148 research outputs found

    A polymorphism of a platelet glycoprotein receptor as an inherited risk factor for coronary thrombosis.

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    BACKGROUND: Platelet glycoprotein IIb/IIIa is a membrane receptor for fibrinogen and von Willebrand factor, and it has an important role in platelet aggregation. It is known to be involved in the pathogenesis of acute coronary syndromes. Previously, we found a high frequency of a particular polymorphism, PlA2, of the gene encoding glycoprotein IIIa in kindreds with a high prevalence of premature myocardial infarction. METHODS: To investigate the relation between the PlA2 polymorphism and acute coronary syndromes, we conducted a case-control study of 71 case patients with myocardial infarction or unstable angina and 68 inpatient controls without known heart disease. The groups were matched for age, race, and sex. We used two methods to determine the PlA genotype: reverse dot blot hybridization and allele-specific restriction digestion. RESULTS: The prevalence of PlA2 was 2.1 times higher among the case patients than among the controls (39.4 percent vs. 19.1 percent, P=0.01). In a subgroup of patients whose disease began before the age of 60 years, the prevalence of PlA2 was 50 percent, a value that was 3.6 times that among control subjects under 60 years of age (13.9 percent, P=0.002). Among subjects with the PlA2 polymorphism, the odds ratio for having a coronary event was 2.8 (95 percent confidence interval, 1.2 to 6.4). In the patients less than 60 years of age at the onset of disease, the odds ratio was 6.2 (95 percent confidence interval, 1.8 to 22.4). CONCLUSIONS: We observed a strong association between the PlA2 polymorphism of the glycoprotein IIIa gene and acute coronary thrombosis, and this association was strongest in patients who had had coronary events before the age of 60 years

    Isolated Scaphoid Dislocation From Low-Energy Wrist Trauma

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    Isolated scaphoid dislocation is an extremely rare injury typically caused by high-energy trauma. We present the first observed case of isolated scaphoid dislocation resulting from a non-traumatic injury of the wrist in power-grip tension in a patient with a questionable history of Marfan Syndrome. A 20-yearold right-hand dominant man presented to the emergency department with right wrist pain and deformation after carrying a table. The patient reported a possible history of Marfan Syndrome, but it had never been definitively diagnosed. Imaging revealed radial dislocation of the scaphoid. Bedside closed reduction was performed followed by outpatient ligament reconstruction with return to normal activities at 6 months. Early diagnosis and management lead to an improved prognosis for isolated scaphoid dislocation. Regardless of patient history or mechanism of injury, treatment options include closed reduction, percutaneous fixation, and/or open reduction with internal fixation and ligamentous reconstructio

    Comparison of Patient- and Practitioner-Reported Toxic Effects Associated With Chemoradiotherapy for Head and Neck Cancer

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    Agreement between patient- and practitioner-reported toxic effects during chemoradiotherapy for head and neck cancer is unknown. To compare patient-reported symptom severity and practitioner-reported toxic effects among patients receiving chemoradiotherapy for head and neck cancer. Forty-four patients participating in a phase 2 trial of deintensified chemoradiotherapy for oropharyngeal carcinoma were included in the present study (conducted from February 8, 2012, to March 2, 2015). Most treatment (radiotherapy, 60 Gy, with concurrent weekly administration of cisplatin, 30 mg/m2) was administered at academic medical centers. Included patients had no prior head and neck cancers, were 18 years or older, and had a smoking history of 10 pack-years or less or more than 10 pack-years but 30 pack-years or less and abstinent for the past 5 years. Cancer status was untreated human papillomavirus or p16-positive squamous cell carcinoma of the oropharynx or unknown head and neck primary site; and cancer staging was category T0 to T3, category N0 to N2c, M0, and Eastern Cooperative Oncology Group performance status 0 to 1. Baseline, weekly, and posttreatment toxic effects were assessed by physicians or nurse practitioners using National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE), version 4.0. Patient-reported symptom severity was measured using the Patient-Reported Outcomes version of the CTCAE (PRO-CTCAE). Descriptive statistics were used to characterize raw agreement between CTCAE grades and PRO-CTCAE severity ratings. Baseline, weekly, and posttreatment toxic effects assessed using CTCAE, version 4.0, and PRO-CTCAE. Raw agreement indices between patient-reported toxic effects, including symptom frequency, severity, and interference with daily activities (score range, 0 [none] to 4 [very severe]), and practitioner-measured toxic effects, including swallowing, oral pain, and hoarseness (score range, 1 [mild] to 5 [death]). Of the 44 patients included in the analysis (39 men, 5 women; mean [SD] age, 61 [8.4] years), there were 327 analyzable pairs of CTCAE and PRO-CTCAE symptom surveys and no treatment delays due to toxic effects. Patient-reported and practitioner-reported symptom severity agreement was high at baseline when most symptoms were absent but declined throughout treatment as toxic effects increased. Most disagreement was due to lower severity of toxic effects reported by practitioners (eg, from 45% agreement at baseline to 27% at the final week of treatment for pain). This was particularly noted for domains that are not easily evaluated by physical examination, such as anxiety and fatigue (eg, severity of fatigue decreased from 43% at baseline to 12% in the final week of treatment). Practitioner-reported toxic effects are lower than patient self-reports during head and neck chemoradiotherapy. The inclusion of patient-reported symptomatic toxic effects provides information that can potentially enhance clinical management and improve data quality in clinical trials

    Genetic Regulation of Platelet Receptor Expression and Function: Application in Clinical Practice and Drug Development

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    Understanding genetic contributions to platelet function could have profound clinical ramifications for personalizing platelet-directed pharmacotherapy, by providing insight into the risks and possible benefits associated with specific genotypes. This article represents an integrated summary of presentations related to genetic regulation of platelet receptor expression and function given at the Fifth Annual Platelet Colloquium in January 2010. It is supplemented with additional highlights from the literature covering 1) approaches to determining and evidence for the associations of genetic variants with platelet hypo- and hyperresponsive phenotypes, 2) the ramifications of these polymorphisms with regard to clinical responses to antiplatelet therapies, and 3) the role of platelet function/genetic testing in guiding antiplatelet therapy

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Geography and ecology shape the phylogenetic composition of Amazonian tree communities

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    AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
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