Figure 1
Labeling pattern of leukemic cells in marrow of patient 1. Patient 1, a patient with acute myelomonocytic leukemia, received a continuous 10-day infusion of tritiated thymidine. Leukemic cells were arbitrarily divided into types I, II, and III based on increasing levels of morphologic maturity (type I indicates primitive blast forms; type III, most differentiated cells). At the end of the 10-day infusion, most type II and type III cells were labeled in both marrow (shown here) and blood (not shown), but only 40% of type I cells were labeled, reflecting their slow proliferative rate. Many of the type I cells remained highly labeled for over 3 weeks after the infusion. Reprinted from Clarkson17 by permission.
