Time course in TF activity expression and TF mRNA levels during incubation of HUVEC with monocytes, IL-1β, or TNF-α. HUVEC (2 × 10⁵/well) were incubated with monocytes (4 × 10⁵/well) (A), IL-1β (1 ng/mL) (B), or TNF-α (1 ng/mL) (C) for the indicated time intervals. At the end of incubation the cells were treated for TF activity assay as described in Materials and Methods. In a parallel set of samples total RNA was extracted from cells, and equal amounts of RNA were analyzed by Northern blot as described in Materials and Methods. Each point represent the mean of four experiments ± SEM. **P < .01, and *P < .05 versus time zero.