Annals of the American Thoracic Society
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Viral infection represents a common and problematic health care issue, particularly in younger and senior populations. The respiratory tract is a major portal for microbial exposure, where viral infection can result in nonsymptomatic, mild, and self-limiting or severe and sometimes fatal infection. ⋯ Moreover, human studies of airway microbiota after pH1N1 demonstrate that the composition of the respiratory microbiome can be modified by viral infection in a manner that enriches for pathogens associated with secondary bacterial infection. In this article, current knowledge in the field of human microbiome research, particularly as it pertains to respiratory viral infection, is reviewed.
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Randomized Controlled Trial
Acetazolamide attenuates Hunter-Cheyne-Stokes breathing but augments the hypercapnic ventilatory response in patients with heart failure.
Acetazolamide has been used to attenuate Hunter-Cheyne-Stokes breathing with central sleep apnea (CSA) associated with heart failure. However, the mechanisms underlying this improvement remain to be fully elucidated. ⋯ This placebo-controlled study indicates that acetazolamide improves CSA in patients with heart failure despite an increase in the slope of the HCVR. However, because the degree of HCVR elevation inhibits the improvement in unstable breathing, an increased CO2 chemosensitivity may be a key mechanism underlying an incomplete resolution of CSA with acetazolamide.
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Microbes are readily cultured from epithelial surfaces of the skin, mouth, and colon. In the last 10 years, culture-independent DNA-based techniques demonstrated that much more complex microbial communities reside on most epithelial surfaces; this includes the lower airways, where bacterial culture had failed to reliably demonstrate resident bacteria. Exposure to a diverse bacterial environment is important for adequate immunological development. ⋯ Furthermore, rhinovirus infection leads to outgrowth of Haemophilus in patients with chronic obstructive pulmonary disease, and human immunodeficiency virus-infected subjects have more Tropheryma whipplei in the lower airway, suggesting a bidirectional interaction in which the host immune defenses also influence the microbial niche. Quantitative and/or qualitative changes in the lung microbiome may be relevant for disease progression and exacerbations in a number of pulmonary diseases. Future investigations with longitudinal follow-up to understand the dynamics of the lung microbiome may lead to the development of new therapeutic targets.
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Lung and cardiovascular disease are increasingly recognized to occur in the same patient populations. Infections, either through stimulation of inflammation or through direct infection, can lead to end-organ damage and have been postulated as a potential link between lung and cardiovascular diseases. ⋯ These relationships are likely quite complex, with multiple routes between infection and disease possible. A better understanding of the links of infection to lung and heart disease can improve our understanding of the pathogenesis of these disorders and uncover novel therapeutic approaches.