Two Ultramicro-Scale Methods for Plasma Uric Acid Analysis with Uricase

1974 ◽  
Vol 20 (7) ◽  
pp. 790-793 ◽  
Author(s):  
Samuel Meites ◽  
Carlotta Thompson ◽  
Ralph W Roach
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Crystal Violet ◽  
Gentian Violet ◽  
Plasma Concentrations ◽  
Polarographic Method ◽  
Advantages And Disadvantages ◽  
Sensing System ◽  
Plasma Uric Acid ◽  
Manual Analysis

Abstract Results with two ultramicro methods for plasma uric acid analysis with uricase are described: a crystal violet (gentian violet) method, modified from an automated procedure by Gochman and Schmitz [Clin. Chem. 17, 1154 (1971)] and adapted to manual analysis, and a polarographic oxygen-sensing system (Beckman Instruments, Inc.). The coefficient of variation (CV) for the crystal violet method varied between 2.1 and 5.7% for an 11-month period. Within-run precision (CV) of the polarographic method was 3.3%; day-to-day CV varied between 3.4 and 9.4%. Percentage recovery for the crystal violet method ranged between 97 and 106%, and for the polarographic method between 92 and 100%. Results of the two methods correlate well, but 5-15% lower values are obtained by the crystal violet method than by the polarographic method. Bilirubin, hemolysis, or usual plasma concentrations of ascorbic acid do not interfere significantly with either method. Advantages and disadvantages of both methods are discussed. The polarographic method requires more uricase, but is the better of the two methods.

Estimate of antioxidant capacity and lipid peroxidation in plasma of healthy subjects

Open Medicine ◽  
2006 ◽  
Vol 1 (1) ◽  
pp. 23-34
Author(s):  
Anna Gorąca ◽  
Beata Skibska
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Plasma Concentrations ◽  
Beta Carotene ◽  
Alpha Tocopherol ◽  
Elderly Subjects ◽  
Total Antioxidant

AbstractSerum contains various antioxidant molecules that may provide important protection against free radical attack. The aim of this work was to assess the total antioxidant capacity of plasma and a marker of lipid per oxidation [(thiobarbituric acid-reactive substances (TBARS)] in plasma of healthy smoking and non-smoking young and elderly subjects. In addition, we investigated plasma concentrations of α-tocopherol, β-carotene, and ascorbic acid. In in vitro experiments, the effects of exogenous compounds (ascorbic acid, uric acid, Trolox) on total ferric-reducing activity of plasma (FRAP) were also tested. We demonstrated that total antioxidant capacity of plasma obtained from healthy non-smoking young subjects was significantly higher than plasma antioxidant capacity of smoking elderly subjects. The concentration of TBARS in young non-smoking volunteers was lower than that in young smokers. The concentration of TBARS in elderly non-smoking volunteers was lower than in elderly smokers. Plasma concentrations of alpha-tocopherol, beta-carotene and ascorbic acid were significantly lower in elderly smoker than in elderly non-smokers of the same age. No difference in the plasma levels of alpha-tocopherol, beta-carotene and ascorbic acid were found in 22-year-old smoking and non-smoking subjects. In vitro addition of ascorbic acid, uric acid, or Trolox to plasma samples significantly increased their total antioxidant capacity. Decrease of FRAP values and increase of TBARS concentrations is a significant physiologic condition of the aging process. Supplementation of antioxidants could be useful for the enhancement of antioxidant screen in plasma.

scholarly journals Effect of vitamin A deficiency on protein catabolism in chicks

1974 ◽  
Vol 31 (1) ◽  
pp. 1-11 ◽  
Author(s):  
I. Bruckental ◽  
I. Ascarelli ◽  
A. Bondi
Keyword(s):  
Uric Acid ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Plasma Concentrations ◽  
Retinyl Palmitate ◽  
Acid Oxidase ◽  
Complete Disappearance ◽  
Amino Acid Oxidase ◽  
Plasma Urea ◽  
Plasma Uric Acid

1. The changes in the concentration of some enzymes and their metabolites were studied in the first stages of vitamin A deficiency in chicks.2. Kidney arginase (EC3.5.3.1) and liver xanthine dehydrogenase activities had increased even before complete disappearance of vitamin A from the plasma. Similarly, an increase was found in plasma uric acid, and plasma urea also increased but to a lesser extent. Liver proteolytic activity also was slightly increased by vitamin A deficiency.3. Kidney D-amino acid oxidase (EC1.4.3.3) activity and plasma concentrations of total protein and free amino acids were not affected, at least in the first stages of the deficiency.4. Oral dosing of deficient chicks with retinyl palmitate to provide 300 μg retinol, 24 h before killing, brought about a decrease in the activities of both enzymes and of plasma uric acid, and an increase in plasma urea.5. Dietary levels of vitamin A were reflected not only in the liver concentrations of the vitamin but also in the plasma concentrations.

Interference of levodopa and its metabolites with colorimetry of uric acid.

1981 ◽  
Vol 27 (5) ◽  
pp. 756-758 ◽  
Author(s):  
D W Bierer ◽  
A J Quebbemann
Keyword(s):  
Uric Acid ◽  
Acid Concentration ◽  
Peak Plasma ◽  
Plasma Concentrations ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Uric Acid Concentration ◽  
Chemical Mechanisms ◽  
Plasma Uric Acid ◽  
Hydroxyphenylacetic Acid

Abstract Reportedly, levodopa (L-DOPA) administration produces spuriously high values for plasma uric acid as measured by the commonly used phosphotungstic acid-hydroxylamine colorimetric method. We confirm this interference, not only by L-DOPA but also by three of its major metabolites: dopamine, 3,4-dihydroxyphenylacetic acid, and 3-methoxy-4-hydroxyphenylacetic acid. However, at therapeutic concentrations in plasma (less than 5 mg/L), the maximum spurious uric acid concentration due to L-DOPA is less than 2 mg/L. Also, at reported peak plasma concentrations of L-DOPA plus three of its major metabolites, the maximum spurious uric acid concentration due to all four compounds combined is less than 8.5 mg/L. Therefore, the hyperuricemia observed with this method in some patients who are chronically receiving L-DOPA cannot be attributed only to interference by L-DOPA and its metabolites in the colorimetric determination of uric acid. Evidently L-DOPA may increase laboratory values for plasma uric acid concentrations, both by pharmacological and chemical mechanisms.

scholarly journals Plasma Uric Acid and the Risk of Type 2 Diabetes in a Chinese Community

2008 ◽  
Vol 54 (2) ◽  
pp. 310-316 ◽  
Author(s):  
Kuo-Liong Chien ◽  
Ming-Fong Chen ◽  
Hsiu-Ching Hsu ◽  
Wei-Tien Chang ◽  
Ta-Chen Su ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Uric Acid ◽  
Cohort Study ◽  
Plasma Concentrations ◽  
Uric Acid Concentration ◽  
Cross Sectional ◽  
Plasma Uric Acid ◽  
The Metabolic Syndrome

Abstract Background: Previous cross-sectional studies have shown hyperuricemia to be prevalent among individuals with metabolic syndrome, but the evidence from prospective studies of an association between uric acid and diabetes risk is limited. We prospectively investigated the association between plasma concentrations of uric acid and the incidence of type 2 diabetes in Chinese individuals. Methods: We conducted a community-based prospective cohort study of 2690 participants (age range, 35–97 years) in the Chin-Shan Community Cardiovascular Cohort Study, who were found to be free of diabetes and cardiovascular disease during baseline assessment at study entry in 1990. During a median 9.0-year follow-up, 548 participants developed type 2 diabetes. Results: High plasma uric acid concentrations were associated with a higher prevalence of metabolic syndrome. After adjustment for age, sex, body mass index, and other covariates, the relative risks (RR) of diabetes according to uric acid quintile were 1.11, 1.29, 1.40, and 1.63 [95% confidence interval (CI), 1.20–2.23; P for trend <0.001]. After additional adjustment for metabolic syndrome, the RR for comparing the participants in the fifth and first uric acid quintiles was 1.40 (95% CI, 1.02–1.92; P for trend = 0.027). In joint analyses, participants who were in the highest uric acid quintile and also had metabolic syndrome had a 3.3-fold greater risk of diabetes (95% CI, 2.27–4.94) than those in the lowest uric acid quintile and without metabolic syndrome. Conclusions: These findings suggest a modest positive association between plasma uric acid concentration and the incidence of type 2 diabetes in Chinese individuals. The association between hyperuricemia and diabetes was partly mediated through the metabolic syndrome.

scholarly journals Caffeine improves biochemical and specific performance after judo training: a double-blind crossover study in a real judo training situation

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Kelvin Euton Oliveira Carmo ◽  
Diego Ignácio Valenzuela Pérez ◽  
Charles Nardelli Valido ◽  
Jymmys Lopes dos Santos ◽  
Bianca Miarka ◽  
...  
Keyword(s):  
Heart Rate ◽  
Uric Acid ◽  
Body Mass ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Power Performance ◽  
Double Blind ◽  
Biochemical Effect ◽  
Plasma Uric Acid ◽  
Hemodynamic Variables

Abstract Background Nutritional ergogenic aids are foods or nutrients that can improve physical performance. Among these foods with ergogenic properties, caffeine has shown that it can increase the fat catabolism, strength, and improve the cognition and time reaction of an athlete, therefore, it is hoped that it can improve the performance of judokas. This study through a double-blind crossover (supplement X placebo) protocol, investigated the effects caffeine supplementation (single capsule containing 5 mg/kg body mass intake 60 min before the session) on biochemical, anthropometrical, physical, subjective and hemodynamic variables measured before, during and after two typical judo trainingcxs sessions (120-min: 40-min of gymnastics; 40-min of specific technics and; 40-min of judo combat). Methods 8 high-level athletes (21.4 ± 2.0 years; 83.6 ± 15.2 kg; 1.8 ± 0.1 m; 17.9 ± 7.0 Fat%) were evaluated before and after each training for body mass, hydration, upper and lower limb power, performance in the special judo fitness test (SJFT), free fatty acids (FFA) in plasma, uric acid, glucose, lactate, heart rate, and pain. In addition, heart rate, FFA in plasma, uric acid, glucose, lactate, rating of perceived exertion and pain were assessed during the training. Results At 120 min, supplementation resulted in a higher concentration of plasma FFA (1.5 ± 0.5 vs. 1.0 ± 0.3 mmol/L; p = 0.047) and lactate (4.9 ± 1.8 vs. 3.0 ± 1.2 mmol/L; p = 0.047), and a lower concentration of uric acid (5.4 ± 0.9 vs. 7.0 ± 1.5 mg/dL; p = 0.04). Supplementation also resulted in performance maintenance (fatigue index) in the SJFT (Δ0.3 ± 2.0 vs Δ1.7 ± 2.5, for caffeine and placebo respectively, p = 0.046). No adverse effects were observed. Conclusion Based on the applied dose, intake time, and sample of this study, we can conclude that caffeine produces an ergogenic biochemical effect, and improves performance in judo athletes.

scholarly journals Vitamin C—Sources, Physiological Role, Kinetics, Deficiency, Use, Toxicity, and Determination

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 615
Author(s):  
Martin Doseděl ◽  
Eduard Jirkovský ◽  
Kateřina Macáková ◽  
Lenka Krčmová ◽  
Lenka Javorská ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Iron Absorption ◽  
Plasma Concentrations ◽  
Physiological Role ◽  
Renal Stones ◽  
Anti Oxidant ◽  
High Doses ◽  
Epigenetic Processes

Vitamin C (L-ascorbic acid) has been known as an antioxidant for most people. However, its physiological role is much larger and encompasses very different processes ranging from facilitation of iron absorption through involvement in hormones and carnitine synthesis for important roles in epigenetic processes. Contrarily, high doses act as a pro-oxidant than an anti-oxidant. This may also be the reason why plasma levels are meticulously regulated on the level of absorption and excretion in the kidney. Interestingly, most cells contain vitamin C in millimolar concentrations, which is much higher than its plasma concentrations, and compared to other vitamins. The role of vitamin C is well demonstrated by miscellaneous symptoms of its absence—scurvy. The only clinically well-documented indication for vitamin C is scurvy. The effects of vitamin C administration on cancer, cardiovascular diseases, and infections are rather minor or even debatable in the general population. Vitamin C is relatively safe, but caution should be given to the administration of high doses, which can cause overt side effects in some susceptible patients (e.g., oxalate renal stones). Lastly, analytical methods for its determination with advantages and pitfalls are also discussed in this review.

scholarly journals Interference of ascorbic acid with chemical analytes

2005 ◽  
Vol 42 (6) ◽  
pp. 475-477 ◽  
Author(s):  
Qing H Meng ◽  
William C Irwin ◽  
Jennifer Fesser ◽  
K Lorne Massey
Keyword(s):  
Ascorbic Acid ◽  
Creatine Kinase ◽  
Uric Acid ◽  
Total Cholesterol ◽  
Acid Concentration ◽  
Total Bilirubin ◽  
Binding Capacity ◽  
Ascorbic Acid Concentration ◽  
Sodium Potassium ◽  
Creatine Kinase Mb

Background: Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20®. Methods: Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20. Results: With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively ( P<0.01). With a serum ascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively ( P<0.01), and were undetectable for total cholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO2, urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium. Conclusions: Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.

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