1,720,972 research outputs found
Nutrition-Based Modulation of Poly-ADP-Ribosylation and its possible role in Alzheimer’s disease
Full text linkAlzheimer’s Disease (AD) is the most common neurodegenerative disease and the main reason of dementia in the elderly. On the pathological point of view, it is characterized by extracellular aggregates of amyloid peptides and intracellular deposits of tau protein. These deposits affect neuron viability and functions by inducing (among other pathological pathways) oxidative stress and triggering mitochondrial dysfunction. It is now evident that free radicalinduced oxidative damage is strongly involved in the pathogenesis of AD.
Oxidative damage occurs early in disease pathogenesis and can exacerbate its progression. Post-mortem brain of individuals affected by AD, evidenced an extensive state of oxidative stress compared to healthy controls; markers of increased oxidation include, among others, DNA damage. DNA damage can induce the activity of the enzyme poly (ADP-ribose) polymerase 1 (PARP-1) that catalyze the reaction of poly (ADP-ribosylation). This post-translational modification modulates the functions of proteins involved in many physiological processes such as gene expression, maintenance of genomic stability and cell death. Therefore, inhibiting PARP-1 activity can represent a possible new strategy to reduce the impact of the oxidative stress in AD as well as in other neurodegenerative diseases. Here we discuss the role of nutrients in modulating PARP-1 activity and its perspective potential application
PARP-1 involvement in neurodegeneration: A focus on Alzheimer’s and Parkinson’s diseases
No full textDNA damage is the prime activator of the enzyme poly(ADP-ribose)polymerase1 (PARP-1) whose overactivation
has been proven to be associated with the pathogenesis of numerous central nervous system
disorders, such as ischemia, neuroinflammation, and neurodegenerative diseases. Under oxidative stress
conditions PARP-1 activity increases, leading to an accumulation of ADP-ribose polymers and NAD+ depletion,
that induces energy crisis and finally cell death. This review aims to explain the contribution of
PARP-1 in neurodegenerative diseases, focusing on Alzheimer’s and Parkinson’s disease, to stimulate
further studies on this issue and thereby engage a new perspective regarding the design of possible
therapeutic agents or the identification of biomarkers
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
Microglia, Abeta peptide and neuroinflammation: searching a connection with PARylated protein.
No full text
Role of S-adenosylmethionine in the modulation of oxidative stress-related neurodegeneration
No full textS-adenosyl-L-methionine (SAM) is the main biological methyl donor in transmethylation reactions,
consisting in the transferring of a methyl moiety to different substrates including DNA, proteins, lipids
and RNA. SAM level in the organism decreases with aging and restoring the original levels through
exogenous supplementation is an important tool for the improvement of many vital functions. Indeed,
SAM deficiency may contribute to the onset of several diseases, i.e. depression, liver diseases, osteoarthritis
and senile neurological disorders such as Alzheimer’s and Parkinson’s diseases. Recent evidences indicate
that SAM may have an involvement in oxidative stress, a process which typically involves an alteration of
cellular sulfur amino acids homeostasis. SAM is not only the principal methyl donor, but also a precursor
of glutathione, the major endogenous antioxidant, whose role in counteracting oxidative stress is well
known. In this review we will highlight the role of SAM not just as a methyl-donor but also as a regulator
of different metabolic pathways involved in the antioxidant response in brain related disorders
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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