morishita, Kensuke Nakamura, Mitsuyoshi Takiguchii
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 3 456 - 463 2017年03月 [査読有り][通常論文]
     
    We examine the expression of tight junction and adherence junction proteins in the colorectal mucosa of miniature dachshunds (MDs) with inflammatory colorectal polyps (ICRPs). Colorectal mucosa samples were endoscopically obtained from 8 MDs with ICRPs and 8 control dogs for immunoblotting. Paraffin-embedded tissues of surgically resected inflamed lesions from another 5 MDs with ICRPs and full-thickness colorectal specimens from 5 healthy beagles were obtained for immunohistochemistry. The expression patterns of claudin-1, -2, -3, -4, -5, -7 and -8, E-cadherin and beta-catenin were analyzed in the non(-)inflamed mucosa and inflamed mucosa of ICRPs and colorectal mucosa of control dogs by immunoblotting.The localization of these proteins in the inflamed lesions was analyzed by immunohistochemistry. The expressions of each of claudin, E-cadherin and beta-catenin were not significantly different between control dogs and non inflamed colonic mucosa from MDs with ICRPs. In contrast, only E-cadherin and beta-catenin were detected in the inflamed lesions of MDs with 1CRPs. By immunohistochemistry, claudin-2, -3, -4, -5 and -7, E-cadherin and beta-catenin were expressed in the colorectal epithelium within the inflamed mucosa, but not in granulation tissue. Distributions of claudin-2, -3, -4, -5, and -7, E-cadherin and beta-catenin in the colonic epithelium were not different between MDs with ICRPs and control dogs. These results indicated that no significant alteration was detected in several tight junction or adherence junction proteins expression in the colorectal epithelium of ICRPs.
  • N. Yokoyama, H. Ohta, J. Yamazaki, Y. Kagawa, O. Ichii, N. Khoirun, T. Morita, T. Osuga, S. Y. Lim, N. Sasaki, K. Morishita, K. Nakamura, M. Takiguchi
    JOURNAL OF COMPARATIVE PATHOLOGY 156 2-3 183 - 190 2017年02月 [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.
  • 水川 葉月, 中山 翔太, Tsend-ayush SAINNOXOI, 田辺 信介, 石塚 真由美, 高居 名菜, 横山 望, 市居 修, 滝口 満喜, 野見山 桂, 高口 倖暉, 西川 博之, 池中 良徳
    日本毒性学会学術年会 44 0 P - 55 日本毒性学会 2017年 [査読有り][通常論文]
     
    有機ハロゲン化合物の一種であるポリ塩化ビフェニル(PCBs)は甲状腺ホルモン(THs)の恒常性かく乱が懸念されており、実際、ヒトやげっ歯類においてはPCBs暴露により血中THs濃度の低下が認められている。ヒトの身近な動物であるネコは餌などを介してPCBsに暴露していると懸念され、THs恒常性に何らかの悪影響をもたらすことが予想される。本研究では、ネコの甲状腺機能に対するPCBsの影響を解析するため、in vivo投与試験したネコを用いて甲状腺機能への影響を解析した。血中のTHs濃度(総T4、総T3、遊離T4、遊離T3、リバースT3)を解析した結果、対照群と暴露群の間に有意な差は見られなかった。また、THsの恒常性に関与する遺伝子(甲状腺ホルモン受容体αおよびβ、脱ヨード酵素type1)の肝臓中発現量やTHs代謝に関わる酵素であるグルクロン酸抱合酵素(UGT1A1)の活性を調べたところ、対照群と暴露群の間に有意な差は見られなかった。
    本実験結果では、ネコにおいてPCBs短期暴露によるTHsへの影響が認められなかったが、日本のペットネコにおけるモニタリング調査では、血中のTHs濃度とPCBs濃度との間に負の相関が見られており、有機ハロゲン化合物によるTHsかく乱が懸念されている。また、本研究試料のメタボローム解析結果では酸化ストレスの発現、抗酸化物質、電子伝達物質の生産阻害などが示唆されており、PCBsや水酸化代謝物による内分泌撹乱作用が心配される。THsの恒常性は非常に複雑な機構のもと維持されていることが知られており、負のフィードバック機構に加え、THsの活性化や代謝、排泄の調整にも多くの遺伝子やトランスポーター、酵素など様々な要因が関わっていることから、ネコは長期的かつ慢性的に化学物質に暴露されることで、甲状腺機能などへの悪影響が現れると考えられ、内分泌撹乱作用の作用機序について解析を進めることが重要である。
  • Tatsuyuki Osuga, Kensuke Nakamura, Tomoya Morita, Khoirun Nisa, Nozomu Yokoyama, Noboru Sasaki, Keitaro Morishita, Hiroshi Ohta, Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH 77 9 952 - 960 2016年09月 [査読有り][通常論文]
     
    OBJECTIVE To elucidate the relationship between acute volume overload and left atrial phasic function in healthy dogs. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized. A Swan-Ganz catheter was placed to measure mean pulmonary capillary wedge pressure (PCWP). Cardiac preload was increased by IV infusion with lactated Ringer solution at 150 mL/kg/h for 90 minutes. Transthoracic echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after volume loading began. At each echocardiographic assessment point, apical 4-chamber images were recorded and analyzed to derive time-left atrial area curves. Left atrial total (for reservoir function), passive (for conduit function), and active (for booster-pump function) fractional area changes were calculated from the curves. RESULTS Volume overload resulted in a significant increase from baseline in PCWP from 15 to 90 minutes after volume loading began. All fractional area changes at 15 to 90 minutes were significantly increased from baseline. In multiple regression analysis, quadratic regression models were better fitted to the relationships between PCWP and each of the total and active fractional area changes than were linear regression models. A linear regression model was better fitted to the relationship between PCWP and passive fractional area change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that left atrial phasic function assessed on the basis of left atrial phasic areas was enhanced during experimental cardiac volume loading in healthy dogs. The effect of volume load should be considered when evaluating left atrial phasic function by indices derived from left atrial phasic sizes.
  • 犬と猫の慢性腎臓病における尿細管周囲毛細血管の変化
    中村 麗菜, 矢吹 映, 市居 修, 水川 葉月, 横山 望, 大和 修
    日本獣医学会学術集会講演要旨集 159回 462 - 462 (公社)日本獣医学会 2016年08月 [査読有り][通常論文]
  • 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 - 720 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.
  • 水川 葉月, 高口 倖暉, 田辺 信介, 石塚 真由美, 前原 美咲, 横山 望, 市居 修, 滝口 満喜, 野見山 桂, 西川 博之, 池中 良徳, 中山 翔太
    日本毒性学会学術年会 43 0 P - 6 日本毒性学会 2016年 [査読有り][通常論文]
     
    ポリ塩化ビフェニル(PCBs)の水酸化代謝物であるOH-PCBsは、肝臓内で薬物代謝酵素より生成され、その後体外へ排泄される。しかしながら、一部の水酸化代謝物は甲状腺ホルモン(TH)と類似の構造をもつため、THの恒常性を撹乱することが危惧されている。これまでに、多様な陸棲哺乳類の血中OH-PCBsを分析したところ、種間でOH-PCBsの組成に差異が認められ、中でも、ネコのOH-PCBs残留パターンは他種と大きく異なることから、本種は特異な代謝機能を有することが示唆された。しかし、ネコの異物代謝能の研究は僅かであり、化学物質暴露による毒性影響も不明な点が多い。本研究では、ネコにおけるPCBs in vivo暴露試験を実施し、体内動態および代謝に関与する酵素活性や遺伝子を解析するとともに、化学物質の暴露評価に繋がる基盤的情報の収集を目的とした。
    コーン油に溶解した12異性体のPCBsを腹腔内投与し、経時採血した血清中PCBsおよびOH-PCBs濃度について同条件で実施したイヌのin vivo試験と比較した結果、異性体の残留パターンや体内動態にイヌとネコで種差が観察された。とくにネコでは低塩素化体の残留が顕著であった。また、代謝酵素活性および遺伝子解析の結果、PCBs暴露によりEROD、MROD、PROD活性は上昇するものの、第2相抱合酵素(UGTやSULT)活性は変化せず、PCBs暴露による抱合酵素活性への影響もみられなかった。また、CYP1A1およびCYP1A2遺伝子の発現量の上昇も認められた。
    本研究により、ネコのPCBs吸収・代謝・排泄能はイヌと異なることが示唆され、とくに低塩素化OH-PCBsの毒性リスクは高いことが予想された。低塩素化OH-PCBsは血中でTH輸送タンパクとの競合結合や、THの硫酸抱合排泄の阻害、TH起因性遺伝子の転写抑制などが報告されており、ネコの甲状腺機能障害が懸念される。
  • 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 - 709 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 mu g/kg/min), esmolol (500 mu g/kg/min), milrinone (25 mu g/kg, IV bolus, followed by 0.5 mu g/kg/min), or phenylephrine (2 mu g/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.
  • 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).
  • Yu Tamura, Hiroshi Ohta, Nozomu Yokoyama, Sue Yee Lim, Tatsuyuki Osuga, Keitaro Morishita, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76 10 1407 - 1410 2014年10月 [査読有り][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-gamma, IL-4, IL-17 and IL-10 and pro-inflammatory cytokines, such as IL-1 beta, IL-6, TNF-alpha., 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.
  • Masahiro Yamasaki, Eriko Harada, Yu Tamura, Sue Yee Lim, Tatsuyuki Ohsuga, Nozomu Yokoyama, Keitaro Morishita, Kensuke Nakamura, Hiroshi Ohta, Mitsuyoshi Takiguchi
    VETERINARY PARASITOLOGY 205 3-4 424 - 433 2014年10月 [査読有り][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 12 h. 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 1 mg/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 1 mg/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. (C) 2014 Elsevier B.V. All rights reserved.
  • Yu Tamura, Hiroshi Ohta, Takuya Kashiide, Jun Matsumoto, Tatsuya Sakurai, Nozomu Yokoyama, Keitaro Morishita, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY PARASITOLOGY 205 1-2 412 - 415 2014年09月 [査読有り][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 (5 mg/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 I 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. (C) 2014 Elsevier B.V. All rights reserved.
  • Hiroshi Ohta, Yuji Sunden, Nozomu Yokoyama, Tatsuyuki Osuga, Sue Yee Lim, Yu Tamura, Keitaro Morishita, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    AMERICAN JOURNAL OF VETERINARY RESEARCH 75 8 746 - 751 2014年08月 [査読有り][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 beta-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 beta-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 beta-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.
  • 左心房機能は心血管薬によりいかに変化するか 正常犬における2D Speckle Tracking法を用いた検討
    大菅 辰幸, 中村 健介, 森田 智也, Lim Sue Yee, 横山 望, 森下 啓太郎, 大田 寛, 滝口 満喜
    日本獣医学会学術集会講演要旨集 157回 479 - 479 (公社)日本獣医学会 2014年08月 [査読有り][通常論文]
  • Yu Tamura, Hiroshi Ohta, Shidow Torisu, Masashi Yuki, Nozomu Yokoyama, Masahiro Murakami, Sue Yee Lim, Tatsuyuki Osuga, Keitaro Morishita, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 156 1-2 32 - 42 2013年11月 [査読有り][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-1 beta, IL-6, TNF-alpha, 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. (C) 2013 Elsevier B.V. All rights reserved.
  • Hiroshi Ohta, Kanae Takada, Shidow Torisu, Masashi Yuki, Yu Tamura, Nozomu Yokoyama, Tatsuyuki Osuga, Sue Yee Lim, Masahiro Murakami, Noboru Sasaki, Kensuke Nakamura, Masahiro Yamasaki, Mitsuyoshi Takiguchi
    VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 155 4 259 - 263 2013年10月 [査読有り][通常論文]
     
    Inflammatory colorectal polyps (ICRPs) in miniature dachshunds are recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and a space-occupying large polyp in the colorectal area, and are thought to be a novel form of inflammatory bowel disease (IBD). In humans, specific cytokine patterns attributed to T helper (Th)1, Th17 and regulatory T cells have important roles in the pathogenesis of IBD. Thus, the aim of the present study was to assess the gene expression of cytokines of T cell subsets in the colorectal mucosa from dogs with ICRPs. Colorectal mucosal specimens from 10 dogs with ICRPs and 14 control dogs were used in this study. Interferon (IFN)-gamma, interleukin (IL)-4, IL-17A and IL-10 mRNA expression was assessed using quantitative real-time PCR. IL-17A mRNA expression was significantly increased in large polyps compared to small polyps and controls. IFN-gamma and IL-10 mRNA expression in large polyps were significantly higher than in controls. There was no significant difference in IL-4 mRNA expression among the three groups. IL-17A is thought to play important roles in the pathogenesis of ICRPs. IL-10 up-regulation could oppose the proinflammatory function of IL-17A. (C) 2013 Elsevier B.V. All rights reserved.
  • 小動物の炎症性腸疾患研究の最前線 ミニチュア・ダックスフンドの炎症性結直腸ポリープの病態
    大田 寛, 田村 悠, 横山 望, 森下 啓太郎, 中村 健介, 山崎 真大, 滝口 満喜
    日本獣医学会学術集会講演要旨集 155回 153 - 153 (公社)日本獣医学会 2013年03月 [査読有り][通常論文]
  • Miho Tanaka, Tatsuya Sakurai, Naoaki Yokoyama, Noboru Inoue, Shin-ichiro Kawazu
    PARASITOLOGY RESEARCH 105 5 1473 - 1477 2009年10月 [査読有り][通常論文]
     
    We have identified the 2-Cys peroxiredoxin (Prx) from a bovine Babesia parasite, B. bovis. Prx is a recently described family of antioxidant enzymes that are highly conserved in eukaryotes and prokaryotes. B. bovis 2-Cys Prx (BbTPx-1) contained two conserved cysteine residues that corresponded to Cys47 and Cys170 of the yeast Prx and the amino acid sequences of two catalytic domains showed significant similarities to those of mammalian typical 2-Cys Prx. The antioxidant activity of the recombinant BbTPx-1 protein expressed in E. coli was demonstrated by a thiol mixed-function oxidation assay. Furthermore, we confirmed that BbTPx-1 was expressed in the cytoplasm of intra-erythrocytic B. bovis merozites. These results suggest that B. bovis likely uses TPx-1 as a way to reduce peroxides as a control of its intracellular redox balance so that it can live and grow in the host cell.
  • N Kuboki, N Yokoyama, N Kojima, T Sakurai, N Inoue, C Sugimoto
    JOURNAL OF PARASITOLOGY 92 2 389 - 393 2006年04月 [査読有り][通常論文]
     
    We demonstrate here that dipalmitoylphosphatidylcholnie (DPPC) liposome has an antitrypanosomal effect, especially against the bloodstream forms (BSFs) of African trypanosomes (Trypanosoma congolense, T. brucei rhodesiense, and T. brucei brucei). The DPPC liposome significantly decreased the in vitro percentage of viable and motile BSF African trypanosomes but only marginally reduced the percentage of viable and motile procyclic form (PCF) of trypanosomes. The DPPC liposome absorption was much more pronounced to BSF than to PCF trypanosomes. Administration of the DPPC liposome showed a slight but significant reduction in the early development of parasitemia in T. congolense-infected mice. These results suggest that parasites were killed by specific binding, of the DPPC liposome to the trypanosomes. This work demonstrates for the first time that a liposome has antitrypanosomal activity.

講演・口頭発表等

その他活動・業績

受賞

  • 2016年03月 クリニカルニュートリション研究会 スカラーシッププログラム奨励研究アワード
     犬の慢性腸症における血中微量元素プロファイルの解析 
    受賞者: 横山 望

共同研究・競争的資金等の研究課題

  • 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 : 2014年04月 -2017年03月 
    代表者 : 大田 寛, 横山 望
     
    犬の炎症性結直腸ポリープ(ICRPs)のポリープ病変部におけるTLR2およびTLR4 mRNAの局在解析をIn situ hybridization法にて行った。その結果、ICRPs のポリープ病変部にてTLR2および TLR4のmRNAは結腸上皮細胞、炎症細胞にてその発現を認めた。また、健常な犬の結腸と比較してそれらのmRNA発現が増加していた。加えて、ICRPs症例の結直腸粘膜を培養し、各種TLRリガンドで刺激したところ、TLR2およびTLR4リガンド刺激でTNF-α mRNAが、TLR9リガンド刺激でIL-1 βmRNAの発現が健常犬よりも増加していた。
  • 犬の慢性腸症における血中微量元素プロファイルの解析
    クリニカルニュートリション研究会:スカラーシッププログラム
    研究期間 : 2014年08月 -2015年10月 
    代表者 : 横山 望


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