Objective To compare the effects of Carvedilol.Bisoprolol therapies for patients with chronic heart failure(CHF). Methods 80 patients with CHF were divided into carvedilol group(40 cases) ,Bisoprolol group (40 cases) ;The two groups were treated respectively with Carvedilol or Bisoprolol in addition to the above conventional therapy. The indicators of heart rate( HR),blood pressure( BP) ,left ventricular end-diastolic diameter( LVEDD) , left ventricular end-systolic diameter( LVESD) ,left ventricular ejection fraction(LVEF) ,6min walking test distance (6min walk) were observed after treatment and before treatment. Results Total effective rates were 82.5% and 87.5% in Carvedilol group and the Bisoprolol group,There was no statistically significant difference between two groups(χ2 =2. 18,P>0.05) ;The indicators of HR,SBP,DBP,LVEDD,LVESD after treatment were lower than before treatment ( all P < 0.05); LVEF, and 6min walk were higher than before treatment (all P < 0.05). Conclusion Bisoprolol and Carvedilol could significantly improve cardiac function in patients with heart failure.

The detection and classification of extracellular action potentials(i.e.spike) of various single neurons from extracellular recordings are crucial for extracting neuronal spike sequences and thereby for investigating the mechanisms of neural information processing in the central nervous system.In order to increase the correctness of spike detecting and sorting,a new analysis algorithm for processing multi-channel spike signals recorded from rat hippocampi with silicon microelectrode arrays is presented.Four recording contacts on the electrode array are arranged close enough to simultaneously record spikes emitted from same neurons.Firstly,the algorithm extracts all spikes in the four channel recordings by using a multi-channel threshold detection method.Secondly,the algorithm classifies the spikes based on a principle component analysis for a specifically designed type of compound spike waveforms.The compound spike waveform is formed by linking four spike waveforms of a same neuronal firing in the four recording channels one by one in series.The test results with both synthetic datasets and experimental recordings reveal that compared with corresponding traditional single-channel algorithm,the multi-channel algorithm can significantly enhance both the number of extracted spikes and the correctness of spike classifications.The algorithm can also increase the number of isolated neurons from a single experimental preparation.These results indicate that the novel method is efficient for the automatic detection and classification of neuronal spikes.

The rapid development of silicon microelectrode arrays provides an ideal means for the study of spatio-temporal features of neuronal activity in the brain. The stability of the linear silicon electrode array (LSEA) in recording neuronal potentials and its validity in recording unit activity are investigated. The experimental results showed that during the recording of field potentials in the hippocampal CA1 region of anesthetized rats, upward and downward movements of the recording probe for a distance of 200 ?m did not affect the orthordromic and antidromic evoked potentials significantly. The data indicated that the probe movements caused very small damage to the neurons, and the recording was stable. The contact sites that located in the pyramidal cell layer acquired CA1 neuronal unit activity validly. Different types of unit activity from independent neurons were easily distinguished in epochs of recording from a same recording site. These results demonstrated the features of the LSEA, including the facility of probe manipulation, the stability of recording and the abundance of data acquirement. The data will be helpful to the researchers involved in the application of microelectrode array for neuroscience researches.

AIM: To establish an animal model of experimental autoimmune myocarditis (EAM) in BALB/c mice and to investigate the expression and significance of Toll-like receptor 3 in mouse EAM. METHODS: BALB/c mice were immunized with cardiac myosin extracted from porcine ventricular myocardium covered by complete freund's adjuvant (CFA) on 0 d and 7 d, then divided into immunized with CFA only. Serum and myocardium samples were collected at 14 d and 21 d after the first immunization. HE staining was used to identify the areas of inflammation. The myosin IgG antibody was examined by indirect ELISA assay. The changes of TLR3 protein and mRNA expression in myocardial tissue were measured by immunohistochemistry and real time-PCR. RESULTS: Compared to control group, immunohistochemistry results showed that there was positive expression of TLR3 in the myocardium of mice with EAM and the mRNA of TLR3 were more than 20 times (P<0.05). The expression of interferon beta mRNA in EAM group was more than 14 times as many as basal expression, that of tumor necrosis factor alpha was more than 18 times (P<0.05). CONCLUSION: The expression of Toll-like receptor 3 in myocardium is up-regulated in experimental autoimmune myocarditis. The inflammatory response to cardiac myosin may associate with the TLR3 signal transduction pathway.

Deep brain stimulation (DBS), which usually utilizes high frequency stimulation (HFS) of electrical pulses, is effective for treating many brain disorders in clinic. Studying the dynamic response of downstream neurons to HFS and its time relationship with stimulus pulses can reveal important mechanisms of DBS and advance the development of new stimulation modes (e.g., closed-loop DBS). To exhibit the dynamic neuronal firing and its relationship with stimuli, we designed a two-dimensional raster plot to visualize neuronal activity during HFS (especially in the initial stage of HFS). Additionally, the influence of plot resolution on the visualization effect was investigated. The method was then validated by investigating the neuronal responses to the axonal HFS in the hippocampal CA1 region of rats. Results show that the new design of raster plot is able to illustrate the dynamics of indexes (such as phase-locked relationship and latency) of single unit activity (i.e., spikes) during periodic pulse stimulations. Furthermore, the plots can intuitively show changes of neuronal firing from the baseline before stimulation to the onset dynamics during stimulation, as well as other information including the silent period of spikes immediately following the end of HFS. In addition, by adjusting resolution, the raster plot can be adapted to a large range of firing rates for clear illustration of neuronal activity. The new raster plot can illustrate more information with a clearer image than a regular raster plot, and thereby provides a useful tool for studying neuronal behaviors during high-frequency stimulations in brain.
Action Potentials ; Animals ; Axons ; physiology ; CA1 Region, Hippocampal ; physiology ; Deep Brain Stimulation ; Neurons ; physiology ; Rats

Currently, commercial devices for electrical neural stimulations can only provide fixed stimulation paradigms with preset constant parameters, while the development of new stimulation paradigms with time-varying parameters has emerged as one of the important research directions for expanding clinical applications. To facilitate the performance of electrical stimulation paradigms with time-varying parameters in animal experiments, the present study developed a well-integrated stimulation system to output various pulse sequences by designing a LabVIEW software to control a general data acquisition card and an electrical stimulus isolator. The system was able to generate pulse sequences with inter-pulse-intervals (IPI) randomly varying in real time with specific distributions such as uniform distribution, normal distribution, gamma distribution and Poisson distribution. It was also able to generate pulse sequences with arbitrary time-varying IPIs. In addition, the pulse parameters, including pulse amplitude, pulse width, interphase delay of biphasic pulse and duration of pulse sequence, were adjustable. The results of performance tests of the stimulation system showed that the errors of the parameters of pulse sequences output by the system were all less than 1%. By utilizing the stimulation system, pulse sequences with IPI randomly varying in the range of 5~10 ms were generated and applied in rat hippocampal regions for animal experiments. The experimental results showed that, even with a same mean pulse frequency of ~130 Hz, for neuronal populations, the excitatory effect of stimulations with randomly varying IPIs was significantly greater than the effect of stimulations with fixed IPIs. In conclusion, the stimulation system designed here may provide a useful tool for the researches and the development of new paradigms of neural electrical stimulations.
Animals ; Electric Stimulation ; Neurons ; Rats

Deep brain stimulation (DBS) has been successfully used to treat a variety of brain diseases in clinic. Recent investigations have suggested that high frequency stimulation (HFS) of electrical pulses used by DBS might change pathological rhythms in action potential firing of neurons, which may be one of the important mechanisms of DBS therapy. However, experimental data are required to confirm the hypothesis. In the present study, 1 min of 100 Hz HFS was applied to the Schaffer collaterals of hippocampal CA1 region in anaesthetized rats. The changes of the rhythmic firing of action potentials from pyramidal cells and interneurons were investigated in the downstream CA1 region. The results showed that obvious θ rhythms were present in the field potential of CA1 region of the anesthetized rats. The θ rhythms were especially pronounced in the stratum radiatum. In addition, there was a phase-locking relationship between neuronal spikes and the θ rhythms. However, HFS trains significantly decreased the phase-locking values between the spikes of pyramidal cells and the θ rhythms in stratum radiatum from 0.36 ± 0.12 to 0.06 ± 0.04 ( < 0.001, paired -test, = 8). The phase-locking values of interneuron spikes were also decreased significantly from 0.27 ± 0.08 to 0.09 ± 0.05 ( < 0.01, paired -test, = 8). Similar changes were obtained in the phase-locking values between neuronal spikes and the θ rhythms in the pyramidal layer. These results suggested that axonal HFS could eliminate the phase-locking relationship between action potentials of neurons and θ rhythms thereby changing the rhythmic firing of downstream neurons. HFS induced conduction block in the axons might be one of the underlying mechanisms. The finding is important for further understanding the mechanisms of DBS.