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Biomedical subjects

A S Most

Publications and source records attributed to A S Most.

82 records · Page 5Linked to original sources
PubMed1971

Muscle and splanchnic glutmine and glutamate metabolism in postabsorptive andstarved man.

Arterio-venous differences across forearm muscle in man in both prolonged starvation and in the postabsorptive state, show an uptake of glutamate and a relatively greater production of glutamine. Splanchnic arteriovenous differences in the postabsorptive state show a net uptake of glutamine and lesser rate of glutamate production. These data suggest that muscle is a major site of glutamine synthesis in man, and that the splanchnic bed is a site of its removal. The relative roles of liver and other tissues in the splanchnic circuit were not directly assessed, only the net balance. These data in man are in conflict with most previous studies in other species attributing the major proportion of glutamine production to the liver and, pari passu, to the splanchnic bed.

Abdomen↗
PubMed1969

Free fatty acid metabolism of the human heart at rest.

Myocardial substrate metabolism was studied in 13 subjects at the time of diagnostic cardiac catheterization by means of palmitic acid-(14)C infusion with arterial and coronary sinus sampling. Two subjects were considered free of cardiac pathology and all, with one exception, demonstrated lactate extraction across the portion of heart under study. Data for this single lactate-producing subject were treated separately.The fractional extraction of (14)C-labeled free fatty acids (FFA) (44.4+/-9.5%) was nearly twice that of unlabeled FFA (23.2+/-7.8%) and raised the possibility of release of FFA into the coronary sinus. FFA uptake, based on either the arterial minus coronary sinus concentration difference or the FFA-(14)C fractional extraction, was directly proportional to the arterial FFA concentration. Gas-liquid chromatography failed to demonstrate selective handling of any individual FFA by the heart. Fractional oxidation of FFA was 53.5+/-12.7%, accounting for 53.2+/-14.4% of the heart's oxygen consumption while nonlipid substrates accounted for an additional 30.0+/-17.3%. Determinations of both labeled and unlabeled triglycerides suggested utilization of this substrate by the fasting human heart. Direct measurement of FFA fractional oxidation as well as FFA uptake, exclusive of possible simultaneous FFA release, would appear necessary in studies concerned with human myocardial FFA metabolism.

Adult↗
PubMedDate not supplied

Preconditioning myocardium with demand ischemia in the presence of a critical coronary artery stenosis.

The relative importance of adrenergic stimulation and demand ischemia as important preconditioning stimuli remains unclarified. The purpose of this investigation was to use a partial coronary stenosis to define the preconditioning role of demand ischemia. Dobutamine was infused intravenously before coronary occlusion in closed-chest swine with and without an artificial coronary stenosis in the mid-left anterior descending coronary artery. Control animals had no stenosis and did not receive dobutamine before occlusion. All three groups underwent 45 minutes of occlusion followed by 120 minutes of reperfusion. At baseline, regional myocardial blood flow in the area at risk was reduced in animals with a stenosis, but global left ventricular systolic function, measured by gated blood pool scan, was equivalent in all three groups. Animals with and without a stenosis received equivalent catecholamine stress with dobutamine, but only animals with a stenosis manifested ischemia during the infusion. At 2 hours after reperfusion, infarct size as a percentage of the area at risk was smaller in animals with a stenosis given dobutamine. Demand ischemia preconditions myocardium in closed-chest swine. Increased demand alone without ischemia had marginal preconditioning effects. This may have clinical relevance to patients with severe stenoses exposed to stressful stimuli before the development of myocardial infarction.

Adrenergic beta-Agonists↗