Functional effects: cell death and T-lymphocyte proliferation. (A) PBMCs were treated with khat (k 10-3 and 3.16 × 10-4 dilutions), 10-4 M of cathinone, cathine, norephedrine (n = 14), and a combination of the latter three (n = 7) for 6 hours. The PBMCs were stained with Annexin V-FITC and PI, and analyzed by flow cytometry. The results are expressed as percentages viable (Annexin V-PI-) and apoptotic (Annexin V+PI-) cells of the total cell number analyzed. (B) PBMCs were treated with khat (10-3 and 3.16 × 10-4 dilutions) and 10-4 M of cathinone, cathine, norephedrine (n = 14) and a combination of the latter three (n = 7). Nuclear radioactivity following 3H-thymidine incorporation was assayed by liquid scintillation counting after four days. Results are expressed as percent average counts per minute (CPMA) in treated cells relative to the CPMA in control cells. * denotes p <0.008 and ** denotes p <0.001.