Early diastolic mitral annular velocity at the interventricular septal annulus correctly reflects left ventricular longitudinal myocardial relaxation

Aims: Early diastolic mitral annular velocity (e') obtained by tissue Doppler imaging (TDI) is widely used to evaluate left ventricular (LV) diastolic function based on the assumption that it reflects myocardial relaxation in the long-axis direction. In this study, we aimed to determine whether or not e' truly reflects early diastolic longitudinal myocardial relaxation, and which is the most useful for evaluating LV diastolic function among e' measured at the interventricular-septal annulus (IS-e'), that measured at the lateral annulus (LW-e') or their mean value (M-e'). Methods and results: IS-e', LW-e', and M-e' were measured using colour TDI in 15 patients with hypertrophic cardiomyopathy, 13 patients with hypertension and 19 control subjects. Using two-dimensional speckle tracking imaging, early diastolic myocardial strain rates (SR_[E]) were measured for the IS (IS-SR_[E]), LW(LW-SR_[E]) and entire LV myocardium (G-SR_[E]). IS-e' was excellently correlated with IS-SR_[E] (r = 0.90, P < 0.001); the correlation was better than that between LW-e' and LW-SR_[E] (r = 0.75, P < 0.001). IS-e' and M-e' were well correlated with G-SR_[E] (r = 0.88, P < 0.001 and r = 0.86, P < 0.001, respectively) and with LV early diastolic flow propagation velocity (r = 0.77, P < 0.001 and r = 0.78, P < 0.001, respectively). The correlations of LW-e' to G-SR_[E] (r = 0.80, P < 0.001) and flow propagation velocity (r = 0.75, P < 0.001) did not reach this level. Conclusion: IS-e' well reflected LV longitudinal myocardial relaxation and LV diastolic function, and was found to be more useful in evaluating LV diastolic function than LW-e'

Effect of Mechanical Instability of Polymer Scaffolds on Cell Adhesion

The adhesion of fibroblast on polymer bilayers composed of a glassy polystyrene (PS) prepared on top of a rubbery polyisoprene (PI) was studied. Since the top PS layer is not build on a glassy, or firm, foundation, the system becomes mechanically unstable with decreasing thickness of the PS layer. When the PS film was thinner than 25 nm, the number of cells adhered to the surface decreased and the cells could not spread well. On a parallel experiment, the same cell adhesion behavior was observed on plasma-treated PS/PI bilayer films, where in this case, the surface was more hydrophilic than that of the intact films. In addition, the fluorescence microscopic observations revealed that the formation of F-actin filaments in fibroblasts attached to the thicker PS/PI bilayer films was greater than those using the thinner PS/PI bilayer films. On the other hand, the thickness dependence of the cell adhesion behavior was not observed for the PS monolayer films. Taking into account that the amount of adsorbed protein molecules evaluated by a quartz crystal microbalance method was independent of the PS layer thickness of the bilayer films, our results indicate that cells, unlike protein molecules, could sense a mechanical instability of the scaffold