Chaotification of complex networks with impulsive control.

This paper investigates the chaotification problem of complex dynamical networks (CDN) with impulsive control. Both the discrete and continuous cases are studied. The method is presented to drive all states of every node in CDN to chaos. The proposed impulsive control strategy is effective for both the originally stable and unstable CDN. The upper bound of the impulse intervals for originally stable networks is derived. Finally, the effectiveness of the theoretical results is verified by numerical examples.

Stabilization of Positive Systems With Time Delay via the Takagi-Sugeno Fuzzy Impulsive Control.

In this study, the Takagi-Sugeno (T-S) fuzzy impulsive control problem is investigated for a class of nonlinear positive systems with time delay. The time delay under consideration is both in the continuous-time dynamics and at the impulsive instants, which can model practical systems more accurately. An impulse-time-dependent copositive Lyapunov function (IDCLF) is constructed, and the Razumikhin technique is adopted to develop conditions that ensure the globally exponential stability of T-S fuzzy positive systems with delayed impulses. The size constraint between the impulse delay and the bound of impulsive intervals is removed. A T-S fuzzy impulsive controller is designed in terms of the solutions to certain vector inequalities that are readily solvable. Numerical examples and a practical example of lipoprotein metabolism and potassium ion transfer model are given to demonstrate the effectiveness, advantages, and practicality of the proposed results.

Adaptive proxy-based sliding mode control for a class of second-order nonlinear systems and its application to pneumatic muscle actuators.

The human-centered robotic systems demand safe and robust controllers in many applications. This paper proposes an adaptive proxy-based sliding mode control approach for a class of typical second-order nonlinear systems. A new PID-type virtual coupling is designed between a virtual proxy and the physical object. Considering the unknown bound of lumped disturbances, an adaptation law is applied to online adjust the gain of a sign function which ensures the proxy to track the reference accurately. By using the Lyapunov theorem, the closed-loop system stability is proved. Both simulations and experiments are conducted to verify the proposed method based on a real-world pneumatic muscle actuator control platform. The results show that the proposed adaptive proxy-based sliding mode control approach presents better tracking accuracy, safety, and robustness than the conventional PID control and sliding mode control.

Formation-containment control of multiple underactuated surface vessels with sampling communication via hierarchical sliding mode approach.

The formation-containment control problem of multiple underactuated surface vessels (USVs) is investigated in this paper. A hierarchical sliding mode control strategy is proposed to solve this problem under sampling communication. The proposed control comprises two layers: a local sliding model control layer and a distributed coordination layer. The local control layer is designed to drive each USV tracking the reference trajectories, and the distributed coordination layer is proposed to generate the reference trajectories satisfying the control objective of formation-containment control. To achieve the formation-containment control of the closed-loop multiple USVs, a sufficient condition is obtained by utilizing the Lyapunov stability and eigenvalue analysis. Finally, a simulation result is provided to show the effectiveness of the proposed hierarchical sliding mode approach.

Guaranteed Cost for an Event-Triggered Consensus Strategy for Interconnected Two Time-Scales Systems With Structured Uncertainty.

This article proposes the design of an event-triggered control strategy for consensus of interconnected two-time scales systems with structured uncertainty. The control design under consideration ensures also that consensus is achieved with an overall guaranteed cost. Since each system involves processes evolving on both fast and slow time scales, two Zeno-free event-triggered mechanisms are designed to independently decide the sampling and transmission instants for the slow and fast states, respectively. As the first step, we design an event-triggering consensus protocol in the ideal/nominal case when the interconnected systems are not affected by uncertainties and the interactions happen over a fixed interaction network. Next, the results are extended in order to take into account structured uncertainties affecting the systems' dynamics. At this step, we go further and we provide sufficient conditions for event-triggering consensus with a guaranteed overall cost. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed theoretical results.

Distributed Event-Triggered Synchronization of Interconnected Linear Two-Time-Scale Systems With Switching Topology.

This article investigates the synchronization problem of interconnected linear two-time-scale systems (TTSSs) with switching topology. By utilizing the Chang transformation, a distributed synchronization protocol is proposed with event-triggered communication. Static and dynamic event-triggered mechanisms are proposed successively, which both contain two separated event-triggering conditions corresponding to the slow and the fast subsystems. The existence of a strictly positive time period between any two successive transmissions is ensured regardless of the initial states. The main difficulty of this study lies in that the state jump and parametric uncertainty appear because of the system transformation. To overcome the difficulty, the system is first modeled as an uncertain hybrid system. Then, the control gain is properly designed by solving Riccati-like equations dependent on the rough bounds of the eigenvalues of communication graph Laplacians, and a piecewise quadratic Lyapunov function is proposed with which the jump caused by the switching topology is subtly evaluated. Sufficient conditions are thus established to achieve the event-triggered synchronization. Furthermore, the results are also extended to solve the synchronization problem of the interconnected impulsive linear TTSSs. Finally, three numerical examples are provided to demonstrate the effectiveness of the proposed theoretical results.

Fixed-Time Synchronization of Competitive Neural Networks With Multiple Time Scales.

In this brief, we investigate the fixed-time synchronization of competitive neural networks with multiple time scales. These neural networks play an important role in visual processing, pattern recognition, neural computing, and so on. Our main contribution is the design of a novel synchronizing controller, which does not depend on the ratio between the fast and slow time scales. This feature makes the controller easy to implement since it is designed through well-posed algebraic conditions (i.e., even when the ratio between the time scales goes to 0, the controller gain is well defined and does not go to infinity). Last but not least, the closed-loop dynamics is characterized by a high convergence speed with a settling time which is upper bounded, and the bound is independent of the initial conditions. A numerical simulation illustrates our results and emphasizes their effectiveness.

Lag-Bipartite Formation Tracking of Networked Robotic Systems Over Directed Matrix-Weighted Signed Graphs.

This article studies the lag-bipartite formation tracking (LBFT) problem of the networked robotic systems (NRSs) with directed matrix-weighted signed graphs. Unlike the traditional formation tracking problems with only cooperative interactions, solving the LBFT problem implies that: 1) the robots of the NRS are divided into two complementary subgroups according to the signed graph, describing the coexistence of cooperative and antagonistic interactions; 2) the states of each subgroup form a desired geometric pattern asymptotically in the local coordinate; and 3) the geometric center of each subgroup is forced to track the same leader trajectory with different plus-minus signs and a time lag. A new hierarchical control algorithm is designed to address this challenging problem. Based on the Lyapunov stability argument and the property of the matrix-weighted Laplacian, some sufficient criteria are derived for solving the LBFT problem. Finally, simulation examples are proposed to validate the effectiveness of the main results.

Output Multiformation Tracking of Networked Heterogeneous Robotic Systems via Finite-Time Hierarchical Control.

This article investigates the finite-time output multiformation tracking (OMFT) problem of networked heterogeneous robotic systems (NHRSs), where each robot model involves external disturbances, parametric uncertainties, and possible kinematic redundancy. Besides, the interactions among robotic systems are described as a directed graph with an acyclic partition. Then, several novel practical finite-time hierarchical control (FTHC) algorithms are designed. The convergence analysis of the closed-loop dynamics is extremely difficult due to the lack of effective analysis methods. Based on the mathematics induction and reductio ad absurdum, a new nonsmooth Lyapunov function is proposed to derive the sufficient conditions and settling time functions. Finally, numerical simulations are performed on the NHRS to verify the main results.

Distributed Control of Nonlinear Multiagent Systems With Unknown and Nonidentical Control Directions via Event-Triggered Communication.

In this paper, the leader-following output consensus problem for a class of uncertain nonlinear multiagent systems with unknown control directions is investigated. Each agent system has nonidentical dynamics and is subject to external disturbances and uncertain parameters. The agents are connected through a directed and jointly connected switching network. A novel two-layer distributed hierarchical control scheme is proposed. In the upper layer, to save the communication resources and to handle the switching networks, an event-triggered communication scheme is proposed, and a Zeno-free event-triggered mechanism is designed for each agent to generate the asynchronous triggering time instants. Furthermore, to avoid the continuous monitoring of the system states, a Zeno-free self-triggering algorithm is proposed. In the lower layer, to handle the unknown control directions problem and to achieve the output tracking of the local references generated in the upper layer, the Nussbaum-type function-based technique is combined with internal model principle. With the proposed two-layer distributed hierarchical controller, the leader-following output consensus is achieved. The obtained result is further extended to the formation control problem. Finally, three numerical examples are provided to demonstrate the effectiveness of the proposed theoretical results.

Impulsive Multisynchronization of Coupled Multistable Neural Networks With Time-Varying Delay.

This paper studies the synchronization problem of coupled delayed multistable neural networks (NNs) with directed topology. To begin with, several sufficient conditions are developed in terms of algebraic inequalities such that every subnetwork has multiple locally exponentially stable periodic orbits or equilibrium points. Then two new concepts named dynamical multisynchronization (DMS) and static multisynchronization (SMS) are introduced to describe the two novel kinds of synchronization manifolds. Using the impulsive control strategy and the Razumikhin-type technique, some sufficient conditions for both the DMS and the SMS of the controlled coupled delayed multistable NNs with fixed and switching topologies are derived, respectively. Simulation examples are presented to illustrate the effectiveness of the proposed results.

[Analysis of reproductive ecological factors of endangered Rhodiola gannanica.] / ç”˜å—çº¢æ™¯å¤©æ¿’å±çš„ç”Ÿæ®–ç”Ÿæ€å­¦å› ç´ åˆ†æž.

To find effective ways for protecting and recovering an endangered species Rhodiola gannanica in Gannan, an important distribution region of this species in the eastern Tibetan Plateau of China, the breeding system, reproductive process, flowering phenological characteristics and other reproductive controlling factors were investigated. The results showed that there was a unique breeding system in R. gannanica, which was dioecious, and male flowers were also bisexual plants in the early stage of flower bud differentiation. While the sac of pistil was aborted in a certain stage with the development of flowers, the bisexual plants only played the role of males' functions. The outcrossing reproduction was observed, the pollination mode was mainly by wind, and the population flowering occurred in the season with abundant precipitation and high temperature. The bud satge appeared in early June, the florescence was in mid-June, and the flourishing florescence was in early July. The flo-wering duration of R. fastigiata was about 36 d, and the fruit ripening began in late August. The flo-wering time and the flowering duration of the bisexual plants were earlier than female plants. Due to the low pollination rate of the female plants, the buds and ovules were damaged and the 1-3 years young plants barely got flowering and fruiting, the rate of flowering and fruiting of the community only reached 11.0% and the rate of seed natural propagation was low (about 2.0%). 20.0%-25.1% buds of female plants were damaged from bud to flowering stages. 51.1%-65.0% flowers were aborted from flowering to fruiting stages. Only 10.1%-21.0% of ovules developed into seeds. The seed production of per female plant was 158.1, seed germination rate was 81.5% under artificial conditions, and seedling survival rate reached 36.0% in the first year. Our results revealed that seed quality was not the key ecological factor, while it was the pollen limitation, low seed production and the survival rate of seedling that resulted in the reproductive success and species endangered situation.

Characterization of transgene integration pattern in F4 hGH-transgenic common carp (Cyprinus carpio L.).

The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgenic common carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies of the pMThGH-transgene and the transgenes were integrated into the host genome generally with concatemers in a head-to-tail arrangement at 4-5 insertion sites. By using a method of plasmid rescue, four hundred copies of transgenes from two individuals of F4 transgenic fish, A and B, were recovered and clarified into 6 classes. All classes of recovered transgenes contained either complete or partial pMThGH sequences. The class I, which comprised 83% and 84.5% respectively of the recovered transgene copies from fish A and B, had maintained the original configuration, indicating that most transgenes were faithfully inherited during the four generations of reproduction. The other five classes were different from the original configuration in both molecular weight and restriction map, indicating that a few transgenes had undergone mutation, rearrangement or deletion during integration and germline transmission. In the five types of aberrant transgenes, three flanking sequences of the host genome were analyzed. These sequences were common carp b-actin gene, common carp DNA sequences homologous to mouse phosphoglycerate kinase-1 and human epidermal keratin 14, respectively.

[Pharmacological stress echocardiography for diagnosing of viable myocardium in severe left ventricular dysfunction].

OBJECTIVE: To compare the safety, sensitivity, specificity and accuracy of low dose dobutamine (Dob), isosorbide dinitrate and their combination in stress echocardiography to predict regional movement recovery after coronary revascularization (CRV) in patients with old myocardial infarction (OMI) and severe left ventricular dysfunction. METHODS: Fourty patients (mean age 52 +/- 8 years, male 39, female 1) with OMI waiting for CRV with mean left ventricular ejection fraction (LVEF) (39.4 +/- 5.1)%, underwent Dob (3, 5 and 10 microg.kg(-1).min(-1)), isosorbide dinitrate (270 +/- 56) microg/min and their combination (nitrate plus Dob 3, 5 microg.kg(-1).min(-1)) stress echocardiography. Twenty-six patients completed follow-up rest two dimension echocardiography (2DE) (6.8 +/- 2.9) months after CRV. RESULTS: During Dob 2DE, side effects rates increased by dosage, the drug even induced ischemia at a dosage of 10 microg.kg(-1).min(-1). When Dob was combined with nitrate, no ischemia happened. Among 272 abnormal segments in 26 patients after CRV, 156 segments showed contractile improvement. In Dob 2DE, both the sensitivity (46.8% to 88.6%) and accuracy (64.1% to 77.9%) increased by dosage gradient, while the specificities decreased from 87.1% to 64.2%. When combined with nitrate, the sensitivities and accuracy were higher than either drugs used alone (P < 0.05). The detecting effect in isosorbide dinitrate + Dob 5 microg 2DE was comparable to that of Dob 10 microg.kg(-1).min(-1) 2DE. CONCLUSIONS: In identifying myocardial viability in patients with OMI and severe left ventricular dysfunction, Dob 5-10 microg.kg(-1).min(-1) 2DE have good detecting effects, but could induce ischemia. When nitrate was combined with Dob, no ischemia happened, and the sensitivity and accuracy improved significantly. Isosorbide dinitrate + Dob 5 microg.kg(-1).min(-1) 2DE has identifying effect comparable to Dob 10 microg.kg(-1).min(-1) 2DE.

[The protective effects of Tong-xin-luo on myocardium and microvasculature after reperfusion in acute myocardial infarction].

OBJECTIVE: To evaluate the protective effects of Tongxinluo on myocardium and microvasculature after reperfusion in patients with acute myocardial infarction. METHODS: The research was performed on the patients with AMI whose initial ECG showed ST segment elevation and the patients received PCI or thrombolysis immediately after onset. These patients were classified randomly into two groups: control group in which the patients were given routine drug treatment (52 cases) and treatment group in which the patients were given routine drug plus Tongxinluo capsule (60 cases). We observed the abnormal movement of the ventricle wall in 2DE, and the change in LVEDV or LVEF on the 1st day, 7th day, 13th day, 3rd month, and 6th month after onset, which were compared with the result of DISA and SPECT for myocardial image. At the same time we also examined the blood NO and MDA levels on the 1st day, the 7th day and 13th day. RESULTS: (1) The recover rate for the abnormal movement of the ventricle segments in the treatment group were 11.86%, 18.12% and 18.79% respectively, which were higher than that of the control group (4.13%, 8.27% and 11.11% respectively) on the 1st week, the 2nd week, and the 1st month. At the 6th month the total recover rate for the abnormal movement of the ventricle segments of Tongxinluo group was 70.03%, which was significantly higher than that of the control group (51.68%). The WMSI was also decreased more than that of the control group. (2) The LVEDV in Tongxinluo group increased by 9.42% one week after onset, which was close to that of the control group (9.59%). There was no significant change (9.40% and 9.42% respectively) after two weeks and one month in Tongxinluo group, whereas it was increased continuously in the control group (11.84% and 12.33%). LVEDV in Tongxinluo group was decrease obviously after three and six months (3.62% and 5.07% respectively), which was close to the original level, whereas the result of the control group remained on a higher level (13.70% and 11.72% respectively). (3) LVEF of the Tongxinluo group was 53.32% before treatment, which was comparable with that of the control group (P = 0.45). There was no significant difference between the two groups after treatment for 1 week, 2 week and 1 month (P = 0.11, P = 0.13, P = 0.18, respectively). LVEF for the two groups was 58.27% and 53.40% respectively after three months and there was a statistical significance (P < 0.01). LVEF for the two groups was 58.33% and 53.82% respectively after 6 months and the difference remained statistically significant (P < 0.05). (4) The 2DE WMSI for the Tongxinluo group was 1.7552 after 12 hours to 24 hours of the CVR and there was no significant difference compared with that of the control group (WMSI = 1.5380, P = 0.6945). After 6 months, the WMSI decreased to 1.3767 in the Tongxinluo group, which was statistically different from that of the control group (WMSI = 1.5380, P < 0.01). The myocardium acquire isotope score index of the Tongxinluo group was 0.6075 at 6 months, which was significantly different from that of the control group (0.8781). (5) Ultrasonic humerus artery examination in static status showed that there was no significant difference on the diameter of blood vessel and the speed of blood stream between Tongxinluo group and control group with. The diameter of the blood vessel after artery pressure in Tongxinluo group was expanded, which was significantly different from that in the static status (P < 0.001) and that in control group (P < 0.001). The diameter of blood vessel after administration of nitroglycerin in both groups was expanded, which was significantly different from that in the static status (P < 0.001 and P < 0.05). However, Tongxinluo group was expand more obviously than that of the control group (P < 0.05). (6) The MDA level of the Tongxinluo group was decreased (all P < 0.05) and the NO level was increased (all P < 0.05) gradually from the 1st week to the 4th week; however, the MDA level of the control group was not decreased until the 4th week (P < 0.05), and the NO level of the control group was increased evidently at the 2nd week (P < 0.05). CONCLUSIONS: (1) After reperfusion in AMI patients, administration of routine drug combined with Tongxinluo is more effective than routine drug alone in the reduction of infarction size. (2) In Tongxinluo group, the recover time and the total recover rate of the abnormal movement of the ventricle segments were higher than the control group, and the WMSI were significantly decreased than the control group. (3) The improvement degree and the recover time on LVEDV in Tongxinluo group was superior to control group. (4) The improvement of LVEF in time and in degree was superior to control group. (5) The blood concentration of the MDA was decreased significantly in Tongxinluo group, while the NO level was increased significantly, and the time was superior to control group significantly.

[Head to head comparison of dobutamine alone and combined with nitrate stress echocardiography and 99mTc-MIBI/18FDG myocardial SPECT image for diagnosis of viable myocardium in patients with severe left ventricular dysfunction].

OBJECTIVE: This study was sought to compare the sensitivity, specificity and accuracy of (1) dual isotope simultaneous acquisition single-photon emission computed tomography (DISA SPECT) myocardial image with (99m)Tc-sestamibi/(18)F-fluorodeoxyglucose ((99m)Tc-MIBI/(18)FDG); (2) low dose dobutamine alone and combined with Isosorbide Dinitrate (ISDN: Isoket) stress two dimensional echocardiography (2DE) to predict regional movement recovery after revascularization (CRV) in patients with old myocardial infarction (OMI) and severe left ventricular dysfunction. METHODS: Twenty-six patients (mean age 51 +/- 8 years, male 25, female 1) with OMI and severe left ventricular dysfunction (mean left ventricular ejection fraction, LVEF (38.6% +/- 4.9%) underwent low dose dobutamine 10 microg x kg(-1) x min(-1) (Dob10 microg) and ISDN (286 +/- 31 microg/min) combined with Dob5 microg (ISDN-Dob 5 microg) 2DE and DISA SPECT within one week. In echocardiogram and DISA SPECT images: the left ventricle (LV) was divided into 16 segments. The semi-quantitative scoring system was used for both images. Myocardial viability was defined as an improvement of at least >or= 1 grade in at least two contiguous segments at rest 2DE after CRV. The viable segments detecting rate with stress 2DE and DISA SPECT were compared. Compared with the results of post-CRV, the sensitivity, specificity and accuracy of detecting viable segments of two methods were calculated. RESULTS: Among 272 abnormal segments in 26 patients, 156 (57.4%) segments showed contractile improvement after CRV. The viable segments detecting rate with DISA SPECT was 72.4% (134/254), which was significantly higher than the contractile improved rate after CRV (P < 0.001). During Dob10 microg 2DE and ISDN-Dob5 microg 2DE, the detecting rates were 65.5% (163/249) and 65.7% (176/268), respectively, which were both comparable to the improved rate after CRV (both P > 0.05). With DISA SPECT, the sensitivity, specificity and accuracy were 93.7%, 55% and 76.8%, respectively. Compared with DISA SPECT, Dob10 microg 2DE showed similar sensitivity (88.6%), specificity (64.2%) and the accuracy (77.9%). When ISDN combined with Dob5 microg, the sensitivity (91.4%), specificity (68.1%) and accuracy (81.4%)were comparable to those of Dob10 microg 2DE and DISA SPECT (all P > 0.05), while the specificity was even higher than DISA SPECT (P < 0.05). CONCLUSION: In identifying myocardial viability in patients with OMI and severe left ventricular dysfunction, DISA SPECT has higher sensitivity, lower specificity and better accuracy. Dob10 microg and ISDN-Dob5 microg 2DE are both equivalent to DISA SPECT in sensitivities, specificities and accuracies, and even higher in specificity in ISDN-Dob5 microg 2DE.

Global synchronization of complex dynamical networks through digital communication with limited data rate.

This paper studies the global synchronization of complex dynamical network (CDN) under digital communication with limited bandwidth. To realize the digital communication, the so-called uniform-quantizer-sets are introduced to quantize the states of nodes, which are then encoded and decoded by newly designed encoders and decoders. To meet the requirement of the bandwidth constraint, a scaling function is utilized to guarantee the quantizers having bounded inputs and thus achieving bounded real-time quantization levels. Moreover, a new type of vector norm is introduced to simplify the expression of the bandwidth limit. Through mathematical induction, a sufficient condition is derived to ensure global synchronization of the CDNs. The lower bound on the sum of the real-time quantization levels is analyzed for different cases. Optimization method is employed to relax the requirements on the network topology and to determine the minimum of such lower bound for each case, respectively. Simulation examples are also presented to illustrate the established results.

Subtractive phage display technology identifies zebrafish marcksb that is required for gastrulation.

In the present study, we used a phage display technique to screen differentially expressed proteins from zebrafish post-gastrula embryos. With a subtractive screening approach, 6 types of single-chain Fv fragments (scFvs) were screened out from an scFv antibody phage display library by biopanning against zebrafish embryonic homogenate. Four scFv fragments (scFv1, scFv3, scFv4 and scFv6) showed significantly stronger binding to the tailbud embryos than to the 30%-epiboly embryos. A T7 phage display cDNA library was constructed from zebrafish tailbud embryos and used to identify the antigens potentially recognized by scFv1, which showed the highest frequency and strongest binding against the tailbud embryos. We acquired 4 candidate epitopes using scFv1 and the corresponding genes showed significantly higher expression levels at tailbud stage than at 30%-epiboly. The most potent epitope of scFv1 was the clone scFv1-2, which showed strong homology to zebrafish myristoylated alanine-rich C-kinase substrate b (Marcksb). Western blot analysis confirmed the high expression of marcksb in the post-gastrula embryos, and the endogenous expression of Marcksb was interfered by injection of scFv1. Zebrafish marcksb showed dynamic expression patterns during embryonic development. Knockdown of marcksb strongly affected gastrulation movements. Moreover, we revealed that zebrafish marcksb is required for cell membrane protrusion and F-actin alignment. Thus, our study uncovered 4 types of scFvs binding to zebrafish post-gastrula embryos, and the epitope of scFv1 was found to be required for normal gastrulation of zebrafish. To our knowledge, this was the first attempt to combine phage display technique with the embryonic and developmental study of vertebrates, and we were able to identify zebrafish marcksb that was required for gastrulation.

Synchronization of continuous dynamical networks with discrete-time communications.

In this paper, synchronization of continuous dynamical networks with discrete-time communications is studied. Though the dynamical behavior of each node is continuous-time, the communications between every two different nodes are discrete-time, i.e., they are active only at some discrete time instants. Moreover, the communication intervals between every two communication instants can be uncertain and variable. By choosing a piecewise Lyapunov-Krasovskii functional to govern the characteristics of the discrete communication instants and by utilizing a convex combination technique, a synchronization criterion is derived in terms of linear matrix inequalities with an upper bound for the communication intervals obtained. The results extend and improve upon earlier work. Simulation results show the effectiveness of the proposed communication scheme. Some relationships between the allowable upper bound of communication intervals and the coupling strength of the network are illustrated through simulations on a fully connected network, a star-like network, and a nearest neighbor network.

[Relationships among expressions of hTERT, MDR1, MRP mRNA, and C-myc protein in non-small cell lung cancer].

BACKGROUND & OBJECTIVE: The latest researches showed that myc protein could up-regulate the expression of human telomerase reverse transcriptase (hTERT), multidrug resistance gene 1(MDR1), multidrug resistance-related protein (MRP) in some kinds of tumors, and hTERT is correlated with efficiency of anti-tumor chemotherapy. This study was to investigate relations among expressions of hTERT, MDR1, MRP mRNA, and C-myc protein in non-small cell lung cancer (NSCLC). METHODS: Expressions of hTERT, MDR1, MRP mRNA in 113 cases of NSCLC tissues were detected by in situ hybridization, expression of C-myc protein was detected by SP immunohistochemistry, their correlations with clinicopathologic features of NSCLC were statistically analyzed. RESULTS: Positive rates of hTERT, MDR1, MRP mRNA, and C-myc protein in NSCLC tissues were 80.5%, 51.3%, 80.5% and 68.1%, respectively. Expressions of MDR1, MRP mRNA, and C-myc protein were significantly related to that of hTERT mRNA (P<0.05). Expression of C-myc protein did not correlate with expression of MDR1 or MRP mRNA. All 4 factors have no correlation with clinicopathologic features of NSCLC (P>0.05). CONCLUSION: Expression of hTERT mRNA may be related to those of MDR1, MRP mRNA, and C-myc in NSCLC. Overexpression of C-myc protein may be one of the molecular regulatory mechanisms of hTERT mRNA.