Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020500 (hyperoxaluria)
 912 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The normal value of oxaluria, as determined by gasliquid chromatography, is about 30 mg/24 h. In most cases of renal stone formation (60-70%) the stones are composed of calcium oxalate alone or associated with calcium phosphate. The more evolutive the disease, the higher the oxaluria. The part played by oxaluria in renal stone formation and the need to include its determination in regular examinations of stone formers must be stressed. Treatment of hyperoxaluria is both medicinal and dietetic : control of oxalic acid-rich food intake and reduction of the intestinal absorption of oxalate caused by calcium-deprived diets. The diet must be completed by therapeutic measures aimed at reducing the oxaluria and increasing the urinary factors preventing crystallization.
 ...
PMID:[Oxaluria in urinary lithiasis]. 622 3

Calcium and oxalate were studied in daily, fasting and postprandial urine specimens from healthy subjects and patients with idiopathic renal calcium stones in response to a test meal free of oxalate, and supplemented with calcium and 14carbon-oxalic acid. The data showed that the amount of oxalate in fasting urine of patients with stones did not differ from that in controls. Generally, patients with stones had considerable postprandial hyperoxaluria in terms of excretion and concentration, associated with a significantly higher degree of supersaturation with regard to calcium oxalate compared to controls. These findings were paralleled by decreased intestinal absorption of 14carbon-oxalate and by unchanged 24-hour urinary oxalate. Although the source of increased postprandial oxalate in patients with stones is not clear the possibility of enhanced de novo synthesis from oxalate precursors is discussed. In patients with different types of calciuria the 2 main risk factors (hyperoxaluria and hypercalciuria) for the process of stone formation are recognizable more readily in the postprandial urine specimens than in fasting or daily urine specimens.
 ...
PMID:Postprandial hyperoxaluria and intestinal oxalate absorption in idiopathic renal stone disease. 647 Dec 6

The authors report on metabolic studies on growing domestic pigs with resected ilea on a diet supplemented with oxalic acid and calcium. The content of calcium, magnesium and phosphate in the kidneys and ribs was determined and their excretion in urine was measured. The supplement of oxalic acid in the diet mainly affects the calcium content of the kidneys. It is also likely that oxalic acid inhibits the accumulation of calcium in the skeleton. Hyperoxaluria and hyperphosphaturia were established, whereas significantly less calcium and magnesium were excreted. The results of these animal experiments confirm previous clinical findings.
 ...
PMID:[Clinical and animal experiment studies on the pathogenetic significance of small intestine diseases and resections for urolithiasis]. 663 70

The circadian (circannual for oxalic acid) variations of 13 urinary variables (volume, creatinine, calcium, oxalic acid, glycolic acid, 17-ketosteroids, 17-hydroxycorticosteroids, phosphates, urea, uric acid, chloride, sodium, and potassium) have been documented in 7 calcium oxalate renal stone formers and 7 healthy men (control group). Urine was collected every 4 h over a period of 24 h. All subjects had the same synchronization: diurnal activity from 07(00) to 23(00) +/- 1 h and nocturnal rest; meals were given at fixed clock hours (08(00), 12(30) and 20(00) +/- 1 h). A statistically-significant rhythm (p less than 0.05) was validated for all variables except urea and calcium in healthy men. In renal stone formers, 6 variables (calcium, oxalic acid, and glycolic acid in particular) had no detectable circadian rhythm. However, a periodicity of c. 8 h (ultradian rhythm) was demonstrated for calcium and oxalic acid with peaks being located around 02(00), 10(00), and 18(00). No circannual variations in oxalic acid output could be observed. The present study shows an alteration of the periodicity of calcium and oxalic metabolisms, i.e. the loss of a circadian (24-h) rhythm and the occurrence of an ultradian rhythm of 8 h. The risk of calcium-oxalate crystallisation appears thus greater at 02(00), 10(00), and 18(00). Furthermore, any study dealing with oxalic acid excretion should state the season of urine collection when comparing renal stone formers and healthy subjects, as significant differences in oxaluria may appear during the summer months and not during the rest of the year.
 ...
PMID:Alterations in circadian rhythmicity in calcium oxalate renal stone formers. 686 98

A 32-year-old women was treated for overweight by gastrointestinal bypass surgery. Following surgery, repeated calcium oxalate nephrolithiasis was observed and secondary hyperoxaluria was diagnosed. Treatment with low oxalate and fat diet resulted in normal urinary oxalic acid excretion; no further stone formation was observed.
 ...
PMID:[Nephrolithiasis after intestinal bypass: successful treatment with a low-fat diet]. 731 47

Clinical and biochemical data were obtained from 50 patients in whom stones form and 20 controls to set up and test a screening procedure for detecting metabolic abnormalities related to the formation of urinary calculi and to provide a preliminary estimate of the frequency of these disorders in our area. A comparison between patients in whom stones form and controls in terms of the quantitative biochemical parameters evaluated (serum calcium, uric acid and inorganic phosphate, and urine calcium, uric acid, inorganic phosphate, oxalic acid, xanthine and alpha-amino-nitrogen) showed a significant difference only with respect to excretion of urinary oxalate by adults, which was higher in patients in whom stones form. Metabolic disorders were detected in 15 adult patients with stones. Of these patients 9 had isolated hyperoxaluria, 3 had incomplete renal tubular acidosis, 1 had idiopathic hypercalciuria, 1 had heterozygous cystinuria and 1 had idiopathic hypercalciuria associated with heterozygous cystinuria. These results suggest a high frequency of metabolic abnormalities in patients in whom stones form in our area, so that the wider use of the screening used here may benefit a large number of patients with preventive and therapeutic measures.
 ...
PMID:Metabolic factors in urolithiasis: a study in Brazil. 742 May 93

Ten car mechanics frequently exposed to glycol-based cooling liquids were followed during a workshift. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were measured. The car mechanics gave urine samples after the workshift and their excretion of ethylene glycol, propylene glycol, oxalic acid, calcium and ammonia was analysed and compared to that of unexposed office workers. Urinary succinate dehydrogenase activity and glycosaminoglycans were also measured in both groups. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were negligible. Urinary ethylene glycol excretion in exposed workers was significantly higher than that in unexposed workers, but propylene glycol excretion was at the same levels as in controls. In the exposed group, the excretion of the end metabolite of ethylene glycol, oxalic acid (47 +/- 11 mmol/mol creatinine, mean +/- SD, n = 10) differed slightly from that of controls (36 +/- 14 mmol/mol creatinine, mean +/- SD, n = 10). Urinary excretion of ammonia was higher among exposed workers than office workers. The excretion of calcium did not differ from that of controls. A marginally decreased urinary succinate dehydrogenase activity was found in the exposed men. The excretion of glycosaminoglycans was significantly lower in exposed workers. Therefore, it seems that ethylene glycol is absorbed by skin contact. The internal body burden is associated with oxaluria and increased ammoniagenesis typical of chronic acidosis.
 ...
PMID:Exposure to glycols and their renal effects in motor servicing workers. 757 1

Oxalate oxidase known to catalyse the aerobic oxidation of oxalic acid into CO2 and H2O2, has been found in bacteria, fungi, mosses and some higher plants. So far, a membrane bound oxalate oxidase from Pseudomonas sp. OX-53 and a soluble oxalate oxidase from seedling plants of barley and grain sorghum has been purified to homogeneity by conventional purification methods. The enzyme has been immobilized onto insoluble support such as nylon tubing, zirconia coated alkylamine glass, polyamide membrane, CO2 gas sensing electrode, H2O2 sensor probe and polyanionic electrolyte such as ethylaminemaleic anhydride (EMA). Compared to free enzyme the immobilized enzyme showed an increase in optimum pH, decrease in Vmax and time for maximum activity, higher resistance to inhibition by NaCl but no change in Km value. The immobilized enzyme has been used in both continuous flow system and discrete assays and in enzyme electrode for determination of oxalate in urine, blood and food stuff, which is essentially required for the diagnosis and treatment of hyperoxaluria and calcium oxalate urinary stones. The degradation of endogenous oxalate in rat by immobilized oxalate oxidase has opened a new vistas in enzyme therapy of hyperoxaluria.
 ...
PMID:Isolation, purification, immobilization of oxalate oxidase and its clinical applications. 818 50

The aim of this 17-day study was to examine the influence of four different diets on urine composition and the risk of calcium oxalate stone formation in 10 healthy male subjects. In the course of phase 0, the subjects were on their individual diet for 2 days. In the following phases I, II, and III the subjects received three different standard diets for a duration of 5 days each. Whereas DIET 1 (normal mixed diet) corresponded to the dietary habits of men aged 19 to 35 years, DIET 2 (balanced mixed diet) and DIET 3 (ovo-lacto-vegetarian diet) were calculated according to the dietary recommendations of the German Society of Nutrition (DGE) for the same age-group. The risk of calcium oxalate stone formation, calculated by the computer program EQUIL of FINLAYSON, was highest on the self-selected diet and on DIET 1, but declined significantly on the intake of DIET 2 by 50% on average compared to DIET 1 and by 61% compared to phase 0. On DIET 3 no further significant decline in the risk of calcium oxalate stone formation was observed. Therefore, it can be concluded that the change of usual dietary habits into a balanced mixed diet significantly reduces the risk of calcium oxalate stone formation. With a vegetarian diet a comparable decline in urine supersaturation of calcium oxalate can be achieved with respect to a mixed diet according to requirements. Since urinary oxalic acid excretion increased significantly, a vegetarian diet is not recommend for calcium oxalate stone patients with absorptive hyperoxaluria.
 ...
PMID:[The effect of different food forms on the urine composition and the risk of calcium oxalate stone formation]. 848 69

Urolithiasis is one of the most frequent causes of morbidity in developed countries and its incidence is close to 5%. In our experience, 67.4% of urinary stones contain calcium oxalate as the main component, and hyperoxaluria plays an important role in the pathophysiology of this type of stone. The mechanisms responsible for the increment in urinary excretion of oxalate could involve oxalic acid synthesis. This increase could be due either to an increment of its endogenous formation or to an exogenous load of its precursors. Furthermore, an increased intestinal oxalate absorption is a frequent cause of hyperoxaluria and urolithiasis. Ingestion of oxalate rich foods, imbalance in the supply of other nutrients that influence oxalic acid absorption and GI disorders with malabsorption and/or decreased degradation of intraluminal oxalate can increase intestinal oxalate transport and cause hyperoxaluria. In this article we review the physiological mechanisms that control the oxalate pool: endogenous synthesis, exogenous supply, intestinal absorption and renal excretion of oxalic acid. We analyze the causes and the pathophysiological mechanisms that increase urinary oxalate excretion. We describe a protocol for the biochemical study of patients with hyperoxaluria and the therapeutic measures to reduce urinary oxalate are reviewed. Finally, possible research that may provide further insight into oxalate metabolism in patients with hyperoxaluria are discussed.
 ...
PMID:[Hyperoxaluria and renal calculi]. 902 8


<< Previous 1 2 3 4 5 Next >>