• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.217-225
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• 2005

This study was carried out to investigate the genotoxicity in comet and in vitro micronucleus assay and mutagenicity in Ames test of the extracts from leaves and stem of Morus alba L. The samples showed a very weak cytotoxicity on the NIH/3T3 cells by SRB assay. The cell viability of the extracts and fractions from leaves and stems of Morus alba L. was 80% over at $500\;{\mu}g/ml$, and that of the chloroform fractions from leaves and stems showed lower than others. The genotoxicity at $250\;{\mu}g/ml$ of 100% EtOH and water extracts on the NIH/3T3 cells in comet assay was about 40% compared to positive control, and most fractions from 100% EtOH extract of the leaves showed stronger genotoxicity than that offractions from the stem. The genotoxicity with S-9 mix in vitro micronucleus assay of the 100% EtOH and water extracts form Morus alba L. did not indicate any significant difference as compared with control group. The cytokinesis-binucleated cells were showed in the hexan, chloroform, ethylacetate and butanol fractions from the extract of the leaves without S-9, and sample with S-9 showed CB cells in the chloroform fraction from the leaves. In the Ames test, the water and 100% ethanol extracts of Morus alba L. did not have a strong mutagenicity in TA98 and TA100, but the fractions of organic solvents of the ethanol extract had $10{\sim}26%$ of mutagenicity on the TA100 strain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.2
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• pp.232-239
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• 1996

돌연변이 유발 물질인 mitomycin C(MMC)를 처리하여 배양한 Chinese hamster ovary(CHO) cell에 대한 감잎차 추출액의 항돌연변이 효과를 자매 염색 분체 교환(sister chromatid exchange, SCE) 시험법을 사용하여 측정하여 보았다. 감잎차 추출액 자체는 CHO 세포의 SCE 빈도수를 변화시키지 않았으며, 세포의 분열 주기중 S phase에 S9 mixture 없이 감잎차 추출액이 처리되었을 경우 MMC로 유도된 SCE 빈도수를 감소시키지 않았다. 그러나 S9 mixture 존재하에 $G_{1}$ phase에서 MMC 처리 후 감잎차를 처리하는 후처리 방식으로 감잎차 추출액을 처리하였을 때, 저농도($\leq$40$\mu\textrm{g}$/ml)에서 MMC로 인해 유발된 SCE 빈도수가 낮아지는 것을 볼 수 있었다. 이에 비해 고농도(>40$\mu\textrm{g}$/ml)에서는 SCE 빈도수의 감소 효과가 없었다. 본 연구결과, MMC 처리된 CHO 세포에 대한 감잎차 추출액의 항돌연변이 효과를 볼 수 있었고, 이 효과는 S9 mixture 존재하에서 저농도의 감잎차 추출액이 $G_{1}$ phase에 처리되었을 때 나타났다. 감잎차 추출액의 이러한 항돌연변이의 효과의 기전은 감잎차 추출액의 대사산물이 MMC 처리된 CHO 세포에 대한 DNA-excision repair activity를 촉진시키기 때문인 것으로 생각된다.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.107-110
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• 2000

연구목적: 본 연구는 자궁내막증과 무월경 불임환자들을 대상으로 $LH{\beta}$ exon 2 유전자의 돌연변이를 탐색하고자 시도하였다. 연구재료 및 방법: 그 대상으로 22명의 자궁내막증 환자와 12명의 무월경 환자 그리고, 54명의 건강한 비임신 여성을 대조군으로 사용하였다. 이들을 대상으로 한 돌연변이 탐색은 PCR-RFLP(polymerase chain reaction-restriction fragment polymorphism) 방법으로 수행되었다. 결과: 그 결과 자궁내막증과 무월경증 환자에서 그 변이의 비율이 각각 18.2%, 16.7% 그리고, 대조군에서 역시 16.7%의 빈도를 나타냈다. 결론: 따라서, 자궁내막증과 무월경증 환자는 $LH{\beta}$ exon 2 돌연변이와는 서로 관련이 없거나 매우 적음을 알 수 있었다.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.21-26
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• 1999

To investigate the combined effect of radiation and pesticide on Tradescantia somatic cell mutations, potted plants of Tradescantia 4430 on which parathion had been sprayed evenly 24 hours before irradiation. Radiation doses were 0.3, 0.5, 1.0 and 2.0 Gy of gamma-ray. The plants irradiated only with the gamma-ray radiation were used as control groups (CT). Pink mutation frequency increased linearly proportional to the radiation dose and the peak interval of elevated mutation frequencies appeared during 7 ~ 11 days after irradiation in both CT and Pa +${\gamma}$ groups. The slope of dose -response curve in CT was 5.99 ($r^2$= 0.988), while it was 3.43 (r$x^-2$=0.981) in Pa+${\gamma}$. It seemed that parathion pretreatment had a protective effect against radiation-induced cell damages since it decreased the slope value by 43%. It is suggested that an adaptive response or radiomodification could be induced in irradiated stamen hair cells by parathion pretreatment.

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.299-304
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• 1986

The cell volume, cell surface, cell concentration, dry cell weight, frequence of respiratory deficient mutation, resistance against ultraviolet irradiation, fermentation power, DNA contents of haploid diploid, triploid and tetraploid of Saccharomyces cerevisiae strain were investigated. Respiratory deficient mutants by spontaneous mutation were absolved more frequently in the haploid than in the diploid, triploid and tetraploid. And cell volume, cell surface, cell concentration, dry cell weight, resistance against ultraviolet irradiation, fermentation power, and DNA contents were significantly increased as the ploidy increased.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.395-403
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• 1993

Background: The cell cycle is composed of a series of steps which can be negatively or positively regulated by various factors. Alteration or inactivation of p53 by mutations, or by its interactions with oncogene products of DNA tumor viruses, can lead to cancer. Mutations of the p53 gene occur frequently in human primary lung cancers and the wild-type p 53 allele is often concomitantly deleted. These suggest that deprivation of suppressive role of the wild-type p53 may ensure tumor cell growth presumable by the mutant p53 gene. Methods: In an attempt to investigate this hypothesis, a mutant p53 gene was immunohistochemically demonstrated in the formalin-fixed paraffin-embedded tissue sections of lung cancers by using a monoclonal antibody p53 (Ab-3 and clone DO7). Results: The expression of p53 (DO7) was found in all four normal lung tissues, four small cell carcinomas, and four non small cell carcinomas in histologic types of lung cancer. In the six normal lung tissues the expressions of p53 (Ab-3) were not found. Contrarily, the expression of p53 (Ab-3) was found in the nuclei of lung cancers among fifteen (46.9%) of thirty-two cases studied. The expression of p53 (Ab-3) was disclosed in three case (37.5%) of eight small cell carcinomas and twelve cases (50.0%) of twenty-four non small cell carcinomas in histologic types of lung cancer. Conclusion: These findings suggest that expression of the mutant p53 is related to the one of events in the pathogenesis of human lung cancer and the role of the other oncogenes might be also related to the development of lung cancers.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.546-557
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• 2000

Background : Oligonucleotide chip technology has proven to be a very useful tool in the rapid diagnosis of infectious disease. Rifampin resistance is considered as a useful marker of multidrug-resistance in tuberculosis. Mutations in the rpoB gene coding $\beta$ subunit of RNA polymerase represent the main mechanism of rifampin resistance. The purpose of this study was to develop a diagnosis kit using oligonucleotide chip for the rapid and accurate detection of rifampin-resistance in Mycobacterium tuberculosis. Method : The sequence specific probes for mutations in the rpoB gene were designed and spotted onto the glass slide, oligonucleotide chip. 38 clinical isolates of Mycobacterium were tested. A part of rpoB was amplified, labelled, and hybridized on the oligonucleotide chip with probes. Results were analyzed with a laser scanner. Direct sequencing was done to verify the results. Result : The low-density oligonucleotide chip design어 to determine the specific mutations in the rpoB gene of M. tuberculosis accurately detected rifampin resistance associated with mutations in 28 clinical isolates. Mutations at codons 531, 526, and 513 were confirmed by direct sequencing analysis. Conclusion : Mutant detection using oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of multidrug-resistance in M. tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.48 no.6
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• pp.853-869
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• 2000

Background : Following several decades of decline, the incidence of tuberculosis has recent1y begun to increase in many countries of this the control of this disease has been impeded by the emergence of multi-drug resistant tuberculosis (MDR-TB). The development of rapid diagnostic methods and effective new drugs are needed to control MDR-TB. One of the new drugs for MDR-TB is rifabutin (RBU) which has been known to be effective in some patients with MDR-TB. A few reports showed that some types of mutations of the rpoB gene, which were known to be present in 96-98% of rifampicin-resistant M. tuberculosis, were associated with the rifampicin-resistant but RBU-susceptible phenotype. This study was performed to investigate the correlation between RBU susceptibility and the patterns of rpoB gene mutations in Korean MDR-TB. Methods : Sixty-five clinical isolates of multi-drug resistant Mycobacterium tuberculosis, gathered from patients who visited the Asan Medical Center from July 1997 to June 1999, were investigated. Clinical responses to rifabutin-containing regimen were evaluated. An RBU susceptibility test and sequencing analysis of rpoB gene were performed, and the results were analyzed to confirm which mutations correlated with RBU-susceptible MDR-TB. Results : Fifty-three of 56 (95%) clinical isolates of MDR-TB had 60 mutations of the rpoB gene. The most frequent mutations were found at codon 531 (43%), and two mutations were combined in seven clinical isolates. Five of 53 (10%) clinical isolates showed the RBU-susceptible phenotype, and in them the characteristic patterns of point mutations were found at codon 509, 516, and 526. Conclusion : The frequency and pattern of mutations of the rpoB gene of Korean MDR-TB isolates were similar to those in western countries, where the prevalence of tuberculosis is low, but some show RBU-susceptible phenotypes. RBU-susceptible MDR-TB isolates showed the characteristic pattern of mutations of the rpoB gene which could be used to rapidly diagnose RBU susceptibility.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.196-202
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• 2006

Treatment of hepatitis B virus (HBV) with lamivudine is effective in suppressing virus replication and results in reduced inflammatory activity. However the most troublesome problem of lamivudine treatment is the emergence of lamivudine-resistant strains with amino acid substitution in the YMDD motif of DNA polymerase gene during the treatment. The aim of this study was to determine the mutation of YMDD motif (codon 552) and codon 528 in chronic HBV patients with lamivudine therapy using PCR-direct sequencing and to investigate the relationship between lamivudine mediated HBV mutation and HBeAg. HBV DNA was extracted from serum samples of HBV patients and amplified by nested PCR with two sets of primer pairs selected in HBV DNA polymerase gene. Amplified PCR product was analyzed by 2% agarose gel electrophoresis and direct sequencing. HBV mutation was detected in 124 out of 207 samples (60%). Single mutation was 50.8% for M552I, 43.5% for M552V, 5.7% for M552I/V and the L528M mutation was 67.0%. Double mutation was 43.6% for M552V/L528M, 33.1% for M552I/L528(wild type), 17.7% for M552I/L528M and 5.6% for M552I/V/L528M. Serine mutation at YMDD motif (M552S) was not found and the L528M mutation frequently accompanied M552V type. In this study, the typical difference of frequencies for HBV mutation depending on HBeAg was not found. Moreover, the PCR-direct sequencing method used in this study might be a powerful tool for the mutation study in clinical reference laboratories with high volume.

• Environmental Mutagens and Carcinogens
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• v.18 no.2
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• pp.109-115
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• 1998

Fluorscence in situ hybridization with chromosome-specific probe has been shown to be a valid and rapid method for detection of chromosome rearrangements induced by chemical and physical agents. This method is useful for quantifying structural aberrations, expecially for stable ones, such as translocation and insertion, which are difficult to detect with conventional method in human lymphocyte. In order to use the FISH method as a biodosimeter for monitoring human population exposed to various chemical and physical agent, baseline level of chromosome rearragement was established. Blood from forty four healthy adults were collected and analysed with whole chromosome-specific probes by human chromosome 1,2 and 4. The frequencies of stable translocation were 2.45 per 100 cell equivalent and those of insertion, color juction, acentric and dicentric were 0.32, 3.28, 0.23 and 0.27 per 100 cell equivalent respectively. The frequencies of chromosome rearragements increased with age in both sexes except for dicenrics. From above result, stable aberrations accumulate with age and it may reflect integrated lifetime exposure of adverse environment.