[Xanthine oxidase activity: NAD+-dependent and O2-dependent forms in carrageenan granuloma in the rat]. / Activité de la xanthine oxydase: formes nad+-dépendante et o2-dépendante dans le granulome à la carragénine chez le rat.

Xanthine oxidase activity: NAD+-dependent form (D) and O2-dependent form (O) were carried out in cytosol supernatants of connective tissue growth (T.C.N.F.), skin tail, liver and plasma of carrageenan induced granuloma in the Rat. The specific activities of skin, liver and plasma were normal in animals with a granuloma. The total specific activity (D + O): 7.53 +/- 0.98 mU/mg protein, and the percentage of form O: 51.6 +/- 5.1 of the granulomatous tissue as compared to the tail are significantly increased. These results suggest the likely function of xanthine oxidase during the inflammatory response.

[Xanthine oxidase activity: O2-dependent and NAD+-dependent forms in the liver, in rats with adjuvant arthritis and hepatitis]. / Activité de la xanthine oxydase: formes O2-dépendante et NAD+-dépendante du foie, chez le rat atteint d'arthrite et d'hépatite à adjuvant.

Xanthine oxidase activity: O2-dependent and NAD+-dependent forms, were carried out in cytosol supernatant of Rat liver homogenat with adjuvant and hepatocytes induced arthritis and hepatitis. Both forms were increased without modification of their ratio. These results suggest that xanthine oxidase was implicated in the inflammatory reaction.

Pharmacokinetic parameters of 14C oxithiopurinol in rat.

The study with labelled compound has shown that in rat, as in man, thiopurinol is primarily and rapidly converted into oxithiopurinol. More than 80% of the radioactivity of plasma was identified as oxithiopurinol less than 10 minutes after intravenous or oral administration. The parameters of oxithiopurinol were estimated from the decline of radioactivity in blood from 5 minutes to 8 hours after intravenous administration of 4 microCi/100 g of thiopurinol (8 animals) or oxithiopurinol (5 animals). Half lives of oxithiopurinol t 1/2 (beta) were 2.52 +/- 0.78 hr and 2.90 +/- 1.00 hr and clearance 2.00 +/- 0.36 ml/min. and 3.38 +/- 0.69 respectively. Estimate of renal clearance for oxithiopurinol in rat was 4,17 ml/min. The rapidity of hydroxylation and of elimination of oxithiopurinol might be assumed to be the cause of the apparent ineffectiveness of thiopurinol in vivo on xanthine oxidase activity.

Study of urinary pyrazinamide metabolites and their action on the renal excretion of xanthine and hypoxanthine in a xanthinuric patient.

A chromatographic technique on anion exchange column was developed. It permets to determine unmetabolized pyrazinamide and three major metabolities: pyrazinoic acid, 5-hydroxypyrazinoic acid and an unidentified compound. In a xanthinuric patient only traces of 5-hydroxypyrazinoic acid were found 12 hours after 3 g pyrazinamide were given. These finding confirms that pyrazinoic acid is oxidised through the the action of xanthine oxidase. Both the clearances of hypoxanthine and of xanthine are as rapid as that of endogenous creatinine in a xanthinuric patient. But the effects of pyrazinamide are different on both purine bases. Urinary excretion of hypoxanthine is slightly but not significantly reduced while excretion of xanthine is decreased by about 75%. Evidence was demonstrated that pyrazinoic acid is likely the agent causing xanthine retention. These results suggest that the mechanisms of renal transport of xanthine and hypoxanthine are different.

Xanthinuria : study of a large kindred with familial urolithiasis and gout.

We have carried out biochemical and clinical studies on a large family in which xanthinuria, xanthine lithiasis, uric acid lithiasis and/or gout were discovered. The analysis of its pedigree has shown that : a) the mode of transmission of xanthinuria is autosomal recessive; b) the occurence of xanthine urolithiasis is likely to be due to the association of a second genetic disorder.

[Inactivation by 4,6 disubstituted pyrazolo (3,4-d) pyrimidines of the arsenolysis of guanosine by erythrocyte purine nucleoside phosphorylase]. / Inactivation, par des pyrazolo [3,4-d] pyrimidines 4,6 disubstituées, de l'arsénolyse de la guanosine par la purine nucléoside phosphorylase érythrocytaire

New drugs are proposed in an attempt to reduce the overformation of uric acid in man. The procedure is based on the inhibition of human purine nucleoside phosphorylase selectively investigated in its phosphorolytic sequence. But for technical reasons, analogous inactivation of the enzyme in its comparative guanosine arsenolysis is subject to experimentation.

[Methods of isolation and determination of urinary 4-thio-6-hydroxypyrazolo(3,4 d)pyrimidine in patients treated with thiopurinol]. / Méthodes d'isolement et de détermination de la 4-thio-6-hydroxypyrazolo(3,4-d)pyrimidine urinaire chez les patients traités par le thiopurinol

Oxithiopurinol, [4-thio-6-hydroxypyrazolo(3,4-d)pyrimidine] has been caracterized in urines of patients treated with Thiopurinol : the principle involved is the precipitation of both oxithiopurinol and uric acid in combination with cupric hydroxide. The urinary oxithopurinol content is determined by means of anion and cation exchange resins. 56 to 70 per cent of the daily dose of Thiopurinol are eliminated in urine as oxithiopurinol.