431 research outputs found

    O papel da IL-1β em pacientes com comprometimento periodontal

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    Cytokines, specially the IL-1b type, have been related to the immunopathogenesis of periodontal diseases. Recent researches have reported the mediating role they play in the host defense as well as in the biological activities, which result in the periodontal tissue destruction. This paper aims at reviewing the literature concerned with the interleukin participation in the periodontal disease process.As citocinas, em especial a interleucina-1β, têm sido relacionadas com a imunopatogênese da doença periodontal. Vários estudos relatam o papel de mediadores que estas exercem na defesa do hospedeiro, bem como nas atividades biológicas que culminam com a destruição dos tecidos periodontais. O presente trabalho tem por objetivo fazer uma revisão da literatura a respeito do envolvimento das interleucinas no curso da doença periodontal

    Tissue stiffening coordinates morphogenesis by triggering collective cell migration in vivo.

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    Collective cell migration is essential for morphogenesis, tissue remodelling and cancer invasion. In vivo, groups of cells move in an orchestrated way through tissues. This movement involves mechanical as well as molecular interactions between cells and their environment. While the role of molecular signals in collective cell migration is comparatively well understood, how tissue mechanics influence collective cell migration in vivo remains unknown. Here we investigated the importance of mechanical cues in the collective migration of the Xenopus laevis neural crest cells, an embryonic cell population whose migratory behaviour has been likened to cancer invasion. We found that, during morphogenesis, the head mesoderm underlying the cephalic neural crest stiffens. This stiffening initiates an epithelial-to-mesenchymal transition in neural crest cells and triggers their collective migration. To detect changes in their mechanical environment, neural crest cells use mechanosensation mediated by the integrin-vinculin-talin complex. By performing mechanical and molecular manipulations, we show that mesoderm stiffening is necessary and sufficient to trigger neural crest migration. Finally, we demonstrate that convergent extension of the mesoderm, which starts during gastrulation, leads to increased mesoderm stiffness by increasing the cell density underneath the neural crest. These results show that convergent extension of the mesoderm has a role as a mechanical coordinator of morphogenesis, and reveal a link between two apparently unconnected processes-gastrulation and neural crest migration-via changes in tissue mechanics. Overall, we demonstrate that changes in substrate stiffness can trigger collective cell migration by promoting epithelial-to-mesenchymal transition in vivo. More broadly, our results raise the idea that tissue mechanics combines with molecular effectors to coordinate morphogenesis

    The Nexus of Political Violence and Economic Deprivation: Pakistani Migrants Disrupt the Refugee / Migrant Dichotomy

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    There have been discussions about how the labels “forced migrants,” related to political violence, and “voluntary migrants,” associated with economic factors, cannot be understood in categorical ways. However, there has been less focus on the specificities of the asylum-migrant nexus from the perspective of migrants. This essay discusses how such factors intersect as understood by Pakistani migrants residing in Germany. Through enacting a critical view of Pakistan, the migrants demonstrate how aspects of corruption, economic deprivation, and political violence come to intersect so that is becomes impossible to classify asylum seekers in binary/dichotomous ways

    An integrated whole genome analysis of Mycobacterium tuberculosis reveals insights into relationship between its genome, transcriptome and methylome.

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    Human tuberculosis disease (TB), caused by Mycobacterium tuberculosis (Mtb), is a complex disease, with a spectrum of outcomes. Genomic, transcriptomic and methylation studies have revealed differences between Mtb lineages, likely to impact on transmission, virulence and drug resistance. However, so far no studies have integrated sequence-based genomic, transcriptomic and methylation characterisation across a common set of samples, which is critical to understand how DNA sequence and methylation affect RNA expression and, ultimately, Mtb pathogenesis. Here we perform such an integrated analysis across 22 M. tuberculosis clinical isolates, representing ancient (lineage 1) and modern (lineages 2 and 4) strains. The results confirm the presence of lineage-specific differential gene expression, linked to specific SNP-based expression quantitative trait loci: with 10 eQTLs involving SNPs in promoter regions or transcriptional start sites; and 12 involving potential functional impairment of transcriptional regulators. Methylation status was also found to have a role in transcription, with evidence of differential expression in 50 genes across lineage 4 samples. Lack of methylation was associated with three novel variants in mamA, likely to cause loss of function of this enzyme. Overall, our work shows the relationship of DNA sequence and methylation to RNA expression, and differences between ancient and modern lineages. Further studies are needed to verify the functional consequences of the identified mechanisms of gene expression regulation

    Flows and cohesion: balancing capabilities across an expanded union

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    The dynamics of physical relocation of intellectual capital is seen in the flow of skilled workers across international boundaries and the internal movements within the increasingly integrated economy of the European Union. This article describes a research framework developed within the context of a globalised economy and its potential application to issues within the boundaries of the European Unio

    Paying Refugees to Leave

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    States are increasingly paying refugees to repatriate, hoping to decrease the number of refugees residing within their borders. Drawing on in-depth interviews from East Africa and data from Israeli Labour Statistics, I provide a description of such payment schemes and consider whether they are morally permissible. In doing so, I address two types of cases. In the first type of case, governments pay refugees to repatriate to high-risk countries, never coercing them into returning. I argue that such payments are permissible if refugees’ choices are voluntary and if states allow refugees to return to the host country in the event of an emergency. I then describe cases where states detain refugees, and non-governmental organisations provide their own payments to refugees wishing to repatriate. In such cases, non-governmental organisations are only permitted to provide payments if the funds are sufficient to ensure post-return safety and if providing payments does not reinforce the government’s detention policy

    Niche stiffness underlies the ageing of central nervous system progenitor cells.

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    Ageing causes a decline in tissue regeneration owing to a loss of function of adult stem cell and progenitor cell populations1. One example is the deterioration of the regenerative capacity of the widespread and abundant population of central nervous system (CNS) multipotent stem cells known as oligodendrocyte progenitor cells (OPCs)2. A relatively overlooked potential source of this loss of function is the stem cell 'niche'-a set of cell-extrinsic cues that include chemical and mechanical signals3,4. Here we show that the OPC microenvironment stiffens with age, and that this mechanical change is sufficient to cause age-related loss of function of OPCs. Using biological and synthetic scaffolds to mimic the stiffness of young brains, we find that isolated aged OPCs cultured on these scaffolds are molecularly and functionally rejuvenated. When we disrupt mechanical signalling, the proliferation and differentiation rates of OPCs are increased. We identify the mechanoresponsive ion channel PIEZO1 as a key mediator of OPC mechanical signalling. Inhibiting PIEZO1 overrides mechanical signals in vivo and allows OPCs to maintain activity in the ageing CNS. We also show that PIEZO1 is important in regulating cell number during CNS development. Thus we show that tissue stiffness is a crucial regulator of ageing in OPCs, and provide insights into how the function of adult stem and progenitor cells changes with age. Our findings could be important not only for the development of regenerative therapies, but also for understanding the ageing process itself.The work was supported by European Research Council (ERC) grant 772798 (to K.J.C.) and 772426 (to K.F.); the UK Multiple Sclerosis Society (to R.J.M.F.); Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/M008827/1 (to K.J.C and R.J.M.F.) and BB/N006402/1 (to K.F.); the Adelson Medical Research Foundation (R.J.M.F. and D.H.R.); an EMBO Long-Term Fellowship ALTF 1263-2015 and European Commission FP7 actions LTFCOFUND2013, GA-2013-609409 (to I.P.W.); and a core support grant from the Wellcome Trust and Medical Research Council (MRC) to the Wellcome Trust–MRC Cambridge Stem Cell Institute
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