Fig. 4.
Effect of TPA on the proliferation capacity of U937 and RU cells. U937 or RU cultures (104 cells) were grown in 0.1 mL of complete medium with or without TPA (50 ng/mL). At indicated times, cultures were pulsed for 4 hours with 1 μCi of [3H]thymidine, and incorporated radioactivity was subsequently measured in a liquid scintillation counter (average values and SD bars from three independent experiments, each done in triplicate).