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

The relationship between bone mineral status and hypercalciuria is controversial. The effect on bone composition of different forms of hypercalciuria was studied in female rats made hypercalciuric by 7-week administration of oral furosemide (F, n=12), intraperitoneal 1,25-dihydroxy vitamin D (VD, n=11), or oral ammonium chloride (AC, n=12). Seven untreated rats served as controls (C). Hypercalciuria (mg/100 g per 24 h, mean +/-SEM) of F (4.3+/-0.2), VD (4.1+/-0.4), and AC (3.9+/-0.3) groups was of similar intensity (C rats 1.3+/-0.1, P<0.01). Weight and length gains and serum CO2, sodium, potassium, calcium, and phosphate were no different among the four groups. Bone was studied by dual-energy X-ray absorptiometry of left tibiae. AC rats had significantly less bone area (1.505+/-0.018 cm2) than VD and C (1.602+/-0.020 and 1.587+/-0.019 cm2). Bone mineral content was decreased in F (0.357+/-0.007 g) and AC (0.362+/-0.006 g) compared with VD (0.407+/-0.008 g) and C (0.389+/-0.009 g) groups. Bone mineral density was different between F (0.231+/-0.002 g/cm2) and VD and C rats (0.254+/-0.004 and 0.245+/-0.003 g/cm2), and also between AC (0.240+/-0.003 cm2) and VD rats. In these rat models, hypercalciuria of renal origin (F) and hypercalciuria caused by acid load (AC) adversely impaired bone mass.
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PMID:Influence of three different types of hypercalciuria on bone. An experimental study. 1041 59

The careful analysis of cystine calculi may be important to detect the presence of other urinary alterations (such as hyperuricosuria, hypercalciuria, hyperoxaluria or bacterial infections) that coexist with cystinuria in many patients. For this reason, in the present study, 14 human and 17 canine cystine uroliths have been studied by infrared spectroscopy (IR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). According to the infrared analysis, most of the human and canine stones were composed of nearly pure cystine. However, in these calculi of apparently pure cystine, the study by SEM and EDX showed in many cases the presence of small amounts of calcium apatite. The infrared study of several samples heated at 750 degrees C confirmed the presence of phosphate, when it was difficult to detect this component in the spectra of the original samples owing to band overlapping. Other components detected in varying proportions in cystine calculi were magnesium ammonium phosphate hexahydrate (struvite), calcium hydrogen phosphate dihydrate (brushite), calcium oxalate (mono and/or dihydrate) and, in one case, a drug (oxolinic acid).
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PMID:Spectroscopic and ultrastructural comparative study of cystine calculi in humans and dogs. 1047 54

The composition of urinary stones in children depends on socioeconomic conditions and hygiene, geographical area, and dietary habits. We analyzed urinary stones from 120 consecutive Tunisian children (81 males, 39 females) aged 5 months to 15 years. The stone was located in the upper urinary tract in 91 cases (76%). Stone analysis included both a morphological examination and an infrared analysis of the nucleus and the inner and peripheral layers. The main components of bladder calculi were whewellite (69%) and struvite (22%), whereas the main component of upper urinary tract calculi was whewellite (67%). The nucleus of bladder stones was composed of ammonium urate (45%), struvite (28%), cystine (10%), and carbapatite (7%). The nucleus of kidney and ureteral calculi was mainly composed of ammonium urate (38%), whewellite (24%), carbapatite (13%), or struvite (11%). Based on stone composition, urinary tract infection was involved in the nucleation or growth of a third of calculi. Endemic urolithiasis involving simultaneous nutritional, metabolic, and infectious factors, and defined by its nucleus composed of ammonium urate without struvite, represented 40% of cases. Exclusive metabolic factors - including genetic diseases such as primary hyperoxaluria, cystinuria, and hypercalciuria - were responsible for less than 25% of cases.
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PMID:Urolithiasis in Tunisian children: a study of 120 cases based on stone composition. 1060 49

Calbindin D28k has been reported to be involved in the transcellular calcium transport along the rat distal tubule. It has also been shown that chronic metabolic acidosis (CMA) induces significant hypercalciuria. The present study investigated whether CMA affects the mRNA and the protein expression of calbindin D28k along isolated distal tubule (DT) of rats. The animals were made acidotic by adding 0.28 mol/L NH4Cl to the drinking water for 7 d. This maneuver was associated with an increase in plasma ionized calcium. Inulin clearance experiments demonstrated that metabolic acidosis did not affect GFR, but it significantly increased both total and fractional urinary calcium excretion. To define the role of calbindin D28k, total RNA was extracted from DT, identified, and microdissected from collagenase-treated kidneys. cDNA was synthesized from RNA using reverse transcriptase and oligo(dT)(12-18) primers. Calbindin D28k mRNA abundance was semiquantified by a competitive reverse transcription-PCR, using an internal standard of cDNA that differed from the wild-type calbindin D28k by a deletion of 86 bp. The reverse transcription-PCR was performed starting from the same amount of total RNA. For each set of experiments, control and acidotic rats were studied in parallel. The identity of the DT was further verified by the presence of the thiazide-sensitive NaCl cotransporter (rTSC1) mRNA. Calbindin D28k mRNA abundance was 0.89 +/- 0.21 amol/ng total RNA in DT of CMA rats (n = 5) compared with 0.30 +/- 0.12 amol/ng total RNA of control rats (n = 5) (P < 0.05). Using specific rabbit polyclonal anti-calbindin D28k antibody, Western blotting was performed starting from thin slices of outer cortex. Densitometric analysis revealed that in acidotic rats (n = 7) there was a 17 +/- 5% (P < 0.05) increase in calbindin D28k protein abundance compared with controls (n = 7). These results indicate that in the rat, ammonium chloride loading induces an increase in filtered ionized calcium load that is associated with a significant upregulation of calbindin D28k both at the mRNA and protein level. These last effects will help to reduce the concomitant hypercalciuria, thus mitigating the consequence of CMA on calcium metabolism.
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PMID:Effect of chronic metabolic acidosis on calbindin expression along the rat distal tubule. 1066 27

Stone disease is as old as recorded history but despite advances in diagnosis and treatment, it continues to cause significant morbidity. This review summarises the current pharmacologic management of urinary calculi based upon the stone type. All patients with stone disease are advised to increase fluid intake, limit dietary protein and limit sodium. Calcium oxalate stones can be managed on a selective or non-selective basis depending on the cause of the hypercalciuria or hyperoxaluria. Agents currently in use include sodium cellulose phosphate, thiazides, orthophosphates, oral calcium supplements, pyridoxine, cholestyramine, citrate, magnesium and allopurinol. Classically, struvite stones occur in the presence of urea splitting organisms and are composed of magnesium, ammonium phosphate and carbonate apatite. The goal of treatment is to make patients stone free as bacteria retained in stone fragments lead to stone growth. Urease inhibitors, aluminium hydroxide gel, hemiacidrin, and Suby G and M solutions are infrequently used in treatment. Cystine stones are the result of an autosomal recessive disorder. D-Penicillamine, captopril and alpha-mercaptopropionylglycine (MPG) are all oral agents that have proven to be efficacious. As more randomised trials are conducted and the understanding of endogenous stone inhibitors progresses, the medical management of stone disease will continue to improve.
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PMID:Pharmacology for renal calculi. 1124 28

Crystalluria is a marker of urine supersaturation present in both normal and pathological conditions. Indeed, nature and characteristics of the spontaneous crystalluria are of clinical interest for detecting and following biological disorders involved in renal diseases. Method. Crystalluria examination should preferably be performed on first morning urine or fresh fasting voiding samples by polarised microscopy in a Malassez cell. Urine samples must be stored at 37 degrees C or at room temperature and examined within two hours following voiding. Results and discussion. Crystalluria should be interpreted according to various criteria: 1) chemical nature of crystals for abnormal crystals such as struvite, ammonium urate, cystine, dihydroxyadenine, xanthine or drugs; 2) crystalline phase of common chemical species as calcium oxalates, calcium phosphates and uric acids; 3) crystal morphology (calcium oxalates); 4) crystal size (calcium oxalates); 5) crystal abundance (calcium oxalates, calcium phosphates, uric acids, cystine); 6) crystal aggregation (calcium oxalates); 7) frequency of crystalluria assessed on serial first morning urine samples, a very useful tool for long-term surveillance of patients. Within calcium oxalate crystalluria, presence of whewellite is a marker of elevated oxalate concentration (urine oxalate > 0.3 mmol/L); a crystal number > 200/mm 3 is highly suggestive of heavy hyperoxaluria of genetic or absorptive origin. Predominant weddellite crystalluria is most often indicative of an excessive urine calcium concentration (> 3.8 mmol/L); a dodecahedric aspect of the crystals is a marker for heavy hypercalciuria (> 6 mmol/L) while an increased crystal size (>or= 35 microm) is indicative of simultaneous hypercalciuria and hyperoxaluria. Calculation of the global crystal volume, especially when applied to calcium oxalates or cystine, is a clinically useful tool for the monitoring of patients suffering from primary hyperoxaluria or cystinuria. Lastly, presence of crystalluria in more than 50% of serial first voided morning urine samples is in our experience the most reliable biological marker for detecting the risk of stone recurrence in lithiasic patients. Conclusion. Crystalluria examination is an essential laboratory test for detecting and following pathological conditions, which may induce renal stone disease or alter kidney function due to urine crystals.
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PMID:[Clinical value of crystalluria study]. 1529 32

Morphoconstitutional analysis of urinary calculi, i.e. morphologic examination combined with Fourier transform infrared spectroscopy (FTIR), is of decisive interest for the diagnosis of rare but severe inherited or acquired stone diseases such as cystine, 2,8-dihydroxyadenine, xanthine, struvite, ammonium urate or drug-containing calculi as well as primary hyperoxalurias. In the absence of early diagnosis and proper management, these diseases may lead to progressive loss of renal function. Among common forms of calcium oxalate (CaOx) stones, predominant CaOx monohydrate (whewellite) is mainly associated with hyperoxaluric conditions whereas predominant CaOx dihydrate (weddellite) is mainly associated with hypercalciuria, and this distinction is of interest to orient metabolic evaluation and preventive measures. Crystalluria examination, also based on morphology and FTIR, is a valuable diagnostic method when no stone is available for analysis. Presence of specific crystals (cystine, 2,8-dihydroxyadenine, struvite, ammonium urate) is diagnostic by itself. In all types of nephrolithiasis, serial crystalluria determination appears as a simple, cheap and reliable method to evaluate the risk of stone formation and assess the effectiveness of preventive measures. Determination of urinary crystal volume was in our experience a useful tool in the management of patients with cystinuria or primary hyperoxaluria in the post-transplantation period. In conclusion, both accurate morphologic and FTIR analysis of stones and serial crystalluria determination should be more largely used, in view of their value in the diagnosis and management of renal stone formers.
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PMID:Clinical value of crystalluria and quantitative morphoconstitutional analysis of urinary calculi. 1549 12

To determine the effects of ammonium chloride (NH4Cl) dosage and swimming exercise training during 4 weeks on bone metabolic turnover in rats, seven-week-old female 24 Wister-Kyoto (WKY) rats were investigated by bone status including bone mineral density (BMD) and biomechanical markers from blood and urine. Twenty-four rats (initial weight: 191.2+/-7.6 g) were randomly divided into four groups: baseline (8 weeks old) control group (n=6, BC), 4-week control group (n=6, Con), 4-week swimming exercise loading group (n=6, Swim) and 4-week chronic NH4Cl dosage group (n=6, Acid). All rats were fed an AIN93M diet (Ca: 0.5%, P: 0.3%), and both Con and Swim groups were pair-fed by feeding volume of the NH4Cl dosage group. The acid group only received 0.25 M NH4Cl distilled water ad libitum. At the end of the experimental period, rats were sacrificed with blood drawn and femur and tibia were removed for analysis of bone mineral density (BMD) by dual energy X-ray absorptiometry (DEXA). In the Swim group, 24-hour urinary deoxypiridinoline (Dpd) excretion, reflecting bone resorption, was significantly increased (p<0.05) with a tendency towards decrease of BMD (N.S.), and body weight and abdominal fat weight were decreased in approximately 7% (p<0.05) and 58% (p<0.001), as compared with age matched Con rats. In the Acid group, 24-hour urinary calcium (Ca) and phosphorus (P) excretion were increased approximately 2.1-fold (p<0.05) and 2.0-fold (p<0.01), respectively, with increase of kidney weight as much as in the Con groups. Serum Ca and P concentration, as well as urinary Dpd excretion were, however, not significantly changed. These results suggest that blood Ca and P concentrations in the chronic acidosis condition during the 4-weeks might be maintained by hypercalciuria and hyperphosphaturia with kidney disorder, and swimming exercise training leads to decrease in BMD with stimulation of bone resorption and reduction of body fat.
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PMID:Effects of chronic NH4Cl dosage and swimming exercise on bone metabolic turnover in rats. 1637 44

Although idiopathic hypercalciuria (IH) is associated with reduced bone mineral density (BMD), no studies to date have identified predictors of BMD change over an extended period of observation. We have studied change in femoral neck and spine BMD z-scores in men and women with IH and stone disease (IHSF) and their first-degree relatives in order to determine the predictive value of commonly made clinical measurements. Urine calcium excretion was inversely correlated with change in femoral neck z-score over 3 years, and marginally correlated with fall in spine z-score. Markers of bone turnover, serum calcitriol, and urine measurements of acid-base balance such as ammonium and sulfate had no predictive value, nor did calcium intake assessed using a well-established questionnaire. It would appear that IHSF with the highest 24-h urine calcium excretion rates are at highest risk for loss of femoral neck bone mineral over a 3-year period.
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PMID:Urine calcium excretion predicts bone loss in idiopathic hypercalciuria. 1694 Oct 29

Published data on the association between calcium oxalate (CaOx) crystallization and kidney stone disease in children are scarce. The aims of this study were to determine CaOx crystallization using the Bonn Risk Index (BRI) in children with urolithiasis in comparison to healthy controls, to evaluate the relationships between BRI and urinary parameters, such as pH, calciuria, oxaluria and citraturia, and to assess the association between BRI and the size of renal stones. We compared the BRI in 142 Caucasian children and adolescents (76 girls, 66 boys) aged 3-18 years with kidney stones and 210 healthy age- and sex-matched controls without urolithiasis. Urinary ionized calcium ([Ca2+]) was measured using a selective electrode, while the onset of spontaneous crystallization was determined using a photometer and titration with 40 mmol/L ammonium oxalate (Ox2-). The calculation of the BRI value was based on the Ca2+:Ox2- ratio. High-resolution renal ultrasonography was carried out to estimate the size of the renal stones. The BRI values were 15-fold higher in children with renal stones than in healthy children without stones. The same trend was shown by BRI/kg body weight (tenfold greater in children with renal stones than in healthy children without stones), BRI/per 1.73 m2 body surface (13-fold greater) and BRI/body mass index (23-fold greater). No association was observed between BRI and the diameter of stones. Children with kidney stones, both males and females, had an increased BRI compared with subjects without urolithiasis. High BRI suggests an association with lower urinary pH, hypercalciuria, hyperoxaluria or hypocitraturia, which are all risk factors of kidney stones. An increased BRI in children, although unrelated to renal stone size, reflects the risk of calcium oxalate crystallization and may indicate early metabolic disorders leading to urolithiasis.
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PMID:A new approach to the diagnosis of children's urolithiasis based on the Bonn Risk Index. 1833 53


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