nantitation of Fernoral Bone Marrow Cellularity of Rats with Acute Chioroleukemia

By EVELYN E. VARSA, EUGENE S. HANDLER AND ALBERT S. CORDON W HILE INDIRECT ATTEMPTS to quantitate granulocyte reserves in leukemic human subjects1 and laboratory rats4 have been reported, direct approaches toward quantitation have been limited by the availability of experimental animals and the facility of obtaining homogeneous samples. Shay et al. developed a myelogenous leukemia in Wistar rats following gastric instillation of 20-methylcholanthrene and Harris et al.6 described the pathogenesis of the leukemia after intraperitoneal transfer of cells in pups less than 7 days old. Rosin and Zajicek7 were successful in serially transferring the leukemia into young adult rats ( 80-160 Gm. ) via intravenous injections of leukemic cell suspensions. The pathogenesis of the disease differs depending on the route of administration. Thus, a chronic myelogenous leukemia is evident after intraperitoneal injections, while an acute leukemia appears following intravenous inoculation. N’Ioloney et al.TM have related the morphology and histochemistry cf the chloroma cell with the characteristics of cells found in human myelogenous leukemias. A constant aberrant chromosome number of 43 in serially transplanted chioroma cells has been demonstrated.9 Similarities to certain human leukemias and a stability displayed throughout the course of numerous transplant generations make the Shay chioroleukemic rat an ideal experimental animal. The present investigation was designed to quantitate femoral bone marrow cellularity during the progress of this acute leukemia in rats and to develop a uniform leukemic animal for future experimentation.