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PubMedDate not supplied

Isoflavone-rich soy protein prevents loss of hip lean mass but does not prevent the shift in regional fat distribution in perimenopausal women.

OBJECTIVE: Menopause-induced estrogen deficiency increases the risk of cardiovascular disease, which is related to a shift in regional fat distribution. We tested the hypothesis that estrogen-like isoflavones in soy protein isolate (SPI+) would lessen both regional fat gain and lean loss compared with isoflavone-poor soy (SPI-). DESIGN: Perimenopausal participants (N = 69) were randomly assigned (double-blind) to 24 weeks of treatment (40 g soy or whey protein per day): SPI+ (n = 24), SPI- (n = 24), or whey control (n = 21); each participant had blood drawn in the fasted (12 hours) state, had physical activity assessed, and kept a 5-day food diary. Dual-energy x-ray absorptiometry was used to examine the effects of SPI+ on regional fat and lean tissue distribution changes in the waist, hip, and thigh regions. RESULTS: Mean body mass increased (P < 0.01) in each group, but treatment had no effect on gain in overall body mass, fat mass, or lean mass using analysis of variance. In all treatment groups combined, lean mass increased in each region; fat mass increased only in the waist region. Treatment had an effect (P = 0.039) on hip lean mass and a marginal effect (P = 0.077) on thigh fat. Regression analyses revealed that SPI+ diminished the increase in thigh fat (P = 0.018) and heightened the increase in hip lean (P = 0.035) mass. Carbohydrate intake (P = 0.006) and cohort (reflective of season; P = 0.011) contributed to the gain in thigh fat. Total protein intake (P = 0.0012), plasma insulin (P = 0.0034), and physical activity (P = 0.047) contributed to the gain in hip lean mass. CONCLUSIONS: Gain in hip lean mass was greater (P = 0.014) in SPI+ than other groups, but SPI+ did not reduce the disease-promoting menopausal shift in regional fat mass.

Adipose Tissue↗
PubMed2002

Effect of long-term strength training on glucose metabolism. Implications for individual impact of high lean mass and high fat mass on relationship between BMI and insulin sensitivity.

The aim of this study was to examine the independent effect of high lean mass on glucose metabolism, as well as its consequences on the classic relationship between BMI and insulin sensitivity (SI) in 3 groups: 1) 8 strength-trained males with BMI >27 kg/m2 (athletes); 2) 10 sedentary males with BMI >27 kg/m2 (obese); and 3) 12 sedentary males with BMI 22-25 kg/m2 (control). Body composition was measured with impedance analysis. Iv glucose tolerance test was performed at 09:00 h after overnight fast. Estimation of insulin sensitivity and glucose effectiveness by Minimal Model Approach. Plasma glucose and insulin determination by glucose-oxidase and RIA respectively. BMI and lean mass (LM) were greater in athletes than in controls, but there were no differences in fat mass (FM), basal glucose (Gb), basal insulin (Ib), glucose tolerance (Kg), SI, glucose effectiveness (Sg), acute insulin response to glucose (AIRG) and leptin. Obese showed greater FM, leptin, lb and AIRG than athletes, while SI was lower; BMI, LM, Gb, Kg and Sg were similar. BMI, FM, LM, Ib, AIRG and leptin were lower in controls than in obese, while SI index was greater; Gb, Sg and Kg were similar. We found that: 1) Resistance exercise does not modify glucose effectiveness, but can improve insulin sensitivity through FM reduction (LM augmentation alone has no effect on glucose metabolism); and 2) High BMI causes insulin resistance only if it depends on adipose tissue hypertrophy.

Adipose Tissue↗
PubMed2000

Chronic leptin administration promotes lipid utilization until fat mass is greatly reduced and preserves lean mass of normal female rats.

Leptin is a hormone synthesized and secreted from adipose tissue. To study the physiologic effects of chronic leptin treatment, normal adult female Sprague-Dawley rats were injected subcutaneously for 35 days. Twice daily injections (250 microgram/day, b.i.d.) resulted in a significant (P<0.05) decrease in food intake that was maintained for 10 days before gradually returning to control level by day 21. Leptin decreased body weight by a maximum of 12% of the initial body weight on day 22 and remained reduced for the duration of the treatment. After 35 days of treatment, visible peritoneal adipose tissue was not detected. Body composition analysis showed that chronic injection of leptin resulted in a dramatic decrease in fat content (28+/-2 to 4+/-2 g, P<0.05; mean+/-SEM) while the lean content remained unchanged. Rats pair-fed to the leptin-treated group but treated with vehicle had the same body composition (23+/-3 g fat mass) as that measured for the ad libitum fed controls. Using indirect calorimetry we observed that leptin decreased respiratory quotient and thus increased fat oxidation. Leptin also prevented energy expenditure reduction typically associated with food restriction. Leptin treatment for 35 days decreased plasma triglyceride (0.75+/-0.07 to 0.30+/-0.03 mM, P<0.05), free fatty acid (0.56+/-0.06 to 0.32+/-0.04 mM) and insulin (3.2+/-0.5 to 1. 4+/-0.4 ng/ml, P<0.05) concentrations despite the fact that food intake was normalized by day 35. Withdrawal of leptin triggered hyperphagia indicating that leptin biology remained throughout the duration of the chronic treatment. These data suggest that leptin reduces fat mass by initially decreasing appetite and by maintaining enhanced fat utilization even when food intake has returned to that of vehicle-treated control.

Animals↗
PubMed1996

Six-month overnight administration of intraperitoneal amino acids does not improve lean mass.

UNLABELLED: Intraperitoneal administration of 1% amino acid dialysis solution in patients on continuous peritoneal dialysis (CAPD) is associated with improvement in plasma amino acid concentrations and inconsistent results with respect to nitrogen balance. Whether alteration(s) in lean mass and body fat distribution also occur remains controversial. Therefore 18 patients (P), on CAPD for at least 6 months, were assigned in a prospective and controlled fashion to receive overnight either a 1% amino acid (AA-P) or a 1.36% glucose (Glu-P) containing dialysis solution. Body composition was investigated using whole body dual energy X-ray absorptiometry (Hologic QDR 1000/W). In P receiving glucose (n = 9), total body fat mass increased (+1.0 +/- 0.4 kg, mean +/- SEM, p < 0.03), whereas in patients on amino acids (n = 9), it decreased (-0.6 +/- 0.3, p < 0.02). This decrease in fat mass in AA-P was attributable to a decrease in upper body fat (-0.6 +/- 0.2, p < 0.02), whereas in Glu-P, it increased (+0.9 +/- 0.03, p < 0.03). No change in lower body fat was observed in either group. Total body lean mass remained similar in both groups during the six months of study (AA-P: 46.6 +/- 2.9 kg vs 47.0 +/- 3.0 kg, Glu-P 50.8 +/- 3.2 vs 50.1 +/- 2.2 kg baseline vs 6 months, respectively). In AA-P plasma urea concentrations increased from 25 +/- 2 to 34 +/- 3 mmol/l (p < 0.05), whereas plasma bicarbonate concentrations were similar before and after 6 months of therapy in either group. Plasma albumin and transferrin concentrations did not change in either group. Protein catabolic rate increased in AA-P (p < 0.01), whereas K x t/V did not change as a consequence of either therapy. CONCLUSION: Reduction in the amount of glucose in the peritoneal dialysate and the addition of amino acids decreases, whereas continuous dialysis with overnight glucose increases upper body fat over a 6-month period. However, no changes in protein stores were observed with the addition of amino acids. Therefore overnight peritoneal dialysis with amino acids offers minor advantages to protein-malnourished patients on CAPD, but may be of benefit in overweight CAPD patients.

Absorptiometry, Photon↗
PubMed2006

Smoking during pregnancy and offspring fat and lean mass in childhood.

OBJECTIVE: Maternal smoking during pregnancy has been shown to be associated with obesity in the offspring, but findings have been based mainly on BMI, which is derived from height and weight. This study examined the association between maternal and partner smoking during pregnancy and offspring total fat, truncal fat, and lean mass in childhood. RESEARCH METHODS AND PROCEDURES: Analysis was based on 5689 white singletons born in 1991-1992 and enrolled in the Avon Longitudinal Study of Parents and Children, with maternal smoking data recorded for at least one trimester in pregnancy and their own body composition assessed by DXA at mean age 9.9 years. RESULTS: Smoking at any time during pregnancy was associated with higher offspring BMI [0.18 (95% confidence interval, 0.12 to 0.25) standard deviation units] and total fat mass [0.17 (95% confidence interval, 0.12 to 0.23) standard deviation units], after adjustment for age, sex, height, and height squared for total fat mass. These associations were not attenuated by adjustment for the confounding factors that were measured. Maternal smoking was also associated with lean mass and, to a lesser extent, truncal fat mass. Associations with partner's smoking were in the same direction but weaker than those of the mother's for all outcomes. DISCUSSION: Maternal smoking at any time during pregnancy is associated with higher offspring total fat mass at mean age 9.9 years. However, as the associations with partner smoking were only a little weaker than those with maternal smoking, confounding by social factors rather than a direct effect of maternal smoking is a possible explanation.

Adipose Tissue↗
PubMed2005

Proximal femur bone geometry is appropriately adapted to lean mass in overweight children and adolescents.

It is unclear if the bones of overweight children are appropriately adapted to increased loads. The objective of this study was to compare bone geometry in 40 overweight (body mass index [BMI] > 85th percentile) and 94 healthy weight (BMI < or = 85th percentile) subjects, ages 4-20 years. Dual energy X-ray absorptiometry (Hologic QDR 2000) scans were analyzed at the femoral shaft (FS) and narrow neck (NN) by the Hip Structure Analysis program. Subperiosteal width, cortical thickness and indices of bone axial and bending strength (bone cross-sectional area [CSA] and section modulus [Z]) were measured from bone mass profiles. Multivariate regression models were used to compare overweight and healthy weight subjects. Z was 11 (95% CI 5, 19) and 13 (7, 20) percent higher at the FS and NN, respectively, in overweight subjects (P < 0.001), adjusted for height, maturation and gender. At the NN, higher Z was due to greater subperiosteal width [4% (2, 7)] and bone CSA [10% (5, 16]) and at the FS, to higher bone CSA [10% (5, 16)] and thicker cortices [9% (3, 15)]. When lean mass was added to the models, bone variables did not differ between overweight and healthy weight subjects (P > 0.22), with the exception of NN subperiosteal width [3% (0, 6), P = 0.04]. Fat mass did not contribute significantly to any model. In summary, proximal femur bone geometric strength in overweight children was appropriately adapted to lean mass and height but greater weight in the form of fat mass did not have an independent effect on bone bending strength. These geometric adaptations are consistent with the mechanostat hypothesis that bone strength adapts primarily to muscle forces, not to static loads represented by body weight.

Adolescent↗
PubMed1991

Handgrip dynamometry, Cybex measurements and lean mass as markers of the ageing of muscle function.

Isometric handgrip force, isokinetic knee flexion and extension torque, and anthropometric data were obtained on 67 older men and women (ranging in age from 45 to 75 years, mean 59.7 years). Hydrostatic and skinfold estimates of lean body mass were quite closely correlated with each other in this sample (r = 0.93). Handgrip force, isokinetic knee flexion and extension torque, and lean mass all decreased by 6-8% per decade over the age span examined, although in the men the loss was most marked in terms of handgrip and lean mass, whereas in the women the loss of torque in the knee muscles was dominant. Because of these differences, the handgrip data were only weakly correlated with the isokinetic strength measurements (r = 0.22), and the isokinetic data were more strongly related to lean body mass and body mass. The optimum equation for a field prediction of isokinetic strength in this age group (a combination of age, sex, age-sex interaction and lean body mass) has an error approaching 25%, with a multiple r2 of 0.37, and a standard error of the estimate (s.e.e.) of 24.5%. It is concluded that handgrip data and slow isokinetic torque measurements evaluate relatively independent aspects of the ageing of muscular function.

Aged↗
PubMed2000

Serum IGF-I is higher in gymnasts than runners and predicts bone and lean mass.

INTRODUCTION: We examined the relationships between insulin-like growth factor I (IGF-I), its binding protein (IGFBP-3), body composition, and bone mineral density (BMD) in collegiate runners (N = 13), gymnasts (N = 10), and noncompetitive women (N = 10). METHODS: Subjects were evaluated by dual-energy x-ray absorptiometry for body composition and BMD of the spine, hip, and whole body, fasting serum levels of IGF-I and IGFBP-3, and dietary intake. The ratio IGF-I/IGFBP-3 was calculated as a marker of IGF-I bioavailability. RESULTS: In ANOVA, IGF-I and IGF-I/IGFBP-3 in athletes with oligomenorrhea and amenorrhea did not differ from eumenorrheic athletes; thus, values were pooled. Lean/height2 and bone mass at the hip and spine were higher in gymnasts than runners and controls. Total caloric intake was similar between groups. IGF-I and IGF-I/IGFBP-3 differed between groups with gymnasts having higher IGF-I values than runners (397+/-58 vs 288+/-73 ng x mL(-1), P < 0.001) and higher IGF-I/IGFBP-3 than controls and runners (0.065+/-0.009 vs 0.056+/-0.008 vs 0.045+/-0.009, P = 0.0001). In simple regression, IGF-I and IGF-/IGFBP-3 were related to lean/height2 and BMD of the lumbar spine and hip (P < 0.01-0.0001). IGF-I and IGF-I/IGFBP-3 were multicollinear; thus, the ratio was used in subsequent stepwise regression. Lean mass, corrected for body surface area (height2), independently predicted spine and trochanteric BMD (R2 = 0.26, 0.28, respectively), whereas IGF-I/IGFBP-3 and lean/height2 together contributed to 48% of the variance in femoral neck BMD. CONCLUSION: We conclude that, in this group of young adult women, lower BMD in runners may be due, in part, to lower levels of IGF-I and the ratio of IGF-I-to-IGFBP-3 and that IGF-I may mediate the relationship between bone and lean mass.

Adolescent↗
PubMed2000

Percent body fat and lean mass explain the gender difference in leptin: analysis and interpretation of leptin in Hispanic and non-Hispanic white adults.

OBJECTIVE: To reassess the relationship between body fat and fasting leptin concentrations comparing plasma vs. serum assessments of leptin; ratios vs. regression adjustment for body composition; fat and lean mass vs. percent body fat; and gender-, ethnic-, and age-related variations. RESEARCH METHODS AND PROCEDURES: Subjects included 766 adults from the nondiabetic cohort of the San Luis Valley Diabetes Study examined at follow up (1997 to 1998). Body composition was determined by dual energy X-ray absorptiometry. Leptin concentrations were determined after an overnight fast. RESULTS: Fasting serum and plasma assessments of leptin were correlated with percent body fat to the same degree. Women had significantly higher serum leptin concentrations than men when leptin concentrations were divided by body mass index, fat mass in kilograms or percent body fat. The methodological problem inherent in interpreting these ratio measures is pictorially demonstrated. In regression analysis, fat mass alone did not explain the gender difference. However, lean body mass was inversely related to leptin concentrations (p < 0.0001) and explained 71% of the gender difference at a given fat mass. Percent body fat explained all of the gender difference in leptin concentrations in both Hispanics and non-Hispanic whites. Similar to findings about gender differences, ethnic- and age-related variations in the leptin-body fat association were minimized when percent body fat was employed as the body fat measure. DISCUSSION: Regression analysis and percent body fat measured with dual energy X-ray absorptiometry are recommended when assessing the relationship between leptin and body fat. Gender differences in leptin concentrations were accounted for by percent body fat in free living (no diet control), Hispanic and non-Hispanic white adults.

Absorptiometry, Photon↗
PubMed2003

Lean mass estimation by creatinine kinetics and dual-energy x-ray absorptiometry in peritoneal dialysis.

BACKGROUND: Malnutrition is widely prevalent in dialysis. Malnourished patients present depletion of somatic protein stores and a decrease in lean body mass (LBM) that can be measured by different techniques. AIMS: (1) To assess the reliability of lean mass measurements obtained by creatinine kinetics (CrK) in a group of stable peritoneal dialysis (PD) patients, using dual-energy x-ray absorptiometry (DEXA) measurements as the reference method; (2) to establish the reproducibility of LBM estimated by CrK in individual patients analyzing repeated measurement in the short term, and (3) to correlate measurements of LBM with laboratory determinations that assess nutritional status. METHODS: We performed a cross-sectional evaluation of LBM by DEXA and CrK in 39 PD patients. In 14 patients we performed repeated measurements of LBM by CrK in the short term. RESULTS: No significant difference was found in mean lean mass values estimated by both methods: mean DEXA LBM was 41.7 kg, 36.1 +/- 4.5 kg in females and 52.7 +/- 6.4 kg in males and mean CrK LBM was 41.08 kg, 37.5 +/- 6.1 kg in females and 48.1 +/- 8.4 kg in males. A good correlation was found between both techniques (r = 0.71; p < 0.003). The mean difference between the two methods was 0.638 +/- 6.95 kg (95% confidence limits: -12.98 and +14.26). A wide scatter of the differences between both methods was seen throughout the range of measurements of LBM. When LBM by CrK was repeatedly (2-3 times) measured in a period of 3-4 months in 14 patients, it had a coefficient of variation (CV) of 15.39% (range 2.89-42.88%), while body weight CV in the same period was 0.69% (range 0-1.9%). CONCLUSIONS: CrK is an unsatisfactory method for the assessment of LBM in PD patients.

Absorptiometry, Photon↗
PubMed1999

Bone loss at the proximal femur and reduced lean mass following liver transplantation: a longitudinal study.

The longevity of recipients of liver transplant may be compromised by spinal osteoporosis and vertebral fractures. However, femoral neck fractures are associated with a higher morbidity and mortality than spine fractures. As there is little information on bone loss at this clinically important site of fracture, the aim of this study was to determine whether accelerated bone loss occurs at the proximal femur following transplantation. Bone mineral density and body composition were measured at the femoral neck, lumbar spine and total body, using dual x-ray absorptiometry in 22 men and 19 women, age 46 +/- 1.4 y (mean +/- SEM) before and at a mean of 19 mo after surgery (range 3-44). Results were expressed in absolute terms (g/cm2) and as a z score. Before transplantation, z scores for bone mineral density were reduced at the femoral neck (-0.47 +/- 0.21 SD), trochanter (-0.56 +/- 0.19 SD), Ward's triangle (-0.35 +/- 0.14 SD), lumbar spine (-0.76 +/- 0.13 SD), and total body (-0.78 +/- 0.15 SD) (all P < 0.01 to < 0.001). Following transplantation, bone mineral density decreased by 8.0 +/- 1.7% at the femoral neck (P < or = 0.01) and by 2.0 +/- 1.2% at the lumbar spine (P < or = 0.05). Total weight increased by 12.2 +/- 2.3%, lean mass decreased by 5.7 +/- 1.4%, while fat mass increased from 24.1 +/- 2.0% to 35.1 +/- 1.8% (all P < or = 0.001). Patients with end-stage liver disease have reduced bone mineral density. Liver transplantation is associated with a rapid decrease in bone mineral density at the proximal femur, further increasing fracture risk and a reduction in lean (muscle) mass, which may also predispose to falls. Prophylactic therapy to prevent further bone loss should be considered in patients after liver transplantation.

Absorptiometry, Photon↗
PubMed1992

Estimation of changes in genetic parameters in selected lines of mice using REML with an animal model. 1. Lean mass.

Analysis was undertaken using Restricted Maximum Likelihood (REML) with an animal model of the results of selection for 20 generations for predicted lean mass in 10-week-old male mice. There were three replicates, each comprising high, low and unselected control lines. The overall estimates of heritability (h2) and common environmental correlations (c2) from results of the first seven generations were 0.51 +/- 0.03 and 0.21 +/- 0.01, respectively. Analyses of data from different lines and different numbers of generations were undertaken but with all pedigrees and data included, which enabled inferences to be drawn on changes in variance that were not due simply to inbreeding or short-term effects of selection. Estimates of h2 were lower in selected lines than the control, increasingly so in later generations, indicating departure from the infinitesimal model assumption of unlinked additive genes each of very small effect. In addition, values of c2 became higher in high than in control or low selected lines.

Analysis of Variance↗
PubMed2005

Reference charts for the relationships between dual-energy X-ray absorptiometry-assessed bone mineral content and lean mass in 3,063 healthy men and premenopausal and postmenopausal women.

Correlations between dual-energy X-ray absorptiometry (DXA)-assessed bone mineral content and lean mass (BMC-LM curves), and between BMC/LM ratio and age ([BMC/LM]-age curves), were analyzed in the whole body (WB), the upper limbs (ULs) and the lower limbs (LLs) of 3,063 healthy Hispanic adults. Groups of 472 men aged 25-87 years, 1,035 premenopausal (pre-MP) women aged 27-54 years, and 1,556 post-menopausal (post-MP) women aged 48-93 years were studied with a GE-Lunar DPX-Plus device. BMC-LM curves confirmed previous observations that BMC and LM masses always correlate linearly, with similar slopes within each region, but differing in intercepts according to gender and hormonal status. Multiple regression tests showed little or no independent interaction of body weight or height with those relationships. [BMC/LM]-age curves were flat in men but showed the positive influence of estrogens throughout the age range in women. Z-scored graphs of all the corresponding relationships were compiled, showing the confidence intervals for means +/-1, +/-2, and +/-3 SDs of the data (+/-1, +/-2, +/-3 z-scores) along BMC-LM and [BMC/LM]-age curves. These charts are proposed as references for assessing how well bone mass (as assessed by BMC) and muscle mass (assumed proportional to LM) follow the natural anthropometric/biomechanical proportionality in Hispanic men and women within the age range studied, employing similar devices. Charts for LLs, showing the lowest variance amongst the studied correlations and approaching the origin as an exclusive feature, could provide the most accurate reference curves. Differences between data from ULs and LLs may provide information about any eventual interaction of body-weight bearing with the general results. The proposed analysis may provide useful information for approaching a differential diagnosis between disuse-related and other types of osteopenias employing only DXA.

Absorptiometry, Photon↗
PubMed2004

Dual-energy X-ray absorptiometry measurements of fat and lean masses in subjects with eating disorders.

OBJECTIVE: The main objective was to use a dual-energy X-ray absorptiometer (DXA) to examine the total-body and regional fat and lean composition of soft tissue in subjects with and without eating disorders initially and after weight change. It was necessary also to study the effects of differences of calibration of different models of DXA scanner. DESIGN: A total of 175 women with eating disorders, including anorexia nervosa (AN) and bulimia nervosa, and 43 age-matched controls were measured for soft-tissue composition with a pencil-beam Hologic QDR 1000W scanner and results converted to be equivalent to those from a fan-beam Hologic QDR 4500A, using previously determined crosscalibration factors. Some measurements were repeated at 6 and 12 months. RESULTS: The baseline body composition of the patients covered a continuous range of fat proportions. Implausibly low fat proportions in some of the AN subjects were corrected by conversion to 4500 equivalents. The relationship between total lean mass and fat mass could be fitted equally well by a linear or linear/log regression. The relationship between leg and trunk fat was best fitted by a polynomial regression. There were weight changes in either direction in some of the subjects. The fat proportion in the total changed mass was a mean of 55%, higher in the legs and lower in the trunk, but not different between weight gainers and losers or clinical groups. The proportion was dependent on the initial fat proportion. CONCLUSIONS: Relatively small differences in fat/lean calibration of DXA scanners may lead to anomalous results in very anorexic subjects and corrections are necessary in comparing results from different instruments. Concerns expressed about preferential trunk fat accumulation during weight recovery are not well founded. Previous claims of a relationship between fat proportion in regained weight and the amount of the weight gain are not justified.

Absorptiometry, Photon↗
PubMed1998

Biases associated with genotype and sex in prediction of fat-free lean mass and carcass value in hogs.

Carcass and live measurements of 165 market hogs that represented seven genotypes were used to investigate genotype and sex biases associated with the prediction of fat-free lean mass (FFLM) and carcass value. Carcass value was determined as the sum of the product of weight of individual cuts and their average unit prices adjusted for slaughter and processing costs. Independent variables used in the prediction equations included carcass measurements, such as optical probe, midline ruler, ribbed carcass measurements, and electromagnetic scanning (EMSCAN), and live animal ultrasonic scanning. The effect of including subpopulation mean values of independent variables in the prediction equations for FFLM and carcass value was also investigated. Genotype and sex biases were found in equations in which midline backfat, ribbed carcass, EMSCAN, and live ultrasonic scanning were used as single technology sets of measurements. The prediction equations generally undervalued genotypes with above-average carcass value. Biases were reduced when measurements of combined technologies and mean adjusted variables were used. The FFLM and carcass value of gilts were underestimated, and they were overestimated of barrows. Equations that combined OP and EMSCAN technologies were the most accurate and least biased for both FFLM and carcass value. Equations that included carcass weight and midline last-rib backfat thickness measurements were the least accurate and most biased. Genotype and sex biases must be considered when predicting FFLM and carcass value.

Adipose Tissue↗
PubMed1984

Effect of interaction of gender and energy intake on lean body mass and fat mass gain in infant baboons.

The hypothesis that energy intake influences differently the composition of mass gain during the preweaning period was tested in male and female baboons. Infant baboons were fed either a high (92 kcal/100 g formula) or a low (49 kcal/100 g formula) caloric formula from birth. Body mass, lean body mass and fat mass of each baboon were measured directly at weaning (18 weeks of age). Lean mass and fat mass gained from birth to 18 weeks was estimated by using body composition data from eight newborn baboons. Both energy intake and gender significantly influenced gain of total mass, lean mass and fat mass. There was a significant gender by diet interaction effect on the gain of fat mass. When fed the high caloric formula, males gained 145 g more lean mass than females, but the increase of fat mass was approximately the same. In contrast, on the low caloric formula, males gained 150 g more lean mass than females but 74 g less fat mass than females. These results indicate that fundamental differences in the development of lean mass and fat mass exist between male and female baboons during preweaning life.

Adipose Tissue↗
PubMed2005

Glomerular filtration rate can be accurately predicted using lean mass measured by dual-energy X-ray absorptiometry.

BACKGROUND: Accurate assessment of renal function is important in the management of patients with kidney disease yet is often difficult to obtain. Formulae, designed for clinical use, have been developed to predict glomerular filtration rate (GFR) utilizing serum creatinine (Scr). Additional parameters are included in these formulae to account for variations in Scr due to differences in total body lean mass in kg (LM). Therefore, the purpose of this study was to derive a simple formula to predict GFR based on Scr and direct quantification of LM. METHODS: Ten subjects with a wide range of renal function had GFRs determined by [125I]iothalamate clearance and LM determined by dual-energy X-ray absorptiometry as well as fasting measurements of Scr, serum and 24 h urine urea nitrogen, and albumin. RESULTS: The following formula was derived using LM (kg) and Scr (mg/dl): predicted GFR=(2.4xLM)-(0.75xLMxScr). The correlation coefficient for this formula was 0.97, when compared with [125I]iothalamate clearances, and similar to the MDRD formulae (R=0.87-0.95). CONCLUSION: Although further validation is necessary, these findings suggest that total body non-invasive measurement of LM along with Scr can be used to accurately predict GFR.

Absorptiometry, Photon↗
PubMed2003

Improved net protein balance, lean mass, and gene expression changes with oxandrolone treatment in the severely burned.

OBJECTIVE: To determine the effects of the anabolic agent oxandrolone on muscle protein and gene expression in severely burned children. SUMMARY BACKGROUND DATA: The authors previously showed that oxandrolone increased net muscle protein synthesis in emaciated burned patients receiving delayed treatment for severe burns. They hypothesized that similar effects would be seen in those treated early after burn. METHODS: Thirty-two severely burned children were enrolled in a prospective randomized trial. Subjects underwent studies to assess leg protein net balance 5 days after the first excision and grafting procedure. Immediately after these studies, treatment with placebo (n = 18) or 0.1 mg/kg oxandrolone (n = 14) twice a day was started. One week after this, another net balance study was performed in each subject. Body weights and total body potassium counting were used to determine body compositional changes. Muscle biopsies were taken 1 week after treatment in oxandrolone subjects to examine gene expression changes with gene array (12,600 genes). RESULTS: Protein net balance did not change in the placebo group, while oxandrolone-treated subjects had a significant improvement. Body weights and fat free mass significantly decreased in the placebo group, while no changes were found in the oxandrolone-treated subjects. Expression changes were seen in 14 genes in the oxandrolone group compared to placebo. Some of these included myosin light chain (+2.7-fold change), tubulin (+2.3), calmodulin (-2.3), and protein phosphatase I inhibitor (-2.8). CONCLUSIONS: Oxandrolone improves protein net balance and lean mass in the severely burned. These changes are associated with increased gene expression for functional muscle proteins.

Amino Acids↗