The values are mean ± S.D. of an experiment performed in triplicate. Similar enhancements were obtained in three additional individual experiments. In each condition, 2.1 × 10⁷ PBMC (mean ± S.D.; cell volume, 190 ± 50 fl) were first incubated at 37°C for 15 min without or with 5 mM NEM or 5 mM DA. At the end of the incubation period, cisplatin was added to a final concentration of 5 μM, and the incubation continued at 37°C for 2 h. DNA was then extracted, and Pt adducts were determined on AAS. Moreover, in parallel samples, the concentrations of cellular GSH at the end of the 15-min incubations were determined as described underMaterial and Methods.