Transforming growth factor-beta stimulation of lung fibroblast prostaglandin E2 production.

Transforming growth factor-beta (TGF beta) stimulated the production of total protein, collagen, and fibronectin by normal human lung fibroblasts. The stimulatory response was maximal at 100 pM TGF beta and reversed toward control at higher concentrations. Inhibition of fibroblast prostaglandin (PG) synthesis enhanced TGF beta-induced stimulation of total protein, collagen, and fibronectin production and reversed the negative slope of the dose-response curve at high concentrations of TGF beta. Determination of the steady-state levels of Types I and III procollagens and fibronectin mRNAs employing specific cDNA probes demonstrated that inhibition of fibroblast PG production increased the stimulatory effect of TGF beta on the levels of these transcripts. Exogenous PGE2 abrogated the stimulatory effects of TGF beta. These findings suggest that fibroblast stimulation by TGF beta may be down-regulated by endogenous PG synthesized in response to TGF beta. This notion was supported by the demonstration that TGF beta markedly stimulated fibroblast PGE2 production. These results indicate that TGF beta-induced stimulation of fibroblast PGE2 production may be an autoregulatory control mechanism to limit the effects of TGF beta on connective tissue protein synthesis

A Formal Definition of Perfect Bayesian Equilibrium for Extensive Games

Often, perfect bayesian equilibrium is loosely defined by stating that players should be sequentially rational given some beliefs in which Bayes rule is applied “whenever possible”. We show that there are games in which it is not clear what “whenever possible” means. Then, we provide a simple definition of perfect bayesian equilibrium for general extensive games that refines both weak perfect equilibrium and subgame perfect equilibrium.non-cooperative game theory, equilibrium concepts, perfect bayesian, Bayes rule.

Gender differences and the timing of first marriages

In this article we provide a simple model of the marriage market where singles search for spouses. In our model economy men and women live for many years and they differ in their survival probabilities, in their fecundity, and in their earnings. We show that modelling the marriage decision in a very simple model economy is sufficient to account for much of the observed marriage behavior in the United States in the year 2000. We conclude that gender differences in fecundity are all important in accounting for marriage behavior, and that differences in earnings matter little. We also conclude that, even though they are in short supply, the market power of fecund women is not enough for them to demand compensation in all cases. And that studying the marriage decision without modelling explicitly the roles played by age and by fecundity, as has been typically done by the previous literature, makes little sense.Marriage, Search, Sex ratio

Alternative splicing of human prostaglandin G/H synthase mRNA and evidence of differential regulation of the resulting transcripts by transforming growth factor beta 1, interleukin 1 beta, and tumor necrosis factor alpha.

Prostaglandin G/H synthase (PGG/HS) is the rate-limiting enzyme in the conversion of arachidonic acid to prostaglandins and thromboxanes. We screened a human lung fibroblast cDNA library with an ovine PGG/HS cDNA and isolated a 2.3-kilobase clone (HCO-T9). Sequence analysis of this clone showed that (a) it contained the entire translated region of PGG/HS and (b) it displayed an in-frame splicing of the last 111 base pairs encoded by exon 9, which resulted in the elimination of the N-glycosylation site at residue 409. Polymerase chain reaction amplification with specific oligonucleotides of reverse-transcribed mRNA from diverse human tissues and cultured cells yielded 400- and 300-base pair fragments that corresponded, respectively, to the intact and spliced transcripts. The expression of these two transcripts in cultured human lung fibroblasts was differentially regulated by serum, transforming growth factor beta 1, interleukin 1 beta, tumor necrosis factor alpha, and phorbol 12-myristate 13-acetate, as each of these conditions stimulated preferentially the expression of the unspliced transcripts. The elimination of one of the four N-glycosylation sites by the alternative splicing of exon 9 and the differential regulation of this process by relevant cytokines and growth factors may represent a mechanism for the regulation of PGG/HS enzymatic activity under physiological or pathological conditions

Phantom inflation and the "Big Trip"

Primordial inflation is regarded to be driven by a phantom field which is here implemented as a scalar field satisfying an equation of state $p=\omega\rho$, with $\omega<-1$. Being even aggravated by the weird properties of phantom energy, this will pose a serious problem with the exit from the inflationary phase. We argue however in favor of the speculation that a smooth exit from the phantom inflationary phase can still be tentatively recovered by considering a multiverse scenario where the primordial phantom universe would travel in time toward a future universe filled with usual radiation, before reaching the big rip. We call this transition the "big trip" and assume it to take place with the help of some form of anthropic principle which chooses our current universe as being the final destination of the time transition.Comment: 23 pages, 5 figures, LaTex, Phys. Lett. B (in press

3D Well-composed Polyhedral Complexes

A binary three-dimensional (3D) image $I$ is well-composed if the boundary surface of its continuous analog is a 2D manifold. Since 3D images are not often well-composed, there are several voxel-based methods ("repairing" algorithms) for turning them into well-composed ones but these methods either do not guarantee the topological equivalence between the original image and its corresponding well-composed one or involve sub-sampling the whole image. In this paper, we present a method to locally "repair" the cubical complex $Q(I)$ (embedded in $\mathbb{R}^3$) associated to $I$ to obtain a polyhedral complex $P(I)$ homotopy equivalent to $Q(I)$ such that the boundary of every connected component of $P(I)$ is a 2D manifold. The reparation is performed via a new codification system for $P(I)$ under the form of a 3D grayscale image that allows an efficient access to cells and their faces

Epidermal growth factor coordinately regulates the expression of prostaglandin G/H synthase and cytosolic phospholipase A2 genes in embryonic mouse cells.

Confluent, primary cultures of mouse embryo palate mesenchyme (MEPM) cells are refractory to activation of phospholipase A2 (PLA2) by the calcium ionophore A23187. However, treatment of these cultures with epidermal growth factor (EGF) permits the cells to activate PLA2 in response to A23187. We have developed this finding by exploring molecular mechanisms by which growth factors modulate mobilization and metabolism of arachidonic acid. We found chronic treatment (\u3e 6 h) of confluent MEPM cells with EGF (a) increases their ability to metabolize exogenous arachidonic acid to prostaglandin E2 (PGE2) and (b) stimulated constitutive expression of activities of PLA2 and cyclooxygenase (CyOx). Immunoprecipitation of [35S]proteins and Western blot analysis revealed EGF treatment stimulated synthesis and accumulation of PLA2c, CyOx-1, and CyOx-2. Northern hybridization analysis revealed EGF increased the steady-state levels of a transcript for the high molecular weight, cytosolic PLA2 (PLA2c), and both the 2.8- and 4.2-kb transcripts for CyOx-1 and CyOx-2, respectively. In vitro nuclear transcription assays showed a parallel increase in the transcription rate of the genes corresponding to CyOx-1 and PLA2c, but not CyOx-2, in response to EGF. Treatment with EGF had no effect on either synthesis of the low molecular weight, group II PLA2, accumulation of its transcript, or the transcription rate of its gene. Coordinate regulation of activities of PLA2 and CyOx in response to EGF did not parallel the mitogenic effects of EGF on confluent MEPM cells

Modelling of microwave induced plasmas : the interplay between electromagnetism, plasma chemistry and transport

In this thesis we report on a theoretical/numerical study that is concerned with Microwave Induced Plasmas (MIPs) in general, and the application of a MIP to the Plasma-activated Chemical Vapour Deposition (PCVD) process that is used at Draka Comteq for the production of optical fibres in particular. This was performed in the framework of the STW project (ETF.6265) titled: Exploring the compositional freedom in space and chemistry of Microwave Induced Plasmas: An object oriented approach. The primary purpose of the project was to design an experimentally validated grand model for the microwave deposition plasma. Furthermore, in order to improve the deposition process, we studied how the different microwave components shape the electromagnetic field and thus the plasma. To deal with these objectives, two types of models have been used: 1. Models describing particular aspects. The Electromagnetic Model (chapter 3) is based on the finite difference frequency domain method and makes use of a two-dimensional orthocurvilinear grid. It is a full-vectorial approach for 3-field components that can be used as a design tool for symmetrical electromagnetic structures (chapter 6) and as a crucial part of Grand Models. The Electromagnetic Model was validated by means of a comparison of its results with those of known waveguide solutions. The Chemistry Model (chapter 5) is a zero space-dimensional version of a Grand Model giving a time-dependent description of the chemical plasma composition. The transport mechanisms, in reality originating from two or three dimensional structures, are described in the framework of the Chemistry model as effective source terms making use of convection and diffusion requencies. In this thesis we deal with a Chemistry Model for pulsed plasmas. The Deposition Model (chapter 11) has been developed as a tool for obtaining insight into the role of the plasmas used for optical fibre production. The model shows how plasma mechanisms such as diffusion and convection manifest themselves in the local deposition profile. The global deposition profile is the result of the convolution of various local profiles. This convolution is realized by the movement of the plasma-creating cavity along the tube in which the deposition takes place. Results of the global profile are compared with those of experimental measurements. 2. Models describing multiple aspects in a self-consistent manner using the insights of the electromagnetic, chemical and deposition aspects, a more complete plasma model is created. This so-called Grand Model (chapter 7) consists of a macroscopic description of plasmas based on balance equations (chapter 4) that compute the chemical composition in a self-consistent relation with the flow and the electromagnetic aspects. The boundary conditions are formed by the configuration of the plasma, the absorbed power, the overall pressure difference and the fill-chemistry. Two-dimensional Grand Models are created using the PLASIMO platform (described in chapter 2). A central role is played by the Electromagnetic Model described above, which is needed to describe the power absorbed by the plasma. The Grand Model has been validated by comparing it with experimental results of surface wave discharges (chapters 8 and 9) thus fulfilling the first objective of this study. Furthermore in chapter 10, it is used to investigate the confinement of the plasma inside the Draka reactor