190 research outputs found

    Thrombolysis in Patients Aged over 80 Years Is Equally Effective and Safe

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    BACKGROUND: Despite stroke's high prevalence in the elderly, intravenous thrombolysis is licensed in Europe only for patients younger than 80 years old. We aimed to compare the functional outcomes and complication rates in patients older versus younger than 80 years old treated with intravenous thrombolysis. METHODS: A retrospective observational study of patients who received intravenous thrombolysis in a stroke unit between January 1, 2009, and June 30, 2012, was conducted. Variables were compared between 2 subgroups (≤80 and >80 years). RESULTS: Overall, 512 patients underwent intravenous thrombolysis, of which 13.1% were over 80 years. The mean age was 65.4 years in the younger subgroup and 82.9 years in the older subgroup. Prior independence rates did not differ between the subgroups. Prevalence of atrial fibrillation and cardioembolic stroke was higher in the older subgroup (P = .004 and .026). Only 3% of the elderly with atrial fibrillation were taking oral anticoagulants. Symptoms-to-needle time was lower in the older subgroup (P = .048). Stroke severity was higher in patients over 80 years (P = .026). There was significant improvement in the National Institutes of Health Stroke Scale score 7 days after intravenous thrombolysis (P < .001) in both subgroups. The proportion of patients with 3 months' favorable outcome and independence, hemorrhagic transformation, and mortality rates were similar in both subgroups. CONCLUSIONS: Elderly patients' benefits and outcomes from intravenous thrombolysis treatment were identical to the younger subgroup without excess hemorrhagic transformation or mortality. These results favor the use of intravenous thrombolysis in patients over 80 years.info:eu-repo/semantics/publishedVersio

    Nonlinear saturation of electrostatic waves: mobile ions modify trapping scaling

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    The amplitude equation for an unstable electrostatic wave in a multi-species Vlasov plasma has been derived. The dynamics of the mode amplitude ρ(t)\rho(t) is studied using an expansion in ρ\rho; in particular, in the limit γ0+\gamma\rightarrow0^+, the singularities in the expansion coefficients are analyzed to predict the asymptotic dependence of the electric field on the linear growth rate γ\gamma. Generically Ekγ5/2|E_k|\sim \gamma^{5/2}, as γ0+\gamma\rightarrow0^+, but in the limit of infinite ion mass or for instabilities in reflection-symmetric systems due to real eigenvalues the more familiar trapping scaling Ekγ2|E_k|\sim \gamma^{2} is predicted.Comment: 13 pages (Latex/RevTex), 4 postscript encapsulated figures which are included using the utility "uufiles". They should be automatically included with the text when it is downloaded. Figures also available in hard copy from the authors ([email protected]

    Coercivity and stability results for an extended Navier-Stokes system

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    In this article we study a system of equations that is known to {\em extend} Navier-Stokes dynamics in a well-posed manner to velocity fields that are not necessarily divergence-free. Our aim is to contribute to an understanding of the role of divergence and pressure in developing energy estimates capable of controlling the nonlinear terms. We address questions of global existence and stability in bounded domains with no-slip boundary conditions. Even in two space dimensions, global existence is open in general, and remains so, primarily due to the lack of a self-contained L2L^2 energy estimate. However, through use of new H1H^1 coercivity estimates for the linear equations, we establish a number of global existence and stability results, including results for small divergence and a time-discrete scheme. We also prove global existence in 2D for any initial data, provided sufficient divergence damping is included.Comment: 29 pages, no figure

    Algebro-Geometric Solutions of the Boussinesq Hierarchy

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    We continue a recently developed systematic approach to the Bousinesq (Bsq) hierarchy and its algebro-geometric solutions. Our formalism includes a recursive construction of Lax pairs and establishes associated Burchnall-Chaundy curves, Baker-Akhiezer functions and Dubrovin-type equations for analogs of Dirichlet and Neumann divisors. The principal aim of this paper is a detailed theta function representation of all algebro-geometric quasi-periodic solutions and related quantities of the Bsq hierarchy.Comment: LaTeX, 48 page

    Semaphorin4A-Plexin D1 Axis Induces Th2 and Th17 While Represses Th1 Skewing in an Autocrine Manner

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    Semaphorin (Sema)4A is a transmembrane glycoprotein that is elevated in several autoimmune diseases such as systemic sclerosis, rheumatoid arthritis and multiple sclerosis. Sema4A has a key role in the regulation of Thelper Th1 and Th2 differentiation and we recently demonstrated that CD4(+) T cell activation induces the expression of Sema4A. However, the autocrine role of Sema4A on Th cell differentiation remains unknown. Naive Th cells from healthy controls were cell sorted and differentiated into Th1, Th2 and Th17 in the presence or absence of a neutralizing antibody against the Sema4A receptor PlexinD1. Gene expression was determined by quantitative PCR and protein expression by ELISA and flow cytometry. We found that the expression of Sema4A is induced during Th1, Th2 and Th17 differentiation. PlexinD1 neutralization induced the differentiation of Th1 cells, while reduced the Th2 and Th17 skewing. These effects were associated with an upregulation of the transcription factor T-bet by Th1 cells, and to downregulation of GATA3 and RORgammat in Th2 cells and Th17 cells, respectively. Finally, PlexinD1 neutralization regulates the systemic sclerosis patients serum-induced cytokine production by CD4(+) T cells. Therefore, the autocrine Sema4A-PlexinD1 signaling acts as a negative regulator of Th1 skewing but is a key mediator on Th2 and Th17 differentiation, suggesting that dysregulation of this axis might be implicated in the pathogenesis of CD4(+) T cell-mediated diseases

    Universal trapping scaling on the unstable manifold for a collisionless electrostatic mode

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    An amplitude equation for an unstable mode in a collisionless plasma is derived from the dynamics on the two-dimensional unstable manifold of the equilibrium. The mode amplitude ρ(t)\rho(t) decouples from the phase due to the spatial homogeneity of the equilibrium, and the resulting one-dimensional dynamics is analyzed using an expansion in ρ\rho. As the linear growth rate γ\gamma vanishes, the expansion coefficients diverge; a rescaling ρ(t)γ2r(γt)\rho(t)\equiv\gamma^2\,r(\gamma t) of the mode amplitude absorbs these singularities and reveals that the mode electric field exhibits trapping scaling E1γ2|E_1|\sim\gamma^2 as γ0\gamma\rightarrow0. The dynamics for r(τ)r(\tau) depends only on the phase eiξe^{i\xi} where dϵk/dz=ϵkeiξ/2d\epsilon_{{k}} /dz=|{\epsilon_{{k}}}|e^{-i\xi/2} is the derivative of the dielectric as γ0\gamma\rightarrow0.Comment: 11 pages (Latex/RevTex), 2 figures available in hard copy from the Author ([email protected]); paper accepted by Physical Review Letter

    Blocking IL-17: A Promising Strategy in the Treatment of Systemic Rheumatic Diseases

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    Systemic rheumatic diseases are a heterogeneous group of autoimmune disorders that affect the connective tissue, characterized by the involvement of multiple organs, leading to disability, organ failure and premature mortality. Despite the advances in recent years, the therapeutic options for these diseases are still limited and some patients do not respond to the current treatments. Interleukin-17 (IL-17) is a cytokine essential in the defense against extracellular bacteria and fungi. Disruption of IL-17 homeostasis has been associated with the development and progression of rheumatic diseases, and the approval of different biological therapies targeting IL-17 for the treatment of psoriatic arthritis (PsA) and ankylosing spondylitis (AS) has highlighted the key role of this cytokine. IL-17 has been also implicated in the pathogenesis of systemic rheumatic diseases, including systemic lupus erythematosus (SLE), Sjogren's syndrome (SS) and systemic sclerosis (SSc). The aim of this review is to summarize and discuss the most recent findings about the pathogenic role of IL-17 in systemic rheumatic and its potential use as a therapeutic option

    Scaling anomalies in the coarsening dynamics of fractal viscous fingering patterns

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    We analyze a recent experiment of Sharon \textit{et al.} (2003) on the coarsening, due to surface tension, of fractal viscous fingering patterns (FVFPs) grown in a radial Hele-Shaw cell. We argue that an unforced Hele-Shaw model, a natural model for that experiment, belongs to the same universality class as model B of phase ordering. Two series of numerical simulations with model B are performed, with the FVFPs grown in the experiment, and with Diffusion Limited Aggregates, as the initial conditions. We observed Lifshitz-Slyozov scaling t1/3t^{1/3} at intermediate distances and very slow convergence to this scaling at small distances. Dynamic scale invariance breaks down at large distances.Comment: 4 pages, 4 eps figures; to appear in Phys. Rev.

    Normal scaling in globally conserved interface-controlled coarsening of fractal clusters

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    Globally conserved interface-controlled coarsening of fractal clusters exhibits dynamic scale invariance and normal scaling. This is demonstrated by a numerical solution of the Ginzburg-Landau equation with a global conservation law. The sharp-interface limit of this equation is volume preserving motion by mean curvature. The scaled form of the correlation function has a power-law tail accommodating the fractal initial condition. The coarsening length exhibits normal scaling with time. Finally, shrinking of the fractal clusters with time is observed. The difference between global and local conservation is discussed.Comment: 4 pages, 3 eps figure

    Importância prognóstica do alelo CYP2C19*2 após uma síndrome coronária aguda: dados de um centro nacional

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    BACKGROUND: Clopidogrel requires oxidation dependent on the cytochrome P450 enzyme 2C19 (CYP2C19) to form its active metabolite. The importance of loss-of-function alleles (particularly CYP2C19*2, 681G>A) in poor platelet response to clopidogrel is well recognized. OBJECTIVE: To investigate the prevalence and prognostic impact of the CYP2C19*2 allele in a local acute coronary syndrome (ACS) population. METHODS: We performed a prospective, longitudinal study of 95 patients admitted for an ACS between March and October 2009 to a single coronary care unit. Patients aged under 75 who survived hospital stay and for whom clopidogrel was prescribed were included. At discharge, CYP2C19 was genotyped using a commercially available kit. Patients were divided into two groups: Group A (non-carriers, normal metabolizers, CYP2C19*1/*1), n=69; and Group B (carriers, slow metabolizers, CYP2C19*2/*1 or *2/*2), n=26. The primary endpoint was a combined outcome of cardiovascular death, non-fatal myocardial infarction or re-admission for unstable angina; median follow-up was 136.0 (79.0-188.0) days. RESULTS: The median age of the population was 62.0 (51.0-68.0) years, and 83.2% were male. The CYP2C19*2 (A) allele had a frequency of 14.2%. There were no differences between the groups with respect to demographic data or history of cardiovascular disease. Coronary anatomy, left ventricular ejection fraction and renal function were also similar. The groups were also homogenous with respect to GRACE risk score (118.0 (95.0-136.5) vs. 115.0 (96.0-133.0), p=0.68), medical treatment and percutaneous revascularization during hospital stay. Event-free survival was higher for Group A (94.0% vs. 75.0%, log-rank p=0.010). Three readmissions for MI were documented, all in the slow metabolizers group. CONCLUSION: In our ACS population, the CYP2C19*2 allele was a medium-term prognostic marker
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