Targeting Orthotopic Glioma in Mice with Genetically Engineered Salmonella typhimurium

Wen, Min,Jung, Shin,Moon, Kyung-Sub,Jiang, Shen Nan,Li, Song-Yuan,Min, Jung-Joon The Korean Neurosurgical Society 2014 Journal of Korean neurosurgical society Vol.55 No.3

Objective : With the growing interests of bacteria as a targeting vector for cancer treatment, diverse genetically engineered Salmonella has been reported to be capable of targeting primary or metastatic tumor regions after intravenous injection into mouse tumor models. The purpose of this study was to investigate the capability of the genetically engineered Salmonella typhimurium (S. typhimurium) to access the glioma xenograft, which was monitored in mouse brain tumor models using optical bioluminescence imaging technique. Methods : U87 malignant glioma cells (U87-MG) stably transfected with firefly luciferase (Fluc) were implanted into BALB/cAnN nude mice by stereotactic injection into the striatum. After tumor formation, attenuated S. typhimurium expressing bacterial luciferase (Lux) was injected into the tail vein. Bioluminescence signals from transfected cells or bacteria were monitored using a cooled charge-coupled device camera to identify the tumor location or to trace the bacterial migration. Immunofluorescence staining was also performed in frozen sections of mouse glioma xenograft. Results : The injected S. typhimurium exclusively localized in the glioma xenograft region of U87-MG-bearing mouse. Immunofluorescence staining also demonstrated the accumulation of S. typhimurium in the brain tumors. Conclusion : The present study demonstrated that S. typhimurium can target glioma xenograft, and may provide a potentially therapeutic probe for glioma.

Genetically-engineered <i>Salmonella typhimurium</i> expressing TIMP-2 as a therapeutic intervention in an orthotopic glioma mouse model

Wen, Min,Zheng, Jin Hai,Choi, Jin Myung,Pei, Jian,Li, Chun-Hao,Li, Song-Yuan,Kim, In-Young,Lim, Sa-Hoe,Jung, Tae-Young,Moon, Kyung-Sub,Min, Jung-Joon,Jung, Shin Elsevier 2018 Cancer letters Vol.433 No.-

<P><B>Abstract</B></P> <P>Glioma is one of the most devastating and refractory cancers. The main factors underlying therapeutic failure include extremely invasive characteristics and lack of effective methods for drug delivery. Attenuated <I>Salmonella</I> strains presented a high concentration of tumor targets in various types of cancer models, suggesting a role as potential vectors for drug delivery. In this study, we genetically engineered an attenuated strain of <I>Salmonella</I> as an anti-invasive vector for the targeted delivery and expression of tissue inhibitor of metalloproteinases 2 (TIMP-2) in an orthotopic nude mouse model of glioma. The bioluminescence signals related to tumor size significantly declined in the TIMP-2-expressing <I>Salmonella</I> (SLpTIMP-2)-treated group compared with the control group. Compared with the control group with a survival rate of an average of 33 days, the SLpTIMP-2 group showed an extended survival rate by nearly 60% and lasted an average period of 53 days with TIMP-2 induction. These results indicated the promising therapeutic potential of <I>S. typhimurium</I> for targeted delivery and secretion of TIMP-2 in glioma.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Intracranial injection of <I>Salmonella</I> has been demonstrated to be a more effective than tail vein injection. </LI> <LI> Treatment with TIMP-2-expressing bacteria showed down regulation of MMP-2 in orthotopic glioma. </LI> <LI> TIMP-2-expressing bacteria significantly inhibited tumor growth and elongated animal survive. </LI> </UL> </P>

A Phase-Shift Modulation Strategy for a Bidirectional CLLC Resonant Converter

Wenmin Hua,Hongfei Wu,Zhiyuan Yu,Yan Xing,Kai Sun 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

A novel phase-shift modulation strategy is applied to a bidirectional CLLC resonant converter (RC). Different from the well-known pulse-frequency modulation strategy, the switching frequency of the CLLC RC is constant, which is beneficial for optimal design and control of the converter. Theoretical analysis proves that voltage gain is independent on load and resonant tank. As a result, topology is optimized with ensuring symmetry of converter. Simulation model is built in Simulink and a 1kW prototype is made. Simulation and experimental results verify the voltage transfer ratio. Dynamic response with load stepping up and down is stable and rapid. In addition, soft-switching of all the power switches can be achieved to reduce switching losses and improve efficiency. Detailed operation principles and characteristics of the modulation strategy are analyzed and verified with experimental results.

A Novel Unsteady Fractal Derivative Creep Model for Soft Interlayerswith Varying Water Contents

Wenmin Yao,Bin Hu,Hongbin Zhan,Chong Ma,Nenghao Zhao 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.12

Creep properties of soft interlayers are key factors associated with the long-term stability of geological bodies. An experimental and theoretical study on the ring shear creep properties of soft interlayers collected from Esheng, Sichuan province, China are performed in this study. Ring shear creep tests of soft interlayers, which are remolded into over-consolidated samples having various water contents and the same initial dry density, are performed in laboratory, to analyze the creep deformation characteristics of samples in detail. The calculated long-term shear strength of samples is close to residual strength. By substituting the dashpot with a new unsteady fractal dashpot, a novel unsteady fractal derivative creep (UFDC) model, which can be defined in series with an improved Maxwell model and an improved viscoplastic model, is proposed based on theory of fractal derivative. The new model can efficiently explain the soft interlayers creep deformation. The results indicate that most model parameters are sensitive to the shear stress. However, at the accelerated creep stage, the fractional order of the second dashpot in the UFDC model has little effect on the fitting of experimental data.

Channel Prediction based MAC Protocol in Cognitive Radio Networks

축문민(Wenmin Zhu),박형근(Hyung-Kun Park) 대한전기학회 2010 전기학회논문지 Vol.59 No.10

Cognitive radio MAC protocol should allow secondary users to access unused or under-utilized spectrum without interference to primary users. For cognitive MAC protocol, one of the important issues is how to select the channel opportunities for secondary users. In this paper, we propose a novel cognitive MAC protocol to allocate channel opportunities for the secondary users based on the prediction of future availability. The proposed MAC protocol can reduce the interference to primary users and increase throughput using multiple channels.

The relative contributions of internal variability and external forcing to Pacific Walker Circulation over the last millennium

Shijie Wang,Wenmin Man,Feng Chen,Meng Zuo 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

Simulating Strength Parameters and Size Effect of Stochastic Jointed Rock Mass using DEM Method

Chong Ma,Wenmin Yao,Yuan Yao,Jun Li 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12

The strength parameters and the size effect of stochastic jointed limestone rock mass is investigated in this paper. Based on extensive statistics of joint parameters of rock mass in the research region, the probable distribution of geometric characteristic parameters of discontinuities are obtained by the probability graph method. Then the Monte-Carlo method is used for discontinuities network modeling. In addition, 3DEC software and its built-in FISH programming language are used to establish the stochastic jointed rock mass network model based on discrete element method. Triaxial numerical simulation tests under variable confining pressure are conducted with different model sizes and dip angles of bedding planes. The numerical simulation results indicate that the jointed rock mass exhibits weak anisotropy property and significant size effect when it is cut by stochastic discontinuities; the mechanical strength parameters of rock mass begins to fluctuate distinctly as the model size increases, and tend to be stable once the model size reaches or exceeds 4 m × 4 m × 8 m. Besides, the comprehensive mechanical parameters of rock mass in the research region are determined and failure modes of rock mass are analyzed as well based on the numerical simulation results.

Response of global monsoon to volcanic forcing during the past millennium

Meng Zuoa,Tianjun Zhou,Wenmin Mana 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

Channel Statistical MAC Protocol for Cognitive Radio

Xiang, Gao,Zhu, Wenmin,Park, Hyung-Kun The Korea Institute of Information and Commucation 2010 Journal of information and communication convergen Vol.8 No.1

opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. A dynamical sensing range as a important parameter introduced to maintain the our protocol performance. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

A Fuzzy Identity-Based Signcryption Scheme from Lattices

( Xiuhua Lu ),( Qiaoyan Wen ),( Wenmin Li ),( Licheng Wang ),( Hua Zhang ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

Fuzzy identity-based cryptography introduces the threshold structure into identity-based cryptography, changes the receiver of a ciphertext from exact one to dynamic many, makes a cryptographic scheme more efficient and flexible. In this paper, we propose the first fuzzy identity-based signcryption scheme in lattice-based cryptography. Firstly, we give a fuzzy identity-based signcryption scheme that is indistinguishable against chosen plaintext attack under selective identity model. Then we apply Fujisaki-Okamoto method to obtain a fuzzy identity-based signcryption scheme that is indistinguishable against adaptive chosen ciphertext attack under selective identity model. Thirdly, we prove our scheme is existentially unforgeable against chosen message attack under selective identity model. As far as we know, our scheme is the first fuzzy identity-based signcryption scheme that is secure even in the quantum environment.