186 research outputs found

    Systemic markers of inflammation are independently associated with S100B concentration: results of an observational study in subjects with acute ischaemic stroke

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    <p>Abstract</p> <p>Background</p> <p>Vascular dysfunction and brain inflammation are thought to contribute to the pathophysiology of cerebral injury in acute stroke. However acute inflammation and vascular dysfunction may simply be markers of an acute phase response to cerebral injury, reflecting the size of the cerebral lesion. We aimed to determine if systemic markers of vascular dysfunction and inflammation are independently associated with concentrations of the astroglial protein S100B, a marker of brain injury, in participants with acute ischaemic stroke.</p> <p>Methods</p> <p>Fifty-seven men and women recruited within 96 hours of acute ischaemic stroke at two tertiary hospitals participated in this cross sectional observational study. Clinical, imaging (stroke lesions area measured with perfusion CT) and laboratory data were the independent variables and co-variates. The outcome variable was serum S100B concentration, analysed by multivariate regression.</p> <p>Results</p> <p>High sensitivity-CRP (<it>B </it>= 0.41) and lesion area (<it>B </it>= 0.69) were independently associated with S100B concentration (R<sup>2 </sup>= 0.75, p < 0.01). Other variables with significant univariate associations with S100B concentration were not independently associated with S100B concentration in the final multivariate model.</p> <p>Conclusion</p> <p>The degree of systemic inflammation is associated with S100B concentration in acute ischaemic stroke, independent of the size of the ischaemic lesion.</p

    The importance of left atrial volume assessment in identifying the cause of ischemic stroke

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    Separating cardioembolic from large artery stroke has important treatment implications. We investigated whether echocardiography could improve Cardioembolic Stroke (CES) prediction compared with traditional measures and cholesterol biomarkers. Data from 40 consecutive patients presenting with acute ischemic stroke which included brain and carotid imaging, ECG, echo, serum cholesterol and apolipoproteins were independently reviewed. Patients were classified into two groups: a) CES, defined by sustained or paroxysmal atrial fibrillation and \u3c50% stenosis of a perfusing cerebral artery; b) Large artery stroke (LAS) defined as \u3e 50% stenosis of an ipsilateral perfusing cerebral artery, with no evidence of AF on monitoring or evidence of small artery disease on neuroimaging and confirmed by an independent neurologist. Other than the CES group being older, the baseline characteristics of the two groups were similar. Left Atrial Volume (indexed for body surface area, LAVi) was significantly larger in CES (57.9 +/- 19.4 vs 31.1 +/- 8.3ml/m2, p\u3c0.01), with a simple equation that utilised age, LAVi and E wave accurately predicting 90% of CES. The difference in LAVi for CES was beyond that anticipated from the presence of AF alone. No differences in any of the lipid biomarkers were observed. These finding indicate that LAVi is the most important predictor of CES due to atrial fibrillation and is highly predictive of patients with CES due to atrial fibrillation. Cholesterol biomarkers offered no additional discriminatory value

    Systemic vascular function, measured with forearm flow mediated dilatation, in acute and stable cerebrovascular disease: a case-control study

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    BACKGROUND Acute ischaemic stroke is associated with alteration in systemic markers of vascular function. We measured forearm vascular function (using forearm flow mediated dilatation) to clarify whether recent acute ischaemic stroke/TIA is associated with impaired systemic vascular function. METHODS Prospective case control study enrolling 17 patients with recent acute ischaemic stroke/TIA and 17 sex matched controls with stroke more than two years previously. Forearm vascular function was measured using flow medicated dilatation (FMD). RESULTS Flow mediated dilatation was 6.0 ± 1.1% in acute stroke/TIA patients and 4.7 ± 1.0% among control subjects (p = 0.18). The mean paired difference in FMD between subjects with recent acute stroke and controls was 1.25% (95% CI -0.65, 3.14; p = 0.18). Endothelium independent dilatation was measured in six pairs of participants and was similar in acute stroke/TIA patients (22.6 ± 4.3%) and control subjects (19.1 ± 2.6%; p = 0.43). CONCLUSIONS Despite the small size of this study, these data indicate that recent acute stroke is not necessarily associated with a clinically important reduction in FMD.This study was funded by the Centre for Training in Clinical Cerebrovascular and Cardiovascular Research, a National Health and Medical Research Council funded Centre of Clinical Research Excellence

    FIGHT-PD: A feasibility study of periodized boxing training for Parkinson disease

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    Background: Boxing training has become a popular form of exercise for people with Parkinson disease (PD). There is a dearth of high-quality feasibility, safety, and efficacy data on boxing training for PD. Feasibility of Instituting Graduated High-intensity Training (FIGHT-PD) aimed to examine these features in a periodized boxing training program featuring high-intensity physical and cognitive demands. Objective: To conduct a feasibility study, aiming to address deficiencies in the current knowledge base and to provide data for future studies. Design: Single-arm, open-label feasibility. Setting: University department and medical research institute. Participants: Ten people with early stage PD without contraindications to intense exercise, identified from a database of participants interested in boxing training. Interventions: A 15-week exercise program with three 1-hour sessions per week, with each session including warmup and then rounds of noncontact boxing using a training device. Three distinct blocks of 5 weeks including active rest. Boxers Development: focus on training technique Boxers Cardio: increasing intensity, including high-intensity interval training Boxers Brain: focus on cognitively challenging dual task training. Main Outcome Measures: Process, resource, and management measures including recruitment and retention rates, timelines and costs, and compliance with prescribed exercise targets. Clinical outcomes were safety (adverse events), training intensity (using heart rate and perceived exertion monitoring), tolerability (pain, fatigue, and sleep scores), and pre- and postprogram Unified Parkinson Disease Rating Scale (UPDRS-III). Results: Among 10 participants from a pool of 82 (recruitment rate = 12%), there were no withdrawals; 348/360 workouts were completed (adherence = 97.7%); 4/348 (1.1%) workouts were missed due to minor injury. Nine of 10 participants showed improvement in UPDRS motor score. Conclusions: FIGHT-PD provides a depth of feasibility and safety data, methodological detail, and preliminary results that is not described elsewhere and could provide a useful basis for future studies of boxing training for PD

    New Zealand Blackcurrant Extract Improves Cycling Performance and Fat Oxidation in Cyclists

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    PURPOSE: Blackcurrant intake increases peripheral blood flow in humans, potentially by anthocyanin-induced vasodilation which may affect substrate delivery and exercise performance. We examined the effects of New Zealand blackcurrant (NZBC) extract on substrate oxidation, cycling time-trial performance and plasma lactate responses following the time-trial in trained cyclists. METHODS: Using a randomized, double-blind, crossover design, fourteen healthy men (age: 38 ± 13 years, height: 178 ± 4 cm, body mass: 77 ± 9 kg, V?O2max: 53 ± 6 ml·kg-1·min-1, mean ± SD) ingested NZBC extract (300 mg?day-1 CurraNZ™ containing 105 mg anthocyanin) or placebo (PL, 300 mg microcrystalline cellulose M102) for 7-days (washout 14-days). On day 7, participants performed 30 min of cycling (3x10 min at 45, 55 and 65% V?O2max), followed by a 16.1 km time-trial with lactate sampling during a 20-minute passive recovery. RESULTS: NZBC extract increased fat oxidation at 65% V?O2max by 27% (P < 0.05) and improved 16.1 km time-trial performance by 2.4% (NZBC: 1678 ± 108 s, PL: 1722 ± 131 s, P < 0.05). Plasma lactate was higher with NZBC extract immediately following the time-trial (NZBC: 7.06 ± 1.73 mmol?L-1, PL: 5.92 ± 1.58 mmol?L-1 P < 0.01). CONCLUSIONS: Seven days intake of New Zealand blackcurrant extract improves 16.1 km cycling time-trial performance and increases fat oxidation during moderate intensity cycling

    The impact of transcranial direct current stimulation on inhibitory control in young adults

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    In recent years, many important discoveries have been made to challenge current policy, guidelines, and practice regarding how best to prevent stroke associated with atherosclerotic stenosis of the origin of the internal carotid artery. TheUnited States Center forMedicare andMedicaid Services (CMS), for instance, is calling for expert advice as to whether its current policies should be modified. Using a thorough review of literature, 41 leading academic stroke-prevention clinicians from the United States and other countries, have united to advise CMS not to extend current reimbursement indications for carotid angioplasty/stenting (CAS) to patients with asymptomatic carotid stenosis or to patients with symptomatic carotid stenosis considered to be at low or standard risk from carotid endarterectomy (CEA). It was concluded that such expansion of reimbursement indications would have disastrous health and economic consequences for the United States and any other country that may follow such inappropriate action. This was an international effort because the experts to best advise CMS are relatively few and scattered around the world. In addition, US health policy, practice, and research have tended to have strong influences on other countries. © 2012 The Authors. Published by Wiley Periodicals, Inc

    Direct Measurements of Unimolecular and Bimolecular Reaction Kinetics of the Criegee Intermediate (CH 3 ) 2 COO

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    The Criegee intermediate acetone oxide, (CH3)2COO, is formed by laser photolysis of 2,2-diiodopropane in the presence of O2 and characterized by synchrotron photoionization mass spectrometry and by cavity ring-down ultraviolet absorption spectroscopy. The rate coefficient of the reaction of the Criegee intermediate with SO2 was measured using photoionization mass spectrometry and pseudo-first-order methods to be (7.3 ± 0.5) × 10–11 cm3 s–1 at 298 K and 4 Torr and (1.5 ± 0.5) × 10–10 cm3 s–1 at 298 K and 10 Torr (He buffer). These values are similar to directly measured rate coefficients of anti-CH3CHOO with SO2, and in good agreement with recent UV absorption measurements. The measurement of this reaction at 293 K and slightly higher pressures (between 10 and 100 Torr) in N2 from cavity ring-down decay of the ultraviolet absorption of (CH3)2COO yielded even larger rate coefficients, in the range (1.84 ± 0.12) × 10–10 to (2.29 ± 0.08) × 10–10 cm3 s–1. Photoionization mass spectrometry measurements with deuterated acetone oxide at 4 Torr show an inverse deuterium kinetic isotope effect, kH/kD = (0.53 ± 0.06), for reactions with SO2, which may be consistent with recent suggestions that the formation of an association complex affects the rate coefficient. The reaction of (CD3)2COO with NO2 has a rate coefficient at 298 K and 4 Torr of (2.1 ± 0.5) × 10–12 cm3 s–1 (measured with photoionization mass spectrometry), again similar to rate for the reaction of anti-CH3CHOO with NO2. Cavity ring-down measurements of the acetone oxide removal without added reagents display a combination of first- and second-order decay kinetics, which can be deconvolved to derive values for both the self-reaction of (CH3)2COO and its unimolecular thermal decay. The inferred unimolecular decay rate coefficient at 293 K, (305 ± 70) s–1, is similar to determinations from ozonolysis. The present measurements confirm the large rate coefficient for reaction of (CH3)2COO with SO2 and the small rate coefficient for its reaction with water. Product measurements of the reactions of (CH3)2COO with NO2 and with SO2 suggest that these reactions may facilitate isomerization to 2-hydroperoxypropene, possibly by subsequent reactions of association products

    Release of Spring 2013 Spanish-Language MCAS Test Items

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    Trace atmospheric concentrations of carboxylic acids have a potent effect upon the environment, where they modulate aqueous chemistry and perturb Earth’s radiative balance. Halogenated carboxylic acids are produced by the tropospheric oxidation of halocarbons and are considered persistent pollutants because of their weak tropospheric and aqueous sinks. However, recent studies reported rapid reactions between selected carboxylic acids and Criegee intermediates, which may provide an efficient gas-phase removal process. Accordingly, absolute rate coefficients of two Criegee intermediates, CH<sub>2</sub>OO and (CH<sub>3</sub>)<sub>2</sub>COO, with a suite of carboxylic acids (HCOOH, CH<sub>3</sub>COOH, CClF<sub>2</sub>COOH, CF<sub>3</sub>CF<sub>2</sub>COOH, and pyruvic acid) were measured with a view to develop a structure–activity relationship (SAR). This SAR is based upon the dipole-capture model and predicts the reactivity of many further combinations of Criegee intermediates and carboxylic acids. Complementary synchrotron-based photoionization mass spectrometry measurements demonstrate that these reactions produce stable ester adducts, with a reaction coordinate involving transfer of the acidic hydrogen from the carboxylic acid to the terminal oxygen of the Criegee intermediate. The adduct products are predicted to have low vapor pressures, and coupling of this chemistry with a global atmospheric chemistry and transport model shows significant production of secondary organic aerosol at locations rich in biogenic alkene emissions
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