1,721,093 research outputs found
Assessing bioflavonoids as regulators of NF-κB activity and inflammatory gene expression in mammalian cells
No full textInflammation is a multifactorial response that is of fundamental importance
in the maintenance of cellular homeostasis when the organism is challenged by
noxious agents (e.g., bacteria, viruses, parasites) or by tissue mechanical injury.
Inflammatory processes are associated with a dramatic rise in the number of polymorphonuclear
leukocytes and monocytes in the affected tissue and the subsequent
release of various molecules such as prostaglandins and cytokines. Under
ideal conditions, inflammation results in the complete recovery of the integrity
of the affected tissue. However, if the response of the triggering stimulus is not
subjected to a tight regulation, a condition known as chronic inflammation can
be established. Indeed, a chronic inflammatory-like environment characterizes the
pathogenesis of various diseases, such as atheriosclerosis, rheumatoid arthritis,and Crohn's disease, and is thought to be among the causative factor of more than
30% of human cancer.1
The transcription factor NF-KB, in cooperation with others, has been suggested
to coordinate the expression of genes encoding proteins that are involved
in inflammatory processes. In particular, NF-KB contributes to the production of
interleukin (IL)-I, IL-6, tumor necrosis factor (TNF)-et, lymphotoxin, GM-CSF,
and interferon (IFN)-~. Furthermore, some of these cytokines, e.g., IL-1 and TNFa,
activate NF-KB themselves, thus initiating an autoregulatory feedback loop. 2
NF-KB activation by various stimuli occurs on its dissociation from the inhibitory
protein I-KB and its subsequent nuclear translocation. Several lines of evidence,
including the inhibition by various antioxidants, suggest that NF-KB activity is
subject to redox regulation. 3 Because of the pivotal role in inflammatory response
a significant effort has focused on developing therapeutic agents that regulate NFKB
activity
Macrophages stimulated with IFN-gamma activate NF-kappa B and induce MCP-1 gene expression in primary human endothelial cells
No full textA novel coculture model was established to study the effects of reactive oxygen (ROS) and reactive nitrogen species (RNS) generated by RAW 264.7 macrophages on NF-kappa B activation and monocyte chemoattractant protein (MCP-1) gene expression in primary human endothelial cells (HUVEC). This model simulates free radical-mediated interactions occurring in the process of cardiovascular diseases. The coculture of macrophages grown on filters and stimulated by IFN-gamma-induced a pro-oxidant environment and resulted in increased DNA binding and NF-kappa B transactivation in HUVEC. Activation of NF-kappa B in endothelial cells was accompanied by an evident increase in the expression of the mRNA encoding for the MCP-1 protein, which stimulates the recruitment of monocytes into the arterial wall. Present data suggest that the influx of stimulated monocytes into the subendothelial space could affect redox-sensitive transcription factors and gene expression in the endothelium, thereby possibly leading to endothelial dysfunction
Effect of benzoyl peroxide on antioxidant status, NF-kappaB activity and interleukin-1alpha gene expression in human keratinocytes.
No full textBenzoyl peroxide (BP) is used as a topical treatment for acne. Besides its anti-bacterial activity, the exact molecular mechanisms underlying its mode of action are not fully understood. In the current study, the effects of BP on cell viability, antioxidant status and, IL-1 and IL-8 gene expression were investigated in HaCaT keratinocytes. Keratinocytes incubated for 24 h with BP exhibited a dose-dependent cytotoxicity at concentrations above 250 microM. Furthermore, in the presence of 300 microM BP about 50% of the cellular vitamin E was depleted within the first 30 min. The intracellular ratio of oxidized to reduced glutathione (GSSG/GSH) was increased significantly starting 6 h after BP treatments indicating that BP reacts rapidly with targets in the cell membrane and more slowly with those in the cytosol. NF-kappaB transactivation was not significantly affected by BP. However, BP treatment of HaCaT keratinocytes resulted in a dose-dependent increase in IL-1alpha gene expression whereas no changes in IL-8 mRNA levels were observed. These results demonstrate that BP induces an inflammatory reaction mediated by oxidative stress by a pathway independent of the redox-sensitive transcription factor NF-kappaB
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
Activity of monomeric, dimeric, and trimeric flavonoids on NO production, TNF-alpha secretion, and NF-kappaB-dependent gene expression in RAW 264.7 macrophages.
No full textFlavonoids are potent antioxidants and have been associated with lowering the risk of cardiovascular diseases. In this study, the effect of flavonoids (monomers, dimers and a trimer) as well as French maritime pine bark extract, Pycnogenol, on NO production, tumor necrosis factor-alpha (TNF-alpha) secretion and nuclear factor (NF)-kappaB activity was compared. Monomers and dimers repressed NO production, TNF-alpha secretion and NF-kappaB-dependent gene expression induced by interferon gamma, whereas the trimeric procyanidin C2 and Pycnogenol enhanced these parameters. In addition, in unstimulated RAW 264.7 macrophages, both procyanidin C2 and Pycnogenol increased TNF-alpha secretion in a concentration- and time-dependent manner. These results demonstrate that procyanidins act as modulators of the immune response in macrophages
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