Mesenchymal stem cells overexpressing MiR-126 enhance ischemic angiogenesis via the AKT/ERK-related pathway

Background: This study was designed to examine whether transplantation of mesenchymal stem cells (MSCs) overexpressing miR-126 enhances angiogenesis in the infarcted myocardium of mice. Methods: MSCs were harvested from mice using density gradient centrifugation and adherent culture. MSCs were transfected with lentiviral vectors carrying mature miR-126. Mice models of myocardial infarction were established by ligation of coronary artery. The ligated animals were randomly divided into three groups (15 in each) and after two weeks, were intramyocardially injected at the heart infarct zone with miR-126-transfected MSCs (the miR-126-MSCs group), MSCs (the MSCs group), or medium (the PBS group). Six weeks later, histological study and echocardiographic assessment were performed. Results: Capillary density of the infarcted region was significantly improved in the miR-126- MSCs group compared to the MSC group and the PBS group (both p < 0.01). Western blot showed that ERK1, pERK1, AKT and pAKT gene were dramatically enhanced in the miR-126-MSC group compared to the MSC group and the PBS group (both p < 0.05). Echocardiography showed MiR-126 led to a sustained improvement in cardiac function for at least six weeks at the injected area, as assessed by left ventricular ejection fraction and fraction of shortening. Conclusions: Transplantation of MSCs transfected with miR-126 can improve angiogenesis and cardiac function in the infarcted area of the hearts of mice, which may be due to stimulation of the AKT/ERK-related pathway. (Cardiol J 2011; 18, 6: 675&#8211;681

F-wave heavy-light meson spectroscopy in QCD sum rules and heavy quark effective theory

We study the F-wave c_bar s heavy meson doublets (2+,3+) and (3+,4+). They have large orbital excitations L=3, and may be good challenges (tests) for theoretical studies. To study them we use the method of QCD sum rule in the framework of heavy quark effective theory. Their masses are predicted to be m_{(2+,3+)} = (3.45 \pm 0.25, 3.50 \pm 0.26) GeV and m_{(3+,4+)} = (3.20 \pm 0.22, 3.26 \pm 0.23) GeV, with mass splittings Delta m_{(2+,3+)} = m_{3+} - m_{2+} = 0.046 \pm 0.030 GeV and Delta m_{(3+,4+)} = 0.053 \pm 0.044 GeV, respectively. We note that this is a pioneering work and these results are provisional.Comment: 10 pages, 8 figures, 3 tables, accepted by PR

New Confidence Intervals for the Difference between Two Sensitivities at a Fixed Level of Specificity

For two continuous-scale diagnostic tests, it is of interest to compare their sensitivities at a predetermined level of specificity. In this paper we propose three new intervals for the difference between two sensitivities at a fixed level of specificity. These intervals are easy to compute. We also conduct simulation studies to compare the relative performance of the new intervals with the existing normal approximation based interval proposed by Wieand et al (1989). Our simulation results show that the newly proposed intervals perform better than the existing normal approximation based interval in terms of coverage accuracy and interval length