| Effects of exogenous oxygen derived free radicals on myocardial capillary permeability, vascular tone, and incidence of ventricular arrhythmias in the canine heart. | |
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MedLine Citation:
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PMID: 1288864 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVE: The aim was to examine the effects of exogenous oxygen derived free radicals on myocardial capillary permeability for a small hydrophilic indicator, postischaemic vascular tone, and the occurrence of arrhythmias in the canine heart in vivo. METHODS: Free radicals were generated by simultaneous intracoronary infusion of hypoxanthine and xanthine oxidase into normally perfused myocardium, and at reperfusion following five minutes of coronary occlusion, respectively, in 20 anaesthetised open chest dogs. Myocardial capillary extraction for 99mTc-DTPA, plasma flow rate, and the interstitial washout rate constant were measured by the single injection, residue detection method, and the capillary permeability-surface area product (PS) was calculated. The maximum plasma flow during reactive hyperaemia was measured by the local 133Xe washout method. RESULTS: Hypoxanthine and xanthine oxidase infusion into normally perfused myocardium induced a 15% decrease in capillary extraction (p = 0.05), a 24% decrease in PS (p < 0.01), and a 23% decrease in the interstitial washout rate constant (NS) two minutes after the end of the infusion. When hypoxanthine and xanthine oxidase were infused into postischaemic myocardium, 86% of animals developed sustained ventricular arrhythmias, in contrast to none in control experiments (p < 0.05). The maximum plasma flow was 363% of preocclusive values in control experiments v 268% in hypoxanthine + xanthine oxidase experiments (p < 0.05). CONCLUSIONS: In normally perfused hearts, intracoronary infusion of hypoxanthine and xanthine oxidase induce a decreased capillary extraction, suggesting a reduced capillary surface area. In postischaemic myocardium these substances cause a decreased vasodilatation in the initial phase of reactive hyperaemia, and induce ventricular arrhythmias. |
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Authors:
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J H Svendsen; P J Bjerrum |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Cardiovascular research Volume: 26 ISSN: 0008-6363 ISO Abbreviation: Cardiovasc. Res. Publication Date: 1992 Dec |
Date Detail:
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Created Date: 1993-03-22 Completed Date: 1993-03-22 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0077427 Medline TA: Cardiovasc Res Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 1181-8 Citation Subset: IM |
Affiliation:
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Rigshospitalet, University of Copenhagen, Denmark. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arrhythmias, Cardiac / etiology* Capillary Permeability / drug effects, physiology* Dogs Female Hypoxanthines / pharmacology Male Myocardial Reperfusion Injury / complications, metabolism* Myocardium / metabolism* Reactive Oxygen Species / metabolism* Vascular Resistance / drug effects, physiology* Xanthine Oxidase / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Hypoxanthines; 0/Reactive Oxygen Species; EC 1.17.3.2/Xanthine Oxidase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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