1,721,115 research outputs found
There is a choice for immunosuppressive drug nephrotoxingcity: Is it time to change?
No full textThe central issue in organ transplantation remains suppression
of allograft rejection. Thus, development of
immunosuppressive drugs is the key to successful allograft
function. New immunosuppressive drugs were
introduced on the basis of their ability to reduce the
incidence of acute rejection and to demonstrate shortterm
outcomes at least equivalent to those achieved
with the use of established immunosuppressive therapy.
Although short-term renal allograft survival has
improved since the introduction of calcineurin inhibitors
(CNIs), long-term renal allograft survival remains
a major concern, with chronic allograft nephropathy
(CAN) being the principal cause of renal allograft loss
after the first year. CAN has traditionally been viewed
as the result of repeated low-grade immune responses
directed against allogeneic tissue, but recent evidence
indicates that nonimmunological or alloantigen-independent
factors also contribute to its pathogenesis.
CNI nephrotoxicity occurs soon after initiation of therapy,
is more clearly dose-dependent. This scenario
presents a clear need for new strategies that produce
adequate immunosuppression to prevent acute rejection
and simultaneously reduce adverse effects associated
with CNI-related therapies. To obtain significant
long-term improvement in renal allograft outcomes, it
may be necessary to adopt new immunosuppressive
regimens that rely less on CNIs
Older donors and older recipients in kidney transplantation
No full textOver the last 2 decades, while kidney transplantation
became the therapy of choice for end-stage renal
disease, the increasing gap between the limited
supply of cadaveric donors and the rising demand for
kidneys led to the consideration of alternative strategies
to provide more organs for transplant. The significant
increase of mean donor age suggested the use
of kidneys from older donors. In addition, an increasing
number of donors with significant comorbidities
(e.g., hypertension and diabetes) or deceased due to
stroke have been used since the early 1990s, leading
to the definition of the fuzzy and disputed concept of
“marginal” donors. Such organs are eligible for organ
donation but, because of extreme age and other clinical
characteristics, are expected to produce allografts
at risk for diminished posttransplant function. Thus,
the challenge is now to improve the graft outcome
gap between patients receiving grafts from “marginal”
and “optimal” donors. This implies appropriate
transplantation strategies during all transplant phases,
including reduction of cold ischemia time, recipient
selection, adaptation of immunosuppressive drug
regimens, increase in nephron mass by dual kidney
transplantation and improvement in the graft selection
process using histological criteria. This review summarizes
the current definition of a marginal donor and
provides some suggestions for clinical management
of these particular kidney transplants. We believe that
in this particular transplanted population, an effective
balance should be ensured between maintaining graft
survival, reducing the impact of immunosuppressive
toxicity and maximizing patient quality of life through
the reduced incidence of cardiovascular disease and
malignancies
Immunosuppressive drugs and renal transplantation
No full textAlthough the use of new immunosuppressive drugs, and their combination have drastically reduced the incidence of acute rejections, the graft survival is unchanged in the last ten years. The immunosuppressive drugs can be divided in four classes, according to their different site of molecular action: proliferative signal inhibitors, amplification signal inhibitors; STATs inhibitors, DNA synthesis inhibitors. Steroids act on immune system through several mechanisms. Azathioprine is an anti-metabolite that inhibits de-novo synthesis of purins, acting on S-phase of cellular cycle. Mycophenolate-Mofetil (MMF) is also an anti-metabolite, purine synthesis inhibitor that, differently from azathioprine, acts specifically on IMPDH (Inositolmonophosphate-dehydrogenasis) through a non-competitive mechanism. Calcineurin inhibitors (cyclosporin and tacrolimus) act on amplification of intracellular signal. The most important therapeutic side-effect of calcineurin inhibitors is the nephrotoxicity. Other inhibitor agents of the amplification signal are monoclonal antibodies anti-á chain of IL-2 (CD25). Another drug used in the last years, is sirolimus (SRL) or rapamycine, an immunosuppressive agent that act, through the inhibition of T lymphocyte activation
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
Proteinuria in the prognosis of IgA nephropathy. Aucella F, Netti GS, Piemontese M, Cincione IR, Infante B, Gesualdo L.
No full textIgA Nephropathy (IgAN) is the most common lesion causing primary glomerulonephritis in the world. The main clinical predictors of progression are: elevated blood pressure, high histological score and proteinuria. Although elevated serum creatinine concentration at diagnosis, increased excretion of cytochines, age at onset, obesity and genetic factors may all influence clinical outcome, it is quite clear that proteinuria is the hallmark of renal damage in IgAN. Patients with IgAN and little or no proteinuria (3 g/day. The product of duration (years) and urinary protein excretion (g/day) at the time of renal biopsy is more significantly correlated with progression. So, this so called proteinuria index may be a useful predictor for glomerular and interstitial histopathological changes and the fate of renal function in IgAN. The progression of IgAN may be slowed by antihypertensive and antiproteinuric therapy, such as angiotensin converting enzyme inhibitors and/or angiotensin II receptor blockers, that can minimize secondary glomerular injury. Proteinuria has been shown to be an adverse prognostic factor in IgAN, with a strong relationship between proteinuria and prognosis and established importance of remission. Consequently, targeting proteinuria may be a valid surrogate for individualized kidney protective therapy
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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