437 research outputs found
The physiological, perceptual and neuromuscular responses of team sport athletes to a running and cycling high intensity interval training session
Purpose: The acute physiological, perceptual and neuromuscular responses to volume-matched running and cycling high intensity interval training (HIIT) were studied in team sport athletes.
Methods: In a randomized cross-over design, 11 male team sport players completed 3 × 6 min (with 5 min between sets) repeated efforts of 15 s exercising at 120% speed (sV ˙ O2max) or power (pV ˙ O2max) at V ˙ O2max followed by 15 s passive recovery on a treadmill or cycle ergometer, respectively.
Results: Absolute mean V ˙ O2 (ES [95% CI] = 1.46 [0.47–2.34], p 90% V ˙ O2max during the HIIT was higher for running compared to cycling (ES [95% CI] = 1.21 [0.26–2.07], p = 0.015). Overall differential RPE (dRPE) (ES [95% CI] = 0.55 [− 0.32–1.38], p = 0.094) and legs dRPE (ES [95% CI] = − 0.65 [− 1.48–0.23], p = 0.111) were similar, whereas breathing dRPE (ES [95% CI] = 1.01 [0.08–1.85], p = 0.012) was higher for running. Maximal isometric knee extension force was unchanged after running (ES [95% CI] = − 0.04 [− 0.80–0.8], p = 0.726) compared to a moderate reduction after cycling (ES [95% CI] = − 1.17 [− 2.02–0.22], p = 0.001).
Conclusion: Cycling HIIT in team sport athletes is unlikely to meet the requirements for improving run-specific metabolic adaptation but might offer a greater lower limb neuromuscular load
The effects of an acute dose of New Zealand blackcurrant extract on 5 km running performance
This study investigated the effects of an acute dose (900 mg) of New Zealand Blackcurrant (NZBC) extract on 5-km running performance, alongside associated physiological and metabolic responses. Sixteen trained male runners (age 26 ± 5 years, stature 173.4 ± 7.3 cm, body mass 73.7 ± 6.9 kg, maximal oxygen consumption [ ˙VO2max ] 55.4 ± 6.1 ml·kg−1·min−1) ingested either capsules containing NZBC extract (3 × 300 mg CurraNZ, 315 mg anthocyanins) or a matched placebo (3 × 300 mg gluten-free flour) 2 hr before exercise in a double-blind, randomized, crossover design. Performance time, physiological, and metabolic responses were assessed in a 5-km time trial, preceded by 10-min exercise at the lactate threshold on a treadmill. NZBC extract did not alter the physiological or metabolic responses to exercise at the lactate threshold (oxygen uptake, respiratory exchange ratio, minute ventilation, carbohydrate oxidation, fat oxidation, heart rate, blood lactate, or rating of perceived exertion, p > .05). The 5-km time trial was completed in a faster time in the NZBC extract condition compared with placebo (NZBC: 1,308.96 ± 122.36 s, placebo: 1,346.33 ± 124.44, p = .001, d = −0.23, confidence interval range = [−0.46, 0.00 s]). No differences in physiological or metabolic responses were apparent between conditions for the 5-km time trial (p > .05). Ingesting 900 mg of NZBC extract as an acute dose improves performance in trained male runners without altering physiological or metabolic responses to exercise. Further research is needed to assess a wider range of possible mechanisms (e.g., cardiovascular function, metabolite profiles) to advance insight into improved performance following supplementation
The PTPN22 Locus and Rheumatoid Arthritis: No Evidence for an Effect on Risk Independent of Arg620Trp
The Trp(620) allotype of PTPN22 confers susceptibility to rheumatoid arthritis (RA) and certain other classical autoimmune diseases. There has been a report of other variants within the PTPN22 locus that alter risk of RA; protective haplotype '5', haplotype group '6-10' and susceptibility haplotype '4', suggesting the possibility of other PTPN22 variants involved in the pathogenesis of RA independent of R620W (rs2476601). Our aim was to further investigate this possibility.A total of 4,460 RA cases and 4,481 controls, all European, were analysed. Single nucleotide polymorphisms rs3789607, rs12144309, rs3811021 and rs12566340 were genotyped over New Zealand (NZ) and UK samples. Publically-available Wellcome Trust Case Control Consortium (WTCCC) genotype data were used.The protective effect of haplotype 5 was confirmed (rs3789607; (OR = 0.91, P = 0.016), and a second protective effect (possibly of haplotype 6) was observed (rs12144309; OR = 0.90, P = 0.021). The previously reported susceptibility effect of haplotype 4 was not replicated; instead a protective effect was observed (rs3811021; OR = 0.85, P = 1.4×10(-5)). Haplotypes defined by rs3789607, rs12144309 and rs3811021 coalesced with the major allele of rs12566340 within the adjacent BFK (B-cell lymphoma 2 (BCL2) family kin) gene. We, therefore, tested rs12566340 for association with RA conditional on rs2476601; there was no evidence for an independent effect at rs12566340 (P = 0.76). Similarly, there was no evidence for an independent effect at rs12566340 in type 1 diabetes (P = 0.85).We have no evidence for a common variant additional to rs2476601 within the PTPN22 locus that influences the risk of RA. Arg620Trp is almost certainly the single common causal variant
Hyperoxia results in increased aerobic metabolism following acute brain injury
Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO2 cytochrome c oxidase, the terminal electron acceptor in the mitochondrial respiratory chain, fails to sustain oxidative phosphorylation. After acute brain injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated the oxygen dependency of aerobic metabolism in 16 acutely brain-injured patients using a 120-min normobaric hyperoxia challenge in the acute phase (24–72 h) post-injury and multimodal neuromonitoring, including transcranial Doppler ultrasound-measured cerebral blood flow velocity, cerebral microdialysis-derived lactate-pyruvate ratio (LPR), brain tissue pO2 (pbrO2), and tissue oxygenation index and cytochrome c oxidase oxidation state (oxCCO) measured using broadband spectroscopy. Increased inspired oxygen resulted in increased pbrO2 [ΔpbrO2 30.9 mmHg p < 0.001], reduced LPR [ΔLPR −3.07 p = 0.015], and increased cytochrome c oxidase (CCO) oxidation (Δ[oxCCO] + 0.32 µM p < 0.001) which persisted on return-to-baseline (Δ[oxCCO] + 0.22 µM, p < 0.01), accompanied by a 7.5% increase in estimated cerebral metabolic rate for oxygen (p = 0.038). Our results are consistent with an improvement in cellular redox state, suggesting oxygen-limited metabolism above recognised ischaemic pbrO2 thresholds. Diffusion limitation or mitochondrial inhibition might explain these findings. Further investigation is warranted to establish optimal oxygenation to sustain aerobic metabolism after acute brain injury
Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species
<p>Abstract</p> <p>Background</p> <p>In the mid 20<sup>th </sup>century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found.</p> <p>Results</p> <p>Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes). Predicted barriers separate into two distinct categories: (i) single cohesive barriers (< 50,000 km<sup>2</sup>), associated with taxa that differentiate at smaller spatial scales (salamander: <it>Ensatina eschscholtzii</it>; tree: <it>Acacia karroo</it>); and (ii) composite barriers - formed by groups of barriers (each 184,000 to 1.7 million km<sup>2</sup>) in close geographic proximity (totaling 1.9 to 2.3 million km<sup>2</sup>) - associated with taxa that differentiate at larger spatial scales (birds: <it>Phylloscopus trochiloide</it>s and <it>Larus </it>(sp. <it>argentatus </it>and <it>fuscus</it>)). When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal.</p> <p>Conclusions</p> <p>While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i) requires no <it>a priori </it>information on the relative importance of features that define barriers, (ii) can be replicated using any kind of continuously distributed environmental variable, and (iii) generates spatially explicit hypotheses of geographic species formation. The methods developed here - combined with study of the geographical ecology and genetics of taxa in their environments - should enable recognition of ring species phenomena throughout the world.</p
The ITGAV rs3738919 variant and susceptibility to rheumatoid arthritis in four Caucasian sample sets
INTRODUCTION: Angiogenesis is an important process in the development of destructive synovial pannus in rheumatoid arthritis (RA). The ITGAV +gene encodes a cell cycle-associated antigen, integrin alphanubeta 3, which plays a role in RA angiogenesis. Previously, two independent studies identified an association between the major allele of the ITGAV single-nucleotide polymorphism (SNP) rs3738919 and RA. We therefore tested this association in an independent study using New Zealand (NZ) and Oxford (UK) RA case control samples. METHODS: We compared genotype frequencies in 740 NZ Caucasian RA patients and 553 controls genotyped for rs3738919, using a polymerase chain reaction-restriction fragment length polymorphism assay. A TaqMan genotyping SNP assay was used to type 713 Caucasian RA patients and 515 control samples from Oxford for the rs3738919 variant. Association of rs3738919 with RA was tested in these two sample sets using the chi-square goodness-of-fit test. The Mantel-Haenszel test was used to perform a meta-analysis, combining the genetic results from four independent Caucasian case control cohorts, consisting of 3,527 cases and 4,126 controls. Haplotype analysis was also performed using SNPs rs3911238, rs10174098 and rs3738919 in the Wellcome Trust Case Control Consortium, NZ and Oxford case control samples. RESULTS: We found no evidence for association between ITGAV and RA in either the NZ or Oxford sample set (odds ratio [OR] = 0.88, P(allelic) = 0.11 and OR = 1.18, P(allelic) = 0.07, respectively). Inclusion of these data in a meta-analysis (random effects) of four independent cohorts (3,527 cases and 4,126 controls) weakens support for the hypothesis that rs3738919 plays a role in the development of RA (OR(combined) = 0.92, 95% confidence interval 0.80 to 1.07; P = 0.29). No consistent haplotype associations were evident. CONCLUSIONS: Association of ITGAV SNP rs7378919 with RA was not replicated in NZ or Oxford case control sample sets. Meta-analysis of these and previously published data lends limited support for a role for the ITGAV in RA in Caucasians of European ancestry
Only one independent genetic association with rheumatoid arthritis within the KIAA1109-TENR-IL2-IL21 locus in Caucasian sample sets: confirmation of association of rs6822844 with rheumatoid arthritis at a genome-wide level of significance
INTRODUCTION: The single nucleotide polymorphism (SNP) rs6822844 within the KIAA1109-TENR-IL2-IL21 gene cluster has been associated with rheumatoid arthritis (RA). Other variants within this cluster, including rs17388568 that is not in linkage disequilibrium (LD) with rs6822844, and rs907715 that is in moderate LD with rs6822844 and rs17388568, have been associated with a number of autoimmune phenotypes, including type 1 diabetes (T1D). Here we aimed to: one, confirm at a genome-wide level of significance association of rs6822844 with RA and, two, evaluate whether or not there were effects independent of rs6822844 on RA at the KIAA1109-TENR-IL2-IL21 locus. METHODS: A total of 842 Australasian RA patients and 1,115 controls of European Caucasian ancestry were genotyped for rs6822844, rs17388568 and rs907715. Meta-analysis of these data with published and publicly-available data was conducted using STATA. RESULTS: No statistically significant evidence for association was observed in the Australasian sample set for rs6822844 (odds ratio (OR)=0.95 (0.80 to 1.12), P=0.54), or rs17388568 (OR=1.03 (0.90 to 1.19), P=0.65) or rs907715 (OR=0.98 (0.86 to 1.12), P=0.69). When combined in a meta-analysis using data from a total of 9,772 cases and 10,909 controls there was a genome-wide level of significance supporting association of rs6822844 with RA (OR=0.86 (0.82 to 0.91), P=8.8x10(-8), P=2.1x10(-8) including North American Rheumatoid Arthritis Consortium data). Meta-analysis of rs17388568, using a total of 6,585 cases and 7,528 controls, revealed no significant association with RA (OR=1.03, (0.98 to 1.09); P=0.22) and meta-analysis of rs907715 using a total of 2,689 cases and 4,045 controls revealed a trend towards association (OR=0.93 (0.87 to 1.00), P=0.07). However, this trend was not independent of the association at rs6822844. CONCLUSIONS: The KIAA1109-TENR-IL2-IL21 gene cluster, that encodes an interleukin (IL-21) that plays an important role in Th17 cell biology, is the 20th locus for which there is a genome-wide (P ≤ 5x10(-8)) level of support for association with RA. As for most other autoimmune diseases, with the notable exception of T1D, rs6822844 is the dominant association in the locus. The KIAA1109-TENR-IL2-IL21 locus also confers susceptibility to other autoimmune phenotypes with a heterogeneous pattern of association
Protocol for direct reporting of awareness in maternity patients (DREAMY): a prospective, multicentre cohort study of accidental awareness during general anaesthesia
12 months embargo applie
Delivering strong 1H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange
Hyperpolarization turns typically weak NMR and MRI responses into strong signals so that ordinarily impractical measurements become possible. The potential to revolutionize analytical NMR and clinical diagnosis through this approach reflect this area's most compelling outcomes. Methods to optimize the low cost parahydrogen based approach signal amplification by reversible exchange (SABRE) with studies on a series of biologically relevant nicotinamides and methyl nicotinates are detailed. These procedures involve specific 2H-labelling in both the agent and catalyst and achieve polarization lifetimes of ca. 2 minutes with 50% polarization in the case of 4,6-d2-methylnicotinate. As a 1.5 T hospital scanner has an effective 1H polarization level of just 0.0005% this strategy should result in compressed detection times for chemically discerning measurements that probe disease. To demonstrate this techniques generality, we exemplify further studies on a range of pyridazine, pyrimidine, pyrazine and isonicotinamide analogues that feature as building blocks in biochemistry and many disease treating drugs
Does Forced Voting Result in Political Polarization?
This paper estimates the effects of the compulsory voting laws on individuals´ political orientations though a regression discontinuity framework. The identification comes from Brazil´s dual voting system – voluntary and compulsory – whose exposure is determined based on citizens’ dates of birth. Using self-collected data, we find that compulsory voting has sizable effects on individuals´ political preferences, making them more likely to identify with a political party and to become oriented towards ideological extremes
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