Erythrocyte capture by platelets and dependence on platelet activation state.

(A) One of many short-lived pausing events observed as washed erythrocytes were perfused over collagen-adherent platelets at a wall shear rate of 50 s⁻¹. Following capture, membrane tethering, and a pause for 400 milliseconds, the red cell was released by the platelet. Visualization of firmly adhered erythrocytes on fibrinogen-adherent platelets (B) or collagen-adherent platelets (C) demonstrated the dependence of RBC adhesion on platelet activation. Identical results were obtained in 3 separate experiments, each conducted with an individual donor. Flow was from right to left.