• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권2호
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• pp.118-125
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• 2010

Background and Purpose: Bone metastases rarely occur in patients with oral squamous cell carcinoma (OSCC), so the molecular mechanisms of bone metastasis of OSCC remains unclear. Studies with animal models allow progresses in understanding the molecular events for bone metastasis and provide new targets for therapy. So we tried to establish a murine model for bone metastasis of oral squamous cell carcinoma. Materials and Methods: Human OSCC cells (KB cell line) were xenografted to nude mice via direct inoculation into the tibial marrow. Mice with tibial tumors were sacrificed once a week, until seven weeks after the injection of human tumor cells. Growth of tibial tumors were observed by histology. Expression of TGF-$\beta$ and CXCR-4 in bone OSCC (experimental) and subcutaneous tumor (control) was also evaluated by immunohistochemical staining. Results: Bone OSCC was successfully induced by intra-tibial injection of KB cells. Tumor mass was developed in the marrow tissues of tibia and finally invade the endosteum of tibia. Immunohistochemical staining showed higher expression of TGF-$\beta$ in bone tumors than in subcutaneous tumors. Conclusion: A murine model of bone metastasis of OSCC was suggested that imitated the clinical findings of distant vascular metastasis. This bone tumor model should facilitate understanding of the molecular pathogenesis of OSCC bone metastasis, and aid in the developement of treatment strategies against OSCC bone metastasis.

• Journal of Periodontal and Implant Science
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• 제53권6호
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• pp.467-477
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• 2023

Purpose: The purpose of this study was to evaluate the regenerative capacity of stem cells combined with bone graft material and a collagen matrix in rabbit calvarial defect models according to the type and form of the scaffolds, which included type I collagen matrix and synthetic bone. Methods: Mesenchymal stem cells (MSCs) were obtained from the periosteum of participants. Four symmetrical 6-mm-diameter circular defects were made in New Zealand white rabbits using a trephine drill. The defects were grafted with (1) group 1: synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×10⁵ MSCs; (2) group 2: collagen matrix and 1×10⁵ MSCs; (3) group 3: β-TCP/HA, collagen matrix covering β-TCP/HA, and 1×10⁵ MSCs; or (4) group 4: β-TCP/HA, chipped collagen matrix mixed with β-TCP/HA, and 1×10⁵ MSCs. Cellular viability and cell migration rates were analyzed. Results: Uneventful healing was achieved in all areas where the defects were made at 4 weeks, and no signs of infection were identified during the healing period or at the time of retrieval. New bone formation was more evident in groups 3 and 4 than in the other groups. A densitometric analysis of the calvarium at 8 weeks post-surgery showed the highest values in group 3. Conclusions: This study showed that the highest regeneration was found when the stem cells were applied to synthetic bone along with a collagen matrix.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.109-109
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• 2003

Taurine is present in a variety of tissue and exhibits many important physiological functions in many tissues. Although it is known that many tissues mediate taurine transport, its functions of taurine transport in bone have not been identified yet. In the present study, we investigated the expression of taurine transporter (TauT) and taurine uptake using mouse stromal ST2 cells and osteoblast-like MC3T3-El cells, which is bone related cells. Detection of TauT mRNA expression in these cells were performed by reverse transcription polymerase chain reaction (RT-PCR). The activity of TauT was assessed by measuring the uptake of ［$^3$H］taurine in the presence or absence of inhibitors. TauT mRNA was detected in these cells. ［$^3$H］Taurine uptake was dependent upon the presence of extracellular sodium, chloride and calcium ions, and inhibited by cold-taurine and ${\beta}$-alanine. These results suggest that taurine has biological functions in bone and some effect on the bone cells.

• Biomolecules & Therapeutics
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• 제24권1호
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• pp.9-18
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• 2016

Bone matrix is properly maintained by osteoclasts and osteoblasts. In the tumor microenvironment, osteoclasts are increasingly differentiated by the various ligands and cytokines secreted from the metastasized cancer cells at the bone metastasis niche. The activated osteoclasts generate osteolytic lesions. For this reason, studies focusing on the differentiation of osteoclasts are important to reduce bone destruction by tumor metastasis. The N-myc downstream-regulated gene 2 (NDRG2) has been known to contribute to the suppression of tumor growth and metastasis, but the precise role of NDRG2 in osteoclast differentiation induced by cancer cells has not been elucidated. In this study, we demonstrate that NDRG2 expression in breast cancer cells has an inhibitory effect on osteoclast differentiation. RAW 264.7 cells, which are monocytic preosteoclast cells, treated with the conditioned media (CM) of murine breast cancer cells (4T1) expressing NDRG2 are less differentiated into the multinucleated osteoclast-like cells than those treated with the CM of 4T1-WT or 4T1-mock cells. Interestingly, 4T1 cells stably expressing NDRG2 showed a decreased mRNA and protein level of intercellular adhesion molecule 1 (ICAM1), which is known to enhance osteoclast maturation. Osteoclast differentiation was also reduced by ICAM1 knockdown in 4T1 cells. In addition, blocking the interaction between soluble ICAM1 and ICAM1 receptors significantly decreased osteoclastogenesis of RAW 264.7 cells in the tumor environment. Collectively, these results suggest that the reduction of ICAM1 expression by NDRG2 in breast cancer cells decreases osteoclast differentiation, and demonstrate that excessive bone resorption could be inhibited via ICAM1 down-regulation by NDRG2 expression.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.448-468
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• 1996

To maintain its functional integrity, bone is continuously remodelled by a process involving resorption by osteoeclasts and formation by osteoblasts, In order to respond to changes in the physical environment or to trauma with the relevant action, this process is strictly regulated by locally synthesized or systemic fators, Prostaglandin $E_2(PGE_2$) is perhaps one of the best studied factors, having been known to affect bone cell function for several decades.$PGE_2$ has both anabolic and catabolic activities. Excess of $PGE_2$ has been implicated in a number of pathological states associated with bone loss in a number of chronic inflammatory conditions such as periodontal disease and rheumatoid arthritis. $PGE_2$ and other arachidonic acid metabolites have been shown to be potent stimulators of osteoclastic bone resorption in organ culture. The anabolic effects of $PGE_2$ were first noticed when an increase in periosteal woven bone formation was seen after the infusion of $PGE_2$ into infants in order to prevent closure of the ductus arteriosus. The cellular basis for the catabolic actions of $PGE_2$ has been well characterized. $PGE_2$increases osteoclast recruitment in bone marrow cell cultures. Also $PGE_2$ has a direct action on osteoclast serving to inhibit activity and can also indirectly activate osteoclast via other cells in the vicinity, presumably osteoblast. The cellular mechanisms for the anabolic actions of $PGE_2$ are not nearly so well understood. The purpose of this paper was to study the effects of $PGE_2$ and dibutyl(DB)cAMP on osteoblastic clone MC3T3El cells and on the generation of osteoclasts from their precursor cells. The effect of $PGE_2$ and DBcAMP on the induction of alkaline phoaphatase(AlP) was investigated in osteoblastic clone MC3T3El cells cultured in medium containing 0.4% fetal bovine serum. $PGE_2$ and DBcAMP stimulated ALP activity and MTT assay in the cells in a dose-dependent manner at concentrations of lO-SOOng/ml. Cycloheximide, protein synthesis inhibitor, inhibited the stimulative effect of $PGE_2$ and DBcAMP on ALP activity in the cells. $PGE_2$also increased the intracellular cAMP content in a dose-dependent fashion with a maximal effect at 500ng/ml. The effect of $PGE_2$ on the generation of osteoclasts was investigated in a coculture system of mouse bone marrow cells with primary osteoblastic cells cultured in media containing 10% fetal bovine serum.After cultures, staining for tartrate-resistant acid phosphatase(TRAP)-marker enzyme of osteoclast was performed. The TRAP(+) multinucleated cells(MNCs), which have 3 or more nuclei, were counted. More TRAP(+) MNCs were formed in coculture system than in control group. $PGE_2(10^{-5}10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in culture. $PGE_2(10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in coculture of osteoblastic clone MC3T3E1 cells This results suggest that $PGE_2$ stimulates the differentiation of osteoblasts and generation of osteoclast, and are involved in bone formation, as well as in bone resorption.

• Journal of Gastric Cancer
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• 제6권4호
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• pp.221-226
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• 2006

목적: 암 환자의 골수에서 발견되는 cytokeratin 양성세포와 암의 재발과의 상관관계에 대해서는 알려진 바가 많지 않다. 이에 위암환자의 골수에서 발견되는 cytokeratin 양성세포가 위암 환자의 재발과 생존율을 예측할 수 있는지 알아보고자 하였다. 대상 및 방법: 1998년 6월부터 2000년 7월까지 경북대학교병원 외과에서 원발성 위암으로 수술받은 환자 419명을 대상으로 하였다. 수술 직전 장골능선에서 골수를 흡인하여 단핵구를 분리하고 항 cytokeratin 항체를 이용하여 면역세포화학적 염색을 하였다. 결과: Cytokeratin 양성세포는 219예(52.4%)에서 발견되었고, 위암의 침윤깊이(P=0.021), 병기(P=0.026)에 따라서 통계학적으로 유의한 차이가 있었으나, 암의 위치, 육안형, 림프절전이, 원격전이, 분화도에 따라서는 유의한 차이가 없었다. 골수의 cytokeratin 양성세포 유무에 따른 5년 생존율은 유의한 차이가 없었고(P=0.248), 재발여부, 재발부위도 유의한 차이가 없었다. 결론: 위암 환자의 골수에서 cytokeratin 양성세포 유무는 예후인자로 사용되기 어렵고 재발양상을 예측하기도 어렵다.

• 한국재료학회지
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• 제20권6호
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• pp.312-318
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• 2010

Multilayer Poly methyl methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates were fabricated using electrospinning and in vitro investigations were carried out for pre-clinical biocompatibility studies. The initial cellular cytotoxicity of the methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using fibroblast-like L-929 cells. Cellular adhesion and differentiation studies were carried out using osteoblast-like MG-63 cells. As simulated body fluid (SBF) contains the same ionic concentration of body fluid and any bioactive material tends to deposit bone-like apatite on the samples surfaces into the SBF, in vitro bioactivity of the multilayer bone plates were investigated using SBF. We also studied the internal organization and tensile strength of the multilayer PMMA/PVA bone plates using micro-computed topography (${\mu}$-CT) and universal testing instrument (UTI, Korea) respectively. The cellular cytotoxicity study with MTT confirmed that the cellular viability was 78 to 90% which indicates good cyto-compatibility. Scanning electron microscopic findings revealed a good attachment and adhesion phenomenon of MG-63 cells onto the surfaces of the samples. Cellular differentiation studies also showed that osteogenic differentiation was switched on in a timely manner and affirmed along with that of the control group. Bone-like apatite formation on the surfaces was confirmed within 14 days of SBF incubation. Initial organizations of the multilayer PMMA/PVA bone plates were characterized as dense and uniform. The tensile strength of the post-pressing electronspun mat was higher than that of the pre-electronspun mat. These results suggest that a multilayer PMMA/PVA bone plate system is biocompatible, bioactive and a very good alternative bone plate system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권5호
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• pp.380-390
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• 2004

Bone healing plays an important role in orthognathic and craniofacial surgery. Bone tissue repair and regeneration are regulated by an array of growth and morphogenetic factors. Bone formation and remodeling require continuous generation of osteoprogenitor cells from bone marrow stromal cells, which generate and respond to a variety of growth factors with putative roles in hematopoiesis and mesenchymal differentiation. In this study, the efficacy of a single application of hepatocyte growth factor to promote bone regeneration in 5-mm experimental calvarial defects of adult male rats was assessed histologically and immunohistochemically. The result of the experimental site were compared with those of the contralateral contral side. None of the control and experimental bone defects demonstrated complete bone closure. Bone regeneration was found close th the margine and central part of the defects. At 1, 2 weeks, there were found much significant cellural mitotic activity and many inflammatory cells and osteoblasts on the experimental site than control site. At 4, 6 weeks, new bone apposition was founded in both site but, more apposition was seen at experimental site. At 8, 12 weeks, also, some differences was found that more apposition of new bone and collagen fiber was seen on experimental site. Our results have some possibility that HGF do a early positive role to repair the bone defect. More study will be needed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권6호
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• pp.397-402
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• 2009

The purpose of this study is to investigate the effects of alendronate and pamidronate on proliferation and the alkaline phosphatase activity of human bone marrow derived mesenchymal stem cells and to relate the results with bisphosphonate related osteonecrosis of the jaw(BRONJ). With the consent of patients with no systemic disease and undergoing iliac bone graft, cancellous bone was collected to obtain human bone marrow derived mesenchymal stem cells through cell culture. 96 well plate were prepared with a concentration of $10^4$cell/ well. Alendronate and pamidronate were added to each well with the concentration of $10^{-6}M$, $10^{-8}M$ and $10^{-10}M$, respectively. Then proliferation capacity of each well was evaluated with the cell counting kit. 24 well plates were prepared with a concentration of $10^5$cell/ml/well and with the bone supplement, alendronate and pamidronate were added with the concentration of $10^{-6}M$, $10^{-8}M$ and $10^{-10}M$, respectively on each plate. The plates were cultured for either 24 or 72 hours. Then the cells were sonicated to measure the alkaline phosphatase activity and protein assay was done to standardize the data for analysis. As the concentration of alendronate or pamidronate added to the culture increased, the proliferation capacity of the cells decreased. However, no statistical significance was found between the group with $10^{-10}M$ of bisphophonate and the control group. Pamidronate was not capable of increasing the alkaline phosphatase activity in all trials. However, alkaline phosphatase activity increased with 24 hours of $10^{-8}M$ of alendronate treatment and with 48 hours of $10^{-10}M$ of alendronate treatment. Cell toxicity increased as the bisphosphonate concentration increased. This seems to be associated with the long half life of bisphosphonate, resulting in high concentration of bisphosphonate in the jaw and thus displaying delayed healing after surgical procedures. Alendronate has shown to increase the alkaline phophatase activity of human bone marrow derived mesenchymal stem cells. However, this data is insufficient to conclude that alendronate facilitates the differentiation of human bone marrow derived mesenchymal stem cells. Further studies on DNA level and animal studies are required to support these results.

• Biomolecules & Therapeutics
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• 제11권2호
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• pp.81-84
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• 2003

Recently, diabetes has been found to be associated with osteoporosis. Specially in IDDM. In both type I and type II diabetes, glucose levels are elevated. Thus, a linkage between high glucose and osteoporosis can not be ruled out. In this study, an attempt has been made to observe the effect of high glucose on bone formation; osteoblast like UMR 106 cells were treated with high glucose (22 mM, 33 mM) for 1, 3 or 7 days. The high concentration of glucose inhibited markers. of bone formation activity such as alkaline phosphatase and collagen synthesis. In addition, reduction in the level of total cellular protein in response to high glucose was also observed. This study showed high glucose concentration could alter the bone metabolism leading to a defective bone formation and thus paving the linkage of such situation to diabetic complications.