Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

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

Growing steers were used in a replicated 3 X 3 Latin square to study the influence of ionophores on mineral metabolism and ruminal urease activity. Treatments consisted of: 1) basal high energy diet; 2) basal plus 33 ppm lasalocid and 3) basal plus 33 ppm monensin. Each period was 33 days and apparent absorption and retention of macrominerals were measured during the last 5 days of each period. Mineral intake during the collection period was not affected by treatment. Both ionophores increased apparent absorption of sodium, magnesium and phosphorus. Retention of magnesium and phosphorus were higher for steers receiving either lasalocid or monensin. Potassium and calcium absorption were not significantly affected by treatment. Serum concentrations of macrominerals were similar for all treatments. Zinc and copper concentrations in serum were higher in animals fed monensin or lasalocid. Steers fed either ionophore had lower concentrations of soluble potassium and calcium in rumen fluid. Both ionophores also decreased ruminal osmolality. Bacterial urease, a nickel-dependent enzyme, was decreased by 28 and 66% in animals that received lasalocid and monensin, respectively. These findings indicate that lasalocid and monensin affect metabolism of certain minerals in ruminants.
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PMID:Influence of monensin and lasalocid on mineral metabolism and ruminal urease activity in steers. 669 34

In an analysis, by both crystallographic and microbiological methods, of 50 urinary calculi recently removed by surgical operation, 33 proved to be of metabolic origin (mostly calcium oxalate and some uric acid or urate) and 17 of 'infective' origin (struvite, apatite or a mixture of the two). Metabolic stones were usually bacteriologically sterile or contained only small numbers (less than 10(3)/g of stone) of bacteria which did not produce urease, while infective stones always contained urease-producing organisms, usually Proteus mirabilis, in large numbers (greater than 10(5)/g). The combined approach of stone analysis by crystallography and microbiological culture yields more information than conventional techniques on which to base the treatment of urinary calculi and the prevention of their recurrence.
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PMID:Bacteriological and crystallographical analysis of urinary calculi: aid to patient management. 673 6

Understanding of the bacterial contribution to urinary calculi has been limited to those organisms capable of altering the urine through urease activity. Sterilized urines from stone forming and non-stone forming individuals were inoculated with bacteria having either strong, weak, or no urease activity. All organisms grown in unbuffered urines produced crystallization (calcite or apatite) as demonstrated by X-ray diffraction. Bacteria grown in conventional medium (Heart Infusion broth) did not demonstrate crystal formation. Unstained specimens revealed electron-dense deposits within bacteria grown in urine. Deposits were not present in organisms grown in conventional media. Analysis revealed increased levels of calcium within these deposits as compared to extracellular levels. These findings support the hypothesis that both urease producing an non-urease producing organisms may accumulate calcium crystals intracellularly and form nidi for calculus formation.
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PMID:Intracellular crystal formation in bacteria from human urines: a contributing factor in urinary calculi. 701 65

The effect of bacterial infection on excised renal papillae as a model for papillary necrosis and subsequent calcification was investigated. Sterile rat renal papillae were placed in 25 ml aliquots of filter sterilized human urine and then inoculated with one ml suspensions of sterilized human urine and then inoculated with one ml suspensions of sterile saline as a control, or 1 x 108/ml Escherichia coli or proteus mirabilis. After incubation at 37 degrees C for periods of 8 hr, 24 hr, 48 hr, 72 hr, 1 wk, 2 wk and 3 wk, urinary pH was measured, bacterial culture performed and the renal papillae were recovered and examined by scanning electron microscopy (SEM) and energy dispersive spectrophotometry (EDS). In the case of Proteus mirabilis, the sequence of events noted included bacterial-papillary interactions consisting of cell desquamation and strand formation, despite infrequent bacterial attachment. After 10 hr, a rapid, urease induced pH rise resulted in calcium salt deposition on the papillae surface. Organism death was apparent after 72 hr. Escherichia coli infected papillae demonstrated similar cell surface changes after a 8 hr as seen in P. mirabilis; however, frequent evidence of bacterial attachment and penetration was apparent. Bacterial attachment was a prominent feature throughout the incubation period with E. coli. After one week, rare areas of degenerating cells and bacteria with increased calcium levels as compared to surrounding areas were noted by EDS analysis. Urinary pH was stable throughout the incubation period. This study suggests varied roles for the organisms most associated with infection induced papillary necrosis (E coli) and papillary necrosis with subsequent stone formation (P. mirabilis). A role for bacterial calcification in the absence of bacterial urease activity by E. coli is also suggested.
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PMID:Papillary necrosis in vitro: a scanning electron microscopic comparison of escherichia coli and Proteus mirabilis infection. 703 30

A series of 99 consecutively operated patients presenting staghorn stones has been reviewed to ascertain the factors implicated in recurrent calculogenesis. 71.7% of the calculi were infection stones; 50.7% harbored Proteus species bacteria and 33.8% Escherichia coli. Struvite stones were found in 57.6% followed at long distance (18.2%) by carbonate apatite, calcium oxalate (11.1%) and mixed (9.1%) stones. Postoperative assessment revealed 17% residual stones, which enhanced infection in 46.7% of these cases and regrew to form a new dendritic stone in 33.3%; 80% of these repeat stones were struvite. 31.5% of the patients initially freed of their calculi by the operation, had true recurrences, and 56.5% of them had resistant urinary infection, caused by Proteus or E. coli (50%-50%). Progressive growth of the recurrent lithiasis occurred in 61.5% of the infected cases, while 87.5% of the recurrences occurring in patients with sterile urine remained stabilized. In the group of nonrecurring lithiasis (56.8%) only 16% had urinary infection. These results confirm the preponderant role played by infection in the pathogenesis of staghorn "malignant' lithiasis and move the authors to make a plea in favor of postoperative integrated therapy, including the use of long-term antibacterial agents and urease inhibitors.
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PMID:The problem of recurrences and infection after surgical removal of staghorn calculi. 703 22

The analysed material includes 100 children with urolithiasis treated in the Pediatric Clinic of the National Research Institute of Mother and Child in Warsaw between 1976 and 1978. Patients' age was from 3 months to 18 years. The analysed group included 51 boys and 49 girls. Urinary tract infection was found in 54 cases, i.e. 57,4% of the analysed material. The most common bacterial strains were those producing urease. They were detected in 48 children i.e. 88,9% of cases with urinary tract infection. Mostly these were bacteria of Proteus group--sporadically Pseudomonas aeruginosa and Staphylococcus albus. In the analysed patients urinary tract obstruction was observed in 36 children, i.e. 36% of cases. In 77% of the analysed material, localization of concrements was in upper urinary tract in 19% in the ureters and in 4% in the lover urinary tract. While in adult patients the most common compound of urinary stones was calcium oxalate, in children the most common stone compounds were phosphates (found in 38 cases i.e. 58,4% of the analysed material). The second frequent compound was oxalate found in 20 cases (30,7%). Less frequent compounds were uric acid and cystine. Performed study allowed to establish the cause of urolithiasis in 93 out of 100 examined children. Metabolic reasons of urolithiasis were found in 26 cases, i.e. 26% of the analysed material. They were as follows: idiopathic hypercalciuria--12 cases, uric acid urolithiasis--8 cases, primary hyperoxaluria--3 cases, cystinuria--2 cases, and incomplete acidosis of distal renal tubuli--1 case. Urolithiasis of probably metabolic origin was detected in 13 children (13%). Other reasons of urolithiasis in children were: infection (31%), idiopathic urolithiasis (17%) and others (6%). In 7 cases the reason of urolithiasis was not established.
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PMID:[Metabolic etiology of urinary calculi in children]. 717 91

Previous theoretical analysis has indicated that adequate mass transfer is possible in a dialyzer with reciprocating membrane motion provided that the dialysate concentration of uremic substances is kept low. Earlier models have utilized a collection of sorbents (charcoal, urease, and a cation exchanger) constrained next to the dialyzer membranes. We have designed a new dialyzer with a sorbent suspension having free access from a reservoir to the spaces between membrane packages. At a treatment rate of 150 ml/min/m2, the in vitro creatinine clearance is 75 ml/min/m2, which agrees within experimental accuracy with the theoretical prediction. The creatinine clearance, flow resistance, and compliance of the dialyzer are constant during four to six hours of testing. In vivo tests have been performed during urea and creatinine infusion in a normal dog and in a dog with 3/4 nephrectomy. The in vivo creatinine clearance agrees within 10% with the in vitro clearance. Sodium, potassium, calcium, and bicarbonate fluxes are acceptable for patients in renal failure. The new design allows a higher capacity for urea and creatinine, since larger amounts of sorbent may be used.
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PMID:A reciprocating, single-needle hemodialyzer with bidirectional flow of sorbent suspension. 718 27

A simple and inexpensive procedure for determination of microgram quantities of metal ions in proteins is described and tested with nickel and iron. The method involves (a) dry ashing in an oxygen atmosphere at 450-460 degrees C in Pyrex vessels, (b) conversion of the metal oxides or other compounds to readily soluble species, and (c) spectrophotometric analysis. An improved procedure for the direct spectrophotometric determination of nickel using dimethylglyoxime is accurate to +/- 2% or better with samples of 1-5 microgram of nickel. These techniques were used to determine that the nickel content of freshly prepared jack bean urease in 2.00 +/- 0.12 g-at./96 600 g protein. The corresponds to 2.0 nickel ions per subunit. This result was confirmed by atomic absorption analysis, which also showed that calcium, manganese, cobalt, and iron are not present in significant amounts in urease.
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PMID:Jack bean urease (EC 3.5.1.5). I. A simple dry ashing procedure for the microdetermination of trace metals in proteins. The nickel content of urease. 727 35

Magnesium ammonium phosphate calculi developed in the urinary bladders and urethras of four of five offspring of Miniature Schnauzer parents with recurrent struvite urolithiasis. Calculi were detected by radiograhy when the dogs were 12 to 15 months old. Males and females were affected. A significant number of urease-producing staphylococci were identified in the urine of three of four dogs before urolith formation, and in one dog after urolith formation. The dogs were evaluated until they were 26 months old. Serum concentrations of calcium, phosphorus, and magnesium were inside usual limits throughout the study. Abnormalities that might predispose to urinary tract infection were not identified by radiography or necropsy studies. In one dog, bladder calculi recurred after surgical removal of multiple cystoliths. In another, urethral obstruction and acute generalized pyelonephritis induced a lethal uremic crisis. Gross and microscopic lesions, detected after necropsy of all dogs with uroliths, were typical of bacterial infection.
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PMID:Struvite urolithiasis in a litter of miniature Schnauzer dogs. 740 90


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