Body composition in older community-dwelling adults with hip fracture: portable field methods validated by dual-energy X-ray absorptiometry

Ageing is associated with weight loss and subsequently poor health outcomes. The present study assessed agreement between two field methods, bioelectrical impedance spectroscopy (BIS) and corrected arm muscle area (CAMA) for assessment of body composition against dual-energy X-ray absorptiometry (DXA), the reference technique. Agreement between two predictive equations estimating skeletal muscle mass (SMM) from BIS against SMM from DXA was also determined. Assessments occurred at baseline < 14 d post-surgery (n 79), and at 6 months (6M; n 75) and 12 months (12M; n 63) in community-living older adults after surgical treatment for hip fracture. The 95 % limits of agreement (LOA) between BIS and DXA, CAMA and DXA and the equations and DXA were assessed using Bland–Altman analyses. Mean bias and LOA for fat-free mass (FFM) between BIS and DXA were: baseline, 0·7 ( − 10·9, 12·4) kg; 6M, − 0·5 ( − 20·7, 19·8) kg; 12M, 0·1 ( − 8·7, 8·9) kg and for SMM between CAMA and DXA were: baseline, 0·3 ( − 11·7, 12·3) kg; 6M, 1·3 ( − 4·5, 7·1) kg; 12M, 0·9 ( − 5·4, 7·2) kg. Equivalent data for predictive equations against DXA were: equation 1: baseline, 15·1 ( − 9·5, 20·6) kg; 6M, 17·1 ( − 12·0, 22·2) kg; 12M, 17·5 ( − 13·0, 22·0) kg; equation 2: baseline, 12·6 ( − 7·3, 19·9) kg; 6M, 14·4 ( − 9·7, 19·1) kg; 12M, 14·8 ( − 10·7, 18·9) kg. Proportional bias (BIS: β = − 0·337, P< 0·001; CAMA: β = − 0·294, P< 0·001) was present at baseline but not at 6M or 12M. Clinicians should be cautious in using these field methods to predict FFM and SMM, particularly in the acute care setting. New predictive equations would be beneficial.This research was supported by the National Health and Medical Research Council (NHMRC), Australia

Factors involved in the handling of iron by the reticulo-endothelial system

A thesis presented for the degree of Doctor of Philosophy in Medicine of the University of the Witwatersrand, Johannesburg 1972For centuries iron was regarded as a source of health and vigour, and it has been known for at least 200 years that it is a component of blood and effective in the treatment of chlorosis. However, its metabolism remained largely a mystery until the advent of radioactive iron isotopes in 1938. Since then most of the major pathways of this metal into, through and out of the body have been elucidated. In addition the functions which it subserves have been partially characterized.IT201

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A predictive phenomenological tool at small Bjorken-x

We present the results from global fits of inclusive DIS experimental data using the Balitsky-Kovchegov equation with running coupling.Comment: 5 pages, 2 figures, prepared for the Proceedings of 'Hot Quarks 2010

Iron bioavailability in two commercial cultivars of wheat: a comparison between wholegrain and white flour and the effects of nicotianamine and 2'-deoxymugineic acid on iron uptake into Caco-2 cells

Iron bioavailability in unleavened white and wholegrain bread made from two commercial wheat varieties was assessed by measuring ferritin production in Caco-2 cells. The breads were subjected to simulated gastrointestinal digestion and the digests applied to the Caco-2 cells. Although Riband grain contained a lower iron concentration than Rialto, iron bioavailability was higher. No iron was taken up by the cells from white bread made from Rialto flour or from wholegrain bread from either variety, but Riband white bread produced a small ferritin response. The results probably relate to differences in phytate content of the breads, although iron in soluble monoferric phytate was demonstrated to be bioavailable in the cell model. Nicotianamine, an iron chelator in plants involved in iron transport, was a more potent enhancer of iron uptake into Caco-2 cells than ascorbic acid or 2'-deoxymugineic acid, another metal chelator present in plants

Two-body quantum mechanical problem on spheres

The quantum mechanical two-body problem with a central interaction on the sphere ${\bf S}^{n}$ is considered. Using recent results in representation theory an ordinary differential equation for some energy levels is found. For several interactive potentials these energy levels are calculated in explicit form.Comment: 41 pages, no figures, typos corrected; appendix D was adde

Error bounds for the large-argument asymptotic expansions of the Hankel and Bessel functions

In this paper, we reconsider the large-argument asymptotic expansions of the Hankel, Bessel and modified Bessel functions and their derivatives. New integral representations for the remainder terms of these asymptotic expansions are found and used to obtain sharp and realistic error bounds. We also give re-expansions for these remainder terms and provide their error estimates. A detailed discussion on the sharpness of our error bounds and their relation to other results in the literature is given. The techniques used in this paper should also generalize to asymptotic expansions which arise from an application of the method of steepest descents.Comment: 32 pages, 2 figures, accepted for publication in Acta Applicandae Mathematica

UV activation of polymeric high aspect ratio microstructures: Ramifications in antibody surface loading for circulating tumor cell selection

The need to activate thermoplastic surfaces using robust and efficient methods has been driven by the fact that replication techniques can be used to produce microfluidic devices in a high production mode and at low cost, making polymer microfluidics invaluable for in vitro diagnostics, such as circulating tumor cell (CTC) analysis, where device disposability is critical to mitigate artifacts associated with sample carryover. Modifying the surface chemistry of thermoplastic devices through activation techniques can be used to increase the wettability of the surface or to produce functional scaffolds to allow for the covalent attachment of biologics, such as antibodies for CTC recognition. Extensive surface characterization tools were used to investigate UV activation of various surfaces to produce uniform and high surface coverage of functional groups, such as carboxylic acids in microchannels of different aspect ratios. We found that the efficiency of the UV activation process is highly dependent on the microchannel aspect ratio and the identity of the thermoplastic substrate. Colorimetric assays and fluorescence imaging of UV-activated microchannels following EDC/NHS coupling of Cy3-labeled oligonucleotides indicated that UV-activation of a PMMA microchannel with an aspect ratio of ???3 was significantly less efficient toward the bottom of the channel compared to the upper sections. This effect was a consequence of the bulk polymer&apos;s damping of the modifying UV radiation due to absorption artifacts. In contrast, this effect was less pronounced for COC. Moreover, we observed that after thermal fusion bonding of the device&apos;s cover plate to the substrate, many of the generated functional groups buried into the bulk rendering them inaccessible. The propensity of this surface reorganization was found to be higher for PMMA compared to COC. As an example of the effects of material and microchannel aspect ratios on device functionality, thermoplastic devices for the selection of CTCs from whole blood were evaluated, which required the immobilization of monoclonal antibodies to channel walls. From our results, we concluded the CTC yield and purity of isolated CTCs were dependent on the substrate material with COC producing the highest clinical yields for CTCs as well as better purities compared to PMMA.close9

Central blockade of oxytocin receptors during mid-late gestation reduces amplitude of slow afterhyperpolarization in supraoptic oxytocin neurons

The neurohypophysial hormone oxytocin (OT), synthesized in magnocellular paraventricular (PVN) and supraoptic (SON) nuclei, is well known for its effects in lactation. Our previous studies showed that central OT receptor (OTR) binding is increased during gestation and that blockade of central OTRs, specifically during mid-late gestation, causes a delay in OT release during suckling and reduces weight gain in pups, suggesting decreased milk delivery. In the present study, we tested whether central OTR blockade during late gestation disrupts the gestation-related plasticity in intrinsic membrane properties. Whole cell current-clamp recordings were performed in OT neurons from pregnant rats (19-22 days in gestation) that were infused with an OTR antagonist (OTA) or artificial cerebrospinal fluid (aCSF) and from virgin rats infused with aCSF into the third ventricle via an osmotic minipump beginning on days 12-14 of gestation. The amplitudes of both Ca2+-dependent afterhyperpolarizations (AHPs), an apamin-sensitive medium AHP (mAHP) and an apamin-insensitive slow AHP (sAHP), were significantly increased during late gestation in control pregnant animals. However, the amplitude of the sAHP from pregnant rats treated with the OTA was significantly smaller than that of pregnant control rats and similar to that of virgins. These results indicate that the diminished efficiency in lactation due to OTR blockade may be partly a result of an altered sAHP that would shape OT bursting. These findings suggest that central actions of OT during late gestation are necessary for programming the plasticity of at least some of the intrinsic membrane properties in OT neurons during lactation. Copyright © 2008 the American Physiological Society