Ultrastructural and biochemical features of AML leukemic blast cells after 2 days of exposure to solvent control or lovastatin. (A) A nonresponsive primary sample (patient A) and (B) a sensitive primary sample (patient O) were evaluated. (A) (a and b) Control blast cells; (c and d) 20 μmol/L lovastatin-treated blast cells from patient A displayed a number of large lysosomal granules. (B) (a and b) Control blast cells; (c) 20 μmol/L lovastatin-treated blast cells from patient O also displayed a number of large lysosomal granules in the few surviving cells; (d) 20 μmol/L lovastatin induced a prominent apoptotic response in patient O. The bar represents 1 μm except in (B) (b), where it represents 3 μm. Multilaser flow cytometric analysis of reduced GSH and MMP in the AML primary cultures A and O exposed to 20 μmol/L lovastatin for 2 days and analyzed. Dual-parameter dot plots of GSH and MMP for each sample are also presented.