The role of nitrate, nitrite and N-nitrosamines in carcinogenesis of colon tumours following ureterosigmoidostomy.
Urinary diversion in both a rat model for ureterosigmoidostomy and in ureterosigmoidostomy patients result in an increased incidence of colon tumours. Bacterial and chemical investigations on feces-urine mixtures from both the rat model and ureterosigmoidostomy patients showed the presence of a complex nitrate-reducing bacterial flora in both rats and humans. This bacterial flora actively reduced urinary nitrate to nitrite in humans and increased the endogenous formation of N-nitroso compounds. No evidence of urinary nitrate reduction and increased nitrosamine formation in the rectosigmoid of rats was found. The results support the N-nitrosamine theory of carcinogenesis of the colon following ureterosigmoidostomy in humans, but not in rats. As the rat model induces colon carcinomas, factors other than the increased endogenous formation of N-nitroso compounds in the rectosigmoid may contribute to the initiation of colon carcinomas following ureterosigmoidostomy.
Kälble
T
T
Urological Department, University of Heidelberg, FRG.
Tricker
A R
AR
Möhring
K
K
Berger
M R
MR
Geiss
H
H
Staehler
G
G
D000818:Animals; D001419:Bacteria / Q000378:metabolism; D003106:Colon / Q000378:metabolism / Q000382:microbiology; D003110:Colonic Neoplasms / Q000209:etiology*; D005243:Feces / Q000032:analysis; D006801:Humans; D009566:Nitrates / Q000378:metabolism / Q000652:urine; D009573:Nitrites / Q000378:metabolism / Q000652:urine; D009602:Nitrosamines / Q000378:metabolism*; D051381:Rats; D014547:Urinary Diversion / Q000009:adverse effects* / Q000379:methods
D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines