131 research outputs found
A Mentoring Guide for Female Faculty in Engineering
One widely accepted method for increasing the chances of success of female engineering and science students and faculty alike is to provide access to female role models and mentors. In this article we offer to new female faculty, and to those who would mentor them, an annotated list of text and electronic resources that address most of the most important challenges facing new female faculty in science and engineering
Inhibition of major integrin αVβ3 reduces Staphylococcus aureus attachment to sheared human endothelial cells.
BACKGROUND: Vascular endothelial dysfunction with associated oedema and organ failure is one of the hallmarks of sepsis. While a large number of microorganisms can cause sepsis, Staphylococcus aureus is one of the primary etiological agents. Currently there are no approved specific treatments for sepsis and therefore the initial management bundle focuses on cardiorespiratory resuscitation and mitigation against the immediate threat of uncontrolled infection. The continuous emergence of antibiotic resistant strains of bacteria urges the development of new therapeutic approaches for this disease.
OBJECTIVE: The objective of this study was to identify the molecular mechanisms leading to endothelial dysfunction as a result of Staphylococcus aureus binding.
METHODS: Stahpylococcus aureus Newman and clumping factor A-deficient binding to endothelium were measured in vitro and in the mesenteric circulation of C57Bl/6 mice. The effect of the αVβ3 blocker, cilengitide, on bacterial binding, endothelial VE-cadherin expression, apoptosis, proliferation and permeability were assessed.
RESULTS: Here we show that the major Staphylococcus aureus cell wall protein clumping factor A binds to endothelial cell integrin αVβ3 in the presence of fibrinogen. This interaction results in disturbances in barrier function mediated by VE-cadherin in endothelial cell monolayers and ultimately cell death by apoptosis. Using a low concentration of cilengitide, ClfA binding to αVβ3 was significantly inhibited both in vitro and in vivo. Moreover, preventing Staphylococcus aureus from attaching to αVβ3 resulted in a significant reduction in endothelial dysfunction following infection.
CONCLUSION: Inhibition of Staphylococcus aureus ClfA binding to endothelial cell αVβ3 using cilengitide prevents endothelial dysfunction. This article is protected by copyright. All rights reserved
Helicobacter pylori-induced inhibition of vascular endothelial cell functions: a role for VacA-dependent nitric oxide reduction
Epidemiological and clinical studies provide compelling support for a causal relationship between Helicobacter pylori infection and endothelial dysfunction, leading to vascular diseases. However, clear biochemical evidence for this association is limited. In the present study, we have conducted a comprehensive investigation of endothelial injury in bovine aortic endothelial cells (BAECs) induced by H. pylori-conditioned medium (HPCM) prepared from H. pylori 60190 [vacuolating cytotoxin A (Vac(+))]. BAECs were treated with either unconditioned media, HPCM (0-25% vol/vol), or Escherichia coli-conditioned media for 24 h, and cell functions were monitored. Vac(+) HPCM significantly decreased BAEC proliferation, tube formation, and migration (by up to 44%, 65%, and 28%, respectively). Posttreatment, we also observed sporadic zonnula occludens-1 immunolocalization along the cell-cell border, and increased BAEC permeability to FD40 Dextran, indicating barrier reduction. These effects were blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid (VacA inhibitor) and were not observed with conditioned media prepared from either VacA-deleted H. pylori or E. coli. The cellular mechanism mediating these events was also considered. Vac(+) HPCM (but not Vac(-)) reduced nitric oxide (NO) by \u3e50%, whereas S-nitroso-N-acetylpenicillamine, an NO donor, recovered all Vac(+) HPCM-dependent effects on cell functions. We further demonstrated that laminar shear stress, an endothelial NO synthase/NO stimulus in vivo, could also recover the Vac(+) HPCM-induced decreases in BAEC functions. This study shows, for the first time, a significant proatherogenic effect of H. pylori-secreted factors on a range of vascular endothelial dysfunction markers. Specifically, the VacA-dependent reduction in endothelial NO is indicated in these events. The atheroprotective impact of laminar shear stress in this context is also evident
Platelets: From Formation to Function
Platelets are small, anucleate cells that travel as resting discoid fragments in the circulation. Their average circulating life span is 8–9 days, and their formation is an elegant and finely orchestrated series of cellular processes known as megakaryocytopoiesis and thrombopoiesis. This involves the commitment of haematopoietic stem cells, proliferation, terminal differentiation of megakaryocytic progenitors and maturation of megakaryocytes to produce functional platelets. This complex process occurs in specialised endosteal and vascular niches in the bone marrow where megakaryocytes form proplatelet projections, releasing platelets into the circulation. Upon contact with an injured blood vessel, they prevent blood loss through processes of adhesion, activation and aggregation. Platelets play a central role in cardiovascular disease (CVD), both in the development of atherosclerosis and as the cellular mediator in the development of thrombosis. Platelets have diverse roles not limited to thrombosis/haemostasis, also being involved in many vascular inflammatory conditions. Depending on the physiological context, platelet functions may be protective or contribute to adverse thrombotic and inflammatory outcomes. In this chapter, we will discuss platelets in context of their formation and function. Because of their multifaceted role in maintaining physiological homeostasis, current and development of platelet function testing platforms will be discussed
Regulation of IL-1β-induced NFκB by hydroxylases links key hypoxic and inflammatory signaling pathways
Hypoxia is a prominent feature of chronically inflamed tissues. Oxygen-sensing hydroxylases control transcriptional adaptation to hypoxia through the regulation of hypoxia-inducible factor (HIF) and nuclear factor ?B (NF-?B), both of which can regulate the inflammatory response. Furthermore, pharmacologic hydroxylase inhibitors reduce inflammation in multiple animal models. However, the underlying mechanism(s) linking hydroxylase activity to inflammatory signaling remains unclear. IL-1ß, a major proinflammatory cytokine that regulates NF-?B, is associated with multiple inflammatory pathologies. We demonstrate that a combination of prolyl hydroxylase 1 and factor inhibiting HIF hydroxylase isoforms regulates IL-1ß-induced NF-?B at the level of (or downstream of) the tumor necrosis factor receptor-associated factor 6 complex. Multiple proteins of the distal IL-1ß-signaling pathway are subject to hydroxylation and form complexes with either prolyl hydroxylase 1 or factor inhibiting HIF. Thus, we hypothesize that hydroxylases regulate IL-1ß signaling and subsequent inflammatory gene expression. Furthermore, hydroxylase inhibition represents a unique approach to the inhibition of IL-1ß-dependent inflammatory signaling
ActEarly: a City Collaboratory approach to early promotion of good health and wellbeing.
Economic, physical, built, cultural, learning, social and service environments have a profound effect on lifelong health. However, policy thinking about health research is dominated by the 'biomedical model' which promotes medicalisation and an emphasis on diagnosis and treatment at the expense of prevention. Prevention research has tended to focus on 'downstream' interventions that rely on individual behaviour change, frequently increasing inequalities. Preventive strategies often focus on isolated leverage points and are scattered across different settings. This paper describes a major new prevention research programme that aims to create City Collaboratory testbeds to support the identification, implementation and evaluation of upstream interventions within a whole system city setting. Prevention of physical and mental ill-health will come from the cumulative effect of multiple system-wide interventions. Rather than scatter these interventions across many settings and evaluate single outcomes, we will test their collective impact across multiple outcomes with the goal of achieving a tipping point for better health. Our focus is on early life (ActEarly) in recognition of childhood and adolescence being such critical periods for influencing lifelong health and wellbeing
Room temperature coherent control of coupled single spins in solid
Coherent coupling between single quantum objects is at the heart of modern
quantum physics. When coupling is strong enough to prevail over decoherence, it
can be used for the engineering of correlated quantum states. Especially for
solid-state systems, control of quantum correlations has attracted widespread
attention because of applications in quantum computing. Such coherent coupling
has been demonstrated in a variety of systems at low temperature1, 2. Of all
quantum systems, spins are potentially the most important, because they offer
very long phase memories, sometimes even at room temperature. Although precise
control of spins is well established in conventional magnetic resonance3, 4,
existing techniques usually do not allow the readout of single spins because of
limited sensitivity. In this paper, we explore dipolar magnetic coupling
between two single defects in diamond (nitrogen-vacancy and nitrogen) using
optical readout of the single nitrogen-vacancy spin states. Long phase memory
combined with a defect separation of a few lattice spacings allow us to explore
the strong magnetic coupling regime. As the two-defect system was well-isolated
from other defects, the long phase memory times of the single spins was not
diminished, despite the fact that dipolar interactions are usually seen as
undesirable sources of decoherence. A coherent superposition of spin pair
quantum states was achieved. The dipolar coupling was used to transfer spin
polarisation from a nitrogen-vacancy centre spin to a nitrogen spin, with
optical pumping of a nitrogen-vacancy centre leading to efficient
initialisation. At the level anticrossing efficient nuclear spin polarisation
was achieved. Our results demonstrate an important step towards controlled spin
coupling and multi-particle entanglement in the solid state
Environmental and socio-demographic associates of children's active transport to school: a cross-sectional investigation from the URBAN Study
BACKGROUND: Active transport (e.g., walking, cycling) to school (ATS) can contribute to children's physical activity and health. The built environment is acknowledged as an important factor in understanding children's ATS, alongside parental factors and seasonality. Inconsistencies in methodological approaches exist, and a clear understanding of factors related to ATS remains equivocal. The purpose of this study was to gain a better understanding of associates of children's ATS, by considering the effects of daily weather patterns and neighbourhood walk ability and neighbourhood preferences (i.e., for living in a high or low walkable neighbourhood) on this behaviour.
METHODS: Data were drawn from the Understanding Relationships between Activity and Neighbourhoods study, a cross-sectional study of physical activity and the built environment in adults and children in four New Zealand cities. Parents of participating children completed an interview and daily trip diary that assessed their child's mode of travel to school, household and individual demographic information, and parental neighbourhood preference. Daily weather data were downloaded from New Zealand's national climate database. Geographic information systems-derived variables were calculated for distance to school and neighbourhood walkability. Bivariate analyses were conducted with ATS and potential associates; factors related to ATS at p less than 0.20 were considered simultaneously in generalized estimation equation models, and backwards elimination of non-significant factors was conducted; city was treated as a fixed effect in all models.
RESULTS: A total of 217 children aged 6.5-15 years participated in this study. Female sex, age, city, household income, limited/no car access, residing in zone of school, shorter distance to school, neighbourhood self selection, rainfall, and sunlight hours were simultaneously considered in multivariate generalised estimation equation modelling (all p less than 0.20 in bivariate analyses). After elimination of non-significant factors, age (p = 0.005), shorter distance to school (p less than 0.001), city (p = 0.03), and neighbourhood self selection (p = 0.04) remained significantly associated with ATS in the multivariate analysis.
CONCLUSION: Distance to school is the prevailing environmental influencing factor on children's ATS. This study, in conjunction with previous research, suggests that school siting is likely an important associate of children's ATS
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