1,720,974 research outputs found
A biological model to explain the association between human rhinovirus respiratory infections and bronchial asthma
No full textHuman rhinoviruses (HRVs) are a frequent cause or upper respiratory tract infections in children and adults, and can exacerbate existing pulmonary disease. The major group of HRV attach to the receptor intercellular adhesion molecule (ICAM)-1, which is expressed on many cell types including epithelial cells. To study the influence of biological mediators on ICAM-1 expression, and consequently HRV attachment and infection, we have established an in vitro model system to evaluate the effects or pre-exposure to different cytokines on surface expression of ICAM-1 of uninfected and HRV-14-infected epithelial cells. The results of our studies show that the cytokines interleukin (IL)-1 beta, IL-8 and tumour necrosing factor (TNF)alpha increased ICAM-1 expression on epithelial cells. Epithelial cells infected with live HRV-14 displayed a significant upregulation of ICAM-1 compared to baseline. In contrast, interferon (IFN)gamma, whilst increasing the level of ICAM-1 expression on uninfected cells, induced a marked persistent downregulation of ICAM-1 expression on HRV-infected epithelial cells. In addition, IFN gamma appeared to completely override the ICAM-1 upregulation induced by IL-1 beta, IL-8 and TNF alpha, during HRV infection. We have further demonstrated that type 2 T-helper cell (Th2)-associated cytokines, predominantly IL-13, induce a marked upregulation or epithelial cell surface ICAM-1, thus increasing cellular binding sites for HRV attachment. As the airway mucosa or asthmatic subjects is predominantly infiltrated by activated type 2 T-helper cells with a simultaneous decrease of type 1 T-helper cells, our observations could explain the increased susceptibility to human rhinovirus infection observed in asthma.Human rhinoviruses (HRVs) are a frequent cause of upper respiratory tract infections in children and adults, and can exacerbate existing pulmonary disease. The major group of HRV attach to the receptor intercellular adhesion molecule (ICAM)-1, which is expressed on many cell types including epithelial cells. To study the influence of biological mediators on ICAM-1 expression, and consequently HRV attachment and infection, we have established an in vitro model system to evaluate the effects of pre-exposure to different cytokines on surface expression of ICAM-1 of uninfected and HRV-14-infected epithelial cells. The results of our studies show that the cytokines interleukin (IL)-1β, IL-8 and tumour necrosing factor (TNF)α increased ICAM-1 expression on epithelial cells. Epithelial cells infected with live HRV-14 displayed a significant upregulation of ICAM-1 compared to baseline. In contrast, interferon (IFN)γ, whilst increasing the level of ICAM-1 expression on uninfected cells, induced a marked persistent downregulation of ICAM-1 expression on HRV-infected epithelial cells. In addition, IFNγ appeared to completely override the ICAM-1 upregulation induced by IL-1β, IL-8 and TNFα, during HRV infection. We have further demonstrated that type 2 T-helper cell (Th2)-associated cytokines, predominantly IL-13, induce a marked upregulation of epithelial cell surface ICAM-1, thus increasing cellular binding sites for HRV attachment. As the airway mucosa of asthmatic subjects is predominantly infiltrated by activated type 2 T-helper cells with a simultaneous decrease of type 1 T-helper cells, our observations could explain the increased susceptibility to human rhinovirus infection observed in asthma
Effect of IL-4, IL-10, and IL-13 on manganese superoxide dismutase (MnSOD) expression in LPS-stimulated monocytoid cells
No full textPeripheral anergy and local immune hyperactivation in sarcoidosis: A paradox or birds of a feather
No full textInterferon-gamma (IFN-) induce de novo protein synthesis of both membrane and soluble intercellular adhesion molecule-1 in normal human bronchial epithelial cells
No full textDifferential effects of T-helper cell-associated cytokines on the expression of two forms of ICAM-1 receptor during HRV infection
No full textVirus-induced asthma
No full textClinical and experimental investigations indicate that respiratory viral infections are important triggers for asthma attacks. Viral upper respiratory infections have been associated with 80% of asthma exacerbations in children and 50% of all asthma episodes in adults. Human Rhinovirus (HRV) has been implicated as the most common virus associated with asthma episodes. The observation that the great majority of wheezing lower respiratory tract illnesses in early life are associated with acute viral infections suggests that viruses may also alter the development of the lungs or of the immune system, acting as co-factors for the inception of asthma. Whilst there is no doubt that viruses are important asthma exacerbation factors, the role of viral infections in the development of asthma still remains controversial
Th2 Cytokines, IL-4, IL-5, IL-13 upregulate ICAM-1 expression in rhinoviral-infected epithelial cells
No full text
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
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