Abstract | OBJECTIVE: METHODS: Thirty-two newborn piglets underwent thoracotomy and placement of a pulmonary artery-to-left atrium shunt or sham operation. Two weeks later, partial pressure of arterial oxygen, hematocrit, and left ventricular shortening fraction values were compared with baseline values. Northern blot hybridization and protein immunoblotting for ventricular cytochrome oxidase subunit I were performed. Cytochrome oxidase kinetic activity was measured. Heme a,a3 content and turnover number were determined. Significance was assessed with a t test. RESULTS: Baseline partial pressure of arterial oxygen and hematocrit values were similar. Hypoxemic piglets had a lower partial pressure of arterial oxygen of 38 +/- 10 mm Hg (P < .001) and higher hematocrit value of 31.4% +/- 2.9% (P < .001) compared with a partial pressure of arterial oxygen of 140 +/- 47 mm Hg and hematocrit value of 24.6% +/- 3.9% after the sham operation. Baseline and postprocedure left ventricular shortening fraction were similar within and between groups. Chronic hypoxemia increased right ventricular and left ventricular cytochrome oxidase I mRNA and protein by more than 1.4-fold. Cytochrome oxidase activity increased significantly in hypoxemia by 2.5-fold compared with that seen after the sham operation. Heme a,a3 content and turnover number increased by 1.5-fold during hypoxemia. CONCLUSIONS: Chronic hypoxemia increases cytochrome oxidase I message, protein expression, and activity. The increase in kinetics was due to increased enzyme content and catalytic activity. This is a possible adaptive mechanism that might preserve organ function during chronic hypoxemia.
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Authors | David A Piel, Azeem R Khan, Robert Waibel, Mariusz Birbach, Meryl S Cohen, Thomas L Spray, Clifford S Deutschman, J William Gaynor, Richard J Levy |
Journal | The Journal of thoracic and cardiovascular surgery
(J Thorac Cardiovasc Surg)
Vol. 130
Issue 4
Pg. 1101-6
(Oct 2005)
ISSN: 1097-685X [Electronic] United States |
PMID | 16214526
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Electron Transport Complex IV
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Topics |
- Animals
- Animals, Newborn
- Chronic Disease
- Electron Transport Complex IV
(metabolism)
- Hypoxia
(enzymology)
- Myocardium
(enzymology)
- Swine
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