It takes guts for tolerance: The phenomenon of oral tolerance and the regulation of autoimmune response

The intestinal tract is a peculiar environment due to its constant contact with the microbiota agents, food antigens and other molecules. Such exposure requires the establishment of important regulatory mechanisms in order to avoid inflammatory response and self aggression. In this context, the GALT plays a very relevant role due to the presence of several different cellular populations which are the main players in this phenomenon. Moreover, it was described a while ago that the oral ingestion of a given molecule is able to induce systemic tolerance to the same molecule when it is used as an immunogen by parenteral route, known as oral tolerance. This observation led researches to use these mechanisms to induce tolerance against cognate antigens of different autoimmune diseases. In this context, in this review we focused on several tolerance inducing mechanisms which are relevant not only for the maintenance of intestinal tract but also for the suppression of T effector cells, such as Th1, Th2 and the newly described Th17 cells. To name a few, CD103(+) dendritic cells, Tr1 cells derived IL-10 secretion, Foxp3 conversion and CD4(+)LAP(+) regulatory cells induction are among the recently described features of the tolerogenic environment of the intestinal tract. (C) 2009 Elsevier B.V. All rights reserved.

Evaluation of a bounded high order upwind scheme for 3D incompressible free surface flow computations

fit the context of normalized variable formulation (NVF) of Leonard and total variation diminishing (TVD) constraints of Harten. this paper presents an extension of it previous work by the authors for solving unsteady incompressible flow problems. The main contributions of the paper are threefold. First, it presents the results of the development and implementation of a bounded high order upwind adaptative QUICKEST scheme in the 3D robust code (Freeflow), for the numerical solution of the full incompressible Navier-Stokes equations. Second, it reports numerical simulation results for 1D hock tube problem, 2D impinging jet and 2D/3D broken clam flows. Furthermore, these results are compared with existing analytical and experimental data. And third, it presents the application of the numerical method for solving 3D free surface flow problems. (C) 2007 IMACS. Published by Elsevier B.V. All rights reserved,