Parmodulin 2 inhibits thrombus formation without prolonging bleeding times. (A) Platelet-specific anti-GPIbβ antibody conjugated to Dylight 649 (0.1 µg/g body weight) was infused into mice. Thrombi were induced by laser injury of cremaster arterioles before (n = 62 thrombi in 7 mice) and after (n = 54 thrombi in 7 mice) infusion of parmodulin 2 (5 mg/kg body weight). Thrombus formation was visualized by videomicroscopy for 180 seconds after injury. Representative binarized images of platelets at the injury site before (Control) and after parmodulin 2 infusion (PM2) are shown. White arrowheads indicate the location of the vessel. (B) Median integrated platelet-fluorescence intensity at the injury site in mice before (Control) and after parmodulin 2 infusion (PM2) is plotted over time. (C) Mouse platelet aggregation in response to 65 μM AYPGKF was evaluated after incubation with the indicated concentrations of parmodulin 2. (D) Time to cessation of bleeding and (E) total hemoglobin loss was measured after tail-tip amputation.