1,720,966 research outputs found
Tacrolimus, but not cyclosporine a, significantly increases expression of ICAM-1 and IFN-γ in the NOD mouse
No full text: We studied the alterations of cytokines and ICAM-1 expression in the NOD mouse pancreas produced by the administration of Cyclosporine A (CY) and Tacrolimus (TA), two widely used immunosuppressive drugs. Results evidenced differences in the effects of these two drugs. In fact, during treatment and after withdrawal, CY-treated animals remained euglycemic, showed good islet cell preservation and had low levels of Th1 and Th2 cytokines; ICAM-1 positivity within the islets was also found to be relatively low. On the other hand, TA-treated animals had infiltrated islets containing numerous dendritic cells, adhesion molecule overexpression, increased IFN-gamma and ICAM-1 mRNA transcripts, and interestingly, high levels of circulating ICAM-1. However, even these animals remained euglycemic. These findings lead to the thought that these drugs may exert their effects in very different ways. Moreover, in TA-treated animals, the presence of an islet infiltrate containing numerous dendritic cells coupled with maintenance of euglycemia is suggestive for the involvement of immunosurveillance mechanisms. J. Cell. Biochem. Suppl. 36: 107-116, 2001
The Harderian gland in autoimmune diabetes of the nonobese diabetic mouse
No full textInfiltration of the nonobese diabetic (NOD) mouse's Harderian gland (HG) was studied in 1-30-week-old animals. A mononuclear cell invasion of this gland is first seen in 8-week-old female mice (i.e., at a slightly later age than that for the onset of infiltration of pancreatic islets). Infiltrating elements are mainly located at the hilus of the gland or at one or two foci (periacinar infiltration) within the parenchyma. In the latter case, a few elements infiltrate the fibrous connective tissue surrounding the acini (one or more) without damaging them. The most severe histopathological lesion was observed in 16-week-old animals; at this time infiltration ranges from a still focal lesion to complete acinar destruction of the gland. Ultrastructural observations confirm that in several cases acinar cells are destroyed and the HG parenchyma is substituted with infiltrating elements, fibroblasts, and connective tissue. HG infiltration is comparable to the pancreatic inflammatory infiltration; the two processes are very similar, though insulitis starts slightly earlier than HG infiltration. Furthermore, as for insulitis and diabetes incidence, HG infiltration affects NOD males less than females. Moreover, immunocytochemistry has shown that T lymphocytes are the prevalent infiltrating element both in pancreatic islets and HGs. Further studies are required to understand the reasons for autoimmune destruction of this gland
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
PlGFMMP9-engineered iPS cells supported on a PEGfibrinogen hydrogel scaffold possess an enhanced capacity to repair damaged myocardium
No full textCell-based regenerative therapies are significantly improved by engineering allografts to express factors that increase vascularization and engraftment, such as placental growth factor (PlGF) and matrix metalloproteinase 9 (MMP9). Moreover, the seeding of therapeutic cells onto a suitable scaffold is of utmost importance for tissue regeneration. On these premises, we sought to assess the reparative potential of induced pluripotent stem (iPS) cells bioengineered to secrete PlGF or MMP9 and delivered to infarcted myocardium upon a poly(ethylene glycol)fibrinogen scaffold. When assessing optimal stiffness of the PEGfibrinogen (PF) scaffold, we found that the appearance of contracting cells after cardiogenic induction was accelerated on the support designed with an intermediate stiffness. Revascularization and hemodynamic parameters of infarcted mouse heart were significantly improved by injection into the infarct of this optimized PF scaffold seeded with both MiPS (iPS cells engineered to secrete MMP9) and PiPS (iPS cells engineered to secrete PlGF) cells as compared with nonengineered cells or PF alone. Importantly, allograft-derived cells and host myocardium were functionally integrated. Therefore, survival and integration of allografts in the ischemic heart can be significantly improved with the use of therapeutic cells bioengineered to secrete MMP9 and PlGF and encapsulated within an injectable PF hydrogel having an optimized stiffness. © 2014 Macmillan Publishers Limited
A collagen membrane-based engineered heart tissue improves cardiac function in ischemic rat hearts
No full textIn the relatively new field of cardiac tissue engineering, different biomaterials, methods and techniques have been tested for cardiac repair, but we are still far from the achievement of a valid model that can be tested for therapeutic goals. In this study, the authors examined the efficacy of newly preformed membranes based on collagen type I for the transplantation of cardiac cells. The membrane prototype, cross-linked with 1,4-butanediol diglycidyl ether (BDDGE) and fibronectin-enriched, gave rise to spontaneously beating heart cell constructs, 5-9 days after seeding with neonatal rat cardiac cells. This membrane was grafted, with and without beating cardiac cells, onto the infarcted area of rat models of heart failure. Seriate echocardiography, performed on rats before transplantation and at 4 and 8 weeks after transplantation, demonstrated that rats treated with collagen membranes previously seeded with beating cells showed an improvement in cardiac function after 8 weeks. These results suggest that this new type of collagen membrane can be used as vector for the transplantation of beating heart cells for the regeneration of the injured myocardium and hence represents an important potential tool for cardiac tissue repair technologies
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