Search results for "Activation"
showing 10 items of 2079 documents
Modulation of intracellular calcium concentrations and T cell activation by prickly pear polyphenols.
2004
Opuntia ficus indica (prickly pear) polyphenolic compounds (OFPC) triggered an increase in [Ca2+]i in human Jurkat T-cell lines. Furthermore, OFPC-induced rise in [Ca2+]i was significantly curtailed in calcium-free buffer (0% Ca2+) as compared to that in 100% Ca2+ medium. Preincubation of cells with tyrphostin A9, an inhibitor of Ca2+ release-activated Ca2+ (CRAC) channels, significantly diminished the OFPC-induced sustained response on the increases in [Ca2+]i. Lanthanum and nifedipine, the respective inhibitors of voltage-dependent and L-type calcium channels, failed to curtail significantly the OFPC-induced calcium response. As OFPC still stimulated increases in [Ca2+]i in 0% Ca2+ medium…
The designer cytokine hyper-interleukin-6 is a potent activator of STAT3-dependent gene transcription in vivo and in vitro.
1999
Interleukin-6 (IL-6) triggers pivotal pathways in vivo. The designer protein hyper-IL-6 (H-IL-6) fuses the soluble IL-6 receptor (sIL-6R) through an intermediate linker with IL-6. The intracellular pathways that are triggered by H-IL-6 are not defined yet. Therefore, we studied the molecular mechanisms leading to H-IL-6-dependent gene activation. H-IL-6 stimulates haptoglobin mRNA expression in HepG2 cells, which is transcriptionally mediated as assessed by run-off experiments. The increase in haptoglobin gene transcription correlates with higher nuclear translocation of tyrosine-phosphorylated STAT3 and its DNA binding. As H-IL-6 stimulates STAT3-dependent gene transcription, we compared t…
A comparative thermogravimetric study of waterlogged archaeological and sound woods
2010
Waterlogged archaeological woods Pinus pinaster and Fagus sylvatica L. were analyzed by using TG technique. Degradation processes ascribable to the holocellulose decay were evidenced at nearly the same temperature for sound and archaeological samples. The residual matters at 600 and 900 °C of the sound woods are much lower than those of archaeological waterlogged woods in agreement with the presence of inorganic materials encapsulated during the burial into the marine environment. It was proposed a new protocol to rapidly calculate the maximum water content parameter, which is related to the wood degradation state. TG experiments at variable heating rates were performed to obtain kinetic pa…
Study of the ZnO crystal growth by vapour transport methods
2004
Abstract The crystal growth of ZnO by vapour transport is classically made with the assistance of additional species that produce a gaseous mixture, the role of which remains often uncertain in the transport and growth process. Initially, in order to study the mass transport process, a numerical simulation is made to analyse which are the requirements to have an effective transport. As the pressure of each gaseous species is generally unknown, the numerical study has been performed for different total pressures. It is found that, if congruent and equilibrium conditions are assumed at the sublimation and crystallisation interfaces, effective growth conditions can only be attained for a narro…
Adsorption of m-Xylene on Prehydrated Zeolite BaX: Correlation between Temperature-Programmed Desorption and Low-Temperature Neutron Powder Diffract…
1999
Adsorption of m-xylene on partially hydrated zeolite BaX is studied by thermogravimetry, mass spectrometry, temperature-programmed desorption and neutron diffraction for different m-xylene loadings of the zeolite. Macroscopic and microscopic measurements, for both molecules, were correlated and relationships were found between the crystallographic positions of the adsorbed molecules on the zeolite and macroscopic properties such as the number and the area of the peaks in the desorption spectra for m-xylene or water. The influence of water molecules on the adsorption phenomenon of m-xylene on BaX zeolite was characterized. In particular, it was shown that the increase of the filling of the p…
Lifetime predictions of non-ionic and ionic biopolymers: kinetic studies by non-isothermal thermogravimetric analysis
2021
AbstractIn this paper, films based on sustainable polymers with variable charge have been investigated by non-isothermal thermogravimetry in order to predict their lifetime, which is a key parameter for their potential use in numerous technological and biomedical applications. Specifically, chitosan has been selected as positively charged biopolymer, while alginate has been chosen as negatively charged biopolymer. Among non-ionic polymers, methylcellulose has been investigated. Thermogravimetric measurements at variable heating rates (5, 10, 15 and 20 °C min−1) have been performed for all the polymers to study their degradation kinetics by using isoconversional procedures combined with ‘Mas…
JNK phosphorylation relieves HDAC3-dependent suppression of the transcriptional activity of c-Jun
2003
The AP-1 transcription factor c-Jun is a prototypical nuclear effector of the JNK signal transduction pathway. The integrity of JNK phosphorylation sites at serines 63/73 and at threonines 91/93 in c-Jun is essential for signal-dependent target gene activation. We show that c-Jun phosphorylation mediates dissociation of an inhibitory complex, which is associated with histone deacetylase 3 (HDAC3). The subsequent events that ultimately cause increased mRNA synthesis are independent of c-Jun phosphorylation and its interaction with JNK. These findings provide an 'activation by de-repression' model as an explanation for the stimulatory function of JNK on c-Jun.
Detoxifying antitumoral drugs via nanoconjugation: the case of gold nanoparticles and cisplatin
2021
Nanoparticles (NPs) have emerged as a potential tool to improve cancer treatment. Among the proposed uses in imaging and therapy, their use as a drug delivery scaffold has been extensively highlighted. However, there are still some controversial points which need a deeper understanding before clinical application can occur. Here the use of gold nanoparticles (AuNPs) to detoxify the antitumoral agent cisplatin, linked to a nanoparticle via a pH-sensitive coordination bond for endosomal release, is presented. The NP conjugate design has important effects on pharmacokinetics, conjugate evolution and biodistribution and results in an absence of observed toxicity. Besides, AuNPs present unique o…
Cardiovascular effects of air pollution
2017
Air pollution is composed of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide and ozone. PM is classified according to size into coarse particles (PM 10), fine particles (PM 2.5) and ultrafine particles. We aim to provide an original review of the scientific evidence from epidemiological and experimental studies examining the cardiovascular effects of outdoor air pollution. Pooled epidemiological studies reported that a 10 μg/m 3 increase in long-term exposure to PM 2.5 was associated with an 11% increase in cardiovascular mortality. Increased cardiovascular mortality was also related to long-term and short-term exposure to nitrogen dioxide. Exposure to air pollution…
pRb suppresses camptothecin-induced apoptosis in human osteosarcoma Saos-2 cells by inhibiting c-Jun N-terminal kinase
2001
AbstractThis paper studies the cytotoxic effect induced by the topoisomerase I inhibitor camptothecin in human osteosarcoma Saos-2 cells, which lack p53 and contain a non-functional form of the product of the retinoblastoma gene, pRb. Cytotoxicity induced by camptothecin was dose- and time-dependent; the treatment with 100 nM camptothecin reduced cell viability by 50% at 32 h and by 75% at 72 h of exposure. The cytotoxic effect was caused by apoptosis, as ascertained by morphological evidence, acridine orange-ethidium bromide staining and flow cytometric analysis. Apoptosis was accompanied by both the activation of caspase-3 and the fragmentation of poly(ADP-ribose) polymerase. Treatment wi…