| Popis: |
To investigate the mechanism of ultrasound‐enhanced fibrinolysis, the effect of ultrasound on binding of tissue plasminogen activator (t–PA) to fibrin was examined because t–PA–fibrin interactions are important in determining the rate of fibrinolysis. A novel system to quantitate t–PA–fibrin interactions was developed in which radiolabeled, active site blocked t–PA flowed through a fibrin gel at constant rate and temperature, and specific binding was determined by monitoring incorporation of radiolabel. Exposure to 1‐MHz ultrasound to 2 W cm2 resulted in no significant change in the kD of t–PA binding to either cross‐linked or noncross‐linked fibrin. Ultrasound, however, significantly increased the Bmax, and the molar binding ratio increased in the presence of ultrasound from 1.85 (mol t–PA/mol fibrin) to 2.54 (mol t–PA/mol fibrin) for noncross‐linked fibrin and from 1.19 (mol t–PA/mol fibrin) to 1.43 (mol t–PA/mol fibrin) for cross‐linked fibrin. Ultrasound resulted in no significant changes in binding o... |
