Procoagulant phosphatidylserine exposure measured by prothrombinase assay after apoptosis induction in control and Scott cells. Cells were treated for 48 (a) or 72 (b) h, by 200 nM A23187 or 10 μM SKF 96365 in the absence or in the presence of z-VAD.fmk (50 μM), or for 10 min (c) by 1 μM A23187, as described in the "Experimental Procedures". Data are expressed as mean ± SEM of 5 independent experiments (each with duplicate samples), where □ represents the increase in activity with respect to baseline prothrombinase activity. *P < 0.05 versus 72 h A23187 treatment of Scott cells. §P < 0.05 versus the corresponding value obtained in the absence of z-VAD.fmk. †P < 0.05 versus the corresponding value obtained with control cells.