Improved rapid autoradiography with elimination of background

A new method for studying cell cycle characteristics in ANLL using double-labeling with BrdU and 3HTdr

Ten patients with acute nonlymphocytic leukemia (ANLL) received bromodeoxyuridine (BrdU) at 100 mg/M2 intravenously over 1 h. BrdU is incorporated into the DNA by S-phase cells and was detected by using a monoclonal anti-BrdU antibody in the bone marrow aspirate (BM) and biopsy specimens obtained at the end of the infusion. Additionally, BM was incubated in vitro with tritiated thymidine (3HTdr) and processed by our previously described double-label method. This allowed us to measure the duration of S-phase (Ts) and total cell cycle time (Tc) of myeloblasts. Data revealed a higher number of S-phase cells from biopsies (21%) than BM (5%). The Ts ranged from 9 to 35 h and Tc ranged between 36 and 152 h in different patients. Using this method, data are available within 48 h and if shown to be clinically relevant, may be useful for prospective planning of therapy in individual patients.

Analysis of cell cycle characteristics and course of the disease in ANLL

The cell cycle characteristics of a newly diagnosed patient with acute nonlymphocytic leukemia (ANLL) were studied by using intravenous bromodeoxyuridine (BrdU) and our previously described "double-label" technique. The percentage of S-phase cells in the bone marrow (BM) biopsy were 25% compared to 7% from the simultaneously obtained BM aspirate. The duration of S-phase (Ts) was determined to be 4 hr and the total cell cycle time (Tc) was 16 hr. We demonstrated that the actual clinical course of this patient's illness corresponded well with the course predicted on the basis of these cell cycle measurements. Although he achieved aplasia in response to two successive courses of induction chemotherapy, leukemic cells repopulated the marrow, producing a rapidly rising PB white blood cell (WBC) count with a T1/2 of approximately 20 hr each time. It is likely that the resistance of this patient's leukemia to therapy was a result of the rapid proliferative rate of his leukemic cells and not due to the inability of chemotherapeutic agents to kill a large number of cells. Since the measurements can be completed within 48 hr, measuring Ts and Tc will provide a better understanding of the biological differences that exist between patients with ANLL.