Activation of neutrophil respiratory burst by cytokines and chemoattractants. Regulatory role of extracellular matrix glycoproteins

OBJECTIVE AND DESIGN: We investigated the in vitro responsiveness of neutrophils adherent to fibronectin (FN) and laminin (LM), toward natural pro-inflammatory and/or phagocyte-activating agents. MATERIALS AND METHODS: Neutrophils from normal volunteers were layered on polystyrene wells precoated or not with FN and/or LM and tested for their ability of responding to eleven pro-inflammatory mediators by evaluation of superoxide anion (O2-) production and adherence. Results, expressed as mean +/-1SEM, were evaluated by non-parametric analyses (Mann-Whitney U-test or Kruskal-Wallis non-parametric ANOVA analysis) RESULTS: Precoating polystyrene wells with LM or FN prevented the plastic-induced neutrophil (O2-) production. Among eleven agents, tumor necrosis factor-alpha (TNF, 3.0+/-0.3 nmoles (O2-)/5 x 10(4) neutrophils/180 min, p < 0.001), granulocyte-macrophage colony stimulating factor (GM-CSF, 2.1+/-0.3 nmoles (O2-)/5 x 10(4) neutrophils/180 min, p < 0.05) and formyl-peptides (fMLP, 2.5+/-0.5 nmoles (O2-)/5 x 10(4) neutrophils/180min, p < 0.01) caused massive (O2-) production by neutrophils adherent to FN. None of the mediators was capable of triggering (O2-) production by neutrophils adherent to LM. LM, mixed with FN to coat wells, caused a dose-dependent inhibition of the oxidative burst triggered by TNF (IC50 LM: 0.84+/-0.03 microg, mean+/-1 SEM), GM-CSF (IC50 LM: 0.36+/-0.16micro/g, mean+/-1SEM) and fMLP (IC50 LM: 0.54+/-0.008 microg, mean+/-1 SEM). To the contrary, fMLP (85.5+/-27.7%), TNF (163.1+/-67.5%), and GM-CSF (121.8+/-66.4%) caused a significant augmentation of neutrophil adherence to LM, suggesting that LM-mediated inhibition of neutrophil oxidative metabolism does not depend on the concomitant LM-induced inhibition of neutrophil adherence. Finally, neither solid-phase FN nor LM affected (O2-) production by neutrophils in response to immune complexes. CONCLUSIONS: Extracellular matrix glycoproteins dictate the response of neutrophils to soluble mediators but not to immune complexes. This appears to be a biologically meaningful mechanism to localise the risk of cellular reactions to mediators that are able to diffuse easily from tissue sites of generation and become widely distributed in body fluids during inflammatory diseases.     

Implementation of Porous Media Formulation for Geomaterials

The mechanical behavior of saturated geomaterials is largely governed by the interaction of the solid skeleton with the fluids present in the pore structure. Traditional geotechnical analyses, commonly based on simplified effective stress theories, fail to fully describe the behavior of saturated porous materials. Hence, it has become necessary to use more robust and complete formulations. In this context, the use of multiphase theories appears to be an alternative and more appropriate approach. In this work, the governing equations of a porous media interacting with immiscible porous fluids are presented in the light of the theory of mixtures. A generalized Galekin procedure is devised to establish the coupled mixed finite-element equation set with u-p-U form. An unconditionally stable implicit solution procedure is used for the time domain numerical solution. Finally, a recently developed constitutive model based on the fuzzy set plasticity concept is described and implemented in the finite-element tool. A companion paper focuses on applications of this theory, and case studies are used to evaluate the proposed formulation.     

Depressive personality characteristics: State dependent concomitants of depressive disorder and traits independent of current depression.

Depressive personality disorder (DPD) characteristics may reflect both state dependent concomitants and traits independent of current depression. In all, 30 clinically, 30 formerly, and 30 never depressed participants were given the Diagnostic Interview for Depressive Personality (J. G. Gunderson, K. A. Phillips, J. Triebwasser, & R. M. A. Hirschfeld, 1994). Negative reactivity, remorsefulness, a limited capacity for fun, gloominess, pessimism, difficulty being critical or angry, unassertiveness, self-denial, and seriousness differentiated depressed and nondepressed participants, indicating that they are primarily concomitants of depression. Self-criticalness differentiated formerly from never depressed participants after subclinical symptoms were controlled, suggesting that it is a trait independent of current depression. Low self-esteem, feeling burdened, and counterdependency manifested both state and trait components. If DPD is placed on Axis II, it should be defined by traits at least partly independent of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Applicability of Conventional p-y Relations to the Analysis of Piles in Laterally Spreading Soil

This paper presents a kinematic analysis of a single pile embedded in a laterally spreading layered soil profile and discusses the relevancy of conventional analysis models to this load case. The research encompasses the creation of three-dimensional (3D) finite-element (FE) models using the OpenSees FE analysis platform. These models consider a single pile embedded in a layered soil continuum. Three reinforced concrete pile designs are considered. The piles are modeled using beam-column elements and fiber-section models. The soil continuum is modeled using brick elements and a Drucker-Prager constitutive model. The soil-pile interface is modeled using beam-solid contact elements. The FE models are used to evaluate the response of the soil-pile system to lateral spreading and two alternative lateral load cases. Through the computation of force density-displacement (p-y) curves representative of the soil response, the FE analysis (FEA) results are used to evaluate the adequacy of conventional p-y curve relationships in modeling lateral spreading. It is determined that traditional p-y curves are unsuitable for use in analyses where large pile deformations occur at depth.