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Biomedical subjects

S B Heymsfield

Publications and source records attributed to S B Heymsfield.

285 records · Page 16Linked to original sources
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Anthropometric assessment of the adult hospitalized patient.

Anthropometry is a technique in which simple measuring instruments are used to describe human form. By applying the measurement directly or through use of additional calculations, the practitioner can partition the body into fat and fat-free components. Quantifying these two body spaces provides information on the amount and rate of change over time in whole body energy supply and protein mass. These data can then be used in association with other indices of energy and protein metabolism. Whereas anthropometry is simple, practical, and inexpensive, the technique is limited to a qualitative tool by several sources of error. A thorough understanding of the strengths, limitations, and appropriate applications of anthropometry is essential when applying the method in clinical practice.

Anthropometry↗
PubMedDate not supplied

Application of electromagnetic and sound waves in nutritional assessment.

Four relatively new techniques that apply electromagnetic or sound waves promise to play a major role in the study of human body composition and in clinical nutritional assessment. Computerized axial tomography, nuclear magnetic resonance, infrared interactance, and ultrasonography provide capabilities for measuring the following: total body and regional fat volume; regional skeletal muscle volume; brain, liver, kidney, heart, spleen, and tumor volume; lean tissue content of triglyceride, iron, and high-energy intermediates; bone density; and cardiac function. Each method is reviewed with regard to basic principles, research and clinical applications, strengths, and limitations.

Carbon Isotopes↗
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Free amino acid formula: nitrogen utilization and metabolic effects in normal subjects.

A previous study indicated increased urea production and low nitrogen (N) retention on a free amino acid elemental formula (FAA; Vivonex-HN). The limitations of this earlier study were: irregular nitrogen absorption in the malabsorption patients, high nitrogen intake, and failure to match FAA to control formula (hydrolyzed casein; CAS; Criticare-HN) with respect to kcal/nitrogen. A more critical test of FAA quality was sought in the current study. Four healthy males received the minimal daily nitrogen requirements (0.6 g protein/kg) from either FAA or CAS in a 10-day balance study; a second balance on the alternate formula followed. Maintenance energy, minerals, and vitamins were supplied in each period. The results indicated a higher apparent nitrogen absorption (p less than 0.05) from FAA relative to CAS in the first 5 days of the balance, although these differences were no longer present in the remaining 5 days of the period. Urinary total nitrogen increased on FAA, most of which could be accounted for by urea nitrogen; urinary creatinine nitrogen, ammonia nitrogen, and uric acid nitrogen were nearly identical between formulas. The unmeasured fraction of urinary nitrogen was markedly diminished on FAA while the urea nitrogen to total nitrogen ratio was significantly increased (p less than 0.05) compared to CAS. During the initial 5 days of study nitrogen balance was lower on FAA than on CAS and this difference became significant during the last 5 days of the period (mean +/- SD for FAA = -0.42 +/- 0.59 g/D vs CAS = 0.98 +/- 0.30 g/day, p less than 0.001). Hyperglycinemia was consistently present during FAA infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Continuous nasoenteral feeding: inverse relation between infusion rate and serum levels of bilirubin.

The relation between nasoenteric formula caloric infusion rate and the serum bilirubin level was examined in 15 healthy subjects. The study protocol spanned 3 days and included fasting studies on day 1, continuous maintenance nasogastric feeding of a formula diet on day 2, and continuous feeding at a rate twice the maintenance level on day 3. Blood studies were performed in the early morning of each day. Fifteen subjects underwent the fasting measurements and the maintenance infusion, while 11 underwent all 3 days of the protocol. With the maintenance infusion serum bilirubin fell from the fasting value of (X +/- SD) 0.77 +/- 0.53 to 0.63 +/- 0.49 mg/dl for a reduction of 18% (p less than 0.05). For the subgroup of 11 subjects receiving two levels of formula infusion, fasting and maintenance serum bilirubin levels were 0.81 +/- 0.57 and 0.65 +/- 0.47 mg/dl, respectively, (p less than 0.05). With the twice maintenance infusion the plasma bilirubin decreased further to 0.46 +/- 0.29 mg/dl, a decrement of 43% relative to fasting (p less than 0.01). No other significant changes were detected during the protocol in the standard blood chemical and hematologic studies. Thus, the serum level of bilirubin is inversely related to the formula caloric infusion rate during continuous nasoenteric feeding.

Adult↗
PubMedDate not supplied

Fiber supplementation of enteral formulas: effects on the bioavailability of major nutrients and gastrointestinal tolerance.

Two fiber-supplemented enteral formulas were recently introduced for patient application, Susta II and Enrich (12.4-g and 38.5-g soy polysaccharide/2000 kcal, respectively). This investigation had a 3-fold purpose: to determine if and to what extent fiber-supplementation changes the chemical composition of stool relative to a fiber-free formula (Ensure); to establish the clinical tolerance of the two new formulas; and to quantify the effects of soy polysaccharide on nutrient bioavailability. The study was conducted in two consecutive phases: A (n = 6 subjects; random assignment to either Ensure or Susta II for 1-2 weeks followed by isocaloric cross-over to the alternate formula for an equal period of time) and B (n = 8 subjects evaluated as in phase A except Enrich replaced Ensure). Each balance week consisted of clinical/subjective monitoring, evaluation of stool composition (H2O and dry weight), apparent nutrient absorption (energy, fat, N, P, K, Ca, Mg, Zn, Na, and Cl), and metabolic balance (N, P, K, Ca, Mg, Na, and Cl). Relative to the fiber-free formula the two fiber-supplemented solutions produced increases in fecal N, fat, H2O, and minerals of variable magnitude; there were corresponding reductions in net absorption of organic compounds and minerals. The additional minerals added to the fiber-supplemented formulas and the minimal effects on N absorption preserved balance; the retention of N, P, K, Ca, Mg, Na, and Cl were similar for all three formulas. No adverse clinical effects of the fiber-supplemented formulas were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMedDate not supplied

Body composition: research and clinical advances--1993 A.S.P.E.N. research workshop.

The 1993 ASPEN Research Workshop examined research and clinical advances in the study of human body composition. The workshop had two themes: (1) compartments of the body and their measurement, and (2) clinical applications of body composition measurements. There were 12 speakers of varied backgrounds who gave short lectures followed by panel discussions. Speakers explored the validity and potential uses of new body composition methodologies, including dual-energy x-ray absorptiometry, multiple frequency bioimpedance analysis, computerized axial tomography, magnetic resonance imaging, nuclear magnetic resonance spectroscopy, neutron inelastic scattering, and gamma-ray resonance. The application of these methods to chronically and acutely ill hospitalized patients was described. The study of body composition is an emerging distinct research area within the broad study of human biology. This conference provided an overview of important new advances in the study of human body composition.

Aging↗
PubMedDate not supplied

Cardiac cachexia: preoperative and postoperative nutrition management.

The present study examined the hemodynamic and metabolic effects of nutrition support in patients with malnutrition secondary to severe mitral valve disease and congestive heart failure. Pulmonary artery pressure measurements, echocardiographic studies, gas exchange measurements, immune function tests, and clinical evaluations were made on hospitalized patients 2 weeks before and 3 weeks after surgery for valve replacement or annuloplasty. All patients received a total daily energy intake of 20 to 30 kcal/kg, four of the patients preoperatively as a combination of oral food plus parenteral nutrition and these four patients plus two additional patients as only parenteral nutrition in the early postoperative period. All six patients received nutrition support as oral food plus parenteral nutrition in the late postoperative period. Compared with baseline, nutrition support was associated with stable hemodynamic function, unchanged whole-body oxygen consumption and carbon dioxide production, and improved clinical indices both before and after surgery. Comprehensive hemodynamic, metabolic, and clinical studies thus indicate that acceptable levels of nutrition support can be provided to malnourished patients with severe congestive heart failure, which improves their clinical status and does not adversely influence cardiac function.

Aged↗
PubMedDate not supplied

Urinary 3-methylhistidine excretion: association with total body skeletal muscle mass by computerized axial tomography.

BACKGROUND: The urinary excretion of endogenous 3-methylhistidine (3-MH) has been proposed as a predictor of skeletal muscle mass (SM). In this study, we report the relationship between 24-hour urinary 3-MH excretion and SM. METHODS: Total body SM was measured by multiscan computerized axial tomography (CT) in a sample of 10 healthy adult men who followed a meat-free diet for 7 days. 3-MH was measured during the last 3 days of the meat-free diet protocol on consecutive 24-hour urine collections. RESULTS: The 3-MH excretion was 216.3 +/- 44.7 mumol/d (mean +/- SD) and was found well associated with SM (in kilograms), SM = 0.0887 x 3-MH + 11.8; r = .88, p < .001. Compared with CT, the previous 3-MH-SM prediction equation suggested by Lukaski et al underestimated SM by an average of 8.9 kg in the 10 healthy men. This difference was caused by the Burkinshaw-Cohn neutron activation model, which underestimated SM and was used as the reference in the Lukaski method. CONCLUSIONS: Twenty-four-hour urinary 3-MH excretion can be applied for estimating SM in healthy adult men on a meat-free diet.

Adipose Tissue↗
PubMedDate not supplied

Extracellular water: sodium bromide dilution estimates compared with other markers in patients with acquired immunodeficiency syndrome.

Extracellular fluid and closely related extracellular water (ECW) provide information on nutritional status in health and disease. Although various methods exist for ECW determination, little is known about their comparability in patients with wasting diseases such as acquired immunodeficiency syndrome (AIDS). One practical method, the dilution of sodium bromide (NaBr), is used widely in clinical research, although its relationship to other ECW markers has not been well characterized. The present study sought to compare ECW estimates as determined by NaBr and three other methods in 11 male patients with AIDS (mean +/- SD; age, 44+/-12 years; body weight, 64.5+/-8.8 kg; and height, 172+/-4 cm). ECW volumes were determined from NaBr dilution, total body chlorine (TBCl) by delayed gamma-neutron activation analysis, total body water (TBW) by tritium dilution combined with total body potassium (TBK) by whole body 40K counting, and radioactive sulfate dilution (35SO4). All correlations between the NaBr method and other methods were statistically significant (NaBr vs TBCl [r = .91; p < .001]; vs TBW/TBK [r = .76; p < .01]; and vs 35SO4 [r = .89; p < .001]). As expected from previous studies, ECW (L) derived by NaBr provided a group mean (15.1+/-2.2 L) similar to the TBCl method (15.4+/-1.7 L; p = .32), a significantly smaller ECW than by the TBW/TBK method (18.6+/-3.4 L; p = .0004), and a significantly larger ECW than by 35SO4 method (13.3+/-3.0 L; p = .002). Estimating ECW by NaBr dilution was comparable with other research-based ECW methods and, thus, offers a practical alternative for evaluating ECW in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Bioimpedance analysis: potential for measuring lower limb skeletal muscle mass.

BACKGROUND: Ambulation, balance, and lower extremity bone mass and strength are all partially dependent on lower limb skeletal muscle mass. At present, both research and clinical methods of evaluating lower limb skeletal muscle mass as a component of nutrition assessment are limited. One potential simple and inexpensive method is lower extremity bioimpedance analysis (BIA). The present study had two objectives: to examine the determinants of lower limb resistance, with the underlying hypothesis that fluid-containing muscle is the main electrical conductor of the lower limbs; and to establish if a correlation of equivalent magnitude and similar covariates is observed when height squared (H2) is used instead of lower limb length squared (L2) in multiple regression models relating resistance to independent variables. METHODS: Lower limb resistance was measured using a contact-electrode BIA system, and lower limb fat and skeletal muscle were estimated by dual-energy x-ray absorptiometry in healthy adults. A physical BIA model was developed in the form of a regression equation with path-length (as L2 and H2)-adjusted resistance as dependent variables and lower limb skeletal muscle, fat, age, and gender as potential independent variables. RESULTS: There were 94 subjects, 34 men and 60 women, with a mean (-/+SD) age of 41.5+/-17.8 years. Strong associations were observed between L2/resistance and lower limb skeletal muscle, although for both men and women, age entered into the model as a significant covariate (total R2, men = .79 and women = .72; both p < .001). Similar models were observed with H2/resistance as dependent variable. Additional analyses showed a significantly lower resistance in lower limb skeletal muscle and height-matched old vs young subjects. CONCLUSIONS: Strong associations exist between measured lower limb resistance and lower limb muscle mass, adjusting for electrical path length either by L2 or H2. These observations suggest the potential of predicting skeletal muscle using BIA-measured lower limb resistance adjusted for stature. Age is also an independent variable in lower limb resistance-skeletal muscle associations, suggesting the need to establish underlying mechanisms of age-related resistance effects and to consider subject age when developing BIA prediction models.

Absorptiometry, Photon↗
PubMedDate not supplied

Long-term serum lipid lowering, behavior modification, and weight loss in obese women.

Reduced calorie intake, changes in the composition of foods ingested, and increased physical activity are the usual initial recommended therapies for the obesity that often accompanies hypercholesterolemia and other hyperlipidemias. Collectively resulting in weight loss, these behavioral changes are known to produce short-term (< or = 7- to 9-mo) reductions in serum cholesterol and other lipids. In contrast, previous long-term (> or = 1-yr) investigations fail to disclose a cholesterol-lowering effect of weight loss, although the subjects in these studies were not hypercholesterolemic. The aim of our investigation was to examine the long-term changes in serum lipids that occurred in a representative cohort of healthy obese (n = 45, body mass index mean +/- SD 39.0 +/- 8.6 kg/m2) women after they completed a 15-wk conventional behavior-modification program. The serum cholesterol level of this cohort was elevated at baseline (6.18 +/- 1.41 mM, > or = 75th percentile). At the time of follow-up (17.0 +/- 7.0 mo), there were significant decreases in body weight (-16.7 kg, p < 0.001) and reductions in serum total (-0.53 mM, p < 0.01) and low-density lipoprotein (-0.35 mM, p < 0.05) cholesterol. Serum triglyceride levels also decreased significantly (-0.38 mM, p < 0.001), and serum high-density lipoprotein levels remained unchanged; the ratio of high-density lipoprotein total cholesterol increased significantly (p < 0.05) relative to baseline levels. Multiple stepwise regression analysis indicated that the best predictor of percentage change in each respective lipid was its own baseline level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗