Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034186 (pyelonephritis)
 6,144 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The contribution of nitric oxide to host resistance to experimental pyelonephritis is not well understood. We examined whether the inhibition of nitric oxide synthesis alters the sensitivity of lipopolysaccharide (LPS) responder (C3H/HeN) and nonresponder (C3H/HeJ) mice to experimental Escherichia coli pyelonephritis. C3H/HeJ and C3H/HeN mice were implanted subcutaneously with minipumps containing an inhibitor of nitric oxide, NG-nitro-L-arginine methyl ester (L-NAME), or a corresponding vehicle. Ascending urinary tract infection by bladder catheterization with two strains of E. coli, an O75 strain bearing Dr fimbriae and an O75 strain bearing P fimbriae, was developed in tested animals. Twenty-four hours following bladder infection, the kidneys of C3H/HeN and C3H/HeJ mice were colonized at a similar rate. However, 5 weeks postinoculation, C3H/HeN mice cleared infection while C3H/HeJ mice showed persistent colonization. Twenty-four hours following infection, C3H/HeN mice treated with L-NAME showed no significant increase of renal tissue infection compared to the saline-treated control group. However, L-NAME-treated C3H/HeJ mice showed an approximately 100-fold increase in E. coli infection rate compared to the saline-treated controls in the Dr+ group but showed no change compared to those in the P+ group. Dissemination of Dr+ E. coli but not P+ E. coli to the liver and uterus was significantly enhanced with L-NAME treatment in C3H/HeJ mice only. Nitric oxide had no direct killing effect on E. coli in vitro. Nitrite production by various organs was found to be significantly lower in C3H/HeJ mice than in C3H/HeN mice. Alteration of nitric oxide and LPS responsiveness was significantly associated with the increased sensitivity of C3H/HeJ mice to experimental Dr+ but not to P+ E. coli pyelonephritis. These findings are consistent with the hypothesis that nitric oxide synthase activity in concert with LPS responsiveness may participate in the antibacterial defense mechanisms of the C3H mouse urinary tract. This phenomenon is strain dependent and possibly related to the invasive properties of E. coli.
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PMID:Inverse relationship between severity of experimental pyelonephritis and nitric oxide production in C3H/HeJ mice. 1022 4

Pyelonephritis is a risk factor for renal tubular epithelial cell damage in children. The inter- and intracellular regulator nitric oxide (NO) plays a role in the modulation of cellular viability in urinary tract infections, but the role of the NO pathway in renal proximal tubular-cell death remains unclear. The present study demonstrates that, in renal epithelial cells undergoing death mediated by Escherichia coli strain ARD6 serotype O6K13H1 (O6), levels of the phosphorylated extracellular signal-regulated kinase (ERK) 1/2 and inducible NO synthase (iNOS) proteins are up-regulated, but levels of endothelial NO synthase are down-regulated. When NO synthase (NOS) activity is inhibited by the specific inhibitor of NOS or mitogen-activated protein kinase kinase, cells are prevented from death. Moreover, down-regulating protein 53 (p53) does not prevent the cells from dying, although p53 is up-regulated in O6-exposed cells. Up-regulation of heme oxygenase (HO)-1 by sodium nitroprusside or by the specific activator hemin inhibits cell death. In conclusion, the activation of ERK mediates O6 toxin-mediated renal cell death via induction of iNOS. Stimulation of HO-1 protects cells against death.
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PMID:Activation of extracellular signal-regulated kinase mediates apoptosis induced by uropathogenic Escherichia coli toxins via nitric oxide synthase: protective role of heme oxygenase-1. 1519 52