1,721,008 research outputs found
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
Emerging Role of the Spleen in the Pharmacokinetics of Monoclonal Antibodies, Nanoparticles and Exosomes
No full textAfter being absorbed, drugs distribute in the body in part to reach target tissues, in part to be disposed in tissues where they do not exert clinically-relevant effects. Therapeutically-relevant effects are usually terminated by drug metabolism and/or elimination. The role that has been traditionally ascribed to the spleen in these fundamental pharmacokinetic processes was definitely marginal. However, due to its high blood flow and to the characteristics of its microcirculation, this organ would be expected to be significantly exposed to large, new generation drugs that can hardly penetrate in other tissues with tight endothelial barriers. In the present review, we examine the involvement of the spleen in the disposition of monoclonal antibodies, nanoparticles and exosomes and the possible implications for their therapeutic efficacy and toxicity. The data that we will review lead to the conclusion that a new role is emerging for the spleen in the pharmacokinetics of new generation drugs, hence suggesting that this small, neglected organ will certainly deserve stronger attention by pharmacologists in the future
Comparison of the everolimus concentrations measured in whole blood with everolimus QMS or sirolimus CMIA
No full textFew years ago, it was proposed that everolimus blood levels could be determined with the commercially available sirolimus chemiluminescence magnetic microparticle immunoassay (CMIA). More recently, a highly specific microsphere system (QMS) has been approved by FDA for therapeutic drug monitoring in humans. Aim of the present study was to compare the results of everolimus assay performed with everolimus QMS and with sirolimus CMIA. The two methods were compared with Passing-Bablok regression and Bland-Altman plot analysis. The Passing-Bablok regression analysis showed that although the results obtained with the two techniques were significantly correlated, CMIA-measured differed from QMS-measured everolimus concentrations by both a systematic and a proportional error. Specifically, at blood levels lower than 5 ng/mL CMIA were lower than QMS-measured everolimus concentrations. On the opposite, at everolimus blood concentrations higher than 10 ng/mL CMIA-estimated values became progressively higher than QMS-measured everolimus concentrations. The analysis of the Bland Altman plot showed a less than optimal agreement of the two tests (5.59% of the data point outside the ±1.96 SD interval). Moreover, the relationship between the difference between EveroQMSand EveroCMIAand their average was clearly concentration dependent with positive and negative values at concentration values lower and higher than 5 ng/mL respectively. In conclusion, our finding showed that the values of everolimus concentrations measured with sirolimus CMIA differ from those detected with the FDA-approved everolimus QMS further suggesting that sirolimus CMIA should not be used anymore for everolimus therapeutic drug monitoring
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
Pharmacokinetic interaction between levofloxacin and ciclosporin or tacrolimus in kidney transplant recipients: ciclosporin, tacrolimus and levofloxacin in renal transplantation
No full textBACKGROUND AND OBJECTIVE: Bacterial infections are common complications after organ transplantation. Fluoroquinolones are frequently used for treatment because of their broad spectrum of activity; but some of them, such as ciprofloxacin and norfloxacin, are reported to increase blood concentration of ciclosporin because they are metabolised by the liver through the same enzymatic pathway, the cytochrome P450 system. This study was performed to establish whether levofloxacin, a more recent fluoroquinolone that undergoes limited hepatic metabolism, interferes with metabolism and excretion of either ciclosporin microemulsion or tacrolimus. METHODS: Pharmacokinetic studies were carried out in two groups of renal transplant patients, on either ciclosporin or tacrolimus treatment, before and at the sixth day of treatment with levofloxacin. RESULTS: Levofloxacin significantly increased the mean area under the blood concentration-time curve (AUC) and the other pharmacokinetic parameters of ciclosporin and tacrolimus by about 25%. The interference of levofloxacin on the hepatic metabolism of these drugs was demonstrated by the concomitant decrease by 5% of polyclonal ciclosporin concentration, which is the expression of parent drug and its metabolites. Both before and during levofloxacin treatment we observed trough concentrations of monoclonal and polyclonal ciclosporin significantly lower in the evening (C(12)) than in the morning (C(0)); this observation suggests a circadian variation in the metabolism of this drug. However, no difference between C(0) and C(12) was observed with tacrolimus, confirming its more predictable bioavailability. CONCLUSION: Our data demonstrate that levofloxacin partially inhibits the metabolism of both ciclosporin microemulsion and tacrolimus, and therefore close therapeutic monitoring of these two drugs should be recommended during levofloxacin therapy
Circulating levels of sirtuin 4, a potential marker of oxidative metabolism, related to coronary artery disease in obese patients suffering from nafld, with normal or slightly increased liver enzymes
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