NB4 cell kinetics following treatment with CD437. NB4 cells were seeded at 200,000/mL in RPMI 1640 containing 10% FCS, allowed to enter the exponential phase of growth by incubation for 12 hours in the same medium. Subsequently cells were pulse-labeled with BrdU for 15 minutes as described in Materials and Methods before incubation with vehicle (DMSO), alone (Control), or with 10⁻⁶ mol/L CD437 for the indicated amount of time. Cells were analyzed for the content of DNA following staining with propidium iodide (horizontal axis) or for the amount of BrdU incorporated into DNA (vertical axis) by flow cytometry. Numbers below each panel indicate the percentage of BrdU-positive cells.