320 research outputs found

    The Diatom Flora of Phosphorus-Enriched And Unenriched Sites in an Everglades Marsh

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    Diatoms are used as environmental indicators in the Florida Everglades, a large subtropical wetland highly impacted by phosphorus pollution. However, the taxonomy of the diatom flora, a mix of temperate and tropical diatoms, is understudied. Therefore, we analyzed the taxonomy of 71 diatom taxa collected in Water Conservation Area 2A (WCA-2A). Diatoms were analyzed from sediment cores and from floating algal mats collected in phosphorus-enriched northern WCA-2A and in relatively unenriched southern WCA-2A. In addition, diatoms were analyzed from experimental mesocosms in southern WCA- 2A dosed with 0-126 µgL-1 P-PO4. Total phosphorus optima were calculated for dominant taxa. Average percent abundances in phosphorus-enriched and unenriched conditions are given for all taxa. Eleven taxa were dominant (\u3e5% abundance in at least one sample) in unenriched conditions, 17 taxa were observed only in phosphorus-enriched conditions, and 9 taxa were observed only below 2 cm in sediment cores. We compared the flora to taxonomical accounts of diatoms from temperate and tropical regions, with a special focus on nearby Antillean islands (Cuba, Jamaica, and Puerto Rico). Light microscope images of each taxon and SEM images of selected taxa are presented. Taxonomical measurements are given for each taxon, and differences from descriptions in other taxonomical accounts are discussed. A new combination, Achnanthes caledonica Lange-Bertalot = Achnanthidium caledonicum (Lange-Bertalot) comb nov. is proposed

    Made-to-measure malaria vector control strategies: rational design based on insecticide properties and coverage of blood resources for mosquitoes.

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    Eliminating malaria from highly endemic settings will require unprecedented levels of vector control. To suppress mosquito populations, vector control products targeting their blood hosts must attain high biological coverage of all available sources, rather than merely high demographic coverage of a targeted resource subset, such as humans while asleep indoors. Beyond defining biological coverage in a measurable way, the proportion of blood meals obtained from humans and the proportion of bites upon unprotected humans occurring indoors also suggest optimal target product profiles for delivering insecticides to humans or livestock. For vectors that feed only occasionally upon humans, preferred animal hosts may be optimal targets for mosquito-toxic insecticides, and vapour-phase insecticides optimized to maximize repellency, rather than toxicity, may be ideal for directly protecting people against indoor and outdoor exposure. However, for vectors that primarily feed upon people, repellent vapour-phase insecticides may be inferior to toxic ones and may undermine the impact of contact insecticides applied to human sleeping spaces, houses or clothing if combined in the same time and place. These concepts are also applicable to other mosquito-borne anthroponoses so that diverse target species could be simultaneously controlled with integrated vector management programmes. Measurements of these two crucial mosquito behavioural parameters should now be integrated into programmatically funded, longitudinal, national-scale entomological monitoring systems to inform selection of available technologies and investment in developing new ones

    Detection of a dna methylation signature for the intellectual developmental disorder, x-linked, syndromic, armfield type

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    A growing number of genetic neurodevelopmental disorders are known to be associated with unique genomic DNA methylation patterns, called episignatures, which are detectable in peripheral blood. The intellectual developmental disorder, X-linked, syndromic, Armfield type (MRXSA) is caused by missense variants in FAM50A. Functional studies revealed the pathogenesis to be a spliceosomopathy that is characterized by atypical mRNA processing during development. In this study, we assessed the peripheral blood specimens in a cohort of individuals with MRXSA and detected a unique and highly specific DNA methylation episignature associated with this disorder. We used this episignature to construct a support vector machine model capable of sensitive and specific identification of individuals with pathogenic variants in FAM50A. This study contributes to the expanding number of genetic neurodevelopmental disorders with defined DNA methylation episignatures, provides an additional understanding of the associated molecular mechanisms, and further enhances our ability to diagnose patients with rare disorders

    Evidence gap map of performance measurement and management in primary care delivery systems in low- and middle-income countries – Study protocol [version 1; referees: 2 approved]

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    Background. For the last two decades there has been growing interest in governmental and global health stakeholders about the role that performance measurement and management systems can play for the production of high-quality and safely delivered primary care services. Despite recognition and interest, the gaps in evidence in this field of research and practice in low- and middle-income countries remain poorly characterized. This study will develop an evidence gap map in the area of performance management in primary care delivery systems in low- and middle-income countries. Methods. The evidence gap map will follow the methodology developed by 3Ie, the International Initiative for Impact Evaluation, to systematically map evidence and research gaps. The process starts with the development of the scope by creating an evidence-informed framework that helps identify the interventions and outcomes of relevance as well as help define inclusion and exclusion criteria. A search strategy is then developed to guide the systematic search of the literature, covering the following databases: Medline (Ovid), Embase (Ovid), CAB Global Health (Ovid), CINAHL (Ebsco), Cochrane Library, Scopus (Elsevier), and Econlit (Ovid). Sources of grey literature are also searched. Studies that meet the inclusion criteria are systematically coded, extracting data on intervention, outcome, measures, context, geography, equity, and study design. Systematic reviews are also critically appraised using an existing standard checklist. Impact evaluations are not appraised but will be coded according to study design. The process of map-building ends with the creation of an evidence gap map graphic that displays the available evidence according to the intervention and outcome framework of interest. Discussion. Applications arising from the evidence map will be discussed in a separate paper that will summarize findings and make recommendations for the development of a prioritized research agenda

    Results of a phase I-II study of fenretinide and rituximab for patients with indolent B-cell lymphoma and mantle cell lymphoma.

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    Fenretinide, a synthetic retinoid, induces apoptotic cell death in B-cell non-Hodgkin lymphoma (B-NHL) and acts synergistically with rituximab in preclinical models. We report results from a phase I-II study of fenretinide with rituximab for B-NHLs. Eligible diagnoses included indolent B-NHL or mantle cell lymphoma. The phase I design de-escalated from fenretinide at 900 mg/

    Enough is not enough: Medical students’ knowledge of early warning signs of childhood cancer

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    Background. The reported incidence of childhood cancer in upper-middle-income South Africa (SA) is much lower than in high-income countries, partly due to under-diagnosis and under-reporting. Documented survival rates are disturbingly low, prompting an analysis of potential factors that may be responsible.Objectives. To determine final-year medical students’ level of knowledge of early warning signs of childhood cancer and whether a correlation existed between test scores and participants’ age, gender and previous exposure to a person with cancer.Methods. A two-part questionnaire based on the Saint Siluan mnemonic, testing both recall and recognition of early warning signs of childhood cancer, was administered. The Mann-Whitney-Wilcoxon test was used to assess differences in continuous and count variables between demographic data, experience and responses, and Fisher’s exact test and Spearman’s rank correlation coefficient were used to determine correlations between demographic data, previous contact with persons with cancer and test scores. A novel equality ratio was calculated to compare the recall and recognition sections and allowed analysis of recall v. recognition.Results. The 84 participants recalled a median of six signs each (interquartile range 4 - 7) and correctly recognised a median of 70% in the recognition section, considered a pass mark. There was no correlation between participants’ age, gender, previous contact with a person with cancer and recognition scores. Students with previous exposure to a person with cancer had higher scores in the recall section, but this did not achieve statistical significance. Students were able to recognise more signs of haematological malignancies than central nervous system (CNS) malignancies.Conclusion. The study demonstrated a marked inconsistency between recall and recognition of signs of childhood cancer, with signs of CNS malignancies being least recognised. However, the majority of students could recognise enough early warning signs to meet the university pass standard. Although this study demonstrated acceptable recognition of early warning signs of childhood cancer at one university, we suggest that long-term recall in medical practitioners is poor, as reflected in the low age-standardised ratios of childhood cancer in SA. We recommend increased ongoing exposure to paediatric oncology in medical school and improved awareness programmes to increase early referrals.

    Clinical epigenomics: genome-wide DNA methylation analysis for the diagnosis of Mendelian disorders

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    Purpose: We describe the clinical implementation of genome-wide DNA methylation analysis in rare disorders across the EpiSign diagnostic laboratory network and the assessment of results and clinical impact in the first subjects tested. Methods: We outline the logistics and data flow between an integrated network of clinical diagnostics laboratories in Europe, the United States, and Canada. We describe the clinical validation of EpiSign using 211 specimens and assess the test performance and diagnostic yield in the first 207 subjects tested involving two patient subgroups: the targeted cohort (subjects with previous ambiguous/inconclusive genetic findings including genetic variants of unknown clinical significance) and the screening cohort (subjects with clinical findings consistent with hereditary neurodevelopmental syndromes and no previous conclusive genetic findings). Results: Among the 207 subjects tested, 57 (27.6%) were positive for a diagnostic episignature including 48/136 (35.3%) in the targeted cohort and 8/71 (11.3%) in the screening cohort, with 4/207 (1.9%) remaining inconclusive after EpiSign analysis. Conclusion: This study describes the implementation of diagnostic clinical genomic DNA methylation testing in patients with rare disorders. It provides strong evidence of clinical utility of EpiSign analysis, including the ability to provide conclusive findings in the majority of subjects tested

    The challenges of communicating research evidence in practice: perspectives from UK health visitors and practice nurses

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    <p>Background: Health practitioners play a pivotal role in providing patients with up-to-date evidence and health information. Evidence-based practice and patient-centred care are transforming the delivery of healthcare in the UK. Health practitioners are increasingly balancing the need to provide evidence-based information against that of facilitating patient choice, which may not always concur with the evidence base. There is limited research exploring how health practitioners working in the UK, and particularly those more autonomous practitioners such as health visitors and practice nurses working in community practice settings, negotiate this challenge. This research provides a descriptive account of how health visitors and practice nurses negotiate the challenges of communicating health information and research evidence in practice.</p> <p>Methods: A total of eighteen in-depth telephone interviews were conducted in the UK between September 2008 and May 2009. The participants comprised nine health visitors and nine practice nurses, recruited via adverts on a nursing website, posters at a practitioner conference and through recommendation. Thematic analysis, with a focus on constant comparative method, was used to analyse the data.</p> <p>Results: The data were grouped into three main themes: communicating evidence to the critically-minded patient; confidence in communicating evidence; and maintaining the integrity of the patient-practitioner relationship. These findings highlight some of the daily challenges that health visitors and practice nurses face with regard to the complex and dynamic nature of evidence and the changing attitudes and expectations of patients. The findings also highlight the tensions that exist between differing philosophies of evidence-based practice and patient-centred care, which can make communicating about evidence a daunting task.</p> <p>Conclusions: If health practitioners are to be effective at communicating research evidence, we suggest that more research and resources need to be focused on contextual factors, such as how research evidence is negotiated, appraised and communicated within the dynamic patient-practitioner relationship.</p&gt
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