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Biomedical subjects

M F Oliver

Publications and source records attributed to M F Oliver.

At least 181 records · Page 10Linked to original sources
PubMed1976

Effects of dichloroacetate on myocardial substrate extraction, epicardial ST-segment elevation, and ventricular blood flow following coronary occlusion in dogs.

Glucose metabolism in the healthy heart is stimulated by dichloroacetate (DCA). The possibility has been examined in dogs that DCA, by increasing glucose utilization, might limit the severity of acute myocardial ischaemic injury. Intravenous administration of DCA reduced the degree of epicardial ST-segment elevation induced by subsequent coronary occlusion, both under basal conditions and during isoprenaline infusion. A similar result was obtained when DCA was given during an established coronary occlusion. This effect could not be explained by changes in mean aortic blood pressure, heart rate, or regional myocardial blood flow as measured by radioactive microspheres. Measurements in arterial and coronary sinus blood demonstrated an increase in the extraction of glucose and a decrease in that of FFA by the heart. Glucose extraction also tended to be increased in the ischaemic zone, as shown by the differences in the concentrations of these substrates between arterial blood and blood obtained from the local vein draining that zone. Lactate release by the ischaemic zone was markedly reduced.

Acetates↗
PubMed1976

The effect of antilipolytic agents on cyclic AMP, free fatty acid and total catecholamine concentrations in plasma.

Plasma concentrations of adenosine 3':5' cyclic monophosphate (cyclic AMP) and free fatty acids have been measured in 15 patients with acute myocardial infarction and in 6 dogs given infusions of isoprenaline. Plasma total catecholamines were also estimated in the patients. Inhibition of adipose tissue lipolysis with a nicotinic acid analogue did not decrease plasma cyclic AMP concentrations, either in the patients or when elevated in the dogs, thus suggesting that this tissue is not a major source of the nucleotide in plasma.

Acute Disease↗
PubMed1976

Antilipolytic therapy in angina pectoris. Reduction of exercise-induced ST segment depression.

A double-blind cross-over study was performed on 12 men sith stable angina pectoris in order to determine the effect of antilipolytic treatment on exercise tolerance and exercise-induced electrocardiographic changes. The men were exercised to the onset of anginal pain using a reproducible and standardized ergometric load. A nicotinic acid analogue was used to reduce plasma free fatty acids and free glycerol before and during exercise testing and to eliminate their post-exercise rise. This was associated with significant reduction of exercise-induced ST segment depression (p less than 0-005), though there was no significant difference in the duration of exercise before the oneset of pain. A change in the prportions of lipid and carbohydrate for oxidation by the ischaemic myocardium, making relatively more glucose available, is a likely explanation.

Aged↗
PubMed1976

Creatine kinase MB isoenzyme studies in diagnosis of myocardial infarction.

Serial measurements of the MB isoenzyme of creatine kinase, total creatine kinase, aspartate mainotransferase, and urea stable lactate dehydrogenase have been made in the serum of a series of 139 patients admitted with a diagnosis of suspected myocardial infarction. Serum MB isoenzyme measurements have also been made on postoperative surgical patients and patients with medical disorders known to have caused raised serum total creatine kinase activity. All these enzymes were abnormal in at least one specimen from all patients with electrocardiographically proved acute myocardial infarction. The magnitude of the MB isoenzyme rise was 2 to 3 times greater than that of any of the other enzymes. The duration of its rise was relatively short. The MB isoenzyme was more specific for myocardial infarction than other enzymes and no increases were found in postoperative patients, except in those after cardiac bypass surgery. The MB isoenzyme seems the most sensitive and specific test for myocardial infarction available, though there are technical problems in its accurate measurement.

Adult↗
PubMed1976

Effects of p-chlorophenoxyisobutyrate on myocardial free fatty acid extraction, ventricular blood flow, and epicardial ST-segment elevation during coronary occlusion in dogs.

The effect of p-chlorophenoxyisobutyrate (CPIB) on ST-segment elevation in epicardial electrocardiographic recordings was studied during coronary artery occlusion in dogs. Occlusion alone raised the sum of ST-segment elevations (sigmaST) to 26 +/- 6 mV (mean +/- SEM). Intravenous (i.v.) administration of CPIB 30 min before re-occlusion reduced sigmaST to 14 +/- 3 mV (P less than 0.03). A continuous i.v. infusion of isoproterenol increased sigmaST to 74 +/- 11 mV. Pretreatment with CPIB reduced sigmaST during isoproterenol infusion to 40 +/- 7 mV (P less than 0.005). CPIB had no effect on mean aortic blood pressure, heart rate, or regional myocardial blood flow, as measured by radioactive microspheres. Arterial free fatty acid (FFA) concentrations were reduced by CPIB from 466 +/- 41 to 221 +/- 44 muEq/L (P less than 0.001) in the basal state, and from 1966 +/- 183 to 1429 +/- 209 muEq/L (P less than 0.001) during isoproterenol infusion. The reduction in arterial FFA concentration was associated with a proportionate decrease in the myocardial extraction of FFA. Similar changes were observed when CPIB was administered during an occlusion which had been established 10 min earlier. These observations support other evidence that the severity of acute myocardial ischemic injury in dogs is positively correlated with the myocardial extraction of FFA, and that the severity of the ischemic injury can be reduced by effective antilipolytic therapy.

Animals↗
PubMed1976

Significance of ventricular arrhythmias during myocardial ischemia.

The scoring of premature ventricular contractions (PVC) after myocardial infarction provides little accurate information about infarct size or about other ventricular arrhythmias, although it might be of some immediate prognostic value. Continuous recording with computer analysis and differentiation of serious ventricular arrhythmias has shown in untreated patients that the incidence of PVC does not reflect that of other ventricular arrhythmias. Ventricular tachycardia and R-on-apex T PVC continue without significant decrease in incidence up to 12 hours after the onset of symptoms. Primary ventricular fibrillation is rare after about 5 hours and stands on its own in significance.

Arrhythmias, Cardiac↗