In situ detection of EGF receptor mRNA in human atheromatous lesions: Implications for proliferation and migration of smooth muscle cells S. Urn Judith b. Swain, and Rkhara S. Stack. has potential introduced into coronary ipheral arteries in vivo, with resultant expression of gene s. In addition, we show that a percutaneous catheter approach can be used for localized gene transfer into coronary arteries. This method offers an interventional approach to the treatment of cardiovascular disease through gene therapy. FIBRINOL’6TIC AGTIV1T-Y FOUQWXMG VASCUQR WALL INJURY Ui Shi, Andrew Zalewski, Donald Nardone, Paul Walinsky, Thorir D. Bjornsson, Thomas Jefferson University, Philadelphia, PA Vessel wall injury in either acute coronary smdromes or during coronary angiaplasty is associated with increased procoagulant activity and frequent intracoronary thrombi. Accordingly, the aim of this study was to assess plasma levels of tissue plasminogen activator activity (t-PA) and piasminogen activator inhibitor-l activity (PM-P) prior to and at i, 6, and 24 hr after experimental vessel wall injury (INS). In 26 atherosclerotic rabbits, IN9 was produced by angioplasty of iliac arteries IPL 18, while 8 rabbits with no 1N.l seared as controls (C). Histology in 9 rabbits from INJ group revealed medial INJ in all enimals. t-PA levels Baseline 1 hr 6 hr 24 hr C 13.53k2.07 11.97+1.81 14.16+0.99 12.6721.32 INJ 14.89+1.02 13.5720.87 14.7320.86 16.64+1.05 t-PA levels were not different between C and INJ groups. AI-l levels (AU/ml, mean -+ SEM) were as follows: Baseline 1 hr 6 hr 24 hr C 21.%0+1.34 22.7252.50 21.6623.57 22.2822.67 INJ 21.7911.27 22.61k1.11 32.05&1.47+ 23.99k1.16 Thus. PAI- activity increased significantly at 6 hr followitlg INJ (*QiO.Ol vs INJ at baseline, 1, 24 hr and vs all times in C group). In contrast, C group showed n, change throughout the study period. Conclusions: 1) Fibrinolytic activity was transiently impaired following deep vascular wall injury as a result of an increase in PAI- activity. 2) In addition to other procoagulant mechanisms, PAX-1 elevation in the presence of vessel wall injury may play a role in the pathogenesis of acute coronary syndromes. THE EFFECT OF TPA Gh RESTEtiL?SIS FOLL’JWINC EALLOOE AXIOPLASTY: A STUDY IN THE ATHEROSCLEROTIC RABBIT. -lo