43 research outputs found

    Relationship between treatment delay and final infarct size in STEMI patients treated with abciximab and primary PCI

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    Background Studies on the impact of time to treatment on myocardial infarct size have yielded   conflicting results. In this study of ST-Elevation Myocardial Infarction (STEMI) treated   with primary percutaneous coronary intervention (PCI), we set out to investigate the   relationship between the time from First Medical Contact (FMC) to the demonstration   of an open infarct related artery (IRA) and final scar size. Between February 2006 and September 2007, 89 STEMI patients treated with primary PCI   were studied with contrast enhanced magnetic resonance imaging (ceMRI) 4 to 8 weeks   after the infarction. Spearman correlation was computed for health care delay time   (defined as time from FMC to PCI) and myocardial injury. Multiple linear regression   was used to determine covariates independently associated with infarct size. Results An occluded artery (Thrombolysis In Myocardial Infarction, TIMI flow 0-1 at initial   angiogram) was seen in 56 patients (63%). The median FMC-to-patent artery was 89 minutes.   There was a weak correlation between time from FMC-to-patent IRA and infarct size,   r = 0.27, p = 0.01. In multiple regression analyses, LAD as the IRA, smoking and an occluded vessel   at the first angiogram, but not delay time, correlated with infarct size. Conclusions In patients with STEMI treated with primary PCI we found a weak correlation between   health care delay time and infarct size. Other factors like anterior infarction, a   patent artery pre-PCI and effects of reperfusion injury may have had greater influence   on infarct size than time-to-treatment per se

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Development of the nervous system in Solenogastres (Mollusca) reveals putative ancestral spiralian features

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    Background: The Solenogastres (or Neomeniomorpha) are a taxon of aplacophoran molluscs with contentious phylogenetic placement. Since available developmental data on non-conchiferan (that is, aculiferan) molluscs mainly stem from polyplacophorans, data on aplacophorans are needed to clarify evolutionary questions concerning the morphological features of the last common ancestor (LCA) of the Aculifera and the entire Mollusca. We therefore investigated the development of the nervous system in two solenogasters, Wirenia argentea and Gymnomenia pellucida, using immunocytochemistry and electron microscopy. Results: Nervous system formation starts simultaneously from the apical and abapical pole of the larva with the development of a few cells of the apical organ and a posterior neurogenic domain. A pair of neurite bundles grows out from both the neuropil of the apical organ and the posterior neurogenic domain. After their fusion in the region of the prototroch, which is innervated by an underlying serotonin-like immunoreactive (−LIR) plexus, the larva exhibits two longitudinal neurite bundles - the future lateral nerve cords. The apical organ in its fully developed state exhibits approximately 8 to 10 flask-shaped cells but no peripheral cells. The entire ventral nervous system, which includes a pair of longitudinal neurite bundles (the future ventral nerve cords) and a serotonin-LIR ventromedian nerve plexus, appears simultaneously and is established after the lateral nervous system. During metamorphosis the apical organ and the prototrochal nerve plexus are lost. Conclusions: The development of the nervous system in early solenogaster larvae shows striking similarities to other spiralians, especially polychaetes, in exhibiting an apical organ with flask-shaped cells, a single pair of longitudinal neurite bundles, a serotonin-LIR innervation of the prototroch, and formation of these structures from an anterior and a posterior neurogenic domain. This provides evidence for an ancestral spiralian pattern of early nervous system development and a LCA of the Spiralia with a single pair of nerve cords. In later nervous system development, however, the annelids deviate from all other spiralians including solenogasters in forming a posterior growth zone, which initiates teloblastic growth. Since this mode of organogenesis is confined to annelids, we conclude that the LCA of both molluscs and spiralians was unsegmented

    Comparative transcriptomics enlarges the toolkit of known developmental genes in mollusks

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    Mollusks display a striking morphological disparity, including, among others, worm-like animals (the aplacophorans), snails and slugs, bivalves, and cephalopods. This phenotypic diversity renders them ideal for studies into animal evolution. Despite being one of the most species-rich phyla, molecular and in silico studies concerning specific key developmental gene families are still scarce, thus hampering deeper insights into the molecular machinery that governs the development and evolution of the various molluscan class-level taxa. Results: Next-generation sequencing was used to retrieve transcriptomes of representatives of seven out of the eight recent class-level taxa of mollusks. Similarity searches, phylogenetic inferences, and a detailed manual curation were used to identify and confirm the orthology of numerous molluscan Hox and ParaHox genes, which resulted in a comprehensive catalog that highlights the evolution of these genes in Mollusca and other metazoans. The identification of a specific molluscan motif in the Hox paralog group 5 and a lophotrochozoan ParaHox motif in the Gsx gene is described. Functional analyses using KEGG and GO tools enabled a detailed description of key developmental genes expressed in important pathways such as Hedgehog, Wnt, and Notch during development of the respective species. The KEGG analysis revealed Wnt8, Wnt11, and Wnt16 as Wnt genes hitherto not reported for mollusks, thereby enlarging the known Wnt complement of the phylum. In addition, novel Hedgehog (Hh)-related genes were identified in the gastropod Lottia cf. kogamogai, demonstrating a more complex gene content in this species than in other mollusks. Conclusions: The use of de novo transcriptome assembly and well-designed in silico protocols proved to be a robust approach for surveying and mining large sequence data in a wide range of non-model mollusks. The data presented herein constitute only a small fraction of the information retrieved from the analysed molluscan transcriptomes, which can be promptly employed in the identification of novel genes and gene families, phylogenetic inferences, and other studies using molecular tools. As such, our study provides an important framework for understanding some of the underlying molecular mechanisms involved in molluscan body plan diversification and hints towards functions of key developmental genes in molluscan morphogenesis.Peer Reviewe

    Aplacophoran mollusks evolved from ancestors with polyplacophoran-like features

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    Mollusca is an animal phylum with vast morphological diversity and includes worm-shaped aplacophorans, snails, bivalves, and the complex cephalopods [1]. The interrelationships of these class-level taxa are still contentious [2 and 3], but recent phylogenomic analyses suggest a dichotomy at the base of Mollusca, resulting in a monophyletic Aculifera (comprising the shell-less, sclerite-bearing aplacophorans and the eight-shelled polyplacophorans) and Conchifera (all other, primarily univalved groups) [4 and 5]. The Aculifera concept has recently gained support via description of the fossil Kulindroplax, which shows both aplacophoran- and polyplacophoran-like features and suggests that the aplacophorans originated from a shelled ancestor [ 6], but the overall morphology of the last common aculiferan ancestor remains obscure. Here we show that larvae of the aplacophoran Wirenia argentea have several sets of muscles previously known only from polyplacophoran mollusks. Most of these are lost during metamorphosis, and we interpret them as ontogenetic remnants of an ancestor with a complex, polyplacophoran-like musculature. Moreover, we find that the first seven pairs of dorsoventral muscles develop synchronously in Wirenia, similar to juvenile polyplacophorans [ 7], which supports the conclusions based on the seven-shelled Kulindroplax. Accordingly, we argue that the simple body plan of recent aplacophorans is the result of simplification and does not represent a basal molluscan condition
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