Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models

Angiogenesis is fundamental to many physiological processes, and associated with various pathologies, including atherosclerosis and malignant disease. Increasing evidence suggests a role for the cytoprotective enzyme heme oxygenase-1 (HO-1) and its products in angiogenesis. However, the mechanisms through which HO-1 exerts its effects remain elusive. This study aims to identify signalling pathways and novel HO-1 downstream targets regulating angiogenesis. I show that inhibition of HO-1 with synthetic antagonist (ZnPP) or specific siRNA alters the angiogenic process at various levels. HO-1 inhibition significantly reduced vascular endothelial growth factor A (VEGF)-mediated human endothelial cell (EC) proliferation and inhibited capillary-like formation on 2D-Matrigel. Further, I demonstrate that VEGF-induced EC cell cycle progression is inhibited by HO-1 siRNA; an observation associated with decreased expression of cell cycle regulators cyclin A1 and cyclin E1. In contrast, HO-1-deficient cells were still protected from apoptosis by VEGF, most likely through induction of anti-apoptotic genes Bcl-2 and A1. Interestingly, HO-1 depletion negatively affected directional migration of EC towards a VEGF gradient; a phenotype reversed by HO-1 over-expression using an adenoviral vector. Moreover, migrating HO-1-deficient cells showed decreased cyclin A1 protein accompanied by decreased cyclin-dependent kinase 2 activity. Importantly, a combined proteomics and microarray approach has identified downstream targets of HO-1 and their potential roles in HO-1-driven angiogenesis have been investigated. For instance, HO-1 depletion results in impaired assembly of the intermediate filament vimentin. HO-1-deficient cells show reduced activity of the calcium-dependent protease calpain in response to VEGF; this observation was accompanied by a decrease in vimentin cleavage. The differences in vimentin cleavage and filament assembly may in turn account for the impaired angiogenic phenotype of HO-1-deficient cells. Identification of HO-1 downstream target genes may reveal potential therapeutic approaches for enhancing angiogenesis at sites of ischaemia or wound healing, or alternatively inhibiting angiogenesis associated with atherosclerosis or tumourogenesis

Hydrographical and biogeochemical characterization of the Beibu Gulf, South China Sea

The Beibu Gulf is a marginal sea of the South China Sea (SCS) and plays an important role for material fluxes to the SCS northwestern regions. Using hydrographical profiles, water and sediment samples, different zones were distinguished for the sampling period in autumn 2009, influenced by tidal mixing, riverine input and water mass transport from the SCS. While wind forcing affects the water column structure, hence driving primary production with an increasing effect of strong wind events (typhoons), tidal forcing influences sedimentation patterns and geochemical properties in the Beibu Gulf

The photonic wheel: demonstration of a state of light with purely transverse angular momentum

The concept of angular momentum is ubiquitous to many areas of physics. In classical mechanics, a system may possess an angular momentum which can be either transverse (e.g., in a spinning wheel) or longitudinal (e.g., for a fluidic vortex) to the direction of motion. Photons, however, are well-known to exhibit intrinsic angular momentum which is longitudinal only: the spin angular momentum defining the beam polarization and the orbital angular momentum associated with a spiraling phase front. Here we show that it is possible to generate a novel state of light that contains purely transverse angular momentum, the analogue of a spinning mechanical wheel. We use an optical nano-probing technique to experimentally demonstrate its occurrence in our setup. Such a state of light can provide additional rotational degree of freedom in optical tweezers and optical manipulation.Comment: 15 pages including SO

Geometric spin Hall effect of light in tightly focused polarization tailored light beams

Recently, it was shown that a non-zero transverse angular momentum manifests itself in a polarization dependent intensity shift of the barycenter of a paraxial light beam [A. Aiello et al., Phys. Rev. Lett. 103, 100401 (2009)]. The underlying effect is phenomenologically similar to the spin Hall effect of light, but does not depend on the specific light-matter interaction and can be interpreted as a purely geometric effect. Thus, it was named the geometric spin Hall effect of light. Here, we experimentally investigate the appearance of this effect in tightly focused vector-beams. We use an experimental nano-probing technique in combination with a reconstruction algorithm to verify the relative shifts of the components of the electric energy density in the focal plane, which are linked to the intensity shift. By that, we experimentally demonstrate the geometric spin Hall effect of light in a focused light beam.Comment: 8 pages, 5 figure

Greener households? The effectiveness of smart meters in reducing energy consumption levels in the DACH region

With public opinion shifting to a believe in climate change in the early 2000s the interest in energy efficiency has been increasing. EU Directives set the goal of deploying smart meters if cost efficient for providing more detailed energy consumption. The main goal is to better inform consumers and to give individual households the power to change possibly energy wasting behaviours. This paper evaluates through a literature review the effectiveness of intelligent electricity metering systems with a focus on the DACH region, the provision of different types of feedback and its persistence. It can be concluded that energy feedback enabled by smart meters can lead to savings in the range of 0% to 4.5% in this region. If feedback is provided continuously savings persist. However, several aspects have to be considered to ensure effectiveness of smart meter deployment

Knowledge and Perceptions of Electronic Cigarette Use among Pregnant Women

poster abstractThe association between maternal tobacco smoke exposure and restricted fetal growth has been well studied. However, the safety of electronic cigarettes (e-cigarettes) is quite controversial among pregnant women and the public. Research on the health effects of e-cigarette use during pregnancy is limited, particularly because of the health risks and ethical considerations. However, there is concern about the effects of the nicotine on fetal health from e-cigarettes. Some women’s beliefs about e-cigarettes are influenced by information that e-cigarettes may be beneficial as a way to decrease the number of tobacco cigarettes smoked. We conducted a systematic review of the literature to explore the knowledge and perceptions of e-cigarette use among pregnant women. Using pre-designated inclusion and exclusion criteria, relevant articles were located and reviewed searching PubMed, EMBASE, EBSCOhost, CINAHL Complete, and the reference lists of related articles. Full text, English language, peer-reviewed articles relevant to pregnant women’s knowledge and perceptions of e-cigarettes were reviewed. Of the thirty studies, six met the inclusion criteria. The following findings were common among the studies reviewed: 1) study participants had inaccurate information regarding the amount of nicotine in ecigarettes and the effects on the fetus; 2) e-cigarettes were perceived as safe alternatives and could be used for smoking cessation; 3) using e-cigarettes caused less negative side effects than traditional cigarettes; and 4) information obtained from the media about e-cigarettes was confusing for pregnant women. The findings support the need for healthcare providers to assess e-cigarette use among pregnant women and provide accurate information regarding e-cigarettes and the potential impact of use during pregnancy