Modeling the Afferent Dynamics of the Baroreflex Control System

In this study we develop a modeling framework for predicting baroreceptor firing rate as a function of blood pressure. We test models within this framework both quantitatively and qualitatively using data from rats. The models describe three components: arterial wall deformation, stimulation of mechanoreceptors located in the BR nerve-endings, and modulation of the action potential frequency. The three sub-systems are modeled individually following well-established biological principles. The first submodel, predicting arterial wall deformation, uses blood pressure as an input and outputs circumferential strain. The mechanoreceptor stimulation model, uses circumferential strain as an input, predicting receptor deformation as an output. Finally, the neural model takes receptor deformation as an input predicting the BR firing rate as an output. Our results show that nonlinear dependence of firing rate on pressure can be accounted for by taking into account the nonlinear elastic properties of the artery wall. This was observed when testing the models using multiple experiments with a single set of parameters. We find that to model the response to a square pressure stimulus, giving rise to post-excitatory depression, it is necessary to include an integrate-and-fire model, which allows the firing rate to cease when the stimulus falls below a given threshold. We show that our modeling framework in combination with sensitivity analysis and parameter estimation can be used to test and compare models. Finally, we demonstrate that our preferred model can exhibit all known dynamics and that it is advantageous to combine qualitative and quantitative analysis methods

Abluftbehandlung bei MBA und Deponiebetrieb - Konsequenzen fuer die Praxis 62. Informationsgespraech des ANS e.V.

Seit dem 1. Maerz 2001 ist die Artikelverordnung rechtswirksam. Sie enthaelt Anforderungen an den Bau und Betrieb von mechanisch-biologischen Restabfallbehandlungsanlagen und Deponien. Die Abfallablagerungsverordnung hat darueber hinaus weitreichende Konsequenzen fuer die Betriebsdauer bestehender Deponien. Ziel der Tagung ist es, aktuelle Informationen aus laufenden Forschungs- und Entwicklungsvorhaben sowie Erfahrungen bei der praktischen Umsetzung zu praesentieren, die insbesondere zu den Themenkomplexen Abluftemissionen und Deponierung zur Zeit in Oesterreich und Deutschland vorliegen. (orig.)The new German Landfill Ordinance of 1 March 2001 specifies the requirements on construction and operation of mechanical-biological waste treatment plants and landfills as well as the continued operation of existing landfills. The conference provided current information of R + D projects as well as practical experience in Austria and Germany, with particular regard to the issues of off-air emissions and landfilling.SIGLEAvailable from TIB Hannover: RO 2405(42) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Leptospira and Inflammation

Leptospirosis is an important zoonosis and has a worldwide impact on public health. This paper will discuss both the role of immunogenic and pathogenic molecules during leptospirosis infection and possible new targets for immunotherapy against leptospira components. Leptospira, possess a wide variety of mechanisms that allow them to evade the host immune system and cause infection. Many molecules contribute to the ability of Leptospira to adhere, invade, and colonize. The recent sequencing of the Leptospira genome has increased our knowledge about this pathogen. Although the virulence factors, molecular targets, mechanisms of inflammation, and signaling pathways triggered by leptospiral antigens have been studied, some questions are still unanswered. Toll-like receptors (TLRs) are the primary sensors of invading pathogens. TLRs recognize conserved microbial pattern molecules and activate signaling pathways that are pivotal to innate and adaptive immune responses. Recently, a new molecular target has emerged—the Na/K-ATPase—which may contribute to inflammatory and metabolic alteration in this syndrome. Na/K-ATPase is a target for specific fatty acids of host origin and for bacterial components such as the glycolipoprotein fraction (GLP) that may lead to inflammasome activation. We propose that in addition to TLRs, Na/K-ATPase may play a role in the innate response to leptospirosis infection