Fig. 3. VEGF increases the size and prolongs the life span of Ery^P. (A) Size distribution of Ery^P. EBs were dissociated on day 7 and assayed into hematopoiesis at 2x10⁴ ml^–1. Colony size was determined by integrating the area of individual colonies using the Northern Eclipse software. The range covered by columns are equivalent and are determined arbitrarily. –VEGF, n=50; +VEGF, n=53; P<0.003. (B) VEGF prolongs the life span of Ery^P. Day-3 Ery^P, derived from either VEGF-treated (5 ng ml^–1) or untreated day-7 EBs, were transferred individually into 96-well plates containing fresh medium. Viability was assessed by visual inspection. Cells were considered nonviable when lysed or necrotic (n=121). Histogram represents the percentage of day-3 Ery^P that were viable 3 days after transfer. Histogram depicts pooled data from two independent experiments. (C) VEGF stimulates blast-colony formation (BL-CFC). Day-3 or day-3.5 EBs derived from R1 ES cells were assessed for BL-CFC in the presence or absence of VEGF. Results are the mean±s.d. of duplicates.