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Search Results: 1 - 10 of 46106 matches for " Dong-Ku Kim "
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T lymphocytes derived from human cord blood provide effective antitumor immunotherapy against a human tumor
Yong-Soo Lee, Tae-Sik Kim, Dong-Ku Kim
BMC Cancer , 2011, DOI: 10.1186/1471-2407-11-225
Abstract: We established the animal model by transplantation of CB mononuclear cells and/or tumor cells into NOD/SCID mice. The presence of CB derived T cells in NOD/SCID mice or tumor tissues were determined by flow cytometric and immunohistochemical analysis. The anti-tumor effects of CB derived T cells against tumor was determined by tumor size and weight, and by the cytotoxicity assay and ELISPOT assay of T cells.We found dramatic tumor remission following transfer of CB mononuclear cells into NOD/SCID mice with human cervical tumors with a high infiltration of CD3+ T cells in tumors. NOD/SCID mice that receive neonatal CB transplants have reconstituted T cells with significant antitumor effects against human cervical and lung tumors, with a high infiltration of CD3+ T cells showing dramatic induction of apoptotic cell death. We also confirmed that T cells showed tumor specific antigen cytotoxicity in vitro. In adoptive transfer of CD3+ T cells into mice with pre-established tumors, we observed much higher antitumor effects of HPV-specific T cells by ELISPOT assays.Our results show that CB derived T lymphocytes will be useful for novel immunotherapeutic candidate cells for therapy of several tumors in clinic.Human umbilical cord blood (CB) has been used successfully as an alternative to allogeneic bone marrow for hematopoietic reconstitution in various hematological disorders. This clinical application is used because CB is readily available and has a rich source of hematopoietic stem cells with highly proliferative capacities [1-3]. There are some reports that CB is composed of phenotypically and functionally immature cytotoxic T lymphocytes (CTLs) with decreased alloantigen-specific cytotoxicity. In comparison to CTLs in peripheral blood, the CTLs derived from cord blood show a high expression of CD45RA (a na?ve T cell marker) and a low expression of CD45RO (an activated T cell marker) [4-7]. However, CB-T cells have more polyclonal diversity in complementarity of deter
Gene expression profiling of cancer stem cell in human lung adenocarcinoma A549 cells
Dong-Cheol Seo, Ji-Min Sung, Hee-Jung Cho, Hee Yi, Kun-Ho Seo, In-Soo Choi, Dong-Ku Kim, Jin-Suk Kim, Abd El-Aty AM, Ho-Chul Shin
Molecular Cancer , 2007, DOI: 10.1186/1476-4598-6-75
Abstract: We isolated CSCs from A549 cell line of which side population (SP) phenotype revealed several stem cell properties. After staining the cell line with Hoechst 33342 dye, the SP and non-side population (non-SP) cells were sorted using flow cytometric analysis. The mRNA expression profiles were measured using an Affymetrix GeneChip? oligonucleotide array. Among the sixty one differentially expressed genes, the twelve genes inclusive three poor prognostic genes; Aldo-keto reductase family 1, member C1/C2 (AKR1C1/C2), Transmembrane 4 L six family member 1 nuclear receptor (TM4SF1), and Nuclear receptor subfamily 0, group B, member 1 (NR0B1) were significantly up-regulated in SP compared to non-SP cells.This is the first report indicating the differences of gene expression pattern between SP and non-SP cells in A549 cells. We suggest that the up-regulations of the genes AKR1C1/C2, TM4SF1 and NR0B1 in SP of human adenocarcinoma A549 cells could be a target of poor prognosis in anti-cancer therapy.Cancer stem cell hypothesis is the tumoral cells which have stem cell features such as self-renewal, high migration capacity, drug resistance, and aberrant differentiation which constitute the heterogeneous population of tumor [1,2]. Tissue-specific stem cells are defined by their ability to self-renew and to produce the well differentiated and functional cells within an organ. Differentiated cells are generally short-lived; in skin and blood for example, they are produced from a small pool of long-lived stem cells that last throughout the life [3-6]. Therefore, stem cells are necessary for tissue development, replacement, and repair [7]. On the other hands, the longevity of stem cells make them susceptible to accumulating genetic damage and thereby representing the growth root for cancer recurrence following treatment [8]. It was reported that some of the tumor stem cells can survive chemotherapy and support re-growth of the tumor mass [9].Cancer stem cells (CSCs) were first iden
Alpha 1,3-Galactosyltransferase Deficiency in Pigs Increases Sialyltransferase Activities That Potentially Raise Non-Gal Xenoantigenicity
Jong-Yi Park,Mi-Ryung Park,Deug-Nam Kwon,Min-Hui Kang,Mihye Oh,Jae-Woong Han,Ssang-Goo Cho,Chankyu Park,Dong-Ku Kim,Hyuk Song,Jae-Wook Oh,Jin-Hoi Kim
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/560850
Abstract: We examined whether deficiency of the GGTA1 gene in pigs altered the expression of several glycosyltransferase genes. Real-time RT-PCR and glycosyltransferase activity showed that 2 sialyltransferases [α2,3-sialyltransferase (α2,3ST) and α2,6-sialyltransferase (α2,6ST)] in the heterozygote GalT KO liver have higher expression levels and activities compared to controls. Enzyme-linked lectin assays indicated that there were also more sialic acid-containing glycoconjugate epitopes in GalT KO livers than in controls. The elevated level of sialic-acid-containing glycoconjugate epitopes was due to the low level of α-Gal in heterozygote GalT KO livers. Furthermore, proteomics analysis showed that heterozygote GalT KO pigs had a higher expression of NAD
From Blood to the Brain: Can Systemically Transplanted Mesenchymal Stem Cells Cross the Blood-Brain Barrier?
Linan Liu,Mark A. Eckert,Hamidreza Riazifar,Dong-Ku Kang,Dritan Agalliu,Weian Zhao
Stem Cells International , 2013, DOI: 10.1155/2013/435093
Abstract: Systemically infused mesenchymal stem cells (MSCs) are emerging therapeutics for treating stroke, acute injuries, and inflammatory diseases of the central nervous system (CNS), as well as brain tumors due to their regenerative capacity and ability to secrete trophic, immune modulatory, or other engineered therapeutic factors. It is hypothesized that transplanted MSCs home to and engraft at ischemic and injured sites in the brain in order to exert their therapeutic effects. However, whether MSCs possess the ability to migrate across the blood-brain barrier (BBB) that separates the blood from the brain remains unresolved. This review analyzes recent advances in this area in an attempt to elucidate whether systemically infused MSCs are able to actively transmigrate across the CNS endothelium, particularly under conditions of injury or stroke. Understanding the fate of transplanted MSCs and their CNS trafficking mechanisms will facilitate the development of more effective stem-cell-based therapeutics and drug delivery systems to treat neurological diseases and brain tumors. 1. Introduction Despite enormous advances in our understanding of the molecular and cellular basis of neurological diseases, therapies that lead to sustained improvement or resolution of symptoms have remained elusive. Regenerative therapeutics, that encompass embryonic, neural, and adult stem cell therapies, possess great potential to reverse neuronal damage associated with CNS diseases such as stroke, multiple sclerosis (MS), Parkinson’s disease (PD), and Alzheimer’s disease (AD) [1]. Mesenchymal stem cells (MSCs) are an especially attractive therapeutic agent due to their ease of isolation, established safety, and potential to target multiple pathways involved in neuronal regeneration. MSCs are connective tissue progenitors that can be readily isolated from multiple tissues including bone marrow and adipose tissue [2–4]. While being initially used for treatment of connective tissue disorders due to their potential to differentiate into bone, cartilage, and fat cells, the discovery that MSCs can secrete cytokines and growth factors with antiapoptotic, proangiogenic, neuroprotective, and immune-modulatory properties has sparked broad clinical interest [2–4]. In fact, MSCs are the world’s first manufactured stem cell product (i.e., Osiris’s Prochymal) approved in Canada to treat graft-versus-host disease (GvHD) [5]. MSCs are currently being tested for treating some neurological diseases in multiple ongoing clinical trials, although their exact therapeutic mechanisms in vivo remain
Linear Degrees of Freedom of MIMO Broadcast Channels with Reconfigurable Antennas in the Absence of CSIT
Minho Yang,Sang-Woon Jeon,Dong Ku Kim
Mathematics , 2014,
Abstract: The K-user multiple-input and multiple-output (MIMO) broadcast channel (BC) with no channel state information at the transmitter (CSIT) is considered, where each receiver is assumed to be equipped with reconfigurable antennas capable of choosing a subset of receiving modes from several preset modes. Under general antenna configurations, the sum linear degrees of freedom (LDoF) of the K-user MIMO BC with reconfigurable antennas is completely characterized, which corresponds to the maximum sum DoF achievable by linear coding strategies. The LDoF region is further characterized for a class of antenna configurations. Similar analysis is extended to the K-user MIMO interference channels with reconfigurable antennas and the sum LDoF is characterized for a class of antenna configurations.
An Approximation of the Outage Probability for Multi-hop AF Fixed Gain Relay
Jun Kyoung Lee,Janghoon Yang,Dong Ku Kim
Computer Science , 2008,
Abstract: In this letter, we present a closed-form approximation of the outage probability for the multi-hop amplify-and-forward (AF) relaying systems with fixed gain in Rayleigh fading channel. The approximation is derived from the outage event for each hop. The simulation results show the tightness of the proposed approximation in low and high signal-to-noise ratio (SNR) region.
The Feasibility of Interference Alignment for Reverse TDD Systems in MIMO Cellular Networks
Kiyeon Kim,Sang-Woon Jeon,Janghoon Yang,Dong Ku Kim
Mathematics , 2014,
Abstract: The feasibility conditions of interference alignment (IA) are analyzed for reverse TDD systems, i.e., one cell operates as downlink (DL) but the other cell operates as uplink (UL). Under general multiple-input and multiple-output (MIMO) antenna configurations, a necessary condition and a sufficient condition for one-shot linear IA are established, i.e., linear IA without symbol or time extension. In several example networks, optimal sum degrees of freedom (DoF) is characterized by the derived necessary condition and sufficient condition. For symmetric DoF within each cell, a sufficient condition is established in a more compact expression, which yields the necessary and sufficient condition for a class of symmetric DoF. An iterative construction of transmit and received beamforming vectors is further proposed, which provides a specific beamforming design satisfying one-shot IA. Simulation results demonstrate that the proposed IA not only achieve lager DoF but also significantly improve the sum rate in the practical signal-to-noise ratio (SNR) regime.
Prototyping Real-Time Full Duplex Radios
MinKeun Chung,Min Soo Sim,Jaeweon Kim,Dong Ku Kim,Chan-Byoung Chae
Computer Science , 2015,
Abstract: In this article, we present a real-time full duplex radio system for 5G wireless networks. Full duplex radios are capable of opening new possibilities in contexts of high traffic demand where there are limited radio resources. A critical issue, however, to implementing full duplex radios, in real wireless environments, is being able to cancel self-interference. To overcome the self-interference challenge, we prototype our design on a software-defined radio (SDR) platform. This design combines a dual-polarization antenna-based analog part with a digital self-interference canceller that operates in real-time. Prototype test results confirm that the proposed full-duplex system achieves about 1.9 times higher throughput than a half-duplex system. This article concludes with a discussion of implementationchallenges that remain for researchers seeking the most viable solution for full duplex communications.
6 MV photon beam modeling for Varian Clinac iX using GEANT4 virtual jaw
Byung Yong Kim,Hyung Dong Kim,Dong Ho Kim,Jong Geun Baek,Su Ho Moon,Gwang Won Rho,Jeong Ku Kang,Sung Kyu Kim
Physics , 2015,
Abstract: Most virtual source models (VSM) use beam modeling, with the exception of the patient-dependent secondary collimator (jaw). Unlike other components of the treatment head, the jaw absorbs many photons generated by the bremsstrahlung, which decreases the efficiency of the simulation. In the present study, a new method of beam modeling using a virtual jaw was applied to improve the calculation efficiency of VSM. The results for the percentage depth dose and profile of the virtual jaw VSM calculated in a homogeneous water phantom agreed with the measurement results for the CC13 cylinder type ion chamber within an error rate of 2%, and the 80 to 20% penumbra width agreed with the measurement results within an error of 0.6 mm. Compared with the existing VSM, in which a great number of photons are absorbed, the calculation efficiency of the VSM using the virtual jaw was expected to increase by approximately 67%.
Lessons Learned from Practical Independent Verification and Validation Based on IEEE 1012  [PDF]
Joon Ku Lee, Yang Mo Kim
Journal of Software Engineering and Applications (JSEA) , 2012, DOI: 10.4236/jsea.2012.510093
Abstract: IEEE 1012 [1] describes the SDLC phase activities for software independent verification and validation (IV & V) for nuclear power plant in truly general and conceptual manner, which requires the upward and/or downward tailoring on its interpretation for practical IV & V. It contains crucial and encompassing check points and guidelines to analyze the design integrity, without addressing the formalized and the specific criteria for IV & V activities confirming the technical integrity. It is necessary to list up the inspection viewpoint via interpretation of the standard that is practical review points checking design consistency. For fruitful IV & V of Control Element Driving Mechanism Control System (CEDMCS) software for Yonggwang Nuclear Power Plant unit 3 & 4, the specific viewpoints and approach are necessary based on the guidelines of IEEE 1012 to enhance the system quality by considering the level of implementation of the theoretical and the practical IV & V. Additionally IV & V guideline of IEEE 1012 does not specifically provide the concrete measure considering the system characteristics of CEDMCS. This paper provides the seven (7) characteristic criteria for CEDMCS IV & V, and by applying these viewpoints, the design analysis such as function, performance, interface and exception, backward and forward requirement traceability analysis has been conducted. The requirement, design, implementation, and test phase were only considered for IV & V in this project. This article also provides the translation of code to map theoretical verification and validation into practical verification and validation. This paper emphasizes the necessity of the intensive design inspection and walkthrough for requirement phase to resolve the design faults because the IV & V of early phase of SDLC obviously contributes to find out most of critical design inconsistency. Especially for test phase IV & V, it is strongly recommended to prepare the test plan document which is going to be the basis for the test coverage selection and test strategy. This test plan document should be based on the critical characteristics of function and performance of CEDMCS. Also to guarantee the independency of V & V organization participating in this project, and to acquire the full package of design details for IV & V, the systematic approach and efforts with an aspect of management is highlighted among the participants.
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