• BMB Reports
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• v.34 no.2
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• pp.123-129
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• 2001

Cellular response to ionizing radiation is affected by cell types, radiation doses, and post-irradiation time. Based on the trypan blue dye exclusion assay in normal oral mucosal cells (OM cells), a 48 h post-irradiation was sufffcient and an adequate time point for the evaluation of radiation sensitivity Its $LD_{50}$ was approximately 1.83 Gy To investigate possible biomarkers useful for the biological radiodosimetry of normal epithelial cells (p53, c-fos, cyclin D1, cdc-2, pRb) EGF receptor phosphorylation and Erk activation were evaluated at different radiation doses and different post-irradiation times. From 0.5 Gy, p53 was accumulated in the nucleus of basal cells of the OM raft culture at 4 h post-irradiation and sustained up to 24 h post-irradiation, which suggests that radiation-induced apoptosis or damage repair was not yet completed. The number of p53 positive cells and biosynthesis of p53 were correlated with radiation doses. Both cyclin D1 and c-fos were only transiently induced within 1 h post-irradiation. Cyclin D1 was induced at all radiation doses. However, cfos induction was highest at 0.1 Gy, approximately 7.3 fold more induction than the control, whose induction was reduced in a reverse correlation with radiation dose. The phosphorylation pattern of cdc-2 and pRb were unaffected by radiation. In contrast to A431 tails overexpressing the EGF receptor approximately 8.5 fold higher than normal epithelial, the OM cells reduced the basal level of the EGF receptor phosphorylation in a radiation dose dependent fashion. In conclusion, among radiation-induced biomolecules, the p53 nuclear accumulation may be considered for the future development of a useful marker far biological radiodosimetry in normal epithelial tissue since it was sustained for a longer period and showed a dose response relationship. Specific c-fos induction at a low dose may also be an important finding in this study It needs to be studied further for the elucidation of its possible connection with the low dose radio-adaptive response.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.1
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• pp.19-27
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• 2022

Background: Myofascial pain dysfunction syndrome (MPDS) is the most common type of temporomandibular disorder. This study compared the efficacies of low-level diode laser therapy (LLLT) and laser acupuncture therapy (LAT) in the treatment of MPDS. Methods: This double-blind randomized controlled clinical trial included 24 patients with MPDS who were randomly divided into two equally sized groups. Patients in the LLLT group received 12 sessions of low-level diode laser irradiation applied to the trigger points of the masticatory muscles during 1 month. The same protocol was also used in the LAT group according to the specific trigger points. We measured pain intensity and maximum mouth opening in both groups at baseline, during treatment, and 2 months after treatment completion. Results: The pain intensities decreased from 6.58±1.31 to 0.33±0.65 and from 7.08 ± 1.37 to 0 in the LLLT and LAT groups, respectively. The maximum mouth openings increased from 32.25 ± 8.78 mm to 42.58 ± 4.75 mm and from 33 ± 6.57 mm to 45.67 ± 3.86 mm in the LLLT and LAT groups, respectively. Pain intensity (P = 0.839) and level of maximum mouth opening (P = 0.790) did not differ significantly between the groups. Conclusion: Our results showed similar efficacy between LLLT and LAT in the treatment of MPDS signs and symptoms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.347-348
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• 2006

This paper performed the basic study for developing the Photodynamic Therapy Equipment for medical treatment. The equipment have been manufactured by using the High Bright Light Emitting Diode and TLC5941 integrated circuit. As a result, 630nm Light Emitting Diode Module was made for the optimization of irradiation condition. And we confirmed the current change according to increase of the level of Light Emitting Diode Module.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.6
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• pp.1-7
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• 2015

Most of chloride diffusion models based on finite difference method (FDM) could not express the diffusion in horizontal direction at each elevation. To overcome these weakness, two dimensional chloride ion penetration model based on finite element method (FEM) to be able to combine various multi-physics simultaneously was suggested by introducing moving mesh technique. To avoid the generation of mesh being able to be distorted depending on the relative movement of water level to static concrete, a rectangular type of mesh was intentionally adopted and the total number of meshes was empirically selected. The simulated results showed that the contents of surface chloride decreased following to the increase of elevation in the top part of low sea level, whereas there were no changes in the bottom part of low level. In the DuraCrete model, the diffusion coefficient of splashed zone is generally smaller than submerged zone, whereas the trend of Life365 model is reverse. Therefore, it could be understood that the developed model using moving mesh technique effectively reflects $DuraCrete^{TM}$ model rather than $Life365^{TM}$ model. In the future, the model will be easily expanded to be combined with various multi-physics models considering water evaporation, heat of hydration, irradiation effect of sun and so on because it is based on FEM.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.185-189
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• 1987

The number of splenic lymphocyte, serum prostaglandin $E_2$ level and natural killer cell activity were assayed after single whole body irradiation of a sublethal dose of $^{60}Co-{\gamma}$ ray to C57BL/6J mice. With a view to knowing the relationships between radiation induced prostaglandin $E_2$ level and the normal natural killer cell activity after natural killer cell-target cell conjugation, The change of normal natural killer cell activity were measured by administration of prostaglandin $E_2$ containing serum from irradiated mice. The results were summarized as follows; 1. The total number of splenic lymphocyte was significantly decreased by irradiation and the number was not affected by indometacin, prostaglandin synthesis inhibitor, treatment. 2. Serum prostaglandin $E_2$ level was increased in irradiated mice, but indometacin treated mice group showed low level of prostaglandin $E_2$. 3. In the case of irradiated mice, natural killer cell activity was not shown any difference between irradiated group and indometacin combined group. But when natural killer cell-target cell conjugations were exposed to the serum of each group during cytotoxic activity assay, whereas the normal natural killer cell activity was significantly decreased by treatment of serum from irradiated mice, the activity was not changed by treatment of indometacin pretreated mice serum. This result indicated that the prostaglandin $E_2$ induced by the radiation inhibited the post-target binding cytolytic process of natural killer activity.

• Nuclear Engineering and Technology
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• v.13 no.3
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• pp.161-167
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• 1981

For determination of mutation frequency induced by chronic irradiation of low dose gamma rays, Tradescarrfia clone 4430 was exposed to Co-60 ${\gamma}$ rays with different exposure rates from 3.6mR/day to 182R/day in or out of the Gamma Field at Kumkok Experiment Farm of KAERI. Somatic mutations based on pink mutant events of the stamen hair cells were clearly observed by the treatment. The pink mutant events were increased proportionally with increasing exposure rates of gamma ray except for relatively high dose rates of 105 R/day and 182 R/day, indicating saturation effect of mutation. The somatic pink mutations could be fairly detectable even in the low dose rate of 3.6mR/day. Therefore, this stamen hair system of Tradescantia clone 4430 seemed to be an reasonable test system for detecting mutability of low level irradiation. These results imply that artificial mutation induction in the fruit and ornamental trees could be expected in the ${\gamma}$-field.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.474-481
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• 1985

Radurization effects on fried fish meat paste with Co-60 gamma irradiation at 0-5 kGy and physicochemical aspects of the stored samples at low ($3{\pm}1^{\circ}C$, LT) and room ($10-20^{\circ}C$, RT) temperatures were investigated. The initial microbial loads of the samples were $2.2{\times}10^3/g$ in total bacterial count, $2.8{\times}10^2/g$ in yeasts & molds, and $1.0{\times}10^2/g$ in coliform group, respectively. An irradiation dose of more than 3 kGy was shown to be effective for the radurization of stored samples and there is no apparent difference between air and vacuum packaging groups. The chemical components related to the quality underwent similar changes in the nonirradiated and irradiated groups; however, as the storage time was prolonged the quality of nonirradiated samples rapidly deteriorated. Textural parameters of the samples were little affected by the applied doses, and sensory evaluations showed that 3 kGy irradiation was the optimum dose level to extend the shelf-life of fried fish meat paste up to 2 times at RT and 3 to 4 times at LT, respectively compared with the nonirradiated control.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.120-124
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• 2009

The concept of biostimulation of wounds by low-level laser therapy(LLLT) is attracting considerable attention. Although its effect on whole tissues has been studied quite extensively, the biological and cellular mechanisms underlying LLLT have not been clarified. In an experimental radius fracture in rabbits, Tang and Chai reported that LLLT enhanced the activity of red blood cells, macrophages, fibroblasts, chondrocytes, and osteoclasts within the fracture area. The purpose of the present study was to evaluate the effect of LLLT with a GaAlAs diode laser device on bone healing in rabbit mandibular fractures. We use 12 rabbits for this study. All rabbits were fractured mandible angle area using saw in anesthetic condition. In control group(n=6), none treatment was performed at fracture site. In experimental group(n=6), LLLT with a GaAlAs diode laser was radiated at fracture site daily for 7 days. All rabbits were sacrificed at 6 weeks later from performed fracture day. We studied the immunohistochemical staining of CD34 and Vimentin and the histochemical analysis for calcium and phosphorus content. The results were as follows. 1. In the histological and immunohistological staining, after 6week, fibroblasts, osteogenic cells and collgen fibers were observed more in experimental group than in control group. 2. In the histochemical analysis, the amount of calcium and phosphorus contents of the experimental group were more than the control group. From the results obtained, we suggest that the bone healing is stimulated by low-level laser irradiation in bone fractures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.6
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• pp.259-268
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• 2018

Objectives: The purpose of this study was to evaluate the synergic effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) and low-level laser therapy (LLLT) on bisphosphonate-treated osteoblasts. Materials and Methods: Human fetal osteoblast cells (hFOB 1.19) were cultured with $100{\mu}M$ alendronate. Low-level Ga-Al-As laser alone or with 100 ng/mL rhBMP-2 was then applied. Cell viability was measured with MTT assay. The expression levels of receptor activator of nuclear factor kappa-B ligand (RANKL), macrophage colony-stimulating factor (M-CSF), and osteoprotegerin (OPG) were analyzed for osteoblastic activity inducing osteoclastic activity. Collagen type and transforming growth factor beta-1 were also evaluated for bone matrix formation. Results: The results showed that rhBMP-2 and LLLT had a synergic effect on alendronate-treated osteoblasts for enhancing osteoblastic activity and bone matrix formation. Between rhBMP-2 and LLLT, rhBMP-2 exhibited a greater effect, but did not show a significant difference. Conclusion: rhBMP-2 and LLLT have synergic effects on bisphosphonate-treated osteoblasts through enhancement of osteoblastic activity and bone formation activity.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.58-65
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• 2008

To see the possibility of irradiation as an alternative to ultra high temperature (UHT) sterilization, the quality characteristics of milk were analyzed. Milk treated by UHT ($135^{\circ}C$ for 4 sec) and irradiation at higher than 3 kGy showed no viable counts after 7 days of storage at $4^{\circ}C$. The contents of certain amino acids of milk, such as Arg, Asp, Glu, Ile, Leu, Lys, Pro, Ser, Thr, and Tyr, were lower in irradiated groups at 10 kGy than in UHT-treated one, but no difference was observed between irradiated milks at less than 5 kGy and UHT. The capillary electrophoresis (CE) patterns of the milk irradiated at 10 kGy showed a similar trend to the raw milk, low temperature long time (LTLT, $63^{\circ}C$ for 30 min), and high temperature short time (HTST, $72^{\circ}C$ for 15 sec) treated. However, the CE pattern of UHT-treated milk was different. Rennet coagulation test agreed with the CE results, showing that all milk samples were coagulated by rennet addition except for UHT-treated milk after 1 hr. These results suggest that irradiation of milk reduce the content of individual amino acids but it may not induce severe conformational change at a protein level when compared with UHT treatment.