1,721,025 research outputs found
le infezioni come comorbidità della BPCO
No full textLe infezioni sia acute che croniche si manifestano con maggiore frequenza nei pazienti affetti con BPCO rispetto alla popolazione generale. In questo articolo vengono revisionati i meccanismi patogenetici, i quadri clinici e le strategia teraputich
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
Pharmacological prevention of COPD exacerbations
No full textExacerbations of COPD are characterized by changes in the patient’s baseline dyspnoea, cough, and/or sputum that are beyond normal day-to-day variations, that are acute in onset, and that may warrant a change in regular medication. The frequency and severity of exacerbations increase with disease severity and are associated with poorer quality of life and health outcomes, with a greater burden on health care, accelerated decline of lung function, and increased risk of death. For all these reasons, exacerbations are a major target of prevention and treatment in patients with COPD.While exacerbations are increasingly used as primary outcome or secondary pre-specified outcome in clinical trials in COPD, major limitations of the studies on COPD exacerbations are that the definition is based on symptoms and not on objective measurements. Furthermore, the definition varies between studies, and often comorbidities are not adequately taken into account. Worsening of daily respiratory symptoms, particularly dyspnoea, could be associated with respiratory events, such as pneumonia, or non respiratory events, such as heart failure, thromboembolisms, and renal failure, among others. Long-acting bronchodilators alone or in combination with inhaled glucocorticosteroids are the most effective treatment for reducing the number and severity of COPD exacerbations—even though caution is required in interpreting the results of some trials. Suissa and coworkers, in their recent papers on methodological issues, suggest that the results of major randomized controlled clinical trials that evaluate the effect of treatment on COPD exacerbations might be biased by the facts that many patients enrolled in the studies are already receiving inhaled therapy before randomization, and that the results could be influenced by withdrawal from the ongoing effective therapy. Another bias might be that patients included in the trials are often not followed after discontinuation of treatment; considering the different rates of withdrawal between treatments and the different causes of withdrawal, this may severely affect the interpretation of the data. Statistical methods are also critical. A statistical approach that does not weight for the length of the follow-up (unweighted approach), and for the within- and between-subject variability of exacerbations, may lead to false-positive results. In particular, this bias applies to all but two trials examining the effect of inhaled glucocorticosteroids on exacerbations, causing the authors of those studies to conclude that the positive effect of inhaled glucocorticosteroids on exacerbations is not supported by solid evidence. With these limitations, however, randomised controlled trials are and will remain the fundamental tools for evaluating the benefit of COPD treatment, and the data collected so far, albeit with the potential biases, are the only evidence available to support treatment recommendations.In this chapter we review the various classes of medications commonly used in treating COPD. We focus on the most effective medications for preventing exacerbations, such as inhaled long-acting bronchodilators alone or in combination with inhaled glucocorticosteroids. Also, considering their importance in the management of COPD, we briefly discuss the effects of smoking cessation and vaccinations on COPD exacerbations. We do not discuss the effects of treatment of exacerbations on subsequent exacerbations—obviously an important clinical aspect. In fact, short-term therapy with oral glucocorticosteroids after hospitalization for a COPD exacerbation reduces the likelihood of readmission for another exacerbation
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
New therapeutic indications for Cys-LT1 antagonists: chronic obstructive pulmonary disease.
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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
Endogenous blood maximal interferon-gamma production may predict response to interferon-gamma 1beta treatment in patients with idiopathic pulmonary fibrosis.
No full textBACKGROUND:Idiopathic pulmonary fibrosis (IPF) is an untreatable lung disorder with a mean survival of 3 years after diagnosis. Treatment with interferon-gamma (IFN-gamma) 1beta has been reported to significantly improve lung function and arterial oxygen saturation in a first randomized controlled trial; unexpectedly, these findings have not been confirmed in a subsequent large placebo-controlled randomized study. Another larger placebo-controlled randomized trial has been stopped because data analyzed at interim analysis excluded the possibility that treatment with IFN-gamma 1beta would cause a significant reduction in the risk of death.METHODS:Seven Italian male patients diagnosed with IPF were treated with IFN-gamma 1beta (200 microg/die subcutaneously three times a week), accordingly to the indications of the Italian Drug Agency. Based on available studies the response to treatment was pre-defined as changes in either lung function (FVC and DLCO) or oxygen arterial saturation. All patients consented to provide a peripheral blood sample for endogenous IFN-gamma production measurement with the ELISpot assay before treatment and 6 months thereafter.RESULTS:Four of 7 patients improved or stabilized their lung function after 6 months treatment. Using the ELISpot assay to quantify the maximal production of endogenous IFN-gamma on peripheral blood samples, these 4 patients had a significantly higher endogenous IFN-gamma production before therapy, as compared to the 3 patients who deteriorated (91.3 +/- 49.6 vs. 277.8 +/- 34.2 spot forming cells, p = 0.023). No significant differences were observed after 6 months of treatment.DISCUSSION:These preliminary results suggest that some IPF patients might benefit from treatment with IFN-gamma 1beta and may help to interpret the results of large randomized trials, suggesting that individual susceptibility could determine clinical response to treatment
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