Dual X-ray absorptiometry model for characterizing water in the human forearm using multiple frequency bioimpedance analysis

2006 ◽  
Vol 84 (2) ◽  
pp. 181-193 ◽  
Author(s):  
Miria E. Bartolini ◽  
Kyle Wilson ◽  
Mohan Raja ◽  
Graydon H. Raymer ◽  
R. Terry Thompson ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Intracellular Water ◽  
Fat Free Mass ◽  
Whole Body ◽  
Water Volume ◽  
Bioimpedance Analysis ◽  
Multiple Frequency ◽  
X Ray ◽  
Human Forearm ◽  
Before And After

The purpose of this study was to develop a method for measuring intracellular (ICW) and extracellular water (ECW) in the human forearm using multiple frequency bioimpedance analysis (MFBIA). The approach was (i) to measure whole-body and forearm fat-free mass using dual X-ray absorptiometry (DXA); (ii) to use these measurements to estimate the fat-free mass (FFM) resistivity in both the forearm and in the whole body; and (iii) to use the ratio of these FFM resistivities to estimate the resistivity in the ICW and ECW compartments of the forearm. To first demonstrate the accuracy of the DXA software in differentiating lean body mass from fat and bone within a volume of tissue, ex-vivo bovine muscle tissue samples (n = 3) were used to approximate the physical properties of the human forearm. It was found that although the human whole-body software overestimates FFM, it was slightly underestimated by the small animal software. Using this technique, DXA measures of FFM were obtained from human volunteers (n = 11; age = 20 ± 5 years; height = 170 ± 12 cm; mass = 64 ± 16 kg). These measures were used in conjunction with MFBIA measures of impedance of the whole body and of the forearm to determine the resistivities of the ICW and ECW compartments of the forearm, namely 375.8 ± 25.2 Ωcm and 55.6 ± 3.7 Ωcm, respectively. These were used in MFBIA equations to calculate the ICW, ECW, and total arm water (TAW) volumes of the human forearm. The calculated TAW and the ECW (± SD) volume fraction (667.29 ± 200.15 mL and 0.169 ± 0.039 mL, respectively) were in agreement with literature values. MFBIA results were compared with those obtained using nuclear magnetic resonance relaxometry (NMRR). MFBIA was performed on 15 subjects before and after an intense maximal handgrip exercise to estimate changes in water volume in muscle. Following exercise, the total and intracellular water of the forearm increased on average by 8% ± 3% and 10% ± 4% (mean ± SD), respectively. In 5 healthy volunteers, MFBIA and NMRR were performed before and after a similar exercise of the forearm muscle. The changes with exercise of intracellular and total arm water volumes as measured by MFBIA were estimated. The percent increases in total water were found to be 9.4% ± 4.2% and 9.4% ± 2.6% and in intracellular water were found to be 10.6% ± 4.6% and 12.0% ± 2.8% (mean ± SD) for NMRR and MFBIA, respectively. The results show that the exercise-induced changes in ICW and TAW determined with the MFBIA model are consistent with those observed with NMRR and radiotracer literature.

Effects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis

2001 ◽  
Vol 91 (3) ◽  
pp. 1041-1047 ◽  
Author(s):  
G. Parise ◽  
S. Mihic ◽  
D. MacLennan ◽  
K. E. Yarasheski ◽  
M. A. Tarnopolsky
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Fat Free Mass ◽  
Whole Body ◽  
Synthetic Rate ◽  
Fractional Synthetic Rate ◽  
Before And After ◽  
Total Creatine ◽  
Plasma Leucine

Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men ( n = 13) and women ( n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3–4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of l-[1-13C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (−19.6%) and plasma leucine rate of appearance (−7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.

Dual-energy X-ray absorptiometry lean soft tissue hydration: independent contributions of intra- and extracellular water

2004 ◽  
Vol 287 (5) ◽  
pp. E842-E847 ◽  
Author(s):  
Marie-Pierre St-Onge ◽  
ZiMian Wang ◽  
Mary Horlick ◽  
Jack Wang ◽  
Steven B. Heymsfield
Keyword(s):  
Soft Tissue ◽  
Water Distribution ◽  
Dual Energy ◽  
Healthy Adults ◽  
Intracellular Water ◽  
Whole Body ◽  
Extracellular Water ◽  
Cross Sectional ◽  
Total Group ◽  
X Ray

Dual-energy X-ray absorptiometry (DEXA) provides a measure of lean soft tissue (LST). LST hydration, often assumed to be constant, is relevant to several aspects of DEXA body composition estimates. The aims of this study were to develop a theoretical model of LST total body water (TBW) content and to examine hydration effects with empirically derived model coefficients and then to experimentally test the model's prediction that, in healthy adults, LST hydration is not constant but varies as a function of extra- and intracellular water distribution (E/I). The initial phase involved TBW/LST model development and application with empirically derived model coefficients. Model predictions were then tested in a cross-sectional study of 215 healthy adults. LST was measured by DEXA, extracellular water (ECW) by NaBr dilution, intracellular water (ICW) by whole body 40K counting, and TBW by 2H2O dilution. TBW estimates, calculated as ECW + ICW, were highly correlated with ( r = 0.97, SEE = 2.1 kg, P < 0.001) and showed no significant bias compared with TBW measured by 2H2O. Model-predicted TBW/LST was almost identical to experimentally derived values (means ± SD) in the total group (0.767 vs. 0.764 ± 0.028). LST hydration was significantly correlated with E/I (total group, r = 0.30, SEE = 0.027, P < 0.001). Although E/I increased with age (men, r = 0.48; women, r = 0.37; both P < 0.001), the association between TBW/LST and age was nonsignificant. Hydration of the DEXA-derived LST compartment is thus not constant but varies predictably with ECW and ICW distribution. This observation has implications for the accuracy of body fat measurements by DEXA and the use of TBW as a means of checking DEXA system calibration.

scholarly journals Whole body leucine flux in HIV-infected patients treated with or without protease inhibitors

2006 ◽  
Vol 290 (4) ◽  
pp. E685-E693 ◽  
Author(s):  
Magali Prod’homme ◽  
Cécile Rochon ◽  
Michèle Balage ◽  
Henri Laurichesse ◽  
Igor Tauveron ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Metabolism ◽  
Glucose Infusion ◽  
Fat Free Mass ◽  
Whole Body ◽  
Constant Infusion ◽  
Body Protein ◽  
X Ray ◽  
Immunodeficiency Virus

The present study was carried out to assess the effects of protease inhibitor (PI) therapy on basal whole body protein metabolism and its response to acute amino acid-glucose infusion in 14 human immunodeficiency virus (HIV)-infected patients. Patients treated with PIs (PI+, 7 patients) or without PIs (PI−, 7 patients) were studied after an overnight fast during a 180-min basal period followed by a 140-min period of amino acid-glucose infusion. Protein metabolism was investigated by a primed constant infusion of l-[1-13C]leucine. Dual-energy X-ray absorptiometry for determination of fat-free mass (FFM) and body fat mass measured body composition. In the postabsorptive state, whole body leucine balance was 2.5 times ( P < 0.05) less negative in the PI+ than in the PI− group. In HIV-infected patients treated with PIs, the oxidative leucine disposal during an acute amino acid-glucose infusion was lower (0.58 ± 0.09 vs. 0.81 ± 0.07 μmol·kg FFM−1·min−1 using plasma [13C]leucine enrichment, P = 0.06; or 0.70 ± 0.10 vs. 0.99 ± 0.08 μmol·kg FFM−1·min−1 using plasma [13C]ketoisocaproic acid enrichment, P = 0.04 in PI+ and PI− groups, respectively) than in patients treated without PIs. Consequently, whole body nonoxidative leucine disposal (an index of protein synthesis) and leucine balance (0.50 ± 0.10 vs. 0.18 ± 0.06 μmol·kg FFM·−1·min−1 in PI+ and PI− groups respectively, P < 0.05) were significantly improved during amino acid-glucose infusion in patients treated with PIs. However, whereas the response of whole body protein anabolism to an amino acid-glucose infusion was increased in HIV-infected patients treated with PIs, any improvement in lean body mass was detected.

scholarly journals Effects of whole-body electromyostimulation on function, muscle mass, strength, social participation, and falls-efficacy in older people: A randomized trial protocol

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245809
Author(s):  
Túlio Medina Dutra de Oliveira ◽  
Diogo Carvalho Felício ◽  
José Elias Filho ◽  
João Luiz Quagliotti Durigan ◽  
Diogo Simões Fonseca ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Social Participation ◽  
Positive Impact ◽  
The Elderly ◽  
Good Choice ◽  
Fat Free Mass ◽  
Whole Body ◽  
Control Group ◽  
Before And After ◽  
Physical Limitations

Background Resistance training has a positive impact on functional capacity and muscle mass in the elderly. However, due to physical limitations or a simple aversion against regular exercise, a majority of the elderly do not reach the recommended exercise doses. This led us to evaluate the effect of whole-body electromyostimulation (WB-EMS), a novel, time-efficient, and smooth training technology on physical function, fat-free mass, strength, falls-efficacy, and social participation of the elderly. Methods The present study is a randomized, parallel group clinical trial approved by the Ethics Committee of our Institution. Sixty-six volunteers (age ≥ 60 years) will be recruited from the geriatric outpatient department in a tertiary hospital and primary care units and randomized into two groups: WB-EMS group or active control group (aCG). The WB-EMS or aCG protocol will consist of 16 sessions for 8 consecutive weeks, twice per week. The primary outcomes will be maximal isometric knee extension (IKE), functional lower extremity strength, fat-free mass, gait speed, and risk of falls measured before and after intervention. The secondary outcomes will be social participation and falls-efficacy assessed before and after the intervention and at three and six months of follow-up. Participant’s satisfaction with and awareness of electrical stimulation therapy will also be assessed immediately after the 8-week intervention. Discussion Patients receiving WB-EMS exercises are believed to have better outcomes than those receiving conventional, more time-consuming resistance exercises. Hence, innovative, time-efficient, joint-friendly, and highly individualized exercise technologies (such as WB-EMS) may be a good choice for the elderly with time constraints, physical limitations, or little enthusiasm, who are exercising less than the recommended amounts for impact on muscle mass, strength, and function.

Influence of Re-Melting Technology on Properties and Microstructures of Ferrous Matrix Composites Reinforced with Tungsten Carbide Particle

2011 ◽  
Vol 291-294 ◽  
pp. 1389-1392
Author(s):  
Yan Pei Song ◽  
Hui Gai Wang ◽  
Zhi Ming Feng ◽  
Zhen Kai Zhao
Keyword(s):  
Volume Fraction ◽  
Centrifugal Casting ◽  
Outer Region ◽  
Casting Process ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Kg Medium ◽  
The Impact

The scrap WCP/Fe-C composites were re-melted in a 50 kg medium frequency induction furnace. A regenerated composites ring was manufactured by centrifugal casting process. The microstructure and properties of the composites before and after re-melting were investigated by SEM with energy dispersive spectroscopy and X-ray diffraction. The results showed that the microstructure of the composites after re-melting was composed of un-dissolved WCP, bainite, bone-like crystallites and graphite. The un-dissolved WCPwere uniformly distributed in the outer region of the regenerated composites ring, their volume fraction attained to about 65 vol. %, and size of the un-dissolved WCPwas obviously smaller than that of the WCPbefore re-melting. The impact toughness of the regenerated composites was below those of the composites before re-melting, the hardness and wear resistance of the regenerated composites were almost same as those of the composites before re-melting under the same test conditions.

Fasting inhibits insulin-mediated glycolysis and anaplerosis in human skeletal muscle

1991 ◽  
Vol 261 (5) ◽  
pp. E598-E605 ◽  
Author(s):  
C. E. Castillo ◽  
A. Katz ◽  
M. K. Spencer ◽  
Z. Yan ◽  
B. L. Nyomba
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Glycogen Synthase ◽  
Fat Free Mass ◽  
Whole Body ◽  
Glucose Disposal ◽  
Glycolytic Flux ◽  
Quadriceps Femoris Muscle ◽  
Before And After ◽  
Femoris Muscle

uglycemic (approximately 5.5 mM) hyperinsulinemic (60 mU.m-2.min-1) clamps were performed for 2 h after a 10-h fast and after a prolonged (72-h) fast. Biopsies were obtained from the quadriceps femoris muscle before and after each clamp. The rate of whole body glucose disposal was approximately 50% lower during the clamp after the 72-h fast (P less than or equal to 0.001). The increase in carbohydrate (CHO) oxidation (which is proportional to glycolysis) during the clamp after the 10-h fast (to 13.8 +/- 1.5 mumol.kg fat free mass-1.min-1) was completely abolished during the clamp after the 72-h fast (1.7 +/- 0.6; P less than or equal to 0.001). During the clamp after the 10-h fast, postphosphofructokinase (PFK) intermediates and malate in muscle increased, whereas glutamate decreased (P less than or equal to 0.05-0.001 vs. basal) and citrate did not change. During the clamp after the 72-h fast, there were no significant changes in post-PFK intermediates or glutamate (P greater than 0.05 vs. basal), but there was a decrease in citrate (P less than or equal to 0.01 vs. basal). Euglycemic hyperinsulinemia increased glycogen synthase fractional activity in muscle under both conditions but to a greater extent after the 72-h fast (P less than or equal to 0.01). It is concluded that insulin (after 10-h fast) increases glycolytic flux and the content of malate in muscle, which is probably due to increased anaplerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Density of the fat-free mass and estimates of body composition in male weight trainers

1996 ◽  
Vol 80 (6) ◽  
pp. 2085-2096 ◽  
Author(s):  
C. M. Modlesky ◽  
K. J. Cureton ◽  
R. D. Lewis ◽  
B. M. Prior ◽  
M. A. Sloniger ◽  
...  
Keyword(s):  
White Men ◽  
Dual Energy ◽  
Fat Free Mass ◽  
Whole Body ◽  
Body Density ◽  
X Ray ◽  
Musculoskeletal Development ◽  
Four Component Model ◽  
Weight Trainers ◽  
Deuterium Dilution

The purpose of this study was to determine whether the assumed density and composition of the fat-free mass (FFM) and estimates of percent fat (%Fat) from body density by use of the Siri equation (%Fatd) are valid in weight trainers with high musculoskeletal development. Measures of body density by underwater weighing (Db), body water by deuterium dilution, and bone mineral by whole body dual-energy X-ray absorptiometry were obtained in young white men: 14 weight trainers with high musculoskeletal development and 14 non-weight-training controls with average musculoskeletal development. %Fatd was significantly higher (P < or = 0.05) than %Fat estimated from body density, water, and mineral (%Fatd,w,m) by use of a four-component model in weight trainers (17.3 +/- 4.6 vs. 13.2 +/- 5.1%) but not in controls (14.8 +/- 3.1 vs. 14.2 +/- 3.6%). The greater discrepancy between %Fatd and %Fatd,w,m was explained by lower density of fat-free mass (Dffm) in weight trainers (1.089 +/- 0.005 g/ml) than in controls (1.099 +/- 0.007 g/ml). The lower Dffm in the weight trainers was due to higher water (74.8 +/- 1.2 vs. 72.6 +/- 20%) and lower mineral (5.3 +/- 0.6 vs. 5.9 +/- 0.4%) and protein (19.9 +/- 1.4 vs. 21.5 +/- 1.9%) fractions of the FFM. We conclude that, in young white men with high musculoskeletal development, Dffm is lower than the assumed value of 1.1 g/ml and %Fat is overestimated from Db by use of the Siri equation.

scholarly journals Techniques for the study of energy balance in man

2003 ◽  
Vol 62 (2) ◽  
pp. 529-537 ◽  
Author(s):  
Marinos Elia ◽  
Rebecca Stratton ◽  
James Stubbs
Keyword(s):  
Body Composition ◽  
Measurement Error ◽  
Energy Balance ◽  
Energy Intake ◽  
Dual Energy ◽  
The Body ◽  
Fat Free Mass ◽  
Whole Body ◽  
X Ray ◽  
Body Segments

Energy balance can be estimated in tissues, body segments, individual subjects (the focus of the present article), groups of subjects and even societies. Changes in body composition in individual subjects can be translated into changes in the energy content of the body, but this method is limited by the precision of the techniques. The precision for measuring fat and fat-free mass can be as low as 0.5 kg when certain reference techniques are used (hydrodensitometry, air-displacement plethysmography, dual-energy X-ray absorptiometry), and approximately 0.7 kg for changes between two time points. Techniques associated with a measurement error of 0.7 kg for changes in fat and fat-free mass (approximately 18MJ) are of little or no value for calculating energy balance over short periods of time, but they may be of some value over long periods of time (18 MJ over 1 year corresponds to an average daily energy balance of 70 kJ, which is <1% of the normal dietary energy intake). Body composition measurements can also be useful in calculating changes in energy balance when the changes in body weight and composition are large, e.g. >5–10 kg. The same principles can be applied to the assessment of energy balance in body segments using dual-energy X-ray absorptiometry. Energy balance can be obtained over periods as short as a few minutes, e.g. during measurements of BMR. The variability in BMR between individuals of similar age, weight and height and gender is about 7–9%, most of which is of biological origin rather than measurement error, which is about 2%. Measurement of total energy expenditure during starvation (no energy intake) can also be used to estimate energy balance in a whole-body calorimeter, in patients in intensive care units being artificially ventilated and by tracer techniques. The precision of these techniques varies from 1 to 10%. Establishing energy balance by measuring the discrepancy between energy intake and expenditure has to take into consideration the combined validity and reliability of both components. The measurement error for dietary intake may be as low as 2–3% in carefully controlled environments, in which subjects are provided only with certain food items and bomb calorimetry can be undertaken on duplicate samples of the diet. Reliable results can also be obtained in hospitalised patients receiving enteral tube feeding or parenteral nutrition as the only source of nutrition. Unreliability increases to an unknown extent in free-living subjects eating a mixed and varied diet; thus, improved methodology is needed for the study of energy balance.

Whole body and regional body composition changes following 10-day hypoxic confinement and unloading–inactivity

2014 ◽  
Vol 39 (3) ◽  
pp. 386-395 ◽  
Author(s):  
Tadej Debevec ◽  
Adam C. McDonnell ◽  
Ian A. Macdonald ◽  
Ola Eiken ◽  
Igor B. Mekjavic
Keyword(s):  
Body Composition ◽  
Energy Intake ◽  
Body Mass ◽  
Bed Rest ◽  
Whole Body ◽  
Short Term ◽  
X Ray ◽  
Regional Body Composition ◽  
Before And After ◽  
Composition Changes

Future planetary habitats will expose inhabitants to both reduced gravity and hypoxia. This study investigated the effects of short-term unloading and normobaric hypoxia on whole body and regional body composition (BC). Eleven healthy, recreationally active, male participants with a mean (SD) age of 24 (2) years and body mass index of 22.4 (3.2) kg·m−2 completed the following 3 10-day campaigns in a randomised, cross-over designed protocol: (i) hypoxic ambulatory confinement (HAMB; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), (ii) hypoxic bed rest (HBR; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), and (iii) normoxic bed rest (NBR; FIO2 = 0.209; PIO2 = 133.5 (0.7) mm Hg). Nutritional requirements were individually precalculated and the actual intake was monitored throughout the study protocol. Body mass, whole body, and regional BC were assessed before and after the campaigns using dual-energy X-ray absorptiometry. The calculated daily targeted energy intake values were 2071 (170) kcal for HBR and NBR and 2417 (200) kcal for HAMB. In both HBR and NBR campaigns the actual energy intake was within the targeted level, whereas in the HAMB the intake was lower than targeted (–8%, p < 0.05). Body mass significantly decreased in all 3 campaigns (–2.1%, –2.8%, and –2.0% for HAMB, HBR, and NBR, respectively; p < 0.05), secondary to a significant decrease in lean mass (–3.8%, –3.8%, –4.3% for HAMB, HBR, and NBR, respectively; p < 0.05) along with a slight, albeit not significant, increase in fat mass. The same trend was observed in the regional BC regardless of the region and the campaign. These results demonstrate that, hypoxia per se, does not seem to alter whole body and regional BC during short-term bed rest.

scholarly journals Estimation of body composition from bioelectrical impedance of body segments: Comparison with dual-energy X-ray absorptiometry

1993 ◽  
Vol 69 (3) ◽  
pp. 645-655 ◽  
Author(s):  
S. P. Stewart ◽  
P. N. Bramley ◽  
R. Heighton ◽  
J. H. Green ◽  
A. Horsman ◽  
...  
Keyword(s):  
Body Composition ◽  
Muscle Mass ◽  
Bioelectrical Impedance ◽  
Dual Energy ◽  
Fat Free Mass ◽  
Whole Body ◽  
Simple Method ◽  
Creatinine Excretion ◽  
X Ray ◽  
Body Segments

In twenty-eight healthy subjects, ten men and eighteen women, with a range in body mass index (BMI) of 17.9–31.6 kg/m2 and an age range 20–60 years, body composition was estimated by dual-energy X-ray absorptiometry (DEXA), skinfold anthropometry (SFA) and bioelectrical impedance analysis (BIA) of the ‘whole body’and body segments. In thirteen subjects muscle mass was also estimated by 24 h urinary creatinine excretion. The relationship between fat-free mass (FFM) determined by DEXA and the impedance index of each body segment (calculated as Iength2/impedance (Z)) was analysed. The strongest correlation was between FFM (DEXA) and height2/‘whole-body’Z (Zw) (r 0.97 for the combined sexes, standard error of estimate (SEE) 2.72 kg). Separate prediction equations were found to be necessary for males and females when estimating FFM from BIA measurement of the arm (for men, r 0.93, SEE 1.98 kg; for women, r 0.75, SEE 2.87 kg). Muscle mass derived from 24 h creatinine excretion showed weak correlation with FFM (DEXA) (r 0.57, P = 0.03) and no correlation with FFM (SFA). FFM (SFA) correlated well with both FFM (DEXA) (r 0.96, SEE = 3.12 kg) and with height2/Zw (r 0.92, SEE 4.52 kg). Measurement of the impedance of the arm offers a simple method of assessing the composition of the whole body in normal individuals, and it appears comparable with other methods of assessment.

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