1,720,980 research outputs found
The role of genetic factors in occupational asthma
No full textThis article explores the influence of genetic factors on the development of sensitisation and occupational asthma (OA). First, several types of studies aimed at examining the role of genes, as well as the role of gene-environment interactions in asthma, including the available data for OA specifically, were reviewed. Genetic approaches include linkage and allele-sharing analysis and segregation analysis. Secondly, deoxyribonucleic acid banking for epidemiological studies was focused upon, highlighting the factors to be considered in choosing the appropriate specimens for genotyping. OA, like asthma, is a multifactorial condition and, to date, no ideal genetic study has been described to examine complex gene-environment interactions. Most studies in OA have examined human leukocyte antigen-associated polymorphisms with some nonreproducible results. The search for genes in occupational asthma is still in progress, and much of the information obtained has been based on small sample sizes, using different strategies for the recruitment of subjects. The best methodological approach still needs to be determined and the results of genetic identification need to be confirmed in different samples
Mechanism of occupational asthma
No full textInhalation of agents in the workplace can induce asthma in a relatively small proportion of exposed workers. Like nonoccupational asthma, occupational asthma is probably the result of multiple genetic, environmental, and behavioral influences. It is important that occupational asthma be recognized clinically, because it has serious medical and socioeconomic consequences. Environmental factors that can affect the initiation of occupational asthma include the intrinsic characteristics of causative agents, as well as the influence of the level and route of exposure at the workplace. The identification of host factors, polymorphisms, and candidate genes associated with occupational asthma may improve our understanding of mechanisms involved in asthma. High-molecular-weight compounds from biological sources and low-molecular-weight chemicals cause occupational asthma after a latent period of exposure. Although the clinical, functional and pathologic features of occupational asthma caused by low-molecular-weight agents resemble those of allergic asthma, the failure to detect specific immunoglobulin E antibodies against most low-molecular-weight agents has resulted in a search for alternative or complementary physiopathologic mechanisms leading to airway sensitization. Recent advances have been made in the characterization of the immune response to low-molecular-weight agents. In contrast, the mechanism of the form of occupational asthma that occurs without latency after high-level exposure to irritants remains undetermined
Remodeling in response to infection and injury - Airway inflammation and hypersecretion of mucus in smoking subjects with chronic obstructive pulmonary disease
No full textNeutrophils and Asthma
No full textThe importance of inflammation in asthma has been recognized for a long time and recently proved in man and animal models. All inflammatory cells are probably involved in exacerbations of asthma. Neutrophils in particular are present in the airways during and after the spontaneous asthma attacks in man and during asthmatic reactions and airway hyperresponsiveness induced experimentally in man and animals. Depletion of neutrophils prevents these effects and repletion with neutrophils reconstitutes them. Moreover, the supernatant from stimulated human neutrophils causes transient hyperresponsiveness. However, neutrophils are not increased in stable asthmatics with hyperreactive airways and are not involved in airway hyperresponsiveness induced experimentally in some animals (e.g. guinea-pigs). The studies reviewed suggest that neutrophils may be involved in the transient increases of airway responsiveness associated with exacerbations of asthma, but not in the long-lasting hyperresponsiveness of stable asthmatics
Patologia amianto-correlata in soggetto non fumatore di sesso femminile
No full textThe study presents a case of a 62-year-old female, non-smoker, occupationally exposed for 6 years to high concentrations of asbestos, who has developed benign pleural effusion, pleural plaques, asbestosis and lung cancer. This case report confirms that brief exposure to high doses of asbestos can induce different asbestos-related diseases in the same subject
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
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