Figure 2:Induction of late apoptotic cells and mitochondrial membrane potentials in peripheral blood mononuclear cells (PBMCs) treated with nevirapine and efavirenz using different concentrations. The changes in late apoptotic cells (A) and mitochondrial membrane potential (B) from untreated cells in each treatment condition are shown with open bars (nevirapine) and closed bars (efavirenz). Significant differences were observed when the cells were treated with x2.0 Cmax of efavirenz. No data are shown in cells treated with x4.0 Cmax of efavirenz because of the low number of viable cells after 48 hr incubation. Cmax: the mean peak steady-state levels in human plasma during antiretroviral therapy. Actual FACS figures for late apoptotic cells (C) and cells with active mitochondrial membrance potential (D) are shown. (C): The viable cells were gated (Panel C-A) and the proportion of late apoptotic cells which were defined as positive for both Annexin-V and propidium iodine (PI) are indicated at the right upper corner of the panel for late apoptotic cells: untreated cells (Panel C-B), vehicle (50% ethanol concentration used for efavirenz x2.0 Cmax, Panel C-C), nevirapine treated cells with different concentrations (Panels C-D, E, F), and efavirenz treated cells with different concentrations (Panels C-G, H, I). (D): The viable cells were gated (Panel D-A) and the proportion of cells with mitochondrial membrane potential were defined as positive for DiIC1(5) and negative for PI are indicated at the left upper corner of the panel for cells with mitochondrial membrane potential: untreated cells (Panel D-B), vehicle (50% ethanol concentration used for efavirenz x2.0 Cmax, Panel D-C), nevirapine treated cells with different concentrations (Panels D-D, E, F), and efavirenz treated cells with different concentrations (Panels D-G, H, I). Cmax: the mean peak steady-state levels in human plasma during antiretroviral therapy. PI: propidium iodine.