The muscles of mastication of the polar bear (Ursus maritimus) and those of the brown bear (U. arctos) were examined by anatomical approach. In addition, the examination of the skull was carried out in the polar bear, brown bear and giant panda (Ailuropoda melanoleuca). In the polar bear, the rostro-ventral part of the superficial layer of the M. masseter possessed the abundant fleshy portion folded in the rostral and lateral directions like an accordion. Moreover, the rostro-medial area of the superficial layer became hollow in the nuchal direction when the mouth was closed. The M. temporalis of the polar bear covered up the anterior border of the coronoid process of the mandible and occupied the almost entire area of the cranial surface. The M. pterygoideus medialis of the polar bear was inserted on the ventral border of the mandible and on the ventral part of the temporal bone more widely than that of the brown bear. As results of our measurements of the mandible, an effect of the leverage in the polar bear was the smallest in three species. In the polar bear, the skull was flat, and the space between zygomatic arch and ventral border of the mandible, occupied by the M. masseter was the narrowest. It is suggested that the muscles of mastication of the polar bear is adapted to the flat skull feature for supplementing the functions.

抄録全体を表示

A-type (atrial) natriuretic peptide (ANP) levels in the auricular cardiocytes and plasma were examined by immunohistochemistry, electron microscopy, and radioimmunoassay in pregnant and lactating mice. Additionally, the cardiocyte ANP mRNA expression was measured by the polymerase chain reaction method. ANP-immunoreactivity (IR) and the number of ANP-granules in the cardiocytes on the 18th day of gestation were greater than those in virgin controls, but the plasma ANP concentration decreased on the 18th day of gestation. On the day of delivery, ANP-IR and the number of ANP-granules in the cardiocytes were decreased compared to those during the pregnancy and to those in virgin controls, and then began to increase continually until the 15th day of lactation. Plasma ANP concentration after delivery was significantly higher than that during pregnancy, and than that in virgin controls, and continued to increase until the 15th day of lactation. Cardiocyte ANP mRNA expression was highest on the day of delivery compared to that in all the other times. In conclusion, these results suggested that the circulating systems of ANP during pregnancy and lactation were regulated differentially.

抄録全体を表示

Specialization of the ganglion cell layer (GCL) was studied by Nissl-staining and axonal tract-tracing methods in chicks and chick embryos. The changes in the retinal area and the cell number in the GCL produced a disparity in the cell density that occurred through the two different processes, cell generation (before embryonic days 10-14, E10-14) and cell loss (after E10-14). One high-density area was found in the retinal fundus on E8 (presumptive central area, pCA) and its density decreased toward the peripheral retina. Another high-density area was found in the dorsal retina on E11 (presumptive dorsal area, pDA). Cell densities of the pCA and the pDA on E11 decreased gradually to 25-30% by P1, and after that they further decreased to 40-60% by P30. The pCA was still identified on P30, but the pDA became very obscure by this age. In contrast, ganglion cell sizes increased 5-7 times in the pCA and pDA from E8 to P30, and increased 12 times in the temporal periphery. The present study suggests that the center-peripheral gradient of cell density results from lager scale of cell genesis in the pCA, but not from lager scale of cell loss in the peripheral retina. However, obscuration of the pDA results from equalization of cell density in cellular degeneration processes.

抄録全体を表示

Annexins are phospholipid-binding proteins and are abundant in the lung. Annexins I and IV, but not II and VI, have been detected in broncholaveolar lavage (BAL) fluids from calves inoculated with Pasteurella haemolytica, the pathogen for calf pneumonia. In this study, BAL fluids from calves with experimental pneumonia induced by inoculation to right lung lobes of bovine herpes virus-1 (BHV-1), the major viral pathogen for pneumonia, were examined for detection of annexins I and IV. Of 6 calves inoculated with BHV-1, annexins I and IV were coincidentally detected in BAL fluids from right lung lobes of 4 calves, but not in BAL fluids from left lung lobes of 6 inoculated calves or those from left and right lung lobes of 3 control calves. Annexin II and VI were not found in any BAL fluids examined. These results, together with previous findings on calves inoculated with Pasteurella haemolytica, suggest that the release of annexins I and IV onto the alveolar surface is an essential event occurring in response to pulmonary infections of BHV-1 and Pasteurella haemolytica.

抄録全体を表示

After physically disrupting cell contacts, apoptosis of bursal cells of Fabricius was induced during in vitro cultivation. The percentage of apoptotic cells increased with incubation time and approximately 70% cells represented apoptosis after 6 hr of incubation. The induction of apoptosis was significantly inhibited by treatment of the cells with ascorbic acid (vitamin C), but not with trolox, a vitamin E analog. An intense DNA ladder pattern was shown at 6 hr post-isolation, which is a biochemical hallmark of apoptosis. Treatment of the cells with ascorbic acid inhibited the DNA fragmentation, but trolox did not. To monitor the intracellular production of reactive oxygen species (ROSs), the intensity of fluorescence emitted from DCFH-DA was measured. The intensity of fluorescence from cells incubated for 0.5-2 hr was approximately 2-fold higher than that from cells at 0 hr. The relative intensity of fluorescence decreased immediately after the addition of ascorbic acid to the cells. The intensity from the cells treated with ascorbic acid was 20-30% of that from the control cells at each incubation time. For trolox, the intensity was 50-70% of that from the control cells at each 1 to 2 hr incubation time. When ROSs-induced lipid peroxidation was assessed using cis-parinaric acid (PnA) as a monitor molecule, lipid peroxidation was found to occur in the control cells after isolation of the bursal cells. Treatment of the cells with trolox reduced lipid peroxidation, but treatment with ascorbic acid enhanced peroxidation.

抄録全体を表示

Lipoprotein lipid and apoprotein concentrations are known to be altered during the acute-phase response. We have previously shown that the serum activity of lecithin:cholesterol acyltransferase (LCAT) and concentration of cholesteryl esters, both constituents of the high-density lipoprotein (HDL) fraction, are reduced in calves inoculated with Pasteurella haemolytica and bovine herpes virus-1, the two major pathogens for calf pneumonia. The concentration of apolipoprotein C-III (apoC-III), a low molecular mass protein component distributed mainly in the HDL fraction, was therefore examined in bacteria- and virus-inoculated calves. An enzyme-linked immunosorbent assay demonstrated that it was decreased by inoculations of Pasteurella haemolytica and bovine herpes virus-1. The decrease was detected as early as 1 day after inoculation in both groups. A decreased serum apoC-III concentration was also observed by immunoblot analysis. It was detected in the HDL fractions from the bacteria- and virus-inoculated calves, and HDL apoC-III concentrations in the inoculated calves were decreased compared with controls. These results, coupled with the previous findings on LCAT activity and the cholesteryl ester concentration, indicate that a decreased HDL concentration is one of the early events occurring during the acute-phase response evoked by infections with Pasteurella haemolytica and bovine herpes virus-1.

抄録全体を表示

Blood samples were collected from 20 sedated captive Eld’s-Brow Antlered deer (Cervus eldi thamin), aged over 1.5 years, to define their mean hematological values (packed cell volume and hemoglobin) and mean plasma biochemical parameters. Male deer had a significantly higher plasma glucose level and aspartate aminotransferase activity than female deer.

抄録全体を表示

MRL/lpr mouse is an established animal model which develops autoimmune diseases including glomerulonephritis, sialoadenitis, hepatitis and inflammatory lung disease. Additionally, it has been reported that lpr strains uniquely accumulate CD3⁺CD4^-CD8^-B220⁺ (double negative, DN) T cells in lymphoid organs leading to lymphadenopathy and splenomegaly. To investigate the role of CD28/CTLA4-B7 pathway in the development of lymphadenopathy and splenomegaly, MRL/lpr mice were treated with soluble form of CTLA4 molecules, CTLA4IgG, which efficiently blocks this pathway. It was demonstrated that (i) the development of DN T cells was independent of the CD28/CTLA4-B7 pathway, (ii) the CD28/CTLA4-B7 pathway was required for the development of lymphadenopathy and splenomegaly, (iii) the CD28/CTLA4-B7 pathway was important for the accumulation of various cell populations in the lymph node and spleen, (iv) composition of the accumulating cell populations was not altered by CTLA4IgG treatment, and (v) activation of conventional T cells and IL-4 production from conventional T cells were the CD28/CTLA4-B7 pathway dependent. Thus, we concluded that the CD28/CTLA4-B7 pathway was required for the development of full-blown lymphadenopathy and splenomegaly in MRL/lpr mice.

抄録全体を表示

Hematological abnormalities were investigated in 13 cats with myelodysplastic syndrome (MDS). Examination of the peripheral blood samples from the 13 cats revealed anemia in 11 cats, leukopenia in 9 cats, and thrombocytopenia in 9 cats. Four cats had pancytopenia (30.8%) and 9 cats had bicytopenia (69.2%). Dysplastic changes of erythrocytes, neutrophils, and platelets in the peripheral blood were found in 5, 10 and 8 cats, respectively. Bone marrow examination of the 13 cats revealed that ratios of blast cells to all nucleated cells (ANC) ranged from 0 to 20%. Ratios of erythroid progenitor cells to ANC were more than 50% in 3 cats and less than 50% in 10 cats. Eosinophils accounted for more than 5% of non-erythroid cells in 10 cats. Dysplastic changes in the granurocytic, erythrocytic, and megakaryocytic cells in the bone marrow were found in 11, 7 and 5 cats, respectively. Dysplastic changes in these cats included giant neutrophils, ring-nucleated neutrophils, binuclear myelocytes, hypersegmented and hyposegmented neutrophils, megaloblastoid erythroblasts, multinucleated erythroblasts, micromegakaryocytes, and segmented multinucleated megakaryocytes. Virological examination indicated the presence of feline leukemia virus antigen in the peripheral blood from all of the 13 cats with MDS. The peripheral blood cytopenias and dysplastic changs in each blood cell lineage in the bone marrow were shown to be important for the diagnosis of MDS in cats.

抄録全体を表示

In 33 dogs with mitral valve insufficiency (MR), assessed as severe by semi-quantitative color flow Doppler echocardiography, regurgitation volumes were measured by the “Proximal Isovelocity Surface Area” (PISA) method. Good correlation (p<0.01, r=0.97) between the regurgitation volumes determined by the “PISA” and pulsed Doppler methods was confirmed. As evaluated by the “PISA” method, regurgitation rates in the 32 dogs with measurable regurgitation volumes ranged from 23 to 73%, with a mean of 51.6 ± 11.8%. Regurgitation volumes ranged from 3.3 to 32 ml, with a mean of 8.4 ± 6.4 ml.

抄録全体を表示

A one-year old castrated male cat was admitted to the hospital with vomiting and diarrhea. Laboratory examination revealed pancytopenia and positive for FeLV antigen. A bone marrow examination indicated necrosis of the nucleated cells. Based on these findings, the cat was diagnosed as bone marrow necrosis. Pancytopenia was effectively treated with corticosteroids. Re-examination of the bone marrow confirmed a recovery of normal hematopoietic cells with a infiltration of many macrophages. It is strongly suspected that the bone marrow necrosis in this case could be associated with a bone marrow suppression due to FeLV infection.

抄録全体を表示

We assessed the change of bone mineral density (BMD) in lactating beagles with dual energy X-ray absorptiometry (DXA) and the preventive effect of 1α-hydroxyvitamin D₃ (1α(OH)D₃) on the BMD. Beagles, two to five years old, were used for detecting the time course change of BMD. Since the coefficient of variation (CV(%)) on detecting lumber vertebral (L2-L4) and tibial BMD by DXA was about 0.5%, DXA was useful to detect the change of BMD in beagles. There was a marked decrease in vertebral BMD during lactational period in the control group. The BMD levels after weaning were found to reverse to the initial level at mating. The same tendency was observed in tibial BMD as vertebral BMD, though the BMD changes were not marked. Beagles were administered at a dose of 0.1 μg/kg of 1α(OH)D₃ three times in a week, and it was found to suppress the decrease in vertebral BMD during the breast feeding period. Also, the administration of 1α(OH)D₃ promoted the prevention of decreased BMD during lactation both in vertebrae and tibiae. Significant effects of 1α(OH)D₃ administration on tibial BMD were not observed. No adverse effects, such as hypercalcemia and hypercalciuria, were observed during the experimental period. Therefore, DXA was useful for detecting the changes of BMD in lactating beagles and the change of BMD was marked in lumber vertebrae, which are rich in trabecular bone. The preventive effect of 1α(OH)D₃ on the decrease of BMD during the lactation period was observed in beagles.

抄録全体を表示

To examine the effect on cell population in hepatocytes of phenobarbital (PB) and other barbiturates, PB, allobarbital (ALB), barbital sodium (BS) and barbituric acid (BA) were given orally to male rats for 7 consecutive days. Although there was no apparent change in non-promoting BA, hepatomegaly was induced by PB, BS and ALB, which are promoters of hepatocarcinogenesis. In PB- and BS-treated livers, hepatomegaly was attributable to hepatocyte proliferation and enzyme induction. In ALB-treated liver, it was attributable to enzyme induction. The level of cell proliferation was reduced to less than the control values following withdrawal of PB, ALB and BS. It seemed that the degree of suppression of cell proliferation following withdrawal of these compounds correlated to the degree of cell proliferation (PB>BS>ALB) during treatment. In PB-treated liver, apoptosis was induced during treatment, serving to eliminate the excess of hepatocytes. This suggests that short-term administration of PB neither induced suppression of apoptosis nor disturbed homeostasis of hepatocyte populations.

抄録全体を表示

A melanotic neurofibroma in a steer was investigated histologically, immunohistochemically and ultrastructurally. A very large tumor mass was located in the region of the head and right cheek. The tumor tissue consisted of an admixture of cells resembling Schwann cells and spindle-shaped cells, and they frequently contained melanin granules. Neoplastic Schwann cells were positive for S100 protein, with variation in intensity of staining, but most spindled cells were S100 negative. The tumor cells displayed ultrastructural features similar to those of Schwann cells or perineurial cells. The presence of melanosomes in varying stages of melanization in both cell types suggests that they have a common origin. This is a tumor of neural crest origin showing schwannian and perineurial differentiation, with ectopic production of melanin granules.

抄録全体を表示

Effects of perineural capsaicin (CAPS) treatment on compound action potentials of the superior laryngeal nerve (SLN) afferents were studied in 6 sevoflurane-anesthetized dogs. Perineural CAPS (100 μg/ml) to the bilateral SLNs reduced (P<0.01) the peak and integral amplitudes of the C-wave of the compound action potential. By contrast, the perineural CAPS had no effect on the A-wave component (P>0.05). Removal of the perineural CAPS recovered the C-wave to pretreatment level. The perineural CAPS treatment selectively blocks C-wave compound action potentials of the SLN afferents, providing a useful tool for studies of laryngeal C-fibers in respiratory physiology.

抄録全体を表示

The effects of orchidectomy on bone metabolism in male beagle dogs were examined using twelve 2-year-old dogs that were orchidectomized. The dogs’ bilateral iliac bones, double-labeled with tetracycline and calcein for the histomorphometry, were obtained from three dogs prior to orchidectomy and at 3, 6, 9, and 12 months afterwards. The serum biochemical constituents related to bone metabolism were examined before and every month after orchidectomy. Between 1 and 6 months after orchidectomy, the value of serum testosterone decreased (1 month), while the levels of parathyroid hormone, calcitonin, total calcium, osteocalcin, and alkaline phosphatase activity increased significantly, indicating a high bone turnover. The mean trabecular thickness and the fraction of labeled osteoid surface decreased significantly 3 months after orchidectomy, but other histomorphometric parameters were unchanged. In the period 7-12 months after orchidectomy, the parathyroid hormone level increased ever and above that of the first 6-month period, while the levels of calcitonin, osteocalcin, alkaline phosphatase activity, and phosphorus decreased. The bone volume, mean trabecular thickness, and the fraction of labeled trabecular surface decreased significantly compared with the pre-orchidectomy values. These findings indicate an imbalance in bone metabolism ( i.e. bone resorption > bone formation). These results indicate that a loss of bone volume accompanied the fall in sex hormone levels following orchidectomy and suggest that the orchidectomized dog is available as an animal model for studying osteoporosis caused by hypogonadism and the decline of sex functions in men.

抄録全体を表示

In this study antemortem evaluation of equine flexor tendons - the superficial digital flexor tendon and the deep digital flexor tendon - using magnetic resonance (MR) images was performed. Postmortem flexor tendons were used to prepare the slice positions, coil and body positions for MR imaging. It was possible by this method to take antemortem MR images of equine limbs that distinguished features as well as postmortem images described in previous studies. The total time of antemortem scanning was about 40 min. This study is the first to report antemortem MR images in horses.

抄録全体を表示

Sea turtles are considered to be endangered species. A depressed fracture of a 35 kg green sea turtle was treated surgically. Isoflurane was used for induction and maintenance of anesthesia. Slow induction of and slow recovery from anesthesia was remarkable. After the operation, there was an improvement of general status, but head tilt and weakness of the left limbs persisted. As the turtle did not eat, force feeding using stomach tube was performed. The turtle died at about 6 months after the surgery.

抄録全体を表示

This study was conducted to purify a tissue inhibitor of metalloproteinase (TIMP)-1 in a serum-free medium conditioned with bovine oviduct epithelial cells (BOEC) and to evaluate its effect on development of “HanWoo” (Bos taurus coreanae) embryos to the blastocyst stage. In the first study using SDS-PAGE electrophoresis, the presence of 32 kDa proteins, which contains TIMP-1, was detected in the medium conditioned with BOEC, and TIMP-1 was then purified from the medium by gel filtration and HPLC techniques. When examined TIMP-1 secretion, fluorescent foci indicating the secretion of TIMP-1 were found after stained BOEC with fluorescein isothiocyanate. In the next experiment, two-cell embryos derived from in vitro-fertilization were cultured in a serum-free medium, to which 0, 1.25, 2.5 or 5 μg/ml of purified TIMP-1 was supplemented. More (P<0.05) embryos developed to the morula and blastocyst stages after the addition of 2.5 μg/ml to culture medium than after no addition. In conclusion, our data indicate that BOEC secrete TIMP-1 and this glycoprotein promotes the prehatched development of “HanWoo” embryos derived from in vitro-fertilization.

抄録全体を表示

Ejaculated sperm collected from 12 beagle dogs were incubated in canine capacitation medium (CCM), supplemented with 5 μg/ml chondroitin sulfate A (CS), 5 μg/ml hyaluronic acid (HA), or 5 μg/ml heparin (HP) for 7 hr at 38°C in a 5% CO₂ in air atmosphere to investigate the effects of glycosaminoglycans (GAGs) on dog sperm capacitation. The percentages of motile sperm, hyperactivated sperm (%HY), and acrosome-reacted sperm (%AR) in all media were examined after 4 hr and 7 hr of incubation. The oviducts and uteri of 9 anestrous and 18 estrous beagle bitches were removed under halothane inhalation anesthesia to measure the total GAG amounts in oviductal and uterine fluids. The lumens of the ampulla of the oviducts, isthmus of the oviducts, and the uterine horns were each flushed with 1 ml HEPES-EDTA fluid. Total GAG amounts in the flush fluids obtained were measured with a spectrophotometer. Sperm motility (51-59%), %HY (79-86%), and %AR (31-36%) in CCM supplemented with CS, HA, or HP were significantly higher after 7 hr of incubation than when incubated in CCM without GAGs (P<0.01 or 0.05). The mean total GAG amounts in the fluids from the ampulla and isthmus of the oviducts and the uterine horns in the estrous bitches were higher than in the anestrous bitches. These results indicate that GAGs in the oviductal and uterine fluids in estrous bitches are associated with in vivo sperm capacitation.

抄録全体を表示

Bovine in vitro matured and fertilized oocytes were cultured for 153 hr in groups of 3 or 30 in 30 μl of modified synthetic oviduct fluid medium supplemented with amino acids. The concentration of ammonium in culture medium at 153 hr of culture was significantly decreased by medium change at 72 hr of culture. However, regardless of embryo density, medium change had no beneficial or detrimental effect on the development of bovine embryos. Increase in the development to blastocysts and production of ammonium were observed when embryos were cultured in groups of 30. These results indicated that the ammonium concentration detected in this culture system has a negligible effect on the development of bovine embryos to blastocysts.

抄録全体を表示

The effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. The viruses used were four enveloped viruses (vesicular stomatitis virus, African swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (SVDV) and African horse sickness virus (AHSV)). Chlorine was effective against all viruses except SVDV at concentrations of 0.03% to 0.0075%, and a dose response was observed. Iodine was very effective against all viruses at concentrations of 0.015% to 0.0075%, but a dose response was not observed. Quaternary ammonium compound was very effective in low concentration of 0.003% against four enveloped viruses and AHSV, but it was only effective against SVDV with 0.05% NaOH. Electron microscopic observation revealed the probable mechanism of each disinfectant. Chlorine caused complete degeneration of the viral particles and also destroyed the nucleic acid of the viruses. Iodine destroyed mainly the inner components including nucleic acid of the viruses. Quaternary ammonium compound induced detachment of the envelope of the enveloped viruses and formation of micelle in non-enveloped viruses. According to these results, chlorine and iodine disinfectants were quite effective against most of the viruses used at adequately high concentration. The effective concentration of quaternary ammonium compound was the lowest among the disinfectants examined.

抄録全体を表示

The nucleotide sequences of the phosphoprotein (P) of canine distemper virus (CDV) strains isolated between 1992 and 1996 in Japan were determined. This is the first report of the complete sequences of the P genes of recently prevalent CDV strains. The deduced amino acid sequences of the P, C and V proteins showed that in the new Japanese isolates, these proteins have approximately 93%, 90-91% and 92% identities with those of the Onderstepoort vaccine strain, respectively. The predicted functional regions were conserved. RNA editing resulting in a shift to the open reading frame (ORF) of the V protein was shown to occur with the same efficiency in both the field isolates and vaccine strain.

抄録全体を表示

The present examination was conducted to determine if the pigs infected with one strain of porcine reproductive and respiratory syndrome virus (PRRSV) would be protected against a subsequent homologous virus challenge. Sixteen 4-week-old SPF pigs were assigned to 2 experimental groups A and B. The pigs in group A were inoculated with 10^6.5 TCID₅₀ of PRRSV by intranasal route. On 77 days post-inoculation (PI), pigs in groups A and B were similarly inoculated with same virus. After the secondary inoculation, the pigs in group A didn’t show any clinical sign including pyrexia and reduction of white blood cell (WBC) number. Viremia was detected only on 3 days PI with low virus titer and any virus was not recovered from serum and tissues at the time of necropsy on 14 or 28 days PI. In contrast, pigs in group B showed pyrexia for 14 days and reduction of WBC number on 3 days PI. Viremia was detected between 3 and 28 days PI, and virus was isolated from several tissues of all pigs. These results indicate that previous exposure to PRRSV can prevent development of clinical signs and reduce virus proliferation in pigs after subsequent infection with the homologous PRRSV.

抄録全体を表示