1,720,960 research outputs found
Enhanced induction of plasma interferon after subcutaneous administration in rabbits of poly ICLC with albumin
No full textIntravenous administration of poly ICLC in rabbits yields very high plasma interferon (IFN) levels; dosages from 250 to 1000 micrograms/kg body weight are very toxic. Subcutaneous administration of poly ICLC together with a high concentration of human serum albumin potentiates the inducer activity in comparison to poly ICLC in saline. Finally, a dosage of 50 micrograms of poly ICLC in 12% serum albumin is more effective as an IFN inducer than other dosages
Renal filtration, absorption and catabolism of human alpha interferon
No full textThe renal handling of human interferon-alpha has been evaluated by using an isolated and perfused rabbit kidney. IFN-alpha disappears from plasma with a t1/2 of 81 min and the fractional turnover rate is 0.84%/min. About 47 molecules of IFN-alpha are filtrated with 100 molecules of creatinine but most of the IFN is absorbed by tubular cells. This is the first report showing that human IFN-alpha is filtrated by the kidney, largely absorbed, most probably catabolized within tubular epithelium and excreted in negligible amounts with the urine
Role of intracellular Ca2+ and calmodulin/MAP kinase kinase/extracellular signal-regulated protein kinase signalling pathway in the mitogenic and antimitogenic effect of nitric oxide in glia- and neurone-derived cell lines.
No full textTo elucidate the mechanism of cell growth regulation by nitric oxide (NO) and the role played in it by Ca2+, we studied the relationship among intracellular Ca2+ concentration ([Ca2+]i), mitogen-activated protein kinases [extracellular signal-regulated protein kinase (ERK)] and proliferation in cell lines exposed to different levels of NO. Data showed that NO released by low [(z)-1-[2-aminiethyl]-N-[2-ammonioethyl]amino]diazen-1-ium-1,2diolate (DETA/NO) concentrations (10 μM) determined a gradual, moderate elevation in [Ca2+]i (46.8 ± 7.2% over controls) which paralleled activation of ERK and potentiation of cell division. Functionally blocking Ca2+ or inhibiting calmodulin or MAP kinase kinase activities prevented ERK activation and antagonized the mitogenic effect of NO. Experimental conditions favouring Ca2+ entry into cells led to increased [Ca2+]i (189.5 ± 4.8%), ERK activation and cell division. NO potentiated the Ca2+ elevation (358 ± 16.8%) and ERK activation leading to expression of p21Cip1 and inhibition of cell proliferation. Furthermore, functionally blocking Ca2+ down-regulated ERK activation and reversed the antiproliferative effect of NO. Both the mitogenic and antimitogenic responses induced by NO were mimicked by a cGMP analogue whereas they were completely antagonized by selective cGMP inhibitors. These results demonstrate for the first time that regulation of cell proliferation by low NO levels is cGMP dependent and occurs via the Ca2+/calmodulin/MAP kinase kinase/ERK pathway. In this effect the amplitude of Ca2+ signalling determines the specificity of the proliferative response to NO possibly by modulating the strength of ERK activation. In contrast to the low level, the high levels (50–300 μM) of DETA/NO negatively regulated cell proliferation via a Ca2+-independent mechanism
Pharmacokinetics of human lymphoblastoid interferon in rabbits
No full textBy intravenous (bolus) administration of large amounts (29 Mega Units) of lymphoblastoid interferon into rabbits, it has been possible to detect circulating antiviral activity (0.02% of the dose) up to 18 hr post-injection and to determine for the first time the pharmacokinetic parameters. The slow component (elimination phase) has a half-life of 235 +/- 9 min. The total apparent volume of distribution is 2,564 +/- 1,497 ml which is far larger than the combined plasma-extracellular volumes. This suggests a IFN dilution due to its extensive binding to cell receptors. The clearance of 7.3 +/- 4.1 ml/min is an index of the rate of renal and cellular (internalization of the receptor-ligand complex) catabolism of IFN. Pharmacokinetic parameters are useful for devising an administration schedule of IFN as an antiproliferative agent but are not predictive of an immunological response if IFN is used as an immuno-adjuvant
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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