Effects of LPA or ADP on platelet thrombus formation under shear conditions. A suspension of platelets and red blood cells in the presence or absence of 100 nM plasma fibronectin (FN) or 5 μM LPA or ADP was perfused through a flow chamber opposed to a coverslip or culture dish coated with fibrin or fibronectin-fibrin for 5 minutes at a shear rate of 1250 s^–1. (A) Coverslips were taken out of the chamber, and microscopy was performed as described in Figure 1. Bar = 100 μm. (B-C) Thrombus volumes and platelet numbers were measured as described in Table 1. Values represent the mean ± SD (n = 3 experiments).