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

Urolithiasis, following implantation of Zn discs in urinary bladder (foreign body insertion technique), was examined in albino rats of either sex. Marked variation was observed between sex, regarding the formation of bladder stones. Ethylene glycol (1%) mixed in drinking water for 4 weeks, was unable to augment Zn disc-induced stone deposition. Chemical nature of stones was identified as of magnesium ammonium phosphate type. Neither urinary pH nor infection in the urinary bladder/tract affected chemical nature and quantity of stone formed. There was no significant influence of electrolytes or metabolic products on the uroliths. No correlation could be drawn between the quality and quantity of uroliths formed and the urinary electrolytes concentration. M. Pudica was not effective in either preventing stone deposition or dissolving preformed stones.
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PMID:Biochemical mechanisms and effects of Mimosa pudica (Linn) on experimental urolithiasis in rats. 236 19

In this paper, urolithiasis is remarked from the standpoint of descriptive epidemiology, which examines the frequency distribution of a given disease in a population in terms of time, place and personal characteristics with an aim of identifying risk factors or some clues to the etiology. Some descriptive epidemiological features of urolithiasis are summarized. Prevalence rate is around 4% (4-15% in males and 4-8% in females), and incidence rate varies from area to area: 53.2 per 100,000 population in 1975 in Japan, 364 in 1976 in Malaysia, and 540 in 1979 in West Germany. Prevalence and/or incidence rates have, in general, increased in the developed countries since World War II and in the developing countries as well, where upward trends are quite analogous to the trends observed in the nineteenth century in Europe. Recurrence rate, which is much higher in males than in females, ranges from 31% to 75%, depending on the follow-up periods. In the industrialized countries, upper urinary (renal and ureteral) stones account for more than 90% of total stones, which are ordinarily calcium complexes in composition. More common in the developing countries are lower urinary (bladder and urethral) stones, frequently composed of magnesium ammonium phosphate, which indicates a close association with urinary tract infections. Variations in frequency are evident by season and by region within a country. Age and sex differentials in urinary stone formers are substantial: more common in males 30-40 years old in the industrialized countries and in children under 10 years old in the developing countries. Racial differentials are also noted; blacks appear to suffer less frequently than whites. Stone formers experience more frequent episodes of stone formation in their family members, particularly father and brothers, than non-stone formers. These findings on racial differentials and family preponderance suggest the possible relevance of genetic factors in stone formation. Stone formers are more likely to be occupationally sedentary and socially affluent. This observation and differentials by age and sex suggest the probable relevance of lifestyle and environmental factors in stone formation. Epidemiological factors incriminated for stone formation will be discussed in a separate paper.
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PMID:[Descriptive epidemiology of urolithiasis]. 267 77

In this paper, urolithiasis is reviewed from the standpoint of analytical epidemiology, which examines a statistical association between a given disease and a hypothesized factor with an aim of inferring its causality. Factors incriminated epidemiologically for stone formation include age, sex, occupation, social class (level of affluence), season of the year and climate, dietary and fluid intake and genetic prodisposition. Since some of these factors are interlinked, they are broadly classified into five categories and epidemiologically looked over here. Genetic predisposition is essentially endorsed by the more frequent episodes of stone formation in the family members of stone formers, as compared to non-stone formers. Nevertheless, some environmental factors (likely to be dietary habits) shared by family members are believed to be relatively more important than genetic predisposition. A hot, sunny climate may influence stone formation through inducing dehydration with increased perspiration and increased solute concentration with decreased urine volume, coupled with inadequate liquid intake, and possibly through the greater exposure to ultraviolet radiation which eventually results in an increased vitamin D production, conceivably correlated with seasonal variation in calcium and oxalate excretion to the urine. Urinary tract infections are importantly involved in the formation of magnesium ammonium phosphate stones in particular. The association with regional water hardness is still in controversy. Excessive intake of coffee, tea and alcoholic beverages seemingly increase the risk of renal calculi, though not consistently confirmed. Many dietary elements have been suggested by numerous clinical and experimental investigations, but a few elements are substantiated by analytical epidemiological investigations. An increased ingestion of animal protein and sugar and a decreased ingestion of dietary fiber and green-yellow vegetables are linked with the higher probability of stone formation in the industrialized countries. No trace elements in foodstuffs and liquids have been epidemiologically associated. The dietary guidelines for avoiding stone formation and/or recurrence are summarized in this paper, including other daily-life recommendations.
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PMID:[Analytical epidemiology of urolithiasis]. 267 78

Urinary acidification previously was shown to be an effective treatment for calcium-induced urolithiasis in domestic fowl, but diuresis caused by the acidifying agent (ammonium chloride) was an undesirable side effect. Because supplemental dietary methionine reportedly acidifies mammalian urine, an experiment was conducted to evaluate the efficacy of the free acid form of methionine hydroxy analog (MHA) as an acidifying agent for treating avian urolithiasis. From 5 to 17 wk of age, immature Single Comb White Leghorns were fed diets containing normal calcium (1%) or high calcium (3.5%). Diets were supplemented with 0, 0.3 or 0.6% MHA. Relative to birds fed the normal calcium diets, birds fed the high calcium diet without added MHA were in a state of metabolic alkalosis and excreted more alkaline urine containing high levels of calcium. Birds fed the high calcium diet without MHA also had significantly higher kidney asymmetry ratios, a higher incidence of gross kidney damage, and a higher incidence of urolith formation when compared with birds fed normal calcium diets. When compared with the high calcium diet without MHA, the high calcium diet supplemented with 0.6% MHA significantly acidified the urine without causing detectable metabolic acidosis, significantly reduced kidney asymmetry and gross kidney damage, and reduced the incidence of urolith formation without increasing water consumption or urine flow. These data demonstrate that MHA effectively prevents calcium-induced kidney damage in domestic fowl without causing undesirable side effects. MHA did increase both fractional and absolute calcium excretion during calcium loading.
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PMID:Methionine hydroxy analog (free acid) reduces avian kidney damage and urolithiasis induced by excess dietary calcium. 272 31

A total of 191 children with oxalate-phosphate urinary concrements and 28 virtually healthy ones were studied for the main parameters of acid-base blood status with the use of Astrup's microtest. Besides, the urine circadian levels of acid and ammonium were followed up too. The proportion of the main and H+-secreting insertion cells of collecting tubes were calculated in 46 operative biopsy specimens, cells studied with electron microscopy. Advanced metabolic acidosis associated with a decrease in acid and ammonium titration was diagnosed in all patients with bilateral and in 81.6 per cent with unilateral nephrolithiasis. Regardless of acid-base blood status biopsy examination revealed a decrease in the number of insertion cells in renal collecting tubes of the patients mostly pronounced in those with bilateral concrement localization. Ultrastructure of insertion cells in children with oxalate-phosphate urolithiasis featured by a sharp decrease in mitochondria number, absence of smooth-walled vesicles, frequency of myelinoid lysosomes pointed to the failed competence of these cells to efficient H+ secretion. The data obtained evidence of the relationship between the metabolic acidosis and primary disability of the children's kidney to excrete H+.
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PMID:[Acid-base balance of the blood and possible renal mechanisms of its imbalance in children with oxalate-phosphate stones of the urinary tract]. 277 79

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

The etiopathogenesis of uric acid, sodium acid urate, and ammonium acid urate uroliths in non-Dalmatian dogs appears to be a complex phenomenon. It may involve one or more pathologic and/or physiologic processes acting independently or in concert to increase urinary concentration of lithogenic substances that result in initiation, growth, and retention of urate uroliths. Increased urine uric acid concentration and/or urinary excretion of uric acid appear to be primary predisposing factors in urate lithogenesis. Specific disorders resulting in hyperuricuria may involve abnormalities of increased synthesis, diminished biodegradation, and/or enhance excretion of uric acid. In addition, ammonium ion, hydrogen ion, and other organic and inorganic urine constituents appear to have major influences on urate urolith formation. Unfortunately, many specific disorders of uric acid metabolism and other factors promoting or inhibiting urate urolith formation remain poorly characterized in the majority of non-Dalmatian dogs with urate urolithiasis. Growing awareness of the significance of urate uroliths in non-Dalmatian dogs should encourage further investigation into the identification, characterization, and quantitation of parameters influencing urate lithogenesis. Results of such studies are required for development of practical and effective strategies for treatment and prevention of canine urate urolithiasis.
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PMID:Etiopathogenesis of uric acid and ammonium urate uroliths in non-Dalmatian dogs. 351 3

The increasing incidence of urolithiasis makes it important to report about 34 children with urolithiasis seen between 1976 and 1986 at the Department of Pediatrics, University Medical School Vienna. At the time of the first diagnosis 59 percent of the patients were less than 7 years of age; 62 percent of our patients were males. Recurrent chronic urinary tract infection in 32 percent, metabolic disorder (secondary hyperoxaluria 5, idiopathic hypercalciuria 3, cystinuria 2, hyperuricuria 2) in 27 percent were evaluated; in 13 patients the origin of calculi was idiopathic. Most infectious stones contained magnesium ammonium phosphate, most idiopathic stones calcium oxalate. In 21 patients (62%) surgical treatment, in one patient extracorporal shock wave lithotripsie was realized. Adequate metaphylaxis (general, dietetic, medicementous) can lower the rate of occurrence of stone formation.
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PMID:[Urolithiasis in pediatrics: analysis of 34 patients]. 368 52

Fifty-two cases of urinary tract calculus disease were investigated for dietary habits, routine chemical and microscopic urinalysis, bacterial culture, quantitative analysis of 24 h urine sample and qualitative analysis of the stones. 54 out of the 56 stones analysed were of mixed type. Magnesium ammonium phosphate was present in 78.2% stones. Dietary habits revealed principal dependence on cereals, lack of animal proteins, consumption of oxalate rich vegetables and widespread consumption of tea. Urinary tract infection was present in 63.7% of the cases. Significant calcium oxalate crystalluria (2+ to 4+) was present in 34.6% of the cases. Hyperoxaluria, hypercalciuria associated with hyperoxaluria-lower excretion of magnesium and citric acid were important urinary risk factors in the local population. These observations strongly suggest the multifactorial etiology of stone disease in this region. Imbalanced nutrition and urinary tract infection were the principal risk factors for urolithiasis in this study.
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PMID:The etiology of urolithiasis in Udaipur (western part of India). 372 15

Urolithiasis (kidney stone formation) is an acquired degenerative kidney lesion affecting sexually mature and immature domestic fowl. For the present study, uroliths were collected from three commercial flocks during outbreaks of urolithiasis. Uroliths also were collected from a research flock in which urolithiasis was induced by feeding immature chickens a diet formulated to contain excess calcium (3.25% Ca) and .4% available phosphorus. All uroliths were tested by x-ray diffractometry, infrared spectrophotometry, and emission spectrography. With one exception, the stones were composed of compact masses of microcrystalline to fine pleomorphic crystals of calcium sodium urate, with random substitution of magnesium for calcium, and potassium for sodium. No initiating nidus was evident. One of four stones from one laying hen flock was positively identified as an ammonium acid (hydrogen) urate. The unique calcium-sodium-urate stone composition in all but one of the stones tested suggests that similar processes were involved in stone formation in the four different flocks.
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PMID:Characterization and composition of uroliths from domestic fowl. 373 19


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