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Query: UMLS:C0020500 (hyperoxaluria)
 912 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Considering the clinical heterogeneity of primary hyperoxaluria type I (PH1) and the fact that in many instances this diagnosis was made without enzymatic and immunohistochemical investigation, other disturbances of oxalate metabolism than those presently known can be expected in PH1. Using a gaschromatographic/mass spectrometric method that allows quantification of these acids, hyperoxaluria and hyperglycoluria was found repeatedly in two unrelated patients. The hyperoxaluria was unresponsive to pyridoxine. There was no nephrocalcinosis or urolithiasis. In the liver biopsy normal AGT activity and normal localization of this enzyme in the peroxisome was found. In one patient abnormal Km and maximal activity and mozaicism of AGT were excluded. Hyperoxaluria and hyperglycoluria were also found in other family members, suggesting autosomal dominant transmission. Although the underlying defect leading to hyperoxaluria and hyperglycoluria could not be identified in these patients, it is probable that they represent a separate type of primary hyperoxaluria.
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PMID:Hyperoxaluria with hyperglycoluria not due to alanine:glyoxylate aminotransferase defect: a novel type of primary hyperoxaluria. 891 45

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

Urolithiasis and/or nephrocalcinosis due to hereditary diseases are a rare event which must be kept in mind of physicians who take care of children (10 to 40% of all causes of lithiases) as well as of adults (less than 15% of all causes of lithiases) since a specific management is usually required. The most frequent inborn disorders are idiopathic hypercalciuria, distal tubular acidosis, cystinuria and hyperoxaluria. Stone formation is always secondary to an increased urine concentration of promotors, i.e. calcium, oxalate, phosphate, cystine, xanthine. One of the most informative diagnosis investigation is infrared spectrophotometry which can identify stone composition. When such a technique is not available, biochemical investigations should be adapted to both personal and family history. In addition to high fluid intake (2 to 3 L/m2/24 h) sometimes associated with alcalinisation, the management of hereditary stone disease requires specific procedure. In all cases, the long-term renal prognosis is related to both primary disease and therapeutic compliance.
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PMID:[Hereditary diseases causing kidney calculi]. 936 14

Calcium urolithiasis is often associated with increased intestinal absorption and urine excretion of calcium, and has been suggested to result from increased vitamin D production. The role of the enzyme 1 alpha-hydroxylase, the rate-limiting step in active vitamin D production, was evaluated in 36 families, including 28 sibships with at least a pair of affected sibs, using qualitative and quantitative trait linkage analyses. Sibs with a verified calcium urolithiasis passage (n = 117) had higher 24-h calciuria (P = 0.03), oxaluria (P = 0.02), fasting and postcalcium loading urine calcium/creatinine (Ca/cr) ratios (P = 0.008 and P = 0.002, respectively), and serum 1,25(OH)2 vitamin D levels (P = 0.02) compared with nonstone-forming sibs (n = 120). Markers from a 9-centiMorgan interval encompassing the VDD1 locus on chromosome 12q13-14 (putative 1 alpha-hydroxylase) were analyzed in 28 sibships (146 sib pairs) of single and recurrent stone formers and in 14 sibships (65 sib pairs) with recurrent-only (> or = 3 episodes) stone-forming sibs. Two-point and multipoint analyses did not reveal excess in alleles shared among affected sibs at the VDD1 locus. Linkage of stone formation to the VDD1 locus could be excluded, respectively, with a lambda d of 2.0 (single and recurrent stone formers) and 3.25 (recurrent stone formers). Quantitative trait analyses revealed no evidence for linkage to 24-h calciuria and oxaluria, serum 1,25(OH)2 vitamin D levels, and Ca/cr ratios. This study shows absence of linkage of the putative 1 alpha-hydroxylase locus to calcium stone formation or to quantitative traits associated with idiopathic hypercalciuria. In addition, there is coaggregation of calciuric and oxaluric phenotypes with stone formation.
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PMID:The 1 alpha-hydroxylase locus is not linked to calcium stone formation or calciuric phenotypes in French-Canadian families. 951 4

We investigated the effects of castration and finasteride administration on urinary oxalate (Ox) excretion in a rat ethylene glycol (EG) model of urolithiasis. Male adult SD rats were divided into six groups. Group 1 were normal, untreated rats. The other five groups, all treated with 0.75% EG for 4 weeks; were as follows: group 2, non-castrated (intact) rats; group 3, castrated rats; group 4, castrated rats with a 4-cm testosterone implant; group 5, intact rats treated with high-dose finasteride (7.5 mg%); and group 6, intact rats treated with low-dose finasteride (0.75 mg%). Urinary Ox excretion increased 12.8-fold after 4 weeks of EG treatment (group 2 vs group 1). Both castration (group 3) and finasteride administration (groups 5 and 6) significantly decreased urinary Ox excretion compared with intact rats (group 2). We conclude that dihydrotestosterone is partially responsible for the exaggerated hyperoxaluria observed in the rat EG model of urolithiasis.
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PMID:Effect of castration and finasteride on urinary oxalate excretion in male rats. 953

Idiopathic calcium nephrolithiasis (ICN) is a frequent disease in Western countries. The physicochemical theory of lithogenesis, which explains stone formation by the precipitation, growth, and crystalline aggregation of lithogenic salts in the urine, has contributed greatly to the understanding of the pathogenesis of calcium urolithiasis. However, several aspects are still unexplained; the co-existence of familial occurrence, primary tubular dysfunctions with ICN, and anomalies in the systemic handling of oxalate and calcium led to the development of a cellular hypothesis of ICN. A number of cellular defects in the handling of ions has been reported that involves both anion and cation transport. These anomalies are probably the expression of a still unknown cellular defect in idiopathic calcium stone formers. We suggested that an anomaly in the cell membrane composition might be responsible for the complex array of cell ion flux abnormalities observed in ICN. Recently, a disorder in the n-6 polyunsaturated fatty acid series has been described; it is characterized by a lower linoleic acid content and a higher arachidonic acid concentration in both plasma and erythrocyte membrane phospholipids of renal calcium stone patients. This anomaly could cause an increased activity of ion carriers; furthermore, it may lead to increased prostaglandin synthesis and to secondary phenomena at the kidney, skeletal, and intestinal level. As a consequence, critical conditions for lithogenesis in the kidney may ensue. The data suggest a common pathogenesis for hypercalciuria and hyperoxaluria. The systemic defect in the phospholipid arachidonic acid level may be both of dietary or genetic origin; experimental data suggest that the increase in delta-6 desaturase activity, the limiting enzyme in the metabolic pathway of polyunsaturated fatty acids, might be relevant to the pathogenesis of lipid abnormalities observed in nephrolithiasis and to the pathogenesis of ICN and its related problems (at the kidney, intestinal, and bone level).
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PMID:Pathogenesis of idiopathic calcium nephrolithiasis: update 1997. 959 25

Patients with cystic fibrosis (CF) have an increased risk of urolithiasis/nephrocalcinosis. To determine potential mechanisms responsible, we studied the urinary excretion of lithogenic and stone-inhibitory substances and calculated the urinary saturation for calcium-oxalate (CaOx), brushite (CaHPO4), and uric acid (UA). We examined 24-h urines in 63 patients with CF (34 female, 29 male) aged 5 months to 36 years. Renal ultrasonography was performed at the time of urine collection. Hyperoxaluria was found in 25 patients (range 0.51-1.71 mmol/1.73 m2 per 24 h). Urinary Ca was increased in 13 patients (4.1-8.22 mg/kg per 24 h). Hyperuricosuria was found in 16 patients (5.2-18.0 mmol/1.73 m2 per 24 h) and hypocitraturia in 14 patients (0.07-1.14 mmol/1.73 m2 per 24 h). CaOx saturation was elevated in 26 patients, related to hyperoxaluria in 19 patients. CaHPO4 saturation was increased in 19 patients and UA saturation in 11 patients. Urolithiasis in situ was diagnosed in 1 patient; 3 patients previously had renal stones; 4 patients had present nephrocalcinosis. Elevated excretion of lithogenic substances and urinary supersaturation might lead to the higher risk of urolithiasis/nephrocalcinosis in patients with CF.
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PMID:Urinary excretion substances in patients with cystic fibrosis: risk of urolithiasis? 965 56

Hyperoxaluria was reported to induce renal damage, probably due to toxic effects on renal tubules. Such tubular damage might be expressed by an increase in urinary excretion of marker enzymes such as N-acetyl-beta-D-glucosaminidase (NAG). We set out to examine a possible relationship between the excretion of NAG and that of urinary lithogenic and stone-inhibitory substances by analyzing 24-h urine specimens from 56 children with urolithiasis and 25 healthy children with normal renal function and without a history of urolithiasis. The NAG excretion was higher in patients with urolithiasis (3.5 +/- 0.51 U/g creatinine) as compared with healthy subjects (1.33 +/- 0.14 U/g creatinine, P < 0.05). A positive correlation between NAG and oxalate excretion was observed in female patients (r = 0.56: P < 0.01). In conclusion, the increase in urinary NAG in children with urolithiasis might express renal tubular damage. It seemed, however, not to be specifically related to the excretion of a single lithogenic substance.
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PMID:N-acetyl-beta-D-glucosaminidase excretion in healthy children and in pediatric patients with urolithiasis. 987 Feb 91

Calcium, in the form of regular food supplementation, can improve bone metabolism, but it can also increase the risk for renal calcium stones, and may aggravate pre-existing calcium urolithiasis. To study the first of these two aspects, ten healthy volunteers were given a conventional test meal (breakfast; calcium content 28 mg) with or without two dosages of calcium (as calcium-sodium citrate, CSC 1, 680 mg; CSC 2 1,360 mg), taken after an overnight 12 h fast. To study the latter aspect, patients with idiopathic recurrent calcium urolithiasis (ICU) received a balanced test meal of fixed composition, containing 1,000 mg calcium either as CSC (Meal + CSC3; n = 6) or as calcium gluconate (Mcal; n = 8). In normals, CSC induced a dose-dependent increasing intestinal absorption of calcium, and a decrease in oxalate absorption; in serum, CSC increased calcitonin and suppressed parathyroid hormone, but left unchanged the markers of bone turnover, serum osteocalcin and bone alkaline phosphatase. In urine, CSC decreased bone resorption markers (collagen crosslinks) and phosphaturia increased citrate, created signs of metabolic alkalosis, and inhibited several parameters of CaOx crystallization. In ICU, the CSC3 load failed to promote the crystallization of CaOx and calcium phosphate. It was concluded that CSC supplementation of a meal: (1) is well tolerated by healthy subjects and ICU patients, renders calcium highly available to bone, and prevents post-prandial oxaluria from rising; and, (2) is followed by the inhibition of crystallization of renal stone forming calcium-containing substances. Long-term studies aimed at evaluating the usefulness of CSC in preserving healthy bone, and in the metaphylaxis of renal stones would appear justified.
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PMID:Acute effects of calcium sodium citrate supplementation of a test meal on mineral homeostasis, oxalate, and calcium oxalate crystallization in the urine of healthy humans--preliminary results in patients with idiopathic calcium urolithiasis. 1042 48

Clinical effects of spa treatment on renal function in middle-aged and elderly male and female patients with chronic pyelonephritis and urolithiasis was studied. Combined sanatorium treatment included a course intake of low-mineral sulphate-hydrocarbonate calcium-magnesium mineral water Kazanskaia. Diuresis, especially daytime, was activated in all the patients. Maximum diuresis was observed in cool seasons in the elderly patients. To the end of the treatment proteinuria, oxaluria and uraturia diminished. A course of drinking mineral water Kazanskaia proved effective and is recommended for patients with chronic pyelonephritis and urolithiasis.
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PMID:[An efficacy study of the treatment of patients with chronic pyelonephritis and urolithiasis using sulfate-bicarbonate calcium-magnesium mineral water]. 1051 68


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