• Carbon letters
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• 제16권1호
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• pp.41-44
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• 2015

We report the preparation of sulfonated reduced graphene oxide (SRGO) by the sulfonation of graphene oxide followed by radiation-induced chemical reduction. Graphene oxide prepared by the well-known modified Hummer's method was sulfonated with the aryl diazonium salt of sulfanilic acid. Sulfonated graphene oxide (SGO) dispersed in ethanol was subsequently reduced by ${\gamma}$-ray irradiation at various absorbed doses to produce SRGO. The results of optical, chemical, and thermal analyses revealed that SRGO was successfully prepared by ${\gamma}$-ray irradiation-induced chemical reduction of the SGO suspension. Moreover, the electrical conductivity of SRGO was increased up to 2.94 S/cm with an increase of the absorbed dose.

• International Journal of Contents
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• 제8권4호
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• pp.64-69
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• 2012

The heart is a major dose-limiting organ for radiotherapy of cancer in the thoracic region. The purpose of this study was to examine the protective effect of tranilast on the radiation-induced heart fibrosis model using the C57BL/6 murine strain. A significant reduction in the expression of TGF-${\beta}1$, collagen type I and collagen type III was observed in the radiation plus tranilast group. The authors also suggest the use of tranilast in a clinical trial for the prevention of radiation-induced heart fibrosis.

• BMB Reports
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• 제47권10호
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• pp.575-580
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• 2014

In this study, we investigate whether arsenite-induced DNA damage leads to p53-dependent premature senescence using human glioblastoma cells with p53-wild type (U87MG-neo) and p53 deficient (U87MG-E6). A dose dependent relationship between arsenite and reduced cell growth is demonstrated, as well as induced ${\gamma}H2AX$ foci formation in both U87MG-neo and U87MG-E6 cells at low concentrations of arsenite. Senescence was induced by arsenite with senescence-associated ${\beta}$-galactosidase staining. Dimethyl- and trimethyl-lysine 9 of histone H3 (H3DMK9 and H3TMK9) foci formation was accompanied by p21 accumulation only in U87MG-neo but not in U87MG-E6 cells. This suggests that arsenite induces premature senescence as a result of DNA damage with heterochromatin forming through a p53/p21 dependent pathway. p21 and p53 siRNA consistently decreased H3TMK9 foci formation in U87M G-neo but not in U87MG-E6 cells after arsenite treatment. Taken together, arsenite reduces cell growth independently of p53 and induces premature senescence via p53/p21-dependent pathway following DNA damage.

• Journal of Ginseng Research
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• 제35권3호
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• pp.261-271
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• 2011

Chemical radiation protection is an important strategy to protect living beings against the deleterious effects of radiation. In the present study, the radioprotective effect of hydro-alcoholic extract of Panax ginseng extract (PGR-HAE) was studied on radiation-induced deleterious alterations in Swiss albino mice. Oral administration of such extract (25 mg/kg b wt/day/animal) for 5 consecutive days, half an h. before whole-body exposure to 6 Gy gamma radiation, enhanced the 30 days survival and also inhibited the radiogenic sickness, weight loss and life shortening. PGR-HAE ameliorated radiation induced depletion in blood constituents at different necropsy intervals between 12 h to 30 d, and significantly increased the number of femoral spleen colony forming units that survived after irradiation. Furthermore, it checked depletion of glutathione and antioxidant enzymes (superoxide dismutase, catalase, and glutathione S-transferase) as well as elevation of lipid peroxidation (LPO) level in blood and liver. The significant reduction in the yield of LPO demonstrates that PGR-HAE protects the membranes against radiation-induced oxidative damage. These findings conclude that such plant extract provides significant radioprotection, and it may be potentially valuable in the prevention of injuries caused during planned and unplanned radiation exposure.

• Journal of Radiation Protection and Research
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• 제20권2호
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• pp.97-102
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• 1995

인체 말초 혈액 림프구에서 저선량의 감마선에 의해 유도되는 적응 반응을 관찰하였다. 인체 림프구를 저선량의 감마선(priming dose 0.01Gy) 을 조사한 후 여러 시간 간격 후 고선량 (challenging dose, 1.5Gy) 을 조사하였다. 저선량을 미리 조사한 림프구와 조사하지 않은 림프구에서 발생된 미세핵의 빈도를 계수하였다. 비세핵 발생 빈도는 저선량 조사 4시간 후 고선량을 조사하였을 때 최대 감소치를 보였다. 저선량과 고선량 조사 시간차가 7시간 또는 20시간이었을 때 미세핵 발생 빈도는 약간 감소하였으나 유의성은 없었다. 본 연구에서는 $G_0$상태의 세포주기에서 저선량을 조사하였을 경우 적응 반응이 나타나는 것이 관찰 되었다. 미세핵 분석법은 실험 방법이 비교적 간단하고, 기타 염색체 분석법에 비하여 빠른 시간내 결과를 도출 할 수 있어 추후 방사선에 대한 적응 반응의 연구에 유용한 지표가 될 수 있을 것이다.

• 대한방사선기술학회지:방사선기술과학
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• 제7권1호
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• pp.23-33
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• 1984

In the present study, we determined reduction value of radiation on chest film by film method and made a reduction curves. The reduction radio in exposure to radiation was induced by comparative investigation of characteristic curves and reduction one. Basing on these result, we could reduce a radiation dose on body surface in 50% at the time of chest radiography, if 17.8mm aluminium or 0.87mm copper filter were used in addition to conventional filter at 140KV tube voltage. The present study further revealed that the additional use of the aluminium or copper filter at the time of high voltage radiography in chest facilitates to identify an image of some pathologic focus overlapping wist clavicle and ribs.

• Radiation Oncology Journal
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• 제33권4호
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• pp.328-336
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• 2015

Purpose: Past studies have reported that S-allylcysteine (SAC) inhibits the migration and invasion of cancer cells through the restoration of E-cadherin, the reduction of matrix metalloproteinase (MMP) and Slug protein expression, and inhibition of the production of reactive oxygen species (ROS). Furthermore, evidence is emerging that shows that ROS induced by radiation could increase Met activation. Following on these reports of SAC and Met, we investigated whether SAC could suppress Met activation. Materials and Methods: Wound healing, invasion, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT), soft agar colony forming, western blotting, and gelatin zymography assays were performed in the human nasopharyngeal cancer cell lines HNE1 and HONE1 treated with SAC (0, 10, 20, or 40 mM) and hepatocyte growth factor (HGF). Results: This study showed that SAC could suppress the migration and invasion of HNE1 and HONE1 cell lines by inhibiting p-Met. An increase of migration and invasion induced by HGF and its decrease in a dose dependent manner by SAC in wound healing and invasion assays was observed. The reduction of p-Met by SAC was positively correlated with p-focal adhesion kinase (p-FAK) and p-extracellular related kinase (p-ERK in both cell lines). SAC reduced Slug, MMP2, and MMP9 involved in migration and invasion with the inhibition of Met-FAK signaling. Conclusion: These results suggest that SAC inhibited not only Met activation but also the downstream FAK, Slug, and MMP expression. Finally, SAC may be a potent anticancer compound for nasopharyngeal cancer treated with radiotherapy.

• 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.

• Natural Product Sciences
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• 제19권2호
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• pp.127-136
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• 2013

Ionizing radiation, including that evoked by gamma (${\gamma}$)-rays, induces oxidative stress through the generation of reactive oxygen species, resulting in apoptosis, or programmed cell death. This study aimed to elucidate the radioprotective effects of hyperoside (quercetin-3-O-galactoside) against ${\gamma}$-ray radiation-induced apoptosis in Chinese hamster lung fibroblasts, V79-4 and demonstrated that the compound reduced levels of intracellular reactive oxygen species in ${\gamma}$-ray-irradiated cells. Hyperoside also protected irradiated cells against DNA damage (evidenced by pronounced DNA tails and elevated phospho-histone H2AX and 8-oxoguanine content) and membrane lipid peroxidation. Furthermore, hyperoside prevented the ${\gamma}$-ray-provoked reduction in cell viability via the inhibition of apoptosis through the increased levels of Bcl-2, the decreased levels of Bax and cytosolic cytochrome c, and the decrease of the active caspase 9 and caspase 3 expression. Taken together, these results suggest that hyperoside defend cells against ${\gamma}$-ray radiation-induced apoptosis by inhibiting oxidative stress.

• 분석과학
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• 제28권1호
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• pp.8-16
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• 2015

We prepared a novel electrochemical gas sensor (EG sensor) based on interdigitated electrode (IDE) coated with vinyl ionic liquids (ILs) as electrolyte and Pt-Ru-Mo/MWNT electrocatalysts for occurring redox-active of CNCl gas. The vinyl ILs such as 1-butyl-3-(vinylbenzyl)imidazolium chloride, $[BVBI]^+Cl^-$, and 3-hexyl-1-vinylimidazolium bromide, $[HVI]^+Br^-$, were synthesized by $SN_2$ reaction in order to use electrolyte. The Pt-Ru-Mo/MWNT electrocatalysts were also prepared by one-step radiation-induced reduction of metal ions in the presence of MWNTs as supports. The fabricated EG sensor with vinyl ILs electrolyte was evaluated through optical microscopy (OM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The prepared EG sensor is clearly detected over 2.0 ppm CNCl gas and is exhibited a liner relationship between current and concentration over a region of 10-100 ppm.