PubMed · 7022586
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
G Berni, A Lagi, C Francois. 1981. [Urate nephropathy].. https://pubmed.ncbi.nlm.nih.gov/7022586/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
BACKGROUND: The myocardial protective role of heat shock protein (HSP) has been demonstrated. Recently, we reported that ischemia/reperfusion induced a significant activation of heat shock factor (HSF) 1 and an accumulation of mRNA for HSP70 and HSP90. We examined the role of reactive oxygen species (ROSs) in the induction of stress response in the ischemic-reperfused heart. METHODS AND RESULTS: Rat hearts were isolated and perfused with Krebs-Henseleit buffer by the Langendorff method. Whole-cell extracts were prepared for gel mobility shift assay using oligonucleotides containing the heat shock element. Induction of mRNA for HSP70 and HSP90 was examined by Northern blot analysis. Repetitive ischemia/reperfusion, which causes recurrent bursts of free radical generation, resulted in burst activation of HSF1, and this burst activation was significantly reduced with either allopurinol 1 mmol/L (an inhibitor of xanthine oxidase) or catalase 2x10(5) U/L (a scavenger of H2O2). Significant activation of HSF1 was observed on perfusion with buffer containing H2O2 150 micromol/L or xanthine 1 mmol/L plus xanthine oxidase 5 U/L. The accumulation of mRNA for HSP70 or HSP90 after repetitive ischemia/reperfusion was reduced with either allopurinol or catalase. CONCLUSIONS: Our findings demonstrate that ROSs play an important role in the activation of HSF1 and the accumulation of mRNA for HSP70 and HSP90 in the ischemic-reperfused heart.
OBJECTIVES: To evaluate the in vivo effect of xanthine oxidase (XO) inhibition by allopurinol on the determination of polymorphic N-acetyltransferase 2 (NAT2) and cytochrome P450 1A2 (CYP1A2) with urinary caffeine metabolic ratios. METHODS: In an open, prospective study involving 21 healthy subjects (eight fast, 13 slow NAT2 acetylators) allopurinol (300 mg perday) was administered orally on trial days 1-8, followed by a wash-out period of 8 days. Urinary caffeine tests (200 mg caffeine p.o.) were performed repetitively. Urine was collected for 8 h and venous blood samples for the determination of allopurinol, oxypurinol and uric acid were drawn. The urinary caffeine metabolites 1-methyluric acid (1MU), 1-methylxanthine (1MX), 1,7-dimethyluric acid (17MU), 1,7-dimethylxanthine (17MX), 5-acetylamino-6-formylamino-3-methyluracil (AFMU), plasma allopurinol and oxypurinol were analysed using high-performance liquid chromatography (HPLC). RESULTS: During XO inhibition by allopurinol, the formation of 1MU from 1MX and therefore the XO ratio 1MU/1MX decreased to 15.9 (1.2)% [mean with (SEM)] of baseline values (P < 0.005). The NAT2 ratio AFMU/1MX decreased likewise to 56.7 (6.3)% (P < 0.005). AFMU/(AFMU + 1MX + 1MU), an alternative NAT2 ratio, remained constant, but the CYP1A2 ratio (AFMU + 1MX + 1MU)/17MU, used to express CYP1A2 activity, transiently increased to 167 (13)% (P < 0.005). The NAT2 phenotype did not influence CYP1A2 and XO ratios or plasma oxypurinol pharmacokinetics. CONCLUSIONS: Several caffeine metabolic ratios are commonly used to express the activities of NAT2, CYP1A2 and XO both in healthy volunteers and in polymedicated patients, although their reliability has not been evaluated thoroughly during concurrent drug administration. The findings of this study suggest that NAT2 phenotyping should be performed using the ratio AFMU/(AFMU + 1MX + 1MU) if an XO inhibitor may be present. It also shows that the determination of CYP1A2 activity with caffeine as a metabolic probe is considerably altered under these conditions. Thus, concomitant drug administration may impair the robustness of multiple pathways of the complex caffeine test. This points to the need for alternative probes, designed to assess only the activity of a single enzyme because, in contrast to healthy volunteers, in patients known or unknown drug interactions may often be present.
The aim of this study was to determine whether allopurinol (ALLO) reduces reperfusion injury inflicted upon the heart resulting from excess production of free oxygen radicals after hypoxia and ischemia (HI) in newborn animals. We, therefore, produced severe HI in 13 newborn lambs by low O2-ventilation and blood volume reduction. One hour before HI seven lambs received ALLO (20 mg/kg i.v.), six received a placebo (CONT). Cardiac function and hemodynamic parameters were assessed by sequential measurement of left ventricular (LV) contractility through the end-systolic pressure-volume relation (ESPVR) using the conductance catheter method. Stroke volume (SV), cardiac output (CO), and aortic pressure (Pao) were measured and ejection fraction and total peripheral resistance (TPR) were calculated before HI, upon resuscitation (UR), and at 60 and 120 min post-HI. To estimate the effect of ALLO on redox status and anti-oxidative capacity, we measured concentrations of uric acid, sulfhydryl (SH), malondialdehyde (MDA), ascorbic acid (AA), and dehydroxylated ascorbic acid (DHAA) in plasma obtained from the coronary sinus and calculated the AA/DHAA ratio. Compared to CONT lambs, TPR in ALLO treated lambs decreased significantly, accompanied by a rise in CO and SV. ALLO did not affect myocardial contractility, because the ESPVR showed no significant differences between groups. AA/DHAA and SH showed a significant decrease in ALLO animals vs pre-HI, but not in CONT animals. Uric acid was significantly decreased in ALLO as compared to pre-HI and CONT animals. MDA was significantly increased in CONT animals at 15 min post-HI as compared to pre-HI, whereas in ALLO animals MDA showed a significant increase at 120 min post-HI vs CONT. We conclude that pretreatment with ALLO has a beneficial effect on the pump function by afterload reduction but not by changes in contractility. Furthermore, ALLO inhibited uric acid formation with a consequent decrease in anti-oxidative capacity.