scholarly journals Metabolically active portion of fat-free mass: a cellular body composition level modeling analysis

2007 ◽  
Vol 292 (1) ◽  
pp. E49-E53 ◽  
Author(s):  
ZiMian Wang ◽  
Stanley Heshka ◽  
Jack Wang ◽  
Dympna Gallagher ◽  
Paul Deurenberg ◽  
...  
Keyword(s):  
Water Distribution ◽  
Cell Mass ◽  
Extracellular Fluid ◽  
Multiple Linear Regression Model ◽  
Resting Energy Expenditure ◽  
Cellular Level ◽  
Fat Free Mass ◽  
Whole Body ◽  
Total Body

The proportion of fat-free mass (FFM) as body cell mass (BCM) is highly related to whole body resting energy expenditure. However, the magnitude of BCM/FFM may have been underestimated in previous studies. This is because Moore's equation [BCM (kg) = 0.00833 × total body potassium (in mmol)], which was used to predict BCM, underestimates BCM by ∼11%. The aims of the present study were to develop a theoretical BCM/FFM model at the cellular level and to explore the influences of sex, age, and adiposity on the BCM/FFM. Subjects were 112 adults who had the following measurements: total body water by2H2O or3H2O dilution; extracellular water by NaBr dilution; total body nitrogen by in vivo neutron activation analysis; and bone mineral by dual-energy X-ray absorptiometry. FFM was calculated using a multicomponent model and BCM as the difference between FFM and the sum of extracellular fluid and solids. The developed theoretical model revealed that the proportion of BCM to FFM is mainly determined by water distribution (i.e., E/I, the ratio of extracellular to intracellular water). A significant correlation ( r = 0.90, P < 0.001) was present between measured and model-predicted BCM/FFM for all subjects pooled. Measured BCM/FFM [mean (SD)] was 0.584 ± 0.041 and 0.529 ± 0.041 for adult men and women ( P < 0.001), respectively. A multiple linear regression model showed that there are independent significant associations of sex, age, and fat mass with BCM/FFM.

Body cell mass: model development and validation at the cellular level of body composition

2004 ◽  
Vol 286 (1) ◽  
pp. E123-E128 ◽  
Author(s):  
ZiMian Wang ◽  
Marie-Pierre St-Onge ◽  
Beatriz Lecumberri ◽  
F. Xavier Pi-Sunyer ◽  
Stanley Heshka ◽  
...  
Keyword(s):  
Body Composition ◽  
Reference Data ◽  
Cell Mass ◽  
Cellular Level ◽  
Whole Body ◽  
Body Cell Mass ◽  
Prediction Formula ◽  
Body Cell ◽  
Total Body

Existing models to estimate the metabolically active body cell mass (BCM) component in vivo remain incompletely developed. The classic Moore model is based on an assumed BCM potassium content of 120 mmol/kg. Our objectives were to develop an improved total body potassium (TBK)-independent BCM prediction model on the basis of an earlier model (Cohn SH, Vaswani AN, Yasumura S, Yuen K, and Ellis KJ. J Lab Clin Med 105: 305-311, 1985), to apply this improved model in subjects to explore the sex and age dependence of the TBK/BCM ratio, to develop a new TBK/BCM model on the basis of physiological associations between TBK and total body water (TBW) at the cellular level of body composition, and to fit this new model with available reference data. Subjects were 112 healthy adults who had the following components measured: TBW by 2H2O or 3H2O, extracellular water by NaBr, total body nitrogen by in vivo neutron activation, bone mineral by dual-energy X-ray absorptiometry, and TBK by whole body counting. Human reference data were collected from earlier published reports. The improved Cohn model-derived TBK/BCM ratio was (mean ± SD) 109.0 ± 10.9 mmol/kg and was not significantly related to sex and age. A simplified version of the new TBK-TBW model provided a TBK/BCM ratio almost identical (109.1 mmol/kg) to that derived by the improved Cohn model. The TBK-BCM prediction formula derived from the improved and new models [BCM (kg) = 1/109 × TBK (mmol); or BCM = 0.0092 × TBK] gives BCM estimates ∼11% higher than the classic Moore model (BCM = 0.0083 × TBK) formulated on rough tissue composition estimates. The present analyses provide a physiologically based, improved, and validated TBK-BCM prediction formula that should prove useful in body composition and metabolism research.

scholarly journals Smaller organ mass with greater age, except for heart

2009 ◽  
Vol 106 (6) ◽  
pp. 1780-1784 ◽  
Author(s):  
Qing He ◽  
Stanley Heshka ◽  
Jeanine Albu ◽  
Lawrence Boxt ◽  
Norman Krasnow ◽  
...  
Keyword(s):  
African Americans ◽  
The Elderly ◽  
Left Ventricular ◽  
Fat Free Mass ◽  
Whole Body ◽  
Organ Mass ◽  
Total Body ◽  
Age Range ◽  
Negative Relationships

Autopsy/cadaver data indicate that many organs and tissues are smaller in the elderly compared with young adults; however, in vivo data are lacking. The aim of this study was to determine whether the mass of specific high-metabolic-rate organs is different with increasing age, using MRI. Seventy-five healthy women (41 African-Americans and 34 Caucasians, age range 19–88 yr) and 36 men (8 African-Americans and 28 Caucasians, age range 19–84 yr) were studied. MRI-derived in vivo measures of brain, heart, kidneys, liver, and spleen were acquired. Left ventricular mass (LVM) was measured by either echocardiography or cardiac gated MRI. Total body fat mass and fat-free mass (FFM) were measured with a whole body dual-energy X-ray absorptiometry (DXA) scanner. Multiple regression analysis was used to investigate the association between the organ mass and age after adjustment for weight and height (or DXA measures of FFM), race, sex, and interactions among these variable. No statistically significant interaction was found among age, sex, and race in any regression model. Significant negative relationships between organ mass and age were found for brain ( P < 0.0001), kidneys ( P = 0.01), liver ( P = 0.001), and spleen ( P < 0.0001). A positive relationship between LVM and age was found after adjustment for FFM ( P = 0.037). These findings demonstrate that age has a significant effect on brain, kidneys, liver, spleen, and heart mass. The age effect was independent of race and sex.

Hydration of fat-free body in protein-depleted patients

1985 ◽  
Vol 249 (2) ◽  
pp. E227-E233 ◽  
Author(s):  
A. H. Beddoe ◽  
S. J. Streat ◽  
G. L. Hill
Keyword(s):  
Cell Mass ◽  
Protein A ◽  
Extracellular Fluid ◽  
The Body ◽  
Fat Free Mass ◽  
Body Protein ◽  
Mean Values ◽  
Free Body ◽  
Fluid Compartments ◽  
Total Body

It is widely believed that increased hydration of the fat-free body accompanies most major disease processes as a result of contraction of the body cell mass and expansion of the extracellular fluid. Measurements of total body water (TBW) and total body nitrogen in 68 normal volunteers and 95 surgical ward patients presenting for intravenous nutrition have been used to derive ratios of TBW to fat-free mass (TBW:FFM) and protein indices (PI), where PI is defined as the ratio of measured total body protein to predicted TBP. Mean values of PI were 1.009 +/- 0.116 (SD) and 0.783 +/- 0.152 in the normal and patient groups, respectively, corresponding to mean TBW:FFM ratios of 0.719 +/- 0.016 and 0.741 +/- 0.029. However, 48 patients had normal TBW:FFM despite having lost 15% of body protein. A theoretical model of body composition changes in catabolic illness is presented, which is in accord with the patient data, demonstrating that TBW:FFM does not necessarily increase in catabolic illness and that the ratio masks underlying shifts in body fluid compartments.

Magnitude and variation of fat-free mass density: a cellular-level body composition modeling study

2003 ◽  
Vol 284 (2) ◽  
pp. E267-E273 ◽  
Author(s):  
Zimian Wang ◽  
Stanley Heshka ◽  
Jack Wang ◽  
Lucian Wielopolski ◽  
Steven B. Heymsfield
Keyword(s):  
Body Composition ◽  
Mass Density ◽  
Age Groups ◽  
Experimental Studies ◽  
Compartment Model ◽  
Cellular Level ◽  
Fat Free Mass ◽  
Total Body

The mean density of fat-free mass (FFM) is remarkably stable at 1.10 g/cm3 in healthy adult humans, and this stability is a cornerstone of the widely applied densitometry-based two-compartment model for estimating total body fat. At present, the usual means of exploring FFM density is by in vitro or in vivo experimental studies. The purpose of the present investigation was to develop a cellular-level body composition model that includes seven factors that determine FFM density. The model, when applied with available empirical coefficients, predicted an FFM density similar to that observed in vivo. An analysis of the seven model components indicates that the ratio of extracellular solids to total body water is a major determinant of individual variation in FFM density. The difference in FFM density across sex, race, and age groups was examined with the developed model. The present study thus provides a conceptual framework for the systematic study of FFM density in humans.

In Vivo Whole-Body Resting Energy Expenditure and Insulin Action in Human Malignant Hyperthermia 

2000 ◽  
Vol 93 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Daniel Freymond ◽  
Olivier Dériaz ◽  
Philippe Frascarolo ◽  
Sebastian Reiz ◽  
Eric Jéquier ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Malignant Hyperthermia ◽  
Insulin Action ◽  
Resting Energy Expenditure ◽  
Fat Free Mass ◽  
Whole Body ◽  
Energy Turnover ◽  
Age And Gender ◽  
And Gender

Background Malignant hyperthermia (MH) is a pharmacogenetic disease triggered by volatile anesthetics or succinylcholine. The disorder is heterogenetic and caused by abnormal calcium regulation within skeletal muscle cells. No clear metabolic differences have been found in MH-susceptible (MHS) persons in vivo while not having MH episodes, but some reported signs suggest that insulin action and energy turnover might be altered in muscle of MHS persons. Methods In fasting and insulin-stimulated conditions, using the glucose clamp technique and indirect calorimetry, we assessed in vivo resting energy expenditure (REE) and nutrient utilization rates in 10 MHS, 5 MH-equivocal (MHE) and 10 MH-negative (MHN) persons from 14 families. With a model using the persons' fat-free mass, fat mass, age, and gender, we calculated their predicted REE and compared it with measured REE in 10 MHS and 10 MHN persons (measured - predicted = residual REE). Results In vivo measured REE and glucose disposal rates were similar in 10 MHS and 10 MHN persons. Only during insulin stimulation was residual REE greater in MHS persons (6.4%; P = 0. 013). Conclusions In vivo insulin action is unimpaired in MHS persons. Although the absolute values of whole-body REE are the same in MHS and MHN persons, the part of REE independent of the determinants fat-free mass, fat mass, age, and gender is moderately greater in MHS than in MHN persons during insulin exposure. This suggests that MH susceptibility might influence insulin-stimulated energy turnover in muscle.

The Measurement of Total Body Potassium in Patients on Peritoneal Dialysis

2001 ◽  
Vol 21 (3_suppl) ◽  
pp. 163-167 ◽  
Author(s):  
Graham Woodrow ◽  
Brian Oldroyd ◽  
Antony Wright ◽  
W. Andrew Coward ◽  
John H. Turney ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Deuterium Oxide ◽  
Cell Mass ◽  
Fat Free Mass ◽  
Whole Body ◽  
Body Cell Mass ◽  
Total Body Potassium ◽  
Noninvasive Technique ◽  
Body Cell ◽  
Total Body

♦ Objectives To assess the validity of measuring total body potassium (TBK) to estimate fat-free mass (FFM) and body cell mass (BCM) in patients on peritoneal dialysis (PD). ♦ Methods We studied 29 patients on PD (14 men, 15 women) and 30 controls (15 men, 15 women). We calculated TBK by using a whole-body counter to measure 1.46 MeV gamma-ray emissions from naturally occurring 40K. We measured total body water (TBW) by deuterium oxide dilution, and extracellular water (ECW) from bromide dilution. These measurements allowed us to estimate intracellular water (ICW), fat-free mass dilution (FFMDilution), and body cell mass dilution (BCMDilution). ♦ Results The FFMTBK in male PD patients (55.7 ± 7.0 kg) did not differ from that in male controls (57.0 ± 10.9 kg). The FFMTBK in female PD patients (38.4 ± 6.8 kg) was less than that in female controls (44.7 ± 4.5, p < 0.01). The FFMDilution did not differ from the FFMTBK. Correlation of FFMTBK and FFMDilution was r = 0.90, p < 0.0001 for all subjects; r = 0.90, p < 0.0001 for PD patients; and r = 0.90, p < 0.0001 for controls. Bland–Altman comparison of FFMDilution with FFMTBK in individuals showed bias 0.6 kg, range –8.5 kg to 9.7 kg for the whole group; bias 1.4 kg, range –7.9 kg to 10.7 kg for PD patients; and bias –0.2 kg, range –9.0 kg to 8.6 kg for controls. The BCMTBK in male PD patients (30.1 ± 4.5 kg) did not differ from that in male controls (31.9 ± 6.2 kg). The BCMTBK in female PD patients (19.0 ± 4.4 kg) was less than that in female controls (23.1 ± 2.9 kg, p < 0.01). The BCMDilution results did not differ from those for the BCMTBK. Correlation of BCMTBK and BCMDilution was r = 0.90, p < 0.0001 for all subjects; r = 0.87, p < 0.0001 for PD patients; and r = 0.93, p < 0.0001 for controls. Bland–Altman comparison of BCMDilution with BCMTBK in individuals showed bias 0.1 kg, range –5.9 kg to 6.1 kg for the whole group; bias 0.0 kg, range –6.9 kg to 6.9 kg for PD patients; and bias 0.1 kg, range –5.0 kg to 5.2 kg for controls. The [K+]ICW did not differ between PD patients and controls (148.0 ± 25.1 mmol/L vs 148.1 ± 14.3 mmol/L, p = nonsignificant). ♦ Conclusions Total body potassium is a valid, noninvasive technique for measuring FFM and BCM in PD patients. In our PD patient group, depletion of FFM and BCM as compared with controls was identified in the women but not in the men.

Use of Continuous Blood Volume Monitoring to Detect Inadequately High Dry Weight

1996 ◽  
Vol 19 (7) ◽  
pp. 411-414 ◽  
Author(s):  
F. Lopot ◽  
P. Kotyk ◽  
J. Bláha ◽  
J. Forejt
Keyword(s):  
Blood Volume ◽  
Vena Cava ◽  
Extracellular Fluid ◽  
Dry Weight ◽  
Whole Body ◽  
The Status ◽  
Varying Length ◽  
Group 3 ◽  
Group 2 ◽  
Total Body

A continuous blood volume monitoring (CBVM) device (Inline Diagnostics, Riverdale, USA) was used to study response to prescribed ultrafiltration during haemodialysis (HD) in 66 stabilised HD patients. Fifty percent of patients showed the expected linear decrease in BV right from the beginning of HD (group 1), 32% exhibited no decrease at all (group 2), while eighteen percent formed the transient group 3 which showed a plateau of varying length after which a decrease occurred. The correct setting of dry weight was verified through evaluation of the ratio of extracellular fluid volume to total body water (VEC/TBW) in 26 patients by means of whole body multifrequency impedometry MFI (Xitron Tech., San Diego, USA) and through measurement of the Vena Cava Inferior diameter (VCID) pre and post HD (in 6 and 5 patients from groups 1 and 3 and from group 2, respectively). The mean VEC/TBW in groups 1 and 3 was 0.56 pre and 0.51 post HD as compared to 0.583 and 0.551 in group 2. VCID decreased on average by 14.1% in groups 1 and 3 but remained stable in group 2. Both findings thus confirmed inadequately high estimation of dry weight. Since CBVM is extremely easy to perform it can be used as a method of choice in detecting inadequately high prescribed dry weight. The status of the cardiovascular system must always be considered before final judgement is made.

Magnitude and variation of ratio of total body potassium to fat-free mass: a cellular level modeling study

2001 ◽  
Vol 281 (1) ◽  
pp. E1-E7 ◽  
Author(s):  
Zimian Wang ◽  
F. Xavier Pi-Sunyer ◽  
Donald P. Kotler ◽  
Jack Wang ◽  
Richard N. Pierson ◽  
...  
Keyword(s):  
Body Fat ◽  
Essential Element ◽  
Physiological Model ◽  
Cellular Level ◽  
Fat Free Mass ◽  
Total Body Potassium ◽  
Fluid Compartment ◽  
Total Body Fat ◽  
Total Body ◽  
Living Organisms

Potassium is an essential element of living organisms that is found almost exclusively in the intracellular fluid compartment. The assumed constant ratio of total body potassium (TBK) to fat-free mass (FFM) is a cornerstone of the TBK method of estimating total body fat. Although the TBK-to-FFM (TBK/FFM) ratio has been assumed constant, a large range of individual and group values is recognized. The purpose of the present study was to undertake a comprehensive analysis of biological factors that cause variation in the TBK/FFM ratio. A theoretical TBK/FFM model was developed on the cellular body composition level. This physiological model includes six factors that combine to produce the observed TBK/FFM ratio. The ratio magnitude and range, as well as the differences in the TBK/FFM ratio between men and women and variation with growth, were examined with the proposed model. The ratio of extracellular water to intracellular water ( E/I) is the major factor leading to between-individual variation in the TBK/FFM ratio. The present study provides a conceptual framework for examining the separate TBK/FFM determinants and suggests important limitations of the TBK/FFM method used in estimating total body fat in humans and other mammals.

scholarly journals Follow-up of GK rats during prediabetes highlights increased insulin action and fat deposition despite low insulin secretion

2008 ◽  
Vol 294 (1) ◽  
pp. E168-E175 ◽  
Author(s):  
Jamileh Movassat ◽  
Danièle Bailbé ◽  
Cécile Lubrano-Berthelier ◽  
Françoise Picarel-Blanchot ◽  
Eric Bertin ◽  
...  
Keyword(s):  
Body Composition ◽  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Cell Function ◽  
Cell Mass ◽  
The Body ◽  
Whole Body ◽  
Β Cell ◽  
Gk Rats

The adult Goto-Kakizaki (GK) rat is characterized by impaired glucose-induced insulin secretion in vivo and in vitro, decreased β-cell mass, decreased insulin sensitivity in the liver, and moderate insulin resistance in muscles and adipose tissue. GK rats do not exhibit basal hyperglycemia during the first 3 wk after birth and therefore could be considered prediabetic during this period. Our aim was to identify the initial pathophysiological changes occurring during the prediabetes period in this model of type 2 diabetes (T2DM). To address this, we investigated β-cell function, insulin sensitivity, and body composition in normoglycemic prediabetic GK rats. Our results revealed that the in vivo secretory response of GK β-cells to glucose is markedly reduced and the whole body insulin sensitivity is increased in the prediabetic GK rats in vivo. Moreover, the body composition of suckling GK rats is altered compared with age-matched Wistar rats, with an increase of the number of adipocytes before weaning despite a decreased body weight and lean mass in the GK rats. None of these changes appeared to be due to the postnatal nutritional environment of GK pups as demonstrated by cross-fostering GK pups with nondiabetic Wistar dams. In conclusion, in the GK model of T2DM, β-cell dysfunction associated with increased insulin sensitivity and the alteration of body composition are proximal events that might contribute to the establishment of overt diabetes in adult GK rats.

Letters to the Editor

PEDIATRICS ◽  
1968 ◽  
Vol 41 (6) ◽  
pp. 1147-1148
Author(s):  
John C. Sinclair
Keyword(s):  
Oxygen Consumption ◽  
Cell Mass ◽  
Extracellular Fluid ◽  
Chemical Constituent ◽  
Metabolic Function ◽  
Total Body Potassium ◽  
Letters To The Editor ◽  
Relative Growth ◽  
Total Body

Professor Burmeister, in dealing with problems of relative growth, uses equations of the form Y = a Xh, as proposed by Huxley. Values for the exponent b, in equations of this form, indicate the rate of accretion of the part (organ, chemical constituent, body compartment, metabolic function) in relation to the whole. Values for b of less than one indicate a relatively lesser rate of accretion of the part See Images in the PDF File e.g., our exponent for extracellular fluid, b = 0.80 (Table II of Burmeister's reference 5); values of greater than one indicate a relatively greater rate of accretion of the part–e.g., Burmeister's exponents for total body potassium, 1.09, and for cell mass, 1.11, and ours for resting oxygen consumption, 1.22, and for fat, 2.18 (Table II of Burmeister's reference 5).

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