Concurrent and Construct Validity of Methods to Estimate Fat-Free Mass in Children, Adolescents, and Young Adults

INTRODUCTION: Indirect methodologies are available to estimate fat-free mass (FFM) as a skeletal muscle mass surrogate in field settings at low cost. However, there is a lack of knowledge related with the FMM estimations variability introduced by the available methods and its correlations with performance constructs. The association between repeated measures of FFM by different methodologies and strength tests must provide a valuable construct validity analysis, which allows us to select the best method to assess the functional body composition. PURPOSE: To analyze validity and agreement between laboratory and field methods to estimate FFM in children, adolescents, and young adults, and their relationships with strength. METHODS: We studied a dataset of participants aged 6-21y (531 assessments, 287 boys). FFM was evaluated by isotope dilution method (REF), dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) and anthropometry (ANT). Isometric strength was assessed by limb dynamometry and dynamic strength as sprinting and jumping. Concurrent validity was analyzed by differences between methods and concordance correlation coefficient (CCC), agreement by Bland-Altman analysis, and construct validity by individual associations. RESULTS: FFM from ANT had the lowest bias in girls (-2.33±4.41kg, P≤0.0001) and from BIA in boys (-1.79±4.51kg, P≤0.0001). The best CCC was found for FFM-BIA (girls, 0.764; boys, 0.926). The highest correlation with constructs was found for handgrip and FFM-BIA in girls (r=-0.743) and FFM-REF in boys (r=0.812; both P≤0.001). CONCLUSION: Our results showed BIA was the best method to estimate FFM. Nonetheless, there was not a single method which correlated the best with all strength constructs. The low coordinative requirement of isometric strength test could be one of the reasons to find a better correlation with FFM than explosive dynamic tests, and this leads us to speculate that isometric strength is more dependent of body composition than dynamic tests. These findings needed to be refuted with additional constructs

Clustering of photometric luminous red galaxies I : Growth of Structure and Baryon Acoustic Feature

The possibility of measuring redshift space (RSD) distortions using photometric data have been recently highlighted. This effect complements and significantly alters the detectability of baryon acoustic oscillations (BAO) in photometric surveys. In this paper we present measurements of the angular correlation function of luminous red galaxies (LRGs) in the photometric catalog of the final data release (DR7) of the Sloan Digital Sky Survey II (SDSS). The sample compromise ~ 1.5 x 10^6 LRGs distributed in 0.45 < z < 0.65, with a characteristic photometric error of ~ 0.05. Our measured correlation centered at z=0.55 is in very good agreement with predictions from standard LCDM in a broad range of angular scales, $0.5^\circ < \theta < 6^\circ$. We find that the growth of structure can indeed be robustly measured, with errors matching expectations. The velocity growth rate is recovered as $f \sigma_8 = 0.53 \pm 0.42$ when no prior is imposed on the growth factor and the background geometry follows a LCDM model with WMAP7+SNIa priors. This is compatible with the corresponding General Relativity (GR) prediction $f \sigma_8 = 0.45$ for our fiducial cosmology. If we adopt a parametrization such that $f=\Omega ^\gamma_m(z)$, with $\gamma \approx 0.55$ in GR, and combine our $f\sigma_8$ measurement with the corresponding ones from spectroscopic LRGs at lower redshifts we obtain $\gamma=0.54 \pm 0.17$. In addition we find evidence for the presence of the baryon acoustic feature matching the amplitude, location and shape of LCDM predictions. The photometric BAO feature is detected with 98 % confidence level at z=0.55.Comment: 16 pages, 19 figures, minor changes to text to match accepted version by MNRA

Cancer, Senescence, and Aging: Translation from Basic Research to Clinics

2 páginas.Unravelling the molecular basis of malignancy is a challenging process of great priority, as cancer rates are increasing worldwide and because certain cancer types are still incurable. The urgent need for novel treatment modalities based upon recent discoveries at the genetic and epigenetic level necessitates a strong collaboration between researchers and clinicians to work toward a common aim: the control of the carcinogenic process in order to ultimately achieve a 100% cure rate.Peer reviewe

Functional relevance of a non-synonymous substitution in the CD5 gene (V471A) targeted for positive selection in East Asian populations

1 página.-- Póster presentado en el 5º European Workshop on Immune-Mediated Inflammatory Diseases celebrado en Sitges (Barcelona) del 1 al 3 de Diciembre de 2010.Peer reviewe

NAMPT as a Dedifferentiation-Inducer Gene: NAD+ as Core Axis for Glioma Cancer Stem-Like Cells Maintenance

Glioma Cancer Stem-Like Cells (GSCs) are a small subset of CD133+ cells with self-renewal properties and capable of initiating new tumors contributing to Glioma progression, maintenance, hierarchy, and complexity. GSCs are highly resistant to chemo and radiotherapy. These cells are believed to be responsible for tumor relapses and patients' fatal outcome after developing a recurrent Glioblastoma (GBM) or High Grade Glioma (HGG). GSCs are cells under replicative stress with high demands on NAD+ supply to repair DNA, maintain self-renewal capacity and to induce tumor plasticity. NAD+ feeds Poly-ADP polymerases (PARP) and NAD+-dependent deacetylases (SIRTUINS) contributing to GSC phenotype. This energetic core axis is mainly controlled by the rate-limiting enzyme nicotinamide phosphoribosyltransferase (NAMPT), an important oncogene contributing to tumor dedifferentiation. Targeting GSCs depicts a new frontier in Glioma therapy; hence NAMPT could represent a key regulator for GSCs maintenance. Its inhibition may attenuate GSCs properties by decreasing NAD+ supply, consequently contributing to a better outcome together with current therapies for Glioma control

Continuous intraocular pressure monitoring in patients with obstructive sleep apnea syndrome using a contact lens sensor

Purpose To analyse nocturnal intraocular pressure (IOP) fluctuations in patients with obstructive sleep apnea syndrome (OSAS) using a contact lens sensor (CLS) and to identify associations between the OSAS parameters determined by polysomnographic study (PSG) and IOP changes. Method Prospective, observational study. Twenty participants suspected of having OSAS were recruited. During PSG study, IOP was monitored using a CLS placed in the eye of the patient. The patients were classified according to the apnea-hypopnea index (AHI) in two categories, severe (>30) or mild/moderate (<30) OSAS. We evaluated several parameters determined by the IOP curves, including nocturnal elevations (acrophase) and plateau times in acrophase (PTs) defined by mathematical and visual methods. Results The IOP curves exhibited a nocturnal acrophase followed by PTs of varying extents at which the IOP remained higher than daytime measurement with small variations. We found significant differences in the length of the PTs in patients with severe OSAS compared to those with mild/moderate disease (P = 0.032/P = 0.028). We found a positive correlation between PTs and OSAS severity measured by the total number of apneic events (r = 0.681/ 0.751 P = 0.004/0.001) and AHI (r = 0.674/0.710, P = 0.004/0.002). Respiratory-related arousal and oxygen saturation also were associated significantly with the IOP PT length. Conclusions Periods of nocturnal IOP elevation lasted longer in severe OSAS patients than those with mild/moderate OSAS and correlate with the severity of the disease. The length of the nocturnal PT is also associated to respiratory parameters altered in patients with OSAS

Clustering of Photometric Luminous Red Galaxies II: Cosmological Implications from the Baryon Acoustic Scale

A new determination of the sound horizon scale in angular coordinates is presented. It makes use of ~ 0.6 x 10^6 Luminous Red Galaxies, selected from the Sloan Digital Sky Survey imaging data, with photometric redshifts. The analysis covers a redshift interval that goes from z=0.5 to z=0.6. We find evidence of the Baryon Acoustic Oscillations (BAO) signal at the ~ 2.3 sigma confidence level, with a value of theta_{BAO} (z=0.55) = (3.90 \pm 0.38) degrees, including systematic errors. To our understanding, this is the first direct measurement of the angular BAO scale in the galaxy distribution, and it is in agreement with previous BAO measurements. We also show how radial determinations of the BAO scale can break the degeneracy in the measurement of cosmological parameters when they are combined with BAO angular measurements. The result is also in good agreement with the WMAP7 best-fit cosmology. We obtain a value of w_0 = -1.03 \pm 0.16 for the equation of state parameter of the dark energy, Omega_M = 0.26 \pm 0.04 for the matter density, when the other parameters are fixed. We have also tested the sensitivity of current BAO measurements to a time varying dark energy equation of state, finding w_a = 0.06 \pm 0.22 if we fix all the other parameters to the WMAP7 best-fit cosmology.Comment: 7 pages, 7 figures, Accepted for publication to MNRA

About the self-dual Chern-Simons system and Toda field theories on the noncommutative plane

The relation of the noncommutative self-dual Chern-Simons (NCSDCS) system to the noncommutative generalizations of Toda and of affine Toda field theories is investigated more deeply. This paper continues the programme initiated in $JHEP {\bf 10} (2005) 071$, where it was presented how it is possible to define Toda field theories through second order differential equation systems starting from the NCSDCS system. Here we show that using the connection of the NCSDCS to the noncommutative chiral model, exact solutions of the Toda field theories can be also constructed by means of the noncommutative extension of the uniton method proposed in $JHEP {\bf 0408} (2004) 054$ by Ki-Myeong Lee. Particularly some specific solutions of the nc Liouville model are explicit constructed.Comment: 24 page