Plasma Xanthine Oxidase Activity Research Articles

Urine xanthine oxidase activity in urinary tract infection.

Xanthine oxidase (XO) activity was found to be negligible in sterile human urines (less than 480 units, as presently defined, per litre). Significant XO activity was found in all urines containing more than 10(5) bacteria/ml, except for urines infected with Staphylococcus aureus, in which XO activity ranged from 347 to 714 units per litre. Plasma XO is not transferred to the urine, as demonstrated by the negligible XO activity found in sterile urines from patients with raised plasma XO activity. Determination of urinary XO activity is a suitable procedure for the detection of urinary tract infection.

A method for determination of the inhibition of xanthine oxidase activity in plasma during allopurinol treatment

A micromethod suitable for measuring the combined blood levels of allopurinol and alloxanthine has been developed. The two compounds display marked inhibition of xanthine oxidase activity (Ki=6.3×10−10 and 5.4×10−10 M), so the amounts found in 20 µl serum from allopurinol-treated patients can cause marked inhibition of xanthine oxidase activity in vitro under appropriate conditions. If the concentrations of compounds acting in an ‘allopurinol-like’ manner are expressed in terms of allopurinol, activity equivalent values are obtained which reflect the effective drug concentration during therapy. The procedure is simple and suitable for serial examinations. It also satisfies the demands of the clinician, in that it can reveal any disturbance in the absorption of allopurinol and in excretion of the drug and its active metabolite, alloxanthine.

Activité xanthine-oxydasique rénale, hépatique et san-guine chez le rat au cours de l'intoxication expérimentale au nitrate d'uranyle

In uranyl nitrate-induced tubulonephritis in the rat with toxic hepatitis, the following observations were made: significant decrease, during 24 hours, of the renal xanthine oxidase activity followed by a very marked rise at the 96th hour after the beginning of the intoxication; more clear-cut fall of the liver xanthine oxidase activity as soon as the 24th hour, followed by slight reactivation and by continuous decrease until the 96th hour; rise in the plasma xanthine oxidase activity, with its maximum at the 48th hour. The contents in proteins, DNA and RNA as well as the hematocrits were studied.