Release of PAI from the vessel wall.

PAI-1 antigen levels in plasma 40 minutes after a 3-minute carotid artery photochemical injury, compared with control values (rose-bengal injection without injury); effect of ligation without injury (second bar) and of ligation in combination with injury (fourth bar) on PAI-1 plasma concentrations is also shown. Data are mean ± SEM for the number of animals indicated between parenthesis. *P < .01 by Dunn's multiple comparison test in comparison with the groups indicated by the horizontal brackets; †P < .05; ‡P < .05 by alternative t test for the direct comparison between the groups indicated; these groups had unequal SD distribution.