Adhesion of α_IIbβ₃-inhibited platelets to collagen type III under flow conditions; increased adhesion by the thrombin-generating system is independent of tissue factor.

Washed normal platelets and red cells (200 000 platelets/μL; hematocrit 40%) were perfused over collagen type III for 5 minutes at 1600 s⁻¹ in the presence of an RGD-containing peptide (rRGDW; 200 μM) in the absence (A) or presence (B-C) of the thrombin-generating system (1.2 μg/mL rFVIIa, 10 μg factor X, 20 ng/mL prothrombin, 3 mM CaCl₂). In panel C both the surface and the platelet suspension were preincubated with inhibitory tissue factor IgG. Original magnification × 400 for panels A-C.