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Biomedical subjects

M Apfelbaum

Publications and source records attributed to M Apfelbaum.

At least 73 records · Page 4Linked to original sources
PubMed1979

Circadian and ultradian rhythms in the feeding behaviour and nutrient intakes of oil refinery operators with shift-work every 3--4 days.

Seven healthy adult men, five shift-workers and two non-shift-workers (from 21 to 36 years; mean = 26.4) volunteered to record what and when they ate, both at work and at home, every day, during eight consecutive weeks (Oct. - Dec. 1974). 1) All the subjects maintained the timing of main-meal (lunch and supper) during all shifts. 2) The major intake of protein and lipid was concentrated on the two main meals during all shifts. 3) Only the pattern of carbohydrate intake was modified by the shift-work: e.g. night-shift is associated with nibbling behaviour. 4) However, shift-work and in particular the occurence of nibbling behaviour did not result in change either in the mean 24 h caloric intake, or in the percentage of protein calories. 5) The comparison between the constancy of the timing of major meals and the shift of the timing of circadian rhythm acrophases of the 5 shift-workers leads to conclude that meal timing had a poor synchronizing effect, if any.

Adult↗
PubMed1978

Beta-adrenergic receptors and myogenesis.

The rat myogenic cell line, L8, contains a beta-adrenergic catecholamine-sensitive adenylate cyclase. Prior to cell fusion, and continuing thereafter, beta-adrenergic sites, as determined by the stereospecific binding of (125I)-hydroxybenqylpindolol, I1(125I)IHYP] increases from 470 to 2000 sites/cell. There is also an increase in adenylate cyclase (2-5 fold) and endogenous cAMP (5-30 fold) following stimulation by catecholamine. The dissociation constant (KD) of (125I)IHYP for unfused and fused cell-homogenates, as determined by estimation with Scatchard analysis, by direct determination at receptor concentrations well below the KD, or by association (4.6 X 10(8) M-1 min-1); and dissociation (0.028 min-1) kinetics; ranged from about 40 to 70 pM. The acquisition of beta-receptors prior to fusion in L8 cells may implicate this system in the regulation of myogenesis.

Adenylyl Cyclases↗
PubMed1977

Effects of severe diet restriction on the oxygen consumption of obese women during exercise.

Eleven moderately obese, but otherwise healthy, young women were studied for three days while being fed their normal, unrestricted diet and then again for a two week period while being fed an energy-restricted, high-protein diet--220 kcal (0.92 MJ)/day as casein. Oxygen consumption (VO2) was measured 32 times for each subject, both at rest and during bicycle exercises. For each subject oxygen consumption was significantly lower, at rest and during moderate exercise, when the subjects were being fed the restricted diet. There was no significant difference among the diet treatments at the highest activity levels. The explanation proposed (though without experimental proof) is that, during the restricted diet, the increased reverse triiodothyronine (rT3) would result in a decrease of the aerobic glycolysis and no change in the anaerobic glycolysis.

Adult↗
PubMed1977

Weight and metabolic changes induced by low carbohydrate-high fat diets in man and in rat.

Weight loss and potential toxicity of low carbohydrate-high fat diets were examined in 8 volunteer medical students given either a high fat diet or a high carbohydrate diet for 15 days, as well as in 36 Sprague-Dawley rats fed for 5 weeks a series of low carbohydrate diets (less than 1%), varying in protein and lipid proportions. A weight loss occurred with the low carbohydrate-high fat diets; serum cholesterol level increased in both man and rat; plasma triglycerides rose in man. In rat, we found an increase in hepatic lipid levels as in plasma ketone and non-esterified fatty acid concentrations. These effects seemed to be related to the increase in lipid intake rather than the lack of carbohydrates.

Adipose Tissue↗
PubMed1976

Timing of single daily meal influences relations among human circadian rhythms in urinary cyclic AMP and hemic glucagon, insulin and iron.

Relations among circadian rhythms in serum iron, glucagon and insulin and urinary cyclic AMP excretion differ drastically when diurnally active, nocturnally resting human adults consume all daily food for one week as breakfast only and for another week as dinner only - a finding of interest to diverse fields, e.g., for optimizing certain kinds of therapy or for a better utilization of calories.

Circadian Rhythm↗
PubMed1976

Relationship between plasma insulin, the size and number of adpocytes and habitual calory intake in a group of 186 obese women.

In a group of 186 obese women, no correlation was found between post-glucose load insulinemia, measured at 13:00 hrs, and the degree of overweight, nor between post-glucose insulinemia and mean adipocyte diameter. Significant correlations were found between post-glucose insulinemia and daily caloric intake, and between post-protein insulinemia and mean adipocyte diameter. Post-glucose and post-protein load insulinemia were interrelated.

Adipose Tissue↗
PubMed1976

A chronobiological investigation of fitness for work in women on a 220 cal 24 h protein diet.

In a group of nine healthy but obese women a set of tests were used to estimate several physiological and psycho-physiological variables: self-rating of hunger, mood and physical vigor, self-recording of grip-strength, muscular fatigue test, eye-hand skill, tempo, etc. Measurements were performed every 6-hours, at fixed times, during 24-hours, once a week, before (non-restricted spontaneous food intake) and for three weeks on a 220 cal. special protein diet (calcium caseinate: 55g, associated with potassium salts, water and vitamins). Findings relating to the metabolic and hormonal variables while on this diet have already been reported: (a) The diet does not alter the circadian acrophase (peak) of the variables and (b) two distinct metabolic steps occur: first a peak of gluconeogenesis and second, a phase when ketone bodies and fatty acids are used almost exclusively as source of fuel. The present findings show that so long as nitrogen remains in balance this restricted diet (a) does not change the grip strength and the muscular fatigue test; (b) does not alter the mood, the physical vigor etc. and (c) induces a statistically significant fall in "hunger" (self-rating method). We conclude that this low protein diet is compatible with non-strenuous work.

Adolescent↗
PubMed1976

[Dietary behavior during obesity].

Human alimentary behavior deals with a threefold need: energetic, hedonic and sociocultural. Among the clinical constellation offered by obese patients it could be worthwile to distinguish: 1. Some constitutional and organic obesities, pathogenesis of which does not imply an abnormality of alimentary behavior; 2. Conversely, in some other cases, psychological induced behavioral abnormalities are able to lead to an overstepping of the so called "normal" weight; 3. In other instances, the alimentary behavior reflects the elevation of the set point for weight. All these mechanisms are mutally reinforcing and could act simultaneously or successively accounting for the great variability of the individual situations. In any case environmental conditions are operating and play a pathogenic role more especially as the anatomic, physiologic and psychologic background is predisposed.

Adolescent↗
PubMed1973

[Obesity].

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Adipose Tissue↗