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

Because human urine contains various substances which can affect each other, it is quite difficult to clarify the mechanism of formation of calcium oxalate (CaOx) crystal in urine. The authors recently determined CaOx crystalline content and the concentrations of other substances in urine specimens from patients with urolithiasis and healthy volunteers, and subjected the data to multi-regressive analysis for the purpose of assessing the effect of these urinary substances on CaOx crystal formation. 1. In analysis of urine from patients with urolithiasis, the partial correlation coefficients of CaOx crystal formation with oxalic acid, sodium, calcium, uric acid magnesium were 0.67, 0.28, 0.18, and -0.10, respectively. The formula of regression was as follows: Amount of CaOx crystal (X 10(6) microns3/ml) = 3.59 X 10(-2) Ox (mM/L) + 4.72 X 10(-3) Ca (mM/L) + 4.52 X 10(-3) Na (mM/L) + 2.51 X 10(-4) UA (mM/L) -2.39 X 10(-2) Mg (mM/L) -1.65. The multiple correlation coefficient was 0.759. Thus, in patients with urolithiasis, urinary crystal formation was most dependent on the oxalic acid level, sodium, calcium, and uric acid were found to promote crystal formation, while magnesium to suppress it. 2. In analysis of urine from healthy volunteers, the partial correlation coefficients of CaOx crystal formation with oxalic acid and inorganic phosphorus were 0.51 and -0.24, respectively. The formula of regression was as follows: Amount of CaOx crystal (X 10(6) microns3/ml) = 1.91 X 10(-2) Ox (mM/L) -3.43 X 10(-4) P (mM/L) +0.29 The multiple correlation coefficient was 0.525.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Studies on calcium oxalate crystal formation in urolithiasis. Multi-regressive analysis of urinary CaOx crystalline volumes and the effects of urinary various substances on CaOx crystal formation]. 187 73

Thirteen urolithiasis patients with unilateral obstructive uropathy were treated with percutaneous nephrostomy (PCN) either for urinary diversion, endopyelotomy, nephrolithtotmy or chemolysis. After percutaneous nephrostomy, the individual urine volume, creatinine clearance (Ccr), urinary absolute and fractional excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were measured separately in timed urine collections from a pigtail catheter and from the urethra. The data showed that Ccr and the absolute urinary excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were significantly lower in the PCN kidney immediately or 2 days after relief of obstruction. The ratio of total urinary calcium excretion to urinary creatinine excretion in the obstructed kidney was significantly greater than that in the contralateral kidney. The fractional excretions of calcium and magnesium increased as renal function decreased. The results showed that when the total Ccr is below normal, the apparent excretion of urinary calcium will be underestimated. However, when the total Ccr of patients is within normal range, hypercalciuria may be detected adequately and thus favors early implementation of an appropriate therapeutic strategy.
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PMID:Reduction of calcium excretion in the stone-forming kidney in unilateral ureteral obstruction. 188 28

In 26 healthy individuals and 114 patients with urolithiasis, total urine protein levels were measured in a single sample by using the stain ponceau S. The findings were statistically analyzed. The levels of the protein were found to be 27-80 mg/l in the healthy individuals, while the distribution of the data was asymmetric as viewed from high values. The patients with urolithiasis exhibited their protein levels according to the type of nephrolithiasis. Proteinuria was demonstrated to be less pronounced in patients with oxalate and urate nephrolithiasis than in patients with coral phosphate calculi. There was a substantial asymmetry in the distribution of total urine protein for all the examined groups of urolithiasis patients, as well as great dispersion values, which fails to regard the parameter alone as a diagnostic criterion for the type of nephrolithiasis. At the same time it was noted that simultaneous examination of the levels of total protein, uric acid, potassium, and sodium enabled the type of a concrement (oxalate or phosphate) to be in vivo estimated with approximately 85% probability.
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PMID:[Total urinary protein in different types of nephrolithiasis]. 194 15

Nephrolithiasis and endemic renal distal tubular acidosis are common in northeastern Thailand. The etiology is still unknown. It is generally accepted that urine electrolytes influence the capacity of urine to inhibit or promote renal and also bladder stones. The purpose of this study was to analyse the composition of the urine in the indigenous population in the northeast area and compare their values with data obtained from a group of age matched adults, living in Bangkok. Twenty-four hour urine samples from 23 normal adult villagers from six villages within the province of Khon Kaen and 34 normal adults living in Bangkok were collected, and the daily excretion of creatinine, uric acid, calcium and inorganic phosphate, sodium, potassium, chloride, magnesium and oxalate were assayed. Daily urinary sodium, potassium, chloride and phosphate of the villagers were significantly lower than those of Bangkokians. No difference in the urinary excretion of calcium, magnesium, uric acid, oxalate and creatinine was found. The Na/Ca, and Ca/PO4 ratios of villagers were significantly lower than those of the Bangkok subjects. The villagers excreted significantly lower amounts of Na in the face of relatively higher urinary Ca. The above data, combined with our previous study showing the low values of urinary citrate in the villagers in the same areas, strongly indicate that the indigeneous population is at high risk in developing urolithiasis. The causes for these electrolyte abnormalities are still unknown. Low contents of the major electrolytes in their diets might play an important role. Low phosphate output indicates low protein diets.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Urinary constituents in an endemic area of stones and renal tubular acidosis in northeastern Thailand. 207 84

Cystinuria is an hereditary disorder of renal and intestinal transport characterized by the excessive urinary excretion of cystine, arginine, lysine, and ornithine. It is inherited as a common recessive gene with allelic mutations. Complementary studies of the plasma response to oral cystine loading, intestinal mucosal transport patterns, and urine cystine excretion allow separation of homozygous cystinuric subjects into three groups. In type I, the most common form, there is no active transport of cystine or dibasic amino acids across the mucosal gradient, and heterozygous subjects show normal urine cystine values. Type II is characterized by markedly reduced or absent intestinal transport of cystine. Heterozygotes for type II show significantly elevated urine cystine but less than is seen in homozygotes. In type III there is diminished, although demonstrable, intestinal absorption of cystine and dibasic amino acids. Urine cystine in heterozygotes is intermediate between types I and II. Urolithiasis with its attendant complications is the sole clinical manifestation of cystinuria and is due to the relative insolubility of cystine in the urine. The urolithiasis may become clinically manifest at any time from infancy through the ninth decade, although the mean age is the second to third decade. Clinical presentation is similar to that of other types of urolithiasis. Although cystinuria accounts for only 1% to 2% of all urolithiasis and 6% to 8% of urolithiasis in pediatric populations, repeated stone formation in affected patients often causes considerable morbidity. Cystine crystals in the urine are diagnostic but show up in only 19% to 26% of homozygous cystinuric patients. Sodium cyanide nitroprusside is a suitable screening test that should identify homozygous stone formers but will not detect all heterozygotes. A positive screening test should be followed by quantitation of urinary amino acids. A homozygous patient can be functionally defined as one who excretes 250 mg or more of cystine/g of creatinine in a 24-hour urine collection. Other causes of excess urinary cystine must be excluded. Medical therapy will be directed toward dissolution of existing calculi and prevention of new stone formation. Increasing urine volume by generous oral fluid intake is beneficial. Dietary sodium restriction has a favorable effect on urinary cystine excretion. Cystine solubility can be improved by urinary alkalinization and where necessary by the administration of thiol chelators, particularly D-penicillamine or mercaptopropionylglycine. Because these chelators have significant adverse effects, they should be reserved for patients who do not respond to a more conservative program. Patients with infected, symptomatic, or obstructing stones require surgical intervention.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cystinuria. 208 17

Sheep were used to study factors previously found to promote silica urolithiasis in a rat model. In addition to high silica, these dietary factors included elevated calcium, a high calcium to phosphorus ratio and alkali-forming effects. Wether lambs had ad libitum access to a diet of 50% of grass hay and 50% ground oats plus supplement. Diet analysis was 3.4% total SiO2, .29% calcium, .25% phosphorus, 11.3% CP and 28% ADF. Treatments (40 lambs/treatment) consisted of a control (C), limestone to increase dietary calcium to .6% (L), L + 1% sodium bicarbonate (LS) and L + 1% ammonium chloride (LA). After a 91-d experimental period followed by a 56-d postexperimental finishing period, silica kidney deposits were found in all treatments, and SiO2 made up 74% to 97% of the urolithic ash. Kidney urolith incidences in the four treatments were C, 7/40; L, 12/40; LS, 20/40; and LA, 9/40. A higher urolith incidence in LS (LS vs C, P less than .05) and a trend toward a higher incidence in L (L vs C, P less than .2), accompanied by elevated urine pH (L = LS greater than C greater than LA, P less than .01), lend support to the concept that high-silica diets having high calcium to phosphorus ratios and alkali-forming potentials contribute to silica urolithiasis.
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PMID:High dietary calcium to phosphorus ratio and alkali-forming potential as factors promoting silica urolithiasis in sheep. 215 99

The most important measure in the prophylaxis of idiopathic calcium urolithiasis is dietary advice. Patients should be kept to a high-fluid intake, increasing their diuresis by at least 0.51. The mineral content of drinking water seems to be of minor importance, but the liquid should be low in carbohydrates and oxalate. The intake of animal proteins should be reduced to no more than five meals with meat, fish or poultry per week. Excesses of oxalate-rich food must be avoided. The daily intake of calcium in dairy products should be in the range of 800-1200 mg. Sodium and refined carbohydrates should be moderately restricted. Medical treatment is indicated only in cases of recurrence under the appropriate diet. Selective treatment according to urinary chemical composition is favoured; alkali citrate, thiazides, allopurinol, and pyridoxine are of major interest.
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PMID:Prophylaxis in idiopathic calcium urolithiasis. 229 Dec 48

We assessed 5 patients with recurrent cystine urolithiasis before and after implementation of a low sodium diet. This diet led to a significant decrease in the 24-hour urinary excretion of sodium and cystine. Dietary restriction of sodium should be an important component of the therapeutic strategy of patients with cystinuria.
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PMID:Dietary restriction of sodium as a means of reducing urinary cystine. 234 81

Dietary excesses in animal protein and/or salt have been implicated as risk factors in calcium oxalate urolithiasis. The underlying physicochemical mechanism is, however, not known. Eight healthy men were given four different diets varying in animal protein and in sodium content for 1 week each. On a high protein intake (2 g/kg.day) significant changes in urinary calcium, uric acid, and citrate excretion rates were found. Similar changes in calcium and citrate were induced by a high sodium intake (310 mmol/day). The changes were more pronounced when a high protein was combined with a high sodium diet. Urinary calcium increased from 3.79 +/- 0.31 to 6.42 +/- 0.61 mmol/24 h and urinary uric acid from 4.69 +/- 0.26 to 8.0 +/- 0.47, whereas urinary citrate decreased from 3.93 +/- 0.53 to 2.79 +/- 0.34 mmol/24 h. All three dietary regimens induced a significant decrease in the ability of urines to inhibit calcium oxalate monohydrate crystal agglomeration, which was most marked during the combined diet (from 345 +/- 39 to 205 +/- 28 min). The ability of urines to inhibit crystal agglomeration was related to their citrate content (r = 0.69, P less than 0.0001). These results show that high animal protein and/or sodium intake decrease the ability of urines to inhibit the agglomeration of calcium oxalate crystals and provide a possible physicochemical explanation for the adverse effects of dietary aberrations on renal stone formation.
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PMID:The effects of dietary excesses in animal protein and in sodium on the composition and the crystallization kinetics of calcium oxalate monohydrate in urines of healthy men. 240 15

Urinary uric acid excretion was assessed in 38 children to determine whether hyperuricuria was a risk factor in children with urolithiasis. Uric acid excretion (measured per deciliter glomerular filtration rate), and fractional excretion of uric acid were similar in 27 children with hypercalciuria and calcium oxalate urinary stones, in six children with idiopathic calcium oxalate urolithiasis, and in five with uric acid urolithiasis, of whom four were white boys and one was an Asian girl. One boy with a urate stone had cystinosis. Serum uric acid concentrations exceeded 6.0 mg/dl (360 mumol/L) in two children with hypercalciuria and in two patients with idiopathic calcium oxalate urolithiasis. None of the children with calcium urolithiasis had excessive urinary excretion of uric acid. In children with hypercalciuria, uric acid excretion did not change significantly when dietary sodium was increased from 1.0 to 5.0 gm/1.73 m2. We conclude that excessive urinary uric acid excretion is seldom an additional risk factor in children with calcium urolithiasis and that dietary sodium chloride does not have a strong influence on urinary excretion of uric acid in children with hypercalciuria.
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PMID:Uric acid excretion in children with urolithiasis. 258 28


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