• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.146-154
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• 2009

In recent tissue engineering field, it is being reported that the fabrication of 3D scaffolds having high porous and controlled internal/external architectures can give potential contributions in cell adhesion, proliferation and differentiation. To fabricate these scaffolds, various solid free-form fabrication technologies are being applied. The solid free-form fabrication technology has made it possible to fabricate solid free-form 3D microstructures in layer-by-layer manner. In this research, we developed a multi-head deposition system (MHDS) and used design of experiment (DOE) to fabricate 3D scaffold having an optimized internal/external shape, Through the organization of experimental approach using DOE, the fabrication process of scaffold, which is composed of blended poly-caprolactone (PCL), poly-lactic-co-glycolic acid (PLGA) and tricalcium phosphate (TCP), is established to get uniform line width, line height and porosity efficiently Moreover, the feasibility of application to the tissue engineering of MHDS is demonstrated by human bone marrow stromal cells (hBMSCs) proliferation test.

• Biomolecules & Therapeutics
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• v.21 no.4
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• pp.264-269
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• 2013

Silymarin has been introduced fairly recently as a hepatoprotective agent. But its mechanisms of action still have not been well established. The aim of this study was to make alcoholic fatty liver model of rats in a short time and investigate silymarin's protective effects and possible mechanisms on alcoholic fatty liver for rats. The model of rat's alcoholic fatty liver was induced by intragastric infusion of ethanol and high-fat diet for six weeks. Histopathological changes were assessed by hematoxylin and eosin staining (HE). The activities of alanine transarninase (ALT) and aspartate aminotransferase (AST), the levels of total bilirubin (TBIL), total cholesterol (TC) and triglyceride (TG) in serum were detected with routine laboratory methods using an autoanalyzer. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and the level of malondialdehyde (MDA) in liver homogenates were measured by spectrophotometry. The TG content in liver tissue was determined by spectrophotometry. The expression of nuclear factor-${\kappa}B$ (NF-${\kappa}B$), intercellular adhesion molecule-1 (ICAM-1) and interleukin-6 (IL-6) in the liver were analyzed by immunohistochemistry. Silymarin effectively protected liver from alcohol-induced injury as evidenced by improving histological damage situation, reducing ALT and AST activities and TBIL level in serum, increasing SOD and GPx activities and decreasing MDA content in liver homogenates and reducing TG content in liver tissue. Additionally, silymarin markedly downregulated the expression of NF-${\kappa}B$ p65, ICAM-1 and IL-6 in liver tissue. In conclusion, Silymarin could protect against the liver injury caused by ethanol administration. The effect may be related to alleviating lipid peroxidation and inhibiting the expression of NF-${\kappa}B$.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.392-405
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• 2020

Purpose: Titanium implants are widely used in the treatment of dentition defects; however, due to problems such as osseointegration failure, peri-implant bone resorption, and periimplant inflammation, their application is subject to certain restrictions. The surface modification of titanium implants can improve the implant success rate and meet the needs of clinical applications. The goal of this study was to evaluate the effect of the use of porous titanium with a chitosan/hydroxyapatite coating on osseointegration. Methods: Titanium implants with a dense core and a porous outer structure were prepared using a computer-aided design model and selective laser sintering technology, with a fabricated chitosan/hydroxyapatite composite coating on their surfaces. In vivo and in vitro experiments were used to assess osteogenesis. Results: The quasi-elastic gradient and compressive strength of porous titanium implants were observed to decrease as the porosity increased. The in vitro experiments demonstrated that, the porous titanium implants had no biological toxicity; additionally, the porous structure was shown to be superior to dense titanium with regard to facilitating the adhesion and proliferation of osteoblast-like MC3T3-E1 cells. The in vivo experimental results also showed that the porous structure was beneficial, as bone tissue could grow into the pores, thereby exhibiting good osseointegration. Conclusions: Porous titanium with a chitosan/hydroxyapatite coating promoted MC3T3-E1 cell proliferation and differentiation, and also improved osseointegration in vitro. This study has meaningful implications for research into ways of improving the surface structures of implants and promoting implant osseointegration.

• Journal of Korean Neurosurgical Society
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• v.64 no.3
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• pp.386-405
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• 2021

Recent advancements in basic research on the process of secondary neurulation and increased clinical experience with caudal spinal anomalies with associated abnormalities in the surrounding and distal structures shed light on further understanding of the pathoembryogenesis of the lesions and led to the new classification of these dysraphic entities. We summarized the changing concepts of lesions developed from the disordered secondary neurulation shown during the last decade. In addition, we suggested our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase of development may cause corresponding lesions, such as failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neuro-cutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and regression failure spectrum of the medullary cord (thickened filum and filar cyst, low-lying conus, retained medullary cord, terminal myelocele and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association with the activity of caudal mesenchymal tissue in secondary neurulation involves a wider range of surrounding structures than in primary neurulation. Although the majority of the data are from animals, not from humans and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.111-117
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• 2006

An area of current research is investigating the app1ication of human mesenchymal stem cells or hMSCs as a cell-based regenerative therapy. In order to achieve effective bone regeneration, appropriate matrices functioning as cell-carriers must be identified and optimized in terms of function, efficacy and biocompatibility. Two methods of approaching optimization of matrices are to facilitate adhesion of the donor hMSCs and furthermore to facilitate recruitment of host progenitor cells to osteoblastic differentiation. Pleiotrophin is an extracellular matrix protein that was first identified in developing rat brains and believed to be associated with developing neuronal pathways. A recent publication by Imai and colleagues demonstrated that transgenic mice with upregulated pleiotrophin expression developed a greater volume of cortical as well as cancellous bone. The proposed mechanism of action of pleiotrophin is demonstrated here. Through either environmental stresses and/or intracellular regulation, there is an increase in pleiotrophin production. The pleiotrophin is released extracellularly into areas requiring bone deposition. A receptor-mediated process recruits host osteoprogenitor cells into these areas. Therefore, the aim of our study was to investigate the osteoconductive properties of pleiotrophin. We wanted to determine if pleiotrophin coating facilitates cellular adhesion and furthermore if this has any effect on hMSCs derived bone formation in an animal model. The results showed a dose dependent response of cellular adhesion in fibronectin samples, and cellular adhesion was facilitated with increasing pleiotrophin concentrations. Histologic findings taken after 5 weeks implantation in SCID mouse showed no presence of bone formation with only a dense fibrous connective tissue. Possible explanations for the results of the osteogenesis assay include inappropriate cell loading.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.143-148
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• 2005

Chemotactic migration of bone forming cell, osteoblast, is an important event during bone formation, bone remodeling, and fracture healing. Migration of cells is mediated by adhesion receptors, such as integrins, that link the cell to extracellular matrix ligands, type I collagen, fibronectin, laminin and depend on interaction between integrin and extracellular ligand. Our study was designed to investigate the effect of extracellular matrix like fibronectin, laminin, type I collagen on migration of osteoblast. Migration distance and speed of MC3T3-E1 cell on extracellular matrix-coated glass were measured for 24 hours using 0.01% type I collagen, 0.01% fibronectin, 100 microliter/ml laminin. The migration distance and speed of MC3T3-E1 cell was compared using a video-microscopy system. To determine migration speed, cells were viewed with a 4 phase- contrast lens and video recorded. Images were captured using a color CCD camera and saved in 8-bit full-color mode. The migration distance on 0.01% type I collagen or 0.01% fibronectin was longer than that on $100{\mu}l/ml$ laminin-coated glass. The migration speed on fibronectin-coated glass was 68 micrometer/hour which was fastest. The migration speed on type I collagen-coated glass was similar with that on fibronectin-coated glass. The latter two migration speeds were faster than that on no-coated glass. On the other hand, the average migration speed on laminin-coated glass was 37micrometer/hour and not different from that of control group. In conclusion, the extracelluar matrix ligands such as type I collagen and fibronectin seem to play an important role in cell migration. The type I collagen or fibronectin coated scaffold is more effective for migration of osteoblast in tissue engineering process.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.52.1-52.8
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• 2019

Background: A compact passive oxide layer can grow on tantalum (Ta). It has been reported that this oxide layer can facilitate bone ingrowth in vivo though the development of bone-like apatite, which promotes hard and soft tissue adhesion. Thus, Ta surface treatment on facial implant materials may improve the tissue response, which could result in less fibrotic encapsulation and make the implant more stable on the bone surface. The purposes of this study were to verify whether surface treatment of facial implant materials using Ta can improve the biohistobiological response and to determine the possibility of potential clinical applications. Methods: Two different and commonly used implant materials, silicone and expanded polytetrafluoroethylene (ePTFE), were treated via Ta ion implantation using a Ta sputtering gun. Ta-treated samples were compared with untreated samples using in vitro and in vivo evaluations. Osteoblast (MG-63) and fibroblast (NIH3T3) cell viability with the Ta-treated implant material was assessed, and the tissue response was observed by placing the implants over the rat calvarium (n = 48) for two different lengths of time. Foreign body and inflammatory reactions were observed, and soft tissue thickness between the calvarium and the implant as well as the bone response was measured. Results: The treatment of facial implant materials using Ta showed a tendency toward increased fibroblast and osteoblast viability, although this result was not statistically significant. During the in vivo study, both Ta-treated and untreated implants showed similar foreign body reactions. However, the Ta-treated implant materials (silicone and ePTFE) showed a tendency toward better histological features: lower soft tissue thickness between the implant and the underlying calvarium as well as an increase in new bone activity. Conclusion: Ta surface treatment using ion implantation on silicone and ePTFE facial implant materials showed the possibility of reducing soft tissue intervention between the calvarium and the implant to make the implant more stable on the bone surface. Although no statistically significant improvement was observed, Ta treatment revealed a tendency toward an improved biohistological response of silicone and ePTFE facial implants. Conclusively, tantalum treatment is beneficial and has the potential for clinical applications.

• Korean Journal of Veterinary Service
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• v.26 no.1
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• pp.67-71
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• 2003

A 8 months old, female domestic Shorthair cat with long-term signalment of anorexia, lacrimation, uveitis and coughing was submitted to the Pathology and Diagnosis Reference Division, NVRQS, Korea, for necropsy. Main gross lesions were characterized by ascities, some grayish-white nodular formation and fibrous adhesion on the surface of visceral organs including liver and kidney. Principle histopathological findings were fibrinous serositis, multifocal granuloma and necrosis, vasculitis, perivasculitis in various pharenchymal organs. Paraffin-embedded tissue sections taken from most of organs with granulomatous lesions were confirmed specific reaction to the monoclonal antibody of feline infectious peritonitis virus in the cytoplasm of many infiltrating macrophages by immunohistochemistry. The report was to describe the pathological lesions of the first naturally-occuring FIP case in companion cat of Korea.

• Journal of Chest Surgery
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• v.20 no.3
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• pp.593-597
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• 1987

Mesothelioma is a primary tumor of the pleura. There are two forms of mesotheliomas; diffuse form and localized form. The majority of localized mesotheliomas are benign, but the tumor with pedicle recur at 20% after removal of it. Malignant localized fibrous mesothelioma is differential diagnosed pathologically and clinically with diffuse mesothelioma. Symptoms of localized mesothelioma are generally related to the size of the tumor. We presented one case of malignant localized fibrous mesothelioma. The patient was 32 years old female and chief complaints were dyspnea and dry cough. Sputum cytology and needle lung biopsy were not able to diagnose definitely the tumor. Explothoracotomy was carried out for definite tissue biopsy. At the time of operation, huge adult head size mass was in the right thoracic cavity. The surface of the mass was nodular, multilobular and had hard consistency. Pedicle was formed above first rib and its diameter was 4.5cm. There was no adhesion except to RUL. Frozen biopsy suggested mesothelioma. Extirpation of the mass, right upper lobectomy. and partial pleurectomy were carried out.

• Journal of Chest Surgery
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• v.34 no.5
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• pp.437-440
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• 2001

Synovial sarcoma is a malignant soft tissue tumor that primarily occurs in the praarticular regions, especially in the knee. They are composed of keratin-positive epithelial cells and vimentin-positive spindle cells. We report a 76 year old woman with a primary synovial sarcoma in the mediastinum that had severe adhesion to the right side of pericardium. Primary synovial in the midiastinum is extremely rare and this is the first case reported in the Korean literature. The mass including the pericardium was resected and the defect was closed with Gore-Tex patch. The patient is well and free of disease 6 months after the operation.