190 research outputs found
Thrombolysis in Patients Aged over 80 Years Is Equally Effective and Safe
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
The amplitude equation for an unstable electrostatic wave in a multi-species
Vlasov plasma has been derived. The dynamics of the mode amplitude is
studied using an expansion in ; in particular, in the limit
, the singularities in the expansion coefficients are
analyzed to predict the asymptotic dependence of the electric field on the
linear growth rate . Generically , as
, but in the limit of infinite ion mass or for
instabilities in reflection-symmetric systems due to real eigenvalues the more
familiar trapping scaling 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
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 energy estimate. However,
through use of new 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
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
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
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 decouples from the phase due to the
spatial homogeneity of the equilibrium, and the resulting one-dimensional
dynamics is analyzed using an expansion in . As the linear growth rate
vanishes, the expansion coefficients diverge; a rescaling
of the mode amplitude absorbs these
singularities and reveals that the mode electric field exhibits trapping
scaling as . The dynamics for
depends only on the phase where is the derivative of the dielectric as
.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
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
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 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
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
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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