Proceedings of the American Thoracic Society
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Review
Sensory detection and responses to toxic gases: mechanisms, health effects, and countermeasures.
The inhalation of reactive gases and vapors can lead to severe damage of the airways and lung, compromising the function of the respiratory system. Exposures to oxidizing, electrophilic, acidic, or basic gases frequently occur in occupational and ambient environments. Corrosive gases and vapors such as chlorine, phosgene, and chloropicrin were used as warfare agents and in terrorist acts. ⋯ Animal studies using TRPA1 antagonists or TRPA1-deficient mice confirmed the role of TRPA1 in chemically induced respiratory reflexes, pain, and inflammation in vivo. New research shows that sensory neurons are not merely passive sensors of chemical exposures. Sensory channels such as TRPA1 are essential for maintenance of airway inflammation in asthma and may contribute to the progression of airway injury following high-level chemical exposures.
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Coccidioidomycosis is a growing problem in the endemic regions of Arizona and California. The reasons for its increase are unclear, but may relate to an influx of nonsusceptible individuals into the endemic regions, construction and dust, and climate. Most cases of coccidioidal infection are completely asymptomatic, but approximately 40% present as a pulmonary process that may be difficult to distinguish from a bacterial community-acquired pneumonia. ⋯ Newer tests, including detection of coccidioidal antigenuria and genomic assays, offer promise of greater sensitivity, specificity, and rapidity. The treatment of coccidioidomycosis has most recently depended on oral triazole therapy. However, a recent study suggests that, at least for those with primary pulmonary disease, antifungal therapy may lead to subsequent complications once this therapy is discontinued compared with those who receive no therapy at all.
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Epidemiology has played an important role in the understanding of air pollution as a risk factor for respiratory disease and in the evidence base for air quality standards. With the widespread availability of genetic information and increasingly sophisticated measurements of molecular markers of adverse effects, there is a need for more specific and precise assessment of exposure to maximize the potential information to be derived from epidemiologic studies. Here advances in air pollution exposure assessment and their applications to studies of respiratory disease are reviewed, with a focus on recent studies of traffic-related air pollution and asthma. ⋯ Recent applications of geospatial (e.g., land use regression) models to studies of respiratory disease have made possible new study designs focused on spatial variability in exposure within urban areas and have provided new insights into the potential role of traffic-related air pollution (TRAP) as a risk factor for the development of childhood asthma. Substantial uncertainty remains, however, regarding what agent(s) within TRAP might be responsible for the observed associations. Future research will require increasing the specificity of exposure assessment to identify the potential roles of individual air pollution components, to elucidate potential mechanisms, and to facilitate studies of mixtures and gene-air pollution interactions.
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Blastomycosis is an endemic mycosis that occurs predominantly in North America in the north central United States and provinces of Canada, southern states, and those midwestern states that border the Mississippi River basin. It causes acute and chronic pneumonias and disseminated infection with cutaneous lesions as the major extrapulmonary manifestation. However, the vast majority of infected persons are asymptomatic or have mild respiratory symptoms that are not diagnosed as being caused by a fungal infection. ⋯ A urinary antigen test is now available to aid in diagnosis, but it is not specific and is positive in patients who have histoplasmosis as well as blastomycosis. Antibody assays remain nonspecific and insensitive, and the confirmatory diagnostic test is still growth of the organism in culture. Updated guidelines from the Infectious Diseases Society of America are available to aid clinicians in the management of the various forms of blastomycosis.
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Histoplasmosis is the most prevalent endemic fungal infection in North America. The clinical spectrum ranges from asymptomatic, self-limited illness to a life-threatening progressive disseminated disease. Chronic manifestations of healed infection can also be problematic. ⋯ The preferred diagnostic methods and treatment options vary with clinical scenario and severity of illness. New diagnostic tools and treatment options are now available in clinical practice. We present an overview of this important endemic mycosis with emphasis on diagnosis and treatment recommendations for the different clinical syndromes of histoplasmosis.