1,720,973 research outputs found
An intriguing link between human leukocyte antigen G, T-regulatory cells and neutrophil gelatinase-associated lipocalin in immune tolerance induction
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Potential advantages of acute kidney injury management by mesenchymal stem cells
No full textMesenchymal stem cells are currently considered as a promising tool for therapeutic application in acute kidney injury (AKI) management. AKI is characterized by acute tubular injury with rapid loss of renal function. After AKI, inflammation, oxidative stress and excessive deposition of extracellular matrix are the molecular events that ultimately cause the end-stage renal disease. Despite numerous improvement of supportive therapy, the mortality and morbidity among patients remain high. Therefore, exploring novel therapeutic options to treat AKI is mandatory. Numerous evidence in animal models has demonstrated the capability of mesenchymal stem cells (MSCs) to restore kidney function after induced kidney injury. After infusion, MSCs engraft in the injured tissue and release soluble factors and microvesicles that promote cell survival and tissue repairing. Indeed, the main mechanism of action of MSCs in tissue regeneration is the paracrine/endocrine secretion of bioactive molecules. MSCs can be isolated from several tissues, including bone marrow, adipose tissue, and blood cord; pre-treatment procedures to improve MSCs homing and their paracrine function have been also described. This review will focus on the application of cell therapy in AKI and it will summarize preclinical studies in animal models and clinical trials currently ongoing about the use of mesenchymal stem cells after AKI
Impact of blood source and component manufacturing on neurotrophin content and in vitro cell wound healing
No full textBackground: We evaluated neurotrophin (NF) levels and their impact on in vitro cell wound healing in eye drops from differently prepared blood sources (cord blood [CB], and peripheral blood [PB]) in the same donor, to avoid intrasubject biological variability. Materials and methods: Twenty healthy adult donor PB samples, and twenty CB samples acquired at the time of delivery were processed to obtain serum (S), platelet-rich plasma (PRP), platelet-poor plasma (PPP), and S retrieved from PRP after activation with Ca-gluconate (PRP-R). The levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), glial-derived neurotrophic factor (GDNF), fibroblast growth factor (FGF), and epidermal growth factor (EGF) were assessed with a Luminex xMAP (Luminex Corporation), and by using multikine kits from R&D system, and were statistically analysed in the eight different preparations. The impact of S, PRP, PPP, PRP-R from both sources on a cell line responding to NF supplementation (MIO-M1, UCL Institute of Ophthalmology, London, UK) was tested with a scratch wound assay, and analysed by IncuCyte S3 equipment. Results: All the preparations from CB showed higher NF levels, except for BDNF where no difference was found as compared to PB. PRP showed higher NF levels with respect to S, PPP and PRP-R in this decreasing order. Younger donors in PB contributed with higher NF levels. The scratch assay showed different cell migration results, with a complete wound closure only recorded with the supplementation of CB-S, and a progressive reduction by using PRP, PRP-R, and PPP from both sources. Discussion: Protocols of preparation and choice of blood source determine different NF levels in the final products. The therapeutic use of a natural neurotrophin pool from blood sources might have a clinical impact in several different settings. Efforts are needed to standardise the manufacturing and the product content in order to establish and modulate the posology of the final supplementation
Is chronic kidney disease-mineral and bone disorder associated with the presence of endothelial progenitor cells with a calcifying phenotype?
No full textBackground: Chronic kidney disease-mineral and bone disorder (CKD-MBD) has been implicated in vascular calcification pathogenesis. CKD-MBD results in alterations in the number and function of circulating endothelial progenitor cells (EPCs), physiological regulators of angiogenesis and vessel repair, commonly defined as proangiogenic progenitor cells (PACs) by the antigen pattern CD34+CD133+KDR+CD45-and putative EPCs by the pattern CD34+CD133-KDR+CD45-. These cells might acquire a calcifying phenotype in CKD-MBD, expressing mineralization biomarkers. We investigated the expression of vitamin D receptor (VDR) and osteocalcin (OC) on EPCs of healthy individuals and haemodialysis patients, and their possible associations with circulating biomarkers of inflammation and vascular calcification. Methods: We compared EPC counts, expressing VDR or OC, in 23 healthy subjects versus 53 haemodialysis patients, 17 of them without vitamin D receptor agonist (VDRA) therapy and 35 treated with calcitriol (n = 17) or paricalcitol (n = 18). The correlations with serum levels of inflammatory and calcification indexes were also analysed. Results: All subsets expressing VDR or OC were significantly higher in haemodialysis patients compared with healthy controls, but PACs were increased only in VDRA treatment subgroup, while putative EPCs showed a similar rise also in untreated patients. In VDRA-untreated patients, OC+ PACs correlated positively with calcium levels, while in VDRA-treated patients, VDR+ PACs correlated positively with interleukin 6 levels, and OC+ PACs correlated positively 25-hydroxyvitamin D levels. Conclusions: Our data suggest that in CKD-MBD, EPCs undergo an endothelial-to-procalcific shift, representing a risk factor for vascular calcification. A link between mineral disorders and vitamin D replacement therapy emerged, with potential adverse effects for CKD patients
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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