Potentiation of BCNU-induced cytotoxicity by pretreatment with O⁶-BeG. Male B6D2F1 mice were pretreated with either corn oil or O⁶-BeG (30 mg/kg) in corn oil and 2 hours later treated with increasing doses of BCNU. Each data point represents the mean ± SE of at least three independent experiments. Marrows from three animals were pooled in each experiment. The data were analyzed with analysis of variance using MINITAB statistical software. Bone marrow cellularity and numbers of GM-CFC and CFU-S following the treatment with O⁶-BeG plus BCNU (▪) were significantly (P < .001) different from BCNU alone (•).