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

Acute mesenteric ischemia is highly lethal and therefore a serious problem for surgery and intensive care medicine; accordingly its pathophysiology warrants further study. Oxygen free radicals (OFR) play a role in the intestinal mucosal damage that develops during reperfusion after ischemia. Histamine (H) is generally released in various types of tissue ischemia. The link between H release and OFR has only been studied in in vitro systems. We tested the hypothesis that OFR may be involved in H release following reperfusion of the ischemic gut. The artery supplying a segment of the ileum was occluded for 1 or 2 h in anesthetized dogs. On reperfusion, a release of H into the venous effluent of the segment was demonstrated. Pretreatment of the animals with allopurinol (an inhibitor of xanthine oxidase), or with MTDQ-DA [6,6'-methylene-bis(2,2-dimethyl-4-methanesulfonic acid sodium-1,2-dihydroquinoline)], a superoxide anion scavenger, or with a combination of allopurinol and MTDQ-DA resulted in an inhibition of H release. We conclude that OFR may play a role in the local H release following intestinal ischemia.
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PMID:Oxygen free radical-induced histamine release during intestinal ischemia and reperfusion. 248 33

The abilities of 15 flavonoids as a scavenger of active oxygens (hydroxyl radical and superoxide anion) were studied. Hydroxyl radical (.OH) was generated by the Fenton system, and assayed by the determination of methanesulfonic acid (MSA) formed from the reaction of dimethyl sulfoxide (DMSO) with .OH. (+)-Catechin, (-)-epicatechin, 7,8-dihydroxy flavone, and rutin showed the .OH scavenging effect 100-300 times superior to that of mannitol, a typical .OH scavenger. The other flavonoids showed no .OH scavenging effect at their concentrations up to 50 microM. Baicalein, quercetin, morin, and myricetin unexpectedly increased the .OH production in the Fenton system. The flavonoids tested now, except monohydroxy flavones, were more or less inhibitive to the superoxide anion (O2) generation in the hypoxanthine-xanthine oxidase system. A great part of this inhibitory effect was likely owing to suppression of xanthine oxidase activity by the flavonoids. The flavonoids, which scavenged .OH or O2-, were necessarily antioxidants to the peroxidation of methyl linoleate. However, there was a type of flavonoid such as morin, which have neither .OH nor O2- scavenging effect, but was a strong antioxidant.
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PMID:The correlation between active oxygens scavenging and antioxidative effects of flavonoids. 807 Jun 90