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

It has been hypothesized that urinary urokinase and sialidase may play a role in urolithiasis. If these theories have substance it is to be expected that microorganisms may also affect these enzymes, since the association between urinary tract infection and renal stone formation is well known. It is generally assumed that Proteus mirabilis and Staphylococcus albus, which produce the urea-splitting enzyme urease, are responsible for stone formation. However, the importance of non-urease-producing microorganisms (Escherichia coli and Enterococcus) in urolithiasis is unclear. Spectrophotometric studies were therefore devised to clarify this problem. Microorganisms associated with infection-induced stones (Proteus mirabilis and Escherichia coli) respectively inhibited the urokinase and stimulated the sialidase activity. In contrast, microorganisms which were not associated with infection stones (Bacillus subtilis) had significantly less effect on urokinase and sialidase activity. This study may explain infection-induced stone formation and could open a completely new line of research.
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PMID:Effects of bacteria involved with the pathogenesis of infection-induced urolithiasis on the urokinase and sialidase (neuraminidase) activity. 146 76

The composition of 3,084 urinary calculi was determined using an infrared spectrophotometer. Mixed calcium oxalate-calcium phosphate stones were most frequently implicated. Of the urinary calculi analyzed 199 were associated with urinary tract infection. Escherichia coli was most frequently isolated (43 strains) and urease-producing organisms, such as Proteus mirabilis, were cultured from 40 patients. The core culture of 20 staghorn calculi yielded 15 isolates from 14 stones. There were 13 identical species isolated from the urine and stone specimens of 13 patients (65%), including 7 strains of P. mirabilis. These results suggest that cultures of urine specimens of urolithiasis patients, especially those with staghorn calculi, may help to elucidate the bacteriology of the stones.
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PMID:Composition of urinary calculi related to urinary tract infection. 150 58

We evaluated the effect of a novel potent urease inhibitor, N-(diaminophosphinyl)isopentenoylamide (IPA), on the development of an infection bladder stone using our urolithiasis model in rats. IPA was excreted into urine after oral administration to rats, and the cumulative urinary recovery rate of unchanged IPA reached about 29.6% within 24 h (50 mg/kg). The oral administration of IPA (6.25 mg/kg, b.i.d., 5 d) significantly inhibited the development of the infection bladder stone. The present result suggests that IPA is a very promising compound in the prevention of formation and recurrence of an infection stone owing to a high efficacy and a low toxicity of IPA in animals.
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PMID:Effects of a novel urease inhibitor, N-(diaminophosphinyl)isopentenoylamide on the infection stone in rats. 189 95

Struvite urolithiasis forms as a consequence of a urinary tract infection by urease-producing species of bacteria such as Proteus mirabilis. Ammonia, produced by the enzymatic hydrolysis of urea, elevates urine pH causing a supersaturation and precipitation of Mg++ as struvite (NH4MgPO4). Calcium often precipitates as well, forming the mineral carbonate-apatite (Ca10(PO4)6CO3). We have developed a procedure based on direct observation by light microscopy whereby struvite crystal growth can be quickly monitored in response to chemical changes in urine. As struvite crystals assume a characteristic shape or crystal habit based on their growth rate, the effect of urine chemistry and the action of various crystallization or urease inhibitors on struvite formation can be quickly shown. In addition preliminary effects of alkaline pH, or the presence of toxic compounds on bacteria can also be shown through their loss of motility.
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PMID:A simple technique for studying struvite crystal growth in vitro. 218 Jan 68

The efficacy of a diet designed to facilitate dissolution of feline magnesium ammonium phosphate (struvite) uroliths was evaluated in 30 cases of urolithiasis, sterile struvite uroliths dissolved in a mean of 36 days after initiation of dietary treatment. In 5 cases of urolithiasis, struvite urocystoliths associated with urease-negative bacterial urinary tract infection dissolved in a mean of 23 days after initiation of dietary and antimicrobial treatment. In 3 cases of urolithiasis, struvite urocystoliths associated with urease-positive staphylococcal urinary tract infection dissolved in a mean of 79 days after initiation of dietary and antimicrobial treatment. Dissolution of uroliths in cats fed the treatment diet was associated with concomitant remission of dysuria, hematuria, and pyuria, and reduction in urine pH and struvite crystalluria. In one case, a urocystolith composed of 100% ammonium urate, and in another case, a urolith composed of 60% calcium phosphate, 20% calcium oxalate, and 20% magnesium ammonium phosphate did not dissolve.
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PMID:Medical dissolution of feline struvite urocystoliths. 232 73

Acetohydroxam acid (500-1000 mg/d) inhibit the activity of the bacterial urease successfully due to reduction of ammonia excretion and urinary pH value in the patients. Acetohydroxam acid should be used in patients after operative treatment of urolithiasis due to infection with carbamidesplitting bacteria.
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PMID:[Acetylhydroxamic acid in the treatment of nephrolithiasis, caused by infection with urease forming microorganisms]. 269 24

Infection stones have an outstanding position in childhood urolithiasis. In non-infection stones one can mostly find a certain--for example metabolic--causes of stone formation. In infection stones, the urease-producing and thus urea-cleaving properties of some gram-negative bacteria are responsible for alkalization of the urine and lead especially in combination with disturbances of urine transport to the staghorn calculi. Therefore in such children early diagnosis, adequate therapy and consequent maintenance is the crucial point for good life quality in future. Preliminary condition for therapeutic success is a close coworking between pediatric nephrologist, pediatric urologist, family doctor and parents.
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PMID:[Infection-induced urinary calculi in children; current therapeutic schedule and prevention of recurrence]. 307 Jan 41

Acetohydroxamic acid (AHA), a potent urease inhibitor used for treatment of infection-induced struvite urolithiasis, was teratogenic after administration of 25 mg of AHA/kg of body weight/day orally to 5 clinically normal Beagles from the onset of proestrus until parturition. Thirty pups exposed to AHA in utero developed anomalies of the skeletal system, heart, and ventral midline. Cardiac anomalies included atrial septal defects (20%), ventricular septal defects (3%), and atrial and ventricular septal defects (3%). Skeletal anomalies included coccygeal hemivertebrae and fused coccygeal vertebrae (50%), supernumerary vertebrae (67%), supernumerary ribs (50%), duplicated sternebrae (3%), and lumbar hemivertebrae (3%). Defects of the ventral midline of the abdominal wall occurred in 20% of AHA-exposed pups. Other abnormalities included retarded growth, high neonatal mortality, and a decreased number of circulating RBC, compared with those in 30 control pups born to 5 Beagles given a placebo. Adverse effects of AHA in pregnant Beagles were limited to morphologic alterations (Howell-Jolly bodies, spherocytes, and target cells) in a small number of circulating RBC. Slight neutrophilic leukocytosis and monocytosis occurred between 0 and 30 days of pregnancy in dogs given AHA, compared with those in controls. Seemingly, AHA did not influence fertility, conception rate, or length of gestation.
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PMID:Teratogenic effect of acetohydroxamic acid in clinically normal beagles. 380 Jan 19

100 cases of urolithiasis in children treated in Pediatric Clinic of National Research Institute of Mother and Child in the period of 1976-1979 were analized . In 93 children the cause of urolithiasis was established. The most of them (31%) are cases of infection induced urinary stones. Among other reasons of urolithiasis the most common are: metabolic reasons in 26%, probably metabolic reasons in 13%, idiopathic oxalic lithiasis in 17% and others in 6%. At the moment of urolithiasis diagnosis in 94 children bacteriological investigations were done. In 54 cases, i.e. 57,4% infections of the urinary tract were found. 57,8% of boys and 62,2% of girls had urinary tract infections. The most frequent bacteria was urease producting Proteus sp. During 3 years of observation urinary tract infections in 67 children were found. Among bacteria causing the reinfections the most frequent were: Pseudomonas aeruginosa (25,4%), Klebsiella sp. (22,4%), Proteus sp. (19,9%) and E. coli (15%). In 9 cases the bacteriological analysis of removed stones were done. In 2 cases bacteria causing the infection were isolated from the stones, since they were not present in urine any more.
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PMID:[Urinary tract infections and urolithiasis]. 642 22

This case is typical of recurrent urolithiasis managed by repeated surgery. Retrospective assessment of the disorder indicates the need for quantitative analyses of uroliths removed by cystotomy. Compliance of the owners with recommendations to minimize recurrent urolithiasis might have been beneficial. Results of medical therapy designed to induce dissolution of uroliths in this case are representative of preliminary findings of medical dissolution of naturally occurring struvite uroliths in ten other cats. It is of interest that the uroliths dissolved even though no effort was made to induce diuresis. The underlying cause of UTI in this patient may have been damage to the lower urinary tract induced by previous diagnostic and therapeutic procedures and/or sterile struvite uroliths that compromised local host defense mechanisms. Lack of urease production by the uropathogens suggests that they did not play a causative role in formation of uroliths. The need for preventative therapy of recurrent formation of uroliths after their medical dissolution is worthy of further comment. In this patient, specific measures to prevent urolith recurrence were not initiated because it is a part of a prospective clinical study. In the event uroliths recur, medical therapy designed to induce dissolution of uroliths would be repeated. Need for long-term preventative therapy would be dependent on the time interval between recurrent episodes (weeks, months, or years), and the effectiveness of medical therapy for urolith dissolution. Long-term prophylactic therapy would include urine acidifiers and diets low in magnesium.
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PMID:Medical management of male and female cats with nonobstructive lower urinary tract disease. 642 25


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