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alpha-Mannosidase and beta-N-acetylglucosaminidase activities were found to differ between lymphocytes and granulocytes isolated from bovine blood. Activities of both enzymes in granulocyte preparations were found to be related to the eosinophil content of the preparations. A procedure is described that allows definition of the mannosidosis genotype of adult cattle by giving consideration to the influence of eosinophil content of granulocyte preparations upon the activity of alpha-mannosidase relative to that of beta-N-acetylglucosaminidase.

Mannosidosis, an inherited and lethal lysosomal storage disease of Aberdeen Angus cattle, was diagnosed on a farm in north-east Scotland. Two affected calves were examined in detail. Both were poorly grown and ataxic, though the intention tremor and aggression considered characteristic of the disease were not recorded. Histological examination revealed typical vacuolation of nerve cells, fixed macrophages and epithelial cells of the viscera. Deficiency of the enzyme alpha mannosidase was demonstrated. The epidemiology of the disorder in Scotland is considered and control methods indicated.

Several kittens in a family of Persian cats had a metabolic storage disease. Clinically the disorder was characterized by hepatomegaly, neurological signs and early death. The microscopic lesions consisted of widespread vacuolation of neurons and glial cells in the central nervous system and in liver cells. Electronmicroscopically the lesions consisted of intracytoplasmic accumulation of membrane-bound "empty" vacuoles. In addition to the storage disease, poor myelination of the cerebral white matter was found. The defect was reproduced in breeding trials. On biochemical analysis of brain tissue, deficient function of the enzyme alpha-mannosidase was detected. The clinical and pathological features of mannosidosis in Persian cats were compared to similar defects in other species.