1,720,975 research outputs found
Milk-derived bioactive peptides exhibit antioxidant activity through the Keap1-Nrf2 signaling pathway
Full text linkBioactive peptides are relevant nutritional factors that exhibit many functions including antioxidant, anti-hypertensive, anticancer and antimicrobial properties. In this paper, four synthetic peptides ARHPHPHLSFM (A-11-M), AVPYPQR (A-7-R), NPYVPR (N-6-R) and KVLPVPEK (K-8-K) with sequences present in milk proteinswere examined for their antioxidant properties. The compounds show moderate free radical scavenging activityin the ABTS and crocin assays (A-7-R and N-6-R) and lipid peroxidation inhibition in Caco-2 cells (N-6-R and K-8-K). All peptides, in particular K-8-K, activate the Keap1-Nrf2 system by allowing the translocation of the tran-scription factor Nrf2 from the cytosol to nucleus. This activation triggers the overexpression of the antioxidantenzymes Trx1, TrxR1, GR, NQO1 and SOD1. Furthermore, molecular modeling shows that K-8-K is able to hinderthe interaction of Nrf2 with Keap1. The reported results show that the antioxidant action in cells of thesebioactive peptides is mostly due to the activation of Keap1-Nrf2 signaling pathwa
Thioredoxin reductase: A target for gold compounds acting as potential anticancer drugs
No full textThe thioredoxin system plays a key role in regulating the overall intracellular redox balance. It basically
comprises the small redox protein thioredoxin (Trx), nicotinamide adenine dinucleotide phosphate, in
its reduced form (NADPH), and thioredoxin reductase (TrxR), a large homodimeric selenzoenzyme controlling
the redox state of thioredoxin. Details of the thioredoxin system are provided herein, particular
emphasis being given to the protein chemistry of thioredoxin reductases. Several lines of evidence point
out today that the thioredoxin system represents an effective “druggable” target for the development
of new anticancer agents. Accordingly, a number of established anticancer agents were retrospectively
found to be potent inhibitors of thioredoxin reductases and to induce severe oxidative stress. During the
last decade a variety of gold compounds, either gold(I) or gold(III), were reported to manifest outstanding
antitumor properties, forming a promising class of experimental anticancer agents. In turn, recent
studies have revealed that several cytotoxic gold compounds, either gold(I) or gold(III), are potent TrxR
inhibitors. Details of their mechanism of selenoenzyme inhibition are currently under investigation, in
our laboratory, and some newresults will be anticipated here; notably, preferential gold targeting of active
site selenolate could be experimentally supported. Based on the numerous experimental evidences now
available, both at the molecular and cellular level,we propose that the relevant cytotoxic actions produced
by gold compounds are mainly the result of potent inhibition of thioredoxin reductase; the alterations of mitochondrial functions, elicited by profound TrxR inhibition, would eventually lead to cell apoptosis.
A general and unitary framework is thus offered to interpret the mode of action of cytotoxic gold compounds,
according to which they should be primarily considered as antimitochondrial drugs. The peculiar
properties of gold compounds highlighted in this review might be further exploited for the obtainment
of newer and selective anticancer agents
Gold complexes inhibit mitochondrial thioredoxin reductase: consequences on mitochondrial functions
No full textThioredoxin reductase, an emerging target for anticancer metallodrugs. Enzyme inhibition by cytotoxic gold(III) compounds studied with combined mass spectrometry and biochemical assays
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
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