Mast cell tumor in the nasal cavity of a dog

An 11-year-old male Shetland sheepdog displayed epistaxis and nasal discharge from the left nasal foramen. Cytological examination of a smear sample obtained by rhinotomy revealed neoplastic mast cells in the nasal cavity, a definitive diagnostic sign of mast cell tumor. The case was treated by surgery combined with radiotherapy and chemotherapy. Eighteen days after the last treatment, marked enlargement of the mandibular lymph nodes and facial edema developed, and the dog was euthanized at the owner's request. At necropsy, metastatic proliferation of mast cells was confirmed in the lymph nodes and liver, but no neoplastic mast cells were observed in the nasal cavity.     

Evaluation of plasma erythropoietin levels in normal adult dogs by in vivo bioassay using concentrated plasma.

Measurement of plasma erythropoietin level in normal dogs by in vivo bioassay has been considered to be impossible so far. In the present study, we successfully determined it by using concentrated plasma 60 times which allowed the lower limit to 2.7 mU/ml. This normal plasma erythropoietin level was the first to be determined as an in vivo bioactivity and was 9.14 +/- 7.81 mU/ml in 75 normal adult dogs. This value was sufficiently reliable in terms of accuracy of determination and considered to be meaningful as the low level in vivo bioactivity that hasn't been known to date. Furthermore, erythropoietin levels in normal plasma were within a certain lower range and showed neither difference in plasma erythropoietin level between males and females or among breeds nor correlation between erythropoietin and hemoglobin level.     

Tumor necrosis factor alpha and its receptors in experimentally bovine leukemia virus-infected sheep

To examine whether tumor necrosis factor alpha (TNF alpha) contributes to the pathogenesis of bovine leukemia virus (BLV) infection, the mRNA expression patterns of TNF alpha and its receptors, type 1 (TNF R1) and type 2 (TNF R2) were investigated. Sheep inoculated with BLV were divided into two groups; one was BLV-positive and the other BLV-negative based on the detection in peripheral blood mononuclear cells (PBMC). Expression of TNF R1 mRNA was down-regulated in PBMC from the BLV-positive compared to BLV-negative sheep. No difference was shown in the expression levels of TNF R2 mRNA between the two groups. Furthermore, proliferative responses of PBMC in the presence of TNF alpha were observed from the BLV-positive, but not BLV-negative sheep. Membrane-bound TNF alpha (mTNF alpha) is thought to be one of the ligands, inducing B-cell activation. Flow cytometric analysis demonstrated that the number of PBMC, that were positive for mTNF alpha expression, was increased in the BLV-positive sheep. Thus, the expression of TNF alpha and its receptors may be closely associated with lymphocytosis induced by BLV.     

Host immune responses in the course of bovine leukemia virus infection

Bovine leukemia virus (BLV) is a type C retrovirus infecting bovine B cells and causing enzootic bovine leukosis. Since it takes long periods to develop the disease, it is believed that BLV and host immune responses are closely related. In this review, the accumulated data showing close relationship between BLV and host immune responses are summarized in 4 sections. First, we discuss the role of cell-mediated immunity in protecting hosts from BLV infection. Second, several reports showing the relationship between the disease progression and the change of cytokine profiles are summarized. In the third section, we have focused on tumor necrosis factor alpha (TNFalpha) and its two types of receptors, and the possible involvement of TNFalpha in the BLV-induced leukemogenesis is discussed. The expression of TNFalpha has been shown to be regulated by major histocompatibility complex (MHC) haplotype. The resistance to BLV infection is supposed to be established by some innate factors, which are closely related to MHC haplotype. Finally, we propose that a breeding strategy based on the MHC haplotype could be a good approach to control BLV infection. This review includes some recent data from us and other groups.     

Role of beta1 integrins in adhesion of canine mastocytoma cells to extracellular matrix proteins

The interactions of tumor cells with the extracellular matrix (ECM) are a crucial step in invasion and metastasis. Integrins are adhesive molecules forming heterodimers with alpha and beta subunits that play a definitive role in these interactions. In this study, mastocytoma (mast cell tumor: MCT) cell-ECM interaction was investigated using 3 canine MCT cell lines: CM-MC (originating from cutaneous MCT), VI-MC (originating from intestinal MCT), and CoMS (originating from oral MCT). Flow cytometric analysis showed that all cells highly expressed the integrin beta1 and alpha1 through alpha5 subunits and that they moderately expressed the alpha6 subunit. In adhesion studies, CoMS weakly but spontaneously adhered to fibronectin (FN), which was enhanced by phorbol ester (TPA), while CM-MC and VI-MC required cell activation by TPA to adhere to FN. Anti-beta1 and alpha5 integrin antibodies strongly inhibited cell adhesion to FN in CM-MC and CoMS and moderately inhibited cell adhesion in VI-MC. Only VI-MC adhered to laminin (LN) under activation by TPA. Anti-beta1 integrin antibodies strongly inhibited cell adhesion to LN, but all anti-alpha integrin antibodies failed to inhibit cell adhesion to LN. No cells adhered to collagen types I and IV. Canine MCT cells from different origins expressed similar integrin patterns; however, there were some differences in adhesive behavior in response to various ECM proteins and activating stimuli.     

Isolation of a viable but non-culturable suppression mutant of Vibrio vulnificus: role of antioxidant enzymes in surviving stationary phase and low temperatures

ABSTRACT:   The viable but non-culturable (VBNC) suppression mutant was isolated. Suppression subtractive hybridization was used to identify differentially expressed genes among cDNA of the VBNC suppression mutant and the wild-type strain. RpoS-dependent catalase was highly expressed from the VBNC suppression mutant during oxidative stress in the stationary phase and at low temperatures. In experiments of H₂O₂ sensitivity, the VBNC suppression mutant showed a peroxide-resistant phenotype in the stationary phase and at low temperatures. These results suggest that VBNC suppression mutant cells use catalase for protection against oxidative stress in the stationary phase and at low temperatures.     

Late onset cerebellar cortical degeneration in a koala

A 10-year-old male koala started to fall from the tree while sleeping. Subsequently, the koala often fell down while walking and showed a gait abnormality, abnormal nystagmus and hypersalivation. At 12 years of age, the koala became ataxic and seemed blind. At 13 years of age, the koala exhibited signs of dysstasia and was euthanased. Necropsy revealed marked symmetrical atrophy of the cerebellum. Histopathologically, a severe loss of Purkinje and granule cells was evident in the cerebellum, while the molecular layer was more cellular than normal with cells resembling small neurons, which were positively stained with parvalbumin immunohistochemistry. Reactive Bergmann glial cells (astrocytes) were present adjacent to the depleted Purkinje cell zone. The very late onset and slow progression of the cerebellar cortical degeneration in this case is particularly interesting and appears to be the first report in the koala.     

Quantification of water buffalo (Bubalus bubalis) cytokine expression in response to inactivated foot-and-mouth disease (FMD) vaccine

This study describes the quantification of cytokine expression of vaccinated water buffaloes with FMD inactivated vaccine. Using real-time PCR quantification assay, expression of Th1 (IL-2, IL-12p40, IFNγ); Th2 (IL-4, IL-10) and inflammatory (IL-6, TNFα) cytokines were quantified weekly for the entire three-week duration of the experiment. It was noted that IFNγ, IL-10 and TNFα had peaked on week three post-vaccination while the remaining cytokines peaked on the second week and decreased by the third week. The counteraction between IFNγ and IL-4 was noted as well as the possible suppressive action of IL-10 to that of IL-2 and IL-12, which is a common phenomenon between Th1 and Th2 cytokines. Synergy between TNFa and IL-6 was also observed. These findings suggest that within the immune system of water buffalo there is a dynamic cell-mediated and humoral interaction in response to immunogen. This assessment of the cytokine expressions is vital for the study of water buffalo disease progression and concurring protective immune responses.