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Correlation between the frequency of structural chromosome aberrations and duration of occupational exposure to ionising radiation
280
Abstracts / Mutation Research 360 (1996) 201-300
formation of nitrite, the potency of nitrosation and the genotoxic activity were tested. Parameter as nitrate concentration, the water flow rate in the system, nitrite and morpholine addition and the pH value were checked. For testing the potency of nitrosation ad formation of nitrite in the reactor we took Morpholin, a fast nitrosing amine. For the break down rate of nitrate, there was no influence of the initial nitrate concentration, the nitrite addition and the water flow rate in the system, pH values below 5.5 showed a little break down rate of nitrate. There was no correlation between the starting point of nitrate concentration and the formation of nitrite, although there was a positive correlation between the length of stay and the formation of nitrite. Nitrite and morpholine concentrations of 10 and 5 ppm showed no detectable formation of nitrosomorpholine. The analysis of different water tests in the construction did not show significant results for DNA damage by the sister-chromatid exchange (SCE). The results of the Salmonella microsome assay (tester strains TA98, TA100 with and without S9mix) didn't show any mutagenic effects relating to the potency of nitrosation. According to our experiments the potency of generalising nitrosamides or nitrosamines by drinking water denitrification seems to be low. There is no final assessment of detriment to health by denitrifying drinking water.
was examined in 66 persons from a department of nuclear medicine. During the last year the examinees were exposed to a dose from 0 to 11.6 Gy. By single urine sampling, the 131j activity was measured in the urine of up to 78.66 B q / g . The examinees were placed into two groups, one which included those with to 10 years of employment and another with more than 10 years of employment. The total number of chromosome aberrations in the first group was 0.026 per cell and in the second 0.03 per cell. Comparison the frequency of chromosome and chromatid breaks, acentric fragments and bicentric chromosomes between the two groups failed to show a significant difference. The results agree with state of art data on the life span of lymphocytes which carry asymmetric structural changes of chromosomes considering duration of exposure to ionising radiation. Only in the case of a balanced chronic exposure it might be possible to detect an increased frequency of chromosome aberrations which is not connected with total cumulative dose, but is the consequence of additional dose of ionising radiation. 7-20
Evaluation of the in vivo genotoxic potential of 3 carcinogenic aromatic amines using the Big Blue transgenic mouse mutation assay
7-19
Correlation between the frequency of structural chromosome aberrations and duration of occupational exposure to ionising radiation D. Kubelka; Institute for medical research and occupational health Zagreb, Ksaverska c.2, P.O. Box 291, Croatia The chromosome aberration assay is still the most widely used method in the biodosimetry of a population exposed to ionising radiation. In order to detect a possible cumulative genotoxic effect of long-term occupational exposure to ionising radiation the frequency of chromosome aberrations
F. Locher, R. Ahiabor, B. Blanco, F. Mantovani, M. Robinson, G. Sreenan, F. St~idtler, W. Suter; Drug Safety, Toxicology, Sandoz Pharma Ltd., CH-4002 Basel, Switzerland In the Big Blue transgenic mouse mutagenesis assay mutations within the lacl target gene can be identified by infecting restriction-deficient host E. coli with the packaged phage and plating on indicator agar containing X-gal. Phage plaques containing mutated lacI targets appear blue on the indicator plates, while phage containing non-mutated targets are colourless. The ratio of blue plaques to the total number of plaques is an indication of the mutagenic potential of the test compound. The gene is highly sensitive to missense mutations, and it has been widely studied as a target for mutagenesis. Further-
Abstracts / Mutation Research 360 (1996) 201-300
formation of nitrite, the potency of nitrosation and the genotoxic activity were tested. Parameter as nitrate concentration, the water flow rate in the system, nitrite and morpholine addition and the pH value were checked. For testing the potency of nitrosation ad formation of nitrite in the reactor we took Morpholin, a fast nitrosing amine. For the break down rate of nitrate, there was no influence of the initial nitrate concentration, the nitrite addition and the water flow rate in the system, pH values below 5.5 showed a little break down rate of nitrate. There was no correlation between the starting point of nitrate concentration and the formation of nitrite, although there was a positive correlation between the length of stay and the formation of nitrite. Nitrite and morpholine concentrations of 10 and 5 ppm showed no detectable formation of nitrosomorpholine. The analysis of different water tests in the construction did not show significant results for DNA damage by the sister-chromatid exchange (SCE). The results of the Salmonella microsome assay (tester strains TA98, TA100 with and without S9mix) didn't show any mutagenic effects relating to the potency of nitrosation. According to our experiments the potency of generalising nitrosamides or nitrosamines by drinking water denitrification seems to be low. There is no final assessment of detriment to health by denitrifying drinking water.
was examined in 66 persons from a department of nuclear medicine. During the last year the examinees were exposed to a dose from 0 to 11.6 Gy. By single urine sampling, the 131j activity was measured in the urine of up to 78.66 B q / g . The examinees were placed into two groups, one which included those with to 10 years of employment and another with more than 10 years of employment. The total number of chromosome aberrations in the first group was 0.026 per cell and in the second 0.03 per cell. Comparison the frequency of chromosome and chromatid breaks, acentric fragments and bicentric chromosomes between the two groups failed to show a significant difference. The results agree with state of art data on the life span of lymphocytes which carry asymmetric structural changes of chromosomes considering duration of exposure to ionising radiation. Only in the case of a balanced chronic exposure it might be possible to detect an increased frequency of chromosome aberrations which is not connected with total cumulative dose, but is the consequence of additional dose of ionising radiation. 7-20
Evaluation of the in vivo genotoxic potential of 3 carcinogenic aromatic amines using the Big Blue transgenic mouse mutation assay
7-19
Correlation between the frequency of structural chromosome aberrations and duration of occupational exposure to ionising radiation D. Kubelka; Institute for medical research and occupational health Zagreb, Ksaverska c.2, P.O. Box 291, Croatia The chromosome aberration assay is still the most widely used method in the biodosimetry of a population exposed to ionising radiation. In order to detect a possible cumulative genotoxic effect of long-term occupational exposure to ionising radiation the frequency of chromosome aberrations
F. Locher, R. Ahiabor, B. Blanco, F. Mantovani, M. Robinson, G. Sreenan, F. St~idtler, W. Suter; Drug Safety, Toxicology, Sandoz Pharma Ltd., CH-4002 Basel, Switzerland In the Big Blue transgenic mouse mutagenesis assay mutations within the lacl target gene can be identified by infecting restriction-deficient host E. coli with the packaged phage and plating on indicator agar containing X-gal. Phage plaques containing mutated lacI targets appear blue on the indicator plates, while phage containing non-mutated targets are colourless. The ratio of blue plaques to the total number of plaques is an indication of the mutagenic potential of the test compound. The gene is highly sensitive to missense mutations, and it has been widely studied as a target for mutagenesis. Further-