1,720,971 research outputs found
Presence of Phosphatidylserine Synthesizing Enzymes in Triton Insoluble Floating Fractions from Cerebrocortical Plasma Membranes
No full textMammals synthesize phosphatidylserine (PS), a binding PKC molecule, by exchanging the nitrogen base of phosphatidylethanolamine or phosphatidylcholine with free serine. Serine base exchange enzyme (SBEE) was found in Triton insoluble floating fractions (TIFFs) from rat cerebellum which contained PKC. Consequently, SBEE might modulate PS levels in the PKC binding area (Buratta et al., J Neurochem 103:942-951, 2007). In the present study, we determined whether SBEE and PKC were localised in rat cerebral cortex TIFFs (cx-TIFFs) and in rat cerebrocortical plasma membrane-TIFFs (PM-TIFFs) which are more directly involved in signal transduction than intracellular membranes. Cx-and PM-TIFFs expressed SBEE activity and contained PKC. SBEE used ethanolamine as free exchanging base which may modulate PS level in the PKC binding area, transforming PS into PE and vice versa. The slight decrease in [(14)C]serine incorporation in the presence of choline indicated the existence of a SBEE isoform which may play a peculiar role in this brain are
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Evaluating the risk of phospholipidosis using a new multidisciplinary pipeline approach
No full textPhospholipidosis (PLD) is an undesirable potential side-effect of drugs, and cationic amphiphilic drugs (CADs) represent the main class of PLD inducers. A CADs toxicophore has been recently proposed, although the CADs definition is far from being trivial. In this work we derive a three-dimensional CADs toxicophore (here named PLD-phore) using a molecular interaction field approach, and test its suitability to discriminate between PLD inducers and non-inducers in a virtual screening approach. Ten commercially available compounds predicted to be PLD inducers and non-inducers based on their similarity to the PLD-phore were experimentally tested for PLD induction using two cell-based in vitro assays (fluorescent lipid uptake, activity of secreted lysosomal β-hexosaminidase). When a positive effect was observed, the PLD induction was also confirmed by transmission electron microscopy. Two exceptions to the general statement about CADs and PLD induction were detected and discussed, and for one compound the cell-based in-vitro assays lead to different outcome
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
A role for the autophagy regulator Transcription Factor EB in amiodarone-induced phospholipidosis
No full textThe antiarrhythmic agent amiodarone, a cationic amphiphilic drug, is known to induce phospholipidosis, i.e. the accumulation of phospholipids within lysosomal structures to give multi-lamellar inclusion bodies. Despite the concerns raised about phospholipidosis in the recent years, the molecular mechanisms underlying amiodarone- or other cationic amphiphilic drug-induced phospholipidosis are still under investigation. Here we demonstrated that amiodarone doses able to induce phospholiposis according to NBD-PC uptake assay (1-12μM, 24h) activates Transcription Factor EB (TFEB), a pivotal regulator of the autophagic pathway, in human HepG2 cells. Further evidences confirmed the effect of amiodarone on the autophagic-lysosomal system in HepG2 and BEAS-2B cells: lysosomal β-hexosaminidase isoenzymes secretion, transcriptional up-regulation of the lysosomal β-hexosaminidase α-subunit, alteration of cathepsin B, D and L intracellular maturation in a cell- and protease-specific manner. Autophagy activation was also demonstrated by increased conversion of LC3-I into LC3-II and reduced phosphorylation of the mTORC1 target S6 kinase. Besides, we provided evidence that TFEB over-expression prevents amiodarone-induced phospholipid accumulation, suggesting that this transcription factor could be a possible target to develop strategies for phospholipidosis attenuation
Exosome-based strategies for Diagnosis and Therapy
No full textExosomes are small extracellular vesicles (30-120 nm) of endosomal origin, which are gaining the attention of the scientific community. Originally considered only a waste disposal system, they are now emerging as another class of signal mediators. Exosomes are secreted by any cell type and retrieved in every body fluid, such as blood, urine, saliva and amniotic liquid. Remarkably, their biochemical content includes not only lipids and proteins, but also nucleic acids, mainly miRNA and mRNA, with a few reports also indicating the presence of genomic and mitochondrial DNA. Their properties have stimulated extensive research to exploit them as a source of biomarkers for the diagnosis and the follow-up of several pathologies. Furthermore, exosomes are relatively robust and stable, so they appear attractive as gene and drug delivery vehicles. They have also revealed immunomodulatory and regenerative properties, which are encouraging their application for therapeutic purposes. Several issues remain to be addressed: exosome isolation is still time consuming and unsatisfactorily reproducible, making it difficult to compare results among laboratories, improve our knowledge of their physiological function and correlate their features with pathological outcomes. Nevertheless, the number of patents trying to address these problems is growing exponentially and many novelties will reach the scientific community in the next few years. - See more at: http://www.eurekaselect.com/132726/article#sthash.rReGlCtk.dpu
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