Hemostatic and thrombotic properties of plasma VWF^{I1309V, R1326H}. (A) Tail bleeding times for WT and mutant VWF-A1 mice. Each point represents 1 individual animal; lines show the mean of each group. (B) Thrombus formation in laser-injured arterioles of WT and VWF mutant animals (n = 7 mice per genotype; 1 arteriole per mouse). Platelet-vessel wall interactions were visualized through a ×20 water-immersion objective (Olympus LUMPlanFl, 0.5 NA) using a Zeiss Axiotech Vario microscope equipped with a Yokogawa CSU-22 spinning disk confocal scanner, iXon EM camera, and 561 nm laser line to detect rhodamine-labeled mouse platelets (Revolution XD, Andor Technology, South Windsor, CT). The extent of thrombus formation was assessed for 2 minutes postinjury and the area (µm²) of coverage determined by off-line analysis (Image IQ, Andor Technology and Image-Pro Plus). (C-D) Accumulation (C) and translocation velocities (WSR of 1,600 s⁻¹) (D) of mouse platelets on surface-immobilized WT or mutant plasma VWF at the indicated WSRs (n = 3 separate experiments). Images were obtained using a CCD camera and analyzed using Image-Pro Plus. Data are the mean ± SD. *P < .05 and **P < .0001 relative to control. ns, not significant (P > .05).