THE EFFECT OF CERTAIN CYTOTOXIC AGENTS ON THE PROLIFERATION OF BONE-MARROW CELLS OF CHICKENS WITH ERYTHROLEUKEMIA

The results of an investigation of the effects of cytotoxic agents on the incorporation of H-3-thymidine into DNA of bone marrow cells of no rmal chickens and those with acute erythroleukemia induced by C-type o ncorna virus are presented. The agents included cytosine arabinoside, cyclophosphamide, mechlorethamine, doxorubicin and daunorubicin, in co ncentrations from 1-1000 mg per 2 m of bone marrow cell culture. Cytos ine arabinoside, mechlorethamine, doxorubicin and daunorubicin showed a concentration dependent inhibition of DNA synthesis in normal cells, which was significantly more marked in leukemic cells. Cyclophosphami de did not induce inhibition of DNA synthesis of either normal or leuk emic chicken bone marrow cells. The two highest concentrations of cyto toxic agents, which were shown to be significantly more efficient than lower ones, did not differ in their effect on either type of bone mar row cell, although the magnitude of the effect was significantly great er on leukemic cells. The results obtained in this in vitro study, on bone marrow cells of normal chickens and chickens with experimental ac ute erythroleukemia, indicate the possible usefulness of such investig ations on the proliferative activity of hematopoietic cells of patient s with leukemia in order to select the most suitable type and dose of cytotoxic agents.