1,720,957 research outputs found
Increased proatherogenic monocyte-platelet cross-talk in monocyte subpopulations of patients with stable coronary artery disease
No full textBackgroundMonocytes and platelets are important cellular mediators of atherosclerosis. Human monocytes can be divided into CD14(++)CD16(-), CD14(++)CD16(+) and CD14(+)CD16(++) cells, which differ in their functional properties. The aim of this study was to examine monocyte subset distribution, monocyte-platelet aggregate (MPA) formation and expression of CCR5, the receptor of the platelet-derived chemokine CCL5, and to determine whether these parameters are altered in individuals with coronary atherosclerosis. MethodsPeripheral blood cells from 64 healthy blood donors (HBDs) and 60 patients with stable coronary artery disease (CAD) were stained with antibodies against CD14, CD16, CD42b and CCR5 and analysed by flow cytometry. Circulating CCL5 levels were determined using an enzyme-linked immunosorbent assay. ResultsIn patients with CAD, the relative proportion of the CD14(++)CD16(-) monocyte subset was elevated (P<0.05) and of the CD14(+)CD16(++) subset was reduced (P<0.001) compared with the HBD group. Furthermore, MPA formation significantly increased in patients with CAD in all three monocyte subsets. In both study groups, the majority of CCR5(+) cells was detected in CD14(++)CD16(+) monocytes (P<0.001 versus CD14(++)CD16(-) and CD14(+)CD16(++)), although the CCR5(+) monocyte number was reduced in patients with CAD (CD14(++)CD16(-)/CD14(+)CD16(++), P<0.001; CD14(++)CD16(+), P<0.05) compared with the HBD group, particularly in those who were not taking statins. Ex vivo incubation of monocytes from HBDs with plasma from patients with CAD also decreased CCR5(+) expression (P<0.05 versus plasma from HBDs). Serum CCL5 levels were similar in both groups. ConclusionsThe increased monocyte-platelet cross-talk in patients with CAD might have contributed to atherosclerosis progression. The decreased CCR5(+) monocyte numbers in patients with CAD could have resulted from CCR5(+) cell recruitment into atherosclerotic lesions or CCR5 downregulation in response to circulating factors
Atheroprotective Kruppel-like factor 4 is downregulated in monocyte subsets of patients with coronary artery disease
No full textCirculating Endothelial Cells Expressing the Angiogenic Transcription Factor Kruppel-Like Factor 4 are Decreased in Patients with Coronary Artery Disease
No full textObjective: The zinc finger transcription factor KLF4 is known to control diverse EC functions. Methods: The functional role of KLF4 for angiogenesis and its association with CAD was examined in HUVECs and human CECs. Results: In two different angiogenesis assays, siRNA-mediated KLF4 downregulation impaired HUVEC sprouting and network formation. Conversely, KLF4 overexpression increased HUVEC sprouting and network formation. Similar findings were observed after incubation of HUVECs with CdM from KLF4 cDNA-transfected cells, suggesting a role of paracrine factors for mediating angiogenic KLF4 effects. In this regard, VEGF expression was increased in KLF4-overexpressing HUVECs, whereas its expression was reduced in HUVECs transfected with KLF4 siRNA. To examine the relevance of our in vitro findings for human endothelial dysfunction, we analyzed the expression of KLF4 in CECs of patients with stable CAD. Flow cytometry analyses revealed decreased numbers of KLF4-positive CECs in peripheral blood from CAD patients compared to healthy controls. Conclusions: Our findings suggest that KLF4 may represent a potential biomarker for EC dysfunction. In the future, (therapeutic) modulation of KLF4 may be useful in regulating EC function during vascular disease processes
In Vitro and In Vivo Effects of Human Monocytes and their Subsets on New Vessel Formation
No full textObjectiveHuman monocytes can be divided into CD16(-) monocytes and CD16(+) monocytes. Studies in mice suggested differential effects of monocyte subsets during new vessel formation. MethodsThe functional role of human monocyte subsets in neovascularization processes was investigated. For in vivo experiments, nude mice underwent unilateral hindlimb ischemia surgery before being injected with either total monocytes, CD16(-) monocytes or CD16(+) monocytes isolated from healthy individuals. ResultsIn vitro, cytokine array analysis demonstrated that monocytes release numerous angiogenic cytokines, some of which were differentially expressed in monocyte subsets. Sprout length was enhanced in EC spheroids being cultured in conditioned medium obtained from total monocytes and, to a lesser extent, also in supernatants of CD16(-) monocytes. Laser Doppler perfusion imaging up to day 28 after surgery revealed a trend toward improved revascularization in mice treated with monocytes, but no significant differences between monocyte subsets. Histological analyses four weeks after surgery showed an increased arteriole size in mice having received CD16(+) monocytes, whereas the number of capillaries did not significantly differ between groups. ConclusionsOur findings suggest additive and differential effects of monocyte subsets during neovascularization processes, possibly due to an altered secretion of angiogenic factors and their paracrine capacity to stimulate new vessel formation
Differential expression of proatherogenic cell markers on monocyte subpopulations of patients with stable coronary artery disease
No full textMonocytes and platelets are important cellular mediators of atherosclerosis. Human monocytes can be divided into CD14++CD16− , CD14++CD16+ and CD14+CD16++ cells, which differ in their functional properties. The aim of this thesis was to examine monocyte subset distribution, monocyte-platelet aggregate (MPA) formation, expression of CCR5, the receptor of the platelet-derived chemokine CCL5, of OPN receptor CD44, monocyte migration chemokine, of KLF4, an atheroprotective protein, and other soluble chemokines, to determine whether these parameters are altered in individuals with coronary atherosclerosis.2017-04-0
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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