Activation of fB in the coronary circulation after AXCL.

(a) Bb levels increased in the coronary circulation after the AXCL of human cardiac surgery. Coronary sinus blood was collected prior to AXCL and 5 minutes after AXCL termination. Bb levels were determined by ELISA using an antibody which detects the Bb component of activated fB but not native fB, nor the other fragment of fB activation, Ba. Statistical significances were analyzed as described in Materials and Methods, Section 8. Box-charts were plotted using SigmaPlot software. The boundary of the box closest to zero indicates the 25th percentile, while the boundary of the box farthest from zero indicates the 75th percentile. Error bars above and below the box indicate the 90th and 10th percentiles. The two filled circles above and below the box indicate the 95th and 5th percentiles. The solid line within the box marks the median, and the dotted line marks the mean (average). N = 56; * indicates statistical significance (P < 0.05). (b) Plasma from the coronary sinus blood obtained before the start of AXCL and 5 minutes after AXCL cessation was analyzed by Western blotting using a polyclonal antibody that detects fB and Bb. A representative blot is depicted showing fB positive bands from a patient’s plasma. Arrows indicate fB and Bb fragments. Band intensities on scanned images of such blots were quantified and normalized to the 93 kDa fB band of a control plasma and expressed as relative intensity. (c) A bar chart summarizes the relative intensities of Bb fragments.