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Background/Objectives: Weight loss is frequently seen in advanced cancer. Bioelectrical impedance spectroscopy (BIS) is a convenient method for estimating body composition. We examined in a prospective, comparative study if BIS could accurately estimate fat-free mass (FFM) in cancer patients compared to dual-energy X-ray absorptiometry (DXA). Subjects/Methods: The study was based on 132 consecutive incurable cancer patients with solid tumours in a University hospital outpatient clinic. Comparison of FFM from DXA and BIS with standard and revised equations. Bland-Altman plots, t-tests and linear regression analysis were used to evaluate agreement and differences between methods. Results: BIS significantly underestimated mean FFM with 7.6 [+ or -] 4.7kg compared to DXA (P Conclusions: BIS by standard equations grossly underestimates FFM compared to DXA in cancer patients. This bias is related to weight loss, malnutrition and systemic inflammation. Revised equations improved FFM estimates, but with large individual variation. Thus, BIS with standard equations is not suitable to estimate FFM in patients with cachexia, inflammation and malnutrition. doi:10.1038/ejcn.2008.35; published online 14 May 2008 Keywords: bioelectrical impedance; spectroscopy; dual-energy X-ray absorptiometry; body composition; cancer, Introduction Patients with progressive cancer often suffer from weight loss (Barber et al., 1999; Bosaeus et al., 2001). Although the mechanisms underlying this cachexia are not yet fully understood, systemic [...]

The activation of protein synthesis and the inhibition of protein breakdown in arm and leg tissues correlates with high levels of plasma amino acids. The activation of protein synthesis and attenuation of amino acid breakdown enhanced protein balance in the muscles even under constant levels of plasma insulin, insulin-like growth factor-1 and nonprotein substrate concentrations. The concentrations of intracellular amino acids and the transportation of amino acids across the cell membranes are also associated with the activation of protein synthesis.

The euglycenic clamp model aids in examining the influence of insulin on synthesis and breakdown of protein in peripheral tissues of normal men. A postabsorptive enhancement in plasma insulin reduces degeneration of proteins in peripheral tissues of unstressed and normal healthy men to improve the total balance of protein. The rate of breakdown of nonmyofibrillar proteins in peripheral tissues is selectively reduced by insulin.

Background : The purpose of this study was to evaluate to what extent self-reported health related quality of life (HRQL), assessed by the Swedish standard version of the Medical Outcome Study Short-Form 36 (SF-36), is related to measured exercise capacity and metabolic efficiency in a cohort of healthy subjects from the Gothenburg area of Sweden. Material and methods : Individuals were invited to take part in the evaluation where HRQL was compared with the maximal power output expressed in Watts assessed during a standardized treadmill test with incremental work loads. Whole body respiratory gas exchanges (CO2/O2) were simultaneously measured. Estimate of metabolic efficiency was derived from oxygen uptake per Watt produced (ml O2/min/W) near maximal work. Results : The health status profile in the current population largely agreed with normative data from an age- and gender-matched reference group, although some measured scores were slightly better than reference scores. Males and females had a similar relationship between energy cost (ml O2/min) for production of maximal work (W), while the regressions for maximal exercise power and age were significantly different between males and females (p < 0.01). The overall metabolic efficiency was the same in individuals between 40 and 74 years of age (10.4 ± 0.07 ml O2/min/Watt). Maximal exercise power was only related to the SF-36 subscale physical functioning (PF), but unrelated to other physical subscales such as role limitations due to physical problems, good general health and vitality. There was also a discrepancy between measured maximal power and PF in many subjects, particularly in males who experienced either intact or severely reduced PF. Conclusions : Our results demonstrate that simultaneous measurements of self-reported and objective measures of PF should add a more integrated view for evaluation of therapeutic effectiveness, since the overall correlation was poor between objective and subjective scores among individuals. [ABSTRACT FROM AUTHOR]