Distribution of inclusion bodies in tissues from 100 dogs infected with canine distemper virus

One hundred dogs that were positive for canine distemper virus antigen and inclusion bodies in the tonsils were examined for the distribution of inclusion bodies in various tissues. Inclusion bodies were found in the lungs (70 dogs), brains (20 dogs), urinary bladders (73 dogs), stomachs (78 dogs), spleens (77 dogs), and lymph nodes (81 dogs) of the dogs. Based on these results, the tonsils may be the most suitable tissue for detection of inclusion bodies in canine distemper.     

Induction of apoptotic lesions in liver and lymphoid tissues and modulation of cytokine mRNA expression by acute exposure to deoxynivalenol in piglets

Six 1-month-old piglets were intravenously injected with deoxynivalenol (DON) at the concentration of 1 mg/kg body weight, with three pigs each necropsied at 6 and 24 h post-injection (PI) for investigation of hepatotoxicity and immunotoxicity with special attention to apoptotic changes and cytokine mRNA expression. Histopathological examination of the DON-injected pigs revealed systemic apoptosis of lymphocytes in lymphoid tissues and hepatocytes. Apoptosis of lymphocytes and hepatocytes was confirmed by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method and immunohistochemical staining against single-stranded DNA and cleaved caspase-3. The number of TUNEL-positive cells in the thymus and Peyer''s patches of the ileum was increased at 24 h PI compared to 6 h PI, but the peak was at 6 h PI in the liver. The mRNA expression of interleukin (IL)-1β, IL-6, IL-18, and tumor necrosis factor (TNF)-α in the spleen, thymus and mesenteric lymph nodes were determined by semi-quantitative RT-PCR, and elevated expression of IL-1β mRNA at 6 h PI and a decrease of IL-18 mRNA at 24 h PI were observed in the spleen. IL-1β and IL-6 mRNA expressions increased significantly at 6 h PI in the thymus, but TNF-α decreased at 6 h PI in the mesenteric lymph nodes. These results show the apoptosis of hepatocytes suggesting the hepatotoxic potential of DON, in addition to an immunotoxic effect on the modulation of proinflammatory cytokine genes in lymphoid organs with extensive apoptosis of lymphocytes induced by acute exposure to DON in pigs.     

Effects of apple pomace‐mixed silage on growth performance and meat quality in finishing pigs

We measured the growth performance and meat quality of 10 crossbred (Yorkshire × Duroc × Landrace) neutered male pigs to evaluate the effects of apple pomace‐mixed silage (APMS). The pigs were divided into two groups and were respectively fed the control feed and the AMPS ad libitum during the experiment. No difference was found in the finished body weight, average daily gain, carcass weight, back fat thickness or dressing ratio between the control and the AMPS treatments, but average dairy feed intake (dry matter) was significantly lower and feed efficiency was significantly higher using the APMS treatment (P < 0.05). With regard to meat quality, the APMS increased the moisture content but decreased the water holding capacity (P < 0.05) compared with the control treatment. Furthermore, the APMS affected the fatty acid composition of the back fat by increasing linoleic acid (C18:2n6), linolenic acid (C18:3) and arachidic acid (C20:0) levels, while decreasing palmitic acid (C16:0), palmitoleic acid (C16:1) and heptadecenoic acid (C17:1) levels, compared with the control treatment. These results indicate that feeding fermented apple pomace to finishing pigs increases the feed efficiency and affects the meat quality and fatty acid composition of back fat.     

Recognition pattern of thyroglobulin autoantibody from hypothyroid dogs to tryptic peptides of canine thyroglobulin

Circulating thyroglobulin autoantibody (TgAA) was analyzed using the Western immunoblot for determination of the dominant epitopes recognized by TgAA on tryptic peptides of canine thyroglobulin (cTg) in hypothyroid dogs. TgAA was measured in hypothyroid dogs, non-hypothyroid dogs with skin diseases and clinically normal dogs. Five of the 7 hypothyroid dogs, 1 of the 8 dogs with skin diseases and 1 of the 4 normal dogs were positive for TgAA. Four of the 5 TgAA-positive hypothyroid dogs were Golden Retrievers, and 3 of them showed high antibody titers. The sera of TgAA positive-dogs reacted to several peptides, and their patterns varied from sample to sample. Sera from 3 dogs with high titers of TgAA reacted broadly to high molecular weight peptides ranging from 45 to 90 kDa. These Western immunoblot patterns of the sera were disappeared after pretreatment with sufficient amount of intact cTg. All serum samples of both TgAA positive dogs and negative controls reacted to low molecular weight peptides ranging from 15 to 20 kDa. These immunoblot patterns of the sera were not disappeared even after pretreatment with sufficient amount of intact cTg. These findings show the possibility that the epitopes recognized by TgAA depend upon individual dogs with hypothyroidism and these autoantibodies recognize conformational epitopes on the cTg molecule.     

Relation between phenotype of tumor cells and clinicopathology in bovine leukosis

Thirty-three cases of enzootic bovine leukosis (EBL) and 14 cases of sporadic bovine leukosis (SBL) were examined by immunohistochemistry using 6 monoclonal antibodies against leukocyte differentiation molecules of bovine leukocytes. There were 17 cases of B-1a cell type, 10 cases of B-1b cell type and 6 cases of B-2 cell type in EBL, and 5 cases originating from B cells (B-2 cell type) and 9 cases originating from immature T cells in SBL. The average age for the EBL cases of B-1a cell type was 8.6 years, B-1b cell type was 6.5 years, and of B-2 cell type was 4.5 years. In cases of SBL, immature T cell type patients were younger than B-2 cell type ones. The lymphoma originating from B cells differed from that originating from T cells in morphology. In T cell tumors, the nucleus of tumor cells was round, the edge of the cytoplasm obvious, and tumor cells were sporadically present and proliferated. When compared with T cells, the region among B cells was obscure. But, there was no relation between phenotype and the histologic classification of tumor cells. In EBL, beyond the lymph node, tumors of B-1a and B-1b types had developed in the heart and abomasum, and those of the B-2 type tended to occur in liver. In SBL, B-2 type and T type cells formed tumors in the liver, kidney, thymus, and one case of T-cell type tumor formed on the skin. We would like to propose a new classification of bovine leukosis as EBL, calf type B-cell lymphoma, juvenile T-cell lymphoma and skin type T-cell lymphoma.     

Fat depot‐specific differences in leptin mRNA expression and its relation to adipocyte size in steers

ABSTRACT This experiment was conducted to investigate leptin mRNA expression, adipocyte size, and their relationship in several adipose tissues of fattening steers. Subcutaneous, perirenal, intermuscular and intramuscular adipose tissues were collected from three crossbred steers (Japanese Black cattle X Holstein) aged 21 months. The mRNA level and adipocyte diameter were determined in these adipose tissues. The intramuscular adipose tissue had a lower leptin mRNA level than the intermuscular and perirenal adipose tissues (P < 0.05). Leptin mRNA level was lower in the subcutaneous depot than in the intermuscular depot (P < 0.05). Adipocyte diameter was larger in the intermuscular adipose tissue than in the subcutaneous and intramuscular adipose tissues (P < 0.05). Leptin mRNA level was positively correlated with adipocyte diameter (r² = 0.81, P < 0.05). These results suggest that the cattle have fat depot‐specific differences in leptin gene expression, which are a result of a difference in adipocyte size.     

Cytologically atypical anal sac adenocarcinoma in a dog

A 10-year-old intact female Shetland Sheepdog with tenesmus had a subcutaneous mass at the left ventral aspect of the anus. On cytologic examination, 2 types of cells were observed. Most of the cells were oval to polygonal and had elliptical or elongate nuclei and a moderate amount of pale to basophilic cytoplasm. The remaining cells had round to oval nuclei and pale to basophilic cytoplasm. Cells of both types were loosely adhered to each other and were arranged in rosette-like structures. Both neoplastic cell types had fine homogenous chromatin and either a small indistinct nucleolus or no visible nucleolus. Mild anisokaryosis and anisocytosis were observed. Histologically, the mass consists of glandular structures formed by cuboidal cells admixed with bundles of spindle cells. Eosinophilic PAS- and Alcian blue-positive secretory material was found in the center of some glandular structures. Both neoplastic cell types had positive staining with paradoxical concanavalin A and expressed cytokeratin, but not vimentin, S-100, α-smooth muscle actin, or desmin. Based on location and histologic and immunohistochemical features, the final diagnosis was adenocarcinoma of the apocrine gland of the anal sac, which should be included as a cytologic differential diagnosis when spindle cells and typical epithelial cells are observed in masses in the region of the anal sac of dogs.     

Effects of apple pomace proportion levels on the fermentation quality of total mixed ration silage and its digestibility,preference and ruminal fermentation in beef cows

Four Japanese black beef cows were used in a 4 × 4 Latin square to evaluate the fermentation quality, digestibility, ruminal fermentation and preference of total mixed ration (TMR) silages prepared with differing proportions of apple pomace (AP). Experimental treatments were the control (no AP added, CAP), 5% (low, LAP), 10% (medium, MAP) and 20% (high, HAP) of TMR dry matter (DM) as AP. All TMR silages were well preserved. Ethanol was produced in silages containing AP and the amount increased with the proportion of AP (P < 0.05). Nutrient digestibility with LAP, MAP and HAP treatment was lower than that with CAP treatment (P < 0.05). The ruminal molar proportion of acetic acid increased (P < 0.05), but the ruminal ammonia‐N concentration decreased (P < 0.05) as the proportion of AP increased. The preference of the animals was highest for HAP, followed by MAP, CAP and LAP. This study demonstrates that decrease in nutrient digestibility might be related to the ethanol produced naturally from AP. Therefore, the proportion of AP in TMR silages should be less than 5% of dietary DM.     

Histopathological characteristics of Ito cells and Kupffer cells in the feline liver

The histopathological characteristics of Ito cells and Kupffer cells were investigated in the liver of 21 cats (age range: 6 months -18 years) autopsied in our laboratory during 2003. Immunohistochemical examinations were performed using antibodies against lysozyme, desmin and alpha-smooth muscle actin. No Kupffer cells reacted with the antibody against lysozyme. However, macrophages in the lung and spleen showed a positive reaction with the antibody. This finding suggests a possibility that the amount of lysozyme in the Kupffer cells of feline liver is comparatively small. On the other hand, large vacuole-laden cells were observed in the hepatic perisinusoid of some feline cases, and these cells showed a positive reaction with antibodies against desmin and alpha-smooth muscle actin. These cells could be Ito cells with large lipid vacuoles. This conclusion was supported by electron microscopic observation and oil red O staining. However, no such large vacuole-laden perisinusoidal cells were detected in the liver of young cats less than 2 years old. The present study revealed the histopathological features of Kupffer cells and Ito cells in the feline liver.     

Comparison of cell populations derived from canine olfactory bulb and olfactory mucosal cultures

OBJECTIVE: To evaluate the numbers and proportions of olfactory ensheathing cells (OECs) in cell cultures derived from the olfactory bulb (OB) and olfactory mucosa of dogs. ANIMALS: 7 dogs. PROCEDURES: OB tissue and olfactory mucosa from the nasal cavity and frontal sinus were obtained from euthanatized dogs and prepared for cell culture. At 7, 14, and 21 days of culture in vitro, numbers and proportions of OECs, astrocytes, and fibroblasts were determined via immunocytochemistry. Antibody against the low-affinity nerve growth factor receptor p75 was used to identify OECs, antibody against glial fibrillary acidic protein was used to identify astrocytes, and antibody against fibronectin was used to identify fibroblasts. RESULTS: Cultured OECs derived from the olfactory mucosa of the nasal cavity and frontal sinus had similar characteristics. However, whereas OECs in the OB cell cultures constituted approximately 50% of the cells at 7 days and approximately 75% at 21 days the proportion of OECs in cultures derived from both mucosal types was much lower, with approximately 40% OECs at 7 days and approximately 25% at 21 days. Analysis of OEC numbers revealed that these changes were accompanied by corresponding decreases and increases in the population of cells with fibronectin receptors. CONCLUSIONS AND CLINICAL RELEVANCE: Although olfactory mucosal cell cultures yielded a sufficient number of OECs for spinal cord transplantation procedures in dogs, modification of culture conditions would be required to ensure that the derived cell population contained a sufficient proportion of OECs.