A total of 54 strains of Mycoplasma hyopneumoniae isolated from porcine pneumonic lungs in Japan during 1970 to 1981 and neotype strain J were investigated for their in vitro susceptibility to 13 antibiotics. Of the drugs tested tiamulin showed the highest activity with minimal inhibitory concentration (MIC) of 0.02 or 0.04 μg/ml. Lincomycin and most of the macrolides and tetracyclines also showed low MIC values. The exceptional macrolide was erythromycin to which all the strains tested did not show significant susceptibility. Among tetracyclines, chlortetracycline (CTC) showed the lowest activity with MIC range from 2.5 to 40 μg/ml. Other tetracyclines, including tetracycline, oxytetracycline and doxycycline showed relatively broad MIC range from 0.04 to 2.5 μg/ml. Most of the strains isolated in 1970 were susceptible at the concentration of 5 μg/ml or lower to CTC and 0.16 μg/ml or lower to other tetracyclines, while only less than half of the strains isolated during 1979 to 1981 were susceptible at these concentrations. Aminoglycosides (neomycin and kanamycin) showed relatively high MICs for all the strains except for a few strains.

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Athymic nude mice with background of BALB/c, C3H/He, DDD or ICR were examined for production of ascites after infection with a low-virulence mouse hepatitis virus, MHV-NuU. Ascites was prduced only in some ICR-nude mice, showing higher virus titers in the omentum than in those with other backgrounds. The incidence was age-dependent, being the highest in 8- to 13-week-old mice. In ICR-nude mice, IgG and IgM antibody titers were higher than those of BALB/c- and DDD-nude mice. Two weeks after inoculation the ICR-nude cases with ascites showed severe peritonitis forming giant cells and they had less severe lesions in the liver parenchyma. On the contrary, infected BALB/c- and DDD-nude mice had severe necrosis or fibrosis in the liver and mild lesions in the peritoneum.

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Microscopic lesions and deposition of IgG and C3 were examined by light and fluorescent microscopy in the kidneys from 100 slaughtered pigs of about six month-old. Ninety-six pigs had diffuse or focal glomerulopathy. The most common lesions were global or segmental mesangial enlargement due to hypercellularity, increased mesangial matrix and deposits of hyaline materials. In 26 out of 100 pigs, cells containing hyaline globules were present in the mesangium. In a few pigs, these cells accumulated in segments of glomerular tufts, showing mesangiolysis. Ninety-seven pigs had massive and/or granular deposits of IgG predominantly in mesangial areas; one of these pigs had heavy deposits along the glomerular capillary walls. The distribution of specific fluorescence for IgG was diffuse global, diffuse segmental or focal segmental. The kidneys of 98 pigs stained positively for C3 deposit. The location and distribution of C3 were identical to those of IgG. These findings indicate a high incidence of glomerulopathy in swine.

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A fluorometric DNA synthesis assay was developed for the determination of bovine lymphocyte blastogenic response. This method relies upon measuring the DNA contents of lymphocytes using ethidium bromide instead of measuring radioisotope [³H]-thymidine uptake. Fluorescence intensity of cultured lymphocytes was highly correlated with [³H]-thymidine incorporation (r=0.967, P<0.01, n=50). The mean coefficient of variation of this method was 3.4% which is one-third of that of the [³H]-thymidine uptake assay (10.3%). Optimal cultural conditions were as follows; Concentrations of concanavalin A (Con A), phytohaemaggulutinin-P (PHA), and pokeweed mitogen (PWM) were at 5 μg/ml, 1μl/ml, and 10μg/ml, respectively, when 5×10⁵ lymphocytes were incubated for 72 hours. Mitogenic responses of post partum cows [within 1.6 weeks (mean) after parturition] were depressed significantly when compared with those of lactating cows. The main advantages of the fluorometric DNA synthesis assay are safety, simplicity and reliability. The method is widely applicable for evaluating lymphocyte blastogenic responses.

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The influence of food restriction on the prolactin surges and circadian adrenocortical rhythms was investigated in pseudopregnant rats. Two groups (G-1 and G-2) of rats were maintained under 14L:10D (G-1: lights on 0500-1900 h, G-2: lights on 1700-0700 h), and allowed to feed ad libitum or to feed restrictedly only between 0900 and 1100 h every day for 4 weeks. Pseudopregnancy was induced 23 days after the initiation of the food restriction by uterine cervical stimulation performed on the proestrous day. Under ad libitum feeding, nocturnal and diurnal surges occurred at 0300 and 1800 h (G-1), and at 1500 h and 0600 h (G-2) respectively, suggesting that these prolactin surges are adjusted to lighting conditions. Restriction of food availability to 2 hr did not affect the nocturnal surge (G-1, 2). In contrast, the diurnal surge in individual rats occurred either irregularly or disapperared, and no significant diurnal surge was detected from the pooled data. The circadian adrenocortical rhythm adjusted to altered feeding time progressively, with the peak level immediately before the feeding time. These results are discussed in relation to the hypothesis that multiple neural oscillators may control the bimodal prolactin surges in pseudopregnant rats.

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An outbreak of fowl cholera occurred in a wild duck (Rosyibilled pochard) flock at a zoological garden in Gunma prefecture of Japan in March and May of 1983. Twenty-eight (68%) of 41 birds in the flock died of an acute disease. Pasteurella multocida was isolated in pure culture from heart, lung, liver, kidney and spleen of a representative bird. Serovars of the isolate were identified as Carter's capsular type A, Heddleston's type 3, and Namioka's type 8:A. Multiple petechiae were macroscopically observed in the heart, lung, liver, spleen, subcutaneous fatty tissues, and nervus vagus of ischium and neck of the bird. Microscopically, multiple areas of necrosis and bacterial aggregates were apparent in the liver and spleen, and thrombi and bacteria were apparent in the heart, lung and some nervous tissues. These etiological and pathological findings indicated that the infection was typical fowl cholera. This is the first report on the occurrence of fowl cholera in wild waterfowl in Japan.

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Fifty-six parathyroid glands from 41 horses were examined with hematoxylin-eosin staining and immunoperoxidase method using rabbit anti-human calcitonin antiserum and an electron microscope. C cells filled with immunoreactive secretory granules and distinguished from nonreactive parathyroid cells were found in 42 cases of the equine parathyroid glands. The morphological characteristics and the sensitivity to the anti-calcitonin antiserum of C cells in the equine parathyroid glands were almost identical with those of C cells in the equine thyroid glands. The parathyroid C cells were much more eosinophilic than the chief cells and the water clear cells in hematoxylin-eosin staining. The ultrastructural features of C cells were apparently different from those of the so-called oxyphil cells. They possessed abundant secretory granules of various sizes and were separated from the stroma by a basement membrane together with other parathyroid cells. Desmosomes were found at sites attached to neighboring cells, and half-desmosomes at sites attached to a basement membrane. No transitional cells between the oxyphil cells and the C cells were observed. This study showed that the immunoreactive C cells in the equine parathyroid glands appeared more frequently in parathyroids fused with thyroids than in ones freed from thyroids. No apparent differences could be observed in the frequency of occurrence of C cells owing to breed, age, and sex of the horses.

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Blastogenesis of canine peripheral blood lymphocytes (PBL) against phytohemagglutinin (PHA) was measured by the glucose consumption test (GCT). Two hundred thousand lymphocytes isolated from a dog were placed in a flat-bottomed microplate in DM-160 medium supplemented with 15% normal canine serum (incubated at 56°C for 30 minutes) and 20μg/ml PHA-P (final concentration). The plate was sealed tightly and incubated for 96 hr at 38°C. The mean of SR value on 34 clinically healthy dogs was 73.8±20.0% under those culture conditions and there was a high correlation (r=0.79, P<0.01) of results obtained between this test and the fluorometric microassay of DNA in mononuclear cell using ethidium bromide. The blastogenesis of PBL was inhibited significantly (P<0.05) by the treatment with mitomycin C. The SR value of lymphocytes of which isolated from six dogs with experimental lobectomy was decreased from 49.7±22.9% to 16.3±15.0% after operation. GCT was able to reveal a statistical depression (P<0.05) of lymphocyte blastogenesis after operation. In brief, this test could detect efficiently a depression of lymphocyte blastogenesis in vitro and in vivo. In conclusion, this GCT was regarded as a new effective method for measurement of blastogenesis of canine PBL.

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Thirty-three nulliparous female rats (Wistar-Imamichi) were mated and the changes in fetal and maternal body weight, placental weight, maternal heart rate (MHR), maternal blood pressure (MBP) and fetal heart rate (FHR) were determined throughout the gestational period. Using twenty-two out of the same rats, autonomic drugs (norepinephrine: NE, isoproterenol: Isp, acetylcoline: ACh) were administered i.v. to pregnant rats or i.p. to fetus and the changes in MHR, MBP and FHR were examined. Through the gestational period, maternal and fetal body weight increased exponentially. MHR and FHR gradually increased, while MBP decreased at the end of gestational period. After the administration of autonomic drugs to dams, the responses of maternal parameters were the same as those in the non-pregnant rats. But MBP following NE and MHR following Isp administration to pregnant rats showed a larger increase than those to non-pregnant rats. The administration of autonomic drugs to mother rats caused a transient decrease in FHR, which was the largest when Isp was administered, and it became larger as the term approached. Direct administration of Isp to fetus caused an increase in FHR, while ACh caused a decrease. The magnitude of these responses grew larger as the term approached.

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A strain of Eimeria necatrix isolated in Miyazaki Prefecture, Japan, was examined for its sensitivity to 13 anticoccidials. Nine out of the 13 drugs were not efficacious, but three quinolone derivatives and robenidine were efficacious at their recommended dose-levels. Minimal effective concentration levels of decoquinate (one of the quinolone derivatives) and robenidine were approximately one-tenth of the recommended dose levels of munufacturers: 4 ppm for decoquinate and 4.125ppm for robenidine. Therefore, we examined the reduction in sensitivity of this strain to these drugs by serially passaging in chickens fed the ration containing suboptimal dose-levels of these anticoccidials. The strain deteriorated the sensitivity to minimal effective concentration levels of decoquinate and robenidine after 50 and 10 passages, respectively. However, the strain was still highly sensitive to recommended-dose levels of decoquinate and robenidine after 50 and 40 passages, respectively.

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A minute extravasated blood spot appeared in a space between the base of chorionic stem villi and caruncular septa as early as the 76th day of gestation, increased in number and size with the progress of gestation, and developed to the hematoma after 150 days of gestation. Epithelial layer of the caruncular septal tissue facing the arcade zone contained a large quantity of lipid droplets and showed signs of degeneration. Degenerative products are assumed to be absorbed by the trophoblast as a histotrophe. In addition, the trophoblast layer of the chorion facing the hematoma showed a distinct erythrophagocytosis of extravasated blood cells with the progress of gestation. Trophoblast cells lining an arcade zone were high columnar and showed well developed organelles suitable for strong phagocytosis. The activity of acid phosphatase was detected only in the trophoblast of the arcade zone. Processes of the ingestion and digestion of erythrocytes were almost similar to those described by earlier authors in other types of placentae. Intercellular space being developed particularly in a basal zone of the trophoblast seemed to be the important channel to transport the digested material. Erythrophagocytizing trophoblast layers often invaginated into the mesenchyme. Trophoblast cells of these invaginated layers usually contained abundant hematogenous pigment in a basal zone. These facts suggest that the intracellular digestion of erythrocytes requires a long time.

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Using immunoperoxidase method the production of liver lesions and propagation of organisms were observed in mice intravenously inoculated with MSK strain of Tyzzer's organisms and treated with cortisone. Microbial antigen was first detected on Day 2 postinoculation (p.i.) within very small necrotized foci. On Day 3 p.i. or later when necrotic foci with neutrophil infiltration increased in size and number, many immunoperoxidase-positive bacteria were present within seemingly living hepatocytes at the periphery of lesions but not within the necrotized foci. Apart from large-sized necrotized foci some hepatocytes carrying abundant bacterial antigen were singly present without inducing any mesenchymal response. At the moribund stage, neutrophils as well as Kupffer cells were found to carry bacterial antigen in the sinusoidal spaces without showing morphologic evidence of bacterial growth. Electron microscopy revealed that antibody specifically combined with the flagella and bacterial surface.

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A heartworm mass was confirmed by echocardiography at the tricuspid valve orifice of dogs with dirofilarial hemoglobinuria (caval syndrome). It disappeared by surgical heartworm removal, and the symptoms of "caval syndrome" also improved. The plasma hemoglobin concentration, which was very high before heartworm removal, decreased 30 min after heartworm removal. It fell progressively to almost the normal level 20 hr after heartworm removal. In 5 dogs developing the caval syndrome after milbemycin D administration, the presence of heartworms at the tricuspid valve orifice and the increase of plasma hemoglobin concentration were observed to occur simultaneously. These findings suggest that the heartworm mass at the tricuspid valve orifice may be a direct cause of the onset of this disease, and these heartworms may trigger the increased intravascular hemolysis.

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Pharmacokinetics of sulfadimethoxine (SDM) after 3 intravenous doses (10, 30 and 90mg/kg) was studied in 5 cocks (8 months old). The plasma concentration curves after 30 and 90mg/kg doses showed a nonlinear pharmacokinetics, in which the initial elimination curves were declined slower with increasing doses. The corrected values of the area under the plasma concentration versus time curves (AUC) which were obtained by divided AUC of SDM by the ratio of 30 and 90mg/kg doses to 10mg/kg dose, increased dose-dependently. SDM, N⁴-acetyl of SDM (Ac-SDM) and an unknown metabolite of SDM (UK-metabolite) were found in the excreta. The excretion of SDM and Ac-SDM was decreased with time, but the excretion of UK-metabolite was apparently nonlinear excretory kinetics after 30 and 90mg/kg doses. These results may suggest that the saturation of elimination of UK-metabolite is a possible causative prosses of the nonlinear pharmacokinetics of SDM in cocks. The UK-metabolite was suggested to be a new metabolite because of resistance to hydrolysis by β-glucuronidase or 2N HCL.

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The transformation of mitogen stimulated bovine lymphocytes was studied using the glucose consumption test. After four days of incubation of lymphocytes, the glucose concentration in the culture medium was determined. The differences of glucose concentration between control and mitogen stimulated cultures indicated the blastogenetic activity of the lymphocytes. Of four mitogens used, phytohaemagglutinin and concanavalin A responded well whereas responces with lipopolysaccharide and pokeweed mitogen were weak. This simple method was useful in evaluating the blastogenesis of bovine lymphocytes for routine use.

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The protective effect of active and passive immunization against bovine leukemia virus (BLV) infection was tested in sheep. Eight sheep were immunized 3 times at 2-week intervals with concentrated BLV antigen treated with Triton X-100. Two weeks after the last immunization, when antibody titers to glycoprotein (gp) (gp antibody) were 32 to 256, 4 of the 8 immunized sheep were challenged with infected sheep blood and remained uninfected. These 8 sheep were challenged or rechallenged when their gp antibody titers fell to 1 to 8, and all animals were infected. Of 10 sheep immunized passively with various doses of immunoglobulin obtained from infected sheep serum, animals that had gp antibody titers of 64 showed protection against challenge inoculation. To sum up the relationship between serum antibody titers and protective effect, all sheep that had gp antibody titers of 64 or more and half the sheep that had titers of 32 showed resistance to infection. Resistance was observed in only one of the 13 sheep that had titers of 16 or less.

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Further carcinogenicity study on methylmercury chloride (MMC) was conducted in ICR mice (60/sex/group) to confirm our earlier finding that MMC was a renal carcinogen in male ICR mice. MMC was fed to mice at dietary levels of 0, 0.4, 2, or 10ppm for 104 weeks. Renal tumors, mostly adenocarcinomas, were induced only in male mice of the 10ppm group. The first case with a renal tumor was observed at 58 weeks of the study. The tumor incidence was 50% (13/26) in the 10ppm group. Average intake of MMC in this group was 0.906mg/kg/day. No renal tumors were induced in other groups including females.

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When the body temperature of a male rat was lowered under anesthesia, it was recognized that the electrocardiographic T wave was consistently altered to a characteristic bifid T feature at rectal temperatures roughly between 30°and 20°C. The prolongation of QT interval was marked with the decrease of rectal temperature. This bifid T wave was restored to its original monofid one by artificially raising the rectal temperature above 30°C or further lowering below 20°C. The bifid T wave returned to normal by propranolol (4mg/kg, i.p. or i.v.), or by the infusion of procaine solution (2%, 0.2ml) into spinal subarachnoid space at the level of cervical region (C1-C2). On the other hand, from the rat pretreated with reserpine (5mg/kg, i.p.), no bifid T wave was observed even under hypothermia. The prolongation of QT interval in relation to the body temperature in the reserpine-pretreated rat was less marked than that in the nonpretreated rat. The normal T waves in the normothermic rat as well as in the reserpine-treated normothermic and hypothermic rats were transiently altered to bifid ones by the intravenous administration of isoproterenol (3μg/kg). These results led the authors to conclude that the hypothermia causes an increase in sympathetic nervous activity in rats and that the bifid T wave is mainly due to the augmented activation of cardiac adrenergic β receptor.

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Lactate dehydrogenase isoenzyme anomaly was detected in a 5-year-old male mongrel cat with liver disease. The serum LDH zymogram in this case revealed a high percentage of LDH₂ and two extra bands close to the anodic and cathodic sides of a missing band of LDH₄. These extra bands with abnormal electrophoretic mobility were confirmed by enzyme-immunoelectrophoresis to be originated from a linkage of LDH isoenzyme to IgG.

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Ten dogs with hyperglycemia and/or glucosuria were examined for pancreatic and renal changes. Microaneurysm, nodular or diffuse sclerosis, obliteration or exudative lesion in the renal glomeruli were seen in association with islet atrophy and vacuolation of islet cells, necrosis and chronic inflammation in the pancreas.

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Coccidioidomycosis was diagnosed in a 9-year-old Holstein-Friesian cow slaughtered at an abattoir in the Awaji-shima of Hyogo Prefecture. The subject had a large abscess in one of the mediastinal lymph nodes. The abscess was surrounded by a thick pyogenic membrane with granulation tissue and contained young to mature spherules with endospores of Coccidioides immitis.

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Five cases of young ferrets infected with Aeromonas species were observed pathologically. Macroscopic observations revealed irregular-shaped white hepatic foci, and hemorrhage and ulceration in the stomach in almost all cases. Microscopically focal necroses were detected in such organs as the liver, spleen, lung, heart, lymph node and adrenal gland. Particularly conspicuous were the hepatic lesions showing necrobiosis and coagulation necrosis of liver cells and the presence of numerous organisms in the sinusoids. Although the activation of Kupffer cells was remarkable, other inflammatory cells such as leucocytes and mononuclear cells were hardly seen. From these findings, it was suggested that focal hepatic necrosis was characteristic of Aeromonas infection in the ferret.

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A case of swine hyostrongylosis was parasitologically and pathologically studied. The fundic region of the stomach harboring Hyostrongylus rubidus included the following changes; hyperemia, cell infiltration and granuloma formation in the lamina propria as well as hyperplasia of lining epithelium on the surface of the mucosa. Proliferation of the epithelial lining of the mucous layer was also observed in the pyloric region of the stomach infected with H. rubidus. The present case may be regarded as a mild infection, since neither ulceration nor hemorrhage was noted in the gastric mucosa of the fundic region.

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Cerebrospinal lesions of chicks experimentally infected with avian encephalomyelitis (AE) virus were investigated morphologically. Central chromatolysis in motor neurons was mostly reversible, while affected Purkinje's cells revealed necrosis with glial reaction. Direct fluorescent antibody technique revealed various amounts of granular antigen in Purkinje's cells of all chicks showing marked leg paralysis. AE virus particles, 25nm in diameter, were found in crystalline arays in the cytoplasm of the same cells.

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Chondrifying fibrosarcoma was found in the abdominal cavity of a bovine female fetus (Holstein-Fresian breed) aborted at the 8th month of gestation. Autopsy revealed several huge to small neoplasms in the abdominal cavity. Microscopically, marked proliferation of immature fibroblastic cells were noted with moderate numbers of collagenous fibers. Chondrifying foci of variable sizes and of various stages of maturation were scattered in the tumor.

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Astrocytoma occurring in the thoracic spinal cord was found in a male 74-week-old Sprague-Dawley rat. Histologically, the densely proliferating neoplastic cells were polyhedral in shape and had hyperchromatic oval nuclei and relatively scanty cytoplasm with apparent glial fibers. Some of the cells were positive in the immunohistochemical method to glial fibrillary acidic protein (GFAP). Ultrastructurally, the tumor cells were characterized by various vesicles and scanty microfilaments in their cytoplasm.

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The failure of Yersinia enterocolitica, serotype 03, to grow in naturally infected raw pork was observed at both a refrigeration temperature of 6°C and a room temperature of 25°C. The rapid growth of environmental Yersinia organisms and aerobic microbial flora was observed in the raw pork at both the refrigeration and room temperatures. It appears that the growth of Y. enterocolitica serotype 03 may be suppressed by environmental Yersinia organisms and aerobic microbial flora normally present in raw pork.

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In the liver of mice surviving for 2 weeks or more after intravenous inoculation of Tyzzer's organisms, MSK strain, were observed giant cell granulomas with intracellular deposition of mucopolysaccharide and calcium, while bacterial antigen was not detectable. Serum antibody was positive in all cases already at 2 weeks postinoculation and high-titered antibody remained at 9 weeks of infection.

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Four strains of rat sialodacryoadenitis virus isolated in Japan were shown to readily propagate in the LBC cell culture showing marked cytopathic effect with syncytia formation. Viral antigen was demonstrated in the syncytia produced by 4 isolates by indirect immunofluorescence. The LBC cell culture might provide a useful assay system for sialodacryoadenitis virus being difficult to propagate using previously described cell system.

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