Alveolar Bone Regeneration by Transplantation of Periodontal Ligament Stem Cells and Bone Marrow Stem Cells in a Canine Peri-Implant Defect Model: A Pilot Study

Kim, Su-Hwan,Kim, Kyoung-Hwa,Seo, Byoung-Moo,Koo, Ki-Tae,Kim, Tae-Il,Seol, Yang-Jo,Ku, Young,Rhyu, In-Chul,Chung, Chong-Pyoung,Lee, Yong-Moo Wiley (John WileySons) 2009 Journal of periodontology Vol.80 No.11

<P>BACKGROUND: The present study was undertaken to evaluate the potential of periodontal ligament stem cells (PDLSCs) and bone marrow SCs (BMSCs) on alveolar bone regeneration in a canine peri-implant defect model. METHODS: Four adult, male beagle dogs were used in this study. Autologous BMSCs from the iliac crests and PDLSCs from extracted teeth were cultured. Three months after extraction, BMSC- and PDLSC-loaded hydroxyapatite/beta-tricalcium phosphate (HA/TCP) (test groups) and cell-free HA/TCP (control group) were implanted in three rectangular, saddle-like peri-implant defects, respectively. The left side of the mandible was initially prepared, and after 8 weeks, the right side was also prepared. The animals were sacrificed after an 8-week healing period. Undecalcified ground sections were prepared. New bone formation and bone-to-implant contact (BIC) were measured histomorphometrically. BMSCs and PDLSCs were fluorescently labeled and traced. RESULTS: Alveolar bone regeneration in surgically created peri-implant saddle-like defects was more effective in test groups than the control group. The BMSC group had the highest new bone formation (34.99% and 40.17% at healing times of 8 and 16 weeks, respectively) followed by the PDLSC group (31.90% and 36.51%) and control group (23.13% and 28.36%), respectively. Test groups exhibited a significantly higher new bone formation than the control group at 8 weeks, but the same was true for only the BMSC group at 16 weeks (P <0.05). Fluorescently labeled cells were identified adjacent to HA/TCP carriers and, partly, near connective tissues and osteoids. CONCLUSION: This study demonstrated the feasibility of using stem cell-mediated bone regeneration to treat peri-implant defects.</P>

Comparison of the Amount of Carbon-14 Radioactive Effluents Discharged From Korean PWRs and PHWRs and Its Resulting Public Dose

Hwa Pyoung Kim,Seong Jun Kim,Jin Ho Son,Chang Ju Song,Wo Suk Choi,Ji Ung Kim,Tae Young Kong 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

As of 2023, there are a total of 24 nuclear power plants (NPPs) in operation in Korea, with 21 pressurized water reactors (PWRs) and three pressurized heavy water reactors (PHWRs). Korean NPPs discharge radioactive effluents into the environment every year. Radioactive effluents from NPPs contain various radionuclides and materials, including 3H, 14C, Noble gas, particulates, and iodine Among the radioactive effluents discharged from Korean NPPs, 14C is a pure beta emitter with a half-life of 5,730 years. The human body can inhale and ingest 14C to cause internal exposure. In addition, the amount of 14C present in the environment is decreasing, but the amount of 14C discharged from NPPs is increasing. 14C discharged to the environment can be inhaled and ingested by the public around NPPs through various pathways. For this reason, it is very important to monitor and manage 14C because it affects the dose of the public around NPPs. Therefore, this study compared and analyzed the average emissions of 14C discharged from PWRs and PHWRs during the recent 10 years (2012-2021). An average of the public dose due to 14C released from NPPs depending on the reactor types from 2012 to 2021 was also compared. It is inevitable to discharge radioactive effluents while operating NPPs. Korea Hydro & Nuclear Power (KHNP) manages and monitors radioactive effluents released into the environment. According to a survey and analysis of 14C discharged from PWRs and PHWRs and the average dose of the public over the recent 10-year (2012-2021) around Korean NPPs, 14C released from PWR accounted for 3.1% of the total discharge but accounted for more than 93.67% of the total public dose. In addition, 14C discharged from PHWRs accounted for 1.12% of the total discharge, but its resulting dose to the public accounted for more than 83.87% of the total public dose. As a result of analyzing the public dose due to 14C from 2012 to 2021, it was gradually increasing every year. Based on these results, monitoring and managing 14C discharge and its resulting doses to the public are important in the future.

Biological efficacy of silk fibroin nanofiber membranes for guided bone regeneration

Kim, Kyoung-Hwa,Jeong, Lim,Park, Ho-Nam,Shin, Seung-Yun,Park, Won-Ho,Lee, Sang-Chul,Kim, Tae-Il,Park, Yoon-Jeong,Seol, Yang-Jo,Lee, Yong-Moo,Ku, Young,Rhyu, In-Chul,Han, Soo-Boo,Chung, Chong-Pyoung Elsevier 2005 Journal of biotechnology Vol.120 No.3

<P><B>Abstract</B></P><P>The favorable biological properties of silk fibroin (SF) nanofiber membrane make it a good candidate for clinical applications as a device in bone and periodontal regenerative therapy. The purpose of this study is to evaluate the biocompatibility of the SF nanofiber membrane, and to examine its effect on bone regeneration in a rabbit calvarial model.</P><P>To examine the biocompatibility of the electrospun SF membrane, we investigated cell proliferation, morphology, and differentiation. The bone regenerative efficacy of the membrane was evaluated in the calvarial defect of rabbits.</P><P>The cell numbers and osteocalcin production labels were significantly increased in accordance with culture period. Cells had a stellate shape and broad cytoplasmic extensions on the membrane. The cells showed activity of ALPase that was comparable to culture dishes, and were calcified similarly to culture dishes. In in vivo tests, a complete bony union across the defects was observed after 8 weeks. At 12 weeks, the defect had completely healed with new bone.</P><P>In conclusion, the SF nanofiber membrane was shown to possess good biocompatibility with enhanced bone regeneration and no evidence of any inflammatory reaction. These results strongly suggest that the SF membrane should be useful as a tool for guided bone regeneration.</P>

Immunomodulatory effect of canine periodontal ligament stem cells on allogenic and xenogenic peripheral blood mononuclear cells

Kim, Hak-Sung,Kim, Kyoung-Hwa,Kim, Su-Hwan,Kim, Young-Sung,Koo, Ki-Tae,Kim, Tae-Il,Seol, Yang-Jo,Ku, Young,Rhyu, In-Chul,Chung, Chong-Pyoung,Lee, Yong-Moo Korean Academy of Periodontology 2010 Journal of Periodontal & Implant Science Vol.40 No.6

Purpose: The aim of this study was to investigate the immunomodulatory effects of canine periodontal ligament stem cells on allogenic and xenogenic immune cells in vitro. Methods: Mixed cell cultures consisting of canine stem cells (periodontal ligament stem cells and bone marrow stem cells) and allogenic canine/xenogenic human peripheral blood mononuclear cells (PBMCs) were established following the addition of phytohemagglutinin. The proliferation of PBMCs was evaluated using the MTS assay. The cell division of PBMCs was analyzed using the CFSE assay. The apoptosis of PBMCs was assessed using the trypan blue uptake method. Results: Periodontal ligament stem cells and bone marrow stem cells inhibited the proliferation of allogenic and xenogenic PBMCs. Both periodontal ligament stem cells and bone marrow stem cells suppressed the cell division of PBMCs despite the existence of a mitogen. No significant differences in the percentages of apoptotic PBMCs were found among the groups. Conclusions: Canine periodontal ligament stem cells have an immunomodulatory effect on allogenic and xenogenic PBMCs. This effect is not a product of apoptosis of PBMCs but is caused by the inhibition of cell division of PBMCs.

지반조건 상호작용을 고려한 풍력발전타워의 공진회피 진동수 산정을 위한 고유진동수 해석 연구

김평화(Kim, Pyoung-Hwa),강성용(Kang, Sung-Young),이윤우(Lee, Yun-Woo),강영종(Kang, Young Jong) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.4

최근 21세기에 접어들어 무분별한 발전의 결과로 석탄, 석유 등의 화석연료가 고갈되고 있으며, 지구 온난화가 진행 중이다. 이미 유럽과 미국 등의 선진국에서는 신재생 에너지 분야에 관심을 갖고 있으며, 그 중에서도 풍력에너지가 많은 관심을 받고 있다. 풍력발전타워는 운용 중 주기적인 하중의 발생으로 만들어지는 주파수를 회피하여 설계를 해야 한다. 일반 적으로 구조해석 과정 시 지반을 고정단 경계조건으로 해석한다. 하지만, 고정단 경계조건의 경우 지반 조건 상호작용을 고려 하지 못하여 목표 진동수를 벗어나게 된다. 본 연구에서는 용량 별 지반경계 조건 및 기초의 근입깊이를 고려한 고유진동수 효과를 연구하였으며, 변수에 따른 차이를 확인하였다. 결과적으로 고정단 경계조건 모델은 지반조건과 근입깊이의 영향을 받지 않으며, Coupled Spring 경계조건 모델은 지반조건에는 영향을 받지만, 근입깊이에는 영향을 받지 않는다. Winkler Spring 경계조건의 경우에는 지반조건과 근입깊이에 모두 영향을 받는다. 하지만, 얕은 깊이의 지반에서는 지반조건의 영향 을 받지 않으므로 Coupled Spring 경계조건 모델을 활용한 지반조건 별 해석을 수행하는 것이 효과적이다 Global warming and the depletion of fossil fuels have been caused by decades of reckless development. Wind energy is one form of renewable energy and is considered a future energy source. The wind tower is designed with a fundamental frequency in the soft-stiff design between the 1P and 3P range to avoid resonance. Usually, to perform natural frequency analysis of a wind tower, the boundary condition is set to the Fixed-End, and soil-pile interaction is not considered. In this study, consideration of the effect of soil-pile interaction on the wind tower was included and the difference in the natural frequency was studied. The fixed boundary condition was not affected by the soil condition and depth of the pile and the coupled spring boundary condition was unaffected by the depth of pile but affected by the depth of the pile, and the Winkler spring boundary condition is affected by both the soil condition and the depth of the pile. Therefore, the coupled spring boundary condition should be used in shallow depth soil conditions because the soil condition does not take the shallow depth soil into consideration.

Genetically Engineered PDL and GF Cells as a Potential Source for Cell Therapy in Bone Regeneration

( Kyoung Hwa Kim ),( Yoon Jeong Park ),( Sang Cheol Lee ),( Hyun Jung Park ),( Tae Li Kim ),( Yang Jo Seol ),( Yong Moo Lee ),( Young Ku ),( Soo Boo Han ),( Chong Pyoung Chung ),( In Chul Rhyu ) 대한치주과학회 2005 대한치주과학회 학술대회자료집 Vol.2005 No.2

A Study on the Radiological Impact Assessment for a High-Level Radioactive Waste Disposal Site

Seong Jun Kim,Jin Ho Son,Hwa Pyoung Kim,Chang Ju Song,Wo Suk Choi,Ji Ung Kim,Tae Young Kong 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Currently, there are 25 nuclear power plants (NPPs) in operation in Korea, including 22 pressurized water reactors (PWRs) and three pressurized heavy water reactors (PHWRs). Two NPPs, including Kori Unit 1 and Wolsong Unit 1, are permanently shut down and awaiting decommissioning. If Kori Unit 2, which is expected to be permanently shut down soon, is included, the number of decommissioning NPPs will be increased to three. Spent fuels (SFs) are continuously generated during the NPP operation, which are stored in an SF storage pool in NPPs to cool down the decay heat emitted from SFs. For safe NPP operation, SFs must be regarded as waste, and a disposal site must be selected to isolate SFs. However, an appropriate site has yet to be selected in Korea. SFs contain long-lived nuclides with a high specific activity. For disposal, it is important to characterize the nuclides in the fuels and delay the migration of the nuclides to the environment when SFs are placed in a future disposal facility. If the disposal container is broken, the nuclides in the fuels escape from the filling material, such as bentonite. These escaped nuclides are dissolved in groundwater and migrate to the surface of the earth. Thus, it is possible to assess the radiological impact, such as the exposure dose during and after the disposal, if the types and characteristics of nuclides in SFs are known. This study investigated the nuclides in SFs and identified exposure scenarios that may occur in the disposal process of SFs and migration characteristics when the nuclides leak into groundwater to propose a dose assessment methodology for workers and the public.

Analysis of Size Distribution for Radioactive Aerosols Generated When Decommissioning Nuclear Power Plants

Ji Ung Kim,Seong Jun Kim,Jin Ho Son,Hwa Pyoung Kim,Chang Ju Song,Wo Suk Choi,Tae Young Kong 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Metal waste generated during the dismantling of a nuclear power plant can be contaminated with radionuclides. In general, the internal structure is very complex. Thus, metal waste requires various cutting processes. When metal waste is cut, aerosols are generated. Aerosols are generally various particles of very small size suspended in the working area and remain for a considerable period. This may cause internal exposure of workers due to inhalation of radioactive aerosols generated when cutting radioactive metal waste. This study investigated various cutting processes and the size distribution of aerosols generated during the cutting process. The cutting process is normally classified into thermal cutting, mechanical cutting, and laser cutting. Thermal cutting includes plasma, flame, and oxygen cutting. Mechanical cutting includes mechanical saws, cutters, nibblers, and abrasive water jets. Stainless steel, carbon steel, aluminum, and copper are commonly used as cutting materials in nuclear power plants. The size of the aerosol generated from cutting showed a very diverse distribution depending on the cutting methods and cutting materials. In general, aerosol size is distributed within 0.1-1 μm. This size distribution is different from the 5 μm aerosol size suggested by the ICRP Publication 66 Lung model. These results show that it is necessary to conduct further studies on the size of aerosols generated when decommissioning nuclear power plants.

Ex vivo bone morphogenetic protein-2 gene delivery using gingival fibroblasts promotes bone regeneration in rats

Shin, Joong-Ho,Kim, Kyoung-Hwa,Kim, Su-Hwan,Koo, Ki-Tae,Kim, Tae-Il,Seol, Yang-Jo,Ku, Young,Rhyu, In-Chul,Chung, Chong-Pyoung,Lee, Yong-Moo Blackwell Publishing Ltd 2010 Journal of Clinical Periodontology Vol.37 No.3

<P><I>Shin J-H, Kim K-H, Kim S-H, Koo K-T, Kim T-I, Seol Y-J, Ku Y, Rhyu I-C, Chung C-P, Lee Y-M</I>. Ex vivo <I>bone morphogenetic protein-2 gene delivery using gingival fibroblasts promotes bone regeneration in rats. J Clin Periodontol 2009; 37: 305–311. doi: 10.1111/j.1600-051X.2009.01522.x</I>.</P><P>Abstract</P><P>Aim</P><P>The aim of the present study was to investigate bone regeneration following ex vivo bone morphogenetic protein-2 (BMP-2) gene delivery using human gingival fibroblasts (HGFs) in rat calvarial defects.</P><P>Materials and Methods</P><P>An 8 mm craniotomy defect was created in Sprague–Dawley rats. The animals were divided into four groups: (1) non-grafted group, the defect was left empty; (2) collagen matrix group, the defect was filled with collagen matrix only; (3) HGF group, the defect was filled with non-transduced HGFs on collagen matrix; (4) BMP-2/HGF group, the defect was filled with BMP-2 gene-transduced HGFs on collagen matrix. Animals were sacrificed at 2 and 4 weeks after surgery, and micro-computed tomographic and histologic observations were performed.</P><P>Results</P><P>The BMP-2/HGF group showed promoted osseous healing of calvarial defects, as compared with the other groups. At both 2 and 4 weeks, regenerated bone area was significantly greater in the BMP-2/HGF group than the other three groups. Quite a few number of transplanted HGFs were observed within the regenerated bone tissues.</P><P>Conclusions</P><P>The results of this study suggest that ex vivo BMP-2 gene delivery induces prominent bone regeneration in vivo and HGFs may be useful as target cells for ex vivo gene therapy.</P>

Research Forum Oral Presentation : Alveolar Bone Regeneration by Transplantation of Periodontal Ligament Stem Cells and Bone Marrow Stem Cells in a Canine Peri-Implant Defect Model: A Pilot Study

( Su Hwan Kim ),( Kyoung Hwa Kim ),( Ki Tae Koo ),( Tae Il Kim ),( Yang Jo Seol ),( Young Ku ),( In Chul Rhyu ),( Chong Pyoung Chung ),( Yong Moo Lee ) 대한치주과학회 2009 대한치주과학회 학술대회자료집 Vol.2009 No.1