Induction of c-fos mRNA by D dimer. Subconfluent rat lung fibroblasts were incubated in 0.4% serum for 48 hours followed by incubation with either fibrinogen or D dimer (1 μmol/L) in serum-free media for 15 to 60 minutes as indicated. Northern blotting of the RNA was performed as described in Materials and Methods. Autoradiogram bands were analyzed by phosphorimagery. Data are plotted as the mean + SE of the band density relative to that of SFM alone (n = 3/time point). (A) Representative autoradiogram. SFM, FBS, FGN, and D dimer denote the mRNA from serum-free media, 10% fetal bovine serum, fibrinogen, and D dimer-exposed cells, respectively. (B) Fold induction of c-fos/18S RNA (loading and transfer control) band intensity values relative to that of cells incubated in serum-free media. (□) Fibrinogen-exposed cells; (▪) D dimer-exposed cells.