Roundness versus area plot of VWF molecules in function of shear stress.

The stacked graphs representing data from 4 experiments are shown (A,C,E,G: low shear; B,D,F,H: high shear). After 5 minutes of VWF perfusion over collagen surface, size distribution of gold bead–covered area is similar at low (A, 1st experiment; C, 2nd experiment) and at high shear (B, 1st experiment; D, 2nd experiment), but some very large molecules are present only in the latter case (points at the right side of B and D). Cloud plots for the roundness versus area graphs show that irregularity of VWF molecules seems to correlate with their area size, and highly irregular molecules are also unusually large. When perfusing for 15 minutes, such large molecules could not be detected anymore, neither in the absence (E-F) nor in the presence (G-H) of fixed platelets in the perfusate. AFM parameters are identical to those in Figure 1.