• 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.

• Radiation Oncology Journal
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• 제37권4호
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• pp.265-270
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• 2019

Purpose: Renal cell carcinoma (RCC) and melanoma have been considered 'radioresistant' due to the fact that they do not respond to conventionally fractionated radiation therapy. Stereotactic radiosurgery (SRS) provides high-dose radiation to a defined target volume and a limited number of studies have suggested the potential effectiveness of SRS in radioresistant histologies. We sought to determine the effectiveness of SRS for the treatment of patients with radioresistant brain metastases. Materials and Methods: We performed a retrospective review of our institutional database to identify patients with RCC or melanoma brain metastases treated with SRS. Treatment response were determined in accordance with the Response Evaluation Criteria in Solid Tumors. Results: We identified 53 radioresistant brain metastases (28% RCC and 72% melanoma) treated in 18 patients. The mean target volume and coverage was 6.2 ± 9.5 mL and 95.5% ± 2.9%, respectively. The mean prescription dose was 20 ± 4.9 Gy. Forty lesions (75%) demonstrated a complete/partial response and 13 lesions (24%) with progressive/stable disease. Smaller target volume (p < 0.001), larger SRS dose (p < 0.001), and coverage (p = 0.008) were found to be positive predictors of complete response to SRS. Conclusion: SRS is an effective management option with up to 75% response rate for radioresistant brain metastases. Tumor volume and radiation dose are predictors of response and can be used to guide the decision-making for patients with radioresistant brain metastases.

• 한국환경보건학회지
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• 제18권2호
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• pp.117-124
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• 1992

Pretreatment with low concentration of Bleomycin and Cadmium rendered Chinese Hamster Ovary Cells more resistant to the induction of chromosome aberration by subsequent high concentration of same agent, however Mitomycin C did not function in that way. The cells pre-exposed to low dose of Cadmitim did not show cross-resistance to challenge dose of Mitomycin C for the induction of chromosome aberration, but cells pre-exposed to Bleomycin showed cross resistance. And the cells pre-exposed to low dose of Mitomycin C showed cross resistance to challenge of Bleomycin, but Cadmium did not.

• Biomolecules & Therapeutics
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• 제16권4호
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• pp.299-305
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• 2008

Active cardiovascular anaphylactic response was induced in ovalbumin-sensitized, pithed Sprague-Dawley and Wistar rats. On intravenous administration of the antigen, ovalbumin, marked tachycardia and pressor responses were immediately elicited. Thereafter, a delayed long-lasting severe hypotensive response was observed. These anaphylactic cardiovascular responses were maximal 2-3 weeks after the sensitization, and the response was slightly diminished 6 weeks after sensitization. The immediate pressor response was blocked by a non-selective serotonin antagonist methysergide at a dose-dependent manner, but not by histamine receptor antagonists mepyramine (pyrilamine) or cimetidine. The delayed hypotension was reduced either by histamine $H_1$ receptor antagonist mepyramine or $H_2$ receptor antagonist cimetidine, both in a dose-dependent manner. The tachycardic response was not influenced by serotonin or histamine receptor antagonists examined in this study. Differently from the cardiovascular responses, there was no observable bronchial contraction in Sprague-Dawley rat trachea in contrast to Wistar rat where the trachea contracted to in vitro antigen challenge. The cardiovascular anaphylactic model seems to be useful for studying cardiovascular events that occur exclusively in peripheral heart-blood vessel systems. The involvement of two major anaphylactic mediators, serotonin and histamine, is partially demonstrated.

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.47-52
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• 2004

Recently, a new sintered pellet-type LiF:Mg,Cu,Na,Si TL detector which has a high sensitivity and good reusability, named KLT-300(KAERI LiF:Mg,Cu,Na,Si TL detector), was developed by the variation of the dopants concentrations and the parameters of the preparation procedure at KAERI (Korea Atomic Energy Research Institute). In this study, the thermoluminescent characteristics of the newly developed TL detectors were investigated. The sensitivity of the TL detector was compared with that of the TLD-100 by light integration. The dose linearity of the detector was tested from $10^{-6}$ Gy up to 30 Gy. The dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 keV to 662 keV. The result shows that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively was 0.0054. Lower limit of detection for the detector was investigated at 70 nGy by the Harshaw 4500 TLD Reader and the residual signal of the TL detector was found to be $0.57\%$.

• International Journal of Control, Automation, and Systems
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• 제1권3호
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• pp.282-288
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• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we found that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.