Canadian journal of comparative medicine and veterinary science最新文献

The paper describes observations on the distributions of the P, QRS and T cardiac vectors in the horizontal plane in 377 apparently healthy horses. The possible usefulness of vectorcardiography in the clinical evaluation of cardiac function is briefly discussed.

In the present investigation 42 female ferrets were studied in regard to the influence of canine distemper in this species on gastric acid secretion. A total of fifteen naturally-infected and 27 non-infected ferrets were fasted and pylorus-ligated, and were either injected with corticosterone (10 or 50 mg/kg, s.c. one injection/day for 4 days) suspended in corn oil, injected with corn oil, on non-injected. Prior to autopsy blood samples were acquired for corticosterone analysis, and at autopsy the volume, pH, free and combined acidity of the gastric contents were evaluated. It was apparent that distemper induced hypochlorhydria in ferrets under the conditions of these experiments, an effect which was probably mediated through the central nervous system, but may also relate to a direct effect of distemper virus upon the gastric mucosa. Administration of corticosterone did not prevent hypochlorhydria in distemperous ferrets. Blood levels of corticosterone were elevated due to the stress effect of distemper infection, and also as a reflection of exogenous corticosterone administration. Prior immunization against canine distemper failed to immunize the ferrets in this study against the natural precipitation of this disease.

The presence of antibody was detected by agglutination tests in the serum of calves four days after vaccination with Brucella abortus strain 19. Titres had reached a maximum by seven to ten days post-vaccination. Sucrose density-gradient ultracentrifugation demonstrated that the earliest antibodies were macroglobulins, IgM (19Sgamma; gammaM)-globulins. Lighter antibodies, IgG (7Sgamma(2); gammaG)-globulins, appeared a few days later. With time, antibody titres fell, IgM declining somewhat more quickly than IgG. After revaccination some seven months later, there was a rapid rise in both IgM and IgG.Anion-exchange column chromatography (DEAE-cellulose) and gel filtration (Sephadex G-200) were applied in separating the two forms of antibody. The former method, in which a gradient buffer system was used, proved to be the more efficient; the IgG antibodies apeared in early eluates at pH 7.8 to 8.0 and low ionic strength, 0.03M, whereas IgM was eluted late when the pH had fallen below 6.0 and the molarity had increased to beyond 0.2. DEAE cellulose chromatography detected IgG as well as IgM sera collected as early as five days after vaccination.

A respiratory condition encountered in young turkeys is reported with the isolation of Bordetella bronchiseptica as the possible etiological agent. Rhinitis, bronchitis and bronchopneumonia were the main lesions caused by this bacteria. Transmission trials were successful in turkeys and chicken but not in mice. Guinea pigs were also infected for comparative pathological studies.

Three strains of rabies virus, one fixed and two street, were compared for invasiveness in neurectomized rats following foot pad inoculation. Approximately one-fifth of test rats studied revealed that the virus bypassed the severed sciatic and saphenous nerves and reached the brain. All rats dying within 20 days were positive for rabies upon fluorescent antibody and mouse mortality tests. Viremia was demonstrated in 20 per cent of both neurectomized or non-neurectomized rats one hour after inoculation of rabies virus, both fixed and street strains, into the foot pad.

The turnover of I(131)-labelled IgG has been studied in cattle with mild hypoimmunoglobulinemia secondary to gastrointestinal disorders. A gastrointestinal loss of immunoglobulin was the most likely cause of the hypoimmunoglobulinemic condition. Thus, 6 animals with severe digestive symptoms (diarrhoea) had increased turnover rates of I(131)-IgG, whereas animals that had recovered from diarrhoeal diseases had normal or even low turnover rates (table I). It is concluded that the pattern of immunoglobulin metabolism is closely related to the clinical picture of the digestive disease.