Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lowering supersaturation with respect to struvite and carbonate apatite is the most important prophylactic measure in patients with infection-induced kidney stone disease. This is best achieved by combining culture-specific antibiotics with urinary acidification. Urinary infection with non-urease-producing Escherichia coli, probably promoting struvite particle formation, must be eradicated. Possible measures for improving urothelial anti-adherence properties or reducing bacterial adherence are discussed.
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PMID:Prophylaxis of infection-induced kidney stone formation. 229 Dec 50

Struvite stones are formed as the result of urinary tract infection by urease-producing bacteria. Ultrastructural examination of calculi removed from a patient revealed bacteria incorporated throughout the stone matrix. Exopolysaccharide stained by ruthenium red was associated with most of the bacteria, but it represented only a small portion of the organic matrix in the stone. Localised deposits of calcium and phosphorus, components of carbonate-apatite, and magnesium, a struvite component, were detected in close proximity to the cells. Histochemical examinations revealed that several of the gram-negative bacteria within the stone matrix possessed high levels of urease activity. We propose that bacterial slime production, intimately involved in the initiation of stone matrix deposition, is less prominent in mature stones because of the increased incorporation of host-derived mucoproteins and mucopolysaccharides.
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PMID:Observations of the ultrastructure of infected kidney stones. 247 Sep 5

The development of a large vaginal stone in a 25-year-old female, correlated with vesicovaginal fistula, is presented. The stone, composited of struvite and carbonate apatite, formed around non-absorbable surgical suturing material in urine with urease producing (P. mirabilis) bacterial infection. The stone was removed by simple lithotripsy technique. Attention is taken for the importance of stone prevention.
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PMID:[Giant secondary vaginal calculus]. 259 61

Infection-induced stones in man probably form solely as a consequence of urealysis which is catalyzed by the bacterial protein urease. Urease stones composed of struvite and carbonate-apatite may form primarily, or as secondary stones or pre-existent metabolic stones. Struvite stones form and grow rapidly owing to (a) supersaturation of urine with stone forming salts, (b) 'salting out' of poorly soluble organic substances normally dissolved in urine and (c) ammonia-induced destruction of the normally protective urothelial glycosaminoglycan layer. Immature (predominantly organic) matrix stones mature into densely mineralized stones. Curative treatment is possible only by eliminating all of the stone and by eradicating all urinary and parenchymal infection. A variety of operative and pharmaceutical approaches are available. Patient treatment must be individualized inasmuch as some patients are better candidates for one type of treatment than another.
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PMID:Infection (urease) stones. 330 21

In a non-recirculating system of isolated liver perfusion, stimulation of urea synthesis by NH4Cl is followed by a decrease of effluent pH by up to 0.2 pH unit. This effect is not observed when urea synthesis is inhibited by amino-oxyacetate or norvaline. When the urea formed by the liver is immediately hydrolysed with urease before the effluent perfusate reaches the pH electrode, the urea-synthesis-induced acidification is no longer observed. This indicates that accompanying alterations in hepatic metabolism after stimulation of urea synthesis, such as increased energy provision and consumption, are not responsible for the extracellular acidification, but that the effect is due to the formation of urea itself. The acidification of the extracellular space after stimulation of urea synthesis by NH4Cl is quantitatively explained by the consumption of 2 mol of HCO3-/mol of urea formed: 1 mol being incorporated into urea, the other being protonated to yield CO2 and H2O. The data match the theoretically predicted HCO3- consumption during ureogenesis and underline the role of hepatic urea synthesis for disposal of HCO3- by converting it into the excretable products CO2 and urea.
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PMID:The effect of urea synthesis on extracellular pH in isolated perfused rat liver. 379 75

The effect of varying concentrations of either NaCl or Na2CO3 (0, 10, 20, and 25 meq/100 g soil) and organic carbon (0 and 2% starch) on the activity of dehydrogenase, urease, and phosphatase (nuclease) was studied in incubated samples of alluvial clay and calcareous sandy loam soils. Moisture content was kept at 60% W.H.C. The level of 10 meq/100 g soil of either sodium chloride or sodium carbonate was stimulatory for the activity of the three enzymes studied in both soils tested. The increasing concentrations of Na2CO3 showed greater changes in the enzymatic activity than the corresponding concentrations of NaCl in both soils. Application of starch reduced the inhibitory effect of the high levels of such salts on the enzymatic activities in both soils, except for phosphatase which was depressed by Na2SO3 in starch-amended soil samples. The calcareous soil responded to the starch addition less than the alluvial soil.
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PMID:Activity of enzymes in organic carbon-amended soils treated with varying levels of salts. 628 41

Prevention of the formation of struvite and carbonate-apatite calculi, which rapidly increase in size and tend to recur, is of prime importance. One of the urease inhibitors, hydroxycarbamide, was studied in vitro. The results are favourable and justify further studies aimed at the local application of the inhibitor.
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PMID:Applicability of biosuppressin as an urease-inhibitor. 648 Feb 81

Phosphate stones are divided in two groups: I. Infection stones = triple phosphate stones (struvite and carbonate apatite). II. Calcium phosphate stones = Hydroxy apatite. Ad I. For the formation of this stone, infection with urease-producing bacteria is essential. It is important to look for factors that cause infection and for metabolic abnormalities. Three possibilities for treatment are discussed: Acidifying the urine: orally with NH4NO3 or NH4Cl; dosage is possible up to 12 g a day (metabolic acidosis!). Irrigation for instance with Renacidin ; when using a nephrostomy-tube, one can start 5 days after the operation. It is important to look for fever and flank pain. Especially useful in cases with small residual stones. Reduction of phosphate excretion in urine ( Shorr -regimen). Some aluminium combinations reduce the intestinal phosphate absorption as a result of the formation of a nonabsorbable aluminium-phosphate combination. This can be combined with a low calcium- and phosphate diet. In several publications good results are shown. Also when using a less rigid regimen, satisfactory results are seen: decrease of the phosphate excretion from 30 to 17 mmol/24 h (own investigation). Urease-inhibitors result in a lower urine-pH and a decrease of the ammonium-concentration. there are only a few publications with results, but AHA seems able to reduce the stone size in 24% of the patients. Ad II. This stone is concerning formation and treatment much like the calcium oxalate stone. In case of an alkaline urine one must look for primary hyperparathyroidism and renal tubular acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Conservative therapy of phosphate calculi]. 653 26

The occurrence of bacteria and Ureaplasma urealyticum in the upper urinary tract was studied in 50 patients operated on for renal stones. Cultures were performed on voided urine, pelvic urine obtained during surgery and the stone. The chemical composition of the stones was analysed. Twenty-six stones were of metabolic origin and 24 infection-induced, i.e. composed of struvite and/or carbonate-apatite. Ureaplasma urealyticum was cultured from the upper urinary tract in 1 patient with metabolic stones, and in 7 with infection stones. In 4 of these 7 patients no other urease-producing micro-organism was detected, suggesting that Ureaplasma urealyticum may have been associated with stone formation in these patients.
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PMID:Ureaplasma urealyticum and upper urinary tract stones. 654 7

The factors of infective calculus formation and the conditions favoring their prevention were studied by examining in vitro the role of the most common representative of urease-producing bacteria, Proteus mirabilis. The stream of Proteus-containing urine was found to form deposits of magnesium ammonium phosphate, carbonate apatite and ammonium-urate on the glass surfaces. Application either of mandelic acid or of Gentamycin was found to reduce the production of these deposits, and their joint application proved fully preventive to their formation. Gentamycin applied in saline acidified with mandelic acid was capable of dissolving previously formed crystals. A medication of this composition is advocated for preventive use after surgery for staghorn calculi. The necessity for continuing peroral medication and specific antibacterial therapy for months is emphasized.
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PMID:Study of infective (secondary) renal calculus formation in vitro. 702 70


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