Altered pericyte-endothelial relations in the rat retina during aging: Implications for vessel stability

Mural cells (smooth muscle cells and pericytes) regulate blood flow and contribute to vessel stability. We examined whether mural cell changes accompany age-related alterations in the microvasculature of the central nervous system. The retinas of young adult and aged Wistar rats were subjected to immunohistofluorescence analysis of a-smooth muscle actin (SMA), caldesmon, calponin, desmin, and NG2 to identify mural cells. The vasculature was visualized by lectin histochemistry or perfusion of horse-radish peroxidase, and vessel walls were examined by electron microscopy. The early stage of aging was characterized by changes in peripheral retinal capillaries, including vessel broadening, thickening of the basement membrane, an altered length and orientation of desmin filaments in pericytes, a more widespread SMA distribution and changes in a subset of pre-arteriolar sphincters. In the later stages of aging, loss of capillary patency, aneurysms, distorted vessels, and foci of angiogenesis were apparent, especially in the peripheral deep vascular plexus. The capillary changes are consistent with impaired vascular autoregulation and may result in reduced pericyte-endothelial cell contact, destabilizing the capillaries and rendering them susceptible to angiogenic stimuli and endothelial cell loss as well as impairing the exchange of metabolites required for optimal neuronal function. This metabolic uncoupling leads to reactivation of

Modulating mythology in a post-traumatic era: Murals and re-imaging in Northern Ireland.

Arguably the most ancient of the social media, wall paintings have been a persistent vehicle of cultural meaning management. The dynamics of myth markets are reflected in the sectarian murals of Northern Ireland. In this paper, we draw from consumer research literature on mythology and street art to explore the continuous revision of these wallscapes that seeks to address the enduring contradictions of civic ideology in contested political space. In particular, we focus on the use of classical, historical and pop-cultural mythologies to transform private space into public place. We examine the decommissioning of murals occurring in the wake of the Peace Accords, and speculate on the implications of the creation of a shared mythology for the future of mural painting and the state.