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Differential Levels (differential + level)
Selected AbstractsDifferential levels of tissue hypoxia in the developing chicken heartDEVELOPMENTAL DYNAMICS, Issue 1 2006Jamie Wikenheiser Abstract Tissue hypoxia plays a critical role in normal development, including cardiogenesis. Previously, we showed that oxygen concentration, as assessed by the hypoxia indicator EF5, is lowest in the outflow tract (OFT) myocardium of the developing chicken heart and may be regulating events in OFT morphogenesis. In this study, we identified additional areas of the embryonic chicken heart that were intensely positive for EF5 within the myocardium in discrete regions of the atrial wall and the interventricular septum (IVS). The region of the IVS that is EF5-positive includes a portion of the developing central conduction system identified by HNK-1 co-immunostaining. The EF5 positive tissues were also specifically positive for nuclear-localized hypoxia inducible factor 1, (HIF-1,), the oxygen-sensitive component of the hypoxia inducible factor 1 (HIF-1) heterodimer. The pattern of the most intensely EF5-stained myocardial regions of the atria and IVS resemble the pattern of the major coronary vessels that form in later stages within or immediately adjacent to these particular regions. These vessels include the sinoatrial nodal artery that is a branch of the right coronary artery within the atrial wall and the anterior/posterior interventricular vessels of the IVS. These findings indicate that a portion of the developing central conduction system and the patterning of coronary vessels may be subject to a level of regulation that is dependent on differential oxygen concentration within cardiac tissues and subsequent HIF-1 regulation of gene expression. Developmental Dynamics 235:115,123, 2006. © 2005 Wiley-Liss, Inc. [source] Block factorized preconditioners for high-order accurate in time approximation of the Navier-Stokes equationsNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 4 2003Alessandro Veneziani Computationally efficient solution methods for the unsteady Navier-Stokes incompressible equations are mandatory in real applications of fluid dynamics. A typical strategy to reduce the computational cost is to split the original problem into subproblems involving the separate computation of velocity and pressure. The splitting can be carried out either at a differential level, like in the Chorin-Temam scheme, or in an algebraic fashion, like in the algebraic reinterpretation of the Chorin-Temam method, or in the Yosida scheme (see 1 and 19). These fractional step schemes indeed provide effective methods of solution when dealing with first order accurate time discretizations. Their extension to high order time discretization schemes is not trivial. To this end, in the present work we focus our attention on the adoption of inexact algebraic factorizations as preconditioners of the original problem. We investigate their properties and show that some particular choices of the approximate factorization lead to very effective schemes. In particular, we prove that performing a small number of preconditioned iterations is enough to obtain a time accurate solution, irrespective of the dimension of the system at hand. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 487,510, 2003 [source] Changes in fungicide sensitivity and relative species abundance in Oculimacula yallundae and O. acuformis populations (eyespot disease of cereals) in Western EuropePLANT PATHOLOGY, Issue 3 2008S. Parnell Changing fungicide sensitivities in populations of Oculimacula yallundae and O. acuformis, the species responsible for cereal eyespot in Western Europe, were determined over a 17 year period between 1984 and 2000. The data were collected by Aventis Crop Science as part of their long-term survey to monitor changes in sensitivity to prochloraz and the methyl benzimidazole carbamate (MBC) fungicides in eyespot populations. The results show evidence for reduced sensitivity to both fungicides over the period of the survey. The decline in MBC sensitivity is in agreement with reports of practical resistance (a detectable loss of disease control in the field) to this fungicide which were widely reported from the mid 1980s onward. Prochloraz sensitivity was more complex, with the emergence of a higher resistance category of isolates in the late 1980s and early 1990s which then decreased in frequency towards the end of the survey. This may be partly explained by the introduction and increased use of cyprodinil in the mid 1990s. Although all trends were similar across Europe, differences were observed between the two eyespot species. A higher frequency of O. yallundae isolates showed decreased sensitivity to MBC, whereas decreased sensitivity to prochloraz was at a higher frequency in O. acuformis populations. The relative abundance of the two eyespot species was influenced by their differential levels of fungicide sensitivity, with the ratio increasing toward the species with the highest level of resistance to the prevailing fungicide. [source] Quantitative analysis of the secretome of TGF-, signaling-deficient mammary fibroblastsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 13 2010Baogang J. Xu Abstract Transforming growth factor , (TGF-,) is a master regulator of autocrine and paracrine signaling pathways between a tumor and its microenvironment. Decreased expression of TGF-, type II receptor (T,RII) in stromal cells is associated with increased tumor metastasis and shorter patient survival. In this study, SILAC quantitative proteomics was used to identify differentially externalized proteins in the conditioned media from the mammary fibroblasts with or without intact T,RII. Over 1000 proteins were identified and their relative differential levels were quantified. Immunoassays were used to further validate identification and quantification of the proteomic results. Differential expression was detected for various extracellular proteins, including proteases and their inhibitors, growth factors, cytokines, and extracellular matrix proteins. CXCL10, a cytokine found to be up-regulated in the T,RII knockout mammary fibroblasts, is shown to directly stimulate breast tumor cell proliferation and migration. Overall, this study revealed hundreds of specific extracellular protein changes modulated by deletion of T,RII in mammary fibroblasts, which may play important roles in the tumor microenvironment. These results warrant further investigation into the effects of inhibiting the TGF-, signaling pathway in fibroblasts because systemic inhibition of TGF-, signaling pathways is being considered as a potential cancer therapy. [source] Monkeys and apes: Are their cognitive skills really so different?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Federica Amici Abstract Differences in cognitive skills across taxa, and between monkeys and apes in particular, have been explained by different hypotheses, although these often are not supported by systematic interspecific comparisons. Here, we directly compared the cognitive performance of the four great apes and three monkey species (spider monkeys, capuchin monkeys, and long-tailed macaques), differing in their phylogenetic-relatedness and socioecology. We tested subjects on their ability to remember object locations (memory task), track object displacements (transposition task), and obtain out-of-reach rewards (support task). Our results showed no support for an overall clear-cut distinction in cognitive skills between monkeys and apes as species performance varied substantially across tasks. Although we found differences in performance at tracking object displacements between monkeys and apes, interspecific differences in the other two tasks were better explained in terms of differential socioecology, especially differential levels of fission,fusion dynamics. A cluster analysis using mean scores of each condition of the three tasks for each species suggested that the only dichotomy might be between members of the genus Pan and the rest of the tested species. These findings evidence the importance of using multiple tasks across multiple species in a comparative perspective to test different explanations for the enhancement of specific cognitive skills. Am J Phys Anthropol 143:188,197, 2010. © 2010 Wiley-Liss, Inc. [source] ORIGINAL ARTICLE: Effects of Peritoneal Fluid from Endometriosis Patients on Interferon-,-Induced Protein-10 (CXCL10) and Interleukin-8 (CXCL8) Released by Neutrophils and CD4+ T CellsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2009Ji-Yeon Kim Problem, Intraperitoneal immuno-inflammatory changes may be associated with the pathogenesis of endometriosis. We evaluated the effects of peritoneal fluid obtained from patients with endometriosis (ePF) on the release of interferon-,-induced protein-10 (IP-10/CXCL10) and interleukin-8 (IL-8/CXCL8) by neutrophils, CD4+ T cells, and monocytes. Method of study, Neutrophils, CD4+ T cells, and monocytes were cultured with ePF and the chemokine levels in the supernatants were then measured using enzyme-linked immunosorbent assay. Results, The addition of ePF to cultures of CD4+ T cells led to a significant increase in the release of IP-10 when compared with control PF without endometriosis (cPF). There was a positive correlation between the levels of IL-8 and IP-10 in ePF (R = 0.89, P = 0.041), but not between the levels of IP-10 and IL-8 released by neutrophils, CD4+ T cells, and monocytes. The levels of IP-10 in ePF were positively correlated with the release of IP-10 by ePF-treated neutrophils (R = 0.89, P < 0.001), CD4+ T cells (R = 0.93, P < 0.001), and monocytes (R = 0.70, P = 0.01). Moreover, the addition of ePF significantly enhanced the interferon-,-induced release of IP-10 by nuetrophils and CD4+ T cells. Conclusion, These findings suggest that neutrophils and T cells release differential levels of IP-10 and IL-8 in response to stimulation with ePF, and that these cells are a major source of IP-10 in the PF of endometriosis patients. [source] | ||||||||||