Biomonitoring of N-nitroso compounds, nitrite and nitrate in the urine of Egyptian bladder cancer patients with or without Schistosoma haematobium infection

The excretion of nitrate, nitrite, apparent total N-nitroso compounds and v olatile nitrosamines was measured in 24 hr urine from 61 Egyptians, divided into 4 groups: controls, Schistosoma haemotobium-infected patients and bla dder cancer patients with and without a history of schistosomal infection. Urinary nitrate in S. haematobium-infected patients was significantly highe r than in the other 3 groups. Nitrite was below the detection limit of the method (less than or equal to 0.015 mu g/mg creatinine) in all but one of t he control samples. S. haemotobium infection significantly increased urinar y nitrite to 0.9 +/- 1.16 mu g/mg creatinine (mean +/- SD, p = 0.001). In b oth bladder cancer groups, nitrite was about 20 times that in S. haematobiu m infected patients without bladder cancer. Excretion of apparent total N-n itroso compounds paralleled that of nitrite. Overall, a good correlation wa s observed between these 2 variables (r = 0.71, p = 0.0001). N-nitrosodimet hylamine was present in all the samples analyzed. S. haematobium infection significantly increased urinary N-nitrosodimethylamine level compared with that of controls (4.02 +/- 1.61 and 2.04 +/- 2.97 ng/mg creatinine, respect ively, p = 0.01). Among cancer patients, N-nitrosodimethylamine was higher than in controls only in those with schistosomal infection. The presence of N-nitroso compounds and N-nitrosodimethylamine in the urine of S. haematob ium-infected patients both before and after the development of cancer, and the observation that these compounds also occur in bladder cancer patients with no history of schistosomal infection, suggest that these compounds mig ht have a role not only in the initiation of the carcinogenic process, but also in its progression. (C) 1999 Wiley-Liss, Inc.