• Proceedings of the Botanical Society of Korea Conference
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• 1993.07a
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• pp.1-36
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• 1993

It is possible to regenerate plants from calli, single cells and protoplasts of numerous species via organogenasis or embryogenesis in cell and tissue culture systems. Also such regeneration of plants can directly occur from cells of explants. However certain plant species has not been yet provided cultures suitable for plant regeneration from cells or tissues. For example, we have to confirm the regenerability of plant from cells before preparing transformed cells for application. Even more, it is very important to notice that regenerated plants in cell and tissue cultures often show structural abnormality. The mojority of those plants is functionally disordered and eventually cases degenerated. One of such examples is vitreous plants which are manifested mainly in the leaves and manifesteds to a lesser extent in the stems and roots. Regenerants in suspension cultures show more frequent vitrification than on gelled media so that relative humidity and water potential are the key factors involved in abnormal morphogenesis in vitro. The other is that somatic embryos formed in media containing BAP or high concentration of sucrose show frequently cotyledon aberrancy such as polycotyledon and born type cotyledon. The embryos with aberrant cotyledon of Codonopsis lanceolata could not germinate or regenerate into plants in many cases. In contrast, the polycotyledon embryos of Aralia cordata germinated in higher percentage than two cotyledonary embryos, but horn type cotyledonary embryos rarely germinated. The major cause of poor germination is the abnormal development of plumule apex meristem.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.80-80
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• 2003

Insulin-dependent or Type 1 diabetes mellitus (IDDM) has been associated with an increased severity of periodontal disease. Since periodontal ligament (PDL) cells play a significant role in maintenance and regeneration of mineralized tissue, the success of procedures, such as guided tissue regeneration, is directly related to the ability of these cells to augment mineralized tissue. In this study, we investigated the time- and dose-dependent effect of high glucose on the proliferation and collagen synthesis of human periodontal ligament (PDL) cells. PDL cells were treated with high glucose (22mM, 33mM, 44mM) for 1 or 2 days. High glucose significantly inhibited proliferation of PDL cells as a time- and dose-dependent manner as evidenced by MTT assay. PDL cells were cultured in high glucose media (22mM, 33mM, 44mM) for 24 h. The ratio of collagen content to total protein was evaluated, and the gene expression of type I collagen was assessed by RT - PCR. The high concentration of glucose inhibited collagen synthesis, a marker of bone formation activity. This study indicated high glucose concentration could alter the metabolism of periodontal ligament cell, leading to alveolar bone destruction.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1490-1495
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• 2009

The development of nanotechnology has penetrated the fields of biology and medicine, resulting in remarkable applications for tissue regeneration. In order to apply this technology to tissue engineering, we have developed nano-scaled 3D scaffolds consisting of growth factor-loaded heparin/poly(l-lysine) nanoparticles (NPs) attached to the surface of polymeric micro spheres via polyionic complex methods. Growth factor-loaded NPs were simply produced as polyelectrolyte complexes with diameters of 100-200 nm. They were then coated onto positively charged poly(lactic-co-glycolic acid) (PLGA) pretreated with polyethyleneimine to enable cell adhesion, proliferation, and stimulation of neurite outgrowth. Propidium iodide staining and $\beta$-tubulin analysis revealed that neuronal PC12 cells proliferated extensively, expressed significant amounts of b-tubulin, and showed well-structured neurite outgrowth on polymeric microspheres by stimulation with growth factors. These results suggest that cellular adhesion and biological functionality on prepared PLGA microspheres enabled terminal differentiation of neuronal cells.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.406-417
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• 2020

Purpose: This study investigated whether the placement of ribose cross-linked collagen (RCLC) membranes without primary soft tissue closure predictably resulted in sufficient alveolar ridge preservation in contained and non-contained extraction sockets. Methods: Membranes were positioned across extraction sockets, undermining full-thickness flaps, and the gingival margins were fixed by double-interrupted sutures without crossed horizontal mattress sutures for 1 week. In non-contained sockets, a bone substitute was used to support the membrane within the bony envelope. Radiographs and clinical images obtained 4 months later were analyzed by ImageJ software using non-parametric tests. Results: In 18 patients, 20 extraction sockets healed uneventfully and all sites received standard-diameter implants (4.1, 4.8, or 5.0 mm) without additional bone augmentation. Soft tissues and the muco-gingival border were well maintained. A retrospective analysis of X-rays and clinical photographs showed non-significant shrinkage in the vertical and horizontal dimensions (P=0.575 and P=0.444, respectively). The new bone contained vital bone cells embedded in mineralized tissues. Conclusions: Within the limitations of this pilot study, open healing of RCLC membranes may result in sufficient bone volume for implant placement without additional bone augmentation in contained and non-contained extraction sockets.

• Journal of Periodontal and Implant Science
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• v.30 no.3
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• pp.539-555
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• 2000

Recently, it was reported that enamel matrix derivative may be beneficial in periodontal regeneration procedures in expectation of promoting new bone and cementum formation. The aim of present study was to evaluate the effect of enamel matrix derivative($Emdogain^?$)and Caso4 sulfate paste in 1-wall intrabony defects in beagle dogs. Surgically created 1-wall intrabony defects were randomly assigned to receive root debridement alone or $Emdogain^{(R)}$ or $Emdogain^{(R)}$ and Caso4. Clinical defect size was 4 X 4mm. The control group was treated with root debridement alone,and Experimental group I was treated with enamel matrix derivative application, and Experimental group II was treated with enamel matrix derivative and Caso4 sulfate paste application,. The healing processes were histologically and histometrically observed after 8 weeks and the results were as follows: 1. The length of junctional epithelium was $0.41{\pm}0.01mm$ in the control group, $0.42{\pm}0.08mm$in the experimental group I and $0.50{\pm}0.13mm$in the experimental group II. 2. The connective tissue adhesion was $0.28{\pm}0.02mm$ in the control group, $0.13{\pm}0.08mm$ in the experimental group I and $0.19{\pm}0.02mm$ in the experimental group II. 3. The new cementum formation was $3.80{\pm}0.06mm$ in the control group, $4.12{\pm}0.43mm$ in the experimental group I and $4.34{\pm}0.71mm$ in the experimental group II. 4. The new bone formation was $1.43{\pm}0.03mm$ in the control group, $1.53{\pm}0.47mm$ in the experimental group I and $2.25{\pm}1.35mm$ in the experimental group II. Although there was limitation to present study, the use of enamel matrix derivative in the treatment of periodontal 1-wall intrabony defect enhanced new cementum and bone formation. Caso4 sulfate paste will be the candidate for carriers to deliver enamel matrix derivative, and so enhance the regenerative potency of enamel matrix derivative.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.43-48
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• 2004

As an initial step for future genetic manipulations to improve forage characteristics of Italian ryegrass (Lolium multiflorum Lam.), an efficient tissue culture system was established and the factors affecting plant regeneration were evaluated. MS medium containing 5mg/L 2,4-D was optimal for embryogenic callus induction from mature seed and had a strong effect on successive plant regeneration. The plant regeneration frequency was observed at above 70％ when embryogenic calli induced were transferred to N6 medium supplemented with 1mg/L 2,4-D and 5mg/L BA. Among several basic media tested, MS and N6 medium were optimal for callus induction and plant regeneration, respectively. Genotype was an important factor in plant regenerability. 'Jeanne' showed the highest regeneration frequency of 73％. A short tissue culture period and high-frequency regeneration system established in this study will be useful for molecular breeding of Italian ryegrass through genetic transformation.

• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.103-113
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• 2007

The purpose of this study was to measure the thickness of masticatory mucosa in the hard palate as a donor site for mucogingival surgery by using computerized tomography(CT), Thickness measurements were performed in 84 adult patients who took CT on maxilla for implant surgery and 24 standard measurement points were defined in the hard palate according to the gingival margin and mid palatal suture. Radiographic measurements were utilized after calibration for standardization. Data were analyzed to determine the differences in mucosal thickness by gender, age, tooth positions and depth of palatal vault. The results of this study were as follows: 1. Mean thickness of palatal masticatory mucosa was $3.93{\pm}0.6mm$ and females had significantly thinner mean masticatory mucosa($3.76{\pm}0.56mm$) than males($4.04{\pm}0.6mm$)(p<0.05). 2. The thickness of palatal masticatory mucosa increased by aging. 3. Depending on position, masticatory mucosa thickness increased from canine to premeolar, but decreased at the first molar, and increased again in the second molar region(p<0.0001). 4. No significant difference in mean thickness of palatal masticatory mucosa were indentified between low palatal vault group and high palatal vault group(p>0.05). The results suggest that canine and premolar area appears to be the most appropriate donor site for soft tissue grafting procedure. The measurement of the thickness of palatal masticatory mucosa by using computerized tomography can offer useful information clinically but further studies in as-sessing the validity and reliability of the method using computerized tomography is needed.

• Journal of Periodontal and Implant Science
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• v.28 no.1
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• pp.145-160
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• 1998

The ultimate goal of periodontal therapy is the regeneration of periodontal tissue which has been lost due to destructive periodontal disease, and numerous kinds of materials and techniques have been developed to achieve this goal. Bone grafts include autografts, allografts, xenografts and synthetic grafts. Among the synthetic grafts, bioactive glass has been used in dentistry for more than ten years and Fetner reported improved new bone formation and more amount of new attachment after grafting PerioGlas, a kind of bioactive glass, in 2-wall defects of monkeys in 1994. It Is well known that 1-wall defects have less osteogenic potential and more epithelial migration, so we need to study the erect of bioactive glass in 1-wall dejects in dogs. The present study evaluates the effect of bioactive glass on the epithelial migration, alveolar bone regeneration, cementum formation and gingival connective tissue attachment in intrabony detects of dogs. Four millimeter deep and four millimeter wide 1-wall defects were surgically cheated in the mesial aspects of premolars. The test group received bioactive glass with a flap procedure and the control underwent flap procedure only. Histologic analysis after 8 weeks of healing revealed the following results: 1. The height of gingival margin was 1.30{\pm}0.73mm$ above CEJ in the control and $1.40{\pm}0.78mm$ in the test group. There was no statistically significant difference between the two group. 2. The length of epithelial growth (the distance from CEJ to the apical end of JE) was $1.74{\pm}0.47mm$ in the control and $1.12{\pm}0.36mm$ in the test group. These was a statistically significant difference between the two groups (P<0.01). 3. The length of new cementum was $2.06{\pm}0.73mm$ in the control and $2.62{\pm}0.37mm$ in the test group. There was no statistically significant difference between the two groups. 4. The length of new bone was $1.83{\pm}0.74mm$ in the control and $2.39{\pm}0.59mm$ in the test group. There was no statistically significant difference between the two groups. These results suggest that the use of bioactive glass 1-wall intrabony defects has significant effect on the prevention of junctional epithelium migration, but doesn't have any significant effect on new bone and new cementum formation.

• 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.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.237.3-238
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• 2003

Tissue engineering may be adequately defined as the science of persuading the body to regenerate or repair tissue that fail to regenerate or heal spontaneously. In the various techniques of cartilage tissue engineering, the use of 3-dimensional polymeric scaffolds implanted at a tissue defect site is usually involved. These scaffolds provided a framework for cells to attach, proliferate, and form extracellular matrix(ECM). The scaffolds may also serve as carriers for cells and/or growth factors. In the ideal case, scaffold absorb at a predefined rate so that the 3-dimensional space occupied by the initial scaffold is replaced by regenerated host tissue. (omitted)