Granulosa-cell tumors of 4 cases and theca-cell tumor of one case were pathologically investigated. Two cases of granulosa-cell tumor represented folliculoid type, forming folliculoids resembled to follicles of an ovary. On the other hand, parenchymatous type of two cases was composed of the cells with atypical characters, and revealed no obvious folliculoid structures. One case of them represented metastatic lesions in many organs. Theca-cell tumor was composed of atypical cells showing various cellular arrangements. Metastaic lesions were also noted. Ultrastructurally, granulosa-cell-tumor cells of folliculoid type contained well-developed rough-surfaced endoplasmic reticulums and Golgi-complex remarkably. Concentric lamellar bodies, fat droplets and fine filaments were also noticeable.

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Histopathololgical observations were performed on the heart and cardiac nervous system of 5 horses affected with wandering pacemaker. The histopathological lesions common to all the animals were as follows: (1) Focal fibrosis in the atrial myocardium just beneath the subendocardium and/or in the endo- and subendocardium, and existence of atrial Purkinje-like fibers within the fibrotic lesions, (2) Microvascular altetation, characterized by edematous-loosening and/or fibrous swelling of the walls of the small and minute arteries, in both the atria, (3) Edema in the intracadiac nerves of both the atria, (4) Multifocal loss of nerve fibers in the extracardiac nerves of both the sympathetic and vagal systems, and (5) Medial degeneration in the pulmonary artery and aorta. The atrial focal lesions of myocardial and endo- and subendocardial fibrosis should be regarded as a result of local circulatory insufficiency (ischemia) due to the microvascular alteration. The Purkinje-like fibers witihin the atrial fibrotic lesions might have been given temporary automaticity and, at the same time, might have been under a condition of cardiac nervous fluctuation due to the organic disturbances in both the sympathetic and vagal systems.

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The role of the spleen in feline haemobartonellosis was studied experimentally in 19 cats. The relationship between parasitemia and hematocrit (Ht) value, and the site of sequcstration in ⁵¹Cr-labeled parasitized erythrocytes were mainly examined in both splenectomized and non-splenectomized cats. In splenectomized cats the Ht value showed no significant changes in the early stage of infection in spite of the appearance of Haemobartonella felis on erythrocytes. In cats with the spleen intact it showed remarkable changes corresponding to the appearance and disappearance of the organism on erythrocytes during the experimental period. The splenic radioactivity of infected cats was six times as high as that of normal cats even in the early stage of infection. It increased markedly according to an increase in number of organisms appearing on erythrocytes. The hepatic and pulmonary radioactivity of infected cats showed only a slight or moderate increase in the severe stage of infection. On the contrary, the radioactivity of the organs examined in splenectomized cats did not increase significantly in the early stage of infection, although the radioactivity of liver, lung and bone marrow in these cats was two to three times as high as that in control animals in the severe stage of infection. In addition, parasitemia persisted apparently for a longer time in splenectomized cats than in cats with the spleen intact. From these results it is assumed that parasitized eryrthrocytes in cats infected with H. felis may be sequestrated mainly by the spleen and that the organism may be removed from host cells, without destroying the same cells in the spleen.

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Tracheal ring sections were obtained from 19- to 20-day-old chicken embryos of the specific pathogen-free layer type. They were cultured in roller tubes containing Eagle's basal medium with addition of 200 U/ml of penicillin G, 0.05 M N-2-hydroxyethyl-piperazin-N'-2-ethanesulfonic acid, and 1% porcine serum. The motility of cilia was preserved in the best conditions for 7 to 11 days in the medium, and for a few days or less in the serum-depleted medium. Mycoplasma synoviae strains F2-C AS and WVU 1853 and M. gallisepticum strain S6 were hardly or not grown in the medium without tracheal organs. In the tracheal organ culture, however, growth of microorganisms took place independent of the presence of porcine serum. The cilia-stopping effect of the M. synoviae strains in the cultured tracheal tissue was milder than that of the M. gallisepticum strain tested. Mycoplasmas were found to have been grown and attached to cilia and epithelial cells when examined in electron micrographs and fluorescent antibody micrographs. Relationship between the virulence and cilia-stopping effect and the cytopathogenicity of the mycoplasmas are discussed.

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Clinical, pathological and virological examinations were carried out on naturally occurring cases of canine herpesvirus (CHV) infection. The first clinical sign observed was diarrhea, followed by anorexia, vomiting, serous nasal discharge and dyspnea. Some puppies had continual crying, abdominal pain and incoordination. The charactetistit lesions of CHV infection consisted of disseminated focal necrosis, hemorrhages and the appearance of intranuclear and cytoplasmic inclusion bodies in many organs and tissues. Furthermore, characteristic herpesvirus particles were detected by electron microscopy in the typical intranuclear and cytoplasmic inclusions found in occasional hepatic cells. Herpesvirus was isolated from the various organs of eight affected puppies. The isolate (GCH-1), which was propagated in DK cells, was similar to other herpesviruses in physicochemical and morphological characteristics, and was immunologically related to the known CHV strains. The GCH-1 strain, following inoculation into susceptible puppies, produced the typical clinical signs and lesions that were found in the natural case. In a serological survey, neutralizing antibodies against the virus were not found in 130 sera obtained from local mongrel dogs in the Aichi and Gifu prefectures. This paper reports the first naturally-occurring outbreak of CHV infection of neonatal puppies in Japan.

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The values of each cholesterol fraction and lecithin cholesterol acyltransferase activity in serum were calculated simultaneously in canine dirofilariasis of various severity. In the mild dirofilariasis, the serum free cholesterol value increased (p<0.01) and both cholesterol ester ratio and lecithin cholesterol acyltransferase activity decreased (p<0.01), as compared with those in the normal healthy case. In the severe case which presented most serious clinical signs and liver dysfunction, the serum free cholesterol concentration approximately doubled (p<0.005) that of controls, the ester ratio was about 30 percent lower (p<0.005) than the normal, and lecithin cholesterol acyltransferase activity decreased to approximately 40 percent of the normal (p<0.005). Moreover, the serum free cholesterol value was about 20 percent larger (p<0.05), and the ester ratio about 10 percent smaller (p<0.05) than that of the mild case. Lecithin cholesterol acyltransferase activity tended to be lower than that in the mild case, though with no significant difference. There was no significant difference either in serum total cholesterol between any case of severity and the control. In all the cases, from the control to the severe one, a relatively high correlation was shown between serum free cholesterol value and lecithin cholesterol acyltransferase activity (γ=-0.75). A relatively low correlation, however, was noticed between lecithin cholesterol acyltransferase activity and ester ratio (γ=0.48). It was concluded that, in canine dirofilariasis, the scrum free cholesterol value increased with the advance in severity of the disease, and that there was a correlation between A/G ratio determined by the liver function test and the serum free cholesterol value in individual cases.

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The nephrort and ureteral system in the fowl were investigated by the anatomical and histological observation. The nephron was classified into Nephronum corticale and medullare according to their location in the lobule. The collecting duct system carrying urine from nephron to ureter was also divided into the cortical and medullary parts, i.e., Ductulus colligens perilobularis and Ductulus colligens medullaris. Ductulus colligens perilobularis was classified in five types according to the branching modes of the Tubulus colligens. The Ductulus colligens medullaris gathering many Ductulus colligens perilobularis becames the ureteral branch and drains into the ureter. In the cross section of the Lobulus medullaris, the histological feature of the Ductulus colligens medullaris was rosette or clump in outline. These features are shown in Table 3. The ureteral branches ramifying from the proximity of the ureter to the terminal were named the Rami ureterici primarii, secundarii, and tertiarii, in regular order. The average numbers of the Rami ureterici primarii in the Divisio renalis cranialis, media and caudalis were 9.93, 5.14 and 1.43, respectively, and total average number was 16.50. The branching interval of the Rami ureterici primarii in the Divisio renalis media was wider than that in the Divisio renalis cranialis, and in the Divisio renalis caudalis it was variable.

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