• International Journal of Stem Cells
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• v.16 no.1
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• pp.93-107
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• 2023

Background and Objectives: Chronic periodontitis can lead to alveolar bone resorption and eventually tooth loss. Stem cells from exfoliated deciduous teeth (SHED) are appropriate bone regeneration seed cells. To track the survival, migration, and differentiation of the transplanted SHED, we used super paramagnetic iron oxide particles (SPIO) Molday ION Rhodamine-B (MIRB) to label and monitor the transplanted cells while repairing periodontal bone defects. Methods and Results: We determined an appropriate dose of MIRB for labeling SHED by examining the growth and osteogenic differentiation of labeled SHED. Finally, SHED was labeled with 25 ㎍ Fe/ml MIRB before being transplanted into rats. Magnetic resonance imaging was used to track SHED survival and migration in vivo due to a low-intensity signal artifact caused by MIRB. HE and immunohistochemical analyses revealed that both MIRB-labeled and unlabeled SHED could promote periodontal bone regeneration. The colocalization of hNUC and MIRB demonstrated that SHED transplanted into rats could survive in vivo. Furthermore, some MIRB-positive cells expressed the osteoblast and osteocyte markers OCN and DMP1, respectively. Enzyme-linked immunosorbent assay revealed that SHED could secrete protein factors, such as IGF-1, OCN, ALP, IL-4, VEGF, and bFGF, which promote bone regeneration. Immunofluorescence staining revealed that the transplanted SHED was surrounded by a large number of host-derived Runx2- and Col II-positive cells that played important roles in the bone healing process. Conclusions: SHED could promote periodontal bone regeneration in rats, and the survival of SHED could be tracked in vivo by labeling them with MIRB. SHED are likely to promote bone healing through both direct differentiation and paracrine mechanisms.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.372-377
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• 2007

For more than 2,500 years, surgical teaching has been based on the so called "see one, do one, teach one" paradigm, in which the surgical trainee learns by operating on patients under close supervision of peers and superiors. However, higher demands on the quality of patient care and rising malpractice costs have made it increasingly risky to train on patients. Minimally invasive surgery, in particular, has made it more difficult for an instructor to demonstrate the required manual skills. It has been recognized that, similar to flight simulators for pilots, virtual reality (VR) based surgical simulators promise a safer and more comprehensive way to train manual skills of medical personnel in general and surgeons in particular. One of the major challenges in the development of VR-based surgical trainers is the real-time and realistic simulation of interactions between surgical instruments and biological tissues. It involves multi-disciplinary research areas including soft tissue mechanical behavior, tool-tissue contact mechanics, computer haptics, computer graphics and robotics integrated into VR-based training systems. The research described in this paper addresses the problem of characterizing soft tissue properties for medical virtual environments. A system to measure in vivo mechanical properties of soft tissues was designed, and eleven sets of animal experiments were performed to measure in vivo and in vitro biomechanical properties of porcine intra-abdominal organs. Viscoelastic tissue parameters were then extracted by matching finite element model predictions with the empirical data. Finally, the tissue parameters were combined with geometric organ models segmented from the Visible Human Dataset and integrated into a minimally invasive surgical simulation system consisting of haptic interface devices and a graphic display.

• Toxicological Research
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• v.25 no.4
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• pp.231-235
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• 2009

Trace lead detection for cyclic voltammetry (CV) and square-wave (SW) stripping voltammetry was performed using mercury immobilized onto a carbon nanotube electrode (HNPE). Using the characteristics of mercury and the catalytic carbon nanotube structure, a modified technique, the $0.45{\mu}g/l$ detection limit of lead ion was attained. The developed method can be applied to pond water, fish tissue, plant tissue, and in vivo direct assay.

• Korean Journal of Plant Tissue Culture
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• v.22 no.5
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• pp.273-276
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• 1995

In vitro propagation of Neoregeria carorinae 'Tricolor' was achieved by using immature flowers and lateral buds, and the plantlets from tissue culture were transplanted and cultivated in greenhouse. The picking times of explants to decrease disappearance of stripes, and in vivo the growth and flowering of regenerated plantlets as influenced by in vivo healed nun were investigated. The normal plantlet were obtained at a frequency of 67%, in the culture of immature flowers picked at 4 weeks after flower bud differentiation, while all leaf stripes disappeared in the culture of immature flowers picked 1 and 5 weeks after flower bud differentiation. In vivo growth of plantlet from immature flower buds was better than those from lateral buds, and the flowering of 27.8% showed in the greenhouse culture of plantlet from immature culture, but the plantlets from lateral buds did not flower at all. The plantlets rooted on the medium with 0.5 mg/L IBA were the most favorable in green house culture, and the kinds and concentrations of auxin in vitro did not have any influence on variation of plane cultured in greenhouse.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.911-914
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• 2005

Soft tissue characterization and modeling based on living tissues has been investigated in order to provide a more realistic behavior in a virtual reality based surgical simulation. In this paper, we characterize the nonlinear viscoelastic properties of intra-abdominal organs using the data from in vivo animal experiments and inverse FE parameter estimation algorithm. In the assumptions of quasi-linear-viscoelastic theory, we estimated the nonlinear material parameters to provide a physically based simulation of tissue deformations. To calibrate the parameters to the experimental results, we developed a three dimensional FE model to simulate the forces at the indenter and an optimization program that updates new parameters and runs the simulation iteratively. The comparison between simulation and experimental behavior of pig intra abdominal soft tissue are presented to provide a validness of the tissue model using our approach.

• Journal of Biomedical Engineering Research
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• v.17 no.2
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• pp.227-234
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• 1996

This paper is the study of the diffusion constant in order to calculate the percent oxygenation and percent blood volume using reflectance light within biological tissue. The diffusion constant play major role in percent oxygenation and percent blood volume and varies with the biological material such as hemolyzed blood, whole blood, dermis and epidermis in vivo tissue. The diffusion constant can be modeled to consist of a contribution from bloodless tissue and blood present in tissue. The reflectance light for experimental are red light of 660nm, infrared light of 880nm, green light of 569nm. The correlation between the diffusion constant and biological tissue was analyzed by the intensity of reflectance light at different depth within human limb. The reflectance light was changed in response to physiological changes within biological tissue. The data for diffusion constant were obtained at different depth beneath the surface of the skin and will be utilized to amen the percent oxygenation and percent blood volume.

• Physical Therapy Korea
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• v.10 no.1
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• pp.15-27
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• 2003

Therapeutic ultrasound is commonly applied for deep heating in physical therapy setting. However, it is difficult to determine the exact application dosage and to confirm the immediate heating effect. Microwave Radio-Thermometer (MRT) can measure the temperature by the electromagnetic energy in the microwave region of the object that emits above absolute zero temperature. MRT was used for early diagnosis of breast cancer since it was not harmful, non-invasive, and non-ionizing to the human body. The purposes of this study were to investigate how accurately 1.1 GHz RTM (RES Ltd. Russia) measures the change of average temperature in the tissue, and to determine the depth of temperature change measurement. Therapeutic ultrasound was applied (continuous wave for 5 minutes, 1 MHz, intensity of 1.5 $W/cm^2$ [in vitro] and 1.0 $W/cm^2$ [in vivo]) in four different conditions: (1) 30 cases of in vitro specimen of pork, (2) 30 cases of in vitro specimen of pork ankle joint, (3) 10 cases of in vivo canine thigh, and (4) 30 cases of in vivo human body. Intraclass Correlation Coeffients (ICC[3,1]) between average needle probe thermometer below surface and MRT temperature was revealed as followed: (1) Before ultrasound application ICCs ranges above .8 in specimen of pork (15 mm underneath the skin) and above .82 in specimen of pork ankle joint (10~30 mm underneath the skin). (2) After ultrasound application ICCs ranges above .7 in both specimens of pork and pork ankle joint. (3) Before ultrasound application ICCs ranges above .8 in canine thigh (20 mm underneath the skin). (4) After ultrasound application ICCs ranges above .82 in canine thigh. The temperature of the human body increased significantly with the mean of $15^{\circ}C$ in muscle tissue and with the mean of $3.5^{\circ}C$ in joint (p<.00). It was revealed that the average depth of temperature measurement of the tissue by MRT was in between 10 and 35 mm, and determined that the proper temperature measurement band was $36.5{\sim}37.0^{\circ}C$.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.4
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• pp.323-332
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• 2008

Aim of the study: Scaffolds are crucial to tissue engineering/regeneration. Biodegradable polymer/ceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. In this study, poly(L-lactide)/hydroxyapatite(PLLA/HA) composite scaffolds were fabricated for in vivo bone tissue engineering. Material & methods: In this study, PLLA/HA composite microspheres were prepared by double emulsion-solvent evaporation method, and were evaluated in vivo bone tissue engineering. Bone marrow mesenchymal stem cell from rat iliac crest was differentiated to osteoblast by adding osteogenic medium, and was mixed with PLLA/HA composite scaffold in fibrin gel and was injected immediately into rat cranial bone critical size defect(CSD:8mm in diameter). At 1. 2, 4, 8 weeks after implantation, histological analysis by H-E staining, histomorphometric analysis and radiolographic analysis were done. Results: BMP-2 loaded PLLA/HA composite scaffolds in fibrin gel delivered with osteoblasts differentiated from bone marrow mesenchymal stem cells showed rapid and much more bone regeneration in rat cranial bone defects than control group. Conclusion: This results suggest the feasibility and usefulness of this type of scaffold in bone tissue engineering.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.321-328
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• 2011

Various methods have been investigated to increase photon density in soft tissue, an important factor in low-level laser therapy. Previously we developed a compression-controlled low-level laser probe (CCLLP) utilizing mechanical negative compression, and experimentally verified its efficacy. In this study, we used Bezier curves to numerically simulate the skin deformation and photon density variation generated by the CCLLP. In addition, we numerically modeled changes in optical coefficients due to skin deformation using a linearization technique with appropriate parameterization. The simulated results were consistent with both human in vivo and porcine ex vivo experimental results, confirming the efficacy of the CCLLP.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.48-50
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• 2002

Cartilage defects are common and painful conditions that affect people of all ages. Although many techniques have developed, none of the current available treatment options is satisfactory. Recent advances in biology and materials science have pushed tissue engineering to the forefront of new cartilage repair techniques. The purpose of this study is to determine effective regeneration method for tissue-engineered cartilage. A serum free medium was developed for cartilage tissue engineering. Chondrocyte passage number was found to influence greatly on cartilage tissue formation in vivo. Injectable, biodegradable polymer matrix was developed for chondrocyte transplantation through injection. Transplantation of chondrocytes mixed with the injectable matrices resulted in the cartilage formation in nude mice's subcutaneous sites and rabbit knees. This study may lead to the development of tissue-engineered cartilage appropriate for clinical applications.