Search results for "Smut"
showing 10 items of 493 documents
Perspectives for CNO neutrino detection in Borexino
2018
International audience; Borexino measured with unprecedented accuracy the fluxes of solar neutrinos emitted at all the steps of the pp fusion chain. Still missing is the measurement of the flux of neutrinos produced in the CNO cycle. A positive measurement of the CNO neutrino flux is of fundamental importance for understanding the evolution of stars and addressing the unresolved controversy on the solar abundances. The measurement of the CNO neutrino flux in Borexino is challenging because of the low intensity of this component (CNO cycle accounts for about 1% of the energy emitted by Sun), the lack of prominent spectral features and the presence of background sources. The main background c…
Cathodic reduction of CO2 to formic acid: Effect of the nature of the cathode for pressurized systems
2023
Electrochemical conversion of CO2 into formic acid (FA) in an aqueous electrolyte is considered a promising strategy to valorise waste-CO2. Some studies, mainly performed using Sn cathodes, have shown that the performance of the process can be strongly improved using pressurized systems. On the other hand, other studies, usually carried out in non-pressurized systems, have indicated that the nature of the cathode can strongly affect the process. Hence, in this work, we have investigated the coupled effect of nature of the cathode and CO2 pressure (PCO2 ) on the electrochemical conversion of CO2 to FA. Four electrodes (Sn, Sn/C-NP, Bi, Bi/C-NP) have been used as model cathodes. The results o…
Natural polyphenols facilitate elimination of HT-29 colorectal cancer xenografts by chemoradiotherapy: a Bcl-2- and superoxide dismutase 2-dependent …
2008
AbstractColorectal cancer is one of the most common malignancies worldwide. The treatment of advanced colorectal cancer with chemotherapy and radiation has two major problems: development of tumor resistance to therapy and nonspecific toxicity towards normal tissues. Different plant-derived polyphenols show anticancer properties and are pharmacologically safe. In vitro growth of human HT-29 colorectal cancer cells is inhibited (∼56%) by bioavailable concentrations of trans-pterostilbene (trans-3,5-dimethoxy-4′-hydroxystilbene; t-PTER) and quercetin (3,3′,4′,5,6-pentahydroxyflavone; QUER), two structurally related and naturally occurring small polyphenols. I.v. administration of t-PTER and Q…
Antioxidant defenses in a B16 melanoma line resistant to doxorubicin: an in vivo study.
1991
A B16 melanoma line was repeatedly transplanted subcutaneously in C57BL/6 mice. On day 4 after every transplant, the animals were treated with doxorubicin (DXR), 10 mg/kg i.p. The aim of the work was to develop an in-vivo model of resistance to the antiblastic in order to analyze some possible mechanistic aspects of the process in the course of time. After 16 transplants and treatments the melanoma completely lost its sensitivity to the antiproliferative effects of maximal tolerated doses of DXR and showed over-expression of P-glycoprotein. Compared to the parental line, the in vitro resistance index was 4.6. After 27 transplants and treatments the melanoma did not increase its in vitro res…
Role of glutathione in the induction of apoptosis and c-fos and c-jun mRNAs by oxidative stress in tumor cells.
2003
We have used two tumor cell clones (B9 and G2), derived from the methylcholanthrene-induced murine fibrosarcoma GR9 and normal BALB/c3T3 fibroblasts, to study the ability of t-BOOH derived reactive oxygen radicals to induce oxidative stress, apoptosis and c-fos and c-jun mRNA transcription. These clones differ in terms of their major histocompatibility complex (MHC) (H-2) class I genes expression, their tumor induction and metastatic potential and their reduced glutathione (GSH) levels. Incubation of both cell clones in the presence of t-BOOH results in the increase of 8-oxo-2'-deoxyguanosine (8-oxo-dG) and malondialdehyde and the decrease of GSH. The xenobiotic also induces the transcripti…
Spontaneous mutagenesis in Csb(m/m)Ogg1⁻(/)⁻ mice is attenuated by dietary resveratrol.
2010
Oxidative DNA modifications such as 7,8-dihydro-8-oxoguanine (8-oxoG) are generated endogenously in apparently all living cells. The defect of the repair of 8-oxoG in Csb m/m Ogg1 ―/― mice results in elevated basal levels of these lesions and increased frequencies of spontaneous mutations, which initiate tumorigenesis in the liver if cell proliferation is stimulated. Here, we describe that the phytoalexin resveratrol, applied either for 7 days per gavage (100 mg/kg body wt) or for 3―9 months in the diet (0.04% ad libitum), reduces the endogenous oxidative DNA base damage in the livers of the Csb m/m Ogg1 ―/― mice by 20―30% (P < 0.01). A small but consistent effect is also observed in the wi…
Production of superoxide by human malignant melanoma cells.
1998
Metastasis is a complicated multi-step process involving interactions between tumour cells, the extracellular matrix and the vessel walls. Experimental observations suggest that leucocyte migration and function could be a suitable model in order to understand tumour cell dissemination. In the present report we show and quantify the production of free radicals by human malignant melanoma cells (St-ml12) by means of a spectrophotometrical method, using an enzyme immunoassay reader. Endothelial cells and activated polymorphonuclear leucocytes were used as controls. Melanoma cells without stimulants produced large amounts of superoxide anion at an increasing rate in relation to time, which coul…
The oxygen radicals involved in the toxicity induced by parthenolide in MDA-MB-231 cells
2014
It has been shown that the sesquiterpene lactone parthenolide lowers the viability of MDA-MB-231 breast cancer cells, in correlation with oxidative stress. The present report examined the different radical species produced during parthenolide treatment and their possible role in the toxicity caused by the drug. Time course experiments showed that in the first phase of treatment (0-8 h), and in particular in the first 3 h, parthenolide induced dichlorofluorescein (DCF) signal in a large percentage of cells, while dihydroethidium (DHE) signal was not stimulated. Since the effect on DCF signal was suppressed by apocynin and diphenyleneiodonium (DPI), two inhibitors of NADPH oxidase (NOX), we s…
WIN 55,212-2, agonist of cannabinoid receptors, prevents amyloid β1-42 effects on astrocytes in primary culture
2015
Alzheimer's disease (AD), a neurodegenerative illness involving synaptic dysfunction with extracellular accumulation of Aβ1-42 toxic peptide, glial activation, inflammatory response and oxidative stress, can lead to neuronal death. Endogenous cannabinoid system is implicated in physiological and physiopathological events in central nervous system (CNS), and changes in this system are related to many human diseases, including AD. However, studies on the effects of cannabinoids on astrocytes functions are scarce. In primary cultured astrocytes we studied cellular viability using MTT assay. Inflammatory and oxidative stress mediators were determined by ELISA and Western-blot techniques both in…
Heterodimer formation of wild-type and amyotrophic lateral sclerosis-causing mutant Cu/Zn-superoxide dismutase induces toxicity independent of protei…
2008
Recent studies provide evidence that wild-type Cu/Zn-superoxide dismutase (SOD1(hWT)) might be an important factor in mutant SOD1-mediated amyotrophic lateral sclerosis (ALS). In order to investigate its functional role in the pathogenesis of ALS, we designed fusion proteins of two SOD1 monomers linked by a polypeptide. We demonstrated that wild-type-like mutants, but not SOD1(G85R) homodimers, as well as mutant heterodimers including SOD1(G85R)-SOD1(hWT) display dismutase activity. Mutant homodimers showed an increased aggregation compared with the corresponding heterodimers in cell cultures and transgenic Caenorhabditis elegans, although SOD1(G85R) heterodimers are more toxic in functiona…