ABSTRACT
Objective To evaluate the impact of chest blast injury on left ventricular function and myocardial strain with speckle tracking imaging (STI).Methods Fifty healthy New Zealand rabbits were randomly divided into 4 groups.Five rabbits without blast injury were used as a normal group,and the other rabbits were placed in specific semi-enclosed blasting environment in accordance with the different distance of the explosion.With instantaneous detonators,slight,medium and heavy chest blast injury animal models were produced and labeled as A,B,and C group (each n=15),respectively.The left ventricular function was measured with conventional echocardiography and STI.The longitudinal strain (LS) of the left ventricle was measured with two-dimensional strain analysis software and statistically analyzed.Results There was no significant difference of ejection fraction (EF) and fractional shortening (FS) in the left ventricle after chest blast injury between group A and normal group (all P＞0.05),while LS of anterior wall,anterior septum wall and lateral wall of group A significantly decreased compared with those of normal group (all P＜0.05).In group B and C,the left ventricular EF,FS and LS of each segment were lower than those of normal group (all P＜0.05).In group C,the left ventricular EF,FS and LS of each segment were lower than those in group A (all P＜0.05).There was no significant difference of EF and FS between group B and group C.In group C,LS of anterior wall and lateral wall of basal segment and middle segment were lower than those of group B (all P＜0.05).Conclusion STI can reflect functional changes of left ventricle in each segment earlier and more sensitively after chest blast injury.
ABSTRACT
Objective To investigate the cell compatibility of polystyrene(PS) plate chemically modified with RGD peptides.Methods PS surfaces were carboxylated by permanganate oxidation in diluted sulfuric acid,and carboxyls were activated with water-soluble carbodiimide to graft with gelatin,collagen and RGD peptides.IR,X-ray photo-electronic spectroscopy (XPS) and dynamic contact angle were used to characterize the surface modification of PS surface.Results XPS results confirmed the existence of nitrogen element from protein molecules and the covalently binding of proteins to PS surfaces.Dynamic contact angle measurement indicated hydrophilicity of PS surfaces was improved obviously after grafting modification.The cell culture results showed that the cell adhesion and proliferation was better on modified surfaces than the initial.Conclusion The cell compatibility of PS surface was great improved after modification with RGD peptides,which would provide a potential strategy to improve the culture of purified endothelial progenitor cells isolated by immunomagnetic beads.