A rapid method for the preparation of stable 99Tcsup(m)-urokinase

Urokinase, which is a fibrinolytic enzyme extracted from the urine, has important advantages over the available routine techniques for detecting deep vein thrombosis in clinical practice. A description is given of a simple and reliable electrolytic method for labelling urokinase with 99Tcsup(m). The procedure gave a high yield of stable, labelled enzyme. In vitro uptake by coagulated human blood ranged from 61.8 to 66% after 15 min. Acute toxicity, blood clearance and organ distribution were studied in rats. The results confirmed the potential of this compound for the rapid detection of formed or forming deep vein thrombi, and indicated that it may also be useful in detecting pulmonary emboli. (U.K.)