Papers - HIRAI Takuya
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Detection of bovine respiratory disease complex-related pathogens in nasopharynx-associated lymphoid tissue. Reviewed
Hegazy AA, Nakai M, Fuke N, Hussein AE, Kondo H, Hirai T.
J Vet Diagn Invest 37 ( 2 ) 284 - 297 2025.3
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Histopathological findings of the nasopharynx-associated lymphoid tissue of pigs co-infected with porcine circovirus 2 and porcine reproductive and respiratory syndrome virus. Reviewed
Toyama K, Hirai T, Sueyoshi M, Zhou Z, Niazi AM, Kawaguchi N, Fuke N, Yamaguchi R.
J Vet Med Sci. 2022.10
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
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Niazi A.M., ZiHeng Z., Fuke N., Toyama K., Habibi W.A., Kawaguchi N., Yamaguchi R., Hirai T.
Journal of Comparative Pathology 197 23 - 34 2022.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
Porcine respiratory disease complex, which is caused by a combination of pathogens, including swine influenza A virus (SIV) and porcine reproductive respiratory syndrome virus (PRRSV), results in significant economic losses in pig production systems. Nasopharynx-associated lymphoid tissue (NALT) plays an important role in the uptake of pathogens and defence of the nasal mucosa in rodents and humans. We characterized NALT M cells in pigs and detected SIV antigen and PRRSV nucleic acid in NALT using histopathological, immunohistochemical and in-situ hybridization analyses. All SIV- and PRRSV-positive cases examined had suppurative nasopharyngitis and pneumonia. M cells were detected by immunohistochemistry and the distribution of M cells showed an increase in the middle section of NALT. SIV antigen was detected in M cells and PRRSV nucleic acid was demonstrated in the cytoplasm of macrophages in NALT. We believe that SIV and PRRSV infection in the upper respiratory tract induces local immunosuppression and these results confirm that swine NALT is a location for virus replication and may be strongly associated with the development of pneumonia in pigs.
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Rhabdomyolysis, myoglobinuric nephrosis, and crystalline nephropathy in a captive bottlenose dolphin Reviewed
Nueangphuet P., Hamano T., Hirai T., Sakaguchi Y., Sonoda H., Otsuka M., Yamato O., Hobo S., Ikeda M., Yamaguchi R.
Journal of Veterinary Diagnostic Investigation 34 ( 4 ) 668 - 673 2022.7
Authorship：Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Diagnostic Investigation
A 5-y-old female bottlenose dolphin (Tursiops truncatus) from an aquarium in Japan had clinical signs of anorexia, vomiting, and bradykinesia. Enrofloxacin and lactated Ringer solution were administered for treatment of bacterial infection and for rehydration. Elevations of creatine kinase and aspartate aminotransferase activities were detected on day 4 of treatment, indicating that rhabdomyolysis had developed on day 3. On day 5, serum creatinine and urea concentrations increased and remained high throughout the remaining treatment; the dolphin died on day 16. Postmortem examination revealed massive necrosis of the longissimus dorsi muscles. Histologic examination revealed extensive necrosis of skeletal myofibers, multifocal renal tubular necrosis with intratubular casts and crystals, and suppurative bronchopneumonia. The renal casts labeled positively with anti-myoglobin antibody; expression of aquaporin-1 was decreased in renal tubules compared to normal kidney tissue. To our knowledge, this description of clinicopathologic findings of rhabdomyolysis leading to acute kidney injury with concomitant crystalline nephropathy has not been reported previously in a bottlenose dolphin.
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Niazmand M., Hirai T., Ito S., Habibi W., Noori J., Hasheme R., Yamaguchi R.
Journal of Wildlife Diseases 55 ( 4 ) 804 - 811 2019.10
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Wildlife Diseases
We performed postmortem examinations on seven Misaki feral horses (Equus caballus) and evaluated Misaki feral horses, Japanese wild boars (Sus scrofa leucomystax), domestic pigs (Sus scrofa), and wild Japanese macaques (Macaca fuscata fuscata) from 2015 to 2017 in Cape Toi, Kushima, Miyazaki Prefecture, southern Japan, for antibodies against Japanese encephalitis virus (JEV). Strongylus vulgaris infection with severe arterial lesions and hemomelasma ilei was present in all necropsied horses. We frequently found intestinal ulcers, perihepatitis filamentosa, and poor body condition. We recorded degenerative arthropathy in metacarpophalangeal joints in two cases and a fracture of the rib with diaphragmatic rupture in one case. A total of 73% (177/242) of horses were seropositive for JEV as tested by hemagglutination inhibition (HI). The HI data also revealed that 74% (59/80) of the wild boars, 67% (60/90) of the pigs, and 29% (22/75) of the wild monkeys were seropositive for JEV. Our findings showed that Strongylus spp. are still a risk to horses in this region, and that environmental factors such as topographic location of the pasture and steep slope may have caused of degenerative arthropathy and bone fracture. Our results showed that JEV is endemic in Japan. The wild boars and pigs were presumed to act as strong amplifiers and sources of infection, with subsequent risk to humans.
DOI： 10.7589/2018-10-265
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Experimental induction of chicken amyloid A amyloidosis in white layer chickens by inoculation with inactivated vaccines.
Habibi WA, Hirai T, Niazmand MH, Okumura N, Yamaguchi R
Avian pathology : journal of the W.V.P.A 46 ( 5 ) 1 - 9 2017.5
Language：Japanese Publishing type：Research paper (scientific journal)
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Enhanced detection of Porcine reproductive and respiratory syndrome virus in fixed tissues by in situ hybridization following tyramide signal amplification.
Trang NT, Hirai T, Ngan PH, Lan NT, Fuke N, Toyama K, Yamamoto T, Yamaguchi R
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 27 ( 3 ) 326 - 31 2015.5
Language：Japanese Publishing type：Research paper (scientific journal)
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Membranoproliferative glomerulonephritis in a calf with nephrotic syndrome. Reviewed
Trang NT, Hirai T, Nabeta R, Fuke N, Yamaguchi R
Journal of comparative pathology 151 ( 2-3 ) 162 - 5 2014.8
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
A 2-month-old Japanese black calf was presented with a history of weight loss, exophthalmos and subcutaneous oedema of the brisket. Urinalysis and serum biochemistry showed proteinuria and hypoproteinaemia suggestive of nephrotic syndrome. Microscopically, lesions in the kidney were characterized by proliferation of mesangial cells and diffuse thickening of the glomerular basement membranes with the appearance of double contours. Immune complex deposits were confirmed by electron microscopy and immunofluorescence using reagents specific for bovine immunoglobulin G, complement factor C3 and bovine viral diarrhoea virus (BVDV). Consequently, the glomerular lesion in this case was diagnosed as membranoproliferative glomerulonephritis. BVDV type 1 was detected in serum by nested reverse transcriptase polymerase chain reaction. Viral antigen was also identified in the glomeruli by immunofluorescence. These results suggest that BVDV may have been the cause of immune complex glomerulonephritis in this calf. © 2014 Elsevier Ltd.
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Detection of porcine reproductive and respiratory syndrome virus in oral fluid from naturally infected pigs in a breeding herd.
Trang NT, Hirai T, Yamamoto T, Matsuda M, Okumura N, Giang NT, Lan NT, Yamaguchi R
Journal of veterinary science 15 ( 3 ) 361 - 7 2014
Language：Japanese Publishing type：Research paper (scientific journal)
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Mekata H., Yamada K., Umeki K., Yamamoto M., Ochi A., Umekita K., Kobayashi I., Hirai T., Okabayashi T.
BMC Veterinary Research 20 ( 1 ) 2024.12
Publishing type：Research paper (scientific journal) Publisher：BMC Veterinary Research
Severe fever with thrombocytopenia syndrome (SFTS) is a fatal zoonosis caused by ticks in East Asia. As SFTS virus (SFTSV) is maintained between wildlife and ticks, seroepidemiological studies in wildlife are important to understand the behavior of SFTSV in the environment. Miyazaki Prefecture, Japan, is an SFTS-endemic area, and approximately 100 feral horses, called Misaki horses (Equus caballus), inhabit Cape Toi in Miyazaki Prefecture. While these animals are managed in a wild-like manner, their ages are ascertainable due to individual identification. In the present study, we conducted a seroepidemiological survey of SFTSV in Misaki horses between 2015 and 2023. This study aimed to understand SFTSV infection in horses and its transmission to wildlife. A total of 707 samples from 180 feral horses were used to determine the seroprevalence of SFTSV using enzyme-linked immunosorbent assay (ELISA). Neutralization testing was performed on 118 samples. In addition, SFTS viral RNA was detected in ticks from Cape Toi and feral horses. The overall seroprevalence between 2015 and 2023 was 78.5% (555/707). The lowest seroprevalence was 55% (44/80) in 2016 and the highest was 92% (76/83) in 2018. Seroprevalence was significantly affected by age, with 11% (8/71) in those less than one year of age and 96.7% (435/450) in those four years of age and older (p < 0.0001). The concordance between ELISA and neutralization test results was 88.9% (105/118). SFTS viral RNA was not detected in ticks (n = 516) or feral horses. This study demonstrated that horses can be infected with SFTSV and that age is a significant factor in seroprevalence in wildlife. This study provides insights into SFTSV infection not only in horses but also in wildlife in SFTS-endemic areas.
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Hepatocellular carcinoma with lung metastasis showing hemochromatosis in an Egyptian fruit bat (Rousettus aegyptiacus). Reviewed
Kawaguchi N, Fuke N, Nueangphuet P, Pornthummawat A, Niazi AM, Izzati UZ, Hirai T, Yamaguchi R.
J Vet Med Sci. 10 ( 86 ) 49 - 53 2024.1
Language：English Publishing type：Research paper (scientific journal)
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Tanaka Y.L., Shofa M., Butlertanaka E.P., Niazi A.M., Hirai T., Mekata H., Saito A.
Pathogens 13 ( 1 ) 2024.1
Publishing type：Research paper (scientific journal) Publisher：Pathogens
Pigs are important animals for meat production but can carry several zoonotic diseases, including the Japanese encephalitis virus, Nipah virus, and influenza viruses. Several Orthomyxoviridae and Coronavirinae respiratory viruses require cleavage of envelope proteins to acquire viral infectivity and consequently, need a host protease or the addition of exogenous trypsin for efficient propagation. Host TMPRSS2 is a key protease responsible for viral cleavage. Stable expression of human TMPRSS2 in African green monkey-derived Vero cells can enhance the porcine epidemic diarrhea virus. However, considering the narrow host tropism of viruses, a porcine cell line expressing pig TMPRSS2 could be optimal for replicating pig-derived viruses. Herein, we generated and evaluated a pig-derived PK-15 cell line stably expressing pig TMPRSS2. This cell line markedly (>1000-fold) and specifically enhanced the growth of influenza viruses. Furthermore, we demonstrated the usefulness of a PK-15 cell line lacking the Stat2 gene with a stable expression of pig TMPRSS2 for efficient virus isolation from clinical samples in the presence of type I interferons. Therefore, PK-15 cells expressing pig TMPRSS2 could be a valuable and promising tool for virus isolation, vaccine production, and virological studies of TMPRSS2-dependent viruses.
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A case of hydronephrosis due to intrarenal ureteral obstruction in a Japanese Black calf Reviewed
Sato R., Hirai T., Hegazy A.A., Nakai M., Sato Y., Yamada K., Satoh H., Steiner A.
Journal of Veterinary Medical Science 86 ( 11 ) 1162 - 1167 2024
Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
A 23-day-old Japanese Black female calf presented with distension of the lower abdomen. Abdominal ultrasonography revealed a cystic structure with fluid accumulation and moderate echoluminance in the right abdominal cavity. Ultrasonography and contrast-enhanced computed tomography revealed congenital hydronephrosis due to narrowing of the intrarenal ureter, and right kidney resection was performed. Blood urea nitrogen and serum creatinine levels, which were within reference values preoperatively, peaked on the third postoperative day and gradually decreased afterward until reaching preoperative values on the tenth day. In bovine hydronephrosis, nephrectomy may provide a favorable prognosis if one kidney is intact. Moreover, this case suggests that blood tests immediately after surgery are not suitable for evaluating residual kidneys.
DOI： 10.1292/jvms.24-0173
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Surgical management of a dermoid cyst with mandibular gland tissue in a Japanese Black calf. Reviewed
Sato R, Sonoda M, Matsuo R, Takada R, Kanda I, Satoh H, Fuke N, Yamada K, Hirai T.
J Vet Med Sci. 19 ( 85 ) 1110 - 1115 2023.10
Language：English Publishing type：Research paper (scientific journal)
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Suwanruengsri M., Uemura R., Izzati U.Z., Kanda T., Fuke N., Yasuda M., Hirai T., Yamaguchi R.
Thai Journal of Veterinary Medicine 52 ( 1 ) 33 - 44 2022.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Thai Journal of Veterinary Medicine
Mycoplasma bovis (M. bovis) is a pathogen that especially effects the respiratory system of cattle. We focused on the histopathological changes in the lungs caused by M. bovis because the lesions in the bronchi or bronchioles and alveoli are quite different in natural infections. Thirty-five lung samples from 2-to 12-month-old Japanese Black calves with respiratory symptoms were collected and examined for bacteria presence and pathological changes using immunohistochemistry (IHC). Using the loop-mediated isothermal amplification method, 18 of the 35 samples were found to be positive for M. bovis, which was isolated and identified. In 7 of the samples, only M. bovis was detected, whereas in the other 11, other bacteria coexisted with M. bovis. Anti-M. bovis, anti-MAC387, anti-Iba1, anti-CD3, anti-CD20, anti-AE1/AE3 cytokeratin and anti-IL8 were used for antigen detection. Histopathological studies and diagnoses of the lungs were examined in two parts; bronchiolar lesions and alveolar lesions. The bronchiolar findings were divided into three groups: granulomatous, caseonecrotic and suppurative bronchiolitis. The alveolar lesions found were quite mild, except in three cases. IHC staining revealed strong evidence of M. bovis in degenerated neutrophils, which was confirmed by electron microscopy. The main inflammatory cell response to M. bovis infections was degenerate neutrophils, which caused the destruction of the bronchial epithelium and possibly induced epithelioid granulomatous inflammation, resulting in severe chronic respiratory diseases in cattle.
DOI： 10.14456/tjvm.2022.4
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Nueangphuet P., Tanabe M., Izzati U.Z., Fuke N., Hirai T., Yamaguchi R.
Journal of Veterinary Diagnostic Investigation 34 ( 1 ) 102 - 106 2022.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Diagnostic Investigation
A 14-y-old Miniature Pinscher bitch was admitted to a veterinary clinic because of inappetence and a distended abdomen; ultrasound examination revealed a fluid-filled uterus with a single 1-cm hyperechoic nodule in its lumen. Ovariohysterectomy was performed. Grossly, the uterine horns were distended irregularly and asymmetrically, and the uterine lumen contained 200–300 mL of brown watery fluid. A single white polypoid 0.9-cm diameter nodule was present at the site of the distended uterine horn and arose from the endometrium with a narrow stalk. Histologically, the polyp consisted of dense, smooth muscle fascicles admixed with glandular components; its surface was covered by simple cuboidal epithelium with areas of squamous metaplasia. The myomatous cells expressed the myogenic markers smooth muscle actin and desmin. We interpreted the mass as an adenomyomatous uterine polyp, which is a rare variant of an endometrial polyp.
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Suwanruengsri M., Uemura R., Kanda T., Fuke N., Nueangphuet P., Pornthummawat A., Yasuda M., Hirai T., Yamaguchi R.
Journal of Veterinary Diagnostic Investigation 34 ( 1 ) 68 - 76 2022.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Diagnostic Investigation
Mycoplasma bovis, the most important primary pathogen in the family Mycoplasmataceae, causes pneumonia, arthritis, otitis media, and mastitis in cattle. Histopathologic pulmonary changes associated with M. bovis infection have been characterized as suppurative-to-caseonecrotic bronchopneumonia; infection in other organs has been reported in only a few studies that examined caseonecrotic endocarditis and suppurative meningitis. Granulomatous lesions associated with M. bovis infection have been reported only rarely. We studied the granulomatous inflammation associated with M. bovis infection in several organs of 21 Japanese Black cattle. M. bovis was detected by isolation and loop-mediated isothermal amplification methods; other bacteria were detected using culture on 5% blood sheep agar and a MALDI-TOF MS Biotyper. Tissues were examined by histopathology and by immunohistochemistry (IHC) using anti–M. bovis, anti-Iba1, anti-iNOS, and anti-CD204 antibodies. All 21 cases, which included 2 cases of meningitis-meningoencephalitis, 8 cases of endocarditis, and 11 cases of bronchopneumonia, had caseonecrotic granulomatous inflammation associated with M. bovis infection. The IHC for macrophages revealed a predominance of iNOS-labeled (M1) macrophages in the inner layer of the caseonecrotic granulomas associated with meningitis-meningoencephalitis, endocarditis, and bronchopneumonia in Japanese Black cattle naturally infected with M. bovis.
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Toyama K., Hirai T., Sueyoshi M., Zhou Z., Niazi A.M., Kawaguchi N., Fuke N., Yamaguchi R.
Journal of Veterinary Medical Science 84 ( 11 ) 1536 - 1542 2022
Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Porcine circovirus 2 (PCV2) causes porcine circovirus-associated disease, and co-infection with porcine reproductive and respiratory syndrome virus (PRRSV) severely affects the pig breeding industry. Both viruses target the macrophages in lymphoid tissues. Various porcine pathogens enter via the nasal cavity, and the nasopharynx-associated lymphoid tissue (NALT) acts as the mucosal immune system. However, the pathological analysis has not progressed. This study aimed to histologically examine the NALT of pigs with suspected PCV2 and PRRSV infections. Six pigs were subjected to necropsy, and their NALT, tonsils, and mesenteric lymph nodes were collected. Macrophages, lymphocytic depletion, multinucleated giant cells, intracytoplasmic inclusion bodies, and neutrophil infiltration increased in the NALT. In situ hybridization revealed positive signals for PCV2 in the NALT of all pigs and PRRSV in the NALT of three pigs. PCV2-positive macrophages were mainly identified in the follicles, whereas PRRSV-positive tissues were found primarily around the crypt and directly below the epithelium. Quantitative PCR revealed 108 –1010 copies of PCV2 DNA/µL and 102 –104 copies of PRRSV DNA/µL in the NALT. Therefore, both PCV2 and PRRSV were detected in the NALT of pigs. In conclusion, the infection and replication of both viruses in the NALT and tonsils may suppress host immunity and promote co-infection with other pathogens.
DOI： 10.1292/jvms.22-0231
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Myint O., Hoa N.T., Fuke N., Pornthummawat A., Lan N.T., Hirai T., Yoshida A., Yamaguchi R.
BMC Veterinary Research 17 ( 1 ) 2021.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：BMC Veterinary Research
Background: Porcine epidemic diarrhoea (PED) is a highly contagious infectious disease with negative economic impacts on the swine industry. PED outbreaks were reported from 2009 to 2015, but sporadic infection has been observed until now in Vietnam. However, the seroprevalence of PEDV infection has not yet been reported for commercial pig farms in Vietnam. The aim of this study was to assess the seroprevalence of PEDV infection in Vietnamese pig farms to reveal the endemic status of PEDV in northern Vietnam. Results: A serological survey of PEDV infection was carried out using indirect ELISA in commercial pig farms in Hai Duong, Hung Yen and Thai Binh provinces in northern Vietnam in 2019. Twenty sera were randomly collected from each of 10 commercial pig farms, from each province; none of the farms had vaccinated for PEDV. Serological evidence of natural PEDV infection, expressed as a high antibody titre, was observed in the pig farms in all 3 provinces. The OD values were significantly higher (p < 0.001) for pig sera from Thai Binh than from Hai Duong and Hung Yen. No significant differences (p > 0.05) were detected for seropositivity to PEDV based on locality, age, pig breed and farm size. Conclusions: This study indicates serological evidence of natural PEDV infection with high antibody titre in commercial pig farms. PEDV infection was widespread among the pig population in these 3 provinces and that good management and strict biosecurity are needed at these pig farms.
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Nueangphuet P., Suwanruengsri M., Fuke N., Uemura R., Hirai T., Yamaguchi R.
Journal of Comparative Pathology 189 31 - 44 2021.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
Mycoplasma hyopneumoniae (Mhp) is the primary pathogen of porcine enzootic pneumonia (PEP). Consolidated lung tissue from the cranioventral lung lobes of 15 pigs with PEP was collected for quantitative polymerase chain reaction, histopathology and immunohistochemistry. Histopathology revealed the co-existence of bronchial-associated lymphoid tissue hyperplasia with intra-alveolar neutrophils and macrophage infiltration in lesions of suppurative bronchopneumonia. Immunolabelling of infiltrated macrophages with CD163/CD204 indicated the presence of M2-polarized macrophages. Mhp antigen was detected on respiratory epithelial cells and in phagocytosed neutrophils. The intensity of Mhp immunolabelling and number of CD163/CD204-positive macrophages were correlated with the Mhp load in lung tissue (r = 0.87, 0.56, P <0.05). IL-8 immunolabelling was mainly found in neutrophils and correlated with Mhp load, Mhp immunolabelling and histological lesion score (r = 0.70, 0.66, 0.64, P <0.05), respectively. Apoptosis was seen in intra-alveolar cells and was correlated with Mhp load (r = 0.62, P <0.05). It is postulated that IL-8 attracts neutrophils to the lesions, while M2-polarized macrophages are a major source of IL-10 and promote a Th2-type immune response.
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Izzati U.Z., Kaneko Y., Kaneko C., Yoshida A., Suwanruengsri M., Okabayashi T., Hirai T., Yamaguchi R.
Journal of Comparative Pathology 188 44 - 51 2021.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
Following isolation of pseudorabies virus (PRV) from two hunting dogs in Oita prefecture, Japan, we investigated the PRV antigen distribution in the tissues of the infected animals. At necropsy, PRV-associated lesions included facial oedema, tonsillar and meningeal congestion, blotchy haemorrhages on the pericardium and mitral valves, and incomplete splenic contraction in one dog, with less prominent findings in the other dog. Multiple pulmonary nodules were seen in both cases, caused by the diploid form of Paragonimus westermani lung flukes, as confirmed by PCR-restriction fragment length polymorphism and gene sequencing analyses. Histological examination revealed that the PRV infection was associated with lesions of non-suppurative encephalitis in the brainstem. PRV antigen was detected in the cerebrum, cerebellum, brainstem, submucosal and myenteric plexuses, and mononuclear cells, mainly in the bone marrow, lymph nodes, tonsils and spleen tissues. There was evidence of PRV dissemination to the brain via the trigeminal or olfactory routes, in addition to possible spread to lymphoid organs via infected mononuclear cells.
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Mycoplasma bovis May Travel Along the Eustachian Tube to Cause Meningitis in Japanese Black Cattle Reviewed
Suwanruengsri M., Uemura R., Izzati U.Z., Kanda T., Fuke N., Yasuda M., Hirai T., Yamaguchi R.
Journal of Comparative Pathology 188 13 - 20 2021.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
Mycoplasma bovis (M. bovis) is a common inhabitant of the upper and lower respiratory tracts of cattle and is considered to be the main aetiological agent of otitis media in calves. The eustachian tube appears to be the most common portal for pathogens to enter the middle ear. We investigated the transmission route of M. bovis causing otitis media that progressed to meningitis or meningoencephalitis in Japanese Black cattle. M. bovis was detected in 10 cases by a loop-mediated isothermal amplification method or by immunohistochemistry. One case of caseonecrotic granulomatous meningoencephalitis, one case of caseonecrotic granulomatous meningitis, one case of suppurative meningoencephalitis, eight cases of eustachitis, nine cases of tonsillitis and six cases of suppurative bronchopneumonia were identified by histopathological examination. M. bovis antigen was detected in the eustachian tubes of eight cases. In nine cases, M. bovis was also detected in tonsillar epithelial crypts and lumina, in intraluminal inflammatory cells and in the epithelial cells of minor salivary glands located around the eustachian tubes and tonsils. The results suggest that M. bovis can infect and colonize the tonsils and enter the eustachian tubes, causing otitis media, which, in cases of chronic infection, can progress to meningitis.
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Teh A.P.P., Kitahara G., Izzati U.Z., Mori K., Fuke N., Hirai T., Yamaguchi R.
Journal of Comparative Pathology 187 40 - 51 2021.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
Granulosa cell tumours (GCTs) are the most common type of bovine ovarian neoplasm. We describe the morphological and immunohistochemical features of GCTs (n = 26) and a thecoma (n = 1) using antibodies to cytokeratin AE1/AE3, vimentin, desmin, nectin-4, anti-Müllerian hormone (AMH), inhibin α, c-erbB-2 oncoprotein and proliferating cell nuclear antigen. The results indicate that, based on the expression similarity of AE1/AE3 and inhibin α, the macrofollicular growth pattern of GCTs derives from highly differentiated granulosa cells (GCs), the Graafian follicle or early atretic follicle. The trabecular growth pattern of GCTs is inferred to be derived from GCs of the atretic follicle in mature animals. AMH is a useful marker for diagnosing bovine sex cord-stromal tumours because it was expressed in all GCT cases and in the single case of thecoma.
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Bursa atrophy at 28 days old caused by variant infectious bursal disease virus has a negative economic impact on broiler farms in Japan Reviewed
Myint O, Suwanruengsri M, Araki K, Izzati UZ, Pornthummawat A, Nueangphuet P, Fuke N, Hirai T, Jackwood DJ, Yamaguchi R.
Avian Pathol 50 ( 1 ) 6 - 17 2021.2
Language：English Publishing type：Research paper (scientific journal)
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Suppurative necrotizing bronchopneumonia caused by Nocardia cyriacigeorgica infection in a stranded striped dolphin (Stenella coeruleoalba) in Japan. Reviewed
Ito S, Hirai T, Hamabe S, Subangkit M, Okabayashi T, Goto Y, Nishida S, Kurita T, Yamaguchi R.
J Vet Med Sci 21 ( 83 ) 146 - 150 2021.1
Language：English Publishing type：Research paper (scientific journal)
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Pathology of the outbreak of subgenotype 2.5 classical swine fever virus in northern Vietnam Reviewed
Izzati U.Z., Hoa N.T., Lan N.T., Diep N.V., Fuke N., Hirai T., Yamaguchi R.
Veterinary Medicine and Science 7 ( 1 ) 164 - 174 2021.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Veterinary Medicine and Science
Classical swine fever (CSF) is an endemic disease in southeastern Asia and is one of the most important swine diseases in Vietnam. This study was conducted to characterize the pathology of natural cases of CSF in northern Vietnam in 2018 and their genetic prevalence. A total of 10 representative pigs were collected from four provinces (Hung Yen, Ha Noi, Quang Ninh and Thai Binh) during five outbreaks and examined pathologically. The gross and histopathological findings showed the disease was expressed as the acute or the subacute to chronic form of CSF, depending on the age of the animals. The most consistently observed lesions associated with infection by the classical swine fever virus (CSFV) included lymphoid depletions in tonsils, lymph node and spleen; histiocytic hyperplasia in spleen; cerebral haemorrhage; perivascular cuffing in the brain; renal erythrodiapedesis; urothelial vacuolation and degeneration and interstitial pneumonia. The immunohistochemical findings showed a ubiquitous CSFV antigen mainly in the monocytes/macrophages and in the epithelial and endothelial cells in various organs. CSFV neurotropism was also found in the small neurons of the cerebrum and the ganglia of the myenteric plexus. Analysis of the full-length envelope protein (E2) genome sequence showed that all strains were genetically clustered into subgenotype 2.5, sharing a nucleotide identity of 94.0%–100.00%. Based on the results of this study, the strain was categorized as a moderately virulent CSFV.
DOI： 10.1002/vms3.339
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Myint O., Suwanruengsri M., Araki K., Izzati U.Z., Pornthummawat A., Nueangphuet P., Fuke N., Hirai T., Jackwood D.J., Yamaguchi R.
Avian Pathology 50 ( 1 ) 6 - 17 2021
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Avian Pathology
Infectious bursal disease (IBD), caused by IBD virus (IBDV), is highly contagious, immunosuppressive and causes a negative economic impact on poultry industry. IBDV-vaccinated broiler farms at south Kyushu, Japan had a bursa-to-bodyweight ratio (BB ratio) reduction at 28 days (d) old, followed by high mortality 30 d later. We analysed the influence of the IBDV on atrophy of the bursa of fabricius (BF) and the subsequent mortality after 30 d. Ten broilers were sampled at each timepoint from the farm with high mortality at 21, 25, 28 and 35 d. A second flock from the same farm was sampled at 14, 21, 25, 28, 35 and 42 d. IBDV was detected in BF samples at 25, 28 and 35 d and at 21, 25, 28 and 35 d in the first and second flocks, respectively, using immunohistochemical staining and RT-PCR. IBDV isolates from both flocks were closely related to the China KM523643 strain. Histopathology and TUNEL assay indicated apoptosis, severe lymphoid depletion, vacuoles within follicles, lymphoid follicle atrophy and fibrosis in the BF. We observed 75% of the polyserositis and 10% of the airsacculitis at 30 D in dead broilers. The antigenic variant IBDV infection was appeared to be the main influencing factor on BF atrophy and BB ratio reduction in the broilers. High mortality in the broilers after 30 d could be due to secondary infection. The disease caused by IBDV had a negative economic impact in the farm. RESEARCH HIGHLIGHTS New variant IBDV caused bursa atrophy and reduced BB ratio in 28-day-old broilers. After vIBDV had infected broilers, at 21 days old they became immunosuppressed. High mortality at 30 days old in broilers was due to secondary infection. New vIBDV has a negative economic impact on broiler farms in Japan.
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Pornthummawat A., Truong Q.L., Hoa N.T., Lan N.T., Izzati U.Z., Suwanruengsri M., Nueangphuet P., Hirai T., Yamaguchi R.
Journal of Veterinary Medical Science 83 ( 11 ) 1653 - 1660 2021
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Investigation of the role of animals that have recovered and survived from African swine fever (ASF) in carrying the ASF virus is currently intense and ongoing. However, no clear definition of the carrier stage has been established. The aim of the present study was to establish criteria to elucidate a clear status of survival in naturally ASF-infected domestic pigs in Vietnam. Seroconversion from previous infection was confirmed by serological assay, and the absence of the viral genome in various organs was also assured by molecular analysis of a partial p72 gene. We recognized that histopathological evidence could benefit from further insights into the status and role of the surviving animals; therefore, we performed a histopathological study on four pigs from farms with a history of ASF outbreak. We found fibrotic changes in the reparative process as the main finding in all four pigs. Immunohistochemical detection of viral protein revealed an interesting result. Despite the negative result from viral genome detection, the p30 protein gave a positive signal in the tonsils, lung, and stomach. This raises the possibility of stress-induced viral reactivation in long-term survivors and the risk of further outbreaks from human handling of contaminated carcasses.
DOI： 10.1292/jvms.21-0409
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Severe Degenerative Changes in Cryptorchid Testes in Japanese Black Cattle Reviewed
Fuke N., Kitahara G., Ito S., Van Diep N., Ping Teh A.P., Izzati U.Z., Myint O., Hirai T., Torisu S., Kaneko Y., Sato H., Hidaka Y., Osawa T., Yamaguchi R.
Veterinary Pathology 57 ( 3 ) 418 - 426 2020.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Veterinary Pathology
This is a histopathologic and endocrinologic study of 6 calves diagnosed with cryptorchidism. Cases 1–3 were diagnosed as resembling testicular regression syndrome. In cases 1 and 2, the extracted tissue was a small, firm, gray-white mass, and there was lack of obvious testicular tissue in case 3. Histopathologically, the excised tissue in cases 1–3 was a fibrotic testicular remnant with inflammation, mineralization, hemosiderin-laden macrophages or lipofuscin-laden macrophages, and lack of germ cells and interstitial endocrine cells. These findings were compared with cases 4–6, which were diagnosed as testicular hypoplasia due to cryptorchidism. These cases had small but otherwise grossly unremarkable intra-abdominal testicular tissue and histologically had a few germ cells and sustentacular cells with arrested spermatogenesis and an increase in interstitial endocrine cells. Cases 1–3 had more severe degenerative changes compared with cases 4–6. In case 2, the average diameter of the seminiferous tubules was much smaller than in cases 4–6, and there were few tubule cross sections. Anti-Müllerian hormone (214 pg/ml) was detected in the plasma of case 2. Based on the macroscopic and histopathologic findings as well as endocrinologic profiles, the testicular degeneration in cases 1–3 was considered similar to that of testicular regression syndrome. In this condition, it is thought that a normally developing intra-abdominal testis undergoes degeneration due to heat or a vascular disorder such as torsion.
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Severe Degenerative Changes in Cryptorchid Testes in Japanese Black Cattle. Reviewed
Fuke N, Kitahara G, Ito S, Van Diep N, Ping Teh AP, Izzati UZ, Myint O, Hirai T, Torisu S, Kaneko Y, Sato H, Hidaka Y, Osawa T, Yamaguchi R.
Vet Pathol 57 ( 3 ) 418 - 426 2020.2
Language：English Publishing type：Research paper (scientific journal)
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Disseminated Pneumocystosis in a Toy Poodle. Reviewed
Sakashita T, Kaneko Y, Izzati UZ, Hirai T, Fuke N, Torisu S, Yamaguchi R.
J Comp Pathol. 175 85 - 89 2020.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
A 1-year and 7-months-old neutered male toy poodle was presented with persistent respiratory distress, gradual weight loss and melaena. Thoracic radiography showed an unstructured interstitial lung pattern. Histopathological examination of tissues collected at necropsy examination revealed disseminated infection by Pneumocystis carinii. The organisms were detected in the lungs, lymph nodes, liver, heart, kidneys, spleen, gastrointestinal tract and pancreas. In the lungs, the organisms were present in the alveolar space and interstitial tissue, and calcified foci containing P. carinii were observed. The presence of the organism in non-thoracic lymph nodes provided evidence of lymphogenous spread. A definitive diagnosis of disseminated pneumocystosis was achieved through the use of Grocott methenamine silver staining, immunohistochemistry (IHC) and polymerase chain reaction for P. carinii. Depletion of cells expressing immunoglobulin (Ig)A and IgG was confirmed by IHC of lymphoid tissue, suggesting possible underlying immunodeficiency.
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Pathological investigation and viral antigen distribution of emerging African swine fever in Vietnam Reviewed
Izzati U.Z., Inanaga M., Hoa N.T., Nueangphuet P., Myint O., Truong Q.L., Lan N.T., Norimine J., Hirai T., Yamaguchi R.
Transboundary and Emerging Diseases 68 ( 4 ) 2039 - 2050 2020
Language：English Publishing type：Research paper (scientific journal) Publisher：Transboundary and Emerging Diseases
African swine fever (ASF) is emerging in Vietnam and poses a continuing severe threat to the swine industry. A histopathological study of clinical samples collected during the May to July 2019 outbreak of ASF was performed to determine the characteristic lesions. We analysed samples from eight ASFV-infected farms. Histopathological results revealed the characteristic lesions of the acute to the subacute clinical form of ASF. Immunohistochemical results showed ASFV viral antigen distribution in mononuclear cells/macrophage in various organs, hepatocytes and renal tubular epithelium. Molecular analysis of partial capsid protein 72 gene revealed that ASFV strain from the eight separate outbreaks belonged to genotype II.
DOI： 10.1111/tbed.13851
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Myint O., Yoshida A., Sekiguchi S., Van Diep N., Fuke N., Izzati U.Z., Hirai T., Yamaguchi R.
BMC Veterinary Research 15 ( 1 ) 2019.11
Language：English Publishing type：Research paper (scientific journal) Publisher：BMC Veterinary Research
Background: Porcine epidemic diarrhea virus (PEDV) infection is a highly contagious infectious disease causing watery diarrhea, vomiting, dehydration and high mortality rate in newborn piglets. PEDV infection can cause high economic losses in pig industry. In Japan, a PEDV outbreak occurred with high mortality from 2013 to 2015. Even though until now, PEDV infection occurs sporadically. For the control and monitoring of PEDV infection, not only symptomatic pigs, but also asymptomatic pigs should be identified. The objective of this study is to develop and optimize novel indirect ELISA as a simple, rapid, sensitive and specific method for the detection of anti-PEDV antibodies and evaluate the efficacy of the assay as a diagnostic method for PED. Results: One hundred sixty-two serum samples, consisting of 81 neutralization test (NT) positive and 81 NT negative sera, were applied to the assay. Indirect ELISA test based on whole virus antigen (NK94P6 strain) derived from Vero cell culture was evaluated by receiver operating characteristic (ROC) analysis with neutralization test (NT) as a reference method, and cut-off value was determined as 0.320 with sensitivity and specificity of 92.6 and 90.1%, respectively. The area under curve (AUC) was 0.949, indicating excellent accuracy of indirect ELISA test. There was significant positive correlation between indirect ELISA and neutralization test (R = 0.815, P < 0.05). Furthermore, the kappa statics showed the excellent agreement between these two tests (kappa value = 0.815). In addition, the sensitivity and specificity of preserved plates with different periods (1 day, 2 weeks, 1, 2, 3, 4, 5 and 6 months) after drying antigen coated plates were 100% and 80-100%, respectively. Conclusions: The developed indirect ELISA test in our study would be useful as a reliable test for serological survey and disease control of PEDV infection, and our pre-antigen coated ELISA plates can be preserved at 4 °C until at least 6 months.
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Ameloblastic Carcinoma Arising from an Amyloid-Producing Odontogenic Tumour in a Reviewed
Izzati UZ, Hidaka Y, Hirai T, Yamaguchi R.
J Comp Pathol 166 54 - 58 2019.1
Language：English Publishing type：Research paper (scientific journal)
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Teh A., Hirai T., Ito S., Hidaka Y., Goto Y., Furukawa H., Sawada J., Yamaguchi R.
Medical Mycology Case Reports 21 37 - 40 2018.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Medical Mycology Case Reports
A 7-month-old female Japanese Black calf developed elongated, nodular mass measuring 30 × 16 cm extended from the retropharyngeal region to mid lateral neck region. Histological examination revealed granulomatous lymphangitis with non-septate fungal hyphae recognized throughout the lesions. Fungal culture, DNA sequencing and molecular phylogenetic tree analysis confirmed the sequence of Lichtheimia corymbifera. The lymphogenous route was speculated to be the main route of fungal spread leading to the characteristic nodular appearance of this case.
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Local extensive granulomatous inflammation of the neck region and lymphangitis Reviewed
Teh APP, Hirai T, Ito S, Hidaka Y, Goto Y, Furukawa H, Sawada J, Yamaguchi R.
Med Mycol Case Rep 17 ( 21 ) 37 - 40 2018.4
Language：English Publishing type：Research paper (scientific journal)
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Van Diep N., Sueyoshi M., Norimine J., Hirai T., Myint O., Teh A.P.P., Izzati U.Z., Fuke N., Yamaguchi R.
BMC Veterinary Research 14 ( 1 ) 2018.3
Language：English Publishing type：Research paper (scientific journal) Publisher：BMC Veterinary Research
Background: Since late 2013, porcine epidemic diarrhea virus (PEDV) has reemerged in Japan and caused severe economic losses to the swine industry. Although PEDV vaccines have been used widely, the disease has swept rapidly across the county, and is commonly observed in PED-vaccinated farms, and has recurred in domestic herds. To better understand PEDVs responsible for the reemerging outbreaks in Japan, full-length spike (S), membrane (M), and nucleocapsid (N) genes of 45 PEDVs collected in Japan during 2013-2016, were sequenced and analyzed. Results: Phylogenetic analysis based on S gene sequences revealed that all the recent field PEDVs were genetically distinct from the classical Japanese strains, and were classified into three genotypes: North American (NA), S INDEL, and Asian non-S INDEL. Our data suggested a possibility that multiple parental PEDV strains were introduced into Japan from abroad at the same time or similar times. The newly identified Japanese strains showed the closest relationship to the US strains. Two sublineages of Japanese strains circulating in Japan were similar to two sublineages identified in the US, suggesting common ancestors for these strains. In comparison with two vaccine strains used in Japan, the field strains had various changes in epitope regions, glycosylation sites, and phosphorylation sites. These substitutions, particularly observed in epitope regions of the S (521, 553, 568, and 570), M (5), and N (123, 252, and 255) proteins, may have affected antigenicity and vaccine efficacy, resulting in an unsuccessful PEDV control. Sequence comparisons between PEDVs collected from primary and secondary outbreaks in three herds revealed that the disease has developed to an endemic stage in which PEDV could persist for nearly two years in the herds or local regions, causing subsequent epidemics. Conclusions: These results elucidate the genetic characteristics, origin, and molecular epidemiology of PEDVs circulating in Japan, as well as the PEDV strains causing recurrent outbreaks. This study provides a better insight into the PEDVs responsible for recent outbreaks in Japan, and could potentially help to develop measures for controlling and preventing the disease.
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Appearance of US-like porcine epidemic diarrhoea virus (PEDV) strains before US outbreaks and genetic heterogeneity of PEDVs collected in Northern Vietnam during 2012-2015. Reviewed
Diep NV, Sueyoshi M, Izzati U, Fuke N, Teh APP, Lan NT, Yamaguchi R
Transboundary and emerging diseases 65 ( 1 ) e83 - e93 2018.2
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Merkel Cell Carcinoma in a Steer Reviewed
Teh A.P.P., Izzati U.Z., Diep N.V., Hirai T., Yamaguchi R.
Journal of Comparative Pathology 158 17 - 21 2018.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
Merkel cell carcinoma is a rare and aggressive cutaneous neuroendocrine tumour reported only in man, dogs and cats. A 20-month-old Japanese black fattening steer was presented with necrotic protruding skin masses over the left thoracic area and a 20 × 25 cm subcutaneous mass in the left abdominal area. Microscopical evaluation of the masses revealed cords of small to medium-sized round tumour cells with marked anisocytosis and anisokaryosis and clear and vacuolated cytoplasm, which were separated by a delicate fibrovascular stroma and arranged in a trabecular and nested pattern. Necropsy examination revealed multiple solid white nodular masses in the lungs. Immunohistochemistry (IHC) for cytokeratin (CK) 20 and CKAE1/3 revealed focal perinuclear labelling of tumour cells. IHC for the neuroendocrine markers chromogranin A and neuron specific enolase, the neuroepithelial stem cell marker nestin and the hormonal markers adrenocorticotropic hormone and calcitonin revealed diffuse cytoplasmic labelling of all tumour cells. Ultrastructurally, the tumour cells contained few neurosecretory granules and abundant glycogen pools. The tumours were diagnosed as Merkel cell carcinoma with pulmonary metastases and this case represents the first such diagnosis in cattle.
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TEH Angeline Ping Ping, PRATAKPIRIYA Watanyoo, HIDAKA Yuichi, SATO Hiroyuki, HIRAI Takuya, YAMAGUCHI Ryoji
Journal of Veterinary Medical Science 79 ( 4 ) 714 - 718 2017.4
Language：English Publishing type：Research paper (scientific journal) Publisher：JAPANESE SOCIETY OF VETERINARY SCIENCE
DOI： 10.1292/jvms.16-0501
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Histopathological changes in the pancreas of cattle with abdominal fat necrosis
TANI Chikako, PRATAKPIRIYA Watanyoo, TANI Mineto, YAMAUCHI Takenori, HIRAI Takuya, YAMAGUCHI Ryoji, ANO Hitoshi, KATAMOTO Hiromu
Journal of Veterinary Medical Science 79 ( 1 ) 52 - 59 2017.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：JAPANESE SOCIETY OF VETERINARY SCIENCE
DOI： 10.1292/jvms.16-0282
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Hidaka Yuichi, Tsuzuki Nao, Hagio Mitsuyoshi, Koike Kouji, Misumi Shun, Kikkawa Lisa, Konishi Yuko, Satoh Hiroyuki, Hirai Takuya, Mido Shogo, Horii Yoichiro
Journal of Japan Veterinary Cancer Society 6 ( 1 ) 5 - 12 2017
Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Veterinary Cancer Society
Non-selective intra-arterial (I-A) chemotherapy of paclitaxel plus platinum combination was performed in two dogs with cancers of the nasal cavity, including undifferentiated (Case 1) and transitional (Case 2) carcinomas. The drug dosages were reduced to 25% to 35.5% of the typical doses for systemic chemotherapy, and they were perfused via common carotid arteries. Case 1 had marked regression of the cancer but survived for only 53 days after the therapy. Case 2 had partial remission for approximately 3 months and survived for 126 days. Adverse events of the chemotherapies were not induced in Case 1, but mild adverse events were seen in Case 2. Non-selective I-A chemotherapy in this report required easy and simple procedures and could be safely performed via a reduction of the dosages of the drugs. Although future research will address issues concerning the intervals, frequencies, and drug dosages, the I-A chemotherapy was suggested as being able to contribute to palliative remission in canine intranasal cancers.
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Non-tuberculous Mycobacteriosis with T-cell Lymphoma in a Red Panda (Ailurus fulgens). Reviewed
Fuke N, Hirai T, Makimura N, Goto Y, Habibi WA, Ito S, Trang NT, Koshino K, Takeda M, Yamaguchi R
Journal of comparative pathology 155 ( 2-3 ) 263 - 266 2016.8
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
A 9-year-old male red panda (Ailurus fulgens) became emaciated and died. Necropsy examination revealed systemic lymphadenomegaly. The liver, lungs and left kidney contained multifocal yellow nodules. Microscopical examination revealed granulomatous inflammation in the liver, lungs, kidney, spleen and lymph nodes, with numerous acid-fast bacilli. Sequencing of genetic material isolated from the tissues classified the pathogen as Mycobacterium gastri. Lymphoma was found in the liver, lungs, kidney and lymph nodes. The neoplastic cells were strongly labelled for expression of CD3, Ki67 and proliferating cell nuclear antigen by immunohistochemistry. This is the first report of M. gastri infection with T-cell lymphoma in a red panda.
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Non-tuberculous Mycobacteriosis with T-cell Lymphoma in a Red Panda (Ailurus fulgens). Reviewed
Fuke N, Hirai T, Makimura N, Goto Y, Habibi WA, Ito S, Trang NT, Koshino K,
J Comp Pathol. 155 263 - 266 2016.7
Language：English Publishing type：Research paper (scientific journal)
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Pathological Characterization of an Outbreak of Porcine Reproductive and Respiratory Syndrome in Northern Vietnam. Reviewed
Huong Giang NT, Lan NT, Nam NH, Hirai T, Yamaguchi R.
J Comp Pathol. 154 135 - 149 2016.6
Language：English Publishing type：Research paper (scientific journal)
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Huong Giang N.T., Lan N.T., Nam N.H., Hirai T., Yamaguchi R.
Journal of Comparative Pathology 154 ( 2-3 ) 135 - 149 2016.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Comparative Pathology
In 2007, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) emerged in Vietnam and spread to nearly all regions of the country by 2010. Ten representative pigs of different age groups, infected naturally with HP-PRRSV in northern Vietnam in 2010, were used to characterize the pathological features of the infection. Infection was confirmed using reverse transcriptase polymerase chain reaction and viral isolation. The clinical signs and gross findings in these pigs included high fever (>40.2°C), red skin, blue ears, anorexia, respiratory distress, diarrhoea, haemorrhagic pleurisy and lymphadenopathy. Reproductive failure was the main clinical feature in sows. PRRSV infection-associated microscopical lung and lymph node lesions were observed frequently, regardless of age of the animals. Lung lesions were characterized by interstitial pneumonia and were occasionally associated with haemorrhage and fluid exudation following alveolar collapse. Lymph nodes exhibited characteristic haemorrhage and apoptosis, lymphocytic depletion and disorganization secondary to fibrosis and capillary formation. Haematoxylin and eosin staining or caspase-3 immunohistochemistry revealed apoptosis induction in various tissues and organs, particularly the lymph nodes and lungs. Primarily haemorrhagic microscopical lesions were observed commonly in other organs including the spleen, liver, heart and kidney. Immunohistochemical examination revealed HP-PRRS antigen in the lung, lymph node, liver and kidney macrophages, and lung and kidney epithelial cells. Pigs infected naturally with HP-PRRS in the field have multisystemic disease characterized by marked apoptotic cell death.
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US-like isolates of porcine epidemic diarrhea virus from Japanese outbreaks between 2013 and 2014.
Van Diep N, Norimine J, Sueyoshi M, Lan NT, Hirai T, Yamaguchi R
SpringerPlus 4 756 2015
Language：Japanese Publishing type：Research paper (scientific journal)
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Membranoproliferative glomerulonephritis in a calf with nephrotic syndrome. Reviewed
Trang NT, Hirai T, Nabeta R, Fuke N, Yamaguchi R.
J Comp Pathol. 151 162 - 165 2014.7
Language：English Publishing type：Research paper (scientific journal)
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A Canine Case of Ovarian Carcinoma with Pulmonary Metastasis Treated with Surgery and Paclitaxel / Platinum Combination Chemotherapy. Reviewed
Hidaka Y., Kodama A., Tamura R., Ito M., Koike K., Hirai T., Satoh H. and Hagio M.
J. Jpn. Vet. Cancer. Soc. 5 ( 1 ) 6 - 11 2014.2
Language：English Publishing type：Research paper (scientific journal)
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Trang N.T., Hirai T., Yamamoto T., Matsuda M., Okumura N., Giang N.T.H., Lan N.T., Yamaguchi R.
Journal of Veterinary Science 15 ( 3 ) 361 - 367 2014
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Science
The objectives of the present study were to evaluate the anatomic localization of porcine reproductive and respiratory syndrome virus (PRRSV) in naturally infected pigs and to determine whether oral fluid could be used to detect the virus in infected animals. Two sows, seven 2-month-old grower pigs, and 70 6-month-old gilts were included in this study. PRRSV in sera and oral fluid were identified by nested reverse transcription PCR (nRT-PCR) while lung, tonsil, and tissue associated with oral cavity were subjected to nRT-PCR, immunohistochemistry, and in situ hybridization. In sows, PRRSV was identified in oral fluid and tonsils. PRRSV was also detected in oral fluid, tonsils, salivary glands, oral mucosa, and lungs of all seven grower pigs. However, viremia was observed in only two grower pigs. Double staining revealed that PRRSV was distributed in macrophages within and adjacent to the tonsillar crypt epithelium. In gilts, the North American type PRRSV field strain was detected 3 to 8 weeks after introducing these animals onto the farm. These results confirm previous findings that PRRSV primarily replicates in tonsils and is then shed into oral fluid. Therefore, oral fluid sampling may be effective for the surveillance of PRRSV in breeding herds.
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Hidaka Yuichi, Kodama Akihito, Tamura Ryota, Ito Masafumi, Koike Kouji, Hirai Takuya, Satoh Hiroyuki, Hagio Mitsuyoshi
Journal of Japan Veterinary Cancer Society 5 ( 1 ) 6 - 11 2014
Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Veterinary Cancer Society
A five-year-old female Miniature Dachshund was presented with abdominal distension and dyspnea. Physical, radiographical, and ultrasound examinations detected an abdominal mass and pleural effusion. The cytology of the mass and effusion indicated a malignant tumor, possibly of ovarian origin, with intrathoracic metastasis. Laparotomy demonstrated that the mass originated from the left ovary, and a complete ovariohysterectomy was performed. The histopathological examination revealed papillary adenocarcinoma in both ovaries. Paclitaxel/platinum combination chemotherapy was administered nine times to control pleural effusion, and the dog survived 623 days after the surgery. The postmortem examination confirmed that the metastatic tumor had spread to the lungs. Paclitaxel/platinum combination chemotherapy may be an acceptable option for treatment in dogs with metastatic ovarian adenocarcinoma.
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Antimicrobial resistance in Salmonella serovars isolated from meat shops at the markets in North Vietnam.
Thai TH, Lan NT, Hirai T, Yamaguchi R
Foodborne pathogens and disease 9 ( 11 ) 986 - 91 2012.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Pathological effects in lymphoid tissues of the spleen, lymph nodes, and Peyer's patches in cyclosporin-treated cynomolgus monkeys.
Moriyama A, Maeda H, Hirai T, Yamaguchi R
The Journal of veterinary medical science 74 ( 11 ) 1487 - 91 2012.11
Language：Japanese Publishing type：Research paper (scientific journal)
DOI： 10.1292/jvms.12-0155
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Nectin4 is an epithelial cell receptor for canine distemper virus and involved in neurovirulence.
Pratakpiriya W, Seki F, Otsuki N, Sakai K, Fukuhara H, Katamoto H, Hirai T, Maenaka K, Techangamsuwan S, Lan NT, Takeda M, Yamaguchi R
Journal of virology 86 ( 18 ) 10207 - 10 2012.9
Language：Japanese Publishing type：Research paper (scientific journal)
DOI： 10.1128/JVI.00824-12
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Antimicrobial resistance of Salmonella serovars isolated from beef at retail markets in the north Vietnam. Reviewed
Thai TH, Hirai T, Lan NT, Shimada A, Ngoc PT, Yamaguchi R
The Journal of veterinary medical science 74 ( 9 ) 1163 - 9 2012.9
Language：English Publishing type：Research paper (scientific journal)
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Thai T.H., Hirai T., Lan N.T., Shimada A., Ngoc P.T., Yamaguchi R.
Journal of Veterinary Medical Science 74 ( 9 ) 1163 - 1169 2012.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Approximately 39.9% (63/158) of beef samples collected from retail markets in Hanoi from January to June 2009 were Salmonella- positive. Nine Salmonella serovars, Anatum (28.6%), Rissen (25.4%), Weltevreden (12.7%), Typhimurium (7.9%), Derby (7.9%), Lexington (7.9%), Dublin (4.6%), Newport (3.2%) and London (1.8%), were identified. Thirty-seven (58.7%) of the 63 Salmonella isolates were resistant to at least one antimicrobial tested, of which 29 (46%) isolates showed multidrug resistance (MDR). The isolates were commonly resistant to tetracycline (46.0%), sulphonamide (39.7%), ampicilline (31.7%), streptomycin (30.2%), trimethoprim (28.6%), kanamycin (28.6%) and chloramphenicol (22.2%). Fourteen (bla , bla , aadA1, aadA2, sul1, tetA, tetB, tetG, cmlA1, floR, dfrA1, dfrA12, aac (3)-IV and aphA1-1AB) out of 22 antimicrobial resistance genes were detected by PCR from the resistant isolates. The catA1, Kn, bla genes and plasmid-mediated quinolones resistance (PMQR) genes such as qnrA, qnrB, qnrS, qepA and acc (6')-ib-cr were not detected. Mutations in the gyrA gene leading to the amino acid changes Ser83Phe and/or Asp87Asn were found in 6 out of the 11 quinolone-resistant isolates. The data revealed that multidrug resistant Salmonella strains were widely distributed in north Vietnam via the food chain and might contain multiple genes specifying identical resistant phenotypes. Thus, continuous studies are necessary to clarify the mechanisms of MDR in Salmonella and its spread in the livestock market. ©2012 The Japanese Society of Veterinary Science. TEM OXA-1 PSE-1
DOI： 10.1292/jvms.12-0053
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Antibiotic resistance profiles of Salmonella serovars isolated from retail pork and chicken meat in North Vietnam.
Thai TH, Hirai T, Lan NT, Yamaguchi R
International journal of food microbiology 156 ( 2 ) 147 - 51 2012.5
Language：Japanese Publishing type：Research paper (scientific journal)
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Quantitative analyses of lymphoid tissue in the spleen, lymph nodes and Peyer's patches in cynomolgus monkeys.
Moriyama A, Fujishima J, Furukawa T, Yoshikawa T, Kodama R, Sasaki Y, Nagaoka T, Kamimura Y, Maeda H, Hirai T, Yamaguchi R
The Journal of veterinary medical science 73 ( 11 ) 1459 - 64 2011.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Yamaguchi R., Moriyama A., Fujishima J., Furukawa T., Yoshikawa T., Kodama R., Sasaki Y., Nagaoka T., Kamimura Y., Maeda H., Hirai T.
Journal of Veterinary Medical Science 73 ( 11 ) 1459 - 1464 2011.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
To clarify the morphological characteristics of the cynomolgus monkey immune system, we analyzed quantitative data on their lymphoid organs. Spleens, major lymph nodes and Peyer's patches were sampled from cynomolgus monkeys, and the lymphoid follicle and germinal center areas and percentages of CD3- and CD20-positive areas were calculated. All the organs analyzed showed large inter-individual variations in the sizes of lymphoid follicles and germinal centers. Lymphoid follicle in the spleen, submandibular lymph nodes and Peyer's patches showed no marked difference in size. Germinal center size in the mesenteric lymph nodes and Peyer's patches were significantly smaller than those in the spleen. Areas containing T cells were largest in the lymph nodes, while those containing B cells were largest in the spleen and Peyer's patches. The mean size of the splenic lymphoid follicle in cynomolgus monkeys is larger than that in rats and similar to that in humans. Based on the large individual variation and the characteristics of lymphoid organs, it is important to use cynomolgus monkeys in standard toxicity studies. Taking advantage of the characteristics of each species enables reliable evaluation of the immunologic system in standard toxicity studies.
DOI： 10.1292/jvms.11-0207
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Hepatic myelolipoma with systemic amyloidosis in a goose (Anser cygnoides domesticus) Reviewed
Suzuki T., Uetsuka K., Kusanagi K., Hirai T., Nunoya T., Doi K.
Journal of Veterinary Medical Science 72 ( 5 ) 670 - 671 2010.6
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
We report here a case of hepatic myelolipoma with systemic amyloidosis in a goose (Anser cygnoides domesticus), which died suddenly following the short history of weakness and greenish diarrhea. At necropsy, multiple yellowish-white foci were observed on the surface of the prominently enlarged liver. Histologically, there were multiple foci of adipose tissue admixed with myeloid elements in various proportions in the liver as well as amyloid deposition in several organs including the liver, intestine, spleen, kidney, and ovary. Ultrastructurally, erythroblast-like cells and myelocytes, which showed various stages of differentiation, were observed in the foci of the liver. These findings shared characteristics of hepatic myelolipoma which is very rare in birds.
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Degeneration of the octavus nerve observed in a stranded Risso's dolphin (Grampus griseus), infested with Crassicauda grampicola Reviewed
T. Morimitsu, M. Koono, T. Hirai and T. Kurita
Japan Cetology 20 7 - 12 2010.6
Language：Japanese Publishing type：Research paper (scientific journal)
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Hepatic Myelolipoma with Systemic Amyloidosis in a Goose (Anser cygnoides Reviewed
Suzuki T, Uetsuka K, Kusanagi K, Hirai T, Nunoya T, Doi K.
J Vet Med Sci 72 ( 5 ) 669 - 671 2010.1
Language：English Publishing type：Research paper (scientific journal)
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Hepatic Myelolipoma with Systemic Amyloidosis in a Goose (<i>Anser cygnoides domesticus</i>) Reviewed
SUZUKI Takayuki, UETSUKA Kouji, KUSANAGI Kouichi, HIRAI Takuya, NUNOYA Tetsuo, DOI Kunio
Journal of Veterinary Medical Science 72 ( 5 ) 669 - 671 2010
Language：English Publishing type：Research paper (scientific journal) Publisher：JAPANESE SOCIETY OF VETERINARY SCIENCE
DOI： 10.1292/jvms.09-0457
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Multiplex PCR and multiplex RT-PCR for inclusive detection of major swine DNA and RNA viruses in pigs with multiple infections. Reviewed
Ogawa H, Taira O, Hirai T, Takeuchi H, Nagao A, Ishikawa Y, Tuchiya K, Nunoya T, Ueda S.
J Virol Methods 160 210 - 214 2009.9
Language：English Publishing type：Research paper (scientific journal)
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Ogawa H., Taira O., Hirai T., Takeuchi H., Nagao A., Ishikawa Y., Tuchiya K., Nunoya T., Ueda S.
Journal of Virological Methods 160 ( 1-2 ) 210 - 214 2009.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Virological Methods
Multiplex PCR and multiplex RT-PCR were developed to identify nine viruses in pigs with multiple infections. These viruses are: porcine circovirus type 2 (PCV2), suid herpesvirus 1, porcine parvovirus (PPV), porcine reproductive and respiratory syndrome virus (PRRSV), Japanese encephalitis virus, porcine rotavirus A (PoRV-A), porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and Getah virus. These methods were shown to be high specificity and sensitivity. In the clinical application, a total of 75 field samples were examined by our methods and previously reported methods for PCV2, PRRSV, TGEV, and PEDV. As a result, the detection rates of our multiplex PCR and multiplex RT-PCR were higher than those of the previously reported methods. Furthermore, it was confirmed that 24 PCV2 positive samples were co-infected with other viruses, 11 with PRRSV, 10 with PPV, 2 with PoRV-A, and 1 with TGEV by a combination of multiplex PCR and multiplex RT-PCR. PPV and PoRV-A were newly detected by multiplex PCR and multiplex RT-PCR. These results suggest that the combination of our multiplex PCR and multiplex RT-PCR is useful for rapid and accurate identification of nine major pathogenic viruses in pigs with multiple infections. © 2009 Elsevier B.V. All rights reserved.
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LAN Nguyen Thi, YAMAGUCHI Ryoji, HIRAI Takuya, KAI Kazushige, MORISHITA Kazuhiro
Journal of Veterinary Medical Science 71 ( 4 ) 457 - 461 2009.5
Language：English Publishing type：Research paper (scientific journal) Publisher：JAPANESE SOCIETY OF VETERINARY SCIENCE
DOI： 10.1292/jvms.71.457
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Relationship between growth behavior in vero cells and the molecular characteristics of recent isolated classified in the Asia 1 and 2 groups of canine distemper virus. Reviewed
Lan NT, Yamaguchi R, Hirai T, Kai K, Morishita K.
J Vet Med Sci 71 ( 4 ) 457 - 461 2009.4
Language：English Publishing type：Research paper (scientific journal)
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Lan N.T., Yamaguchi R., Kien T.T., Hirai T., Hidaka Y., Nam N.H.
Journal of Veterinary Medical Science 71 ( 2 ) 155 - 162 2009.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Canine distemper caused by canine distemper virus (CDV) is a contagious, incurable, often fatal, multisystemic viral disease that affects the respiratory gastrointestinal and central nervous system. Strains Vn86 and Vn99 of CDV were isolated, we believe for the first time, in Vietnam from two 4-month-old autopsied dogs pathologically showing non-suppurative encephalitis with pneumonia, lymphoid depletion and severe gastroenteritis. These strains caused syncytium cytopathic effect in Vero cells and Vero cells expressing canine signaling lymphocyte activation molecules. The titers of cell-associated viruses of both strains were higher than for released viruses. Molecular analysis showed that both new isolates of CDV joined to the group of classic type that is far from the Asia 1 and Asia 2 groups. These results indicated that first isolation and characterization of canine distemper virus in Vietnam with the immunohistochemical examination of the dog.
DOI： 10.1292/jvms.71.155
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First isolation and characterization of canine distemper virus in Vietnam with the immunohistochemical examination of the dog. Reviewed
Lan NT, Yamaguchi R, Kien TT, Hirai T, Hidaka Y, Nam NH.
J Vet Med Sci 71 ( 2 ) 155 - 162 2009.2
Language：English Publishing type：Research paper (scientific journal)
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Nakamura K., Shibuya K., Saito N., Shimada K., Ohshima A., Hirai T., Nunoya T.
Journal of Poultry Science 45 ( 4 ) 298 - 302 2008.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Poultry Science
Japanese quail (Cotumix coturnix japonica) is widely used in avian reproduction tests and avian sex reversal screening tests for evaluating adverse effects of endocrine disrupting chemicals (EDCs). However, there are few reports on the molecular biological profiles during the development and sexual differentiation of the gonads in Japanese quail. In the present study, we investigated mRNA expression of cytochrome P450 17αhydroxylase (P450c17), cytochrome P450 aromatase (P450 arom), anti-Mttllerian hormone (AMH), estrogen receptor α (ERα) and androgen receptor (AR) in the embryonic and post-hatching gonads of Japanese quail by using real-time RT-FCR. The left gonads of male and female Japanese quail at 16 days of incubation and 3, 7 and 14 days after hatching were used, in the study. P450c17 mRNA expression in females was significantly higher than that in males at 16 days of incubation, 3 and 7 days after hatching. P450arom mRNA expression in females was markedly higher than that in males and there were significant differences at 3, 7 and 14 days after hatching. AMH mRNA expression in males was apparently higher than that in females and there were significant differences at 16 days of incubation and 3 days after hatching. ERα mRNA was highly expressed not only in females but also in males at 16 days of incubation. There were no meaningful trends of AR mRNA expressions in male and female gonads during the observation periods. It is likely that the profiles of mRNA expression of P450c17, P450arom, AMH, ERα and AR in the embryonic and post-hatching gonads of normal Japanese quail in the present study provide basic and useful information. Copyright © 2008, Japan Poultry Science Association.
DOI： 10.2141/jpsa.45.298
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An undifferentiated sarcoma in a rat resembling extraskeletal myxoid chondrosarcoma in man.
Nakamura K, Shibuya K, Hirai T, Nunoya T.
Toxocol Pathol 35 ( 5 ) 672 - 675 2007.10
Language：English Publishing type：Research paper (scientific journal)
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An undifferentiated sarcoma in a rat resembling extraskeletal myxoid chondrosarcoma in man Reviewed
Nakamura K., Shibuya K., Hirai T., Nunoya T.
Toxicologic Pathology 35 ( 5 ) 672 - 675 2007.8
Language：English Publishing type：Research paper (scientific journal) Publisher：Toxicologic Pathology
A soft tissue tumor occurring in the inguinal subcutaneous tissue was detected in a 109-week-old male F344 rat. Macroscopically, the tumor mass showed no skeletal relationship and a gelatinous multinodular appearance. Histologically, the tumor consisted of irregular lobules separated by scant fibrous septa. In each lobule, tumor cells were arranged in cords and strands in the plentiful myxoid stroma. The tumor cells showed marked pleomorphism, and had large, round to ovoid nuclei and abundant eosinophilic cytoplasm. Mitotic figures were often seen. Myxoid stroma of the tumor contained a large amount of acid mucopolysaccharides and collagen type II, which were demonstrated by histochemistry and immunohistochemistry respectively. The tumor cells showed positive immunoreactivities for vimentin and S100 protein. Ultrastructural examination revealed that the tumor cells had a large amount of mitochondria, Golgi complex and dilated rough endoplasmic reticulum containing amorphous material, and the myxoid stroma contained collagenous fibrils and proteoglycan particles. Based on these results, the present tumor in a rat resembled extraskeletal myxoid chondrosarcoma in man. Copyright © by the Society of Toxicologic Pathology.
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Actinomycosis of the brain and temporal bone in a goat.
Hirai T, Nunoya T, Azuma R.
J Vet Med Sci 69 ( 6 ) 641 - 643 2007.6
Language：English Publishing type：Research paper (scientific journal)
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Actinomycosis of the brain and temporal bone in a goat Reviewed
Hirai T., Nunoya T., Azuma R.
Journal of Veterinary Medical Science 69 ( 6 ) 641 - 643 2007.6
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
A goat with neurologic signs had multifocal abscesses containing sulfur granules in the right brain and temporal bone. Histologically, the lesions consisted of pyogranulomas with several radiating bacterial colonies of various sizes. A tangled mass of filamentous and gram-positive bacteria was recognized in the central part of the colony. Actinomyces naeslundii antigen was detected in the colonies of bacteria in the brain and neighboring bone tissue by immunohistochemistry. Actinomycosis involving the central nervous system (CNS) and temporal bone is rare in animals. Cerebral infection with A. naeslundii may have resulted from direct extension from cervicofacial regions because the CNS lesions were distributed asymmetrically and were continuous with the right temporal bone.
DOI： 10.1292/jvms.69.641
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Use of miniature pig for biomedical research, with reference to toxicologic studies Reviewed
Tetsuo Nunoya, Kazumoto Shibuya, Toshiki Saitoh, Hajime Yazawa, Keigo Nakamura, Yasuko Baba, Takuya Hirai
J Toxicol Pathol 20 125 - 132 2007.5
Language：English Publishing type：Research paper (scientific journal)
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Koyama T., Hirai T., Nagai S.
Journal of Veterinary Medical Science 68 ( 6 ) 609 - 613 2006.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Lawsonia intracellularis isolated from a Japanese field case of porcine proliferative enteropathy (PPE) was cultivated and partially characterized. The bacterial cells isolated from the intestinal mucosa of a pig suffering from the acute form of PPE were used to inoculate rat small intestine cells (IEC-18) and human epithelial cells (HEp-2). Infected foci, which were stained with L. intracellularis-specific rabbit antiserum, were observed in the cell culture at 5 days post inoculation. The DNA sequence of several genes in the Japanese isolate had high similarity with those of the L. intracellularis type strain, suggesting the genetically close relationship of the two strains. This is the first report describing the cultivation and partial characterization of L. intracellularis originated in Japan.
DOI： 10.1292/jvms.68.609
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Infectivity of porcine circovirus 1 and circovirus 2 in primary porcine hepatocyte and kidney cell cultures.
Hirai T, Nunoya T, Ihara T, Saitoh T, Shibuya K, Nakamura K.
J Vet Med Sci 68 ( 2 ) 179 - 182 2006.2
Language：English Publishing type：Research paper (scientific journal)
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Hirai T., Nunoya T., Ihara T., Saitoh T., Shibuya K., Nakamura K.
Journal of Veterinary Medical Science 68 ( 2 ) 179 - 182 2006.2
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Veterinary Medical Science
Infectivity of porcine circovirus (PCV) 1 and PCV2 was examined in primary porcine hepatocyte culture by comparing that of PCV in primary kidney cell culture. The virus titer of PCV2-infected hepatocyte cultures was higher than that of the PCV1-infected hepatocyte cultures and the PCV-infected kidney cell cultures. The number of virus-positive cells was most abundant in PCV2-infected hepatocyte cultures as determined by immunohistochemistry and/or in situ hybridization. The results of our data suggest that PCV2 preferably infects cultured hepatocytes as observed in the liver of pigs with postweaning multisystemic wasting syndrome.
DOI： 10.1292/jvms.68.179
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In vitro cultivation and partial characterization of Lawsonia intracellularis from a Japanese field case of porcine proliferative enteropathy.
Koyama T, Hirai T, Nagai S.
J Vet Med Sci 68 ( 6 ) 609 - 613 2006.1
Language：English Publishing type：Research paper (scientific journal)
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Acute hepatitis in a piglet experimentally inoculated with tissue homogenates from pigs with postweaning multisystemic wasting syndrome.
Hirai T, Nunoya T, Ihara T, Kusanagi K, Kato T, Shibuya K.
J Vet Med Sci 65 ( 9 ) 1041 - 1045 2003.9
Language：English Publishing type：Research paper (scientific journal)
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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.