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Biomedical subjects

A Coulston

Publications and source records attributed to A Coulston.

12 recordsLinked to original sources
PubMed2001

Insulin resistance, dietary cholesterol, and cholesterol concentration in postmenopausal women.

Questions remain concerning the effect of variations in cholesterol intake on plasma cholesterol concentration, as well as on the role of factors modulating the metabolic impact of this dietary intervention. To define the impact of wide variations in dietary cholesterol intake on plasma total and low-density lipoprotein (LDL) cholesterol concentrations, as well as testing the hypothesis that resistance to insulin-mediated glucose disposal would accentuate the increase in plasma total and LDL cholesterol concentrations in response to a given increment in dietary cholesterol intake, we performed a prospective, randomized study comparing diets varying in cholesterol content in 65 healthy, postmenopausal women, 31 defined as insulin-resistant and 34 as insulin-sensitive. The changes in total and LDL cholesterol in response to increments in dietary cholesterol of up to approximately 800 mg/day were modest in magnitude, without evidence of a statistically significant diet-induced increase in cholesterol concentration, or of any difference in the responses of insulin-resistant as compared with insulin-sensitive women. These results indicate that relatively large increments in dietary cholesterol intake had little effect on total or LDL cholesterol concentrations in healthy, postmenopausal women, irrespective of whether they were insulin-resistant or insulin-sensitive.

Apolipoproteins A↗
PubMed1995

Postprandial triglyceride and retinyl ester responses to oral fat: effects of fructose.

It has been shown that addition of fructose to an oral fat load results in higher postprandial concentrations of triglyceride. The present study, performed in 11 healthy volunteers, was initiated to see whether the effect of fructose on fat-induced lipemia also involved changes in postprandial concentrations of triglyceride-rich lipoproteins of intestinal origin. Vitamin A was used to label intestinal lipoproteins, and the retinyl palmitate concentrations were determined in plasma and in the Sf > 400 and Sf 20-400 lipoprotein fractions (Sf denotes the Svedberg flotation index). Addition of fructose (50 g) to a standard (40-g oral) fat load resulted in higher postprandial concentrations of triglyceride and retinyl palmitate in plasma and the Sf > 400 lipoprotein fraction (P < 0.001, analysis of variance), and the higher the fasting plasma triglyceride concentration, the greater the magnitude of the fructose effect (r = 0.83, P < 0.002). These data show that triglyceride-rich lipoproteins of intestinal origin play a role in the fructose-induced accentuation of postprandial lipemia.

Administration, Oral↗
PubMed1993

Differences in postprandial lipemia between patients with normal glucose tolerance and noninsulin-dependent diabetes mellitus.

In this paper we have compared the postprandial increase in triglyceride (TG) rich lipoproteins of intestinal origin in 10 patients with noninsulin-dependent diabetes mellitus (NIDDM) and 10 subjects with normal glucose tolerance. The two groups were matched for age, sex distribution, body mass index, and plasma TG concentration. Breakfast was consumed at 0800 h and lunch at 1200 h, at which time vitamin A was also administered. Blood was sampled frequently from 1200 h to 2400 h, and measurements made of glucose, insulin, and TG concentrations. Furthermore, the retinyl palmitate (RP) content of plasma, the Sf > 400 lipoprotein fraction, and the Sf 20-400 lipoprotein fraction was also determined, and differences compared by two-way analysis of variance. Fasting and postprandial (from 1200 h to 2400 h) TG concentrations in the plasma and the two lipoprotein fractions were not significantly different in normal subjects and patients with NIDDM. In addition, the postprandial RP concentration of the two groups was not different in the chylomicron containing Sf > 400 lipoprotein fraction. However, the postprandial Sf 20-400 RP concentration was significantly higher (P < 0.001) in patients with NIDDM, estimated as hourly values over time, peak value, or total integrated response area. Significant correlation coefficients (r = 0.60-0.75, P < 0.08 < 0.02) were seen in patients with NIDDM between the total integrated insulin response and both the TG and RP responses in the Sf > 400 and Sf 20-400 fractions. In addition, fasting high density lipoprotein-cholesterol concentration in patients with NIDDM was significantly correlated with the postprandial TG response in the Sf > 400 (r = -0.64, P < 0.05) and the Sf 20-400 (r = -0.68, P < 0.05) lipoprotein fractions. In summary, the postprandial RP concentration in the Sf 20-400 lipoprotein fraction was higher than normal in patients with NIDDM. In addition, associations have been defined in patients with NIDDM between postprandial insulin response, fasting TG and high density lipoprotein-cholesterol concentrations, and magnitude of postprandial increase in TG-rich lipoproteins of intestinal origin.

Blood Glucose↗
PubMed1988

Effect of a low fat diet on carbohydrate metabolism in patients with hypertension.

Plasma glucose and insulin responses to both a 75-g oral glucose challenge and to conventional meals were determined in eight patients with hypertension and compared with values of a control population. The results indicated that patients with hypertension had significantly higher than normal plasma glucose and insulin concentrations in both situations. Furthermore, when dietary carbohydrate was increased by 16% of total calories (with a reciprocal reduction in dietary fat), the hyperglycemia and hyperinsulinemia present in patients with hypertension were accentuated. Since low fat-high carbohydrate diets are usually recommended for patients with hypertension, these data suggest that abnormalities of glucose and insulin metabolism associated with hypertension would be increased if patients with high blood pressure followed conventional dietary advice. Since hyperglycemia and hyperinsulinemia have been shown to be associated with an increased risk of developing coronary artery disease, it may be appropriate to reevaluate the clinical utility of low fat-high carbohydrate diets in the treatment of hypertension.

Blood Glucose↗
PubMed1984

The effect of sucrose content in high and low carbohydrate diets on plasma glucose, insulin, and lipid responses in hypertriglyceridemic humans.

To further understand the effect of high carbohydrate (CHO)-low fat diets and the role of variations in dietary sucrose on CHO and lipid metabolism, 10 patients with hypertriglyceridemia were fed 2 isocaloric, typical American diets, containing 40% and 60% CHO, for 15 days in random sequence. Each patient was their own control, and they were divided into 2 groups of 5 patients each. In one group, sucrose was held constant at 13% of total calories (40-13% and 60-13%), whereas the sucrose content was 9% of the total calories on a 40% CHO diet (40-9%), and 15% of total calories on a 60% CHO diet (60-15%) in the other group. Fasting and postprandial blood samples were analyzed for plasma glucose, insulin, cholesterol (Chol), and triglycerides (TG), as well as for Chol and TG in chylomicrons, very low density, low density, and high density lipoproteins (HDL). Fasting plasma TG levels were significantly increased in both groups on the 60% CHO diet, primarily due to increases in very low density-TG concentration. The magnitude of the elevation was attenuated when sucrose content was kept constant. Postprandial TG responses were qualitatively similar. There were no significant changes in plasma Chol concentrations, except for a modest fall in plasma HDL-Chol level after the 60-13% diet period (P less than 0.05). No significant differences were found in fasting plasma glucose or insulin concentration. However, postprandial glucose and insulin responses were increased on both high CHO diets. The results of these studies demonstrate that high CHO-low fat diets, in general, tend to elevate plasma glucose, insulin, and TG concentrations and reduce HDL-Chol concentration in patients with endogenous hypertriglyceridemia. In addition, these data illustrate the important role that small variations in dietary sucrose can play in modulation of CHO and lipid metabolism.

Blood Glucose↗
PubMed1983

Does day-long absolute hypoinsulinemia characterize the patient with non-insulin-dependent diabetes mellitus?

Plasma glucose and insulin responses to a standard oral glucose tolerance test (75 g of glucose) and to mixed meals were compared in 15 normal subjects and 15 patients with non-insulin-dependent diabetes mellitus (NIDDM). Fasting plasma glucose levels were above 140 mg/dL in all patients with NIDDM, and the two groups were weight matched. Plasma glucose levels were significantly higher in patients with NIDDM throughout the glucose tolerance test, and this was associated with a marked reduction in plasma insulin response. Plasma glucose levels were also higher in patients with NIDDM when measured hourly from 8 AM to 5 PM (mixed meals were consumed at 8 AM and 12 PM), but the plasma insulin concentration of the two groups were similar. Thus, the day-long circulating insulin levels of patients with NIDDM are not reduced. Consequently, these patients cannot be considered to be absolutely insulin deficient.

Adult↗
PubMed1981

Effect of differences in source of dietary carbohydrate on plasma glucose and insulin responses to meals in patients with impaired carbohydrate tolerance.

Two test meals, varying only in type of carbohydrate foods, were given to 12 volunteers with impaired glucose tolerance. The carbohydrate content of one meal was composed of potato and gelatin, while the other meals contained an equivalent amount of carbohydrate as rice and corn. The two meals were otherwise identical, and the additional constituents were turkey, green salad, and salad dressing. Plasma glucose and insulin responses were significantly lower after the meal containing rice and corn, with the change in the insulin response being the most dramatic. These results raise the possibility that variations in source of dietary carbohydrate may have therapeutic utility in patients with impaired glucose tolerance.

Adult↗
PubMed1980

Effect of source of dietary carbohydrate on plasma glucose and insulin responses to test meals in normal subjects.

Plasma glucose and insulin responses were measured in 22 subjects after two meal tolerance tests that varied only in the food source of carbohydrate. Each meal contained 45% carbohydrate, 15% protein, and 40% fat and provided 40% of calculated daily caloric requirement. The meals elicited a similar glucose response; however, the insulin response was significantly lower when rice and corn supplied the carbohydrate as compared to potato and gelatin. The total insulin response, calculated as area under the response curve, was 60% (P less than 0.001) greater in the meal with potato and gelatin versus the rice and corn meal.

Adult↗
PubMedDate not supplied

The use of unconventional remedies among HIV-positive men living in California.

This study compared use of unconventional remedies in two groups of HIV-positive men (N = 63). Employing a multiple-choice questionnaire, the authors assessed the use of and attitudes toward unconventional remedies among two groups of white HIV-positive men similar in age, socioeconomic status, and severity of illness, all of whom lived in Northern California. One group (n = 36) participated in AIDS clinical trial protocols; the other group (n = 27) received health care at a community health center. Participants at all sites expressed positive views upon increasing unconventional remedies. Individuals enrolled in the clinical trial protocols for investigational drugs used unconventional remedies significantly less than the community health center participants, who were enrolled in an open clinical trial of hypericin, an unproven remedy.

Adult↗