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Genetic and molecular characterisation of A Disintegrin and Metalloprotease (ADAM) 33
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Label-Free Differential Leukocyte Counts Using a Microfabricated, Single-Cell Impedance Spectrometer
No full textImpedance spectroscopy is a non-invasive technique which allows analysis of the electrical properties of biological cells and other materials. Typically, the electrical properties of a cell suspension are measured using relatively large volumes (>100 ?l). This approach suffers from the significant drawback that the measurement is averaged over several million cells, and as such, discrimination of cell sub-population and cell sorting is impossible. We have developed a microfluidic device capable of high-speed impedance analysis of individual cells in rapid succession. In this paper, we outline the theory for impedance analysis of a single cell in a microchip. We show experimentally, the ability of the technology to distinguish, based on impedance alone, the three main leukocyte (white blood cell) sub-populations (monocytes, lymphocytes, neutrophils) in human blood. Fluorescence analysis of the cells is performed simultaneously with impedance measurement, as cells flow through the device. This provides a direct correlation between cell type (based on antibody) and impedance properties. The data shows distinct differences in the impedance properties of leukocyte sub-populations at specific frequencies
The role of ADAM33 in the pathogenesis of asthma
No full textWhile asthma is a disorder of the conducting airways characterised by Th2-directed inflammation, a second set of mechanisms is being increasingly recognised as fundamental to disease chronicity and severity, for which the term "remodelling" has been used. The cellular and mediator responses underpinning airway remodelling involve aberrant communication between the airway epithelium and underlying mesenchyme, involving the generation of growth factors that lead to proliferation of fibroblasts and smooth muscle and the deposition of matrix proteins to cause airway wall thickening linked to bronchial hyperresponsiveness and fixed airflow obstruction. The identification of ADAM33 on chromosome 20p13 from positional cloning as a novel candidate gene involved in the pathogenesis of these structural and functional changes has opened the way to further insight into these processes that contribute to corticosteroid refractoriness. The preferential expression of ADAM33 in mesenchymal cells and its multiple molecular actions provide ample opportunity for incriminating this molecule in chronic asthma. Its association with progressive asthma and in predicting reduced lung function in young children suggest that ADAM33 has an important role in the natural history and possibly the origins of asthma, a disease unique to humans
ADAM 33 and its association with airway remodeling and hyperresponsiveness in asthma
No full textAsthma is known to be a Th2 inflammatory syndrome that leads to intermittent airway obstruction. However, the mechanisms involved in development of the clinical features remain enigmatic, although genetic elements clearly are involved. Recently, based on a large genomewide screen involving families in the United Kingdom and the United States with at least two siblings with asthma, a locus was identified that encoded for a family of proteases. This group of proteins is now known as the ADAM superfamily. In this review, we discuss the ADAM superfamily and, in particular, ADAM 33, a member of a family of genes which encode a subgroup of zinc dependent metalloproteinase (metzincin). The potential for therapeutic intervention with ADAM 33 is extremely attractive and further work will not only focus on the specific domains of ADAM 33, but also the mechanisms by which they lead to bronchial hyperreactivity
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Epigenetic mechanisms silence a disintegrin and metalloprotease 33 expression in bronchial epithelial cells
No full textBackground: A disintegrin and metalloprotease 33 (ADAM33) polymorphism is strongly associated with asthma and bronchial hyperresponsiveness.Although considered to be a mesenchymal cell–specific gene, recent reports have suggested epithelial expression of ADAM33 in patients with severe asthma.Objectives: Because dysregulated expression of ADAM33 can contribute to disease pathogenesis, we characterized the mechanism or mechanisms that control its transcription and investigated ADAM33 expression in bronchial biopsy specimens and brushings from healthy and asthmatic subjects.Methods: The ADAM33 promoter and CpG island methylation were analyzed by using bioinformatics, luciferase reporters, and bisulfite sequencing of genomic DNA. Epithelial-mesenchymal transition was induced by using TGF-b1. ADAM33 mRNA was scrutinized in bronchial biopsy specimens and brushings by using reverse transcriptase–quantitative polymerase chain reaction, melt-curve analysis, and direct sequencing.Results: The predicted ADAM33 promoter (2550 to 187) had promoter transcriptional activity. Bisulfite sequencing showed that the predicted promoter CpG island (2362 to 180) was hypermethylated in epithelial cells but hypomethylated in ADAM33-expressing fibroblasts.Treatment of epithelial cells with 5-aza-deoxycytidine caused demethylation of the CpG island and induced ADAM33 expression. In contrast, phenotypic transformation of epithelial cells through a TGF-b–induced epithelial mesenchymal transition was insufficient to induce ADAM33 expression. ADAM33 mRNA was confirmed in bronchial biopsy specimens, but no validated signal was detected in bronchial brushings from healthy or asthmatic subjects.Conclusion: The ADAM33 gene contains a regulatory CpG island within its promoter, the methylation status of which tightly controls its expression in a cell type–specific manner. ADAM33 repression is a stable feature of airway epithelial cells, irrespective of disease. (J Allergy Clin Immunol 2008;121:1393-9.
Exogenous IFN-? has antiviral and anti-inflammatory properties in primary bronchial epithelial cells from asthmatic subjects exposed to rhinovirus
No full textBackground: Rhinoviruses are the major cause of asthma exacerbations. Previous studies suggest that primary bronchial epithelial cells (PBECs) from asthmatic subjects are more susceptible to rhinovirus infection because of deficient IFN-? production. Although augmenting the innate immune response might provide a novel approach for treatment of virus-induced asthma exacerbations, the potential of IFN-? to modulate antiviral and proinflammatory responses in asthmatic epithelium is poorly characterized.Objectives: We sought to compare responses of PBECs from nonasthmatic and asthmatic subjects to exogenous IFN-? and test the inflammatory effects of IFN-? in response to rhinovirus infection.Methods: PBECs were treated with IFN-? and infected with a low inoculum of human rhinovirus serotype 1B to simulate a natural viral infection. Expression of interferon-responsive genes and inflammatory responses were analyzed by using reverse transcription–quantitative real-time PCR, cytometric bead arrays, or both; viral titers were assessed by using the 50% tissue culture infection dose.Results: Expression of IFN-?–stimulated antiviral genes was comparable in PBECs from nonasthmatic or asthmatic donors. Exogenous IFN-? significantly protected PBECs from asthmatic donors against rhinovirus infection by suppressing viral replication. Interferon-inducible protein 10 (IP-10), RANTES, and IL-6 release in response to rhinovirus infection was triggered only in PBECs from asthmatic donors. Although exogenous IFN-? alone stimulated some release of IP-10 (but not IL-6 or RANTES), it significantly reduced rhinovirus-induced IP-10, RANTES, and IL-6 expression when tested in combination with rhinovirus.Conclusions: PBECs from asthmatic donors have a normal antiviral response to exogenous IFN-?. The ability of IFN-? to suppress viral replication suggests that it might limit virus-induced exacerbations by shortening the duration of the inflammatory response
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