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

In three groups (n = 12 each) of male controls (22--43 years), patients with recurring calcium urolithiasis (21--36 years) and hyperparathyroidism (HPT; 17--71 years) proven by surgery renal cyclic adenosine monophosphate (RcAMP), fractional tubular phosphate reabsorption and serum parathyroid hormone (PTH) were measured during endogenous creatinine clearance. RcAMP (muMol/g creatinine) was: controls 1.48 +/- SEM 0.27; stone formers 2.037 +/- 0.343 (not significantly different); HPT 6.234 +/- 0.454 (p less than 0.001). There is no overlap between HPT and controls. Phosphate reabsorption is least in HPT (0.84 +/- 0.015), higher in controls (0.924 +/- 0.004) and stone formers (0.941 +/- 0.007). All differences are statistically significant. Under the conditions selected (moderate hydration of individuals) Serum PHT (pg-equiv/ml) is lowest in stome formers (less than 100--339), higher in controls (less than 100--933) and HPT (400--1150). there is no overlap in PHT between the former and the latter group but a marked one between controls and HPT. For clinical purposes the resulting diagnostic uncertainty in a given patient can be overcome by additional determinations of RcAMP and ionised serum calcium: when referring to serum PTH HPT patients fall outside, RCU patients within 2 standard deviations of either parameter in control subjects. This procedure presently appears superior to those proposed in the past (urinary cAMP etc.) but requires confirmation in larger patient populations. Moreover, since HPT prevails in middle and upper age decades, their RcAMP values and those of RCU patients should be related to a range seen in closely age- and sex-matched controls.
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PMID:[Evaluation of renal cyclic adenosine monophosphate, serum parathyroid hormone and phosphate reabsorption in recurrent calcium urolithiasis, healthy controls and hyperparathyroidism (author's transl)]. 21 Mar 11

The incidence of urolithiasis in Manipur is very high. From hospital records for a period of 7 years and 3 months, it was observed to be 11.6% of all general surgery cases in the General Hospital, Imphal. This is alarmingly high. The social, eating, drinking, and living habits are different among the three major populations in this state. The prevalence was minimal among Tribals. Compared to them the prevalence was about one and one half times higher among Muslims (also called Pangals) and seven times higher among Hindus. Surprisingly, the incidence of renal calcalus was higher in females. One hundred ninety-six stones were studied by wet chemical analysis. Calcium and oxalate were present in all stones. Phosphate was present in 194 stones and uric acid (including urate) was present in 146 stones.
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PMID:Urolithiasis in Manipur (north eastern region of India). Incidence and chemical composition of stones. 68 68

Experimental evidence indicates that maintenance of urinary pH < or = 6.4 is the single most effective means of preventing feline struvite crystalluria or urolithiasis of noninfectious causes. This may be accomplished by dietary acidification, but must be moderated to avoid potential adverse effects of excessive acidification, including bone demineralization, negative calcium balance, potassium depletion, and renal disease. Effects of chronic dietary phosphoric acid supplementation on acid-base balance and on mineral and bone metabolism were investigated in adult, domestic cats. One group of 6 cats was fed a basal, naturally acidifying diet without added acidifiers, and another group of 6 cats was fed 1.7% dietary phosphoric acid. Changes observed during 12 months of study included development of noncompensated metabolic acidosis, increased urinary calcium excretion, and lower but positive calcium balance in cats of both groups. Urinary pH decreased in cats of both groups, but was significantly (P < 0.05) and consistently maintained < or = 6.4 in cats given dietary phosphoric acid. Urinary phosphorus excretion increased in cats of both groups, but was significantly (P < 0.05) greater in phosphoric acid-supplemented cats, leading to lower overall phosphorus balance as well. Potassium balance decreased in cats of both groups, but was only transiently negative in the phosphoric acid-supplemented cats midway through the study, and normalized at positive values thereafter. Plasma taurine concentration was not affected by dietary acidification, and remained well within the acceptable reference range for taurine metabolism. Double labeling of bone in vivo with fluorescent markers was followed by bone biopsy and histomorphometric measurement of several static and dynamic variables of bone formation. Overall indices of bone formation decreased in cats of both groups with age and confinement, but were not affected by dietary phosphoric acid supplementation. Dietary supplementation with phosphoric acid used as the principal inorganic P source to achieve moderate and stable degree of urinary acidification, did not appear over the course of 1 year, to have induced adverse effects on mineral, bone, or taurine balance in these adult domestic cats.
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PMID:Effect of dietary phosphoric acid supplementation on acid-base balance and mineral and bone metabolism in adult cats. 146 11

Using an animal model involving rats fed tetraethylorthosilicate, the minimal effective dietary concentration of ammonium chloride for reduction of silica urolithiasis was determined to be approximately 0.10 equivalents/kg diet. Ammonium sulfate appeared to be only slightly less effective. The lower incidences of urolithiasis were associated with urinary pH less than 7. A subprophylactic concentration (0.067 equivalents/kg diet) of ammonium chloride was factored with three levels of supplemental phosphorus (0, 0.15 and 0.30%) from Na2HPO4 to determine whether the antiurolithic effects of dietary phosphate and urinary-acidifying salts are synergistic. Phosphate had no effect on urinary pH. A 50% urolith incidence occurred in controls; the incidence was 25% (P = 0.08) with 0.15 and 10% (P less than 0.01) with 0.30% phosphorus. Urinary pH was 7.5 in controls compared with approximately 7.2 in rats given the subprophylactic level of ammonium chloride, but ammonium chloride alone had no effect on urolithiasis. However, complete protection from urolithiasis was provided by each of the two levels of phosphorus in combination with ammonium chloride. It is concluded that supplemental dietary phosphorus is most effective for protection against silica urolithiasis under conditions contributing toward urinary acidification due to a possible synergism between dietary phosphorus and urinary acidifying salts.
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PMID:A possible synergism of dietary phosphate and urine-acidifying salts in preventing silica urolithiasis in a rat model. 282 Dec 3

Phosphate concentration and pH were studied as factors influencing the formation of insoluble protein-polysilicic acid complexes of bovine serum albumin (BSA) or urinary proteins (nondialyzable urinary solids, NDUS) with silicic acid under conditions of constant ionic strength (IS) equivalent to 0.1724 N. In the pH range 5.5-7.0, the amount of protein-silicic acid complex measured turbidimetrically increased with decreasing pH. Only a trace of precipitate occurred with use of either of the protein sources at pH 7 or with NDUS at pH 6.5. With BSA at pH 6.5, phosphate supplying the total IS of the solution completely prevented precipitation of the complex. The phosphate effect was linear when it supplied 20-50% of the IS. In this range, there was a 12.3% reduction in the amount of precipitate for each 10% of the IS supplied by phosphate. With NDUS at pH 6.0, the phosphate effect was linear over its full range of concentrations. The phosphate effect resulted in an 8.7% reduction in the amount of precipitate for each 10% of the IS supplied by phosphate. On removal of the precipitated protein-silicic acid complex from the silicic acid solution, dissolution was facilitated by increases in phosphate concentration and pH. It is concluded that phosphate inhibition of protein-polysilicic acid complex formation may play a role in the reduction of silica urolithiasis related to increases in dietary phosphate.
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PMID:Phosphate inhibition of protein-polysilicic acid complex formation in vitro: a factor in preventing silica urolithiasis. 282 32

The pathophysiologic consequences of renal function impairment and chronic renal failure among others result from the loss of excretory and regulatory functions of the kidneys. The role of the exchange of cellular hydrogen ions of tubular fluid in the reabsorption of bicarbonate and in the urinary excretion of titratable acid and ammonia (acid-base regulation) is outlined. The effects of decreased glomerular filtration rate on calcium and phosphorus homeostasis are discussed. De novo urolithiasis in these patients is uncommon. However, it is well recognized that they may form matrix stones with calcium oxalate inclusions. Of greater significance is the prophylaxis in those patients, in whom urolithiasis has been the cause of chronic renal failure. In these patients it is of importance to modify the drug dosage or to abandon the prophylaxis when it interferes with the metabolic changes of renal function impairment. Some agents require no modification, others minor or major modifications. Some are even contraindicated. Hazards of stone prophylaxis in chronic renal failure: Acidification - cave metabolic acidosis! Cave RTA! Antibiotic agents - special rules to prevent accumulation. Thiazides - contraindicated! Hypokalemia; hyperuricemia; cave HPT! Triamterene - contraindicated! Acetazolamide (cystinuria) - contraindicated. Spironolactone - contraindicated. Sodium-cellulose-phosphate - Hyperoxaluria, hypomagnesiuria , hyperphosphatemia, cave HPT. Orthophosphate - cave urinary infection, cave poor renal function, cave obstruction. Allopurinol - dose reduction advisable. Brenzbromaron - contraindicated.
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PMID:[Prevention of calculus recurrence in impaired kidney function]. 653 25

Of 205 consecutively analysed urinary stones, two-thirds were from men, which reflected the male: female ratio of urolithiasis cases at this hospital in the period of the study. Phosphate was found in 69.9% of the stones from male patients and in 94.2% of those from female patients. The phosphate in the urinary stones consisted of hydroxylapatite, carboxylapatite and/or MgHN4PO4. CaHPO4 could be demonstrated in only six of the 205 stones. Oxalate was present in 59.6 and 39.1% of the stones from males and females, respectively. Calcium phosphates from saturated solutions precipitated mainly as hydroxylapatite at pH levels above 5.47. Only below this level did CaHPO4 become visible in infrared spectrophotometry analysis. The solubility of calcium phosphates greatly increased with lowering of the pH. Increasing the ionic activity of the saturated solution with sodium chloride increased the solubility of calcium phosphates only to a limited extent.
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PMID:The composition of urinary stones analysed by infrared spectrophotometry and the precipitation of calcium phosphates from saturated solutions. 732 49

A simple, reliable high-performance liquid chromatographic method was developed to measure ascorbic acid (ASC), with ultraviolet detection (250 nm), in human plasma and urine. Immediately following blood withdrawal, the heparinized plasma samples were deproteinized with 10% m-phosphoric acid, while the freshly voided urine samples were diluted with m-phosphoric acid. ASC was separated on a reversed-phase column by elution with 0.1 M KH2PO4 adjusted to pH 2.35. In urine, after reduction of dehydroascorbic acid to ASC, total ASC was measured using the same mobile phase. The method was sensitive down to 0.1 and 0.4 mg ASC per litre of urine and plasma, respectively. In patients with idiopathic calcium urolithiasis, both plasma and urinary ASC were within the range observed in age-matched controls.
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PMID:Measurement of ascorbic acid in human plasma and urine by high-performance liquid chromatography. Results in healthy subjects and patients with idiopathic calcium urolithiasis. 800 35

An ICPMS method for the determination of phytic acid in human urine based on the total phosphorus measurement of purified extracts of phytic acid is described. Pretreatment of the sample is required to avoid interference in the ICPMS detection from other phosphorus compounds accompanying phytic acid in urine such as phosphate or pyrophosphate. This treatment consists of a simple filtration of the urine sample followed by complete separation of phytic acid from the mentioned phosphorus components using an anion-exchange solid-phase extraction. Separation/recovery conditions, optimized for standards of phytic acid prepared in water and artificial urine, were successfully applied to natural urine samples, resulting in adequate accuracy and precision. Linear range (0.02-0.6 mg of phytic acid L(-)(1)) and limit of detection (5 microg L(-)(1) phytic acid) are adequate for analysis of the usual amounts of phytic acid present in urine. Phosphate, pyrophosphate, and pH of urine samples at concentrations exceeding their normal physiological ranges do not affect the determination of phytic acid. Because of the simplicity, low sample requirement, and relatively high sample throughput (10 to 6 min per sample for runs between 50 and 100 samples, respectively), the present method presents the best alternative to current methods for phytic acid determination in urine. Results also show that the method is adequate for the differentiation of levels of phytic acid excretion from patients suffering from oxalocalcic urolithiasis and healthy controls, suggesting that low phytic acid concentrations in urine lead to elevated risk of oxalocalcic urolithiasis.
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PMID:Determination of phytic acid in urine by inductively coupled plasma mass spectrometry. 1461 25

Though the primary role of lasers in urology has always been in the treatment of urolithiasis, there are several other indications for their use. There are many different types of lasers currently available, each with unique properties conducive to treating certain disorders. As such, it is critical that today's urologist understands each laser's characteristics in order to optimize patient selection and treatment. The lasers which are primarily used in urologic applications include the carbon dioxide (CO2) laser; the Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG); the Potassium Titanyl Phosphate (KTP) laser and the Holmium:YAG (Ho:YAG) laser. This review focuses on the unique characteristics of each of these lasers as well as the instrumentation needed utilize and deploy these tools in the urinary tract.
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PMID:Urologic laser types and instrumentation. 1914 May 77


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