• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.435-449
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• 1999

Purpose : The study was aimed to detect the differences in the cell viability and the apoptosis induction after irradiation on normal and tumorigenic cells. Materials and Methods : The study. that was generated for two human normal cells(RHEK, HGF-l) and two human tumor cells(KB. HT-1080). was tested using MTT assay at 1 day and 3 day after irradiation and TUNEL assay under confocal laser scanning microscope at 1 day after irradiation. Single irradiation of 0.5. 1, 2. 4. and 8Gy were applied to the cells. The two fractions of 1. 2. 4. and 8Gy were separated with a 4-hour time interval. The irradiation was done with 5.38Gy/min dose rate using Cs-137 irradiator at room temperature. Results and Conclusions : 1. In 3-day group. the cell viability of HGF-1 cell was significantly decreased at 2. 4 and 8Gy irradiation, the cell viability of KB cell was significantly decreased at 8Gy irradiation and the cell viability of HT-I080 cell was significantly decreased at 4 and 8Gy irradiation. 2. There was significant difference between RHEK and KB cell line in the cell viability of 3-day group at 8Gy irradiation. There was significant difference between RHEK and HGF-1 cell line in the cell viability of 3-day group at 4 and 8Gy irradiation. 3. There was a significantly decreased cell viability in 3-day group than those in 1-day group at 2. 4 and 8Gy on HGF-1 cell. at 4 and 8Gy on HT-I080 cell. at 8Gy on KB cell. 4. We could detect DNA fragmented cells only on KB cell. Number of apoptotic cells of KB cell was significantly increased at 4 and 8Gy irradiation. However, there was no correlation between cell viability and apoptosis. 5. On all 4 cell lines, there were no differences between single and split irradiation method in cell viability and apoptosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.617-624
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• 2007

Insulin-like growth factor(IGF) is the most abundant growth factor in bone matrix. Recent studies have shown that it can sensitize apoptotic cell death of osteoblasts. Thus, this study investigated whether IGF-II aggravates irradiation-induced cell death of osteoblasts. Cultured MC3T3 osteoblasts were irradiated and IGF-II was added at the concentration of 50 ng/ml immediately after the irradiation. Cell viability was measured by MTT assay. Changes in cell death and cell cycle were analyzed by flow cytometry. The expression of proapoptotic gene bax and antiapoptotic gene bcl-2 was quantified by real time RT-PCR and Western blot. A dose of 30 Gy caused G2/M arrest and increased cell death through both necrosis and apoptosis, while irradiation from 4 to 10 Gy little affected cell cycle and death. IGF-II treatment reduced cell viability without stimulating cell proliferation and changing cell cycle. Combined treatment of IGF-II with irradiation decreased cell viability and proliferation and increased cell death along with G2/M arrest. These effects were not different from those of irradiation only. At transcriptional and protein levels, IGF-II treatment did not affect bax and bcl-2 expression, whereas irradiation increased the expression ofbax without changes in bcl-2. IGF-II in combination with irradiation showed similar findings. These results suggest that IGF-II could modulate apoptotic cell death through mechanisms other than an imbalance between bax and bcl-2 gene expression, although its effect was overridden by irradiation.

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.71-79
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• 2000

Purpose : This study was aimed to evaluate the cell cycle arrest and apoptosis induction after irradiation and epidermal growth factor (EGF) treatment in three human epithelial tumor cell lines (A431, Siha, KB). Materials and Methods: Single irradiation of 2, 5 and 10 Gy was done on three cell lines with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. Also, EGF of 10 ng/ml was added immediately after 10 Gy irradiation. Cell growth was evaluated by counting the living cell number using a hemocytometer at 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Cell cycle arrest and apoptosis induction were assayed with the flow cytometry at 8 hours, 12 hours, 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Results : Growth of irradiated three cell lines were inhibited in proportion to radiation dose. EGF treatment after irradiation showed various results according to cell lines. On all cell lines, G2 arrest was detected after 8 hours and maximized after 12 hours or 1 day. Amount of G2 arrest was positively dose dependent. However, EGF showed no significant change on G2 arrest. G2 arrest was recovered with time at 2 Gy and 5 Gy irradiation. However, at 10 Gy irradiation, G2 arrest was continued. Apoptosis was detected at 10 Gy irradiation. On EGF treated group after irradiation, A431 and Siha cell lines showed slightly increased apoptosis but there was no statistically significant difference. KB cell line showed no marked change of apoptosis induction. Conclusion : Irradiation effects on cell cycle arrest and apoptosis induction in three human epithelial tumor cell lines, however epidermal growth factor doesn't effect on.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.8
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• pp.760-765
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• 2008

Low power laser therapy is internationally certified and is known to be effective in stimulating DNA in living organisms, increasing protein synthesis and activating cell division, smoothing blood circulation, promoting cell activation, cell regeneration and function. It also has anti-inflammatory, anti-edemic, anti-fibrous dysplastic and neuralogic hyperfunctional effects. This study was intended to verify the effect of LED irradiation therapy on wound healing in cell and animal tests by applying LED irradiator using a laser and laser diode, which was independently designed and developed to emit beams of similar wavelength to that of a laser. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity and reservation. In case of cell proliferation experiment, each experiment was performed to irradiation group and non-irradiation group for tissue cells. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590 nm transmittance of micro-plate reader. In the wound healing experiment, 1$cm^2$ wounds on the skin wound of SD-Rat(Sprague-Dawley Rat) were made. Light irradiation group and none light irradiation group divided, each group was irradiated one hour a day for 9 days. As a result, the cell increase of tissue cells was verified in irradiation group as compared to non-irradiation group. And, compared with none light irradiation group, the lower incidence of inflammation and faster recovery was shown in light irradiation group.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04b
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• pp.10-11
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• 2008

We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 levels by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage. And then, each experiment was performed to irradiation group and non-irradiation group for bone marrow cells. MIT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of bone marrow cells was verified in irradiation group as compared to non-irradiation group.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.514-515
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• 2008

Low level laser therapy has various therapy effects. This paper performed the basic study for developing the Low Level Laser Therapy Equipment for medical treatment. The apparatus has been fabricated using the laser diode and microprocessor unit. This equipment was fabricated using a micro-controller and a laser diode, and designed to enable us to control light time, frequency and so on. In this study, the designed device was used irradiation to find out how 850 nm laser diode affected the cell proliferation of RAT bone-marrow cells. Experiment was performed to irradiation group and non-irradiation group for Rat bone marrow cells. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590 nm transmittance of micro plate reader. As a result, the cell increase of Rat bone marrow cells was verified in irradiation group as compared to non-irradiation group. The fact that specific wavelength irradiation has an effect on cell vitality and proliferation is known through this study.

• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.15-24
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• 2009

The effect of low doses of ultraviolet (UV) irradiation on morphology changes of cell has been studied based on the observation of the cell length. It was shown that UV-irradiated cell has different behavior in comparison with non-irradiated cell. From the histogram of cell-length distribution, it was confirmed that cell cycle of non irradiated cell was 28 hours, and that cell cycle of irradiated cell with dose of $20\;Jm^{-2}$ was delayed (39 hours), while irradiated cell with $40\;Jm^{-2}$ and $60\;Jm^{-2}$ did not divide and kept growing continuously. It was supposed that in case of $20\;Jm^{-2}$ of irradiation dose, the cell cycle was delayed because the checkpoint worked in order to repair DNA damage induced by generation of pyrimidine dimer, reactive oxygen species and so on. It was also supposed that in case of $40\;Jm^{-2}$ and $60\;Jm^{-2}$ of irradiation dose, overgrowth was induced because the checkpoint was not worked well. The morphology of overgrown cell was similar to that of normally senescent cell. Therefore, it was considered that cell senescence was accelerated by UV irradiation with irradiation doses of $40\;Jm^{-2}$ and $60\;Jm^{-2}$.

• Analytical Science and Technology
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• v.27 no.1
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• pp.27-33
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• 2014

This study described about preparation of the cross-linked silk fibroin (SF) film by ${\gamma}$-irradiation of the casted SF film, which is fabricated from aqueous solution regenerated via fibers of cocoons and their application as supports for human cell culture. The properties of cross-linked SF film were evaluated by FT-IR spectroscopy, contact angle, solubility to water, thermal analysis, surface area analyzer, and morphology via scanning electron microscopy (SEM). The cross-linked SF films were not dissolved in water and exhibited the rough surface morphology, large surface area, and good thermal properties. The human fibroblast cell (CCD-986sk) and embryo kidney-ft cell were well growed on the surface of cross-linked SF film supports prepared by ${\gamma}$-irradiation. The cross-linked SF film prepared by ${\gamma}$-irradiation can be used as biomaterials for human cell culture.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.43-53
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• 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 Academy of Oral and Maxillofacial Radiology
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• v.27 no.2
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• pp.91-103
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• 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 human epidermoid carcinoma A-253 cell line using semiautomated MTT assay. 2,4,6,8,10 Gy were irradiated at a dose rate of 210 cGy/min using /sup 60/Co Irradiator ALDORADO 8. After irradiation, A-253 cell lines(2×10⁴cells/mil were exposed to bleomycin or cisplatin for 1 hour. The viable cells were determined for each radiation dose with/without 2 /lg/mi of drug at the 3rd day. And they were compared to control values. The results were obtained as follows : 1. The surviving curve with gentle slope was obtained after irradiation of 2, 4, 6, 8, 10 Gy on A-253 cell line. 2. The cytotoxicity of bleomycin or cisplatin at the concentration of 2㎍/ml was great on A-253 cell line. But, there was no significant difference between the cytotoxicity of bleomycin and that of cisplatin. 3. There were significant differences of surviving fractions after irradiation with 2㎍/mi of bleomycin compared with irradiation only on A-253 cell line. 4. There were significant differences of surviving fractions after irradiation with 2㎍/ml of cisplatin compared with irradiation only on A-253 cell line. 5. There were no significant differences of surviving fractions between the groups of irradiation with bleomycin and the groups of irradiation with cisplatin on A-253 cell line.