An asterisk (*) indicates a statistically significant difference. a, b, Effect of ex vivo treatment of WBM (2 h on ice) with ethanol control (red) or dmPGE2 (1 μM per 106 cells) on CFU-S8 and CFU-S12 (60,000 cells per recipient; CFU-S12: two-tailed t-test, control (mean/s.d./n) = 5.78/2.73/9, dmPGE2 = 15.22/2.39/9, P < 0.0001). c, Effect on CFU-S12 following ex vivo treatment with indomethacin (1 μM per 106 cells) (100,000 cells/recipient; two-tailed t-test, control (mean/s.d./n) = 8.8/2.10/10, indomethacin = 2.5/1.43/10, P = 0.0001). d, CFU-S12 evaluation after treatment of cKit+Sca1+Lineage- stem cells with dmPGE2 or ethanol control (two-tailed t-test, 100 cells: control (mean/s.d./n) = 3/1.63/4, dmPGE2 = 6.2/1.3/5, P = 0.013; 300 cells: control (mean/s.d./n) = 5/1.22/5, dmPGE2 = 11/1.87/5, P = 0.0003). e, f, Limiting dilution competitive repopulation assay. The number of negative recipients as determined by FACS analysis (e) in relation to the total number of cells transplanted for control or dmPGE2-treated cell samples is shown at 12 weeks. P0 = 67,884 (control) and 16,970 (dmPGE2 treated). The frequency of engraftment (f) at 6, 12, and 24 weeks post transplantation in recipients of ethanol- versus dmPGE2-treated WBM calculated by Poisson statistics (ANOVA, n = 10 per variable; 6 wks, P = 0.005; 12 wks, P = 0.002; 24 wks, P = 0.05); the number of recipients surviving to analysis at each time point is shown in .