Fig. 5.
Release of PF4 after platelet activation.
Either 650 μL citrated platelet-rich plasma (300 × 106 platelets/mL) was not activated or it was activated with heparin and HIT IgG, collagen and heparin together, collagen alone, or heparin alone after being stirred in an aggregometer. Activation was arrested when ETP was added and the plasma was chilled on ice. Platelets were removed by centrifugation (for use in the step described in Figure 6), and the plasma PF4 concentration was measured by competition radioimmunoassay. Bars show the mean values of 3 experiments.
