The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Although negative pressure assisted ventilation with an assist-control mode may have a potential therapeutic role in the treatment of severe dyspnoea, the effects of negative pressure assisted ventilation with the assist-control mode on dyspnoea and breathing patterns have not been examined. We examined the effects of negative pressure assisted ventilation with the assist-control mode on dyspnoea and breathing patterns produced by a combination of resistive loading and hypercapnia in nine healthy subjects breathing spontaneously. ⋯ During negative pressure assisted ventilation, there were significant changes in breathing patterns characterized by an increase in tidal volume and a decrease in respiratory frequency, while neither minute ventilation nor end-tidal carbon dioxide tension changed. Our results indicate that negative pressure assisted ventilation with the assist-control mode is effective in relief of dyspnoea and that negative pressure assisted ventilation influences the control of breathing to minimize respiratory discomfort.
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The role of genetic factors has been hypothesized in the pathogenesis of a number of chronic inflammatory lung diseases. The genes of the major histocompatibility complex (MHC) locus on human chromosome 6 have been identified as important determinants in diseases caused both by inorganic and organic compounds such as beryllium, gold, acid anhydrides, isocyanates and grass pollens. Since many environmental factors are the determinants of the immunopathogenesis of asthma, pulmonary granulomatous disorders, hypersensitivity pneumonitis and fibrotic lung disorders, an understanding of the interaction between environmental factors is crucial to epidemiology, prevention and treatment of these disorders. ⋯ In in vitro studies, the gene has been shown to play a direct role in the immunopathogenesis of the disease. In human studies, the gene has been shown to confer increased susceptibility to beryllium in exposed workers, thus suggesting that HLA gene markers may be used as epidemiological probes to identify population groups at higher risk of environmental lung diseases, to identify environmental levels of lung immunotoxicants that would be safe for the entire population and to prevent disease risk associated with occupation, manufactured products and the environment. Studies on the associations between human leukocyte antigens and chronic inflammatory lung disorders are reviewed in the context of the berylliosis model.
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Talc administration into the pleural cavity induces pleurodesis. To obtain further insight into the inflammatory process that causes pleurodesis, the cellular kinetics in the pleural space after the administration of talc was studied, along with its relation to chemokine concentrations in the pleural fluid. Thirteen consecutive patients with idiopathic spontaneous pneumothorax and eight patients with malignant pleural effusions received talc pleurodesis. ⋯ The talc-induced PMN influx reached its maximum after 3-24 h, and was related to the IL-8 concentration. In contrast, the MCP-1 was not related to the macrophage accumulation. Talc-induced inflammation in patients with idiopathic spontaneous pneumothorax and malignant pleural effusion is characterized by an influx of polymorphonuclear neutrophils related to interleukin-8, followed by an accumulation of monocytes.