In vivo analysis of thrombosis and hemostasis. (A–C) Mesenteric arterioles were treated with FeCl₃, and adhesion and thrombus formation of fluorescently labeled platelets were monitored by in vivo video microscopy. Representative images (A), the time to appearance of the first thrombus >20 μm (B), and the time to vessel occlusion (C) are shown. Each symbol represents one individual. The asterisk in A indicates occlusion of the vessel. Horizontal bars in B represent means. Bar, 50 μm. (D and E) The abdominal aorta was mechanically injured, and blood flow was monitored for 30 min or until complete occlusion occurred (blood flow stopped >5 min). (D) Representative cross sections of the abdominal aorta of mice with wild-type or Stim1^−/− platelets 30 min after injury. Bar, 250 μm. (E) Time to vessel occlusion. Each symbol represents one individual. (F) Tail bleeding times in wild-type and Stim1^−/− chimeras. Each symbol represents one individual. Videos 1 and 2 are available.