74 research outputs found

    A glaucoma polygenic risk score strongly associated with disease prediction and treatment intensity

    Get PDF
    This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.Jamie E Craig; Ayub Qassim; Xikun Han; Mark Hassall; Robert James Casson; Stuart L Graham; David A Mackey; Colin Willoughby; Kathryn P Burdon; John Landers; Emmanuelle Souzeau; Janey L Wiggs; Alex W Hewitt; Stuart MacGrego

    Analysis combining correlated glaucoma traits identifies five new risk loci for open-angle glaucoma

    Get PDF
    Open-angle glaucoma (OAG) is a major cause of blindness worldwide. To identify new risk loci for OAG, we performed a genome-wide association study in 3,071 OAG cases and 6,750 unscreened controls, and meta-analysed the results with GWAS data for intraocular pressure (IOP) and optic disc parameters (the overall meta-analysis sample size varying between 32,000 to 48,000 participants), which are glaucoma-related traits. We identified and independently validated four novel genome-wide significant associations within or near MYOF and CYP26A1, LINC02052 and CRYGS, LMX1B, and LMO7 using single variant tests, one additional locus (C9) using gene-based tests, and two genetic pathways - "response to fluid shear stress" and "abnormal retina morphology" - in pathway-based tests. Interestingly, some of the new risk loci contribute to risk of other genetically-correlated eye diseases including myopia and age-related macular degeneration. To our knowledge, this study is the first integrative study to combine genetic data from OAG and its correlated traits to identify new risk variants and genetic pathways, highlighting the future potential of combining genetic data from genetically-correlated eye traits for the purpose of gene discovery and mapping.Puya Gharahkhani … Robert Casson … et al. [and The NEIGHBORHOOD consortium]

    Prevalence and causes of vision loss in Latin America and the Caribbean in 2015: magnitude, temporal trends and projections

    Get PDF
    OBJECTIVE: To estimate the prevalence and causes of blindness and vision impairment for distance and near in Latin America and the Caribbean (LAC) in 2015, and to forecast trends to 2020. METHODS: A meta-analysis from a global systematic review of cross-sectional, population-representative studies from published and unpublished sources from 1980 to 2014 included in the Global Vision Database. RESULTS: In 2015, across LAC, we estimate age-standardised prevalence to be 0.38% in all ages and 1.56% in those over age 50 for blindness, 2.06% in all ages and 7.86% in those over age 50 for moderate and severe vision impairment (MSVI), 1.89% in all ages and 6.93% in those over age 50 for mild vision impairment, and 39.59% in all ages and 45.27% in those over 50 for near vision impairment. We estimate that in 2015, 123.26 million persons were vision impaired; of those 2.34 million blind, 12.46 million with MSVI, 11.34 million mildly impaired and 97.12 million had near vision impairment. Cataract is the most common cause of blindness. Under- corrected refractive-error is the most common cause of vision impairment. CONCLUSIONS: Increasing granularity in prevalence estimates across all levels of vision loss suggest that one in five persons across LAC had some degree of vision loss in 2015. The absolute numbers of persons with vision impairment are increasing, while the age-standardised prevalence is decreasing. All countries should conduct epidemiologic studies to establish accurate national estimates and trends of vision impairment. Universal eye health services must be included in universal health coverage reforms to address fragmentation and segmentation of health care across the region

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

    Get PDF
    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

    Densidade, tamanho e distribuição estomática em 35 espécies de árvores na Amazônia Central

    Get PDF
    Stomata are turgor-operated valves that control water loss and CO2 uptake during photosynthesis, and thereby water relation and plant biomass accumulation is closely related to stomatal functioning. The aims of this work were to document how stomata are distributed on the leaf surface and to determine if there is any significant variation in stomatal characteristics among Amazonian tree species, and finally to study the relationship between stomatal density (S D) and tree height. Thirty five trees (>17 m tall) of different species were selected. Stomatal type, density (S D), size (S S) and stomatal distribution on the leaf surface were determined using nail polish imprints taken from both leaf surfaces. Irrespective of tree species, stomata were located only on the abaxial surface (hypostomaty), with large variation in both S D and S S among species. S D ranged from 110 mm-2 in Neea altissima to 846 mm-2 in Qualea acuminata. However, in most species S D ranges between 271 and 543 mm-2, with a negative relationship between S D and S S. We also found a positive relationship between S D and tree height (r² = 0.14, p 17 m de altura) de diferentes espécies foram selecionadas. Tipo de complexo estomático, S D, tamanho (S S) e distribuição na superfície foliar foram determinados utilizando impressões de ambas as superfícies foliares com esmalte incolor. Independente da espécie, os estômatos foram encontrados apenas na superfície abaxial (hipoestomatia) com ampla variação na S D e no S S entre espécies. A densidade estomática variou de 110 mm-2 em Neea altissima a 846 mm-2 em Qualea acuminata. Entretanto, a maioria das espécies apresentou S D entre 271 e 543 mm-2, com uma relação negativa entre S D e S S. Observou-se uma relação positiva entre S D e altura arbórea (r² = 0.14, p < 0.01), não havendo relação entre S D e espessura foliar. Os tipos estomáticos mais comuns foram: anomocíticos (37%), seguidos de paracíticos (26%) e anisocíticos (11%). Concluiu-se que em espécies da Amazônia, a distribuição de estômatos na superfície foliar está mais relacionada a fatores genéticos de cada espécie do que a variações ambientais. Entretanto, S D é fortemente influenciada por fatores ambientais concernentes à altura da árvore
    corecore