834 research outputs found

    Cardiorespiratory Fitness Modulates The Acute Flow-Mediated Dilation Response Following High-Intensity But Not Moderate-Intensity Exercise In Elderly Men.

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    Impaired endothelial function is observed with ageing and with low cardiorespiratory fitness (VO2peak) whilst improvements in both are suggested to be reliant on higher-intensity exercise in the elderly. This may be due to the flow-mediated dilation (FMD) response to acute exercise of varying intensity. We examined the hypothesis that exercise-intensity alters the FMD response in healthy elderly adults, and would be modulated by VO2peak Forty-seven elderly men were stratified into lower- (VO2peak = 24.3±2.9 ml.kg(-1)min(-1), n=27) and higher-fit groups (VO2peak = 35.4±5.5 ml.kg(-1)min(-1), n=20) after a test of cycling peak power output (PPO). In randomised order, participants undertook 27 min moderate-intensity continuous (MICE; 40% PPO) or high-intensity interval cycling exercise (HIIE; 70% PPO), or no-exercise control. Brachial FMD was assessed at rest, 10 and 60 min after exercise. In control, FMD reduced in both groups (P=0.05). FMD increased after MICE in both groups [increase of 0.86 % (95% CI, 0.17 to 1.56), P=0.01], and normalised after 60 min. In the lower-fit, FMD reduced after HIIE [reduction of 0.85 % (95% CI, 0.12 to 1.58), P=0.02), and remained decreased at 60 min (P=0.05). In the higher-fit FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52 % (95% CI, 0.41 to 2.62), P<0.01], which was correlated with VO2peak (r =0.41; P<0.01). Exercise-intensity alters the FMD response in elderly adults, and VO2peak modulates the FMD response following HIIE, but not MICE. The sustained decrease in FMD in the lower-fit may represent a signal for vascular adaptation or endothelial fatigue

    Acute Dietary Nitrate Supplementation Improves Flow Mediated Dilatation of the Superficial Femoral Artery in Healthy Older Males

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    Aging is often associated with reduced leg blood flow, increased arterial stiffness, and endothelial dysfunction, all of which are related to declining nitric oxide (NO) bioavailability. Flow mediated dilatation (FMD) and passive leg movement (PLM) hyperaemia are two techniques used to measure NO-dependent vascular function. We hypothesised that acute dietary nitrate (NO3−) supplementation would improve NO bioavailability, leg FMD, and PLM hyperaemia. Fifteen healthy older men (69 ± 4 years) attended two experiment sessions and consumed either 140 mL of concentrated beetroot juice (800 mg NO3−) or placebo (NO3−-depleted beetroot juice) in a randomised, double blind, cross-over design study. Plasma nitrite (NO2−) and NO3−, blood pressure (BP), augmentation index (AIx75), pulse wave velocity (PWV), FMD of the superficial femoral artery, and PLM hyperaemia were measured immediately before and 2.5 h after consuming NO3− and placebo. Placebo had no effect but NO3− led to an 8.6-fold increase in plasma NO2−, which was accompanied by an increase in FMD (NO3−: +1.18 ± 0.94% vs. placebo: 0.23 ± 1.13%, p = 0.002), and a reduction in AIx75 (NO3−: −8.7 ± 11.6% vs. placebo: −4.6 ± 5.5%, p = 0.027). PLM hyperaemia, BP, and PWV were unchanged during both trials. This study showed that a dose of dietary NO3− improved NO bioavailability and enhanced endothelial function as measured by femoral artery FMD. These findings provide insight into the specific central and peripheral vascular responses to dietary NO3− supplementation in older adult

    Reference Intervals for Brachial Artery Flow-Mediated Dilation and the Relation With Cardiovascular Risk Factors.

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    Endothelial function, assessed using brachial artery flow-mediated dilation (FMD), predicts future cardiovascular disease (CVD) risk. This study established age- and sex-specific reference intervals for brachial artery FMD in healthy individuals and examined the relation with CVD risk factors. In a retrospective study design, we pooled brachial artery FMD (acquired according to expert-consensus guidelines for FMD protocol and analysis) and participant characteristics/medical history from 5362 individuals (4-84 years; 2076 females). Healthy individuals (n=1403 [582 females]) were used to generate age-/sex-specific percentile curves. Subsequently, we included individuals with CVD risk factors, without overt disease (unmedicated n=3167 [1247 females] and medicated n=792 [247 females]). Multiple linear regression tested the relation of CVD risk factors (body mass index, blood pressure, cholesterol, diabetes, dyslipidemia, and smoking) with FMD. Healthy males showed a negative, curvilinear relation between FMD and age, while females revealed a negative linear relation that started higher but declined at a faster rate than males. Age- and sex-specific differences in FMD relate, at least partly, to baseline artery diameter. FMD was related to CVD risk factors in unmedicated (eg, systolic/diastolic blood pressure) and medicated individuals (eg, diabetes/dyslipidemia). Sex mediated some of these effects (P<0.05), with normalization of FMD in medicated men, but not women with dyslipidemia. In conclusion, sex alters the age-related decline in FMD, which may partly be explained through differences in baseline diameter. Sex also alters the influence of some CVD risk factors and medication on FMD. This work improves interpretation and future use of the FMD technique

    Measurement of the Forward-Backward Asymmetry in the B -> K(*) mu+ mu- Decay and First Observation of the Bs -> phi mu+ mu- Decay

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    We reconstruct the rare decays B+→K+ÎŒ+Ό−B^+ \to K^+\mu^+\mu^-, B0→K∗(892)0ÎŒ+Ό−B^0 \to K^{*}(892)^0\mu^+\mu^-, and Bs0→ϕ(1020)ÎŒ+Ό−B^0_s \to \phi(1020)\mu^+\mu^- in a data sample corresponding to 4.4fb−14.4 {\rm fb^{-1}} collected in ppˉp\bar{p} collisions at s=1.96TeV\sqrt{s}=1.96 {\rm TeV} by the CDF II detector at the Fermilab Tevatron Collider. Using 121±16121 \pm 16 B+→K+ÎŒ+Ό−B^+ \to K^+\mu^+\mu^- and 101±12101 \pm 12 B0→K∗0ÎŒ+Ό−B^0 \to K^{*0}\mu^+\mu^- decays we report the branching ratios. In addition, we report the measurement of the differential branching ratio and the muon forward-backward asymmetry in the B+B^+ and B0B^0 decay modes, and the K∗0K^{*0} longitudinal polarization in the B0B^0 decay mode with respect to the squared dimuon mass. These are consistent with the theoretical prediction from the standard model, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the Bs0→ϕΌ+Ό−decayandmeasureitsbranchingratioB^0_s \to \phi\mu^+\mu^- decay and measure its branching ratio {\mathcal{B}}(B^0_s \to \phi\mu^+\mu^-) = [1.44 \pm 0.33 \pm 0.46] \times 10^{-6}using using 27 \pm 6signalevents.Thisiscurrentlythemostrare signal events. This is currently the most rare B^0_s$ decay observed.Comment: 7 pages, 2 figures, 3 tables. Submitted to Phys. Rev. Let

    Non-steroidal anti-inflammatory drug-induced apoptosis in gastric cancer cells is blocked by protein kinase C activation through inhibition of c-myc

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    Apoptosis plays a major role in gastrointestinal epithelial cell turnover, ulcerogenesis and tumorigenesis. We have examined apoptosis induction by non-steroidal anti-inflammatory drugs (NSAIDs) in human gastric (AGS) cancer cells and the role of protein kinase C (PKC) and apoptosis-related oncogenes. After treatment with aspirin or indomethacin, cell growth was quantified by MTT assay, and apoptosis was determined by acridine orange staining, DNA fragmentation and flow cytometry. The mRNA and protein of p53, p21waf1/cip1 and c-myc was detected by Northern and Western blotting respectively. The influence of PKC on indomethacin-induced apoptosis was determined by co-incubation of 12-O-tetradecanoylphorbol 13-acetate (TPA). The role of c-myc was determined using its antisense oligonucleotides. The results showed that both aspirin and indomethacin inhibited cell growth and induced apoptosis of AGS cells in a dose- and time-dependent manner, without altering the cell cycle. Indomethacin increased c-myc mRNA and protein, whereas p53 and p21waf1/cip1 were unchanged. Down-regulation of c-myc by its antisense oligonucleotides reduced apoptosis induction by indomethacin. TPA could inhibit indomethacin-induced apoptosis and accumulate cells in G2/M. Overexpression of c-myc was inhibited by TPA and p21waf1/cip1 mRNA increased. In conclusion, NSAIDs induce apoptosis in gastric cancer cells which may be mediated by up-regulation of c-myc proto-oncogene. PKC activation can abrogate the effects of NSAIDs by decreasing c-myc expression. © 1999 Cancer Research Campaig

    Coevolution of dispersal in a parasitoid-host system

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    Interspecific interactions and the evolution of dispersal are both of interest when considering the potential impact of habitat fragmentation on community ecology, but the interaction between these processes is not well studied. We address this by considering the coevolution of dispersal strategies in a host-parasitoid system. An individual-based host-parasitoid metapopulation model was constructed for a patchy environment, allowing for evolution in dispersal rates of both species. Highly rarefied environments with few suitable patches selected against dispersal in both species, as did relatively static environments. Provided that parasitoids persist, all parameter values studied led to stable equilibria in dispersal rates for both species. There was a tendency towards higher dispersal rates in parasitoids due to the asymmetric relationships of the two species to the patches: vacant patches are most valuable for hosts, but unsuitable for parasitoids, which require an established host population to reproduce. High host dispersal rate was favoured by high host population growth rate, and in the parasitoid by high growth rates in both species

    Measurements of the properties of Lambda_c(2595), Lambda_c(2625), Sigma_c(2455), and Sigma_c(2520) baryons

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    We report measurements of the resonance properties of Lambda_c(2595)+ and Lambda_c(2625)+ baryons in their decays to Lambda_c+ pi+ pi- as well as Sigma_c(2455)++,0 and Sigma_c(2520)++,0 baryons in their decays to Lambda_c+ pi+/- final states. These measurements are performed using data corresponding to 5.2/fb of integrated luminosity from ppbar collisions at sqrt(s) = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. Exploiting the largest available charmed baryon sample, we measure masses and decay widths with uncertainties comparable to the world averages for Sigma_c states, and significantly smaller uncertainties than the world averages for excited Lambda_c+ states.Comment: added one reference and one table, changed order of figures, 17 pages, 15 figure

    Search for a New Heavy Gauge Boson Wprime with Electron + missing ET Event Signature in ppbar collisions at sqrt(s)=1.96 TeV

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    We present a search for a new heavy charged vector boson Wâ€ČW^\prime decaying to an electron-neutrino pair in ppˉp\bar{p} collisions at a center-of-mass energy of 1.96\unit{TeV}. The data were collected with the CDF II detector and correspond to an integrated luminosity of 5.3\unit{fb}^{-1}. No significant excess above the standard model expectation is observed and we set upper limits on σ⋅B(Wâ€Č→eÎœ)\sigma\cdot{\cal B}(W^\prime\to e\nu). Assuming standard model couplings to fermions and the neutrino from the Wâ€ČW^\prime boson decay to be light, we exclude a Wâ€ČW^\prime boson with mass less than 1.12\unit{TeV/}c^2 at the 95\unit{%} confidence level.Comment: 7 pages, 2 figures Submitted to PR
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