DF and N-mers substitute for heparin, which is required for the biologic activity of bFGF. C11 cells were washed twice with media without IL-3, and seeded (2.2 × 10⁴ cells/well in 48-well plates) in media containing 10% FBS but not IL-3. The cells were then treated with 1 nmol/L bFGF + DF (25 μmol/L, A) or 1 nmol/L bFGF + N-mers (1 μmol/L, B). After 2 days, proliferation was evaluated by SRB staining. Data are presented as the average plus or minus SD, n = 3. bFGF + Hep versus bFGF, P less than .05; bFGF + DF, N50, N60, or N80 versus bFGF, P less than .05; bFGF + N25, N30 versus bFGF, P = not significant. DF or Hep versus C, P = not significant. C = control, Hep = Heparin.