1,195 research outputs found

    Solution structure of human thioredoxin in a mixed disulfide intermediate complex with its target peptide from the transcription factor NFÎşB

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    AbstractBackground: Human thioredoxin is a 12 kDa cellular redox protein that plays a key role in maintaining the redox environment of the cell. It has recently been shown to be responsible for activating the DNA-binding properties of the cellular transcription factor, NFκB, by reducing a disulfide bond involving Cys62 of the p50 subunit. Using multidimensional heteronuclear-edited and heteronuclear-filtered NMR spectroscopy, we have solved the solution structure of a complex of human thioredoxin and a 13-residue peptide extending from residues 56–68 of p50, representing a kinetically stable mixed disulfide intermediate along the reaction pathway.Results The NFκB peptide is located in a long boot-shaped cleft on the surface of human thioredoxin delineated by the active-site loop, helices α2, α3 and α4, and strands β3 and β4. The peptide adopts a crescent-like conformation with a smooth 110° bend centered around residue 60 which permits it to follow the path of the cleft.Conclusion In addition to the intermolecular disulfide bridge between Cys32 of human thioredoxin and Cys62 of the peptide, the complex is stabilized by numerous hydrogen-bonding, electrostatic and hydrophobic interactions which involve residues 57–65 of the NFκB peptide and confer substrate specificity. These structural features permit one to suggest the specificity requirements for human thioredoxin-catalyzed disulfide bond reduction of proteins

    Ventral root re-implantation is better than peripheral nerve transplantation for motoneuron survival and regeneration after spinal root avulsion injury

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    A knowledge-based design advisory system for collaborative design for micromanufacturing

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    The manufacture of microproducts differs from that of conventional products in many ways, not only in the sizes, but also in issues concerning the effects of material properties, tools, and manufacturing equipment. There was a need for a new design methodology and associated design tools to aid designers in assessing the design of their microproducts by considering new micromanufacturing capabilities and constraints. A knowledge-based design advisory system (DAS) was, therefore, developed in MASMICRO in which the knowledge-based system with dedicated assessment modules and knowledge representatives based on the ontology was created to implement the distributed design and manufacturing assessment for micromanufacturing. The modules address the assessment on geometrical features relating to manufacturability, manufacturing processes, selection of materials, tools, and machines, as well as manufacturing cost. The Microsoft C# programming language, ASP.NET web technology, Prolog, and Microsoft Access database were used to develop the DAS. The test on the DAS prototype system was found to provide an increase of design efficiency due to more efficient use of design and manufacturing knowledge and afforded a web-based collaborative design environment

    SMART: Unique splitting-while-merging framework for gene clustering

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    Copyright @ 2014 Fa et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Successful clustering algorithms are highly dependent on parameter settings. The clustering performance degrades significantly unless parameters are properly set, and yet, it is difficult to set these parameters a priori. To address this issue, in this paper, we propose a unique splitting-while-merging clustering framework, named “splitting merging awareness tactics” (SMART), which does not require any a priori knowledge of either the number of clusters or even the possible range of this number. Unlike existing self-splitting algorithms, which over-cluster the dataset to a large number of clusters and then merge some similar clusters, our framework has the ability to split and merge clusters automatically during the process and produces the the most reliable clustering results, by intrinsically integrating many clustering techniques and tasks. The SMART framework is implemented with two distinct clustering paradigms in two algorithms: competitive learning and finite mixture model. Nevertheless, within the proposed SMART framework, many other algorithms can be derived for different clustering paradigms. The minimum message length algorithm is integrated into the framework as the clustering selection criterion. The usefulness of the SMART framework and its algorithms is tested in demonstration datasets and simulated gene expression datasets. Moreover, two real microarray gene expression datasets are studied using this approach. Based on the performance of many metrics, all numerical results show that SMART is superior to compared existing self-splitting algorithms and traditional algorithms. Three main properties of the proposed SMART framework are summarized as: (1) needing no parameters dependent on the respective dataset or a priori knowledge about the datasets, (2) extendible to many different applications, (3) offering superior performance compared with counterpart algorithms.National Institute for Health Researc

    Heterogeneity of Paucigranulocytic Asthma: A Prospective Cohort Study with Hierarchical Cluster Analysis.

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    BACKGROUND: Asthma, a heterogeneous disease, can be divided into 4 inflammatory phenotypes using induced sputum cell counts-eosinophilic asthma (EA), neutrophilic asthma (NA), mixed granulocytic asthma, and paucigranulocytic asthma (PGA). Although research has focused on EA and NA, there is little known about PGA. OBJECTIVE: To study the heterogeneity of PGA and identify possible PGA clusters to guide clinical treatment. METHODS: Patients with PGA were grouped by hierarchical cluster analysis and enrolled into a prospective cohort study to validate the clusters, relative to future risk of asthma exacerbations in a real-world setting. Clusters were validated by tree analysis in a separate population. Finally, we explored PGA stability. RESULTS: Cluster analysis of 145 patients with PGA identified 3 clusters: cluster 1 (n = 110, 75.9%) was "mild PGA," cluster 2 (n = 20, 13.8%) was "PGA with psychological dysfunction and rhinoconjunctivitis and other allergic diseases," and cluster 3 (n = 15, 10.3%) was "smoking-associated PGA." Cluster 3 had significantly increased risk of severe exacerbation (relative risk [RR] = 6.43, P = .01), emergency visit (RR = 8.61, P = .03), and hospitalization (RR = 12.94, P < .01). Results of the cluster analysis were successfully validated in an independent PGA population classified using decision tree analysis. Although PGA can transform into or develop from other phenotypes, 70% were stable over time. CONCLUSIONS: Among 3 identified PGA clusters, cluster 3 had a higher risk of severe exacerbation. PGA heterogeneity indicates the requirement of novel targeted interventions

    Alendronate increases BMD at appendicular and axial skeletons in patients with established osteoporosis

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    <p>Abstract</p> <p>Background</p> <p>To identify high-risk patients and provide pharmacological treatment is one of the effective approaches in prevention of osteoporotic fractures. This study investigated the effect of 12-month Alendronate treatment on bone mineral density (BMD) and bone turnover biochemical markers in postmenopausal women with one or more non-traumatic fractures, i.e. patients with established osteoporosis.</p> <p>Methods</p> <p>A total of 118 Hong Kong postmenopausal Chinese women aged 50 to 75 with low-energy fracture at distal radius (Colles' fracture) were recruited for BMD measurement at lumbar spine and non-dominant hip using Dual-Energy X-ray Absorptiometry (DXA). 47 women with BMD T-score below -2 SD at either side were identified as patients with established osteoporosis and then randomized into Alendronate group (n = 22) and placebo control group (n = 25) for BMD measurement at spine and hip using DXA and distal radius of the non-fracture side by peripheral quantitative computed tomography (pQCT), and bone turnover markers, including bone forming alkaline phosphatase (BALP) and bone resorbing urinary Deoxypyridinoline (DPD). All measurements were repeated at 6 and 12 months.</p> <p>Results</p> <p>Alendronate treatment significantly increased BMD, more in weight-bearing skeletons (5.1% at spine and 2.5% at hip) than in non-weight bearing skeleton (0.9% at distal radius) after 12 months treatment. Spine T-score was significant improved in Alendronate group (p < 0.01) (from -2.2 to -1.9) but not in control placebo group. The Alendronate treatment effect was explained by significant suppression of bone turnover.</p> <p>Conclusion</p> <p>12 months Alendronate treatment was effective to increase BMD at both axial and appendicular skeletons in postmenopausal women with established osteoporosis.</p

    Treatable Traits in Elderly Asthmatics from the Australasian Severe Asthma Network: A Prospective Cohort Study.

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    BACKGROUND: Data on treatable traits (TTs) in different populations are limited. OBJECTIVE: To assess TTs in elderly patients with asthma and compare them to younger patients, to evaluate the association of TTs with future exacerbations, and to develop an exacerbation prediction model. METHODS: We consecutively recruited 521 participants at West China Hospital, Sichuan University based on the Australasian Severe Asthma Network, classified as elderly (n = 62) and nonelderly (n = 459). Participants underwent a multidimensional assessment to characterize the TTs and were then followed up for 12 months. TTs and their relationship with future exacerbations were described. Based on the TTs and asthma control levels, an exacerbation prediction model was developed, and the overall performance was externally validated in an independent cohort. RESULTS: A total of 38 TTs were assessed. Elderly patients with asthma had more chronic metabolic diseases, fixed airflow limitation, emphysema, and neutrophilic inflammation, whereas nonelderly patients with asthma exhibited more allergic characteristics and psychiatric diseases. Nine traits were associated with increased future exacerbations, of which exacerbation prone, upper respiratory infection-induced asthma attack, cardiovascular disease, diabetes, and depression were the strongest. A model including exacerbation prone, psychiatric disease, cardiovascular disease, upper respiratory infection-induced asthma attack, noneosinophilic inflammation, cachexia, food allergy, and asthma control was developed to predict exacerbation risk and showed good performance. CONCLUSIONS: TTs can be systematically assessed in elderly patients with asthma, some of which are associated with future exacerbations, proving their clinical utility of evaluating them. A model based on TTs can be used to predict exacerbation risk in people with asthma
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