In vitro platelet adhesion and aggregation in the presence of heparin.
(A) Single-platelet adhesion. Either GP V+/+ (♦) or GP V−/− (▪) mice were bled with heparin-coated glass capillary tubes and thrombin was further inhibited by heparin (20 U/mL). Fluorescently labeled blood samples were then perfused at a shear rate of 1500 s−1 in a flow chamber coated with collagen type I fibrils. Numbers of adherent platelets in the first 15 seconds were very similar in the 2 genotypes. n = 2,P = .44, Mann-Whitney test. The mean and individual values are shown. (B) Comparison of volumes of platelet thrombi formed in the in vitro thrombosis model. Heparin-treated blood samples were perfused at shear rate of 1500 s−1 and total volumes of thrombi were determined after 60, 180, and 470 seconds. No significant differences were found between GP V+/+ (—) and GP V−/− mice (- - -). n = 3, P > .27 at all time points tested, Mann-Whitney test. The mean ± SEM is shown.
