1,720,966 research outputs found
Analysis of the DNA contant distribution of micronuclei using flow sorting and fluorescent in situ hybridization with a centromeric DNA probe.
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A mixture of isothiocyanates induces cyclin B1- and p53-mediated cell-cycle arrest and apoptosis of human T lymphoblastoid cells
No full textAs with other candidate chemopreventive agents, most of our knowledge on the biological effects of isothiocyanates (the many sulfur-containing metabolites found in cruciferous vegetables) comes from studies of single natural or synthetic compounds. To investigate whether the biological/chemopreventive effects of administration of single isothiocyanates can differ from those of a mixture of isothiocyanates, we tested the effects of a mixture of four different isothiocyanates on cell-cycle progression and apoptosis in human T-leukemia Jurkat cells, and identified some of the molecular pathways triggered by the mixture. The mixture affected critical points of the cell-cycle via modulation of the expression of cyclin B1. Moreover, it induced apoptosis, mediated by an increase in p53 and bax (expression of bcl-2 was unaffected). Comparison of the data with those previously obtained with the single isothiocyanates under identical experimental conditions provides evidence that the quantitative effects of a single, specific isothiocyanate can be significantly different from those of an isothiocyanate mixture at realistic doses
In vitro anticancer activity of cyanidin-3-O-beta-glucopyranoside: effects on transformed and non-transformed T lymphocytes.
No full textBACKGROUND: Little is known regarding the potentially chemopreventive activity of cyanidin-3-O-beta-glucopyranoside (Cy-g), the main anthocyanin present in the juice of pigmented oranges, apart from its antioxidant activity. After excluding a potential genotoxicity of Cy-g, its ability to induce apoptosis on transformed and normal T cells was analysed. In order to delineate the events leading to apoptosis, the expression of different proteins, known to be involved in apoptosis, was also measured. MATERIALS AND METHODS: The evaluation of genotoxicity was performed by the micronucleus test. Flow cytometry was used for the analysis of apoptotic cells and proteins involved in the modulation of apoptosis. RESULTS: Cy-g was nongenotoxic. Moreover, it induced apoptosis in both cell systems, modulated by an increase of p53 and bax proteins. CONCLUSION: These interesting biological properties should encourage further studies into the chemopreventive potential of Cy-g. Nevertheless, its activity in normal T cells underlines the need for extensive toxicological investigation
In vitro antitumour activity of cyanidin-3-O-beta-glucopyranoside.
No full textBackground: Little is currently known regarding the cancer preventive potential of cyanidin-3-O-b-glucopyranoside (Cy-g) apart from its antioxidant activity. Methods: We tested Cy-g on Jurkat and HL-60 leukemia cell lines and, to help elucidate whether the effects of Cy-g are specific for cancer cells, also on normal T lymphocytes. Results: Cy-g-induced apoptosis on all three cell systems, and this indicated that Cy-g was not selective towards leukemia cells. Moreover, Cy-g caused HL-60 differentiation. The induction of apoptosis and cytodifferentiation involved different proteins, thus suggesting that Cy-g-induced apoptosis and cytodifferentiation are two distinct events. Conclusions: Although in vitro, our findings indicate that Cy-g possess some interesting biological properties that should encourage further investigation as regards its chemotherapeutic potential
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
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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