The effects of administration of purified erythropoietin (EPO) were investigated in four types of anemic model rats made by the injection of phenylhydrazine, iron deficiency, X-ray irradiation and partial nephrectomy. Serum EPO titers of those anemic rats were determined by radioimmunoassay. Partially nephrectomized rats showed chronically uremic anemia and their serum EPO titer remained decreased. These rats were recovered from anemia by injecting EPO. On the other hand, serum EPO titer of other types of anemic rats increased with the progress of anemia and the serum EPO titer showed reverse correlation with hemoglobin concentration. In these rats, curative effect of injections of EPO on anemia was not observed. All those results show that injection of EPO has therapeutic effect on anemia in the animals with renal failure and low serum EPO titer. However, injections of EPO did not show any effect on anemia in the animal with regular renal functions because of their own homeostatic EPO productions under anemic condition.

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Twelve cats, confirmed to be positive for group specific antigens of feline leukemia virus (FeLV) in peripheral blood lymphocytes (PBL) by an indirect immunofluorescent antibody test, were studied for interleukin 2 (IL-2) production. The production of IL-2, determined by the cell proliferation of an IL-2 dependent murine T cell line (CTLL-2), was remarkably lower in PBL from FeLV-infected cats, as compared to those from healthy controls. In particular, FeLV-infected cats with leukemia or with the thymic type of lymphosarcoma had substantially poor IL-2 production. These results suggest that the proliferative response of PBL from persistently FeLV-infected cats to Con A is reduced, associating with the lowered ability of IL-2 production at least in part.

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An infection of Contracaecum spiculigerum was seen in the proventriculus of a cormorant (Phalacrocorax carbo) kept for fishing at Leshan, Sichuan Province, People's Republic of China, in April 1985. Erosions with hemorrhages were seen in areas of the mucosa where many worms burrowed. Many nodes with worms were seen in the muscular layer and projected from the serosal surface. Most worms in the muscular layer were surrounded by cell infiltration and granulation tissue, and showed regressive changes. The tissue response was characterized by the presence of homogeneous eosinophilic substance by the degenerating worms which surrounded by the foreign-body giant cells. The 4th stage larvae of the species were thought to invade the glandular lumen and muscular layer of the proventriculus. Following development, most of the larvae may return to the lumen of the proventriculus, but some larvae may remain in the muscular layer and succumb to degeneration after maturity.

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An epizootiological survey was conducted on neonatal calf diarrhea in a beef hard for one calving season in 1981. Diarrhea occurred synchronously among calves on May 8-10, when the population density of the newborn reached a peak. The direct key factor for onset of illness was the succession of large changes in ambient temperature between daytime and nighttime. The main causative agent was diagnosed as bovine rotavirus (BRV) type 1 from the elevation of serum antibody titers, enzyme immunoassay of feces, and virus isolation. No antibody titer or no significant rise of the titer was detected against BRV type 2, BRV type 3, bovine coronavirus, or bovine viral diarrhea-mucosal disease virus. Two strains of Escherichia coli K99 (+) Ent (+) and several strains of enteroviruses were also isolated. During the incidence of diarrhea, there was a gradual decrease in atibody titer against BRV type 1 in calf serum transferred via colostrum. This titer increased over a period from July to November, when diarrhea was scarcely observed. BRV antigen was first detected in normal feces of a cow on the day of parturition, then in those of her calf on the next day, and finally in the diarrheal feces of many calves on the day of outbreak, May 10. There were cases of asymptomatic or repeated infections. Direct relationships were not always observed among symptoms, elevation of antibody titer, and excretion of viruses.

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Ultrastructural changes of the cells forming germinal centers were examined in the chick spleen after intravenous injection of sheep red blood cells. The germinal center was formed by a cluster of large lymphoid cells and a septum of flattened reticular cells. The large lymphoid cell was characterized by numerous polysomes and a large euchromatic nucleus with a prominent nucleolus. In the developing germinal center the large lymphoid cells proliferated and became smaller in size. After the peak of development of the center they were gradually atrophied and finally became degenerative to exhibit pyknotic nuclei, condensed cytoplasm, some vacuoles and many cytoplasmic processes. From the formation of the germinal center through its degeneration, the transformation of lymphoid cells into plasma cells did not occur within the center. Plasma cells were appeared in the red pulp prior to the germinal center formation, and then they proliferated to aggregate around a periarterial lymphatic sheath.

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The mouse-passive protective effect of sera from swine immunized with different fractions from inactivated broth culture of an attenuated strain of Erysipelothrix rhusiopathiae (serovar 2) was investigated. Growth-agglutinating (GA) antibody was consistently found in both of IgM and IgG fractions of the antisera against culture fractions: whole culture (WC), culture filtrate (CF), killed cells (KC) or washed killed cells (KCW). Anti-CF sera were most effective against both strains of serovar 1a and 2, whereas anti-WC or KC sera were effective only against the strain of serovar 2, and anti-KC sera were less effective. Protective activity of each serum was found in IgG fraction but not in IgM fraction. GA antibody titers of anti-CF sera lowered to levels of 1/4 to 1/16 after absorption with CF, KC or KCW. Mouse-protectivity (ED₅₀ values) of those absorbed sera was 1/1.7 or 1/4 against strain of serovar 1a or 2 (P<0.01) as compared to those of nonabsorbed antisera. Results indicated that anti-CF serum is most effective and cross-protective over the serovars and that major protective antigens of CF are derived from the bacterial cell walls.

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Clinical, hematological, and pathological studies of experimental feline panleukopenia (FPL) were carried out on 10 specific pathogen-free cats. The main clinical signs of the cats infected with FPL virus were mild diarrhea, mild transient pyrexia, depression, and anorexia. None of the cats died. In many cases, leukopenia involving neutropenia and lymphopenia were observed, though the lowest leukocyte count was approximately 6, 000/μl. Hypoplastic changes of myeloid and erythroid cells in the aspirated bone marrow, paticularly decrease of immature cells, were most common. However, recovery of the cells was very rapid. The main histopathological changes of the experimental cats were observed in lymphatic tissues. Depletion of lymphocytes and activation of the RES in the spleen and mesenteric lymph nodes, atrophy of lobules, and depletion of lymphocytes in the thymus were predominant. In addition, intranuclear inclusion bodies were found in the reticular cells of lymphatic tissue and crypt epithelial cells of the small intestine. These results indicate that the clinical, hematological, and pathological changes of experimental FPL in SPF cats are mild and that recovery from the disease is very rapid.

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A histopathological study was carried out on spontaneous subclinical lesions in 86 beagle dogs employed in toxicity studies. The lesions found in a young adult group were compared with those in an older age group. Lesions detected more frequently in the older age group included acidophilic crystalline intranuclear inclusions in the liver and kidney, cell infiltration in the submaxillary gland, a tubular fatty change and glomerular lipid deposition in the kidney, atrophy and cyst formation in the thymus, siderofibrotic nodules in the spleen, and parafollicular cell hyperplasia in the thyroid. Focal mesothelial proliferation in the epicardium of the heart, intranuclear inclusions in the epididymis, focal granulomatous inflammation in the kidney, and aberrant pancreas in the gallbladder were noted each in 1 case. Granulomas possibly caused by parasitic infection were found in 21 cases (24.4%).

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Experiments were performed to examine the effects of dextrose added to lactate Ringer solution (LR) in dogs under surgical stress conditions. The results were as follows: 1. LR with dextrose (LRD) inhibited the release of NEFA in dogs under surgical stress conditions. 2. LRD increased the content of liver glycogen of dogs under surgical stress conditions. 3. Transfusion with LRD maintained sufficient urine excretion in dogs under surgical stress conditions. From these results, it was suggestd that LRD shold be used rather than LR alone, since the addition of dextrose to LR had favorable effects on dogs under surgical stress conditions.

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Thirty-four spontaneous tumors of the central nervous system were found in 1705 male and 1705 female Fischer 344/DuCrj rats. The tumors developed in 24 (1.4%) males and 10 (0.6%) females ranging in age from 38 to 109 weeks. There were 11 astrocytomas, 5 oligodendrogliomas, 5 mixed gliomas, 5 meningiomas, 4 granular cell tumors, 2 ependymomas, one medulloblastoma, and one reticulosarcoma. The astrocytomas were divided into 4 fibrillary, 3 protoplasmic, 3 pilocytic, and one malignant types. The meningiomas were divided into 2 meningotheliomatous, 2 fibromatous, and one malignant types. One of the ependymomas originated in the tentorium cerebelli and was diagnosed as extraventricular ependymoma. Seven of 34 tumor-bearing rats revealed neurological signs and these signs were related with anatomical locations of tumors.

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The resistance of newborn mice to infection with Babesia rodhaini was studied. No parasites were detected in the neonates or fetuses of both acutely infected and chronically infected mothers. However, the neonates born of chronically infected mice and nursed by normal uninfected mothers or by chronically infected mice were significantly more resistant to the infection than those from normal uninfected mice. In experimentally infected adult mice, the activities of macrophage migration inhibitory factor (MIF) in the supernate of concomitant cultivation of spleen cells with the lysate antigen of Babesia increased up to 6 weeks after infection. The degree of peritoneal macrophage phagocytosis in infants from chronically infected mothers was significantly greater than that of normal mice. The macrophage phagocytosis of parasitized erythrocytes was enhanced remarkably when the erythrocytes were exposed to immune serum just before addition to the macrophages.

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Four strains of cytopathic agents with syncytium formation were isolated from the respiratory tract of pigs affected with respiratory diseases in Niigata and Osaka Prefectures in 1984. These viruses agglutinated with erythrocytes from mouse, hamster, rat and chicken. Multiplication of the isolated viruses in cell culture was not inhibited by IUdR. The viruses were inactivated with ether and chloroform, and were also unstable at pH 3.0. The isolated viruses passed readily through a membrane filter of 220 nm pore size, but not through one of 100 nm pore size. Coronavirus-like particles of 120-160 nm in diameter were observed by the electron microscope. In the serum neutralization test, the 4 isolated viruses were immunologically related with the 67N strain of hemagglutinating encephalomyelitis virus (HEV) and were slightly related with the No. 66 strain of bovine coronavirus (BCV). None of them were found to be immunologically correlated with the T0160 strain of transmissible gastroenteritis virus (TGEV). From these resuflts, the 4 isolated viruses were identified to be as the HEV. Conventional and colostrum-deprived piglets were inoculated with isolated HEV by the intranasal or ocular route. They showed mild coughing, sneezing with nasal discherge with some other mild clinical sign. The viruses were successfully recovered from the respiratory tract and lungs during 1 to 9 days after virus exposure. On farms N and T, the field investigations revealed that there was an increase in hemagglutination-inhibiting (HI) antibody in breeding pigs 3 to 4 months old.

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Congenital and perinatal cerebellar anomalies of 12 calves were morphologically divided into four groups. Three calves showing minor histological changes such as heterotopia of the cortex or defect of the cortical layers localized in a cerebellar gyrus were diagnosed as Akabane disease. The other two cases were characterized by bilateral partial defects of cerebellar tissue in the lateral hemispheres. The remaining three and four cases showed hypoplasia and degeneration in the cerebellum, respectively. Cerebellar hypoplasia of the former three calves was considered to be caused by BVD-MD virus infection. A pathogenesis of the cerebellar degeneration seemed diverse resulting from hypoxia during a perinatal period or increased intracranial pressure due to dysplasia of the ventricular system.

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Regional distribution and relative frequency of endocrine cells were studied in fifteen portions of the porcine gastrointestinal tract by immunohistochemical methods. Twelve kinds of immunoreactive endocrine cells were identified in this study. In the stomach, 5-HT-, somatostatin-, gastrin-, methionine-enkephalin-Arg⁶-Gly⁷-Leu⁸ (M-ENK-8)-, glucagon- and bovine pancreatic polypeptide (BPP)-immunoreactive cells were detected. The first four cell types were predominant over the other types and were more numerous in the pyloric region than in the cardiac and fundic regions. In the small intestine, 5-HT-, somatostatin-, gastrin, M-ENK-8-, motilin-, secretin-, cholecystokinin (CCK)- and gastric inhibitory polypeptide (GIP)-immunoreactive cells were widely distributed and most numerous in the duodenum, while neurotensin- and glicentin-immunoreactive cells were predominant in the ileum. Glucagon- and BPP-immunoreactive cells were rarely seen in the small intestine. In the large intestine, 5-HT-, somatostatin- and glicentin-immunoreactive cells were widely distributed and most numerous in the rectum. Motilin-, glucagon- and BPP-immunoreactive cells were rarely seen in the large intestine. It is suggested that the distribution pattern of gut endocrine cells in pigs is the most similar to that in humans among the mammalian species so far reported.

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Larvicidal activity of ivermectin against Dirofilaria immitis larvae of 30 days old was evaluated. A single oral dose of ivermectin to demonstrate complete larvicidal activity was 3μg/kg of body weight or more. Administrations of ivermectin at 0.5, 1 and 2μg/kg dose-relatedly showed incomplete antilarval activities. Administration of ivermectin at 0.5, 1 and 2μg/kg 30 days after infection caused lower levels of the sex ratios (female/male) than that of the control showing definite decrease in numbers of female worms. The average body lengths of both female and male worms recovered from dogs receiving ivermectin at 0.5, 1 and 2μg/kg, except for that of female worms at 1μg/kg, were significantly shorter than that of the worms recovered from the control dogs.

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Effects of injection of large amounts of vitamin D₃ (VD₃) on the concentrations of plasma 25-hydroxyvitamin D (25OHD), 1α, 25-dihydroxyvitamin D (1, 25 (OH)₂D), calcium (Ca) and inorganic phosphorus (Pi) in the lactating Holstein-Friesian cows were examined. The cows were divided into two groups, an untreated control group consisting of 4 cows and a treatment group (VD₃ group) consisting of 5 cows. Each cow in the VD₃ group received 10 million I.U. of VD₃ intramuscularly at 7 days after parturition. Blood and milk samples were taken from 0 to 15 days after the VD₃ injection. The plasma 25OHD concentration was significantly higher in the VD₃ group than that in the control group throughout the experimental period, whereas the plasma 1, 25 (OH)₂D concentration rose only transiently after the VD₃ injection. The plasma Ca concentration was also significantly higher in the VD₃ group than that in the control group throughout the experiment, while the plasma Pi concentration was higher in the VD₃ group only from the 3rd to 6th day of the experiment. These results suggest that the initial increase in the plasma Ca concentration may be due to the increase in the 1, 25 (OH)₂D level whereas the substained increase in the Ca concentration may be due to the increase in the plasma 25OHD concentration. Further, it seems likely that the plasma 1, 25 (OH)₂D concentration is suppressed by the increase in the plasma Ca concentration in the later stage of experiment and also by the negative feedback of plasma 1, 25 (OH)₂D concentration.

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