• Radiation Oncology Journal
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• v.26 no.3
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• pp.173-180
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• 2008

Purpose: The modification of radiation-induced apoptosis by EGCG, known as antioxidants or oxidants, was studied in mice spleens irradiated with a lethal dose. Materials and Methods: Male C57BL/6 mice were divided into control, irradiation-only, and EGCG (100 mg/kg i.p. 1 h before irradiation) pretreatment groups. The mice were irradiated with a single whole-body dose of 7 Gy. The apoptosis in the spleens after irradiation of the lethal dose were analyzed by TUNEL assay. In addition, the expression levels of the Bax and Bcl-2 proteins were quantified using a Western blotting method. Results: The induction of apoptosis was detected in the splenic white pulp. The highest level of apoptosis was detected at 8 hours after irradiation. No significant difference was identified by the apoptotic index (53.9% vs. 52.1%, p=0.328) and relative Bax protein expression (0.86 vs. 0.81, p=0.335), between the irradiation-only and EGCG pretreatment group, respectively. However, a lower Bax/Bcl-2 ratio (1.64 vs. 0.97, p=0.037) and higher relative expression level of Bcl-2 protein (0.57 vs. 0.82, p=0.037) was measured in the EGCG pretreatment group. Conclusion: The EGCG pretreatment neither decreased the radiation-induced apoptosis in mice splenocytes, nor induced additional apoptosis.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.747-754
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• 2000

DNA damages in post-mortem bovine muscle samples caused by gamma irradiation at doses of 1 to 10 kGy were determined by Comet assay. When the cell extract was prepared in a physical method and followed by neutral lysis and neutral electrophoresis, the optimal comet images could be obtained. DNA damages were evaluated from the mean tail length, the distributions of comet images in 4 groups divided by tail length and the relative damage index (RDI) values calculated from the distribution pattern. The mean tail length and RDI value were increased by increasing the irradiation dose, and the RDI value was found to be useful as an index for discriminating of irradiation and measuring the irradiated dose. Blind tests using Korean domestic (Hanwoo) and imported beef samples showed a higher RDI value for the latter. However, the value was lower than those of irradiated samples indicating that the cause of DNA damages in the imported beef samples might be not irradiation but low-temperature treatments. It was concluded from the results of this study that the irradiated beef and its irradiated dose could be detected and predicted by Comet assay.

• Imaging Science in Dentistry
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• v.39 no.3
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• pp.121-132
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• 2009

Purpose : To investigate the effects of 2-deoxy-D-glucose (2-DG) and quercetin (QCT) on gene expression of bone sialoprotein (BSP) and osteocalcin (OC) during the differentiation in irradiated MC3T3-E1 osteoblastic cells. Materials and Methods : When MC3T3-E1 osteoblastic cells had reached 70-80% confluence, cultures were transferred to a differentiating medium supplemented with 5 mM 2-DG or $10{\mu}M$ QCT, and then irradiated with 2, 4, 6, and 8 Gy. At various times after irradiation, the cells were analyzed for the synthesis of type I collagen, and expression of BSP and OC. Results : The synthesis of type I collagen in cells exposed to 2 Gy of radiation in the presence of 2-DG or QCT showed no significant difference compared with the control group within 15 days post-irradiation. When the cells were irradiated with 8 Gy, 2-DG facilitated the irradiation mediated decrease of type I collagen synthesis, whereas such decrease was inhibited by treating with QCT. During MC3T3-E1 osteoblastic cell differentiation, the mRNA expression of BSP and OC showed the peak value at 14 days and 21 days, respectively. 2-DG or QCT treatment alone decreased the level of BSP mRNA, but increased the OC mRNA level only at early time of differentiation (day 7). In the cells irradiated with 2, 4, 8 Gy, the mRNA expression of BSP and OC decreased at 7 days after the irradiation. The cells were treated with various dose of radiation in the presence of 2-DG or QCT, the mRNA level of both BSP and OC increased although this increase was observed at low dose of radiation (2 Gy) and at the early stage of differentiation. However, when the cells were exposed to 4, 6, or 8 Gy, the increase of BSP and OC mRNAs was detected only in cells co-incubated with QCT. Conclusion : This study demonstrates that 2-DG and QCT affect differently the expression of bone formation related factors, type I collagen, BSP, and OC in the irradiated MC3T3-E1 osteoblasic cells, according to the dose of radiation and the times of differentiation. Overall, the present findings suggest that 2-DG and QCT could have the regulatory roles as radiation-sensitizer and -protector, respectively.

• Applied Microscopy
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• v.23 no.2
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• pp.11-26
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• 1993

This experiment was performed to study the morphological responses of the pigment epithelial cell and the Bruch's membrane of the retina of rat following X-ray irradiation. Male rats were divided into normal and experimental groups. The heads of the rats, under sodium thiopental anesthesia, were exposed to 3,000 rads or 6,000 rads of radiation in a single dose, respectively. The source was a Mitsubishi Linear Accelerator ML-4MV. The target to skin distance was 80cm, and the. dose rate was 200 rads/min. The experimental groups were sacrificed on the 6th hour, 2nd and 6th day after X-ray irradiation. Under anesthesia, 1% glutaraldehyde-1% paraformaldehyde solution(0.1M Millonig's phosphate buffer, pH 7.3) was perfused through the left ventricle and ascending aorta. Pieces of the tissue taken from the posterior region of the retina were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde(0.1M Millonig's phosphate buffer, pH 7.3) and 1% osmium tetroxide(0.1M Millonig's phosphate buffer, pH7.3), and embedded in araldite mixture. The ultrathin sections contrasted with uranyl acetate and lead citrate were observed with JEM 100 CX-II electron microscope. The results were as follow; 1. The morphological changes of the pigment epithelial cells were not pronounced after exposure to 3,000 rads of X-ray. But on the 6th hour after exposure to 6,000 rads of X-ray, bulging nuclear membrane protruding into the cytoplasm and nuclear chromatin clumped into numerous masses along the nuclear membrane were observed. At the 2nd and 6th day post-irradiation, partial cytolysis or necrosis were seen. 2. The thickness of the Bruch's membrane of the experimental groups were increased in the time and dose range covered by this study, and splitting or diffusing basal laminae of the choriocapillary layer were observed frequently in the experimental group. Above results suggest that large amount(6,000 rads) of head irradiation induce direct hazardous effects on the pigment epitherial cells and Bruch's membrane of the retina of the rat, but pigment epithelial cells are more radioresistant than Bruch's membrane.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.128-136
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• 2015

This study investigated the effects of low-dose electron beam irradiation treatment on physicochemical and sensorial properties of imported navel oranges during storage at $3^{\circ}C$ for 45 days. The samples were irradiated at doses of 0.2, 0.4, 0.6, 0.8, and 1.0 kGy, and changes in their color values, hardness, Brix/acid ratio, total sugar contents, reducing sugar contents, vitamin C contents, and sensory evaluation were investigated. There were no significant differences between non-irradiated and irradiated samples in terms of color values, Brix/acid ratio, total sugar contents, total reducing sugar contents, and vitamin C contents. Hardness of irradiated sample at 1 kGy decreased significantly in the early storage period, but the difference between non-irradiated and irradiated samples decreased again at the end of storage. For the sensory evaluation, scores of color, sweetness, flavor, and overall acceptability decreased as irradiation dose and storage period increased. Samples irradiated at over 0.8 kGy showed low preference in all scores except color. These results suggest that electron beam irradiation below 0.6 kGy does not affect physicochemical and sensory properties; thus, electron beam irradiation up to 0.6 kGy in imported navel oranges is optimum for minimizing quality changes and disinfestation treatment simultaneously.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1005-1010
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• 1999

To study the shortening of rigor mortis and changes in the morphological properties of gamma-irradiated pre-rigor bovine muscle (M). Sternomandibularis during post mortem, this experiment was performed with a test of shear force and the observation of the ultrastucture of raw muscle. The time elapsed until maximum shear force values was shortened by gamma irradiation, depending upon the dose. The release of rigor mortis started earlier than control (non-irradiated muscle). A shortening of the length of the Z-line and the maintenance of the sarcomere length by gamma irradiation was observed. The breakdown of the perimysium of muscle bundles was observed more in irradiated samples than in the control. In conclusion, it is considered that gamma irradiation on pre-rigor beef shortens aging-period, improves tenderness and enhances the beef quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.25-29
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• 2004

The responses of soybean seeds were evaluated to accelerated aging and gamma irradiation with regard to germination, seed leakage, seed leachate component and dry weight of hypocotyl and primary root of the germinating seed. Accelerated aging significantly reduced the final germination rate while gamma irradiation increased the final germination rate. Furthermore, the interactive effects occurred that the final germination rate of 5-day aged seeds increased considerably in response to 4 Gy of gamma irradiation. The extent to which the electrolyte was leaked from the seeds (conductivity) was significantly affected by accelerated aging and showed a close negative correlation with the germination rate. Gamma irradiation, however, did not significantly affect the electrical conductivity of seed leachate. The accelerated aging significantly increased the concentrations of the particular electrolytes leaked from the seeds while the gamma irradiation did not affect those concentrations. Of the electrolytes leaked from the seeds, Ca and Mg showed relatively lower concentrations while K showed greater concentrations than others. Moreover, N and P showed similar responses to aging treatment. Aging treatment significantly affected dry weight (DW) of hypocotyls and primary root. Also, gamma irradiation decreased DW of hypocotyls and primary root, particularly for 8 Gy associated with 5 days aging treatment. The data were discussed in terms of the relationships of seed vigor with aging treatment and gamma irradiation.

• Imaging Science in Dentistry
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• v.38 no.4
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• pp.195-202
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• 2008

Purpose : To characterize the effects of 2-deoxy-D-glucose (2-DG) and quercetin (QCT) on gene expression of osteonectin (ON) and osteopontin (OP) in irradiated MC3T3-El cells. Materials and Methods : When MC3T3-El osteoblastic cells had reached 70-80% confluence, cultures were transferred to a differentiating medium supplemented with 5 mM 2-DG or 10 ${\mu}M$ QCT and then irradiated with 2, 4, 6, and 8 Gy. At various times after irradiation, the cells were analyzed for the expression of bone mineralization genes such as ON and OP. Results : The mRNA expression of both ON and OP was increased according to the culture time in the differentiation medium, and the increase of the genes peaked at 14 days after the differentiation induction. In the case of OP, the increase of mRNA expression was maintained to 28 days after the differentiation, while the mRNA level of ON was reduced to the basal level at the same time. Irradiation adding 2-DG showed a significant peak value in the expression pattern of ON at 4 Gy 7 days after irradiation. Irradiation adding QCT increased the mRNA expression of ON and OP in a dose-dependant manner, but irradiation adding 2-DG did not show any differences between the control and experiments 14 days after irradiation. Irradiation adding QCT increased significantly the expression patterns of ON 21 days after irradiation. Conclusion : The results showed that QCT acted as a radiosensitizer in the gene expression of ON and OP during differentiation of the late stage of irradiated MC3T3-E1 osteoblastic cells in vitro. (Korean J Oral Maxillofac Radiol 2008; 38: 195-202)

• Journal of Radiation Protection and Research
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• v.42 no.4
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• pp.177-188
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• 2017

Background: Radiation-induced pneumonitis and pulmonary fibrosis are common dose-limiting complications in patients receiving radiotherapy for lung, breast, and lymphoid cancers. In this study, we investigated the characteristics of effective immune cells related to pneumonitis and fibrosis after irradiation. Materials and Methods: After anesthesia, the whole thorax of C57BL/6 mice was irradiated at 14 Gy. The lung tissue and bronchoalveolar lavage fluid were collected at defined time points post-irradiation for the determination of histological and immunohistochemical analysis and inflammatory cell population infiltrated into the lung. Results and Discussion: Whole thoracic irradiation increased the deposition of extracellular matrix (ECM), lung weight, and pleural effusions, which started to die from 4 months later. At 4 months after irradiation, the numbers of macrophages and lymphocytes as well as neutrophils were increased dramatically in the lung. Interestingly, the macrophages that were recruited into the lung after irradiation had an enlarged foamy morphology. In addition, the expressions of chemokines (CCL-2, CCL-3, CXCL-10) for the attraction of macrophages and T cells were higher in the lung of irradiated mice. The high expressions of these chemokines were sustained up to 6 months following irradiation. In thoracic irradiated mice, infiltrated macrophages into the lung had the high levels of Mac-3 antigens on their surface and upregulated the hallmarks of alternatively activated macrophages such as arginase-1 and CD206. Furthermore, the levels of IL-4 and IL-13 were higher in a BAL fluid of irradiated mice. Conclusion: All results show that thoracic irradiation induces to infiltrate various inflammation-related immune cells, especially alternatively activated macrophages, through enhancing the expression of chemokines, suggesting that alternatively activated macrophages are most likely important for leading to pulmonary fibrosis.

• The Korean Journal of Physiology
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• v.5 no.1
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• pp.51-58
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• 1971

In an attempt to further clarify the effect of X·irradiation on the activity of surfactant in rabbits, X-ray in dose of 900r was irradiated to the lung tissues of rabbits in vitro. Tension-area diagram of the lung extract was recorded automatically by a modified Langmuir-Wilhelmy balance with a synchronized recording system designed in this department. The surface tension of the lung extract was measured at 1,3,5,24 and 48 hours post-irradiation, and the results were compared with the non·irradiated normal group. The result$ thus obtained are summarized as follows: I The maximal surface tension, minimal surface tension, width of the tension·area diagram at the surface area of 40% in the lung extract and stability index of the normal rabbit long extract were 40.73 dynes/cm, 8.96 dynes/cm, 20.71 dynes/cm and 1.28, respectively. II. When 900r of X-ray was irradiated to the lung in vitro, 1) The maximal and minimal surface tensions did not differ noticeably from the normal at 1,3, and 5 post-irradiation hours, but the minimal surface tension increased significantly at 24 and 48 hours Post-irradiation. 2) The width of the tension area at the surface area of 40% showed a tendency of decrease throughout the experiment. 3) The stability index showed no significant change at 1,3 and 5 post-irradiation hours,but at 24 and 48 hours post-irradiation a significant decrease was observed comparing with the control. III. Activity of surfactant was significantly depressed by X·irradiation in vitro especially at 24 and 48 hours post-irradiation.