Intestinal vessel thrombosis during hirudin treatment. Distribution of occlusion time and mean (horizontal bars) upon injury induction in venules (top panel) and arterioles (bottom panel) of WT or Tsp1-null hirudin-treated mice, for the indicated number of mice (m), in control conditions (C), and after treatment with human TSP-1, either with a bolus of 240 μg/kg + infusion of 240 μg/kg/h or 2400 μg/kg + infusion of 2400 μg/kg/h; P values were calculated via nonparametric Mann-Whitney test, with 2-tailed P value.