bFGF effect on EryP colony development. (A) EBs at different days were replated in methylcellulose culture with bFGF at various concentrations in the presence of heparin (10 μg/mL). Each point represents an average number obtained from 3 different plates. Error bars indicate standard deviations of numbers obtained from 3 different plates. (B) EryP numbers obtained with bFGF and Epo were shown as a relative percent of those obtained with Epo only. Results obtained from 3 independent experiments with EBs at different time points (day 2.625 to 4.75) are shown.