Intranephronic calculosis in the Brazilian squirrel monkey.

Brazilian squirrel monkey kidneys removed before and after administration of parathormone were studied by microdissection, polarizing microscopy, alizarin red and von Kossa's stains, and microchemical analysis. Intralumenal crystalline-matrix masses were observed in both groups but were increased in frequency after parathormone administration. Specific staining showed the presence of calcium and phosphorus, and specific chemical tests suggested the presence of uric acid or urate salts. Refractile alizarin red positive droplets were observed in the tubular cells of the pars convoluta in parathormone-treated animals. Urinary stone formation in these animals is unique in that the location and types of stones produced are similar to that seen in man. The squirrel monkey is a good experimental model to study renal stone disease and further studies of its etiology, structure, composition, and means of control should be performed.