Perturbation of Generation Cycle of Human Leukaemic Blast Cells in vivo by Daunomycin

Abstract

The in vivo effect of daunomycin on the cell kinetics of leukaemic blast cells has been investigated in 4 patients with acute myeloblasts leukaemia and in 2 patients with acute lymphoblastic leukaemia by a method of combined autoradiography and microspectrophotometry. After a dose of about 1.5 mg daunomycin/kg bw a decrease in the mitotic index was observed, and in 4 cases also a depression of the in vitro 3 H‐thymidine labelling index was noticed. Microspectrophotometric analysis showed an accumulation of cells in G 2 phase and a depression of DNA synthesis. In 3 of the patients studied a rapid decline in the peripheral blast cell count was noticed. The data indicate that the effect of daunomycin on cell proliferation is a randomized cytocidal effect, superimposed on which there is a specific inhibitory action on the progression of cells through G 2 phase and a depression of DNA synthesis.