Marek's disease (MD) is a lymphoproliferative disease of chicken, which is characterized by malignant T cell-lymphoma formation. This disease can be effectively prevented by vaccination with attenuated MD virus (MDV), apathogenic MDV or herpesvirus of turkey. MD vaccines are ones of a few vaccines which can prevent virus-induced tumor among mammalian and avian species. To determine the roles of T cell subsets in the protection mechanism, chickens vaccinated with an attenuated MDV (CVI988) were depleted of either CD4⁺ or CD8⁺T cells by neonatal thymectomy and injections of monoclonal antibodies against chicken CD4 or CD8 molecules and then challenged with an oncogenic MDV. These birds were effectively protected from MDV-induced tumors. However, virus titers in CD4⁺T cells, which are the main target cells for MDV-latent infection and subsequent transformation, were much higher in CD8-deficient vaccinated chickens than in untreated vaccinated chickens at the early stage of the latent phase. These results suggested that CD8⁺T cell responses induced by the MD vaccine are essential for anti-virus but not anti-tumor effects. Here, we will discuss how the attenuated vaccine prevents chickens from lymphoma-formation by an oncogenic MDV.

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The present study was aimed to examine the effects of follicle-stimulating hormone (FSH) on cell division of Sertoli cells from rat fetal testes and on the kinetics of 2 kinds of intermediate filaments, cytokeratin and vimentin, which comprise the cytoskeleton of Sertoli cells. Testes from rat fetuses of different ages (from day 15 to day 17 of gestation ) were cultured for 48 hr, with or without added FSH. In 15-day testes, FSH influenced neither cell division of Sertoli cells nor kinetics of intermediate filaments. In 16-day testes, FSH promoted cell division of Sertoli cells and kinetic differentiation of intermediate filaments distributed toward the lumen of the seminiferous tubules. These findings suggest that 16-day testes in culture can respond to FSH in a fashion that cell division of Sertoli cells is promoted and that intermediate filaments increase in number and change in intracellular distribution. It is concluded that FSH influences both proliferation and morphological differentiation of Sertoli cells.

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We measured adult mandibles of Ryukyu wild pigs from Amami-Oshima, Kakeroma, Okinawa, Ishigaki and Iriomote Islands. The size cline was not statistically recognized among the populations of Nansei Islands. The Ishigaki population was significantly larger than Iriomote one in mandible length. Some measurement ratios indicated that the ramus is enlarged laterally and that the body of mandible is dorso-ventrally developed in Ishigaki and Iriomote populations. The Amami-Oshima mandibles were relatively smaller than those of Okinawa and Iriomote populations in length item of body of mandible. These results will contribute to the zoo-archaeology on the historical change of size and shape in the island populations, and to the evolutionary biology on the morphological adaptation of this animal.

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To examine whether a lymphoid leukosis (LL) cell line releases an LL-specific avian leukosis virus (ALV) or not, two viral materials, culture fluid and a concentrated viral material from an LL-cell line, were inoculated into a total of 74 day-old chicks of line 15I in 5 experiments. Spectrum of diseases induced, their incidence and incubation periods to onset were examined. Fifteen chicks were inoculated with the culture fluid and 9 (60%) developed ascites [59-119 days post inoculation (dpi); geometric mean (GM) of dpi, GM: 89.6)], but LL was not induced in any chicks inoculated. Fifty-nine chicks were inoculated with the concentrated viral material and LL was recognized in 13 (22.0%) (27-74 dpi; GM: 48.4), ascites with LL in 11 (18.6%) (34-75 dpi; GM:41.3), ascites alone in 21 (35.6%) (32-83 dpi; GM: 48.2), erythroblastosis in 2 (3.4%) (70-102 dpi; GM: 84.5), and other diseases in 12 (20.3%) (43-102 dpi; GM: 61.8). LL lesions were frequently observed in the liver, spleen, kidneys, bursa of Fabricius (bursa), bone marrow and gonads. Mild lymphocytic foci in some visceral organs and perivascular cuffing in the central nervous system were observed mainly in several chicks diagnosed as having complication of ascites with LL or other diseases. In addition to these lesions, atrophy of bursa and thymuses was recognized in them. No antibodies against Marek's disease virus (MDV) and reticuloendotheliosis virus were detected in 36 sera taken from the chicks inoculated with the concentrated viral material. Serotype 2 MDV was isolated from the buffy coat of some inoculated chicks. These results suggest that the properties of ALV inoculated and immunosuppression caused by inoculation with high doses of ALV are involved in rapid induction of LL and expression of pathogenicity of serotype 2 MDV released from the LL cell line and included in the viral inoculum. This is the first report describing the rapid induction of LL and ascites in chicks.

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A vaccine was prepared from a NaOH-extracted antigen of the Kyoto strain (serovar 2) of Erysipelothrix rhusiopathiae (E. rhusiopathiae) with an oil adjuvant, and was injected twice at 3-week intervals into SPF pigs and conventional pigs with maternal antibodies. After the second vaccination, IgG-GA titers of immunized SPF pigs were more than 256-fold at 3 weeks, and immunized pigs with maternal antibodies were 64-fold at 7 weeks. The pig with maternal antibodies vaccinated once with live vaccine had less than 4-fold titers. The ELISA antibody titers which were measured by using the NaOH-extracted antigen showed similar transition to the IgG-GA antibody titers. All immunized pigs and nonvaccinated control pigs were challenged with the strains Fujisawa (serovar 1a) or Saitama-1 (serovar 2). After challenge exposure, all pigs immunized with the NaOH-extracted vaccine showed no clinical signs and survived, and the pig immunized with the live vaccine had a local rhomboidal lesion at the site of the injection. Nonvaccinated pigs developed typical symptoms of E. rhusiopathiae infection and one of them died. After the autopsy, the challenge strains were not recovered from the main organs except tonsils of the pigs immunized with the NaOH-extracted vaccine. These results indicated that the NaOH-extracted vaccine induces a protective effect in pigs with maternal antibodies as well as in SPF pigs negative for such antibodies, and that 67-64, 62-60 kDa proteins in the NaOH-extracted antigen play an important role in protecting against E. rhusiopathiae infection.

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A total of 170 β-hemolytic streptococci isolated from lesions in slaughtered pigs during 1988 to 1995 were identified by biochemical and serological examinations. Of these, 132 strains (77.6%) were Streptococcus (S.) dysgalactiae and 38 strains (22.4%) were S. porcinus. The largest serological group of streptococci was group C (78 strains, 45.9%), followed by group L (43 strains, 25.3%), group U (14 strains, 8.2%), group G (11 strains, 6.5%), group E (5 strains, 2.9%), and group P (5 strains, 2.9%). Most of isolates from endocarditis (61 strains) and arthritis (25 strains) were group C S. dysgalactiae, but about 33.3% of the isolates from lymphadenitis were group L S. dysgalactiae (28 strains), followed by group C (14 strains, 16.7%), group U S. porcinus (14 strains, 14.3%), and group G (10 strains, 11.9%).

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To elucidate the pathogenesis of halothane-induced hepatopathy, the changes of hepatic tissue phospholipid peroxidation, malondialdehydes (MDAs), and antioxidative enzyme activities were examined in the portal vein arterialized dogs with halothane inhalation. In group A, which was given halothane inhalation under the hepatic blood flow volume less than 10% of pre-operation volume designated as a hypoxic condition, peroxidized phosphatidylcholine (PC), and free and protein-bound MDA levels significantly increased after inhalation. Although the level of protein bound MDA in group C, given hypoxic condition alone, also increased during the experimental period, the response of this was smaller than that in group A, suggesting that the halothane inhaltation enhanced free radical generation under the hypoxic condition. In contrast, no significant changes of these levels were observed in groups B and D, both of which were supplied with sufficient hepatic oxygen as the normoxic condition. In addition, the significant negative correlations between hepatic oxygen supply and total or protein-bound MDA were observed in only halothane inhaled group. These findings suggested that the cause of halothane-induced hepatopathy is closely related to free radicals mainly generated from halothane anaerobic metabolism under the hypoxic condition.

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To elucidate mechanisms of free radical-induced neuronal cell death, lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS), three antioxidative enzyme activities (superoxide dismutase, glutathione peroxidase, and catalse), and cytosolic free Ca²⁺ (Ca²⁺i) were examined in rat hippocampus-derived cells (HV16-4) exposed to free radicals generated by a hypoxanthine-xanthine oxidase system. The viability of cells decreased with an increase in numbers of free radical positive cells in a dose-dependent manner of xanthine oxidase. The protein-bound TBARS did not change, whereas free TBARS increased at 135% of initial value. No remarkable change was observed in three antioxidative enzyme activities. On the other hand, Ca²⁺i increased after exposure followed by cell death. Furthermore, the addition of Co²⁺, a nonspecific Ca²⁺ channel blocker, delayed the increase of Ca²⁺i and subsequent cell death. These findings suggested that the influx of Ca²⁺ played a crucial role for HV16-4 cell death induced by free radicals.

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We assessed the effect of nerve growth factor (NGF) on Fc gamma receptor (FcγR) expression on murine monocyte-macrophage J774A.1 cells. Flow cytometric analysis showed that treatment with various doses of NGF led to a rapid increase of FcγRI and FcγRII/III expression in a dose-dependent manner. Northern blot analysis with digoxigenin-labeled oligonucleotide probes demonstrated that NGF induced a marked increase in mRNA synthesis of FcγRI and FcγRII, but not FcγRIII. Since pretreatment with K-252a, a tyrosine kinase inhibitor, inhibited the stimulatory effect of NGF completely, the FcγR expression augmented by NGF may be mediated through p140^trk with a tyrosine kinase domain. These results suggest that NGF may be a novel cytokine that is able to increase FcγRI and FcγRII expression on macrophages.

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Significant decrease of serum vitamin A (V.A) level in 4 out of 5 Japanese Black beef steers on day 7 after introduction was described in the present study. The feeder steers were fed the diets containing much more V.A than they required. In the farm where they were introduced, the productivity was high and the frequency was low in bovine cases of death and disease. The herd management; i.e. feeding method and environment of the farm were properly arranged. Results obtained from blood serum analyses revealed that health and nutritional status of the feeder steers were good on the day of introduction. The feeder steers, clinically healthy on the day of introduction, manifested mild bronchitis and diarrhea on days 2 and 10 after introduction, respectively, and slightly decreased dietary intake on both days. Serum V.A levels of the feeder steers were within the normal range. However, significantly decreased serum V.A level was detected in 4 feeder steers out of 5 on day 7 after introduction. This may be attributed to stress-increased V.A consumption rather than the decreased V.A intake.

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Vascular changes, the angioarchitecture of renal glomerular fine vessels in early diabetic KK-A^y mice of 4 months of age were examined by scanning electron microscopy of corrosion casts. Histologically, enlargement of glomeruli and dilation of glomerular capillaries were found. In resin cast specimens, glomeruli with diabetes were larger than normal, and an increase in diameter of the glomerular vessels was found in diabetic mice. No capillary proliferation, distortion of glomerular vessels and destruction of glomerular capillary loops were found in diabetic mice. The increased vascular diameter may explain the increase in blood flow in the glomeruli, affecting kidney function in early diabetes.

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The genomic DNA encoding bovine Thyrotropin-Releasing Hormone Receptor (TRHR) was isolated from a bovine (Holstein) genomic library. Using PCR fragments of bovine candidate TRHR Transmembrane domain (TMD-III-IV) and C-terminus domain of mouse TRHR cDNA as probes, 9 × 10⁵ plaques were screened to obtain several clones each containing the N-terminus or C-terminus domain. The bovine TRHR gene encoded 398 amino acids and has a long intron. The identity of the deduced amino acid sequence of bovine TRHR exceeded 88% that of mouse, rat or human. RT-PCR analysis indicated TRHR mRNA to be expressed in the pituitary and brain.

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We tried to develop an experimental system for quantifying piroplasm transmission in Theileria sergenti infection using a SCID mouse model, of which red blood cells (RBC) had been substituted with bovine (Bo). A mouse hybridoma cell producing antibody against Holstein RBC was established for distinguishing Holstein RBC from Japanese Black RBC by a immuno-staining method. T. sergenti piroplasms in RBC were stained by 4',6-diamidino-2-phenylindole. With the aid of these techniques the piroplasm transmission from one to another race of Bo-RBCs could successfully be quantified in SCID mice.

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To investigate the pathogenesis of porcine serum (PS)-induced liver fibrosis in rats, two experiments were carried out, taking into consideration of hypertension and vascular changes. In Experiment I, spontaneous hypertensive rats (SHRs), two-kidney, one clip hypertensive F344 rats (2K1C rats), and normotensive F344 rats were given an intraperitoneal injection of PS of 0.5 ml twice a week for 8 weeks. Histopathological, immunohistochemical, and electron microscopical examinations were performed on the liver from each rat. Histological features of liver fibrosis in hypertensive and normotensive rats were essentially identical. However, in the PS-treated SHRs, 2 of 5 animals showed the most severe fibrosis in all PS-treated groups. Electron microscopically, degranulated mast cells, eosinophils, and macrophages engulfing apoptotic cells were rarely observed in the late stage of fibrous septa (FS) in the PS-treated SHR liver. In Experiment II with normotensive F344 rats, histopathological features of early FS in the liver were compared with those of late FS observed in Experiment I using serial sections, and we found that FS developed along the wall of newly formed vessels to connect between neighboring central veins. However, the effect of hypertension on this fibrosis could not be clearly demonstrated in the present study using SHRs and 2K1C rats.

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To study the underlying morphological changes of presbycusis, cochlea and cochlear nuclei from twenty three dogs, ranging in age from 3 days to 17 years, were examined histologically. Dogs used in this study were house dogs kept in an environment similar to that of humans. Four types of histological changes reported in human presbycusis, that is, loss of spiral ganglion cells, atrophy of the organ of Corti, atrophy of the stria vascularis, and thickening of the basilar membrane were observed in dogs. The changes were prominent at the base of the cochlea. Less intense changes were also observed in the apex of the cochlea. The degree of these changes appeared to progress as a function of age. All four types of changes with varied intensity were found in all dogs over 12 years old. In addition to the changes in the cochlea, cochlear nuclei changes including nerve cell loss, astrogliosis and ubiquitin deposition were found in dogs over 10 years old. Hearing dysfunction was accompanied by the morphological changes, though the degree of the hearing dysfunction did not always parallel to that of morphological changes. The morphological changes seen in the cochlea and cochlear nuclei of dogs were qualitatively and quantitatively similar to those reported in aged humans, indicating that otopathologic changes in the inner ear may be due to aging plus exposure to certain environmental ototoxic factors.

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An outgrowth on the left anteriothoracic region behind the elbow joint was seen in a free living Zebra at the time of postmortem examination. The covering skin was ulcerated, nodular, hard with multiple fistula containing yellowish pus. A pure culture of coagulase positive Staphylococcus aureus was isolated from the deep tissue. Histopathology revealed pyogranulomatous dermatitis characterized by eosinophilic amorphous grains including bacterial colonies. This is the first report of cutaneous staphylococcal granuloma in Zebra in Zambia.

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This study has demonstrated the power spectral analysis of heart rate variability in a horse with atrial fibrillation. A large peak in the high frequency (HF) area of the power spectrum appeared in the horse. Hourly heart rate, the low frequency (LF) power, the HF power, and LF/HF ratio were almost constant during the recording period. The values of HF and LF power in the horse with atrial fibrillation were much larger than those in normal horses. The normalized unit of HF (HF n.u.) was much larger than that of LF (LF n.u.). Furthermore, the LF/HF ratio was very small in the horse. These results suggest that the ventricular rhythm has a respiratory related periodicity in the horse with atrial fibrillation and the predominant parasympathetic activity may modulate the intrinsic behavior of the atrioventricular node during atrial fibrillation.

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The purpose of this experiment is to confirm the effects of the descending pathway from the lateral vestibular nucleus (LVN) on rhythmic discharges induced by stimulation of the mesencephalic locomotor region (MLR) in the decerebrated cat. The experiments were performed on 18 adult cats (2.5-4.0 kg) of either sex. The rhythmic discharges produced by the MLR stimulation were recorded from hindlimb extensor muscle (LGS: lateral gastrocnemius and soleus) and flexor muscle (PBST: posterior biceps and semitendinosus) nerves. The LVN stimulation influenced the amplitude and interval of the rhythmic discharges in both extensor and flexor muscle nerves.

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Pretreatment of primary cultures of rat hepatocytes with sodium diethyldithiocarbamate (DDTC) for 15 min prior to exposure to K₂Cr₂O₇ resulted in a marked decrease in dichromate-induced cytotoxicity, as evaluated by the leakage of lactate dehydrogenase, and in lipid peroxidation, as monitored by malondialdehyde formation. In addition, pretreatment with DDTC attenuated the suppression of the level of vitamin E attributed to K₂Cr₂O₇. However, DDTC pretreatment had no effect on the cellular levels of glutathione or vitamin C or on the activity of the glutathione reductase, glutathione peroxidase, superoxide dismutase or alkaline phosphatase suppressed by dichromate. Under the same experimental conditions, cellular uptake or distribution of chromium was not affected by DDTC. These results indicate that the protective effect of DDTC on chromium (VI)-induced cytotoxicity as well as lipid peroxidation may be associated with the level of nonenzymatic antioxidants such as vitamin E.

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We have developed an interlocking intramedullary nail method for the treatment of femoral and tibial fractures and used this method for the treatment of 7 cats and 6 dogs with these fractures. The interlocking nails, with a diameter of 4-6 mm and length of 60-140 mm, have holes at 10 mm intervals for screwing. The nail placed on the insertion device was inserted into the marrow cavity from the end of the fractured bone in the usual procedures for intramedullary fixation, then fixed by screws at the distal and proximal ends with a jig which was also attached to the insertion device. Animals were able to bear weight on the treated legs within three days, and the prognosis was excellent.

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The effect of selenium (Se) supplementation to the diet on the plasma progesterone concentration was investigated in non-lactating and non-pregnant cows. Italian ryegrass wafers and concentrates, with or without 0.5 ppm of Se, were fed to cows at a maintenance level. The plasma Se concentrations in the each treatment were 0.047 ppm (-Se) and 0.081 ppm (+Se), respectively. Se supplementation did not affect the length of the estrous cycle, but it did increase the concentration of plasma progesterone in the estrous cycle (P<0.001). These results suggest the possibility that Se contributes to the progesterone production of corpus luteum.

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This study serves to further define the capabilities of the whole embryo culture system using the well-known teratogen, 5-fluorouracil (5-FU), an antineoplastic agent. An initial in vivo study was performed whereby pregnant rats were injected intraperitoneally with 10-30 mg/kg 5-FU on day 9 of gestation. On day 20 of gestation, the effects of this drug on the growth and development of embryos were evaluated. The number of externally malformed fetuses increased in a dose-related manner, and the most common defect was micro-/anophthalmos in fetuses of dams treated with 5-FU. Growth retardation was also noted in the 5-FU treated groups. An in vitro study was performed in which drug concentrations were varied (0.15-0.30 μg/ml). Externally abnormal embryos were observed in whole embryo culture system from embryonic day 9 to 11. The most common defect was hypoplastic optic vesicles. In the whole embryo culture system, crown-rump length, somite number, protein contents, and morphological score were decreased in a dose-dependent fashion. Finally, histological evaluation and observation of the pattern of cell death of the optic vesicle of 11-day-old embryos in in vivo and in vitro were performed. These parameters revealed no differences in response between in vivo and in vitro embryos treated with 5-FU, suggesting that the whole embryo culture system was an appropriate model for developmental toxicity studies of 5-FU.

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A pseudorabies virus (PRV) glycoprotein-mixed vaccine was prepared by heparin-affinity chromatography from PRV-infected PK-15 cell lysates. In our previous study [8], the trial vaccine was induced protection with suppression of virus shedding in one-month-old pigs and generation of cytotoxic T lymphocyte (CTL) response in mice. In this study, the effect of the trial vaccine on suppression of both virus shedding and reproductive failure in pregnant sows was examined. Three sows were vaccinated twice until one week before mating. Each of them was infected intranasally with 10⁶ TCID ₅₀ of PRV on day 28, 54, or 85 after mating, respectively. Three other sows were also mated and challenged at the same time as the respective control. The vaccinated sows produced virus-neutralizing antibodies. Sows with high level of VN antibody lowered the level and period of virus shedding after challenge. The maximum level of shed-virus titers in vaccinated sows were 10^1.25 to 10³ times lower than controls. Vaccinated sows shed virus for 1 or 5 days, while controls shed for 8, 9, or 12 days. No abortion or stillbirth was observed in vaccinated sows during pregnancy. On the other hand, control sow challenged at a late stage of pregnancy showed abortion and stillbirth. The results obtained here indicate that our trial vaccine is effective to prevent reproductive failure by pseudorabies virus.

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Infection of the type II feline infectious peritonitis virus (FIPV) strain 79-1146 to primary feline alveolar macrophages and human monocyte cell line U937 was enhanced by the sera of cats experimentally infected with the 79-1146 strain, but not those of cats infected with KU-2 or UCD-1 strain of type I FIPV. The experiments using sera of cats with feline infectious peritonitis (FIP) and of cats naturally infected with feline coronavirus (FCoV) revealed that infection of the FIPV 79-1146 strain to the U937 cells was enhanced only by the sera of cats infected with type II FIPV or feline enteric coronavirus. The samples positive for antibody-dependent enhancement (ADE) activity had high neutralizing antibody titers against the FIPV 79-1146 strain and the samples negative for ADE activity had low neutralizing antibody titers. These findings support the previous results where a monoclonal antibody with neutralizing activity had high ADE activity, suggesting that there was a close relationship between the neutralization and enhancement sites. And then it is also suggested that ADE of infection is likely to be induced by re-infection with the same serotype of virus in type II FIPV infection. Furthermore, U937 cells are considered useful and can be substituted for the feline macrophages for determining ADE of FIPV-infection.

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We isolated porcine cytomegaloviruses (PCMVs) from lung samples of fattening pigs collected in the slaughter houses of 4 prefectures of Japan. Seven isolates were obtained and used for a comparison of serological characteristics by ELISA. J1, the first field isolate in Japan, and B6 which was isolated in the UK were also used in the study. The serological relationships between the isolates were analysed by the method of Archetti and Horsfall. OF1 showed serological differences with Chiba2 and Hiroshima. Differences were also observed between Chiba2 and ChibaC, ChibaC and Kagawa. B6 showed differences with OF2, Chiba3, ChibaC and Hiroshima.

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