• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.79-79
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• 2017

Metallic biomaterials have been mainly used for the fabrication of medical devices for the replacement of hard tissue such as artificial hip joints, bone plates, and dental implants. Because they are very reliable on the viewpoint of mechanical performance. This trend is expected to continue. Especially, Ti and Ti alloys are bioinert. So, they do not chemically bond to the bone, whereas they physically bond with bone tissue. For their poor surface biocompatibility, the surface of Ti alloys has to be modified to improve the surface osteoinductivity. Recently, ceramic-like coatings on titanium, produced by plasma electrolytic oxidation (PEO), have been developed with calciumand phosphorus-enriched surfaces. A lso included the influences of coatings, which can accelerate healing and cell integration, as well as improve tribological properties. However, the adhesions of these coatings to the Ti surface need to be improved for clinical use. Particularly Silicon (Si) has been found to be essential for normal bone, cartilage growth and development. This hydroxyapatite, modified with the inclusion of small concentrations of silicon has been demonstrating to improve the osteoblast proliferation and the bone extracellular matrix production. Strontium-containing hydroxyapatite (Sr-HA) was designed as a filling material to improve the biocompatibility of bone cement. In vitro, the presence of strontium in the coating enhances osteoblast activity and differentiation, whereas it inhibits osteoclast production and proliferation. The objective of this work was to study Morphology of bone-like apatite formation on Sr and Si-doped hydroxyapatite surface of Ti-6Al-4V alloy after plasma electrolytic oxidation. Anodized alloys was prepared at 270V~300V voltages with various concentrations of Si and Sr ions. Bone-like apatite formation was carried out in SBF solution. The morphology of PEO, phase and composition of oxide surface of Ti-6Al-4V alloys were examined by FE-SEM, EDS, and XRD.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.154-154
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• 2017

Ti-6Al-4V alloys are widely used as metal-lic biomaterials in dentistry and orthopedics due to its excellent biocompatibility and me-chanical properties. However, because of low biological activity, it is difficult to form bone growth directly on the surface of titanium implants. For this reason, surface treatment of plasma electrolytic oxidation(PEO) was used for dental implants. To enhance bioac-tivity on the surface, strontium(Sr) and sili-con(Si) ions can be added to PEO treated sur-face in the electrolyte containing these ions. The presence of Sr in the coating enhances osteoblast activity and differentiation, where-as it inhibits osteoclast production and prolif-eration. And Si has been found to be essen-tial for normal bone, cartilage growth, and development. In this study, electrochemical characteristics of Ca, P, Sr, and Si ions from PEO-treated Ti-6Al-4V alloy surface was re-searched using various experimental instruments. DC power is used and Ti-6Al-4V al-loy was subjected to a voltage of 280 V for 3 minutes in the electrolyte containing 5, 10, 20M% Sr ion and 5M% Si ion. The morphol-ogies of PEO-treated Ti-6Al-4V alloy by electrochemical anodization were examined by field-emission scanning electron micro-scopes (FE-SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and corrosion analysis using AC impedance and potentiodynamic polarization test in 0.9% NaCl solution at similar body tempera-ture using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

• The Korean Journal of Pain
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• 제30권2호
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• pp.86-92
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• 2017

Osteoblasts, originating from mesenchymal cells, make the receptor activator of the nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in order to control differentiation of activated osteoclasts, originating from hematopoietic stem cells. When the RANKL binds to the RANK of the pre-osteoclasts or mature osteoclasts, bone resorption increases. On the contrary, when OPG binds to the RANK, bone resorption decreases. Denosumab (AMG 162), like OPG (a decoy receptor), binds to the RANKL, and reduces binding between the RANK and the RANKL resulting in inhibition of osteoclastogenesis and reduction of bone resorption. Bisphosphonates (BPs), which bind to the bone mineral and occupy the site of resorption performed by activated osteoclasts, are still the drugs of choice to prevent and treat osteoporosis. The merits of denosumab are reversibility targeting the RANKL, lack of adverse gastrointestinal events, improved adherence due to convenient biannual subcutaneous administration, and potential use with impaired renal function. The known adverse reactions are musculoskeletal pain, increased infections with adverse dermatologic reactions, osteonecrosis of the jaw, hypersensitivity reaction, and hypocalcemia. Treatment with 60 mg of denosumab reduces the bone resorption marker, serum type 1 C-telopeptide, by 3 days, with maximum reduction occurring by 1 month. The mean time to maximum denosumab concentration is 10 days with a mean half-life of 25.4 days. In conclusion, the convenient biannual subcutaneous administration of 60 mg of denosumab can be considered as a first-line treatment for osteoporosis in cases of low compliance with BPs due to gastrointestinal trouble and impaired renal function.

• International Journal of Oral Biology
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• 제38권3호
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• pp.127-134
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• 2013

Xylitol is a sugar alcohol with a variety of functions including bactericidal and anticariogenic effects. However, the cellular mechanisms underlying the role of xylitol in bone metabolism are not yet clarified. In our present study, we exploited the physiological role of xylitol on osteoclast differentiation in a co-culture system of osteoblastic and RAW 264.7 cells. Xylitol treatment of these co-cultures reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells induced by 10 nM $1{\alpha},25(OH)_2D_3$ in a dose-dependent manner. A cell viability test revealed no marked cellular damage by up to 100 mM of xylitol. Exposure of osteoblastic cells to xylitol decreased RANKL, but not OPG, mRNA expression in the presence of $10^{-8}M$ $1{\alpha},25(OH)_2D_3$ in a dose-dependent manner. Furthermore, bone resorption activity, assessed on bone slices in the coculture system, was found to be dramatically decreased with increasing xylitol concentrations. RANKL and OPG proteins were assayed by ELISA and the soluble RANKL (sRANKL) concentration was decreased with an increased xylitol concentration. In contrast, OPG was unaltered by any xylitol concentration in this assay. These results indicate that xylitol inhibits $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis by reducing the sRANKL/OPG expression ratio in osteoblastic cells.

• Molecules and Cells
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• 제39권4호
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• pp.316-321
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• 2016

The receptor activator of nuclear factor ${\kappa}B$ (RANK) and its ligand RANKL are key regulators of osteoclastogenesis and well-recognized targets in developing treatments for bone disorders associated with excessive bone resorption, such as osteoporosis. Our previous work on the structure of the RANK-RANKL complex revealed that Loop3 of RANK, specifically the non-canonical disulfide bond at the tip, performs a crucial role in specific recognition of RANKL. It also demonstrated that peptide mimics of Loop3 were capable of interfering with the function of RANKL in osteoclastogenesis. Here, we reported the structure-based design of a smaller peptide with enhanced inhibitory efficiency. The kinetic analysis and osteoclast differentiation assay showed that in addition to the sharp turn induced by the disulfide bond, two consecutive arginine residues were also important for binding to RANKL and inhibiting osteoclastogenesis. Docking and molecular dynamics simulations proposed the binding mode of the peptide to the RANKL trimer, showing that the arginine residues provide electrostatic interactions with RANKL and contribute to stabilizing the complex. These findings provided useful information for the rational design of therapeutics for bone diseases associated with RANK/RANKL function.

• 한국해양바이오학회지
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• 제12권2호
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• pp.75-80
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• 2020

In the present study, the estrogenic activity and anti-osteoclastogenic activity of the Myelophycus simplex extract were evaluated using T47D-Kbluc cells and bone marrow-derived macrophages (BMMs). As a result of the measurement of the estrogenic activity in the T47D-Kbluc cell line, the Myelophycus simplex extract showed increased estrogenic activity in a dose-dependent manner in association with its concentration. To confirm the regulatory effect of the Myelophycus simplex extract on the estrogen-responsive gene, the Myelophycus simplex extract showed a similar tendency to estradiol: the expression of estrogen receptor 1 (ESR1) was significantly decreased while the expression of estrogen receptor 2 (ESR2) was increased. Furthermore, the Myelophycus simplex extract exhibited an inhibitory effect on osteoclast differentiation. In conclusion, these Myelophycus simplex extracts might be regarded as candidates for further studies or the development of functional food products or medicine to prevent or avoid postmenopausal symptoms for women.

• 대한본초학회지
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• 제37권5호
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• pp.1-8
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• 2022

Objectives : This study aimed to investigate the synergistic effect of combining Cynanchi Wilfordii Radix extract with Humuli Lupuli Flos extract on estrogenic and anti-osteoclastogenic activity. Methods : Estrogenic effect of a mixture of Cynanchi Wilfordii Radix extract and Humuli Lupuli Flos extract (CWHL), Cynanchi Wilfordii Radix extract, Humuli Lupuli Flos extract, caudatin (an active ingredient of Cynanchi wilfordii Radix extract) and 8-prenylnaringenin (an active ingredient of Humuli Lupuli Flos extract) were examined by proliferation E-screen assay and expression of estrogen inducible gene, pS2 via Real Time-PCR (RT-PCR) in MCF-7 estrogen responsive cells. And their estrogenic activities were investigated how to modulate Estrogen receptor 𝛽 by binding affinity assay. Inhibitory effect of CWHL, Cynanchi Wilfordii Radix extract, Humuli Lupuli Flos extract, caudatin and 8-prenylnaringenin on RANKL-induced osteoclast differentiation were tested by TRAP (Tartrate-resistant acid phosphatase) staining in osteoclastogenic RAW 264.7 cells. Results : CWHL, Humuli Lupuli Flos extract and 8-prenylnaringenin accelerated the proliferation of MCF-7 and the expression of pS2 in MCF-7. CWHL, Cynanchi Wilfordii Radix extract, Humuli Lupuli Flos extract, caudatin and 8-prenylnaringenin bind to estrogen receptor 𝛽. CWHL, Cynanchi Wilfordii Radix extract, Humuli Lupuli Flos extract, caudatin and 8-prenylnaringenin inhibited RANKL-induced osteoclastogenesis in osteoclastogenic RAW 264.7. CWHL is more effective for all markers than Cynanchi Wilfordii Radix extract or Humuli Lupuli Flos extract alone. Conclusions : CWHL may a potential therapeutic agent for menopause and osteoporosis as a natural food resource. CWHL as a natural food source has therapeutic potential in cases of menopause and osteoporosis.

• 대한소아치과학회지
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• 제27권2호
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• pp.309-317
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• 2000

본 실험은 bisphosphonate가 조골세포 분화 및 파골세포 분화에 미치는 영향을 알아보고자, etidronate와 alendronate를 조골세포에 투여하여 조골세포 전사인자인 Cbfa1, 조골세포 표시 인자의 발현, 석회화된 골결절 형성을 평가하였다. Bisphosphonate가 조골세포의 석회화된 골결절 형성에 미치는 영향을 평가하기 위하여 배양액에 $10^{-6},\;10^{-5},\;10^{-4}M$의 etidronate 및 $10^{-8},\;10^{-7},\;10^{-6}M$의 alendronate를 첨가하였으며, 배양 15일 후에 alizarin red로 염색하여 관찰하였다. 또 조골세포의 분화에 미치는 bisphosphonate의 영향을 평가하고자 백서 두개관에서 얻은 조골세포에 etidronate $10^{-6},\;10^{-5},\;10^{-4}M$ 및 alendronate $10^{-6}$ M을 투여하고 배양 8일 후 총RNA를 수집하였고, 전기영동 및 Northern blot hybridization하여 Cbfa1, alkaline phosphatase, type I collagen, osteopontin, osteocalcin의 발현을 조사하였다. 이상의 실험결과 다음과 같은 결론을 얻었다. 1. Etidronate는 농도 의존적으로 골결절 석회화를 억제하였으나, alendronate는 골석회화를 억제하지 않았다. 2. Etidronate는 Cbfa1의 발현을 농도 의존적으로 억제하였으나, alendronate는 오히려 촉진하였다. 3. Etidronate는 type I collagen, osteocalcin 및 osteopontin의 발현을 농도 의존적으로 억제하였으나, alendronate는 오히려 증가시켰다. 4. Alkaline phosphatase의 발현은 사용된 etidronate와 alendronate에 의해 영향 받지 않았다. 이상의 결과에서 etidironate는 조골세포의 전사인자인 Cbfa1의 발현을 억제하며, 이에 의하여 조골세포의 분화표지인자인 type I collagen, osteopontin 및 osteocalcin의 합성이 억제되고, 결과적으로 석회화된 골결절의 형성을 억제하는 것으로 사료된다.

• International Journal of Oral Biology
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• 제36권1호
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• pp.37-42
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• 2011

The working mechanism of bisphosphonate on bone cells is unclear despite its powerful inhibitory activity on bone resorption. The differentiation and activation of osteoclasts are essential for bone resorption and are controlled by the stimulatory RANKL and inhibitory OPG molecules. Teeth exhibit a range of movement patterns during their eruption to establish their form and function, which inevitably accompanies peripheral bone resorption. Hence, the mandible, which contains the teeth during their eruption processes, is a good model for revealing the inhibitory mechanism of bisphosphonate upon bone resorption. In the present study, RANKL and OPG expression were examined immunohistochemically in the mandible of rats with developing teeth after alendronate administration (2.5 mg/kg). The preeruptive mandibular first molars at postnatal days 3 to 10 showed the developing stages from bell to crown. No morphological changes in tooth formation were observed after alendronate administration. The number of osteoclasts in the alveolar bone around the developing teeth decreased markedly at postnatal days 3, 7 and 10 compared with the control group. RANKL induced strong positive immunohistochemical reactions in the dental follicles and stromal cells around the mandibular first molar. In particular, many osteoclasts with strongly positive reactions to RANKL appeared above the developing mandibular first molars at postnatal days 3 and 10. Immunohistochemical reactions with RANKL after alendronate administration were weaker than the control groups. However, the immunohistochemical reactivity to OPG was stronger after alendronate administration, at postnatal days 3 and 10. These results suggest that alendronate may decrease bone resorption by regulating the RANKL/OPG pathway in the process of osteoclast formation, resulting in a delay in tooth eruption.

• 한국발생생물학회지:발생과생식
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• 제18권4호
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• pp.197-212
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• 2014

Osteosarcoma (OS) is one of the most common malignant primary bone tumors and NF-${\kappa}B$ appears to play a causative role, but the mechanisms are poorly understood. OS is one of the pleomorphic, highly metastasized and invasive neoplasm which is capable to generate osteoid, osteoclast and osteoblast matrix. Its high incidence has been reported in adolescent and children. Cell signal cascade is the pivotal functional mechanism acquired during the differentiation, proliferation, growth and survival of the cells in neoplasm including OS. The major limitation to the success of chemotherapy in OS is the development of multidrug resistance (MDR). Answers to all such queries might come from the knock-in experiments in which the combined approach of miRNAs with NF-${\kappa}B$ pathway is put into use. Abnormal miRNAs can modulate several epigenetical switching as a hallmark of number of diseases via different cell signaling. Studies on miRNAs have opened up the new avenues for both the diagnosis and treatment of cancers including OS. Collectively, through the present study an attempt has been made to establish a new systematic approach for the investigation of microRNAs, bio-physiological factors and their target pairs with NF-${\kappa}B$ to ameliorate oncogenesis with the "bridge between miRNAs and NF-${\kappa}B$". The application of NF-${\kappa}B$ inhibitors in combination with miRNAs is expected to result in a more efficient killing of the cancer stem cells and a slower or less likely recurrence of cancer.