1,720,979 research outputs found
Association between blood pressure variability and outcomes after endovascular thrombectomy for acute ischemic stroke: An individual patient data meta-analysis
No full textIntroduction: Data on the association between blood pressure variability (BPV) after endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) and outcomes are limited. We sought to identify whether BPV within the first 24 hours post EVT was associated with key stroke outcomes. Methods: We combined individual patient-data from five studies among AIS-patients who underwent EVT, that provided individual BP measurements after the end of the procedure. BPV was estimated as either systolic-BP (SBP) standard deviation (SD) or coefficient of variation (CV) over 24 h post-EVT. We used a logistic mixed-effects model to estimate the association [expressed as adjusted odds ratios (aOR)] between tertiles of BPV and outcomes of 90-day mortality, 90-day death or disability [modified Rankin Scale-score (mRS) > 2], 90-day functional impairment (⩾1-point increase across all mRS-scores), and symptomatic intracranial hemorrhage (sICH), adjusting for age, sex, stroke severity, co-morbidities, pretreatment with intravenous thrombolysis, successful recanalization, and mean SBP and diastolic-BP levels within the first 24 hours post EVT. Results: There were 2640 AIS-patients included in the analysis. The highest tertile of SBP-SD was associated with higher 90-day mortality (aOR:1.44;95% CI:1.08–1.92), 90-day death or disability (aOR:1.49;95% CI:1.18–1.89), and 90-day functional impairment (adjusted common OR:1.42;95% CI:1.18–1.72), but not with sICH (aOR:1.22;95% CI:0.76–1.98). Similarly, the highest tertile of SBP-CV was associated with higher 90-day mortality (aOR:1.33;95% CI:1.01–1.74), 90-day death or disability (aOR:1.50;95% CI:1.19–1.89), and 90-day functional impairment (adjusted common OR:1.38;95% CI:1.15–1.65), but not with sICH (aOR:1.33;95% CI:0.83–2.14). Conclusions: BPV after EVT appears to be associated with higher mortality and disability, independently of mean BP levels within the first 24 h post EVT. BPV in the first 24 h may be a novel target to improve outcomes after EVT for AIS
Blood Pressure Trajectories and Outcomes After Endovascular Thrombectomy for Acute Ischemic Stroke
No full textBACKGROUND:
Data on systolic blood pressure (SBP) trajectories in the first 24 hours after endovascular thrombectomy (EVT) in acute ischemic stroke are limited. We sought to identify these trajectories and their relationship to outcomes.
METHODS:
We combined individual-level data from 5 studies of patients with acute ischemic stroke who underwent EVT and had individual blood pressure values after the end of the procedure. We used group-based trajectory analysis to identify the number and shape of SBP trajectories post-EVT. We used mixed effects regression models to identify associations between trajectory groups and outcomes adjusting for potential confounders and reported the respective adjusted odds ratios (aORs) and common odds ratios.
RESULTS:
There were 2640 total patients with acute ischemic stroke included in the analysis. The most parsimonious model identified 4 distinct SBP trajectories, that is, general directional patterns after repeated SBP measurements: high, moderate-high, moderate, and low. Patients in the higher blood pressure trajectory groups were older, had a higher prevalence of vascular risk factors, presented with more severe stroke syndromes, and were less likely to achieve successful recanalization after the EVT. In the adjusted analyses, only patients in the high-SBP trajectory were found to have significantly higher odds of early neurological deterioration (aOR, 1.84 [95% CI, 1.20–2.82]), intracranial hemorrhage (aOR, 1.84 [95% CI, 1.31–2.59]), mortality (aOR, 1.75 [95% CI, 1.21–2.53), death or disability (aOR, 1.63 [95% CI, 1.15–2.31]), and worse functional outcomes (adjusted common odds ratio,1.92 [95% CI, 1.47–2.50]).
CONCLUSIONS:
Patients follow distinct SBP trajectories in the first 24 hours after an EVT. Persistently elevated SBP after the procedure is associated with unfavorable short-term and long-term outcomes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Enhancing motor performance in the healthy and Parkinsonian brain: adaptation, oscillations, and electrical stimulation
Full text linkParkinson's disease (PD) is characterized by debilitating impairments in motor control arising from pathophysiological alterations in basal ganglia circuitry and function. In this research thesis two main approaches, namely electrical recording and stimulation, are combined in order to better understand motor performance in Parkinson's disease and ways it might be improved. Three main types of motor behaviors are studied: discrete ballistic movement, repetitive movement, and motor adaptation. First, deep brain stimulation (DBS) of the subthalamic nucleus (STN) was shown to improve the velocity of discrete, ballistic movements in PD. The neural correlates of ballistic movements were then studied by recording from the STN of PD patients, revealing onset of beta-range desynchronization prior to, and gamma-range frequency synchronization during, performance of fast arm reaches. To determine a causal role for these oscillatory frequencies in motor behavior, the motor cortex of healthy humans was stimulated at either beta or gamma frequency during a 'go/no-go' grip force task. Beta stimulation resulted in slower force generation on 'go' trials but enhanced inhibition during 'no-go' trials, whereas gamma stimulation resulted in faster force generation on 'go' trials. Second, STN DBS resulted in improved repetitive tapping performance in PD patients through a reduction in variability. Recordings from the STN demonstrated that repetitive movement was accompanied by a substantial and persistent suppression of beta oscillatory activity. Third, Parkinson's patients were tested on a motor adaptation task, revealing intact learning but impaired retention of a visuomotor rotation. Application of direct current stimulation of the motor cortex resulted in enhanced adaptation during both learning and retention in PD patients and healthy controls. These results causally implicate the basal ganglia and oscillatory activity in motor control, provide insight into the neuronal mechanisms of motor performance and adaptation, and demonstrate promising new avenues for enhancing motor control in Parkinson's disease
Activity limitations, use of assistive devices, and mortality and clinical events in 25 high-income, middle-income, and low-income countries: an analysis of the PURE study
No full textSY cuenta con el apoyo de la presidenta de la Heart and Stroke Foundation de Ontario, donada por Marion W Burke. El estudio PURE es un estudio iniciado por investigadores y financiado por el Instituto de Investigación en Salud de la Población, el Instituto de Investigación en Ciencias de la Salud de Hamilton, los Institutos Canadienses de Investigación en Salud, la Fundación Heart and Stroke de Ontario, el apoyo de la Estrategia de Investigación Orientada al Paciente de los Institutos Canadienses de Investigación en Salud, a través de la Unidad de Apoyo SPOR de Ontario y el Ministerio de Salud y Cuidados a Largo Plazo de Ontario y a través de subvenciones ilimitadas de varias compañías farmacéuticas, con importantes contribuciones de AstraZeneca (Canadá), Sanofi-Aventis. (Francia y Canadá), Boehringer Ingelheim (Alemania y Canadá), Servier y GlaxoSmithKline, y contribuciones adicionales de Novartis y King Pharma. El estudio también fue financiado por varias organizaciones nacionales o locales en los países participantes: Argentina: Fundación ECLA (Estudios Clínicos Latino América), Bangladesh: Universidad Independiente, Bangladesh y Mitra and Associates, Brasil: Hospital Alemão Oswaldo Cruz, São Paulo, Brasil, Canadá: subvención sin restricciones de Dairy Farmers of Canada y el National Dairy Council (EE.UU.), la Agencia de Salud Pública de Canadá y la Red Champlain de Prevención de Enfermedades Cardiovasculares, Chile: Universidad de La Frontera [DI13-PE11/EXD05-0003] , China: Centro Nacional de Enfermedades Cardiovasculares y Centro de Investigación ThinkTank para el Desarrollo de la Salud, Colombia: Colciencias (beca 6566-04-18062 y beca 6517-777-58228), India: Consejo Indio de Investigaciones Médicas, Malasia: Ministerio de Ciencia, Tecnología e Innovación de Malasia (número de subvención: 100-IRDC/BIOTEK 16/6/21 [13/2007] y 07-05-IFN-BPH 010), Ministerio de Educación Superior de Malasia (número de subvención: 600-RMI/LRGS/5/3 [2/2011]), Universiti Teknologi MARA, Sector de Bioestadística y Repositorio de Datos, Instituto Nacional de Salud, Setia Alam por el servicio de enlace de datos y Departamento de Registro Nacional (JPN) por su disposición a compartir sus registros de mortalidad con fines de investigación, Universiti Kebangsaan Malaysia (UKM-Hejim-Komuniti-15-2010), territorio palestino ocupado: Organismo de Obras Públicas y Socorro de las Naciones Unidas para los Refugiados de Palestina en el Cercano Oriente, territorio palestino ocupado, Centro Internacional de Investigaciones para el Desarrollo, Canadá, Filipinas: Consejo Filipino para la Investigación y el Desarrollo en Salud, Polonia: Ministerio polaco de Ciencia y Educación Superior (número de subvención: 290/W-PURE/2008/0), Universidad Médica de Wroclaw, Arabia Saudita: Asociación Saudita del Corazón, Hospital Dr. Mohammad Alfagih, Decanato de Investigación Científica de la Universidad Rey Saud (número de grupo de investigación: RG-1436-013), Riad, Cátedra Saleh Hamza Serafi de Investigación de Enfermedades Coronarias, Universidad Umm AlQura, La Meca, Arabia Saudita, Sudáfrica: Programa de Desarrollo Alternativo de la Universidad del Noroeste, Sudáfrica y los Países Bajos, Fundación Nacional de Investigación, Consejo de Investigación Médica de Sudáfrica, Facultad de Ciencias Comunitarias y de la Salud, Suecia: subvenciones del Estado sueco en virtud de un acuerdo entre el Gobierno sueco y los consejos de condado sobre apoyo económico a la investigación y la formación de médicos (ALFGBG-966211), la Fundación Sueca del Corazón y los Pulmones (2021-0345), el Consejo Sueco de Investigación (2018-02527), Seguros AFA (16-0334), y el Consejo Sueco para la Salud, la Vida Laboral y el Bienestar [2013-0325], Turkiye: Sociedad del Síndrome Metabólico, Emiratos Árabes Unidos: Premio Sheikh Hamdan Bin Rashid Al Maktoum de Ciencias Médicas y Autoridad Sanitaria de Dubai, Dubai. En el apéndice (págs. 28 y 29) se muestran más detalles sobre la financiación y los países e instituciones participantes, así como sobre el personal colaborador
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
