Effects of FN on the clonogenic efficiency of EML-C1 cells. (A) Cytocentrifuged preparations of the colonies generated in the presence of SCF alone or SCF + IL-3, with or without FN, respectively, were photographed after Giemsa staining. (B) After exposure to FN, EML-C1 cells (1.0 × 10³) were plated in methylcellulose media containing SCF alone or SCF + IL-3. The number of CFU-Blast and CFU-GM were assessed on day 14 and day 7 of culture. The data represent mean ± SD of triplicate cultures and statistically significant differences from control (BSA) values are indicated by two (P < .01) asterisks. Similar results were obtained in three independent experiments.