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Serum calcium, urea and uric acid levels were determined in 100 normal pregnant women and 50 patients with pre-eclampsia. Serum calcium levels were significantly lower and urea and uric acid levels higher in pre-eclampsia. Low levels of calcium were found as early as 28 weeks and can therefore be used for early diagnosis of pre-eclampsia.
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1. Uric acid estimations by the uricase-UV and the autoanalyzer colorimetric procedures were compared. 2. At all levels of serum uric acid concentration measured, results with the uricase-UV method were significantly lower than those with the phosphotungstate method. 3. The data indicate that the critical uric acid level (measured by the autoanalyzer) at which allopurinol, uricosuric, and other agents are instituted should be decreased approximately 10 per cent when determinations are done by the uricase method.
An enzyme-based flow-injection amperometric analysis system (FIA) for monitoring of uric acid and glucose is described. The oxidase and peroxidase enzymes are physically coimmobilised in a sandwich-type reactor and ferrocene serves as a mediator. The assays are based on the measurement of a reduction current resulting from the enzymatic reactions, at a glassy carbon electrode held at 0.00 mV (vs. Ag/AgCl). The high selectivity (ascorbic acid did not interfere) is coupled to high sensitivity (a detection limit of 30 and 60 nmol/l for uric acid and glucose, respectively; signal/noise = 3) and good stability (the enzymes remained active for more than 6 weeks at 30 degrees C). The usefulness of the assay in clinical chemistry is illustrated by the measurement of human serum uric acid and glucose concentration. The results obtained were in fairly good agreement with those obtained using conventional hospital laboratory methods.
OBJECTIVE: To analyze the utility of chemolysis and the double-J ureteral catheter in patients with uric acid calculi. METHODS: The study comprised 30 patients (28 men and 2 women) treated with chemolysis for uric acid calculi and who consulted for renal colic. The indication for placement of a double-J ureteral stent were pain, moderate-to-severe hydronephrosis, fever and urinary tract infection. The calculi were < or = 10 mm in size and were located in the renal pelvis (3), upper ureter (5), middle ureter (2) and lower ureter (23). RESULTS: The uric acid calculi were dissolved with intravenous and oral combination chemolysis. The double-J catheter was useful in the cases with urinary tract obstruction, fever or urinary tract infection. CONCLUSIONS: Medical treatment is useful in the management of uric acid calculi. The double-J catheter is beneficial in patients with urinary tract obstruction.
Commercially available uricase and peroxidase have been immobilized onto alkylamine glass and arylamine glass beads respectively. A discrete method has been developed to determine uric acid in serum using immobilized uricase and peroxidase. The method is based on generation of H2O2 from serum uric acid by immobilized uricase and its measurement by a colour reaction catalyzed by immobilized peroxidase. The minimum detection limit of the method was 8 microg/0.1 ml sample. The mean analytical recovery of added uric acid in serum was 87.5%. The within and between assay coefficient of variation (C.V.) were <6.58% and <10.77% respectively. The serum uric acid in apparently healthy adults and persons suffering from different disease was found to be 25-55 microg/ml, 32+/-2.25 (range, mean+/-S.D.) and 55-200 microg/ml; 52+/-6.4 (range, mean+/-S.D.) respectively by our method. A good correlation (r = 0.8170) was obtained between the serum urate values by this method and with those obtained by commercial Enzo-kit method.
We report on 8 azotemic patients with anuria or progressive oliguria owing to bilateral uric acid lithiasis. In 7 patients the precipitating cause of acute obstructive renal insufficiency was choking of at least 1 distal ureter with numerous small uric acid stones. In 6 of these ureters contrast retrograde ureterography showed relief of obstruction, which was believed to be owing to the stone dissolution properties of the contrast medium used. In situ alkalization via nephrostomy catheters achieved dissolution of obstructing stones in 3 tracts and systemic alkalization dissolved the stones in 3 others. An operation was necessary in 4 cases of large calculi, all of which showed some radiodensity, either because of super added calcification or phosphatic incrustation, rendering dissolution unfeasible. Methods of management of the obstructed tract caused by uric acid stone disease are evaluated and discussed.
In 16 CF-patients (age: 7-23 years; 7 females, 9 males) we analysed the serum concentration of uric acid after a standard meal and pancreatic enzyme supplementation by PANKREON FORTE or PANGROL 400 "neu" (both 2800-3000 U lipase/kg body mass/meal). Simultaneously we measured the uric acid excretion into the urine. We found an effective digestion and subsequent resorption of triglycerides and glucose but no significant changes of the uric acid serum levels during the 8-hours-test period. The uric acid excretion was lower than in the nocturnal period before the test. We conclude that a dangerous hyperuricemia and/or hyperuricosuria do not usually occur in pancreatic enzyme supplementation.
The divergence of the obtained results of uric acid determination in patients with proliferative diseases of the haemopoietic system who were given cefradine concomitantly induced the authors to carry out a more profound analysis of that problem. The serum uric acid concentration was determined by two methods. The method with phosphorotungstenic acid showed an effect of cefradine present in samples on overestimation of uricemia, while no such effect was noted when the enzymatic method was used.
Linear sweep in vivo voltammetry with carbon paste electrodes records a prominent peak at about 340 mV in the anterior caudate of rat brain. This peak is increased by microinfusion of uric acid or xanthine oxidase (which enhances conversion of hypoxanthine and xanthine to uric acid) and is decreased or eliminated by microinfusion of uricase. Allopurinol (a specific xanthine oxidase inhibitor) also decreases this peak when given either intracranially or intraperitoneally. Co-administration of uricase and allopurinol reliably eliminate the peak in question. These data suggest that uric acid, a purine metabolite that has been thought to be absent in brain, is formed locally in rat caudate and that uric acid is the sole component of the peak at 340 mV. In vivo voltammetry may be a useful new tool for studying brain purine metabolism.
Serum uric acid levels were determined in patients with psoriatic arthritis on and off medication, with rheumatoid arthritis on no medication likely to alter serum values, and in patients with uncomplicated psoriasis. Values in males were higher than those in females. A larger prevalence of values above the normal range were seen in males with psoriatic arthritis on uncontrolled medication (13-5%) and in males with rheumatoid arthritis (12%) than in the other groups. The means for both these groups were around the midpoints of the normal range. These findings suggest that hyperuricaemia is not a common characteristic of psoriatic arthritis.
A highly significant increase (P {lt} .005) in average uric acid level was found in the blood serum of 25 mongoloids in the age range of 2 to 12 years, with a mean age of 6 years, when levels were compared with those in nonmongoloid, mentally retarded children. These data confirm our previou results with 40 mongoloids whose mean age was 23.7 years, and indicate that elevated uric acid levels are present throughout most of the life of these subjects.
A high-performance liquid chromatographic method for determining catabolism products of nucleic acids and purines, such as oxypurines (i.e. uric acid, xanthine and hypoxanthine) and allantoin in the blood plasma of ruminants was developed. The plasma was deproteinized with 10% trichloroacetic acid. The method enabled determination of oxypurines without derivatization. Allantoin was determined after conversion with 2,4-dinitrophenylhydrazine to a hydrazone (GLX-DNPH). Separation of converted allantoin, uric acid, xanthine and hypoxanthine derivatives was carried out using two reversed-phase C18 columns. The combination of pre-column derivatization and gradient elution with monitoring of the effluent at 205, 254 and 360 nm provides a simple and selective analytical tool for studying oxypurines and allantoin in plasma. The total run time of the HPLC analysis was 60 min. The recovery of the purine derivatives (i.e. oxypurines and allantoin) added to the plasma was between 95 and 106%. Purine derivatives were stable when the processed samples were stored for 7 days at -10 degrees C. The low values of the intra-assay coefficient of variations (2.5-4.6%) and the low values of the detection limits (0.187-0.004 nmol) point to the satisfactory precision and sensitivity of the method.
Serum uric acid (SUA) was measured in 512 men and 254 women from two English regions and in 337 men from one Scottish region. Mean SUA levels were the same in the men (5-5 mg/100 ml) and similar in the women (3-9 and 4-1 mg/100 ml). The apparent rarity of gout in Scotsmen cannot be explained by regional differences in SUA levels or in the prevalence of hyperuricaemia (defined as SUA of 7-0 mg/100 ml or over) which was present in 6-6% of the English men and 8% of the Scots. SUA was positively correlated with weight and serum urea, and with age in women, but no variation was found with social class. Body weight was the most important predictor of SUA in both men and women and superior to measurements involving correction for height, such as ponderal index and calculated lean body mass.
A rapid and precise, reversed-phase high-performance liquid chromatography method for amniotic fluid uric acid is described. Detection of uric acid and other naturally occurring constitutents is based on UV absorption at a wavelength of 280 nm and direct electrochemical oxidation at a potential of +0.800 V. The total analysis time is short (20 min) and the assay requires only filtration of the samples. Uric acid levels were determined in 14 samples of amniotic fluid obtained during the 15th to 24th week of gestation. Results ranged from 0.897 to 4.39 mg per 100 ml of amniotic fluid.
Transient retinal and optic nerve ischemia lasting for 20 minutes was produced in Wistar rats by clipping bilateral common carotid arteries and coagulating both vertebral arteries by heat. The uric acid level in the retina and optic nerve were determined by high performance liquid chromatography with electrochemical detection just before induction of ischemia, 20 minutes after induction of ischemia, and after resolution of ischemia. Uric acid content in the optic nerve (28.0 +/- 4.5 ng/mg protein) was about 5 times higher than that in the retina (5.7 +/- 0.8 ng/mg protein) in the control experiment. Ischemia lasting for 20 minutes caused a 2.7-fold increase of uric acid in the optic nerve and a 1.8-fold increase in the retina. Following reperfusion of the blood flow by unclipping of the common carotid arteries, the uric acid level decreased to the control level in both the retina and optic nerve 30 minutes after unclipping, which was followed by 3.1- and 1.6-fold increases in uric acid in the retina and the optic nerve, respectively, at 60 minutes after unclipping. Although ischemia alone causes tissue damage, there is some clinical evidence that greater injury can occur after oxygen is reintroduced to ischemic tissue. Our results indicate that the retina is more likely to be damaged by reperfusion than the optic nerve.
A 26-year-old woman was found to have an abnormally sensitive excretory response to a rise in plasma urate with a markedly increased ratio of uric acid to creatinine clearance (exceeding 35%). Uric acid was studied before and after administration of pyrazinamide and benzbromarone. In the presence of pyrazinamide urinary uric acid decreased markedly just as in normal subjects. The uricosuric response to benzbromarone was reduced. No other renal tubular or metabolic abnormalities were found. It appears that the abnormality is related to an isolated defect in postsecretory reabsorption of urate.
It's reported that oral administration of fructose in normal and gouty patients causes a rise in serum uric acid (see "References": Stirpe et al.). The changes in serum uric acid after administration of fructose to gouty patients and to children of gouty patients were significantly different from the changes observed in normal subjects, both for the extent and for the duration of hyperuricaemia. In this study the authors verify if the fructose-induced hyperuricaemia can help to identify gouty patients from people with different metabolic alteration of serum uric acid levels (i.e. chronic leukaemias and some neoplastic diseases).