[Combined study of leukemic blasts using DNA autoradiography and cytophotometry]

The 3H-thymidine incorporation capacity and DNA contents were studied in the same bone marrow blasts in 4 patients suffering from acute leucaemia. The blast populations were both proliferating and non-proliferating. Actively proliferating cells were blasts of large and medium diameters. Mitotically inactive cells were blasts of medium and small diameters. Cells that stopped dividing were established as being in period G1 of the cell cycle. A high variation in DNA contents was noted in blasts unlabeled with 3H-thymidine, a possible reason of the above phenomenon being discussed.