1,082 research outputs found

    The ASCC2 CUE domain in the ALKBH3-ASCC DNA repair complex recognizes adjacent ubiquitins in K63-linked polyubiquitin

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    Alkylation of DNA and RNA is a potentially toxic lesion that can result in mutations and even cell death. In response to alkylation damage, K63-linked polyubiquitin chains are assembled that localize the Alpha-ketoglutarate-dependent dioxygenase alkB homolog 3-Activating Signal Cointegrator 1 Complex Subunit (ASCC) repair complex to damage sites in the nucleus. The protein ASCC2, a subunit of the ASCC complex, selectively binds K63-linked polyubiquitin chains via its coupling of ubiquitin conjugation to ER degradation (CUE) domain. The basis for polyubiquitin-binding specificity was unclear, because CUE domains in other proteins typically bind a single ubiquitin and do not discriminate among different polyubiquitin linkage types. We report here that the ASCC2 CUE domain selectively binds K63-linked diubiquitin by contacting both the distal and proximal ubiquitin. The ASCC2 CUE domain binds the distal ubiquitin in a manner similar to that reported for other CUE domains bound to a single ubiquitin, whereas the contacts with the proximal ubiquitin are unique to ASCC2. Residues in the N-terminal portion of the ASCC2 α1 helix contribute to the binding interaction with the proximal ubiquitin of K63-linked diubiquitin. Mutation of residues within the N-terminal portion of the ASCC2 α1 helix decreases ASCC2 recruitment in response to DNA alkylation, supporting the functional significance of these interactions during the alkylation damage response. Our study reveals the versatility of CUE domains in ubiquitin recognition

    An extended Krylov-like method for the solution of multi-linear systems

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    In the present work, numerical methods for the solution of multi-linear system are presented. Most large-scale multi-linear solvers rely on either the alternating leastsquares or low rank Krylov methods. The approach we use to develop our methods lies somehow in between and can be considered as a generalisation of an alternated direction method. Given the multi-linear operator in the form of a sum of Kronecker product of matrices, we solve at each iteration a linear system for each summand. The approximate solution is then defined to be the best linear combination of these solutions, as well as the previous solution and the residual. Some convergence results are proved. Numerical experiments on two problems arising from parametric PDEs show the effectiveness of the proposed method

    Successful synthesis of a glial-specific blood-brain barrier shuttle peptide following a fragment condensation approach on a solid-phase resin

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    Successful manual synthesis of the TD2.2 peptide acting as a blood-brain barrier shuttle was achieved. TD2.2 was successfully synthesised by sequential condensation of four protected peptide fragments on solid-phase settings, after several unsuccessful attempts using the stepwise approach. These fragments were chosen to minimize the number of demanding amino acids (in terms of coupling, Fmoc removal) in each fragment that are expected to hamper the overall synthetic process. Thus, the hydrophobic amino acids as well as Fmoc-Arg (Pbf)-OH were strategically spread over multiple fragments rather than having them congested in one fragment. This study shows how a peptide that shows big challenges in the synthesis using the common stepwise elongation methodology can be synthesised with an acceptable purity. It also emphasises that choosing the right fragment with certain amino acid constituents is key for a successful synthesis. It is worth highlighting that lower amounts of reagents were required to synthesise the final peptide with an identical purity to that obtained by the automatic synthesiser

    Application of carbon nanotubes in cancer vaccines: Achievements, challenges and chances

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    Tumour-specific, immuno-based therapeutic interventions can be considered as safe and effective approaches for cancer therapy. Exploitation of nano-vaccinology to intensify the cancer vaccine potency may overcome the need for administration of high vaccine doses or additional adjuvants and therefore could be a more efficient approach. Carbon nanotube (CNT) can be described as carbon sheet(s) rolled up into a cylinder that is nanometers wide and nanometers to micrometers long. Stemming from the observed capacities of CNTs to enter various types of cells via diversified mechanisms utilising energy-dependent and/or passive routes of cell uptake, the use of CNTs for the delivery of therapeutic agents has drawn increasing interests over the last decade. Here we review the previous studies that demonstrated the possible benefits of these cylindrical nano-vectors as cancer vaccine delivery systems as well as the obstacles their clinical application is facing

    APPLICATION OF IMMERSIVE TECHNOLOGIES IN THE EARLY DESIGN STAGE IN ARCHITECTURE EDUCATION - A SYSTEMATIC REVIEW

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    This paper reviews existing research on the use of immersive technologies, Virtual Reality in particular, in various stages of the architectural design process. Nine research papers were systematically reviewed and analyzed. They were filtered down by using the keywords: ‘Virtual/Augmented Reality, Architectural Education, Gravity Sketch, Unity and Virtual Environments’ from two main databases that focus on digital and computer-aided design research: Cumulative Index about publications in Computer Aided Architectural Design (CuminCAD) and Elsevier\u27s abstract and citation database (Scopus). The selection of papers was filtered down based on relevant approaches which investigate architectural design, creative thinking and teaching methodology using immersive technologies. Another criterion applied to the filtering process of the research papers is the exploration and integration process of new tools and overlapping external software to aid the existing workflow of the user. Our findings explore the evolution of immersive tools to highlight the advantages and disadvantages of virtual reality-based software and hardware, as a creative development tool in the field of education and practice. This paper also proposes a novel teaching methodology that incorporates immersive technologies in the early design phase of architectural education

    Effect of an edge at cup rim on contact stress during micro-separation in ceramic-on-ceramic hip joints

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    Alumina ceramic total hip joint bearings have shown superior wear properties. The joint bearing may undergo adverse conditions such as micro-separation causing head contact on the cup rim. As a transition, an edge is formed between the cup bearing and the rim. The aim of this study was to predict the effect of the edge on contact stresses in order to better understand the mechanisms of wear. A finite element contact model was developed under the conditions of the head displacements 0.5 2 mm and vertical loads 0.5 3kN. The edge contact produced the most severe stresses capable of causing elevated wear and damage to ceramic bearings. The study shows that the bearing design should be considered in association with clinical conditions to eliminate severe stress

    MR-IMPACT: comparison of perfusion-cardiac magnetic resonance with single-photon emission computed tomography for the detection of coronary artery disease in a multicentre, multivendor, randomized trial

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    Aims To determine in a multicentre, multivendor trial the diagnostic performance for perfusion-cardiac magnetic resonance (perfusion-CMR) in comparison with coronary X-ray angiography (CXA) and single-photon emission computed tomography (SPECT). Methods and results Of 241 eligible patients from 18 centres, 234 were randomly dosed with 0.01, 0.025, 0.05, 0.075, or 0.1 mmol/kg Gd-DTPA-BMA (Omniscan™, GE-Healthcare) per stress (0.42 mg/kg adenosine) and rest perfusion study. Coronary artery disease (CAD) was defined as diameter stenosis ≥50% on quantitative CXA. Five CMR and eight SPECT studies (of 225 complete studies) were excluded from analyses due to inadequate quality (three blinded readers scored per modality). The comparison of CMR vs. SPECT was based on receiver operating characteristic (ROC) analysis. Perfusion-CMR at the optimal CM dose (0.1 mmol/kg) had similar performance as SPECT, if only the SPECT studies of the 42 patients with this dose were considered [area under ROC curve (AUC): 0.86 ± 0.06 vs. 0.75 ± 0.09 for SPECT, P = 0.12]; however, diagnostic performance of perfusion-CMR was better vs. the entire SPECT population (AUC: 0.67 ± 0.05, n = 212, P = 0.013). Conclusions In this multicentre, multivendor trial, ROC analyses suggest perfusion-CMR as a valuable alternative to SPECT for CAD detection showing equal performance in the head-to-head comparison. Comparing perfusion-CMR with the entire SPECT population suggests CMR superiority over SPECT, which warrants further evaluation in larger trial

    Regulatory T Cell Extracellular Vesicles Modify T-Effector Cell Cytokine Production and Protect Against Human Skin Allograft Damage

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    Regulatory T cells (Tregs) are a subpopulation of CD4⁺ T cells with a fundamental role in maintaining immune homeostasis and inhibiting unwanted immune responses using several different mechanisms. Recently, the intercellular transfer of molecules between Tregs and their target cells has been shown via trogocytosis and the release of small extracellular vesicles (sEVs). In this study, CD4⁺CD25⁺CD127ˡᵒ human Tregs were found to produce sEVs capable of inhibiting the proliferation of effector T cells (Teffs) in a dose dependent manner. These vesicles also modified the cytokine profile of Teffs leading to an increase in the production of IL-4 and IL-10 whilst simultaneously decreasing the levels of IL-6, IL-2, and IFNγ. MicroRNAs found enriched in the Treg EVs were indirectly linked to the changes in the cytokine profile observed. In a humanized mouse skin transplant model, human Treg derived EVs inhibited alloimmune-mediated skin tissue damage by limiting immune cell infiltration. Taken together, Treg sEVs may represent an exciting cell-free therapy to promote transplant survival

    Determination of 35 cell surface antigen levels in malignant pleural effusions identifies CD24 as a marker of disseminated tumor cells

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    Many targets have been identified in solid tumors for antibody therapy but it is less clear what surface antigens may be most commonly expressed on disseminated tumor cells. Using malignant pleural effusions as a source of disseminated tumor cells, we compared a panel of 35 antigens for their cancer specificity, antigen abundance and functional significance. These antigens have been previously implicated in cancer metastasis and fall into four categories: (i) cancer stem cell, (ii) epithelial-mesenchymal transition, (iii) metastatic signature of in vivo selection and (iv) tyrosine kinase receptors. We determined the antigen density of all 35 antigens on the cell surface by flow cytometry, which ranges from 3 × 10[superscript 3]–7 × 10[superscript 6] copies per cell. Comparison between the malignant and benign pleural effusions enabled us to determine the antigens specific for cancer. We further chose six antigens and examined the correlation between their expression levels and tumor formation in immunocompromised mice. We concluded that CD24 is one of the few antigens that could simultaneously meet all three criteria of an ideal target. It was specifically and abundantly expressed in malignant pleural effusions; CD24[superscript high] tumor cells formed tumors in mice at a faster rate than CD24[superscript low] tumor cells, and shRNA-mediated knockdown of CD24 in HT29 cells confirmed a functional requirement for CD24 in the colonization of the lung. Concomitant consideration of antigen abundance, specificity and functional importance can help identify potentially useful markers for disseminated tumor cells
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