623 research outputs found

    Protein disulfide isomerase activity is essential for viability and extracellular matrix formation in the nematode Caenorhabditis elegans.

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    Protein disulfide isomerase (PDI) is a multifunctional protein required for many aspects of protein folding and transit through the endoplasmic reticulum. A conserved family of three PDIs have been functionally analysed using genetic mutants of the model organism Caenorhabditis elegans. PDI-1 and PDI-3 are individually nonessential, whereas PDI-2 is required for normal post-embryonic development. In combination, all three genes are synergistically essential for embryonic development in this nematode. Mutations in pdi-2 result in severe body morphology defects, uncoordinated movement, adult sterility, abnormal molting and aberrant collagen deposition. Many of these phenotypes are consistent with a role in collagen biogenesis and extracellular matrix formation. PDI-2 is required for the normal function of prolyl 4-hydroxylase, a key collagen-modifying enzyme. Site-directed mutagenesis indicates that the independent catalytic activity of PDI-2 may also perform an essential developmental function. PDI-2 therefore performs two critical roles during morphogenesis. The role of PDI-2 in collagen biogenesis can be partially restored following complementation of the mutant with human PDI

    Approximate Semantic Matching Over Linked Data Streams

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    In the Internet of Things (IoT),data can be generated by all kinds of smart things. In such context, enabling machines to process and understand such data is critical. Semantic Web technologies, such as Linked Data, provide an effective and machine-understandable way to represent IoT data for further processing. It is a challenging issue to match Linked Data streams semantically based on text similarity as text similarity computation is time consuming. In this paper, we present a hashing-based approximate approach to efficiently match Linked Data streams with users’ needs. We use the Resource Description Framework (RDF) to represent IoT data and adopt triple patterns as user queries to describe users’ data needs. We then apply locality-sensitive hashing techniques to transform semantic data into numerical values to support efficient matching between data and user queries. We design a modified k nearest neighbors (kNN) algorithm to speedup the matching process. The experimental results show that our approach is up to five times faster than the traditional methods and can achieve high precisions and recalls

    Prolyl 4-hydroxlase activity is essential for development and cuticle formation in the human infective parasitic nematode Brugia malayi

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    Collagen prolyl 4-hydroxylases (C-P4H) are required for formation of extracellular matrices in higher eukaryotes. These enzymes convert proline residues within the repeat regions of collagen polypeptides to 4-hydroxyproline, a modification essential for the stability of the triple helix. C-P4Hs are most often oligomeric complexes, with enzymatic activity contributed by the α subunits, and the β subunits formed by protein disulfide isomerase (PDI). Here we characterise this enzyme class in the important human parasitic nematode Brugia malayi. All potential C-P4H subunits were identified by detailed bioinformatic analysis of sequence databases, function was investigated both by RNAi in the parasite and heterologous expression in Caenorhabditis elegans, while biochemical activity and complex formation were examined via co-expression in insect cells. Simultaneous RNAi of two B. malayi C-P4H α subunit-like genes resulted in a striking, highly penetrant body morphology phenotype in parasite larvae. This was replicated by single RNAi of a B. malayi C-P4H β subunit-like PDI. Surprisingly however, the B. malayi proteins were not capable of rescuing a C. elegans α subunit mutant, whereas the human enzymes could. In contrast, the B. malayi PDI did functionally complement the lethal phenotype of a C. elegans β subunit mutant. Comparison of recombinant and parasite derived material indicates that enzymatic activity may be dependent on a non-reducible, inter-subunit cross-link, present only in the parasite. We therefore demonstrate that C-P4H activity is essential for development of B. malayi and uncover a novel parasite-specific feature of these collagen biosynthetic enzymes that may be exploited in future parasite control

    Waiting times for radiotherapy: variation over time and between cancer networks in southeast England

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    The aim of this study was to investigate variations in the length of time that patients with cancer wait from diagnosis to treatment with radiotherapy. A total of 57 426 men and 71 018 women diagnosed with cancer between 1992 and 2001 and receiving radiotherapy within 6 months of diagnosis were identified from the Thames Cancer Registry database. In total, 12 sites were identified for which a substantial number or proportion of patients received radiotherapy: head and neck, oesophagus, colon, rectum, lung, nonmelanoma skin cancer, breast, uterus, prostate, bladder, brain and non-Hodgkin's lymphoma. Median waiting times from diagnosis to radiotherapy were calculated, together with the proportion of patients who received radiotherapy within 60 days of diagnosis, and analysed by year of diagnosis, cancer site, deprivation quintile, age at diagnosis, sex and cancer network of either residence or treatment. Logistic regression was used to adjust the proportion receiving treatment within 60 days for the effects of the other factors. There were significant differences in the proportions receiving radiotherapy within 60 days between different networks and different cancer sites, which remained after adjustment. Median waiting times varied from 42 to 65 days across networks of residence, with the adjusted proportion treated within 60 days ranging from 44 to 71%. There was no difference between male and female patients after adjustment for the other factors, particularly site. There was a highly significant trend over time: the median wait increased from 45 days in 1992 to 76 days in 2001, while the adjusted proportion being treated within 60 days declined by almost a half, from 64 to 35%, over the same period

    High-throughput identification of genotype-specific cancer vulnerabilities in mixtures of barcoded tumor cell lines.

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    Hundreds of genetically characterized cell lines are available for the discovery of genotype-specific cancer vulnerabilities. However, screening large numbers of compounds against large numbers of cell lines is currently impractical, and such experiments are often difficult to control. Here we report a method called PRISM that allows pooled screening of mixtures of cancer cell lines by labeling each cell line with 24-nucleotide barcodes. PRISM revealed the expected patterns of cell killing seen in conventional (unpooled) assays. In a screen of 102 cell lines across 8,400 compounds, PRISM led to the identification of BRD-7880 as a potent and highly specific inhibitor of aurora kinases B and C. Cell line pools also efficiently formed tumors as xenografts, and PRISM recapitulated the expected pattern of erlotinib sensitivity in vivo

    Dementia Wristband Report

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    This research project explored the use of new wearable and mobile technologies to support independent living and social interactions in the community for people living with dementia and their carers, more safely and for longer. The three key aims of the project were to: • Assess the potential acceptability, and usability of a mobile phone App and wearable wristband solution • Test the use of the technological in the everyday life contexts • Evaluate the usability and utility of a mobile phone App and digital wristband to reduce social isolation and improve health outcomes The research project had two stages: Stage 1 - Acceptability, utility and usability of the devices This stage of the project focused on developing initial understandings of the ways in which the proposed technological solutions work and potentially meet the needs of people living with dementia and their carers. This was achieved through: - Technology testing by the project team members. This gave the team a better understanding of the device used in the project. - Interviews with people with dementia and their carers, and with health and social care professionals. The interviews explored whether participants were receptive to, and what they thought about, the proposed solutions. Any concerns they had about the tracking technology in general or about the technology used in the project were also examined. Stage 2: Real world testing of the wristbands and smartphone App Research participant’s trialled the technology, as part of their everyday lives, for up to three months. During this period the research team worked closely with them to provide training and technological support and used a multi-method data collection focused on semi-structured interviews and observation to capture their experiences of using the technology. The participants living with dementia and their carers were given the opportunity to choose the technology that best suits them, either a wristbands or a smartphone application. Key findings In summary, through the interviews and focus groups and real world technology testing the research team and SME partners found there are issues around: - the use of technology for people living with dementia and their carers – for some people it was seen as a real benefit, others did not want to engage with the technology or have others know where they were. - education, information and support for people living with dementia and their carers to use new technologies; even when delivered via familiar technologies this can be challenging and needs support and time - support for family/other carers who are key to the support of mobile and wearable technologies. - support for people who do not have a local or remote family carer who can support the use of new technologies needs to be considered. - current GPS technologies not being accurate as a stand alone way of finding someone who may be lost or needing support. - safeguarding – which needs to take an holistic approach and include more traditional and ‘paper based’ safeguarding systems such as the Herbert protocol, - emerging and new technologies, which are developing constantly but a national approach is still missing; - the challenges for unpaid carers and people living with dementia to around exploring options around new technologies and deciding what are the best/cost effective options for their situations. - wearable and mobile technologies which can support people to be more independent in the community, but the technologies need to be: introduced early; affordable and be more easily supported by family and professional care givers as appropriate

    An unbiased in vitro screen for activating epidermal growth factor receptor mutations

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    Cancer tissues harbor thousands of mutations, and a given oncogene may be mutated at hundreds of sites. Yet, only a few of these mutations have been functionally tested. Here, we describe an unbiased platform for the functional characterization of thousands of variants of a single receptor tyrosine kinase (RTK) gene in a single assay. Our in vitro screen for activating mutations (iSCREAM) platform enabled rapid analysis of mutations conferring gain-of-function RTK activity promoting clonal growth. The screening strategy included a somatic model of cancer evolution and utilized a library of 7,216 randomly mutated epidermal growth factor receptor (EGFR) single-nucleotide variants, that were tested in murine lymphoid Ba/F3 cells. These cells depend on exogenous interleukin-3 (IL-3) for growth, but this dependency can be compensated by ectopic EGFR overexpression, enabling selection for gain-of-function EGFR mutants. Analysis of the enriched mutants revealed EGFR A702V, a novel activating variant that structurally stabilized the EGFR kinase dimer interface and conferred sensitivity to kinase inhibition by afatinib. As proof of concept for our approach, we recapitulated clinical observations and identified the EGFR L858R as the major enriched EGFR variant. Altogether iSCREAM enabled robust enrichment of 21 variants from a total of 7,216 EGFR mutations. These findings indicate the power of this screening platform for unbiased identification of activating RTK variants that are enriched under selection pressure in a model of cancer heterogeneity and evolution
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