Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “URIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed1977

In vitro photodecomposition of uric acid in presence of riboflavin II.

In vitro studies on the photodecomposition of uric acid in the presence of the monosodium salt of riboflavin 5'-phosphate in buffers at various pH values, in methanol, and in human plasma are reported. The decomposition rate increased with increasing pH and was independent of solvent or buffer species. The mechanism appears to be an energy transfer process involving triplet riboflavin and single oxygen. Riboflavin-enhanced photodecomposition of uric acid occurred in vitro in hyperuricemic human plasma.

Chromatography, High Pressure Liquid↗
PubMed1975

Enzymatic degradation of uric acid by uricase-loaded human erythrocytes.

Erythrocytes containing pig liver uricase have been prepared by hypotonic hemolysis in the presence of the enzyme. Uricase is shown to be active within the erythrocytes and to degrade uric acid as rapidly as it enters the cells when high intracellular enzyme concentrations are employed. The kinetics and characteristics of uric acid entry are shown to be the same for hemolysed and normal erythrocytes. At physiological concentrations of uric acid, loaded erythrocytes can degrade a maximum of about 21 mumol uric acid/liter erythrocytes per min. The possible application of enzyme-loaded erythrocytes to medicine is discussed.

Biological Transport↗
PubMed1980

Factor VIII related antigen/coagulant activity ratio as a predictor of fetal growth retardation: a comparison with hormone and uric acid measurements.

Factor VIII related antigen (VIIIRAg), Factor VIII coagulant activity (VIIIC), plasma uric acid, total plasma oestriol, plasma human placental lactogen (hPL) and urine oestrogen/creatinine ratio were measured in a group of 21 patients clinically suspected of fetal growth retardation and compared with normal pregnancy. Of the hormone assays, hPL was better than either oestrial or oestrogen/creatinine ratio at distinguishing between normal and growth retarded pregnancies. Uric acid levels tended to be higher than normal in patients with fetal growth retardation, but the best means of distinguishing normal from growth retarded pregnancies proved to be the VIIIRAg/VIIIC ratio. This ratio was significantly elevated in fetal growth retardation compared with normal pregnancy, and the increase was evident as early as 30 weeks gestation. Using the VIIIRAg/VIIIC ratio test, the outcome of 17 of the 21 suspect pregnancies could be correctly predicted.

Antigens↗
PubMed1975

Estimation of serum uric acid by high performance liquid chromatography with electrochemical detection.

A precise method for serum uric acid is described based on direct electrochemical oxidation in the eluate from high performance liquid chromatography. The detection limit for uric acid was found to be approximately 1 pg and accurate measurements were possible at the 100 pg level. Detailed procedures are outlined for 0.5 ml and 25 mul serum samples, the relative standard deviations being 1.7% and 1.8%, respectively, for a 6.2 ml/dl serum pool. Samples were normally deproteinized, however, the analysis can be carried out by injection of 2 mul of serum diluted 10-fold with distilled water. The proposed micro method is highly selective and eliminates the need for the enzyme preparation and/or nonspecific colorimetric reagents in common use.

Autoanalysis↗
PubMed2000

Uric acid and serum antioxidant capacity: a reaction to atherosclerosis?

BACKGROUND: the evidence of a potential beneficial role of antioxidants in preventing atherosclerotic disease is not entirely consistent. OBJECTIVE: to assess the longitudinal association of serum total antioxidant capacity and serum antioxidants with the presence of subclinical carotid atherosclerosis. METHODS: Prospective case-control study nested within an historical cohort. Cases were 150 individuals with elevated carotid intimal-medial thickness measured by B-mode ultrasound at the first two examinations of the Atherosclerosis Risk in Communities Study (1987-92). Controls were 150 age-gender-matched individuals with low carotid intimal-medial thickness. Serum antioxidant vitamins, uric acid, and serum total antioxidant capacity were measured in frozen serum samples collected from the same individuals in 1974 (13-15 years prior to the determination of case-control status). RESULTS: Compared to controls, atherosclerosis cases had significantly higher levels of serum total antioxidant capacity in 1974 than controls. This difference was almost entirely explained by increased serum concentration of uric acid in cases. In contrast with cross-sectional results, uric acid serum concentration in 1974, was significantly higher in cases than in controls, even after adjusting for the main cardiovascular risk factors. Cases had significantly lower levels of alpha-carotene in the 1974 sera than controls, but no other differences in serum antioxidant vitamin concentrations were observed. CONCLUSIONS: The higher serum uric acid concentration seemed associated with elevated total serum antioxidant capacity among individuals with atherosclerosis. This finding is consistent with experimental evidence suggesting that hyperuricemia may be a compensatory mechanism to counteract oxidative damage related to atherosclerosis and aging in humans.

Antioxidants↗
PubMed2004

Electrochemical determination of 8-oxoguanine in the presence of uric acid.

The electrochemical oxidation of 8-oxoguanine (8-oxoG) in the presence of uric acid (UA) was studied by differential pulse voltammetry over a wide pH range (1-12). The results showed that both compounds follow a pH-dependent oxidation mechanism that involves two electrons and two protons corresponding to reversible charge transfer reactions. The difference between the peak potential for the oxidation of each analyte was found to be always less than 100 mV over the whole pH range, the separation being greater in the pH interval 4-7. In mixtures of both analytes, pH 6 was shown to be the best for 8-oxoG determination in the presence of uric acid, since the peak current is higher and a greater peak separation is achieved.

Complex Mixtures↗
PubMed1991

Serum uric acid and its relation to cardiovascular disease risk factors in children and young adults from a biracial community: the Bogalusa Heart Study.

The distribution of serum uric acid and its relationship with cardiovascular risk variables have been studied in 3983 children and young adults, aged 5 to 26 years, drawn from a biracial (black and white) population. For two age groups, 5 to 11 years and 19 to 26 years, white subjects had significantly higher uric acid levels than black subjects, (4.02 mg/dl vs 3.57 mg/dl, p less than 0.0001, and 5.50 mg/dl vs 5.18 mg/dl, p less than 0.0001, respectively). Men in the 19 to 26 years age group had a significantly higher uric acid level than women (6.49 mg/dl vs 4.20 mg/dl, p less than 0.0001). White children and young adults were twice as likely to have levels above clinical limits than blacks, and males more likely to have hyperuricemia than females. Parents with a history of myocardial infarction were more likely to have children with hyperuricemia. Children and young adults with hyperuricemia had significantly higher plasma glucose (p less than 0.01) and insulin (p less than 0.001) levels, total cholesterol level (p less than 0.05), and serum triglyceride (p less than 0.0001), very-low-density lipoprotein cholesterol (p less than 0.01), low-density lipoprotein cholesterol (p less than 0.001), and total protein (p less than 0.0001) levels than subjects without hyperuricemia; high-density lipoprotein cholesterol level was significantly lower (p less than 0.0001) in subjects with hyperuricemia than in those without it.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Uric acid and chronic musculoskeletal complaints.

The relation between chronic musculoskeletal complaints and serum uric acid was examined in 737 men and 771 women (40-42 years old). The study is cross-sectional and part of the National Health Screening Service county studies in Norway. Both men and women with chronic musculoskeletal complaints had significantly higher s-urate means than persons without such complaints. Moreover, the prevalence of chronic musculoskeletal complaints (gout excluded) changed significantly across increasing s-urate levels also within the normal distribution of s-urate. Multivariate logistic regression analysis showed that the s-urate odds ratio for chronic complaints rose in a linear manner across these s-urate levels (adjusted for 12 other independent variables that may interfere with uric acid). Such a relation has not to our knowledge been previously described.

Adult↗
PubMed1979

Hyperxanthinemia interferes with serum uric acid determinations by the uricase method.

Serum xanthine concentrations as high as 148 mg/L were noted after treatment of a patient with Burkitt's lymphoma who was receiving allopurinol. These markedly above-normal values for xanthine led to spuriously low values for serum uric acid as measured by the uricase method. Rapid tumor lysis in patients who are receiving allopurinol may lead to marked hyperxanthinemia, which in turn may obscure hyperuricemia in such patients when the uricase method is used for uric acid analysis. In such situations, uric acid concentrations should be measured by the phosphotungstate colorimetric assay.

Adult↗
PubMed2000

Lipid peroxidative damage in the erythrocytes and elevation of serum LDL-cholesterol, apolipoprotein-B, ferritin and uric acid with age and in coronary heart disease patients.

OBJECTIVES: To determine the normal serum levels of LDL-cholesterol, apolipoprotein-B, ferritin, uric acid, and the extent of erythrocytes lipid peroxidation in healthy control group subjects and to compare them with coronary heart disease patients. Secondly, to study the effects of age and sex on these parameters. METHODS: The blood samples from 150 healthy Libyan control group subjects (110 men and 40 women) were classified into 3 groups according to their age. Group I consisted of 76 subjects with an age range from 20 to 35 years. Group II consisted of 45 subjects with an age range from 36 to 50 years. Group III consisted of 29 subjects with an age range from 51 to 74 years. The blood samples from these groups were analyzed for LDL-cholesterol, apolipoprotein-B, ferritin and uric acid levels. Lipid peroxidation was compared in the erythrocytes of 56 selected healthy control group subjects (31 men and 11 women) of the aforementioned age groups. RESULTS: These parameters have shown age-dependent elevation in their levels. Meanwhile, LDL-cholesterol and Apolipoprotein-B levels in female subjects were higher than those of males. However, lipid peroxidation in the erythrocytes has revealed a statistically significant increase with increasing age. The comparison between 93 selected, sex and age matched, healthy control group subjects with 87 selected coronary heart disease patients (55 men and 45 women) with an age range from 30 to 74 years (49.6+13.25) has demonstrated significantly higher concentration of LDL-cholesterol, Apolipoprotein-B, ferritin and uric acid in coronary heart disease patients than those of healthy control group subjects. Meanwhile, lipid peroxidation was also significantly enhanced in coronary heart disease patients compared with healthy control group subjects. CONCLUSION: Our study has revealed that an increase in the lipid peroxidation in erythrocytes with age and during coronary heart disease, makes red cell membranes more vulnerable to free radical damage via formation of reactive oxygen species. It is thus likely that peroxidative damage may be contributing to an increase in serum LDL-cholesterol, Apolipoprotein-B, probably after its oxidative modification, increase in ferritin and hyperuricemia in coronary heart disease patients.

Adult↗
PubMed2001

Uric acid in cachectic and noncachectic patients with chronic heart failure: relationship to leg vascular resistance.

BACKGROUND: Chronic heart failure (CHF) is a hyperuricemic state, and capillary endothelium is the predominant site of xanthine oxidase in the vasculature. Upregulated xanthine oxidase activity (through production of toxic free radicals) may contribute to impaired regulation of vascular tone in CHF. We aimed to study the relationship between serum uric acid levels and leg vascular resistance in patients with CHF with and without cachexia and in healthy control subjects. METHODS: In 23 cachectic and 44 noncachectic patients with CHF (age, 62 +/- 1 years, mean +/- SEM) and 10 healthy control subjects (age, 68 +/- 1 years), we assessed leg resting and postischemic peak vascular resistance (calculated from mean blood pressure and leg blood flow by venous occlusion plethysmography). RESULTS: Cachectic patients, compared with noncachectic patients and control subjects, had the highest uric acid levels (612 +/- 36 vs 459 +/- 18 and 346 +/- 21 micromol/L, respectively, both P <.0001) and the lowest peak leg blood flow and vascular reactivity (reduction of leg vascular resistance from resting to postischemic conditions: 83% vs 88% and 90%, both P <.005). In all patients, postischemic vascular resistance correlated significantly and independently of age with uric acid (r = 0.61), creatinine (r = 0.47, both P <.0001), peak VO2 (r = 0.34), and New York Heart Association class (r = 0.33, both P <.01). This correlation was not present in healthy control subjects (r = -0.04, P =.9). In multivariate and stepwise regression analyses, serum uric acid emerged as the strongest predictor of peak leg vascular resistance (standardized coefficient = 0.61, P <.0001) independent of age, peak VO2, creatinine, New York Heart Association class, and diuretic dose. CONCLUSIONS: Hyperuricemia and postischemic leg vascular resistance are highest in cachectic patients with CHF, and both are directly related independent of diuretic dose and kidney function. The xanthine oxidase metabolic pathway may contribute to impaired vasodilator capacity in CHF.

Adult↗
PubMed2006

Role of uric acid in hypertension, renal disease, and metabolic syndrome.

Hyperuricemia has long been known to be associated with cardiovascular disease, and it is particularly common in people with hypertension, metabolic syndrome, or kidney disease. Most authorities have viewed elevated uric acid as a secondary phenomenon that is either innocuous or perhaps even beneficial, since uric acid can be an antioxidant. However, recent experiments have challenged this viewpoint. In this paper we argue that uric acid is a true risk factor for cardiovascular disease. Furthermore, we suggest that the recent increased intake in the American diet of fructose, which is a known cause of hyperuricemia, may be contributing to the current epidemic of obesity and diabetes.

Biomarkers↗
PubMed2006

Higher serum uric acid is associated with increased arterial stiffness in Japanese individuals.

Hyperuricemia is postulated to be a risk factor for atherosclerotic diseases, although whether it is independent of classical atherogenic risk factors is controversial. The automatic computer-assisted measurement of brachial-ankle pulse wave velocity (baPWV) is a valid and reproducible method by which to assess arterial stiffness, a potential surrogate marker of early atherosclerosis. By analyzing cross-sectional data from 982 individuals who underwent health screening, we have investigated whether serum uric acid is associated with high baPWV, which was determined as the highest quartile of baPWV values, in a sex-specific manner. Multivariate analysis showed that the odds ratios (95% CI) of the highest baPWV quartile across the sex-specific quartiles of serum uric acid were 1.0, 2.80 (0.93-8.40), 2.13 (0.74-6.19), and 2.76 (1.01-7.55) in women, and 1.0, 1.10 (0.55-2.20), 1.97 (1.04-3.75), and 2.24 (1.10-4.56) in men after adjusting for age, total and HDL-cholesterol, BMI, systolic blood pressure, triglycerides, fasting glucose and smoking status. The association between uric acid and high baPWV was observed in both subjects with metabolic syndrome and those without. These data suggest that in both genders, serum uric acid level is associated with increased baPWV, a marker of arterial stiffness, and is in part independent of other conventional risk factors for atherosclerosis and metabolic syndrome.

Aged↗
PubMed1995

Increased VLDL levels and diminished renal excretion of uric acid in hyperuricaemic-hypertriglyceridaemic patients.

The objective was to study the lipoprotein levels in primary hyperuricaemic patients and to analyse their renal management or urates in order to check for some potential influence of altered lipid levels on the renal excretion of urates by this type of patient. Overall 115 male individuals were studied in five groups, namely: 30 primary hyperuricaemic (group I); 27 primary hyperuricaemic-hypercholesterolaemic (group II); nine primary hyperuricaemic-hypertriglyceridaemic (group III); 33 primary hyperuricaemic-mixed hyperlipidaemic (group IV); and 16 normouricaemic-normolipidaemic subjects (group C). All patients were subjected to blood analyses for uric acid, total triglycerides, total protein, creatinine, high density lipoprotein (HDL) cholesterol, very low density lipoprotein (VLDL) cholesterol, low density lipoprotein (LDL) cholesterol, apoprotein (apo) AI, apoprotein B, apoprotein CII and apoproteins CIII1 and CIII2. For urine analysis creatinine, creatinine clearance, uric acid excretion, clearance and fractional excretion were measured in 24 h urine samples. Mixed and pure hyperuricaemic-hypertriglyceridaemic patients exhibited increased levels of VLDL components, decreased fractional excretion of uric acid and increased apo CIII/CII ratios. The increased levels of structural VLDL components were negatively (and statistically significantly) correlated with the fractional excretion of uric acid; this suggests a close biological relationship between the two parameters. Taking into account the role played by apo C in VLDL metabolism, the altered apo CIII/CII ratios found in hyperuricaemic-hypertriglyceridaemic patients (both pure and mixed) suggest that this apoprotein plays a central role in the physiopathology of the alterations observed.

Adult↗