Automated Determination of Uric Acid, with Use of a Uricase—Peroxidase System

Gochman, Nathan; Schmitz, Joan M.

doi:10.1093/clinchem/17.12.1154

Cited by 137 publications

(36 citation statements)

References 6 publications

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“…A Hitachi 917 autoanalyzer obtained from Roche Diagnostics (Mannheim, Germany) was used to measure uric acid and creatinine. Ascorbic acid is known to interfere with the measurement of uric acid by redox reaction–based colorimetric methods (4) or by uricase/peroxidase‐based methods (7). In our analysis, serum samples were initially incubated with a reagent mixture that contained ascorbate oxidase to remove ascorbic acid (≤1,703 μ moles/liter).…”

Section: Methodsmentioning

confidence: 99%

The effects of vitamin C supplementation on serum concentrations of uric acid: Results of a randomized controlled trial

Huang

Appel

Choi

et al. 2005

Arthritis & Rheumatism

176

106

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Objective. Reductions in serum uric acid levels are clinically relevant. Previous studies have suggested a uricosuric effect of vitamin C. Whether vitamin C reduces serum uric acid is unknown. We undertook this study to determine the effects of vitamin C supplementation on serum uric acid concentrations.Methods. The study was a double-blinded placebo-controlled randomized trial conducted in research units affiliated with an academic institution. Study participants were 184 nonsmokers, randomized to take either placebo or vitamin C supplements (500 mg/day) for 2 months.Results. At the end of the study period, serum uric acid levels were significantly reduced in the vitamin C group (mean change ؊0.5 mg/dl [95% confidence interval ؊0.6, ؊0.3]), but not in the placebo group (mean change 0.09 mg/dl [95% confidence interval ؊0.05, 0.2]) (P < 0.0001). The same pattern of results was evident in subgroups defined by age, sex, race, body mass index, chronic illness, diuretic use, and quartiles of baseline serum ascorbic acid levels. In the subgroups, from the lowest to the highest quartile of baseline serum uric acid, net mean changes (95% confidence intervals) in serum uric acid with vitamin C supplementation were ؊0.4 (؊0.8, 0.01), ؊0.5 (؊0.9, ؊0.2), ؊0.5 (؊0.8, ؊0.2), and ؊1.0 (؊1.6, ؊0.4) mg/dl (P ‫؍‬ 0.06, 0.005, 0.003, and 0.002, respectively). Compared with placebo, vitamin C increased the estimated glomerular filtration rate.Conclusion. Supplementation with 500 mg/day of vitamin C for 2 months reduces serum uric acid, suggesting that vitamin C might be beneficial in the prevention and management of gout and other uraterelated diseases.

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Section: Methodsmentioning

confidence: 99%

The effects of vitamin C supplementation on serum concentrations of uric acid: Results of a randomized controlled trial

Huang

Appel

Choi

et al. 2005

Arthritis & Rheumatism

176

106

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“…The SUA levels were assayed by the colorimetric uricase-peroxidase system. 25 All participants provided written informed consent authorizing the Taipei City Government to process the health examination data for research purposes. Detailed deidentified data were stored centrally in the Taipei City Elderly Health Examination Database, which was linked to the Taiwan National Death Registry System.…”

Section: Data Sourcementioning

confidence: 99%

U‐Shaped Association Between Serum Uric Acid Levels With Cardiovascular and All‐Cause Mortality in the Elderly: The Role of Malnourishment

Tseng

Chen

et al. 2018

JAHA

126

103

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BackgroundThe link between elevated serum uric acid (SUA) levels and cardiovascular disease (CVD)–related mortality in the elderly population remains inconclusive. Nutritional status influences both SUA and CVD outcomes. Therefore, we investigated whether SUA‐predicted mortality and the effect‐modifying roles of malnourishment in older people.Methods and ResultsA longitudinal Taiwanese cohort including 127 771 adults 65 years and older participating in the Taipei City Elderly Health Examination Program from 2001 to 2010 were stratified by 1‐mg/dL increment of SUA. Low SUA (<4 mg/dL) strata was categorized by malnourishment status defined as Geriatric Nutritional Risk Index <98, serum albumin <38 g/L, or body mass index <22 kg/m2. Study outcomes were all‐cause and CVD‐related mortality. Cox models were used to estimate hazard ratios (HRs) of mortality, after adjusting for 20 demographic and comorbid covariates. Over a median follow‐up of 5.8 years, there were 16 439 all‐cause and 3877 CVD‐related deaths. Compared with the reference SUA strata of 4 to <5 mg/dL, all‐cause mortality was significantly higher at SUA <4 mg/dL (HR, 1.16; 95% confidence interval, 1.07–1.25) and ≥8 mg/dL (HR, 1.13; confidence interval, 1.06–1.21), with progressively elevated risks at both extremes. Similarly, increasingly higher CVD‐related mortality was found at the SUA level <4 mg/dL (HR, 1.19; confidence interval, 1.00–1.40) and ≥7 mg/dL (HR, 1.17; confidence interval, 1.04–1.32). Remarkably, among the low SUA (<4 mg/dL) strata, only malnourished participants had greater all‐cause and CVD‐related mortality. This modifying effect of malnourishment remained consistent across subgroups.Conclusions SUA ≥8 or <4 mg/dL independently predicts higher all‐cause and CVD‐related mortality in the elderly, particularly in those with malnourishment.

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“…Serum glucose was measured using a glucose oxidase method. Serum uric acid was assayed by an automated method based upon the uricase-peroxidase system [27]. Cholesterol and triglycerides were measured by a fully automated enzymatic colorimetric method using commercially available reagents (Boehringer Mannheim).…”

Section: Biochemical Analysesmentioning

confidence: 99%

Antioxidant status in patients with uncomplicated insulin‐dependent and non‐insulin‐dependent diabetes mellitus

Maxwell

Thomason

Sandler³

et al. 1997

Eur J Clin Investigation

363

216

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Oxidative damage by free radicals has been implicated in the pathogenesis of vascular disease in diabetes. We compared the radical-scavenging antioxidant activity of serum from 28 patients with insulin-dependent diabetes mellitus and 24 patients with non-insulin-dependent diabetes mellitus uncomplicated by vascular disease with age-matched non-diabetic control subjects. Patients with insulin-dependent diabetes had significantly reduced total antioxidant activity (320.2 +/- 11.3 vs. 427.5 +/- 19.2 mumol L-1; P < 0.001). This was attributable to lower urate (209.4 +/- 10.4 vs. 297.1 +/- 16.7 mumol L-1; P < 0.001) and vitamin C levels (63.6 +/- 6.0 vs. 87.5 +/- 4.9 mumol L-1; P < 0.01). Patients with non-insulin-dependent diabetes had lower total antioxidant activity than age-matched control subjects (433.8 +/- 25.4 vs. 473.9 +/- 30.2 mumol L-1; NS), reflecting lower urate (299.5 +/- 19.4 vs. 324.8 +/- 21.4 mumol L-1; NS) and vitamin C levels (38.6 +/- 5.7 vs. 58.5 +/- 5.3 mumol L-1; P < 0.05). Multiple regression analysis showed that urate, vitamin C and vitamin E were the major contributors to serum total antioxidant activity. These results show that diabetic patients have significant defects of antioxidant protection, which may increase vulnerability to oxidative damage and the development of diabetic complications.

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Automated Determination of Uric Acid, with Use of a Uricase—Peroxidase System

Cited by 137 publications

References 6 publications

The effects of vitamin C supplementation on serum concentrations of uric acid: Results of a randomized controlled trial

The effects of vitamin C supplementation on serum concentrations of uric acid: Results of a randomized controlled trial

U‐Shaped Association Between Serum Uric Acid Levels With Cardiovascular and All‐Cause Mortality in the Elderly: The Role of Malnourishment

Antioxidant status in patients with uncomplicated insulin‐dependent and non‐insulin‐dependent diabetes mellitus

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