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Biomedical subjects

M F Oliver

Publications and source records attributed to M F Oliver.

At least 19 recordsLinked to original sources
PubMed1992

Cholesterol and coronary disease--outstanding questions.

The role of raised blood cholesterol in causing coronary atheroma is established, and a high dietary intake of saturated fat is a leading cause of coronary disease. Reduction of hypercholesterolemia in middle-aged males reduces CHD incidence, mostly nonfatal myocardial infarction. But there are many unresolved questions that should lead to a selective and moderate approach to the management of hypercholesterolemia. These include lack of the exact knowledge of how raised cholesterol leads to atheroma, equivocal evidence of whether reduction of hypercholesterolemia causes regression of atheroma, uncertainty about how far down cholesterol levels can safely be reduced and whether the cost-benefit always justifies action, the fact that reduction of hypercholesterolemia does not reduce total mortality and may increase noncardiac mortality, and insufficient evidence as to whether the same policies should be adopted for women, the elderly, and adolescents as for middle-aged men.

Arteriosclerosis↗
PubMed1992

Glucose tolerance, plasma insulin, HDL cholesterol and obesity: 12-year follow-up and development of coronary heart disease in Edinburgh men.

The insulin response to a standard oral glucose tolerance test (OGTT) and other anthropometric and biochemical risk factors for coronary heart disease (CHD) were measured in a random sample of 107 Edinburgh men, who were initially studied in 1976 when they were 40 and who were reexamined in 1988-89. Fasting glucose and glucose response to OGTT were higher in 1988-89 than in 1976. In contrast, insulin levels did not differ between the initial and follow-up study either before or after the glucose load. Body mass indices increased, except triceps skinfold. Changing patterns in both fasting and OGTT insulin or glucose levels in individuals were related to changes in bodyweight or in subscapular skinfolds. Modifications in serum total and HDL cholesterol were related to changes in fasting insulin and insulin area, respectively, but not to glucose data. Eleven men developed clinical CHD. Neither glucose nor insulin measures obtained in 1976 differed between those with and without CHD. Weight-height index and abdominal skin-folds were higher in those with CHD. HDL cholesterol was significantly lower (P less than 0.05). Abdominal skin-fold but not body mass index remained significant when adjusted for HDL cholesterol. This small study confirms the importance of central obesity and low HDL cholesterol but failed to identify insulin as a risk factor for CHD in this Scottish population.

Blood Glucose↗
PubMed1992

Influence of insulin resistance, secretion, and clearance on serum cholesterol, triglycerides, lipoprotein cholesterol, and blood pressure in healthy men.

Relations between serum lipids, lipoproteins, blood pressure, and insulin metabolism were investigated in 158 healthy men aged 19-77 years and with body mass indexes (BMIs) of 19-41 kg.m-2. Mathematical modeling analysis of glucose, insulin, and C-peptide concentrations during an intravenous glucose tolerance test was used to measure parameters of insulin metabolism. In univariate analysis, both fasting and postglucose insulin concentrations showed significant positive associations with fasting serum triglyceride levels (r = 0.33 and 0.38, respectively) and systolic (r = 0.22 and 0.26) and diastolic (r = 0.21 and 0.24) blood pressure and negative associations with high density lipoprotein subfraction 2 cholesterol (HDL2; r = -0.21 and -0.25). In multivariate analysis, the associations between insulin and HDL2 cholesterol concentrations were found to depend on triglyceride levels. Insulin resistance and basal pancreatic insulin secretion showed significant positive associations with serum triglycerides, which were independent of the effects of age, BMI, and fat distribution. Hepatic insulin throughout was independently associated with HDL2 cholesterol. Associations of insulin-related variables with blood pressure were generally dependent on age and BMI. These results underline the importance of insulin sensitivity and insulin concentrations as determinants of triglyceride metabolism. They also indicate a close relation between hepatic insulin handling and HDL2 concentration that is independent of triglyceride metabolism.

Adult↗
PubMed1992

Inverse relationship between serum Lp(a) levels and first-phase insulin secretion.

Relationships between serum Lp(a) levels and insulin metabolism were investigated in 147 healthy nonobese men attending an executive health-screening program. Each subject received an IVGTT with measurement of plasma levels of glucose, insulin, and C-peptide. An inverse relationship was seen with the first-phase plasma insulin response when subjects were stratified into quartile ranges of the serum Lp(a) distribution. This relationship was supported by mathematical modeling analyses of these data, which revealed an inverse relationship between serum Lp(a) levels and first-phase pancreatic insulin secretion and plasma insulin responsiveness to glucose.

Blood Glucose↗
PubMed1991

Total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol and coronary heart disease in Scotland.

OBJECTIVE: To investigate long term changes in total cholesterol, high density lipoprotein cholesterol, and low density lipoprotein cholesterol concentrations and in measures of other risk factors for coronary heart disease and to assess their importance for the development of coronary heart disease in Scottish men. DESIGN: Longitudinal study entailing follow up in 1988-9 of men investigated during a study in 1976. SETTING: Edinburgh, Scotland. SUBJECTS: 107 men from Edinburgh who had taken part in a comparative study of risk factors for heart disease with Swedish men in 1976 when aged 40. INTERVENTION: The men were invited to attend a follow up clinic in 1988-9 for measurement of cholesterol concentrations and other risk factor measurements. Eighty three attended and 24 refused to or could not attend. MAIN OUTCOME MEASURES: Changes in total cholesterol, high density lipoprotein cholesterol, and low density lipoprotein cholesterol concentrations, body weight, weight to height index, prevalence of smoking, and alcohol intake; number of coronary artery disease events. RESULTS: Mean serum total cholesterol concentration increased over the 12 years mainly due to an increase in the low density lipoprotein cholesterol fraction (from 3.53 (SD 0.09) to 4.56 (0.11) mmol/l) despite a reduction in high density lipoprotein cholesterol concentration. Body weight and weight to height index increased. Fewer men smoked more than 15 cigarettes/day in 1988-9 than in 1976. Blood pressure remained stable and fasting triglyceride concentrations did not change. The frequency of corneal arcus doubled. Alcohol consumption decreased significantly. Eleven men developed clinical coronary heart disease. High low density lipoprotein and low high density lipoprotein cholesterol concentrations in 1976, but not total cholesterol concentration, significantly predicted coronary heart disease (p = 0.05). Almost all of the men who developed coronary heart disease were smokers (91% v 53%, p less than 0.05). CONCLUSION: Over 12 years the lipid profile deteriorated significantly in this healthy cohort of young men. Smoking, a low high density lipoprotein concentration and a raised low density lipoprotein concentration were all associated with coronary heart disease in middle aged Scottish men, whereas there was no association for total cholesterol concentration. The findings have implications for screening programmes.

Adult↗
PubMed1991

Relationships of plasma viscosity, coagulation and fibrinolysis to coronary risk factors and angina.

Plasma viscosity, molecular markers of activated coagulation and fibrinolysis (fibrinopeptides A and B beta 15-42), coagulation factors (fibrinogen and factor VII) and antiplasmins were measured in 529 men aged 35-54 years and related to new angina pectoris (n = 117) and to coronary risk factors in controls without angina (n = 412). Five major risk factors (cigarette-smoking, blood pressure, cholesterol, triglyceride and body mass index) were each associated with increases in plasma viscosity, coagulation factors, and imbalance of coagulation over fibrinolysis (increased ratio of fibrinopeptide A/fibrinopeptide B beta 15-42). Increased viscosity and fibrinogen in smokers were partly reversed in ex-smokers, but the imbalance of coagulation and fibrinolysis persisted. Cholesterol and triglyceride were also associated with increased antiplasmin activity. In men with angina, only fibrinogen was elevated compared to controls. We suggest that increased plasma viscosity and an imbalance of coagulation over fibrinolysis may be mechanisms by which known risk factors promote arterial thrombosis, but are not present in stable angina.

Adult↗
PubMed1991

Risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene.

The relation between risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene was examined in a population case-control study of 110 cases of angina, identified by the Chest Pain Questionnaire, and 394 controls selected from a sample of 6000 men aged 35-54. Plasma concentrations of vitamins C and E and carotene were significantly inversely related to the risk of angina. There was no significant relation with vitamin A. Smoking was a confounding factor. The inverse relation between angina and low plasma carotene disappeared and that with plasma vitamin C was substantially reduced after adjustment for smoking. Vitamin E remained independently and inversely related to the risk of angina after adjustment for age, smoking habit, blood pressure, lipids, and relative weight. The adjusted odds ratio for angina between the lowest and highest quintiles of vitamin E concentrations was 2.68 (95% confidence interval 1.07-6.70; p = 0.02). These findings suggest that some populations with a high incidence of coronary heart disease may benefit from eating diets rich in natural antioxidants, particularly vitamin E.

Adult↗
PubMed1991

Sex difference in presynaptic adrenergic inhibition of norepinephrine release during normoxia and ischemia in the rat heart.

Using a perfused innervated rat heart model, we studied the sex difference in the sympathetic nerve stimulation-induced norepinephrine release and its presynaptic alpha 2-adrenergic inhibition in normoxic and ischemic conditions. During normoxic perfusion, the alpha 2-adrenoceptor antagonist rauwolscine resulted in a higher overflow of norepinephrine during nerve stimulation in females than in males (p less than 0.05). This more marked potentiation of norepinephrine overflow in females was accompanied by an increased chronotropic and inotropic response (p less than 0.01). During early stop-flow ischemia neural norepinephrine overflow was lower in female than in male hearts (p less than 0.005). Rauwolscine enhanced norepinephrine overflow more in females than in males (p less than 0.05), thereby eliminating the initial difference in norepinephrine overflow during ischemia between the two sexes. Ovariectomy attenuated the presynaptic alpha 2-adrenergic inhibition of norepinephrine release compared with sham-operated females (p less than 0.02). No sex difference was found in either cardiac norepinephrine content or nonexocytotic norepinephrine overflow induced by a 40-minute period of stop-flow ischemia. Thus, presynaptic alpha 2-adrenergic inhibition of myocardial norepinephrine release is greater in female than in male rats. This difference persists into the early phase of ischemia and is largely responsible for the lower neural norepinephrine release in the female heart. Female hormones may increase presynaptic alpha 2-adrenergic activity in the heart.

Adrenergic alpha-Antagonists↗