A naturally occurring malignant canine venereal tumor in the vagina of a mature Collie dog did not regress following surgical intervention. The tumor progressed fatally over a period of 5 weeks and metastasized to the inguinal and iliac lymph nodes, spleen, eye, and brain. It had a modal number of 60 chromosomes of which 17 were metacentric.
The present study was undertaken to determine the effects of beta-carotene on corn oil-induced superoxide dismutase and catalase. Six groups of male Buffalo rats were fed the following diets for 6 wk: a control diet containing recommended levels of beta-carotene and retinyl palmitate, a retinol diet containing 10 times the recommended level of retinyl palmitate, and a beta-carotene diet containing 10 times the recommended levels of beta-carotene and adequate levels of retinyl palmitate. Each vitamin combination was fed with either 5% (wt/wt) corn oil (low fat) or 20% corn oil (high fat). Plasma total beta-carotene levels were highest in the beta-carotene groups. Levels varied inversely with the level of fat in the control group and directly with fat in the beta-carotene group. Transport of beta-carotene appeared to parallel that of cholesterol in that 36 and 35%, respectively, were associated with the low density lipoprotein fraction. Accumulation of beta-carotene in the liver was apparent from the observation that levels in liver were much higher than those in plasma. Superoxide dismutase activity was much lower in the beta-carotene groups than in the retinol groups, irrespective of level of fat, and catalase activity was also lower in the beta-carotene group, but it was in proportion to the level of fat. These findings suggest that beta-carotene functions as an antioxidant in vivo.
6-Mercaptopurine monohydrate was injected sc at 2 mg base/kg/day from 2 to 22 days of age to four litters of rat pups (four females, four males per litter). Control neonates were injected sc with basic saline (pH 8). Daily observations for signs of toxicity were made during the treatment period and once weekly thereafter until the rats were 6 months of age. The pups were weighed at 2, 12, 23, 34, 100, and 480 days of age. Fertility was tested at 3 to 6 months of age. From 6 months of age on, the rats were examined for tumors at 3-month intervals until the experiment was terminated at 16 months of age. A reduction in body weight of treated rats began between 34 and 100 days of age and became more pronounced by 16 months of age. Fertility was similar in treated and control groups and there were no detectable tumors in either group. The major finding in treated rats was a delayed onset of hind leg paresis that was first detected at 12 months of age. Light microscopic examination of tissues taken from the hind quarters of these rats at 16 months of age revealed a severe atrophic degeneration with fatty infiltration of sublumbar and thigh muscles.
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