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MicroRNAs (miRNAs) are natural, single-stranded, small RNA molecules which subtly control gene expression. Several studies indicate that specific miRNAs can regulate heart function both in development and disease. Despite prevention programs and new therapeutic agents, cardiovascular disease remains the main cause of death in developed countries. The elevated number of heart failure episodes is mostly due to myocardial infarction (MI). An increasing number of studies have been carried out reporting changes in miRNAs gene expression and exploring their role in MI and heart failure. In this review, we furnish a critical analysis of where the frontier of knowledge has arrived in the fields of basic and translational research on miRNAs in cardiac ischemia. We first summarize the basal information on miRNA biology and regulation, especially concentrating on the feedback loops which control cardiac-enriched miRNAs. A focus on the role of miRNAs in the pathogenesis of myocardial ischemia and in the attenuation of injury is presented. Particular attention is given to cardiomyocyte death (apoptosis and necrosis), fibrosis, neovascularization, and heart failure. Then, we address the potential of miR-diagnosis (miRNAs as disease biomarkers) and miR-drugs (miRNAs as therapeutic targets) for cardiac ischemia and heart failure. Finally, we evaluate the use of miRNAs in the emerging field of regenerative medicine. [ABSTRACT FROM AUTHOR]

The coupling of two macroscopic quantum states through a tunnel barrier gives rise to Josephson phenomena such as Rabi oscillations, the a.c. and d.c. effects, or macroscopic self-trapping, depending on whether tunnelling or interactions dominate. Nonlinear Josephson physics was first observed in superfluid helium and atomic condensates, but it has remained inaccessible in photonic systems because it requires large photon-photon interactions. Here we report on the observation of nonlinear Josephson oscillations of two coupled polariton condensates confined in a photonic molecule formed by two overlapping micropillars etched in a semiconductor microcavity. At low densities we observe coherent oscillations of particles tunnelling between the two sites. At high densities, interactions quench the transfer of particles, inducing the macroscopic self-trapping of polaritons in one of the micropillars. The finite lifetime results in a dynamical transition from self-trapping to oscillations with π phase. Our results open the way to the experimental study of highly nonlinear regimes in photonic systems, such as chaos or symmetry-breaking bifurcations. [ABSTRACT FROM AUTHOR]

Although photons in vacuum are massless particles that do not appreciably interact with each other, significant interactions appear in suitable nonlinear media, leading to hydrodynamic behaviours typical of quantum fluids. Here, we show the generation and manipulation of vortex-antivortex pairs in a coherent gas of strongly dressed photons (polaritons) flowing against an artificial potential barrier created and controlled by a light beam in a semiconductor microcavity. The optical control of the polariton flow allows us to reveal new quantum hydrodynamical phenomenologies such as the formation of vortex pairs upstream from the optical barrier, a case of ultrashort time excitation of the quantum flow, and the generation of vortices with counterflow trajectories. Additionally, we demonstrate how to permanently trap and store quantum vortices hydrodynamically generated in the wake of a defect. These observations are supported by time-dependent simulations based on the non-equilibrium Gross-Pitaevskii equation. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) is a leading cause of hospitalization worldwide. A recently developed strategy to improve the management of MI is based on the use of growth factors which are able to enhance the intrinsic capacity of the heart to repair itself or regenerate after damage. Among others, hepatocyte growth factor (HGF) has been proposed as a modulator of cardiac repair of damage due to the pleiotropic effects elicited by Met receptor stimulation. In this review we describe the mechanistic basis for autocrine and paracrine protection of HGF in the injured heart. We also analyse the role of HGF/Met in stem cell maintenance and in stem cell therapies for MI. Finally, we summarize the most significant results on the use of HGF in experimental models of heart injury and discuss the potential of the molecule for treating ischaemic heart disease in humans. [ABSTRACT FROM AUTHOR]

A method of producing freeze-dried Brucella abortus Strain 19 vaccine by using batch cultures on fermentation units is described. Details of the equipment and technique employed, results on microbiological and biological controls are given. [ABSTRACT FROM AUTHOR]