Uehara A, Isaka Y, Etani H, Kimura K, Yoneda S, Kamada T, Kozuka T, Nobuhara M
Division of Nuclear Medicine, Osaka University Medical School, Japan.
Nuklearmedizin. 1987 Oct;26(5):224-8.
Tissue-type plasminogen activator (t-PA) which has a high affinity for fibrin in the clot, was labeled with 131I by the iodogen method, and its binding to de-endothelialized lesions in the rabbit was measured to assess the detectability of thrombi. The de-endothelialized lesion was induced in the abdominal aorta with a Fogarty 4F balloon catheter. Two hours after the de-endothelialization, 131I-labeled t-PA (125 +/- 46 microCi) was injected intravenously. The initial half-life of the agent in blood (n = 12) was 2.9 +/- 0.4 min. The degree of binding of 131I-labeled t-PA to the de-endothelialized lesion was evaluated at 15 min (n = 6) or at 30 min (n = 6) after injection of the agent. In spite of the retention of the biochemical properties of 131I-labeled t-PA and the presence of fibrin deposition at the de-endothelialized lesion, the binding of t-PA to the lesion was not sufficiently strong. Lesion-to-control ratios (cpm/g/cpm/g) were 1.65 +/- 0.40 (at 15 min) and 1.39 +/- 1.31 (at 30 min), and lesion-to-blood ratios were 1.39 +/- 0.32 (at 15 min) and 1.36 +/- 0.23 (at 30 min). These results suggest that radiolabeled t-PA may be inappropriate as a radiopharmaceutical for the scintigraphic detection of a pre-existing thrombotic lesion.
组织型纤溶酶原激活剂（t-PA）对凝块中的纤维蛋白具有高亲和力，采用碘珠法用131I对其进行标记，并测量其与兔去内皮病变的结合情况，以评估血栓的可检测性。用Fogarty 4F球囊导管在兔腹主动脉诱导去内皮病变。去内皮2小时后，静脉注射131I标记的t-PA（125±46微居里）。该制剂在血液中的初始半衰期（n = 12）为2.9±0.4分钟。在注射该制剂后15分钟（n = 6）或30分钟（n = 6）评估131I标记的t-PA与去内皮病变的结合程度。尽管131I标记的t-PA保留了生化特性，且去内皮病变处有纤维蛋白沉积，但t-PA与病变的结合不够强。病变与对照的比值（每分钟计数/克/每分钟计数/克）在15分钟时为1.65±0.40，在30分钟时为1.39±1.31，病变与血液的比值在15分钟时为1.39±0.32，在30分钟时为1.36±0.23。这些结果表明，放射性标记的t-PA作为一种放射性药物用于对已存在的血栓病变进行闪烁显像检测可能不合适。
