The calcium binding protein calbindin D-28k (CB) plays an important role in modulating the activity of neurons in the dentate gyrus. We observed CB immunoreactivity in the dentate gyrus of dogs of various ages (German shepherds). In the 1-year-old group, CB immunoreactivity was detected in almost all of granule cells with poor processes. In the 8-year-old group, the number of CB-immunoreactive (+) neurons in the granule cell layer was significantly reduced (73.2% vs. 1-year-old group), while CB+ cell bodies and fibers were well developed. In the 10-year-old group, the number of CB+ neurons was further reduced by 31.3% when compared to that in the 1-year-old group. This finding demonstrates that the number of CB+ neurons decreases in the aged dog brain and this may be associated with reduction of function in the dentate gyrus.
Seventeen isolates of Newcastle disease virus (NDV) were obtained from various prefectures in Japan during the years 2001-2007 and were genotypically analyzed by the reverse transcriptase-polymerase chain reaction (RT-PCR) method coupled with direct sequencing. These NDV isolates were classified into three genetic groups that had been reported previously, namely, genotypes I, VI and VII. The isolate from an aigamo duck was classified into genotype I with isolates mainly from waterfowl. All isolates from pigeons were classified into genotype VI, the predominant genotype responsible for most Newcastle disease outbreaks in pigeons. The isolate from a pet bird was classified into genotype VI, distinct from the remaining viruses in genotype VI. All isolates from chickens were classified into genotype VII, the predominant genotype responsible for most Newcastle disease outbreaks in the East Asian countries. Among the isolates from chickens, isolates after 2002 were genetically most closely related with isolates in Korea. The single isolate from a wild cormorant was also classified into genotype VII, although it was different from the recent NDV epidemic strain in Japan.
In this study, we examined the antimicrobial susceptibility of 16 Salmonella Typhimurium isolates obtained from horses, and applied several genetic methods, namely polymerase chain reaction (PCR) for detecting class 1 integrons, multiplex PCR for detecting multidrug resistant S. Typhimurium definitive phage type 104 (MR-DT104), and fluorescent amplified-fragment length polymorphism (FAFLP). Seven isolates with an ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline (ACSSuT) type resistance pattern, harbored two class 1 integrons with sizes of 1.2 and 1.0 kb, and were identified as DT104 by bacteriophage typing. These isolates also showed a typical MR-DT104 amplification pattern, which was positive for flost, spvC, invA and int, in multiplex PCR. In the FAFLP analysis, the equine DT104 isolates and the previously reported ACSSuT-type resistant bovine isolates, which were also isolated in Hokkaido were included in the same genetic cluster. Our results retrospectively indicate that MR-DT104 infection has existed in horses in Japan at least since 1996, and it was suggested that there is a highly epidemiological relationship between the equine MR-DT104 isolates and certain multidrug resistant bovine isolates in the same area.
To clarify the behavioral profiles of 9 feline purebreds, 2 Persian subbreeds and the Japanese domestic cat, a questionnaire survey was distributed to 67 small-animal veterinarians. We found significant differences among breeds in all behavioral traits examined except for "inappropriate elimination". In addition, sexual differences were observed in certain behaviors, including "aggression toward cats", "general activity", "novelty-seeking", and "excitability". These behaviors were more common in males than females, whereas "nervousness" and "inappropriate elimination" were rated higher in females. When all breeds were categorized into four groups on the basis of a cluster analysis using the scores of two behavioral trait factors called "aggressiveness/sensitivity" and "vivaciousness", the group including Abyssinian, Russian Blue, Somali, Siamese, and Chinchilla breeds showed high aggressiveness/sensitivity and low vivaciousness. In contrast, the group including the American Shorthair and Japanese domestic cat displayed low aggressiveness/sensitivity and high vivaciousness, and the Himalayan and Persian group showed mild aggressiveness/sensitivity and very low vivaciousness. Finally, the group containing Maine Coon, Ragdoll, and Scottish Fold breeds displayed very low aggressiveness/sensitivity and low vivaciousness. The present results demonstrate that some feline behavioral traits vary by breed and/or sex.
On Misaki peninsula, Japan, fecal samples were collected from 14 Misaki stallions at monthly intervals for 12 consecutive months. The fecal testosterone concentration was measured by radioimmunoassay. We examined monthly fecal testosterone hormone patterns and the relationship between fecal testosterone concentration and breeding season and later harem size. Marked monthly variations in fecal testosterone concentration were observed. The fecal testosterone concentration began rising in March; the highest mean monthly concentration, 2.87 ± 0.18 ng/g, was found in April, and the level remained elevated until the end of August and thereafter decreased. A significant correlation was found between the fecal testosterone concentrations and harem size in both the breeding and non-breeding season among the 14 stallions. It is therefore possible that the testosterone levels in feces, instead of blood, correlate very well with harem size in Misaki stallions. Our findings emphasized that the fecal testosterone concentration can be a powerful indicator for monitoring of endocrine status in wild stallions.
The purpose of this study was to investigate whether intensive insulin treatment of dogs suffering from type 1 diabetes mellitus, resulting in tight glycemic control, could be reflected by changes in peripheral leukocyte metabolism. Specifically, plasma metabolites and enzyme activities were assessed. In addition, quantitative RT-PCR was used to determine changes in insulin signaling gene (insulin receptor substrate (IRS)-1, IRS-2 and phosphatidylinositol 3-kinase (PI3-K) P85α) mRNA levels in peripheral leukocytes. Lastly, leukocyte enzymes involved in cellular energy metabolism were examined for changes in glucose utilization. Our results indicated that intensive insulin treatment was successful in type 1 DM dogs, leading to tight glycemic control. The mean glucose concentration and glycated albumin percentage significantly decreased to 156 mg/dl and 15.6%, respectively, following treatment. In peripheral leukocytes, the IRS-2 and PI3-K p85α mRNA levels significantly increased, and a significant increase in pyruvate kinase and pyruvate carboxylase activity, two enzymes involved in cellular energy metabolism, was also observed post treatment. Therefore, the observed changes in insulin signaling pathway activity and cellular energy metabolism enzyme activity in peripheral leukocytes are considered to be characteristics of amelioration of glucose metabolism by insulin action. As such, peripheral leukocytes are sufficiently sensitive to monitor for improving glycemic control during intensive insulin treatment of type 1 DM dogs. Blood cells such as leukocytes are much more readily available than muscle or adipose tissue for studies in dogs.
A three-year-old, 7.3-kg, female Pembroke Welsh Corgi exhibited symptomatic tongue atrophy, crinkling of the tip of the tongue, dysphagia and excessive salivation. Neurological examination suggested multiple cranial neuropathy, but polymyositis was diagnosed by magnetic resonance imaging and muscle biopsy. The dog did not respond to prednisolone treatment and died from aspiration pneumonia 22 months after the first presentation. Post-mortem histopathological examination of the tongue revealed marked myofiber loss and fibrosis with multifocal infiltration of mixed mononuclear cells. Similar findings were also observed in the masticatory muscles and quadriceps without abnormality of peripheral nerves or evidence of infection. Symptomatic tongue atrophy occurring in the course of polymyositis has not been reported previously in dogs.
Four pasture-fed Japanese Black cows showed the main clinical symptoms of severe hemoglobinuria at different periods between 2003 and 2007. Hematological analyses at the first consultation revealed severe anemia, and biochemical analyses indicated both severe hemolysis and disruption of hepatic function. Although the first 2 patients died, the hemoglobinuria and general condition of the remaining 2 cows, who were immediately initiated on large doses of antibiotics, improved within 3 days. Clostridium haemolyticum was detected by polymerase chain reaction (PCR) analysis of the blood sample of 1 of the infected cows. Anti-fascioliasis medicine is administered, and since then, no case of hemoglobinuria has been observed. The cows were diagnosed with bacillary hemoglobinuria, and they represent the first few cases in Japan.
Older cows show a high incidence of infectious diseases during the periparturient period. The periparturient infectious diseases are closely associated with the immune function of dairy cows during the pre-calving period. In order to evaluate the relationship between the immune cell population and age in the cows during the pre-calving period, we obtained blood samples from 170 dairy cows during the pre-calving period. We chose only healthy cows, which did not develop clinical diseases within 2 weeks after the calving in this study. The animals were divided into 4 groups based on their parity: in their 1st pregnancy (Group 1), in their 2nd pregnancy (Group 2), in their 3rd calving (Group 3) and in more than 3rd pregnancy (Group 4). The numbers of the peripheral blood CD3+TcR1-N12+ and MHC class-II+CD14- lymphocytes were significantly higher in Group 1 compared to Group 4. This result indicated that the lower γδT cells and B cells in older cows compared with heifer during pre-calving period.
Inhibition and prevention of mosquito bloodsucking by a topical insecticide, and the consequent infection of Dirofilaria immitis were evaluated using a product containing 10% w/w imidacloprid plus 50% w/w permethrin (I-P solution). Nine healthy beagle dogs divided in three groups of 3 dogs each were administered I-P solution on day 3 (group 1), day 36 (group 2) and not administered (group 3 as a control) before starting the experimental infection. The results showed that the mosquito bloodsucking rate was significantly lower, 12.1% in group 1 (p<0.05) and 11.1% in group 2 (p<0.05), than the 40.6% in group 3, meaning that the inhibition rates in groups 1 and 2 against group 3 were 70.2% and 72.7%. The infection rate of experimental D. immitis infection was 33% in group 1, 33% in group 2 and 100% in group 3, meaning that the prevention rates in groups 1 and 2 against group 3 were 67% and 67%.
A coprological survey was performed at a slaughterhouse in Osaka, Japan, from 2004 to 2007 on 129 pigs reared in 8 prefectures, and on 213 cattle reared in 21 prefectures. Eimeria spp., Trichuris suis, Ascaris suum and Metastrongylus spp. infections were found in 52 (40.3%), 32 (24.8%), 19 (14.7%) and 3 pigs (2.3%), respectively, while Eimeria spp., Capillaria bovis and Trichuris sp. infections were detected in 163 (76.5%), 15 (7.0%) and 8 cattle (3.8%), respectively. Our results suggest that environmentally resistant oocysts and eggs of parasites could be widespread at the farms examined.
Zinc deficiency induces a wide range of disorders including immunodeficiency. It is known that microbial infections occur with a high frequency in the zinc-deficient hosts, but the study on the correlation between parasitic infection and zinc status in hosts is scarcely performed. We observed that the influence of zinc deficiency to the rats infected with Babesia rodhaini. Experiments of B. rodhaini infection were conducted using zinc-deficient (ZD; eat ad libitum or 10 g/day on the ZD diet), zinc-adequate (ZA; eat ad libitum on the ZA diet), and diet-restricted (DR; eat 7 g/day on the ZA diet) rats. The findings in this study suggested that the zinc deficiency had deleterious effects on the hemodynamics and mortality of the rats infected with B. rodhaini.
Babesia gibsoni (B. gibsoni) is a tick-borne hemoprotozoan parasite, which causes piroplasmosis in dogs. Diagnosis of canine babesiosis is commonly carried out using Giemsa-stained thin blood smears. However, at low levels of infection, it is difficult to detect Babesia organisms by observation of Giemsa-stained thin blood smears. We constructed a monoclonal phage display single chain antibody (scFv) against a B. gibsoni merozoite antigen, P50 protein. Intraerythrocytic B. gibsoni organisms are clearly stained using this antibody. The monoclonal scFv facilitated the detection of B. gibsoni organisms in canine blood samples.
A total of 14,818 slaughtered pigs were examined macroscopically. Of these, 25 pigs with porcine pleuropneumonia were collected and the relations among Actinobacillus spp. and granulomatous lesions in organs (lungs and tonsils) were evaluated. In the lungs, only Actinobacillus pleuropneumoniae serotype 2 was isolated from 20 of the pigs. Histologically, granulomatous pneumonia with A. pleuropneumoniae antigen was detected in 8 of the pigs. The antigen was visible in the centers of the lesions along with asteroid bodies, epithelioid cells and multinucleated giant cells. In the tonsils, granulomatous lesions were not detected, although A. pleuropneumoniae serotype 2 (5 pigs), serotype 7 (1 pig), Actinobacillus porcitonsillarum (1 pig) and Actinobacillus minor (1 pig) were isolated. The present survey suggests that multifocal granulomatous pneumonia in slaughter pigs could be highly associated with A. pleuropneumoniae serotype 2 infection.
A 17-year-old spayed female Japanese domestic cat presented with a solitary cutaneous mass in the right thoracic area. Histopathologically, the mass consisted mainly of round tumor cells that had infiltrated throughout the dermis and deep subcutaneous tissue. The proliferating pattern of tumor cells was solid but also trabecular or cord-like in some areas, and lined with small cells resembling mature lymphocytes or basal cells. The tumor cells were positive for cytokeratin 20 and synaptophysin. The positive reaction for cytokeratin 20 showed localized to diffuse pattern. This is the first report describing now cytokeratin 20 was clearly beneficial for the differential diagnosis of feline Merkel cell carcinoma.
A mass lesion in the medulla oblongata in a 9-year-old female Golden Retriever was examined pathologically. The medullary mass was 1 to 2 cm in diameter and poorly demarcated. The cut surface was discolored with numerous sand-like materials. Histologically, the mass lesion consisted of complex proliferation of irregularly arranged vessels as well as astrocytes with numerous mineral deposits. The astrocytic components exhibited no apparent anaplastic morphology. The proliferating vessels were either veins with muscle layer and capillaries. A few axons and myelinated fibers were also found in the lesion. The number of ki-67-positive cell nuclei was extremely small, suggesting the poor growth activity of these cells. Based on the findings, the lesion was considered to be a non-neoplastic, hamartomatous change.
A case of intranuclear coccidiosis in an 11-month-old female Japanese Black calf is described. Because the calf exhibited diarrhea and failure to grow and then became moribund, euthanasia was performed. Histologically, the small intestinal villi were highly atrophic, and the epithelial cells frequently had meronts or merozoites within the nuclei. A few intranuclear gametocytes were also seen. The presence of Eimeria alabamensis-specific DNA in the lesions was demonstrated by polymerase chain reaction and nucleotide sequence analyses. Electron microscopy disclosed that most parasites were within nuclear inclusions encircled by the two membranes derived from the nuclear envelope, and that intracytoplasmic meronts and merozoites were in direct contact with the cytosol. Apparently, mature merozoites could be free without destruction of the host cells, and this may be associated with the relatively low pathogenicity of this coccidium.
This report describes the morphological and immunohistochemical findings of a case of apparent collagenofibrotic glomerulonephropathy in a 7-month-old dog. Clinical examination showed moderate protenuria with elevated blood urea nitrogen and creatinine. Histopathological examination of the glomerular capillary walls and mesangial areas revealed diffuse and global accumulation of eosinophilic homogeneous or fine fibrous materials, which were immunohistochemically positive for type III collagen. On electron microscopy, the randomly crossed fibrils had transverse bands with a periodicity of approximately 60 nm. The clinical, histopathological, immunohistochemical and electron microscopic findings of the present dog were consistent with those of the human, childhood form of collagenofibrotic glomerulonephropathy.
Isobutyl-paraben (IBP), a widely used preservative in a variety of foods, shows high comparative binding affinity to estrogen receptors. Here, we examined the effects of maternal exposure of rats to IBP on plasma hormone concentrations and organ weights in dams, ratio of male pups, anogenital distance, organ weights and plasma hormone concentrations in offspring, puberty, estrous cycle and response of organ weight and plasma hormone concentrations to estrogen in adult female offspring, and reproductive and adrenal function in adult male offspring, all of which are under developmental estrogen regulation, to clarify the estrogenic effects of IBP during gestation and lactation on the endocrine systems of dams and offspring. While maternal exposure of IBP decreased the plasma corticosterone concentration and increased the uterus weight in dams and increased uterine sensitivity to estrogen in adult female offspring, the other indices examined were largely unaffected by the present treatment. Even though these results indicate little sign of endocrine disrupting effects for IBP, the existence of activity may be a matter of concern due to the possible impact on the health of future generations.
To clarify the involvement of apoptosis in the immunotoxicity of organotin compounds, we examined the induction of apoptosis in the peripheral lymphocytes and thymus of mice treated with triphenyltin (TPT), tributyltin (TBT) or dexamethasone (Dex). Application of TPT or TBT and Dex resulted in a transient reduction in peripheral lymphocytes at 3 to 6 hr, and thymus atrophy was observed at 6 and 24 hr after administration. Lymphocyte subpopulation analysis showed that TPT and TBT induced a greater reduction in B cells than in T cells. The maximum levels of organotin in the blood were about 450 ng TPT/ml in the TPT-treated mice, and 170 ng TBT/ml in the TBT-treated mice. When the isolated peripheral lymphocytes were incubated with the organotins at 500 ng/ml, TPT and TBT induced necrosis in over 70% of cells, while both organotins caused lower percentages of apoptosis as well as necrosis after 3 hr at 100 ng/ml. In the thymus, although in vivo treatment of mice with Dex caused apoptosis, neither apoptotic nor necrotic thymocytes were observed in the TPT- and TBT-treated mice, indicating that the thymus atrophy might be caused by the antiproliferative effects of these organotin compounds. Thus, our results did not support the idea that apoptosis played a decisive part in the immunotoxicity of the organotin compounds in vivo.
This report describes the use of magnetic resonance imaging (MRI) to diagnose cervical syringomyelia in 4 cats. MRI revealed enlargement of the lateral ventricle in all the cats. Of the 4 cases, MRI revealed herniation of the cerebellum in 3 cats, an isolated fourth ventricle in 1 cat, severe hydrocephalus in 2 cats and brain masses in 1 cat. In this report, the cervical syringomyelia in these cats may have been due to formation of a secondary syrinx (enlargement of the central canal) as a result of blockage of flow in the outlet of the fourth ventricle caused by FIP encephalomyelitis or secondary cerebellar tonsillar herniation caused by increased intracranial pressure due to intracranial masses or may have been due to caudal compression of the cerebellum caused by increased intracranial pressure due to hydrocephalus.
To better understand the neurotoxicity caused by the pyrethroid pesticide, we examined the effects of the N-methyl-D-aspartate (NMDA) receptor antagonists MK-801, a non-competitive cation channel blocker, and 2-amino-5-phosphonovaleric acid (APV), a competitive Na+ channel blocker, on extracellular dopamine levels in male Sprague-Dawley rats receiving the type II pyrethroid deltamethrin using an in vivo microdialysis system. Deltamethrin (60 mg/kg, i.p.) evidently increased striatal dopamine levels with a peak time of 120 min, and the local infusion (i.c.) of either MK-801(650 μM) or APV (500 μM) completely blocked these actions. The fluctuation in the dopamine metabolite 3-MT also resembled that in dopamine. Our results suggest that dopamine-releasing neurons would be modulated via the NMDA receptor by the excitatory glutamatergic neurons after deltamethrin treatment.
We have examined the seroprevalence of BDV in wild Raccoons (Procyon lotor) in Hokkaido, Japan. Serum samples from raccoons were examined using ELISA and Western blot assays to detect the presence of serum antibodies that react specifically to BDV antigens. Among 549 investigated individuals, eleven (2.0%) showed a positive reaction to BDV antigens. Brain tissue samples from five individuals were subjected to RT-PCR, which detected BDV sequences in three of them. Sequence analysis revealed a high degree of genetic conservation between BDV sequences derived from raccoons and previously published sequences derived from other animal species.
Japanese encephalitis virus (JEV) infects numerous animal species including humans, horses and pigs. In this study, antibodies against JEV in feral raccoons (Procyon lotor), wild boars (Sus scrofa) and raccoon dogs (Nyctereutes procyonoides) in Japan were examined. The results showed that 40.7% (22 out of 54), 64.5% (40 out of 62), 69.1% (47 out of 68) and 0% (0 out of 20) of raccoons in Hyogo, Osaka, Wakayama and Hokkaido, respectively, had virus-neutralizing antibodies against JEV. In addition, 83.3% (30 out of 36) of wild boars and 63.2% (12 out of 19) of raccoon dogs in Wakayama were seropositive for JEV. There were no significant differences in seroprevalence of JEV between males and females or between adults and juveniles in these wild animals. JEV seroprevalence was compared between 37 raccoons and 30 wild boars captured in a limited period (November 2007 to February 2008), and we found that wild boars (86.7%) were significantly more seropositive for JEV antibody than raccoons (59.5%). In conclusion, JEV was prevalent in wild mammals, indicating that the possibility of JEV infection in humans may still be high in Japan. In addition, these wild animals may be good sentinels to estimate JEV infection risk in residents, as they live near humans and are not vaccinated.
A total of 90 blood samples were collected from wild boars in the Kyushu region of Japan, and a seroepidemiological survey for 7 arthropod-borne viruses was performed using hemagglutination inhibition tests. The individual seropositive rates for each virus were 52.2% for Japanese encephalitis virus (JEV), 47.8% for Getah virus (GETV), 13.3% for Akabane virus, 10.0% for Aino virus and less than 5% for Bluetongue virus, Chuzan virus and Ibaraki virus. The results indicated that among the 7 viruses, JEV and GETV infections were prevalent among the wild boars and that the animals were involved in the natural transmission cycle of JEV and GETV in Japan. It is necessary to consider the participation of wild animals for the control of arthropod-borne virus infections.