Effect of shear on tether length and stability.

(A) Single-cell analysis of tether length as a function of shear. A membrane tether is pulled from a single platelet over a 50-second time period after which the tether length is maintained. Increasing the wall shear rate from 150 s⁻¹ to 600 s⁻¹ to 1800 s⁻¹ results in a corresponding increase in tether length. After 80 seconds at 1800 s⁻¹, the tether detaches, allowing the cell to reinitiate translocation. (B) Washed platelets were perfused through VWF-coated microcapillary tubes at 150 s⁻¹ for 5 seconds, after which the wall shear rate was either maintained at 150 s⁻¹ or increased to 600 s⁻¹, 1800 s⁻¹, 5000 s⁻¹, or 10 000 s⁻¹ for analysis of tether length. The maximal tether length was determined immediately prior to release of the tether attachment point. These results are from 4 independent experiments (P < .05; P < .001).