• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.6
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• pp.379-391
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• 2003

The present study was undertaken to evaluate bone regenerative capacity around titanium screw implants placed in irradiated rat's tibiae. At one week after single 15-Gy dose irradiation, miniaturized titanium screw implants were inserted into anterior aspect of the upper tibia of rats weighing 200-250g. Seventy rats were involved: 35 rats were control and 35 rats radiation group. The rats were killed at different intervals as 1, 2, 3, 4, 6, 8, 12 weeks after implantation for histologic observation, histomorphometric analysis and immunohistochemical study with fibronectin and CD34 antibody. 1. Histologically, various stages of bone maturation and ossification can be seen at 4 weeks and regenerated bone close to edges demonstrates more advanced calcification, and network of new bone are well formed at 12 weeks in non-irradiated group. In contrast, active bone formation with increased contact of newly formed bone to implant surface was noted at 4 weeks and a significant amount of new bone formation and bone-implant contact is oberved at 12 weeks in irradiated group. 2. Histomorphometrical analysis confirmed these histologic findings. A significant difference in implant-bone contact and bone density was measured between the control and radiation group. Mean MBD was 62.2% in control group and 27.5% in radiation group, mean MBIC was 86.6% in control group and 47.7% in radiation group, and mean TBIC was 87.3% in control group and 45.6% in radiation group at 12 weeks after implantation. 3. In immunohistochemical study with fibronectin and CD34, radiation reduced hematopoietic progenitor cells severely and disturbed differentiation of osteoblast in bone marrow. The results of this study revealed bone healing capacity around implant after radiation therapy was severely impaired and irradiation reduces the capacity for osseointegration of titanium implants. Many factors including radiation dose, period between radiation and implantation, bone quality, time elapse between first and second surgery, type of prosthetics and hyperbaric oxygen therapy must be considered carefully in postradiation implantation.

• Journal of Life Science
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• v.26 no.7
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• pp.835-846
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• 2016

Chemo-resistance is the biggest issue of effective cancer therapy. ABCG2 is highly correlated with multi-drug resistance, and represent a typical phenotype of multiple cancer stem-like cells. Accumulating evidence recently reported that oncolytic viruses represent a new strategy for multiple aggressive cancers and drug resistant cancers including cancer stem cell-like cells and ABCG2 expressing cells. In this study, we generated an evolutionally engineered vaccinia virus, SLJ-496, for drug-resistant cancer therapy. We first showed that SLJ-496 treatment enhanced tumor affinity using cytopathic effect assay, plaque assay, as well as cell viability assay. Next, we clearly demonstrated that in vitro SLJ-496 treatment represents significant cytotoxic effect in multiple cancers including colorectal cancer cells (HT-29, HCT-116, HCT-8), gastric cancer cells (AGS, NCI-N87, MKN-28), Hepatocellular carcinoma cells (SNU-449, SNU-423, SNU-475, HepG2), as well as mesothelioma cell (NCI-H226, NCI-H28, MSTO-221h). Highly ABCG2 expressing HT-29 cells represent cancer stem like phenotype including stem cell marker expression, and self-renewal bioactivities. Interestingly, we demonstrated that in vitro treatment of SLJ-496 showed significant cytotoxicity effect, as well as viral replication capacity in ABCG2 overexpressing cell. In addition, we also demonstrated the cytotoxic effect of SLJ-496 in Adriamycin-resistant cell lines, SNU-620 and ADR-300. Taken together, these findings provide us a pivotal clue that cancer therapy using SLJ-496 vaccinia virus might be new therapeutic strategy to overcome ABCG2 expressing cancer stem-like cell and multiple chemo-resistance cancer cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.1042-1047
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• 2002

Recently, many natural medicines, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, anti-inflammatory and regenerative potential for periodontal tissues. Cortex Eucommiae, Eupoly phaga, Semen Cuscutae, Halloysitum Rubrum have been traditionally used as medicines for treatment of bone disease in Korea. The objective of the present study is to examine the ability of alkaline phosphatase (ALP) activity in human fetal osteoblast cell line (hFOB1) with several natural medicines. hFOB1 added DMEM/F-12 were cultured with dexamethasone as a positive control, and with each natural medicine. ALP activity was measured by spectrophotometer for enzyme activity and naphthol AS-Bl staining was performed for morphometry. All of the natural medicines induced a higher ALP activity compared to negative control, especially, Cortex Eucommiae increased an ALP activity in all experimental groups (p<0.05). In naphthol AS-Bl staining, all of the natural medicines of this study increased the stained area compared to negative control. Especially, Cortex Eucommiae and Eupoly phaga showed statistical significance compared to negative control (p<0.05). These results indicate that Cortex Eucommiae, Eupoly phaga, Semen Cuscutae, Halloysitum Rubrum have an inducing ability of ALP synthesis on osteoblasts.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.158-158
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• 2015

Myoblast are myogenic precursors that proliferate, activate, and differentiate on muscle injury to sustain the regenerative capacity of skeletal muscle; The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for Nitric oxide (NO) in muscle biology1,2,3. However, the expression and subcellular localization of NO in muscle development and myoblast differentiation are largely unknown. In this study, we examined effects of the nitric oxide generated by a microwave plasma torch, on proliferation/differentiation of rat myoblastic L6 cells. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimetres per minute. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the ratio of oxygen gas, and the microwave power4. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to L6 skeletal muscles. Differentiation of L6 cells into myotubes was significantly enhanced the differentiation after nitric oxide treatment. Nitric oxide treatment also increase the expression of myogenesis marker proteins and mRNA level, such as myogenin and myosin heavy chain (MHC), as well as cyclic guanosine monophosphate (cGMP), However during the myotube differentiation we found that NO activate oxidative stress signaling erks expression. Therefore, these results establish a role of NO and cGMP in regulating myoblast differentiation and elucidate their mechanism of action, providing a direct link with oxidative stress signalling, which is a key player in myogenesis. Based on these findings, nitric oxide generated by plasma can be used as a possible activator of cell differentiation and tissue regeneration.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.3
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• pp.294-302
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• 2004

In this study, we developed the inverter system to control Induction motor for the vertically circulation parking facility. In the case of calling a pallet, a car parking space, we basically stoned conventional system's problems, pallet is uncontrollable to the fixed position and braking system was worn by forcer braking with remaining speed. Also, by appling to converter controller, added to power regenerative control function, we confirmed the reduce of power supply capacity and the energy saving effect according to increasing operation frequency. The validity of this system is verified by 55kw induction motor driving system. Via this study, the proposed system shows the efficient use of parking facility and good operation characteristics by implementing position and speed control effectively on condition of load and shows energy saying effect by power factor control for the vertically circulation parking facility operation.

• Journal of Oral Medicine and Pain
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• v.39 no.1
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• pp.2-9
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• 2014

Purpose: The purpose of this study was to compare the clinical and radiographic features of temporomandibular joint (TMJ) osteoarthritis (OA) between adolescents and middle-old aged patients. Methods: The subjects were chosen among the patients who presented to the Department of Oral Medicine of Pusan National University Hospital and were diagnosed with TMJ OA by clinical exam, X-ray and cone-beam computed tomography (CBCT) from 2010 to 2011. We investigated 93 adolescent patients (12-19 years) and 53 middle-old aged (>45 years) patients who observed the erosive bony changes in TMJ. CBCT scans were retaken at intervals at an average of 8 months. Results: The adolescent patients showed unilateral degenerative changes more often, and the middle-old aged patients showed degenerative changes more frequently on both sides. The transition of bone changes to the improved group occurred most commonly in both the adolescent and middle-old aged patients. The adolescent patients were more likely to improve than middle-old aged patients. In the adolescent patients, loss of erosion and subjective symptoms occurred in shorter periods than in the middle-old aged patients. In the adolescent patients, the transition of erosion was distributed into proliferative, normal, and shortening in order. In the middle-old aged patients, the transition of erosion was distributed into shortening, proliferative, and normal in order. Conclusions: The clinical and radiographic features of TMJ OA are a significantly different between the adolescent and middle-old aged patients. Moreover, the difference by age of the adaptive and regenerative capacity of TMJ affects the prognosis of TMJ OA and adolescent patients have a better prognosis after treatment.

• Journal of Periodontal and Implant Science
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• v.30 no.3
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• pp.553-569
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• 2000

Many natural medicines have been studied for their capacity and effects of antibacterial, anti-inflammatory and regenerative potential in periodontal tissues. Safflower seed has been traditionally used as a drug for treatment of bone fracture in oriental medicine. The purpose of the present study was to compare the effects of safflower seed extract and bone substitute on bone formation and regeneration in artificial defects in mongrel dogs. The bony defects were made with round bur at mandible and tibia. Extracts of safflower seed and bovine bone were placed directly at each defect for experimental group, and the defect of control group was sutured without any other treatment. Experimental animals were sacrificed at 8 weeks. And then histopathologic reading and histomorphometric study was done. There was not significant differences between control and experimental groups in osteoclastic activity and infiltration of inflammatory cells. However, new capillary proliferation, fibrosis and new bone formation were prominent in safflower seed extract group. The mandibular defects of safflower seed extract group were healed with dense connective and bony tissues, and endochondral bone formation was observed in tibial defect of safflower seed extract group only. New bone area of safflower seed extract group was more significantly increased than that of control and that of bone substitute group. These results indicate that direct local application of safflower seed extracts on bony defects seems to reduces the early inflammatory response and to promotes the bone regeneration.

• Journal of Periodontal and Implant Science
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• v.41 no.1
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• pp.30-43
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• 2011

Purpose: Under different culture conditions, periodontal ligament (PDL) stem cells are capable of differentiating into cementoblast-like cells, adipocytes, and collagen-forming cells. Several previous studies reported that because of the stem cells in the PDL, the PDL have a regenerative capacity which, when appropriately triggered, participates in restoring connective tissues and mineralized tissues. Therefore, this study analyzed the genes involved in mineralization during differentiation of human PDL (hPDL) cells, and searched for candidate genes possibly associated with the mineralization of hPDL cells. Methods: To analyze the gene expression pattern of hPDL cells during differentiation, the hPDL cells were cultured in two conditions, with or without osteogenic cocktails (${\beta}$-glycerophosphate, ascorbic acid and dexamethasone), and a DNA microarray analysis of the cells cultured on days 7 and 14 was performed. Reverse transcription-polymerase chain reaction was performed to validate the DNA microarray data. Results: The up-regulated genes on day 7 by hPDL cells cultured in osteogenic medium were thought to be associated with calcium/iron/metal ion binding or homeostasis (PDE1A, HFE and PCDH9) and cell viability (PCDH9), and the down-regulated genes were thought to be associated with proliferation (PHGDH and PSAT1). Also, the up-regulated genes on day 14 by hPDL cells cultured in osteogenic medium were thought to be associated with apoptosis, angiogenesis (ANGPTL4 and FOXO1A), and adipogenesis (ANGPTL4 and SEC14L2), and the down-regulated genes were thought to be associated with cell migration (SLC16A4). Conclusions: This study suggests that when appropriately triggered, the stem cells in the hPDL differentiate into osteoblasts/cementoblasts, and the genes related to calcium binding (PDE1A and PCDH9), which were strongly expressed at the stage of matrix maturation, may be associated with differentiation of the hPDL cells into osteoblasts/cementoblasts.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.96-104
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• 2004

This paper proposes a dc power regenerating systems, which can generate the excessive dc power from dc bus line to ac supply in substations for traction system The proposed regeneration inverter system for dc traction can be used as both an inverter and an active power filter(APF). As an regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverters, output transformers, and an LCL filter.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.49-60
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• 2003

Several growth factors and polypeptides are not commonly yet used for regenerators of bone tissue or alveolar bone because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many herbal medicines, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, antiinflammatory and regenerative potential of periodontal tissues. Morindae Radix, Cibotium Barometz (L.), Albizziae Cortex, Cistandhis Herba have been traditionally used as medicines for treatment of bone disease in Eastern medicine. The objective of the present study is to examine the ability of alkaline phosphatase (ALP) activity of human fetal osteoblast (hFOB1) when several natural medicines were supplemented. hFOB1 were cultured with Dulbecuo's Modified Eagle's Medium Nutrient Mixture F-12 HAM ( DMEM/F-12 1:1 Mixture, Sigma, USA) and negative control, dexamethasone (positive control), and each natural medicines for 3 days. And then ALP activity was measured by spectrophotometer for enzyme activity and Alizarin red S staining for morphometry. Among the natural medicines of this study, Morindae Radix, Cibotium Barometz (L.) and Cistanchis Herba induced higher activity of ALP synthesis than negative controls in all experimental group. Albizziae Cortex showed mild increases than negative control group. According to measurement of positively stained area, all of the natural medicines of this study increased compared to negative control. Especially, Cibotium Barometz (L.) and Cistanchis Herba showed statistical significance compared to negative control (p<0.05). These results indicate that Morindae Radix, Cibotium Barometz (L.), Albizziae Cortex, Cistandhis Herba have an inducing ability of ALP synthesis on osteoblast.