Time- and dose-related assay of caspase 3 activity in PTEC. (A) Up-regulation of caspase 3 activity by PTEC cultured with Aldo (10-10 M), AngII (10-10 M) or 4 fold diluted IgA-HMC medium prepared from IgAN patients (medium-IgAN); Similar up-regulation was not observed with IgA-HMC medium from controls (medium-Ctl) or pIgA alone (IgA). (B) Dose-dependent up-regulation of caspase 3 activity by PTEC cultured with Aldo, AngII or IgA-HMC medium prepared from IgAN patients. * and ** signify p < 0.05 and p < 0.01 respectively when compared with data from time zero or from PTEC cultured in plain medium. The results represent the mean ± SD from five individual experiments.