Osamu Yamato

Kagoshima University, Kagosima, Kagoshima, Japan

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Publications (133)187.16 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease frequently found in Pembroke Welsh Corgi (PWC) dogs, and it has clinical and pathologic similarities to human amyotrophic lateral sclerosis. Autophagy is a major intracellular protein degradation system. Abnormalities of autophagy-resulting in cell death through mechanisms called type II programmed cell death-have recently been reported to occur in various neurodegenerative diseases, including amyotrophic lateral sclerosis. Thus, the distribution and expression levels of proteins involved in autophagy were examined in the spinal cords of 8 PWC dogs suffering from DM with superoxide dismutase mutation, 5 non-DM PWC dogs, and 6 Beagle dogs without neurologic signs. There was no significant difference in the ratio of neurons with microtubule-associated protein light chain 3 (LC3)-positive somata relative to those that were LC3 negative among the 3 groups, whereas the number of LC3-positive neurites was significantly increased in DM dogs. Punctate LC3 immunoreactivity did not colocalize with a lysosome marker, LAMP2 (lysosome-associated membrane protein 2). NBR1 (neighbor of BRCA gene 1) was localized mostly in reactive astrocytes, whereas there were p62 (p62/A170/SQSTM1)-positive foci in the neuropil of the spinal cord of DM dogs. Western blotting revealed in DM dogs the decreased expression of Beclin1 and Atg16 L, which are molecules involved in formation of the isolation membrane. These findings suggest that altered autophagosome degradation may result in LC3 and p62 accumulation in the DM spinal cord, whereas the early stage of membrane formation is likely to be downregulated. © The Author(s) 2015.
    Veterinary Pathology 03/2015; DOI:10.1177/0300985815570070 · 2.04 Impact Factor
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    ABSTRACT: Erythrocyte pyruvate kinase (PK) deficiency is an inherited glycolytic erythroenzymopathy caused by mutations of the PKLR gene. A causative mutation of the feline PKLR gene was originally identified in Abyssinian and Somali cats in the U.S.A. In the present study, a TaqMan probe-based real-time PCR genotyping assay was developed and evaluated for rapid genotyping and large-scale screening for this mutation. Furthermore, a genotyping survey was carried out in a population of four popular purebred cats in Japan to determine the current mutant allele frequency. The assay clearly displayed all genotypes of feline PK deficiency, indicating its suitability for large-scale survey as well as diagnosis. The survey demonstrated that the mutant allele frequency in Abyssinian and Somali cats was high enough to warrant measures to control and prevent the disease. The mutant allele frequency was relatively low in Bengal and American shorthair cats; however, the testing should still be carried out to prevent the spread of the disease. In addition, PK deficiency should always be considered in the differential diagnosis of anemia in purebred cats in Japan as well as worldwide.
    Journal of Veterinary Medical Science 02/2015; DOI:10.1292/jvms.14-0600 · 0.88 Impact Factor
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    ABSTRACT: Plastic hematocrit tubes (PHTs) are convenient tools for electron microscopy (EM) of peripheral blood buffy coats, and the PHT-EM technique is expected to be a practical method for veterinary clinical medicine. In this study, fixatives composed of various concentrations of sucrose, glutaraldehyde, and phosphate buffer (PB) were tested for preparing canine and feline buffy coats. The highest quality images were obtained using a fixative consisting of 2.5% glutaraldehyde in 0.1 m PB, and it was concluded that this method allows clinicians who are inexperienced in histological techniques can conveniently transport buffy coat samples to diagnostic laboratories for analysis by EM.
    Anantomia Histologia Embryologia 08/2014; DOI:10.1111/ahe.12143 · 0.74 Impact Factor
  • The Veterinary record 06/2014; 175(7). DOI:10.1136/vr.102015 · 1.63 Impact Factor
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    ABSTRACT: This retrospective study aimed (1) to confirm the relationship between pre- and postpartum metabolic parameters and postpartum reproductive performance and (2) to clarify seasonal characteristics of the metabolic parameters by using our metabolic profile test (MPT) database of Japanese Black breeding herds. Evaluation 1: MPT databases of multiparous cows whose blood samples were collected at prepartum and postpartum were divided into 2 groups according to calving interval, and each MPT parameter was compared. Evaluation 2: The same MPT databases used in Evaluation 1 were divided into 2 groups according to the sampling period. Two sampling periods were defined, from July through October (summer; mean temperature during these months, mean air temperature: 26.3°C) and outside these 4 months (non-summer; mean temperature during these months, mean air temperature: 14.6°C), according to the main dietary roughage fed such as barnyard grass silage from digitaria in summer or Italian ryegrass and oats hay in non-summer months. Significant differences were found in prepartal total protein and postpartal g-glutamyltransferase in Evaluation 1. In Evaluation 2, significant differences were found in prepartal and postpartal total protein, albumin/globulin ratio, and glucose. Clear seasonal differences in MPT results emphasize the usefulness of the MPT in breeding cattle herds fed home-pasture roughage and suggest that unsatisfactory reproductive performance during hot periods reflects inadequate nutritional content of the diet and possible reduced feed intake due to heat stress.
    Journal of veterinary science (Suwŏn-si, Korea) 03/2014; 15(2). DOI:10.4142/jvs.2014.15.2.283 · 1.14 Impact Factor
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    ABSTRACT: Several reports have described magnetic resonance (MR) findings in canine and feline lysosomal storage diseases such as gangliosidoses and neuronal ceroid lipofuscinosis. Although most of those studies described the signal intensities of white matter in the cerebrum, findings of the corpus callosum were not described in detail. A retrospective study was conducted on MR findings of the corpus callosum as well as the rostral commissure and the fornix in 18 cases of canine and feline lysosomal storage diseases. This included 6 Shiba Inu dogs and 2 domestic shorthair cats with GM1 gangliosidosis; 2 domestic shorthair cats, 2 familial toy poodles, and a golden retriever with GM2 gangliosidosis; and 2 border collies and 3 chihuahuas with neuronal ceroid lipofuscinoses, to determine whether changes of the corpus callosum is an imaging indicator of those diseases. The corpus callosum and the rostral commissure were difficult to recognize in all cases of juvenile-onset gangliosidoses (GM1 gangliosidosis in Shiba Inu dogs and domestic shorthair cats and GM2 gangliosidosis in domestic shorthair cats) and GM2 gangliosidosis in toy poodles with late juvenile-onset. In contrast, the corpus callosum and the rostral commissure were confirmed in cases of GM2 gangliosidosis in a golden retriever and canine neuronal ceroid lipofuscinoses with late juvenile- to early adult-onset, but were extremely thin. Abnormal findings of the corpus callosum on midline sagittal images may be a useful imaging indicator for suspecting lysosomal storage diseases, especially hypoplasia (underdevelopment) of the corpus callosum in juvenile-onset gangliosidoses.
    PLoS ONE 12/2013; 8(12):e83455. DOI:10.1371/journal.pone.0083455 · 3.53 Impact Factor
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    ABSTRACT: A single nucleotide substitution (c.-6-180T>G) associated with resistance to phenobarbital therapy has been found in the canine MDR1/ABCB1 gene in Border Collies with idiopathic epilepsy. In the present study, a PCR-restriction fragment length polymorphism assay was developed for genotyping this mutation, and a genotyping survey was carried out in a population of 472 Border Collies in Japan to determine the current allele frequency. The survey demonstrated the frequencies of the T/T wild type, T/G heterozygote, and G/G mutant homozygote to be 60.0%, 30.3%, and 9.8%, respectively, indicating that the frequency of the mutant G allele is extremely high (24.9%) in Border Collies. The results suggest that this high mutation frequency of the mutation is likely to cause a high prevalence of phenobarbital-resistant epilepsy in Border Collies.
    Disease markers 11/2013; 35(6):669-72. DOI:10.1155/2013/695918 · 2.17 Impact Factor
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    ABSTRACT: GM2 gangliosidosis variant 0 (Sandhoff disease, SD) is a fatal, progressive neurodegenerative lysosomal storage disease caused by mutations of the HEXB gene. In canine SD, a pathogenic mutation (c.283delG) of the canine HEXB gene has been identified in toy poodles. In the present study, a TaqMan probe-based real-time PCR genotyping assay was developed and evaluated for rapid and large-scale genotyping and screening for this mutation. Furthermore, a genotyping survey was carried out in a population of toy poodles in Japan to determine the current mutant allele frequency. The real-time PCR assay clearly showed all genotypes of canine SD. The assay was suitable for large-scale survey as well as diagnosis, because of its high throughput and rapidity. The genotyping survey demonstrated a carrier frequency of 0.2%, suggesting that the current mutant allele frequency is low in Japan. However, there may be population stratification in different places, because of the founder effect by some carriers. Therefore, this new assay will be useful for the prevention and control of SD in toy poodles.
    Journal of Veterinary Medical Science 10/2013; 76(2). DOI:10.1292/jvms.13-0443 · 0.88 Impact Factor
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    ABSTRACT: In this study, age-dependent histological changes in the kidneys of Brown Norway rat, a strain useful for conducting aging research, were evaluated. Examination was performed at 3, 12, 18, 24 and 30 months of age. Sclerotic and hypertrophic changes of the glomeruli were observed, and quantitative scores of these changes persistently increased with age. A marginal increase in scores was observed for glomerular cystic changes and tubulointerstitial damage. Further, urothelial hyperplasia was observed in the renal papillae, particularly at 30 months of age. In conclusion, the findings of the present study demonstrate that the Brown Norway strain exhibits persistent, but mild progression of age-dependent renal histological changes.
    Journal of Veterinary Medical Science 10/2013; 76(2). DOI:10.1292/jvms.13-0431 · 0.88 Impact Factor
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    ABSTRACT: Angiotensin-converting enzyme (ACE) is a key enzyme in the renin-angiotensin system (RAS). ACE2 is a newly identified member of the RAS. The present immunohistochemical study focused on changes in intrarenal ACE and ACE2 immunoreactivity in feline and canine chronic kidney disease (CKD). ACE immunoreactivity was predominantly observed in the brush border of the proximal tubules in dogs and cats. ACE immunoreactivity was lower in CKD kidneys than in normal kidneys, and quantitative analysis demonstrated negative correlations between ACE and renal tissue damage in dogs. ACE2 immunoreactivity was also detected in the proximal tubules; it increased or decreased with CKD in dogs, depending on the renal region assessed. The changes in ACE and ACE2 in CKD were associated with the plasma creatinine concentration in dogs. Findings from dogs with glomerulonephritis were similar to those from dogs with non-glomerulonephritis. The present study suggests that changes in the intrarenal expression of ACE and ACE2 contribute to the pathological mechanisms of canine CKD, but not to the mechanisms of feline CKD.
    Journal of Veterinary Medical Science 09/2013; 76(1). DOI:10.1292/jvms.13-0314 · 0.88 Impact Factor
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    ABSTRACT: Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease that is frequently found in Pembroke Welsh Corgi (PWC) dogs. Canine DM is potentially a spontaneous animal model for human amyotrophic lateral sclerosis (ALS) because of similar lesions and the involvement of superoxide dismutase 1 (SOD1) mutation. However, the ventral horn lesion in DM has not been characterized in detail. Glutamate excitotoxicity due to deficiency of the glutamine-glutamate cycle has been implicated in neuron death in ALS. Thus, we examined 5 PWC dogs with an SOD1 mutation that were affected by DM, 5 non-DM PWC dogs, and 5 Beagle dogs without neurologic signs to assess the neuronal changes and the expression levels of 2 glial excitatory amino acid transporters (glutamate transporter 1 [GLT-1] and glutamate/aspartate transporter [GLAST]). The number of neurons in the spinal ventral horns of the DM dogs was significantly decreased, whereas no change was found in the cell size. Chromatolysis, lipofuscin-laden neurons, and marked synapse loss were also observed. GLT-1 expression was strikingly decreased in DM dogs, whereas GLAST expression showed no significant change. The results indicate that excitotoxicity related to the reduced expression of GLT-1, but not GLAST, may be involved in neuron loss in DM, as in human ALS, whereas intraneuronal events may differ between the 2 diseases.
    Veterinary Pathology 07/2013; 51(3). DOI:10.1177/0300985813495899 · 2.04 Impact Factor
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    ABSTRACT: Canine GM1 gangliosidosis is a fatal disease in the Shiba Inu breed, which is one of the most popular traditional breeds in Japan and is maintained as a standard breed in many countries. Therefore, it is important to control and reduce the prevalence of GM1 gangliosidosis for maintaining the quality of this breed and to ensure supply of healthy dogs to prospective breeders and owners. This molecular epidemiological survey was performed to formulate an effective strategy for the control and prevention of this disease. The survey was carried out among 590 clinically unaffected Shiba Inu dogs from the 8 districts of Japan, and a genotyping test was used to determine nation-wide and regional carrier frequencies. The number and native district of affected dogs identified in 16 years from 1997 to April 2013 were also surveyed retrospectively. Of the 590 dogs examined, 6 dogs (1.02%, 6/590) were carriers: 3 dogs (2.27%, 3/132) from the Kinki district and the other 3 dogs from the Hokkaido, Kanto, and Shikoku districts. The retrospective survey revealed 23 affected dogs, among which, 19 dogs (82.6%) were born within the last 7 years. Of the 23 affected dogs, 12 dogs (52.2%) were from the Kinki district. Pedigree analysis demonstrated that all the affected dogs and carriers with the pedigree information have a close blood relationship. Our results showed that the current carrier frequency for GM1 gangliosidosis is on the average 1.02% in Japan and rather high in the Kinki district, which may be related to the high prevalence observed over the past 16 years in this region. This observation suggests that carrier dogs are distributed all over Japan; however, kennels in the Kinki district may face an increased risk of GM1 gangliosidosis. Therefore, for effective control and prevention of this disease, it is necessary to examine as many breeding dogs as possible from all regions of Japan, especially from kennels located in areas with high prevalence and carrier frequency.
    BMC Veterinary Research 07/2013; 9(1):132. DOI:10.1186/1746-6148-9-132 · 1.74 Impact Factor
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    ABSTRACT: Canine degenerative myelopathy is an adult-onset, progressive neurodegenerative disease that occurs in multiple dog breeds, particularly Pembroke Welsh Corgis. Recently, a degenerative myelopathy-associated mutation of the canine SOD1 gene was identified as c.118G>A (p.E40K). In the present study, genotyping assays using conventional and real-time PCR methods were developed, and a preliminary genotyping survey was performed on 122 randomly selected Pembroke Welsh Corgis without any degenerative myelopathy-related clinical signs to determine the current allele frequency in Japan. Both of the assays provided clear-cut genotyping. The survey demonstrated the frequencies of the G/G wild-type, G/A heterozygote and A/A homozygote to be 9.0, 42.6 and 48.4%, respectively, indicating that the prevalence of the mutant A allele (69.7%) in Pembroke Welsh Corgis is extremely high in Japan.
    Journal of Veterinary Medical Science 01/2013; 75(6). DOI:10.1292/jvms.12-0451 · 0.88 Impact Factor
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    ABSTRACT: Background: Canine GM1 gangliosidosis is a fatal disease in the Shiba Inu breed, which is one of the most popular traditional breeds in Japan and is maintained as a standard breed in many countries. Therefore, it is important to control and reduce the prevalence of GM1 gangliosidosis for maintaining the quality of this breed and to ensure supply of healthy dogs to prospective breeders and owners. This molecular epidemiological survey was performed to formulate an effective strategy for the control and prevention of this disease. Results: The survey was carried out among 590 clinically unaffected Shiba Inu dogs from the 8 districts of Japan, and a genotyping test was used to determine nation-wide and regional carrier frequencies. The number and native district of affected dogs identified in 16 years from 1997 to June 2013 were also surveyed retrospectively. Of the 590 dogs examined, 6 dogs (1.02%, 6/590) were carriers: 3 dogs (2.27%, 3/132) from the Kinki district and the other 3 dogs from the Hokkaido, Kanto, and Shikoku districts. The retrospective survey revealed 23 affected dogs, among which, 19 dogs (82.6%) were born within the last 7 years. Of the 23 affected dogs, 12 dogs (52.2%) were from the Kinki district. Pedigree analysis demonstrated that all the affected dogs and carriers with the pedigree information have a close blood relationship. Conclusions: Our results showed that the current carrier frequency for GM1 gangliosidosis is on the average 1.02% in Japan and rather high in the Kinki district, which may be related to the high prevalence observed over the past 16 years in this region. This observation suggests that carrier dogs are distributed all over Japan; however, kennels in the Kinki district may face an increased risk of GM1 gangliosidosis. Therefore, for effective control and prevention of this disease, it is necessary to examine as many breeding dogs as possible from all regions of Japan, especially from kennels located in areas with high prevalence and carrier frequency.
    BMC Veterinary Research 01/2013; 9(132). · 1.74 Impact Factor
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    ABSTRACT: Ten reared cows of a Japanese Black cattle herd in Kagoshima prefecture, Japan, exhibited extremely low blood urea nitrogen (BUN) concentration (2.6 ± 0.6 mg/dL). Examination of dietary feed nutrition and relevant pastureland soil content suggested a correlation with crude protein (CP) deficiency or unbalanced nutritional dietary feeds. Thirteen months after the introduction of a dietary remedial measure (bean cake supplementation), BUN, total cholesterol and albumin concentration from five of the original 10 cows increased significantly compared with their values of before the dietary remedy. The postpartum day open period was significantly lower after the dietary remedial measure than that before it. The abnormally low BUN levels of the cattle herd may be due to inadequate dietary nutritional content, primarily from the imbalance of total digestible nutrient and CP of the feed and far lower han average CP value. In conclusion, routine examination of serum biochemical parameters in Japanese Black breeding cattle may be a useful strategy for determining subclinical metabolic failure of cattle herds, and consequently, its effect on reproductive performance of the herd.
    Animal Science Journal 12/2012; 84(5). DOI:10.1111/asj.12012 · 1.04 Impact Factor
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    ABSTRACT: The study aims were (1) to confirm the effects of nutritional improvement in prepartal and postpartal periods, monitored using the serum metabolic profile test (MPT) and reproductive performance, and (2) to clarify regional characteristics of the MPT results within our jurisdiction by using our MPT database. Experiment 1: Among 42 breeding cattle herds in our jurisdiction mainly fed home-pasture roughage, 3 experimental herds showing subnormal BUN levels were selected and compared with 1 representative excellent herd. Dietary remedial measures were implemented from feed analysis in each herd. Blood urea nitrogen (BUN) concentration in all 3 herds increased significantly, and open days postpartum in 2 of the herds were significantly reduced, compared with values before dietary supplementation. Experiment 2: Thirty-seven herds within our jurisdiction were grouped into 3 categories (Area 1, 2, and 3) by location and soil condition of the herd pastureland. The MPT and reproductive performance in cows whose blood samples were collected at both prepartum (60-20 days before calving) and postpartum (30-90 days after calving) were compared among the 3 areas. Significant regional differences were found in prepartal albumin, total cholesterol, BUN, and glucose and postpartal BUN, glucose, and open days (P<0.05). Overall, the MPT (especially BUN) might be useful for determining the metabolic nutritional status of breeding cattle herds, particularly those fed home-pasture roughage. Additionally, poor/unsatisfactory reproductive performance of beef breeding cattle herds probably reflects inadequate nutritional content of the diet, possibly arising from regional pastureland differences.
    Journal of Veterinary Medical Science 11/2012; 75(4). DOI:10.1292/jvms.12-0441 · 0.88 Impact Factor
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    ABSTRACT: GM1 gangliosidosis is a fatal, progressive neurodegenerative lysosomal storage disease caused by mutations in the β-galactosidase (GLB1) gene. In feline GM1 gangliosidosis, a pathogenic mutation (c.1448G>C) in the feline GLB1 gene was identified in Siamese cats in the United States and Japan and in Korat cats in Western countries. The present study found the homozygous c.1448G>C mutation in 2 apparent littermate native kittens in Bangladesh that were exhibiting neurological signs. This is the first identification of GM1 gangliosidosis in native domestic cats in Southeast Asia. This pathogenic mutation seems to have been present in the domestic cat population in the Siamese region and may have been transferred to pure breeds such as Siamese and Korat cats originating in this region.
    Journal of Veterinary Medical Science 11/2012; 75(3). DOI:10.1292/jvms.12-0307 · 0.88 Impact Factor
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    ABSTRACT: The association of renin and angiotensin II, which are potent components of the renin-angiotensin system, with the severity of chronic renal disease was investigated immunohistochemically in dogs and cats. Immunoreactivities of renin and angiotensin II were evaluated quantitatively, and their correlations with the degrees of glomerulosclerosis, glomerular hypertrophy, interstitial cell infiltration, and interstitial fibrosis were statistically analyzed. Immunoreactivities for renin were detected in afferent arteries in both dogs and cats. The score of renin-positive signals showed no correlation with plasma creatinine concentration or any of the histopathological parameters, except for the diameter of glomeruli in dogs. Immunoreactivities for angiotensin II were detected in tubules (primarily proximal tubules) and interstitial mononuclear cells in both dogs and cats. The score of tubular angiotensin II correlated with glomerulosclerosis and cell infiltration in cats but not in dogs. The score of interstitial angiotensin II correlated with plasma creatinine concentration, glomerulosclerosis, cell infiltration, and fibrosis in dogs and with glomerulosclerosis and cell infiltration in cats. In conclusion, the results of the study suggest that intrarenal renin-angiotensin system is correlated with the severity of kidney disease, with the underlying mechanism differing between dogs and cats.
    Journal of Veterinary Medical Science 09/2012; 75(2). DOI:10.1292/jvms.12-0314 · 0.88 Impact Factor
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    ABSTRACT: To evaluate a radioprotective effect of sodium n-propyl thiosulfate (NPTS) and sodium 2-propenyl thiosulfate (2PTS) derived from onions and garlic, respectively, rat hepatoma H4IIE cells and mouse lymphoma L5178Y cells were preincubated with each of these compounds for 48 hours at 37°C before receiving 10 Gy of X-ray irradiation. Cell damage caused by the irradiation was quantified as comet tail moment, which represents the degree of DNA damage. X-ray-induced DNA damage was significantly decreased in both H4IIE and L5178Y cells by micromolar concentrations of NPTS and 2PTS compared with the control without the compounds. The protective effect was more potent with 2PTS than NPTS. Onions and garlic have antiradiation potential.
    The Scientific World Journal 07/2012; 2012:846750. DOI:10.1100/2012/846750 · 1.73 Impact Factor

Publication Stats

980 Citations
187.16 Total Impact Points

Institutions

  • 2007–2015
    • Kagoshima University
      • • Department of Veterinary Medicine
      • • Faculty of Veterinary Medicine
      • • Faculty of Agriculture
      Kagosima, Kagoshima, Japan
  • 2011
    • Miyazaki University
      • Veterinary Teaching Hospital
      Миядзаки, Miyazaki, Japan
  • 2009
    • Osaka Prefecture University
      • Laboratory of Veterinary Pathology
      Sakai, Osaka-fu, Japan
  • 1992–2009
    • Hokkaido University
      • • Laboratory of Internal Medicine
      • • Department of Veterinary Clinical Science
      • • Department of Internal Medicine
      • • School of Veterinary Medicine
      Sapporo, Hokkaidō, Japan
  • 2002
    • Nanjing Agricultural University
      • College of Food Science and Technology
      Nanjing, Jiangsu Sheng, China
  • 1999
    • Zagazig University
      Ez Zaqāzīq, Eastern Province, Egypt