• 제목/요약/키워드: orthopedics

검색결과 638건 처리시간 0.033초

Research Progress on the Livin Gene and Osteosarcomas

  • Li, Cheng-Jun;Cong, Yu;Liu, Xiao-Zhou;Zhou, Xing;Shi, Xin;Wu, Su-Jia;Zhou, Guang-Xin;Lu, Meng
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권20호
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    • pp.8577-8579
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    • 2014
  • Osteosarcoma is a common malignant tumor of bone, but mechanisms underlying its development are still unclear. At present, it is believed that the inhibition of normal apoptotic mechanisms is one of the reasons for the development of tumors, so specific stimulation of tumor cell apoptosis can be considered as an important therapeutic method. Livin, as a member of the newly discovered inhibitor of apoptosis proteins (IAPs) family, has specifically high expression in tumor tissues and can inhibit tumor cell apoptosis through multiple ways, which can become a new target for malignant tumor treatment (including osteosarcoma) and might of great significance in the clinical diagnosis of tumors and the screening of anti-tumor agents and carcinoma treatment.

Correlation between E-Cadherin-Regulated Cell Adhesion and Human Osteosarcoma MG-63 Cell Anoikis

  • Lin, Ding-Sheng;Cai, Le-Yi;Ding, Jian;Gao, Wei-Yang
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권19호
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    • pp.8203-8207
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    • 2014
  • Purpose: The aim of this study was to investigate the relationship between cell adhesion and anoikis evasion among human osteosarcoma cells (MG-63), and to further study the molecular mechanisms. Materials and Methods: Human osteosarcoma cells (MG-63) were assessed for apoptosis, and caspase-3, E-cadherin and ${\beta}$-catenin expression in EDTA and control non-EDTA groups. Results: MG-63 cells were predominantly aggregated when in suspension, and the suspended cells were more dispersed in the EDTA group. Following culture in suspension for 24 h, 48 h, or 72 h, the rates of apoptosis were $34.88%{\pm}3.64%$, $59.3%{\pm}7.22%$ and $78.5%{\pm}5.21%$ in the experimental group and $7.34%{\pm}2.13%$, $14.7%{\pm}3.69%$, and $21.4%{\pm}3.60%$ in the control group, respectively. Caspase-3 expression progressively increased and E-cadherin and ${\beta}$-catenin were decreased in the experimental group, whereas there was no change in the control group. Conclusions: MG-63 cells could avoid anoikis through cell adhesion, and E-cadherin might play a role in this process.

LY294002 Induces G0/G1 Cell Cycle Arrest and Apoptosis of Cancer Stem-like Cells from Human Osteosarcoma Via Down-regulation of PI3K Activity

  • Gong, Chen;Liao, Hui;Wang, Jiang;Lin, Yang;Qi, Jun;Qin, Liang;Tian, Lin-Qiang;Guo, Feng-Jing
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권7호
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    • pp.3103-3107
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    • 2012
  • Osteosarcoma, the most common primary mesenchymal malignant tumor, usually has bad prognosis in man, with cancer stem-like cells (CSCs) considered to play a critical role in tumorigenesis and drug-resistance. It is known that phosphatidylinositol 3-kinase (PI3K) is involved in regulation of tumor cell fates, such as proliferation, cell cycling, survival and apoptosis. Whether and how PI3K and inhibitors might cooperate in human osteosarcoma CSCs is still unknown. We therefore evaluated the effects of LY294002, a PI3K inhibitor, on the cell cycle and apoptosis of osteosarcoma CSCs in vitro. LY294002 prevented phosphorylation of protein kinase B (PKB/Akt) by inhibition of PI3K phosphorylation activity, thereby inducing G0/G1 cell cycle arrest and apoptosis in osteosarcoma CSCs. Further studies also demonstrated that apoptosis induction by LY294002 is accompanied by activation of caspase-9, caspase-3 and PARP, which are involved in the mitochondrial apoptosis pathway. Therefore, our results indicate PI3K inhibitors may represent a potential strategy for managing human osteosarcoma via affecting CSCs.

Design of BLDC Motor Controller for Electric Power Wheelchair

  • Chu, Jun-Uk;Moon, In-Hyuk;Choi, Gi-Won;Ryu, Jei-Cheong;Mun, Mu-Seong
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.1509-1512
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    • 2003
  • The electric power wheelchair needs to control motor torque and speed for responding to variable actions given by handling a joystick. In this paper a DSP-based BLDC motor controller using a single dc-link current sensor is presented for electric power wheelchair. It is composed by a DSP processor and three-phase inverter module. To control torque, high speed current control is achieved by the PI controller and pulse width modulation (PWM) signals with 25 kHz carrier frequency, which is performed by 200 ${\mu}sec$ cycle. The speed controller computes the new direct current reference from the speed error and the PI control equation. The displacement value by handling the joystick is converted to reference speeds of right and left wheel motors using nonholonomic wheelchair kinematics. Experimental results show that the presented control system is enough to implement a speed servo in wheelchair driving.

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Actuation of Artificial Muscle Based on IPMC by Electromyography (EMG) Signal

  • Lee, Myoung-Joon;Jung, Sung-Hee;Moon, In-Hyuk;Lee, Suk-Min;Mun, Mu-Sung
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.1173-1178
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    • 2005
  • This paper proposes an IPMC actuating system with a bio-mimetic function. EMG signals generated by an intended contraction of muscles in forearm are used for the actuation of the IPMC. To obtain higher actuation force of the IPMC, the single layered as thick as 800 [${\mu}$m] or multi-layered IPMC (Nafion) of which each layer can be as thick as 178 [${\mu}$m] are prepared. The experimental results using an implemented IPMC control system show a possibility and a usability of the bio-mimetic artificial muscle.

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고령자 보행보조로봇 제어기법 연구 (Research of Elderly Gait-assistant-robot Control System)

  • 최혁재;강성재;권칠용;류제청;이석민;문무성
    • 제어로봇시스템학회논문지
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    • 제16권9호
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    • pp.823-826
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    • 2010
  • In this study, the control method of assistive robot was developed for the elderly. The control method of gait-assistant-robot was proposed considering the change of COP (Center of Pelves), BOS (Base of Support) and comparative analysis of the moving velocity for the elderly. We analyzed the movement of COP of the body and its velocity of the elderly equipped with manual walker and gait-assistant-robot. As a result, change in COP was greater from left to right than from anterior to posterior; also, the average velocity of the movement of COP and manual walker for manual walker gait was 0.7(m/s). Therefore, it is necessary to concern more on the left-right balance and synchronization of the velocity of COP.