• Nuclear Engineering and Technology
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• 제50권3호
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• pp.526-530
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• 2018

Human fingernails were used to estimate the radiation dose via electron paramagnetic resonance measurements of radiation-induced radicals. The limiting factors in this research were mechanically induced electron paramagnetic resonance signals due to the mechanical stress during the preparation of the samples. Therefore, different treatment methods of fingernails were used to reduce the mechanically induced signals. The results demonstrate that the mechanically induced and radiation-induced signals have apparently different microwave power saturation behaviors. In addition, the mechanically induced signal shows a fading evolution over time and reaches a constant value. Chemical treatment using the different reagents showed that the minimum mechanically induced signal was obtained using the dithiothreitol reagent. The dose-response curves of the samples treated with dithiothreitol for 30 minutes demonstrated a greater linearity than those of samples treated for 5 minutes. Therefore, to find an unknown absorbed dose in a fingernail sample using a calibration curve, we recommend adopting the mentioned chemical treatment procedure to reduce the uncertainty.

• Biomolecules & Therapeutics
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• 제6권2호
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• pp.119-129
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• 1998

The dose-response effect of polysaccharide extracts(PS-1) from Artemisia iwayomogi was inves-tigated under various hepatic disease models. Silymarin, DDB and UDCA were used as reference compounds. We found that the maximal effective dose of PS-1 was 100 mg/kg b.wt. in $CCl_4$-induced hepatotoxicity, D-galactosamine-induced hepatitis, in ANIT-induced cholestasis and 300 mg/kg b.wt. in $CCl_4$-induced chronic liver disease, 30 mg/tg b.wt. in chronic bile duct ligation and chronic ethanol fatty liver. These findings suggest that PS-1 fraction protects the hepatocyte against various hepatic injuries, and this fracton might be of therapeutic value.

• Animal cells and systems
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• 제4권3호
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• pp.293-297
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• 2000

The present investigation was performed to elucidate the effect of pretreatment with low dose ultraviolet radiation (UV) and ethyl methanesulfonate (EMS) on cell survival by trypan blue dye exclusion method and plasma membrane glycoconjugates by lectin-cytochemistry in sarcoma 180 (S180) cells. Pretreatment with 2 J/$m^2$ UV or 2 mM EMS increased the percentage of survival of cells subsequently treated with high dose UV (10 or 20 J/$m^2$) or EMS (10 or 20 mM), respectively. Staining intensity of concanavalin A (Con A) of the cells pretreated with 2J/$m^2$ UV or 2 mM EMS and subsequently treated with 10 or 20 mM EMS was stronger than that of the cellstreated with 10 or 20 mM EMS. These results suggest that there is an adaptive response on cell survival to EMS or UV in S180 cells. And the results show a change in mannose-containing glycoconjugates of plasma membrane in S180 cells pretreated with EMS or UV and subsequently treated with EMS.

• Radiation Oncology Journal
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• 제36권3호
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• pp.172-181
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• 2018

Successful anticancer strategies require a differential response between tumor and normal tissue (i.e., a therapeutic ratio). In fact, improving the effectiveness of a cancer therapeutic is of no clinical value in the absence of a significant increase in the differential response between tumor and normal tissue. Although radiation dose escalation with the use of intensity modulated radiation therapy has permitted the maximum tolerable dose for most locally advanced cancers, improvements in tumor control without damaging normal adjacent tissues are needed. As a means of increasing the therapeutic ratio, several new approaches are under development. Drugs targeting signal transduction pathways in cancer progression and more recently, immunotherapeutics targeting specific immune cell subsets have entered the clinic with promising early results. Radiobiological research is underway to address pressing questions as to the dose per fraction, irradiated tumor volume and time sequence of the drug administration. To exploit these exciting novel strategies, a better understanding is needed of the cellular and molecular pathways responsible for both cancer and normal tissue and organ response, including the role of radiation-induced accelerated senescence. This review will highlight the current understanding of promising biologically targeted therapies to enhance the radiation therapeutic ratio.

• 한국방사선학회논문지
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• 제12권1호
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• pp.79-83
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• 2018

본 논문에서는 OSL 도트 선량계의 교정인자, 흡수선량 선형성, 피크전압 선형성, 각도 변화에 의한 흡수선량 변화를 측정하고 분석했다. 의료용 X 선발생 장치를 사용하여 조사에 노출 선량 보정 계수, 흡수선량 선형성, 피크 전압 선형성은 모두 IEC-62387-1 (2007) 기준을 만족하였다. 기준 방사선 노출과 관련하여 0도, 30도 및 60도에서 선량계 방향에 대한 기준은 -29 % (${\pm}30^{\circ}$) 및 + 67 % (${\pm}60^{\circ}$)이었다. 30도에서 측정된 값은 기준보다 -8 % 낮고 60도에서 기준보다 -18 % 낮게 나타났다. 그러므로 OSL 도트 선량계 사용 시 방향에 따른 영향을 보정하여야 한다.

• Journal of Preventive Medicine and Public Health
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• 제33권2호
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• pp.165-173
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• 2000

Objectives : To assess the availability of the glycophorin A (GPA) assay to detect the biological effect of ionizing radiation in workers exposed to low-doses of radiation. Methods : Information on confounding factors, such as age and cigarette smoking was obtained on 144 nuclear power plant workers and 32 hospital workers, by a self-administered questionnaire. Information on physical exposure levels was obtained from the registries of radiation exposure monitoring and control at each facility. The GPA mutant assay was performed using the BR6 method with modification by using a FACScan flow cytometer. Results : As confounders, age and cigarette smoking habits showed increasing trends with GPA variants, but these were of no statistical significance. Hospital workers showed a higher frequency of the GPA variant than nuclear power plant workers in terms of the NO variant. Significant dose-response relationships were obtained from in simple and multiple linear regression models. The slope of the regression equation for nuclear power plant workers was much smaller than that of hospital workers. These findings suggest that there may be apparent dose-rate effects. Conclusion : In population exposed to chronic low-dose radiation, the GPA assay has a potential to be used as an effective biologic marker for assessing the bone marrow cumulative exposure dose.

• 한국어병학회지
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• 제17권3호
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• pp.217-222
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• 2004

This study was performed to investigate the immunological side effects of chloramphenicol (CAP) on olive flounder, Paralichthys olivaceus. To investigate immunological effects on olive flounder, we determined the changes of chemiluminescence (CL) response of flounder kidney-derived leucocyte after the treatment of CAP in vivo and in vitro. The CL activity was significantly decreased in a dose-dependent manner during the treatment of CAP in vitro. Similarly, a dose-dependent reduction of CL response, although not significant, were observed during the treatment of CAP in vivo. The results suggest that CAP reduced the function of flounder phagocytosis in vivo and in vitro, indicating the immunosuppressive ability of CAP.

• 대한방사선기술학회지:방사선기술과학
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• 제18권1호
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• pp.71-75
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• 1995

In order to establish the photographic effects and sensitivity of various screens, fluorescence meter is used with convenience. When the radiation quality has been fixed the fluorescence has increased in proportion to X-ray dose. However, the response of fluorescence meter has the dependency of X-ray quality in accordance with KVP. as well as the difference of screen and scatter fraction can influence on the response of fluorescence meter. Using accurate fluorescence meter as a radiation detecter and as for a proper supervision the sensitive materials, we have to aware of the meter's dependency of X-ray quality and the scatter fraction.

• Asian-Australasian Journal of Animal Sciences
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• 제18권8호
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• pp.1098-1104
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• 2005

The trial was carried out on twenty-one Friesian cows at the end of eight months gestation, nine multiparous and twelve primiparous; allocated into three groups (1 control, 2 and 3 experimental). The same diet was administred to all three groups before partum (12.8 kg DM/head/day) and after partum (18.8 kg DM/head/day). The cows in groups 2 and 3 received two different daily quantities of amino-acid chelated chromium (0.6 and 1.2 mg Cr/kg DM) from 4 weeks prior to presumed parturition to 6 weeks after. The milk yield control was carried out at 15, 30, 42 and 60 days. All animals were immunised two weeks prior to the presumed parturition and two weeks after with the following antigens: ovalbumin and brucellergene. Blood samples were collected weekly to monitor humoral and cell-mediated immune responses. When analysing the results of antibody immunity (ovalbumin) in the sixth blood collection both treated groups significantly increased compared to group 1 (0.5230 and 0.4536 vs. 0.1812 OD; p<0.05). The results of the cell-mediated immune response (brucellergene) had significant differences (p<0.10) in correspondence to the third (between group 2 and control) and the fifth (between groups 3 and 2) blood collection. Significant differences in fat corrected milk were observed at 42 days between group 3 and the other two groups (31.01 vs. 26.99 and 28.66 kg/d, p<0.05) and at 60 days between group 3 and control (30.88 vs. 26.69 kg/d, p<0.05). Before partum and at partum a positive immune response was obtained with a lower dose of chromium. After partum a positive immune response, anti-OVA indicator, was obtained with the higher dose of chromium while, $\gamma$-IFN indicator, with the lower dose. A significant increase of the milk yield resulted at both 42 and 60 days with the highest level of chromium.

• Toxicological Research
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• 제8권2호
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• pp.191-203
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• 1992

The immunosuppressive effects of safrole were studied in female BALB/c mouse. Mice were given 100,200and 400mg safrole/kg daily for 14days and evaluated on day 15. The day 4 immunogloblin-M antibody response to T-dependent antigen, sheep red blood cells (SRBC) was inhibited dose-dependently in all doses studied. In vitro antibody response to polyclonal antigen, lipopolysaccharide (LPS) by spleen cell suspensions from safrole-treated mice were also significantly inhibited. When safrole was treated for 14days to mice, and mitogen-induced proliferation of splenocytes were assayed on day 15, there were significant suppression of responses to B-cell mitogen, LPS and T-cell mitogen concanavalin A(Con A) at a dose of 400mg safrole/kg. Direct addition of safrole on the splenocyte culture also produced a dose dependent suppression on in vitro antibody response to LPS, and mitogen-induced lymphoproliferatin at doses of 100,200,400 and 800${\mu}M$ safrole. The role of metabolic activation in safrole-induced suppression of in vitro antibody response was studied using splenocyte-hepatocyte coculture system. The suppression of in vitro antibody respose to LPS by safrole was not altered when safrole were incubated in the splenocyte-hepatocyte system for 4hr as compared with direct addition of safrole in splenocytes culture. Neither the addition of salicylamide, sulfotransferase inhibitor, nor the addation of inorganic sulfate, sulfation cofactor to the splenocyte-hepatocyte coculture, altered the suppression of antibody response by safrole. These results suggest that the immunosuppression by safrole may not by produced by the reactive metabolites which are mediated in carcinogenesis of safrole.