• Journal of Magnetics
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• 제8권1호
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• pp.1-6
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• 2003

The new class of $Gd_5(Si_xGe_{1-x})_4$ compounds undergoes a simultaneous magnetic/structural phase transition giving a high level of strain that can be induced either by change in temperature or by application of a magnetic field. Profound changes of structural, magnetic, and electronic changes occur in the $Gd_5(Si_xGe_{1-x})_4$ system lead to extreme behavior of the material such as the giant magnetocaloric effect, colossal magnetostriction, and giant magnetoresistance. These unique material characters can be utilized for various applications including magnetic solid refrigerants, sensors, and actuators.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
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• pp.171-171
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• 1993

발암물질의 조기검색법을 개발하고자 변이원성 물질의 스크리닝법으로 널리 사용되고 있는 Ames test 및 chromosomal aberration test를 본 연구에서 개발하고자 하는 DNA 및 Protein-adduct 형성시험법과 비교 연구하였다. 벤조피렌과 아플라톡신 B$_1$을 모델 발암물질로 하여 실시한 Ames test에서는 두 화합물 모두 양성을 나타냈으나 용량-반응 관계가 뚜렷하지 않았다. 또한 고농도에서는 시험물질의 독성체 의해 정상적인 Ames test의 수행이 어려됐다. Chromosomal aberration test에서도 Ames test와 비슷한 결과를 나타냈으며 특히 고농도에서 시험을 실시했을 경우 Ames test에서와 마찬가지로 세포독성의 현상이 관찰되었다. 그러나 본 연구에서 새로이 개발한 DNA 및 Protein-adduct형성 시험법은 저농도에서 고농도에 이르기까지 뚜렷한 용량-반응 관계를 나타냈으며 Ames test 및 chromosomal test에서 일어날 수 있는 false positive나 false negative의 결과를 가져다 줄 우려가 없다. 또한 시험시간이 1-2시간 정도 소요되므로 기존의 방법보다 시험시간을 약 40배 가량 단축시킬 수 있었다.

• 생명과학회지
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• 제5권3호
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• pp.121-125
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• 1995

To determine whether the omega 3 family, linolenic acis(LnA) is effective to inhibit carcinogens/mutagens-induced mutagenesis, we employed the Ames test using Salmonella typhimurium strain of TA100 and the SOS chromotest using Escherichia coli PQ37 strain. The inhibitory effect of LnA shown in the Ames assaying system was 95%, 78% and 73% when the mutagenicities were mediated by AFB$_{1}$, MNNG and 4-NQO, respectively. LnA shows a strong antimutagenic activity against indirect mutagen of AFB$_{1}$, whereas the same concentration of LnA exhibited weaker inhibitory effects on the direct mutagen of MNNG and 4-NQO than that of AFB$_{1}$. However. LnA reduced more than 80% of SOS responses induced by MNNG and 4-NQO when the adding concentration increased to 5%. We conclude that LnA contains in vitro antimutagenic properties and that this finding warrants further investigation both in vitro and in vivo to assess its possible chemotherapeutic potential.

• 한국환경성돌연변이발암원학회지
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• 제25권1호
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• pp.6-12
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• 2005

Many compounds might become activated after absorption of UV light energy. In some cases, the resulting molecule may undergo further biological reaction of toxicological relevance related especially to the photo-carcinogenicity resulting from photo-genotoxicity. However, no regulatory requirements have been issued with the exception of guideline issued by the Scientific Committee of Cosmetology, Commission of the European Communities (SCC/EEC) on the testing of sunscreens for their photo-genotoxicity. Thus, the objectives of this study are to investigate the utility of photo-Ames assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-Ames assay was performed on five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an a-adr-energic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and retinoic acid (a retinoid compound closely related to vitamin A). Out of 5 test substances, 3 showed a positive outcome in photo-Ames assay. With this limited data set, an investigation into the predictive value of this photo-Ames test for determining the photo-carcinogenicity showed that photo-Ames assay has relatively low sensitivity (the ability of a test to predict carcinogenicity). Thus, to determine the use of in vitro genotoxicity tests for prediction of carcinogenicity,' several standard photo-genotoxicity assays should be compared for their suitability in detecting photo-genotoxic compounds.

• 생약학회지
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• 제34권1호통권132호
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• pp.80-85
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• 2003

Water extract from Astragali Radix (AR) was tested for the safety using Ames, Bacillus subtilis Rec, and umu gene expression mutagenicity tests. Mutagenic activity in any assays we tested was not found. In Ames test, Salmonella typhimurium TA98 and TA 100 were used to identify mutagenic property, and the number of histidine revertants was measured. In the Recassay, Bacillus subtilis ${H-17(Rec^+)\;and\;M-45(Rec^-)}$ strains were used to test DNA damage activity. In the SOS umu test, Salmonella typhimurium TA1535 containing plasmid pSK1002 was used as a test strain, and we monitored the levels of umu operon expression by measuring the ${\beta}-galactosidase$ activity. From the results, there was no DNA damage and mutagenicity of AR. Hepatotoxicity of AR to female ICR mice was also monitored by the measurements of s-GOT, s-GPT, LDH activities after oral feeding for 15 days. AR was not shown any significant changes of s-GOT, s-GPT and LDH activities in mice sera.

• Preventive Nutrition and Food Science
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• 제4권1호
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• pp.38-42
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• 1999

Antimutagenic effects of 5 kinds of kochujang(Korean red pepper soybean paste) samples compared with doenjang(Korean soy paste) were studied using the Ames test with Salmonella typhimurium TA100 and the SOS chromotest, with E. Coli PQ37. Th eantimutatenic effects of methanol extracts from red pepper powder and meju(fermented soybean) powder, the major ingredients of the kochujang,were also evaluated for the mutagenicity of aflatoxin B1 (AFB1) in the Ames assay. The methanol extracts from the kochujang samples showed lower antimutagenicities than those of doenjang against AFB1 and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in the Ames assay. Traditional kochujang I and II exhibited strong antimutagenic activity against AFB1 and MNNG. The traditional kochujang samples against MNNG were aslo observed in the SOS chromotest system with the same fashions as shown in the Ames mutagenicity test. The methanol extracts from meju powder had the strongest inhibitory effects on mutabenicity induced by AFB1, however, those form red pepper powder showed lower inhibition rate than kochujang. These results suggest that traditional kochujang exhibit higher antimutagenic acitivity than the commercial variety, and that meju powder seems to be one of the major antimutagenic components in kochujang.

• 한국미생물·생명공학회지
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• 제20권5호
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• pp.498-504
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• 1992

고구마효소 갈변반응생성물(SPEBRP)의 항돌연변이 효과를 검토하기 위하여 DNA breaking test, spore rec assay, Ames test를 행하였다. DNA breaking test에서 catechol- 및 hydroxyhydroquinone-SPEB-RPs는 $Fe^{2+}$ 존재하에서 DNA breaking effect를 저해하였다. Bacillus subtilis H17(rec+) 및 M45(rec-)를 이용한 spore rec assay엣 3,4-dihydroxytoluene-SPEBRP는 MNNG에 대하여 강한 돌연변이 효과를 나타내었다. Salmonella typhimurium TA98 및 TA 100를 이용한 Ames test에서 pyrogallol-, 3,4-dihyd-roxytoluene-, hydroxyhydroquinone-SPEBRPs 들은 발암물질인 Benzo($\alpha$)Pyrene에 대하여 67.71, 63%의 강한 활성억제를 나타내었다.

• 한국환경성돌연변이발암원학회지
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• 제20권1호
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• pp.21-25
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• 2000

Recently there is increasing interest in the use of structure activity relationships for predicting the biological activity of chemicals. The reasons for the interest include the decrease cost and time per chemical as compared with animal or cell system for identifying toxicological effects of chemicals and the reduction in the use of animals for toxicological testing. This study is to test the validity of the mutagenicity data generated from QSAR (Quantitative Structure Activity Relationship) program. Thirty chemicals, which had been evaluated by Ames test during 1997-1999, were assessed with TOPKAT QSAR mutagenicity prediction module. Among 30chemicals experimented, 28 were negative and 2 were positive for Ames test. On the contrary, 23 chemicals showed the high confidence level indicating high prediction rate in mutagenicity evaluation, and 7 chemicals showed the lsow to moderate confidence level indicating low prediction in mutagenicity evaluation. Overall mutagenicity prediction rate was 77% (23/30). The prediction rates for non-mutagenic chemicals were 79% (22/28) and mutagenic chemicals were 50% (1/2). QSAR could be a useful tool in providing toxicological data for newly introduced chemicals or in furnishing data for MSDS or in determining the dose in toxicity testing for chemicals with no known toxicological data.

• 한국식품위생안전성학회지
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• 제11권1호
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• pp.17-24
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• 1996

The genotoxicity of combinations of four p-oxybenzoic acids (methyl paraben, ethyl paraben, isopropyl paraben, butyl paraben) and benzoic acid had been evaluated. The in vitro Ames test using Salmonella typhimurium (TA 98, TA 100, 1535, TA 1537) and the invivo micronucleus assay using mouse peripheral blood were performed. Methyl paraben plus benzoic acid, ethyl paraben plus benzoic acid, and ethl paraben plus butyl paraben slightly increased the frequency of microuncleated reticulocytes in the high doses, but were negative in Ames test with Salmonella typhimurium with and without rat liver microsomal activation. The other combinations tested were negative in Ames test and did not show any clastogenic effect in micronucleus test. These results suggest that genotoxicity can produced by th combination of p-oxybenzoic acid.

• 한국식품영양과학회지
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• 제33권6호
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• pp.930-935
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• 2004

Ames test와 SOS chromotest를 이용하여 유기 게르마늄과 게르마늄을 첨가하여 재배한 콩나물의 항돌연변이 효과를 검토하였다. 균주 Salmonella typhimurium TA100에서 AFB$_1$에 의하여 유발된 돌연변이는 Ge-132와 게르마늄 가루에 의하여 농도 의존적으로 저해 효과가 높게 나타났으며, 특히 유기 게르마늄을 20 mg/plate 첨가하였을 때 대조군에 비하여 87%의 돌연변이 유발 억제율을 나타내었다. 똑같은 실험계에서 게르마늄을 첨가하여 재배한 콩나물의 즙액과 methanol 추출물은 수돗물로 재배한 콩나물에 비하여 돌연변이 유발억제 작용이 유의적으로 높게 나타났다. 또한 직접돌연변이원인 MNNG와 4-NQO에 의해 유발된 돌연변이는 일반콩나물의 즙액을 200 $\mu$L/plate 첨가하였을 때 각각 37∼39%, 38∼48%의 저해효과를 나타낸 반면 같은 농도에서 게르마늄 콩나물의 즙액은 61%와 75%의 억제율을 나타내어 게르마늄 첨가 콩나물은 간접 돌연변이원뿐만 아니라 직접 돌연변이원에 의해서 유발된 돌연변이도 억제함을 알 수 있었다. 한편 E. coli PQ37 균주를 사용한 SOS chromotest에서 유기 게르마늄은 사용된 농도의 증가에 따라 돌연변이 유발억제작용이 증가하였으며, 게르마늄 콩나물의 methanol 추출물은 일반 콩나물에 비하여 높은 돌연변이 유발 억제작용을 나타내었다. 따라서 Ames test와 SOS chromotest를 통하여 게르마늄을 첨가하여 재배한 콩나물은 수돗물로 재배한 콩나물에 비하여 항돌연변이 효과가 우수한 것을 알 수 있었다.