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Query: UMLS:C0034063 (pulmonary edema)
 10,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The toxicity of ozone is solely due to its action as an oxidant. It is an extremely reactive gas which rapidly forms intermediate oxidizing derivatives after inhalation. High concentrations cause death from pulmonary oedema. Both pulmonary and extrapulmonary toxicity have been observed at lower concentrations of ozone, including those currently present in urban air. Pulmonary cellular and subcellular membranes appear to be particularly susceptible. A primary mechanism of this effect is the oxidative decomposition of polyunsaturated fatty acids, which has been demonstrated in rodent lungs after inhalation of ozone. Supporting evidence includes the potentiation of ozone toxicity by vitamin E deficiency and an increased use of this antioxidant vitamin during repetitive exposure to ozone. Other membrane effects include oxidation of thiol groups and, perhaps, of tryptophan. Microsomal alterations include a loss of lung cytochrome P450 which may also be related to lipid peroxidation. Extrapulmonary toxicity is not directly due to ozone but may represent in effect due to lipid peroxide decomposition products, particularly malonaldehyde. This three-carbon dialdehyde has been shown to alter cell membrane fluidity and to have mutagenic properties; the latter perhaps due to cross-linkage of DNA to histone.
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PMID:The pulmonary and extrapulmonary effects of ozone. 25 63

In 1969 McCord and Fridovich discovered superoxide dismutase, which converts the oxygen free radical O(2) (-) to hydrogen peroxide H(2)O(2). In the presence of excess O(2) (-), H(2)O(2) may then undergo further reduction to the highly toxic hydroxyl radical, OH(*). Since the description of this enzymatic process, there has been explosive growth in related biochemical research, which has now percolated through to clinical investigation. The hypoxanthine-xanthine oxidase system originally used as a radical production model has a close counterpart in the ischemia-reperfusion phenomenon purported to cause diseases of heart, brain and gastrointestinal tract, and free radicals are now known to have a critical role in postphagocytic bacterial killing. Prototypic deficiency diseases such as chronic granulomatous disease are now recognized. Some evidence indicates that excess states such as perhaps Batten's disease also occur, and environmental influences such as selenium and vitamin E deficiency may augment free radical levels. Many disorders including microvasculopathies, noncardiogenic pulmonary edema, glomerulopathies and radiation damage may owe part of their proximate pathogenesis to free radicals. Control of tissue free radical levels is now pharmacologically feasible and perhaps justified for specific diseases.
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PMID:The expanding role of oxygen free radicals in clinical medicine. 352 Oct 94