Clearance of thrombin-activated wild-type platelets. After treatment of biotinylated platelets with thrombin at 1 U/mL, activated (dotted line) or resting (solid line) platelets were injected into a mouse. The fraction of biotinylated platelets was quantified from time zero (<2 minutes after infusion) to 72 hours. The fraction of biotinylated platelets at time zero was called 100%. Platelet activation did not affect the rate of platelet clearance; n = 6. P-selectin–deficient platelets behaved in the same manner (not shown).