1,721,003 research outputs found
Amniotic membrane reduces bile duct ligation-induced liver fibrosis
No full textRecently, stem/progenitor cell transplantation has been proposed as potential treatment for chronic liver disorders as an alternative to organ/hepatocyte transplantation. In this study, based on the fact that amniotic membrane (AM) has long been applied in clinic due to its anti-inflammatory and anti-scarring properties and that AM-derived cells display multipotent differentiation potential and immunomodulatory features, we investigated the potential application of human AM as an innovative therapeutic approach.
We evaluated the effects of hAM on biliary-type liver fibrosis induced in rats through bile duct ligation (BDL). A fragment of hAM was applied onto the liver surface after BDL and the rats were euthanised after 2, 4 and 6 weeks. The severity of liver fibrosis was assessed both semi-quantitatively by the Knodell scoring system and quantitatively, by digital image analysis, evaluating liver areas occupied by the ductular reaction (CK 19-positive cells), activated myofibroblasts (alpha-SMA-positive cells) and collagen deposition (Masson's staining).
hAM-treated rats displayed significantly lower liver fibrosis with respect to control rats. Indeed, in contrast with BDL rats which showed a progression of fibrosis to cirrhosis from week 4 to week 6, fibrosis in BDL+hAM rats was confined at the portal/periportal area, with collagen deposition at about 50% of levels observed in control rats. Concomitantly, AM application slowed progression of the ductular reaction and significantly reduced the area occupied by myofibroblasts.
These findings suggest that human AM patching might counteract fibrosis progression in BDL-injured livers and could represent a new strategy to limit hepatic damage associated with fibrotic degeneratio
In vitro immunomodulatory activity of conditioned medium from horse amniotic derived multipotent progenitor cells
No full textWe recently demonstrated that heterologous transplantation of horse amniotic-derived cells (AMCs) can be useful for cell therapy applications in tendon diseases. We hypothesized that AMCs may promote tendon repair via paracrine-acting molecules and to test this hypothesis we examined the immuno-modulatory characteristics of AMCs and of its conditioned medium (AMCs-CM) in vitro. To produce AMCs-CM, fresh AMCs at passage three were cultured for 5 days. Supernatants were lyophilized and stored at 4°C until use. Control (non-CM) was generated in the same way but without cells culturing. Lymphocyte proliferation was induced by stimulating peripheral blood mononuclear cells (PBMC) by phytohemagglutinin at the concentration of 2 lg/ml. To evaluate the effect of AMCs-CM, 50 or 100 ll/well of this supernatant or non-CM were added to activated PBMC. Effects of AMCs were studied either by cell-cell contact or by transwell system keeping a constant number of PBMC (2*105) and decreasing number of AMCs, to obtain ratios of PBMC : AMCs of 1 : 1, 1 : 0.5, 1 : 0.25, 1 : 0.125. Our results demonstrated that AMCs are capable of inhibiting PBMC proliferation in a dose-dependent manner, either in cell-cell contact or in transwell system, reaching to the 1 : 1 ratio an inhibition of 90% (p < 0.05). This finding suggests that soluble factors are implicated, and this hypothesis is supported by PBMC inhibition with the AMCs-CM that could represent a novel therapeutic cell-free product in regenerative medicine
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
In vitro immunomodulatory activity of conditioned medium obtained from amnion-derived horse progenitor cells and its first clinical application in horse tendon injuries
No full textWe recently demonstrated that heterologous transplantation of horse amniotic membrane-derived mesenchymal cells (AMCs) is useful for cell therapy applications in tendon diseases (Lange-Consiglio et al., 2012, 2013). Whether MSCs differentiate into tenocytes, supply immunomodulatory and trophic factors or if a combination of the two mechanisms occurs, is still debated. To test this hypothesis, we examined the immunomodulatory characteristics of AMCs and of their conditioned medium (AMCs-CM) in vitro, and studied the therapeutic effect of AMCs-CM in horse tendon injuries in vivo.
To produce AMCs-CM, AMCs at passage 3 were cultured for 5 days. Supernatants were lyophilized and stored at 4°C until use. Control (non-CM) was generated in the same way but without cells culturing. Lymphocyte proliferation was induced by stimulating peripheral blood mononuclear cells (PBMC) by phytohemagglutinin at the concentration of 2 μg/ml. To evaluate the effect of AMCs-CM, 50 or 100 μl/well of this supernatant or no-CM were added to activated PBMC. Effects of AMCs were studied either by cell-cell contact or by transwell system maintaining constant the number of PBMC (2*105) and decreasing the number of AMCs, to obtain ratios of PBMC:AMCs of 1:1, 1:0.5, 1:0.25, 1:0.125.
Sterile CM was intralesionally injected under ultrasonographic guidance in spontaneously damaged tendons of 13 private sport horses. Patients were clinically and ultrasonographically monitored monthly. Success criteria was return to former athletic function and absence of relapses.
Results demonstrated that AMCs are capable of inhibiting PBMC proliferation in a dose-dependent manner, either in cell-cell contact or in transwell system reaching a 90% (P≤0.05) decrease of PBMC proliferation at a ratio of 1:1. The same effect was also observed for the AMCs-CM but not for the control media. In vivo, intralesional procedures were well tolerated and a marked reduction in swelling and tendon cross sectional area were noticed. A treatment related neovascularization was Power Doppler imaged, in the affected area, in the early healing phase but not at later recovery stage. An obvious improvement in lesional ecogenicity and architecture was clearly noticeable just after 30 days. Two years after CM injection 84% of horses showed no relapses.
Our findings suggest that soluble factors are implicated in inhibiting PBMC proliferation and in tendon regenerative process that may initiate an anti-inflammatory and angiogenic response leading to tendon regenerative process. CM should be considered a safe, novel biologic cell-free therapeutic agent in regenerative medicine.
1. Lange Consiglio et al. Characterization and potential applications of progenitor-like cells isolated from horse amniotic membrane. J Tis Eng Reg Med 2012; 6: 622. 2. Lange Consiglio et al. Investigating the efficacy of amnion-derived compared with bone marrow-derived mesenchymal stromal cells in equine tendon and ligament injuries. Cytotherapy epub 2013
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