Colonic mast cell infiltration in rats with TNBS-induced visceral hypersensitivity

Colonic mucosal mast cells are implicated in the pathogenesis of visceral hypersensitivity associated with irritable bowel syndromes. This study was designed to investigate the roles of mucosal mast cells in development of an experimental visceral hypersensitivity induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in rats. TNBS, when injected into the proximal colon through laparotomy, produced a significant decrease in pain threshold of the distal colon to mechanical distention, indicating a visceral hypersensitivity. In the proximal colon that was directly insulted by TNBS, mucosal necrosis and extensive inflammatory cell infiltration were observed with concomitant increase in tissue myeloperoxide (MPO) activity. In the distal colon where distention stimuli were applied, the number of mucosal mast cells significantly increased following TNBS treatment, although neither mucosal injury nor increase in tissue MPO activity was observed. In an organ culture, spontaneous release of a mucosal mast cell-specific protease (RMCP-2) from the distal colon tissue of TNBS-treated rats was significantly larger than that of sham animals. Furthermore, TNBS-induced visceral hypersensitivity was significantly suppressed by subcutaneous pretreatment with a mast cell stabilizer doxantrazole in a dose-dependent manner. These findings suggest that prominent colonic mast cell infiltration associated with an enhanced spontaneous mediator release is responsible, at least partly, for development of visceral hypersensitivity induced by TNBS in rats.     

Immunohistochemical detection of apolipoprotein B-100 and immunoglobulins (IgA, IgM, IgG) in the splenic arteries of aging dogs

Accumulation of lipids and hyalinosis in the splenic arteries of aged dogs are frequently detected by routine histopathologic examinations. The purpose of this study was to pinpoint the localization of canine apolipoprotein B-100 (CApoB-100) and immunoglobulins (IgA, IgM, IgG) in the splenic arteries of aging dogs (n = 80) through the use of immunohistochemical techniques. CApoB-100 deposits were found in the subendothelial space, extracellular matrix, and atheromatous lesions in the tunica media of the arteries in dogs > or = 6 years of age. Foamy cytoplasm of the infiltrated macrophages was also CApoB-100 immunopositive. In dogs > or = 10 years of age, almost all central arteries were CApoB-100 immunopositive. Hyaline deposits within the wall were characterized by immunopositivity against canine IgA, IgM, IgG, and albumin. Lipid accumulation in splenic arteries may be an age-related lesion and a precursor of the atheromatous plaques associated with splenic hemorrhage and infarcts later in life. In addition, deposition of immunoglobulins, probably mediated by immune complexes, may play an important role in the development of canine vascular diseases similar to human disease.     

Immunohistochemical evaluation of a malignant phecochromocytoma in a wolfdog

A malignant pheochromocytoma with multiple metastases was diagnosed in a 7-year-old male wolfdog that resulted from a cross between an eastern timber wolf (Canis lupus lycaon) and an Alaskan malamute. A yellowish white neoplastic mass approximately 10 cm diameter was found in the right adrenal gland. The neoplasm penetrated through the wall of the caudal vena cava. A diagnosis of pheochromocytoma was established by histopathologic and immunohistochemical procedures. Immunohistochemically, the neoplastic cells expressed chromogranin A, substance P, synaptophysin, Leu-7, protein gene product 9.5, methionine-enkephalin, S100 protein, and galanin. Multiple metastatic tumors were found in the kidneys, spleen, lungs, heart, and liver.     

Establishment of a potency test by ELISA for a rabies vaccine for animal use in Japan

The ELISA we developed was able to determine the antigen content and was suitable for a potency test, and we described a relative potency assay method which determines the potency of test vaccines by comparing the ELISA value of a test vaccine to that of a reference vaccine. In the present study, we standardized the reference vaccine used for determining the potencies of test vaccines, and established a potency test by ELISA. We evaluated the proposed reference vaccine by the neutralizing antibody responses in dogs after vaccination, by the challenge protection test in guinea pigs (GP potency test), which is the earlier official potency test used in Japan, and by the NIH potency test, which is widely used throughout the world. The results showed that a 4-fold dilution of the proposed reference vaccine induced sufficient immunity in dogs. A 3-fold dilution of the proposed reference vaccine passed the GP potency test. The international units (IU) calibrated by the NIH potency test were 3.7 IU/dose. From the results and the WHO recommendation that veterinary rabies vaccines should have a potency of at least 1.0 IU/dose, we determined to dilute the proposed reference vaccine by 3 fold and regarded it as the reference vaccine. Finally, we confirmed that there is a good agreement between the results of the potency test by ELISA and the results of the GP potency test. The establishment of the potency test by ELISA has made it possible to monitor the potency in the production process and has contributed to the stable production of the vaccine.     

Synthesis and insecticidal activity of benzoheterocyclic analogues of N'-benzoyl-N-(tert-butyl)benzohydrazide: Part 3. Modification of N-tert-butylhydrazine moiety

Nineteen analogues were synthesized by modifying the tert-butylhydrazine moieties of N'-tert-butyl-N'-(3,5-dimethylbenzoyl)-5-methyl-2,3-dihydro-1,4-benzodioxine-6-carbohydrazide and N'-tert-butyl-N'-(3,5-dimethylbenzoyl)-5-methylchromane-6-carbohydrazide (chromafenozide), and the synthesized analogues were evaluated for their insecticidal activity against Spodoptera litura F. While all of the synthesized analogues had insecticidal activity inferior to those of the lead compounds, several of the analogues nonetheless showed high insecticidal activity. Chromafenozide has shown very high selectivity toward lepidopteran species.     

Evaluation of intestinal intramucosal pH,arterial and portal venous blood gas values,and intestinal blood flow during small intestinal ischemia and reperfusion in dogs

OBJECTIVES: To determine whether small intestinal ischemia and reperfusion affects intestinal intramucosal pH (pHi), arterial and portal venous blood gas values, and intestinal blood flow (IBF) and to investigate relationships between regional intestinal tissue oxygenation and systemic variables in dogs. ANIMALS: 15 healthy adult Beagles. PROCEDURE: Occlusion of superior mesenteric artery (SMA) for 0, 30, or 60 minutes, followed by reperfusion for 180 minutes, was performed; IBF, pHi, arterial and portal venous blood gas values, arterial pressure, and heart rate were measured at various time points; and intestinal mucosal injury was histologically graded. RESULTS: Occlusion of the SMA induced significant decreases in pHi and IBF. After the release of the occlusion, IBF returned rapidly to baseline values, but improvement in pHi was slow. Arterial and portal venous blood gas analyses were less sensitive than tonometric measurements of pHi, and there was no correlation between results of blood gas analyses and tonometric measurements. Histologic score for intestinal mucosal injury increased significantly, depending on duration of ischemia, and there was a correlation between tonometric results and the histologic score. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that it is difficult to accurately evaluate local oxygenation disorders by monitoring at the systemic level, whereas clinically pHi is the only reliable indicator of inadequate regional intestinal tissue oxygenation in dogs.     

Polymerase chain reaction-restriction fragment length polymorphism analysis of the SzP gene of Streptococcus zooepidemicus isolated from the respiratory tract of horses

OBJECTIVE: To develop polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis for molecular typing of strains of Streptococcus zooepidemicus and to use the new typing method to analyze a collection of isolates from the respiratory tract of Thoroughbreds. SAMPLE POPULATION: 10 strains of S zooepidemicus, 65 isolates from the respiratory tract of 9 yearlings following long distance transportation, and 89 isolates from tracheal aspirates of 20 foals with pneumonia. PROCEDURE: Phenotypic variations in the SzP protein were detected by western immunoblot analysis. Using PCR-RFLP analysis, genotypes were obtained with primer sets from the SzP gene, followed by restriction endonuclease digestion of the amplicons. RESULTS: Unique genotypic patterns were obtained with a primer set designed from both ends of the structural gene and the restriction endonuclease DdeI. Forty-five isolates from the lymphoid tissue within the pharyngeal recess (ie, pharyngeal tonsil) of yearlings included 10 SzP genotypes and SzP phenotypes. Isolates from the trachea of each yearling were of a single genotype that was also present among isolates from the pharyngeal tonsil of the same horses. Isolates from tracheal aspirates of foals belonged to 14 genotypes. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of the SzP gene by use of PCR-RFLP was effective for molecular typing of strains of S zooepidemicus in the study of respiratory tract disease in horses. Results of PCR-RFLP analysis indicate that a single strain of S zooepidemicus can migrate from the pharyngeal tonsil to the trachea at a high rate in horses undergoing long distance transportation.     

Secondary chronic respiratory acidosis in a dog following the cervical cord compression by an intradural glioma

An intradural tumor in the upper cervical region was found in a dog with quadriparesis and chronic respiratory acidosis. Surgical removal of the tumor in the atlas and intraoperative radiotherapy were attempted. The tumor was histologically diagnosed as a neural glioma. A preoperative acid-base disturbance was dramatically improved after surgery. The clinical changes appeared in this case suggest that compression of the spinal cord at this region may cause paralysis of the respiratory muscles and secondarily result in chronic respiratory acidosis following the respiratory insufficiency.     

A pleomorphic adenoma of the lacrimal gland in a dog

A 13-year-old female mongrel dog had a pleomorphic adenoma of the lacrimal gland in the right upper orbit. The tumor measured 3.8 x 3.0 x 3.3 cm, appeared white, round, and firm, and pressed the right globe and surrounding tissues. Histopathologically, the tumor had a thin connective tissue capsule and was composed of tubules with two cell types, some resembling luminal epithelial cells making up the tubular structures and the other of myoepithelial cells. Epithelial tubules were disposed in an adenomatous fashion and separated from each other by proliferating pleomorphic myoepithelial cells. Immunohistochemically, large numbers of the luminal epithelial cells revealed an immunopositive reaction against keratin/cytokeratin (AE1/AE3), and some epithelial cells reacted against cytokeratin 14. Spindle-shaped myoepithelial cells revealed an immunopositive reaction against cytokeratin 14, alpha-smooth muscle actin, and vimentin. A small number of myoepithelial cells reacted against desmin. S-100 protein immunopositivity was frequently found in luminal epithelial cells and rarely in the pleomorphic myoepithelial cells. Glial fibrillary acidic protein positivity was commonly found in myoepithelial cells, myxoid matrices, and intracystic materials, but not in luminal epithelial cells.