117 research outputs found

    Relationship between haemagglutination-inhibiting antibody titres and clinical protection against influenza: development and application of a bayesian random-effects model

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    <p>Abstract</p> <p>Background</p> <p>Antibodies directed against haemagglutinin, measured by the haemagglutination inhibition (HI) assay are essential to protective immunity against influenza infection. An HI titre of 1:40 is generally accepted to correspond to a 50% reduction in the risk of contracting influenza in a susceptible population, but limited attempts have been made to further quantify the association between HI titre and protective efficacy.</p> <p>Methods</p> <p>We present a model, using a meta-analytical approach, that estimates the level of clinical protection against influenza at any HI titre level. Source data were derived from a systematic literature review that identified 15 studies, representing a total of 5899 adult subjects and 1304 influenza cases with interval-censored information on HI titre. The parameters of the relationship between HI titre and clinical protection were estimated using Bayesian inference with a consideration of random effects and censorship in the available information.</p> <p>Results</p> <p>A significant and positive relationship between HI titre and clinical protection against influenza was observed in all tested models. This relationship was found to be similar irrespective of the type of viral strain (A or B) and the vaccination status of the individuals.</p> <p>Conclusion</p> <p>Although limitations in the data used should not be overlooked, the relationship derived in this analysis provides a means to predict the efficacy of inactivated influenza vaccines when only immunogenicity data are available. This relationship can also be useful for comparing the efficacy of different influenza vaccines based on their immunological profile.</p

    Calcium modulates force sensing by the von Willebrand factor A2 domain

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    von Willebrand factor (VWF) multimers mediate primary adhesion and aggregation of platelets. VWF potency critically depends on multimer size, which is regulated by a feedback mechanism involving shear-induced unfolding of the VWF-A2 domain and cleavage by the metalloprotease ADAMTS-13. Here we report crystallographic and single-molecule optical tweezers data on VWF-A2 providing mechanistic insight into calcium-mediated stabilization of the native conformation that protects A2 from cleavage by ADAMTS-13. Unfolding of A2 requires higher forces when calcium is present and primarily proceeds through a mechanically stable intermediate with non-native calcium coordination. Calcium further accelerates refolding markedly, in particular, under applied load. We propose that calcium improves force sensing by allowing reversible force switching under physiologically relevant hydrodynamic conditions. Our data show for the first time the relevance of metal coordination for mechanical properties of a protein involved in mechanosensing

    The European Hematology Association Roadmap for European Hematology Research. A Consensus Document

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    Abstract The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at Euro 23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine sections in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients. Received December 15, 2015. Accepted January 27, 2016. Copyright © 2016, Ferrata Storti Foundatio

    The European Hematology Association Roadmap for European Hematology Research: a consensus document

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    The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at €23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine ‘sections’ in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients

    A high-throughput sequencing test for diagnosing inherited bleeding, thrombotic, and platelet disorders.

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    Inherited bleeding, thrombotic, and platelet disorders (BPDs) are diseases that affect ∼300 individuals per million births. With the exception of hemophilia and von Willebrand disease patients, a molecular analysis for patients with a BPD is often unavailable. Many specialized tests are usually required to reach a putative diagnosis and they are typically performed in a step-wise manner to control costs. This approach causes delays and a conclusive molecular diagnosis is often never reached, which can compromise treatment and impede rapid identification of affected relatives. To address this unmet diagnostic need, we designed a high-throughput sequencing platform targeting 63 genes relevant for BPDs. The platform can call single nucleotide variants, short insertions/deletions, and large copy number variants (though not inversions) which are subjected to automated filtering for diagnostic prioritization, resulting in an average of 5.34 candidate variants per individual. We sequenced 159 and 137 samples, respectively, from cases with and without previously known causal variants. Among the latter group, 61 cases had clinical and laboratory phenotypes indicative of a particular molecular etiology, whereas the remainder had an a priori highly uncertain etiology. All previously detected variants were recapitulated and, when the etiology was suspected but unknown or uncertain, a molecular diagnosis was reached in 56 of 61 and only 8 of 76 cases, respectively. The latter category highlights the need for further research into novel causes of BPDs. The ThromboGenomics platform thus provides an affordable DNA-based test to diagnose patients suspected of having a known inherited BPD.This study, including the enrollment of cases, sequencing, and analysis received support from the National Institute for Health Research (NIHR) BioResource–Rare Diseases. The NIHR BioResource is funded by the NIHR (http://www.nihr.ac.uk). Research in the Ouwehand Laboratory is also supported by grants from Bristol-Myers Squibb, the British Heart Foundation, the British Society of Haematology, the European Commission, the MRC, the NIHR, and the Wellcome Trust; the laboratory also receives funding from National Health Service Blood and Transplant (NHSBT). The clinical fellows received funding from the MRC (C.L. and S.K.W.); the NIHR–Rare Diseases Translational Research Collaboration (S. Sivapalaratnam); and the British Society for Haematology and National Health Service Blood and Transplant (T.K.B.).This is the author accepted manuscript. The final version is available from American Society of Hematology via http://dx.doi.org/10.1182/blood-2015-12-688267

    バレイショ近縁種における種の分化 XIII. S.acaule X S.demissumより得た7倍雑種の染色体行動と両親ゲノムの類縁関係

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    中央アンデス産Acaulia群4倍種S. acaule (acl, 2n=48)とメキシコ産Demissa群6倍種S. demissum (dms, 2n=72)のゲノムの類縁関係を明らかにするために, 前者を母本として得た7倍雑種(2n=84)の還元分裂における染色体行動と稔性を調べた。以下その結果を要約する。両種間の交雑は極めて困難で, aclを母とした時のみ受粉花数当り0.02の低率で雑種が得られたにすぎない。得られた雑種は, 両親との形態的比較から, aclの非還元性卵とdmsの還元性花粉の受精に起因するものと推定された。この雑種の第1中期における染色体対合行動は甚だしく多様であったが, その対合型のモードは(12)_+(20)_+8_I, その平均対合頻度は(0.18)_V+(1.11)_+(11.73)_+(18.11)_+(7.26)_Iで, 著しく高頻度の3価形成を示す点が特徴的であった。このような対合行動はその後の染色体行動にも反映し, 第1後期では観察細胞のすべてに平均4.8の遅滞染色体がみられ, 第2中期では94%の細胞が分散染色体を示し, 数的平衡核板頻度は0.6%にすぎなかった。稔性は極めて低く, 調査花粉粒数の27%が一見正常であったが, 自殖及び戻交配のいずれにおいても全く種子を生じなかった。上記の観察結果, 特に高頻度で出現した3価染色体の成因を考察して次の知見を得た。すでにaclはAAA^aA^a, dmsはA^dA^dC_1C_1C_2C_2のゲノム型をもつことが知られているので, 当雑種のゲノム型はAAA^aA^aA^dC_1C_2となる。A^dゲノムは若干の構造的差異はもつもののAゲノム群に属することも知られている。したがって, 当雑種にみられる3価形成は, 主に, aclからのAAとdmsからのA^dの3ゲノム間の染色体対合に由来すると推論でき, 両種はこれらのゲノムの相同性によって相互に関係づけられているものと考えられる。 / Meiotic behavior and fertility were studied in a heptaploid F_1 hybrid (2n=84) obtained from crossing S. acaule (acl, 2n=48) with S. demissum (dms, 2n=72), with the aim of assessing a genomic relationship between the parent species. Crossability between the two species was very low, the number of hybrid plants per pollination being only 0.02. Morphological evidence indicated that the hybrid arose through the union of an unreduced egg of acl and a reduced pollen grain of dms. The hybrid had the mean pairing frequency of (0.18)_V+(1.11)_+(11.73)_+(18.11)_+(7.26)_I per cell at metaphase I, with (12)_+(20)_+8_I as the modal configuration. Its subsequent behaviors were extremely irregular, showing several laggards in all the cells and chromatid bridges in occasional cells at anaphase I and also scattered chromosomes in 94% of the cells at metaphase II. The hybrid gave only 27% stainable pollen and no seed either on selfing or on backcrossing with both parents. The pattern of chromosome pairing found in the hybrid was interpreted in terms of genomic relationship between both parent species. From this, it was suggested that one (A) of the two genomes (designated AA^a) which acl possess in its gametes seems to be closely similar to, but not identical with, one (A^d) of the three genomes (A^dC_1C_2) which dms possess in its gemetes

    Abstracts from the 3rd International Genomic Medicine Conference (3rd IGMC 2015)

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