oxalates and Calcium-Metabolism-Disorders

Topics: Allopurinol; Calcium; Calcium Metabolism Disorders; Calcium Phosphates; Calcium, Dietary; Crystallization; Humans; Kidney Calculi; Magnesium Oxide; Oxalates; Phosphates; Pyridoxine; Recurrence; Thiazines; Uric Acid

Topics: Ammonia; Calcium Metabolism Disorders; Chemistry Techniques, Analytical; Cystinuria; Diagnosis; Humans; Kidney Calculi; Oxalates; Statistics as Topic; Surgical Procedures, Operative; Therapeutics; United States; Urine; Xanthines

A longitudinal 9-year retrospective study of 24-hour urinary calcium values has been made in a metabolic stone clinic amongst patients with idiopathic hypercalciuria. No seasonal variations could be observed in contrast ot a previous study from Leeds, A prospective longitudinal study was made of 24-hour urinary calcium values in a small group of normal subjects. No seasonal variation could be ovserved. In the prospective study no seasonal variations in urinary oxalate could be observed. In a 2-year longitudinal study of stone patients with idiopathic hypercalciuria, urinary oxalate was found to be higher in the summer than in the winter. This was attributed to the combination of a higher intake of oxalate-rich foods in the summer, and the low calcium diet with which they were treated.

Topics: Calcium; Calcium Metabolism Disorders; Clinical Trials as Topic; Humans; Longitudinal Studies; Oxalates; Prospective Studies; Retrospective Studies; Seasons

Topics: Calcium Metabolism Disorders; Child; Humans; Oxalates; Uric Acid; Urinary Calculi; Urinary Tract Infections

The probability of being a stone former (PSF) was calculated in 3 groups of idiopathic calcium stone formers [with normocalciuria (NC), dietary hypercalciuria (DH) and idiopathic hypercalciuria (IH)] in 4 conditions: while on a free diet; on a calcium- and oxalate-restricted diet during 4 days; after an oxalate load, while on a 1.5-gram calcium diet, and after an oxalate load while on a calcium-restricted diet. Combined calcium and oxalate restriction significantly decreased PSF only in NC and DH whereas the decrease was not significant in IH because of a concomitant significant increase in oxalate excretion. Increase of PSF with the oxalate load was significantly greater during a calcium-restricted diet than during the 1.5-gram calcium diet in all groups of patients (4, 6 and 12 times greater in NC, DH and IH, respectively). These data show the critical role of oxalate restriction when calcium is restricted in order to decrease the PSF. This combined restriction is however not sufficient in idiopathic hypercalciuric patients to decrease their PSF.

Topics: Calcium; Calcium Metabolism Disorders; Calcium, Dietary; Humans; Oxalates; Oxalic Acid; Risk; Urinary Calculi

Topics: Calcium Metabolism Disorders; Female; Humans; Kidney Calculi; Male; Oxalates; Oxalic Acid; Phosphates; Uric Acid

One hundred and twenty-four male stone formers with idiopathic hypercalciuria were followed up for 4 to 27 years (mean 12.2). Twenty-eight received restricted calcium diet alone, 52 also received bendrofluazide, 11 cellulose phosphate, and 33 received mixtures of those drugs. Although urinary calcium values fell in all groups, the stone recurrence rate remained unacceptably high. Patients on cellulose phosphate fared worst and this drug seems unsatisfactory as a sole agent. Urinary calcium was highest in patients without stone recurrences, but in patients with stone activity a higher stone recurrence rate was associated with higher urinary calcium and lower urinary volume.

Topics: Bendroflumethiazide; Calcium; Calcium Metabolism Disorders; Cellulose; Follow-Up Studies; Humans; Male; Oxalates; Oxalic Acid; Recurrence; Urinary Calculi

The effect of 1.25-dihydroxyvitamin D [1,25-(OH)2D] on dietary oxalate absorption and postprandial urine supersaturation with calcium oxalate was determined in 11 normal subjects. 1,25-(OH)2D increased the urinary excretion of orally administered [14C]oxalate in the 8 h period after a liquid meal containing 1.875 mmol of calcium and 0.83 mmol of oxalate (P less than 0.01), and during a 48 h period when the subjects ingested a diet containing 25 mmol of calcium and 3.3 mmol of oxalate/day (P less than 0.01); however, 1,25-(OH)2D administration had no effect on [14C]oxalate excretion when calcium was removed from the liquid meal. 1.25-(OH)2D increased 24 h urinary oxalate excretion from 28.7 +/- 2.1 mmol/mol of creatinine to 36.8 +/- 2.6 mmol/mol of creatinine (P less than 0.05) on the 10 mmol/day calcium diet and from 26.4 +/- 2.9 to 33.2 +/- 2.2 mmol/mol of creatinine (P less than 0.1) on the 25 mmol/day calcium diet. A linear correlation (r = 0.72) was found between plasma 1,25-(OH)2D levels and urinary [14C]oxalate excretion after the liquid meal. 1,25-(OH)2D administration produced postprandial supersaturation of urine with calcium oxalate and calcium oxalate crystalluria. These studies suggest that 1,25-(OH)2D increases oxalate absorption (and urinary excretion) by increasing calcium absorption, which results in less binding of calcium to oxalate in the intestine; therefore more oxalate is available for absorption. The combined effect of increased calcium and oxalate absorption results in postprandial supersaturation of urine with calcium oxalate, with resultant crystalluria.

Topics: Adult; Calcitriol; Calcium; Calcium Metabolism Disorders; Calcium Oxalate; Crystallization; Fasting; Female; Humans; Intestinal Absorption; Male; Osmolar Concentration; Oxalates; Oxalic Acid

Topics: Adolescent; Calcium Metabolism Disorders; Child; Child, Preschool; Humans; Magnesium; Oxalates; Uric Acid; Urinary Calculi

Eighty patients with proved calcium urolithiasis participated in an outpatient study designed to define the most likely metabolic problem related to the cause of the stone disease. Diagnostic categories included absorptive hypercalciuria (33 patients), renal leak hypercalciuria (20 patients), hypomagnesiumuria (27 patients), hyperuricemia and hyperuricuria (16 patients), hyperoxaluria (15 patients), normal stone-former (4 patients), renal tubular acidosis (2 patients) and suspicion of hyperparathyroidism (7 patients). Of the 80 patients 40 had more than 1 defect. Patients with a high suspicion of hyperparathyroidism were excluded from the study. Based on these criteria treatment plans incorporating medications, diet or both were instituted. Of 21 patients observed for greater than 2 years 90 per cent have shown no new stone disease.

Topics: Acidosis, Renal Tubular; Ambulatory Care; Calcium; Calcium Metabolism Disorders; Costs and Cost Analysis; Female; Humans; Hyperparathyroidism; Magnesium; Male; Outpatient Clinics, Hospital; Oxalates; Uric Acid; Urinary Calculi

Determining metabolic activity in urolithiasis may avoid excessive laboratory tests and unnecessary treatment. A simple regimen such as increased oral fluids is often effective therapy in metabolically inactive disease. Most cases of renal lithiasis are idiopathic, but a complete examination and laboratory work-up will usually establish an accurate etiologic diagnosis.

Topics: Aged; Calcium; Calcium Metabolism Disorders; Cystinuria; Humans; Male; Medical History Taking; Oxalates; Physical Examination; Radiography; Uric Acid; Urinary Calculi; Xanthines

The causes of hypercalciuria and simple diagnostic criteria for the various forms of hypercalciuria are outlined. Indications, effectiveness, limitations, and side effects of cellulose phosphate are described. Emphasis is placed on the biochemical pathogenesis and classification of hyperoxaluria. The problems of measuring and controlling oxalate excretion in patients with hyperoxaluria and calcium oxalate stones are discussed. Succinimide offers a partly successful approach to the reduction of endogenous oxalate synthesis.

Topics: Calcium; Calcium Metabolism Disorders; Cellulose; Glyoxylates; Humans; Organophosphorus Compounds; Oxalates; Phosphates; Succinimides; Urinary Calculi

The physicochemical factors involved in the formation of calcium-containing renal stones have been elucidated previously and some of the techniques for their quantitation are currently available. Accordingly, urinary activity product ratio (state of saturation), formation product ratio (limit of metastability), and crystal growth of brushite and calcium oxalate in 24-hr urine samples were compared between a control group without stones and stone-forming groups composed of patients with absorptive hypercalciuria, normocalciuric nephrolithiasis, and primary hyperparathyroidism. The activity product ratios of brushite and calcium oxalate were significantly elevated in stone-forming groups, largely because of the high renal excretion of calcium. The formation product ratios were reduced in most stone-forming groups, and the crystal growth was increased in the group with primary hyperparathyroidism. Thus, the physicochemical environment of urine in stone-forming groups was favorable to the nucleation of the nidi of brushite and calcium oxalate; in primary hyperparathyroidism, it may be conducive to the subsequent growth of nidi as well.

Topics: Adult; Calcium Metabolism Disorders; Calcium Phosphates; Crystallization; Female; Humans; Hyperparathyroidism; Kidney Calculi; Male; Oxalates

Topics: Calcium Metabolism Disorders; Glycolates; Humans; Ileum; Intestinal Diseases; Kidney Calculi; Liver; Oxalates; Postoperative Complications; Recurrence; Taurine

Topics: Amino Acids; Calcium Metabolism Disorders; Carbohydrate Metabolism; Diet Therapy; Drug Therapy; Humans; Infections; Metabolic Diseases; Oxalates; Uric Acid; Urinary Calculi

Topics: Acidosis, Renal Tubular; Alcohol Oxidoreductases; Allopurinol; Biopsy; Blood Urea Nitrogen; Calcium Metabolism Disorders; Disulfiram; Enzyme Repression; Glyoxylates; Humans; Kidney; Kidney Calculi; Kidney Failure, Chronic; Leukocytes; Nephrocalcinosis; Oxalates; Pyridoxine

Topics: Biochemical Phenomena; Biochemistry; Calcium Metabolism Disorders; Humans; Hyperparathyroidism; Kidney Calculi; Lithiasis; Metabolism; Oxalates; Uric Acid