Urokinase administration and hypercoagulability

Abstract

The thrombolytic treatments for peripheral vascular thrombosis have been reported. In these clinical trials of urokinase treatment, hypercoagulability after urokinase administration has been experienced.
It was studied that any amounts of urokinase are responsible for the activation of partial thromboplastin time (PTT).
Influences on PTT after U K administration were in vitro investigated with the recorder, EEL, aggregometer Model 169.
Various concentrations of urokinose were added into plasma and incubated for 15min at 37°C. Shortening of PTT was identified over the range of 0.075-1.25 i. u./ml of UK concentration. But UK more than 1.25 i. u./ml had no effect for the activation of PTT.
The PTT of exhausted and fresh plasma equally mixed preparation, was shorten by the addition of same amounts of UK mentioned above.
It was suggested that low concentration of UK might have the effect of activating contact factor, and dextran sulfate do the similar effect as UK.
Low doses of heparin (0.4r/m1-1.7r/ml) inhibited the activation of PTT by UK, and combined use of LMD with UK prolonged PTT.
It was concluded that the administration of LMD and heparin with UK is reasonable and desirable for antithrombotic treatment.
The real mechanism why low amounts of UK have the activity of shortening PTT and enhances the contact factor activity, remains unknown and under investigation.