• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.3
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• pp.163-181
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• 2017

In the field of orofacial surgery, a red blood cell transfusion (RBCT) is occasionally required during double jaw and oral cancer surgery. However, the question remains whether the effect of RBCT during the perioperative period is beneficial or harmful. The answer to this question remains challenging. In the field of orofacial surgery, transfusion is performed for the purpose of oxygen transfer to hypoxic tissues and plasma volume expansion when there is bleeding. However, there are various risks, such as infectious complications (viral and bacterial), transfusion-related acute lung injury, ABO and non-ABO associated hemolytic transfusion reactions, febrile non-hemolytic transfusion reactions, transfusion associated graft-versus-host disease, transfusion associated circulatory overload, and hypersensitivity transfusion reaction including anaphylaxis and transfusion-related immune-modulation. Many studies and guidelines have suggested RBCT is considered when hemoglobin levels recorded are 7 g/dL for general patients and 8-9 g/dL for patients with cardiovascular disease or hemodynamically unstable patients. However, RBCT is occasionally an essential treatment during surgeries and it is often required in emergency cases. We need to comprehensively consider postoperative bleeding, different clinical situations, the level of intra- and postoperative patient monitoring, and various problems that may arise from a transfusion, in the perspective of patient safety. Since orofacial surgery has an especially high risk of bleeding due to the complex structures involved and the extensive vascular distribution, measures to prevent bleeding should be taken and the conditions for a transfusion should be optimized and appropriate in order to promote patient safety.

• Polymer(Korea)
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• v.26 no.4
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• pp.415-421
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• 2002

A sulfonated PP-g-styrene ion-exchange hollow fiber membrane was prepared by pre-irradiation method with E-beam followed by sulfonation reaction. Degree of grafting increased with the increase of styrene monomer concentration and showed the maximum value of 128% at 80% of styrene monomer composition. Sulfonation yield increased with the degree of grafting. At 100% degree of grafting, sulfonation yield showed the maximum value of 13.4%. Ion exchange capacity of sulfonated HPP-g-styrene of 3.42 meq/g was attained, resulting in the remarkable increase of adsorption ability BET analysis proved that the surface area of sulfonated HPP-g-styrene was 62.54 $m^2/g$ and the mean pore size was 25 $\AA$. From the BSA adsorption experiments, the adsorption amount of BSA was increased with sulfonation. At 13.4% sulfonation yield the adsorption amount of BSA was maximum as 3.8 mg/g. Sulfonated HPP-g-styrene was synthesized successfully and suitable for the adsorption and separation of BSA.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.99-101
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• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

• Clinical and Experimental Pediatrics
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• v.62 no.11
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• pp.422-427
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• 2019

Background: Polyomavirus BK (BKV) infection is an important cause of graft loss in kidney transplant patients. Purpose: The purpose of this study was to evaluate clinical findings and risk factors for BKV in pediatric patients after kidney transplantation. Methods: This retrospective single-center study included 31 pediatric kidney transplant recipients from January 2002 to December 2017. Two patients received 2 transplantations during the study period, and each transplant was analyzed independently. Total number of cases is 33 cases with 31 patients. BKV infection was confirmed from blood samples via periodic quantitative polymerase chain reaction. Results: The mean age at kidney transplantation was 11.0±4.7 years, and the male-to-female ratio was 2.7:1. Three patients had a past medical history of high-dose chemotherapy and autologous stem-cell transplantation for solid tumors. Nine patients (27.3%) developed BKV infection. The median period from kidney transplantation to BKV detection in blood was 5.6 months. There was no statistically significant difference in estimated glomerular filtration rate between patients with and those without BKV infection. Among 9 patients with BKV viremia, 7 were treated by reducing their immunosuppressant dose, and BKV was cleared in 6 of these 7 patients. In the other 2 BKV-positive patients, viremia improved without immunosuppressant reduction. Conclusion: BKV infection is common in children with kidney transplantation and might not have affected short-term renal function in our patient sample due to early immunosuppressant reduction at the time of BKV detection.

• Archives of Craniofacial Surgery
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• v.18 no.3
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• pp.155-161
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• 2017

Background: Because of the relatively similar size of organs to human and the physiological and structural similarities, the use of porcine as xenograft donors is progressing very actively. In this study, we analyzed the characteristics of porcine ear cartilage and evaluated its suitability as graft material in reconstructive and cosmetic surgery. Methods: The auricular cartilage was harvested from two pigs, and subjected to histological examination by immunohistochemical staining. To determine the collagen content, samples were treated with collagenase and weight changes were measured. After sterilization by irradiation, the samples were grafted into rats and stained with Hematoxylin and Eosin and Masson Trichrome to observe inflammation and xenograft rejection. Results: In IHC staining, extracellular matrices were mainly stained with type II collagen (20.69%), keratin sulfate (10.20%), chondroitin sulfate (2.62%), and hyaluronic acid (0.84%). After collagenase treatment, the weight decreased by 68.3%, indicating that about 70% of the porcine ear cartilage was composed of collagen. Upon xenograft of the sterilized cartilages in rats, inflammatory cells were observed for up to 2 months. However, they gradually decreased, and inflammation and reject-response were rarely observed at 5 months. Conclusion: The porcine ear cartilage was covered with perichondrium and cellular constituents were found to be composed of chondrocytes and chondroblasts. In addition, the extracellular matrices were mainly composed of collagen. Upon xenograft of irradiated cartilage into rats, there was no specific inflammatory reaction around the transplanted cartilage. These findings suggest that porcine ear cartilage could be a useful alternative implant material for human cosmetic surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.5
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• pp.445-453
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• 2006

Cyclosporine A (CsA) is a powerful immunosuppresive agent used to prevent graft rejection of organ and treat autoimmune disease. One of the major side effects associated with CsA treatment is the development of gingival overgrowth. The purpose of this study was to investigate the mRNA expression and association of the several growth factors in gingival overgrowth induced by CsA, respectively. Gingival fibroblasts were obtained from gingival tissues of healthy donor and the patients treated with CsA. The cultured gingival fibroblasts were incubated with increasing concentrations of CsA for 24 hours, and the expression of MMP-1, TIMP-1, $TGF-{\beta}_1$, p21 were determined by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of MMP-1 was slightly increased according to the concentration of treated CsA, but there was no statistical significance. TIMP-1 showed the increased expression at the CsA concentration of 250 and 500 ng/ml and significantly decreased at the CsA concentration of 750ng/ml. $TGF-{\beta}_1$ showed the increased expression at the CsA concentration of 500 and 750 ng/ml. The expression of p21 was not changed significantly. We concluded that the gingival hyperplasia induced by CsA was more related with $TGF-{\beta}_1$ than MMP-1 or TIMP-1 on gingival collagen metabolism in patients treated with CsA.

• Elastomers and Composites
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• v.49 no.4
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• pp.267-274
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• 2014

Self vulcanizable blend system for magnetorheological elastomer (MRE) has been studied by dispersing magneto responsible particle (MRP) on elastomeric matrix. Chloroprene rubber was modified with maleic anhydride (MAH) using heat and pressure which is called dynamic maleation process. The optimum graft ratio of MAH was found at 10 phr contents and reaction temperature of $100^{\circ}C$. This could be confirmed by FT-IR analysis. Epoxided natural rubber (ENR) was blended with modified CR-g-MAH for self vulcanization. The optimum amounts of ENR was 30 wt% in terms of scorch time and curing rate. MRE was manufactured by electromagnetic equipment and orientation of MRE was confirmed by SEM. Finally, it was found that the tensile strength of anisotropic-MRE was higher than that of isotropic-MRE and the hardness was reverse.

• Polymer(Korea)
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• v.37 no.6
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• pp.770-776
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• 2013

The ENR 50 having the lowest gas permeability was blended with Nylon 6 which exhibits superior gas permeability, excellent wear resistance by using a twin-screw extruder. The blended materials showed the increased gas barrier property and physical properties, but did not yield a great synergistic effect due to low dispersion of Nylon 6 to ENR 50. To improve dispersion of Nylon 6 in the rubber matrix, maleic anhydride (MAH) was grafted to ENR 50. The grafting reaction between MAH and ENR 50 was evidenced using IR spectroscopy. The grafted and blended materials, ENR 50- g-MAH/Nylon 6 compounds, resulted in an enhanced gas barrier property and physical properties compared with compounds without MAH. The compound at 5 phr of MAH showed the highest crosslinking density and the best performances.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.155-160
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• 2010

In this study, we investigated primary biocompatibility and osteogenic gene expression of porous granular BCP bone substitutes with or without strontium (Sr) doping. In vitro biocompatibility was investigated on fibroblasts like L929 cells and osteoblasts like MG-63 cells using a cell viability assay (MTT) and one cell morphological observation by SEM, respectively. MTT results showed a cell viability percent of L929 fibroblasts, which was higher in Sr-BCP granules (98-101%) than in the non-doped granules (92-96%, p < 0.05). Osteoblasts like MG-63 cells were also found to proliferate better on Sr-doped BCP granules (01-111%) than on the non-doped ones (92-99%, p < 0.05) using an MTT assay. As compared with pure BCP granules, SEM images of MG-63 cells grown on sample surfaces confirmed that cellular spreading, adhesion and proliferation were facilitated by Sr doping on BCP. Active filopodial growth of MG-63 cells was also observed on Sr-doped BCP granules. The cells on Sr-doped BCP granules were well attached and spread out. Gene expression of osteonectin, osteopontin and osteoprotegrin were also evaluated using reverse transcriptase polymerase chain reaction (RT-PCR), which showed that the mRNA phenotypes of these genes were well maintained and expressed in Sr-doped BCP granules. These results suggest that Sr doping in a porous BCP granule can potentially enhance the biocompatibility and bone ingrowth capability of BCP biomaterials.

• Journal of Oral Medicine and Pain
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• v.25 no.2
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• pp.159-165
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• 2000

Subsequent to an allogenic stem cell transplantation(ASCT) on patients with hematologic malignancy(AML, ALL, CML, multiple myeloma, lymphoma etc.), chronic GVHD(graft versus host disease), which is an immunological reaction, occurs. With treatment results from patients who were diagnosed with ALL(acute lymphocytic leukemia), undergone BMT(bone marrow transplantation) and showed oral and skin lesions due to GVHD, treatment of oral manifestations of leukemia and its general management were studied. 90% of patients with chronic GVHD show change in the oral mucosa causing oral manifestations such as leukoplakia, lichenoid change of the oral mucosa, mucosal atrophy, erythema, ulceration and xerostomia. In treating GVHD, extensive systemic immunosuppression cause bacterial, viral, fungal infection that are fatal, and even if the treatment is successful, the patient is already in a severe immunosuppressed state. Therefore, localized target therapy is preferred. In another words, topical application(rinse, cream, ointment etc.) of cyclosporin and steroid in treating oral chronic GVHD is highly recommended, and the use of PUVA(Psoralen Ultraviolet A) and thalidomide is reported to be effective. In treating such diseases, dental treatment to control pain and prevent secondary infection of oral manifestations is very important. To those patients with systemic diseases who show limited effect by general dental treatment, non-invasive treatment such as the dental laser, in addition to the use of drugs, may be necessary to actively treat pain and help the healing process. For greater results, new effective methods are to be developed for treatment.