849 research outputs found

    FRA2A is a CGG repeat expansion associated with silencing of AFF3

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    Folate-sensitive fragile sites (FSFS) are a rare cytogenetically visible subset of dynamic mutations. Of the eight molecularly characterized FSFS, four are associated with intellectual disability (ID). Cytogenetic expression results from CGG tri-nucleotide-repeat expansion mutation associated with local CpG hypermethylation and transcriptional silencing. The best studied is the FRAXA site in the FMR1 gene, where large expansions cause fragile X syndrome, the most common inherited ID syndrome. Here we studied three families with FRA2A expression at 2q11 associated with a wide spectrum of neurodevelopmental phenotypes. We identified a polymorphic CGG repeat in a conserved, brain-active alternative promoter of the AFF3 gene, an autosomal homolog of the X-linked AFF2/FMR2 gene: Expansion of the AFF2 CGG repeat causes FRAXE ID. We found that FRA2A-expressing individuals have mosaic expansions of the AFF3 CGG repeat in the range of several hundred repeat units. Moreover, bisulfite sequencing and pyrosequencing both suggest AFF3 promoter hypermethylation. cSNP-analysis demonstrates monoallelic expression of the AFF3 gene in FRA2A carriers thus predicting that FRA2A expression results in functional haploinsufficiency for AFF3 at least in a subset of tissues. By whole-mount in situ hybridization the mouse AFF3 ortholog shows strong regional expression in the developing brain, somites and limb buds in 9.5-12.5dpc mouse embryos. Our data suggest that there may be an association between FRA2A and a delay in the acquisition of motor and language skills in the families studied here. However, additional cases are required to firmly establish a causal relationship

    A Systematic Review of Mosquito Coils and Passive Emanators: Defining Recommendations for Spatial Repellency Testing Methodologies.

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    Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control

    1α,25(OH)2-3-Epi-Vitamin D3, a Natural Physiological Metabolite of Vitamin D3: Its Synthesis, Biological Activity and Crystal Structure with Its Receptor

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    Background: The 1 alpha,25-dihydroxy-3-epi-vitamin-D(3) (1 alpha,25(OH)(2)-3-epi-D(3)), a natural metabolite of the seco-steroid vitamin D(3), exerts its biological activity through binding to its cognate vitamin D nuclear receptor (VDR), a ligand dependent transcription regulator. In vivo action of 1 alpha,25(OH)(2)-3-epi-D(3) is tissue-specific and exhibits lowest calcemic effect compared to that induced by 1 alpha,25(OH)(2)D(3). To further unveil the structural mechanism and structure-activity relationships of 1 alpha,25(OH)(2)-3-epi-D3 and its receptor complex, we characterized some of its in vitro biological properties and solved its crystal structure complexed with human VDR ligand-binding domain (LBD). Methodology/Principal Findings: In the present study, we report the more effective synthesis with fewer steps that provides higher yield of the 3-epimer of the 1 alpha,25(OH)(2)D(3). We solved the crystal structure of its complex with the human VDR-LBD and found that this natural metabolite displays specific adaptation of the ligand-binding pocket, as the 3-epimer maintains the number of hydrogen bonds by an alternative water-mediated interaction to compensate the abolished interaction with Ser278. In addition, the biological activity of the 1 alpha,25(OH)(2)-3-epi-D(3) in primary human keratinocytes and biochemical properties are comparable to 1 alpha,25(OH)(2)D(3). Conclusions/Significance: The physiological role of this pathway as the specific biological action of the 3-epimer remains unclear. However, its high metabolic stability together with its significant biologic activity makes this natural metabolite an interesting ligand for clinical applications. Our new findings contribute to a better understanding at molecular level how natural metabolites of 1 alpha,25(OH)(2)D(3) lead to significant activity in biological systems and we conclude that the C3-epimerization pathway produces an active metabolite with similar biochemical and biological properties to those of the 1 alpha,25(OH)(2)D(3)

    Analysis of Mice Lacking DNaseI Hypersensitive Sites at the 5′ End of the IgH Locus

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    The 5′ end of the IgH locus contains a cluster of DNaseI hypersensitive sites, one of which (HS1) was shown to be pro-B cell specific and to contain binding sites for the transcription factors PU.1, E2A, and Pax5. These data as well as the location of the hypersensitive sites at the 5′ border of the IgH locus suggested a possible regulatory function for these elements with respect to the IgH locus. To test this notion, we generated mice carrying targeted deletions of either the pro-B cell specific site HS1 or the whole cluster of DNaseI hypersensitive sites. Lymphocytes carrying these deletions appear to undergo normal development, and mutant B cells do not exhibit any obvious defects in V(D)J recombination, allelic exclusion, or class switch recombination. We conclude that deletion of these DNaseI hypersensitive sites does not have an obvious impact on the IgH locus or B cell development

    Cigarette smoking and reasons for leaving school among school dropouts in South Africa

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    School dropouts are at heightened risk of tobacco use compared to in-school learners. School dropouts are described as those not currently enrolled in school for the academic year, have not completed their schooling, and are between 13 and 20 years old. This paper examines the relationship between reasons for leaving school and past month cigarette smoking, taking into account gender differences.Multiple logistic regression was used to analyse survey data (n = 4185). Geographical location was also incorporated into the analysis as effect moderators

    Tertiary osteochondral defect of the talus treated by a novel contoured metal implant

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    The primary treatment of most osteochondral defects of the talus is arthroscopic debridement and bone marrow stimulation. There is no optimal treatment for large lesions or for those in which primary treatment has failed. We report a 20-year-old female patient with persistent symptoms after two previous arthroscopic procedures. Computed tomography showed a cystic defect of the medial talar dome, sized 17 × 8 × 8 mm. The patient was treated with a novel contoured metal implant. At 1 and 2 years after surgery, the patient reported considerable reduction in pain and had resumed playing korfball at competitive level

    Seasonal and Altitudinal Changes in Population Density of 20 Species of Drosophila in Chamundi Hill

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    A year long study was conducted to analyze the altitudinal and seasonal variation in a population of Drosophila (Diptera: Drosophilidae) on Chamundi hill of Mysore, Karnataka State, India. A total of 16,671 Drosophila flies belonging to 20 species of 4 subgenera were collected at altitudes of 680 m, 780 m, 880 m and 980 m. The subgenus Sophophora was predominant with 14 species and the subgenus Drosilopha was least represented with only a single species. Cluster analysis and constancy methods were used to analyze the species occurrence qualitatively. Altitudinal changes in the population density, and relative abundance of the different species at different seasons were also studied. The diversity of the Drosophila community was assessed by applying the Simpson and Berger-Parker indices. At 680 m the Simpson Index was low at 0.129 and the Berger- Parker index was high at 1.1 at 980 m. Linear regression showed that the Drosophila community was positively correlated with rainfall but not elevation, Furthermore the density of Drosophila changed significantly in different seasons (F = 11.20, df 2, 9; P<0.004). The distributional pattern of a species or related group of species was uneven in space and time. D. malerkotliana and D. nasuta were found at all altitudes and can be considered as dominant species

    Continued improvement of cardiovascular mortality in Hungary - impact of increased cardio-metabolic prescriptions

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    <p>Abstract</p> <p>Background</p> <p>During the last 35 years the poor ranking of Hungary on the list of life expectancy at birth among European countries, has not changed. In 1970 our lag behind the leading European countries was the smallest. The gap was growing between 1970 and 1993 but from 1994 onwards the life expectancy at birth in Hungary has increased continuously and somewhat faster than in other European countries. The aim of this study was to analyze the association between decreasing cardiovascular mortality rates, as a main cause of death and the increase in cardio-metabolic prescriptions and possible changes in lifestyle behavior.</p> <p>Methods</p> <p>Analyses were conducted on national data concerning cardiovascular mortality and the number of cardio-metabolic drug prescription per capita. The association between yearly rates of cardiovascular events and changes in antihypertensive, antilipidemic and antidiabetic prescription rates was analyzed. The changes in other cardiovascular risk factors, like lifestyle were also considered.</p> <p>Results</p> <p>We observed a remarkable decline of mortality due to stroke and acute myocardial infarction (AMI). The fall was significantly associated with all prescription rates. The proportion of each treatment type responsible for suppression of specific mortality rates is different. All treatment types comparably improved stroke mortality, while antilipidemic therapy improved AMI outcome.</p> <p>Conclusions</p> <p>These results emphasize the importance of a comprehensive strategy that maximizes the population coverage of effective treatments. Hungary appears to be at the beginning of the fourth stage of epidemiologic transition, i.e. it has entered the stage of delayed chronic noninfectious diseases.</p

    Computer-Based Screening of Functional Conformers of Proteins

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    A long-standing goal in biology is to establish the link between function, structure, and dynamics of proteins. Considering that protein function at the molecular level is understood by the ability of proteins to bind to other molecules, the limited structural data of proteins in association with other bio-molecules represents a major hurdle to understanding protein function at the structural level. Recent reports show that protein function can be linked to protein structure and dynamics through network centrality analysis, suggesting that the structures of proteins bound to natural ligands may be inferred computationally. In the present work, a new method is described to discriminate protein conformations relevant to the specific recognition of a ligand. The method relies on a scoring system that matches critical residues with central residues in different structures of a given protein. Central residues are the most traversed residues with the same frequency in networks derived from protein structures. We tested our method in a set of 24 different proteins and more than 260,000 structures of these in the absence of a ligand or bound to it. To illustrate the usefulness of our method in the study of the structure/dynamics/function relationship of proteins, we analyzed mutants of the yeast TATA-binding protein with impaired DNA binding. Our results indicate that critical residues for an interaction are preferentially found as central residues of protein structures in complex with a ligand. Thus, our scoring system effectively distinguishes protein conformations relevant to the function of interest

    Cell Invasion by Neisseria meningitidis Requires a Functional Interplay between the Focal Adhesion Kinase, Src and Cortactin

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    Entry of Neisseria meningitidis (the meningococcus) into human brain microvascular endothelial cells (HBMEC) is mediated by fibronectin or vitronectin bound to the surface protein Opc forming a bridge to the respective integrins. This interaction leads to cytoskeletal rearrangement and uptake of meningococci. In this study, we determined that the focal adhesion kinase (FAK), which directly associates with integrins, is involved in integrin-mediated internalization of N. meningitidis in HBMEC. Inhibition of FAK activity by the specific FAK inhibitor PF 573882 reduced Opc-mediated invasion of HBMEC more than 90%. Moreover, overexpression of FAK mutants that were either impaired in the kinase activity or were not capable of autophosphorylation or overexpression of the dominant-negative version of FAK (FRNK) blocked integrin-mediated internalization of N. meningitidis. Importantly, FAK-deficient fibroblasts were significantly less invaded by N. meningitidis. Furthermore, N. meningitidis induced tyrosine phosphorylation of several host proteins including the FAK/Src complex substrate cortactin. Inhibition of cortactin expression by siRNA silencing and mutation of critical amino acid residues within cortactin, that encompass Arp2/3 association and dynamin binding, significantly reduced meningococcal invasion into eukaryotic cells suggesting that both domains are critical for efficient uptake of N. meningitidis into eukaryotic cells. Together, these results indicate that N. meningitidis exploits the integrin signal pathway for its entry and that FAK mediates the transfer of signals from activated integrins to the cytoskeleton. A cooperative interplay between FAK, Src and cortactin then enables endocytosis of N. meningitidis into host cells
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