1,721,052 research outputs found
Evaluation of chemopreventive activity of spinach extracts of plant grown in normal and hypoxic condition
No full textConsumption of fresh fruits and vegetables in the human diet is important to maintain a good health status and to prevent chronic diseases. It is well known that plant derived food is a powerful source of chemopreventive molecules such as antioxidants (polyphenols, catechins, etc..). Stress response represents a powerful stimulus for plants to produce metabolites with high value for human health. However, to date, this approach has not been extensively used yet, since too much mechanistic information is still lacking.
To find responses to this, we have investigated Spinach (Spinacia oleracea L., Chenopodiaceae) grown in normal or in hypoxic condition. Spinach leaves, commonly present in the human diet both raw and cooked, are a concentrate of bio-active compounds, molecules with a great medical value but rarely diffused in the Plant Kingdom such as phytoecdysteroids. The aqueous extracts of lyophilized Spinach leaves have been administered to tumoral colon cell line HT-29 to evaluate their chemoprotective effects. Cell viability assay (MTS) have been used to assess the antiproliferative activity while Comet Assay have been used to consider the cito-genotoxity of the extracts. The extracts of plants grown in hypoxic condition exert an antiproliferative activity greater than those grown in normal conditions. None of the extracts exerted any genotoxic activity when tested alone. To better understand the way of action of the antiproliferative activity we found, we tested the antioxidant activity of the extracts by the comet assay, after a co-treatment with a known oxidizing agent as H2O2, and the induction of apoptosis in HT-29 cell line by TUNEL assay.
Unexpectedly, the spinach extracts did not shown any antioxidants activity in vitro, meanwhile they seemed to induce apoptosis.
The analyses of the chemical composition of the extracts are ongoing, they could permit us to identify the chemical mixture present in the different extracts and which compound is responsible for the increased antiproliferative activity shown by the plants grown in hypoxia.
What we found does not confirm what reported by Moser that showed an antioxidant activity of spinach in in vivo studies. Taking into account these observations, we plan to simulate the digestion of the extracts to understand if the antioxidant activity could be due to a chemical modification of the original mixture
Human myeloma cells upregulate RANKL and downregulate OPG in bone environment: evidence of OPG/RANKL imbalance in multiple myeloma patients
No full textLinear FDEM subsoil data inversion in Banach spaces
Full text linkThe applicative motivation of this paper is the reconstruction of some electromagnetic features of the earth superficial layer by measurements taken above the ground. We resort to frequency domain electromagnetic data inversion through a well-known linear integral model by considering three different collocation methods to approximate the solution of the continuous problem as a linear combination of linearly independent functions. The discretization leads to a strongly ill-conditioned linear system. To overcome this difficulty, an iterative regularization method based on Landweber iterations in Banach spaces is applied to reconstruct solutions which present discontinuities or have a low degree of smoothness. This kind of solutions are common in many imaging applications. Several numerical experiments show the good performance of the algorithm in comparison to other regularization techniques
Morphological features of rat gastric mucosa after acute and chronic treatment with amtolmetin guacyl: comparison with non-selective and COX-2 selective NSAIDs
No full textBackground/Aims: The compound amtolmetin guacyl (AMG) has been characterized in both animal and human studies as a novel non-selective non-steroidal anti-inflammatory drug (NSAID) endowed with lower ulcerogenicity in comparison with traditional NSAIDs due to a unique mechanism of action, namely the increase in endogenous production of gastric nitric oxide. Methods: Conscious rats were treated either acutely (4 h) or chronically (3 and 14 days) with intragastric AMG (50 and 150 mg/kg), the non-selective NSAID tolmetin (TOL, 30 and 100 mg/kg) or the COX-2-selective NSAID celecoxib (CXIB, 20 and 60 mg/kg). Macroscopically visible and histologic lesions were evaluated. The ultrastructure of mucosal microvasculature was assessed. Results: (1) TOL and CXIB caused quantitatively greater endothelial damage and inflammatory cell infiltration than that induced by AMG; (2) AMG and CXIB, unlike TOL, did not cause epithelial damage after acute or chronic treatment, and (3) gastric lesions induced by TOL underwent adaptation during chronic treatment. Conclusion: Endothelial cell damage in the gastric microvasculature is an early event following both non-selective and COX-2-selective inhibitors. The low gastric mucosa
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
Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality
Full text linkThe chondroitin sulfate proteoglycan 4 (CSPG4) gene encodes a transmembrane proteoglycan (PG) constituting the largest and most structurally complex macromolecule of the human surfaceome. Its transcript shows an extensive evolutionary conservation and, due to the elaborated intracellular processing of the translated protein, it generates an array of glycoforms with the potential to exert variant-specific functions. CSPG4-mediated molecular events are articulated through the interaction with more than 40 putative ligands and the concurrent involvement of the ectodomain and cytoplasmic tail. Alternating inside-out and outside-in signal transductions may thereby be elicited through a tight functional connection of the PG with the cytoskeleton and its regulators. The potential of CSPG4 to influence both types of signaling mechanisms is also asserted by its lateral mobility along the plasma membrane and its intersection with microdomain-restricted internalization and endocytic trafficking. Owing to the multitude of molecular interplays that CSPG4 may engage, and thanks to a differential phosphorylation of its intracellular domain accounted by crosstalking signaling pathways, the PG stands out for its unique capability to affect numerous cellular phenomena, including those purporting pathologic conditions. We discuss here the progresses made in advancing our understanding about the structural-functional bases for the ability of CSPG4 to widely impact on cell behavior, such as to highlight how its multivalency may be exploited to interfere with disease progression.Tamburini, E., Dallatomasina, A., Quartararo, J., Cortelazzi, B., Mangieri, D., Lazzaretti, M., Perris, R. Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality
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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