Mechanism by which endothelin-1 regulates the differentiation of P19 cells into cardiac conduction cells / 中国组织工程研究

BACKGROUND: Endothelin-1, as a paracrine cytokine derived from endocardium and vascular endothelial cells, can promote the differentiation and maturation of cardiac conduction cells. OBJECTIVE:To explore the effect of endothelin-1 on P19 cells differentiating into cardiac conduction cells in vitro. METHODS: P19 cells were cultured with 1% dimethyl sulfoxide or 100 nmol/L endothelin-1. Afterwards, the changes of early cardiomyocyte transcription factors MEF2C and GATA4, differentiation markers MHC-α and cTnT, important conduction cell transcription factors Nkx2.5 and Tbx5, and differentiation markers Cx40 and ANP were identified by western blot assay, immunofluorescence and real-time PCR. Specific antagonists of endothelin-1 receptors, and blocking PI3K-AKT-mTOR signaling pathway on the differentiation of P19 cells induced by endothelin-1 were evaluated by real-time PCR. RESULTS AND CONCLUSION: Endothelin-1 significantly up-regulated the levels of early cardiac transcription factors, cardiomyocyte structure factors and characteristic conduction system markers. Compared with dimethyl sulfoxide, endothelin-1 was prone to enhance the differentiation of cardiac conduction cells derived from P19 cells. Up-regulation of Nkx2.5 and Cx40 by endothelin-1 was mainly attributed to the ETAsignaling pathway. ETBsignaling pathway may be also involved in a negative feedback regulation pathway. The PI3K-AKT-mTOR signaling pathway can play an important role in the differentiation from P19 cells to cardiac conduction cells triggered by endothelin-1.

The study on local field potentials in rat's primary motor cortex during pressing paddle behavior / 中国应用生理学杂志

<p><b>OBJECTIVE</b>The local field potential (LFP) is a summation of dendritic potentials. The main objective of the present work is to view the features of LFP in M1 during the experimental rat pushed a paddle with the right forelimb.</p><p><b>METHODS</b>Four rats were trained to press a paddle with the right forelimb for water. Then Two bundle micro-electrode with four channels were implanted into the rat's left and right primary motor cortex (M1)(AP + 3.0 mm, ML +/- 1.6 mm, H-1.6 mm) with stereotaxic apparatus. After three days recovery, 8-channel Deep-EEG and the pulse signal of paddle pressed were recorded during the rats were in operant chamber, and at the same time, the behavior were also recorded with video recorder.</p><p><b>RESULTS</b>The LFP in left M1 were defined as the substance between two channel deep-EEG. It is found that low frequency, high amplitude signal appear aligned with the paddle pressed pulse signals. With threshold detect method, about 80% press-paddle behavior could be detected.</p><p><b>CONCLUSION</b>The result indicates that LFPs in this position in M1 are relative to forelimb's movement, and a powerful brain-computer interface system maybe developed with the LFPs.</p>

Effect of environment temperature on the recovery of microdialysis probe for monoamine neurotransmitter / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of environment temperature on the recovery of microdialysis probe for neurotransmitters.</p><p><b>METHODS</b>Neurotransmitters NE, DA, and 5-HT were dialyzed with 4 mm membrane length microdialysis probes in different environmental temperature. There were three conditions: lower temperature condition, the temperature of standard solution and that of the perfusate were both 24 degree; higher temperature condition,both were 37.5 degree; and the middle temperature:the perfusate was 24 degree and the standard solution was 37.5 degree. The concentrations of neurotransmitters in the dialyzed solution and the standard solution were analyzed by HPLC-ECD, and recoveries were then calculated.</p><p><b>RESULT</b>In lower temperature condition,the recoveries of microdialysis probe for NE, DA, 5-HT were 18.3 %, 19.6% and 16.9%, respectively. In middle temperature condition, the recoveries were 29.6%, 30.7% and 24.3%, respectively, and in higher temperature condition, those were 49.2%, 47.5% and 37.2%, respectively. With the analysis of variance, the recoveries for NE, DA, 5-HT increased with temperature significantly (P<0.01).</p><p><b>CONCLUSION</b>Both the perfusate and the standard solution affects the environmental temperature of microdialysis probe, which in turns affects the recovery of microdialysis probe for neurotransmitters. So in order to calculate the recovery more accurately, the standard solution/the perfusate should be kept in body temperature.</p>

Effect of dialysis time in vivo on recovery of amino acids for micro-dialysis probe / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the variety of vitro recovery of amino acids for microdialysis probe after different dialysis time in vivo.</p><p><b>METHODS</b>Probes were dialyzed in the amino acids standard solutions with microdialysis system,amino acid standard solutions and the microdialysate of probe were detected by the method of precolumn derivation with HPLC-RF.</p><p><b>RESULT</b>After using different time of probe made by regenerated cellulose membrane, the vitro recoveries of Asp, Glu and GABA were not completely same (Asp: F=19.669, P=0.000; Glu: F=103.955, P=0.000; GABA: F=3.454, P=0.040); while the vitro recovery of Tau had no obvious difference(F=2.001, P=0.152). After using 6 h in vivo, recovery remain percentage (RRP) of Asp, Glu,Tau and GABA was 64.34 %, 67.36%, 103.11 % and 98.23 %, respectively, the recoveries of Asp, Glu decreased obviously (Asp: P < 0.01,Glu: P <0.05). After using 12 h in vivo, the RRP of Asp, Glu, Tau and GABA was 43.44 %, 24.42%, 77.45 % and 67.36 %, respectively, the recoveries of Asp, Glu and GABA decreased obviously (Asp: P < 0.001, Glu: P < 0.001, GABA: P < 0.05). After using 24 h in vivo, the RRP of Asp, Glu,Tau and GABA was 36.26 %, 12.24 %, 89.48 % and 71.35 %, respectively, the recoveries of Asp, Glu, GABA decreased obviously (Asp: P < 0.0001, Glu: P < 0.0001, GABA: P < 0.01).</p><p><b>CONCLUSION</b>Dialysis in vivo could lead to the decline of recovery of probe, the decline is more obvious after longer dialysis. So when making brain dialysis experiments, the use time of probe should not be too long. To improve the validity of data, some calibration should be made on the recoveries of probe.</p>

Inhibitory effects of jujuboside A on EEG and hippocampal glutamate in hyperactive rat / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In this study, the inhibitory effect of jujuboside A (JuA) on a penicillin sodium (Na-PCN) induced hyperactivity model was investigated. Cortical EEG (electroencephalogram) and the concentration of hippocampal Glutamate (Glu) were monitored simultaneously in vivo as indicators of rat's excitatory state. Power spectral density (PSD) and gravity frequency of PSD were calculated. JuA (0.05 g/L and 0.1 g/L) inhibited the EEG excitation effect caused by Na-PCN by increasing the power of delta1 and delta2 bands (P<0.01 vs model) and lowering the gravity frequency of PSD (P<0.01 vs model). JuA also remarkably reduced the Glu elevation induced by Na-PCN (P<0.05 vs model). Diazepam also depressed Glu concentration and lowered the gravity frequency, but it showed a different EEG pattern in increased beta2-activity (P<0.01 vs model). EEG excitation caused by Na-PCN correlated with Glu elevation during the first hour. Neurophysiological inhibitory effects of JuA and diazepam were more persistent than their Glu inhibitory effects.

Automated recognition and identification of soft tissue landmarks in cephalematric analysis / 浙江大学学报·医学版

OBJECTIVE: To establish the automatic x-ray cephalometric analysis system to provide the convenient and reliable method for clinical cephalometric analysis. METHODS The graphics, image processing techniques and artificial intelligence was usedand the computer digital image processing and pattern recognition such as median filtering, histogram equalization, Laplacian and Canny edge detection were introduced. To provide the templates of the variable anatomical structures, which could automatically outline the contour lines of the hard and soft tissues. Thirty five cases were measured and analysied with the system. RESULTS: The computer measurements had the same consistency with hand measurements. The system could calculate more precisely and save more time and energy than other systems. CONCLUSION: The system can supply a more convenient and precise measurement for cephalometry.