134 research outputs found

    Sequentially based analysis versus image based analysis of Intima Media Thickness in common carotid arteries studies - Do major IMT studies underestimate the true relations for cardio- and cerebrovascular risk?

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    <p>Abstract</p> <p>Background</p> <p>Image-based B-mode ultrasound has gained popularity in major studies as a non-invasive method of measuring cardio- and cerebrovascular risk factors. However, none of the major studies appears to have paid sufficient attention to the variation in end diastolic wall process. By using sequentially based analyses (SBA) of Intima-Media Thickness (IMT), the general purpose of this study was to show that the current image based (ECG tracked) analysis (IBA) has some major variations and might underestimate the true relations for cardiovascular events and stroke for IMT measurement.</p> <p>Method</p> <p>The study group consisted of 2500 healthy male subjects aged between 35 to 55 years. 4 sequences (300 images) were analyzed per subject. 750,000 images were analysed throughout the course of this study.</p> <p>Results</p> <p>IBA showed significantly lower mean, maximal, and minimal values for IMT in CCA than for SBA. The correlation analysis between IBA and SBA with the cardio- and cerebrovascular risk factors showed a higher correlation of SBA for all risk factors. The Pearson coefficient was 0.81, p < 0.01, for SBA versus Framingham CHD risk level (FCRL) and 0.49, p = 0.01, for IBA versus FCRL.</p> <p>Conclusion</p> <p>IBA did not measure the true maximal values of the IMT in this study. Together with the correlation analysis, this indicates that IBA might underestimate the true relations for IMT and risk factors.</p

    The Intracellular Transport and Secretion of Calumenin-1/2 in Living Cells

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    Calumenin isoforms 1 and 2 (calu-1/2), encoded by the CALU gene, belong to the CREC protein family. Calu-1/2 proteins are secreted into the extracellular space, but the secretory process and regulatory mechanism are largely unknown. Here, using a time-lapse imaging system, we visualized the intracellular transport and secretory process of calu-1/2-EGFP after their translocation into the ER lumen. Interestingly, we observed that an abundance of calu-1/2-EGFP accumulated in cellular processes before being released into the extracellular space, while only part of calu-1/2-EGFP proteins were secreted directly after attaching to the cell periphery. Moreover, we found the secretion of calu-1/2-EGFP required microtubule integrity, and that calu-1/2-EGFP-containing vesicles were transported by the motor proteins Kif5b and cytoplasmic dynein. Finally, we determined the export signal of calu-1/2-EGFP (amino acid positions 20–46) and provided evidence that the asparagine at site 131 was indispensable for calu-1/2-EGFP stabilization. Taken together, we provide a detailed picture of the intracellular transport of calu-1/2-EGFP, which facilitates our understanding of the secretory mechanism of calu-1/2

    Reduced microvascular density in omental biopsies of children with chronic kidney disease

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    Endothelial dysfunction is an early manifestation of cardiovascular disease (CVD) and consistently observed in patients with chronic kidney disease (CKD). We hypothesized that CKD is associated with systemic damage to the microcirculation, preceding macrovascular pathology. To assess the degree of "uremic microangiopathy", we have measured microvascular density in biopsies of the omentum of children with CKD.Omental tissue was collected from 32 healthy children (0-18 years) undergoing elective abdominal surgery and from 23 age-matched cases with stage 5 CKD at the time of catheter insertion for initiation of peritoneal dialysis. Biopsies were analyzed by independent observers using either a manual or an automated imaging system for the assessment of microvascular density. Quantitative immunohistochemistry was performed for markers of autophagy and apoptosis, and for the abundance of the angiogenesis-regulating proteins VEGF-A, VEGF-R2, Angpt1 and Angpt2.Microvascular density was significantly reduced in uremic children compared to healthy controls, both by manual imaging with a digital microscope (median surface area 0.61% vs. 0.95%, p<0.0021 and by automated quantification (total microvascular surface area 0.89% vs. 1.17% p = 0.01). Density measured by manual imaging was significantly associated with age, height, weight and body surface area in CKD patients and healthy controls. In multivariate analysis, age and serum creatinine level were the only independent, significant predictors of microvascular density (r2 = 0.73). There was no immunohistochemical evidence for apoptosis or autophagy. Quantitative staining showed similar expression levels of the angiogenesis regulators VEGF-A, VEGF-receptor 2 and Angpt1 (p = 0.11), but Angpt2 was significantly lower in CKD children (p = 0.01).Microvascular density is profoundly reduced in omental biopsies of children with stage 5 CKD and associated with diminished Angpt2 signaling. Microvascular rarefaction could be an early systemic manifestation of CKD-induced cardiovascular disease

    Tracking seasonal changes in North Sea zooplankton trophic dynamics using stable isotopes

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    Trophodynamics of meso-zooplankton in the North Sea (NS) were assessed at a site in the southern NS, and at a shallow and a deep site in the central NS. Offshore and neritic species from different ecological niches, including Calanus spp., Temora spp. and Sagitta spp., were collected during seven cruises over 14 months from 2007 to 2008. Bulk stable isotope (SI) analysis, phospholipid-derived fatty acid (PLFA) compositions, and δ 13CPLFA data of meso-zooplankton and particulate organic matter (POM) were used to describe changes in zooplankton relative trophic positions (RTPs) and trophodynamics. The aim of the study was to test the hypothesis that the RTPs of zooplankton in the North Sea vary spatially and seasonally, in response to hydrographic variability, with the microbial food web playing an important role at times. Zooplankton RTPs tended to be higher during winter and lower during the phytoplankton bloom in spring. RTPs were highest for predators such as Sagitta sp. and Calanus helgolandicus and lowest for small copepods such as Pseudocalanus elongatus and zoea larvae (Brachyura). δ 15NPOM-based RTPs were only moderate surrogates for animals’ ecological niches, because of the plasticity in source materials from the herbivorous and the microbial loop food web. Common (16:0) and essential (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) structural lipids showed relatively constant abundances. This could be explained by incorporation of PLFAs with δ 13C signatures which followed seasonal changes in bulk δ 13CPOM and PLFA δ 13CPOM signatures. This study highlighted the complementarity of three biogeochemical approaches for trophodynamic studies and substantiated conceptual views of size-based food web analysis, in which small individuals of large species may be functionally equivalent to large individuals of small species. Seasonal and spatial variability was also important in altering the relative importance of the herbivorous and microbial food webs

    An early history of T cell-mediated cytotoxicity.

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    After 60 years of intense fundamental research into T cell-mediated cytotoxicity, we have gained a detailed knowledge of the cells involved, specific recognition mechanisms and post-recognition perforin-granzyme-based and FAS-based molecular mechanisms. What could not be anticipated at the outset was how discovery of the mechanisms regulating the activation and function of cytotoxic T cells would lead to new developments in cancer immunotherapy. Given the profound recent interest in therapeutic manipulation of cytotoxic T cell responses, it is an opportune time to look back on the early history of the field. This Timeline describes how the early findings occurred and eventually led to current therapeutic applications

    Search for strongly interacting massive particles generating trackless jets in proton-proton collisions at s = 13 TeV

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    A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 16.1 fb - 1 , collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100 GeV are excluded and further sensitivity is explored towards higher masses

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
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