1,720,973 research outputs found
Riflessi di memoria kavafiana nella poesia turca
Full text linkThe paper describes elements of Cavafian poetics in the Turkish poetry of the 20th century, namely in the work of Ilhan Berk. Beyond the reception of Cavafy's poetry in Turkey, the aim of the study is to analyze the tangible and intangible impact that Cavafian poetical motifs and structures, especially concerning "memory", had on Berk
Modulation of A1 and A2B adenosine receptor activity: a new strategy to sensitise glioblastoma stem cells to chemotherapy.
No full textTherapies that target the signal transduction and biological characteristics of cancer stem cells (CSCs) are innovative strategies
that are used in combination with conventional chemotherapy and radiotherapy to effectively reduce the recurrence and
significantly improve the treatment of glioblastoma multiforme (GBM). The two main strategies that are currently being exploited to
eradicate CSCs are (a) chemotherapeutic regimens that specifically drive CSCs toward cell death and (b) those that promote the
differentiation of CSCs, thereby depleting the tumour reservoir. Extracellular purines, particularly adenosine triphosphate,
have been implicated in the regulation of CSC formation, but currently, no data on the role of adenosine and its receptors in the
biological processes of CSCs are available. In this study, we investigated the role of adenosine receptor (AR) subtypes in
the survival and differentiation of CSCs isolated from human GBM cells. Stimulation of A1AR and A2BAR had a prominent
anti-proliferative/pro-apoptotic effect on the CSCs. Notably, an A1AR agonist also promoted the differentiation of CSCs toward a
glial phenotype. The differential effects of the two AR agonists on the survival and/or differentiation of CSCs may be ascribed to
their distinct regulation of the kinetics of ERK/AKT phosphorylation and the expression of hypoxia-inducible factors. Most
importantly, the AR agonists sensitised CSCs to the genotoxic activity of temozolomide (TMZ) and prolonged its effects, most likely
through different mechanisms, are as follows: (i) by A2BAR potentiating the pro-apoptotic effects of TMZ and (ii) by A1AR driving
cells toward a differentiated phenotype that is more sensitive to TMZ. Taken together, the results of this study suggested that the
purinergic system is a novel target for a stem cell-oriented therapy that could reduce the recurrence of GBM and improve the
survival rate of GBM patients
TUMOR NECROSIS FACTOR ALPHA TRIGGERS OSTEOGENESIS THROUGH THE INVOVLVEMENT OF Gs-COUPLED RECEPTOR SIGNALS
Full text linkTumor Necrosis Factor alpha (TNF-α) plays a role in several chronic immune and inflammatory diseases, where inhibition of TNF has led to significant clinical improvement. Actually, this cytokine is involved in bone healing by affecting mesenchymal stem cell (MSC) behaviour in a dose- and time-dependent manner1,2. Indeed, in the early inflammatory phase after fracture, low doses of TNF-α are required to favour MSC migration, survival and differentiation, thus initiating bone repair. At high dose, in the chronic uncontrolled phase of inflammation, the same cytokine has destructive effects on bone and contribute to bone loss1,2.
As other soluble factors released in cell microenvironment, the cytokine modulates expression and functioning of different G protein coupled receptors (GPCRs) and of their regulatory proteins (GPCR regulated kinases, GRKs)3, thus dictating the final biological outcome of these receptor proteins in controlling bone anabolic processes.
Herein, we investigated the effects of TNF-α low doses on the expression and functional responsiveness of A2B adenosine receptor (A2B AR), a Gs-coupled puringergic receptor that controls mesenchymal stem cell (MSC) differentiation to osteoblasts4,5.
In our hands, TNF-α exerted a pro-differentiating action on MSCs, pushing towards an osteoblast phenotype, and without any effects on cell proliferation. The cytokine increased the A2B AR-mediated pro-osteogenic effects, through the A2B AR desensitization impairment mediated by GRK2 inhibition. These data i) support the anabolic effect of sub-massimal concentration of TNF-α in bone reparative processes and ii) demonstrate that the cytokine regulates GPCR responses by interfering with desensitization machinery and potentiating in turn the anabolic responses evoked by Gs-GPCRs. Overall these results indicated that manipulating MSC local environment by lregulates membrane receptors favouring bone remodelling
A1 AND A2B ADENOSINE RECEPTORS REGULATE GLIOBLASTOMA STEM CELL DIFFERENTIATION/SURVIVAL AND SENSITIZE CELLS TO CHEMOTHERAPY
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
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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