NITRATE, NITRITE AND VOLATILE N-NITROSO COMPOUNDS IN THE URINE OF SCHISTOSOMA-HAEMATOBIUM AND SCHISTOSOMA-MANSONI-INFECTED PATIENTS

The present study presents, for the first time, the amounts of nitrate , nitrite and volatile N-nitroso compounds in saliva and urine samples of Schistosoma haematobium and Schistosoma mansoni infected patients. Mid-morning saliva and 24 h urine samples were collected from male pa tients infected with S.haematobium (n = 129 saliva and 79 urine sample s) and S.mansoni (n = 64 saliva and 65 urine samples) and in a compara tive control group of healthy individuals (n = 27) from the Nile Delta region of Egypt. Saliva samples were analyzed for the presence of nit rate and nitrite; while urine samples were analyzed for the presence o f nitrate, nitrite and volatile N-nitroso compounds. In the control gr oup, N-nitroso-dimethylamine (NDMA) was detected at concentrations (me an +/- SD) of 0.27 +/- 0.47 mu g/day. N-nitrosopyrrolidine (NPIP; 0.6 mu g/day) and N-nitrosopyrrolidine (NPYR; 0.4 mu g/day) were also pres ent in one sample. S.mansoni infected subjects showed significantly (P < 0.001) higher levels of 2.9 +/- 2.9 mu g/day NDMA and a higher freq uency of NPIP (in 40/65 samples; 0.4 +/- 0.3 mu g/day) and NPYR occurr ence (in 59/65 samples; 0.9 +/- 0.9 mu g/day). Significant further inc reases in the excretion of volatile N-nitroso compounds were found in S. haematobium-infected patients with mean daily excretion of 19.2 +/- 21 mu g/day NDMA (in all samples; P < 0.001), 1.6 +/- 2.3 mu g/day NP IP (in 56/79 samples; P < 0.001) and 1.3 +/- 1.9 mu g/day NPYR (in 58/ 79 samples; P < 0.1). The differences either in salivary nitrite/nitra te or in urinary nitrite between the three distinct groups were not si gnificant. However, the urinary excretion of nitrate was elevated from 139 +/- 82 mg/day in the control group to 249 +/- 126 mg/day in S.man soni infected patients (P < 0.001) and to 174 +/- 176 mg/day in S.haem atobium infected subjects (P < 0.005 in comparison to S.mansoni infect ed group). These results suggest a possible role of N-nitroso compound s in the etiology of schistosome-associated bladder cancer and imply a partial participation of S. mansoni in the multistage process of urin ary schistosomiasis-associated bladder carcinogenesis.