46 research outputs found

    Myocardial salvage with trolox and ascorbic acid for an acute evolving infarction

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    Both Trolox (a water-soluble analogue of \u3b1-tocopherol) and ascorbic acid were more effective than superoxide dismutase or catalase in protecting myocyte cell cultures from free radical attack (induced by hypoxanthine and xanthine oxidase). In a canine model of two hours of left anterior descending coronary artery occlusion followed by four hours of reperfusion, Trolox and ascorbic acid reduced the area of infarction within the area at risk. The Trolox group received 500 mL of deoxygenated saline solution containing 2.0 g of Trolox, 3.0 g of ascorbic acid, and 18 mg of EDTA (ethylenediaminetetraacetic acid) infused into the ascending aorta 30 seconds before and four minutes after reperfusion. Saline controls received 500 mL of deoxygenated saline solution containing 18 mg of EDTA. The angioplasty group had unmodified reperfusion by simple release of the occlusion. The area at risk and the area infarcted were estimated with Evans blue and triphgnyl tetrazolium hydiochloride stains, respectively. The ratio of the area infarcted to the area at risk was significantly lower with Trolox (angioplasty, 33.4% \ub1 5.1%; saline, 20.8% \ub1 2.9%; and Trolox, 8.7% \ub1 4.0%; p < 0.01). In summary, the antioxidants Trolox and ascorbic acid effectively reduced myocardial necrosis after ischemia. \ua9 1989.Peer reviewed: YesNRC publication: Ye

    Myocardial free-radical injury after cardioplegia

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    Although cold blood cardioplegia provides excellent myocardial protection for elective coronary bypass surgery, myocardial metabolic recovery is delayed postoperatively, perhaps because of free-radical injury during reperfusion. To assess free-radical reperfusion injury, we measured the products of lipid peroxidation and the cardiac concentrations of alpha tocopherol in 10 patients undergoing elective surgical revascularization. Arterial and coronary sinus blood measurements revealed a delayed recovery of myocardial oxygen consumption and lactate utilization and the myocardial release of conjugated dienes (chemical signatures of free-radical injury) at 3 and 60 minutes after reperfusion. In addition, myocardial concentrations of alpha tocopherol decreased after reperfusion, suggesting consumption of the major membrane antioxidant. These results support the hypothesis that oxygen-derived free radicals contribute to myocardial injury after cardioplegic arrest and that antioxidant therapy should improve myocardial protection.Peer reviewed: YesNRC publication: Ye
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