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Biomedical subjects

G B Forbes

Publications and source records attributed to G B Forbes.

At least 73 records · Page 4Linked to original sources
PubMed1984

Body composition changes during recovery from anorexia nervosa: comparison of two dietary regimes.

Twelve patients with anorexia nervosa were studied on the Clinical Research Center for periods of 15 to 58 days. Five patients were fed a diet providing 20% of energy from protein and seven patients were fed a diet with only 10% of energy from protein. These patients had a reduced lean body mass in addition to a loss of body fat, and during recovery about two-thirds of the weight gain was lean tissue. The average energy cost of the weight gain was 5.3 kcal/g. There was no significant difference between the two diets for elemental metabolic balance, changes in anthropometric measures, in weight gain, or in potassium-40 counts; nor was there any difference in the energy cost of weight gain, in the rise in basal metabolic rate, or the change in hematocrit, serum albumin, or cholesterol. However, blood urea nitrogen was higher in those patients who received the high protein diet. Satisfactory nutritional rehabilitation of patients with anorexia nervosa does not require a high protein diet.

Adolescent↗
PubMed1984

New method for the estimation of lean body mass in infants (EMME instrument): validation in nonhuman models.

An innovative, safe, and rapid method suitable for the determination of lean body mass in infants is described. The machine (EMME) operates on the principle that a biologic specimen in an electromagnetic field perturbs the field proportional to its conductivity which is dependent on the amount of electrolyte present. The physical characteristics of the EMME signal are described. Experiments done with phantom infants composed of electrolyte solution and corn oil showed a very linear relationship between fat-free volume and the natural log of the EMME signal (r = 0.97). A similar relationship was noted for ground beef (r = 0.91) and live rabbits (r = 0.99). The EMME instrument appears to hold promise as a rapid noninvasive means of determining lean body mass in infants.

Adipose Tissue↗
PubMed1984

Resting metabolic rates of obese women after rapid weight loss.

Reduced energy expenditure associated with reduced energy intake has been used as an explanation for resistance to weight loss in obese patients. Decreases in serum T3 concentrations and body cell mass induced by restriction of energy intake may contribute to the reduced energy needs. In the present study, mean resting metabolic rate (RMR) was reduced by 9.4% after 5 weeks of a very low energy diet (472 Cal/day) in six obese women, and the mean serum T3 concentration decreased 46%. However, the lowest RMR values measured were similar in these subjects (mean, 1328 Cal/day; range, 1110-1578 Cal/day) to RMR values of lean women (n = 19; mean, 1241 Cal/day; range, 938-1450 Cal/day) and moderately overweight women ingesting ad libitum diets (n = 8; mean, 1335 Cal/day; range, 1064-1533). Decreases in total body potassium (10%) and 24-h urinary creatinine excretion (23%) suggested that there was a substantial loss of body cell mass during weight loss, whereas nitrogen balance suggested that changes in body cell mass were slight. These data and those of previous studies indicate that even after rapid weight loss, the resting energy requirements of obese or previously obese subjects are not abnormally low relative to those of nonobese subjects, even though the concentrations of T3, a major thermogenic hormone, are substantially reduced. The hypometabolic response to weight loss cannot explain the failure of obese subjects to lose weight on weight-reducing regimens.

Adult↗
PubMed1984

Iron overload in three generations of a family with hemoglobin Olympia.

Erythrocytosis, increased whole blood oxygen affinity, and iron overload were found in a 37-yr-old man. Electrophoretic techniques to demonstrate a hemoglobin variant showed no abnormality. Structural studies of the hemoglobin from this patient revealed an abnormal hemoglobin previously described as Hemoglobin Olympia, a high-affinity variant. Study of three generations in this family showed increased hepatic iron or iron absorption in some members of all three generations studied. The findings in this family are consistent with an increase in iron absorption due to the consequences of Hemoglobin Olympia and the heterozygous state for hemochromatosis (allele for hemochromatosis associated with HLA-A3, B7) or the presence in the family pedigree of three different alleles for hemochromatosis (alleles for hemochromatosis associated with HLA-A3. B7, HLA-A3, B15, and HLA-A9, B44) with the heterozygous state being manifest with increased iron absorption.

Absorption↗
PubMed1983

Influence of muscle wasting on oral glucose tolerance testing.

1. The effect of muscle wasting on glucose tolerance was studied. Oral glucose tolerance testing was performed in three groups of wasted patients: myotonic dystrophy (11); amyotrophic lateral sclerosis (10); other lower motor neuron disease (four). Normal subjects (11) and non-wasted neurological disease (five) controls were studied for comparison. An average decrease of 29-36% in lean body mass was present in the wasted individuals. 2. A slightly higher plasma glucose occurred at 120 min after glucose ingestion in wasted compared with non-wasted individuals (119.2 +/- 5 vs. 99.9 +/- 4 mg/100 ml, P less than 0.05). 3. Normal insulin release was seen in all patient groups except those with myotonic dystrophy, who displayed marked hyperinsulinaemia from 30 to 240 min after glucose. This excessive insulin output was not due to a greater absolute decrease in lean body mass in the myotonic dystrophy patients than in the other wasted subjects. No significant correlation between the cumulative insulin release or peak insulin values and the absolute or height adjusted lean body mass was noted within any of the wasted or non-wasted groups. 4. In contrast to the findings of many studies, only clinically insignificant glucose intolerance was detected in ambulatory wasted patients and only patients with myotonic dystrophy had abnormal insulin release. Muscle loss appeared to exert only a slight influence on glucose regulation in these wasted patients and no typical effect of muscular atrophy on pancreatic insulin release was noted.

Adolescent↗
PubMed1983

A high protein, low calorie liquid diet in the treatment of very obese adolescents: long-term effect on lean body mass.

The use of Optifast-70, a high protein liquid diet, when used in the range of 500 to 700 cal over 5 months in very obese adolescents, was associated with weight loss of 20 to 25% of initial weight of which 70 to 75% of the loss was due to fat. No significant side effects were noted. Twenty-four hour electrocardiographic monitoring showed no significant changes, and linear growth continued. Lean body mass loss was 36% of the weight lost during the first 5 wks, but was only 10% of the weight lost during the next few months. Two adolescent males had negative phosphorus and nitrogen balances over the first 4 wk, implying that males may have slightly higher phosphorus, nitrogen, and calorie requirements.

Adolescent↗
PubMed1983

Unmeasured losses of potassium in balance studies.

A comparison of changes in body K content calculated from metabolic balance and from 40K counting shows that the former technique overestimates K retention and underestimates K losses. The disparity in results by the two methods increases with increasing K intakes.

Adult↗
PubMed1983

Lean body mass in obesity.

Most obese individuals, both children and adults, have an increase in lean weight (LBM) as well as fat, the former accounting for as much as 40 percent of the excess weight in some studies. Intentional overfeeding of normal individuals augments LBM as well as fat. Human obesity thus differs from some types of experimental and hereditary obesity in animals, since these are associated with a decreased LBM. Exceptions are those individuals with Cushing's syndrome.

Adolescent↗
PubMed1981

Errors in potassium balance.

Six overweight adult subjects given a low calorie diet containing adequate amounts of nitrogen but subnormal amounts of potassium (K) were observed on the Clinical Research Center for periods of 29 to 40 days. Metabolic balance of potassium was measured together with frequent assays of total body K by 40K counting. Metabolic K balance underestimated body K loses by 11 to 87% (average 43%); the intersubject variability is such as to preclude the use of a single correction value for unmeasured losses in K balance studies.

Adult↗