Effects of vagal stimulation on monophasic action potentials (MAP) and transmembrane potentials (TMP) of hyperkalemic rabbit heart were investigated. The results showed that ventricular conduction block induced by hyperkalemia can be improved by vagal stimulation. Amplitude of MAP (MAPA) and maximum rate of rise of MAP (MVmax) were increased, durations of MAP(MAPD) lengthened. Also in single ventricular cell amplitude of action potential (APA) and maximum rate of rise of action potential (Vmax) were increased, while durations of action potential (APD) lengthened. In addition, MAPD and APD measured at the same site are completely in accordance.

Objective To explore and develop a close-chest animal model of acute myocardial infarction (AMI) with left ventricular aneurysm. Methods After anesthesia, 2.0 mm or 2.5 mm angioplasty balloon was positioned in the mid-LAD distal to the first diagnonal branch. The balloon was inflated and occluded the LAD for 150 minutes. ECG and blood pressure were monitored. UCG, cTnI and coronary angiography were also investigated to confirm AMI and the aneurysm. Results Five of seven pigs underwent successful induction of AMI and aneurysm. Two of seven pigs died of ventricular fibrillation. The dynamic changes of ECG and cTnI further confirmed AMI. Regional wall-motion abnormalities were found by two-dimensional echocardiography one hour after AMI and left ventricular aneurysm two weeks later in all pigs. Conclusion A closed-chest pig model of aneurysm after AMI is feasible and has a relatively high induction rate and a low mortality.

BACKGROUND:Previous study reveals that,glycated albumin plays an important role on the apoptosis of endothelial cells and the expression of monocyte chemoattractant protein-1 through increasing the activity of mitogen activated protein kinase and protein tyrosine kinase,besides generating active oxygen products. OBJECTIVE:To investigate the effects of glycated albumin on the expression of monocyte chemoattractant protein-1 in the cultured human umbilical vein endothelial cells(HUVECs) . DESIGN,TIME AND SETTING:A single sample observation was carried out in the Cardiovascular Laboratory of Southeast University(Nanjing,Jiangsu,China) from May to November in 2006. MATERIALS:ECV304 HUVEC strain was provided from Shanghai Institute of Cell Biology,Chinese Academy of Sciences(China) . METHODS:Experimental procedures were assigned to two parts. On one hand,HUVECs were cultured with glycated albumin of the concentration of 400 mg/L for 0,8,16,24,48,or 72 hours. On the other hand,HUVECs were cultured with glycated albumin of the concentrations of 100,200,400,and 800 mg/L for 24 hours. In the control group,HUVECs were incubated with bovine serum albumin of the concentration of 400 mg/L and RPMI 1640 culture medium without addition of the serum. MAIN OUTCOME MEASURES:The proliferation of HUVECs was estimated by MTT colorimetric assay. The content of monocyte chemoattractant protein-1 in the supernatant was measured by enzyme-linked immunosorbent assay. RESULTS:Glycated albumin inhibited the proliferation rate of HUVECs in a time-dependent manner(P

BACKGROUND:Among many transplanted cells,adult autologous bone barrow-derived mononuclear cells have beenused in clinical practice because they are easy to be obtained,without immunological rejection and ethical disputationand other advantages.How to distinguish donor cells from receptors and observe the survival of donor cells following stem cell transplantation still trouble people.OBJECTIVE: superparamagnetic iron oxide (SPIO)particles-labeled bone marrow-derived mononuclear cells from minipigs were used to observe the feasibility of in vivo tracking with magnetic resonance imaging(MRI).DESIGN:A controlled observation experiment.SETTING:Institute of Cardiovascular Disease,Zhongda Hospital Affiliated to Southeast University.MATERIALS:This experiment was carried out in the Institute of Cardiovascular Disease,Zhongda Hospital Affiliated to Southeast University between April 2006 and August 2006.Healthy Chinese minipigs,aged 3 to 4 months,weighing from 20 to 30 kg,were provided by the Experimental Animal Center of Southeast University[SYXK(Su)2002-0012].METHODS: Autologous bone marrow-derived mononuclear cells of minipigs were isolated and cultured. Bone marrow-derived mononuclear cells in the suspension were traced with SPIO particles.Ferrum in the cells were shown by Prussian blue staining, and cell viability was evaluated by trypan blue exclusion method. Eleven minipigs used for preparation of model of myocardial infarction were divided into experimental group(n=9)and control group(n=2).By means of percutaneous left or right cervical artery or femoral artery puncturation, 1.5 to 2.0 mm balloon was used to occlude 1/3 left anterior descending branch,304 to 405 kPa,60 minutes later,ischemic preconditioning was conducted 3 tO 4 times before operation. When pig models of myocardial infarction were successful that was proved by surface electrocardiogram,bone marrow-derived mononuclear cells were percutaneously injected into coronary artery.Coronary arteriography was performed through femoral artery acupuncture at 24 hours after establishing infarction models.Suspension of bone marrow-derived mononuclear cells was perfused into coronary artery with OTW catheter.Then,the injector and OTW catheter for containing cells were rinsed with normal saline containing heparin and infused with the residual cells within 10 minutes.Non-labeled cells were perfused in 2 minipigs of control group by the same method.Postoperatively, bone marrow-derived mononuclear cells were traced by magnetic resonance and compared with Prussian blue-stained myocardial tissue sections.RESULTS: Seven minipigs of experimental group and one minipig of control group were Involved in the final analysis.One of each group was used for preparation of model of myocardial Infarction.One minipig of experimental group died from anesthetic accident before magnetic resonance.①Bone marrow-derived mononuclear cells all were nearly labeled by SPIO particles. Bone marrow-derived mononuclear cells could further proliferate in culture medium containing Fe2O3-PLL without obvious changes of cellular shape. ②T2+WI showed that 5 of 8 models of myocardial infarction presented fuzzy low-echo signal region in peripheral myocardial infarction after transplantation of labeled cells and the low-echo signal disappeared 4 weeks Iater. Ex vivo T2+WI sequence showed there was a dot-distributed low-echo signal region in the peripheral infarction region.③It was found in histological examination that 5 models(cell number over 106) had Prussian blue-positive cells,which distributed the same as those in magnetic resonance signal reducing region.CONCLUSION:SPIO particles-labeled bone marrow-derived mononuclear cells are safe and effective;T2+ WI is sensitive to tracing SPIO particles-labeled bone marrow-derived mononuclear cells;Magnetic resonance can in vivo trace SPIO particles-labeled stem cells transplanted through coronary artery,magnetic resonance signal change is related with the number of stem cells and division growth.

Objective To investigate the hemodynamic changes in a tortuous coronary to elucidate the effects of tortuosity on coronary perfusion and wall shear stress (WSS). Methods A single tortuous and non-tortuous patient-specific left anterior descending (LAD) coronary artery cases were selected. Two LAD models with and without coronary tortuosity were reconstructed in Mimics software and then transferred to the ANSYS Fluent software for performing computational fluid dynamics (CFD) simulation. The hemodynamic characteristics of both the LAD models were compared. Results The vessel WSS of the tortuous coronary artery clearly decreased in the bend section where the maximum curvature was larger than 1 mm-1.Such a scenario could led to an inadequate blood supply in the downstream vessels. A low WSS (0-26 Pa) acted on the outer wall of the bend, whereas the inner wall of the bend had a high WSS (>100 Pa). The mean WSS of the non-tortuous and tortuous models was 10.79 Pa and 36.12 Pa, respectively. The overall WSS of the tortuous model was larger compared with that of the non-tortuous model. Conclusions Coronary tortuosity increased the overall WSS, which could delay the progress of coronary atherosclerosis.