561 research outputs found
P479Extracellular S100A4 induces arterial smooth muscle cell activation in a RAGE-dependent manner
Background: It has been proposed that smooth muscle cells (SMCs) from the arterial wall are heterogeneous and that only a subset of medial SMCs are prone to accumulate into the intima leading to atheromatous plaque formation. We isolated 2 distinct SMC phenotypes from porcine coronary artery: spindle-shaped (S) and rhomboid (R). Biological features of R-SMCs (i.e. enhanced proliferative and migratory activities as well as poor level of differentiation) explain their capacity to accumulate into the intima. We identified S100A4 as being a marker of the R-SMCs in vitro and of intimal SMCs, both in pig and human. S100A4 is a Ca2+-binding protein that can also be secreted; it has extracellular functions probably via the receptor for advanced glycation end products (RAGE). Purpose: Explore the role of S100A4 in SMC phenotypic change, a phenomenon characteristic of atherosclerotic plaque formation. Methods and Results: Transfection of a human S100A4-containing plasmid in spindle-shaped (S) SMCs (devoid of S100A4) led to approximately 10% of S100A4-overexpressing SMCs, S100A4 release, and a transition towards a R-phenotype of the whole SMC population. Furthermore treatment of S-SMCs with S100A4-rich conditioned medium collected from S100A4-transfected S-SMCs induced a transition towards a phenotype typical of the R-SMCs, which was associated with decreased SMC differentiation markers, increased proliferation and migration, as well as induced proteolytic activity through activation of urokinase-type plasminogen activator (uPA), matrix metalloproteinases (MMP-1,-2, -3, and -9) and their inhibitors (TIMP-1). Furthermore, extracellular S100A4 yielded activation of NF-kB in a RAGE-dependent manner. Blockade of extracellular S100A4 in R-SMCs with S100A4 neutralizing antibody induced a transition from R- to S-phenotype, decreased proliferative activity and upregulation of SMC differentiation markers. In contrast, silencing of S100A4 mRNA in R-SMCs did not change the level of extracellular S100A4 nor SMC morphology in spite of decreased proliferative activity. Conclusions: Our results indicate that SMC phenotypic changes are essentially dependent on extracellular S100A4 activity. It could be a new target to prevent SMC accumulation during atherosclerosis and restenosi
Ranking Templates for Linear Loops
We present a new method for the constraint-based synthesis of termination
arguments for linear loop programs based on linear ranking templates. Linear
ranking templates are parametrized, well-founded relations such that an
assignment to the parameters gives rise to a ranking function. This approach
generalizes existing methods and enables us to use templates for many different
ranking functions with affine-linear components. We discuss templates for
multiphase, piecewise, and lexicographic ranking functions. Because these
ranking templates require both strict and non-strict inequalities, we use
Motzkin's Transposition Theorem instead of Farkas Lemma to transform the
generated -constraint into an -constraint.Comment: TACAS 201
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Using a runway paradigm to assess the relative strength of rats' motivations for enrichment objects
Laboratory animals should be provided with enrichment objects in their cages; however, it is first necessary to
test whether the proposed enrichment objects provide benefits that increase the animals’ welfare. The two main
paradigms currently used to assess proposed enrichment objects are the choice test, which is limited to determining
relative frequency of choice, and consumer demand studies, which can indicate the strength of a preference but are complex to design. Here, we propose a third methodology: a runway paradigm, which can be used to assess the strength of an animal’s motivation for enrichment objects, is simpler to use than consumer demand studies, and is faster to complete than typical choice tests. Time spent with objects in a standard choice test was used to rank several enrichment objects in order to compare with the ranking found in our runway paradigm. The rats ran significantly more times, ran faster, and interacted longer with objects with which they had previously spent the most time. It was concluded that this simple methodology is suitable for measuring rats’ motivation to reach enrichment objects. This can be used to assess the preference for different types of enrichment objects or to measure reward system processes
Detergents and chaotropes for protein solubilization before two-dimensional electrophoresis
Because of the outstanding ability of two-dimensional electrophoresis to
separate complex mixtures of intact proteins, it would be advantageous to apply
it to all types of proteins, including hydrophobic and membrane proteins.
Unfortunately, poor solubility hampers the analysis of these molecules. As
these problems arise mainly in the extraction and isoelectric focusing steps,
the solution is to improve protein solubility under the conditions prevailing
during isoelectric focusing. This chapter describes the use of chaotropes and
novel detergents to enhance protein solubility during sample extraction and
isoelectric focussing, and discusses the contribution of these compounds to
improving proteomic analysis of membrane proteins
Unrestricted Termination and Non-Termination Arguments for Bit-Vector Programs
Proving program termination is typically done by finding a well-founded
ranking function for the program states. Existing termination provers typically
find ranking functions using either linear algebra or templates. As such they
are often restricted to finding linear ranking functions over mathematical
integers. This class of functions is insufficient for proving termination of
many terminating programs, and furthermore a termination argument for a program
operating on mathematical integers does not always lead to a termination
argument for the same program operating on fixed-width machine integers. We
propose a termination analysis able to generate nonlinear, lexicographic
ranking functions and nonlinear recurrence sets that are correct for
fixed-width machine arithmetic and floating-point arithmetic Our technique is
based on a reduction from program \emph{termination} to second-order
\emph{satisfaction}. We provide formulations for termination and
non-termination in a fragment of second-order logic with restricted
quantification which is decidable over finite domains. The resulted technique
is a sound and complete analysis for the termination of finite-state programs
with fixed-width integers and IEEE floating-point arithmetic
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