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Biomedical subjects

M Apfelbaum

Publications and source records attributed to M Apfelbaum.

At least 55 records · Page 3Linked to original sources
PubMed1991

A kappa opiate agonist, U50,488H, enhances energy expenditure in rats.

The effect of U50,488H (a selective kappa opiate agonist) on oxygen consumption was measured in either resting and free-moving rats. In both states, U50,488H provokes an increase in oxygen consumption. In resting rats, the increase occurs at lower doses than in free-moving rats. The explanation could be that in the free-moving rats the drug results in an increase in energy expenditure, partially compensated by a decrease in activity.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1991

Resting energy expenditure is increased in stable, malnourished HIV-infected patients.

Resting energy expenditure (REE) was measured by reference to body composition in 50 malnourished patients with human immunodeficiency virus (HIV) infection and compared with that of 14 healthy subjects. Among HIV patients, 40 had acquired immune deficiency syndrome (AIDS) and 10 had AIDS-related complex (ARC). All were in stable condition and had a previous history of progressive wasting, ie, a mean body weight loss of 14.2 +/- 8.1 kg over 16.6 mo (range 2-49 ms). The mean REE was 14% higher than estimated basal energy expenditure (EBEE), according to the Harris and Benedict formula. Thirty-four patients (68%) were classified as hypermetabolic (REE greater than 110% EBEE). The best predictable variable for REE was fat-free mass (FFM), as determined by an anthropometric method (r = 0.72; P less than 0.001). The mean REE was 12% higher in HIV patients than in the control group FFM (156 +/- 19 vs 124 +/- 17 kJ.kg FFM-1.d-1). We concluded that in stable and malnourished HIV patients, the progressive wasting may be partly related to an increase in REE. The mechanism of this hypermetabolic state remains to be established.

Body Composition↗
PubMed1991

Lowering of HDL2-cholesterol and lipoprotein A-I particle levels by increasing the ratio of polyunsaturated to saturated fatty acids.

The protective role of high-density lipoproteins (HDLs) has been attributed to the subfractions HDL2 (according to the density) and lipoprotein A-I (LpA-I) (according to the composition in apolipoproteins). We investigated the effect of a high ratio of polyunsaturated to saturated fatty acids (P:S) on these subfractions in a homogeneous group of young adult males. Two prescribed diets were consumed successively at the subjects' homes for 3 wk each in a random order; one diet contained 70 g butter (P:S 0.2, diet B), the other contained 70 g sunflower margarine (P:S 1.1, diet M). Total calorie, fat, and cholesterol intakes were similar for the two diets. Cholesterol and apolipoprotein B in serum and in low-density lipoproteins (LDLs) were lower with diet M than with diet B. However, significant decreases in protective subfractions of HDL, HDL2, and LpA-I were observed. This undesirable effect of the diet with a high P:S could cancel the benefits of lowering the LDL-cholesterol concentrations.

Adult↗
PubMed1991

Energy-metabolism adaptation in obese adults on a very-low-calorie diet.

In this study, six obese women received a very-low-calorie diet (VLCD) for 3 wk. At day 0, body composition was assessed with a bioelectric impedance analyzer. The evolution in lean body mass (LBM) during the VLCD was estimated from nitrogen balance, measuring urine and fecal losses and taking into account skin, nitrate, and menstrual losses to avoid underestimation bias that could explain the decreased ratio of resting metabolic rate (RMR) to LBM previously reported. RMR was measured at days 0, 3, 5, and 21. The RMR-LBM ratio declined significantly during the VLCD period and decreased faster during the first week; the day 3, day 5, and day 21 ratio values were 94%, 91%, and 82%, respectively, of the original. The RMR-LBM ratio decrease after 21 d of a VLCD was near that found in chronic undernutrition. Results of previous studies that did not find any drop in the RMR-LBM ratio in obese adults on VLCDs might be explained by their LBM-assessment methods.

Adaptation, Physiological↗
PubMed1991

n-3 polyunsaturated fatty acids raise low-density lipoproteins, high-density lipoprotein 2, and plasminogen-activator inhibitor in healthy young men.

The effects of a moderate supplementation in n-3 polyunsaturated fatty acids (PUFAs) were investigated in 36 young healthy adult males. Factors investigated were lipoprotein (including HDL subfractions and apolipoproteins) and hemostasis indexes, assessed by platelet aggregation and plasminogen-activator-inhibitor (PAI) activity. Fat-controlled diets were prescribed, one with and one without a fish-oil supplement (control diet), successively during 3 wk in random order. Total calorie, fat, and cholesterol intakes were similar in the two diets. Triglycerides in serum and very-low-density lipoproteins were lower and high-density-lipoprotein 2 cholesterol was higher with the n-3 PUFA-supplemented diet. These effects as well as a significant decrease in platelet aggregation can be considered beneficial in terms of cardiovascular risk. However, significant increases in low-density-lipoprotein cholesterol and PAI activity occurred and were correlated. This latter effect could be detrimental.

Adult↗
PubMed1990

Distribution of HDL2 and HDL3 in a random population of healthy French males and females--evaluation by a two-step precipitation procedure.

A rapid and reliable method for the determination of HDL2 and HDL3 cholesterol is described. The Apo B containing fractions (VLDL, IDL, LDL) were precipitated by addition of dextran sulfate (Mr 500,000) to 2 mmol/l final concentration followed by MgCl2 to a final concentration of 0.05 mol/l. The supernatant, was brought to 6 mmol/l dextran sulfate and 0.250 mol/l MgCl2 to precipitate HDL2. Cholesterol determination on total serum and both supernatants yielded the concentrations of Apo B-associated cholesterol, total HDL, HDL2 and HDL3 cholesterol. The application of this technique to a random population of healthy French people gave HDL-cholesterol values of 1.35 and 1.54 mmol.l-1, respectively, in 93 males and 95 females (p less than 0.001). All of the difference was attributable to HDL2 (0.43 vs 0.65 mmol.l-1, p less than 0.001) while HDL3 were almost identical at 0.92 and 0.91 nmol.l-1. These values are in good agreement with previously reported figures for French individuals, but markedly higher in males than values reported from North America.

Apolipoproteins A↗
PubMed1990

Lack of association between dietary alcohol and HDL-cholesterol concentrations in obese women.

The relationships of alcohol intake and corpulence to HDL-cholesterol were studied in 653 women taking medical advice about body weight. The body mass index (BMI) was positively correlated with triglyceride and negatively with HDL-cholesterol. The relation between BMI and HDL-cholesterol was discontinuous. Total cholesterol, triglycerides and diastolic blood pressure were increased for alcohol intakes greater than 10 g/d regardless of body weight. Alcohol intake was associated with higher concentrations of HDL-cholesterol (P = 0.006) in non obese (BMI = 25.2 +/- 1.5 kg/m2) subjects, but not in mildly (27.3 less than or equal to BMI less than 32.3) or massively (BMI greater than or equal to 32.3) obese subjects. The fact that HDL concentrations were not associated with alcohol intake in obese patients suggests that (1) alcohol acts on the HDL pool through one of the pathways which are perturbed in obesity, possibly lipolysis, (2) obesity is one of the reasons for the differences in individual responses of HDL-cholesterol to alcohol, (3) myocardial infarction might not be inversely correlated with alcohol intake in the obese as it is in the non-obese population.

Adult↗
PubMed1990

Negative allesthesia and decreased endogenous opiate system activity in anorexia nervosa.

The combined effects of an intragastric load of glucose compared to water and of naltrexone compared to placebo were tested on preference for sucrose in six anorectic patients. While in normal subjects, glucose-induced negative allesthesia is known to disappear upon loss of weight, it persisted in anorexia nervosa (AN) despite a major weight loss; furthermore, in contrast with its effects in normoponderal subjects, naltrexone at the dose of 25 mg did not decrease the preference for sucrose nor did it enhance glucose-induced allesthesia. Basal plasma beta endorphin level determined by radioimmunoassay was higher in AN than in normal subjects (75 +/- 6.1 pmoles/l vs. 13 +/- 3.8 pmoles/l) (p less than 0.001). It is suggested that a decrease in endogenous system opiate activity might be associated with food refusal and body weight loss in anorexia nervosa.

Adolescent↗
PubMed1990

Fat-free mass estimation by the two-electrode impedance method.

In 202 healthy subjects (81 men, 121 women) aged 12-71 y, impedance (Z) was measured with a two-electrode analyzer. Fat-free mass was assessed by hydrodensitometry (FFMd). This population was randomized into two groups for cross-validation. In group 1 the relationship between ht2/Z at 1 MHz and FFMd was highly significant (r = 0.85, P less than 0.001). The equation for predicting FFMd from impedance, height2, weight, and age obtained in group 1 (r = 0.97) was applied to group 2 (r = 0.96) without reduction in r value. The accuracy of this equation was not different between men and women or between active and sedentary people. These data indicate that the two-electrode impedance method is a reliable and valid approach not only for the determination of extracellular water (as previously shown) but also for that of FFM.

Adolescent↗
PubMed1990

Obesity and iron status in menstruating women.

The relationship between iron stores and obesity in menstruating women was studied in 20 obese and 20 nonobese women matched for age and contraception. Although no difference was observed in serum iron or total-iron-binding capacity, the obese group showed significantly higher hemoglobin (137 +/- 9 vs 10 g/L, mean +/- SD; P less than 0.01), hematocrit (0.41 +/- 0.02 vs 0.39 +/- 0.03, P less than 0.05), and serum ferritin concentrations (48.0 +/- 44.3 vs 25.8 +/- 19.5 micrograms/L, P less than 0.05). There was no difference between obese and nonobese women in either the menstrual-cycle interval or the duration of the menstrual flow. Iron intake was significantly higher in the obese group (15.9 +/- 2.9 vs 14.1 +/- 2.9 mg/d, P less than 0.05). These results suggest that obese menstruating women are at low risk of depleting iron stores, possibly because of high iron intake. Iron-fortification programs might thus be undesirable in such subjects.

Adult↗
PubMed1990

Overweight treated with energy restriction and a dietary fibre supplement: a 6-month randomized, double-blind, placebo-controlled trial.

Fifty-two (41 females, 11 males) overweight patients, mean body mass index (BMI) = 29.3, were treated for 6 months in a randomized, double-blind, placebo-controlled, parallel group design. The treatment consisted of an energy restricted diet and a dietary fibre supplement amounting to 7 g/day. After treatment the weight reduction in the fibre-treated group, 5.5 +/- 0.7 kg, was significantly higher than that of the placebo group, 3.0 +/- 0.5 kg (P = 0.005). Both groups were normotensive and comparable commencing treatment, 126.5/75.6 +/- 2.0/1.3 mm Hg versus 126.7/78.7 +/- 2.5/1.6 mm Hg. The treatment changed blood pressure non-significantly. Hunger feelings using visual analogue scales (VAS) were significantly reduced from 139.8 +/- 8.2 cm to 118.3 +/- 7.0 cm in the fibre-treated group, whereas a significant increase from 129.5 +/- 6.9 cm to 146.9 +/- 8.8 cm (P less than 0.02) was seen in the placebo group. Side-effects were predominantly gastrointestinal and equally distributed in the two groups. It is concluded that a dietary fibre supplement is of value in the management of overweight, enhancing weight loss and decreasing hunger feelings.

Adult↗
PubMed1990

Circadian rhythm of energy intake and corpulence status in adults.

The relationship between circadian distribution of energy intake and corpulence was studied in 1312 subjects seeking medical advice for their weight. The corpulence categories (non-obese, mildly obese and massively obese) were defined on the basis of NHANES II. Food consumption was assessed through the dietary history method. The 24 h energy intake increased with corpulence. The lunch represented higher (P less than 0.001) proportions of daily intake in mildly and in massively obese than in non-obese. The reverse occurred for the breakfast (P less than 0.001). The relationships of corpulence with breakfast and lunch persisted after adjustment for nutrient intake. No difference was found for dinner and extra-prandial food intake. Such data suggests several behavioural and/or metabolic hypothesis.

Adult↗
PubMed1989

International trial of long-term dexfenfluramine in obesity.

In a randomised, placebo-controlled, double-blind study, 822 obese patients of both sexes were given either dexfenfluramine (dF), 15 mg twice daily (404), or placebo (418) in addition to a calorie-restricted diet for 1 year. Patients in both groups lost weight significantly in the first 6 months; after 6 months dF patients had a higher cumulative mean weight loss. Dropout rates were lower in dF patients than in placebo patients, mainly because of dissatisfaction with weight loss in the latter group. More than twice as many dF patients as placebo patients achieved a given weight loss; but more dF patients than placebo patients had transient side-effects (tiredness, diarrhoea, dry mouth, polyuria, and drowsiness).

Adult↗
PubMed1989

Effects of a low dose of naltrexone on glucose-induced allesthesia and hunger in humans.

In order to study the effects of a low dose of the opioid antagonist naltrexone on ingestive behavior for sucrose in humans, preference for sucrose solutions and feelings of hunger were scored on visual analogical scale by 14 healthy subjects with or without naltrexone. Effects of intragastric glucose load or water, and naltrexone (25 mg) or placebo were tested. At this low dose, naltrexone alone had a slight effect on allesthesia, and it produced a strong potentiation of glucose-induced allesthesia.

Adult↗
PubMed1989

[Anorexia nervosa: absence of sensitivity to nutritional protein markers. Study of 23 patients and comparison to a paired group with colonic Crohn's disease].

One of the most important therapeutic goal in anorexia nervosa is to define with the patient a body weight to obtain. To do so, objective criteria are needed. For this purpose, we studied in a longitudinal way, 9 nutritional parameters in 23 patients with anorexia nervosa, as compared with 23 age - and sex - matched patients with Crohn's disease: body weight, tricep's skinfolds, mid-arm muscle circumferences; serum albumin, prealbumin, transferrin, hemoglobin, cholesterol; urinary creatinine and calcium, magnesium, zinc and copper serum levels and urinary outputs. Despite losses of body weight, of lean body mass and of fatty mass higher in patients with anorexia nervosa than in those with Crohn's disease, the former had higher nutritional protein's serum levels than the latter. These nutritional protein markers were not in anorexia nervosa different from normal values. In anorexia patients, zinc and copper serum levels and urinary outputs were very low. This study suggests that nutritional protein markers of hepatic synthesis are not sensitive markers for malnutrition evaluation and can not be used to follow renutrition efficacy.

Adult↗
PubMed1989

A positive correlation between energy intake and body mass index in a population of 1312 overweight subjects.

The energy intake (EI) of 1312 overweight subjects was assessed using the research dietary history method. EI was positively associated with overweight--as expressed by the body mass index (BMI)--in both males and females. Such findings are at variance with earlier reports of low dietary intakes in the obese and of an inverse relationship between EI and BMI. This discrepancy could be related to the dietary-interviews method used and/or to differences in the degree of motivation of the obese subjects in the various studies. On the other hand, our results are consistent with the positive relationship between energy expenditure (EE) and BMI previously reported in the literature and with the expected EE of our subjects.

Adult↗