Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aristolochic acid (AA) a naturally occuring nephrotoxin and carcinogen is implicated in a unique type of renal fibrosis, designated Chinese herbs nephropathy (CHN). We identified AA-specific DNA adducts in kidneys and in a ureter obtained from CHN patients after renal transplantation. AA is a plant extract of aristolochia species containing AA I as the major component. Aristolactams are the principal detoxication metabolites of AA, which were detected in urine and faeces from animals and humans. They are activated by cytochrome P450 (P450) and peroxidase to form DNA adducts. Using the 32P-postlabelling assay we investigated the formation of DNA adducts by aristolactam I in these two activation systems. A combination of two independent chromatographic systems (ion-exchange chromatography TLC and reversed-phase HPLC) with reference compounds was used for the identification of adducts. Aristolactam I activated by peroxidase led to the formation of several adducts. Two major adducts were identical to adducts previously observed in vivo. 7-(deoxyguanosin-N2-yl)aristolactam I (dG-AAI) and 7-(deoxyadenosin-N6-yl)aristolactam I (dA-AAI) were formed in DNA during the peroxidase-mediated one-electron oxidation of aristolactam I. Aristolactam I activated by P450 led to one major adduct and four minor ones. Beside the principal AA-DNA adducts identified recently in the ureter of one patient with CHN, an additional minor adduct was detected, which was found to have indistinguishable chromatographic properties on TLC and HPLC from the major adduct formed from aristolactam I by P450 activation. Thus, this minor AA-adduct might be evolved from the AAI detoxication metabolite (aristolactam I) by P450 activation. These results indicate a potential carcinogenic effect of aristolactam I in humans.
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PMID:Aristolactam I a metabolite of aristolochic acid I upon activation forms an adduct found in DNA of patients with Chinese herbs nephropathy. 1044 9

Expression of cytochromes P450 CYP1A1, CYP1B1, CYP2E1 and CYP4B1 was analysed on the transcript level in human urothelial cells obtained by various methods. As a source of urothelial cells, exfoliated cells in urine samples were used. Their expression profiles were determined either immediately after centrifugal enrichment (n=4) or after their cultivation and propagation (n=8). Another source of urothelial cells were ureter specimens from surgical subjects (n=4). Generally, expression was most prominent for CYP1B1 and CYP4B1 among the CYP transcripts analysed. CYP1B1 mRNA was detected in all samples investigated except for one ureter specimen. CYP4B1 mRNA was present in cell cultures from three out of eight healthy subjects, in three out of four directly investigated urinary sediments and in the cells of all five ureter specimens of four donors investigated after resection and subsequent cell culture. In most cases, CYP2E1 transcript levels were lower than those of CYP1B1 and CYP4B1. CYP2E1 mRNA was detected in cell cultures of six out of eight healthy subjects, in one out of four urinary sediments and in three out of five ureter specimens. CYP1A1 mRNA was clearly observed only in cells from resected ureters. In cell cultures the relative mRNA expression levels varied with subjects interindividually, intraindividually and also during the time of cell culture. The study demonstrates constitutive mRNA expressions of xenobiotic metabolising CYP enzymes in human urothelial cells obtained by different methods. In particular, transcripts of CYP1B1 and CYP4B1 are present, coding for enzymes which are active in the metabolism of polycyclic aromatic hydrocarbons and arylamines, respectively.
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PMID:Expression of cytochrome P450 enzymes CYP1A1, CYP1B1, CYP2E1 and CYP4B1 in cultured transitional cells from specimens of the human urinary tract and from urinary sediments. 1634 45