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)

Prolonged ischemia to skeletal muscle as occurs after an acute arterial occlusion results in alterations in adenine nucleotide metabolism. Adenosine triphosphate continues to be used for cellular functions, and an ischemia-induced degradation of phosphorylated adenine nucleotides is initiated. In this experiment we demonstrated the time-dependent aspect of adenine nucleotide depletion during ischemia and the production of large quantities of soluble precursors. In addition, we studied the rate of conversion of xanthine dehydrogenase to xanthine oxidase, a potential source of oxygen-free radicals, after controlled periods of total normothermic ischemia (4 hours and 5 hours) and during the reperfusion phase. During ischemia complete depletion of creatine phosphate occurred in both groups, and adenosine triphosphate fell from 22.1 +/- 1.3 to 10.3 +/- 1.4 mumol/gm dry weight after 4 hours and from 21.6 +/- 0.7 to 3.9 +/- 0.8 mumol/gm dry weight after 5 hours (p less than 0.05). During reperfusion, creatine phosphokinase resynthesis occurred in both groups, but adenosine triphosphate levels were not significantly increased (p greater than 0.05). A washout of lipid soluble products of adenine nucleotide metabolism occurred equally in both groups. The relationship between phosphorylated adenine nucleotides as measured by the energy charge potential fell significantly in both groups (p less than 0.05), but after the shorter period of ischemia (4 hours it returned to normal during early reperfusion but did not after 5 hours of ischemia. There was 21% +/- 4% necrosis after 4 hours and 51% +/- 8% after 5 hours of ischemic stress when assessed at 48 hours. In conclusion, the degree of adenine nucleotide degeneration as determined primarily by the length of the ischemic period, may be the most important determinant of the ultimate extent of skeletal muscle ischemic necrosis that results from an acute interruption of circulation.
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PMID:The effect of ischemia/reperfusion on adenine nucleotide metabolism and xanthine oxidase production in skeletal muscle. 237 59

Human serum albumin (HSA) is being considered as an alternate media for sperm enrichment in assisted reproductive technology (ART) because of recent concern with the use of Percoll. In this study, we compared HSA and Percoll for 1) sperm recovery, 2) reactive oxygen species scavenging potential, and 3) effects on total oxidative stress to spermatozoa. The spermatozoa-enriched fractions obtained from Percoll (80%:40%) and HSA (12%) were monitored for sperm motility, viability, hypoosmotic swelling test (HOST), and adenosine triphosphate (ATP) levels. The effect of superoxide anions (O2.-) on donor human spermatozoa was observed in the presence of either HSA or Percoll media. A combination of luminol and the Cypridina luciferin analog 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyraz in-3-one hydrochloride was used as a highly sensitive chemiluminescence probe in our hypoxanthine and xanthine oxidase-based assay for O2.-. Sperm membrane total oxidative stress was determined by measuring levels of the prostanoid 8-iso-Prostaglandin F2alpha (8-iso-PGF2alpha). Significant differences in sperm parameters between the Percoll-enriched spermatozoa (motility 60%+/-4%, viability 56%+/-6%, and HOST 73%+/-7%) and those enriched with HSA (motility 84%+/-5%, viability 85%+/-4%, and HOST 84%+/-3%; P < 0.01) were observed. Adenosine triphosphate levels were significantly higher, by almost 50%, in samples processed with HSA than with Percoll (P=0.03). The dismutation rate of O2.- in HSA (slope -6.8) was significantly lower than in Percoll (slope -87.0; P < 0.01). Sperm motility and ATP levels decreased at a slower rate after treatment with O2.- in the presence of HSA when compared to Percoll; moreover, spermatozoa in HSA regained partial motility after 2 hours, whereas spermatozoa in Percoll were immobilized. No significant differences in 8-iso-PGF2alpha levels in spermatozoa enriched by either HSA or Percoll were observed. We conclude that the HSA sperm enrichment procedure improves the recovery of higher quality spermatozoa compared to Percoll and, because of its antioxidant properties, may be useful in processing high leukospermia semen samples for ART purposes.
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PMID:Antioxidant potential of human serum albumin: role in the recovery of high quality human spermatozoa for assisted reproductive technology. 973 43