68 research outputs found

    Novel cell death program leads to neutrophil extracellular traps

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    Neutrophil extracellular traps (NETs) are extracellular structures composed of chromatin and granule proteins that bind and kill microorganisms. We show that upon stimulation, the nuclei of neutrophils lose their shape, and the eu- and heterochromatin homogenize. Later, the nuclear envelope and the granule membranes disintegrate, allowing the mixing of NET components. Finally, the NETs are released as the cell membrane breaks. This cell death process is distinct from apoptosis and necrosis and depends on the generation of reactive oxygen species (ROS) by NADPH oxidase. Patients with chronic granulomatous disease carry mutations in NADPH oxidase and cannot activate this cell-death pathway or make NETs. This novel ROS-dependent death allows neutrophils to fulfill their antimicrobial function, even beyond their lifespan

    B-type defects in Landau-Ginzburg models

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    We consider Landau-Ginzburg models with possibly different superpotentials glued together along one-dimensional defect lines. Defects preserving B-type supersymmetry can be represented by matrix factorisations of the difference of the superpotentials. The composition of these defects and their action on B-type boundary conditions is described in this framework. The cases of Landau-Ginzburg models with superpotential W=X^d and W=X^d+Z^2 are analysed in detail, and the results are compared to the CFT treatment of defects in N=2 superconformal minimal models to which these Landau-Ginzburg models flow in the IR.Comment: 50 pages, 2 figure

    Deficiency of caspase recruitment domain family, member 11 (CARD11), causes profound combined immunodeficiency in human subjects.

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    BACKGROUND: Profound combined immunodeficiency can present with normal numbers of T and B cells, and therefore the functional defect of the cellular and humoral immune response is often not recognized until the first severe clinical manifestation. Here we report a patient of consanguineous descent presenting at 13 months of age with hypogammaglobulinemia, Pneumocystis jirovecii pneumonia, and a suggestive family history. OBJECTIVE: We sought to identify the genetic alteration in a patient with combined immunodeficiency and characterize human caspase recruitment domain family, member 11 (CARD11), deficiency. METHODS: Molecular, immunologic, and functional assays were performed. RESULTS: The immunologic characterization revealed only subtle changes in the T-cell and natural killer cell compartment, whereas B-cell differentiation, although normal in number, was distinctively blocked at the transitional stage. Genetic evaluation revealed a homozygous deletion of exon 21 in CARD11 as the underlying defect. This deletion abrogated protein expression and activation of the canonical nuclear factor κB (NF-κB) pathway in lymphocytes after antigen receptor or phorbol 12-myristate 13-acetate stimulation, whereas CD40 signaling in B cells was preserved. The abrogated activation of the canonical NF-κB pathway was associated with severely impaired upregulation of inducible T-cell costimulator, OX40, cytokine production, proliferation of T cells, and B cell-activating factor receptor expression on B cells. CONCLUSION: Thus in patients with CARD11 deficiency, the combination of impaired activation and especially upregulation of inducible T-cell costimulator on T cells, together with severely disturbed peripheral B-cell differentiation, apparently leads to a defective T-cell/B-cell cooperation and probably germinal center formation and clinically results in severe immunodeficiency. This report discloses the crucial and nonredundant role of canonical NF-κB activation and specifically CARD11 in the antigen-specific immune response in human subjects

    Broad AOX expression in a genetically tractable mouse model does not disturb normal physiology

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    Plants and many lower organisms, but not mammals, express alternative oxidases (AOXs) that branch the mitochondrial respiratory chain, transferring electrons directly from ubiquinol to oxygen without proton pumping. Thus, they maintain electron flow under conditions when the classical respiratory chain is impaired, limiting excess production of oxygen radicals and supporting redox and metabolic homeostasis. AOX from Ciona intestinalis has been used to study and mitigate mitochondrial impairments in mammalian cell lines, Drosophila disease models and, most recently, in the mouse, where multiple lentivector-AOX transgenes conferred substantial expression in specific tissues. Here, we describe a genetically tractable mouse model in which Ciona AOX has been targeted to the Rosa26 locus for ubiquitous expression. The AOX(Rosa26) mouse exhibited only subtle phenotypic effects on respiratory complex formation, oxygen consumption or the global metabolome, and showed an essentially normal physiology. AOX conferred robust resistance to inhibitors of the respiratory chain in organello; moreover, animals exposed to a systemically applied LD50 dose of cyanide did not succumb. The AOX(Rosa26) mouse is a useful tool to investigate respiratory control mechanisms and to decipher mitochondrial disease aetiology in vivo.Peer reviewe

    Effective Immunological Guidance of Genetic Analyses Including Exome Sequencing in Patients Evaluated for Hemophagocytic Lymphohistiocytosis

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    We report our experience in using flow cytometry-based immunological screening prospectively as a decision tool for the use of genetic studies in the diagnostic approach to patients with hemophagocytic lymphohistiocytosis (HLH). We restricted genetic analysis largely to patients with abnormal immunological screening, but included whole exome sequencing (WES) for those with normal findings upon Sanger sequencing. Among 290 children with suspected HLH analyzed between 2010 and 2014 (including 17 affected, but asymptomatic siblings), 87/162 patients with "full" HLH and 79/111 patients with "incomplete/atypical" HLH had normal immunological screening results. In 10 patients, degranulation could not be tested. Among the 166 patients with normal screening, genetic analysis was not performed in 107 (all with uneventful follow-up), while 154 single gene tests by Sanger sequencing in the remaining 59 patients only identified a single atypical CHS patient. Flow cytometry correctly predicted all 29 patients with FHL-2, XLP1 or 2. Among 85 patients with defective NK degranulation (including 13 asymptomatic siblings), 70 were Sanger sequenced resulting in a genetic diagnosis in 55 (79%). Eight patients underwent WES, revealing mutations in two known and one unknown cytotoxicity genes and one metabolic disease. FHL3 was the most frequent genetic diagnosis. Immunological screening provided an excellent decision tool for the need and depth of genetic analysis of HLH patients and provided functionally relevant information for rapid patient classification, contributing to a significant reduction in the time from diagnosis to transplantation in recent years

    Defects and Bulk Perturbations of Boundary Landau-Ginzburg Orbifolds

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    We propose defect lines as a useful tool to study bulk perturbations of conformal field theories, in particular to analyse the induced renormalisation group flows of boundary conditions. As a concrete example we investigate bulk perturbations of N=2 supersymmetric minimal models. To these perturbations we associate a special class of defects between the respective UV and IR theories, whose fusion with boundary conditions indeed reproduces the behaviour of the latter under the corresponding RG flows. v2: Some explanations added in section 4, minor changes.Comment: 37 pages, 6 figure

    Effect of Virulence Factors on the Photodynamic Inactivation of Cryptococcus neoformans

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    Opportunistic fungal pathogens may cause an array of superficial infections or serious invasive infections, especially in immunocompromised patients. Cryptococcus neoformans is a pathogen causing cryptococcosis in HIV/AIDS patients, but treatment is limited due to the relative lack of potent antifungal agents. Photodynamic inactivation (PDI) uses the combination of non-toxic dyes called photosensitizers and harmless visible light, which produces singlet oxygen and other reactive oxygen species that produce cell inactivation and death. We report the use of five structurally unrelated photosensitizers (methylene blue, Rose Bengal, selenium derivative of a Nile blue dye, a cationic fullerene and a conjugate between poly-L-lysine and chlorin(e6)) combined with appropriate wavelengths of light to inactivate C. neoformans. Mutants lacking capsule and laccase, and culture conditions that favoured melanin production were used to probe the mechanisms of PDI and the effect of virulence factors. The presence of cell wall, laccase and melanin tended to protect against PDI, but the choice of the appropriate photosensitizers and dosimetry was able to overcome this resistance.Fundação de Amparo à Pesquisa do Estado de São Paulo (2010/13313–9

    Medical assessments and measurements in ELSA-Brasil

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    Este artigo descreve os exames clínicos realizados no Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Alguns deles (antropometria, pressão arterial e índice tornozelo-braquial) já têm uso clínico consolidado. Outros, como a velocidade de onda de pulso, variabilidade da frequência cardíaca e medida da espessura médio-intimal de carótidas, carecem de valor de referência na população brasileira não doente e podem constituir preditores importantes de desfechos cardiovasculares. A medida da pressão arterial após manobra postural foi incluída no ELSA-Brasil porque foi pouco testada em estudos epidemiológicos. O ELSA-Brasil inovou na realização do índice tornozelo-braquial, ao usar um aparelho automático em substituição à coluna de mercúrio na medida da pressão arterial, e também na medida do diâmetro ântero-posterior do lobo direito do fígado pela ultrassonografia, proposta para avaliação quantitativa da doença hepática gordurosa não-alcoólica. Os participantes são indivíduos mais jovens (a partir dos 35 anos) do que em outras coortes focadas no estudo da aterosclerose subclínica. A inclusão de indivíduos mais jovens e a diversidade dos exames realizados tornam o ELSA-Brasil um estudo relevante no contexto da epidemiologia brasileira e internacional.The article describes assessments and measurements performed in the Brazilian Longitudinal Study for Adult Health (ELSA-Brasil). Some assessments including anthropometric assessment, casual blood pressure measurement, and ankle-brachial index have an established clinical application while others including pulse wave velocity, heart rate variability, and carotid intima-media thickness have no established application and do not have reference values for healthy Brazilian population but may be important predictors of cardiovascular outcomes. Blood pressure measurement following postural change maneuver was included in the ELSA-Brasil because it has not been much tested in epidemiological studies. Innovative approaches were developed for assessing the ankle-brachial index using an automatic device instead of the mercury column to measure blood pressure and for assessing the anterior-posterior diameter of the right lobe of the liver by ultrasound for quantitative assessment of nonalcoholic fatty liver disease. All ELSA-Brasil subjects were younger (35 years or more) than those included in other cohorts studying subclinical atherosclerosis. The inclusion of younger individuals and a variety of assessments make the ELSA-Brasil a relevant epidemiology study nationwide and worldwide

    A chromosome conformation capture ordered sequence of the barley genome

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