The validity of capillary blood sampling in the determination of human growth hormone concentration during exercise in men

This is an open access article - Copyright © 2004 BMJ Publishing Group LtdBACKGROUND: Studies measuring human growth hormone (hGH) in blood during exercise have mainly used venous sampling. The invasive nature of this procedure makes evaluation of hGH impossible in various exercise environments. OBJECTIVE: To determine whether capillary sampling could offer an alternative sampling method. METHODS: Capillary and venous blood samples were collected for determination of hGH at the end of each exercise stage during an incremental exercise test in 16 male club level competitive cyclists (mean (SD) age 30.8 (8.0) years, body mass 72.2 (7.1) kg, body fat 12.9 (3.5)%, peak oxygen consumption 4.18 (0.46) l⋅min−1). Linear regression, from a plot of venous v capillary blood hGH concentration, showed a correlation coefficient of r = 0.986 (p<0.001). When geometric means and log transformations were used, a coefficient of variation of 14.2% was demonstrated between venous and capillary flow for hGH concentration. The mean ratio limits of agreement were 0.62 (1.72)—that is, 95% of the ratios were contained between 0.36 and 1.07, with a mean of 0.62. CONCLUSIONS: Capillary blood sampling is an acceptable alternative to venous sampling for determining hGH concentration during rest and exercise. Sample sites should not be used interchangeably: one site should be chosen and its use standardised

The complete sequence of the Acacia ligulata chloroplast genome reveals a highly divergent clpP1 gene

Legumes are a highly diverse angiosperm family that include many agriculturally important species. To date, 21 complete chloroplast genomes have been sequenced from legume crops confined to the Papilionoideae subfamily. Here we report the first chloroplast genome from the Mimosoideae, Acacia ligulata, and compare it to the previously sequenced legume genomes. The A. ligulata chloroplast genome is 158,724 bp in size, comprising inverted repeats of 25,925 bp and single-copy regions of 88,576 bp and 18,298 bp. Acacia ligulata lacks the inversion present in many of the Papilionoideae, but is not otherwise significantly different in terms of gene and repeat content. The key feature is its highly divergent clpP1 gene, normally considered essential in chloroplast genomes. In A. ligulata, although transcribed and spliced, it probably encodes a catalytically inactive protein. This study provides a significant resource for further genetic research into Acacia and the Mimosoideae. The divergent clpP1 gene suggests that Acacia will provide an interesting source of information on the evolution and functional diversity of the chloroplast Clp protease comple

Association between preoperative haemoglobin concentration and cardiopulmonary exercise variables: a multicentre study

Background: Preoperative anaemia and low exertional oxygen uptake are both associated with greater postoperative morbidity and mortality. This study reports the association among haemoglobin concentration ([Hb]), peak oxygen uptake (V_O2 peak) and anaerobic threshold (AT) in elective surgical patients. Methods: Between 1999 and 2011, preoperative [Hb] and cardiopulmonary exercise tests were recorded in 1,777 preoperative patients in four hospitals. The associations between [Hb], V_O2 peak and AT were analysed by linear regression and covariance. Results: In 436 (24.5%) patients, [Hb] was <12 g dl-1 and, in 83 of these, <10 g dl-1. Both AT and V_O2 peak rose modestly with increasing [Hb] (r2 = 0.24, P <0.0001 and r2 = 0.30, P <0.0001, respectively). After covariate adjustment, an increase in [Hb] of one standard deviation was associated with a 6.7 to 9.7% increase in V_O2 peak, and a rise of 4.4 to 6.0% in AT. Haemoglobin concentration accounted for 9% and 6% of the variation in V_O2 peak and AT respectively. Conclusions: To a modest extent, lower haemoglobin concentrations are independently associated with lower oxygen uptake during preoperative cardiopulmonary exercise testing. It is unknown whether this association is causative

Scaling physiological measurements for individuals of different body size.

This paper examines how selected physiological performance variables, such as maximal oxygen uptake, strength and power, might best be scaled for subject differences in body size. The apparent dilemma between using either ratio standards or a linear adjustment method to scale was investigated by considering how maximal oxygen uptake (l.min-1), peak and mean power output (W) might best be adjusted for differences in body mass (kg). A curvilinear power function model was shown to be theoretically, physiologically and empirically superior to the linear models. Based on the fitted power functions, the best method of scaling maximum oxygen uptake, peak and mean power output, required these variables to be divided by body mass, recorded in the units kg 2/3. Hence, the power function ratio standards (ml.kg-2/3.min-1) and (W.kg-2/3) were best able to describe a wide range of subjects in terms of their physiological capacity, i.e. their ability to utilise oxygen or record power maximally, independent of body size. The simple ratio standards (ml.kg-1.min-1) and (W.kg-1) were found to best describe the same subjects according to their performance capacities or ability to run which are highly dependent on body size. The appropriate model to explain the experimental design effects on such ratio standards was shown to be log-normal rather than normal. Simply by taking logarithms of the power function ratio standard, identical solutions for the design effects are obtained using either ANOVA or, by taking the unscaled physiological variable as the dependent variable and the body size variable as the covariate, ANCOVA methods

Isolation and characterization of microsatellite markers for the banded ironstone endemic acacia karina (Leguminosae: Mimosaceae) and cross-species amplification with A. stanleyi and A. jibberdingensis

Microsatellite markers were developed for the banded ironstone endemic shrub Acacia karina to examine genetic diversity, range-wide differentiation and mating system parameters. Nine loci were developed and in a sample of 20 individuals from one population the number of alleles ranged from 4 to 12 per locus and observed heterozygosities from 0.556 to 0.824. All loci were tested for cross-species amplification in two other south-west Australian Acacia species thought to be closely related to A. karina. Of these nine loci, eight were polymorphic in A. jibberdingensis and three in A. stanleyi. © Springer Science+Business Media B.V. 2010

Allometric scaling of strength measurements to body size

For comparative purposes, normalisation of strength measures to body size using allometric scaling is recommended. A wide range of scaling exponents have been suggested, typically utilising body mass, although a comprehensive evaluation of different body size variables has not been documented. Differences between force (F) and torque (T) measurements of strength, and the velocity of measurement might also explain some of the variability in the scaling exponents proposed. Knee extensor strength of 86 young men was assessed with measurement of torque at four velocities (0-4.19 rad s(-1)) and force measured isometrically. Body size variables included body mass, height and fat-free mass. Scaling exponents for torque were consistently higher than for force, but the velocity of torque measurement had no influence. As the confounding effects of fat mass were restricted, scaling exponents and the strength of the power-function relationships progressively increased. Fat-free mass determined a surprisingly high proportion of the variance in measured strength (F, 31%; T, 52-58%). Absolute force and torque measurements, and even torque normalised for body mass, were significantly influenced by height, although strength measures normalised to fat-free mass were not. To normalise strength measurements to body mass, for relatively homogenous lean populations (body fat 20%) lower body mass exponents appear more suitable (F, 0.45; T, 0.68). Nevertheless, fat-free mass is the recommended index for scaling strength to body size, and higher exponents (F, 0.76; T, 1.12) are advocated in this case