Spontaneous lesions detected in the beagles used in toxicity studies.

Four hundred and twenty beagles 1 to 4 years of age were examined for spontaneous pathological changes. In the liver were seen fine granular gallstones (87.5%), granulomas (59.9%), intranuclear hyaline inclusions (52.6%), lipofuscin deposition (50%) and eosinophilic inclusions (3.7%) in the cytoplasm of hepatocytes and parenchymal necrosis at the base of the ligaments (7.3%). Intranuclear hyaline inclusions and lipofuscin deposition were more frequently seen in dogs after being subjected to tests for more than 13 weeks. Besides, hyperplasia of follicular epithelial cells of the thyroid gland (46.3%), Gandy-Gamna like bodies of the splenic capsule (43.1%), small cysts in the anterior lobe of the hypophysis (35.1%) and prostatitis (13,7%) were observed. Lesions due to migration of Toxocara canis larvae were detected in the liver, kidney, lung and other organs from 33.1% of cases examined.