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Long-term Protection (long-term + protection)
Selected AbstractsBrief exposure to NMDA produces long-term protection of cerebellar granule cells from apoptosisEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2005Xavier Xifro Abstract Cerebellar granule cells (CGCs) require excitatory inputs to survive during their postnatal migration from the external to the internal granule cell layers. The lack of innervation of mossy fibres induces CGC death by apoptosis. In vitro, CGCs die by apoptosis in the presence of physiological concentrations of KCl (5 mm or K5) but they survive in the presence of depolarizing concentrations of KCl (25 mm or K25) or N -methyl- d -aspartate (NMDA) by a mechanism dependent on calcium influx. The addition of NMDA or K25, for only 24 h, to immature CGCs cultures [2 days in vitro (DIV)] was able to produce a remarkable and long-term protection until 8 DIV. Moreover, our data show that NMDA and K25-mediated long-lasting protection was related to an inhibition of caspase-3 activity. By using different protein kinase inhibitors, we have shown that the inhibition of caspase-3 activation by NMDA was dependent on the activation of tyrosine kinases and phosphatidylinositol 3-kinase (PI3-kinase). Moreover, an impairment in NMDA-mediated neuroprotection and caspase-3 inhibition was observed when the action of brain-derived neurotrophic factor (BDNF) was blocked. By contrast, K25-mediated neuroprotection was BDNF-independent and was mediated by a mitogen-activated protein kinase- and PI3-kinase-dependent inhibition of caspase-3. [source] Non-malignant clonal expansions of CD8+ memory T cells in aged individualsIMMUNOLOGICAL REVIEWS, Issue 1 2005Eric T. Clambey Summary:, CD8+ T cells provide a major line of defense against intracellular pathogens. Upon encounter with antigen, CD8+ T cells go through three distinct phases involving proliferation, contraction, and differentiation to become eventually long-lived CD8+ memory T cells. CD8+ memory T cells provide long-term protection against infection by intracellular pathogens. CD8+ memory T-cell proliferation and survival are regulated by many factors, including cytokines, and CD8+ memory T cells are stably maintained over a period of months to years. In aged humans and mice, however, there are significant alterations to the CD8+ memory T-cell compartment with frequent development of monoclonal expansions of CD8+ memory T cells in healthy individuals. Interestingly, CD8+ clonal expansions are not malignant and do not progress to lymphomas, suggesting that these cells must still be under certain constraints. In this review, we discuss our current understanding of factors that contribute to and regulate these CD8+ clonal expansions as well as the impact of CD8+ clonal expansions on immune function of the aged. In addition, we discuss similarities and differences between CD8+ clonal expansions observed in humans and mice, and we postulate that CD8+ clonal expansions represent a spectrum of biological outcomes ranging from antigen-driven to antigen-independent phenomena. [source] Gene expression profiling of gut mucosa and mesenteric lymph nodes in simian immunodeficiency virus-infected macaques with divergent disease courseJOURNAL OF MEDICAL PRIMATOLOGY, Issue 4-5 2006M.D. George Abstract Background, Although the majority of drug-naïve HIV-infected patients develop acquired immunodeficiency syndrome (AIDS), a small percentage remains asymptomatic without therapeutic intervention. Methods, We have utilized the simian immunodeficiency virus (SIV)-infected rhesus macaque model to gain insights into the molecular mechanisms of long-term protection against simian AIDS. Results, Chronically SIV-infected macaques with disease progression had high viral loads and CD4+ T-cell depletion in mucosal tissue and peripheral blood. These animals displayed pathologic changes in gut-associated lymphoid tissue (GALT) and mesenteric lymph node that coincided with increased expression of genes associated with interferon induction, inflammation and immune activation. In contrast, the animal with long-term asymptomatic infection suppressed viral replication and maintained CD4+ T cells in both GALT and peripheral blood while decreasing expression of genes involved in inflammation and immune activation. Conclusions, Our findings suggest that reduced immune activation and effective repair and regeneration of mucosal tissues correlate with long-term survival in SIV-infected macaques. [source] Persistence and efficacy of two diatomaceous earth formulations and a mixture of diatomaceous earth with natural pyrethrum against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on wheat and maizePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 5 2006Basileios J Vayias Abstract Laboratory tests were conducted to assess the insecticidal and residual effects of three diatomaceous earth (DE) formulations, Insecto®, PyriSec® and SilicoSec®, against Tribolium confusum Jacquelin du Val on wheat and maize. Quantities of wheat and maize were treated with the above formulations at 500, 1000 and 1500 mg kg,1 and stored at 25 °C and 55% relative humidity (RH). Samples were taken on the day of storage and every 30 days until completion of a 360 day period of storage. Adults of T. confusum were exposed to these samples at 25 °C and 55% RH and the mortality was measured after 24 and 48 h and 7 and 14 days of exposure. Adult mortality was higher on wheat than on maize. At the beginning of the storage period, mortalities after 14 day exposure on maize treated with the highest rate were 60, 63 and 81% for Insecto®, PyriSec® and SilicoSec® respectively, while on wheat the mortality was 100% for all DEs. On the same commodities 360 days after treatment the respective mortality figures for wheat were 99, 98 and 100%, while in the case of maize they did not exceed 7%. Generally, mortality at exposures ,48 h decreased with increasing storage time. Furthermore, although mortality on wheat increased with dose, the increase in DE dose from 1000 to 1500 mg kg,1 resulted in only a small increase in mortality. Thus a DE treatment of 1000 mg kg,1 was shown to provide long-term protection of wheat against T. confusum, although higher DE application rates and exposure intervals are needed for a satisfactory level of protection of maize against this pest. Copyright © 2006 Society of Chemical Industry [source] Time course of serum inhibitory activity for facilitated allergen,IgE binding during bee venom immunotherapy in childrenCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2009E-M Varga Summary Background Immunotherapy for bee venom allergy is effective and provides long-term protection. Venom-specific IgG4 levels are increased but with no correlation with clinical improvement. Following grass pollen immunotherapy, elevation of antigen-specific IgG4 is accompanied by increases in IgG-dependent serum inhibitory activity for IgE-facilitated binding of allergen,IgE complexes to B cells. As this ,functional' assay of inhibitory antibodies may be more predictive of clinical efficacy, we investigated the time course of serum inhibitory activity for IgE-facilitated antigen binding during venom immunotherapy (VIT) in children and following 2 years of VIT withdrawal. Methods Ten bee venom-allergic children (mean age: 9.3 years; m/f, 7/3) with moderate to severe allergic reactions to bee stings received VIT. A separate group of seven children (mean age: 14 years; m/f, 5/2) were investigated 2 years after VIT withdrawal. Ten age- and gender-matched children served as non-allergic controls. Allergen-specific serum IgG4 and IgE levels were measured by ELISA at baseline, after 2 years of VIT and 2 years after VIT withdrawal. Serum inhibitory activity was assessed using the facilitated-allergen binding (FAB) assay. Results Sera obtained during VIT significantly inhibited allergen,IgE binding to B-cells (pre-treatment=104±23%; 2 years=46±15%; P<0.001) when compared with sera obtained after treatment withdrawal and sera from normal controls. In parallel to FAB inhibition during VIT, significantly higher IgG4 levels were noted after immunotherapy (pre-treatment=8.6±2.3 AU; 2 years=26.7±3.5 AU; P<0.001) compared with those observed after withdrawal and in the controls. In contrast, progressively lower IgE concentrations were observed compared with pre-treatment (44±7 AU) in sera obtained after 2 years of VIT (25±5 AU; P<0.01) and 2 years following the withdrawal of VIT (10±3 AU; P<0.05). Conclusions In contrast to grass pollen immunotherapy, the persistent decline in venom-specific IgE levels, rather than serum inhibitory activity for FAB, may be more relevant for long-term clinical efficacy of VIT. [source] | ||||||||||