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Biomedical subjects

S B Heymsfield

Publications and source records attributed to S B Heymsfield.

At least 271 records · Page 15Linked to original sources

Prevalence of growth hormone deficiency in children with cleft lip or palate.

Two hundred children 7 to 14 years of age with isolated cleft defects of the lip, palate, or both were surveyed for stature. Twelve percent were less than the third percentile in height and were designated "short." All of the short children received an endocrine evaluation. Endogenous growth hormone was examined after two days' pretreatment with stilbesteral. Four of the 25 short children with CLP had total, and four had partial, GH deficiency. Three of the GH-deficient patients were also deficient in ACTH or TSH. In contrast, in a series of 75 short (less than third percentile) children 7 to 14 years of age without cleft defect or other apparent congenital abnormality, only two had total and two had partial GH deficiency. The data suggest that children with isolated CLP have short stature about four times more often, and GH-deficiency about 40 times more often, than children without CLP. The increased prevalence of GH-deficiency may stem from the embryologic relation of adenohypophysis and oral ectoderm.

Adolescent↗

Echocardiographic study of cardiac dimensions and function in the endurance-trained athlete.

Adaptive cardiac responses to isotonic training were studied with echocardiographic measurement of cardiac dimensions and function in 20 endurance runners whose maximal aerobic capacity on the treadmill was 4.88 +/- 0.13 (mean standard error of mean) liters of oxygen/min. They were compared with 26 young sedentary control subjects whose capacity was 3.34 +/- 0.11 liters of oxygen/min (P less than 0.001). A modest degree of right and left ventricular chamber enlargement and left ventricular hypertrophy was observed in endurance runners (left ventricular mass index 140 +/- 6 g/m2 compared with 107 +/- 4 g/m2 in sedentary control subjects, (P less than 0.001). Resting heart rate was slower in endurance runners (51 +/- 2 versus 62 +/- 2 beats/min, P less than 0.001) and resting left ventricular function as evaluated with ejection fraction and maximal posterior wall shortening velocity and mean circumferential shortening velocity (VCF) was comparable or slightly depressed in endurance runners (0.98 +/- 0.03 versus 1.02 +/- 0.05 circumferences/sec [difference not significant]). This study suggests that isotonic training results in adaptive changes in ventricular volume and mass, slower heart rates that may be associated with more efficient pumping function (that is, increasing stroke volume) and insignificant alterations in resting ejection phase indexes of left ventricular function.

Adult↗

Anabolic actions of reduced and S-carbamidomethylated human growth hormone and its plasmin digest in man.

Six children aged 12-15 yr, deficient in endogenous growth hormone, were each treated, after a 7-day control period, for 7 days with 0.0168, 0.052, and 0.168 U/kg body wt3/4 human growth (hGH) (doses A, B, and C, respectively) in separate metabolic balance studies. Doses B and C caused a dose-related retention of N, P, K, Na, and Cl in ratios of 1/0.069/4.5/7.5/5.6. These ratios indicate increments in masses of protoplasm/extracellular fluid (ECF)/bone in ratios of 1/2.0/ less than 0.001. Three of the children were also treated with doses A, B, and C of reduced and carbamidomethylated hGH (RCAM-hGH). Doses B and C caused 1.2-2.8 times as much retention of N, P, and K, and 0.3-0.5 times as much retention of Na and Cl, as did the corresponding doses of hGH. The plasmin digest of RCAM-hGH gave results generally similar to RCAM-hGH. For RCAM-hGH and its plasmin digest, N, P, K, Na, and Cl were retained in ratios of about 1/0.14/5.4/2.2/2.1, indicating increments of protoplasm/ECF/bone of about 1/0.8/0.05. These findings indicate that reduction and carbamidomethylation alter the anabolic actions of hGH in man in both quantitative and qualitative manner. RCAM-hGH is more potent in stimulating enlargement of protoplasm and bone, and less potent in stimulating expansion of ECF, than is the native hormone. The profile of anabolic actions of RCAM-hGH in man does not appear to be further altered by digestion with plasmin.

Adolescent↗

Urinary excretion of the cancer-related glycoprotein EDCl: effect of chemotherapy.

The effect of chemotherapy on the urinary excretion of a cancer-related glycoprotein labeled EDCl, recently isolated from the urine of a patient with acute myelocytic leukemia, has been studied by radioimmunoassay in eight cancer patients who were excreting 200 to 500 mg/day before treatment. In five patients, chemotherapy caused marked clinical improvement, and the glycoprotein disappeared from the urine within 10 days after chemotherapy began. In the two patients with solid tumor who responded to chemotherapy, disappearance of glycoprotein EDCl from the urine preceded clinical improvement by 1 to 2 months. Four of the five responsive patients relapsed within 6 months; in each instance, the glycoprotein reappeared in the urine (greater than 100 mg/day) 2 to 5 weeks before clinical relapse. Three patients were resistant to chemotherapy, and their urinary glycoprotein did not decline during chemotherapy. Measurement of urinary glycoprotein EDCl will be useful in rapidly ascertaining which drug will be effective in a cancer patient and in predicting relapse.

Adolescent↗

Isolation and characterization of the glycoprotein (JBB5) in the urine of a patient with carcinoma of the colon.

Patient J. B. with metastatic carcinoma of the colon excreted 0.5 to 1.0 g protein daily, about one-third of which was in Molecular Weight Class 30,000 to 60,000. The major component of this class was isolated by gel filtration and ion-exchange chromatography. The purified protein, labeled JBB5, contained about 11% sialic acid, 8% hexose, and 4% hexosamine. Its molecular weight was between 51,000 and 59,000. It did not react detectably with antisera to any of the recognized normal human plasma proteins. A specific antiserum to JBB5 was raised in the rabbit. Urine from 4% of subjects with nonneoplastic illnesses reacted in double immunodiffusion with anti-JBB5. Thirty-three % positive reactions were obtained with urines from patients with advanced neoplastic disease, the percentage varying from 64% in metastatic cancer of the pancreas to 15% in chronic lymphocytic leukemia.

Adenocarcinoma↗

Counting calories--caveat emptor.

OBJECTIVE: To determine the accuracy of caloric labeling of "diet" and "health" foods and whether the accuracy differs for certain categories of food suppliers. DESIGN: Survey; "diet" and "health" foods were analyzed via bomb calorimetry and categorized as regionally distributed, nationally advertised, or locally prepared. SETTING: Foods were sampled from retail merchants throughout the borough of Manhattan, New York, NY. SAMPLE: A convenience sample of 40 food items including regionally distributed (n = 12), nationally advertised (n = 20), and locally prepared items (n = 8). MAIN OUTCOME MEASURES: Number of kilocalories per item and number of kilocalories per gram. RESULTS: All locally prepared foods had more actual than labeled kilocalories. The mean percentage of actual kilocalories greater than the labeled kilocalories (mean percentage over label) per item was 85.42% (SD = 77.88%; P = .01). Regionally distributed foods had significantly more kilocalories than were reported (P = .001 for kilocalories per item, P = .02 for kilocalories per gram) and mean percentage over label per item was 25.22% (SD = 15.58%) and per gram was 14.97% (SD = 17.95%). Nationally advertised foods did not have significantly more actual than reported kilocalories (P = .37 for per item, P = .78 for per gram). Mean percentage over label per gram was -0.01% (SD = 9.13%) and per item was 2.18% (SD = 13.93%). CONCLUSION: These findings suggest that food labels may be inadequate sources for caloric monitoring. Health care professionals should consider the accuracy of caloric labeling when advising patients to use food labels to help monitor their caloric intake.

Basal Metabolism↗

Muscularity in adult humans: proportion of adipose tissue-free body mass as skeletal muscle.

Muscularity, or the proportion of adipose tissue-free body mass (ATFM) as skeletal muscle (SM), provides valuable body composition information, especially for age-related SM loss (i.e., sarcopenia). Limited data from elderly cadavers suggest a relatively constant SM/ATFM ratio, 0.540 +/- 0.046 for men (mean +/- SD, n = 6) and 0.489 +/- 0.049 for women (n = 7). The aim of the present study was to examine the magnitude and constancy of the SM/ATFM ratio in healthy adults. Whole-body SM and ATFM were measured using multi-scan magnetic resonance imaging. The SM/ATFM ratio was 0.528 +/- 0.036 for men (n = 139) and 0.473 +/- 0.037 for women (n = 165). Multiple regression analysis indicated that the SM/ATFM ratio was significantly influenced by sex, age, body weight, and race. The four factors explained 50% of the observed between individual variation in the SM/ATFM ratio. After adjusting for age, body weight, and race, men had a larger SM/ATFM ratio than women. Both older men and women had a lower SM/ATFM ratio than younger subjects, although the relative reduction was greater in men. After adjustment for sex, age, and body weight, there were no significant differences in the SM/ATFM ratios between Asian, Caucasian, and Hispanic subjects. In contrast, African-American subjects had a significantly greater SM/ATFM ratio than subjects in the other three groups. In addition, the SM/ATFM ratio was significantly lower in AIDS patients than corresponding values in healthy subjects.

Acquired Immunodeficiency Syndrome↗

Menopausal changes in body composition and energy expenditure.

Adult American women as a group tend to gain weight with age, and many women report that their weight gain started around the time of their menopause. Moreover, as women age, there are changes in body composition that include losses in bone mineral and body cell mass, and increases in total body fat, visceral fat, and extracellular fluid. It appears as if these body composition changes begin or accelerate during the menopausal years. The importance of weight gain and changes in body composition are their associations with an increased risk of developing some malignancies, cardiovascular disease, osteoporosis, and several other clinical conditions. This overview describes selected studies of menopause and aging-associated weight gain, changes in body composition, and alterations of energy expenditure in women. Gaps in the present understanding of these changes are highlighted, and an emphasis is placed on new research methodologies for investigating body composition and energy expenditure in vivo. A concluding section of the report summarizes areas in need of future investigation.

Body Composition↗

Upper extremity skeletal muscle mass: potential of measurement with single frequency bioimpedance analysis.

This study examined the potential of single frequency (50 kHz) BIA for estimation of upper extremity skeletal muscle (SM) mass. Subjects (n = 50) were weight stable adults varying in age (X +/- SD, 51.6 +/- 17 yr) and body mass index (27.2 +/- 5.9 kg/m2). Determinants of arm to arm impedance index (length L; L2/Z) were examined using multiple regression analysis. A good correlation was observed between L2/Z and arm SM estimated by dual-energy X-ray absorptiometry (r = 0.88, p < 0.001). Additional significant model covariates were arm fat mass (p < 0.05), bone mass (p < 0.01), and age (p < 0.001). These findings suggest that upper extremity SM may be rapidly and easily quantified using a simple and inexpensive BIA system combined with appropriate age-adjusted impedance prediction equations.

Absorptiometry, Photon↗

Muscle distribution: variations with body weight, gender, and age.

UNLABELLED: Little is known about skeletal muscle distribution in healthy adults. Data were collected on 132 healthy, ambulatory, Caucasian women and men, aged 20-89 yr. Appendicular skeletal muscle mass multiple regression models were developed to assess the relationships between regional skeletal muscle and height, weight, age, ethnicity, and extremity lengths. RESULTS: (1) with an increase in body weight there is a greater relative increase in upper muscle distribution; (2) women have less upper muscle mass compared to men; (3) with increasing age there is a relative reduction in upper muscle distribution. The present results indicate that skeletal muscle is not a homogenous component, but has at least three independent factors, gender, weight, and age, influencing distribution.

Absorptiometry, Photon↗

Lean R value for DXA two-component soft-tissue model: influence of age and tissue or organ type.

Dual-energy X-ray absorptiometry (DXA) is an important new body composition method that is based on tissue attenuation of two main photon energies. When the two photon energies pass through tissue, attenuation at the lower energy compared with that at the higher energy can expressed as a ratio (R), which is used for tissue component identification. We tested whether: (1) the R value of lean tissue is related to age, and (2) the R value of lean tissue differs between soft tissue locations. Elemental content of various tissues from the literature was used. Results show that lean R values for 40 keV and 70 keV are independent of age and tissue type.

Absorptiometry, Photon↗

Enteral nutrition support: formula preparation from modular ingredients.

Many hospitalized patients are undernourished, and often this condition can be corrected by feeding one of a variety of commercial enteral formulas through a thin nasoenteral cannula. In a subset of tube feeding patients, nutritional requirements are unique, and needs cannot be met by a fixed composition formula. Modification, or de novo fabrication of the enteral formula is therefore required. Few reviews have adequately addressed some of the complexities of designing, mixing, and feeding these specialized diets. This report provides some of this information, and shows that considerably more education and research in this area is needed.

Dietary Carbohydrates↗

A simple and accurate indirect calorimetry system for assessment of resting energy expenditure.

An indirect calorimetry system was assembled from three readily available major components: a digital pneumotachograph, an oxygen analyzer, and a carbon dioxide analyzer. A one-way valve, face mask, and meteorological balloon completed the system. Accuracy was assessed by comparison to direct calorimetry in hospitalized patients undergoing enteral hyperalimentation. Each subject was on continuous infusion of formula during a 7-day metabolic balance. Direct and indirect calorimetry was performed over the last 4 days of the balance. The overall agreement between the two methods was within 1%. A simple and inexpensive calorimetry system can therefore be assembled to provide an accurate measure of resting energy expenditure.

Adult↗

Resting metabolic rate: measurement reliability.

Resting metabolic rate (RMR) usually is measured by indirect calorimetry for a brief interval, and the results are then extrapolated to 24-hr resting energy production. The aim of the current study was to examine the validity of this approach by measuring the within- and between-day variability in RMR. The RMR was measured hourly in 14 healthy adults from 8:00 am to 4:00 pm after an overnight fast on two separate days. The results indicated that, during day 1, RMR remained unchanged from early morning to late afternoon, and there was no significant difference between RMR measurements 1 through 8. Based upon analysis of variance and intraclass correlation coefficients, the averages of the first and the last three RMR measurements were found to be unreliable. RMR reliability was improved by averaging all measurements taken during the day, and maximum reliability was obtained by averaging the middle three RMR measurements. A similar pattern of results was observed during day 2, although the overall trend was for the reliability of RMR measurements to improve relative to day 1. The average RMRs on days 1 and 2 were not significantly different. These results indicate that the current practice of establishing a patient's RMR based upon a single measurement potentially can lead to large errors in determining energy needs. Measurement reliability can be improved by serially measuring RMR, eliminating the initial measurement, and averaging the remaining two to three values.

Adult↗