Effect of 1-(4-amino-2-methyl-5-pyrimidil)methyl-3-(2-chloroethyl)3-nitrosourea hydrochloride (ACNU) on glioma cells: ultrastructural observation using cell-cycle-specific cell sorting by flow cytometry

To assess the effect of 1-(4-amino-2-methyl-5-pyrimidil)methyl-3-(2-chloroethyl)3-nitrosourea hydrochloride (ACNU) on human glioma, we performed cell-cycle-specific cell sorting followed by electron microscopic observation. Cells sorted from an accumulated SG2M peak caused by treatment with 10μg/ml ACNU showed a number of cells similar to S-phase cells in the untreated samples, having no microvilli. Cell organelles were intact, and no ultrastructural evidence for cell injury was observed. In contrast, many cells sorted from nonstagnated G0G1 and SG2M peaks in the samples treated with 100μg/ml ACNU showed mitochondrial swelling that suggested cell necrosis.