Search results for "Reactive"
showing 10 items of 1469 documents
Inhibition of in vitro macrophage-induced low density lipoprotein oxidation by thyroid compounds
2003
Oxidized low density lipoproteins (LDL) are highly suspected of initiating the atherosclerosis process. Thyroid hormones and structural analogues have been reported to protect LDL from lipid peroxidation induced by Cu2+ or the free radical generator 2,2'-azobis-'2-amidinopropane' dihydrochloride in vitro. We have examined the effects of thyroid compounds on macrophage-induced LDL oxidation. Human monocyte-derived macrophages (differentiated U937 cells) were incubated for 24 h with LDL and different concentrations (0-20 microM) of 3,5,3'-triiodo-l -thyronine (T3), 3,5,3',5'-tetraiodo-L-thyronine (T4), 3,3',5'-tri-iodo-l -thyronine (rT3), the T3 acetic derivative (3,5,3'-tri-iodothyroacetic a…
Gold Nanoparticles Supported on Nanoparticulate Ceria as a Powerful Agent against Intracellular Oxidative Stress
2012
Ceria-supported gold nanoparticles are prepared exhibiting peroxidase activity and acting as radical traps. Au/CeO2 shows a remarkable biocompatibility as demonstrated by measuring cellular viability, proliferation, and lack of apoptosis for two human cell lines (Hep3B and HeLa). The antioxidant activity of Au/CeO2 against reactive oxygen species (ROS) is demonstrated by studying the cellular behavior of Hep3B and HeLa in a model of cellular oxidative stress. It is determined that Au/CeO2 exhibits higher antioxidant activity than glutathione, the main cytosolic antioxidant compound, and its CeO2 carrier. Overall the result presented here shows the potential of implementing well-established …
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…
Does low concentration mycotoxin exposure induce toxicity in HepG2 cells through oxidative stress?
2020
The purpose of this study was to determine whether exposure to low concentrations of deoxynivalenol (DON), T-2 toxin (T-2) and patulin (PAT) in a human hepatocellular carcinoma cell line (HepG2) exerts toxic effects through mechanisms related to oxidative stress, and how cells deal with such exposure. Cell viability was determined by the MTT and protein content (PC) assays over 24, 48 and 72 h. The IC
REDUCTION OF NILUTAMIDE BY NO SYNTHASES : IMPLICATIONS FOR THE ADVERSE EFFECTS OF THIS NITROAROMATIC ANTIANDROGEN DRUG
2003
Nitric oxide synthases (NOSs) are flavohemeproteins that catalyze the oxidation of l-arginine to l-citrulline with formation of the widespread signal molecule NO. Beside their fundamental role in NO biosynthesis, these enzymes are also involved in the formation of reactive oxygen species and in the interactions with some xenobiotic compounds. Nilutamide is a nonsteroidal antiandrogen that behaves as a competitive antagonist of the androgen receptors and is proposed in the treatment of metastatic prostatic carcinoma. However, therapeutic effects of nilutamide are overshadowed by the occurrence of several adverse reactions mediated by toxic mechanism(s), which remain(s) poorly investigated. H…
Induction of apoptosis in human osteosarcoma Saos-2 cells by the proteasome inhibitor MG132 and the protective effect of pRb
2003
Induction of apoptosis in human osteosarcoma Saos-2 cells by the proteasome inhibitor MG132 and the protective effect of pRb
Perturbation of spermine synthase Gene Expression and Transcript Profiling Provide New Insights on the Role of the Tetraamine Spermine in Arabidopsis…
2011
The role of the tetraamine spermine in plant defense against pathogens was investigated by using the Arabidopsis (Arabidopsis thaliana)-Pseudomonas viridiflava pathosystem. The effects of perturbations of plant spermine levels on susceptibility to bacterial infection were evaluated in transgenic plants (35S::spermine synthase [SPMS]) that overexpressed the SPMS gene and accumulated spermine, as well as in spms mutants with low spermine levels. The former exhibited higher resistance to P. viridiflava than wild-type plants, while the latter were more susceptible. Exogenous supply of spermine to wild-type plants also increased disease resistance. Increased resistance provided by spermine was p…
Proteasome comprising a beta1 inducible subunit acts as a negative regulator of NADPH oxidase during elicitation of plant defense reactions.
2005
Elicitation of defense reactions in tobacco by cryptogein, triggered a production of active oxygen species (AOS) via the NADPH oxidase, NtrbohD, and an accumulation of beta1din, a defense induced beta-type subunit of 20S proteasome. The proteasome inhibitor, MG132, stimulated this AOS production. Tobacco cells transformed with sense constructs of beta1din showed an inhibition of the AOS production following elicitin treatment, whereas the antisense transformed cells showed a strongly enhanced AOS production. In cells transformed with sense construct of beta1din, the NtrbohD transcripts failed to be induced by cryptogein as observed in control and antisense transformed cells. Conversely, in …
The Measurement of Reactive Energy in Polluted Distribution Power Systems: An Analysis of the Performance of Commercial Static Meters
2008
This paper presents a comparative analysis of the performances of both a traditional induction meter and various types of commercial static meters for reactive energy in the presence of harmonic distortion. This is a topical issue, since there are several types of static meters on the market, based on different principles of construction. In accordance with current standards, these meters are designed to operate in sinusoidal conditions and their performance is not tested in the presence of harmonic distortion. However, with the increase of pollution levels in power systems, the meters may be used even in the presence of distorted voltages and/or currents; in such cases, their accuracy may …
A novel approach based on nonactive powers for the identification of disturbing loads in power systems
2007
In this paper, a new approach is proposed for the detection of harmonic sources in polluted power systems. It is a single- point strategy, based on a comparison among different "nonactive" power quantities proposed in literature that, in the same working conditions, assume different values at the same metering section. Some simulations tests were carried out on a standard IEEE test system proposed by other authors as a benchmark system for the analysis of multipoint measurement techniques for harmonic pollution monitoring. The obtained results show that the proposed single-point approach is in agreement with other strategies already proposed in the literature and can provide useful indicati…