الفهرس 
Introduction and the Aim of WorkOnly 14 pages are availabe for public view
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Abstract
: Ischemic heart disease cause more deaths and disability and incurs great economic costs. The endothelium has been recognized as an extremely active source of vasoactive substances, one such is endothelin1 (ET1). Endothelin1 is one of three isoforms of endothelins in human, namely ET1, ET2 and ET3. It interacts with 2 distinct receptor subtypes; ETA and ETB endothelin receptors to exert its biologic actions. Besides modulating peripheral and coronary vascular tone, ET1 evokes several biological effects, including stimulation of smooth muscle cell growth and inflammatory responses, that may be implicated in the pathogenesis of coronary atherosclerosis. The role of ET1 in the pathogenesis of ischemic heart diseases has been paid much attention during the last years, however, the reported results are controversial. Aim: The controversy about the circulating ET1 concentrations in patients suffering from angina pectoris, either stable or unstable, encouraged us to determine plasma ET1 concentrations in these patients. Subjects & Methods: The present study was conducted on the following groups: I) 13 apparently healthy individuals (10 males and 3 females) of ages ranging between 37 and 65 years (median (R+ (BSIR = 47.00 (R+ (B6.25) were studied as a reference (control) group <U+F05B>A<U+F05D>. II) 69 subjects suffering from ischemic heart disease (54 males and 15 females) of ages ranging between 40 and 65 years (median (R+ (BSIR = 50.00 (R+ (B4.75). Patients were classified according to clinical data and investigations into the following groups; group <U+F05B>B<U+F05D>: 10 males with stable angina pectoris, <U+F05B>C<U+F05D>: 34 patients with unstable angina pectoris (25 males and 9 females), <U+F05B>D<U+F05D>: 12 patients with acute myocardial infarction (9 males and 3 females), and group <U+F05B>E<U+F05D>: 13 patients with postmyocardial infarction unstable angina pectoris (10 males and 3 females). Samples were taken from them under certain precautions and assayed for plasma endothelin1 concentrations by Enzyme Immunometric Assay (EIA) kit. Results: In this study, a significant increase in plasma ET1 concentrations was found in acute myocardial infarction, unstable angina and in post myocardial infarction unstable angina groups when compared with the control group (P= 0.002, 0.001, 0.007 respectively). On the other hand, there was no significant increase in plasma ET1 concentration in stable angina pectoris group compared with that of healthy control value (P= 0.38). Comparing plasma ET1 concentrations in the different IHD groups in the present work, there was not significant differences in plasma ET1 concentrations values. However, the percentage of the increase in plasma ET1 concentrations in the different IHD groups compared with the control group was the highest in patients with in post myocardial infarction unstable angina (74.42 %), followed by that in patients with acute myocardial infarction (68.84 %), then patients with unstable angina (65.58 %) and lastly patients with stable angina (29.30 %). In this study, results of multiple linear regression analysis of ET1 with other variables in post myocardial infarction unstable angina group showed that LDLC is significantly affects ET1 (P= 0.012). Conclusions : <U+2022> Stable angina pectoris is not always associated with elevated plasma ET1 concentrations (short & incomplete vasoconstriction). <U+2022> Unstable angina pectoris (either primary or post myocardial infarction), is always associated with an increase in plasma ET1 concentrations during the acute phase. <U+2022> Acute myocardial infarction is always associated also with an increase in plasma ET1 concentrations. <U+2022> There is a positive relation between plasma ET1 levels and the development of acute coronary syndromes (Unstable angina pectoris & Acute myocardial infarction). <U+2022> There is no difference in plasma ET1 level between Unstable angina pectoris & Acute myocardial infarction. <U+2022> Plasma ET1 levels are related to coronary vasoconstriction rather than myocardial damage. Recommendations : <U+2022> Further intense researches focusing on multiple vascular endothelial vasoactive mediators should be carried out, in hope of clarifying their interrelations in coronary atherogenesis