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

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.
 ...
PMID:The role of hyperoxaluria in the formation of calcium oxalate urinary calculi, and its association with other biochemical measurements. 223 98

We have evaluated the urinary excretion of promoting (calcium, phosphorus, uric acid, oxalate) and inhibiting (citrate, magnesium, glycosaminoglycans) factors of crystallization in subjects with idiopathic hypercalciuria and calcium urolithiasis and in a control group. The examined children had a free diet and were drug free for the last 2 weeks. They were not affected by malabsorption, D-RTA, urinary tract infection, or urinary tract malformation (factors interfering with urinary excretion of citrate and oxalate). In the patients with calcium urolithiasis, the daily urinary excretion of oxalate was significantly higher (p less than 0.01), and the urinary excretion of citrate was significantly lower (p less than 0.001) than in the subjects with idiopathic hypercalciuria and in the control group. Among the subjects with idiopathic hypercalciuria, those aged 4-9 years had a significantly reduced, though in the normal range, urinary excretion of citrate as compared with those aged 10-15 years (362 +/- 189 and 503 +/- 198 mg/g creatinine/24 h, respectively; p less than 0.01). Our data show that hypocitruria may play an important role in the pathogenesis of urolithiasis in children with idiopathic hypercalciuria. In these cases, the urinary citrate excretion was not inversely related to age, as has been suggested by other authors.
 ...
PMID:Promoters and inhibitors of calcium urolithiasis in children. 225 56

A prospective multicenter study was designed to determine the frequency and prognostic importance of hypercalciuria in children with hematuria. Urinary calcium excretion was examined in 215 patients with unexplained isolated hematuria (no proteinuria, urolithiasis, infection or systemic disorder). Hypercalciuria (urinary calcium excretion greater than 4 mg/kg/day) was identified in 76 patients (35%). Compared to patients with normal urinary calcium excretion, children with hematuria and hypercalciuria were characterized by male preponderance, white race, family history of urolithiasis, gross hematuria and calcium oxalate crystals. Renal biopsies were performed in 10 patients with urinary calcium excretion 0.4 to 2.5 mg/kg/day; three had IgA glomerulonephritis, three had glomerular basement membrane thinning, one had proliferative glomerulonephritis and three were normal. Renal biopsies in three patients with hypercalciuria showed focal segmental glomerulosclerosis, hereditary nephritis or no abnormalities. Oral calcium loading tests showed renal hypercalciuria in 26 patients, absorptive hypercalciuria in 15 patients and were not diagnostic in 35 patients. Serum parathyroid hormone, bicarbonate and phosphorus and urinary cyclic adenosine monophosphate concentrations were similar in the three groups of hypercalciuric patients. Urinary calcium excretion after one week of dietary calcium restriction was higher (5.8 mg/kg/day) in renal hypercalciuria than in other hypercalciuric patients (3.4 mg/kg/day), P less than 0.01. One to four years follow-up was available for 184 patients. Eight of 60 hypercalciuric patients developed urolithiasis or renal colic compared to 2 of 124 patients with normal urinary calcium excretion (P less than 0.001). Hypercalciuria is commonly associated with isolated hematuria and represents a risk factor for future urolithiasis in children with hematuria.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Idiopathic hypercalciuria: association with isolated hematuria and risk for urolithiasis in children. The Southwest Pediatric Nephrology Study Group. 240 91

The occurrence of acetylation phenotype has been studied in 76 patients with untreated hyperthyroidism. In 23 of these patients having the "fast" and in 42 having the "slow" acetylation phenotype the selected parameters of calcium-phosphate metabolism have been determined before, during and after propranolol therapy lasting six days. Propranolol was administered at a dose of 160 milligrams daily. A significant decrease in the blood serum level of calcium and urinary calcium excretion following propranolol administration was found only in patients with hypercalcemia and hypercalciuria. On the other hand, a significant decrease in the urinary excretion of hydroxyproline was observed in all the patients with hyperthyroidism treated with propranolol. The effect of propranolol on the measured parameters of calcium-phosphorus metabolism was similar in hyperthyroid patients with both "fast" and "slow" acetylation phenotypes, what suggests that it does not depend on the N-acetyltransferase activity.
 ...
PMID:[Acetylation phenotype and the changes in selected indicators of calcium-phosphate metabolism in patients with hyperthyroidism treated with propranolol]. 248 31

The effect of dietary phosphorus (P) on calcium (Ca) and phosphorus metabolism was studied in young female rats. P levels in the semipurified diets ranged from 0.1 to 0.4% (w/w). A level of 0.4% P in the diet is recommended for rats. Kidney calcification was observed in rats fed the 0.4%-P diet whereas P restriction prevented this condition. Rats fed the diet containing 0.1% P, showed severe hypercalciuria, hypercalcemia, reduced growth and impaired bone mineralization. These effects did not occur when the diet contained 0.2 or 0.3% of P. This study suggests that in short-term studies P in the diet of female rats can be restricted to 0.2% so as to prevent nephrocalcinosis without affecting their development.
 ...
PMID:Influence of dietary phosphorus restriction on calcium and phosphorus metabolism in rats. 252 16

Investigation of 44 patients with endogenous hypercorticism (EH) of various degrees of severity showed that the development of osteoporosis was accompanied by changes in the indices of calcium-phosphorus metabolism and calcium regulating hormones. Marked variations in the level of parathyroidin, calcitonin, vitamin D3 were observed in a severe type of EH. All the examinees were characterized by a decrease in the transport form of vitamin D3, which was most noticeable in a mild form of EH. A significant decrease in the concentration of the transport form of vitamin D3 against a background of hypercalcemia and hypercalciuria in mild EH can be regarded as the most informative indicators in early diagnosis of initial symptoms of osteoporosis.
 ...
PMID:[Calcium-regulating hormones in endogenous hypercorticism]. 254 55

Aminoaciduria and secondary hyperparathyroidism accompany vitamin D deficiency. However, the degree of aminoaciduria and PTH elevation have not been studied relative to different calcium and phosphorus dietary intakes. Weanling rats were fed 5 vitamin D deficient diets for 4-6 weeks: very low Ca (VLC) 0.02% Ca, 0.3% P; VLC + 1,25-dihydroxyvitamin D [1,25(OH)2D3], same + 500 pmol i.p. for 2 days; low Ca (LC) 0.45% Ca, 0.3% P; very low P (VLP) 1.2% Ca, 0.1% P; high Ca (HC) 2.5% Ca, 0.3% P, and control 1.2% Ca, 0.70% P + 2.5 micrograms% vitamin D. Amino acids, serum 25-hydroxyvitamin D [25(OH)D3], 1,25(OH)2D3, and PTH, using a specific antirat PTH antibody, were measured. A significant generalized aminoaciduria (11 amino acids) was found in all vitamin D-deficient groups. Furthermore, it was independent of plasma Ca and PTH, and urinary cAMP excretion irrespective of diet. Serum 25(OH)D and 1,25(OH)2D were significantly reduced in all vitamin D-deficient groups. VLC and VLC + 1,25(OH)2D3 were associated with the highest PTH levels (10- and 13-fold increase, respectively) and urinary cAMP (2.3-fold increase in each) and the lowest serum Ca. LC rats had an 8.8- and a 1.7-fold increase in PTH and urinary cAMP, respectively. Phosphate depletion was found in VLP rats documented by insignificantly elevated PTH, normal urinary cAMP, hypercalciuria, and percent tubular reabsorption of phosphate of greater than 99%. While dietary Ca and P affect plasma and urinary Ca and P plasma PTH and urinary cAMP, it appears that dietary P affects the aminoaciduria observed in this study via mechanisms that remain unclear. The possibility that the mechanism for the tubulopathy is multifactorial should be entertained.
 ...
PMID:Aminoaciduria of vitamin D deficiency is independent of PTH levels and urinary cyclic AMP. 254 72

This study was conducted to determine the effect of a high protein diet on calcium metabolism in rat. Wistar strain male rats (50 days old) were divided into 5 groups (day 0): control diet (18% casein); high protein diet (18% casein +20% lactalbumin); high protein and 0.1% sodium bicarbonate diet; high protein and 0.2% sodium bicarbonate diet; and high protein and 0.4% sodium bicarbonate diet. On days 0, 1, 3, 5, 7, 9, urine samples were collected and, at the same time, feces were collected from half of the animals in each group. Urinary titratable acidity (TA-HCO3-), ammonium ion (NH4+), and net acid excretion (NAE) were measured as an index of acid-base balance in rat body. Urinary volume was rapidly increased and the increase of urinary volume continued throughout the study in rats fed the high protein diet. Urinary excretions of calcium and phosphorus were increased after day 3 and day 1, respectively, in rats fed the high protein diet. The high protein diet depressed calcium absorption and elevated phosphorus absorption from the digestive tract in rats fed the high protein diet. The high protein diet decreased TA-HCO3-, which was closely correlated with the decrease of NAE. Sodium bicarbonate supplementation to the high protein diet had little effect on urinary calcium excretion and NAE. This study suggested that there was no relationship between metabolic acidosis and hypercalciuria in rats fed the high protein diet.
 ...
PMID:Effects of high protein diet and sodium bicarbonate supplementation on calcium metabolism in rats. 263 82

33 normocalcemic patients (22 males and 11 females) aged 20-68 years with recurrent renal stone formation and idiopathic hypercalciuria were compared to 33 approximately sex- and age-matched normal controls. Quantitative histomorphometric analysis of iliac crest biopsies were performed after intravital tetracycline double labeling in the patients and in 30 sex- and age-matched normal controls. No difference was found between patients and controls in albumin adjusted serum calcium levels. Serum phosphorus was significantly reduced (p less than 0.01) in the patient group whereas the urinary phosphorus/creatinine ratio was increased (p less than 0.01). The serum calcium phosphate product (S-CaxS-P) was significantly reduced in the patients (p less than 0.05). As expected, the urinary calcium/creatinine ratio was higher in the patient group than in the controls (p less than 0.001). Serum parathyroid hormone was normal. The histomorphometric analysis revealed signs of a moderate mineralization defect (reduced adjusted appositional rate (p less than 0.05), prolonged mineralization lag time (p less than 0.05) and prolonged formation (p less than 0.05)), and an increased extension of eroded surfaces (P less than 0.05) in the patients. The amount of trabecular bone and the balance between the thickness of bone resorbed and later formed per remodeling cycle and all other histomorphometric parameters were found normal in the patients. The combined histomorphometric and biochemical data are best explained by a primary renal phosphate leak leading to hypophosphataemia and a slight mineralization defect. The hypercalciuria may be explained by an enhanced renal production of 1.25-dihydroxyvitamin D secondary to the reduced serum levels of phosphorus. No signs of secondary or primary hyperparathyroidism were observed.
 ...
PMID:A histomorphometric determination of iliac bone remodeling in patients with recurrent renal stone formation and idiopathic hypercalciuria. 271 52

The study deals with 13 healthy controls with normal basic indices for calcium-phosphorus metabolism and 25 patients with recurrent calcium nephrolithiasis and hypercalciuria, 13 of them with renal hypercalciuria and 12 patients with absorptive hypercalciuria. The oral calcium-tolerance test was carried out in all persons. The changes in the serum and urine calcium and magnesium concentrations following the calcium loading are recorder. A statistically significant increase of magnesium urine excretion was found in all persons examined, the highest being in the patients with renal hypercalciuria, considerably higher than in the healthy controls. The conclusion is reached that the magnesium urine excretion gives valuable information for the diagnosis of patients with renal hypercalciuria.
 ...
PMID:[The effect of oral calcium loading on the serum magnesium concentration and its urinary excretion in patients with recurrent calcium nephrolithiasis and hypercalciuria--differential diagnostic potentials]. 274 43


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>