Papers - HIRAI Takuya
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Hirai T., Nunoya T., Ihara T., Kusanagi K., Kato T., Shibuya K.
Journal of Veterinary Medical Science 65 ( 9 ) 1041 - 1045 2003.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Five 2 day-old colostrum-deprived piglets were inoculated with tissue homogenates from pigs with postweaning multisystemic wasting syndrome. One of the five piglets developed icterus and died 23 days post-inoculation. Histologic examination revealed acute hepatitis. Porcine circovirus type 2 (PCV-2) antigen and nucleic acid were detected in hepatocytes and phagocytic cells. Ultrastructurally, hepatocytes and phagocytic cells had large numbers of cytoplasmic inclusions, which were composed of electron-dense paracrystalline arrays of small non-enveloped viral particles approximately 17 nm in diameter. Apoptotic hepatocytes were confirmed by the TUNEL method and electron microscopic examination. These findings may indicate that hepatocellular necrosis is associated with replication of PCV-2. Apoptosis of hepatocytes also contributes to the pathogenesis of hepatic lesions in this case.
DOI： 10.1292/jvms.65.1041
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Unilateral ocular subalbinism in a laboratory Beagle dog.
Shibuya K, Hirai T, Nunoya T, Sugimoto K.
Vet Ophthalmol 6 ( 2 ) 169 - 172 2003.1
Language：English Publishing type：Research paper (scientific journal)
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Dermatotoxicity in the Hypotrichotic(htr) Rabbit Derived from the Japanese White(JW-NIBS) Strain Rabbit. Reviewed
Miheko Ihara, Kazumoto Shibuya, Tetsuo Nunoya, Makoto Mizutani, Hajime Yazawa, Takuya Hirai
J Toxicol Pathol 15 153 - 159 2002.4
Language：English Publishing type：Research paper (scientific journal)
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Ihara M., Shibuya K., Nunoya T., Mizutani M., Yazawa H., Hirai T.
Journal of Toxicologic Pathology 15 ( 3 ) 153 - 159 2002
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Toxicologic Pathology
Utility of Japanese White rabbit mutants with hypotrichosis (htr strain) was investigated in dermal toxicity studies. In the primary irritation study, the primary irritation indices (P.I.I.) by application of hexachlorophene and 3, 3′, 4′, 5-tetrachlorosalicylanilide (TCSA) were higher in the htr rabbits than in the control, haired rabbits. The P.I.I. by application of Tween 80 and sodium lauryl sulfate (SLS) were similar between the htr rabbits and the control rabbits. In the 16-day cumulative irritation study, irritation scores induced by SLS and sodium hydroxide were lower in the htr rabbits than in the control rabbits throughout the observation periods. However, approximately 30% of the dorsal skin of the control rabbits underwent the anagen phase of the hair cycle during the cumulative periods, resulting in difficulty to apply the chemicals and to estimate the skin reactions. In the phototoxicity study, irritation scores of the htr rabbits treated with 8-methoxypsoralen and TCSA were similar to those of the control rabbits. These results revealed advantages of the htr rabbits in the administration of test chemicals and the evaluation of skin reactions, suggesting the usefulness of htr rabbits for dermal toxicity studies.
DOI： 10.1293/tox.15.153
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Dual infection with PCV-2 and porcine epidemic diarrhoea virus in neonatal piglets Reviewed
Hirai T., Nunoya T., Ihara T., Kusanagi K., Shibuya K.
Veterinary Record 148 ( 15 ) 482 - 484 2001.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Veterinary Record
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Dual infection with PCV-2 and porcine epidemic diarrhoea virus in neonatal piglets.
Hirai T, Nunoya T, Ihara T, Kusanagi K, Shibuya K..
Vet Rec 148 ( 15 ) 482 - 484 2001.4
Language：English Publishing type：Research paper (scientific journal)
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Hirai T., Mizutani M., Ochiai K., Umemura T., Itakura C.
Acta Neuropathologica 97 ( 6 ) 552 - 556 1999.6
Language：English Publishing type：Research paper (scientific journal) Publisher：Acta Neuropathologica
The neurotoxic effects caused by chronic exposure to 2,5-hexanedione (2,5-HD) were investigated in normal and neurofilament (NF)-deficient quail (Quv strain). These quail were given 175 mg/kg per day of 2,5-HD intraperitoneally for 24 weeks. Five of nine normal quail showed clumsy gait. They had NF-rich axonal swellings in the distal parts of the peripheral nerves, ventral and lateral funiculus of the cervical cord, and cerebellar peduncles. Axonal degeneration consisting of accumulation of mitochondria, vesicles, microtubules and dense bodies was found distal to the axonal swellings. Testicular atrophy appeared in two normal quail. In contrast, four of nine Quv quail showed systemic tonic convulsion, and died of respiratory paralysis within 6 days. No significant changes in the nervous system or testis of these four dead Quv quail. The five other Quv quail survived and did not show any neurological signs. Again, no significant changes were detected in the nervous system or testis of the surviving Quv quail. The present study revealed that distal axonal degeneration did not occur without NF accumulation. These results suggest that NF accumulation is an essential factor in the development of distal axonopathy in γ-diketone neuropathy.
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Neurotoxic effects of 2,5-hexanedione on normal and neurofilament-deficient quail.
Hirai T, Mizutani M, Kimura T, Ochiai K, Umemura T, Itakura C.
Toxicol Pathol 27 ( 3 ) 348 - 353 1999.5
Language：English Publishing type：Research paper (scientific journal)
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Neurotoxic Effects of 2,5-Hexanedione on Normal and Neurofilament-Deficient Quail Reviewed
Hirai T., Mizutani M., Kimura T., Ochiai K., Umemura T., Itakura C.
Toxicologic Pathology 27 ( 3 ) 348 - 353 1999.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Toxicologic Pathology
The neurotoxic effects of 2,5-hexanedione (2,5-HD) were investigated using neurofilament (NF)-deficient (Quv) Japanese quail in comparison with normal Japanese quail. Both Quv and normal Japanese quail were inoculated intraperitoneally with 350 mg/kg/day 2,5-HD for 6 consecutive wk. The results of 2,5-HD exposure differed substantially between the 2 strains of Japanese quail. The 2,5-HD-exposed normal quail showed leg paralysis about 4 wk after initiation of dosing. Some treated normal quail fell into dysstasia and died of nutritional disturbances. Histologically, 2,5-HD-treated normal quail had NF-rich axonal swellings and degeneration in the distal parts of the peripheral nerves, spinal cord, and cerebellar peduncles. In contrast, 2,5-HD-injected Quv quail showed tonic convulsion, ataxia gait, severe quivering, and excitation about 2-3 days after administration. Some treated Quv birds died immediately after systemic tonic convulsion, probably because of asphyxia. Although all treated Quv quail showed neurologic signs, there were no recognizable 2,5-HD-induced lesions in the nervous system. After about 4-6 wk of dosing, 2,5-HD induced distal axonopathy in normal quail and acute neurotoxicity in Quv quail. © 1999, Sage Publications. All rights reserved.
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Distal axonopathy does not occur without neurofilament accumulation in gamma-diketone neuropathy: comparative studies of normal and neurofilament-deficient quail.
Hirai T, Mizutani M, Ochiai K, Umemura T, Itakura C.
Acta Neuropathol 97 ( 6 ) 552 - 556 1999.1
Language：English Publishing type：Research paper (scientific journal)
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Apocrine gland tumor of the eyelid in a dog.
Hirai T, Mubarak M, Kimura T, Ochiai K, Itakura C.
Vet Pathol 34 ( 3 ) 232 - 234 1997.5
Language：English Publishing type：Research paper (scientific journal)
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Apocrine Gland Tumor of the Eyelid in a Dog Reviewed
Hirai T., Mubarak M., Kimura T., Ochiai K., Itakura C.
Veterinary Pathology 34 ( 3 ) 232 - 234 1997.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Veterinary Pathology
A 13-year-old male Shetland Sheepdog with progressive exophthalmos had a neoplastic mass in the ocular adnexa. Histologically, this neoplasm was composed of duct-forming epithelial cells with decapitation secretion. Tumor cells invaded the globe through the tunica conjunctiva and replaced the vitreous body. The cornea, iris, ciliary body, and retina were extensively destroyed. Both the epithelial and spindle-shaped myoepithelial cells showed nuclear atypia and mitotic activity in the globe. The primary tumor was diagnosed as adenocarcinoma, probably originating from apocrine sweat glands of the eyelid, and the infiltrating intraocular neoplasm was diagnosed as a malignant mixed tumor.
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Age-related changes in the olfactory system of dogs.
Hirai T, Kojima S, Shimada A, Umemura T, Sakai M, Itakura C.
Neuropathol Appl Neurobiol 22 ( 6 ) 531 - 539 1996.12
Language：English Publishing type：Research paper (scientific journal)
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Age-related changes in the olfactory system of dogs Reviewed
Hirai T., Kojima S., Shimada A., Umemura T., Sakai M., Itakura C.
Neuropathology and Applied Neurobiology 22 ( 6 ) 531 - 539 1996
Language：English Publishing type：Research paper (scientific journal) Publisher：Neuropathology and Applied Neurobiology
Age-related changes in the olfactory system were examined in 22 dogs ranging in age from 10 to 19 years old. Atrophic changes with degeneration were observed in the olfactory epithelium of dogs older than 14 years; the changes were prominent in the dogs over the age of 17 years. Immunohistochemistry using an anti-carnosine antibody, which is a marker for the olfactory cells, demonstrated a decrease in the number of olfactory cells. Electron microscopy also showed a decrease in the number of cilia of olfactory cells and microvilli of supporting cells. Atrophic changes with the features of regeneration were rarely observed in the aged animals. Lipofuscin-like granules in the olfactory epithelium became prominent with age. These age-related changes were similar to those reported in the olfactory epithelium of man and rats. Dystrophic neurites were not detected by a modified Bielschowsky stain or by neurofilament, synaptophysin and tau immunohistochemistry in the olfactory mucosa. There was no β-amyloid- and ubiquitin-immunostaining in the olfactory mucosa. Senile brain changes, including cerebrovascular amyloidosis, age-related astrocytic gliosis and ubiquitin deposits were found in the olfactory bulb, although neurofibrillary tangles and senile plaques were either by a modified detected or by β-amyloid immunohistochemistry. These results indicate that dog may be a useful animal model to study the age-related changes in the olfactory system in man.