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Query: UMLS:C0451641 (urolithiasis)
 3,973 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study of ammonium and sodium urate precipitation in vitro and the fine structure of several urate renal calculi was carried out to contribute to an understanding of the participation of ammonium and sodium urates in urolithiasis. Ammonium urate precipitated in vitro in two different morphologies: a typical spherulite morphology formed at high supersaturation and disorganized needle-like crystals formed at low supersaturation. In all cases sodium urate precipitated in vitro as bundles of curved fibrils, its crystallization being inhibited by calcium in concentrations between 20 and 60 mg/l depending on the sodium urate supersaturation. From a collection of 1300 renal calculi, only three had ammonium urate as their main component (0.2%), three were mixed calculi (0.2%) consisting of ammonium urate and calcium oxalate (two) or uric acid (one), and in one calculus ammonium urate was present as a minor component. Only in a mixed calculus of uric acid and calcium oxalate was sodium urate detected in a very low quantity. The study of the fine structure of the renal calculi constituted mainly by ammonium urate demonstrated similar patterns in which spherulites, needle-like individual crystals and an amorphous mass of ammonium urate with abundant organic matter in non-organized structures coexist. As minor components, struvite or calcium oxalate crystals were found. A general mechanism of the formation of such calculi is proposed.
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PMID:Ammonium and sodium urates precipitating from synthetic urine and fine structure of urate renal calculi. 1042 96

Cystine urolithiasis is the only clinical expression of cystinuria, an autosomal recessive genetic defect of the transepithelial transport of cystine and other dibasic amino acids in the kidney. Stones form due to the increased excretion of cystine, which is poorly soluble at normal urine pH. Cystine stones are often resistant to extracorporeal shock wave lithotripsy, so that percutaneous surgery or ureteroscopy are the preferred techniques of stone extraction. Medical preventative treatment is based on high diuresis (>/=1.5 l/m(2) per day) well distributed throughout the day and night, and urine alkalinization up to pH 7.5 by means of sodium bicarbonate and/or potassium citrate. When these basal measures are ineffective at preventing stone recurrence or dissolving pre-existing stones, sulfhydryl agents such as D-penicillamine or tiopronin, which form highly soluble mixed disulfides with cystine moieties, are to be added to urine dilution and alkalinization, especially when cystine excretion is in excess of 750 mg/day (3 mmol/day). Frequent clinical and ultrasound follow-up is needed to encourage patient compliance and assess efficacy and tolerance of treatment.
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PMID:Treatment of cystinuria. 1104 3

Apart from a minority with urolithiasis, the majority of children diagnosed with idiopathic hypercalciuria present with macro- or microhematuria, abdominal or back pain, or voiding symptoms. With dietary and pharmacological interventions, most such children become asymptomatic and are lost to follow-up, hence their long-term outcome is unclear. In the present study, we evaluated the status of 14 males and 19 females aged 8-17 years (mean 11.9 years, median 11.2 years) 4-11 years (mean 6.9 years, median 6.5 years) after the initial diagnosis of idiopathic hypercalciuria not associated with urolithiasis. A questionnaire was answered and two random urine samples provided 3-4 weeks apart were analyzed for calcium (Ca), sodium (Na), potassium (K), and creatinine (Cr). Urine Ca/Cr ratio > or =20.21 (mg/mg) was defined as hypercalciuria. At the time of the study none were under follow-up, although 7 children were still exhibiting voiding symptoms. No child developed clinical urolithiasis. Based on the first urine specimen, 16 of the 33 (48.4%) were hypercalciuric. Their 2nd urinalysis showed persistent hypercalciuria in 8 and normocalciuria in 8. Urine Na/K ratio (mEq/mEq) decreased in the latter 8 from 5.08+/-2.67 to 3.03+/-2.23 (P<0.05). Of the 17 initially normocalciuric children, 5 did not submit a 2nd specimen, 11 remained normocalciuric, and 1 became hypercalciuric with an increase in urine Na/K ratio. Twenty-three children (all 8 persistently and 9 intermittently hypercalciuric plus 6 normocalciuric) were studied by ultrasonography. Only in 1 asymptomatic persistently hypercalciuric child was a single small renal calcification noted. Introduction of a low-Na/high-K diet in 7 persistently hypercalciuric children resulted in a decrease in UNa/K ratio from 7.34+/-2.15 to 4.14+/-3.09 (P<0.01) and UCa/Cr ratio from 0.25+/-0.04 to 0.13+/-0.03 (P<0.01). We conclude that even though over time most hypercalciuric children become asymptomatic, many remain hypercalciuric. Further follow-up is required to ascertain whether these children are at risk of developing kidney stones. If they are at risk then long-term compliance with a low-Na/high-K diet might be beneficial, as it can normalize calciuria in the majority of these children.
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PMID:Idiopathic hypercalciuria of childhood: 4- to 11-year outcome. 1097 18

The factors precipitating clinically active calcium oxalate (CaOx) urolithiasis are not known. This study examined the relationships between urinary proteins that inhibit CaOx crystallization in vitro and the incidence of CaOx urolithiasis. The first hypothesis is that levels of urinary CaOx crystallization inhibitors differ between clinically active stone formers (SFs) and normal individuals. The second hypothesis is that lower levels of urinary CaOx crystallization inhibitors contribute to the two- to threefold greater incidence of CaOx urolithiasis in males compared with females. These hypotheses were derived from previous observations on the expression of urinary inter-alpha-trypsin inhibitor trimer (IalphaTI-trimer) in normal and stone-forming individuals. The proteins of void urine samples from normal volunteers (24 males, 19 females) and CaOx-SFs (26 males, 16 females) were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoreactive IalphaTI-trimer, osteopontin, and prothrombin were detected by immunoblot plus enhanced chemiluminescence; the relative densities of the bands were then determined. With the exception of IalphaTI-trimer (P: </= 0.026, approximately twofold), there was no difference in the relative densities of CaOx crystallization inhibitors in the urine of normal and CaOx stone-forming individuals. Thus, there does not appear to be a generalized increase or decrease in levels of CaOx crystallization inhibitory proteins between normal and CaOx stone-forming individuals. The relative density of IalphaTI-trimer was approximately threefold greater in females than in males (P: </= 0.001). Differences in the relative densities of the other CaOx crystallization inhibitors were small and of questionable physiological importance. These data do not support the hypothesis that males have a greater incidence of CaOx urolithiasis because of a generalized decrease in urinary CaOx crystallization inhibitory protein levels.
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PMID:Expression of proteins that inhibit calcium oxalate crystallization in vitro in the urine of normal and stone-forming individuals. 1113 74

Biochemical tests by 12 metabolic blood and urine indices reflecting the condition of renal function and metabolism of urolithogenic substances were made in the course of 1-6 year follow-up of 35 and 79 patients (46 females and 68 males aged 18-65 years) with recurrence-free and recurrent urolithiasis, respectively. The risk of recurrence for uric acid urolithiasis in serum concentration of urea 5.67 +/- 0.14 mmol/l and creatinine 0.090 +/- 0.008 mmol/l, in hyperuricemia and hyperuricuria was associated with elevation of renal excretion of total calcium to 5.88 +/- 0.49 mmol/day and ratio of daily renal excretion of sodium to renal daily excretion of potassium to 3.28 +/- 0.08; for calcium-oxalate lithiasis--with a rise in serum concentration of uric acid to 0.310 +/- 0.042 mmol/l and sodium to 114 +/- 0.8 mmol/l in hypercalciuria and hyperuricuria.
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PMID:[Recurrence-free and recurrent urolithiasis: metabolic differences]. 1115 Jan 60

Acute renal insufficiency (ARI) complicated the course of the underlying process, including primary and secondary glomerulonephritis, interstitial nephritis, pyelonephritis, dysmetabolic nephropathies, urolithiasis, tubulopathies, renal congenitae defects and injuries in 136 of 1695 children with nephrological diseases hospitalized at Republican Pediatric Renal Center during the last decade. In 69.1% cases ARI developed by the renal type, in 23.5% cases was caused by prerenal factors, and rarely (in 7.4% cases) by postrenal factors. Renal ARI in children was caused by 5 causes, including glomerulonephritis (47%), acute tubular necrosis (19%), interstitial nephritis (14%), vascular disorders (11%) resultant from vasculitis, renal vein thrombosis, and acute crystalluria (9%) which developed in the presence of grave dysmetabolic nephropathy. Among three clinical variants of ARI the most severe was observed in renal ARI leading to grave endogenous intoxication and pronounced decompensation of renal function. More benign course of renal ARI caused by acute tubular necrosis or acute crystalluria differed significantly from prerenal ARI by a more pronounced endogenous intoxication, increased fractionated sodium excretion, and renal insufficiency index higher than 1.
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PMID:[Diagnosis of acute renal failure in pediatric nephrology]. 1133 30

In 1998, two cases of silica urolithiasis occurred in castrated male dromedaries on an intensive camel farm in the Canary Islands. The immediate attributable cause was the ingestion of large amounts of silica in the feed, estimated as 84.44 g/day. An associated cause was the low level of salt in the diet. Daily ingestion of salt from feed and water was estimated to be 21.8 g (8.6 g of sodium). Seventy-six castrated males from the same farm were divided into four groups: group A received 30 g of salt daily; group B received 40 g; group C received 60 g; and group D received no added salt in the diet (control). The animals were maintained on these dietary regimes for 2 years. No animals from groups A, B or C suffered overt urinary retention. One animal from group D had an obstructive urinary retention 10 months after the study commenced. Thus, 52 g of salt daily appears to be sufficient to prevent urinary retention in dromedaries raised in a subtropical climate.
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PMID:Silica urolithiasis in the dromedary camel in a subtropical climate. 1224 Oct 96

Phyllanthus niruri is a plant used in Brazilian folk medicine for the treatment of urolithiasis. It was previously observed that P. niruri shows no toxicity, potentially increases calculus voiding by stone forming patients and inhibits the endocytosis of calcium oxalate (CaOx) crystals by MDCK cells. In addition, in a rat model of urolithiasis it reduced calculus growth. In the present study, we evaluated the effect of an aqueous extract of P. niruri on CaOx crystallization in vitro. CaOx precipitation was induced by the addition of 0.1 M sodium oxalate to unfiltered urine samples from Wistar rats (n=14) and normal humans (n=18) in the presence or absence of P. niruri extract (0.25 mg/ml of urine). The presence of CaOx crystals was evaluated immediately and 24 h later. In vitro crystallization of human urine produced typical mono- and dihydrated CaOx crystals, but only a few typical CaOx crystals were found in rat urine. The presence of P. niruri extract did not inhibit CaOx precipitation and even more crystals were obtained, although they were significantly smaller than those in the control urine. Crystal aggregation observed 24 h after crystallization was also inhibited by P. niruri extract. The results showed an inhibitory effect of P. niruri extract on CaOx crystal growth and aggregation in human urine, suggesting that it may interfere with the early stages of stone formation and may represent an alternative form of treatment and/or prevention of urolithiasis
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PMID:Effects of an aqueous extract from Phyllantus niruri on calcium oxalate crystallization in vitro. 1259 17

We report a case of urolithiasis associated with short bowel syndrome. A 56-year-old woman was admitted to our hospital for asymptomatic bilateral renal stones. She had received extensive resection of small intestine due to strangulating obstructive ileus 7 years ago (residual intestine, only 20 cm). Subsequently, she was in a state of short bowel syndrome. Plain film of kidney, uteter, bladder and computed tomography revealed bilateral renal stones (right 4 mm, left 10 mm). The left renal stone was successfully treated by extracorporeal shock wave lithotripsy. Since the right renal stone was small, no treatment was performed. The stone fragments were composed of calcium oxalate and calcium phosphate, and excessive urinary excretion of oxalate (103.8 mg/day) was observed. In this patient, urolithiasis was diagnosed to be due to enteric hyperoxaluria caused by short bowel syndrome. To prevent the recurrence of stone formation, she was treated with oral administration of calcium lactate, sodium/potassium citrate and magnesium oxide. We review the Japanese literatures on urolithiasis with short bowel syndrome.
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PMID:[A case of urolithiasis associated with short bowel syndrome]. 1263 4

This paper deals of kidney stones, hard concretions that grow within the urinary tract, 71.5% of which have calcium contents. A high rate of recurrences underscores the importance of medical prevention with a variety of conservative (increased fluid intake and dietary modifications) and drug therapy (potassium citrate, potassium magnesium citrate, thiazides, allopurinol). In single stone formers and mild recurrent diseases, the conservative therapy may alone be effective and should be maintained in more severe recurrent disease, together with drug treatment. In particular, in idiopathic calcium oxalate nephrolithiasis, the importance of sodium restriction in the diet, that should reduce calcium excretion, has been recently shown, limiting the old assumption of the value of dietary calcium restriction; in fact normal or higher calcium intake, binding oxalate in the intestinal tract, seems to confer protection against stone formation. The urologic approach to urolithiasis has changed with the introduction of extracorporeal shock wave lithotripsy (ESWL), a technique that allows a relatively noninvasive removal of stones. Nevertheless ESWL does not change the propensity of recurrence of stone formers, and the importance of medical prevention remains paramount in the management of renal stone disease.
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PMID:[Etiopathogenesis and clinical aspects of nephrolithiasis--at present]. 1267 82


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