1,721,016 research outputs found
Glucocorticoids and the immune function in the human immunodeficiency virus infection: a study in hypercortisolemic and cortisol-resistant patients
No full textImmunological studies in human immunodeficiency virus (HIV)positive patients suggest that the disease progression is accompanied by a defective production of type 1 cytokines [interleukin-2 (IL-2) and IL-12], an increased production of type 2 cytokines (IL-4, IL-6, and IL-10), and an increased production of IgE. HIV infection is also associated with activation of the hypothalamo-pituitary-adrenal axis function and increased plasma and urinary cortisol concentrations. As cortisol is involved in the physiological regulation of cytekines, a study was conducted to examine cytokine patterns in two groups of hypercortisolemic patients, one with normal sensitivity to glucocorticoids and the other with glucocorticoid resistance. Ten HIV- infected patients with normal receptor affinity to glucocorticoids AIDS-C), 10 HIV-infected patients with low receptor affinity to glucocorticoids (AIDS- GR), and 20 healthy subjects were studied. Receptor characteristics of peripheral blood mononuclear cells were evaluated by [3H]dexamethasone binding. Serum cortisol and urinary free cortisol were measured by RIA. Serum ACTH and IgE were measured by immunoradiometric assay, and IL-2, IL-4, and IL-10 cytokines and interferon-γ were measured by enzyme-linked immunosorbent assay. AIDS-C patients showed low IL-2 and high IL-4, IL-10, and IgE concentrations: conversely, AIDS-GR patients showed high IL-2 and low IL-4 and IgE concentrations. Thus, in HIV infection, elevated cortisol levels suppress cell-mediated immunity and stimulate humoral immunity, whereas this response is not detected in cortisol-resistant patients. These findings indicate that cortisol and its receptors are critically involved in the regulation of immune function in HIV infection
Glucocorticoids and Th-1, Th-2 type cytokines in rheumatoid arthritis, osteoarthritis, asthma, atopic dermatitis and AIDS
No full textEndogenous or exogenous glucocorticoids play a key role in the control of the immune and inflammatory network. Regulation of the effects of the glucocorticoids depends on changes in therapeutic levels, but also, as recently discovered, on modifications of the binding characteristics of the glucocorticoid receptors of target cells. In rheumatoid arthritis (RA), chronic bronchial asthma, atopic dermatitis, in chondrocytes from osteoarthritic patients, and in advanced stages of HIV infection, there is a down-regulation of the glucocorticoid receptors. As a consequence, B cell immune proliferation is stimulated in RA, proteolysis is enhanced in osteoarthritis, the glucocorticoids' therapeutic effect is reduced in asthma and atopic dermatitis, and a chronic persistent increase of interferon α is seen in HIV. Finally, glucocorticoids are also capable of switching CD4 cells from a Th-1 to a Th-2 pattern. A decreased affinity of lymphocyte glucocorticoid receptors could hinder such a switch, with obvious clinical implications
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
Glucocorticoid resistance and the immune function in the immunodeficiency syndrome
No full textGlucocorticoids, the final product of HPA axis, and their receptors (GRs) on mononuclear cells are crucial mediators in the endocrine-immune interaction. An alteration in GRs involving a lower receptor affinity (K(d)) for glucocorticoids has been found in a group of advanced AIDS patients, who developed Addisonian symptoms (weakness, weight loss, hypotension, hyponatremia, and intense mucocutaneous melanosis) in spite of hypercortisolism and normal or slightly elevated values of ACTH (AIDS-GR). In these patients, data for the suppression test showed decreased cortisol and ACTH suppression in response to exogenous dexamethasone. The inhibitory effect of dexamethasone on radiolabeled-thymidine incorporation in mononuclear cells from these patients was also reduced. Monocytes of AIDS-GR patients had a receptor K(d) of 10.5 ± 4.2 nmol/l that was higher than that of other AIDS patients (AIDS-C) (2.9 ± 0.8 nmol/l) and normal subjects (2.0 ± 0.8 nmol/l: p < 0.01). Correlations were found between plasmatic IFN-alpha and receptor K(d) on monocytes of AIDS-GR (γ = 0.77). Poly (i)-poly (c)-induced IFN-alpha production by monocytes was inhibited by glucocorticoids in the AIDS-C group and controls (approx. 80% in both groups): The effect was reversed by the receptor antagonist RU-486. By contrast, glucocorticoid did not inhibit IFN-alpha production in AIDS-GR group. In conclusion, levels of plasmatic IFN-alpha, a cytokine with antiviral properties, may be increased several times, and dexamethasone fails to inhibit monocytes IFN-alpha production only in AIDS with cortisol resistance, a disturbance that confirms an important immunoregulatory role of glucocorticoids in HIV disease
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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