• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.183-197
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• 1991

After single fraction of 2, 5, 10 Gy irradiation on submandibular gland of 40 male rats, weighing 150gm, respectively, these animal were sacrificed two hours after 0.1㎎/g bromodeoxyuridine (Sigma) peritoneal injection in 1, 3, 7, 15 hours, 1, 3, 7 days after irradiation. And excised submandibular gland were fixed in Carnoy's and Bouin's solution for 2 hours. Paraffin sections were stained with H&E, and PAS for the observation of the change of salivary gland tissue, and with Feulgen for the study of the DNA distribution, and immunohistochemically stained with anti-bromodeoxyuridine (Sanbyo Co.) for detection of DNA synthetic cells in order to study the distribution of DNA synthetic cells of salivary gland tissue and endothelium after irradiation in 5 different sites of 6 slides on X 200 high power field. The results were as followings. 1. In PAS staining 3 days after 5Gy irradiation, decreased mucine secretion of serous cells were found, and 7 days after l0Gy irradiation, decreased mucine secretion of mucous cells were found. 2. In histopathologic features, degeneration of serous cells were found in 3 days after 2 Gy irradiation and there was little change in mucous cells and excretory duct cells. 3. In Feugen staining, 3 days after 2 Gy, 5 Gy irradiation, more high percentage of DNA synthetic cells were found in intercalated duct cells, striated duct cells and excretory duct cells than in BrdU staining. 4. In immunohistochemical features, DNA synethsis of serous cells and granular convoluted tubular cells abruptly decreased in early period after irradiation and showed no recovery in 7 days after irradiation but there was an increase in DNA synthesis of intercalated duct cells, striated duct cells and excretory duct cells, which have less S-phase cells comparatively, in 7 days after 2 Gy, 5 Gy irradiation. 5. In immunohistochemical features, the DNA synthesis of endothelial cells was continuously decreased after irradiation but showed slight increase in 7 days after 2 Gy and S Gy irradiation.

• Imaging Science in Dentistry
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• v.36 no.1
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• pp.33-40
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• 2006

Purpose : To investigate clusterin expression in the acini and ductal cells of rat submandibular glands after Co-60 gamma irradiation. Materials and Methods : The male Sprague-Dawley rats weighing approximately 250 gm were divided into control and experimental groups. The experimental group was irradiated with a single absorbed dose of 2, 5, 10, and 15 Gy on the head and neck region. All the rats were sacrificed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimens including the submandibular gland were sectioned and observed using a immunohistochemical method. Results : In the 2 Gy group, clusterin expression was similar to that of the control group at 1 day after irradiation and it was observed in the striated ductal cells at 3 days after irradiation. In the 5 Gy group, clusterin expression was observed in the striated ductal cells at 1 day after irradiation and gradually increased in the 10 and 15 Gy groups. In the 15 Gy group, clusterin expression was prominent in the striated ductal cells at 1 day after irradiation, but it gradually decreased with the experimental period. The destruction of the striated ductal cells was observed in the 2 Gy group at 21 days after irradiation and in the 5, 10, and 15 Gy groups at 7 days after irradiation. The destruction of the acinar cells was observed in the 2 Gy group at 28 days after irradiation and in the 5, 10, and 15 Gy groups at 14 days after irradiation. Conclusion : Clusterin expression was induced by low doses of irradiation and it appeared to be involved in the regulation of cellular response to irradiation.

• Journal of the Korean Society of Food Culture
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• v.15 no.4
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• pp.269-277
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• 2000

A survey was conducted to examine the knowledge and acceptance of food irradiation in order to provide baseline data required in the development of food irradiation education programs for college students. 150 students majoring in food and nutrition or food technology in the Chungnam National University were chosen for a survey. The results are as follows. First, college students' knowledge about food irradiation is scanty. Knowledge assessment showed that 56% of the participants had previously heard of food irradiation. 68% of the respondents thought that radioactivity remains in food after irradiation and 25.3% of them were not sure whether radioactivity remains in food after irradiation or not. Only half of the respondents thought that nutrient loss due to irradiation is equal to or lower than that due to cooking or freezing. Second, approximately 56% of the respondents showed that food irradiation is somewhat or strongly needed for meat or fish; whereas, over 60% of them showed that food irradiation is not needed for grain, vegetable and fruit. Almost 40% of the respondents were seriously concerned about irradiation of vegetables and fruits; whereas, they showed less concern about spice irradiation. More than half of the respondents were not willing to use irradiated food in all the six food groups. Third, the correlation analysis showed that the need of food irradiation is negatively correlated with concerning about the irradiated fish and fruits, but positively correlated with willingness to use irradiated food in all the five food groups, except in spices. Concern about the irradiated food is negatively correlated with willingness to use irradiated food from all the six food groups. Fourth, almost all the respondents (over 90%) agreed that the irradiated food labeling is required as well as the development of proper methods to identify irradiated foods.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.1
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• pp.71-85
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• 1993

The purpose of the study was to investigate the effects of the single and fractionated irradiation on the microvascular structure of the submandibular gland in rats. For this study, 90 Sprague-Dawley strain rats were irradiated to their neck region with equal split doses of 9Gy for a 4 hours interval and 15Gy single dose by 6MV X-irradiation and sacrificed on the 1st, 3rd, 7th, 14th and 27th day after irradiation. The author observed histological changes at Hematoxylin and Eosin staining and PAS staining under a light microscope, and also observed distribution and structural changes of the microvasculature in rat submandibular gland using a scanning electron microscope by forming vascular resin casting. The results were as follows: 1. In the light microscopic examination, the microvasculature was slightly dilated and decreased in number on the 1st day after irradiation, and increase in number of microvasculature was observed on the 3rd day after irradiation. And then distribution of microvasculature was markedly increased on the 7th day after iradiation, but decreased on th 14th day after irradiation again. Such changes were greater in the single irradiated group than in the fractionated irradiated group. 2. The reaction to PAS staining on glandular cell was decreased on the 1st and the 3rd day after irradiation, and recovered on the 7th day after irradiation. The reaction was decreased on the 14th day after irradiation again, and recovered on the 28th day after irradiation. Changes were more apparent in the single irradiated group. 3. In the scanning electron microscopic examination, early changes of microvasculature were decreased capillary density, dilation of conduits and meandering. Increased capillary dentsity or anastomosis due to vascular reproduction and smooth curved running were observed on the 7th and 14th day after irradiation. Decreased capillary and smooth running tendency were observed on the 28th day after irradiation again. Such changes were greater in the single irradiated group than in the fractionated irradiated group.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.1
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• pp.1-8
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• 1999

A single fraction of 50 Gy extracorporeal irradiation, as a modality of limb-sparing operation, has been used to achieve tumor necrosis in osteosarcoma. Although this modality of radiation therapy preserving the mobility of a joint is commonly practiced, the precise knowledge on the radiobiological response of osteosarcoma cell has remained to be elucidated. We therefore observed whether a single high dose irradiation caused apoptosis in osteosarcoma cells and whether the commitment to apoptosis was associated with cell kinetics. We also investigated radiation dose response along the time course for development of apoptosis following single high dose irradiation. The morphologic change in apoptosis was observed by fluorescence with Hoechst 33258 and the degree and the fraction of cells by flow cytometry. Irradiation of osteosarcoma cells with 10, 30 and 50 Gy resulted in chromatin condensation and apoptotic body formation. The degree of apoptosis in osteosarcoma cells was $29.5{\pm}3.56%$, $39.9{\pm}4.83%$ at 24 and 48 hours after 10 Gy irradiation ; $41.1{\pm}3.93%$, $66.9{\pm}5.21%$ at 24 and 48 hours after 30 Gy irradiation ; and $48.0{\pm}3.69%$, $75.6{\pm}4.65%$ at 24 and 48 hours after 50 Gy irradiation. The fraction of cells in cell-cycle kinetic was $39.2{\pm}4.3%$ in G2/M, $22.1{\pm}4.65%$ in G1 at 24 hours after 10 Gy irradiation ; $51.0{\pm}4.3%$ in G2/M, $20.4{\pm}4.7%$ in G1 at 48 hours after 10 Gy irradiation ; $40.3{\pm}3.9%$ in G2/M, $26.1{\pm}4.7%$ in G1 at 24 hours after 30 Gy irradiation ; $59.2{\pm}3.9%$ in G2/M, $5.9{\pm}5.1%$ in G1 at 48 hours after 30 Gy irradiation ; and $44.3{\pm}4.2%$ in G2/M, $21.1{\pm}3.5%$ in G1 at 24 hours after 50 Gy irradiation. The fraction of cells at 48 hours after 50 Gy irradiation could not be observed because of irradiation induced cell death of most of cells. All values for irradiated cells showed accumulation in G2/M phase and reduction in G1 phase, irrespective of irradiation dose. The results suggest that a single fraction of high dose irradiation with 50 Gy results in accumulation of cells at G2/M phase, leading to apoptosis.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.171-182
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• 1990

The purpose of this study was to investigate the effects of irradiation on the striated duct cells of the rat submandibular gland ductal tissues which control the characteristics of saliva. For this study, the experimental group was composed of 36 irradiated Sprague Dawley strain rats divided into 8 subgroups 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours after irradiation. 4 non-irradiated rats were used as the control group. The experimental animals were singly irradiated with a dose of 18Gy gamma ray to their head and neck region by the Co-6- teletherapy unit and sacrificed after each experimental duration. The specimens were examined with a light microscope with an H-E stain and with a trans- mission electron microscope. The results of this study were as follows. In the light micrograph, a severe atrophic change occurred in the striated duct cells at 2hours after irradiation and gradual recovery occurred from 6 hours after irradiation. 2. The nuclear chromosomes of the striated duct cells were changed granular at 2 hours after irradiation. Recovery was observed at 6 hours after irradiation. Nuclear bodies were also observed from 3 hours after irradiation. 3. The mitochondria of the striated duct cells had indistinct cristae at 2 hours after irradiation, and were degenerated or swollen at 3 hours after irradiation. They recovered, however, from 6 hours, with an increasing number at 48 hours and a regular arrangement was observed at 72 hours after irradiation. 4. The microvilli showed atrophic changes at 2 hours after irradiation and were almost lost at 3 hours after irradiation. They were observed again from 48 hours after irradiation. 5. The rough endoplasmic reticulum and golgi body were not apparent at 1 hour after irradiation and were dilated with degeneration 2 hours after, but intact rough endoplasmic reticulum were observed from 3 hours after irradiation and developed well at 24 hours after irradiation. By the result of this study, showing a mild change in the functional morphology of the salivary striated duct cells immediately following irradiation, it is considered that the many complications which occur after radiation therapy, will disappear in time with the histological and the functional recovery of the glandular tissues.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.362-366
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• 2009

To determine the effect of electron-beam irradiation on the contents of polymethoxylated flavones (PMFs) extracts from citrus pomaces (CP), CP was irradiated at 0, 1, 2, or 5 kGy. Methanol extract of the irradiated CP were prepared and the PMF (nobiletin, sinensetin, and tangeretin) content of the extract was determined. Nobiletin and sinensetin of CP extract significantly increased with irradiation dose-dependent. However, electron-beam irradiation decreased the amount of tangeretin in the CP extract. These data suggest that irradiation can liberate phenolic compounds such as nobiletin or sinensetin, but tangeretin might have different pathway of conversion by irradiation. Therefore, irradiation can be a tool to change the composition of PMFs in CP.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.1
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• pp.88-94
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• 1985

Food irradiation is increasingly recognized as the sole viable alternative to traditional method of food preservation in terms of reducing the overall quantity of spoiled food, reducing energy used in food storage, and reducing reliance on chemicals known to be hazardous but currently required for disinfestation. Irradiation with ionizing radiation can be applied in the fields of sprout inhibition, disinfestation of insects, sterilization, delay of ripening, and improvement of organoleptic properties in food. In order to back up the commercialization of food irradiation in Korea, this review not only dealt with the international background for food irradiation and wholesomeness of irradiated food, but also evaluated economic feasibility of irradiated food, irradiation facilities, and domestic status of food irradiation studies.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.758-764
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• 2016

Specimens of stainless steel reactor internals were irradiated with 240 keV protons and 6 MeV Xe ions at room temperature. Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation depth. A different hardening level under H and Xe irradiation was obtained and the discrepancies of displacement damage rate and ion species may be the probable reasons. It was observed that the hardness of Xe-irradiated specimens saturate at about 2 displacement/atom (dpa), whereas in the case of proton irradiation, the saturation hardness may be more than 7 dpa. This discrepancy may be due to the different damage distributions.

• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.45-53
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• 1982

To determine the effect of r-irradiation on the microorganisms destruction and the changes of general constituents of Ginseng Powder, three samples were analyzed at 1st and 3rd month after r-irradiation. The results were as follows: 1. Total bacterial counts were decreased during storage as the irradiation dose increased. It seems that about 300 Krad was satisfactory to the regulation of ginseng powder. ($5.0 \times 10^4 /g$) 2. Coliform group was also decreased during storage as the irradiation dose increased. Coliform group was not detected at the irradiation dose higher than 500 Krad. 3. Total bacterial counts and coilform group were in proportion to the content of moisture in ginseng powder. 4. The contents of moisture, ash, crude protein, crude lipid and total sugar in ginseng powder during storage had nearly no changes. 5. The content of reducing sugar in ginseng powder during storage had the increasing tendencies as the irradiation dose increased. 6. The content of amino-nitrogen in ginseng powder during storage had the decreasing tendencies as the irradiation does increased.