The normal development of Mongolian gerbil foetuses and, in particular, the timing and sequence of the appearance of ossification centres     

Yukawa M  Hayashi N  Takagi K  Mochizuki K 《Anatomia, histologia, embryologia》1999,28(5-6):319-324

To elucidate the normal development and growth of Mongolian gerbils, the timing and sequence of the appearance of ossification centres within foetuses were investigated. Average foetus body weight and tail length on the 15th day of pregnancy were found to be 0.042 g and 6.2 mm, respectively. For the 25th day of pregnancy, these measurements were 2.601 g and 29.4 mm, respectively. The body weight and tail length of foetuses increased significantly from the 20th day of pregnancy. Also, the first ossification centre of Mongolian gerbil foetuses appeared in the clavicle at the 17th day of pregnancy. The order in which ossification centres appeared in Mongolian gerbils resembles the pattern for rats and mice, except in some areas of the skull. Except for the clavicle, in which ossification centres appeared rather early, most ossification centres appeared in the last quarter of pregnancy. These results suggest that Mongolian gerbil foetal development is near completion by the last gestational stage. Also, ossification centres appear sooner in the skull and nasal bones than in other rodents.  相似文献   

Spontaneous pinealoma in a male Crj:CD (SD) IGS rat     

Furukawa S  Kobayashi K  Usuda K  Tamura T  Miyamoto Y  Hayashi K  Ikeyama S  Goryo M  Okada K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(1):41-44

A pinealoma (benign) was found in a 61-week-old male Crj:CD (SD) IGS rat. The neoplasm was located between the cerebral hemispheres and the cerebellum. Histologically, the tumor cells consisted of two cell types: large, pale-staining cells and small dark-staining cells. A fibrovascular stroma divided the tumor cells into incomplete lobules or nest structures. Relatively numerous mitoses were noted in the tumor cells. Ultrastructurally, the tumor cells contained dense-cored vesicles, approximately 120 nm in diameter.  相似文献   

Outbreak of canine parvovirus infection and its elimination in a closed beagle dog colony     

T Hirasawa  S Iwaki  K Watanabe  K Mikazuki  S Makino  Y Hayashi 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1987,34(8):598-606

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Disposition of sulfonamides in food-producing animals: pharmacokinetics of sulfamerazine in ewe lambs     

M Hayashi  D W Bourne  R F Bevill  G D Koritz 《American journal of veterinary research》1979,40(11):1578-1582

Date from plasma and urine samples from four ewe lambs were analyzed after administration of sulfamerazine as single IV and oral doses. A two-compartment pharmacokinetic model was developed to describe the disposition of sulfamerazine. The drug was eliminated, primarily by renal excretion of (i) unchanged sulfamerazine and metabolism to an acetyl metabolite, (ii) polar conjugates, and (iii) a third metabolite. The biological half-life of the drug was 6.6 hours. The average value of the absorption rate constant was 0.433 hour-1 (half-life 1.60 hours). Sulfarmerazine was relatively completely absorbed (approx 81% of dose) after oral administration in solution.  相似文献   

Nephroblastoma with liver and lung metastases in an adult dog     

H Nakayama  T Hayashi  R Takahashi  K Fujiwara 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1984,46(6):897-900

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Geographical variation of skull morphology and its functional significances in the red-cheeked squirrel     

Endo H  Kimura J  Oshida T  Stafford BJ  Rerkamnuaychoke W  Nishida T  Sasaki M  Hayashida A  Hayashi Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(11):1179-1183

Skulls of the red-cheeked squirrel (Dremomys rufigenis) from various geographical locations: Malaysia (peninsular area), Vietnam (south district)-Laos, and Thailand (north district) were osteometrically examined. The skull size of the squirrels in the southern (Malaysia) population was fundamentally larger than that in the northern (Vietnam, Laos and Thailand) populations. The proportion indices indicated that the splanchnocranium was relatively longer in the Malaysia population, and that the interorbital space was narrower in Vietnam-Laos, and Thailand populations. We suggest that the long nose and laterally-oriented orbits in the skull may be better adapted for terrestrial-insectivorous life in the Malaysia population and the binocular sense facilitated by rostrally-oriented eyes contributes to the arboreal-fruit eating behavior in the two northern populations. The Malaysia population was clearly distinguished from the other populations by the principal component analysis. We suggest that the geographical barrier of the Isthmus of Kra influences the morphological variation of the skull among the squirrel populations.  相似文献   

Cerebellar ataxia due to Toxocara infection in Mongolian gerbils,Meriones unguiculatus   总被引：3，自引：0，他引：3  

Akao N  Tomoda M  Hayashi E  Suzuki R  Shimizu-Suganuma M  Shichinohe K  Fujita K 《Veterinary parasitology》2003,113(3-4):229-237

We assessed the usefulness of gerbils as an experimental model for neurologic toxocarosis. Mongolian gerbils, Meriones unguiculatus, infected with Toxocara canis or Toxocara cati (1000 eggs/gerbil) showed progressive neurologic disorders from 50 days after infection in T. canis-infected gerbils or from 120 days after infection in T. cati-infected gerbils. The incidence of the onset was 6 of the 13 gerbils (49%) in the T. canis-gerbils and 5 of the 7 gerbils (71%) in the T. cati-gerbils. Histopathologically, the cerebellum was the most affected in both groups. We observed loss of Purkinje cells, glial nerve fibers, and nerve sheaths. We also found foci consisting of aggregated macrophages scattered in the white matter of the cerebellum. The affected gerbils showed ataxia and ultimately died of cachexia. Our findings suggest that irreversible neurologic toxocarosis in gerbils can be induced by infection with either T. canis or T. cati.  相似文献   

Evaluation of cytokine messenger RNA expression in peripheral blood mononuclear cells from dogs with canine demodicosis     

Tani K  Morimoto M  Hayashi T  Inokuma H  Ohnishi T  Hayashiya S  Nomura T  Une S  Nakaichi M  Taura Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(6):513-518

Using RT-PCR and semi-quantitative PCR, mRNA expression for canine interferon (IFN)-gamma, interleukin (IL)-2, IL-4, IL-5, IL-10, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta in peripheral blood mononuclear cells (PBMCs) was examined in dogs with or without demodicosis. mRNA expression for IFN-gamma as well as TNF-alpha in dogs with demodicosis (localized (LD) and generalized (GD)) was slightly lower than those in dogs without demodicosis (healthy controls). Expression of IL-5 mRNA in dogs with demodicosis was higher than that in control dogs, but there were no significant differences in IL-4 and IL-10 mRNA expression levels among the three groups. On the other hand, expression levels of TGF-beta mRNA in dogs with GD were higher than those in control dogs and dogs with LD. The expression levels of IL-5 and TGF-beta mRNA decreased in all three dogs with GD which showed resolution of the clinical signs. Taken together, these results suggest that the Th2-like response in PBMCs from dogs with demodicosis is up-regulated, and that subsequent increased expression of IL-5 and TGF-beta mRNA in dogs with GD is reversible after treatment. Therefore, these cytokines, particularly IL-5, might be a useful clinical index of the clinical course in demodicosis. Also, increased TGF-beta mRNA expression might be a key factor for revealing the difference in the mechanism of onset between LD and GD.  相似文献   

Expression of T helper 1 and T helper 2 cytokine mRNAs in freshly isolated peripheral blood mononuclear cells from dogs with atopic dermatitis     

Hayashiya S  Tani K  Morimoto M  Hayashi T  Hayasaki M  Nomura T  Une S  Nakaichi M  Taura Y 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2002,49(1):27-31

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Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles     

Endo H  Aoki R  Taru H  Kimura J  Sasaki M  Yamamoto M  Arishima K  Hayashi Y 《Anatomia, histologia, embryologia》2002,31(4):206-213

The masticatory muscles and their related structures of the skull were observed in the Indian gavial (Gavialis gangeticus), the false gavial (Tomistoma schlegelii), and the African slender-snouted crocodile (Mecistops cataphractus) to detail some morphological differences in comparison with the other crocodile species, and to compare and elucidate the functional strategy of themasticatory apparatus in these long-snouted species. The Musculus pterygoideus posterior was relatively smaller in the three species compared with many short-snouted crocodiles. It suggests that the masticatory power in fish-eating long-snouted species is not so high as in the short-snouted crocodiles, while the masticatory muscles were morphologically different among the three long-snouted species as follows. The M. pterygoideus posterior of the false gavial was extended in the lateral side of the lower jaw unlike the Indian gavial. The M. pseudotemporalis and the Fenestra supratemporalis were largely developed in the Indian gavial, however we suggest that the other two species possess the weak bundles in this muscle. The false gavial and the African slender-snouted crocodile have the pterygoid bone well-developed extending dorso-ventrally and it is suggested that the M. adductor mandibulae posterior attached to the pterygoid bone may be much larger than the Indian gavial. These data morphologically clarify the masticatory mechanism in the long-snouted crocodiles different from the short-snouted species, and demonstrate that the evolutional strategy to share the functional role in the masticatory muscles have been differently established between the Indian gavial and the other two species. We also obtained the morphological data in the fossil skull of the Machikane crocodile (Toyotamaphymeia machikanense) and concluded from the fossil characters that the considerable developments of the M.pterygoideus posterior and the M.pseudotemporalis in this species had not morphologically been consistent with both the Indian and false gavials.  相似文献