1,721,032 research outputs found
Neuroanatomy of the bipolar brain: from brain structure to treatment
Full text linkIn this thesis, I summarized results from researches done during my PhD course, organizing them in a brief introduction and five chapters. Specifically, the first chapter of this work is dedicated to the progress made during the past years in neuroimaging technologies and techniques, with a focus on structural Magnetic Resonance Imaging techniques and their employment into the neuropsychiatric research.
The following three chapters are dedicated to the three studies, all developed though a specific research topic and directed to the understanding of the neural basis of Bipolar Disorder and its clinical implications
F2-Isoprostanes as markers of oxidative stress and mediators of CCl4-induced liver fibrosis
No full textINTRODUCTION: F2-isoprostanes are considered as the most reliable markers of OS in vivo and mediators of some important biological effects, such as the vasoconstriction of kidney glomerular arterioles. It is known that hepatic fibrosis induced by CCl4 may be linked to oxidative stress (OS). In previous studies, we demonstrated the role of isoprostanes as possible mediators of CCl4-induced hepatic fibrosis. Plasma levels of isoprostanes were found to be elevated in rat chronically treated with CCl4 and correlated with hepatic collagen content. We also demonstrated that in vitro isoprostanes induced a marked increase in DNA and collagen synthesis in cultured hepatic stellate cells (HSC), in the concentration range found in the in vivo studies (1-10 nM). It has been suggested that isoprostanes act through the activation of receptors analogous to those for tromboxane A2 (TxA2r). Thus, the possible occurrence of TxA2r on HSC was investigated. Binding studies with [3H]SQ29548 (a specific antagonist of TxA2r) and competition binding experiments with I-BOP (a specific agonist of TxA2r) demonstrated the existence of TxA2r in HSC and the involvement of TxA2r in Iso-evoked responses. We then examined which signal transduction pathways are set into motion by isoprostanes to exert their fibrogenic effects. METHODS: HSC were isolated from the rat liver and treated with 8-epi-PGE2the most represented isomer). Ins(1,4,5)P3 (IP3) and cAMP levels were determined by commercial kits. Activation of mitogen-activated protein kinases (MAPK) and cyclin 1 was assessed by Western blotting. Cell proliferation and collagen production were assessed by measuring the incorporation of 3H-thymidine and 3H-proline, respectively. RESULTS: 8-epi-PGE2 increased 4 times IP3 and affected cAMP production. The expression of cyclin D1, a molecule involved in cell proliferation, is also increased. Furthermore, 8-epi-PGE2 activated two classes of MAPK: extracellular signal-regulated kinase (ERK) and p38, which have been shown to influence cell proliferation and collagen gene expression. CONCLUSION: On the basis of these data, it is possible to hypothesize that one of the pathways activated by 8-epi-PGF2a is that of Gq/PKC. The binding of isoprostanes to TxA2r could stimulate downstream MAPK activation, via PKC. In particular, p38 is known to increase in HSC collagen production, while ERK is able to increase cyclin D1 expression and then cell proliferation. Thus, fibrogenic effects of isoprostanes in HSC are mediated through TxA2r binding by specific activation of these transduction pathways
Signalling pathways involved in isoprostane-induced fibrogenic effects in hepatic stellate cells
No full textINTRODUCTION: We have previously shown that the levels of plasma F2-Isoprostanes (F2-Iso) are maintained elevated in the model of chronic CCl4 intoxication leading to fibrosis and cirrhosis, and correlated to the increased hepatic collagen. F2-Iso can also potentially mediate some of the adverse effects of oxidant injury. We demonstrated that in hepatic stellate cells (HSC) some fibrogenic events (such as cell proliferation and collagen synthesis) are induced by F2-Iso through the activation of receptors analogous to those for tromboxane A2 (TP receptor), but how isoprostanes act to initiate these events remains unclear. METHODS: HSC were isolated from rat liver and treated with 8-epi-PGF2the most represented isomer). Inositol-3-phosphate (IP3) and cAMP levels were determined by commercial kits. Activation of MAPK and cyclin D1 was assessed by Western blotting. Cell proliferation and collagen production were determined by measuring the incorporation of 3H-thymidine and 3H-proline, respectively. RESULTS: A transient increase of cAMP was observed. 8-epi-PGF2also increased IP3 levels and activated ERK and p38 MAPK which have been shown to influence cell proliferation and collagen gene expression, as well as cyclin D1 expression. Collagen synthesis and cell proliferation induced by 8-epi-PGF2 were completely reversed by PD98059, a specific inhibitor of ERK activation. CONCLUSIONS: The data obtained suggest that one of the pathways activated by 8-epi-PGF2 is that of Gq/PKC. The binding of isoprostanes to TP receptor in HSC could stimulate downstream MAPK activation, leading to an increased collagen production. Furthermore the ability of ERK to increase cyclin D1 expression can stimulate cell proliferation
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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