Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.17.3.2 (xanthine oxidase)
 8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Xanthine oxidase (xanthine: oxygen oxidoreductase, EC 1.1.3.22), a molybdenum-containing hydroxylase that produces superoxide and uric acid from purine substrates and molecular oxygen, is involved in the oxidative stress underlying several human pathologies including lung diseases. An enzymatic activity similar to xanthine oxidase was previously reported in bronchoalveolar lavage fluid of patients with chronic obstructive pulmonary disease (COPD-BAL), by fluorometric analysis of DNA unwinding and cytochrome c reduction kinetics. Here we report the detection of xanthine oxidase activity products by electron paramagnetic resonance (EPR) in presence of the spin-trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and reversed-phase high-performance liquid chromatography (RP-HPLC) in COPD-BAL (n = 14, average age of patients 65 years, range 38-81) and BAL from healthy nonsmoker controls (n = 6, average age 64 years, range 44-73). Superoxide DMPO adducts were detected in COPD-BAL and in an in vitro system containing xanthine and xanthine oxidase (XA/XO), but not in BAL controls and when superoxide dismutase (SOD, 1000 I.U./ml) was added to COPD-BAL. The HPLC analyses after addition of xanthine showed production of uric acid in COPD-BAL and in the XA/XO system but not in BAL controls. These results support the involvement of xanthine oxidase in the mechanisms of superoxide production by BAL supernatant, which increases oxidative stress in chronic obstructive pulmonary disease.
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PMID:Detection of xanthine oxidase activity products by EPR and HPLC in bronchoalveolar lavage fluid from patients with chronic obstructive pulmonary disease. 982 42

Cl(2) gas toxicity is complex and occurs during and after exposure, leading to acute lung injury (ALI) and reactive airway syndrome (RAS). Moreover, Cl(2) exposure can occur in diverse situations encompassing mass casualty scenarios, highlighting the need for postexposure therapies that are efficacious and amenable to rapid and easy administration. In this study, we assessed the efficacy of a single dose of nitrite (1 mg/kg) to decrease ALI when administered to rats via intraperitoneal (ip) or intramuscular (im) injection 30 min after Cl(2) exposure. Exposure of rats to Cl(2) gas (400 ppm, 30 min) significantly increased ALI and caused RAS 6-24h postexposure as indexed by BAL sampling of lung surface protein and polymorphonucleocytes (PMNs) and increased airway resistance and elastance before and after methacholine challenge. Intraperitoneal nitrite decreased Cl(2)-dependent increases in BAL protein but not PMNs. In contrast im nitrite decreased BAL PMN levels without decreasing BAL protein in a xanthine oxidoreductase-dependent manner. Histological evaluation of airways 6h postexposure showed significant bronchial epithelium exfoliation and inflammatory injury in Cl(2)-exposed rats. Both ip and im nitrite improved airway histology compared to Cl(2) gas alone, but more coverage of the airway by cuboidal or columnar epithelium was observed with im compared to ip nitrite. Airways were rendered more sensitive to methacholine-induced resistance and elastance after Cl(2) gas exposure. Interestingly, im nitrite, but not ip nitrite, significantly decreased airway sensitivity to methacholine challenge. Further evaluation and comparison of im and ip therapy showed a twofold increase in circulating nitrite levels with the former, which was associated with reversal of post-Cl(2) exposure-dependent increases in circulating leukocytes. Halving the im nitrite dose resulted in no effect in PMN accumulation but significant reduction of BAL protein levels, indicating a distinct nitrite dose dependence for inhibition of Cl(2)-dependent lung permeability and inflammation. These data highlight the potential for nitrite as a postexposure therapeutic for Cl(2) gas-induced lung injury and also suggest that administration modality is a key consideration in nitrite therapeutics.
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PMID:Administration of nitrite after chlorine gas exposure prevents lung injury: effect of administration modality. 2291 77