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microsome assay for gaseous chemicals
382 in water containing no peptone is very low, especially when the concentration of NPs is high.
32 Nishikawa, T., H. Kaneta and S. Kusunoki, Life Science Laboratory, Advance Co., Ltd., 1-35, Shimo-ishihara, Chofu, Tokyo 182 (Japan) A study on the cigarette-filter materials capable of adsorbing mutagens in cigarette smoke The aim of this study was to evaluate the abilities of several cigarette-filter materials to adsorb mutagens from cigarette smoke. Each test material was dispersed into fine-cut cellulose acetate fibers, and the mixture was packed into the charcoal filter space between a cellulose acetate filter and a piece of Mild Seven (Japan Tobacco Inc.) cigarette. The test filter cigarette was smoked with an automatic smoking machine. Each cigarette smoke condensate (CSC) was collected on a glass filter and dissolved in dimethyl sulfoxide, and then its mutagenicity was determined by Ames test (TA98, +$9). The reduction rate of total mutagenicity of CSC when using a filter containing a test material to that of control filter was used to assess the filter material's abilities. Crystalline cellulose (particle size: 1-10 /lm) was the most excellent of various materials tested in the present study. Hemin-dyed crystalline cellulose adsorbed mutagens more efficiently than the undyed one. On the other hand, the cellulose acetate filter (0.7 cm × 2.0 cm), in which 5 and 10 mg of hemin-dyed crystalline cellulose were dispersed homogeneously, could reduce the total mutagenicity of CSC by 30 and 50% respectively. Moreover, this filter helped to reduce the specific mutagenicity (revertants/mg of CSC) by 10-20%.
New method in Ames Salmonella/microsome assay for gaseous chemicals The new test procedure using a Tedlar bag for detecting mutagenicity of gaseous chemicals in the Ames Salmonella/microsome assay was developed. The procedure was: 0.1 ml of overnight bacteria culture and 0.5 ml of $9 mix were added to 2 ml top agar containing 50/~M L-histidine and biotin, then overlayed on minimum glucose agar plate. The rack holding inverted plates without lids was placed into a Tedlar bag and exposed to gaseous 1,3-butadiene. (1) The optimum $9 concentration was 100/H/plate under 48 h exposure at 37 ° C. (2) Mutagenicity of 1,3-butadiene was detected by over 14 h exposure, and not detected by 4 h exposure at 37 ° C. (3) The exposure to 1,3-butadiene at 30 °C for 24 h gave better mutagenic response than that at 37 o C. (4) Overlaying bacteria and $9 mix with top agar gave better sensitivity than spreading. (5) The mutagenicity of 1,3-butadiene depended on the amounts of $9 mix in the Tedlar bag: the mutagenicity was of the same magnitude when exposure size was over 4 plates and lower when it was below 2 plates in the Tedlar bag. This method is very useful for the detection of mutagenicity of gaseous chemicals because of its safety, simplicity and inexpensiveness.
34 Nomoto, K., M. Ineyama, M. Murakami, S. Kogiso, A. Yoshitake, J. Miyamoto and T. Kakunaga 1, Takarazuka Research Center, Sumitomo Chemical Co., Takatsukasa, Takarazuka, Hyogo 665, and 1 Research Institute for Microbial Disease, Osaka University, Nakanoshima, Kita-ku, Osaka 530 (Japan) A study on cell transformation assay with B a l b / c 3T3 cells
33 Noguchi, T., A. Araki, F. Takahashi and T. Matsushima a, Japan Industrial Safety and Health Association, Minato-ku, Tokyo 108, and 1 Institute of Medical Science, University of Tokyo, Tokyo 108 (Japan)
Balb/c 3T3 cells (clone A31-1-1) were treated with 3-methylcholanthrene (0.5, 1.0 and 3.0 ~g/ml) for 72 h. After treatment, cells were washed and replated at 4 x 104 cells/6-cm dish and incubated for 3-6 weeks. 4 clones of type III foci were
32 Nishikawa, T., H. Kaneta and S. Kusunoki, Life Science Laboratory, Advance Co., Ltd., 1-35, Shimo-ishihara, Chofu, Tokyo 182 (Japan) A study on the cigarette-filter materials capable of adsorbing mutagens in cigarette smoke The aim of this study was to evaluate the abilities of several cigarette-filter materials to adsorb mutagens from cigarette smoke. Each test material was dispersed into fine-cut cellulose acetate fibers, and the mixture was packed into the charcoal filter space between a cellulose acetate filter and a piece of Mild Seven (Japan Tobacco Inc.) cigarette. The test filter cigarette was smoked with an automatic smoking machine. Each cigarette smoke condensate (CSC) was collected on a glass filter and dissolved in dimethyl sulfoxide, and then its mutagenicity was determined by Ames test (TA98, +$9). The reduction rate of total mutagenicity of CSC when using a filter containing a test material to that of control filter was used to assess the filter material's abilities. Crystalline cellulose (particle size: 1-10 /lm) was the most excellent of various materials tested in the present study. Hemin-dyed crystalline cellulose adsorbed mutagens more efficiently than the undyed one. On the other hand, the cellulose acetate filter (0.7 cm × 2.0 cm), in which 5 and 10 mg of hemin-dyed crystalline cellulose were dispersed homogeneously, could reduce the total mutagenicity of CSC by 30 and 50% respectively. Moreover, this filter helped to reduce the specific mutagenicity (revertants/mg of CSC) by 10-20%.
New method in Ames Salmonella/microsome assay for gaseous chemicals The new test procedure using a Tedlar bag for detecting mutagenicity of gaseous chemicals in the Ames Salmonella/microsome assay was developed. The procedure was: 0.1 ml of overnight bacteria culture and 0.5 ml of $9 mix were added to 2 ml top agar containing 50/~M L-histidine and biotin, then overlayed on minimum glucose agar plate. The rack holding inverted plates without lids was placed into a Tedlar bag and exposed to gaseous 1,3-butadiene. (1) The optimum $9 concentration was 100/H/plate under 48 h exposure at 37 ° C. (2) Mutagenicity of 1,3-butadiene was detected by over 14 h exposure, and not detected by 4 h exposure at 37 ° C. (3) The exposure to 1,3-butadiene at 30 °C for 24 h gave better mutagenic response than that at 37 o C. (4) Overlaying bacteria and $9 mix with top agar gave better sensitivity than spreading. (5) The mutagenicity of 1,3-butadiene depended on the amounts of $9 mix in the Tedlar bag: the mutagenicity was of the same magnitude when exposure size was over 4 plates and lower when it was below 2 plates in the Tedlar bag. This method is very useful for the detection of mutagenicity of gaseous chemicals because of its safety, simplicity and inexpensiveness.
34 Nomoto, K., M. Ineyama, M. Murakami, S. Kogiso, A. Yoshitake, J. Miyamoto and T. Kakunaga 1, Takarazuka Research Center, Sumitomo Chemical Co., Takatsukasa, Takarazuka, Hyogo 665, and 1 Research Institute for Microbial Disease, Osaka University, Nakanoshima, Kita-ku, Osaka 530 (Japan) A study on cell transformation assay with B a l b / c 3T3 cells
33 Noguchi, T., A. Araki, F. Takahashi and T. Matsushima a, Japan Industrial Safety and Health Association, Minato-ku, Tokyo 108, and 1 Institute of Medical Science, University of Tokyo, Tokyo 108 (Japan)
Balb/c 3T3 cells (clone A31-1-1) were treated with 3-methylcholanthrene (0.5, 1.0 and 3.0 ~g/ml) for 72 h. After treatment, cells were washed and replated at 4 x 104 cells/6-cm dish and incubated for 3-6 weeks. 4 clones of type III foci were