Fig. 2.

Platelet accumulation after laser injury in wild-type and Par4^−/− mice. Platelets were labeled as in Fig. 1. (A) Median integrated platelet fluorescence for 33 thrombi in four wild-type mice and for 30 thrombi in three Par4^−/− mice plotted versus time after laser-induced injury of the cremaster arteriole vessel wall. (B) Distribution of the integrated platelet fluorescence for each of the 33 thrombi in wild-type mice and 30 thrombi in Par4^−/− mice at 16 s after injury. No significant difference is seen between the thrombi in the two genotypes by the Wilcoxon rank sum test (P < 0.33). (C) Distribution of the integrated platelet fluorescence for each of 33 wild-type and 30 Par4^−/− thrombi at maximal size. Wild-type thrombi are significantly larger than Par4^−/− thrombi by the Wilcoxon rank sum test (P < 0.0001). (D) Distribution of the maximal integrated platelet fluorescence for each thrombus in both genotypes placed in order of ascending thrombus size. Fifty-nine wild-type thrombi and 56 Par4^−/− thrombi were ranked for determination of the quartile distribution. The percentage of thrombi of each genotype was determined independently in each quartile of the rank order. Black bars, wild-type; gray bars, Par4^−/−.