2,303 research outputs found

    An antibody raised against a pathogenic serpin variant induces mutant-like behaviour in the wild-type protein.

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    A monoclonal antibody (mAb) that binds to a transient intermediate may act as a catalyst for the corresponding reaction; here we show this principle can extend on a macro-molecular scale to the induction of mutant-like oligomerisation in a wild-type protein. Using the common, pathogenic Glu342Lys (Z) variant of α1-antitrypsin as antigen - whose native state is susceptible to the formation of a proto-oligomeric intermediate - we have produced a mAb (5E3) that increases the rate of oligomerisation of the wild-type (M) variant. Employing ELISA, gel shift, thermal stability and FRET time-course experiments, we show that mAb5E3 does not bind to the native state of α1-antitrypsin, but recognises a cryptic epitope in the vicinity of the post-helix A loop and strand 4C that is revealed upon transition to the polymerisation intermediate, and which persists in the ensuing oligomer. This epitope is not shared by loop-inserted monomeric conformations. We show the increased amenity to polymerisation by either the pathogenic Glu342Lys mutation or the binding of mAb5E3 occurs without affecting energetic barrier to polymerisation. As mAb5E3 also does not alter the relative stability of the monomer to intermediate, it acts in a manner similar to the Glu342Lys mutation, by facilitating the conformational interchange between these two states

    Why national health research systems matter

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    Some of the most outstanding problems in Computer Science (e.g. access to heterogeneous information sources, use of different e-commerce standards, ontology translation, etc.) are often approached through the identification of ontology mappings. A manual mapping generation slows down, or even makes unfeasible, the solution of particular cases of the aforementioned problems via ontology mappings. Some algorithms and formal models for partial tasks of automatic generation of mappings have been proposed. However, an integrated system to solve this problem is still missing. In this paper, we present AMON, a platform for automatic ontology mapping generation. First of all, we show the general structure. Then, we describe the current version of the system, including the ontology in which it is based, the similarity measures that it uses, the access to external sources, etc

    An antibody raised against a pathogenic serpin variant induces mutant-like behaviour in the wild-type protein

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    A monoclonal antibody (mAb) that binds to a transient intermediate may act as a catalyst for the corresponding reaction; here we show this principle can extend on a macro molecular scale to the induction of mutant-like oligomerization in a wild-type protein. Using the common pathogenic E342K (Z) variant of α1-antitrypsin as antigen-whose native state is susceptible to the formation of a proto-oligomeric intermediate-we have produced a mAb (5E3) that increases the rate of oligomerization of the wild-type (M) variant. Employing ELISA, gel shift, thermal stability and FRET time-course experiments, we show that mAb5E3 does not bind to the native state of α1-antitrypsin, but recognizes a cryptic epitope in the vicinity of the post-helix A loop and strand 4C that is revealed upon transition to the polymerization intermediate, and which persists in the ensuing oligomer. This epitope is not shared by loop-inserted monomeric conformations. We show the increased amenity to polymerization by either the pathogenic E342K mutation or the binding of mAb5E3 occurs without affecting the energetic barrier to polymerization. As mAb5E3 also does not alter the relative stability of the monomer to intermediate, it acts in a manner similar to the E342K mutant, by facilitating the conformational interchange between these two states

    Massasauga Repatriation on a Restored Wet Prairie

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    The massasauga (Sistrurus catenatus) is a small rattlesnake that occurs from Texas to New York (Schmidt and Davis 1941, Conant and Collins 1991, Szymanski 1998). In Missouri, the Eastern massasauga rattlesnake (EMR; S. c. catenatus), a subspecies of the massasauga, occurs north and east of the Missouri River, is a former candidate for listing under the United States Endangered Species Act (Code of Federal Regulations 64 FR 57534; Szymanski 1998), and is listed as a state endangered species (Missouri Natural Heritage Program 2011). Missouri currently harbors five extant EMR populations (Johnson 2000, Durbian et al., unpublished report, J. Briggler, Missouri Department of Conservation, personal communication). The decline of this subspecies can be attributed to habitat loss and fragmentation, over utilization for commercial, recreational, scientific or educational purposes, predation due to habitat fragmentation, inadequacy of existing regulatory mechanisms, and indiscriminant or accidental killing (Szymanski 1988). In Missouri, the EMR utilizes a combination of mesic and xeric bottomland prairie habitats and is typically associated with wetlands (Seigel 1986, Johnson et al. 2000). Over the past century, 87% of the wetland habitat has been lost in Missouri (Dahl 1990); however, current restoration efforts will enable EMRs to repatriate sites that are adjacent to existing populations. Repatriation of restored habitat has been documented for many other species groups including amphibians (Lehtinen and Galatowitsch 2001) and birds (Gardali et al. 2006), however, we were unable to find evidence in the literature involving snakes. Therefore, our objective was to document repatriation of restored habitat by EMRs on Squaw Creek National Wildlife Refuge (SCNWR) located in northwestern Missouri

    Once-Daily Triple Therapy in Patients with COPD: Patient-Reported Symptoms and Quality of Life.

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    INTRODUCTION: Directly recorded patient experience of symptoms and health-related quality of life (HRQoL) can complement lung function and exacerbation rate data in chronic obstructive pulmonary disease (COPD) clinical studies. The FULFIL study recorded daily symptoms and activity limitation together with additional patient-reported outcomes of dyspnea and HRQoL, as part of the prespecified analyses. FULFIL co-primary endpoint data have been previously reported. METHODS: FULFIL was a phase III, 24-week, randomized, double-blind, double-dummy, multicenter study comparing once-daily single inhaler triple therapy [fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI)] 100 µg/62.5 µg/25 µg with twice-daily inhaled corticosteroid/long-acting β2-agonist therapy [budesonide/formoterol (BUD/FOR)] 400 µg/12 µg in patients with symptomatic COPD at risk of exacerbations. A subset participated for 52 weeks. Patient-reported assessments were: Evaluating Respiratory Symptoms in COPD™ (E-RS: COPD), St George's Respiratory Questionnaire (SGRQ) for COPD, COPD Assessment Test (CAT), baseline and transitional dyspnea indices (TDI) and daily and global anchor questions for activity limitation. RESULTS: FF/UMEC/VI showed greater reductions from baseline in 4-weekly mean E-RS: COPD total and all subscale scores compared with BUD/FOR; differences were statistically significant (P < 0.05) at each time period. FF/UMEC/VI also demonstrated greater improvements from baseline at weeks 4 and 24 in SGRQ domain scores and TDI focal score compared with BUD/FOR. At weeks 4 and 24, improvements greater than the minimal clinically important difference from baseline were observed in CAT score with FF/UMEC/VI, but not BUD/FOR; differences were statistically significant (P ≤ 0.003). CONCLUSION: These findings demonstrate sustained daily symptom and HRQoL benefits of FF/UMEC/VI versus BUD/FOR. The inclusion of the CAT may provide data that are readily generalizable to everyday clinical practice. TRIAL REGISTRATION: ClinicalTrials.gov number: NCT02345161. FUNDING: GSK

    Subtractive NCE-MRA: Improved background suppression using robust regression-based weighted subtraction.

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    PURPOSE: To correct the intensity difference of static background signal between bright blood images and dark blood images in subtractive non-contrast-enhanced MR angiography using robust regression, thereby improving static background signal suppression on subtracted angiograms. METHODS: Robust regression (RR), using iteratively reweighted least squares, is used to calculate the regression coefficient of background tissues from a scatter plot showing the voxel intensity of bright blood images versus dark blood images. The weighting function is based on either the Euclidean distance from the estimated regression line or the deviation angle. Results from RR using the deviation angle (RRDA), conventional RR using the Euclidean distance, and ordinary leastsquares regression were compared with reference values determined manually by two observers. Performance was evaluated over studies using different sequences, including 36 thoracic flow-sensitive dephasing data sets, 13 iliac flow-sensitive dephasing data sets, and 26 femoral fresh blood imaging data sets. RESULTS: RR deviation angle achieved robust and accurate performance in all types of images, with small bias, small mean absolute error, and high-correlation coefficients with reference values. Background tissues, such as muscle, veins, and bladder, were suppressed while the vascular signal was preserved. Euclidean distance gave good performance for thoracic and iliac flow-sensitive dephasing, but could not suppress background tissues in femoral fresh blood imaging. Ordinary least squares regression was sensitive to outliers and overestimated regression coefficients in thoracic flow-sensitive dephasing. CONCLUSION: Weighted subtraction using RR was able to acquire the regression coefficients of background signal and improve background suppression of subtractive non-contrast-enhanced MR angiography techniques. RR deviation angle has the most robust and accurate overall performance among three regression methods

    Innovation and opportunity: review of the UK’s national AI strategy

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    The publication of the UK’s National Artificial Intelligence (AI) Strategy represents a step-change in the national industrial, policy, regulatory, and geo-strategic agenda. Although there is a multiplicity of threads to explore this text can be read primarily as a ‘signalling’ document. Indeed, we read the National AI Strategy as a vision for innovation and opportunity, underpinned by a trust framework that has innovation and opportunity at the forefront. We provide an overview of the structure of the document and offer an emphasised commentary on various standouts. Our main takeaways are: Innovation First: a clear signal is that innovation is at the forefront of UK’s data priorities. Alternative Ecosystem of Trust: the UK’s regulatory-market norms becoming the preferred ecosystem is dependent upon the regulatory system and delivery frameworks required. Defence, Security and Risk: security and risk are discussed in terms of utilisation of AI and governance. Revision of Data Protection: the signal is that the UK is indeed seeking to position itself as less stringent regarding data protection and necessary documentation. EU Disalignment—Atlanticism?: questions are raised regarding a step back in terms of data protection rights. We conclude with further notes on data flow continuity, the feasibility of a sector approach to regulation, legal liability, and the lack of a method of engagement for stakeholders. Whilst the strategy sends important signals for innovation, achieving ethical innovation is a harder challenge and will require a carefully evolved framework built with appropriate expertise

    The molecular species responsible for α₁‐antitrypsin deficiency are suppressed by a small molecule chaperone

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    The formation of ordered Z (Glu342Lys) α1‐antitrypsin polymers in hepatocytes is central to liver disease in α1‐antitrypsin deficiency. In vitro experiments have identified an intermediate conformational state (M*) that precedes polymer formation but this has yet to be identified in vivo. Moreover, the mechanism of polymer formation and their fate in cells have been incompletely characterised. We have used cell models of disease in conjunction with conformation‐selective monoclonal antibodies and a small molecule inhibitor of polymerization to define the dynamics of polymer formation, accumulation and secretion. Pulse‐chase experiments demonstrate that Z α1‐antitrypsin accumulates as short chain polymers that partition with soluble cellular components and are partially secreted by cells. These precede the formation of larger, insoluble polymers with a longer half‐life (10.9 +/‐ 1.7 h and 20.9 +/ 7.4 h for soluble and insoluble polymers respectively). The M* intermediate (or a byproduct thereof) was identified in the cells by a conformation‐specific monoclonal antibody. This was completely abrogated by treatment with the small molecule which also blocked the formation of intracellular polymers. These data allow us to conclude that: the M* conformation is central to polymerization of Z α1‐antitrypsin in vivo; preventing its accumulation represents a tractable approach for pharmacological treatment of this condition; polymers are partially secreted; and polymers exist as two distinct populations in cells whose different dynamics have likely consequences for the aetiology of the disease
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