93 research outputs found

    Indications, Complications, and Retrievals of Inferior Vena Cava Filters in a Colombian Hospital

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    Introduction: Inferior vena cava filters are endovascular devices utilized in clinical practice to mitigate the risk of acute venous thromboembolic disease progression to pulmonary embolism in cases of absolute contraindications to anticoagulation. Currently, there are no reports on the experience of using such devices in Colombia. Objective: To assess the indications, practices, retrieval rates, and complications of inferior vena cava filters in a university hospital in Colombia. Methods: A retrospective study was conducted at a tertiary-level university hospital in Colombia. Patients who had undergone inferior vena cava filter implantation were included, with exclusion of those with essential data missing for analysis. Descriptive statistics and Student’s t-test were performed for group comparisons. Results: A total of 196 patients with acute venous thromboembolic disease who had undergone inferior vena cava filter implantation were included. None of the patients received the device as primary prophylaxis. Filter-related complications occurred in 13 patients, and retrieval was considered for 118 patients, of whom 108 retrievals were successful. Among the included oncology patients who received an inferior vena cava filter, 36 underwent retrieval attempts, achieving success in 32 cases (88.8%). Conclusions: This study revealed that the most common indications for inferior vena cava filter implantation were the need for surgery, acute bleeding or bleeding risk, and catheter-guided local thrombolysis. The most frequent complication was acute inferior vena cava thrombosis and filter tilting. Inferior vena cava filter retrieval was successful in the majority of attempted cases

    Tecnología generada para el cultivo y producción rentable de plátano en la zona cafetera central colombiana: informe técnico resumen

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    La importanciadel cultivo dél plátano a nivel del Departamento del Quindío y del país en general crece año tras año. Tanto desde el punto de vista social como económico. A pesar de la importancia, su explotación afronta una serie de problemas relacionados con técnicas de producción, que junto con la presencia de plagas y enfermedades influyen preponderantemente no sólo sobre el rendimiento y su calidad; sino también en el incremento de nuevas áreas de siembra.Plátano-Musa sapientu

    Power Quality Indices Estimation Platform

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    En este artículo se presenta una plataforma interactiva para la estimación de índices de calidad de la potencia de sistemas eléctricos monofásicos, en conformidad con el estándar IEEE 1459-2010. La plataforma PQanalizador se desarrolló con el objetivo de apoyar actividades de docencia e investigación en calidad de la energía eléctrica. La plataforma estima los índices a partir de señales de voltaje y corriente usando tres diferentes algoritmos basados en la transformada rápida de Fourier (FFT), la transformada Wavelet Packet (WPT) y la metodología de mínimos cuadrados. Los resultados muestran que los algoritmos implementados son eficientes para la estimación de los índices de calidad de la potencia y que la plataforma puede ser usada según los objetivos propuestos.An interactive platform for estimating the quality indices in single phase electric power systems is presented. It meets the IEEE 1459-2010 standard recommendations. The platform was developed in order to support teaching and research activities in electric power quality. The platform estimates the power quality indices from voltage and current signals using three different algorithms based on fast Fourier transform (FFT), wavelet packet transform (WPT) and least squares method. The results show that the algorithms implemented are efficient for estimating the quality indices of the power and the platform can be used according to the objectives established.

    Implicaciones metodológicas e inconsistencias de la Tercera Comunicación Nacional sobre Cambio Climático de Colombia

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    Las Comunicaciones Nacionales sobre Cambio Climático (CNCC) son un mecanismo para que los países informen sus avances en mitigación y adaptación, y constituyen uno de los elementos de base para la política sobre cambio climático a escala nacional. Colombia ha emitido tres CNCC. La tercera plantea un escenario que considera las proyecciones de diversos modelos incluidos en la quinta fase del Proyecto de Comparación de Modelos Acoplados (Coupled Model Intercomparison Project, CMIP), el cual se estima como el promedio de las proyecciones correspondientes a las cuatro trayectorias de concentración representativa (Representative Concentration Pathways,RCP) presentadas en el quinto reporte de evaluación del Panel Intergubernamental sobre Cambio Climático. Cada una de estas RCP representa una trayectoria de concentración de gases de efecto invernadero (GEI) para un escenario particular de crecimiento poblacional, económico y tecnológico que conduce a una posible trayectoria de evolución del sistema climático. En este estudio se comparan las proyecciones presentadas en la Tercera CNCC con las obtenidas directamente de los modelos empleados. Nuestros resultados demuestran que al utilizarse un promedio de RCP se pierden escenarios alternos que podrían ser importantes a la hora de considerar posibles futuros diferentes y anulan la utilidad de plantear diversas trayectorias de emisiones de GEI. Más aun, una comparación entre la Segunda y la Tercera CNCC muestra proyecciones de precipitación opuestas para diferentes regiones del país, lo cual es de particular importancia, pues el escenario de cambio climático planteado en la Tercera CNCC sirve de referencia para la toma de decisiones en materia de cambio climático a nivel nacional

    Increased power by harmonizing structural MRI site differences with the ComBat batch adjustment method in ENIGMA

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    A common limitation of neuroimaging studies is their small sample sizes. To overcome this hurdle, the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) Consortium combines neuroimaging data from many institutions worldwide. However, this introduces heterogeneity due to different scanning devices and sequences. ENIGMA projects commonly address this heterogeneity with random-effects meta-analysis or mixed-effects mega-analysis. Here we tested whether the batch adjustment method, ComBat, can further reduce site-related heterogeneity and thus increase statistical power. We conducted random-effects meta-analyses, mixed-effects mega-analyses and ComBat mega-analyses to compare cortical thickness, surface area and subcortical volumes between 2897 individuals with a diagnosis of schizophrenia and 3141 healthy controls from 33 sites. Specifically, we compared the imaging data between individuals with schizophrenia and healthy controls, covarying for age and sex. The use of ComBat substantially increased the statistical significance of the findings as compared to random-effects meta-analyses. The findings were more similar when comparing ComBat with mixed-effects mega-analysis, although ComBat still slightly increased the statistical significance. ComBat also showed increased statistical power when we repeated the analyses with fewer sites. Results were nearly identical when we applied the ComBat harmonization separately for cortical thickness, cortical surface area and subcortical volumes. Therefore, we recommend applying the ComBat function to attenuate potential effects of site in ENIGMA projects and other multi-site structural imaging work. We provide easy-to-use functions in R that work even if imaging data are partially missing in some brain regions, and they can be trained with one data set and then applied to another (a requirement for some analyses such as machine learning)

    Large-scale analysis of structural brain asymmetries in schizophrenia via the ENIGMA consortium

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    BACKGROUND Left-right asymmetry is an important organizing feature of the healthy brain that may be altered in schizophrenia, but most studies have used relatively small samples and heterogeneous approaches, resulting in equivocal findings. We carried out the largest case-control study of structural brain asymmetries in schizophrenia (N = 11,095), using a single image analysis protocol. METHODS We included T1-weighted data from 46 datasets (5,080 affected individuals and 6,015 controls) from the ENIGMA Consortium. Asymmetry indexes were calculated for global and regional cortical thickness, surface area, and subcortical volume measures. Differences of asymmetry were calculated between affected individuals and controls per dataset, and effect sizes were meta-analyzed across datasets. Analyses were also performed with respect to the use of antipsychotic medication and other clinical variables, as well as age and sex. Case-control differences in a multivariate context were assessed in a subset of the data (N = 2,029). RESULTS Small average differences between cases and controls were observed for asymmetries in cortical thickness, specifically of the rostral anterior cingulate (d = −0.08, pFDR = 0.047) and the middle temporal gyrus (d = −0.07, pFDR = 0.048), both driven primarily by thinner cortices in the left hemisphere in schizophrenia. These asymmetries were not significantly associated with the use of antipsychotic medication or other clinical variables. Older individuals with schizophrenia showed a stronger average leftward asymmetry of pallidum volume than older controls (d = 0.08, pFDR = 9.0 × 10−3). The multivariate analysis revealed that 7% of the variance across all structural asymmetries was explained by case-control status (F = 1.87, p = 1.25 × 10−5). CONCLUSIONS Altered trajectories of asymmetrical brain development and/or lifespan asymmetry may contribute to schizophrenia pathophysiology. Small case-control differences of brain macro-structural asymmetry may manifest due to more substantial differences at the molecular, cytoarchitectonic or circuit levels, with functional relevance for lateralized cognitive processes

    Widespread white matter microstructural differences in schizophrenia across 4322 individuals:Results from the ENIGMA Schizophrenia DTI Working Group

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    The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.Molecular Psychiatry advance online publication, 17 October 2017; doi:10.1038/mp.2017.170

    Country-level gender inequality is associated with structural differences in the brains of women and men

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    Gender inequality across the world has been associated with a higher risk to mental health problems and lower academic achievement in women compared to men. We also know that the brain is shaped by nurturing and adverse socio-environmental experiences. Therefore, unequal exposure to harsher conditions for women compared to men in gender-unequal countries might be reflected in differences in their brain structure, and this could be the neural mechanism partly explaining women's worse outcomes in gender-unequal countries. We examined this through a random-effects meta-analysis on cortical thickness and surface area differences between adult healthy men and women, including a meta-regression in which country-level gender inequality acted as an explanatory variable for the observed differences. A total of 139 samples from 29 different countries, totaling 7,876 MRI scans, were included. Thickness of the right hemisphere, and particularly the right caudal anterior cingulate, right medial orbitofrontal, and left lateral occipital cortex, presented no differences or even thicker regional cortices in women compared to men in gender-equal countries, reversing to thinner cortices in countries with greater gender inequality. These results point to the potentially hazardous effect of gender inequality on women's brains and provide initial evidence for neuroscience-informed policies for gender equality

    Large-scale analysis of structural brain asymmetries in schizophrenia via the ENIGMA consortium

    Get PDF
    Left-right asymmetry is an important organizing feature of the healthy brain that may be altered in schizophrenia, but most studies have used relatively small samples and heterogeneous approaches, resulting in equivocal findings. We carried out the largest case-control study of structural brain asymmetries in schizophrenia, using MRI data from 5,080 affected individuals and 6,015 controls across 46 datasets in the ENIGMA consortium, using a single image analysis protocol. Asymmetry indexes were calculated for global and regional cortical thickness, surface area, and subcortical volume measures. Differences of asymmetry were calculated between affected individuals and controls per dataset, and effect sizes were meta-analyzed across datasets. Small average case-control differences were observed for thickness asymmetries of the rostral anterior cingulate and the middle temporal gyrus, both driven by thinner left-hemispheric cortices in schizophrenia. Analyses of these asymmetries with respect to the use of antipsychotic medication and other clinical variables did not show any significant associations. Assessment of age- and sex-specific effects revealed a stronger average leftward asymmetry of pallidum volume between older cases and controls. Case-control differences in a multivariate context were assessed in a subset of the data (N = 2,029), which revealed that 7% of the variance across all structural asymmetries was explained by case-control status. Subtle case-control differences of brain macro-structural asymmetry may reflect differences at the molecular, cytoarchitectonic or circuit levels that have functional relevance for the disorder. Reduced left middle temporal cortical thickness is consistent with altered left-hemisphere language network organization in schizophrenia
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