Blood clotting assays. In all panels, red bars refer to WT mice, and blue bars to APP-KO mice. Data are expressed as mean ± SEM of 10 different determinations. Quantification of the level of plasma fibrinogen in the 2 genotypes is reported in (A). PT (B,D) and APTT (C,E) was measured in PPP (B-C) and PRP (D-E). *P < .05. (F) Measurement of APTT in reconstituted samples obtained by mixing PPP from 1 genotype with washed platelets from the other genotype, as indicated. *P < .05. (G) Quantification of the activity of FXIa (i) and FXIIa (ii) in PRP from WT and APP-KO mice. *P < .05.