Document Detail


Performance of the neonatal pig heart subjected to oxygen insufficiency.
MedLine Citation:
PMID:  14631166     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Isolated, paced, isovolumically beating, neonatal pig (n = 32) hearts underwent retrograde aortic perfusion with a solution containing insulin (100 microU/ml), glucose (5.5 mM), and palmitate (0.55 mM). Glycolysis, lactate release, glucose oxidation, palmitate oxidation, and oxygen consumption were assessed. The hearts were perfused during three periods: (1) baseline, pO(2) approximately 500 mm Hg, heart rate 150 bpm; (2) hypoxia, pO(2) approximately 60-80 mm Hg, heart rate 150 bpm, or tachycardia, pO(2) approximately 500 mm Hg, heart rate 300 bpm, and (3) recovery, return to baseline conditions. For hypoxia and tachycardia, the oxygen supply-demand ratio was comparable ( approximately 1 nmol O(2)/mm Hg/g(dry)). During baseline, the left ventricular peak systolic pressure (PSP) averaged 126 +/- 6 mm Hg, the end-diastolic pressure (EDP) 5 mm Hg, and the relaxation time constant (Tau) 34 +/- 2 ms; the coronary flow was 36 +/- 2 ml/min/g(dry). During hypoxia, the PSP decreased to 70 +/- 2 mm Hg, while EDP, Tau, and coronary flow increased to 26 +/- 2 mm Hg, 104 +/- 14 ms, and 70 +/- 2 ml/min/g(dry), respectively; palmitate oxidation and oxygen consumption decreased well below baseline. During tachycardia, the PSP decreased to 88 +/- 1 mm Hg, and the EDP increased to 11 +/- 1 mm Hg, while Tau and coronary flow did not change significantly; palmitate oxidation and oxygen consumption increased above baseline. For both stressors, the predicted lactate release underestimated the measured values by a factor of approximately 2, but were comparable during baseline and recovery. Upon recovery, PSP returned to approximately 80% of baseline, while EDP remained elevated, for both stressors. Glucose oxidation returned to baseline, but palmitate oxidation became accelerated. We conclude for neonatal pig hearts subjected to oxygen insufficiency: (1) that PSP decreases and (2) that EDP and Tau increase with hypoxia, whereas EDP increases, while Tau remains unchanged with tachycardia. Following both stressors, palmitate oxidation becomes enhanced and dissociated from mechanical activity.
Authors:
Rowena Uy; Nikola Tede; Nancy Ross-Ascuitto; Robert Ascuitto
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't     Date:  2003-11-19
Journal Detail:
Title:  Biology of the neonate     Volume:  85     ISSN:  0006-3126     ISO Abbreviation:  Biol. Neonate     Publication Date:  2004  
Date Detail:
Created Date:  2004-03-12     Completed Date:  2004-10-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0247551     Medline TA:  Biol Neonate     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  42-50     Citation Subset:  IM    
Copyright Information:
Copyright 2004 S. Karger AG, Basel
Affiliation:
Section of Cardiology, Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn / physiology*
Anoxia
Aorta
Blood Pressure
Coronary Circulation
Diastole
Glucose / administration & dosage,  metabolism
Glycolysis
Heart / physiology*
Heart Rate
Insulin / administration & dosage
Lactic Acid / metabolism
Oxidation-Reduction
Oxygen / administration & dosage*
Oxygen Consumption
Palmitic Acid / administration & dosage,  metabolism
Perfusion
Solutions
Swine
Systole
Chemical
Reg. No./Substance:
0/Solutions; 11061-68-0/Insulin; 50-21-5/Lactic Acid; 50-99-7/Glucose; 57-10-3/Palmitic Acid; 7782-44-7/Oxygen

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