Volatile organic breath components and exercise induced bronchoconstriction in asthmatic children

Abstract Introduction Asthma is one of the most common chronic diseases in childhood and is generally characterized by exercise induced bronchoconstriction (EIB). Assessing EIB is time consuming and expensive as it requires a fully equipped pulmonary function laboratory. Analysis of volatile organic compounds (VOCs) in breath is a novel technique for examining biomarkers which may associate with asthma features. The aim of this pilot study was to identify potential markers in the relationship between EIB and VOCs. Methods Children between four and 14 years old were asked to provide a breath sample prior to undergoing an exercise challenge test to assess for EIB. Results Breath samples were collected and analyzed in 46 asthmatic children, 21 with EIB and 25 without EIB (NO-EIB). Molecular features (MFs) were not significantly different between EIB and NO-EIB controls. 29 of the 46 children were corticosteroid naïve, 10 with EIB and 13 without. In the corticosteroid naïve group EIB was associated with increased MF23 and MF14 in the lower breath sample (p-value < 0.05). Conclusion This pilot study shows that EIB was related to an increased MF14 and MF23 in corticosteroid naïve children. The tentative identities of these compounds are octanal and dodecane/tetradecane respectively. These candidate biomarkers have a potential to enable non-invasive diagnosis of EIB in steroid-naïve children. Trial registration This study is registered in the Netherlands trial register (trial no. NL6087) at 14 February 2017

Regulation of chloride transport in cultured normal and cystic fibrobis keratinocytes

Abstract Cultured normal (N) and cystic fibrosis (CF) keratinocytes were evaluated for their Cl−-transport properties by patch-clamp-, Ussing chamber- and isotopic efflux-measurements. Special attention was paid to a 32 pS outwardly rectifying Cl− channel which has been reported to be activated upon activation of cAMP-dependent pathways in N, but not in CF cells. This depolarization-induced Cl− channel was found with a similar incidence in N and CF apical keratininocyte membranes. However, activation of this channel in excised patches by protein kinase (PK)-A or PK-C was not successfull in either N or CF keratinocytes. Forskolin was not able to activate Cl− channels in N and CF cell-attached patches. The Ca2+-ionophore A23187 activated in cell-attached patches a linear 17 pS Cl− channel in both N and CF cells. This channel inactivated upon excision. No relationship between the cell-attached 17 pS and the excised 32 pS channel could be demonstrated. Returning to the measurement of Cl− transport at the macroscopic level, we found that a drastic rise in intracellular cAMP induced by forskolin did in N as well as CF cells not result in a change in the short-circuit current (Isc) or the fractional efflux rates of 36Cl− and 125I−. In contrast, addition of A23187 resulted in an increase of the Isc and in the isotopic anion efflux rates in N and CF cells. We conclude that Cl−-transport in cultured human keratinocytes can be activated by Ca2+, but not by cAMP-dependent pathways

Modeling the Dynamic Effects of Discourse: Principles and Frameworks

International audienceWhen studying the meaning of natural language expressions, sentence level provides a natural entry point. Its relevance of course depends on the focus we want to put on the meaning: as related to thought, to communication, to truth, etc. In this paper, we concentrate on the model theoretic view on meaning, in particular via first order logic representation. More specifically, we present phenomena that illustrate the challenges raised by discourse to truth-conditional semantics and compositionality. We show that proposals to address theses challenges rely on the additional device of contexts and on the way sentences can access and modify these contexts. This capability is usually referred to as the context change potential of a sentence. Depending on the phenomenon, the contexts need to represent different kinds of information: propositions, discourse referents, and variations on these elements. We also show that taking into account the rhetorical structure of discourse leads to even richer structuring of the context. Parallel to the presentation of the phenomena, we concentrate on formalisms giving an account of the dynamics of discourse. We introduce the well established formalisms of Discourse Representation Theory (DRT) Dynamic Predicate Logic (DPL) , and the more recently developed approach based on continuation semantics. Finally, we introduce Segmented Discourse Representation Theory (SDRT) that combines the effects of dynamics and discourse structure.La phrase représente un niveau d'entrée naturel dans l'étude du sens des expressions de la langue naturelle. Sa pertinence dépend bien sûr de la perspective que l'on souhaite mettre en avant sur le sens : celle relative à la pensée, celle relative à la communication, celle relative à la valeur de vérité... Dans cet article, nous nous concentrons sur la perspective donnée au sens par la théorie des modèles, en particulier par la représentation avec la logique du premier ordre. Plus spécifiquement, nous présentons des phénomènes illustrant les difficultés posées par le discours à la sémantique vériconditionnelle et à la compositionalité. Nous montrons que les propositions pour répondre à ces difficultés reposent sur l'utilisation de contextes et de la manière dons les phrases peuvent accéder à ce contexte et le modifier. Ce mécanisme est généralement appelé potentiel de changement du contexte d'une phrase. Suivant le phénomène considéré, le contexte doit représenter différents types d'informations : des propositions, des référents de discours, et des variations de ces éléments. Nous montrons également que la prise en compte de la structure rhétorique du discours conduit à une représentation encore plus riche du contexte. Parallèlement à l'exposé de ces phénomènes, nous présentons différents formalismes qui en rendent compte. Nous présentons la théorie des représentations discursives (DRT), de la logique des prédicats dynamique (DPL), ainsi que l'approche fondée sur les continuations proposée plus récemment. Enfin nous présentons la théorie des représentations discursives segmentées (SDRT) qui combine les effets de la dynamique et de la structure discursive

The process of short- and long-term price integration in the Benin maize market.

This paper reviews the methodology used to study the price integration process in spatially separated spot markets, and applies it to the Benin maize market. An autoregressive distributed lag model is derived to take into account the sluggishness of price adjustments. Hypothesis testing concerns stationarity and both long- and short-term integration of the price series. Long-term integration is tested with co-integration analysis. Error correction models are used to test for short-run integration and to estimate the speed of price adjustment. It is concluded that the arbitrage system is functioning, but with a significant time lag for several markets. This implies that there is scope for improving market performance. -Author