27 research outputs found

    Deciphering the complex three-way interaction between the non-integrin laminin receptor, galectin-3 and Neisseria meningitidis

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    The non-integrin laminin receptor (LAMR1/RPSA) and galectin-3 (Gal-3) are multi-functional host molecules with roles in diverse pathological processes, particularly of infectious or oncogenic origins. Using bimolecular fluorescence complementation and confocal imaging, we demonstrate that the two proteins homo- and heterodimerize, and that each isotype forms a distinct cell surface population. We present evidence that the 37 kDa form of LAMR1 (37LRP) is the precursor of the previously described 67 kDa laminin receptor (67LR), whereas the heterodimer represents an entity that is distinct from this molecule. Site-directed mutagenesis confirmed that the single cysteine (C173) of Gal-3 or lysine (K166) of LAMR1 are critical for heterodimerization. Recombinant Gal-3, expressed in normally Gal-3-deficient N2a cells, dimerized with endogenous LAMR1 and led to a significantly increased number of internalized bacteria (Neisseria meningitidis), confirming the role of Gal-3 in bacterial invasion. Contact-dependent cross-linking determined that, in common with LAMR1, Gal-3 binds the meningococcal secretin PilQ, in addition to the major pilin PilE. This study adds significant new mechanistic insights into the bacterial–host cell interaction by clarifying the nature, role and bacterial ligands of LAMR1 and Gal-3 isotypes during colonization

    Sentinel surveillance for human enterovirus 71 in Sarawak, Malaysia: lessons from the first 7 years

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    BACKGROUND: A major outbreak of human enterovirus 71-associated hand, foot and mouth disease in Sarawak in 1997 marked the beginning of a series of outbreaks in the Asia Pacific region. Some of these outbreaks had unusually high numbers of fatalities and this generated much fear and anxiety in the region. METHODS: We established a sentinel surveillance programme for hand, foot and mouth disease in Sarawak, Malaysia, in March 1998, and the observations of the first 7 years are described here. Virus isolation, serotyping and genotyping were performed on throat, rectal, vesicle and other swabs. RESULTS: During this period Sarawak had two outbreaks of human enterovirus 71, in 2000 and 2003. The predominant strains circulating in the outbreaks of 1997, 2000 and 2003 were all from genogroup B, but the strains isolated during each outbreak were genetically distinct from each other. Human enterovirus 71 outbreaks occurred in a cyclical pattern every three years and Coxsackievirus A16 co-circulated with human enterovirus 71. Although vesicles were most likely to yield an isolate, this sample was not generally available from most cases and obtaining throat swabs was thus found to be the most efficient way to obtain virological information. CONCLUSION: Knowledge of the epidemiology of human enterovirus 71 transmission will allow public health personnel to predict when outbreaks might occur and to plan interventions in an effective manner in order to reduce the burden of disease

    Identification of novel breast cancer susceptibility loci in meta-analyses conducted among Asian and European descendants

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    Abstract: Known risk variants explain only a small proportion of breast cancer heritability, particularly in Asian women. To search for additional genetic susceptibility loci for breast cancer, here we perform a meta-analysis of data from genome-wide association studies (GWAS) conducted in Asians (24,206 cases and 24,775 controls) and European descendants (122,977 cases and 105,974 controls). We identified 31 potential novel loci with the lead variant showing an association with breast cancer risk at P < 5 × 10−8. The associations for 10 of these loci were replicated in an independent sample of 16,787 cases and 16,680 controls of Asian women (P < 0.05). In addition, we replicated the associations for 78 of the 166 known risk variants at P < 0.05 in Asians. These findings improve our understanding of breast cancer genetics and etiology and extend previous findings from studies of European descendants to Asian women

    Speculative parallel simulation with an adaptive throttle scheme

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    Proceedings Workshop on Parallel and Distributed Simulation116-12320

    Metastectomy for non-colorectal, non-neuroendocrine liver secondaries

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    Background: The role of metastectomy for colorectal and neuroendocrine liver secondaries is well established. Significant palliation and survival have been reported after aggressive surgical resection. However, the role of liver resection for secondaries from other primary tumours is less well defined. In this study, we aim to describe our experience, including indications and selection criteria, operative strategy and clinical outcome of liver resection, for non-colorectal, non-neuroendocrine liver metastases. Methods: A review of prospectively collected operative database was conducted and patients who underwent liver resection of secondaries from non-colorectal, non-neuroendocrine primary tumours were studied. Eighteen patients were included in the study. There were 4 men and 14 women with a median age of 48 years (range, 37–78 years). Liver resection was carried out either for cure or for palliation of debilitating symptoms. Selection criteria included: (i) absence of extrahepatic disease and (ii) functional status of the liver and volume of remnant liver after hepatectomy. The median follow up was 24 months (range, 7–81 months) for 17 patients, excluding the one who defaulted after surgery. Cancer-specific survival and recurrence-free interval was calculated from the date of hepatectomy. Results: Liver resection was considered curative in 13 patients. There was no 30-day mortality in this cohort of patients. The median recurrence-free survival time was 13 months (95 confidence interval (CI), 8–18 months). The median follow-up time for the 12 patients was 23.5 months (range, 7–35 months). Only five patients died due to cancer-specific causes and one died from acute myocardial infarction. The median cancer-specific survival time was 30 months (95 CI, 25–35 months). The 2-year survival rate was 77.1 (95 CI, 48.9–100). Conclusion: The results are encouraging and suggest that with appropriate selection criteria, there is a role for metastectomy of non-colorectal, non-neuroendocrine liver secondaries

    Myeloperoxidase inhibition may protect against endothelial glycocalyx shedding induced by COVID-19 plasma

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    Abstract Background SARS-CoV-2, the causative agent of COVID-19, is a threat to public health. Evidence suggests increased neutrophil activation and endothelial glycocalyx (EG) damage are independently associated with severe COVID-19. Here, we hypothesised that an increased level of blood neutrophil myeloperoxidase (MPO) is associated with soluble EG breakdown, and inhibiting MPO activity may reduce EG damage. Methods Analysing a subset of acute and convalescent COVID-19 plasma, 10 from severe and 15 from non-severe COVID-19 cases, and 9 from pre-COVID-19 controls, we determined MPO levels, MPO activity and soluble EG proteins (syndecan-1 and glypican-1) levels by enzyme-linked immunosorbent assay. In vitro primary human aortic endothelial cells were cultured with plasma untreated or treated with specific MPO inhibitors (MPO-IN-28, AZD5904) to determine EG shedding. We then investigated whether inhibiting MPO activity decreased EG degradation. Results In COVID-19 plasma, MPO levels, MPO activity and levels of soluble EG proteins are significantly raised compared to controls, and concentrations increase in proportion to disease severity. Despite clinical recovery, protein concentrations remain significantly elevated. Interestingly, there is a trend of increasing MPO activity in convalescent plasma in both severe and non-severe groups. MPO levels and MPO activity correlate significantly with soluble EG levels and inhibiting MPO activity leads to reduced syndecan-1 shedding, in vitro. Conclusions Neutrophil MPO may increase EG shedding in COVID-19, and inhibiting MPO activity may protect against EG degradation. Further research is needed to evaluate the utility of MPO inhibitors as potential therapeutics against severe COVID-19

    A Sensitive Method for Detecting Zika Virus Antigen in Patients' Whole-Blood Specimens as an Alternative Diagnostic Approach

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    Background Epidemics caused by the reemergence of Zika virus (ZIKV) warrant the need to develop new diagnostic measures to complement currently used detection methods. In this study, we explored the detection of ZIKV antigen in a defined leukocyte subset from patients’ whole-blood specimens. Methods Whole-blood samples were obtained at the acute and early convalescent phases from ZIKV-infected patients during the Singapore outbreak in August–September 2016. Presence of ZIKV antigen was determined by flow cytometry staining for intracellular ZIKV NS3, using a ZIKV-specific polyclonal antibody. The presence of ZIKV antigen was determined in CD45+CD14+ monocytes. Results Data showed that ZIKV NS3 antigen could be detected in CD45+CD14+ monocytes. The levels of detection were further categorized into 3 groups: high (positivity among >40% of monocytes), moderate (positivity among 10%–40%), and low (positivity among <10%). While a majority of patients showed a decrease in the amount of ZIKV antigen detected at later time points, some patients displayed higher levels as the disease progressed. Conclusions Our data highlights an alternative approach in using flow cytometry as a sensitive method for detecting ZIKV antigen in whole blood. Importantly, it further confirms the role of CD14+ monocytes as an important cellular target for ZIKV infection during the viremic phase
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