The discovery of drugs for the treatment of inflammatory allergic diseases such as, asthma, allergic rhinitis, and sinusitis is a very important subject in human health. Gallic acid (3,4,5-trihydroxybenzoic acid), a polyphenyl natural products from gallnut and green tea, is known to have anti-oxidant, anti-inflammatory, anti-microbial, and radical scavenging activities. The aim of the present study was to elucidate whether gallic acid modulates the inflammatory allergic reaction and to study its possible mechanisms of action. Gallic acid attenuated compound 48/80- or immunoglobulin E (IgE)-induced histamine release from mast cells. The inhibitory effect of gallic acid on the histamine release was mediated by the modulation of cAMP and intracellular calcium. Gallic acid decreased the phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated pro-inflammatory cytokine gene expression and production such as TNF-alpha and IL-6 in human mast cells. The inhibitory effect of gallic acid on the pro-inflammatory cytokine was nuclear factor-kappaB and p38 mitogen-activated protein kinase dependent. In addition, gallic acid inhibited compound 48/80-induced systemic allergic reaction and IgE-mediated local allergic reaction. The inhibitory activity of gallic acid on the allergic reaction and histamine release was found to be similar with disodium cromoglycate. Our findings provide evidence that gallic acid inhibits mast cell-derived inflammatory allergic reactions by blocking histamine release and pro-inflammatory cytokine expression, and suggest the mechanisms of action. Furthermore, in vivo and in vitro anti-allergic effect of gallic acid suggests a possible therapeutic application of this agent in inflammatory allergic diseases.
We have finished the construction of an automated tool for step and flash imprint lithography. The tool was constructed to allow defect studies by making multiple imprints on a 200 mm wafer. The imprint templates for this study were treated with a low surface energy, self-assembled monolayer to ensure selective release at the template-etch barrier interface. This surface treatment is very durable and survives repeated imprints and multiple aggressive physical and chemical cleanings. The imprint and release forces were measured for a number of successive imprints, and did not change significantly. The process appears to be ''self-cleaning.'' Contamination on the template is entrained in the polymerizing liquid, and the number of defects is reduced with repeated imprints.
Oscillatory activity in excess of several hundred hertz has been observed in somatosensory evoked potentials (SEP) recorded in both humans and animals and is attracting increasing interest regarding its role in brain function. Currently, however, little is known about the cellular events underlying these oscillations. The present study employed simultaneous in-vivo intracellular and epipial field-potential recording to investigate the cellular correlates of fast oscillations in rat somatosensory cortex evoked by vibrissa stimulation. Two distinct types of fast oscillations were observed, here termed "fast oscillations" (FO) (200-400 Hz) and "very fast oscillations" (VFO) (400-600 Hz). FO coincided with the earliest slow-wave components of the SEP whereas VFO typically were later and of smaller amplitude. Regular spiking (RS) cells exhibited vibrissa-evoked responses associated with one or both types of fast oscillations and consisted of combinations of spike and/or subthreshold events that, when superimposed across trials, clustered at latencies separated by successive cycles of FO or VFO activity, or a combination of both. Fast spiking (FS) cells responded to vibrissae stimulation with bursts of action potentials that closely approximated the periodicity of the surface VFO. No cells were encountered that produced action potential bursts related to FO activity in an analogous fashion. We propose that fast oscillations define preferred latencies for action potential generation in cortical RS cells, with VFO generated by inhibitory interneurons and FO reflecting both sequential and recurrent activity of stations in the cortical lamina.
Submicron patterning of 1 in. diameter curved surfaces with a 46 mm radius of curvature has been demonstrated with step and flash imprint lithography ͑SFIL͒ using templates patterned by ion beam proximity printing ͑IBP͒. Concave and convex spherical quartz templates were coated with 700-nm-thick poly͑methylmethacrylate͒ ͑PMMA͒ and patterned by step-and-repeat IBP. The developed resist features were etched into the quartz template and the remaining PMMA stripped. During SFIL, a low viscosity, photopolymerizable formulation containing organosilicon precursors was introduced into the gap between the etched template and a substrate coated with an organic transfer layer and exposed to ultraviolet illumination. The smallest features on the templates were faithfully replicated in the silylated layer.
In the present study, we investigated the neurotoxicity of bisphenol A [BPA; 2,2-bis-(4 hydroxyphenyl) propane] and the underlying mechanisms of action in mouse hippocampal HT-22 cells. BPA, known to be a xenoestrogen, is used in the production of water bottles, cans, and teeth suture materials. BPA-treated HT-22 cells showed lower cell viability than did controls at concentrations of BPA over 100 microM. BPA induced apoptotic cell death as indicated by staining with Hoechst 33258, costaining with Annexin V/propidium iodide, and activation of caspase 3. BPA regulated the generation of reactive oxygen species (ROS) by increasing intracellular calcium. BPA activated phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), and nuclear translocation of nuclear factor (NF)-kappaB. Pretreatment with specific inhibitors for calcium, ROS, ERK, and JNK decreased BPA-induced cell death; however, inhibitor for NF-kappaB increased BPA-induced cell death. The results suggest that calcium, ROS, ERK, and JNK are involved in BPA-induced apoptotic cell death in HT-22 cells. In contrast, an NF-kappaB cascade was activated for survival signaling after BPA treatment.
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