1,140 research outputs found

    Advances in MR Imaging of Leukodystrophies

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    A Systematic Review and Meta-Analysis

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    We evaluated the relevance of plasma homocysteine (HC) and the TT genotype of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism (rs1801133) in sickle cell disease (SCD) and associated vaso-occlusive crisis (VOC) and ischemic stroke (IS). We identified in Embase and Medline 22 studies on plasma HC and 22 on MTHFR genotypes. Due to age-related HC differences, adult and paediatric SCD were separated: 879 adult SCD and 834 controls (CTR) yielded a neutral effect size; 427 paediatric SCD and 625 CTR favoured SCD (p = 0.001) with wide heterogeneity (I2 = 95.5%) and were sub-grouped by country: six studies (Dutch Antilles n = 1, USA n = 5) yielded a neutral effect size, four (India n = 1, Arab countries n = 3) favoured SCD (p < 0.0001). Moreover, 249 SCD in VOC and 419 out of VOC yielded a neutral effect size. The pooled prevalence of the MTHFR TT genotype in 267 SCD equalled that of 1199 CTR (4.26% vs. 2.86%, p = 0.45), and in 84 SCD with IS equalled that of 86 without IS (5.9% vs. 3.7%, p = 0.47); removal of one paediatric study yielded a significant effect size (p = 0.006). Plasma HC in paediatric SCD from Middle East and India was higher, possibly due to vitamin deficiencies. Despite its low prevalence in SCD, the MTHFR TT genotype relates to adult IS.publishersversionpublishe

    A Systematic Review and Exploratory Meta-Analysis

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    The relationship between antiphospholipid antibodies (aPL) and sickle cell disease (SCD) has never been systematically addressed. Our aim was to evaluate potential links between SCD and aPL in all age groups. EMBASE/PubMed was screened from inception to May 2020 and Peto odds ratios for rare events were calculated. The pooled prevalence (PP) of IgG anticardiolipin antibodies (aCL) was higher in individuals with SCD than in controls (27.9% vs 8.7%, P < 0.0001), that of IgM aCL was similar in the two groups (2.9% vs 2.7%); only individuals with SCD were positive for lupus anticoagulant (LA) (7.7% vs 0%, P < 0.0001). The PP of leg ulcers was similar between aPL positive and negative individuals (44% vs 53%) and between patients in acute crisis and stable patients (5.6% vs 7.3%). Reporting of aPL as a binary outcome and not as a titer precluded further interpretation. The results indicate that a prospective case-control study with serial measurements of a panel of aPL in SCD patients might be warranted, in order to understand further the possible pathogenic role of aPL in SCD.publishersversionpublishe

    Gibrat’s law and the change in artificial land use within and between European cities

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    editorial reviewedSeen from a satellite, observing land use in the daytime or at night, most cities have circular shapes, organised around a city centre. A radial analysis of artificial land use growth is conducted in order to understand what the recent changes in urbanisation are across Europe and how it relates to city size. We focus on the most fundamental differentiation regarding urban land use: has it been artificialised for human uses (residence or roads for instance) or is it natural, or at least undeveloped? Using spatially detailed data from the EU Copernicus Urban Atlas, profiles of artificial land use (ALU) are calculated and compared between two years, 2006 and 2012. Based on the homothety of urban forms found by Lemoy and Caruso (2018), a simple scaling law is used to compare the internal structure of cities after controlling for population size. We firstly show that when using the functional urban area (FUA) definition of cities, a kind of Gibrat’s law for land use appears to hold. However, when we examine cities internally, this is no longer clear as there are differences on average between city size categories. We also look at further city groupings using regions and topography to show that artificial land use growth across European cities is not homogeneous. Our findings have important implications relative to the sustainability of cities as this evidence is pointing towards increasing urban sprawl and stagnant growth in urban centres across cities of all sizes. It also has theoretical implications on the nature of sprawl and its scaling with city size

    On the heterogeneity of urban expansion profiles in Europe

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    The difference of a city's artificial land use (ALU) radial profile to the average ALU profile is examined for 585 European cities. Using Urban Atlas 2012 data, a radial (or monocentric) approach is used to calculate a city's land use profile in relation to distance to the city centre. A scaling law is used which controls for city size and population. As a consequence, cities of varying degrees of size can be contrasted in a comparable way. Utilising the mean ALU profile for the entire sample of 585 cities, the difference to the mean profile is calculated for each city. Using these differences allows us to examine heterogeneity of the ALU across European cities but also examine these differences within cities. We utilise city groupings by city size and country to attempt to understand these differences. Combining Urban Atlas and Corine Land Cover data, the impact of water on the ALU profiles is examined. A city classification is also introduced which considers the difference to the average curve. Ordering methods are used to visualise cities within these classifications. Results highlight the level of heterogeneity between cities. Removing water, we can see that the cities with the highest levels of water have a higher level of ALU on average. Spain and France are found to have contrasting levels of ALU, Spanish cities having below average ALU and France above average. Using seriation techniques enables us to group and order cities into a typology which can be used to benchmark cities

    Epidemiology of patients presenting to the emergency centre of Princess Marina Hospital in Gaborone, Botswana

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    Emergency medicine is a newly recognized specialty in Botswana and the country launched an emergency medicine residency in January 2011. Data regarding the practice of emergency medicine in Botswana are limited. This study reviewed 1 year of patient presentations to the emergency centre of Princess Marina Hospital, the country’s main referral hospital located in the capital city, Gaborone. Methods: Epidemiologic data of all patients presenting to the emergency centre between May 2010 and April 2011 were extracted into a database. The diagnoses of a random sample of patient presentations were coded using the categories outlined by the Clinical Classifications Software (CCS) for ICD-10. For ease of analysis, several CCS categories were grouped together for subsequent analysis. Results: 24,905 patient encounters were recorded during the study period. A large proportion of patients were aged between 25 and 50 years old. 20% of patients presented with a traumatic injury. The most common diagnoses across all ages included trauma, pregnancy complications, gastrointestinal disorders, and pneumonia. Conclusion: These results can inform the development of emergency medicine education and acute care systems in Botswana

    Institutionalizing health technology assessment in Ethiopia: Seizing the window of opportunity

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    Ethiopia’s commitment to achieving universal health coverage (UHC) requires an efficient and equitable health priority-setting practice. The Ministry of Health aims to institutionalize health technology assessment (HTA) to support evidence-based decision making. This commentary highlights key considerations for successful formulation, adoption, and implementation of HTA policies and practices in Ethiopia, based on a review of international evidence and published normative principles and guidelines. Stakeholder engagement, transparent policymaking, sustainable financing, workforce education, and political economy analysis and power dynamics are critical factors that need to be considered when developing a national HTA roadmap and implementation strategy. To ensure ownership and sustainability of HTA, effective stakeholder engagement and transparency are crucial. Regulatory embedding and sustainable financing ensure legitimacy and continuity of HTA production, and workforce education and training are essential for conducting and interpreting HTA. Political economy analysis helps identify opportunities and constraints for effective HTA implementation. By addressing these considerations, Ethiopia can establish a well-designed HTA system to inform evidence-based and equitable resource allocation toward achieving UHC and improving health outcomes.publishedVersio
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