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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Normobaric oxygen toxicity is well described in all animal species. However susceptibility to oxygen exposure is highly variable according to age, species and strains. Similarly in humans, prolonged high oxygen exposure is reported to induce cough, shortness of breath, decrease vital capacity and increase alveolo-capillary permeability. The toxic FIO2 threshold (length of exposure and level) is still debated. In patients with previous lung injury, this threshold is even more difficult to delineate as pathologic pulmonary lesions might result from hyperoxia or primary lung insult. Oxygen free-radicals play a key role in the pathophysiology of oxygen toxicity. Oxygen resistance or tolerance is obtained with intraperitoneal, intravenous and intratracheal endotoxin or cytokines administration. Previous exposure to high oxygen concentration is also reported to increase survival rate and decrease pulmonary lesions in animal models. Protection may rely on antioxidant enzymes synthesis, nitric oxide production, neutrophils recruitment and modulation of alveolar macrophages activity. In humans, oxygen tolerance might be suspected through several clinical studies reporting favorable outcome after long term-oxygen exposure. Better knowledge of the risks of prolonged high oxygen exposure is important to re-evaluate the goals of mechanical ventilation (FIO2, SaO2, PEEP) and/or to develop treatments to prevent oxygen toxicity (surfactant, antioxidant enzymes).
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PMID:Oxygen toxicity and tolerance. 1039 7

We are living in an environment full of gases, and any change in the concentration of a component of the air or contaminants (usually toxic) in the air may significantly threaten human health. Thus, to investigate the influence of gases in animal models it is helpful to elucidate the pathogenesis of gas-related injury. Although there are devices used for gas exposure in animals, there are still limitations in the establishment of these animal models, such as the change in gas concentration during the refreshing of water, food and litter, and the contamination of toxic gases released by animals. Herein, we freshly prepared a chamber for normobaric gas exposure. During the exposure in this chamber, the refreshing of water, food and litter does not require opening of the chamber. The chamber gases are continuously circulated and filtered, and the gas concentration remains very stable. To validate the feasibility of this chamber, rats were exposed to pure oxygen as an example. Results showed that rats with hyperoxia-induced lung injury simulated by pure oxygen exposure displayed the representative characteristics as observed in humans: shortness of breath, lung edema, alveolar septal rupture, infiltration of inflammatory cells, oxidative and inflammatory injury. This suggests that it is feasible to establish animal models using this chamber for the investigation of gas toxicity.
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PMID:A normobaric gas exposure animal chamber and its validation in hyperoxia exposure. 2659 77