1,721,010 research outputs found
The progestin ORG2058 but not retinoic acid stimulates BRCA1 mRNA expression in MCF-7 human breast cancer cells.
No full textBRCA1 has been characterized as one of the major breast cancer susceptibility genes. Although no BRCA1 mutations have been reported in sporadic breast cancer, altered levels of BRCA1 are found in non hereditary breast malignant lesions. Therefore, BRCA1 is potentially playing a key role in the genesis of breast cancer. In this study, we explored the effects of estradiol and two differentiating agents, the progestin ORG2058 and retinoic acid, on BRCA1 mRNA expression in human estrogen and progesterone receptor positive MCF-7 cells. Using RNAse protection assay, we have demonstrated that ORG2058 induces a major (50 times) stimulation of BRCA1 mRNA expression. The maximum induction effect was obtained at the pharmacological dose of 100 nM and after 48 h of treatment. While estradiol generated an expected increase of BRCA1 mRNA, retinoic acid did not produce any effects. Our results demonstrate for the first time that BRCA1 is specifically up-regulated by a progestin, a steroid known to induce the differentiation of epithelial mammary cells. The absence of retinoic acid effect suggests that a specific progesterone-dependent pathway, could control BRCA1 expression
Ancient nucleic acid in human organic remains from S. Domenico Maggiore Abbey mummies in Naples, Italy (XV-XVI centuries)
No full text
Down regulation of NM23.H1, NM23.H2 and c-myc genes during differentiation induced by 1,25 dihydroxyvitamin D3.
No full textLactoferrin expression in human breast cancer.
No full textWe analyzed lactoferrin expression in 78 samples from patients with sporadic breast cancer and found 31/78 negative for mRNA expression. Similar results were obtained by immuno-histochemical localization of the lactoferrin protein. We did not find relationship between lactoferrin expression and clinical parameters. We investigated for the absent lactoferrin expression in some cases of breast cancer. In 68 of the samples analyzed, we found an inverse correlation between estrogen receptor expression and lactoferrin expression (P < 0,0001), thus indicating that regulation by the estrogen receptor is not the main element responsible for the expression of lactoferrin in breast cancer. Analysis of methylation of the lactoferrin genomic DNA extracted from the same patients revealed that the degree of methylation does not explain the observed absence of lactoferrin. The 937 bp lactoferrin promoter was investigated for possible mutations. By single-strand conformation polymorphism analysis one polymorphic site was found and characterized
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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