Fig. 7.

Survival-promoting effects of FGF-2 depend on normal biological activity. Determination of relative percentages of surviving PRs and treatments were performed as in Figure 5. Treatments consisted of CDM alone (controls), FGF-2 (20 ng/ml), heat-inactivated (FGF-2_in) FGF-2 (20 ng/ml), suramin (50 μm) plus FGF-2 (20 ng/ml), EGF (10 ng/ml), and tyrphostin-23 (10 μm) plus EGF (10 ng/ml). Although FGF-2 led to increased survival and EGF led to decreased survival as above, inactivated FGF-2 was without effect, suramin addition suppressed the effects of FGF-2, and tyrphostin suppressed the effects of EGF, after 5 d in vitro. Error bars are SEM (n = 4). Statistical treatments:asterisks above FGF-2 and EGF are with respect to controls: **p < 0.01, ***p < 0.001. Small circles aboveFGF-2_in and suramin + FGF-2 are with respect to FGF-2 alone: °°°p < 0.001. The small plus sign above Tyrphostin + EGF is with respect to EGF alone: p < 0.05. Suramin and tyrphostin when tested alone did not influence survival (data not shown).