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

The effect of hydroxypyruvate on synthesis of oxalate and glycolate from glyoxylate was studied in in vitro preparations from normal human erythrocytes and leukocytes, rat liver, and with purified lactate dehydrogenase from beef heart. In the presence of reduced nicotinamide adenine dinucleotide, hydroxypyruvate stimulated the oxidation of glyoxylate to oxalate and decreased the reduction of glyoxylate to glycolate. These findings may explain the hyperoxaluria seen in L-glyceric aciduria (type II primary hyperoxaluria).
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PMID:Hyperoxaluria in L-glyceric aciduria: possible pathogenic mechanism. 432 74

Because of mounting evidence of precipitation of calcium oxalate in the soft tissues of patients with end-stage renal disease (ESRD) on maintenance hemodialysis, the plasma oxalate concentrations and calculated dialysis removal of oxalate were studied in seven patients without evidence of either primary or absorption hyperoxaluria prior to ESRD. A reversed-phase high-pressure liquid chromatographic method was developed to quantitate serum oxalate. Mean value +/- SE in four healthy controls was 28 +/- 5 mumol/L, and in the seven patients it was 187 +/- 15 mumol/L predialysis and 89 +/- 11 mumol/L postdialysis. Oxalate deposition in the soft tissues of ESRD patients is the consequence of sustained hyperoxalemia. Oxalate removal by dialysis was calculated from the four-hour oxalate clearance. Since the ionic radii of phosphate and oxalate are similar, total oxalate clearance was calculated midpoint of dialysis. Mean oxalate removal/dialysis was 3.01 +/- 0.283 mmol. On a daily basis this value was 1.645 +/- 0.155 mmol, which is about threefold the normal oxalate excretion rate. It is not significantly different from the excretion rate in absorption oxalurias but is less than that in primary hyperoxaluria. Therefore, it is concluded that hyperoxalemia in ESRD results from loss of renal excretion, failure of hemodialysis to remove enough oxalate to maintain a normal serum concentration, and increased intestinal absorption of oxalate and/or increased endogenous production.
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PMID:Oxalate removal by hemodialysis in end-stage renal disease. 647 42

Changes in oxalate excretion (together with changes in urinary volume) constitute the most important factors in altering the probability of renal stone formation. However, investigations on oxalate metabolism have been sparse, perhaps because of the lack of an accurate method for measuring oxalate in biologic fluids. Available data clearly implicate increased urinary oxalate excretion as the etiological factor in stone formation in two groups of patients--those with primary hyperoxaluria and those with gastrointestinal malabsorption. Evidence for the existence of hyperoxaluria in the patient with the "garden" variety of calcium oxalate stones is less persuasive.
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PMID:Oxalate metabolism and renal calculi. 703 92

In three patients with end-stage renal failure due to primary hyperoxaluria type 1, successful combined liver-kidney transplantation enabled us to assess the insoluble oxalate pool, which was compared with the histopathological changes observed in iliac crest biopsy specimens. Good correlation was observed between the histopathological grade of bone oxalosis and the estimated oxalate content of the body. In the end-stage of oxalate bone disease, hyperparathyroidism does not play a significant role in bone resorption, which appears to be the consequence of the granulomatous reaction induced by oxalate deposition. Combined liver-kidney transplantation should be performed long before this stage. Early hepatorenal grafting in uremia secondary to primary hyperoxaluria type 1 would avoid the deleterious clinical consequences of systemic oxalosis and shorten the duration of postransplant hyperoxaluria, which may compromise the course of kidney graft.
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PMID:Combined liver-kidney transplantation in primary hyperoxaluria type 1. Bone histopathology and oxalate body content. 760 40

Hyperoxaluria is characterized by nephrocalcinosis and nephrolithiasis on radiological examination and may also result in diffuse deposition of calcium oxalate crystals in multiple extrarenal organs (oxalosis). In two cases, the renal findings of primary hyperoxaluria were diagnosed by ultrasound and computed tomography scans. In addition to renal involvement, both patients had liver involvement, and one patient had cardiac involvement.
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PMID:Systemic oxalosis: pathognomonic renal and specific extrarenal findings on US and CT. 776 Nov 52

Evidence for the suitability of spot urines for selective screening in children was obtained by comparing the 24-hour urinary oxalate excretion with the ratio of urinary oxalate to creatinine [mmol/mol] in spontaneously voided urine samples. Spot urines of 169 healthy children aged 1 day to 13 years were analysed in order to establish reference values for the urinary oxalate/creatinine ratio in relation to age and body surface area. Oxalate was measured by automated ion chromatography. Results showed an inverse relationship between the oxalate/creatinine ratio and age. The highest ratios, 131 +/- 57 mmol/mol (mean +/- 2 SD), were found in infants. At age two years, the ratio was 84 +/- 55, at age five years 56 +/- 35, and for children older than ten years 42 +/- 31. This finding can be explained by the gain of muscle mass and hence increased creatinine production with increasing age. Data for the urinary oxalate/creatinine ratio are presented according to body surface area for the assessment of children with abnormal growth. In 19 urine samples from nine patients with primary hyperoxaluria, the oxalate/creatinine ratio greatly exceeded (286-2022 mmol/mol) the above reference ranges. We therefore propose the determination of the oxalate/creatinine ratio in spot urines for the selective screening for hyperoxaluria in children with nephrocalcinosis or urolithiasis.
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PMID:Determination of oxalate excretion in spot urines of healthy children by ion chromatography. 816 90

The study describes the indications and results of combined liver/kidney transplantation in eight patients suffering from end-stage hepato-renal diseases. The causes of primary renal failure were hyperoxaluria type I (2/8), diabetic nephropathy (2/8), glomerulonephritis (2/8), congenital pyelonephritis (1/8), and polycystic kidneys (1/8). Only five of these patients were on chronic dialysis prior to transplantation. The indication for kidney transplantation in the other three patients was low GFR (< 20 mL/min) and the anticipation of further deterioration of the renal function after liver transplantation as a result of cyclosporine toxicity. The end-stage liver diseases were chronic active hepatitis (4/8) and alcoholic cirrhosis (2/8). There was no evidence for liver failure in two patients undergoing combined transplants for primary hyperoxaluria. The 1-year patient survival rate is 75 per cent, and at that time, kidney and liver function were found to be within normal range. In conclusion, excellent long-term patient survival, as well as kidney and liver graft function, can be achieved in patients suffering from complex end-stage disease of both organs who undergo combined liver and kidney transplantation.
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PMID:The role of combined liver/kidney transplantation in end-stage hepato-renal disease. 836 68

Primary hyperoxaluria (PH) type 1 and type 2 are autosomal recessive defects of oxalate metabolism resulting from glyoxylate accumulation which occurs by two distinct pathways. PH1 is associated to glycolic aciduria; PH2 to L-glyceric aciduria. Because hyperoxaluria leads to nephrolithiasis or nephrocalcinosis in both, they can be differentiated only through detection of the associated acidurias. However, glycolate and L-glycerate assays are not widely available and, in the setting of ESRF, diagnosis is hampered by a number of misleading events. At any stage of the disease diagnosis is crucial because there are differences between the two forms in clinical behaviour, long-term prognosis, and treatment. In this paper we outline diagnostic criteria for identification of PH2 in two patients, one with maintained renal function and one with ESRF on CPD, based on the use of a novel HPLC assay of L-glycerate in different body fluids. With the routine application of this procedure PH2 has been identified in two of 23 patients fulfilling criteria for diagnosis of PH. This suggests that the type 2 variant of PH may occur more frequently than so far suspected, and should be tested for even in the setting of ESRF.
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PMID:Detection of primary hyperoxaluria type 2 (L-glyceric aciduria) in patients with maintained renal function or end-stage renal failure. 853 30

Most cases of primary hyperoxaluria are due to deficiency of hepatic peroxisomal alanine:glyoxylate aminotransferase [i.e. primary hyperoxaluria type 1 (PH1), McKusick 259900] and several hundred examples have been described since the original report in 1925. By contrast, primary hyperoxaluria type 2 (PH2, McKusick 260000) is very rare indeed with only 22 patients recorded since the original description in 1968. PH2 is characterized by hyperoxaluria and L-glyceric aciduria and is caused by deficiency of D-glycerate dehydrogenase/glyoxylate reductase. In comparison with PH1 much less is known about PH2 and considerable uncertainties remain about its frequency, clinical course and optimum management.
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PMID:Primary hyperoxaluria type 2. 859 29

The introduction of renal ultrasound technology has shown renal calcification to be more common in infancy than was previously believed. Understanding the role of inhibitors and promoters in crystal formation helps elucidate the pathophysiology of nephrocalcinosis. Identification of the presence or absence of hypercalcemia and hypercalciuria is an effective way to direct the diagnostic work-up of infants with nephrocalcinosis. The sonographic image of renal calcification resolves spontaneously in many infants. Whether microscopic nephrocalcinosis persists below the threshold of ultrasonographic detection is unknown. Renal calcification can be associated with persistent renal function abnormalities if hypercalciuria continues, such as in VLBW infants who receive long-term furosemide therapy after discharge from the hospital. Renal calcification may also progress to renal failure, such as in infants with primary hyperoxaluria, owing to the persistence of hyperoxaluria, a potent promoter of calcium crystal formation.
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PMID:Renal calcification in the first year of life. 861 92


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