1,720,966 research outputs found
Forme molecolari della γ-glutammiltransferasi: Caratteristiche e biogenesi
No full textFour GGT fractions (b-, m-, s- and f-GGT) have been described in plasma. The aim of this study was to characterize their molecular nature in human plasma and bile. Plasma was obtained from healthy volunteers and primary bile was collected from patients undergoing liver transplant. For each GGT fraction we determined MW, density, sedimentation conditions in centrifugation assays, and the sensitivity to detergent [deoxycholic acid (DOC)] and protease (papain). A partial purification of b-GGT for immunogold analysis was obtained by ultracentrifugation. Plasma b-GGT showed a MW of 2000 kDa and a density between 1.063-1.210 g/mL. Treatment with 1% DOC converted b-GGT into s-GGT fraction, while b-GGT was not sensible to papain treatment. Plasma m-GGT and s-GGT showed a MW of 1000 and 200 kDa, and their densities were between 1.006-1.063 g/mL and 1.063-1.210 g/mL, respectively. Both fractions were unaffected by DOC treatment, while GGT activity was completely recovered in f-GGT peak after their incubation with papain. Plasma f-GGT showed a MW of 70 kDa and a density >1.21 g/mL. In human hepatic bile we identified two peaks showing the same characteristics of plasma b- and f-GGT fractions. Collected data showed that b-GGT is constituted by membrane microvesicles both in bile and plasma, as confirmed by immunogold; m-GGT and s-GGT might be constituted by bile-acid micelles, while f-GGT represents the free-soluble form of the enzyme. The understanding of the nature and properties of plasma GGT fractions may allow a better clinical utilization of GGT as a clinical biomarker
HepG2 Spheroids as in Vitro Model to Study the Release of Gamma-glutamyltransferase Fractions
No full textThe β-adrenergic system as a possible new target for pharmacologic treatment of neovascular retinal diseases
No full textRetinal neovascular pathologies, such as diabetic retinopathy, retinopathy of prematurity (ROP) and agerelated
macular degeneration, may be treated with intravitreal injections of drugs targeting vascular
endothelial growth factor (VEGF), the main inducer of neoangiogenesis; however further improvements
and alternative strategies are needed. In the last few years, an intense research activity has focused on
the b-adrenergic system. The results indicate that, in different experimental models, a decrease of the badrenergic
function may result either in reduction or in exacerbation of the vascular changes, thus
suggesting possible dual effects of b-adrenoreceptor (b-AR) modulation depending on the experimental
setting. In in vivo models of proliferative retinopathies, most of the data point to a strong inhibitory role
against vascular changes exerted by the blockade of specific b-ARs. In particular, the b2-AR seems to be
the mostly involved in these responses, and the b1-/b2-AR blocker propranolol results highly effective in
inhibiting both the increase of VEGF expression caused by a hypoxic insult and the consequent neovascular
response. These observations have prompted clinical trials in preterm infants with ROP, where
oral administrations of propranolol produced positive results in terms of efficacy, although safety
problems were also reported. In addition, the possibility of using topical propranolol administrations in
the form of eye drops opens new potential routes of drug administration in humans. A further point that
should be considered is that there are data demonstrating significant antiapoptotic effects exerted by b-
ARs, therefore if b-AR blockers were used to inhibit aberrant neovascularization, there may be a burden
to pay in terms of impaired neuronal viability
Fractions of Gamma-Glutamyltransferase in healthy individuals, alcohol addicts and patients with hepatic disease
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
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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