Inhibition of transforming growth factor-β restores endothelial thromboresistance in vein grafts

BackgroundThrombosis is a major cause of the early failure of vein grafts (VGs) implanted during peripheral and coronary arterial bypass surgeries. Endothelial expression of thrombomodulin (TM), a key constituent of the protein C anticoagulant pathway, is markedly suppressed in VGs after implantation and contributes to local thrombus formation. While stretch-induced paracrine release of transforming growth factor-β (TGF-β) is known to negatively regulate TM expression in heart tissue, its role in regulating TM expression in VGs remains unknown.MethodsChanges in relative mRNA expression of major TGF-β isoforms were measured by quantitative polymerase chain reaction (qPCR) in cultured human saphenous vein smooth muscle cells (HSVSMCs) subjected to cyclic stretch. To determine the effects of paracrine release of TGF-β on endothelial TM mRNA expression, human saphenous vein endothelial cells (HSVECs) were co-cultured with stretched HSVSMCs in the presence of 1D11, a pan-neutralizing TGF-β antibody, or 13C4, an isotype-control antibody. Groups of rabbits were then administered 1D11 or 13C4 and underwent interpositional grafting of jugular vein segments into the carotid circulation. The effect of TGF-β inhibition on TM gene expression was measured by qPCR; protein C activating capacity and local thrombus formation were measured by in situ chromogenic substrate assays; and VG remodeling was assessed by digital morphometry.ResultsCyclic stretch induced TGF-β1 expression in HSVSMCs by 1.9 ± 0.2-fold (P < .001) without significant change in the expressions of TGF-β2 and TGF-β3. Paracrine release of TGF-β1 by stretched HSVSMCs inhibited TM expression in stationary HSVECs placed in co-culture by 57 ± 12% (P = .03), an effect that was abolished in the presence of 1D11. Similarly, TGF-β1 was the predominant isoform induced in rabbit VGs 7 days after implantation (3.5 ± 0.4-fold induction; P < .001). TGF-β1 protein expression localized predominantly to the developing neointima and coincided with marked suppression of endothelial TM expression (16% ± 2% of vein controls; P < .03), a reduction in situ activated protein C (APC)-generating capacity (53% ± 9% of vein controls; P = .001) and increased local thrombus formation (3.7 ± 0.8-fold increase over vein controls; P < .01). External stenting of VGs to limit vessel distension significantly reduced TGF-β1 induction and TM downregulation. Systemic administration of 1D11 also effectively prevented TM downregulation, preserved APC-generating capacity, and reduced local thrombus in rabbit VGs without observable effect on neointima formation and other morphometric parameters 6 weeks after implantation.ConclusionTM downregulation in VGs is mediated by paracrine release of TGF-β1 caused by pressure-induced vessel stretch. Systemic administration of an anti-TGF-β antibody effectively prevented TM downregulation and preserved local thromboresistance without negative effect on VG remodeling.Clinical RelevanceVein grafts (VGs) are commonly used conduits for coronary and peripheral arterial bypass surgeries. Thrombosis is a major cause of early VG failure. Trombomodulin (TM), a key component of the anticoagulant protein C pathway, is downregulated early after VG implantation and facilitates local thrombus formation. We found that paracrine release of transforming growth factor-β1 (TGF-β1), caused by pressure-induced stretch, was a potent negative regulator of TM in rabbit VGs. Administration of a neutralizing anti-TGF-β antibody effectively prevented TM downregulation and reduced local thrombus generation without adversely affecting long-term VG remodeling. This may represent a novel strategy to improve patency in patients undergoing arterial bypass procedures

Nuclear variants of bone morphogenetic proteins

<p>Abstract</p> <p>Background</p> <p>Bone morphogenetic proteins (BMPs) contribute to many different aspects of development including mesoderm formation, heart development, neurogenesis, skeletal development, and axis formation. They have previously been recognized only as secreted growth factors, but the present study detected Bmp2, Bmp4, and Gdf5/CDMP1 in the nuclei of cultured cells using immunocytochemistry and immunoblotting of nuclear extracts.</p> <p>Results</p> <p>In all three proteins, a bipartite nuclear localization signal (NLS) was found to overlap the site at which the proproteins are cleaved to release the mature growth factors from the propeptides. Mutational analyses indicated that the nuclear variants of these three proteins are produced by initiating translation from downstream alternative start codons. The resulting proteins lack N-terminal signal peptides and are therefore translated in the cytoplasm rather than the endoplasmic reticulum, thus avoiding proteolytic processing in the secretory pathway. Instead, the uncleaved proteins (designated nBmp2, nBmp4, and nGdf5) containing the intact NLSs are translocated to the nucleus. Immunostaining of endogenous nBmp2 in cultured cells demonstrated that the amount of nBmp2 as well as its nuclear/cytoplasmic distribution differs between cells that are in M-phase versus other phases of the cell cycle.</p> <p>Conclusions</p> <p>The observation that nBmp2 localization varies throughout the cell cycle, as well as the conservation of a nuclear localization mechanism among three different BMP family members, suggests that these novel nuclear variants of BMP family proteins play an important functional role in the cell.</p

Dangerous work: The gendered nature of bullying in the context of higher education

This paper discusses results from a research project which set out to investigate gender differences in the nature and experience of bullying within the higher education sector. Gender differences emerged in the form and perception of bullying as well as in target response. Results also indicate that, irrespective of gender, bullies can capture and subvert organizational structures and procedures (official hierarchies, mentoring systems, probationary reviews) to further their abuse of the target and to conceal aggressive intent. These outcomes are discussed in relation to gendered assumptions behind management practices and in relation to the masculinist ethic that underpins many higher education management initiatives. Overall, results indicate that bullying cannot be divorced from gender and that such behaviour needs to be seen in a gendered context

Quantum Theory and Time Asymmetry

The relation between quantum measurement and thermodynamically irreversible processes is investigated. The reduction of the state vector is fundamentally asymmetric in time and shows an observer-relatedness which may explain the double interpretation of the state vector as a representation of physical states as well as of information about them. The concept of relevance being used in all statistical theories of irreversible thermodynamics is shown to be based on the same observer-relatedness. Quantum theories of irreversible processes implicitly use an objectivized process of state vector reduction. The conditions for the reduction are discussed, and I speculate that the final (subjective) observer system might even be carried by a spacetime point.Comment: Latex version of a paper published in 1979 (with minor revisions), 18 page

The articulation of enkinaesthetic entanglement

In this article I present an argument for the necessary co-articulation of meaning within our felt enkinaesthetic engagement with our world. The argument will be developed through a series of stages, the first of which will be an elaboration of the notion of articulation of and through the body. This will be followed by an examination of enkinaesthetic experiential entanglement and the role it plays in rendering our world meaningful and our actions values-realising. At this stage I will begin to extend Husserl’s notion of intentional transgression to the enkinaesthetic sphere of lived experience, and in support of this claim I will examine the theoretical and practical work of osteopathic manual listening [Gens &amp; Roche 2014] and the ‘felt sense’ in focusing [Gendlin] which makes possible a shift from a somatic articulation to a semantic, and potentially conceptual, one. Throughout, my position will be compatible with Merleau-Ponty’s claim that “Whenever I try to understand myself, the whole fabric of the perceptible world comes too, and with it comes the others who are caught in it.” [Merleau-Ponty 1964a, p.15]

Polymer depletion interaction between two parallel repulsive walls

The depletion interaction between two parallel repulsive walls confining a dilute solution of long and flexible polymer chains is studied by field-theoretic methods. Special attention is paid to self-avoidance between chain monomers relevant for polymers in a good solvent. Our direct approach avoids the mapping of the actual polymer chains on effective hard or soft spheres. We compare our results with recent Monte Carlo simulations [A. Milchev and K. Binder, Eur. Phys. J. B 3, 477 (1998)] and with experimental results for the depletion interaction between a spherical colloidal particle and a planar wall in a dilute solution of nonionic polymers [D. Rudhardt, C. Bechinger, and P. Leiderer, Phys. Rev. Lett. 81, 1330 (1998)].Comment: 17 pages, 3 figures. Final version as publishe

Seasonal changes in patterns of gene expression in avian song control brain regions.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Photoperiod and hormonal cues drive dramatic seasonal changes in structure and function of the avian song control system. Little is known, however, about the patterns of gene expression associated with seasonal changes. Here we address this issue by altering the hormonal and photoperiodic conditions in seasonally-breeding Gambel's white-crowned sparrows and extracting RNA from the telencephalic song control nuclei HVC and RA across multiple time points that capture different stages of growth and regression. We chose HVC and RA because while both nuclei change in volume across seasons, the cellular mechanisms underlying these changes differ. We thus hypothesized that different genes would be expressed between HVC and RA. We tested this by using the extracted RNA to perform a cDNA microarray hybridization developed by the SoNG initiative. We then validated these results using qRT-PCR. We found that 363 genes varied by more than 1.5 fold (>log(2) 0.585) in expression in HVC and/or RA. Supporting our hypothesis, only 59 of these 363 genes were found to vary in both nuclei, while 132 gene expression changes were HVC specific and 172 were RA specific. We then assigned many of these genes to functional categories relevant to the different mechanisms underlying seasonal change in HVC and RA, including neurogenesis, apoptosis, cell growth, dendrite arborization and axonal growth, angiogenesis, endocrinology, growth factors, and electrophysiology. This revealed categorical differences in the kinds of genes regulated in HVC and RA. These results show that different molecular programs underlie seasonal changes in HVC and RA, and that gene expression is time specific across different reproductive conditions. Our results provide insights into the complex molecular pathways that underlie adult neural plasticity

Water Filtration Using Plant Xylem

Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees – a readily available, inexpensive, biodegradable, and disposable material – can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings

Epidemiology and management of oesophageal coin impaction in children

The epidemiology of oesophageal coin impaction in children is poorly understood. We aimed to assess characteristics of patients with coin impaction and identify predictors of type of coin impacted and management strategies