• Environmental Mutagens and Carcinogens
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• v.19 no.2
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• pp.108-111
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• 1999

Correlation between the tumorigenic dose (TD) and the maximum tolerated dose (MTD) was examined to search for the most relevant TD values related to the MTD. Using benzo(a)pyrene (B(a)P) 2-yr bioassay data, correlation coefficients between values of $TD_{1-}$50/ and the MTD were estimated from linearized or non-linearlized dose-response curves. The highest correlation coefficients (0.9966-1.0000) were obtained from T $D_{1-}$10/ in linearized dose-response curves while the highest (0.9966-1.0000) were estimated from $TD _{5-}$10/ in non-linearized dose-response eurves. These data suggest that TDs-lo were more closely related to the MTD than the ,$TD_{5-}$10/ in B(a)P 2-yr bioassay and that in lieu of the $TD_{50}$ they could be efficiently applicable to risk assessment and management.ent.

• Environmental Mutagens and Carcinogens
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• v.7 no.2
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• pp.85-102
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• 1987

In spite of high incidences in gastrointestinal cancers in Korea, there have been few studies so far, which tried to detect or isolate the mutagenic, namely the carcinogenic substances in the Korean taste traditional foods. Among the many plausible dietary sources of carcinogens, the pyrolytic products of proteins or amino acids would be the major ones. And it is more noteworthy that the food pattern analysis showed the increasing consumption of protein foods by Korean as pyrolytic products, such as Bulgogi and Kalbi, etc.

• Environmental Mutagens and Carcinogens
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• v.7 no.2
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• pp.103-111
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• 1987

The effects of LET (linear energy transfer) of radiation on the induction of somatic chromosome mutations or gene mutations of Drosophila melanogaster were studied. For detecting somatic chromosome mutations and gene mutations, Drosophila wing spot system and eye-color spot system were used, respectively. The frequencies of somatic chromosome mutations or gene mutations induced after third instar larval treatment with 23 MeV neutrons, thermal neutrons, X-rays were examined. From these data, the RBE(relative biological effectiveness) values of 23 MeV neutrons relative to X-rays for induction of somatic chromosome mutations or gene mutations were calculated. The present results suggest that high LET radiations are efficient than X-ray in producing not only somatic chromosome mutations but also gene mutations.

• Environmental Mutagens and Carcinogens
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• v.26 no.2
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• pp.41-44
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• 2006

This study was peformed to determine the antioxidant, antimicrobial activity and antifungal of the cambodian mushroom, Phellinus linteus, in various concentrations from the mushroom extracts. It's extracts were found to cause significant free radical scavenging effects on DPPH (1,1-diphenyl-2-picrylhydrazyl). This extracts exhibited in vitro broad-spectrum antimicrobial activity of Gram-negative, Gram-positive bacteria and without antifungal activity. On the other hand, the extracts had not significant hemolytic activity against human red blood cells. These results indicate cambodian mushroom, Phellinus inteus having antioxidant and antimicrobial activity without hemolytic activity maybe useful as therapeutic agents.

• Environmental Mutagens and Carcinogens
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• v.15 no.2
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• pp.81-87
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• 1995

The clastogenic activity of capsaicin, a major pungent and irritating constituent of hot chili pepper, was evaluated in cultured human lymphocytes. Capsaicin (125, 250, and 500 $\mu$M) caused cytogenetic damage as determined by increased frequency of chromosome/chromatid aberrations compared to the solvent control. The mitotic indices were also decreased in a concentration-related manner in capsaicin-treated cells. Moreover, capsaicin suppressed [$^3$]thymidine incorporation into lymphocytes. The clastogenicity and cytotoxicity of capsaicin towards human lymphocytes were evident without an external metabolic activation system. Taken together, these findings suggest that capsaicin is a genotoxic agent and may thus represent a potential health hazard in humans.

• Environmental Mutagens and Carcinogens
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• v.15 no.2
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• pp.88-93
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• 1995

Effects of hyperthermia on the induction of DNA single strand breaks and replication inhibition were studied in bleomycin-treated CHO-K$_1$ cells by alkaline elution and alkaline sucrose gradient sedimentation. Bleomycin-induced DNA single strand breaks of DNA were dose-and time-dependently increased, and these strand breaks of DNA were gradually rejoined as post-incubation time passed. Treatment with hyperthermia alone did not affect the induction of DNA single strand breaks. However, pre-exposure of cells to hyperthermia followed by bleomycin treatment greatly increased the single strand breaks, and also reduced the rejoining processes of bleomycin-induced DNA single strand breaks. Bleomycin selectively inhibited the replicon initiation. The combined treatment with hyperthermia and bleomycin markedly potentiated the nonspecific inhibition of replication.

• Environmental Mutagens and Carcinogens
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• v.19 no.1
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• pp.14-19
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• 1999

Chromosome rearrangements induced in human lymphocyte after in vitro exposure to chromium were analysed by the use of fluorescence in situ hybridization(FISH) with triple combination of composite whole chromosome-specific probe for chromosome 1, 2 and 4. Chromosome aberrations was scored by the Protocol for Aberration Identification and Nomenclature Terminology (PAINT). Stable translocation was the most frequent type of aberrations and dicentrics and insertions were also observed. Chromium treatment enhanced the frequencies of stable translocations and color junctions in a dose-dependent manners, but no distinct increase of dicentrics and insertions was seen. The ratio of the yields of translocation to the yields of dicentric varied between 13 to 27. The presents results demonstrate fluorescent in situ hybridization (FISH) is useful for detecting chromosomal rearrangements induced by chromium.

• Environmental Mutagens and Carcinogens
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• v.19 no.1
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• pp.28-33
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• 1999

The SNF2 family includes proteins from a variety of species with roles I cellular processes such as transcriptional regulation, recombination and various types of DNA repair. Several proteins with unknown function are also included in this family. Here, we report the cloning and characterization of hrp 2+ gene (helicase related gene from S. pombe) which was isolated by PCR amplication using the conserved domain of SNF2 motifs within the ERCC6 gene which encodes a protein involved in DNA excision repair. The hrp2+ gene was isolated by screening with yeast S. pombe genomic library. The isolated cloned contained 6.5 kb insert DNA. Southern blot analysis confirmed that S. pombe chromosome contains the same DNA as hrp2+ gene and this gene exists as a single copy in S. pombe genome. The 4.7 kb transcript of mRNA was identified by Northern blot. To examined the transcriptional regulation of hrp2+ gene, DNA damaging agents were treated. These results indicated that the hrp2+ gene may not be directly involved in DNA replication, but may be involved in damage response pathway.

• Environmental Mutagens and Carcinogens
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• v.16 no.1
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• pp.24-29
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• 1996

In this study, the micronucleus test with peripheral blood using acridine orange coated slides was evaluated in mice treated with mitomycin C(MMC) at doses of 0.5, 1.0 and 1.5 mg/kg body weight. The peripheral bloods were obtained at 0, 24, 48 and 72h after treatment. The frequencies of micronucleated reficulocytes(MNRET) in the MMC-treated groups increased dose-dependently, and showed a peak time at 48h after treatment. We also performed the sex differences of MNRET frequency in 0.5 mg/kg MMC treated group, and we observed no sex differences in this experiment. And we evaluated the usefulness of a direct acting clastogen, N-methyl-N-nitrosourea and a indirect acting clastogen, benzo(a) pyrene as the positive control in this supravital micronucleus test. They also caused a significant increase in MNRET frequencies. These results suggest that the supravital staining micronucleus test using MNRET can be useful tool to evalulate the quantitative and qualitative assessment of genotoxicity in vivo compared to classical in vivo micronucleus test using bone-marrow cells.

• Environmental Mutagens and Carcinogens
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• v.16 no.1
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• pp.30-34
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• 1996

This study was performed to examine the availability of using medaka (Oryzias latipes) in teratological test. Medaka embryos were collected within 2 hours post-fertilization and cultured in petri dishes containing buffered saline until hatching. The embryos were treated with 0.56 mg/l chlorpyrifos-methyl and 10 mM methyl methanesulfonate at 20 stages (about 35 hours post-fertilization). Eleven developmental features were selected and observed from 33 stages (about 9 days post-fertilization). Scoring system was developed and applicated for the measurement of potential teratological effects by the test compound. Chlorpyrifos-methyl did not induce teratological effect in medaka embryos. However, we found teratological test using medaka embryo reduced the cost, labors, period and space of experiment significantly compared with teratological study using rodents. Above findings strongly suggest that medaka embryo can be used as a lab animal model for teratogenicity test instead of rodents.