An infrared reflection-absorption spectroscopic (IRRAS) study of the interaction of lipid A and lipopolysaccharide Re with endotoxin-binding proteins.

Lipopolysaccharides (LPS, endotoxins) are main constituents of the outer membranes of Gram-negative bacteria, with the 'endotoxic principle' lipid A anchoring LPS into the membrane. When LPS is removed from the bacteria by the action of the immune system or simply by cell dividing, it may interact strongly with immunocompetent cells such as mononuclear cells. This interaction may lead, depending on the LPS concentration, to beneficial (at low) or pathophysiological (at high concentrations) reactions, the latter frequently causing the septic shock syndrome. There is a variety of endogenous LPS-binding proteins. To this class belong lactoferrin (LF) and hemoglobin (Hb), which have been shown to suppress and enhance the LPS-induced cytokine secretion in mononuclear cells, respectively. To elucidate the interaction mechanisms of endotoxins with these proteins, we have investigated in an infrared reflection-absorption spectroscopy (IRRAS) study the interaction of LPS or lipid A monolayers at the air/water interface with LF and Hb proteins, injected into the aqueous subphase. The data are clearly indicative of completely different interaction mechanisms of the endotoxins with the proteins, with the LF acting only at the LPS backbone, whereas Hb incorporates into the lipid monolayer. These data allow an understanding of the different reactivities in the biomedicinal systems.

Recommandations de pratique clinique dans la schizophrénie: de la théorie à la mise en application = Clinical practice guidelines for the treatment of schizophrenia: from theory to practice

Dans le cadre d'une étude rétrospective au sein d'une unité de réhabilitation, nous avons cherché à examiner le degré de respect de recommandations de pratique clinique (RPC) abordant le traitement pharmacologique au long cours de la schizophrénie, par des médecins qui n'en ont qu'une connaissance indirecte. The Expert Consensus Guideline for the treatment of schizophrenia (ECGTS) a été retenu comme référence sur la base d'une comparaison avec cinq autres RPC principales. Sur un collectif de 20 patients, les recommandations de l'ECGTS sont totalement respectées dans 65 % des cas, partiellement respectées dans 10 % et non respectées dans 25 %, démontrant ainsi que la pratique clinique est clairement perfectible (principalement dans le traitement des symptômes psychotiques et dépressifs). Cependant, le respect des RPC ne garantit pas forcément la résolution de tous les problèmes cliniques rencontrés : 12 patients sur 20 présentent des effets secondaires à l'évaluation clinique et pour huit d'entre eux, les recommandations à ce niveau, sont respectées. Notre étude montre cependant que le choix et l'application d'une RPC ne sont pas simples. Les RPC actuelles donnent peu ou pas d'instruments de mesure, ni de critères précis pour évaluer les problèmes cliniques auxquels elles font référence. L'avenir appartient donc à des RPC qui proposent, outre les recommandations cliniques elles-mêmes, les moyens de leur vérification et de leur application sur le terrain.

Trypanosoma cruzi-cardiomyocytes: new contributions regarding a better understanding of this interaction

The present paper summarizes new approaches regarding the progress done to the understanding of the interaction of Trypanosoma cruzi-cardiomyocytes. Mannose receptors localized at the surface of heart muscle cell are involved in binding and uptake of the parasite. One of the most striking events in the parasite-heart muscle cells interaction is the disruption of the actin cytoskeleton. We have investigated the regulation of the actin mRNA during the cytopathology induced in myocardial cells by the parasite. T. cruzi invasion increases calcium resting levels in cardiomyocytes. We have previously shown that Ca2+ ATPase of the sarcoplasmic reticulum (SERCA) is involved in the invasion of T. cruzi in cardiomyocytes. Treating the cells with thapsigargin, a drug that binds to all SERCA ATPases and causes depletion of intracellular calcium stores, we found a 75% inhibition in the T. cruzi-cardiomyocytes invasion.

Flow cytometry as a tool to identify Mycobacterium tuberculosis interaction with the immune system and drug susceptibility

Flow cytometric analysis is a useful and widely employed tool to identify immunological alterations caused by different microorganisms, including Mycobacterium tuberculosis. However, this tool can be used for several others analysis. We will discuss some applications for flow cytometry to the study of M. tuberculosis, mainly on cell surface antigens, mycobacterial secreted proteins, their interaction with the immune system using inflammatory cells recovered from peripheral blood, alveolar and pleura spaces and the influence of M. tuberculosis on apoptosis, and finally the rapid determination of drug susceptibility. All of these examples highlight the usefulness of flow cytometry in the study of M. tuber-culosis infection.

Temperament in Bach’s Well-tempered clavier: a historical survey and a new evaluation according to dissonance theory

After a historical survey of temperament in Bach’s Well-Tempered Clavier by Johann Sebastian Bach, an analysis of the work has been made by applying a number of historical good temperaments as well as some recent proposals. The results obtained show that the global dissonance for all preludes and fugues in major keys can be minimized using the Kirnberger II temperament. The method of analysis used for this research is based on the mathematical theories of sensory dissonance, which have been developed by authors such as Hermann Ludwig Ferdinand von Helmholtz, Harry Partch, Reinier Plomp, Willem J. M. Levelt and William A. Sethares

Law and the practise of principle in diverse societies

Projecte de recerca elaborat a partir d’una estada a la London School of Economics and Political Science, United Kingdom, entre 2007 i 2009. L’objecte principal del projecte ha estat analitzar les implicacions jurídico-polítiques i institucionals d’una teoria de la justícia i la igualtat liberals aplicada a societats multiculturals amb un marcat predomini de la diversitat cultural. L’anàlisi desenvolupa una línia d'investigació interdisciplinar - entre el dret i la teoria política - iniciada en una tesis doctoral sobre multiculturalisme i drets de les minories culturals (UPF, 2000) que va culminar en la publicació de Group Rights as Human Rights (Springer, 2006). La recerca adopta com a punt de partida les conclusions de l'esmentada obra, en especial, la rellevància del reconeixement de drets col•lectius; tanmateix, el tipus de qüestions plantejades, l’enfoc i la metodologia emprades són substancialment diferents. En concret, s'adrecen preguntes específiques sobre el model i aspiracions del constitucionalisme democràtic i el paper del dret en contextos multiculturals. També s’atorga un pes central a la dimensió institucional dels models de gestió de la diversitat que s’analitzen, prioritzant un enfocament comparatiu a partir de l’estudi de controvèrsies concretes. L’objectiu és superar algunes limitacions importants de la literatura actual, com ara la tendència a examinar en abstracte la compatibilitat de determinades demandes amb el constitucionalisme democràtic, sense abordar el funcionament d'estratègies de gestió de la diversitat cultural emprades en contextos concrets. Els treballs producte d'aquest projecte articulen les línies bàsiques d’un model pluralista, basat en principis més que en regles, que desafia els plantejaments dominants actualment. Aquest model es caracteritza pel compromís amb la legitimitat i igualtat comparatives, rebutjant el paternalisme i les visions liberals típiques sobre el paper de la regulació. La presumpció de l’“standing” moral dels grups identitaris és fonamental per tal de considerar-los interlocutors vàlids amb interessos genuïns. També s’argumenta que la integració social en contextos multiculturals no depèn tant de l’eliminació del conflicte sinó, sobre tot, d’una gestió eficient que eviti abusos de poder sistemàtics. El model defensa el rol del dret en la institucionalització del diàleg intercultural, però admet que el diàleg no necessàriament condueix a l’acord o a una estructura reguladora coherent i uniforme. Les aspiracions del ordre jurídic pluralista són més modestes: afavorir la negociació i resolució en cada conflicte, malgrat la persistència de la fragmentació i la provisionalitat dels acords. La manca d'un marc regulador comú esdevé una virtut en la mesura que permet la interacció de diferents subordres; una interacció governada per una multiplicitat de regles no necessàriament harmòniques. Els avantatges i problemes d’aquest model s'analitzen a partir de l'anàlisi de l’estructura fragmentària de l'ordre jurídic internacional i del règim Europeu de drets humans.

Le code-switching comme ressource stratégique pour la gestion de l'interaction multilingue : coordination et leadership dans un groupe de travail

In this article, we analyze a multilingual interaction in a students' working group and hypothesize a correlation between management of languages in interaction and leadership. We consider Codeswitching as one of the most relevant observables in multilingual interaction and attempt to analyze how it is used by speakers. After a brief presentation of three theoretical and analytical conceptions of Code-switching in interaction (Auer, Mondada & Myers Scotton), we define Code-switching as an interactional, strategical, multilingual resource exploited by speakers to achieve various interactional and non interactional goals. We then show in two CA-like analysis how multilingual strategical resources occur in the interactional practices of the analyzed working group, and how they are exploited by speakers in order to organize interaction, work, tasks, and to construct one's leadership. We also consider the metadiscourses of the students about their own practices and multilingualism in general, in order to confront them to their actual multilingual practices. We draw the hypothesis that discrepancies observed between metadiscourses and practices can be explained through the development of (meta)discourses showing a unilingual conception in describing multilingual practices.

Photodynamic drug delivery enhancement in tumours does not depend on leukocyte-endothelial interaction in a human mesothelioma xenograft model.

OBJECTIVES: The pre-treatment of tumour neovessels by low-level photodynamic therapy (PDT) improves the distribution of concomitantly administered systemic chemotherapy. The mechanism by which PDT permeabilizes the tumour vessel wall is only partially known. We have recently shown that leukocyte-endothelial cell interaction is essential for photodynamic drug delivery to normal tissue. The present study investigates whether PDT enhances drug delivery in malignant mesothelioma and whether it involves comparable mechanisms of actions. METHODS: Human mesothelioma xenografts (H-meso-1) were grown in the dorsal skinfold chambers of 28 nude mice. By intravital microscopy, the rolling and recruitment of leukocytes were assessed in tumour vessels following PDT (Visudyne(®) 400 μg/kg, fluence rate 200 mW/cm(2) and fluence 60 J/cm(2)) using intravital microscopy. Likewise, the distribution of fluorescently labelled macromolecular dextran (FITC-dextran, MW 2000 kDa) was determined after PDT. Study groups included no PDT, PDT, PDT plus a functionally blocking anti-pan-selectin antibody cocktail and PDT plus isotype control antibody. RESULTS: PDT significantly enhanced the extravascular accumulation of FITC-dextran in mesothelioma xenografts, but not in normal tissue. PDT significantly increased leukocyte-endothelial cell interaction in tumour. While PDT-induced leukocyte recruitment was significantly blunted by the anti-pan-selectin antibodies in the tumour xenograft, this manipulation did not affect the PDT-induced extravasation of FITC-dextran. CONCLUSIONS: Low-level PDT pre-treatment selectively enhances the uptake of systemically circulating macromolecular drugs in malignant mesothelioma, but not in normal tissue. Leukocyte-endothelial cell interaction is not required for PDT-induced drug delivery to malignant mesothelioma.

In vitro interaction of Brazilian strains of the Nematode-trapping fungi Arthrobotrys spp. on Panagrellus sp. and Cooperia punctata

In vitro tests were carried out to verify the activity of 26 Brazilian isolates of predatory fungi of the genus Arthrobotrys on a free-living nematode (Panagrellus sp.) and on infective larvae of Cooperia punctata, a parasitic gastrointestinal nematode of cattle. The results showed that the free-living nematode Panagrellus sp. was the most preyed upon, compared to C. punctata, for all the fungal treatments. Also, variable predatory capacity was observed for different fungal isolates belonging to the same genus when applied to different nematode species.