Dissolution of uric acid stones: alternative to surgery.
A method for the dissolution of uric acid urolithiasis by irrigation with sodium bicarbonate solution through a ureteral catheter is described.
Aged↗
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[Urinary excretion of calcium, magnesium, uric acid and oxalic acid in normal children].
A group of normal children with a free diet was studied. Their first morning urine (n = 176) and their 24-hour-urine (n = 64) was collected, valuing the calciuria, magnesiuria, uricosuria and oxaluria, establishing their relationship with a dietetic survey. Ca/Cr rate value was 0.13 +/- 0.7 mg/mg in the morning urine, and 0.12 +/- 0.06 mg/mg in the 24-hour-urine. Calciuria (mg/kg/day) was 2.46 +/- 1.45, higher to that noticed by other authors. Prevalence of hypercalciuria was 7.8%. We haven't noticed any correlation between the calciuria (mg/kg/day) and the consumption of proteins and carbohydrates. A positive correlation was found between Ca/Cr and Na/Cr rate, together with high natriuria (3.87 +/- 1.35 mEq/kg/day); these findings could justify the elevated calciuria in the children studied. Mean values of magnesium and uric acid were 0.04 +/- 0.02 and 0.30 +/- 0.08 mg/100 ml FG, respectively and the oxaluria was 34.51 +/- 16.35 mg/day/1.73 m2.
Adolescent↗
Effects of serum bilirubin on determination of uric acid by the uricase-peroxidase coupled reaction.
We examined the possible effect of different bilirubin species, including unconjugated (Bu), sugar-conjugated (Bc), and authentic delta bilirubin (Bd) isolated from serum, on the direct enzymatic measurement of uric acid by using the uricase (EC 1.7.3.3) and peroxidase (EC 1.11.1.7) coupled reaction. Bc, isolated from human bile, produced the most interference with uric acid determination. Although the presence of human serum albumin reduced interference by Bu and Bc, albumin-bound Bc complex still produced greater interference than Bu. Interference with the peroxidase reaction by Bc covalently bound to serum albumin (Bd) was less than that by Bu. We examined this phenomenon by using serum-isolated Bd obtained by ammonium sulfate precipitation and ultrafiltration and by using commercially available ditaurobilirubin (DTB) and chemically synthesized Bd (via Woodward's reagent, WBd) as surrogates for bile-isolated Bc and natural Bd, respectively. DTB produced the same amount of interference as natural Bc, but the interference produced by DTB in the presence of serum albumin was not the same as that produced by natural Bc with albumin. Our synthetic Bd appears to be a reliable surrogate for natural Bd in testing for bilirubin interference.
Bilirubin↗
Uric acid degrading enzymes, urate oxidase and allantoinase, are associated with different subcellular organelles in frog liver and kidney.
On the basis of differential and density gradient centrifugation studies, the site of the uric acid degrading enzymes, urate oxidase and allantoinase, in amphibia was previously assigned to the hepatic peroxisomes. Using specific antibodies against frog urate oxidase and allantoinase, we have undertaken an immunocytochemical study of the localization of these two proteins in frog liver and kidney, and demonstrate that whereas urate oxidase is present in peroxisomes, allantoinase is localized in mitochondria. Urate oxidase and allantoinase were detected by immunoblot analysis in both frog liver and kidney. The subcellular localization of these two enzymes was ascertained by Protein A-gold immunocytochemical staining of Lowicryl K4M-embedded tissue. Peroxisomes in frog liver parenchymal cells and kidney proximal tubular epithelium contained a semi-dense subcrystalloid core, which was found to be the exclusive site of urate oxidase localization. Allantoinase was detected within mitochondria, but not in peroxisomes of hepatocytes or proximal tubular epithelium. No allantoinase was detected in the mitochondria of nonhepatic parenchymal cells in liver and of the cells lining the distal convoluted tubules of the kidney. These results demonstrate that, unlike rat kidney peroxisomes which lack urate oxidase, peroxisomes of frog kidney contain this enzyme. Contrary to previous assumptions, these studies also clearly establish that urate oxidase and allantoinase, the first two enzymes involved in uric acid degradation, are localized in different subcellular organelles in frog liver and kidney.
Amidohydrolases↗
Uric acid levels in patients with multiple sclerosis: analysis in mono- and dizygotic twins.
Presence of nitrotyrosine in cells surrounding plaques indicates that peroxynitrite may be the cause of brain lesions in multiple sclerosis. Low levels of uric acid, a natural scavenger of peroxynitrite, were demonstrated in blood of patients with multiple sclerosis in comparison with control individuals. These observations were now extended to 132 sets of twins with one sibling affected by multiple sclerosis. In blood of both mono- and dizygotic twins the uric acid levels were lower in the twin with the disease than in the healthy twin.
Female↗
Uric acid is closely linked to vascular nitric oxide activity. Evidence for mechanism of association with cardiovascular disease.
OBJECTIVES: The study was undertaken to determine whether the mechanism of association of elevated serum uric acid level (SUA) with cardiovascular disease (CVD) is secondary to a common link with vascular nitric oxide (NO) activity. BACKGROUND: Epidemiologic studies demonstrate an association of elevated SUA with CVD. The mechanism of this association is unknown, but both may be linked via an impairment in vascular NO activity. To examine this, we determined the relationship of SUA to vascular NO activity and to CVD risk. We then determined the effect of enhancing vascular NO activity on SUA. METHODS: In part 1, individuals with various degrees of CVD (n = 458) were surveyed and underwent measurement of flow-mediated brachial artery vasodilation (FMV), a measure of vascular NO activity. In part 2, we performed an analysis of data pooled from six separate clinical trials of a medical food designed to enhance vascular NO activity in individuals with CVD (n = 217 subjects representing 253 treatment periods) to determine the effect on SUA. RESULTS: In part 1, of all risk factors tested, SUA was second only to age in correlation with FMV, accounting for 7% (p < 0.0001) of the variability in FMV. Both SUA and FMV were related to the degree of disease risk (p < 0.0001 and p = 0.00025 by analysis of variance, respectively). By multivariate analysis, SUA did not continue to contribute significantly to the determination of FMV. In part 2, enhancement of FMV (5.8 +/- 4 to 8.6 +/- 5, p < 0.0001) was associated with a decrease in SUA (5.5 +/- 1.5 to 5.0 +/- 1.5, p < 0.0001). There was no placebo effect on FMV or SUA. CONCLUSIONS: These results suggest that the association of elevated SUA with CVD may be a consequence of an impairment of vascular NO activity. This may be owing to an ability of NO to modulate uric acid production through its influence on xanthine oxidase activity.
Adult↗
Uric acid and glutathione levels during short-term whole body cold exposure.
Ten healthy subjects who swim regularly in ice-cold water during the winter (winter swimming), were evaluated before and after this short-term whole body exposure. A drastic decrease in plasma uric acid concentration was observed during and following the exposure to the cold stimulus. We hypothesize that the uric acid decrease can be caused by its consumption after formation of oxygen radicals. In addition, the erythrocytic level of oxidized glutathione and the ratio of oxidized glutathione/total glutathione also increased following cold exposure, which supports this hypothesis. Furthermore, the baseline concentration of reduced glutathione was increased and the concentration of oxidized glutathione was decreased in the erythrocytes of winter swimmers as compared to those of nonwinter swimmers. This can be viewed as an adaptation to repeated oxidative stress, and is postulated as mechanism for body hardening. Hardening is the exposure to a natural, e.g., thermal stimulus, resulting in an increased tolerance to stress, e.g., diseases. Exposure to repeated intensive short-term cold stimuli is often applied in hydrotherapy, which is used in physical medicine for hardening.
Acclimatization↗
Inhibition of free radical-induced DNA damage by uric acid.
Single-strand DNA breaks were produced in isolated rat liver nuclei incubated with 3 separate oxygen free radical generating systems: xanthine oxidase-acetaldehyde plus Fe(II); hematin-R(H)OOH; Fe(II)-H2O2. Uric acid inhibited the induction of damage in the first two systems only. At concentrations below those found in human plasma, it was particularly effective against strand breaks produced by hematin-cumene hydroperoxide. These results offer additional evidence that uric acid may function as a cellular protective agent against superoxide and hydroperoxyl free radical-induced cytotoxicity toxicity.
Acetaldehyde↗
Increased norepinephrine and uric acid levels in the spinal cord of arthritic rats.
The purpose of the present study was to investigate whether the level of norepinephrine and its rate of disappearance after decarboxylase inhibition were modified in the spinal cord of a chronic pain model: the arthritic rat. Chromatographic studies allowing the simultaneous determination of norepinephrine and uric acid by means of HPLC with electrochemical detection are described. The norepinephrine and uric acid levels in the spinal cord were higher in arthritic rats than in normal rats. In addition the rate of disappearance of the amine was increased in the dorsal part of the cord in arthritic rats. These results agree with previous reports suggesting an activating effect of nociceptive stimuli on descending noradrenergic systems. They also indicate that studies on purine metabolism in the CNS in inflammatory and/or pain processes will be of interest.
Animals↗
Age-dependent change of uric acid level in the dermis using cutaneous microdialysis.
BACKGROUND: We had proposed the usefulness of cutaneous microdialysis for the study of antioxidants in the skin. OBJECTIVE: We designed a study analyzing the level of uric acid in the skin, one of the major antioxidants, for an age-dependent change. METHODS: 16 healthy male volunteers were divided into two groups according to age. Eleven subjects were in their 3rd decade, under 30 years of age (young group) and the others were their 8th decade (old group), over 70 years of age. Dialysate samples were analyzed using high-performance liquid chromatography analysis. RESULTS: In the young group the mean level of uric acid was 31.9+/-16.1 microg/ml, while in old group it was 13.4+/-5.2 microg/ml. CONCLUSION: This result demonstrated an in vivo state of antioxidant level in the human skin and the age-dependent difference was concordant with other in vitro or ex vivo studies; therefore, cutaneous microdialysis could be used in analysis and monitoring studies including human antioxidants and anti-aging.
Adult↗
In vitro study of local solubility of uric acid stones with lithium carbonate.
The possibilities of local dissolution of uric acid calculi with Na hydrocarbonate, K carbonate and lithium carbonate were examined in vitro. The most promising results were obtained with lithium carbonate. The necessity for studies of the compound in laboratory animals before its use in humans is emphasized.
Bicarbonates↗
Percutaneous dissolution of uric acid calculi with THAM irrigation.
We describe two patients suffering from uric acid calculi; one had uremia due to obstruction in one kidney, and the other retained fragments after percutaneous nephrolithotomy. They were successfully treated by irrigation of a THAM (tris-hydroxy-methyl-aminomethane) solution through percutaneous nephrostomy.
Aged↗
Trichosporon adeninovorans sp. nov., a yeast species utilizing adenine, xanthine, uric acid, putrescine and primary n-alkylamines as the sole source of carbon, nitrogen and energy.
A new yeast species, Trichosporon adeninovorans, was isolated from soil by the enrichment culture method. Apart from adenine, the strain utilized uric acid, guanine, xanthine, hypoxanthine, 6,8-dihydroxypurine, putrescine, propylamine, butylamine, pentylamine, hexylamine and octylamine as sole source of carbon, nitrogen and energy. The structure of the cell wall of Tr. adeninovorans was ascomycetous. On the subcellular level growth on adenine or uric acid was accompanied with the development of microbodies in the cell. These cell organelles probably were the site of urate oxidase, an enzyme that, after growth on purine substrates, together with allantoinase was present at high activities. Low activities of adenine amidohydrolase and xanthine dehydrogenase were also demonstrated.
Adenine↗
Interrelations of PTH, cAMP, creatinine and uric acid in nephrectomized patients under DNA or PTH application.
Patients with reduced renal mass (i.e., nephrectomized) and slightly decreased renal clearance (70-80%) have been treated by 4 g DNA to study uricosuria. Prompt or prolonged renal excretion of uric acid and creatinine have been observed with indirect effects on parathyroid secretion. Urinary cAMP, however, failed to correlate to the change of parathyroid function. Reversely, PTH injection significantly increases uricosuria suggesting interrelated secretion of uric acid and cAMP of the proximal tubules. In some respects this model can be used to investigate increased DNA metabolism and parathyroid function.
Adult↗
Urine is a saturated equilibrium and not a metastable supersaturated solution: evidence from crystalluria and the general composition of calcium salt and uric acid calculi.
A computer algorithm is described which allows urine to be modelled as a saturated equilibrium solution with respect to any combination of the solids calcium oxalate, calcium hydrogen phosphate (brushite), amorphous calcium phosphate, uric acid, sodium hydrogen urate and ammonium hydrogen urate. It is demonstrated that this model of urine, unlike the widely accepted metastable supersaturated solution model, explains the long-known calcium salt crystalluria versus pH curves of both non-stone-forming and stone-forming urine. Further, the saturation model accounts for why most "infection" stones do not contain calcium oxalate and why most "urate" stones are composed solely of uric acid and not admixed with alkali metal hydrogen urate salts. The supersaturation model of urine cannot explain satisfactorily these well-known phenomena. For example, the supersaturation model predicts that virtually all "infection" stones should contain calcium oxalate along with calcium phosphate and, perhaps, struvite.
Calcium↗
[Clinical implication of the body mass and waist/thigh indices in hypertensive patients: correlations with blood uric acid levels].
Body mass index (BMI) and waist/thigh circumference (WTC) were estimated in 104 patients with mild and moderate arterial hypertension (AH) lasting for 8.4 +/- 3.2 years (63 men, 41 women, mean age 50.2(+)-9.6 years). Blood concentration of uric acid was tested with enzymes (Boehringer Mannheim kits). Only 5 of 104 examinees had BMI under 25. The majority of the patients (79%) had high WTC. Hyperuricemia was detected in 32 of 104 patients. Uric acid level in the blood correlates (r = 0.43) with WTC but not with BMI.
Anthropometry↗
Identification of uric acid and ascorbic acid by chromatography.
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Ascorbic Acid↗
[The importance of ionic strength and protein concentration in the dialysis performance of autoanalyzer systems for the enzymatic determination of uric acid (author's transl)].
An earlier method for the determination of uric acid (this journal 13, 89--96, (1975) was reevaluated. It was confirmed that it is necessary to add NaCl and a detergent to the wash fluid in order to obtain full sensitivity and linearity. Protein components in the samples or in secondary standard solutions also increase sensitivity and straighten the calibration curve of primary standard solutions. The effects are compared with results reported in the literature, and the possible mechanisms of these effects are discussed.
Autoanalysis↗