Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P47989 (xanthine oxidase)
 8,633 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reactive oxygen species mediate injury and inflammation in many tissues. The addition of xanthine and xanthine oxidase to perfused rat lungs led to increases in peak airway pressure and perfusion pressure, pulmonary edema, and increased protein content in bronchoalveolar lavage fluid. Treatment with 1-10 micrograms.kg-1.min-1 of vasoactive intestinal peptide (VIP), a widely distributed neuropeptide, markedly reduced or totally prevented all signs of injury. Simultaneously, VIP also diminished or abolished the associated generation of arachidonate products. Similar protection was provided by catalase (100 micrograms/ml) but not by the VIP-related peptides secretin or glucagon. The pulmonary vasodilator papaverine (0.15 mg/ml) was also ineffective. Injured lungs that were not treated with VIP released large amounts of this peptide in the perfusate. The results indicate that VIP has potent protective activity against injury triggered by xanthine/xanthine oxidase and may be a physiological modulator of inflammatory tissue damage associated with toxic oxygen metabolites.
 ...
PMID:Vasoactive intestinal peptide prevents lung injury due to xanthine/xanthine oxidase. 238 32

Recent experimental work has suggested that oxygen-derived free radicals may play an important role in initiating the early capillary injury in acute pancreatitis. Data from models of ischemic injury in other organs have suggested the enzyme xanthine oxidase is important in generating oxygen-derived free radicals. The present study was performed to determine whether xanthine oxidase is the source of free radical production in experimental pancreatitis. Utilizing the isolated, perfused, ex vivo canine pancreas preparation, three models of pancreatitis were initiated with (1) free fatty acid infusion (FFA), (2) partial duct obstruction and secretin stimulation (POSS), and (3) ischemia (ISCH). In each model, during a 4-hour perfusion, edema developed, weight gain occurred (FFA 120.6 +/- 21.1 gm; POSS 44.5 +/- 6.9 gm; ISCH 63.3 +/- 14.0 gm), and the serum amylase became elevated (FFA 1827 +/- 397 u/dl; POSS 10,171 +/- 1487 u/dl; ISCH 1860 +/- 365 u/dl). When the xanthine oxidase enzyme inhibitor allopurinol was added to the perfusate prior to the 4-hour perfusion, edema formation was absent or minimal, weight gain was significantly less (FFA 15.2 +/- 2.5 gm p less than 0.05; POSS 8.8 +/- 2.7 gm p less than 0.001; ISCH 12.3 +/- 2.8 gm p less than 0.01), and the amylase remained normal or the elevation was significantly decreased (FFA 996 +/- 189 u/dl p less than 0.05; POSS 3021 +/- 1074 u/dl p less than 0.001; ISCH 993 +/- 214 u/dl p less than 0.002). These data confirm that oxygen-derived free radicals play an important role in the pathogenesis of experimental acute pancreatitis, and suggest that the enzyme xanthine oxidase may well be the source of their production.
 ...
PMID:The pathogenesis of acute pancreatitis. The source and role of oxygen-derived free radicals in three different experimental models. 258 19

We earlier showed that the neuropeptide vasoactive intestinal peptide (VIP) reduces or prevents acute injury produced in rat lungs by xanthine and xanthine oxidase. We have now examined whether VIP can protect against lung injury induced by paraquat, a prooxidant pesticide. Isolated guinea pig lungs were perfused for 60 min with Krebs-4% albumin and mechanically ventilated with 95% O2-5% CO2. Infusion of paraquat (100 mg/kg) into the pulmonary artery (n = 9 observations) increased peak airway pressure from 10.1 +/- 0.6 to 54.7 +/- 6.5 cmH2O, perfusion pressure from 8.0 +/- 0.5 to 14.9 +/- 3.0 cmH2O, wet-to-dry lung weight ratio to 7.17 +/- 0.37, and bronchoalveolar lavage protein content to 2.70 +/- 0.83 mg/ml (P < 0.01). Pretreatment with 1-3 micrograms.kg-1 x min-1 VIP markedly attenuated or prevented all abnormalities. Of the related peptides tested, helodermin was as effective as VIP, but secretin and glucagon were ineffective. The results demonstrate that VIP and helodermin protect perfused guinea pig lungs against paraquat-induced injury and support the view that VIP has antioxidant activity.
 ...
PMID:Paraquat-induced lung injury: prevention by vasoactive intestinal peptide and related peptide helodermin. 823 70

Four models of acute pancreatitis have been previously developed that use the ex vivo perfused isolated canine pancreas preparation. The four models include the intraarterial infusion of oleic acid (FFA) that mimics hyperlipemic pancreatitis, partial obstruction of the pancreatic duct with secretin stimulation (POSS) that mimics gallstone pancreatitis, a 2-hour period of ischemia before perfusion (ISCH 2) that mimics shock pancreatitis, and the infusion of cerulein at supramaximal stimulatory doses (CER), which lacks an obvious clinical counterpart. In the FFA, POSS, and ISCH 2 pancreatitis, but not in the CER pancreatitis, toxic oxygen metabolites, generated by the enzyme xanthine oxidase (XO), have been shown to be important mediators in the early pathogenesis. Ordinarily XO primarily occurs as xanthine dehydrogenase (XD) but can be converted to XO, which is the form that generates toxic oxygen metabolites. This conversion of XD to XO may take place either reversibly by way of sulfhydryl group oxidation or irreversibly by means of proteolytic cleavage of XD. This study was undertaken to investigate the mechanism of conversion of XD to XO in the FFA-, POSS-, and ISCH 2-induced pancreatitis models. CER pancreatitis was studied for comparison. After 4 hours of perfusion, pancreatitis was manifest by edema, weight gain, and hyperamylasemia in all four models. Dithiothreitol, a sulfhydryl group protector, ameliorated the weight gain in the FFA (40 +/- 14 gm to 18 +/- 13 gm; p < 0.05), POSS (28 +/- 10 gm to 9 +/- 3 gm; p < 0.05), and ISCH 2 pancreatitis (30 +/- 13 gm to 15 +/- 3 gm; p < 0.05), and ameliorated the hyperamylasemia in the POSS pancreatitis (12,062 +/- 4304 units/dl to 5877 +/- 2659 units/dl; p < 0.05). The CER pancreatitis was not ameliorated with dithiothreitol. A serine protease inhibitor of low molecular weight, phenylmethylsulfonyl fluoride, ameliorated only the CER pancreatitis (weight gain from 28 +/- 10 gm to 17 +/- 10 gm, p < 0.05; amylase activity from 38,116 +/- 6491 units/dl to 23,372 +/- 11,654 units/dl, p < 0.05), and not the FFA, POSS, or ISCH 2 pancreatitis. We conclude that in the three models of pancreatitis (FFA, POSS, and ISCH 2) that are mediated by toxic oxygen metabolites, XD is converted to XO reversibly by way of sulfhydryl group oxidation rather than irreversibly by way of proteolysis. In the CER pancreatitis, where XO does not play a role in the pathogenesis, proteolytic enzymes may be important mediators in the injury.
 ...
PMID:The mechanism of conversion of xanthine dehydrogenase to xanthine oxidase in acute pancreatitis in the canine isolated pancreas preparation. 841 95

The current study was done to evaluate the effects of short term (60 minutes) pancreatic biliary duct obstruction (PBDO) with intraductal hypertension (IDH) stimulated by secretin (0.2 clinical unit per kilogram per hour) and caerulein (0.2 microgram per kilogram per hour) plus 30 minutes of temporary pancreatic ischemia (ISCH) produced by ligation of celiac and superior mesenteric artery on the exocrine pancreas and protective effects of a new potent protease inhibitor, ONO3307 in combination with xanthine oxidase inhibitor, allopurinol, in this multifactor related model of acute pancreatitis in rats. Twelve hours after PBDO with IDH plus ISCH, we observed hyperamylasemia (23 +/- 3 units per milliliter) (p < 0.01); moderate pancreatic histologic changes; pancreatic edema (water content--81 +/- 2 percent) (p < 0.02), as well as the impaired amylase (2,889 +/- 328 units per kilogram per hour) (p < 0.01) and cathepsin B output (7 +/- 3 units per kilogram per hour) (p < 0.01) into the pancreatic juice of rats stimulated by caerulein (control group--serum amylase levels, 6 +/- 1 units per milliliter; pancreatic water content, 74 +/- 1 percent. Furthermore, PBDO with IDH plus ISCH caused the redistribution of lysosomal enzyme from lysosomal fraction (12 kilo times gravity pellet; 40 +/- 3 percent; p < 0.01) to zymogen fraction (1.3 kilo times gravity pellet; 38 +/- 3 percent; p < 0.01) (control group--12 kilo times gravity pellet, 59 +/- 2 percent; 1.3 kilo times gravity pellet, 24 +/- 2 percent) and the impaired pancreatic adenylate energy metabolism (0.79 +/- 0.02, p < 0.02) (control group--energy charge equals 0.88 +/- 0.01). Only PBDO with IDH caused no significant changes. Although only ONO3307 or allopurinol therapy showed the partial significant protective effects against pancreatic injuries, improving serum amylase levels, the administration of ONO3307 in combination therapy with allopurinol showed almost complete protective effects against the pancreatic injuries induced by PBDO with IDH plus ISCH (serum amylase levels, 9 +/- 2 units per milliliter; pancreatic water content, 76 +/- 2 percent; amylase and cathepsin B output, 7,127 +/- 946 and 18 +/- 3 units per kilogram per hour; 1.3 kilo times gravity pellet, 28 +/- 2 percent; 12 kilo times gravity pellet, 54 +/- 2 percent, and energy charge equals 0.85 +/- 0.02).(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Protective effects of therapy with a protease and xanthine oxidase inhibitor in short form pancreatic biliary obstruction and ischemia in rats. 846 Apr 15