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PubMed2000

In vitro and in vivo uric acid lowering by artificial cells containing microencapsulated genetically engineered E. coli DH5 cells.

Increase in systemic uric acid occurs in renal insufficiency, gout, chemotherapy, and other diseases. Dialysis can lower this metabolite but is expensive. The use of drugs can, sometime, result in side effects. Therefore, a suitable affordable method for this is required. In this article, for the first time, we report the use of artificial cells containing micro encapsulated genetically engineered E. Coli DH5 cells for lowering uric acid in vitro and in vivo. Results show that this novel approach has the ability to significantly lower uric acid from 84.80 +/- 3.40 mg/dl to 9.32 +/- 0.05 mg/dl in vitro and from the plasma of the experimental animals from the control levels of 71.00 +/- 27.49 mg/dl to 20.33 +/- 17.92 mg/dl in vivo. Continued daily oral administration maintained the plasma uric acid concentration of experimental uremic rats to the normal plasma uric acid level range during the entire test period.

Animals↗

PubMed1975

Hemodialysis for acute anuric uric acid nephropathy.

A patient with acute oliguric uric acid nephropathy was treated with hemodialysis. Recovery in this disorder is based on treatment of both the uremic state and the intrarenal crystal obstruction. Hemodialysis with high uric acid clearance is much more efficient than other forms of therapy in this disorder.

Abdominal Neoplasms↗

PubMed2004

[Measurement of uric acid of seminal plasma in fertile and infertile males].

OBJECTIVE: To measure uric acid of seminal plasma in fertile and infertile males. METHODS: One hundred and sixty-three infertile males were divided into an obstructive azoospermic group (15 cases), a non-obstructive azoospermic group (36 cases), an oligozoospermic group (43 cases), and an asthenozoospermic group (69 cases). Twenty fertile males were included in the control group. Uric acid concentrations of seminal plasma in the fertile and infertile men were assessed by spectrophotometer, and sperm parameters were analyzed by computer-assisted semen analysis (CASA) system. RESULTS: Uric acid concentration of seminal plasma in the control group was significantly higher than all the infertile groups (P < 0.01), and that of the obstructive azoospermic group significantly lower than the other infertile groups (P < 0.1), but no significant difference was observed among the other infertile groups (P > 0.05). CONCLUSION: Uric acid may play an important role in male reproduction because of its antioxidative property.

Adult↗

PubMed1991

Milk- and soy-protein ingestion: acute effect on serum uric acid concentration.

Acute effect of the ingestion of 80 g each of casein, lactalbumin, and soybean isolate on serum and urinary uric acid concentrations was investigated in 10 healthy subjects. Serum and urinary uric acid concentrations were measured before and after the ingestion of proteins. Serum uric acid decreased significantly 3 h after ingestion of lactalbumin and casein but increased after soybean consumption. Urate clearance was significantly increased after ingestion of each of the three proteins. Multivariate analysis of urate clearance during lactalbumin and casein loads showed that independent correlation was obtained for serum alanine and urea concentration. These results demonstrate that, in addition to their known uricosuric effect, milk proteins acutely decrease serum uric acid concentration. Analysis of the effects of lactalbumin and casein on urinary uric acid elimination suggests that the uricosuric effect of proteins is a multifactorial phenomenon.

Adult↗

PubMed1985

[Clinical value of the sequential study of the uric acid level in the CSF in patients with postoperative meningitis].

In this study we discuss the clinical value of the sequential measurement of the CSF uric acid and CSF cells in patients with postoperative acute meningitis. CSF was investigated for uric acid and cells in 10 cases with postoperative meningitis and 12 cases without it for the control group. The results were as follows; The CSF uric acid level was markedly increased in direct proportion to neutrophilia in the CSF in the acute stage of postoperative meningitis. Some cases with postoperative meningitis had biphasic increasing pattern of the CSF uric acid level. In 12 cases without postoperative meningitis the CSF uric acid level had been progressively reduced and then normalized until the fourth day after operation. The factors contributing to the increase of the uric acid in CSF under the condition of postoperative meningitis were thought to be 1) increased permeability of the blood-CSF barrier, 2) neutrophilia in the CSF and increase of the nucleic acid due to it, 3) increase of hypoxanthine, xanthine or xanthine oxidase activity in the central nervous system and 4) dysfunction of the CSF dynamics.

Adolescent↗

PubMed2003

Serum uric acid and plasma norepinephrine concentrations predict subsequent weight gain and blood pressure elevation.

It has been reported that hypertension and obesity often coexist with hyperuricemia. To clarify the relations between serum uric acid, plasma norepinephrine, and insulin or leptin levels in subjects with weight gain-induced blood pressure elevation, we conducted the present longitudinal study. In 433 young, nonobese, normotensive men, body mass index, blood pressure, and levels of serum uric acid, fasting plasma norepinephrine, insulin, and leptin were measured every year for 5 years. Subjects were stratified by significant weight gain and/or blood pressure elevation (>10% in body mass index or mean blood pressure) for 5 years. At entry, blood pressure, uric acid, and norepinephrine values in subjects with blood pressure elevation were greater than in those without it, although body mass index, insulin, and leptin were similar. At entry, body mass index, blood pressure, uric acid, and norepinephrine in subjects with weight gain were greater than in those without weight gain. The increases in body mass index, mean blood pressure, uric acid, norepinephrine, insulin, and leptin for 5 years were greater in subjects with blood pressure elevation and/or weight gain than in subjects without, and those increases were greatest in subjects with weight gain whose blood pressure was elevated. By multiple regression analysis, basal mean blood pressure, norepinephrine, and uric acid were significant determinant factors of changes in mean blood pressure over 5 years, and basal body mass index, norepinephrine, and uric acid were significant determinant factors of changes in body mass index. These results demonstrate that serum uric acid and plasma norepinephrine concentrations predict subsequent weight gain and blood pressure elevation.

Adult↗

PubMed1992

Quantitative separation of uric acid and allantoin from rat liver tissue.

A simple procedure is described for the assay of liver uric acid and allantoin and their specific radioactivity after administration of a radioactive precursor. Uric acid was quantified by the uricase reaction in liver trichloroacetic acid (TCA) extracts. The 'true' allantoin content of the liver could be estimated only after precipitation with Hg-acetate, a step by which the standard allantoin was also quantitatively recovered. Crude extracts lead to the evaluation of 'apparent' allantoin. For the determination of specific radioactivity, the Hg-acetate precipitate was further purified by ion-exchange chromatography. The purity of the two metabolites was confirmed by ultraviolet absorbance spectra, HPLC, constancy of specific radioactivity and the absence of amino acids. The incorporation of [14C]formate into uric acid and allantoin in the liver was studied by this procedure. The radioactivity in allantoin was several-fold higher than that in uric acid up to 60 min after administration of the precursor. This quite unexpected result is not easily explained on the basis of current knowledge.

Allantoin↗

PubMed2000

[Level of blood uric acid in patients with postinfarction heart failure].

AIM: To evaluate uric acid (UA) levels in patients with postinfarction chronic cardiac failure (CCF) and to investigate correlation between accumulation of uric acid, CCF severity and some other parameters. MATERIAL AND METHODS: UA levels were determined with enzyme immunoassay and acid-base status of capillary and venous blood was studied in 120 men 35-78 years of age (mean age 46.3 +/- 1.8 years) with CCF of NYHA functional class (FC) I-IV. CCF was caused by Q-wave myocardial infarction in all the patients. RESULTS: It was found that a close direct relationship exists between FC of CCF and UA content (r = 0.735, p < 0.001), FC of CCF and creatinine levels (r = 0.648, p < 0.001). Analysis of acid-base condition shows the existence of compensated gas acidosis in CCF patients. Acid-base changes were more prominent in FC III and IV. FC and gas acidosis directly correlated. CONCLUSION: In CCF there is a pathogenetic relation between high uric acid and hypoxia. However, further studies are necessary of the causes of UC rise in CCF and its influence on the severity of circulatory insufficiency.

Acid-Base Equilibrium↗

PubMed1982

The effect of prednisone and azathioprine (Imuran) on renal excretion of uric acid.

Our study was conducted in two groups of subjects with normal renal function and with normal metabolism of uric acid. Findings showed that the administration of prednisone (Group 1) results in increased renal excretion of uric acid. The observed significant increases in the renal clearance and fractional excretion of uric acid were not associated with any significant alterations in its plasma level. Further, our study did not confirm any effect of azathioprine (Imuran) (Group 2) on renal uric acid excretion, but its administration led to a significant reduction of its plasma level. Imuran appears to act on the metabolism of uric acid extrarenally.

Adult↗

PubMed1979

Changes of blood metabolites in horses after racing, with particular reference to uric acid.

Changes in concentration of a number of blood metabolites in 30 thoroughbred horses were recorded after an 1110 metre race. No significant changes occurred in blood urea or aspartate aminotransferase during the three hours after racing. Plasma sodium, potassium and calcium levels were increased immediately after racing but had returned to normal one hour after racing. Plasma phosphate showed a significant fall in concentration one hour after racing. Creatinine and lactic acid concentrations were elevated ten minutes after racing and although they subsequently decreased, the level of lactic acid was still significant one hour later. Uric acid levels were well above resting levels at ten minutes after racing but rose even more in the subsequent hour. Urinary uric acid levels were also elevated during this time. Three hours after racing some horses still had elevated plasma uric acid levels and all of them showed a significant rise in creatine phosphokinase. The possible physiological basis of these findings is discussed.

Animals↗

PubMed1984

Effects of sodium urate and uric acid crystals on the crystallization of calcium oxalate.

Crystallization of calcium oxalate in the presence of uric acid and sodium urate crystals was analyzed in a metastable crystallization system containing calcium chloride and sodium oxalate (A), in urine highly supersaturated with respect to calcium oxalate (B), and in urine with a high level of metastable supersaturation (C). In system A uric acid crystals in concentrations up to 11.4 mMol/l did not affect calcium oxalate crystallization, neither did sodium urate during the first 6 h in concentrations below 5 mMol/l. In system B neither uric acid nor sodium urate crystals affected calcium oxalate crystallization. However, an increased rate of crystallization was observed with both uric acid and sodium urate in system C, but the effect was less pronounced than with calcium oxalate seed. Urine pre-treated with sodium urate and subsequently analyzed in system A in a concentration of 2%, gave a slightly lower inhibition of calcium oxalate crystal growth. Concerning the crystal size distribution in the same system, larger crystals were observed in several urines pre-treated with uric acid and sodium urate.

Calcium Oxalate↗

PubMed1997

Relation between serum uric acid and lower limb blood flow in patients with chronic heart failure.

OBJECTIVE: To determine whether lower limb blood flow is related to serum uric acid concentrations in patients with chronic heart failure, taking into account the hyperuricaemic effects of diuretic treatment and insulin resistance. DESIGN: Lower limb blood flow was measured at rest and after maximum exercise followed by a five minute period of ischaemia (maximum blood flow) using strain gauge venous occlusion plethysmography. All patients underwent a metabolic assessment, which included an intravenous glucose tolerance test (IVGTT)-to obtain an index of insulin sensitivity- and measurement of serum uric acid. SETTING: University and hospital departments specialising in cardiology and metabolic medicine. SUBJECTS: 22 patients with chronic heart failure. RESULTS: Mean (SEM) resting and maximum blood flow values were 2.87 (0.23) and 24.00 (1.83) ml/100 ml/min, respectively. Patients in the upper tertile of serum uric acid had lower maximum blood flow than those in the lowest tertile (15.6 (2.2) v 31.0 (2.1) ml/100 ml/min, P = 0.003). Serum uric acid correlated with maximum blood flow (r = -0.86, P < 0.001), but not with resting blood flow. In stepwise regression analysis, uric acid emerged as the only predictor of maximum blood flow (standardised coefficient = -0.83 (P < 0.001), R2 = 0.68 (P < 0.001)), independently of diuretic dose, age, body mass index, plasma creatinine, fasting and IVGTT glucose and insulin, insulin sensitivity, maximum oxygen uptake and exercise time during the treadmill exercise test, and alcohol intake. CONCLUSIONS: There is a strong inverse relation between serum uric acid concentrations and maximum leg blood flow in patients with chronic heart failure. Further studies are needed to determine whether serum uric acid can be used as an index of vascular function in cardiovascular diseases.

Biomarkers↗

PubMed1975

Micropuncture study of uric acid transport in rat kidney.

Free-flow micropuncture studies were perfromed to evaluated uric acid transport in the rat kidney. In all studies (a-minus 14C) uric acid and (methoxy-3H) inulin wereadministered. A simple two-step, column-chromatographic technique was utilized to separate (2-minus 14C) uric acid from its labeled oxidation product in plasma, urine, and tubular fluid. Tubular fluid collections were obtained from the early-and late-proximal tubule under control conditions and during subsequent volume expansion induced with 0.9 per-cent sodium chloride. These studies indicate bidirectional, possible active, uric acidtransport in the proximal tubule undr control conditions, with net reabsorption evident early and net decretion apparent late in this nephron segment. In association with volumeexpansion net uric acid reabsorption and secretion both decreased. No significant nettransport was evident beyond the accessible portion of the late-proximal tubule in either experimental state.

Animals↗

PubMed2002

Uric acid is a main electron donor to peroxidases in human blood plasma.

BACKGROUND: Peroxidases are widely distributed and have been isolated from many higher-order plants, animal tissues, yeast and microorganisms. During measurements of peroxidase activities in samples of human plasma, we noticed the presence of a compound in the plasma which was interfering with the peroxidase assay. In this paper we describe the purification and characterization of this factor, which was identified as uric acid. MATERIAL/METHODS: The procedure used to purify uric acid from plasma involved ultra-filtration of the plasma, heat denaturation, DEAE-cellulose chromatography, and high performance liquid chromatography. The lyophilized powder was tested for homogeneity using an HPLC apparatus and capillary electrophoresis. Genuine uric acid samples were used for comparison. RESULTS: The compound obtained by the above-reported purification procedure was identified as uric acid by spectrophotometric analysis through comparison with genuine uric acid samples. Spectrophotometric measurements indicated that uric acid was degraded by HRP in the presence of H2O2. CONCLUSIONS: The experimental procedures described above allowed us to isolate and identify uric acid as the component in human plasma that acts as a true substrate for peroxidases.

Cellulose↗

PubMed1968

Determination of uric acid levels in uraemia by enzymatic and colorimetric techniques.

Serum uric acid levels were determined by specific and non-specific methods in uraemia in order to investigate the correlation between non-specific chromogen and serum urea level. The correlation was moderate and the magnitude of the non-specific chromogen was smaller than had been reported previously. The ratio [Formula: see text] urate was found to be 0.85 in both acute and chronic renal failure, a ratio very similar to that previously reported for normal and gouty subjects. In chronic renal failure the true uric acid level is correlated with urea level and there is a suggestion that serum uric acid levels in chronic renal failure are lower for a given urea value than in acute renal failure.

Acute Kidney Injury↗

PubMed1992

Raised urea clearance in cirrhotic patients with high uric acid clearance is related to low salt excretion.

In cirrhotic patients without renal failure, salt retention could result from a decreased effective intravascular volume or could be a primary event leading to increased intravascular volume. Clearance of urea and uric acid depend on an effective intravascular volume. In the syndrome of inappropriate secretion of antidiuretic hormone (SIADH)--a state of increased intravascular volume--uric acid clearance is increased and that of urea is increased only when salt excretion is low. The intravascular volume of 60 consecutive cirrhotic patients without renal failure was estimated indirectly by studying the relationship between fractional excretion of filtered (FE) sodium, urea, and uric acid. Forty five per cent had a high FE uric acid (> 12%), which could mean a high intravascular volume, and presented with an FE urea that was inversely correlated with FE sodium (r = 0, 62; p < 0.001) as in SIADH, while in the controls the FE urea was positively correlated with FE sodium (r = +0, 46; p < 0.01). In patients who had a normal FE uric acid and low FE sodium (< 0.2%), the FE urea was significantly lower (40 (13)%, n = 20) than in subjects with high FE uric acid and a low FE sodium (61 (9)%, n = 16, p < 0.001); this last group also presented with lower mean blood urea concentrations (3.1 (1.2) mmol/l and 4.0 (1.8) mmol/l; p < 0.05) and a lower supine renin activity (p < 0.01). As observed in the SIADH, cirrhotic patient with high FE uric acid have raised FE urea only when salt excretion is low. It is believed that the low salt excretion is not caused by a decrease in effective intravascular volume and that this is increased in cirrhotic patients with raised FE uric acid.

Adult↗

PubMed1980

[Serum uric acid - the longitudinal behavior and age (author's transl)].

The longitudinal behavior of serum uric acid was studied by regular determinations made on a total of 195 subjects (of whom 53 were males and 142, females) between 1968 and 1978. The concentration of uric acid showed a significant increase within ten years irrespective of age, sex, and body weight. Nutritional influences, problems of physical and mental activity, therapeutical measures and agents, as well as hormonal alteration are discussed as possible cause thereof. There were no correlation between change in relative weight and uric acid level. Serum cholesterol and uric acid trends showed negative correlations in young men and positive correlations in older men.

Adult↗

PubMed1984

High-performance liquid chromatography with polarographic and voltammetric anodic detection: simultaneous determination of allopurinol, oxipurinol and uric acid in body fluids.

Allopurinol, oxipurinol and uric acid have been determined in human serum and urine by liquid chromatography with electrochemical detection. In particular the use of a polarographic detector operating in the oxidative mode, whose principle of detection is based on the property of allopurinol, oxipurinol and uric acid to form insoluble anodic films on mercury, is described. The performance of such a detector is compared with that of a glassy carbon wall-jet detector. Different procedures for sample pretreatment have been evaluated.

Allopurinol↗