Hiroshi Ohta

Hokkaido University, Sapporo, Hokkaido, Japan

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Publications (39)48.39 Total impact

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    [Show abstract] [Hide abstract] ABSTRACT: 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 cording 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 was elevated when the parasites were incubated at 43°C for 1 hr.
    Preview · Article · Apr 2016 · Journal of Veterinary Medical Science
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · Aug 2015 · American Journal of Veterinary Research
  • [Show abstract] [Hide abstract] ABSTRACT: 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 hrs. 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.
    No preview · Article · Sep 2014 · Veterinary Parasitology
  • [Show abstract] [Hide abstract] ABSTRACT: 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 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.
    No preview · Article · Sep 2014 · Veterinary Parasitology
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · Aug 2014 · American Journal of Veterinary Research
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    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text · Article · Jun 2014 · Journal of Veterinary Medical Science
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · May 2014 · Veterinary Radiology & Ultrasound
  • [Show abstract] [Hide abstract] ABSTRACT: MicroRNAs (miRNAs) play a role in the pathogenesis of certain diseases and may serve as biomarkers. Here, we present the first analysis of miRNA expression in the kidneys of healthy cats and dogs. Kidneys were divided into renal cortex (CO) and medulla (MD), and RNA sequence analysis was performed using the mouse genome as a reference. A total of 277, 276, 295, and 297 miRNAs were detected in cat CO, cat MD, dog CO, and dog MD, respectively. By comparing the expression ratio of CO to MD, we identified highly expressed miRNAs in each tissue as follows: 41 miRNAs including miR-192-5p in cat CO; 45 miRNAs including miR-323-3p in dog CO; 78 miRNAs including miR-20a-5p in cat MD; and 11 miRNAs including miR-132-5p in dog MD. Further, the target mRNAs of these miRNAs were identified. These data provide veterinary medicine critical information regarding renal miRNA expression.
    No preview · Article · Apr 2014 · Research in Veterinary Science
  • [Show abstract] [Hide abstract] ABSTRACT: 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.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 × 107 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.The combination of cisplatin, microbubbles, and ultrasound significantly delayed tumor growth as compared with no treatment (after 18 days, 157 ± 55 vs. 398 ± 49 mm3, 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.Ultrasound image-guided anticancer drug delivery may enhance the antitumor effects of drugs without obvious side effects.
    No preview · Article · Jan 2014 · Journal of Medical Ultrasonics
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    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text · Article · Nov 2013 · Journal of Veterinary Medical Science
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · Sep 2013 · Veterinary Immunology and Immunopathology
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    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text · Article · Aug 2013 · Journal of Veterinary Medical Science
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · Jul 2013 · Veterinary Immunology and Immunopathology
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    [Show abstract] [Hide abstract] ABSTRACT: Due to the lack of a gold standard method in canine lipoprotein analysis, it is unclear whether canine high-density lipoprotein (HDL) and low-density lipoprotein (LDL) can be accurately evaluated by the lipoprotein analysis methods used for dogs. This study investigated whether the ultracentrifugation-precipitation (U-P) method was suitable as a gold standard method for analyzing canine lipoprotein. First, the U-P method was compared with a gel permeation high performance liquid chromatography system (GP-HPLC). The concentrations of canine HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C) determined by the U-P method correlated closely with those determined by GP-HPLC. However, the canine HDL-C concentration determined by the U-P method was lower than that by GP-HPLC, and the canine LDL-C concentration by the U-P method was higher than that by GP-HPLC. This study showed that some of the canine HDL could be precipitated with heparin manganese chloride solution. Second, the [HDL] and [LDL] fractions separated by the U-P method were analyzed by LC-MS/MS. The [HDL] fraction was found to contain only apolipoprotein A-I, which is an apolipoprotein of HDL, whereas the [LDL] fraction contained both apolipoprotein A-I and apolipoprotein B-100, which is an apolipoprotein of LDL. This data showed that a certain lipoprotein that includes apolipoprotein A-I might precipitate with canine LDL by use of heparin manganese chloride solution. These results indicated that the U-P method is not currently a gold standard method for analyzing canine lipoproteins.
    Full-text · Article · Jul 2013 · Journal of Veterinary Medical Science
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · Jun 2013 · American Journal of Veterinary Research
  • [Show abstract] [Hide abstract] ABSTRACT: 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®, 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 μg/ml, and microbubble concentration of 2.4 × 105 microbubbles/ml. Exposure duration did not influence the enhancement at the microbubble concentration of 2.4 × 105 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.
    No preview · Article · Oct 2012
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    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text · Article · Aug 2012 · The Japanese journal of veterinary research
  • [Show abstract] [Hide abstract] ABSTRACT: 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.
    No preview · Article · Jul 2012 · Journal of the American Animal Hospital Association
  • [Show abstract] [Hide abstract] ABSTRACT: The stability of the characteristics of the diminazene aceturate (DA)-resistant B. gibsoni isolate was initially determined invitro. 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.
    No preview · Article · May 2012 · Journal of Veterinary Medical Science
  • [Show abstract] [Hide abstract] ABSTRACT: Tritrichomonas suis (=T. foetus) has recently been reported to be a causative agent of chronic large-bowel diarrhea in cats. While the disease was previously attributed to Pentatrichomonas hominis, the etiologic agent for feline trichomonal diarrhea was identified as T. suis. Although feline trichomonosis due to T. suis has been reported at prevalences ranging from 14 to 31% in Europe and the U.S., no reports of the pathogen have been published to date in Japan. In 2008, however, we encountered a case of feline trichomonosis at the Veterinary Teaching Hospital of Hokkaido University. The parasite was identified as T. suis by nested PCR amplification of partial internal transcribed spacer region 1 and 5.8S ribosomal RNA gene sequences with T. suis-specific primers and DNA sequencing of the amplified products. We then conducted surveys for feline trichomonosis in three different animal hospitals using either cultivation and/or PCR-based assays. The results revealed that 13 of 147 samples (8.8%) were positive for T. suis, and that 5 of the 13 infected cats, which ranged between 1 month and 7.5 years-old, showed chronic diarrhea. Seven of the infected cats were purebred and 6 were mixed breed. These findings suggested that feline trichomonosis is prevalent in Japan, and that T. suis may play a role as a causative agent of feline chronic diarrhea.
    No preview · Article · Nov 2011 · Journal of Veterinary Medical Science