• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.4
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• pp.287-293
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• 2009

Long-term treatment with glucocorticoid leads to the development of osteoporosis and osteonecrosis. In contrast to the marked inhibitory effect of pharmacological doses of glucocorticoids on bone formation, the relationship between physiological concentrations of glucocorticoids and osteoprogenitor cell proliferation and phenotypes has not been elucidated yet. In addition, the effects of dexamethasone treatment on the proliferation and osteoblastic differentiation of osteoprogenitor cells are also controversial. The purpose of this study was to examine the effects of dexamethasone on the proliferation and osteoblastic differentiation of periosteal-derived cells. Periosteal-derived cells were obtained from mandibular periosteums and introduced into the cell culture. After passage 3, the cells were further cultured for 21 days in the osteogenic induction medium with different dexamethasone concentrations of 0, 10, and 100 nM. The proliferation and osteoblastic phenotypes of periosteal-derived cells were promoted in dexamethasone-treated cells than in untreated cells. Among the dexamethasone-treated cells, cell proliferation was slightly greater in 10 nM dexamethasone-treated cells than in 100 nM dexamethasone-treated cells. Histochemical staining and the bioactivity of alkaline phosphatase (ALP) were higher in 100 nM dexamethasone-treated cells than in 10 nM dexamethasone-treated cells. Similarly, von Kossa-positive mineralization nodules and calcium content were also more evident in 100 nM dexamethasone-treated cells than in 10 nM dexamethasone-treated cells. These results suggest that dexamethasone enhances the in vitro osteoblastic differentiation of periosteal-derived cells. The present study also demonstrates that higher dexamethasone concentrations reduce the in vitro proliferation of periosteal-derived cells.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.350-357
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• 2017

The purpose of this study was to evaluate the difference of differentiation potential in each passage of dental pulp stem cells from supernumerary tooth (sDPSCs). The sDPSCs were obtained from a healthy 6-year-old male patient under the guidelines and got the informed consent. Cells were cultured until passage number 16 and divided into two groups; 1 - 8 passages as a young group and 9 - 16 passages as an old group. It was taken $2.25{\pm}0.46days$ in a young group and $3.25{\pm}0.46days$ in an old group to propagate cells of each passage until confluence and there were statistically significant differences between two groups (p < 0.05). In every passage, cell morphology was observed with microscope and evaluated the capacity to form high levels of minerals by alizarin red solution staining after treating differentiation medium. Fibroblast-like, spindle shaped, elongated cells and a few nodules were found in uninduced cultures of passage number 1, 8 and 9. But at 16 passage culture, cell size became larger and broader and observed with more nodules. After inducing differentiation, mineralized nodules were detected at the first passage of 7th day culture whereas at the 8 passage culture, nodules were seen clearly at 14th day culture. In addition, the amount of mineralized nodules were remarkably decreased after passage 9. From the data presented in this study, it is recommended to use sDPSCs of passage number within 8 for utilizing as stem cells.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.77-95
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• 2022

The Gonamsan gabbroic complex in the Pocheon area, northwestern region of South Korea consists of a variety types of gabbroic rocks and associated Fe-Ti oxide deposits caused by magmatic differentiation. Post-magmatic intrusions (i.e., gabbroic pegmatite and pyroxene-apatite-zircon rocks) partly intruded into the gabbroic rocks. The gabbroic pegmatite occurs in monzodiorite and oxide gabbro of the complex, intimately and spatially associated with high-grade lenticular Fe-Ti oxide mineralization. The pegmatite can be subdivided into plagioclase-amphibole and pyroxene-olivine pegmatite, in which the contact surface is sharp. The plagioclase-amphibole pegmatite comprises plagioclase and amphibole, with lesser amount of pyroxene, ilmenite, sphene, apatite, and biotite. The pegmatite shows plagioclase-amphibole intergranular texture, in which the open space formed by large plagioclase laths (An_2-26Ab_72-98Or_0-2) are infilled by amphibole. The pyroxene-olivine pegmatite is dark gray to black in color and also contains magnetite, ilmenite, spinel, apatite, and calcite as a minor component. The pyroxene (En_35-36Fs_8-9Wo₅₅) and olivine (Fo_84-85Fa_15-16) partly show a poikilitic texture defined by smaller euhedral olivine enclosed by coarser clinopyroxene. Fe-Ti oxide minerals consist mainly of magnetite and ilmenite that are found interstitially to earlier formed silicates. Subsequently, they are encompassed by reaction rim (almost of amphibole and biotite) along the boundary with surrounding silicate minerals. Under the microscope, magnetite contains a lot of oxyexsolved ilmenite (trellis type) and spinel, and thereby is weakly enriched in magnetite-compatible elements such as Ti, Al, Mg, and V. The structure and textures at the contact zone as well as mineralogical disequilibrium between gabbroic pegmatite and the host gabbroic rocks suggest that the pegmatite may form as a result of accumulation from Fe-rich melt (or liquid) that occurred somewhere rather than in situ form from the host gabbroic rock during the magmatic differentiation. Consequently, the preliminary study suggests that further study on the post-magmatic activities can not only help us improve our understanding on magmatic fractionation but also provide critical information on Fe-Ti oxide mineralization in gabbroic rocks resulting from the magmatic differentiation.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.245-253
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• 2011

Purpose: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. Materials and methods: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). Results: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). Conclusion: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

• Imaging Science in Dentistry
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• v.36 no.4
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• pp.189-198
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• 2006

Purpose: To investigate the in vitro response of MC3T3-E1 osteoblastic cells to X-ray in the presence and absence of 2 deoxy-D-glucose (2-DG) and quercetin (QCT). Materials and Methods: The MC3T3-E1 cells were cultured in an ${\alpha}-MEM$ supplemented with 5 mM 2-DG or $10{\mu}M$ QCT and then the cells were incubated for 12 h prior to irradiation with 2, 4, 6, and 8Gy using a linear accelerator (Mevaprimus, Germany) delivered at a rate of 1.5 Gy/min. At various times after the irradiation, the cells were processed for the analyses of proliferation, viability, cytotoxicity, and mineralization. Results: Exposure of the cells to X-ray inhibited the tritium incorporation, 3-(4, 5-dimethylthiazol-2yl-)-2, 5-diphenyl tetrazolium bromide (MTT)-reducing activity, and alkaline phosphatase (ALP) activity, and caused cytotoxicity and apoptosis in a dose-dependent manner of the X-ray. This effect was further apparent on day 3 and 7 after the irradiation. RA+2-DG showed the decrease of DNA content, cell viability, and increase of cytotoxicity rather than RA. ALP activity increased on day 7 and subsequently its activity dropped to a lower level. 2-DG suppressed the calcium concentration, but visual difference of number of calcified nodules between RA and RA+2-DG was not noticed. RA+QCT showed the increase of DNA content, cell viability, but decrease of cytotoxicity and subG1 stage cells in the cell cycle, and increased calcified nodules in von Kossa staining rather than the RA. ALP activity showed significant increases on day 7 and subsequently its activity dropped to a lower level. Conclusion: The results showed that the 2-DG acted as a radiosensitizing agent and QCT acted as a radiosensitizing agent respectively in the irradiated MC3T3-E1 osteoblast-like cells.

• Natural Product Sciences
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• v.11 no.2
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• pp.103-108
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• 2005

Bioflavone quercetin is thought to have an important role to inhibit bone loss by affecting osteoclastogenesis and regulating a number of systemic and local factors such as hormones and cytokines. In this study, we examined how quercetin acts on cytokine production and mineralization of osteoblast in the presence of tumor necrosis factor-alpha $(TNF-{\alpha})$ which has been known to play a pivotal role in bone metabolic diseases. Quercetin inhibited $TNF-{\alpha}-induced$ secretion of $IFN-{\gamma}$ and IL-6 in differentiated MC3T3-E1 cells. As indicated by the markers that are characteristics of the osteoblast phenotype, such as alkaline phosphatase (ALP) activity and calcium deposition, quercetin treatment slightly prevented the $TNF-{\alpha}-induced$ dramatic inhibition of differentiation and mineralization of MC3T3-E1 cells. Further, quercetin inhibited the production of nitric oxide induced by $TNF-{\alpha}$ in the cells. Collectively, our findings indicate that quercetin inhibites $TNF-{\alpha}-induced$ secretion of inflammatory cytokines in differentiated MC3T3-E1 cells without any cytotoxic effects.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.4
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• pp.1-15
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• 2018

Objectives: Osteoporosis is considered a serious human disease. We developed an extract of mixed herbs containing root of Platycodon grandiflorum (ExMH-PGR), which is expected to be effective in preventing or treating osteoporosis. The aim of this study was to investigate the anti-osteoporotic effect of ExMH-PGR in osteoblastic MC3T3-E1 cells and osteoclastic RAW 264.7 cells. Methods: To examine the anti-osteoporotic effect of ExMH-PGR, osteoblast and osteoclast differentiation were induced and cultured with various concentrations of ExMH-PGR. Alkaline phosphatase (ALP) activity, collagen synthesis, osteocalcin production, and mineralization in MC3T3-E1 cells were analyzed. Tartrate-resistant acid phosphatase (TRAP) activity and the formation of actin ring in RAW 264.7 cells were analyzed. Results: ExMH-PGR at concentration up to $25{\mu}g/mL$ significantly increased ALP activity, collagen synthesis, osteocalcin production, and mineralization in MC3T3-E1 cells. ExMH-PGR at 50 to $200{\mu}g/mL$ significantly inhibited TRAP activity and the formation of actin ring in RAW 264.7 cells. Conclusions: These results demonstrate that ExMH-PGR stimulates osteoblastic activities and inhibits osteoclastic activities in in vitro systems, suggesting that ExMH-PGR might be considered as an anti-osteoporotic candidate for treatment of osteoporosis disease.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.415-423
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• 2009

The purpose of this study is to investigate the response of human pulp cell on Portland cement mixed with $\beta$-glycerophosphate. To investigate the effect of $\beta$-glycerophosphate and/or dexamethasone on human pulp cell, ALP activity on various concentration of $\beta$-glycerophosphate and dexamethasone was measured and mineral nodule of human pulp cell was stained with Alizarin red S. MTS assay and ALP activity of human pulp cell on Portland cement mixed with various concentration of $\beta$-glycerophosphate (10 mM, 100mM, 1M) was measured and the specimens were examined under SEM. Addition of $\beta$-glycerophosphate or dexamethasone alone had no effect however, the addition of 5 mM $\beta$-glycerophosphate and 100 nM dexamethasone had the largest increasement in ALP activity. There was no toxicity in all samples and the data showed that Portland cement mixed with 10 mM $\beta$-glycerophosphate had more increase in ALP activity compared with control. In conclusion, Portland cement mixed with $\beta$-glycerophosphate has no toxicity and promotes differentiation and mineralization of pulp cell compared with additive-free Portland cement. This implicated that application of Portland cement mixed with $\beta$-glycerophosphate might form more reparative dentin and in turn it would bring direct pulp capping to success.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.6
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• pp.524-529
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• 2006

For the repairing of bone defect, autogenous or allogenic bone grafting remains the standard. However, these methods have numerous disadvantages including limited amount, donor site morbidity and spread of diseases. Tissue engineering technique by culturing stem cells may allow for a smart solution for this problem. Adipose tissue contains mesenchymal stem cells that can be differentiate into bone, cartilage, fat or muscle by exposing them to specific growth conditions. In this study, the authors procured the stem cell from buccal fat pad and differentiate them into osteoblast and are to examine the bone induction capacity. Buccal fat-derived cells (BFDC) were obtained from human buccal fat pad and cultured. BFDC were analyzed for presence of stem cell by immunofluorescent staining against CD-34, CD-105 and STRO-1. After BFDC were differentiated in osteogenic medium for three passages, their ability to differentiate into osteogenic pathway were checked by alkaline phosphatase (ALP) staining, Alizarin red staining and RT-PCR for osteocalcin (OC) gene expression. Immunofluorescent and biochemical assays demonstrated that BFDC might be a distinguished stem cells and mineralization was accompanied by increased activity or expression of ALP and OC. And calcium phosphate deposition was also detected in their extracelluar matrix. The current study supports the presence of stem cells within the buccal fat pad and the potential implications for human bone tissue engineering for maxillofacial reconstruction.

• Journal of Veterinary Science
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• v.24 no.5
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• pp.69.1-69.11
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• 2023

Background: Kalkitoxin (KT) is an active lipopeptide isolated from the cyanobacterium Lyngbya majuscula found in the bed of the coral reef. Although KT suppresses cell division and inflammation, KT's mechanism of action in vascular smooth muscle cells (VSMCs) is unidentified. Therefore, our main aim was to investigate the impact of KT on vascular calcification for the treatment of cardiovascular disease. Objectives: Using diverse calcification media, we studied the effect of KT on VSMC calcification and the underlying mechanism of this effect. Methods: VSMC was isolated from the 6 weeks ICR mice. Then VSMCs were treated with different concentrations of KT to check the cell viability. Alizarin red and von Kossa staining were carried out to examine the calcium deposition on VSMC. Thoracic aorta of 6 weeks mice were taken and treated with different concentrations of KT, and H and E staining was performed. Real-time polymerase chain reaction and western blot were performed to examine KT's effect on VSMC mineralization. Calcium deposition on VSMC was examined with a calcium deposition quantification kit. Results: Calcium deposition, Alizarin red, and von Kossa staining revealed that KT reduced inorganic phosphate-induced calcification phenotypes. KT also reduced Ca⁺⁺-induced calcification by inhibiting genes that regulate osteoblast differentiation, such as runtrelated transcription factor 2 (RUNX-2), SMAD family member 4, osterix, collagen 1α, and osteopontin. Also, KT repressed Ca²⁺-induced bone morphogenetic protein 2, RUNX-2, collagen 1α, osteoprotegerin, and smooth muscle actin protein expression. Likewise, Alizarin red and von Kossa staining showed that KT markedly decreased the calcification of ex vivo ring formation in the mouse thoracic aorta. Conclusions: This experiment demonstrated that KT decreases vascular calcification and may be developed as a new therapeutic treatment for vascular calcification and arteriosclerosis.