• Journal of Chest Surgery
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• v.29 no.10
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• pp.1111-1117
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• 1996

Structural deterioration of the bioprosthetic xenograft valves due to primary tissue failure occurs in two modes: from fatigue lesions with tear and wear with or without calcification and from calcification with obstruction. Two groups of consecutive 56 patients with the Hancock porcine ortic valve(HM) and of 1 13 patients with the standard-profile onescu-Shiley bovine pericardial valve(ISM) explanted from mitral position at the time of re-replacement surgery for primary tissue failure at Seoul national University Hospital until 1994, were studied for clinical and pathological features. Their ages at primary implant were 31.9 $\pm$9.2 years In HM and 30.4$\pm$ 12.5 years in ISM. Hemodrnamic dysfunction of the failed mitral bloprostheses were predominantly insufficiency in HM(64.3%) and stenosis in ISM(51.3%)(p<0.001). Pathologic findings of the explanted mitral valves reflected these hemodynamic changes, revealing failure more often from tissue damage(tears and wears) in HM and more often from calcification in ISM(p< 0.001). Explant period(from primary implant to explant) was relatively short in ISM(8.7$\pm$2.6years), compared with the one in HM(10.4 $\pm$2.6 years)(p<0.001). In conclusion, both the Hancock and the lonescu-shiley valves would fail from calcification as well as issue damage. However, while the Hancock porcine valves in mitral position failed more frequently from tissue failure and insufficiency, the standard-profile lonescu-Shiley pericardial valves did from calcification and stenosis, especially in young pAtients . Although the possibility of less occurrence of valve failure from mechanical reasons may be expected with newer generation bloprostheses, it does not seem to Improve durability significantly unless further refinement in antimineralization is achieved. Therefore, clinical use of the glutaraldehyde-treated bioprosthetic valves is, at present, limited to the patients of advanced age groups.

• BMB Reports
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• v.53 no.10
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• pp.533-538
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• 2020

Notch signaling has been identified as a critical pathway in gastric cancer (GC) progression and metastasis, and inhibition of Delta-like ligand 4 (DLL4), a Notch ligand, is suggested as a potent therapeutic approach for GC. Expression of both DLL4 and vascular endothelial growth factor receptor 2 (VEGFR2) was similar in the malignant tissues of GC patients. We focused on vascular endothelial growth factor (VEGF), a known angiogenesis regulator and activator of DLL4. Here, we used ABL001, a DLL4/VEGF bispecific therapeutic antibody, and investigated its therapeutic effect in GC. Treatment with human DLL4 therapeutic antibody (anti-hDLL4) or ABL001 slightly reduced GC cell growth in monolayer culture; however, they significantly inhibited cell growth in 3D-culture, suggesting a reduction in the cancer stem cell population. Treatment with anti-hDLL4 or ABL001 also decreased GC cell migration and invasion. Moreover, the combined treatment of irinotecan with anti-hDLL4 or ABL001 showed synergistic antitumor activity. Both combination treatments further reduced cell growth in 3D-culture as well as cell invasion. Interestingly, the combination treatment of ABL001 with irinotecan synergistically reduced the GC burden in both xenograft and orthotopic mouse models. Collectively, DLL4 inhibition significantly decreased cell motility and stem-like phenotype and the combination treatment of DLL4/VEGF bispecific therapeutic antibody with irinotecan synergistically reduced the GC burden in mouse models. Our data suggest that ABL001 potentially represents a potent agent in GC therapy. Further biochemical and pre-clinical studies are needed for its application in the clinic.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7363-7369
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• 2014

The present study aimed to prepare and evaluate polymeric micelles conjugated with folic acid through ${\alpha}$- or ${\gamma}$-carboxyl groups for antitumor efficacy. The isomeric block copolymers, ${\alpha}$- and ${\gamma}$-folate-polyethyleneglycol-distearoyl phosphatidylethanolamine (${\alpha}$- and ${\gamma}$-Fol-PEG-DSPE), were produced by solid phase peptide synthesis. Three types of doxorubicin (DOX)-loaded polymeric micelles (MPEG-DSPE-DOX and ${\alpha}$- / ${\gamma}$-Fol-PEG-DSPEDOX micelles) were prepared via the film formation method. Compared with MPEG-DSPE-DOX micelles, the ${\alpha}$- / ${\gamma}$-Fol-PEG-DSPE-DOX micelles presented a higher cellular uptake behavior in the live cell study. Cell viability percentages were 81.8%, 57.3%, 56.6% at 2 hours for MPEG-DSPE-DOX, ${\alpha}$- and ${\gamma}$-Fol-PEG-DSPE-DOX micelles, respectively (p<0.05). Using the KB xenograft tumor model, both ${\alpha}$- and ${\gamma}$-folate-conjugated micelles were found to have better antitumor effects with lower toxicity in comparison with MPEG-DSPE-DOX micelles. No difference in in vivo antitumor efficacy was found between ${\alpha}$- and ${\gamma}$-Fol-PEG-DSPE-DOX micelles. The folate-conjugated micelles might be a potentially useful strategy for tumor targeting of therapeutic agents, whether grafting with folic acid through ${\alpha}$- or ${\gamma}$-carboxyl groups.

• Journal of Gastric Cancer
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• v.20 no.1
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• pp.60-71
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• 2020

Purpose: The utility of 18-fluordesoxyglucose positron emission tomography ([¹⁸F]-FDG-PET) combined with computer tomography or magnetic resonance imaging (MRI) in gastric cancer remains controversial and a rationale for patient selection is desired. This study aims to establish a preclinical patient-derived xenograft (PDX) based [¹⁸F]-FDG-PET/MRI protocol for gastric cancer and compare different PDX models regarding tumor growth and FDG uptake. Materials and Methods: Female BALB/c nu/nu mice were implanted orthotopically and subcutaneously with gastric cancer PDX. [¹⁸F]-FDG-PET/MRI scanning protocol evaluation included different tumor sizes, FDG doses, scanning intervals, and organ-specific uptake. FDG avidity of similar PDX cases were compared between ortho- and heterotopic tumor implantation methods. Microscopic and immunohistochemical investigations were performed to confirm tumor growth and correlate the glycolysis markers glucose transporter 1 (GLUT1) and hexokinase 2 (HK2) with FDG uptake. Results: Organ-specific uptake analysis showed specific FDG avidity of the tumor tissue. Standard scanning protocol was determined to include 150 μCi FDG injection dose and scanning after one hour. Comparison of heterotopic and orthotopic implanted mice revealed a long growth interval for orthotopic models with a high uptake in similar PDX tissues. The H-score of GLUT1 and HK2 expression in tumor cells correlated with the measured maximal standardized uptake value values (GLUT1: Pearson r=0.743, P=0.009; HK2: Pearson r=0.605, P=0.049). Conclusions: This preclinical gastric cancer PDX based [¹⁸F]-FDG-PET/MRI protocol reveals tumor specific FDG uptake and shows correlation to glucose metabolic proteins. Our findings provide a PET/MRI PDX model that can be applicable for translational gastric cancer research.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.199-210
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• 1993

Many surgeons are on the point of bone excision and reconstruction of the bone defects by autograft. xenograft, and allograft in the treatment of begin and malignant tumors of bone. Of all type of bone grafts, we received the autograft as the best ideal bone graft. Of autogenic bone graft, replantation of excised autogenic bone for reconstructiong the bone defects has been the ideal method until now, but early bone healing reponses and tumor cell devitalization after replantation of excised autogenic bone have not been identified for clinical applications. So, to evaluate bone healing response after replantation in rabbit's calvarial bone, we divided the experimental group into three groups. Group 1 is a fresh autogenous bone group. Group 2 is a deep frozen group. Group 3 is freeze-dried demineralized group. Obtained result were as followed: 1. Inflammatory cell infiltration appeared at I week and disappeared at 4 weeks in all experimental group, Especially, severe inflammatory cell infiltration showed in fresh autogenous bone group at 2 weeks. Group 3 is the least showing group on the point of inflammatory cell infiltration. 2. Osteoblastic activity evenly increased upto 4 weeks and maintained to 6 weeks and decreased after this period, especially osteoblastic activity in group 2 is less than group 1 and group 3. We can't discriminate between osteoblastic activity of group 1 and that of group 3. 3. In new bone formation, group 3 was more active than any other groups at early stage, but there were little differences among three experimental groups at later state. 4. Bone resorption around the grafted bone slightly appeared at 1 week and disappeared at 4 weeks in all experimental groups. We can find the more bone resorption in group 2 at 2 weeks than any other groups. We could suggest, as appears from our results, that freeze-dried deminiralized bone graft is the useful bone graft in the clinical applications of excised autogenic bone.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.74-82
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• 2009

In order to make successful oral cancer treatment, we need to understand about tumor biology and effective chemotherapeutic agents. To achieve these studies, it is necessary to develope a proper in-vivo model. Therefore the author will make try to develop more improved animal model of more applicable in various method of cancer study. In this study, the author induced in-vivo tumorigenesis in nude mice by $YD-10B_{mod}$ cell line used by YD-10B cell line originated from oral tongue squamous cell carcinoma and observed tumor formations and invasiveness of surrounding tissue, and found some results as follows : 1. The experimental group($YD-10B_{mod}$, subcutaneous injection) produced tumors 13 out of 15 mice, while the control group produced none of 5 mice. 2. The inoculation of $1{\times}10^6$cells/mouse produced tumors 3 out of 5 mice and inoculation of $1{\times}10^7$cells/mouse, $2{\times}10^7$cells/mouse produced tumors in every 5 mice. 3. In the histopathologic studies, the inoculation of $1{\times}10^6$cells/mouse group showed the characteristic features of well-differentiated squamous cell carcinoma and demarcated expansile growth, while the inoculation of $1{\times}10^7$cells/mouse, $2{\times}10^7$cells/mouse group showed the expansile growth with partial central necrosis and invasive growth to surrounding fat & connective tissue. These findings suggest that atopic xenograft of $YD-10B_{mod}$ cell line in nude mice has a improved productivity of tumors, produced tumors showed the characteristics feature of human tumor and invasive growth to surrounding tissue in histopathologic appearance. These atopic nude mouse model of tongue carcinoma might assist in studying oral cancer biology and effective choice of chemotherapeutic agents.

• Reproductive and Developmental Biology
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• v.32 no.1
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• pp.1-7
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• 2008

The SCID-repopulation cells(SRCs) assay has been widely used to determine the self-renewal capacity of hematopoietic stem cells (HSCs). In this study, we tested the repopulating efficiency of porcine bone marrow derived hematopoietic stem cells using nonobese diabetic/severe combined immunodieficient (NOD/SCID) mice which was inherited immunodeficiency mire with defect of T cells, B cells, and low activity of NK cells. We transplanted porcine bone marrow hematopoietic stem/progenitor cells with intraperitoneal injection into neonate NOD/SCID mice. We confirmed efficient reconstitution activity of inoculated porcine hematopoietis cells in variety of organs of NOD/SCID mice. Interestingly, pig $CD3^+$ T lymphocytes detected with high level in liver($15.6{\pm}3.7%$), spleen($5.6{\pm}3.0%$), thymus($1.5{\pm}1.3%$), and BM($2.3{\pm}0.9%$), respectively. These data imply that microenvironment of neonate NOD/SCID mice is very efficient for proliferation and differentiation of porcine T cells, and can be useful for the study of T cells development and renogeneic organ transplantation.

• Korean Journal of Head & Neck Oncology
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• v.30 no.2
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• pp.53-61
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• 2014

Background and Objectives : Anaplastic thyroid carcinoma(ATC) is a rare but highly aggressive thyroid malignancy that is associated with an extremely poor survival despite the best multidisciplinary care. BRAF(V600E) mutation is detected in about a quarter of ATC, but unlike its high treatment response to selective BRAF inhibitor (PLX4032) in metastatic melanoma, the treatment response of ATC is reported to be low. The purpose of this study is to investigate the innate resistance mechanism responsible for this low treatment response to BRAF inhibitor and its effect on epithelial-mesenchymal transition(EMT). Materials and Methods : Two ATP cell lines, 8505C and FRO were selected and treated with PLX4032 and its drug sensitivity and effects on cell migration and EMT were examined and compared. Further investigation on the changes in signals responsible for the different treatment response to PLX4032 was carried out and the same experiment was performed on both orthotopic and ectopic xenograft mouse models. Results : FRO cell line was more sensitive to PLX4032 treatment compared to 8505C cell line. The resistance to BRAF inhibition in 8505C was due to increased expression of EGFR. Effective inhibition of both EGFR and p-AKT was achieved after dual treatment with BRAF inhibitor(PLX4032) and EGFR inhibitor(Erlotinib). Similar results were confirmed on in vivo study. Conclusion : EGFR-mediated reactivation of the PI3K/AKT pathway and MAPK pathway contributes to the relative insensitivity of BRAF(V600E) mutant ATC cells to PLX4032. Dual inhibition of BRAF and EGFR leads to sustained treatment response including cell invasiveness.

• Korean Journal of Head & Neck Oncology
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• v.35 no.2
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• pp.19-25
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• 2019

Background/Objectives: Although anaplastic thyroid carcinoma (ATC) is rare, it is one of the deadliest forms of thyroid cancer. The fatality rate for ATC is high, and the survival rate at one year after diagnosis is <20%. The present study aimed to investigate the anti-tumor activities of paclitaxel, radiation, and tyrosine kinase inhibitor (TKI) combined therapy in anaplastic thyroid cancer cells both in vitro and in vivo and explore its effects on apoptotic cell death pathways. Materials & Methods: ATC cell line was exposed to TKI, lenvatinib in the presence or absence of paclitaxel with radiation, and cell viability was determined by MTT assay. Effects of the combined treatment on cell cycle and intracellular signaling pathways were assessed by flow cytometry and western blot analysis. The ATC cell line xenograft model was used to examine the anti-tumor activity in vivo. Results: Our data revealed that the combined administration of paclitaxel, TKI, and radiation decreased cell viability in ATC cells, and also significantly increased apoptotic cell death in these cells, as demonstrated by the cleavage of caspase-3 and DNA fragmentation. This combination therapy reduced anti-apoptotic factor levels in ATC cells, while significantly decreasing tumor volume and increasing survival in ATC xenografts. Conclusion: These results indicate that administering the combination of paclitaxel, TKI, and radiation therapy may exert significant anticancer effects in preclinical models, potentially suggesting a new clinical approach for treating patients with ATC.

• Polymer(Korea)
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• v.28 no.6
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• pp.478-486
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• 2004

Small intestinal submucosa (SIS) is consisted with collagen and glycosaminoglycan as well as some growth factors which can stimulate cell activity. Recently, it has been recognized that SIS has been successfully examined in the bio-medical application as biomaterials without xenograft immune-rejection response. We prepared native SIS sheets and acid treated SIS sheets by acetic acid with 1 or 5-layered sheets, respectively. The water uptake ability of native and acid treated SIS sheets was examined to evaluate the possibility as wound dressings. Morphologies of SIS sheets were characterized by SEM and the effects of various buffer solutions and different pH solutions on the water uptake ability were observed for 16 days. We observed that the acid treated SIS sheets had higher water uptake ability than native SIS sheets. Also, the water uptake ability of these was slightly higher in various buffers than distilled water. In conclusion, this study suggests that native and acid treated SIS sheets could be useful for the applications of wound dressing and biodegradable injectable materials.