• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2320-2327
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• 2020

The extreme hydrophobicity of expanded polytetrafluoroethylene (ePTFE) hinders bone-tissue integration, thus limiting the use of ePTFE in medical implant applications. To improve the potential of ePTFE as a biomaterial, 2-hydroxyethyl methacrylate (HEMA) was grafted onto the ePTFE surface using the gamma irradiation technique. The characteristics of the grafted ePTFE were successfully evaluated using attenuated total reflectance Fourier transform infrared (ATR-FTIR), field-emission scanning electron microscopy (FESEM)/energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). Under the tensile test, the modified ePTFE was found to be more brittle and rigid than the untreated sample. In addition, the grafted ePTFE was less hydrophobic with a higher percentage of water uptake compared to the untreated ePTFE. The protein adsorption test showed that grafted ePTFE could adsorb protein, which was denoted by the presence of N peaks in the XPS analysis. Moreover, the formation of the globular mineral on the grafted ePTFE surface was successfully visualized using the FESEM analysis, with a ratio of 1.94 for Ca:P minerals by the EDX. To summarize, the capability of the modified ePTFE to show protein adsorption and mineralization indicates the improvement of the polymer properties, and it can potentially be used as a biomaterial for implant application.

• Molecules and Cells
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• 제40권3호
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• pp.211-221
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• 2017

Transforming growth factor ${\beta}1$ $(TGF{\beta}1)/Smad4$ signaling plays a pivotal role in maintenance of the dynamic balance between bone formation and resorption. The microRNA miR-155 has been reported to exert a significant role in the differentiation of macrophage and dendritic cells. The goal of this study was to determine whether miR-155 regulates osteoclast differentiation through $TGF{\beta}1/Smad4$ signaling. Here, we present that $TGF{\beta}1$ elevated miR-155 levels during osteoclast differentiation through the stimulation of M-CSF and RANKL. Additionally, we found that silencing Smad4 attenuated the upregulation of miR-155 induced by $TGF{\beta}1$. The results of luciferase reporter experiments and ChIP assays demonstrated that $TGF{\beta}1$ promoted the binding of Smad4 to the miR-155 promoter at a site located in 454 bp from the transcription start site in vivo, further verifying that miR-155 is a transcriptional target of the $TGF{\beta}1/Smad4$ pathway. Subsequently, TRAP staining and qRT-PCR analysis revealed that silencing Smad4 impaired the $TGF{\beta}1$-mediated inhibition on osteoclast differentiation. Finally, we found that miR-155 may target SOCS1 and MITF to suppress osteoclast differentiation. Taken together, we provide the first evidence that $TGF{\beta}1/Smad4$ signaling affects osteoclast differentiation by regulation of miR-155 expression and the use of miR-155 as a potential therapeutic target for osteoclast-related diseases shows great promise.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.317-332
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• 2001

The purpose of this study was to investigate effects of the natural coral(NC) and the hydroxyapatite/calcium sulfate hemihydrate(HA/CS) on an early stages of wound healing in the rat periodontal fenestration defects. In this experiment, twelve male rats(Mean : 520g in BW) aged 8 to 9 months were used. Experimental periodontal fenestration defects were surgically created with tapered fissure bur at the buccal surface of the left mandibular 1st, 2nd molars. The buccal aspects of molar roots were carefully denuded of their periodontal ligament through a bony window created in the left mandibles of rats under general anesthesia. Each experimental periodontal fenestration defect was grafted with natural coral and HA/CS, randomly. An area without bone graft was assigned for negative control group. At 10,35 days, rats were serially sacrificed via intracardiac perfusion with 2.5% glutaraldehyde and specimens were processed with Hematoxylin-Eosin stain for light microscopic evaluation. The results of this study were as follows : 1. The defect areas were filled with dense connective tissues at 10 days in control group. But in the test(NC, HA/CS)groups, the connective tissues around graft materials were formed more loosely and the response of inflammation by graft materials itself was not found. 2. The defect areas were filled with new osteoid tissues and new cementum was not formed on the cut root surface at 35 days in the control group. 3. New osteoid tissue formation was more prominent at 35 days in control than test groups. 4. The NC and HA/CS particles were encapsulated by loose connective tissues at 10 days and by dense connective tissues at 35 days, respectively. 5. In the test groups, resorption of graft particles was not found through the experimental time. From the above results, natural coral and hydroxyapatite/calcium sulfate hemihydrate may be biocompatible and osteoconductive and have a weak adverse reaction to the periodontal tissues.

• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.453-462
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• 2020

Chronic joint pain due to loss of cartilage function, degradation of subchondral bone, and related conditions are common plights of an arthritis patient. Antioxidant compounds could solve the problems in arthritic condition. The objective of this study was to evaluate the anti-arthritic activity of D-carvone against complete Freund's adjuvant (CFA)-induced arthritis in rats. D-carvone was orally administered for 25 days at the doses of 30 and 60 mg/kg against CFA-induced arthritic rats. Changes in body weight, paw swelling, organ index, hematological parameters, oxidative stress markers, inflammatory cytokines, and histopathology were recorded. Oral treatment of D-carvone significantly improved the body weight, reduced the paw swelling, edema formation, and organ index in arthritic rats. The levels of white blood cells were reduced, red blood cells and hemoglobin levels were improved in D-carvone treated arthritic rats. Lipid peroxidation levels were lowered whereas enzymatic and non-enzymatic antioxidants were significantly elevated by D-carvone administration against arthritic rats. D-carvone significantly modulated inflammatory cytokine levels and improved the ankle joint pathology against CFA-induced arthritic inflammation. In conclusion, D-carvone proved significant anti-arthritic activity against CFA-induced arthritis in rats.

• 한국학교ㆍ지역보건교육학회지
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• 제6권
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• pp.109-115
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• 2005

A survey was performed for 528 college students who are faced at a period of bone formation from Oct. 10 to Oct. 15, 2005 in order to investigate health promotion behaviors by the perceived benefit in diets and exercises and level of the self-efficacy and to extract certain directions to facilitate the level of health promotion behaviors in diets and exercises to prevent osteoporosis by investigating the correlation between these factors. 1. There are some differences in the health promotion behavior for each group according to the sex, grade, and majoring. 2. There are no significant differences between the perceived benefit in diets and exercises according to the health promotion behavior, and the self-efficacy in diets presented certain high levels in the group that presented a high level of health promotion behaviors (3.4744) than that of the group that presented a low level of health promotion behaviors(3.2099). In addition, the self-efficacy in exercises presented certain high levels in the group that presented a high level of health promotion behaviors(3.7528) than that of the group that presented a low level of health promotion behaviors(3.3085). 3. The most important factor that affects 'Health promotion behaviors in diets' was 'Self-efficacies in diets' rather than that of 'Perceived benefits in diets'. The important factor that affects 'Health promotion behaviors in exercises' was 'Self-efficacies in exercises' rather than that of 'Perceived benefits in exercises'.

• 한국재료학회지
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• 제19권7호
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• pp.362-368
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• 2009

Ti scaffolds with a three-dimensional porous structure were successfully fabricated using powder metallurgy and modified rapid prototyping (RP) process. The fabricated Ti scaffolds showed a highly porous structure with interconnected pores. The porosity and pore size of the scaffolds were in the range of 66$\sim$72% and $300\sim400\;\mu$m, respectively. The sintering of the fabricated scaffolds under the vacuum caused the Ti particles to bond to each other. The strength of the scaffolds depended on the layering patterns. The compressive strength of the scaffolds ranged from 15 MPa to 52 MPa according to the scaffolds' architecture. The alkali treatment of the fabricated scaffolds in an aqueous NaOH solution was shown to be effective in improving the bioactivity. The surface of the alkali-treated Ti scaffolds had a nano-sized fibre-like structure. The modified surface showed a good apatite forming ability. The apatite was formed on the surface of the alkali treated Ti scaffolds within 1 day. The thickness of the apatite increased when the soaking time in a simulated body fluid (SBF) solution increased. It is expected that the surface modification of Ti scaffolds by alkali treatment could be effective in forming apatites in vivo and can subsequently enhance bone formation.

• International Journal of Stem Cells
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• 제11권2호
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• pp.177-186
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• 2018

Background and Objectives: Glial scarring and inflammation after spinal cord injury (SCI) interfere with neural regeneration and functional recovery due to the inhibitory microenvironment of the injured spinal cord. Stem cell transplantation can improve functional recovery in experimental models of SCI, but many obstacles to clinical application remain due to concerns regarding the effectiveness and safety of stem cell transplantation for SCI patients. In this study, we investigated the effects of transplantation of human mesenchymal stem cells (hMSCs) that were genetically modified to express Olig2 in a rat model of SCI. Methods: Bone marrow-derived hMSCs were genetically modified to express Olig2 and transplanted one week after the induction of contusive SCI in a rat model. Spinal cords were harvested 7 weeks after transplantation. Results: Transplantation of Olig2-expressing hMSCs significantly improved functional recovery in a rat model of contusive SCI model compared to the control hMSC-transplanted group. Transplantation of Olig2-expressing hMSCs also attenuated glial scar formation in spinal cord lesions. Immunohistochemical analysis showed that transplanted Olig2-expressing hMSCs were partially differentiated into Olig1-positive oligodendrocyte-like cells in spinal cords. Furthermore, NF-M-positive axons were more abundant in the Olig2-expressing hMSC-transplanted group than in the control hMSC-transplanted group. Conclusions: We suggest that Olig2-expressing hMSCs are a safe and optimal cell source for treating SCI.

• The Korean Journal of Physiology and Pharmacology
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• 제25권2호
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• pp.139-146
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• 2021

Mitochondrial NADP+-dependent isocitrate dehydrogenase 2 (IDH2) produces NADPH, which is known to inhibit mitochondrial oxidative stress. Ureteral obstruction induces kidney inflammation and fibrosis via oxidative stress. Here, we investigated the role and underlying mechanism of IDH2 in unilateral ureteral obstruction (UUO)-induced kidney inflammation using IDH2 gene deleted mice (IDH2-/-). Eight- to 10-week-old female IDH2-/- mice and wild type (IDH2+/+) littermates were subjected to UUO and kidneys were harvested 5 days after UUO. IDH2 was not detected in the kidneys of IDH2-/- mice, while UUO decreased IDH2 in IDH2+/+ mice. UUO increased the expressions of markers of oxidative stress in both IDH2+/+ and IDH2-/- mice, and these changes were greater in IDH2-/- mice compared to IDH2+/+ mice. Bone marrow-derived macrophages of IDH2-/- mice showed a more migrating phenotype with greater ruffle formation and Rac1 distribution than that of IDH2+/+ mice. Correspondently, UUO-induced infiltration of monocytes/macrophages was greater in IDH2-/- mice compared to IDH2+/+ mice. Taken together, these data demonstrate that IDH2 plays a protective role against UUO-induced inflammation through inhibition of oxidative stress and macrophage infiltration.

• 대한두개안면성형외과학회지
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• 제22권6호
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• pp.310-318
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• 2021

Background: Transcutaneous lower eyelid approaches are associated with a risk of postoperative scarring depending on the distance between the incision line and the lower eyelid margin. The lower eyelid crease of Caucasians corresponds to a ridge-shaped fold in young Asians. However, this relationship has not been sufficiently evaluated in the latter. The authors, therefore, investigated the location of the scar and the lower eyelid crease or ridge to find the optimal location for the incision line. Methods: This study included 60 out of 139 patients who underwent inferior orbital wall reconstruction through a lower eyelid skin incision between July 2019 and June 2020. According to the location of the scar, the patients were classified into three groups: group A (≥ 2 mm above the lower eyelid crease or ridge), group B (within the lower eyelid crease or ridge to 2 mm above the lower eyelid crease or ridge), and group C (within the lower eyelid crease or ridge to 2 mm below the lower eyelid crease or ridge). At 6 or 12 months after surgery, the Patient and Observer Scar Assessment Scale (POSAS) score was obtained, the distance between the lower eyelid margin and the scar (DMS) and the distance between the margins of the peripheral pupil and the lower eyelid (DMPE) were measured, and the occurrence of ectropion was evaluated. Results: Group B had the lowest POSAS score (A: 22.7 ± 8.0, B: 20.9 ± 2.4, C: 32.5 ± 4.1, p< 0.001). Linear regression analysis showed that the DMS was positively correlated with the POSAS score (p< 0.001) and that the risk of DMPE widening increased as the DMS decreased (p= 0.029). None of the patients had ectropion. Conclusion: When using the transcutaneous approach for inferior orbital wall reconstruction, the optimal incision site is within the lower eyelid crease or ridge to 2 mm above the lower eyelid crease or ridge.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제49권2호
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• pp.68-74
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• 2023

Objectives: Drug holidays are suggested to reduce the formation of osteonecrosis in patients under intravenous (IV) bisphosphonates (BPs) therapy. The objectives of this study are to evaluate the incidence of medication-related osteonecrosis of the jaw (MRONJ) following tooth extraction in cancer patients using IV BP, and to assess the effect of drug holiday on the development of MRONJ. Patients and Methods: A manuel search of the patient folders of Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Hacettepe University was undertaken to identify cancer patients who used IV BPs and had at least one tooth extraction between 2012 and 2022. Patents' age, sex, systemic condition, the type of BP used, duration of BP used, number of tooth extraction, duration of drug holiday, localization of tooth extraction and incidence of MRONJ were recorded. Results: One hundred nine teeth were removed from 57 jaws in 51 patients. All tooth extractions were performed under perioperative antibiotic prophylaxis and with primary wound closure. The incidence of MRONJ was 5.3%. Stage 1 MRONJ developed in 3 patients (only one had a drug holiday). The median duration of drug holiday was 2 months. No significant difference between the patients with and without a drug holiday and MRONJ development was found (P=0.315). The mean age of patients developed MRONJ was 40.33±8.08 years. A statistically significant difference was found between age and MRONJ development (P=0.002). Conclusion: The effect of a short-term drug holiday on the development of MRONJ may be limited because BPs remain in bone tissue for a long time. Drug holidays should be applied with the approval of an oncologist with other preventive measurements.