The role of nitrate, nitrite and N-nitrosamines in carcinogenesis of colon tumours following ureterosigmoidostomy
✍ Scribed by K�lble, T. ;Tricker, A. R. ;M�hring, K. ;Berger, M. R. ;Geiss, H. ;Staehler, G.
- Publisher
- Springer
- Year
- 1990
- Tongue
- English
- Weight
- 744 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0300-5623
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✦ Synopsis
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.