Fluorescent images of platelets adhering to vWF-coated and collagen-coated surfaces. Mepacrine-treated blood was passed through the flow chamber at the shear rate of 800/s. Fluorescent patterns were captured at 0.5, 1, and 2 minutes after the start of flow. On the vWF-coated surface, platelets adhered mainly as single platelets, but some small aggregates were observed (arrows). Bars shown in the upper left corner in the top row indicate a length of 50 μm.