• Radiation Oncology Journal
• /
• v.17 no.3
• /
• pp.230-237
• /
• 1999

Purpose : To elucidate the effects of pentoxifylline and diltiazem on the late response of the salivary glands of the rat after irradiation. Materials and Methods : Sixteen Sprague-Dawley rats were divided into 4 groups : (a) irradiation alone (b) irradiation with pentixifylline (PTX) (c) irradiation with diltiazem (DTZ) (d) irradiation with both PTX and DTZ. Irradiation was given in a single fraction of 16 Gy using 4 MV photon energy through an anterior port encompassing the left side of the salivary gland leaving the right side of salivary gland as a control. PTX, 20 mg/kg and/or DTZ, 50 mg/kg were infused intraperitoneally before irradiation, Two rats from each group were sacrificed on the 10th week and the rest was sacrificed on the 16th week after irradiation. Histopathologic examinations were undertaken for each section and the proportion of vacuolated cells out of the total number of cells under light microscopic fields was calculated. The statistical significance in the difference of the proportion of the vacuolated cells among the experimental groups was evaluated by a $x^2$-test. Results : Irradiated salivary glands of the 10th week group revealed markedly increased number of vacuolated cells compared to those of unirradiated control. The proportion of vacuolated cells was significantly reduced in both the PTX group (p value=0.001) and the combined PTX and DTX group compared to those of irradiation alone group. The DTZ alone group did not reveal the significant reduction of vacuolated cells compared to those of irradiation alone group (p value, >0.05). The 16th week groups revealed similar findings to those of the 10th week group, but the degree of chronic inflammatory cell infiltrates and interstitial fibrosis was increased and the number of acinar cells was reduced compared to those of the 10th week group. Conclusions : PTX significantly reduced the late radiation response of salivary glands, but DTZ did not reduce the same degree as PTX did. Taking the positive results of this study into consideration, it seems reasonable to apply PTX into the clinical trial for the head and neck irradiation to reduce the late radiation sequelae of salivary glands in the near future. At the same time the further experiment to clarify the subcellar mechni는 involved in PTX should be preceded.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.27 no.1
• /
• pp.43-53
• /
• 1997

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. For this study, cell surviving curves were obtained for mouse lymphoma YAC-1 cell line using semi automated MTT assay. 2, 4,6, 8, 10Gy were irradiated at a dose rate of 210cGy/rnin using /sup 60/Co Irradiator ALDORADO 8. After irradiation, YAC-1 cell lines(3×10⁴cells/ml) were exposed to bleomycin or cisplatin for 1 hour. The viable cells were determined for each radiation dose and/or each concentration of drug at the 4th day. And they were compared to control values. The obtained results were as follows : 1. The surviving curve with gentle slope was obtained after irradiation of 2, 4, 6, 8, 10 Gy on YAC-1 cell line. 2. The cytotoxicity of bleomycin or cisplatin was increased significantly at all concentration of 0.2㎍/ml, 2㎍/ml and 20㎍/ml on YAC-1 cell line (P<0.01). And the cytotoxicity of cisplatin was greater than that of bleomycin at all concentration on YAC-1 cell line (P<0.01). 3. There were no significant differences of surviving fractions among 4Gy, 6Gy and 8Gy after irradiation of each radiation dose with 2㎍/ml of bleomycin compared with irradiation only on YAC-1 cell line. 4. There was significant difference of surviving fraction between 2Gy and 10Gy after irradiation of each radiation dose with 2㎍/ml of cisplatin compared with irradiation only on YAC-1 cell line(P<0.05). 5. There were significant differences of surviving fractions between the groups of irradiation only and the groups of irradiation with 2㎍/ml of bleomycin or cisplatin at all doses of 2, 4, 6, 8 and 10Gy on YAC-1 cell line(P<0.05).

• Journal of Korean Neurosurgical Society
• /
• v.37 no.5
• /
• pp.370-374
• /
• 2005

Objective: We investigated the morphologic changes within 24 hours after a single ${\gamma}$-irradiation in the rat brain. Methods: Forty Sprague-Dawley rats were used. After a burr hole trephination on right parietal area, cerebral hemisphere was irradiated with 2Gy and 5Gy using iridium-192($^{192}Ir$), respectively. The effect was assessed at 4, 8, 12 and 24 hours after irradiation. The histological changes were scored following the detection of edema or disarray severity. TUNEL-positive cells exhibiting apoptotic morphology were counted in irradiated region. Results: Cortical edema and disarray were initially showed at 4 or 8 hour and almost all defined at 24 hour after irradiation. And the injury was wedge shape. TUNEL-positive cells were minimal at 8 hour after irradiation as the number of positive cells were $2.6{\pm}5.27$(n=5) after 2Gy, and $0.8{\pm}0.84$(n=5) after 5Gy. But, the number of apoptotic cells were increased markedly to $60{\pm}6.24$ at 12 hour after 2Gy and to $104{\pm}19.7$ at 24 hour after 5Gy. Conclusion: There were prominent morphologic changes immediately after ${\gamma}$-irradiation. And, apoptosis was increased according to the time period. These findings implicate that brain irradiation induces rapid apoptotic change, which may play an important role in the pathogenesis of radiation-induced pathologic conditions.

• Radiation Oncology Journal
• /
• v.19 no.2
• /
• pp.146-152
• /
• 2001

Purpose : To investigate the regulation of apoptosis and cell cycle in mouse brain irradiation. Materials and Methods : 8-week old male mice, C57B1/6J were given whole body $\gamma-radiation$ with a single dose of 25 Gy using Cobalt 60 irradiator. At different times 1, 2, 4, 8 and 24hr after irradiation, mice were killed and brain tissues were collected. Apoptotic cells were scored by TUNEL assay. Expression of p53, Bcl-2, and Bax and cell cycle regulating molecules; cyclins Bl, Dl, E and cdk2, cdk4, $p34^{cdc2}$ were analysed by Western blotting. Cell cycle was analysed by Flow cytometry. Results : The peak of radiation induced apoptosis is shown at 8 hour after radiation. With a single 25 Gy irradiation, the peak of apoptotic index in C57B1/6J is $24.0{\pm}0.25$ (p<0.05) at 8 hour after radiation. Radiation upregulated the expression of p53/tubulin, Bax/tubulin, and Bcl-2/tubulin with 1.3, 1.1 and 1.45 fold increase, respectively were shown at the peak level at 8 hour after radiation. The levels of cell cycle regulating molecules after radiation are not changed significantly except cyclin D1 with 1.3 fold increase. Fractions of Go-Gl, G2-M and S phase in the cell cycle does not specific changes by time. Conclusion : In mouse brain tissue, radiation induced apoptosis is particularly shown in a specific area, subependyma. These results and lack of radiation induced changes in cell cycle ofter better understanding of radiation response of noraml brain tissue.

• Journal of IKEEE
• /
• v.15 no.2
• /
• pp.143-148
• /
• 2011

MOS (Metal-Oxide Semconductor) devices among the most sensistive of all semiconductors to radiation, in particular ionizing radiation, showing much change even after a relatively low dose. The necessity of a radiation dosimeter robust enough for the working environment has increased in the fields of aerospace, radio-therapy, atomic power plant facilities, and other places where radiation exists. The power MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) has been tested for use as a gamma radiation dosimeter by measuring the variation of threshold voltage based on the quantity of dose, and a maximum total dose of 30 krad exposed to a $^{60}Co$ ${\gamma}$-radiation source, which is sensitive to environment parameters such as temperature. The gate oxide structures give the main influence on the changes in the electrical characteristics affected by irradiation. The variation of threshold voltage on the operating temperature has caused errors, and needs calibration. These effects can be overcome by adjusting gate oxide thickness and implanting impurity at the surface of well region in MOSFET.

• ETRI Journal
• /
• v.27 no.4
• /
• pp.449-452
• /
• 2005

The electrical characteristics of solid state devices such as the bipolar junction transistor (BJT), metal-oxide semiconductor field-effect transistor (MOSFET), and other active devices are altered by impinging photon radiation and temperature in the space environment. In this paper, the threshold voltage, the breakdown voltage, and the on-resistance for two kinds of MOSFETs (200 V and 100 V of $V_{DSS}$) are tested for ${\gamma}-irradiation$ and compared with the electrical specifications under the pre- and post-irradiation low dose rates of 4.97 and 9.55 rad/s as well as at a maximum total dose of 30 krad. In our experiment, the ${\gamma}-radiation$ facility using a low dose, available at Korea Atomic Energy Research Institute (KAERI), has been applied on two commercially available International Rectifier (IR) products, IRFP250 and IRF540.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.307.1-307.1
• /
• 2002

Inflammation is a frequent radiation-induced following therapeutic irradiation. Since the upregulation of adhesion molecules on endothelial cell surface has been known to be associated with inflammation. interfering with the expression of adhesion molecules is an important therapeutic target. We examined the effect of allicin. a major component of garlic. on the induction of intercellular adhesion molecule-1 (lCAM-1) by gamma-irradiation and the mechanisms of its effect in gamma-irradiated human umbilical vein endothelial cells (HUVECs). (omitted)

• Korean Journal of Food Science and Technology
• /
• v.49 no.5
• /
• pp.544-549
• /
• 2017

The spent coffee grounds (SCG) are considered valuable by-products because they contain various bioactive compounds. The SCG extraction (SCGE) was irradiated at doses ranging between 30 and 50 kGy. The deep dark-brown color of SCGE was changed to a bright yellow color by gamma irradiation. The content of the bioactive compounds of gamma-irradiated SCGE was analyzed by high-performance liquid chromatography. Interestingly, the content of quinic acid was increased by gamma irradiation, whereas other compounds were decreased. Although the contents of bioactive compounds were changed by gamma irradiation, the biological activities (radical scavenging activity and whitening effects) of SCGE were unaffected. Our findings suggest that gamma irradiation can effectively improve the color values of SCGE without the loss of biological activities. Consequently, gamma irradiation can be a useful tool for improving the utilization of SCGE in the cosmetic industry.

• Journal of Radiation Protection and Research
• /
• v.29 no.4
• /
• pp.237-242
• /
• 2004

The radioprotective effects of Melatonin and Ge-132 on acute hematopoietic injury was investigated in mice exposed to an acute whole-body radiation dose of 8 Gy. Melatonin was administered intraperitoneally 1 hour before irradiation at a dose of 200 mg/kg, and Ge-132 was administered orally from days 5 to 20 after irradiation at a dose 130 - 150 mg/kg/d. The radioprotective effects were evaluated for spleen using TUNEL assay, and in peripheral blood by counting lymphocyte & WBC. The 4 experimental groups (irradiation-only, melatonin pretreatment, Ge-132 posttreatment, and melatonin pretreatment plus Ge-132 posttreatment) were observed for survival analysis up to 30 days following irradiation. The apoptotic index (47.8% vs 45.9%, p=0.385), and the number of lymphocytes ($97/{\mu}{\ell}\;vs\;101/{\mu}{\ell}$, p=0.898) were not significantly different between the irradiation-only and the melatonin pretreatment group, But the number of WBCs ($147/{\mu}{\ell}\;vs\;306/{\mu}{\ell}$, p=0.010) was higher in the melatonin pretreatment group. The irradiation-only, melatonin, Ge-132, and melatonin plus Ge-132 treatments resulted in survival rate at 30 days of 21.4%, 100%, 35.7%, and 85.7%, respectively. The melatonin pretreatment group in survival analysis between groups was showed significantly higher survival than the irradiation-only(p=0.000), or Ge-132 posttreatment group(p=0.0003). These results indicate that the melatonin may have a potential as an effective radioprotector on acute hematopoietic syndrome following radiation exposure.

• Food Science and Preservation
• /
• v.12 no.1
• /
• pp.28-35
• /
• 2005

The storage temperature significantly affected the microbiological quality of the chicken breast In the non-inadiated samples at $30^{\circ}C$, aerobic plate count (APC) and Echerichia coli count of the samples considerably increased during 3 days of storage and were eliminated by an irradiation at dose of 10 kGy or more. The APC and E coli count of the samples stored at $5^{\circ}C$ were reduced to below the limit of detection (< 2 log CFU/g) through the whole storage period by an irradiation at 5 kGy or mote. There was no significant difference in the TBA values between the non-inadiated and inadiated samples, which were not significantly higher in the irradiated samples than the non-inadiated samples during 2 weeks of storage at $5^{\circ}C$. According to the same-different test and acceptance test the sensory quality of the irradiated chicken breast was not significantly different from that of the non-inadiated sample even at 10 kGy. It is found that gamma irradiation is an effective tool to improve the quality of chicken breast in a group-meal service. It was also found that there was no evidence that an irradiation induced mutagenicity in the chicken breast meat.