Thrombus generation on a collagen-coated surface by normal control blood perfused under high or low shear rate. Upper panels: time-course images (taken at 1, 3, 5, and 7 minutes of perfusion) of platelet-surface interaction at 50 s−1 and 1,500 s−1, displayed as accumulated fluorescence, are representative of 10 independent perfusions with blood from 10 individual donors. At either shear rate, the images at 1 minute after the beginning of perfusion indicate superficial platelet adhesion. Platelets adhering to the surface gradually assembled to form mural thrombi as a function of time. Mural thrombi formed under a shear rate of 1,500 s−1 appear to cover much more surface area than those found under 50 s−1. Lower panel: computer-assisted evaluation of amount of platelets adhering to the surface, corresponding to the images displayed above.
