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Delayed biological effects of low single doses of aflatoxin B1 in vivo
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cantly higher ( × 1.62) than cells with AN. DMM was also able to induce both effects although at a lesser extent: CA were induced at doses exceeding 4 3 . 4 x 1 0 6 M and AN 1 . 7 3 x 1 0 -6 M. By considering the toxicity instead of the applied dose for the comparison of the genotoxic-induced effects it appears that MMC was 6-fold more effective in inducing CA than DMM. On the other hand, no significant difference was observed between the two compounds in inducing AN. Therefore, MMC is much more clastogenic than DMM, whereas mitotic spindle disturbances appear to be almost equally induced by both compounds. The present cytogenetic analysis reveals that the chemical-biological interactions of the two mercury compounds at the cellular level must be different, MMC being more effective in inducing chromosome damages than DMM at doses that produce comparable general toxic effects.
122 Giromini, L. ~, M. Bulleri 1, B. Barnini l, S. del Ry i, M. Pala 2, F. Valerio 2, R. Barale and I. Barrai, Dipartimento di Biologia Evolutiva, Ferrara, i Dipartimento di Scienza dell'Ambiente e del Territorio, Pisa and 2 lstituto di Igiene e da Medicina Preventiva, Genoa (Italy) Mutagenicity analysis of airborne particles and their three fractions in 17 Italian towns
Organic extracts and their three fractions: acid, basic and neutral (polar, non-polar and polycyclic aromatic hydrocarbons, PAH) from airborne particles collected in 17 Italian towns (January-April, 1990) were tested for mutagenicity on Salmonella strains TA98, TA100 ( ± $ 9 ) , TA98NR and T A 9 8 / 1 , 8 D N P 6 by means of the Ames test. Mutagenic responses were fitted by an equation which also takes into account toxic effects on tester organisms. The TA98 strain usually gave the greatest increases of revertants over the control level. In general, the addition of $9 resulted in a significant mutagenicity of the crude extract and to a lesser exent of the acid and basic fractions. For the PAIl fraction the presence of $9
was strictly required, as expected. The neutral polar (without $9) fraction was by far the most active whereas the non-polar fraction exhibited negligible mutagenicity. No dramatic decreases of mutagenicity were observed with the NR derivative strains. By adding the mutagenic activity of the three fractions we obtained 20-70% (without $9) and 30-70% ( + $9) of the crude extract activity, suggesting that a proportion of mutagens are lost during fractionation. During air sampling, temperature, atmospheric pressure, light, wind strength and direction, SO 2, CO, NO 2, 0 3 and non-methanic hydrocarbon concentrations were continuously monitored. Meteorological and chemical variables, except total suspended matter, seem not to be correlated significantly with mutagenicity.
123 Bfirta, 1., T. Petr, B. Turek, P. Hrabal, J. Pro~ek and K. Kejlovfi, 3rd Medical Faculty, Charles University and Institute of Hygiene and Epidemiology, Prague (Czechoslovakia) Delayed biological effects of low single doses of aflatoxin B t in vivo
The aim of this work was to compare the time intervals from demonstration of free AFB t in body organs to the appearance of genotoxic damage to cells and the development of manifest carcinogenic changes in vivo in the Chinese hamster ( Cricetulus griseus ). Free AFB t after a single i.p. dose of 0.1 mg AFB~/kg was detected in blood, liver, kidneys and testis within 8-10 h after injection. In subsequent time intervals the concentration of free AFB I was below the detection threshold of the RIA method. Genotoxic effects could be proved by the increasing frequency of chromosomal aberrations in the bone marrow cells detectable from 3 h after AFB l administration. These aberrations tended to persist (depending on the mode of application) up to 60 weeks (in the case of Macaca mulatta monkeys up to 2 years). The minimal effective genotoxic dose was 0.1 ~g A F B l / k g .
cantly higher ( × 1.62) than cells with AN. DMM was also able to induce both effects although at a lesser extent: CA were induced at doses exceeding 4 3 . 4 x 1 0 6 M and AN 1 . 7 3 x 1 0 -6 M. By considering the toxicity instead of the applied dose for the comparison of the genotoxic-induced effects it appears that MMC was 6-fold more effective in inducing CA than DMM. On the other hand, no significant difference was observed between the two compounds in inducing AN. Therefore, MMC is much more clastogenic than DMM, whereas mitotic spindle disturbances appear to be almost equally induced by both compounds. The present cytogenetic analysis reveals that the chemical-biological interactions of the two mercury compounds at the cellular level must be different, MMC being more effective in inducing chromosome damages than DMM at doses that produce comparable general toxic effects.
122 Giromini, L. ~, M. Bulleri 1, B. Barnini l, S. del Ry i, M. Pala 2, F. Valerio 2, R. Barale and I. Barrai, Dipartimento di Biologia Evolutiva, Ferrara, i Dipartimento di Scienza dell'Ambiente e del Territorio, Pisa and 2 lstituto di Igiene e da Medicina Preventiva, Genoa (Italy) Mutagenicity analysis of airborne particles and their three fractions in 17 Italian towns
Organic extracts and their three fractions: acid, basic and neutral (polar, non-polar and polycyclic aromatic hydrocarbons, PAH) from airborne particles collected in 17 Italian towns (January-April, 1990) were tested for mutagenicity on Salmonella strains TA98, TA100 ( ± $ 9 ) , TA98NR and T A 9 8 / 1 , 8 D N P 6 by means of the Ames test. Mutagenic responses were fitted by an equation which also takes into account toxic effects on tester organisms. The TA98 strain usually gave the greatest increases of revertants over the control level. In general, the addition of $9 resulted in a significant mutagenicity of the crude extract and to a lesser exent of the acid and basic fractions. For the PAIl fraction the presence of $9
was strictly required, as expected. The neutral polar (without $9) fraction was by far the most active whereas the non-polar fraction exhibited negligible mutagenicity. No dramatic decreases of mutagenicity were observed with the NR derivative strains. By adding the mutagenic activity of the three fractions we obtained 20-70% (without $9) and 30-70% ( + $9) of the crude extract activity, suggesting that a proportion of mutagens are lost during fractionation. During air sampling, temperature, atmospheric pressure, light, wind strength and direction, SO 2, CO, NO 2, 0 3 and non-methanic hydrocarbon concentrations were continuously monitored. Meteorological and chemical variables, except total suspended matter, seem not to be correlated significantly with mutagenicity.
123 Bfirta, 1., T. Petr, B. Turek, P. Hrabal, J. Pro~ek and K. Kejlovfi, 3rd Medical Faculty, Charles University and Institute of Hygiene and Epidemiology, Prague (Czechoslovakia) Delayed biological effects of low single doses of aflatoxin B t in vivo
The aim of this work was to compare the time intervals from demonstration of free AFB t in body organs to the appearance of genotoxic damage to cells and the development of manifest carcinogenic changes in vivo in the Chinese hamster ( Cricetulus griseus ). Free AFB t after a single i.p. dose of 0.1 mg AFB~/kg was detected in blood, liver, kidneys and testis within 8-10 h after injection. In subsequent time intervals the concentration of free AFB I was below the detection threshold of the RIA method. Genotoxic effects could be proved by the increasing frequency of chromosomal aberrations in the bone marrow cells detectable from 3 h after AFB l administration. These aberrations tended to persist (depending on the mode of application) up to 60 weeks (in the case of Macaca mulatta monkeys up to 2 years). The minimal effective genotoxic dose was 0.1 ~g A F B l / k g .