Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.4.6 (urease)
 7,490 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

Renal stone formation can be caused by many different and varied disturbances, some of which are poorly understood. The relationship between urinary infection and renal stone formation has not been completely clarified. It is argued that renal stones form primarily as a consequence of the hydrolysis of urea by the bacterial enzyme urease. However, no explanation is given for microorganisms that produce urease only occasionally or not at all. The question arises as to whether the infection-induced microorganisms might not be playing a double role in renal stone formation by not only producing urease, but also by affecting in vivo urokinase (UK) and sialidase (SA) activity. With this in mind, the effect of Escherichia coli on renal UK and SA activity has been studied in male rats with a normal diet. The renal UK (P = 0.208) and SA (P = 0.2135) activities did not differ significantly between the two kidneys of the same rat. In contrast, when drainage from one kidney of a rat was externally obstructed, the UK and SA activities differed significantly between kidneys (P < 0.015). An increase in UK (r = 0.6456, P < 0.0001) and SA (r = 0.7507, P < 0.0001) activity was observed over time in the obstructed kidney. Subcutaneous injections with E coli reduced the UK activity of the obstructed kidney significantly (p = 0.017). However, the SA activity remained the same (P = 0.3929).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pyelonephritis: renal urokinase and sialidase (neuraminidase) activity in rats fed a standard laboratory diet. 807 42

Many hypotheses have been proposed for renal stone formation. It has been argued that with infection-induced renal stones the hydrolysis of urea by bacterial urease increases urinary pH, with consequent stone formation. Unfortunately, this theory is not applicable to the micro-organisms that do not produce urease (e.g. Escherichia coli). It has been recently reported that E. coli reduces the urinary urokinase activity of male rats, but does not influence the urinary sialidase activity. This study has now been expanded to the urease-producing bacteria Proteus mirabilis, Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa and Micrococcus luteus. Subcutaneous injections with these bacteria were found to significantly (P < 0.003) reduce the UK activity of extrarenally obstructed kidneys. The urease-producing mammalian skin bacterium, M. luteus, was, however, the exception (P = 0.1079). In contrast to S. epidermidis, P. aeruginosa and M. luteus (P < 0.0213), P. mirabilis and S. aureus had no effect on renal sialidase activity (P < 0.4047). These results may explain why Proteus species are predominant in infection-induced renal stones. According to the urokinase-sialidase hypothesis, a decrease in urinary urokinase activity should increase the uromucoid levels, whilst no effect on the urinary sialidase activity should favour conversion of urinary uromucoid to mineralizable matrix. These conditions may lead to renal stone formation. An increase in urinary pH resulting from urease-producing micro-organisms will increase salt precipitation on the uromucoid. It is thus concluded that urease-producing bacteria may play a double role in renal stone formation.
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PMID:In vivo effects of urease-producing bacteria involved with the pathogenesis of infection-induced urolithiasis on renal urokinase and sialidase activity. 883 91