Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018099 (gout)
 5,192 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A simple inexpensive method is described for determining plasma uric acid levels in companion birds. Plasma uric acid concentrations in 33 healthy parakeets were determined by a modification of the uricase spectrophotometric procedure utilizing 50 microliters of plasma. The mean uric acid level in parakeets was 5.60 mg/dl blood plasma, with no significant difference between males and females. In White Leghorn chickens, however, the mean level of uric acid in plasma was 7.19 mg/dl in males and 3.05 mg/dl in females. This method may be useful for the diagnosis and study of gout in small birds.
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PMID:A micromethod for plasma uric acid determinations in companion birds. 52 10

Polyethylene glycol-modified urate oxidase (PEG-uricase) holds promise as a hypouricemic agent for treating gout and as an adjunct to cytolytic therapy of hematologic malignancies. Spectrophotometric assays of urate oxidase are not sensitive enough for pharmacokinetic evaluation of PEG-uricase in clinical trials. We have therefore developed a more sensitive radiochemical-HPLC assay for urate oxidase activity in untreated plasma, in which 14C in urate and in the reaction product, allantoin, is monitored in the uv detector effluent with a flow-through scintillation counter. The assay is linear with amount of enzyme and time of incubation and can detect less than 1 x 10(-5) U/ml uricase in plasma. The assay accounts for plasma samples of widely differing urate content.
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PMID:A radiochemical-high-performance liquid chromatographic assay for urate oxidase in human plasma. 274 21

Uric acid concentration in the serum was investigated 3 times a day using the uricase method in 15 gout inpatients on a hypopurine diet with age- and sex-adjusted caloric content. The highest uric acid concentration was noted at 7 a. m., the lowest concentration value at 11 p. m. The highest renal clearance values were noted from 7 a. m. till 3 p. m., the lowest ones from 11 p. m. till 7 a. m. Similar regularities were noted in 15 rheumatoid arthritic patients, however uric acid concentration in the serum was lower and its renal excretion was 1.7 times more effective.
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PMID:[Circadian rhythm of uric acid levels of the serum in gout]. 358 98

Urate oxidase, or uricase (EC 1.7.3.3), is a purine metabolic enzyme that catalyzes the conversion of uric acid to allantoin in most mammals except humans and certain other primates. The loss of urate oxidase in the human during primate evolution predisposes man to hyperuricemia, a metabolic disturbance that can lead to gouty arthritis and renal stones. To create a mouse model for hyperuricemia and gout, and to address the question of whether urate oxidase is essential in lower mammalian species, we have disrupted the urate oxidase gene in the mouse by homologous recombination in embryonic stem cells. Unlike the human situation, urate oxidase deficiency in mice causes pronounced hyperuricemia and urate nephropathy. More than half of the mutant mice died before 4 weeks of age, indicating that urate oxidase is essential in mice. These mutant mice may also serve as animal models for hyperuricemia and its related nephropathy in humans.
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PMID:Hyperuricemia and urate nephropathy in urate oxidase-deficient mice. 829 May 93

Uric acid in blood has been widely accepted as a reliable indicator of hyperuricemia and gout, and its assay method has been established. In the present study, we developed a simple and non-invasive rapid method for the determination of uric acid in hair. Concentration(nmol/mg hair) of uric acid extracted from 10-20 mg of hair(95% < extractability; 0.1N KOH, 37 degrees C, 2 hr) was determined by an enzymatic method using uricase. The concentration of uric acid(nmol/mg hair, mean +/- SD: 0.489 +/- 0.157, n = 16) in hair from hyperuricemic patients was significantly higher than that(0.258 +/- 0.107, n = 8) from healthy volunteers(p < 0.01). Within-run and between-day precisions(reproducibilities, CVs) for the assay were 9.6-10.3%(n = 10 each) and 11.6-16.3%(n = 7 each), respectively. The concentration(y, nmol/mg hair) of uric acid in hair correlated well with that in blood(x, g/l): y = 8.770x-0.123(r = 0.746, Syx = 0.122, n = 23). Changes in the concentration of uric acid in hair of hyperuricemic patient treated with allopurinol paralleled to those in blood. In conclusion, it was confirmed that the concentration of uric acid in hair reflected that in blood, suggesting that measuring uric acid in hair can be available for the metabolic control in hyperuricemia.
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PMID:[Determination of uric acid in scalp hair for non-invasive estimation of uricemic control in hyperuricemia]. 939 46

The uric acid concentration in blood has been widely accepted as a diagnostic indicator of hyperuricemia and gout, and its assay method is well established. In the present study, we developed a simple and rapid method for the determination of uric acid in hair, which can be obtained non-invasively. The concentration (nmol/mg hair) of uric acid extracted from 10-20 mg hair with 0.1 M potassium hydroxide was determined by an enzymatic method using uricase. The concentration of uric acid (nmol/mg hair, mean+/-S.D.: 0.49+/-0.157, n=16) in hair from hyperuricemic patients was significantly higher than that (0.26+/-0.107, n=8) in healthy volunteers (p<0.01). The within-run and between-day precision (CVs) of the assay was 9.6-10.3% (n=10 each) and 11.6-16.3% (n=7 each), respectively. The concentration (nmol/mg hair, y) of uric acid in hair correlated well with that in serum (mg/l, x): y=0.09x-0.12 (r=0.75, Syx=0.122, n=23). Changes in the concentration of uric acid in the hair of antihyperuricemic drug-treated patient paralleled that in serum, suggesting that the concentration of uric acid in hair is a reliable indicator of the metabolic control in hyperuricemia.
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PMID:Determination of uric acid in scalp hair for non-invasive evaluation of uricemic controls in hyperuricemia. 958 80

A major obstacle to the treatment of hyperuricemia in patients allergic to allopurinol is the limited availability of suitable, equally effective, alternative, urate-lowering drugs. Conventional uricosuric drugs, including probenecid and sulfinpyrazone, are recommended for allopurinol- intolerant patients with gout and "underexcretion" hyperuricemia who have normal renal function and no history of nephrolithiasis. Therapeutic options in those in whom traditional uricosuric drugs are contraindicated, ineffective, or poorly tolerated include slow oral desensitization to allopurinol and cautious administration of oxipurinol. Allopurinol desensitization is useful particularly in those who have failed other treatment modalities. If available (as in Europe, South Africa, and Japan), benzbromarone may be tried in patients with gout and mild-to-moderate renal insufficiency. Recombinant urate oxidase can be used in the short-term prophylaxis and treatment of chemotherapy- associated hyperuricemia in patients with lymphoproliferative and myeloproliferative disorders. Hyperuricemia and gout occur with increased frequency in cyclosporine-treated allograft transplant recipients. The management of gout in these patients is complicated by two main factors: cyclosporine-induced renal impairment, and interactions with medications used to preserve the allograft.
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PMID:Difficult gout and new approaches for control of hyperuricemia in the allopurinol-allergic patient. 1117 68

Uricase-deficient mice develop uric acid nephropathy, with high mortality rates before weaning. Urate excretion was quantitated and renal function was better defined in this study, to facilitate the use of these mice as a model for evaluating poly(ethylene glycol)-modified recombinant mammalian uricases (PEG-uricase) as a potential therapy for gout and uric acid nephropathy. The uric acid/creatinine ratio in the urine of uricase-deficient mice ranges from 10 to >30; on a weight basis, these mice excrete 20- to 40-fold more urate than do human subjects. These mice consistently develop a severe defect in renal concentrating ability, resulting in an approximately sixfold greater urine volume and a fivefold greater fluid requirement, compared with normal mice. This nephrogenic diabetes insipidus leads to dehydration and death of nursing mice but, with adequate water replacement, high urine flow protects adults from progressive renal damage. Treatment of uricase-deficient mice with PEG-uricase markedly reduced urate levels and, when initiated before weaning, preserved the renal architecture (as evaluated by magnetic resonance micros-copy) and prevented the loss of renal concentrating function. PEG-uricase was far more effective and less immunogenic than unmodified uricase. Retention of uricase in most mammals and its loss in humans and some other primates may reflect the evolution of renal function under different environmental conditions. PEG-uricase could provide an effective therapy for uric acid nephropathy and refractory gout in human patients.
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PMID:Diabetes insipidus in uricase-deficient mice: a model for evaluating therapy with poly(ethylene glycol)-modified uricase. 1131 59

Uric acid (UA) is a purine metabolite that selectively inhibits peroxynitrite-mediated reactions implicated in the pathogenesis of multiple sclerosis (MS) and other neurodegenerative diseases. Serum UA levels are inversely associated with the incidence of MS in humans because MS patients have low serum UA levels and individuals with hyperuricemia (gout) rarely develop the disease. Moreover, the administration of UA is therapeutic in experimental allergic encephalomyelitis (EAE), an animal model of MS. Thus, raising serum UA levels in MS patients, by oral administration of a UA precursor such as inosine, may have therapeutic value. We have assessed the effects of inosine, as well as inosinic acid, on parameters relevant to the chemical reactivity of peroxynitrite and the pathogenesis of EAE. Both had no effect on chemical reactions associated with peroxynitrite, such as tyrosine nitration, or on the activation of inflammatory cells in vitro. Moreover, when mice treated with the urate oxidase inhibitor potassium oxonate were fed inosine or inosinic acid, serum UA levels were elevated markedly for a period of hours, whereas only a minor, transient increase in serum inosine was detected. Administration of inosinic acid suppressed the appearance of clinical signs of EAE and promoted recovery from ongoing disease. The therapeutic effect on animals with active EAE was associated with increased UA, but not inosine, levels in CNS tissue. We, therefore, conclude that the mode of action of inosine and inosinic acid in EAE is via their metabolism to UA.
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PMID:Therapeutic intervention in experimental allergic encephalomyelitis by administration of uric acid precursors. 1245 Nov 83

Urate, a purine metabolite, is a cause of gout(hyperuricemia), which is an independent risk factor for cardiovascular disease. Urate is a scavenger of reactive oxygen radicals that are involved in numerous diseases. Because humans have a renal urate reabsorption system and have lost hepatic uricase by mutational silencing in evolution, urate is present in human blood at high levels. We identified the long-hypothesized urate transporter in the human kidney (URAT1, encoded by SLC22A12), a urate anion exchanger regulating blood urate levels and targeted it with uricosuric and antiuricosuric agents. Moreover, we demonstrated that patients with renal hypouricemia have mutational defects in SLC22A12.
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PMID:[Urate transporter and renal hypouricemia]. 1456 Jun 59


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