Are you W.H. Xu?

Claim your profile

Publications (4)0 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the present study is to investigate the effect of Dendranthema morifolium (DrVI) on isolated rat heart and ventricular myocytes during ischemia/anoxia and reperfusion/reoxygenation. The Langendorff perfused rat hearts were used to measure intraventricular pressure and coronary flow. The cell contraction in enzymatically isolated ventricular myocytes was determined by a video tracking system. DM significantly attenuated the inhibitory effects induced by ischemia/reperfusion on left ventricular developed pressure (LVDP), ±dP/dtmax, coronary flow and LVDP×HR. DM attenuated the inhibitory effects of anoxia and reoxygenation on cell contraction in isolated ventricular myocytes. The results suggest that DM processes cardioprotective effect during ischemia/anoxia and reperfusion/reoxygenation in the isolated rat heart and the ventricular myocytes.
    Engineering in Medicine and Biology Society, 2003. Proceedings of the 25th Annual International Conference of the IEEE; 10/2003
  • [Show abstract] [Hide abstract]
    ABSTRACT: By using Langendorff perfused rat heart and enzymatically isolated cardiomyocytes, we investigated the augmented injury effect of iron on the myocardium by hydrogen peroxide and the underlying mechanisms. Cell-permeable iron (Fe-HQ) decreased the contractile amplitude, velocity and end-diastolic cell length of the cardiomyocyte but increased the contents of lactate dehydrogenase (LDH) and creatine kinase (CK) in the coronary effluent and the myocardial malondialdehyde (MDA) while the left ventricular developed pressure (LVDP), +/-dp/dt(max), heart rate and coronary flow showed biphasic alterations. Hydrogen peroxide augmented the injury effect of iron accompanied by increases of coronary LDH, CK release and myocardial MDA content and decreases of LVDP, +/-dp/dt(max), and heart rate. Reduced glutathione could antagonize the injury effect of iron and hydrogen peroxide on the myocardium while dimethyl sulfoxide had no injury effect on the isolated heart. It is suggested that the functional injury of sulfhydryl group containing proteins may be involved in the augmentation of myocardial injury due to the increase of intracellular iron by hydrogen peroxide, but hydroxyl radicals may not.
    Sheng li xue bao: [Acta physiologica Sinica] 07/2001; 53(3):175-82.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the present study was to determine the alterations of contraction parameters in isolated cardiomyocytes under anoxia and reoxygenation by using a video tracking system developed by us and examine the pharmacological application of this system to determine the effect of Salvia miltiorrhiza (SM) on anoxia and reoxygenation-induced mechanical changes. The results showed that the parameters measured were stable and consistent with those determined by other commercial device. Anoxia and reoxygenation reduced the peak velocity of cell shortening/relengthening (+/- dL/dtmax), the amplitude of contraction (dL) and the end-diastolic cell length of the isolated ventricular myocyte. Under normoxia SM alone also decreased the parameters, but under anoxia followed by reoxygenation SM attenuated the alterations of the contraction parameters. The results indicate that the video tracking system is a valuable tool for analyzing the mechanical events of cardiomyocytes and SM could protect cardiomycytes against the deterioration of contraction function induced by anoxia and reoxygenation.
    Engineering in Medicine and Biology Society, 2001. Proceedings of the 23rd Annual International Conference of the IEEE; 02/2001
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiac gap junctions (GJs) form low resistance pathways along which the electrical impulse flows rapidly and repeatedly between all the cells of the myocardium, enabling coordinated contraction of the heart. In many heart diseases, electrical coupling through GJ channels between cardiomyocytes is down regulated. We set up a mathematical model of a chain of myocardial fibers to study how changing the coupling affects the activity of autorhythmic myocytes. While uncoupling blocked the propagation of excitation from autorhythmic myocytes to surrounding quiescent but excitable cells, different degrees of uncoupling increased the automaticity of the cells. Our modeling data suggests that the number of autorhythmic cells plays a key role in the excitation of autorhythmic cells and the conduction of impulses. We conclude that the degree of uncoupling between cardiomyocytes, induced by pathological processes, may generate ectopic foci, tachyarrhythmias being the outcome.
    Engineering in Medicine and Biology Society, 2001. Proceedings of the 23rd Annual International Conference of the IEEE; 02/2001