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BACKGROUND: The study of cell transplantation to repair injured cardiac muscle and improve cardiac function of dilated cardiomyopathy (DCM) has become a hotspot in recent years. However, the effect of cardiac electrophysiology following transplantation is still unknown.OBJECTIVE: To explore the influence of ailogenic implanted mesenchymal stem cells (MSCs) on cardiac function, structure and electrophysiology of rabbits with DCM.DESIGN, TIME AND SETTING: Randomized controlled animal trial was performed at Electrophysiology Laboratory of Institute of Pediatrics, Chongqing Medical University between January 2004 and May 2006.MATERIALS: Forty-three New Zealand whiterabbits, weighing 3.0-3.5 kg, irrespective of gender, were selected. Adriamycin was produced by Haizheng Medical Products Company of Zhejiang Province, China, No. 050307. The Ultrasonograph SSD-5000 came from Aloka, Japan, and RM6240 multiplying channel electrophysiolograph of Chengdu Instrument Company was applied.METHODS: All animals were randomized into normal group (n=12), cell transplantation group (n=13), and DCM model group (n=13). Except the normal group, adriamycin was applied to create rabbit DCM model, I mg/kg, twice a week for successive 8 weeks. Bone marrow solution was harvested from the remaining 5 rabbits, and MSCs were isolated, amplified and purified using attachment method. Three weeks after modeling, the MSCs were transplanted into left ventricle anterior wall at four sites in cell transplantation group, model group was injected with matching DMEM/FI2 medium, while the normal group was not given any treatment.MAIN OUTCOME MEASURES: At four weeks postoperatively, left ventricular end-diastolic dimension, end systolic dimension,left ventricular ejection fraction, and shortening fraction were monitored by ultrasonograph; the value for monophasic action potential amplitude (MAPA) and the maximum velocity in 0 phase (V,,~), the value for 50% monophasic action potential durations (MAPDs0) and 90% monophasic action potential durations (MAPDg0) were detected by electrophysiolograph. In addition, the cardiac tissues harvested from implanted region were observed by light microscope and electron microscope, and also the expression of cardiac troponin T (cTnT) and connexin 43 (Cx43) was detected through immunohistochemistry.RESULTS: Of 43 rabbits, 9 rabbits each of the transplantation group died of the acute or chronic toxic effects of Adriamycin, finally, 25 rabbits were included in final analysis. Compared with model group, the end systolic dimension was diminished, and the left ventricular ejection fraction and shortening fraction in cell transplantation group were significantly increased (P ＜ 0.05). The MAPDs0 and MAPDgo in cell transplantation group prolonged significantly compared with model group (P ＜ 0.05). In model group,cardiac myocytes appeared mitochondria swelling and hyperplasia, and their sarcomere had different lengths, arranged unevenly,accompanied by abnormal contraction bands. In addition, myolysis was found in parts of myocardium under electron microscope.However, the structural abnormalities in the cell implantation group were less than the DCM model group, and the implanted MSCs could express cTnT and Cx43.CONCLUSION: Allogenic MSCs transplantation can improve cardiac function, lessen structural abnormalities and may inhibit the progression of electrophysiology derangement.
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OBJECTIVE：Analyzing the epidemic of drug risistance bacteria with extend spectrum β-lactamase(ESBLs)in children's wards to cut off the transmitting pathway and prevent the outbreak of nosocomial infections in time.METHODS：Samples，including sputum，umbilical secretion，pus，pharyngeal swab，were collected from in-hospital child patients in Departments of Newborn，Respiratory Tract Diseases，Cardiology，Nephrology，Hematology，Pediatric Surgery and ICU，then bacterial cultures and drug susceptibility test were carried out.54 strains of ESBLs E.coli and Klebsiella pneumoniae were isolated and their plasmid profiles were analysed by agarose electrophoresis.RESULTS：The percentages of ESBLs in the above-mentioned departments were 46.3，12.9，5.6，12.9，5.6，11.1，5.6 respectively.In analysis，three types of profiles were found and strains with four types of the same profile concentrated in the Newborn Department.The others were dispersed.CONCLUSION：Nosocomial infections possibly occured in the Newborn Department to some extent.
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Objective To observe the effect of ambroxol on the structure of Pseudomonas aeruginosa biofilm (BF) in an established biofilm model in vitro. Method Mature BF was formed after 7 days′ culture of Pseudomonas aeruginosa on plate. The BF structure was observed by scanning electron microscope (SEM). The parameters of BF structure were analyzed though pictures from confocal laser scanning microscopy (CLSM) with Image Structure Analyzer (ISA) software. Fluorescence intensity of the viable bacteria in BF treated by ambroxol alone and together with ciprofloxacin were determined with fluorescence microscopy. Results After the treatment of ambroxol, the BF was destroyed and the matrix outsides became thin and abnormal compared with the control by SEM, and small amount of bacteria dispersed. The results of ISA showed that with the treatment of 2 mg/ml ambroxol, BF was decreased in thickness, average diffusion distance (ADD) and textual entropy (TE) were decreased in comparison with the group without ambroxol treatment (P
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Objective To explore whether the neurons induced from mesenchymal stem cells(MSCs) have synapse function or not.Methods Passage 4-5 MSCs in good shape was induced by Salvia miltiorrhiza with optimized protocol for several times,and then the observation under inverted phase contrast microscope,immunofluorocytochemistry and the measurement of neurophysiological function were carried out.Ca2+ influx and synapse function were detected with laser-scanning confocal microscopy(LSCM),taking 50 mmol/L KCl as stimuli to evoke action potential.Results The cells that had been induced for 5 h at 4th time from MSCs,looked like neurons and displayed that the processes stretched out to form complex net.Immunofluorocytochemistry presented that the rate of TUJ-1 expression was(96.7?2.8)% and that of synaptophysin was(96.2?2.1)%.When the neuron-like cells were stimulated by high concentration of KCl,intracellular Ca2+ influx enhanced quickly.When the neuron-like cells were stimulated by high KCl solution for the first time,SynaptoRed-C2 anchored onto the membrane,and after the second excitation,the fluorescence intensity decreased quickly.Conclusion The neuron-like cells derived from MSCs that are induced by salvia miltiorrhiza with optimized protocol have synapse function.
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Objective To explore the distribution and differentiation of bone mesenchymal stem cells (MSCs) in the brain of neonatal rats with hypoxic ischemic encephalopathy (HIE). Methods MSCs were isolated and purified by adhering to the culture glassware wall and prelabeled with bromodeoxyuridine (BrdU) for 72 h before transplantation. The model of HIE was established. At 24 h after hypoxic ischemia, approximate 4?10 6 cells were injected into the brain of neonatal rats with HIE through the right side bregma. The Nestin, neuron specific enolase (NSE) and glial fibrillary acid protein (GFAP) were detected by immunofluorochemistry at 4 weeks after injection. Results Majority of MSCs were distributed in the cortex, hippocampus of the lesioned hemisphere. The number of MSCs was (2781?254) in the left hemisphere, but (4708?281) in the right hemisphere. There was significant difference (t=18.70, P0.05). The expression ratio of NSE was (3.79?0.95)% in the left hemisphere, but (5.69?1.48)% in the right hemisphere (t=3.404, P0.05). Conclusion MSCs are mainly distributed in the lesioned hemisphere and can differentiate into neuronal-like cells, express the mark of neural stem cells, neurons and neuroglial cells at 28 d after intracortical transplantation.