Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic administration of lithium salts is associated with hypercalciuria in the rat. To study the renal and extrarenal mechanisms of this phenomenon, we utilized balance and clearance techniques in rats pair-fed diets with or without Li2CO3 (0.5 meq/day per rat). Lithium induced hypercalcemia (mean +/- SE: 5.40 +/- 0.09 VS. 5.06 +/- 0.05 meq/liter) and hypercalciuria (Ca/creatinine = 0.28 +/- 0.04 vs. 0.13 +/- 0.03) only during feeding. When CaCO2 supplement to a calcium-deficient diet was abruptly withdrawn, hypercalciuria was abolished. However, polyuria and polydipsia persisted. No significant changes in serum phosphate, urine phosphate, sodium, pH, or citrate were observed. Chronic parathyroidectomy (PTX) also abolished this effect. During clearance studies, fasting excretion of calcium was similar between treated and control animals. Superimposed acute PTX resulted in comparable changes, hence arguing against primary changes in renal calcium reabsorption or changes in parathyroid hormone effects on the renal tubule. Thus, lithium produces absorptive hypercalciuria by a mechanism dependent on intact parathyroid glands and adequate diet calcium, but independent of urine sodium, phosphate, or pH. The active component of gut calcium transport may be involved, possibly via alterations of vitamin D metabolism.
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PMID:Mechanism of lithium-induced hypercalciuria in rats. 62 44

The effects of phosphate depletion on magnesium (Mg) homeostasis were evaluated in rats fed a diet containing 0.03% phosphorus for periods up to 8 wk. Plasma phosphorus fell significantly (P < 0.01) from 10.1+/-0.27 (SE) to 5.0+/-0.54 mg/100 ml within 1 day and continued to fall gradually to a level of 1.2+/-0.21 mg/100 ml by the end of the 8th wk. A significant (P < 0.01) increment in urinary Mg excretion (UMgV) from 46+/-2.7 to 126+/-24 mueq/24 h occurred during the 1st day of phosphate depletion; UMgV reached a peak of 300+/-24 mueq/24 h by the 3rd day and remained high ranging between 150-300 mueq/24 h, thereafter. The magnitude of the magnesuria was related to the degree of hypophosphatemia and was not affected by lowering the calcium intake and reducing the hypercalciuria. The concentration of plasma Mg fell significantly (P < 0.01) from 1.2+/-0.02 to 0.79+/-0.10 meq/liter by the 1st day of the study and remained low throughout.Mg balance became negative during the 1st day of phosphate depletion and remained so during the entire study. This occurred despite a significant increment in the fraction of ingested Mg absorbed which became evident by the 3rd wk of phosphate depletion. Mg content of muscle, kidney, and liver were not affected but bone Mg was reduced significantly. The change in bone Mg was not due to an overall reduction in bone mineral content because bone calcium content was not affected. Supplementation of large amounts of Mg (800-1,000 mueq/day) in the drinking water produced a normalization of serum Mg but did not bring about restoration of bone Mg despite a positive Mg balance. The disturbances in Mg metabolism were independent of the age or weight of the animals. Our results indicate that phosphate depletion is associated with (a) magnesuria due to a decrease in the net renal tubular reabsorption of Mg with the main source of the urinary losses being bone Mg; (b) hypomagnesemia secondary to the renal leak of Mg; (c) negative Mg balance; and (d) increase in the intestinal fractional absorption of Mg. The latter was not adequate to compensate for the urinary losses of Mg.
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PMID:Effect of phosphate depletion on magnesium homeostasis in rats. 64 Nov 38

A 36-year-old woman suffered from bone pain, muscle weakness, and renal stones after prolonged ingestion of antacids for esophageal reflux. Investigation disclosed hypophosphatemia, hypercalciuria, and osteomalacia by bone biopsy. All symptoms and abnormal laboratory findings reversed with a regimen of oral phosphate supplementation and cessation of antacid intake.
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PMID:Antacid-induced osteomalacia and nephrolithiasis. 64 54

Fifteen patients, 13 women and 2 men (mean age 60 years) with osteoporosis of different types have been under treatment with 1 alpha-hydroxyvitamin D3 and calcium. The responses were observed clinically and by the use of roentgen morphometry, photon absorptiometry and by blood and urine chemical analyses. The treatment had beneficial clinical effect in all but 3 patients. The intestinal calcium absorption rate increased significantly. Slight hypercalcemia and a significant hypercalciuria occurred during treatment. Serum and urine phosphate levels, alkaline phosphatase and parathyroid hormone values were within normal ranges. The bone mineral content increased significantly during treatment. 1 alpha-hydroxyvitamin D3 and calcium was well tolerated by the patients. Three patients had coincidental acute attacks of spinal pain and 2 had further vertebral crush fractures. A period of time longer than one year is necessary to further evaluate the effects of 1 alpha-hydroxyvitamin D3 therapy on the clinical course of severe osteoporosis.
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PMID:Interim report on treatment of osteoporotic patients with 1 alpha-hydroxyvitamin D3 and calcium. 70 36

Absorptive hypercalciuria was treated in 27 patients with cellulose phosphate. In all patients urinary calcium decreased and stone formation virtually ceased. The most striking side effect was an excessive hyperoxaluria, necessitating withdrawal of the drug in 8 patients. Succinate decreased the hyperoxaluria in 14 of 19 patients. All patients had mild hypercalciuria and hypermagnesiuria. This study was done to determine the therapeutic value and the side effects in the treatment of absorptive hypercalciuria with sodium cellulose phosphate and of hyperoxaluria with succinate.
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PMID:Calcium oxalate stone disease: effects and side effects of cellulose phosphate and succinate in long-term treatment of absorptive hypercalciuria or hyperoxaluria. 73 12

13 patients presenting with immobilization stones are reported. Young males with an infection of the urinary tract are most commonly affected. In the case of phosphate stones, the infection of the urinary tract with an alkaline shift of the pH and an idiopathic hyperuricosuria play a decisive part together with temporary hyperphosphaturia and hypercalciuria. The importance of urea splitting bacteria in the urine for stone formation is stressed. Applied in time increase of fluid intake, specific antibiotics and allopurinol can lead to litholysis. If the urine of immobilized patients were monitored closely from the beginning of the hospitalisation for the above factors, and treated appropriately, urine calculi should be largely prevented.
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PMID:Renal calculus dissolution in immobilized patients. 73 1

In a double-blind controlled clinical study, 71 patients with recurrent calcium oxalate stones were divided into three treatment groups: those who received potassium acid phosphate, those who received an inert placebo, and those who received a low calcium diet only. Follow-up periods averaged 2.9 years. Although the mean urinary calcium level of the patients who received phosphate was reduced 33 per cent, their renal stone disease did not diminish. Mean urinary phosphorus increased 88 per cent with phosphate treatment but did not correlate with the decrease in urinary calcium, or with treatment success. The data did not suggest that phosphorus and its metabolites retard calcium oxalate crystallization in urine. No evidence appeared for an association of hypercalciuria with severe stone disease, or with a specific clinical or chemical response to phosphate therapy. Patients whose urinary calcium level fell more than 25 percent when dietary calcium was reduced may have excessive gastrointestinal calcium absorption, which appears to be associated with improved chemical response to phosphate therapy.
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PMID:Recurrent nephrolithiasis: natural history and effect of phosphate therapy. A double-blind controlled study. 78 40

The effects of chronic phosphate depletion on renal tubular function were evaluated by micropuncture and free water clearance studies in the dog. Proximal tubular punctures demonstrated that chronic hypophosphatemia led to a reduction in ratio of tubular fluid to plasma inulin in late superficial tubular from 1.59+/-0.08 in control animals to 1.29+/-0.06 in phosphate-depleted dogs, with proportional inhibition of calcium and sodium reabsorption. The chronic decrease in proximal tubular fluid reabsorption was confirmed by the analysis of sustained water diuresis in conscious, phosphate-depleted dogs, before and after repletion of body PO4 stores, and in control animals. Urine flow rate/100 ml glomerular filtration rate (V/GFR) was significantly higher in PO4 DEPLETION THAN CONTROL (15.8+/-1.1 VS. 10.7+/-0.82). In addition, acetazolamide infusion did not increase V/GFR in phosphate-depleted dogs (15.8+/-1.1 vs. 17.16+/-0.9), supporting the conclusion that inhibition of proximal tubular fluid reabsorption was responsible for the elevated urine flow rate. PO4 repletion over 5 days reduced V/GFR to 9.2+/-0.7 despite no change in urine osmolality and no change in GFR, further suggesting a specific reversible alteration in proximal tubular reabsorption in phosphate depletion. Although hypercalciuria was a constant finding in phosphate depletion (fractional excretion of calcium of 2.04+/-0.4% vs. 0.47+/-0.13% in controls), the enhanced distal delivery of calcium was not a crucial factor; acute phosphate infusion reduced urinary calcium excretion to control values without affecting the reduced proximal tubular reabsorption in either intact or thyroparathyroidectomized phosphate-depleted dogs the change in distal nephron calcium reabsorption was independent of parathyroid hormone (PTH) levels since infusion of PTH failed to alter urinary calcium excretion. We conclude that chronic phosphate depletion leads to a reversible, sustained inhibition in proximal tubular reabsorptive fuction as well as a specific decrease in distal nephron calcium reabsorption. This latter reabsorptive defect is sensitive to phosplate infusion but not corrected by PTH.
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PMID:Renal tubular effects of chronic phosphate depletion. 85 68

Individual urine samples from normal subjects and stone-formers with idiopathic hypercalciuria have been examined for crystals both qualitatively and quantitatively at 37 degrees C. The group as a whole showed a rise in incidence of urinary crystals in the summer months of June to August inclusive. This rise was seen most clearly in overnight urines, collected on rising in the morning, and the patients appeared to be at risk overnight during the summer. In the untreated patients the summer rise in incidence of phosphate crystals was quite dramatic but was only small in the cellulose phosphate treated group, who showed a rather constant and raised incidence of oxalate crystals right through the year. Seasonal crystal incidence has been compared with seasonal changes in urinary composition. The rise in crystal incidence during the summer was associated with increased creatinine concentration in the same urine samples and with increased oxalate concentration in 24-hour urine collections.
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PMID:Seasonal variations in urinary crystals. 91 53

Sham-operated and parathyroidectomized (PTX) rats were divided into two pair-fed groups, one on a normal mineral intake (0.5% Ca, 0.3% P), the other on a regimen low in phosphorus (0.5% Ca, 0.03% P). P depletion led to a drop in plasma P and urine P, a rise in plasma Ca and a marked rise in urine Ca, a drop in serum magnesium and a rise in urine Mg. The changes were more pronounced in the PTX animals, but final values were the same in both groups. Parallel bone-seeking isotope (85Sr, 177Lu, 237Np) studies in nonablated animals revealed an increase in the urinary nuclide output and in the urine/tibia ratio in P-deficient animals. Normal and primary bone osteocytes decreased and enlarged osteocytes increased as a result of P deficiency; osteoclasts and osteoblasts also increased. Bone composition showed a drop in ash content and a rise in water, with a light decrease in both Ca and P, and a corresponding rise in hydroxyproline and nitrogen in the P-deficient animals. The results are interpreted to mean that P-deficiency in the young growing rat leads to an increase in bone resorption which occurs also in the absence of parathyroid hormone (PTH). The fact that final values were similar in the control and PTX P-deficient animals suggests that steady-state regulation can also occur without PTH. Because P-deficiency leads to rapid hypercalcemia and rapid marked hypercalciuria, there may exist a mechanism for phosphate regulation which would then supersede Ca homeostasis. The change in serum and urine Mg levels may reflect a decrease in tubular Ca and Mg reabsorption associated with P-deficiency.
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PMID:Phosphorus deficiency, parathyroid hormone and bone resorption in the growing rat. 95 82


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