Circulating platelet counts in the arterial and venous blood during and after infusion of complement fragments. The counts between 0 and 20 minutes are shown in (A), and (B) shows the counts for the entire 2-hour duration of the experiment. The venous counts (□) decreased more slowly than the arterial counts (○) in the first 4 minutes of the infusion. The platelet counts in both the arterial and the venous blood samples remained low throughout the entire infusion. After the infusion was stopped, platelet counts in both arterial and venous blood increased similarly to baseline values by 45 minutes (30 minutes after the infusion was stopped). *Significantly greater than platelet counts in the arterial blood, P < .05.