Single-Cell Expression Profiling Reveals a Dynamic State of Cardiac Precursor Cells in the Early Mouse Embryo

In the early vertebrate embryo, cardiac progenitor/precursor cells (CPs) give rise to cardiac structures. Better understanding their biological character is critical to understand the heart development and to apply CPs for the clinical arena. However, our knowledge remains incomplete. With the use of single-cell expression profiling, we have now revealed rapid and dynamic changes in gene expression profiles of the embryonic CPs during the early phase after their segregation from the cardiac mesoderm. Progressively, the nascent mesodermal gene Mesp1 terminated, and Nkx2-5+/Tbx5+ population rapidly replaced the Tbx5low+ population as the expression of the cardiac genes Tbx5 and Nkx2-5 increased. At the Early Headfold stage, Tbx5-expressing CPs gradually showed a unique molecular signature with signs of cardiomyocyte differentiation. Lineage-tracing revealed a developmentally distinct characteristic of this population. They underwent progressive differentiation only towards the cardiomyocyte lineage corresponding to the first heart field rather than being maintained as a progenitor pool. More importantly, Tbx5 likely plays an important role in a transcriptional network to regulate the distinct character of the FHF via a positive feedback loop to activate the robust expression of Tbx5 in CPs. These data expands our knowledge on the behavior of CPs during the early phase of cardiac development, subsequently providing a platform for further study

Effect of rainfall intensity on infiltration into partly saturated slopes

This paper describes the development of a model to analyse the rate of infiltration and run-off experienced by a partly saturated soil slope during rainfall. The paper first reviews some of the most popular infiltration models used in geotechnical analysis, and highlights some of the problems associated with their application. One particular model, the Horton Equation is extended to include rainfall intensity directly in its formulation. The new model is shown to predict infiltration responses, which agree with field measurements. In the final section the influence of the rainfall intensity and pattern of rainfall (variation of rainfall intensity) on the infiltration response of a soil is investigated using the new model.Other funderIarnród Éirean

'En bloc' dissection of epimacular membranes using aspiration delamination

'En bloc' dissection is a technique in which epiretinal membranes (ERM) are separated from the retina as a single lamina with a 20-gauge blunt flute needle. We used this technique to remove epimacular membranes of various aetiologies in a consecutive series of 25 eyes, with a minimum follow-up of 5 months (mean 10.4 months). Small residual epicentres of ERM away from the fovea remained in 7 (29.1%) eyes only; 3 were inside and 4 outside the temporal vascular arcades. Postoperatively 64% (16/25) of patients achieved a final visual acuity of 6/12 or better and 76% (19/25) achieved a final visual acuity of 6/18 or better. Progressive lens opacities were the most important postoperative complication in phakic eyes that significantly affected the visual results. This technique successfully removed epimacular membranes over a wide area, without the need to find a starting edge or the use of sharp instruments near the retina. Diaphanous ERMs with ill-defined borders and tenaciously adherent membranes could be removed with minimal trauma to the underlying retina. Histopathological and immunohistochemical examination of 10 ERMs demonstrated the absence of internal limiting lamina in 6 (60%).link_to_subscribed_fulltex