1,721,032 research outputs found
Exacerbations and time spent outdoors in chronic obstructive pulmonary disease
No full textPatients with chronic obstructive pulmonary disease have a progressive reduction in activity, although its time scale and the contribution of exacerbations are unknown. A rolling cohort of 147 patients (101 male; mean age, 88.5 years; and forced expiratory volume in 1 second as percent predicted, 38.4%) were monitored for a median of 1,044 days (interquartile range, 685 to 1,779) over an 8-year period starting in March 1996. Patients recorded any increase in daily respiratory symptoms and time spent outside their home. They completed the St. George's Respiratory Questionnaire yearly. They experienced 1,465 exacerbations and time outdoors decreased by -0.16 hours/day per year (p < 0.001). This decline was faster in frequent exacerbators (p = 0.011). Before exacerbation, the patients stayed indoors all day for 2.1 days/week (on any day 34.1% were at home), but for 5 weeks postexacerbation they spent 2.5 days/week at home (p < 0.001) (44.4% remaining at home at onset; p = 0.021). St. George's total, activity, and impact scores were independently associated with time outdoors (p < 0.005), but not with symptom score. In conclusion, time spent outside the home declines over time and acutely at exacerbation. Patients with frequent exacerbations are more likely to become housebound and need targeting in rehabilitation programs.<br/
Airway bacterial load and FEV1 decline in patients with chronic obstructive pulmonary disease
No full textChronic obstructive pulmonary disease (COPD) is characterized by an accelerated decline in lung function and progressive airway inflammation. Bacteria have been isolated from the lower airway of stable COPD patients, and airway inflammation has been related to bacterial load and type. The relationship between bacterial colonization, airway inflammation, and lung function decline remains uncertain. We studied 30 patients with COPD, mean (SD) FEV1 0.947 (0.329), 34.8% (13.6%) predicted, for 12 months. Sputum collected at recruitment and the end of the study was analyzed for cytokines and for quantitative bacteriology. The decline in FEV1 was 57.6 (137.6) ml year-1. Bacterial growth was identified in all subjects, with an initial count of 107.47(0.91) cfu ml-1 rising to 107.93(0.81) cfu ml-1 at the end of the study (p = 0.019). FEV1 decline was related to this increase in airway bacterial load (r = 0.59, p = 0.001). FEV1 decline was greater in subjects who exhibited a change in the colonizing bacterial type compared with those with persistence of a single bacterial species over the study period (p = 0.017). Higher sputum interleukin (IL-8) was associated with greater declines in FEV1 (p = 0.03). Rising airway bacterial load and species changes are associated with greater airway inflammation and accelerated decline in FEV1. Bacterial colonization in COPD is an important factor in disease progression.<br/
Respiratory syncytial virus, airway inflammation, and FEV1 decline in patients with chronic obstructive pulmonary disease
No full textBACKGROUND: Respiratory syncytial virus (RSV) is increasingly recognized as an important pathogen in adults with cardiopulmonary disease. It has been associated with acute exacerbations of chronic obstructive pulmonary disease (COPD); however, it has also been detected in the lower airway in the stable state, but the consequences of RSV in stable disease have not previously been determined. We therefore studied the consequences of RSV persistence in adults with COPD and its effect on airway inflammation and lung function decline. METHODS: A total of 241 sputum samples from 74 patients with COPD (FEV(1)% predicted, 39.2%; interquartile range, 29.6-57.8%) were collected quarterly in the stable state over 2 yr. RSV was detected by polymerase chain reaction (PCR), quantitative microbiology was performed, and inflammatory cytokines were quantified by ELISA. RESULTS: RSV RNA was detected in 32.8% of sputum samples. Patients in whom RSV was more frequently detected (> 50% of samples RSV PCR-positive, n=18) had higher airway inflammation and faster FEV(1) decline over the study (101.4 ml/yr [95% confidence interval, 57.1-145.8]) compared with those with less frequent detection of RSV (n=56; 51.2 ml/yr [31.7-70.8]; p=0.01). The observed relationship between RSV detection and accelerated lung function decline was independent of smoking status, exacerbation frequency, and lower airway bacterial load. CONCLUSIONs: Persistent RSV detection in patients with COPD is associated with airway inflammation and accelerated decline in FEV(1). Chronic RSV infection may be a novel therapeutic target to alter the natural history of COPD.<br/
Early therapy improves outcomes of exacerbations of chronic obstructive pulmonary disease
No full textTreatment of chronic obstructive pulmonary disease (COPD) exacerbations improves outcomes; however, responses to treatment are variable, and patients with COPD often delay presentation or fail to seek therapy. The impact on exacerbation outcomes, hospitalization, and health status of delaying or failing to seek treatment is poorly understood. We studied between 1996 and 2002 a cohort of 128 patients with COPD, mean (SD) FEV(1) of 1.07 (0.43) L. Patients recorded respiratory symptoms daily and reported exacerbations to the outpatient-based study team or to their primary care physician; 1,099 exacerbations were recorded by the patients, of which 658 were reported to a physician. The time between exacerbation onset and treatment was a median (interquartile range) of 3.69 (2.0-5.57) days, and the exacerbation recovery time was 10.7 (7.0-14.0) days. Earlier treatment was associated with a faster recovery (regression coefficient 0.42 days/day delay) (confidence interval, 0.19-0.65; p < 0.001). Patients who reported a higher proportion of exacerbations for treatment had better health-related quality of life than those patients with more untreated exacerbations (rho = -0.22, p = 0.018). Failure to report exacerbations was associated with an increased risk of emergency hospitalization (rho = 0.21, p = 0.04). Patient recognition of exacerbation symptoms and prompt treatment improves exacerbation recovery, reduces risks of hospitalization, and is associated with a better health-related quality of life.<br/
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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