(C) 2010 Elsevier B.V. All rights reserved.”
“The aim of this study was to investigate the activation of JNK1/2 signalling pathway and the respective cellular phenotype of H9c2 cardiac myoblasts during two distinct types of oxidative insult. We examined the dose- and time-dependent activation of JNK1/2 pathway by exogenous H2O2, both under transient and sustained stimulation. At 2 h of either sustained or transient treatment, Cyclosporin A mw maximal phosphorylation of c-Jun was observed, coincidently with the activation of nuclear JNK1/2; under sustained stress, these phosphorylation levels remained elevated above basal

for up to 6 h, whereas under transient stress they declined to basal ones within 4 h of withdrawal. Furthermore, the JNK1/2 selective inhibitor SP600125 abolished the c-jun phosphorylation induced by oxidative stress. Our results using cell viability assays and light microscopy revealed that sustained H2O2 stimulation significantly and time-dependently decreased H9c2 viability, in contrast to

transient stimulation; SP600125 (10 mu M) abolished cell death induced by sustained as well as cell survival induced by transient oxidative stress. Hoechst staining showed an increase in DNA condensation during sustained, but not during transient stimulation. Moreover, from the antioxidants tested, catalase and superoxide dismutase prevented oxidative stress-induced cell death. Flow cytometry studies reconfirmed that sustained oxidative stress induced apoptosis, whereas NU7026 transient resulted in the recovery of cardiac myoblasts within 24 h. We conclude

that in H9c2 myoblasts, sustained activation of JNK1/2 signalling pathway during oxidative stimulation is followed by an apoptotic phenotype, while transient JNK1/2 activation correlates well with cell survival, suggesting a dual role of this signalling pathway in cell fate determination.”
“Left Atrial Stiffness and Atrial Fibrillation. Introduction: An increased left atrial (LA) stiffness reflects the structural remodeling and deterioration of the LA function. This study was designed to estimate LA stiffness by measuring a combination of the strain and LA pressure in patients undergoing pulmonary vein isolation Compound C cell line (PVI) of atrial fibrillation (AF) and to evaluate the influence of the LA stiffness on the cardiac function, serum markers, and recurrence of AF after PVI.\n\nMethods: In 155 consecutive patients with AF, the brain natriuretic peptide (BNP) and aminoterminal procollagen type III propeptide (PIIIP) plasma levels were measured before the PVI. The difference between the minimum and maximum LA systolic pressures was directly measured by a transseptal puncture. The ratio of the difference in the LA pressures to the peak systolic LA strain evaluated by speckle-tracking echocardiography was used as an index of the LA stiffness.