Apoptosis pattern and G-CSF effect on survival of hESC-Neu's. (A) Flow cytometric analysis. In the steady state, PB-Neu's have a short life span of approximately 24 hours, but this can be prolonged by G-CSF stimulation (i-v). Some hESC-Neu's were already apoptotic at the time of the harvest from the induction culture (vi). In contrast to the PB-Neu's that underwent apoptosis within 6 hours without G-CSF (ii), the proportion of apoptotic cells did not increase for up to 6 hours after the start of the culture of hESC-Neu's in the medium without G-CSF (vi,vii). In addition, there were no differences between the cultures of hESC-Neu's with and without G-CSF for up to 6 hours (vii). After 6 hours, nonapoptotic cells decreased more rapidly among hESC-Neu's without G-CSF than among hESC-Neu's with G-CSF (viii-x), resulting in the lower number of viable cells than hESC-Neu's with G-CSF at 24 hours (x). Figures are representative of 3 independent experiments. Data are presented as mean plus or minus SD (n = 3). (B) The time course of the decrease in viable cells. Bars represent SDs (n = 3).