Percentage Of Total Body Mass Research Articles

Sensitivity of subject-specific upper body musculoskeletal model predictions to mass scaling methods

Accurate predictions of spinal loads in subject-specific musculoskeletal models require precise body segment parameters, including segment mass and center of mass (CoM) locations. Existing upper body models often assume a constant percentage of total body mass to calculate segmental masses, disregarding inter-individual variability and limiting their predictive capacity. This study evaluated the sensitivity of subject-specific upper body musculoskeletal model predictions to body mass scaling methods. The upper body segmental masses and corresponding CoM of six male subjects with varying body mass indices were computed using two mass scaling methods: the constant-percentage-based (CPB) scaling method, commonly used in AnyBody software; and our recently developed body-shape-based (BSB) method. Subsequently, these values were used by a validated musculoskeletal model to predict the muscle and disc forces in upright and flexed postures. The discrepancies between the results of the two scaling methods were compared across subjects and postures. Maximum deviations in thorax masses reached up to 7.5% of total body weight (TBW) in overweight subjects, while maximum CoM location differences of up to 35 mm were observed in normal weight subjects. The root mean squared errors (RMSE) of the CPB results, calculated with the BSB results as baseline, showed that the muscle and shear forces of the two scaling methods were quite similar (<4.5% of TBW). Though, there were small to moderate differences in compressive forces (6.5–16.0% of TBW). Thus, the compressive forces predicted with CPB method should be used with caution, particularly for overweight and obese subjects.

The Relationship between Initial Tacrolimus Metabolism Rate and Recipients Body Composition in Kidney Transplantation.

There are several premises that the body composition of kidney transplant recipients may play a role in tacrolimus metabolism early after transplantation. The present study aimed at analyzing the relationship between the body composition parameters assessed by bioimpedance analysis (BIA) and initial tacrolimus metabolism. Immediately prior to transplantation, BIA using InBody 770 device was performed in 122 subjects. Tacrolimus concentration-to-dose (C/D) ratio was calculated based on the first blood trough level measurement. There was no difference in phase angle, visceral fat area, lean body mass index (LBMI) and the proportion of lean mass as a percentage of total body mass between the subgroups of slow and fast metabolizers. However, subjects with LBMI ≥ median value of 18.7 kg/m2, despite similar initial tacrolimus dose per kg of body weight, were characterized by a significantly lower tacrolimus C/D ratio (median 1.39 vs. 1.67, respectively; p < 0.05) in comparison with the subgroup of lower LBMI. Multivariate regression analysis confirmed that age (rpartial = 0.322; p < 0.001) and LBMI (rpartial = −0.254; p < 0.01) independently influenced the tacrolimus C/D ratio. A LBMI assessed by BIA may influence the tacrolimus metabolism in the early post-transplant period and can be a useful in the optimization of initial tacrolimus dosing.

Short-Term, Combined Fasting and Exercise Improves Body Composition in Healthy Males.

Fasting enhances the beneficial metabolic outcomes of exercise; however, it is unknown whether body composition is favorably modified on the short term. A baseline-follow-up study was carried out to assess the effect of an established protocol involving short-term combined exercise with fasting on body composition. One hundred seven recreationally exercising males underwent a 10-day intervention across 15 fitness centers in the Netherlands involving a 3-day gradual decrease of food intake, a 3-day period with extremely low caloric intake, and a gradual 4-day increase to initial caloric intake, with daily 30-min submaximal cycling. Using dual-energy X-ray absorptiometry analysis, all subjects substantially lost total body mass (-3.9 ± 1.9kg; p < .001) and fat mass (-3.3 ± 1.3kg; p < .001). Average lean mass was lost (-0.6 ± 1.5kg; p < .001), but lean mass as a percentage of total body mass was not reduced. The authors observed a loss of -3.9 ± 1.9% android fat over total fat mass (p < .001), a loss of -2.2 ± 1.9% gynoid over total fat mass (p < .001), and reduced android/gynoid ratios (-0.05 ± 0.1; p < .001). Analyzing 15 preselected single-nucleotide polymorphisms in 13 metabolism-related genes revealed trending associations for thyroid state-related single-nucleotide polymorphisms rs225014 (deiodinase 2) and rs35767 (insulin-like growth factor1), and rs1053049 (PPARD). In conclusion, a short period of combined fasting and exercise leads to a substantial loss of body and fat mass without a loss of lean mass as a percentage of total mass.

Cystatin B, cathepsin L and D related to surrogate markers for cardiovascular disease in children.

ObjectiveThis study investigated potential associations between novel biomarkers for cardiovascular disease and other surrogate markers for health.MethodsCommunity sample of 170 (92 boys and 78 girls) children aged 8–11 years. Total fat mass (TBF) and abdominal fat (AFM) were measured by Dual-energy x-ray absorptiometry (DXA). Total body fat was also expressed as percentage of total body mass (BF%), and body fat distribution was calculated as AFM/TBF. Maximal oxygen uptake (VO2PEAK), systolic and diastolic blood pressure (SBP and DBP) and pulse pressure (PP) were measured. Echocardiography was performed. Left atrial size (LA) and left ventricular mass (LVM) were measured. A follow-up DXA scan was available in 152 children (84 boys and 68 girls). Frozen serum samples were analyzed for cystatin B, cathepsin L and cathepsin D.ResultsPartial correlations between cystatin B versus lnTBF, lnBF%, lnAFM, AFM/TBF, VO2PEAK and PP were; r = 0.38, 0.36, 0.38, 0.29, -0.25 and 0.25, P = 0.001 or less for all. Weaker predominantly non-significant correlations were found for cathepsin L, whereas cathepsin D was not related to any surrogate markers for health. No significant correlations were found between biomarkers and change in body fat over 2 years.ConclusionFindings from this community-based cohort of young children show that surrogate markers for cardiovascular disease such as total fat mass, percent body fat, abdominal fat, body fat distribution, maximal oxygen uptake and pulse pressure were all associated with cystatin B. This was not found for cathepsin L or cathepsin D.

Total body fat, abdominal fat, body fat distribution and surrogate markers for health related to adipocyte fatty acid-binding protein (FABP4) in children.

The aim of the study was to assess possible relationships between adipocyte fatty acid-binding protein (FABP4) and total body fat (TBF), abdominal fat, body fat distribution, aerobic fitness, blood pressure, cardiac dimensions and the increase in body fat over 2 years in a community sample of children. A cross-sectional study was used in a community sample of 170 (92 boys and 78 girls) children aged 8-11 years. TBF and abdominal fat (AFM) were measured by dual-energy X-ray absorptiometry (DXA). TBF was also expressed as percentage of total body mass (BF%), and body fat distribution was calculated as AFM/TBF. Maximal oxygen uptake (VO2PEAK) was assessed by indirect calorimetry during a maximal exercise test and scaled to body mass. Systolic and diastolic blood pressure (SBP and DBP) and pulse pressure (PP) were measured. Echocardiography was performed. Left atrial (LA) size was measured, and left ventricular mass (LVM) was calculated. A follow-up DXA scan was available in 152 children (84 boys and 68 girls). Frozen serum samples were analyzed for FABP4. Partial correlations, with adjustment for sex, between FABP4 vs. ln TBF, ln BF%, ln AFM, AFM/TBF and VO2PEAK were (r=0.69, 0.68, 0.69, 0.49 and -0.39, p<0.05 for all). Moreover, SBP, PP, LVM and LA were also weakly correlated with FABP4 (r=0.23, 0.22, 0.28 and 0.21, p<0.05 for all). Correlations between FABP4 vs. increase in TBF and AFM over 2 years were 0.29 and 0.26, p<0.05, for both. (Increase in percent body fat or change in fat distribution were not correlated.) Conclusions: Findings from this community-based cohort of young children show that increased body fat and abdominal fat, more abdominal body fat distribution, low fitness, more LVM and increased LA, increased SBP and PP were all associated with increased levels of FABP4. Increase in TBF and abdominal fat over 2 years were also associated with increased levels of FABP4.

Effect of dietary fat source on humoral immunity response of broiler chickens

Summary An experiment was conducted to study the effect of dietary fat source on immune responses of broiler chickens reared according to commercial practices. Immune measurements included weight and percentage of total body mass of the spleen, thymus and bursa of Fabricius, and responses to Sheep Red Blood Cell (SRBC) injection and vaccine titers for Newcastle Disease Virus (NDV), Infectious Bursal Disease Virus (IBDV) and Infectious Bronchitis Virus (IBV). In a completely randomised design, a total of 200 Ross 308 broiler chickens were assigned to four replicates (10 chicks) for each of five dietary treatments: 4% beef tallow; 4% canola oil; 4% sunflower oil, 2% beef tallow and 2% canola oil; and 2% beef tallow and 2% sunflower oil.

Form influences function: Anthropometry and orthostatic stability during sustained acceleration in a short arm human centrifuge

IntroductionThe goal of this study was to determine which anthropometric factors measured via air displacement plethysmography (ADP) play a significant role in augmenting orthostatic stability during sustained acceleration G-force (+G) exposure in a short arm human centrifuge (SAHC). The authors hypothesized that test subjects with a greater normalized fat free mass in percentage of total body mass (FFM%) would exhibit greater orthostatic stability during consecutive +G loads. MethodsTwenty +G naive test subjects (10 female, 10 male), were recruited for this study, in which they underwent 2 rounds of 1/2/1G-force profile in a SAHC. Before being exposed to +G, each subject underwent anthropometric analysis via ADP to ascertain total body mass (BM, kg), body volume (BV, L), body surface area (BSA, m2), normalized fat mass/fat free mass in percentage of total body mass (FM% and FFM%). During SAHC exposure, hemodynamic parameters were continuously obtained from each test subject. The measured anthropometric parameters were compared against baseline mean arterial pressure (MAP, mmHg), heart rate (HR, bpm), stroke volume (SV, mL) cardiac output (CO, Lmin−1) and systemic vascular resistance (SVR, dynscm−5) to determine correlations. ResultsFrom the 20 subjects, 13 test subjects (5 F, 8 M) completed all phases of +G exposure, and were therefore classified as having high +G tolerance (NALOC). From the 7 remaining test subjects (5 F, 2 M); 6 aborted or reduced their +G exposure, and were therefore classified as exhibiting low +G tolerance (ALOC). One subject dropped out prior to testing, and is not included in the data. Total BM, BV, and BSA were significantly higher (p<0.05) in the NALOC group. Significant correlations between baseline SV/CO and these parameters were also determined. FFM% showed no differences between the two groups, and did not exhibit any correlations with baseline hemodynamics. NALOC subjects tended to have a higher CO and SV at baseline, whereas ALOC subjects tended to exhibit higher SVR at baseline. DiscussionTotal BM, BV, and BSA were the anthropometric factors associated with orthostatic stability during +G. The higher these parameters, the higher the baseline SV, which combined contributed to greater orthostatic stability during +G. Male test subjects had an overall advantage over females via increased body dimensions and augmented cardiac function. Anthropometric analysis via ADP thus reveals critical information regarding how anthropometry influences hemodynamic function and further studies on this topic are warranted.

O-184 Obesity Level Related To Clustering Of Risk Factors For Cvd

Background and aims Obesity is associated with increased risk of cardiovascular disease (CVD) in adults. We assessed if body fat and abdominal fat are related to clustering of risk factors for CVD in younger children. Methods Cross-sectional study of 170 (92 boys and 78 girls) children aged 8–11 years, recruited from a population-based cohort. Total fat mass (TBF) and abdominal fat (AFM) were measured by DXA. Total body fat was expressed as TBFs percentage of total body mass (BF%). Maximal oxygen uptake (VO 2PEAK )was measured by indirect calorimetry. Blood was sampled and blood pressure (BP), and resting heart rate (HR) were measured and pulse pressure (PP) was calculated. Echocardiography was performed and left atrial diameter (LA) was measured, and left ventricular mass (LVM) and relative wall thickness (RWT) were calculated. Z-scores (Value for the individual-mean value for group)/SD) were calculated. Sum of z-scores for triglycerides and lipoprotein concentrations, systolic and diastolic BP, PP, HR, LVM, LA, RWT and -VO 2PEAK were calculated in boys and girls, separately, and used as an indices of clustered risk. Results Pearson correlations between ln BF% and ln AFM versus indices of clustered risk were in boys (r = 0.58 and 0.59, p Conclusions Both total body fat and abdominal fat were associated with a clustering of CVD risk factors.

Segmental torso masses in adolescent idiopathic scoliosis

BackgroundAdolescent idiopathic scoliosis is the most common type of spinal deformity whose aetiology remains unclear. Studies suggest that gravitational forces in the standing position play an important role in scoliosis progression, therefore anthropometric data is required to develop biomechanical models of the deformity. Few studies have analysed the trunk by vertebral level and none have performed investigations of the scoliotic trunk. The aim of this study was to determine the centroid, thickness, volume and estimated mass, for sections of the scoliotic trunk. MethodsExisting low-dose CT scans were used to estimate vertebral level-by-level torso masses for 20 female adolescent idiopathic scoliosis patients. ImageJ processing software was used to analyse the CT images and enable estimation of the segmental torso mass corresponding to each vertebral level. FindingsThe patients' mean age was 15.0 (SD 2.7) years with mean major Cobb angle of 52 (SD 5.9)° and mean patient weight of 58.2 (SD 11.6) kg. The magnitude of torso segment mass corresponding to each vertebral level increased by 150% from 0.6kg at T1 to 1.5kg at L5. Similarly, segmental thickness from T1–L5 increased inferiorly from a mean 18.5 (SD 2.2) mm at T1 to 32.8 (SD 3.4) mm at L5. The mean total trunk mass, as a percentage of total body mass, was 27.8 (SD 0.5) % which was close to values reported in previous literature. InterpretationThis study provides new anthropometric reference data on segmental (vertebral level-by-level) torso mass in adolescent idiopathic scoliosis patients, useful for biomechanical models of scoliosis progression and treatment.

Validity of anthropometric measurements to assess body composition, including muscle mass, in 3‐year‐old children from the SKOT cohort

Nutritional status of children is commonly assessed by anthropometry both in under and overnutrition. The link between anthropometry and body fat, the body compartment most affected by overnutrition, is well known, but the link with muscle mass, the body compartment most depleted in undernutrition, associated with infections, remains unknown. In this study, we examined the relationship between common anthropometric indices and body composition measured by dual-energy X-ray absorptiometry (DEXA) in a sample of 121 healthy 3-year-old Danish children. Appendicular (arms and legs) lean mass was used to estimate muscle mass. Overall, anthropometric measures were more effective to measure absolute size of fat, lean and muscle mass than their relative sizes. Proportion of the variance explained by anthropometry was 79% for lean mass, 76% for fat mass and 74% for muscle mass. For fat mass and lean mass expressed as percentage of total body mass, this proportion was 51% and 66%, respectively; and for muscle mass as percentage of lean mass it was 34%. All the best reduced multivariate models included weight, skinfold and gender except the model estimating the proportion of muscle mass in lean body mass, which included only mid-upper arm circumference and subscapular skinfold. The power of height in the weight-to-height ratio to determine fat mass proportion was 1.71 with a 95% confidence interval (0.83-2.60) including the value of 2 used in body mass index (BMI). Limitations of anthropometry to assess body composition, and especially for muscle mass as a proportion of lean mass, should be acknowledged.

Aerobic fitness related to cardiovascular risk factors in young children

Low aerobic fitness (maximum oxygen uptake (VO(2 PEAK))) is predictive for poor health in adults. In a cross-sectional study, we assessed if VO(2 PEAK) is related to a composite risk factor score for cardiovascular disease (CVD) in 243 children (136 boys and 107 girls) aged 8 to 11 years. VO(2 PEAK) was assessed by indirect calorimetry during a maximal exercise test and scaled by body mass (milliliters per minute per kilogram). Total body fat mass (TBF) and abdominal fat mass (AFM) were measured by Dual-energy X-ray absorptiometry. Total body fat was expressed as a percentage of total body mass (BF%) and body fat distribution as AFM/TBF. Systolic and diastolic blood pressure (SDP and DBP) and resting heart rate (RHR) were measured. The mean artery pressure (MAP) and pulse pressure (PP) were calculated. Echocardiography, 2D-guided M-mode, was performed. Left atrial diameter (LA) was measured and left ventricular mass (LVM) and relative wall thickness (RWT) were calculated. Z scores (value for the individual - mean value for group)/SD were calculated by sex. The sum of z scores for DBP, SDP, PP, MAP, RHR, LVM, LA, RWT, BF%, AFM and AFM/TBF were calculated in boys and girls, separately, and used as composite risk factor score for CVD. Pearson correlation revealed significant associations between VO(2 PEAK) and composite risk factor score in both boys (r = -0.48 P < 0.05) and in girls (r = -0.42, P < 0.05). One-way ANOVA analysis indicated significant differences in composite risk factor score between the different quartiles of VO(2 PEAK) (P < 0.001); thus, higher VO(2 PEAK) was associated with lower composite risk factor score for CVD. In conclusion, low VO(2 PEAK) is associated with an elevated composite risk factor score for CVD in both young boys and girls.

Cyclooxygenase-2 Deficiency Attenuates Adipose Tissue Differentiation and Inflammation in Mice

Obesity is associated with a variety of disorders and is a significant health problem in developed countries. One factor controlling the level of adiposity is the differentiation of cells into adipocytes. Adipocyte differentiation requires expression of peroxisome proliferator-activated receptor γ (PPARγ), which is activated by ligands to regulate expression of genes involved in adipocyte differentiation. Although 15-deoxy-Δ(12,14)-prostaglandin (PG) J(2) (15d-PGJ(2)) has long been known to be a potent activator of PPARγ, the importance of its synthesis in adipose tissue in vivo is not clear. The current study utilized mice deficient in cyclooxygenase-2 (COX-2) to examine the role of COX-2-derived PGs as in vivo modulators of adiposity. As compared with strain- and age-matched wild-type controls, the genetic deficiency of COX-2 resulted in a significant reduction in total body weight and percent body fat. Although there were no significant differences in food consumption between groups, COX-2-deficient mice showed increased metabolic activity. Epididymal adipose tissue from wild-type mice produced a significantly greater level of 15d-PGJ(2), as compared with adipose tissue isolated from mice deficient in COX-2. Furthermore, production of the precursor required for 15d-PGJ(2) formation, PGD(2), was also significantly reduced in COX-2-deficient adipose tissue. The expression of markers for differentiated adipocytes was significantly reduced in adipose tissue from COX-2-deficient mice, whereas preadipocyte marker expression was increased. Macrophage-dependent inflammation was also significantly reduced in adipose tissue of COX-2-deficient mice. These findings suggest that reduced adiposity in COX-2-deficient mice results from attenuated PPARγ ligand production and adipocyte differentiation.

Do radio collars influence mortality and reproduction? A case with ring-necked pheasants (Phasianus colchicus) in Central Italy

The effect of radio transmitters on bird survival and reproduction has been explored in the literature, and contradictory results were found. Using the Kaplan-Meier method, we estimated the mortality of female ring-necked pheasants (Phasianus colchicus) in relation to radio load (percentage of total body mass). Low-load birds showed a higher survival, particularly after 2-3 months from release, thus excluding short-term effects of handling and adjusting to packages. Reproductive success was higher for birds with low loads, but the effect was less clear. The results were not influenced by age or body mass. As a rule of thumb, using radio packages lighter than 1.5% of the body mass can be considered safe for pheasants, whereas loads above 2% may have adverse effects.

Daily physical activity related to aerobic fitness and body fat in an urban sample of children

This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8-11 years. A cross-sectional study of 225 children aged 7.9-11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual-energy x-ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days and daily accumulation of moderate-to-vigorous and vigorous activity was calculated. Significant relationships (P<0.05) existed for vigorous activity vs ln BF% (r=-0.40), ln AFM (r=-0.35), TBF/AFM (r=-0.22) and aerobic fitness (r=0.38), whereas moderate-to-vigorous activity displayed weaker relationships (-0.22, -0.18, -0.12 NS, and 0.25). Multiple regression analyses with inclusion of possible confounders concluded that vigorous activity was independently related to aerobic fitness and ln BF% or ln AFM. Moderate-to-vigorous activity was only independently related to aerobic fitness. In this population, low daily accumulation of vigorous activity was, already in children aged 8-11 years, associated with more body fat and lower aerobic fitness. A similar relation was not found for daily accumulation of moderate-to-vigorous activity.

BMI and objectively measured body fat and body fat distribution in prepubertal children

Body Mass Index (BMI) is often used as a surrogate estimate of body fat in epidemiological studies. This study explores the association between BMI, body fat and body fat distribution assessed by Dual-Energy X-Ray Absorptiometry (DXA) in younger children. Cross-sectional study of 246 children (138 boys and 108 girls) aged 8-11 years. DXA was used to quantify abdominal fat mass (AFM), total body fat (TBF) and also total body fat as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. We found close correlations between BMI vs. TBF, BF% and AFM (r = 0.94, r = 0.92 and r = 0.93) for boys and (r = 0.95, r = 0.92 and r = 0.95) for girls, respectively (P<0.05 for all r-values). However, significantly lower correlation (P<0.001 for difference between the r-values) existed for body fat distribution (r = 0.64 for boys and 0.73 for girls). Percentage body fat, TBF and AFM were all closely associated with BMI, suggesting that BMI serves as a good surrogate marker for obesity in population studies. However, a significantly lower correlation existed for BMI vs. body fat distribution, which may be a limitation when BMI is used to study cardiovascular risk factors in epidemiological studies.

Seasonal age differences in weight and biometrics of migratory Dunlins (Calidris alpina) at Eilat, Israel

This study was undertaken to understand the migratory strategies of the Dunlins (Calidris alpina) caught in Eilat, Israel, before and after they accomplish the crossing of the combined ecological barrier of the Sinai, Sahara and Sahel deserts. Between 1999–2001, a total of 410 adults and 342 juveniles were banded. The significant difference in mean wing length between birds caught in autumn and spring reflects the degree of abrasion of the outer primaries during over-wintering in Africa. Dunlins caught in Eilat in autumn and early winter had a mean wing length 1.4–1.9mm longer than in the spring. The rate of body mass increase was comparatively high and the mean body mass of the heaviest 10% of Dunlin at Eilat was 56.2g (SE ± 0.6, N = 80). The heaviest birds from Eilat carried on average about 10g of fat with a lipid index (fat mass as a percentage of total body mass) of 18%. These reserves allow a flight of approximately 1 000km, which is probably sufficient for continued migration to more southerly wintering grounds.

STELLER SEA LION BODY CONDITION INDICES

AbstractWe evaluated various measurements of mass, morphology, and blubber thickness as indices of fatness for Steller sea lions by correlation with the percentage of total body mass comprised by the sculp (%SCULP). We concluded LMD‐index was the best index evaluated because it had a relatively high r2 (0.58), had a linear relationship with %SCULP, and the intercept term was not different from O. We suggest the development of a LMD‐index for otariids would likely reduce the unexplained variation in the index. We developed a multiple regression model (r2= 0.745, P &lt; 0.001) for predicting %SCULP with LMD‐index and functions of sex, age, and season as predictor variables. Steller sea lions &lt; 5 yr of age had higher %SCULP values than those ≥ 5 yr. %SCULP declined with age for sea lions &lt; 5 yr. Both younger and older males were fatter during the winter/spring period than during summer/ fall. Females of both age classes had similar %SCULP values throughout the year. Steller sea lions are relatively lean pinnipeds; estimates of blubber and total body lipids ranged from 5% to 17% of total body mass.

Serum leptin concentration in moderate and severe obesity: relationship with clinical, anthropometric and metabolic factors.

To study clinical, anthropometric and metabolic determinants of serum leptin concentrations in a series of patients with a wide range of obesity. 400 patients, 116 males and 284 females, aged 44+/-12.3 years with body mass index (BMI) ranging from 31 to 82 kg/m2 (mean 41.4+/-7.1). Energy intake by 7-day recall, resting energy expenditure (REE) by indirect calorimetry, body composition determined by bioelectrical impedance; C index, an anthropometric index of abdominal fat distribution, and waist-hip ratio (WHR), blood glucose serum leptin concentrations, total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, uric acid, and insulin concentrations HOMA IRI (homeostastis model assessment of insulin resistance index). Leptin concentrations were higher in obese than in normal subjects and in females than in males without differences between diabetic and non-diabetic patients; leptin concentrations were not related to age and showed a strong negative association with energy intake only in the group of women with BMI less than 40. Leptin concentrations showed a direct correlation with BMI and body fat values (expressed either as percentage of total body mass or absolute fat mass) independent of age and sex. After adjustment for fat mass, leptin values higher than predicted were found in women whereas concentrations lower than predicted were found predominantly in men. Leptin showed an inverse correlation with WHR and C-index, the latter persisting also after correction for gender and fat mass. REE, but not REE/kg fat-free mass (FFM) was inversely related to leptin also after correction for sex and absolute fat mass. Leptin concentrations were directly associated with HOMA IRI, insulin and HDL cholesterol and inversely associated with triglycerides and uric acid. The relationship of leptin with HOMA IRI was still evident after adjusting for sex but was lost when absolute fat mass was added to the model; HDL cholesterol and triglycerides appeared to be variables independent of leptin concentrations even when both sex and fat mass were added to the model. In a large group of obese patients (half of whom had severe obesity, gender, BMI and fat mass accounted for the largest proportion of serum leptin concentrations variability. We found that in obese subjects there is an effect of fat distribution on leptin concentrations and that, after excluding variability due to absolute fat mass, patients with a greater amount of abdominal fat have relatively low leptin concentrations which in turn relates to a metabolic profile compatible with an increased cardiovascular risk. Women with milder obesity may retain some degree of control of food intake by leptin.

Effects of Growth Hormone Treatment for Short Stature on Calcium Homeostasis, Bone Mineralisation, and Body Composition

We investigated the effect of growth hormone (GH) treatment on mineral and vitamin D homeostasis, bone mineralisation, and body composition in short-statured children without GH deficiency (GHD). 11 children received GH (0.50 +/- 0.08 IU/kg/week) for 24 weeks. 1,25-Dihydroxyvitamin D3 levels (mean +/- SD in pmol/l) rose from a baseline of 73.7 +/- 39.2 to 114.0 +/- 32.7 at 8 weeks (p < 0.05) and 111.9 +/- 39.7 at 24 weeks (p < 0.01). Body composition evaluation using dual-energy X-ray absorptiometry revealed increased lean tissue mass and a reduction in fat tissue. As a percentage of total body mass, fat decreased from 19.0 +/- 11.8% at baseline to 17.3 +/- 11.5% at 8 weeks (p < 0.005) and 16.8 +/- 11.5% at 24 weeks (p < 0.05). L2-L4 bone mineral density was 0.637 +/- 0.155 g/cm2 at baseline and 0.666 +/- 0.160 g/cm2 at 24 weeks (NS). We conclude that recombinant human GH treatment of short children without GHD has significant effects on vitamin D homeostasis and body composition.

Nouvelles données sur la masse du squelette chez les grands cétacés (Mammalia, Cetacea)

The mass of dry and fat-free skeletons was measured in a small sample representing five species of large cetaceans: two balaenids, two balaenopterids, and one physeterid (the sperm whale). Expressed as a percentage of total body mass, skeletal mass in these animals varies from 3.5 to 5%. Such values are very close to those established previously for small to medium size toothed whales. This means that the dynamics of mass growth of the skeleton, as compared with that of the body as a whole, does not follow a positive allometry in cetaceans. Such a growth pattern differs markedly from the tendencies described in terrestrial mammals. Conversely, it is similar to that described in bony fishes. The distribution of loads within the skeletons reflects rather different functional patterns among the taxa examined here. The possible adaptive significance of these differences is discussed in reference to the locomotion of large cetaceans.