Characterization and Resistance Mechanisms of A 5-fluorouracil-resistant Hepatocellular Carcinoma Cell Line

Gu, Wei,Fang, Fan-Fu,Li, Bai,Cheng, Bin-Bin,Ling, Chang-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Purpose: The chemoresistance of human hepatocellular carcinoma (HCC) to cytotoxic drugs, especially intrinsic or acquired multidrug resistance (MDR), still remains a major challenge in the management of HCC. In the present study, possible mechanisms involved in MDR of HCC were identified using a 5-fluorouracil (5-FU)-resistant human HCC cell line. Methods: BEL-7402/5-FU cells were established through continuous culturing parental BEL-7402 cells, imitating the pattern of chemotherapy clinically. Growth curves and chemosensitivity to cytotoxic drugs were determined by MTT assay. Doubling times, colony formation and adherence rates were calculated after cell counting. Morphological alteration, karyotype morphology, and untrastructure were assessed under optical and electron microscopes. The distribution in the cell cycle and drug efflux pump activity were measured by flow cytometry. Furthermore, expression of potential genes involved in MDR of BEL-7402/5-FU cells were detected by immunocytochemistry. Results: Compared to its parental cells, BEL-7402/5-FU cells had a prolonged doubling time, a lower mitotic index, colony efficiency and adhesive ability, and a decreased drug efflux pump activity. The resistant cells tended to grow in clusters and apparent changes of ultrastructures occurred. BEL-7402/5-FU cells presented with an increased proportion in S and G2/M phases with a concomitant decrease in G0/G1 phase. The MDR phenotype of BEL-7402/5-FU might be partly attributed to increased drug efflux pump activity via multidrug resistance protein 1 (MRP1), overexpression of thymidylate synthase (TS), resistance to apoptosis by augmentation of the Bcl-xl/Bax ratio, and intracellular adhesion medicated by E-cadherin (E-cad). P-glycoprotein (P-gp) might play a limited role in the MDR of BEL-7402/5-FU. Conclusion: Increased activity or expression of MRP1, Bcl-xl, TS, and E-cad appear to be involved in the MDR mechanism of BEL-7402/5-FU.

Base Instability Triggered by Hydraulic Uplift of Pit-in-Pit Braced Excavations in Soft Clay Overlying a Confined Aquifer

Fu-quan Chen,Guangji Miao,Fengwen Lai 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.6

The aim of this study is to investigate the coupling effects of re-excavation and hydraulic uplift on base instability of pit-in-pit (PIP) braced excavations. The numerical model of PIP braced excavation in Shanghai soft clay overlying a confined aquifer was established by upper-bound finite element limit analysis (UBFELA) method. The effects of the sensitive design parameters (i.e., the artesian pressure, thickness and undrained shear strength of the aquitard and excavation width of inner pit) on failure mechanisms and upper-bound safety factor (FS) against hydraulic uplift were analyzed. The results show that the value of FS increases with an increase in the thickness and undrained shear strength of the aquitard, but decreases with increasing the artesian pressure and excavation width of inner pit. The failure modes can be typically classified into three categories: circular slip surface in outer pit (M1), hydraulic uplift combined with circular slip surface in entire PIP system (M2), and basal hydraulic uplift in inner pit (M3); then the corresponding critical artesian pressure is determined. Finally, the average value of critical artesian pressure used to distinguish the three types of failure modes is recommended as the design value against hydraulic uplift in the PIP system, and validity is verified by the comparison with the current design methods. The proposed stability design by UBFELA contributes to ensure the serviceability and performance of PIP system.

Ultrastructural and mechanical changes in tubular epithelial cells by angiotensin II and aldosterone as observed with atomic force microscopy

Quan, Fu-Shi,Jeong, Kyung Hwan,Lee, Gi-Ja Elsevier 2018 Micron Vol.110 No.-

<P><B>Abstract</B></P> <P>Tubular epithelial cells (TECs) play an important pathophysiological role in the promotion of renal fibrosis. Quantitative analysis of the mechanical changes in TECs may be helpful in evaluating novel pharmacological strategies. Atomic force microscopy (AFM) is a common nanotechnology tool used for imaging and measuring interaction forces in biological systems. In this study, we used AFM to study ultrastructural and mechanical changes in TECs mediated by the renin-angiotensin-aldosterone system. We quantitatively analyzed changes in the mechanical properties of TECs using three extrinsic factors, namely, chemical fixation, angiotensin II (AT II), and aldosterone (AD). Fixed TECs were 11 times stiffer at the cell body and 3 times stiffer at the cell–cell junction compared to live TECs. After stimulation with AT II, live TECs were four times stiffer at the junctional area than at the cell body, while fixed TECs after AT II stimulation were approximately two times stiffer at the both cell body and cell–cell junction compared to fixed unstimulated TECs. Fixed TECs also reflected changes in the mechanical properties of TECs at the cell body region after AD stimulation. Together, our results suggest that cell stiffness at the cell body region may serve as an effective index for evaluating drugs and stimulation, regardless of whether the cells are live or fixed at the time of analysis. In addition, studying the changes to the intrinsic mechanical property of TECs after application of external stimuli may be useful for investigating pathophysiologic mechanisms and effective therapeutic strategies for renal injury.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We quantitatively analyzed the ultrastructure and mechanical changes in TECs. </LI> <LI> Three extrinsic factors including chemical fixation, AT II and AD treatments were used. </LI> <LI> The mechanical changes in fixed cells after stimuli can reflect those of live cells in cell body region. </LI> <LI> Cell stiffness at cell body region can be utilized as effective index for the evaluation of stimulation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nested Case-control Study of Occupational Radiation Exposure and Breast and Esophagus Cancer Risk among Medical Diagnostic X Ray Workers in Jiangsu of China

Wang, Fu-Ru,Fang, Qiao-Qiao,Tang, Wei-Ming,Xu, Xiao-San,Mahapatra, Tanmay,Mahapatra, Sanchita,Liu, Yu-Fei,Yu, Ning-Le,Sun, Quan-Fu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.11

Medical diagnostic X-ray workers are one occupational group that expose to the long-term low-dose external radiation over their working lifetime, and they may under risk of different cancers. This study aims to determine the relationship between the occupational X-ray radiation exposure and cancer risk among these workers in Jiangsu, China. We conducted Nested case-control study to investigate the occupational X-ray radiation exposure and cancer risk. Data were collected through self-administered questionnaire, which includes but not limits to demographic data, personal behaviors and family history of cancer. Retrospective dose reconstruction was conducted to estimate the cumulative doses of the x-ray workers. Inferential statistics, t-test and 2 tests were used to compare the differences between each group. We used the logistic regression model to calculate the odds ratio (OR) and 95% confidence interval (CI) of cancer by adjusting the age, gender. All 34 breast cancer cases and 45 esophageal cancer cases that detected in a cohort conducted among health workers between 1950~2011 were included in this presented study, and 158 cancer-free controls were selected by frequency-matched (1:2). Our study found that the occupational radiation exposure was associated with a significantly increased cancer risk compared with the control, especially in breast cancer and esophageal cancer (adjusted OR=2.90, 95% CI: 1.19-7.04 for breast cancer; OR=4.19, 95% CI: 1.87-9.38 for esophageal cancer, and OR=3.43, 95% CI: 1.92-6.12 for total cancer, respectively). The occupational X-ray radiation exposure was associated with increasing cancer risk, which indicates that proper intervention and prevention strategies may be needed in order to bring down the occupational cancer risk.

Anisakis 感染 家兎의 時期別 抗體檢出에 대한 각종 抗原의 適用性

全福實(Fu-Shi Quan),鄭明淑(Myung-Sook Chung),朱炅煥(Kyoung-Hwan Joo),林漢鐘(Han-Jong Rim) 한국농촌의학 지역보건학회 1991 농촌의학·지역보건 Vol.16 No.1

무선 애드혹 네트워크에서 다중경로 라우팅을 위한 경로 안정성 측정 방법

장복전(Fu-Quan Zhang),박용진(Yong-Jin Park) 大韓電子工學會 2010 電子工學會論文誌-TC (Telecommunications) Vol.47 No.4

무선 애드혹 네트워크에서 노드들의 이동성은 각각 다르다. 각 경로를 구성하는 노드는 라우터로서 동작하고 있고, 따라서 이러한 노드들이 이동하게 되면 빈번하게 새로운 경로를 탐색해야 한다. 경로를 구성하고 있는 노드 중 일 노드가 높은 이동성을 갖을 경우, 이러한 노드는 경로의 단절을 수시로 야기시키므로 경로 선택에서 최대한 회피해야만 한다. 본 논문에서는 무선 애드혹 네트워크에서 다중경로 라우팅을 위한 경로 안정성 평가를 위해 기존에 알려져 있는 다중경로 라우팅 프로토콜인 Ad hoc on-demand multipath distance vector (AOMDV)를 확장한 한 이동성 인식 방법으로, path stability evaluation (PSE) 프로토콜을 제안한다. AOMDV와 PSE 프로토콜을 ns-2를 통해 비교하였으며, 시뮬레이션 결과에서는 PSE가 패킷 전달, 종단간 딜레이(end-to-end delay) , 라우팅 오버헤드(routing overhead) 및 처리율 측면에서 보다 optimistic한 성능을 보여주고 있음을 증명한다. The mobility of nodes are different in wireless ad hoc networks. Routes have to be refreshed frequently due to the mobility of the nodes acting as routers. Path consists of a few highly mobile nodes should be avoided to forward packets, because even only one highly mobile node may result in the break of path. We develop a mobility aware method to evaluate path stability for multipath routing in wireless Ad Hoc networks. Specifically, we extend it to a well-studied multipath routing protocol known as ad hoc on-demand multipath distance vector (AOMDV). The resulting protocol is referred to as path stability evaluation (PSE). Performance comparison of AOMDV with PSE are studied through ㎱-2. Simulation shows that PSE has optimistic results in performance metrics such as packet delivery, end-to-end delay, routing overhead and throughput..

802.11 무선 네트워크에서 TCP 성능 향상을 위한 기법

장복전(Fu-Quan Zhang),김준환(Jun-Hwan Kim),박용진(Yong-Jin Park) 대한전자공학회 2009 電子工學會論文誌-TC (Telecommunications) Vol.46 No.2

최근 802.11 무선 네트워크에서 TCP성능 향상을 위한 많은 연구가 이루어지고 있다. End-to-end 연결에서 TCP성능을 결정하는 가장 큰 요인으로는 hop-count와 RTT (Round Trip Time) 이다. 본 논문에서는 TCP의 성능을 향상하기 위해, hop-count와 RTT 변경 시 적절한 CWND값을 설정하여 TCP-CEV을 변경하는 기법을 설명한다. 본 논문에서 제안한 기법은 기본 TCP 구조를 따르는 대부분의 transport 프로토콜에 적합하고, 분석적인 과정을 통해 결과를 도출한다. 시뮬레이션을 통해 제안한 기법이 체인 토폴로지에서 12%, 격자 토폴로지에서 4.9% 이상 성능이 향상되었으며, TCP window가 특정 값에 수렴하는 것을 보인다. Improving TCP performance has long been the focus of many research efforts in 802.11 wireless networks study. Hopcount and Round Trip Time (RTT) are the critical sources which serious affect the TCP performance on end?to?end connection. In this paper, we analytical derived the affection and based on the analysis we propose TCP should Change its Expected Value (TCP-CEV) when hop?count and RTT change by setting a reasonable CWND change rate to improve the performance. The proposed scheme is applicable to a wide range of transport protocols using the basic TCP mechanism, and the protocol behavior is analytically tractable. We show that our simple strategy improves TCP performance at least over 12% in a chain topology, 4.9% in a grid topology and improve the TCP convergence.

Tier-based Proactive Path Selection Mode for Wireless Mesh Networks

( Zhang Fu-quan ),( Inwhee Joe ),( Yong-jin Park ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.5

In the draft of the IEEE 802.11s standard, a tree topology is established by the proactive tree-building mode of the Hybrid Wireless Mesh Protocol (HWMP). It is used for cases in which the root station (e.g., gateway) is an end point of the majority of the data connections. In the tree topology, the root or central stations (e.g., parent stations) are connected to the other stations (e.g., leaves) that are one level lower than the central station. Such mesh stations are likely to suffer heavily from contention in bottleneck links when the network has a high traffic load. Moreover, the dependence of the network on such stations is a point of vulnerability. A failure of the central station (e.g., a crash or simply going into sleep mode to save energy) can cripple the whole network in the tree topology. This causes performance degradation for end-to-end transmissions. In a connected mesh topology where the stations having two or more radio links between them are connected in such a way that if a failure subsists in any of the links, the other link could provide the redundancy to the network. We propose a scheme to utilize this characteristic by organizing the network into concentric tiers around the root mesh station. The tier structure facilitates path recovery and congestion control. The resulting mode is referred to as Tier-based Proactive Path Selection Mode (TPPSM). The performance of TPPSM is compared with the proactive tree mode of HWMP. Simulation results show that TPPSM has better performance.

허혈손상망막에 이식된 성체줄기세포의 소재 및 운명

권복실 ( Fu Shi Quan ),신지만 ( Ji Man Shin ),김인범 ( In Beom Kim ),염정은 ( Chung Eun Yeum ),채규태 ( Gue Tae Chae ),천명훈 ( Myung Hoon Chun ),오수자 ( Su Ja Oh ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.4

To investigate the differentiation potency of be engraft mesenchymal stem cells to the retinal cell population through the retina ischemia-reperfusion injury model of rat. Ischemic injury model was made by an elevation of intra-ocular pressure in young adult Sprague-Dawely rats. Adult stem cells of third passages labeled with DiI were applied by an intravitreous injection at 3, 5, and 7 days after the ischemia-reperfusion injury(PI), respectively, cared for 2 weeks, and in case of 7 days PI group were also cared for 4 and 6 weeks. For specification of engraft stem cells, immunofluorescent staining by antibodies against retinal neuronal marker molecules was done. Retinal ischemia led to reduce in both thickness and cell number, principally in the inner retina and to a lesser extent in the outer retina. DiI labeled stem cells were migrated and well associated with host retina tissue by 7 days PI. The retinas of stem cell engraft group were thicker than those of the ischemia group, however, and edematous caused maybe by cell suspension solution volume compared to those of normal control group. Stem cells were located mainly in the ganglion cell layer of 7 days PI engraft group, even though there was no co-localization of DiI and neuronal markers. These results suggest that stem cells influence endogenous neuroprotective mechanisms rather than differentiation into any retinal cell population against neuronal degeneration followed by ischemia injury. It has also been suggested that tissue-specific carriers are necessary for successful transplantation of stem cells into degenerated neral retinas.

Multi-Objective Optimal Allocation for Regional Water Resources Based On Ant Colony Optimization Algorithm

Quan Gan,Fu-Chun Zhang,Ze-Yin Zhang 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.5