Serum and bFGF dose-dependent secretion of TFPI by PASMC. (A) Monolayers of quiescent PASMC were treated with basal medium alone (0) or with the basal medium containing varying concentrations of bFGF in the presence of a fixed concentration of heparin (15 U/mL). (B) PASMC were treated with basal medium alone (0) or varying concentrations (vol/vol) of serum. At the end of 48 hours, the conditioned media was removed and assayed for TFPI activity (n =3).