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Query: UMLS:C0451641 (urolithiasis)
 3,973 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sodium oxalate (402 mg) was administered in a single dose to 10 healthy volunteers receiving a controlled diet. Half the group received 3 times 10 g Colestid and the other half 4 times 2 g Andursil. On the 5th day the oxalate load was repeated. Urine was collected within 32 hours following oxalate application in 8 fractions. In each fraction the levels of oxalate, calcium, phosphate and uric acid were determined. The amount of oxalate, phosphate and uric acid measured in the group receiving Colestid was lower in all fractions. Peak excretions of oxalate found in unmedicated volunteers were suppressed following oxalate load. In the group receiving Andursil, only the excretion of phosphate was decreased. The results presented suggest that Colestid may be promising in the prevention of calcium-oxalate-urolithiasis.
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PMID:[Test of efficacy of an oxalate-binding anion exchanger Colestid in healthy subjects for use in idiopathic calcium-oxalate urolithiasis]. 728 80

After a short historical survey the interest of our Socialist state in an optimum nutrition and nutritional education of the citizens is described. The importance of prophylaxis, therapy and metaphylaxis of urolithiasis is proved by the increasing morbidity rate of this disease (1-3%). Out of the series of vitamins above all the vitamin B6 is of importance in the oxalate lithiasis so that a diet rich in vitamin B6 is indicated. Of the quantity elements contained in nutrition calcium, phosphorus and magnesium are significant, wherefore the enteral supply of these elements is to be taken into consideration in the various kinds of urinary calculi. Furthermore, in carriers of calcium oxalate calculi nutrients rich in oxalic acid and in carriers of urinary calculi and in hyperuricaemia, respectively, nutrients rich in purine should be restricted. Adequate tables concerning the vitamin B6, Ca, P, Mg, oxalic acid and purine content of the nutrients are given. The increasing importance of the adiposity of carriers of uroliths is represented with the help of indices of our own urolith dispensary. Finally short references to diet for the 4 most important kinds of uroliths are proposed.
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PMID:[Value of dietetics and general nutritional guidelines in the metaphylaxis of urinary calculi]. 741 94

Urine activity product ratios of uric acid, sodium urate, and ammonium urate and urinary excretion of metabolites were determined in 24-hour samples produced by 6 healthy Beagles during periods of consumption of a low-protein, casein-based diet (diet A) and a high-protein, meat-based diet (diet B). Comparison of effects of diet A with those of diet B revealed: significantly lower activity product ratios of uric acid (P = 0.025), sodium urate (P = 0.045), and ammonium urate (P = 0.0045); significantly lower 24-hour urinary excretion of uric acid (P = 0.002), ammonia (P = 0.0002), sodium (P = 0.01), calcium (P = 0.005), phosphorus (P = 0.0003), magnesium (P = 0.01), and oxalic acid (P = 0.004); significantly (P = 0.0001) higher 24-hour urine pH; and significantly (P = 0.01) lower endogenous creatinine clearance. These results suggest that consumption of diet A minimizes changes in urine that predispose dogs to uric acid, sodium urate, and ammonium urate urolithiasis.
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PMID:Diet effect on activity product ratios of uric acid, sodium urate, and ammonium urate in urine formed by healthy beagles. 777

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.
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PMID:[Hyperoxaluria and renal calculi]. 902 8

In up to one-third of patients with calcium oxalate stones, a hyperoxaluria can be detected. Hyperoxaluria can result from increased endogenous production, from excessive oxalate content of the food, or from intestinal hyperabsorption. For a causal therapy, it is important to discriminate between metabolic and hyperabsorptive hyperoxaluria. Our new 13C-oxalate test allows this differentiation. Under standardized conditions, 50 mg of disodium salt of [13C2]oxalic acid was applied. From the amount of labeled oxalate excreted in urine as measured by a gas chromatographic-mass spectrometric assay, the intestinal absorption was calculated. Seventy patients with recurrent calcium oxalate urolithiasis who had no signs of inflammatory bowel disease were tested. Their mean intestinal oxalate absorption was 9.2+/-5.1%. This was significantly higher than the mean absorption of 50 healthy volunteers (6.7+/-3.9%). There was no difference in oxalate absorption between male (n = 25) and female volunteers. Oxalate absorption correlated with the oxalate excretion in the 24-h urine (volunteers: r = 0.46, P < 0.01; patients: r = 0.62, P < 0.001). Oxalate hyperabsorption was defined as an absorption exceeding 10%. According to this definition, 34% of the patients had oxalate hyperabsorption; 20% of the volunteers showed a hyperabsorption, too. The 13C-oxalate absorption test allows reliable determination of intestinal oxalate absorption. Because of the use of a stable isotope, this test may be repeated as often as required. It will allow the control of therapeutic regimens and also help to unravel genetic influences in stone formation.
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PMID:Intestinal hyperabsorption of oxalate in calcium oxalate stone formers: application of a new test with [13C2]oxalate. 1054 Dec 57

The evaluation of urinary oxalate excretion is one of the most important diagnostic methods in patients with urolithiasis and/or nephrocalcinosis. Since reliable 24-h urine collections are difficult to obtain in children, excretion ratios of oxalate over creatinine are increasingly being used from single urine specimens. The aim of the study was to determine the normal values of oxalate/creatinine ratios in the second morning urine sample in healthy school children. The study involved 109 children between 6 and 16 years of age. The results showed that the values of Ox/Cr ratios are decreased in older children and there was significant difference between children under and above 12 years of age (values of the 95th percentile--0.076 and 0.051 mmol/mmol respectively). The significant correlation between 24-hours urinary oxalic acid excretions and Ox/Cr ratios (r-0.756) was found. We conclude, that Ox/Cr ratio is valuable parameter for screening purposes in children.
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PMID:[Evaluation of oxalate/creatinine ratio in the second morning urine sample of health school children]. 1143 74

Urolithiasis is a common clinical disorder. Its frequency has risen with the development of humanity and varies wirl the country, geographic area, etc. It poses health problems in most countries. The urolithiasis has some potential risk factors such as intrinsic and extrinsic epidemiological, metabolic, physic-chemistry of the urine, mechanics and urinary infection. Our objective in this epidemiological study in a general population was to know the frequency, the potential risk factors, the morbidity, and social and economical impact of the urolithiasis in our subtropical Caribbean country. The prevalence was 4.64% and the annual incidence was 0.1%. Both are with in the estimated range of urolithiasis frequency in the world. It mainly started between 20 and 29 years in both genders. The white (5.2%) and the male (6.36%) patients were the most affected. 40% of all patients had a family history of urolithiasis. It was highly associated with diabetes mellitus, ischaemic cardiopathy, urinary tract infection and arterial hypertension. Stone formation was related to the warmer season. High calcium, protein-purine, carbohydrates and oxalic acid intake together with low fluid intake were closely associated with this disorder. 85% of patients had suffered renal colic and 75% of them more than once. Stone recurrence affected 33.8% of patients and 54.5% of them had more than one recurrence. Procedures for stone removal were needed in 33.8% of subjects. 40% of all patients were admitted to hospital due to urolithiasis morbidity. Non-specific medical treatment had been taken by 49.2% of the patients and specific treatment by none. Urolithiasis in this population was the some as has been reported in others studies. It has shown high frequency, increasing incidence, the same risks factors, high morbidity, and high social and economical impact. The low cost treatment is only taken by half of the patients.
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PMID:[Clinico-epidemiologic study of urolithiasis in a Caribbean urban area]. 1212 23

It has been suggested that renal tubular cell damage induced by oxalic acid, one of the components of urinary calculi, may be involved in a variety of ways in the development of urolithiasis. During our study on a calculus related protein, renal prothrombin fragment-1 (RPTF-1), we noted that this is an inflammation related substance that mediates an acute inflammatory reaction, one of the original roles of prothrombin. RPTF-1 is a part of prothrombin that is a coagulation factor known to be expressed in the renal tubule. We examined whether oxalic acid may cause cytotoxic effects on tubular epithelial cells and whether such chemical stimulation may promote the translation of RPTF-1 mRNA into RPTF-1 proteins. We used Madin-Darby canine kidney (MDCK) cells derived from the distal tubule of a dog kidney. In this study, the effects of oxalic acid in culture solution at different concentrations on cytotoxicity were assessed using a MTT assay. The location of active oxygen species was identified using dichlorofluorescein diacetate. After the prothrombin sequence of RPTF-1 was confirmed in MDCK cells, RPTF-1 mRNA expression was determined by RT-PCR. The gene sequence of the same promoter area was ligated, and a luciferase sequence was inserted downstream of the vector. The target sequence was transfected into MDCK cells and the relation between oxalic acid and prothrombin promoter was examined. In addition, the variable expression of RPTF-1 mRNA was quantitatively compared depending on oxalic acid concentrations using real-time PCR. When cytotoxicity was investigated, cells were not damaged but, by contrast, were stimulated and activated under oxalic acid below a certain concentration. The relation between cytotoxicity on the cultured MDCK cell membrane and active oxygen species was confirmed. Luminescence in MDCK cells containing the luciferase gene was detected by the addition of oxalic acid, which activated the prothrombin promoter. A part of the prothrombin gene sequence in the MDCK cells was detected and an increase in the expression of RPTF-1 mRNA in MDCK cells by the addition of oxalic acid was confirmed using real-time PCR. Increased expression of prothrombin by adding oxalic acid has already been demonstrated in previous studies. In this study, however, RPTF-1 mRNA was promoted by oxalic acid and a direct association between oxalic acid and RPTF-1 is indicated. This finding shows that increased oxalic acid in urine induces the expression of RPTF-1 in tubular epithelial cells and thereby causes the generation of active oxygen species.
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PMID:Effects of oxalate exposure on Madin-Darby canine kidney cells in culture: renal prothrombin fragment-1 mRNA expression. 1632 15

Of decisive importance for the many research groups all over Europe were the scientific symposia dealing with the theoretical foundations and clinical aspects of urinary stone disease. There were several sources from which today's European Urinary Stone meetings and the "Eurolithiasis Society" itself arose. It was a long way from Leeds in 1968 to Jena 1970, Bonn-Vienna in 1972 and to 11 European meetings from 1989 to 2005. Which developments in urinary stone disease research have been presented at our congresses during the past 40 years? The 1970s and 1980s are the years marked by efforts to measure the important lithogenic substances such as calcium, ionized calcium, uric acid, phosphate, oxalate with reliable methods. Hypercalciuria and specifically mild hyperoxaluria were the topics of numerous investigations in the 1970s, 1980s and 1990s. The calcium-loading test described by Pak has been discussed frequently since its application. It became apparent that oxalic acid is more important in urinary stone formation than hypercalciuria. Of importance were investigations done by Robertson and his colleagues on the influence of diet (in particular, an animal protein-rich diet) on urinary stone formation. Another emphasis of research was investigation of the crystallization process: supersaturation, crystal growth and aggregation are important steps in urinary stone formation. Of great importance in the formation of urinary stones are inhibitors (inhibitory activity): citrate, magnesium, pyrophosphate, macromolecules: GAGs, THP etc. and it became possible in the early 1970s to determine substances such as Tamm-Horsfall protein (THP) and GAGs. Much attention in the 1970s and 1980s was focused on urinary stone analysis (X-ray diffraction, infrared spectroscopy, polarization microscopy) and standardization of these methods. In the mid-1980s, a whole series of epidemiological studies were carried out, with data for the Federal Republic of Germany, East Germany, Czechoslovakia and Austria. The search for "stone-removing" medications, their description and clinical use was the subject of much clinical research and in vitro examinations. A definite advance occurred in the 1980s with the development of new instrumental technologies for the management of urinary stones such as shockwave ("Stosswelle") lithotripsy, percutaneous nephrolithotomy and ureterorenoscopy (" breakthrough innovations"). Since the 8th European Urolithiasis Symposium there have regularly been presentations pertaining to the topic of the molecular basis of inherited lithiasis. The last 10-15 years have shown an increasing turning toward the importance of cellular alterations and supersaturation and their relation to stone formation. In conclusion, I would like to note that it is of decisive importance for the research groups all over Europe to organize scientific symposia dealing with the theoretical foundations and clinical aspects of urinary stone disease under the protection of the European Urolithiasis Society.
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PMID:Thirty-eight years of stone meetings in Europe. 1650 36

Oxalic acid is found in dietary sources (such as coffee, tea, and chocolate) or is produced by the intestinal microflora from metabolic precursors, like ascorbic acid. In the human intestine, oxalate may combine with calcium, sodium, magnesium, or potassium to form less soluble salts, which can cause pathological disorders such as hyperoxaluria, urolithiasis, and renal failure in humans. In this study, an operon containing genes homologous to a formyl coenzyme A transferase gene (frc) and an oxalyl coenzyme A decarboxylase gene (oxc) was identified in the genome of the probiotic bacterium Lactobacillus acidophilus. Physiological analysis of a mutant harboring a deleted version of the frc gene confirmed that frc expression specifically improves survival in the presence of oxalic acid at pH 3.5 compared with the survival of the wild-type strain. Moreover, the frc mutant was unable to degrade oxalate. These genes, which have not previously been described in lactobacilli, appear to be responsible for oxalate degradation in this organism. Transcriptional analysis using cDNA microarrays and reverse transcription-quantitative PCR revealed that mildly acidic conditions were a prerequisite for frc and oxc transcription. As a consequence, oxalate-dependent induction of these genes occurred only in cells first adapted to subinhibitory concentrations of oxalate and then exposed to pH 5.5. Where genome information was available, other lactic acid bacteria were screened for frc and oxc genes. With the exception of Lactobacillus gasseri and Bifidobacterium lactis, none of the other strains harbored genes for oxalate utilization.
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PMID:Transcriptional and functional analysis of oxalyl-coenzyme A (CoA) decarboxylase and formyl-CoA transferase genes from Lactobacillus acidophilus. 1651 36


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