1,721,001 research outputs found
p38α, the β-catenin chromatin associated kinase, as promising target in colorectal cancer stem cells for personalized therapy
Full text linkColorectal cancer (CRC) is the third most frequent malignancy, but the second cause of death for tumor in the western population. Only 14% of patients with advanced and metastatic disease survive five years from diagnosis. Recently, it has been shown that tumor relapse and chemoresistance depend on a small population of cells, called cancer stem cells (CSCs). Current evidence indicates that the Wnt cascade is the main driver in controlling CSC fate; the key player in this pathway is β-catenin, a cytoplasmic protein whose stability is regulated by the so-called “destruction complex”. During carcinogenesis, the increasing amount of β-catenin resulting from APC inactivation translocates into the nucleus, causing the transcriptional activation of several mitogenic genes, including c-Myc. c-Myc is one of the most important factors involved in CRC initiation and progression; indeed, it functions as a link connecting malignancy with stemness. During colorectal carcinogenesis, c-Myc is maintained upregulated through β-catenin-mediated transcriptional activation and ERK-mediated post-translational stabilization. Our data showed that p38α, a kinase involved in CRC metabolism and survival, contributes to both mechanisms. Previous reports in other tissues provided evidence that Wnt3a can activate p38, and the p38 pathway feeds into the canonical Wnt/β-catenin pathway at least at the level of GSK3β. Our findings also highlighted that CRC cells and colorectal cancer stem cells (CRC-SCs) have higher levels of activated p38 than their normal counterparts, and experiments using kinase-specific inhibitors revealed that these cells are “addicted” to p38 activity. Importantly, we found that p38α co-immunoprecipitates with β-catenin in both normal and cancer cells; however, these proteins are confined to the cytoplasm in colonocytes, while they significantly occupy discrete nuclear regions in CRC cells, CRC-SCs, and in vivo models. These data were further corroborated by the inhibitory effect of p38α blockade on several β-catenin-responsive genes (i.e. c-Myc, cyclin D1/2, survivin, and others). This functional interaction was further characterized by chromatin immunoprecipitation experiments, which demonstrated that p38α is a chromatin-associated β-catenin kinase required for the transcriptional induction of several Wnt target genes, including c-Myc. Additionally, we demonstrated that p38α, like ERK, stabilizes c-Myc protein levels by preventing its ubiquitination. The finding that the phenotypes arising after APC loss in the intestine are fully dependent on c-Myc target gene expression suggests that c-Myc inhibition may be a good target for chemoprevention in CRC. These considerations underline the relevance of molecular profiling and preclinical investigation in order to achieve more efficient and accurate therapies. Indeed, our study identifies p38α as a promising therapeutic target acting directly on c-Myc and CRC-SCs, which are thought to be responsible for tumor proliferation, metastatic dissemination, and chemoresistance
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
"Disturbi di Lateralizzazione ed Emicrania in età evolutiva" (Laterality Problems in Childhood MIgraine)
No full text"Test di Soppressione al Desametazone: risposte in pazienti con cefalea in età evolutiva". (Dexamethazone Suppression Test:preliminary reports in Daily Chronic Headache of Adolescents)
No full textAppropriate 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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