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Exogenous Stimuli (exogenous + stimulus)
Selected AbstractsAgricultural Growth and Inter-Sectoral Linkages in a Developing EconomyJOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2000N. Gemmell Does growth in the manufacturing sector of an economy spillover to agriculture, or do sectors share similar growth rates only when they share some common exogenous stimuli? The limited number of investigations of this issue, for cross-sections of countries, have found some evidence in favour of spillovers, though the methodologies used cannot readily separate correlation from causation. Adapting the Feder (1982) model of sectoral externalities to a time-series context, we examine how far agricultural output in Malaysia has been affected by inter-sectoral spillovers. Our results suggest that expansion of manufacturing output, though associated with reduced agricultural output in the short-run, is associated with agricultural expansion over the long-run. Service output growth on the other hand seems to have been inimical to agricultural growth in both the short- and long-runs, while causality testing supports the case for spillovers rather than "common causes". Evidence on sectoral productivity is consistent with neoclassical arguments suggesting that the benefits of higher productivity in manufacturing tend to spill over to agriculture, encouraging productivity convergence. [source] Role of phospholipases A2 in growth-dependent changes in prostaglandin release from 3T6 fibroblastsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2001Teresa Sánchez Previously, we reported a growth-dependent change in prostaglandin production as a consequence of a marked growth-dependent alteration in arachidonic acid (AA) mobilization from phospholipids. Our present results show that fetal calf serum (FCS) and 4,-phorbol-12-myristate acetate (PMA) caused an enhancement of phospholipase A2 (PLA2) activity in the membrane fraction of non-confluent cells allowing PLA2 access to its substrate and the release of AA. Western blot analysis has shown that FCS and PMA increased secreted PLA2 (sPLA2) expression in non-confluent 3T6 fibroblast cultures. Moreover, FCS and PMA induced dithiothreitol-sensitive and bromoenol lactone-sensitive PLA2 activities in cytosol and membrane fraction. However, these stimuli did not modify significantly the PLA2 activity in both fractions when 3T6 fibroblasts reached a high cell density. This could be associated with the impairment of AA mobilization in these cell culture conditions. On the other hand, we observed that FCS and PMA induced the same prostaglandin H synthase-2 induction in non-confluent and confluent culture conditions. Moreover, the prostaglandin E2 levels reached in cell culture supernatants were independent of the degree of confluence when AA was added exogenously. These results suggest that the changes of intracellular distribution of PLA2 activity of sPLA2 and iPLA2 stimulated by exogenous stimuli may be controlled by cell density conditions which constitute an important mechanism in the regulation of prostaglandin release.© 2001 Wiley-Liss, Inc. [source] Modulation of peroxisome proliferator-activated receptor-, activity by N -acetyl cysteine attenuates inhibition of oligodendrocyte development in lipopolysaccharide stimulated mixed glial culturesJOURNAL OF NEUROCHEMISTRY, Issue 3 2008Manjeet K. Paintlia Abstract Glial cells secrete proinflammatory mediators in the brain in response to exogenous stimuli such as infection and injury. Previously, we documented that systemic maternal lipopolysaccharide (LPS)-exposure at embryonic gestation day 18 causes oligodendrocyte (OL)-injury/hypomyelination in the developing brain which can be attenuated by N -acetyl cysteine (NAC; precursor of glutathione). The present study delineates the underlying mechanism of NAC-mediated attenuation of inhibition of OL development in LPS-stimulated mixed glial cultures. Factors released by LPS-stimulated mixed glial cultures inhibited OL development as shown by decrease in both proliferation 3bromo-deoxyuridine+/chondroitin sulfate proteoglycan,NG2+, hereafter BrdU+/NG+ and differentiation (O4+ and myelin basic protein+) of OL-progenitors. Correspondingly, an impairment of peroxisomal proliferation was shown by a decrease in the level of peroxisomal proteins in the developing OLs following exposure to LPS-conditioned media (LCM). Both NAC and WY14643, a peroxisome proliferator-activated receptor (PPAR)-, agonist attenuated these LCM-induced effects in OL-progenitors. Similar to WY14643, NAC attenuated LCM-induced inhibition of PPAR-, activity in developing OLs. Studies conducted with cytokines and diamide (a thiol-depleting agent) confirmed that cytokines are active agents in LCM which may be responsible for inhibition of OL development via peroxisomal dysfunction and induction of oxidative stress. These findings were further corroborated by similar treatment of developing OLs generated from PPAR-,(,/,) and wild-type mice or B12 oligodendroglial cells co-transfected with PPAR-, small interfering RNAs/pTK-PPREx3-Luc plasmids. Collectively, these data provide evidence that the modulation of PPAR-, activity, thus peroxisomal function by NAC attenuates LPS-induced glial factors-mediated inhibition of OL development suggesting new therapeutic interventions to prevent the devastating effects of maternal infections. [source] Reactivity to images in health and irritable bowel syndromeALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2010H. R. CARRUTHERS Summary Background, We have been using a medical artist to record and paint the images patients have of their irritable bowel syndrome (IBS) and have hypothesized that the reaction to such images might differ in health and IBS, which could have practical implications for future research. Aim, To examine reactivity to images in health and IBS. Methods, Twelve paintings of IBS were shown to 70 patients to determine the four most evocative images. The spontaneous response to these images and four ,non-IBS painful' and four neutral paintings was assessed in another 100 IBS patients and 100 controls. The prompted reaction in terms of whether an image evoked the notion of pain, bloating or discomfort and to what degree was also recorded. Results, Four images depicting bloating and pain scored the highest. These IBS images triggered significantly different reactivity between patients and controls in terms of their spontaneous and prompted responses. Even ,non-IBS painful' and neutral images resulted in exaggerated and frequently significantly different responses in patients than in controls. Conclusions, Visual hypersensitivity appears to be another manifestation of the tendency of IBS patients to react adversely to a variety of endogenous and exogenous stimuli. Identifying how individuals relate to different images might also give useful insights into understanding gastrointestinal symptoms. [source] Wnt signaling inside the nucleusCANCER SCIENCE, Issue 4 2008Miki Shitashige Accumulation of the ,-catenin protein and transactivation of a certain set of T-cell factor (TCF)-4 target genes by accumulated ,-catenin have been considered crucial in colorectal carcinogenesis. In the present review, we summarize nuclear proteins that interact with, and regulate, the ,-catenin and TCF and lymphoid enhancer factor (LEF) transcriptional complexes. Our recent series of proteomic studies has also revealed that various classes of nuclear proteins participate in the ,-catenin,TCF-4 complex and modulate its transcriptional activity. Furthermore, the protein composition of the TCF-4-containing nuclear complex is not fixed, but is regulated dynamically by endogenous programs associated with intestinal epithelial cell differentiation and exogenous stimuli. Restoration of the loss-of-function mutation of the adenomatous polyposis coli (APC) gene in colorectal cancer cells does not seem to be a realistic approach with currently available medical technologies, and only signaling molecules downstream of the APC gene product can be considered as targets of pharmacological intervention. Nuclear proteins associated with the ,-catenin,TCF-4 complex may include feasible targets for molecular therapy against colorectal cancer. Recently, an inhibitor of the interaction between CREB-binding protein and ,-catenin was shown to efficiently shut down the transcriptional activity of TCF-4 and induce apoptosis of colorectal cancer cells. We also summarize current strategies in the development of drugs against Wnt signaling. (Cancer Sci 2008; 99: 631,637) [source] Drinking a lot is good for dendritic cellsIMMUNOLOGY, Issue 4 2006Christopher C. Norbury Summary Macropinocytosis is the actin-dependent formation of large vesicles, which allow the internalization of large quantities of fluid-phase solute. In the majority of cells examined, an exogenous stimulus is required to induce the initiation of this endocytic pathway. However, dendritic cells are thought to constitutively macropinocytose large quantities of exogenous solute as part of their sentinel function. In this review we discuss the evidence that dendritic cells macropinocytose exogenous solute and subsequently present antigenic peptides derived from internalized material to T cells. In addition, we put these data into the context of immune surveillance in vivo. [source] | |||||||||||||