Search results for "Cytotoxic"
showing 10 items of 1673 documents
Friend retrovirus infection of myeloid dendritic cells impairs maturation, prolongs contact to naïve T cells, and favors expansion of regulatory T ce…
2007
AbstractRetroviruses have developed immunmodulatory mechanisms to avoid being attacked by the immune system. The mechanisms of this retrovirus-associated immune suppression are far from clarified. Dendritic cells (DCs) have been attributed a decisive role in these pathogenic processes. We have used the Friend retrovirus (FV) mouse model in order to acquire further knowledge about the role of infection of DCs in virus-induced immunosuppression. About 20% of the myeloid DCs that were generated from the bone marrow of FV-infected mice carried FV proteins. The infection was productive, and infected DCs transmitted the virus in cell culture and in vivo. FV infection of DCs led to a defect in DC …
Loss of Nrf2 in bone marrow-derived macrophages impairs antigen-driven CD8+ T cell function by limiting GSH and Cys availability
2015
NF-E2-related factor 2 (Nrf2), known to protect against reactive oxygen species, has recently been reported to resolve acute inflammatory responses in activated macrophages. Consequently, disruption of Nrf2 promotes a proinflammatory macrophage phenotype. In the current study, we addressed the impact of this macrophage phenotype on CD8(+) T cell activation by using an antigen-driven coculture model consisting of Nrf2(-/-) and Nrf2(+/+) bone marrow-derived macrophages (BMDMΦ) and transgenic OT-1 CD8(+) T cells. OT-1 CD8(+) T cells encode a T cell receptor that specifically recognizes MHC class I-presented ovalbumin OVA(257-264) peptide, thereby causing a downstream T cell activation. Interes…
2-(2,6-Dihalophenyl)-3-(pyrimidin-2-yl)-1,3-thiazolidin-4-ones as non-nucleoside HIV-1 reverse transcriptase inhibitors.
2004
Several 1,3-thiazolidin-4-ones bearing a 2,6-dihalophenyl group at C-2 and a substituted pyrimidin-2-yl ring at the N-3 were synthesised and evaluated as anti-HIV agents. The results of the in vitro tests showed that some of them were highly effective inhibitors of human immunodeficiency virus type-1 (HIV-1) replication at 10–40 nM concentrations with minimal cytotoxicity. Structure–activity relationship studies revealed that the nature of the substituents at the 2 and 3 positions of the thiazolidinone nucleus had a significant impact on the in vitro anti-HIV activity of this class of potent antiretroviral agents. The compounds had significantly reduced activity against the characteristic N…
Elaboration of functionalized nanoparticles : applications as MRI contrast agent
2010
Spinel structured iron oxide nanoparticles open the way of biomedical applications of nanomaterials.Superparamagnetic properties of ten nanometer size crystallites permit to use them in diagnosis such as Magnetic Resonance Imaging (MRI).The aim of this work was to synthesize colloidal suspension of magnetite or maghemite (called USPIO for Ultrasmall SuperParamagnetic Iron Oxide) stable in physiological conditions (pH = 7.4 and [NaCl] = 0.15M).By classical co-precipitation method, UPSIO were synthesized with a mean crystallite size of 8 nm, with a specific surface area of 110 m².g-1 and an aggregate size of 20 nm. To stabilize these nano-objects, two ways were investigated. Electrostatic age…
Lipid nanocarriers containing esters prodrugs of Flurbiprofen. Preparation, physical-chemical characterization and biological studies.
2013
In this paper, the preparation, chemical-physical, technological and in vitro characterization of nanostructured lipid carriers (NLC) carrying R-flurbiprofen ester prodrugs, were analyzed for a potential pharmaceutical application. R-flurbiprofen was chosen as a model drug because it has been found to play an effective role in counteracting secretases involved in neurodegenerative diseases, although it does not cross the Blood Brain Barrier (BBB). In this study, two R-flurbiprofen ester prodrugs (ethyl and hexyl) were successfully synthesized and entrapped into non-pegylated and pegylated NLC. The obtained systems showed average diameters in the colloidal size range, negative zeta potential…
Induction of ambuic acid derivatives by the endophytic fungus Pestalotiopsis lespedezae through an OSMAC approach
2021
Abstract Ten new ambuic acid derivatives, pestallic acids H–Q including one new iodinated natural product along with two known compounds, ambuic acid and ambuic acid 18-acetate, were obtained through fermentation of the endophytic fungus Pestalotiopsis lespedezae on solid rice medium with 3.5% NaI. Pestallic acids H–Q were undetectable in cultures of the fungus grown on solid rice medium lacking NaI or in those where NaI had been replaced by NaCl or NaBr. The structures of the new metabolites were established on basis of 1D/2D NMR and HRESIMS data. Their absolute configurations were determined by Mosher’s method and TDDFT-ECD calculations. The compounds failed to show antibacterial activity…
T-2 toxin and its metabolites: Characterization, cytotoxic mechanisms and adaptive cellular response in human hepatocarcinoma (HepG2) cells
2020
Abstract The T-2 toxin (T-2) is a type A trichothecene produced by Fusarium species, and the most cytotoxic mycotoxin of the group. A study was made to determine T-2 cytotoxicity in human hepatocarcinoma (HepG2) cells; evaluate whether there is an adaptive response of HepG2 cells exposed to low concentrations of T-2; identify the T-2 metabolites by LC-Q-TOF MS; and determine whether T-2 disrupts cell proliferation in HepG2 cells. The IC50 values obtained ranged from 61.9 ± 2.4 nM to 70.7 ± 7.4 nM. No adaptive response was observed. There was no evidence of extra- or intracellular accumulation of T-2 after 24 h of exposure as determined by LC-Q-TOF MS. However, some T-2 metabolites such as H…
Protective effect of antioxidants contained in milk-based fruit beverages against sterol oxidation products
2017
Abstract Sterol oxidation products (SOPs) have shown cytotoxic effect in human intestinal cells; however, their effect within a food matrix has not been assayed yet. This study evaluated the possible cytotoxic effect of SOPs within bioaccessible fractions (BFs) of two milk-based fruit beverages with (BFA)/without (BFB) plant sterols in differentiated Caco-2 cells and if the BFs counteracted the cytotoxic effect induced by COPs mixture (30 and 60 μM). BFs did not evoke cytotoxic effect in any of the tests carried out and they protected against the loss of intestinal cohesion, mitochondrial depolarization and necrosis induced by COPs mixture. Moreover, BFB sample protected from cell cycle arr…
Induction of Neuronal Differentiation in Neurosphere Stem Cells by Ellagic Acid Derivatives
2009
A bioassay-guided fractionation of methanol extracts of stem barks, combined with screening based on Epidermal Growth Factor (EGF)-responsive neural stem cells (erNSCs) differentiation assay, has been used. This study resulted in the isolation of 3,3′-di- O-methylellagic acid 1, 3,3′-di- O-methyl ellagic acid-4- O-β-D-xylopyranoside 2, ellagic acid 3, and arjunolic acid 4. Among them, compounds 1 and 2 exhibit potent induction of neuronal differentiation in neurosphere stem cells with no cytotoxic effect. These results indicate that compounds 1 and 2 may be useful as pharmacological agents for the treatment of neurodegenerative diseases. These compounds may account, for the use of T. super…
Uridine uptake inhibition as a cytotoxicity test for a human hepatoma cell line (HepG2 cells): comparison with the neutral red assay
2001
International audience; This study describes a sensitive microassay for measuring cytotoxicity based on the degree of inhibition of RNA synthesis in HepG2 cells. RNA synthesis is measured by the kinetic uptake of radiolabeled uridine. A large number of compounds were tested in a wide range of concentrations. The concentration required to induce 50% inhibition of HepG2 uridine uptake rates (IC50) was determined for each compound and used to rank its potency. These IC50s were compared with IC50s measured with the neutral red assay. 2-acetylaminofluorene, benzo[a]pyrene and methylnitrosourea were not cytotoxic in the neutral red assay. Uridine uptake was always inhibited at lower concentrations…