Late Crohn's disease patients present an increase in peripheral Th17 cells and cytokine production compared with early patients

[Background]: Th1 and Th17 cells have been implicated in Crohn's disease (CD) pathophysiology and may play a role in disease persistence. [Aim]: To determine Th1 and Th17 responses in intestine and peripheral blood of early (2 years) CD patients. [Methods]: Cytokine mRNA in intestinal biopsies was determined by RT-PCR. Cytokine concentration in culture was measured by ELISA and cytokine-producing cells were identified by intracellular staining. [Results]: The inflamed mucosa showed significantly increased IL-17 mRNA levels compared with non-inflamed areas, both in early and late CD patients. However, only patients with late (n = 12), but not early (n = 9), active disease showed increased IL-17 production, as well as a significantly higher percentage of IL-17+CD4+ cells in blood, compared with controls (n = 12) or patients in remission (n = 13). Moreover, cultured peripheral CD4 + cells from late active CD patients presented significantly higher percentages of IL-17+, IL-22+ and IFN-γ+ and a significantly increased production of IL-17 and IL-22, but not IFN-γ+. [Conclusions]: Increased IL-17 gene transcription is common to early and late CD mucosa. However, exacerbated Th17 responses in the peripheral blood appear only in late disease. We propose that this population may constitute a mechanism of perpetuating the disease. © 2010 Blackwell Publishing Ltd.This work was funded by grants SAF2005⁄03755 and BFU2008-02683⁄BFI to A.S. and SAF2006⁄03074 to J.P. from the Ministerio de Ciencia e Innovación, Spain. M.V. is the recipient of a FPI fellowship (SAF2005⁄03755) from the Ministerio de Ciencia e Innovación, Spain.Peer Reviewe

Modeling Dominant Height Growth in Planted Pinus pinea Stands in Northwest of Tunisia

Six generalized algebraic difference equations (GADAs) derived from the base models of log-logistic, Bertalanffy-Richards, and Lundqvist-Korf were used to develop site index model for Pinus pinea plantations in north-west of Tunisia. To assure the base-age invariance of the model parameter estimates, a dummy variable approach was used. Data from stem analysis, corrected with Carmean's method, were used for modelling. To take into account the inherent autocorrelation of the longitudinal data, a second-order continuous-time autoregressive error structure was used, which allows the models to be applied to irregularly spaced, unbalanced data. Both a qualitative analysis based on the biological realism of the models and numerical and graphical analyses based on the accuracy of the models as well were used to evaluate the performance of candidate models. The relative error in site index predictions was used to select 30 years as the best reference age. Based on the analysis, a generalized algebraic difference equation (GADA) derived from the base model of Lundqvist-Korf realized the best compromise between biological and statistical constraints, producing the most adequate site index curves. It is a polymorphic model with site-dependent asymptotes. This model is therefore recommended for height growth prediction and site classification of Pinus pinea plantations in north-west of Tunisia

Modelos de crecimiento y produccion en España: resumen histórico, ejemplos contemporaneos y perspectivas

In this paper we present a review of forest models developed in Spain in recent years for both timber and non timber production and forest dynamics (regeneration, mortality,..). Models developed are whole stand, size (diameter) class and individual-tree. The models developed to date have been developed using data from permanent plots, experimental sites and the National Forest Inventory. In this paper we show the different sub-models developed so far and the friendly use software. Main perspectives of forest modelling in Spain are presented.En el presente trabajo se presenta una revisión sobre los modelos forestales desarrollados en España durante los últimos años tanto para la producción maderable como no maderable y para la dinámica de los bosques (regeneración, mortalidad,..). Se presentan modelos tanto de rodal completo como de clases diamétricas y de árbol individual Los modelos desarrollados hasta la fecha se han desarrollado a partir de datos procedentes de parecelas permanentes, ensayos y el Inventario Forestal Nacional. En el presenta trabajo se muestran los diferentes submodelos desarrollados hasta la fecha asi como las plataformas informáticas que permiten utilizar de forma amigable los modelos. Se incluyen las principales perspectivas de desarrollo de la modelización forestal en España