• Archives of Plastic Surgery
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• v.45 no.5
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• pp.403-410
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• 2018

Background Radiation-induced skin injury is a dose-limiting complication of radiotherapy. To investigate this problem and to develop a framework for making decisions on treatment and dose prescription, a murine model of radiation-induced skin injury was developed. Methods The dorsal skin of the mice was isolated, and irradiation was applied at single doses of 15, 30, and 50 Gy. The mice were followed for 12 weeks with serial photography and laser Doppler analysis. Sequential skin biopsy samples were obtained and subjected to a histological analysis, immunostaining against transforming growth factor beta (TGF-${\beta}$), and Western blotting with Wnt-3 and ${\beta}$-catenin. Increases in the levels of TGF-${\beta}$, Wnt, and ${\beta}$-catenin were detected after irradiation. Results All tested radiation doses caused progressive dermal thickening and fibrosis. The cause of this process, however, may not be radiation alone, as the natural course of wound healing may elicit a similar response. The latent appearance of molecular and histological markers that induce fibrosis in the 15 Gy group without causing apparent gross skin injuries indicates that 15 Gy is an appropriate dose for characterizing the effects of chronic irradiation alone. Thus, this model best mimics the patterns of injury that occur in human subjects. Conclusions This animal model can be used to elucidate the gross and molecular changes that occur in radiation-induced skin injury and provides an effective platform for studying this adverse effect without complicating the process of wound healing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.240-240
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• 2009

We developed the low level laser therapy(LLLT) apparatus for external injury cure using a GaAsP Diode. This equipment was fabricated by using GaAsP diode and a microcontroller, and designed to enable us to control light irradiation timer, and frequency. In this paper, the designed device was used to find out how GaAsP diode light source affects the skin wound of RAT. In the experiment, $1cm^2$ wounds on the External injury of RAT were made. Light irradiation RAT and none light irradiation RAT divided, each RAT was irradiated 20 min a day for 9 days. In result, compared with none light irradiation RAT, the lower incidence of inflammation and faster recovery was shown in light irradiation RAT.

• Biomolecules & Therapeutics
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• v.24 no.3
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• pp.305-311
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• 2016

Mitochondria-targeted vitamin E (MVE) is designed to accumulate within mitochondria and is applied to decrease mitochondrial oxidative damage. However, the protective effects of MVE in skin cells have not been identified. We investigated the protective effect of MVE against UVB in dermal fibroblasts and immortalized human keratinocyte cell line (HaCaT). In addition, we studied the wound-healing effect of MVE in animal models. We found that MVE increased the proliferation and survival of fibroblasts at low concentration (i.e., nM ranges). In addition, MVE increased collagen production and downregulated matrix metalloproteinase1. MVE also increased the proliferation and survival of HaCaT cells. UVB increased reactive oxygen species (ROS) production in fibroblasts and HaCaT cells, while MVE decreased ROS production at low concentration. In an animal experiment, MVE accelerated wound healing from laser-induced skin damage. These results collectively suggest that low dose MVE protects skin from UVB irradiation. Therefore, MVE can be developed as a cosmetic raw material.

• Korean Journal of Veterinary Research
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• v.37 no.3
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• pp.629-637
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• 1997

This study was performed to determine the optimal dose of laser energy for wound healing. The skin wound with 8mm diameter was induced over the lumbar vertebrae of the rats, and wound squares, scab hardness, hematologic findings and histopathlogic findings according to irradiation of laser energy were studied. 1. Wound square was significantly reduced at Day 1 (p<0.01), 2 (p<0.01), 3 (p<0.05), 7 (p<0.01) and 8 (p<0.05), respectively in experimental groups, especially group II, compared with control group. 2. Scab hardness was significantly increased at Day 1 (p<0.01), 2 (p<0.01), 3 (p<0.05), 5 (p<0.01) and 7 (p<0.01), respectively in experimental groups, especially group II, compared with control group. 3. In hematological findings, red blood cells and white blood cells in experimental group were increased according to the lapse of days, but they were not significant. 4. In histopathologic findings, experimental groups, especially group II, revealed early scab formation, early appearance of phagocytes and fibroblast, rapid growth of granulation tissue and collagen, and promotion of wound healing in the result.

• Current Optics and Photonics
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• v.6 no.3
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• pp.227-235
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• 2022

To investigate the aging-related physiological functions of organic light-emitting diodes (OLEDs), we examined mRNA expression changes in aging-related genes due to oxidative stress inhibition by 630-nm red light OLEDs. As a result of irradiating 630-nm OLED with an intensity of 5 mW/cm² for 15 min, the viability of dermal fibroblasts significantly increased by 1.3-fold. In addition, reactive oxygen species generated by H₂O₂ were significantly reduced about 4.9-fold by irradiation with 630-nm OLED. Quantitative reverse-transcription polymerase chain reaction results showed that 630-nm OLEDs altered aging-related gene mRNA expression levels through antioxidant activity. The mRNA expression levels of matrix metalloproteinase1 (MMP1) and MMP9 decreased significantly, by about 2.2- and 2.5-fold, compared to the control group, whereas those of collagen, type I, and alpha 1 increased significantly, by 4.9-fold. The mRNA expression levels of cancer suppression genes p16 and p53 in dermal fibroblasts were also significantly reduced by 630-nm OLED irradiation, by about 1.4- and three-fold, respectively, compared to the control. Overall, it was confirmed that 630-nm OLED irradiation lowered the level of ROS formation induced by H₂O₂ in dermal fibroblasts, and that this antioxidant effect could regulate the mRNA expression levels of aging- and tumor suppression-related genes. This study shows a link between 630-nm OLED irradiation and anti-aging physiological functions such as antioxidant function, and suggests the potential of OLEDs as a useful light source for skin care.

• The Korean Journal of Pain
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• v.7 no.1
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• pp.74-77
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• 1994

Since its introduction, low level lasers have been utilized in many varied clinical applications for the treatment of musculoskeletal and body surface lesions. Due to the laser beams specific characteristic-coherence, monochromaticity and unidirectionality, without adverse reaction with neighbouring tissue, physicians have used it with relative ease. We observed accelerating effects of healing process of some intractable skin wound, improvement of graft survival, as well as reduction of pain on ulcerating tissues, by treating twice weekly with low level Helium-Neon(He-Ne) and Infrared(IR) laser. The laser's energy density was set at $1\;J/cm^2$ and a fixed frequency of 600 Hz by continuous scanning. Irradiating time was calculated according to the cross diameter of the wound. Further clinical work will be required to evaluate the accelerated healing processes by biostimulating mechanisms of laser ray, especially for the intractable(diabetic) skin ulceration.

• Korean Journal of Acupuncture
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• v.40 no.4
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• pp.141-148
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• 2023

Objectives : The purpose of this study is to investigate on the application of the yttrium aluminum garnet (YAG) lasers for acupoints irradiation. Methods : We conducted a systematic search for peer-reviewed studies published from inception to November 2023, in the following electronic databases: PubMed, Scopus, and Web of Science in English, Science ON, Oriental Medicine Advanced Searching Integrated System (OASIS) and Research Information Sharing Service (RISS) in Korean, and China National Knowledge Infrastructure (CNKI) and Wanfang in Chinese, and Japan Science Technology Information Aggregator, Electronic (J-STAGE) and Citation Information by NII (CiNii) in Japanese. Inclusion criteria were original articles including clinical and experimental studies related with YAG lasers for acupoints including Ashi or meridian sinews. Results : Among the 8 selected studies, there were 7 studies on human subjects and 1 study on animals, 7 studies on Nd:YAG (1,064 nm) laser, and 1 study on Er:YAG (2,940 nm) laser. A total of 16 acupoints were used, 15 of which were in the face and 1 of which was located in the foot. In addition, there were two studies using Ashi. 4 studies looked at the effect of pain relief, 2 studies looked at safety, 1 study looked at changes in blood flow, and 1 study looked at the effect of skin care. There were no reported adverse events, and the YAG laser was confirmed to be safe and effective in pain relief, beautifying the skin, and increasing blood flow. Conclusions : We suggest that high intensity YAG lasers can be applied to laser acupuncture or laser moxibustion. YAG lasers are considered to be worth using for various clinical indications of Korean medicine because of photobiomodulation effects, analgesic action, and deep penetration depth. Further scientific research and clinical evidences should be warranted.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1213-1218
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• 2004

The present article reports extensive numerical results on the non-local characteristics of ultra-short pulsed laser-induced breakdowns of fused silica ($SiO_{2}$) by using the multivariate Fokker-Planck equation. The nonlocal type of multivariate Fokker-Planck equation is modeled on the basis of the Boltzmann transport formalism to describe the ultra-short pulsed laser-induced damage phenomena in the energy-position space, together with avalanche ionization, three-body recombination, and multiphoton ionization. Effects of electron avalanche, recombination, and multiphoton ionization on the electronic transport are examined. From the results, it is observed that the recombination becomes prominent and contributes to reduce substantially the rate of increase in electron number density when the electron density exceeds a certain threshold. With very intense laser irradiation, a strong absorption of laser energy takes place and an initially transparent solid is converted to a metallic state, well known as laser-induced breakdown. It is also found that full ionization is provided at intensities above threshold, all further laser energy is deposited within a thin skin depth.

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.230-234
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• 2019

Medical laser equipment using optical energy is used to surgery and treat diseases by destroying and removing tissue. Domestic laser equipment has been used steadily in the skin and cosmetics sectors and has been changed to radiate high-power energy in a wide range to shorten patient treatment time. However, side effects such as burns and damage of normal tissues occurred. To solve this problem, techniques for detecting lesions using an imaging device and selectively radiating the laser have been developed. In this study, we proposed an evaluation method to evaluate the safety and performance of target detection accuracy, laser irradiation accuracy and motion protection device technology derived from product analysis and investigation. Finally, the validity of the evaluation method was evaluated by evaluating the imaging device based laser equipment as the proposed evaluation method.

• Journal of Oral Medicine and Pain
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• v.19 no.1
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• pp.33-43
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• 1994

The purpose of this paper was to observe the influence of Ga-As semiconductor-low power generating laser on she appearance and actions of tenascin, extracellular matrix, as healing process of intentional wound on the experimental animals is taking place. 35 rabbits were divided into control and experimental group. ; and on each, 3mm-long and 2mm-deep, surgical wounds were created on buccal oral mucosa and thoracodorsal portion of skin. Ga-As laser was applied to the experimental group starting a day of the day the wounds were created , the laser was applied for 5 minutes every other day. Tissue samples were taken after the 2, 4, 7, 10, and 14 days after wound formation. Then tile healing process of experimental and control groups were observed and compared, using light microscope. Afterwards, the samples were immunohistochemical stained and again observed tenascin by quantitative measuring. The following results were obtained : 1. Tenascin was observed prevalently on epithelial cells, border area of dermis, and interstitial matrix between connective tissue layers in both experimental and control groups. 2. In oral mucosa, the experimental group showed significant increase in the appearance of tenascin after 4 days compared to the control group, but after 10 days, it decreased to a point which is even less than the control group. 3. In the skin samples, the pattern of appearance of tenascin was the same in both groups, but there was some difference concerning when the peak period was shown, In the experimental group, the peak period of tenascin expression was the 7 days after wound formation in epithelium and connective tissue. In the control group, the peak period was 10 days after. 4. In both the experimental and control groups, tenascin first appeared in the epithelium near the wound area and submucosa, and then spread on the underlying connective tissue. In conclusion, appearance of tenascin is closely related to regeneration of epithelium and development of granulation tissue : therefore, low power laser, which fastnes appearance of tenascin, is sure to faciltate healing process of oral mucosa.