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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of the kidney in states of hyperoxaluria and hypercalciuria was investigated in seven patients with hyperoxaluria after jejunoileal bypass (JIB) and six patients with idiopathic hypercalciuria (IHC). Eight apparently healthy persons formed a control group. Besides hyperoxaluria, the patients with JIB displayed an elevated plasma concentration of oxalate and the oxalate clearance was increased and higher than creatinine clearance, indicating a net tubular secretion of oxalate. The JIB patients had lower 24-h urinary excretions of calcium, phosphate, magnesium and citrate and higher serum parathyroid hormone (PTH) than controls, indicating increased secretion of PTH to compensate for calcium malabsorption. IHC patients exhibited increased fasting urinary calcium even though their serum values were similar to those in the controls. These results indicate a reduced tubular calcium reabsorption, which was most pronounced in patients with highest PTH values. We conclude that hyperoxaluria in JIB patients is associated both with intestinal hyperabsorption and with enhanced tubular secretion of oxalate, and that in some patients with IHC hypercalciuria is due to reduced tubular reabsorption of calcium.
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PMID:Hyperoxaluria or hypercalciuria in nephrolithiasis: the importance of renal tubular functions. 212 87

The authors studied the features of urolithiasis in three different geographical regions: Moscow, the Kirghiz SSR, and Berlin from the findings of examination of the composition and structure of uroliths removed by operation or passed spontaneously, (602 concrements from Moscow, 10,000 from Berlin, and 127 from Kirghizia). X-ray diffraction measurement, infrared spectrophotometry, and polarizing microscopy were conducted to analyze the composition and structure of the stones. Complex biochemical examination was carried out in patients from Moscow and Kirghizia. According to the results of the study, the following features of urolithiasis are common in the studied regions: (1) prevalence of oxalate lithiasis on the whole, which points to the principal role of metabolic factors in lithogenesis; (2) approximately similar amounts of apatite carbonate crystals in the uroliths; (3) certain similarity in composition of concrements from Berlin and Kirghizia. The most essential differences are: (1) the frequency of renal oxalate stones is highest in Berlin and lowest in Moscow. The prevalent types of calcium oxalate stones are: whewellite of concentric structure (linked with hyperuricemia) in Kirghizia; whewellite of small randomly orientated crystals (linked with hypercalciuria) and stones with signs of transformation of weddellite to whewellite in Moscow; (2) lesser distribution of phosphate lithiasis in Berlin than in Kirghizia and particularly in Moscow. Prevalence of struvite crystals in stones from Moscow, the formation of which is linked with the vital activity of Proteus and E. coli; (3) higher distribution of urate lithiasis in Moscow and particularly in Kirghizia where significant metabolic risk factors of lithogenesis were revealed.
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PMID:[The characteristics of the chemical composition and structure of urinary stones and their prevalence in the cities of Moscow, Berlin and of the Kirghiz SSR]. 214 36

Three patients with vitamin D-dependent rickets type II were given massive doses of 1 alpha-hydroxyvitamin D3 for 29 to 36 months and their calcium-phosphate balance was studied during treatment and one month after cessation of treatment. During treatment fasting hypercalciuria was observed in patient 1 and an increased rate of calcium excretion after calcium loading in patients 1 and 2. In these patients, calcium excretion was parallel with the serum 24,25-dihydroxyvitamin D concentration, which may reflect the level of receptor for 1,25-dihydroxyvitamin D. These findings suggested that the responsiveness to 1,25-dihydroxyvitamin D improved during long-term treatment of these two patients with vitamin D-dependent rickets type II.
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PMID:Effect of long-term treatment with massive doses of 1 alpha-hydroxyvitamin D3 on calcium-phosphate balance in patients with vitamin D-dependent rickets type II. 215 5

We performed 6-h human PTH-(1-34) infusions in 8 control subjects, 10 subjects with primary hyperparathyroidism, and 7 men with idiopathic hypercalciuria. We measured serum calcium, serum 1,25-dihydroxyvitamin D, urinary calcium, and fractional phosphate excretion. The PTH-induced rise in serum 1,25-dihydroxyvitamin-D was significantly smaller in the hyperparathyroid patients than in either the controls or the hypercalciuric patients. The rise in serum calcium was similar in all 3 groups. The hyperparathyroid subjects had higher basal fractional phosphate excretion than the other two groups. PTH failed to increase fractional phosphate excretion in the hyperparathyroid individuals, whereas there was a statistically significant increase in the other two groups. PTH was without significant effect on urinary calcium excretion in any of the three groups. There were no discernible differences between the responses of the hypercalciuric patients and those of the normal subjects. These findings suggest that while responses to PTH are normal in hypercalciuria, some hyperparathyroid patients are resistant to exogenous PTH. This resistance is limited to specific arms of the PTH response pathway and may not involve PTH receptors.
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PMID:Parathyroid hormone sensitivity in primary hyperparathyroidism and idiopathic hypercalciuria: effects on postadenylate cyclase parameters. 215 86

We studied 40 patients with calcium urolithiasis and idiopathic hypercalciuria in an attempt to identify patients with an absorptive or renal type of hypercalciuria. An oral calcium tolerance test was performed in all patients, resulting in a rise in serum calcium in all cases (2.35 +/- 0.09 mmol/l vs 2.49 +/- 0.09 mmol/l; P less than 0.001). This was also true for serum phosphate (0.96 +/- 0.17 mmol/l vs 1.09 +/- 0.18 mmol/l; P less than 0.001), TmPO4/GFR (0.95 +/- 0.19 mmol/l vs 1.20 +/- 0.25 mmol/l; P less than 0.001) and fasting calcium excretion (3.14 +/- 1.16 mmol/100 l GF vs 6.17 +/- 2.02 mmol/100 l GF; P less than 0.001). All patients showed a drop in nephrogenous cAMP excretion (1.33 +/- 0.95 nmol/dl GF vs 0.74 +/- 0.72 nmol/dl GF; P less than 0.001). iPTH levels declined significantly (2.70 +/- 1.50 pmol/l vs 2.11 +/- 1.19 pmol/l; P less than 0.001). However, discordant individual changes in suppression of nephrogenous cAMP excretion, and rises in fasting calcium excretion prohibited a distinction between the absorptive or renal type of hypercalciuria. It is concluded that an oral calcium tolerance test is not helpful in the choice of management of patients with idiopathic hypercalciuria.
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PMID:The usefulness of an oral calcium tolerance test in the choice of management of patients with idiopathic hypercalciuria. 216 24

The part played by hyperoxaluria in the formation of calcium oxalate urinary calculi was studied in 153 patients who had each been diagnosed as having calcium oxalate urinary calculi on one or more occasions. Seventy-seven of the patients excreted normal amounts of calcium (less than 6.2 mmol/d), and 76 had hypercalciuria (excretion greater than or equal to 6.2 mmol/d); each group was divided into a further two groups depending on whether the oxalate concentration was above or below 0.16 mmol/l. Pure calcium oxalate stones were more common in patients whose calcium excretion was normal, and mixed calcium oxalate and phosphate stones were more common among hypercalciuric patients. Urinary concentrations/day of magnesium, citrate, and phosphorus were significantly lower in the two groups in which the oxalate concentrations were below 0.16 mmol/l than in a normal control group, and magnesium and phosphorus were significantly lower in the two groups in which oxalate concentrations were less than 0.16 mmol/l than in the two in which they were above that value. The concentration of citrate was also lower, but not significantly so. In addition, the pH of the urine in patients with mixed stones was significantly higher in all groups than when the stones were composed of pure calcium oxalate.
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PMID:The role of hyperoxaluria in the formation of calcium oxalate urinary calculi, and its association with other biochemical measurements. 223 98

Nineteen children with clinical diagnoses of renal tubular acidosis were followed for periods ranging from 3 months to 20 years. Twelve patients had Type 1 renal tubular acidosis, five had Type 2, and two had Type 4. No sex predilection was found for any one of the types. Most patients had been diagnosed before 18 months of age, with failure to thrive the most common presentation. Tachypnea, polydipsia, polyuria, and vomiting were frequent symptoms. Some of these children had associated renal hypoplasia, vesicoureteral reflux, unilateral renal agenesis, glomerulocystic disease, adult polycystic kidney disease, and cyanotic congenital heart disease. Urinary anion gap may be useful for differential diagnosis of altered distal urinary acidification from other hyperchloremic metabolic acidosis. Furosemide test may need further investigation. Inability to raise urine to blood pCO2 gradient is helpful for diagnosis of Type 1 renal tubular acidosis. Hypokalemia, hypocalcemia, hypophosphatemia, decreased tubular reabsorption of phosphate, and hypercalciuria occurred in some patients. Complications included rickets in two, nephrocalcinosis in one, and episodic hematuria in one. There was relative bicarbonate wasting in children with Type 1 renal tubular acidosis, with a mean therapeutic bicarbonate requirement of 4.4 +/- 2.6 meq/kg/day. The mean bicarbonate dose for patients with Type 2 renal tubular acidosis was 8.3 +/- 2.6 meq/kg/day. Most children had good response to treatment with complete catch-up linear growth in 13, improved growth in 4, and continuing poor growth in 2. Two patients died during follow-up. Two other patients maintained normal growth without medication.
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PMID:Renal tubular acidosis in childhood. 226 80

A 29-year-old insulin-dependent diabetic woman developed phosphate depletion, nephrolithiasis and bilateral ureteric obstruction due to antacid abuse. Unlike previous descriptions of chronic phosphate depletion, myalgia, weakness and bone pain were absent. Biochemical features included hypophosphataemia, hypercalciuria, hypophosphaturia, elevated plasma, 1,25-dihydroxyvitamin D and low plasma intact parathyroid hormone. These abnormalities were corrected when antacid ingestion was reduced and phosphate intake supplemented. We propose that phosphate depletion secondary to antacid abuse caused 1 alpha-hydroxylase activation and elevation of the plasma 1,25-dihydroxyvitamin D level, leading to marked hypercalciuria. Once diagnosed, antacid abuse is a readily reversible cause of hypercalciuria and renal stones. Moreover, antacid-induced phosphate depletion may present with nephrolithiasis in the absence of musculoskeletal symptoms. This report is intended to draw attention to this important cause of renal stone disease.
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PMID:Antacid-induced phosphate depletion syndrome presenting as nephrolithiasis. 229 30

In a retrospective study, 760 Saudi patients with urolithiasis were epidemiologically and metabolically studied (41% were from the Central region, 32% South, 14% West, 9% North, and 1% East; the remaining 3% were Saudi but of unknown region). The male to female ratio was 5:1; 87 percent of the patients were aged thirty to sixty years and 11 patients were under age fourteen. There was no clear relation of stone formation to occupation. Sixty-nine percent of calculi were renal, 29 percent ureteric, and only 3 percent were bladder calculi. Two hundred seventy-eight operative procedures were done (36.5% of all patients), including pyelolithotomy, nephrolithotomy, ureterolithotomy, ESWL, cystolithotomy, and extractions by basket. Infection was a rarity (6%) and urinary schistosomiasis was found in 33 patients (4.3%), 24 of whom were from a schistosoma-infested region. Raised serum calcium was found in only 5.7 percent and raised serum urate in 13 percent. Increased urinary excretion of urate was found in 60 percent and hypercalciuria in 9 percent. Seventy-six percent of stones analyzed (239) were calcium oxalate, 20.5 percent urate, and 3.3 percent phosphate.
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PMID:Urolithiasis in Saudi Arabia. 229 13

In calcium oxalate urolithiasis, the monohydrate and dihydrate forms can be found. The aim of this paper is to examine a group of patients with calcium oxalate calculi to determine the calcium oxalate form and the possible relationship with calcium and other urinary biochemical parameters. It was found that calcium oxalate monohydrate is more frequent in the normocalciuric group and also is associated with a lack of inhibitory capacity, while a mixed calculus of calcium oxalate and phosphate or calcium oxalate dihydrate can be related with hypercalciuria.
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PMID:Relation between calcium oxalate hydrate form found in renal calculi and some urinary parameters. 230 91


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