150 research outputs found

    Continuation-Passing C: compiling threads to events through continuations

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    In this paper, we introduce Continuation Passing C (CPC), a programming language for concurrent systems in which native and cooperative threads are unified and presented to the programmer as a single abstraction. The CPC compiler uses a compilation technique, based on the CPS transform, that yields efficient code and an extremely lightweight representation for contexts. We provide a proof of the correctness of our compilation scheme. We show in particular that lambda-lifting, a common compilation technique for functional languages, is also correct in an imperative language like C, under some conditions enforced by the CPC compiler. The current CPC compiler is mature enough to write substantial programs such as Hekate, a highly concurrent BitTorrent seeder. Our benchmark results show that CPC is as efficient, while using significantly less space, as the most efficient thread libraries available.Comment: Higher-Order and Symbolic Computation (2012). arXiv admin note: substantial text overlap with arXiv:1202.324

    Pre-hospital administration of ticagrelor in diabetic patients with ST-elevation myocardial infarction undergoing primary angioplasty: A sub-analysis of the ATLANTIC trial

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    Objective: We investigated, in the contemporary era of ST-elevation myocardial infarction (STEMI) treatment, the influence of diabetes mellitus (DM) on cardiovascular outcomes, and whether pre-hospital administration of ticagrelor may affect these outcomes in a subgroup of STEMI patients with DM. Background: DM patients have high platelet reactivity and a prothrombotic condition which highlight the importance of an effective antithrombotic regimen in this high-risk population. Methods: In toal 1,630 STEMI patients enrolled in the ATLANTIC trial who underwent primary percutaneous coronary intervention (PCI) were included. Multivariate analysis was used to explore the association of DM with outcomes and potential treatment-by-diabetes interaction was tested. Results: A total of 214/1,630 (13.1%) patients had DM. DM was an independent predictor of poor myocardial reperfusion as reflected by less frequent ST-segment elevation resolution ( 6570%) after PCI (OR 0.59, 95% CI 0.43\u20130.82, P < 0.01) and was an independent predictor of the composite 30-day outcomes of death/new myocardial infarction (MI)/urgent revascularization/definite stent thrombosis (ST) (OR 2.80, 95% CI 1.62\u20134.85, P < 0.01), new MI or definite acute ST (OR 2.46, 95% CI 1.08\u20135.61, P = 0.03), and definite ST (OR 10.00, 95% CI 3.54\u201328.22, P < 0.01). No significant interaction between pre-hospital ticagrelor vs in-hospital ticagrelor administration and DM was present for the clinical, electrocardiographic and angiographic outcomes as well as for thrombolysis in myocardial infarction major bleeding. Conclusions: DM remains independently associated with poor myocardial reperfusion and worse 30-day clinical outcomes. No significant interaction was found between pre-hospital vs in-hospital ticagrelor administration and DM status. Further approaches for the treatment of DM patients are needed. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT01347580

    An ex-vivo Human Intestinal Model to Study Entamoeba histolytica Pathogenesis

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    Amoebiasis (a human intestinal infection affecting 50 million people every year) is caused by the protozoan parasite Entamoeba histolytica. To study the molecular mechanisms underlying human colon invasion by E. histolytica, we have set up an ex vivo human colon model to study the early steps in amoebiasis. Using scanning electron microscopy and histological analyses, we have established that E. histolytica caused the removal of the protective mucus coat during the first two hours of incubation, detached the enterocytes, and then penetrated into the lamina propria by following the crypts of Lieberkühn. Significant cell lysis (determined by the release of lactodehydrogenase) and inflammation (marked by the secretion of pro-inflammatory molecules such as interleukin 1 beta, interferon gamma, interleukin 6, interleukin 8 and tumour necrosis factor) were detected after four hours of incubation. Entamoeba dispar (a closely related non-pathogenic amoeba that also colonizes the human colon) was unable to invade colonic mucosa, lyse cells or induce an inflammatory response. We also examined the behaviour of trophozoites in which genes coding for known virulent factors (such as amoebapores, the Gal/GalNAc lectin and the cysteine protease 5 (CP-A5), which have major roles in cell death, adhesion (to target cells or mucus) and mucus degradation, respectively) were silenced, together with the corresponding tissue responses. Our data revealed that the signalling via the heavy chain Hgl2 or via the light chain Lgl1 of the Gal/GalNAc lectin is not essential to penetrate the human colonic mucosa. In addition, our study demonstrates that E. histolytica silenced for CP-A5 does not penetrate the colonic lamina propria and does not induce the host's pro-inflammatory cytokine secretion

    Lactobacillaceae and Cell Adhesion: Genomic and Functional Screening

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    The analysis of collections of lactic acid bacteria (LAB) from traditional fermented plant foods in tropical countries may enable the detection of LAB with interesting properties. Binding capacity is often the main criterion used to investigate the probiotic characteristics of bacteria. In this study, we focused on a collection of 163 Lactobacillaceace comprising 156 bacteria isolated from traditional amylaceous fermented foods and seven strains taken from a collection and used as controls. The collection had a series of analyses to assess binding potential for the selection of new probiotic candidates. The presence/absence of 14 genes involved in binding to the gastrointestinal tract was assessed. This enabled the detection of all the housekeeping genes (ef-Tu, eno, gap, groEl and srtA) in the entire collection, of some of the other genes (apf, cnb, fpbA, mapA, mub) in 86% to 100% of LAB, and of the other genes (cbsA, gtf, msa, slpA) in 0% to 8% of LAB. Most of the bacteria isolated from traditional fermented foods exhibited a genetic profile favorable for their binding to the gastrointestinal tract. We selected 30 strains with different genetic profiles to test their binding ability to non-mucus (HT29) and mucus secreting (HT29-MTX) cell lines as well as their ability to degrade mucus. Assays on both lines revealed high variability in binding properties among the LAB, depending on the cell model used. Finally, we investigated if their binding ability was linked to tighter cross-talk between bacteria and eukaryotic cells by measuring the expression of bacterial genes and of the eukaryotic MUC2 gene. Results showed that wild LAB from tropical amylaceous fermented food had a much higher binding capacity than the two LAB currently known to be probiotics. However their adhesion was not linked to any particular genetic equipment

    Microfold (M) cells: important immunosurveillance posts in the intestinal epithelium

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    The transcytosis of antigens across the gut epithelium by microfold cells (M cells) is important for the induction of efficient immune responses to some mucosal antigens in Peyer’s patches. Recently, substantial progress has been made in our understanding of the factors that influence the development and function of M cells. This review highlights these important advances, with particular emphasis on: the host genes which control the functional maturation of M cells; how this knowledge has led to the rapid advance in our understanding of M-cell biology in the steady-state and during aging; molecules expressed on M cells which appear to be used as “immunosurveillance” receptors to sample pathogenic microorganisms in the gut; how certain pathogens appear to exploit M cells to infect the host; and finally how this knowledge has been used to specifically target antigens to M cells to attempt to improve the efficacy of mucosal vaccines

    Enhancing Oral Vaccine Potency by Targeting Intestinal M Cells

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    The immune system in the gastrointestinal tract plays a crucial role in the control of infection, as it constitutes the first line of defense against mucosal pathogens. The attractive features of oral immunization have led to the exploration of a variety of oral delivery systems. However, none of these oral delivery systems have been applied to existing commercial vaccines. To overcome this, a new generation of oral vaccine delivery systems that target antigens to gut-associated lymphoid tissue is required. One promising approach is to exploit the potential of microfold (M) cells by mimicking the entry of pathogens into these cells. Targeting specific receptors on the apical surface of M cells might enhance the entry of antigens, initiating the immune response and consequently leading to protection against mucosal pathogens. In this article, we briefly review the challenges associated with current oral vaccine delivery systems and discuss strategies that might potentially target mouse and human intestinal M cells

    Imidazole propionate is increased in diabetes and associated with dietary patterns and altered microbial ecology

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    Microbiota-host-diet interactions contribute to the development of metabolic diseases. Imidazole propionate is a novel microbially produced metabolite from histidine, which impairs glucose metabolism. Here, we show that subjects with prediabetes and diabetes in the MetaCardis cohort from three European countries have elevated serum imidazole propionate levels. Furthermore, imidazole propionate levels were increased in subjects with low bacterial gene richness and Bacteroides 2 enterotype, which have previously been associated with obesity. The Bacteroides 2 enterotype was also associated with increased abundance of the genes involved in imidazole propionate biosynthesis from dietary histidine. Since patients and controls did not differ in their histidine dietary intake, the elevated levels of imidazole propionate in type 2 diabetes likely reflects altered microbial metabolism of histidine, rather than histidine intake per se. Thus the microbiota may contribute to type 2 diabetes by generating imidazole propionate that can modulate host inflammation and metabolism

    The Rotterdam Study: 2012 objectives and design update

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    The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods
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