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Biomedical subjects

S Heshka

Publications and source records attributed to S Heshka.

41 records · Page 3Linked to original sources
PubMed1989

Dual-photon absorptiometry: comparison of bone mineral and soft tissue mass measurements in vivo with established methods.

This study extended initial observations that indicated the potential of dualphoton absorptiometry (DPA) to measure total-body bone mineral (TBBM) and fat in vivo. DPA-derived TBBM and fat were compared with established methods in 13 subjects (aged 24-94 y) who underwent measurement of body density (Db), total-body water (TBW), potassium (TBK), calcium (TBCa, delayed-gamma neutron activation), and nitrogen (prompt-gamma neutron activation). TBBM was highly correlated with TBCa (r = 0.95, p less than 0.001) and the slope of TBCa vs TBBM (0.34) was similar to Ca content of ashed skeleton (0.34-0.38). DPA-measured fat (means +/- SD, 16.7 +/- 4.9 kg) correlated significantly (r = 0.79-0.94; p less than 0.01-0.001) with fat established by Db (16.3 +/- 5.4 kg), TBW (16.0 +/- 4.3 kg), TBK (17.7 +/- 4.6 kg), combined TBW-neutron activation (17.6 +/- 5.9 kg), and means of all four methods (16.9 +/- 4.8 kg). DPA thus offers a new opportunity to study human skeleton in vivo and to quantify fat by a method independent from the classical assumption that bone represents a fixed fraction of fat-free body mass.

Adipose Tissue↗
PubMed1989

Chemical determination of human body density in vivo: relevance to hydrodensitometry.

A chemical approach to establishing human body density in vivo was developed by combining recently developed noninvasive methods. Four compartments were measured: protein (P; prompt-gamma neutron activation), water (A; 3H2O dilution), mineral (M; dual-photon absorptiometry and delayed-gamma neutron activation), and fat (F; dual-photon absorptiometry). By this model body weight is equal to P + A + M + F. This approach was applied to 13 healthy adults (8 females and 5 males). The four compartments accounted for greater than 97% actual body weight. Calculated density based upon composition agreed within 0.6 +/- 0.4% (mean +/- SD) with density (D) measured by hydrodensitometry [calculated D (g/cc) = 0.86 measured D +0.15; r = 0.94, p less than 0.001]. The average calculated lean (P + A + M) density of 1.096 +/- 0.007 g/cc agreed closely with three classic human cadaver studies (1.100 g/cc). This multicompartment approach provides a new opportunity to estimate human body density in vivo and to refine body composition methods based upon an assumed but inadequately validated constant lean density.

Absorptiometry, Photon↗
PubMedDate not supplied

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↗
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↗