• 한국환경성돌연변이발암원학회지
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• 제7권2호
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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.

• 환경생물
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• 제24권2호
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• pp.155-159
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• 2006

To reveal effects of gamma-irradiation with various doses on the expressions of C4H and F5H genes, the transcription levels of OsC4HL and OsF5HL were investigated in leaves and stems of two rice cultivars, Ilpoombyeo and IR-29, after the irradiation with 5, 10, 50, or 100 Gy for 4 h. In overall pattern of 24 h after the irradiation, the transcription levels of the two genes increased with the increasing doses of radiation in the leaves of both cultivars, except that of OsC4HL in IR-29. However, in the stems, the transcription level of OsF5HL increased in Ilpoombyeo and decreased in IR-29 dose-dependently, while that of OsC4HL decreased in Ilpoombyeo with the increasing doses of radiation and remained constant in IR-29. When the expressions of OsC4HL and OsF5HL were investigated in a time-course after the irradiation with 100 Gy, they reached their highest levels in the leaves of both cultivars 5 hand 72 h after the irradiation, respectively. Therefore, we suggest that the expressions of OsC4HL and OsF5HL, which involved in the same phenylpropanoid pathway, are differentially regulated during the post-irradiation period, showing different cultivar and tissue specificity. Furthermore, the dose dependency of the gene expressions is also discussed immediately after the irradiation.

• 환경생물
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• 제27권2호
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• pp.140-145
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• 2009

All organisms are being exposed to harmful factors present in the environmental. The combined action of various factors is a distinguishing feature of modern life. An interaction between two chemicals is considered as synergistic when the effect produced is greater than the sum of the two single responses. The biological effects due to the combined action of ionizing radiation with the other factor are hard to estimate and predict in advance. In the current study, we investigated the synergistic effects between ionizing and $HgCl_2$ using fish hepatoma cells (PLHC-1 cells). The results showed a dramatic decrease of cell viability after simultaneous treatment of PLHC-1 cells with ionizing radiation and $HgCl_2$. Neiither of the two had any cytotoxic effect when treated alone. The cytotoxicity of ionizing radiation was enhanced in the presence of $HgCl_2$. The synergistic effects were observed after exposure of the PLHC-1 cells to ionizing radiation combined with $HgCl_2$. The synergistic interaction was due to an increase of irreversibly damaged cells after the combined exposure. Analysis of the extent of synergistic interaction enables to make quantitative estimation of irreversibly damaged cells after the combined exposure. The present study suggests that PLHC-1 cells can serve as rapid screening tools for detecting the toxicity of harmful factors.

• 한국동물학회:뉴스레터
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• 제16권1호
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• pp.56-59
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• 1999

• International Journal of Industrial Entomology and Biomaterials
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• 제47권2호
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• pp.90-98
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• 2023

The human eye, constantly exposed to solar radiation, can be damaged by UV radiation. In particular, ultraviolet B (UVB)-induced damage plays an important role in retinal degeneration and cell aging. In this study, we investigated the protective effects of the methanol extract of Oxya chinensis sinuosa (OCM), an edible insect known for its high protein content (64.2%), and various pharmacological effects, on human retinal pigment epithelial cells. ARPE-19 cells were treated with OCM and subsequently UVB irradiated. Our results showed that OCM effectively attenuates UVB-induced cell damage by reducing MAPK phosphorylation (JNK and p38 MAPK). Additionally, OCM increased the phosphorylation of Akt, and cell cycle regulators, including p21 and p27, in a dose-dependent manner. Moreover, OCM treatment increased ARPE-19 cell proliferation by activating the S6K1/S6 pathway. This study suggests that OCM prevents UVB-induced retinal cell damage by increasing cell proliferation via ROS reduction, suggesting its potential as a functional therapeutic superfood against retinal cell damage.

• 환경생물
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• 제23권2호
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• pp.152-156
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• 2005

Ionizing radiation is a well- known therapy factor for human carcinoma cells. Genotoxic stress mediates cell cycle control, transcription and cellular signaling. In this work, we have used a microarray hybridization approach to characterize the cell type-specific transcriptional response of human carcinoma MCF-7 and HeLa cell line to $\gamma-radiation$, such as 4Gy 4hr. We found that exposure to $\gamma-ray$ alters by at least a $log_2$ factor of 1.0 the expression of known genes. Of the 27 genes affected by irradiation, 11 are down- regulated in MCF-7 cells and 2 genes induced by radiation,15 are repressed in HeLa cells. Many genes were involved in known damage- response pathways for cell cycling, transcription factor and cellular signaling response. However, in MCF-7 cells, we observed gene expression pattern in chromatin, apoptosis, stress, differentiation, cytokine, metabolism, ribosome and calcium. In HeLa cells, it showed clearly the expression changes in adhesion and migration, lysosome, brain, genome instability and translation. These insights reveal new therapy directions for studying the human carcinoma cell response to radiation.

• 환경생물
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• 제21권4호
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• pp.368-376
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• 2003

The UV-B sensitivity was tested for the intertidal species Chondrus ocellatus from Korea, by measuring photosynthesis estimated as effective quantum yield ($\Phi_{PSII}$) of photosystem II (PS II), growth and content and composition of photosynthetic pigments and UV-absorbing pigments (UVAPs). The $$\Phi_{PSII}$ of the alga decreased with increasing time of exposure to UV-B radiation, followed by fast and nearly full recovery indicating dynamic photoinhibiton. Fresh weight-based growth and pigment contents of C. ocellatus were not seriously affected by UV-B radiation. A single broad peak at 327 nm was obtained from methanol extracts of C. ocellatus, and the absorbance peak increased with increasing UV. The single peak was resolved into three peaks (311, 330 and 336 nm) by the fourth -derivative, and quantitative change in response to UV-B radiation occurred only at 330 nm. High performance liquid chromatography (HPLC) analysis of purified extracts indicated that three MAAs (mycosporine-like amino acids) are present, asterina 330, palythine and shinorine. Field observations during three growing months showed that C. ocellatus exhibit the highest amount of UVAPs in May followed by July and little trace in September, coinciding with the species' phenology. In an ecological context, dynamic photoinhibition as well as accumulation of UVAPs may enable the shallow water red alga C. ocellatus to be well adapted to high UV-B environments.

• Clinical and Experimental Reproductive Medicine
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• 제21권3호
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• pp.297-303
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• 1994

The effect of radiation on the steroidogenesis of rat ovary was investigated. For this purpose, female rats aged 7-8 weeks were exposed to a single dose of ${\gamma}$ radiation(320 rad or 800 rad) by the cobalt-60. At fourth(day of the first estrus) and eighth(day of the second estrus) days after irradiation, the concentrations of serum steroid hormones were determined by radioimmunoassays (RIA). The correlation between survival rate(Y) and radiation dose(X) was Y=-0.06X+100(r=0.89, n=10). Lethal dose$(LD)_{50(30)}$ and $LD_{20(30)}$ were 833.33rad and 333.33rad respectively. The weights of body and ovary was decreased significantly by the $LD_{50(30)}$ irradiation during the 4 days, but both weights were recovered at day 8. The serum levels of 17a-hydroxyprogesterone(170HP) and estradiol($E_2$) in the irradiated rats were not generally different from those of control. However, the levels of testosterone(T) and 19-norterstosterone(19NT) in the irradiated rat at $LD_{50(30)}$ and $LD_{20(30)}$ radiation doses were decreased, while progesterone levels in serum of the irradiated rats were slightly increased. These results suggest that irradiation may inhibit the first step of steroidogenesis, especially the conversion of P to T, in the rat ovary.

• Radiation Oncology Journal
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• 제30권1호
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• pp.14-19
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• 2012

Purpose: We collected the data of Science Citation Index (SCI) and SCI Expended (SCIE) papers written by the members of the Korean Society of Radiation Oncology (KOSRO) to analyze the current status and the future trend. Materials and Methods: We searched the database of SCIE for the period from 1981 to 2011 at the Web of Knowledge site. Articles, reviews or proceedings written by KOSRO members as the first or corresponding authors were included. Search terms were the following combination of subject headings: therapeut radiol, radiat oncol, Korea. For National Cancer Center, combined search terms such as natl canc ctr, Korea and the names of faculties were applied. Results: The total number of SCIE papers was 547. Numbers of the published papers in 1995, 2000, 2005, and 2010, were increased continuously, which was 2, 14, 40, and 83, respectively. The average impact factor was 2.9. The papers were published at the 134 different journals. The proportion of "International Journal of Radiation Oncology Biology Physics" was 23.4% of all the papers. The number and proportions of papers by subject categories were 87 (15.9%) in biology, 73 (13.3%) in physics and 387 (70.6%) in clinics. The papers of the top five institutions, based on the number of published papers, occupied 66.3%. Conclusion: The number of SCIE papers is increasing rapidly in the field of radiation oncology in Korea. To improve the quality of papers, multi-institutional retrospective or prospective randomized studies should be done for the common cancers in Korea.

• 환경생물
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• 제22권3호
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• pp.472-477
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• 2004

본 연구에서는 감마선으로 유도된 돌연변이체들에서 공통으로 발현되는 방사선 관련 유전자들의 발현을 연구하기 위하여, B. lentimorbus WJ5 의 방사선 유도 돌연변이체에서 발현되는 유전자를 DNA microarray로 동시에 탐색하였다. DNA microarray는 B. lentimorbus WJ5 genome을 무작위로 절단하여 2,000 단편으로 구성하였으며, 감마선 $(^{60}/Co)$으로 유도된 7 돌연변이체의 발현을 정량적으로 관찰하였다. 클러스터 분석결과 발현된 408 유전자 중 27개가 감마선 유도 돌연변이체 모두에서 유의하게 발현이 증가되었다. 특히, 복구(mutL, mutM) 에너지 대사 (acsA, sdhB, pgk, yhjB, citB), protease (npr), 산화자극에 대한 환원 (HMM)관련 유전자들이 동시에 증가되었다. 이는 감마선 유도 돌연변이체들에서 자발적인 직/간접 복구 관련 유전자의 발현 증가는 방사선 노출 직후 보이는 stress response와는 다른 현상임을 나타내는 것으로 생각된다.