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Chromosome observation of mouse intestinal epithelial cells
101 Changes of 5-FU levels in plasma and in bone marrow were examined to clarify the accumulating effects and the delay in appearance of M N in cells. 5-FU in both samples increased promptly after i.p. injection, and it disappeared from the plasma within 1 h. In the bone marrow it decreased more slowly than in the plasma. Accumulation of 5-FU in both samples was not observed. Therefore, the delayed appearance of M N could not be explained by the level of 5-FU, and is thought to be due to other factors, such as an inhibition of the cell cycle. The accumulative effect of 5-FU in the M N test is thought to be due to additive effects of various incidences of M N in cells.
45 Ohyama, W., and T. Tokumitsu, Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi-Shi, Tokyo 186 (Japan)
Chromosome observation of mouse intestinal epithelial cells We have devised a method to observe chromosomes of cryptic epithelial cells of mouse intestine. A 4-cm piece of intestine or half of a cecum was dissected from a mouse to which colchicine was administrated 1 h prior to sacrifice and vibrated to facilitate release of cells every 10 min during and after incubation in a solution of 1 m M E D T A for 30 rain at 30 o C. Cells were collected by centrifugation and were treated hypotonically at 3 0 ° C and then fixed serially with a mixture of methanol and acetic acid ( 3 : 2 ) and with a 60% diluted solution of this mixture. The mixture was replaced with an undiluted one and a few drops of the cell suspension were placed on a slide. With this method, chromosomes were well spread in more than 100 cells from the 4 cm of intestine. In colonic cells of mice which had received M N N G through the anus, chromosome aberrations were detected up to 10% at 12 h after administration. Chromosome aberrations were observed, however, in 0-2.3% of the cells from various parts of untreated mouse intestine. We are now studying a method to observe chromosomes of the glandular stomach.
46 Okada, M. ~, S. N a k a m u r a 2, K. Miura 3 and K. Morimoto 3, ~ School of Medicine, Osaka University, Osaka, 2 Department of Industrial Health, Osaka Prefectural Institute of Public Health, Osaka and 3 Department of Hygiene and Preventive Medicine, School of Medicine, Osaka University, Osaka (Japan)
The antimutagenic effects of human saliva investigated with the umu-test. I. Effects of filtration and storage at low temperatures The antimutagenic effects of human saliva were examined with the umu-test. The SOS-inducible D N A - d a m a g i n g activity of AF-2 was markedly decreased by pretreatment with fresh human saliva. The antimutagenic activity of human saliva was retained even after filtration (0.45 t~m). This activity was also observed after 24-h storage at 1 0 ° C or - 1 2 ° C . These results are consistent with previous reports using the Ames test. Significant differences in activity, however, were observed among donors and among experiments with samples from the same donor. Further analyses of the effects of the factors contained in saliva as well as the effects of donor lifestyle, including dietary habits, will be necessary.
47 Okamoto, A. ~, K. Kuroda 1, G. Endo 2 and S. Horiguchi 2, ~ Osaka City Institute of Public Health and Environmental Sciences, 8-34, Tojohcho, Tennoji-ku, Osaka 543 and 2 Department of Preventive Medicine and Environmental Health, Osaka City University Medical School, 1-4-54, Asahi-machi, Abenoku, Osaka 545 (Japan)
Study on the mutagenicity of quercetin The mutagenicity of quercetin is affected by exogenous factors (active oxygen, etc.). The mechanism of its mutagenicity is not known. Therefore we have examined the effects of some exogenous factors including arsenic compounds (asozin, ptolylarsonic acid), superoxide dismutase (SOD) and metallothionein on the mutagenicity of quercetin. It is said that metallothionein acts like SOD. In the presence of SOD the mutagenic activity of quercetin was enhanced and a change of
45 Ohyama, W., and T. Tokumitsu, Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi-Shi, Tokyo 186 (Japan)
Chromosome observation of mouse intestinal epithelial cells We have devised a method to observe chromosomes of cryptic epithelial cells of mouse intestine. A 4-cm piece of intestine or half of a cecum was dissected from a mouse to which colchicine was administrated 1 h prior to sacrifice and vibrated to facilitate release of cells every 10 min during and after incubation in a solution of 1 m M E D T A for 30 rain at 30 o C. Cells were collected by centrifugation and were treated hypotonically at 3 0 ° C and then fixed serially with a mixture of methanol and acetic acid ( 3 : 2 ) and with a 60% diluted solution of this mixture. The mixture was replaced with an undiluted one and a few drops of the cell suspension were placed on a slide. With this method, chromosomes were well spread in more than 100 cells from the 4 cm of intestine. In colonic cells of mice which had received M N N G through the anus, chromosome aberrations were detected up to 10% at 12 h after administration. Chromosome aberrations were observed, however, in 0-2.3% of the cells from various parts of untreated mouse intestine. We are now studying a method to observe chromosomes of the glandular stomach.
46 Okada, M. ~, S. N a k a m u r a 2, K. Miura 3 and K. Morimoto 3, ~ School of Medicine, Osaka University, Osaka, 2 Department of Industrial Health, Osaka Prefectural Institute of Public Health, Osaka and 3 Department of Hygiene and Preventive Medicine, School of Medicine, Osaka University, Osaka (Japan)
The antimutagenic effects of human saliva investigated with the umu-test. I. Effects of filtration and storage at low temperatures The antimutagenic effects of human saliva were examined with the umu-test. The SOS-inducible D N A - d a m a g i n g activity of AF-2 was markedly decreased by pretreatment with fresh human saliva. The antimutagenic activity of human saliva was retained even after filtration (0.45 t~m). This activity was also observed after 24-h storage at 1 0 ° C or - 1 2 ° C . These results are consistent with previous reports using the Ames test. Significant differences in activity, however, were observed among donors and among experiments with samples from the same donor. Further analyses of the effects of the factors contained in saliva as well as the effects of donor lifestyle, including dietary habits, will be necessary.
47 Okamoto, A. ~, K. Kuroda 1, G. Endo 2 and S. Horiguchi 2, ~ Osaka City Institute of Public Health and Environmental Sciences, 8-34, Tojohcho, Tennoji-ku, Osaka 543 and 2 Department of Preventive Medicine and Environmental Health, Osaka City University Medical School, 1-4-54, Asahi-machi, Abenoku, Osaka 545 (Japan)
Study on the mutagenicity of quercetin The mutagenicity of quercetin is affected by exogenous factors (active oxygen, etc.). The mechanism of its mutagenicity is not known. Therefore we have examined the effects of some exogenous factors including arsenic compounds (asozin, ptolylarsonic acid), superoxide dismutase (SOD) and metallothionein on the mutagenicity of quercetin. It is said that metallothionein acts like SOD. In the presence of SOD the mutagenic activity of quercetin was enhanced and a change of