• Journal of Environmental Science International
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• v.7 no.5
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• pp.633-638
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• 1998

To determine whether the enhanced UV-B causes oxidative stress, and to test the relationship between plant growth response and biochemical defense response to UV-B, two soybean plants, Keunolkong, a highly UV-B susceptible cultivar, and Danyeubkong, a less UV-B susceptible cultivar, were subjected to the enhanced UV-B [daily dose : 0.06 (control) and 11.32 (enhanced UV-B) kJ $m^{-2}$ ; $UV-B_{BE}$] for 3 weeks. Contents of malondialdehyde and total carotenold were increased in Keunolkong compared with Danyeubkong by UV-B. In control plants, ascorbate level of Danyeubkong was 3 times higher than that of Keunolkong. The ratio of dehydroascorbate/ascorbate was highly increased in Keunolkong by UV-B . The activities of antioxidative enzyme such as superoxide dismutase, ascorbate peroxidase, monodehydroascorbate reductase and glutathione reductase were increased in both cultivars by UV-B. This results indicate that enhanced UV-B caused oxidative stress in both two cultivars, especially in Keunolkong. Susceptibility of two soybean cultivars to UV-B is closely related to the levels of antioxidants such as carotenoid and ascorbate.

• Journal of Radiation Protection and Research
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• v.24 no.4
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• pp.205-213
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• 1999

Effective dose conversion coefficients from unit activity radionuclides contaminated on the ground surface were calculated by using MCNP4A rode and male/female anthropomorphic phantoms. The simulation calculations were made for 19 energy points in the range of 40 keV to 10 MeV. The effective doses E resulting from unit source intensity for different energy were compared to the effective dose equivalent $H_E$ of previous studies. Our E values are lower by 30% at low energy than the $H_E$ values given in the Federal Guidance Report of USEPA. The effective dose response functions derived by polynomial fitting of the energy-effective dose relationship are as follows: $f({\varepsilon})[fSv\;m^2]=\;0.0634\;+\;0.727{\varepsilon}-0.0520{\varepsilon}^2+0.00247{\varepsilon}^3,\;where\;{\varepsilon}$ is the gamma energy in MeV. Using the response function and the radionuclide decay data given in ICRP 38, the effective dose conversion coefficients for unit activity contamination on the ground surface were calculated with addition of the skin dose contribution of beta particles determined by use of the DOSEFACTOR code. The conversion coefficients for 90 important radionuclides were evaluated and tabulated. Comparison with the existing data showed that a significant underestimates could be resulted when the old conversion coefficients were used, especially for the nuclides emitting low energy photons or high energy beta particles.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.117-125
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• 2015

Purpose: To investigate the relationship between early treatment response to definitive chemoradiotherapy (CRT) and survival outcome in patients with limited stage small cell lung cancer (LS-SCLC). Materials and Methods: We retrospectively reviewed 47 patients with LS-SCLC who received definitive CRT between January 2009 and December 2012. Patients were treated with systemic chemotherapy regimen of etoposide/carboplatin (n = 15) or etoposide/cisplatin (n = 32) and concurrent thoracic radiotherapy at a median dose of 54 Gy (range, 46 to 64 Gy). Early treatment volume reduction rate (ETVRR) was defined as the percentage change in gross tumor volume between diagnostic computed tomography (CT) and simulation CT for adaptive RT planning and was used as a parameter for early treatment response. The median dose at adaptive RT planning was 36 Gy (range, 30 to 43 Gy), and adaptive CT was performed in 30 patients (63.8%). Results: With a median follow-up of 27.7 months (range, 5.9 to 75.8 months), the 2-year locoregional progression-free survival (LRPFS) and overall survival (OS) rates were 74.2% and 56.5%, respectively. The mean diagnostic and adaptive gross tumor volumes were 117.9 mL (range, 5.9 to 447 mL) and 36.8 mL (range, 0.3 to 230.6 mL), respectively. The median ETVRR was 71.4% (range, 30 to 97.6%) and the ETVRR >45% group showed significantly better OS (p < 0.0001) and LRPFS (p = 0.009) than the other group. Conclusion: ETVRR as a parameter for early treatment response may be a useful prognostic factor to predict treatment outcome in LS-SCLC patients treated with CRT.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3973-3976
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• 2012

Background: The aim of this study was to evaluate the efficacy and toxicity of long-term, low-dose oral etoposide as an advanced treatment option in patients with platinum resistant epithelial ovarian cancer. Materials and Methods: For the purposes of this study, 51 patients with histologically-confirmed, recurrent or metastatic platinum-resistant epithelial ovarian cancer (EOC) treated at six different centers between January 2006 and January 2011 were retrospectively evaluated. Patients were treated with oral etoposide (50 mg/day for a cycle of 14 days, repeated every 21 days). Results: Among the 51 platinum-resistant patients, 17.6% demonstrated a partial response and 25.5% a stable response. The median progression-free survival (PFS) was 3.9 months (95% CI, 2.1-5.7), while the median overall survival was 16.4 months (11.8.20.9). No significant relationship was observed between the pre-treatment CA 125 levels, post-treatment CA-125 levels and the treatment response rates (p=0.21). Among the 51 patients who were evaluated in terms of toxicity, grade 1 or 4 hematologic toxicity was observed in 19 (37.3%); and grade 1-4 gastrointestinal toxicity occurred in 15 patients (29.4%). Conclusions: Chronic low-dose oral etoposide treatment is generally effective and well-tolerated in platinum-resistant ovarian cancer patients.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.53-63
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• 2006

The increased risk of cancer with exposure to low-dose radiation was estimated through longitudinal study for radiation workers at the nuclear power plants in Korea. The radiation dose data were collected from the Radiation Safety Management System(RSMS) of the Korea Hydro & Nuclear Power Co., Ltd(KHNP). The cancer risks with radiation exposure were evaluated in terms of relative mortality ratios(RMR) and relative incidence ratios(RIR) to the unexposed employees at the nuclear power plants, and of the standardized mortality ratios(SMR) and standardized incidence ratios(SIR). There were no significant increases of canters of all sites in the exposed group either in RIR[1.08, 95% confidence interval(CI) 0.74-1.58] or in RMR[1.21, CI 0.70-2.08]. Neither SIR[0.81, CI 0.28-0.96] nor SMR[0.86, CI 0.66-1.10] significantly deviated from 1.0 for cancers of all sites. The trend analysis did not identify evident dose-response relationship due to insufficient numbers of the cases. Consequently, it is concluded that increases in cancer risks in the radiation worker group exposed to low doses at the nuclear power plants in Korea are not identified at this time.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1991-1999
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• 2021

The response changes of the specific growth rate of Lemna minor duckweed was modeled using the logarithms of frond numbers on tritium activity concentration and gamma radiation dose from cobalt 60. The concept of average specific growth rate depends on the general exponential growth pattern, where toxicity is estimated based on the effect on the growth rate. One of the main questions of the effect of the radiation dose on duckweed is how to correlate the effect of beta radiation with the effect of any other radiation for modeling radiation on Lemna minor. Experimental data were extrapolated by utilizing the OECD guidelines. A linear relationship of absorbed dose and activity concentration was obtained for the average dependency growth rate of Lemna minor as D = (0.1257)·A^0.585. The dose rate of gamma irradiation from ⁶⁰Co increases with tritium activity dependence, on the specific growth rate of the Lemna minor duckweed. An increase in the tritium activity causes a decrease in the specific growth rate of the Lemna minor duckweed. It indicates that as the quantity of the beta radiation dose increase in Lemna minor duckweed, a higher quantity of gamma radiation will be required to cause the same effect in the specific growth rate of Lemna minor duckweed. The relation between the inhibition of the Lemna minor seedling growth and gamma and beta radiation dosage agrees roughly with that between the decrease of survival rate or fertility and dosage.

• Journal of Life Science
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• v.19 no.6
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• pp.799-803
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• 2009

The killing of male germ cells by radiation and other toxicants has recently been attributed to apoptosis, but a critical evaluation of the presence of the different features of apoptosis in each epithelial stage has not been performed. In this study, mouse testes exposed to radiation were examined by light microscopy and terminal transferase-mediated end labeling (TUNEL) with periodic acid-Schiff (PAS) stains to determine whether the cells were apoptotic according to several criteria. Apoptosis was easily recognized by the presence of peroxidase-stained, entirely apoptotic bodies. In the TUNEL-positive cells or bodies, the stained products correlated precisely with the typical morphologic characteristics of apoptosis as seen at the light microscopic level. The changes that occurred from 0 to 24 hours after exposing the mice to 2 Gy of gamma-rays (2 Gy/min) were examined. The numbers of apoptotic cells reached a peak at 12 hours after irradiation and then declined. The mice that received 0-8 Gy of gamma-rays were examined 8 hours after irradiation. Dose-response relationships were generated for each stage of the epithelial cycle by counting TUNEL-positive cells. The dose-response curves were linear- quadratic [y=(-0.014${\pm}$0.009)$D^{2}$+(0.31${\pm}$0.697)D+0.3575. Where y=the number of apoptotic cells per seminiferous tubule, and D=the irradiation dose in Gy, $r^{2}$=0.9] and there was a significant relationship between the frequency of apoptotic cells and the radiation dose. Although the maximum response was produced by 8 Gy, even 0.5 Gy induced marked changes. These changes were most pronounced in B spermatogonia of stage V and the spermatocyte at the mitotic cells of stage XII.

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.99-104
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• 2001

To determine if micronucleus (MN) assay could be used to predict the absorbed dose of victims after accidental radiation exposure, we carried out to assess the absorbed dose depending on the numerical changes of MN in human peripheral blood lymphocytes after $^{60}Co\;{\gamma}-rays$ exposure in the range of 0.25 to 1 Gy, respectively. The MNs were observed at very low doses, and the numerical changes according to doses. Satisfactory dose-effect calibration curve is observed after low dose irradiation of human lymphocytes in vitro. When plotting on a linear scale against radiation dose, the line of best fit was $Y=(0.02{\pm}0.0009)+(0.033{\pm}0.010)D+(0.012{\pm}0.012)D^2$. The dose-response curve for MN induction immediately after irradiation was linear-quadratic and has a significant relationship between the frequencies of MN and dose. These data show a trend towards increase of the numbers of MN with increasing dose. The number of MN in lymphocytes that were observed in the control group is $0.1610{\pm}0.0093/cell$. Accordingly, MN assay in human peripheral lymphocytes could be a useful in viva model for studying radio-protective drug sensitivity or screening test, microdosimertic indicator and radiation-induced target organ injury. Since MN assay is simple, rapid and reproducible, it will also be a biodosimetric indicator for individual dose assessment after accidental exposure.

• Radiation Oncology Journal
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• v.20 no.4
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• pp.303-308
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• 2002

Purpose : To determine the optimal radiation dose in a localized non-Hodgkin's lymphoma of the head and neck in the treatment setting for combined chemoradiotherapy. Materials an Methods :Fifty-three patients with stage I and II diffuse large ceil non-Hodgkin's lymphoma of the head and neck, who were treated with combined chemoradiotherapy between 1985 and 1998 were retrospectively reviewed. The median age was 49 years, and the male-to-female ratio was approximately 1.6. Twenty-seven patients had stage 1 disease and 26 had stage II. Twenty-three patients had bulky tumors $(\geq5\;cm)$ and 30 had non-bulky tumors (<5 cm). The primary tumors arose mainly from an extranodal organ $(70\%)$, most cases involving Waldeyer's ring $(90\%)$. All patients except one were initially treated with $3\~6$ cycles of chemotherapy, which was followed by radiotherapy. Radiation was delivered either to the primary tumor area alone $(9\%)$ or to the primary tumor area plus the bilateral neck nodes $(91\%)$ with a minimum dose of 30 Gy $(range\;30\~60\;Gy)$. The failure patterns according to the radiation field were analyzed, and the relationship between the dose and the in-field recurrence was evaluated. Results : The 10-year overall survival and the 10-year disease free survival rates were similar at $75\%\;and\;76\%$, respectively. A complete response (CR) after chemotherapy was achieved in 44 patients $(83\%)$. Subsequent radiotherapy showed a CR in all patients. Twelve patients $(23\%)$ had a relapse of the lymphoma after the initial treatment. Two of these patients had a recurrence inside the radiation field. No clear dose response relationship was observed and no significant prognostic factors for the in-field recurrences were identified because of the small number of in-field recurrences. However, for patients with tumors <5 cm in diameter, there were no in-field recurrences after a radiation dose 30 Gy. The 2 in-field recurrences encountered occurred in patients with a tumor $\geq5\;cm$. Conclusion .A dose of 30 Gy is sufficient for local control in patients with a non-bulky (<5 cm), localized, diffuse large cell non-Hodgkin's lymphoma when combined with chemotherapy. An additional boost dose in the primary site is recommended for patients with bulky tumors $(\geq5\;cm)$.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.3
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• pp.1-12
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• 2010

Objective : Samulatang (herbal description) is much used for women's disease in Korean Traditional Medicine. The aim of this study is to evaluate reproductive toxic effect by Samultang in pregnant rats and fetuses, and ascertain a dose-response relationship Method : Pregnant Sprague-Dawley rats were administered with the Samultang at single, double and quadruple dose for 20 days, orally. Pregnant rats were sacrificed at 20th day of gestation, and observed internal and reproductive organs. Live fetuses of gestation were randomly selected and fixed in 95% ethanol. Fetuses were stained with alcian blue and alizarin red S. We observe maternal body weight,, index associated pregnancy, and skeletal malformations in fetus Result : Maternal body weight of Samultang treated group has increased, side effect was not found in maternal body compared to that of control group. There were no significant difference in internal and reproductive organs. Double concentration administered group had lowest value in number of implantation, live fetuses, implantation rate and delivery rate, Also double concentration administered group showed higher early and late resorption rate than the other group. But, these are not significant. In the sex ratio, number of females, bigger than number of males in all Samultang administered groups. The fetuses of dams treated with Samultang didn't showed external and skeletal malformation. Vertebral and sternal variations were observed in single, double and quadruple concentration administered group but, compared to the control, those variations were insignificant. There were no significant changes in number of ribs, cervical, thoracic, lumber, sacral and caudal vertebrae Conclusion : Samultang is not expected to affect on pregnant rats and fetus about maternal body weight and number of live fetuses. There were no significant changes in organ weight, reproductive organs. Although skeletal variations were showed in vertebrae and sternum, treated groups were shown insignificant changes in skeletal variation