1,720,962 research outputs found
Effect of oxidative stress on canonical/non-canonical WNT pathways in colon cancer cell lines
No full textThe importance of aberrant regulation of Wnt/β-Catenin signaling in the pathogenesis and colorectal cancer progression has long been recognised. Recent studies have shown that reactive oxygen species (ROS) production activates the Wnt/β-Catenin pathways, but the mechanisms involved remain unclear. Excess in ROS production is linked to chronic inflammation and promotes DNA damages and repair systems.
We aim to evaluate the relationship among oxidative stress response and canonical/non-canonical Wnt pathways in colorectal cancer cell line models with different Wnt signaling behaviour
Helicobacter Pylori ATCC 43629 outer membrane vesicles (OMVs): a vehicle for extracellular DNA (eDNA) transport.
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
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
Selective insulin resistance affecting nitric oxide release but not plasminogen activator inhibitor-1 synthesis in fibroblasts from insulin-resistant individuals
No full textOBJECTIVE:
Insulin activates several processes potentially dangerous for the arterial wall and hyperinsulinemia might be atherogenic. However, other insulin effects are protective for the vessel wall and thus anti-atherogenic. Aim of this study was to investigate whether insulin effects on potentially pro-atherogenic and anti-atherogenic processes were differently affected in cells from insulin-resistant individuals.
METHODS AND RESULTS:
We determined insulin effect on nitric oxide (NO) production and plasminogen activator inhibitor (PAI)-1 synthesis in 12 fibroblast strains obtained from skin biopsy samples of 6 insulin-sensitive (IS) (clamp M >7 mg/kg body weight per minute) and 6 insulin-resistant (IR) (clamp M <5 mg/kg body weight per minute) healthy volunteers. Insulin effects on NO release and Akt phosphorylation were significantly impaired in fibroblasts from IR as compared with IS individuals. Conversely, there was not any difference between IR and IS strains in insulin ability to increase PAI-1 antigen levels and, after 24-hour insulin incubation, PAI-1 mRNA increase in IR strains was only slightly less than in IS strains. Insulin ability to induce MAPK activation was also comparable in IR and IS cells.
CONCLUSIONS:
We conclude that in cells from IR individuals, insulin action on anti-atherogenic processes, such as NO release, is impaired, whereas the hormone ability to stimulate atherogenic processes, such as PAI-1 release, is preserved
Oxidative Stress Induces WNT Canonical/Non-Canonical Pathway Modulation in Colon Cancer Cells with APC or beta-Catenin Mutation
No full textBackground-aim. It has long been recognised that the aberrant regulation of WNT/β-Catenin signaling is involved in the pathogenesis of colorectal cancer. Chronic inflammation predisposes to colon carcinogenesis by increased reactive oxygen species (ROS) levels and can impair the Wingless/It (WNT)/β-Catenin. This pathway is essential for gut morphogenesis, tissue homeostasis and self-renewal and its aberrant activation may drive the colorectal cancer (CRC), but the molecular mechanisms involved in CRC progression are still undefined. To evaluate the molecular relationship among oxidative stress and canonical/non-canonical Wnt pathways, we analyzed the response to ROS exposure in CRC cell lines with different Wnt signaling behaviour.
Methods. HCT116 (β-Catenin) and SW480 (APC) cells were exposed to Hydrogen Peroxide (H2O2) as oxidizing agent for different times and concentrations (from 50 μM to 10 mM). We assayed cell viability/mitochondria activity by MTS and cell cycle by FACS. Gene expression was evaluated by SYBR Green qRT-PCR in cells under acute stress conditions [2 mM and 10 mM] for 15’and 30’. Protein expression was analysed by IHC. Statistical analysis was performed by T-test (p value<0.05).
Results. MTS revealed rates of cell inhibition and growth at different H2O2 concentrations. FACS analysis of cell cycle showed time dependent changes: after H2O2 [2mM] treatment at 15’, SW480 increased in G1 and G2 and decreased in S, whereas HCT116 increased in G1 and slightly reduced in G2; after 30’, SW480 enhanced in G1 and S, and reduced in G2 while HCT116 diminished in G1 and increased in S/G2. In SW480 cells, acute stress induced by lower H2O2 concentration [2mM] up-regulated gene expression of canonical LRP6 and LEF1, and non-canonical ROR2 and JUN/AP1 molecules. While in HCT116 the same H2O2 concentration [2mM] reduced ROR2 and LRP6 expression of WNT co-receptor and differently affected the WNT transcription factors, upregulating LEF1 (canonical) and downregulating JUN/AP1 (non-canonical). As regard APC, it showed a behaviour dependent on time and concentration of H2O2 treatment. IHC protein expression analysis showed that H2O2 treatment induced FZD6 in HCT116 cytoplasm and E-cadherin in SW480 cytoplasm, while beta-catenin increased in both cell lines. Intriguingly oxidative stress induced a de novo APC expression in cytoplasm of both cell lines.
Conclusions. In CRC cells with mutations in APC or B-catenin, oxidative stress differently affects the WNT pathways at gene and protein expression levels. Our results could unravel an APC central role in driving and maintaining tumorigenesis and a novel scenario for innovative CRC therapeutic approaches
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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