Pathology of radiostrontium exposure in cats

Thirty-three cats of two age groups were fed one of three dosage levels of ${}^{89}{\rm Sr}$ for 30 days. Twenty-four died or were killed before 107 days after the experiment was started. Mortality and bone marrow lesions were dose related. All cats had varying degrees of a hemorrhagic disease with hemorrhages most commonly observed in the heart, subcutis and intestines. Histologically, bone marrows of cats dying before 35 days postexposure were depleted of cells. Those dying later had cellular marrows composed predominantly of erythropoietic precursors. Myelofibrosis was seen in 5 cats and myeloid metaplasia, primarily in lymph nodes, developed in 6 cats. Dysplastic lesions occurred in the epiphyseal plate and metaphysis of long bones. Other lesions included atrophy of the thymus and lymphoid tissues and bacterial lesions in several tissues. Ultrastructural studies of bone marrow of 4 cats revealed degenerative changes in mitochondria of plasma cells and the presence of abnormal erythrocyte precursors. C...