Search results for "Peroxidation"

2015

Oxidative stress is thought to be one of the main mediators of neuronal damage in human neurodegenerative disease. Still, the dissection of causal relationships has turned out to be remarkably difficult. Here, we have analyzed global protein oxidation in terms of carbonylation of membrane proteins and cytoplasmic proteins in three different mammalian species: aged human cortex and cerebellum from patients with or without Alzheimer's disease, mouse cortex and cerebellum from young and old animals, and adult rat hippocampus and cortex subjected or not subjected to cerebral ischemia. Most tissues showed relatively similar levels of protein oxidation. However, human cortex was affected by sever…

Enhanced susceptibility of cholesteryl sulfate-enriched low density lipoproteins to copper-mediated oxidation

1995

AbstractCholesteryl sulfate (CS) is a minor component of cell membranes, also present in lipoproteins, and its exact function is unknown. Since oxidation of low density lipoproteins (LDL) is thought to be an important determinant of atherogenesis, we investigated the influence of CS enrichment on copper-mediated oxidation of LDL. CS was found to act as a pro-oxidant, as measured by lipid oxidation parameters. The results also suggest that these effects were dependent on the sulfate group since pure cholesterol or cholesteryl acetate did not promote Cu2+-mediated oxidation. Our findings imply that CS may affect the oxidizability and hence the potential atherogenicity of LDL.

Differences in ozone sensitivity in three varieties of cabbage (Brassica oleracea L.) in the rural Mediterranean area

2002

Summary The effects of air quality with three levels of ozone (O 3 ) were studied on three cabbage varieties during a one month exposure period in the Valencia area by means of modulated chlorophyll (Chl) a fluorescence, lipid peroxidation and solute leakage. Increasing O 3 exposure reduced the maximum quantum yield of PSII photochemistry (F v /F m ) in line with a reduction in non-cyclic electron flow (ϕ PSII ), lower capacity to reduce the quinone pool (q P ) and a decrease in the potential phothosynthetic quantum conversion, Rfd ratio. These reductions were more evident in Caramba and Sentinel varieties but lower in Othelo. Ozone and its oxidative derivates weakened the plasmalemma, whic…

7-Nitroindazole protects striatal neurons against MPP+ -induced degeneration.

2006

The neuropathological hallmark of Parkinson's disease (PD) is the selective degeneration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). In this study, using a microdialysis technique, we investigated whether an inhibitor of neuronal nitric oxide synthase (nNOS), 7-nitrindazole (7-NI), could protect against DAergic neuronal damage induced by in vivo infusion of 1-methyl-4-phenylpiridinium iodide (MPP+) in freely moving rats. Experiments were performed over 2 days in three groups of rats: (a) nonlesioned, (b) MPP+-lesioned, and (c) 7-NI pretreated MPP+-lesioned rats. On day 1, control rats were perfused with an artificial CSF, while 1 mM MPP+ was infused into t…

Effects of pharmacological agents on the lifespan phenotype of Drosophila DJ-1beta mutants.

2010

Mutations in the DJ-1 gene cause autosomal recessive, early-onset Parkinsonism. The DJ-1 protein exerts a protective role against oxidative stress damage, working as a cellular oxidative stress sensor, and it seems to regulate gene expression at different levels. In Drosophila, two DJ-1 orthologs have been identified: DJ-1β and DJ-1β. Several studies have shown that loss of DJ-1β function causes Parkinson's disease (PD)-like phenotypes in flies such as age-dependent locomotor defects, reduced lifespan, and enhanced sensitivity to toxins that induce oxidative stress, like the herbicide paraquat. However, no dopaminergic neurodegeneration is observed. These results suggested that both locomot…

Inhibitory Effects of Various Extracts of Argentine Plant Species on Free-radical-mediated Reactions and Human Neutrophil Functions

1996

Extracts of Argentine plant species used in folk medicine were evaluated for their antioxidant properties and ability to influence human neutrophil functions, including superoxide anion release and degranulation. The infusion and methanol extract of Achyrocline flaccida, and the infusion of Pterocaulon polystachium exhibited chain-breaking antioxidant activity in Fe 2+ /ascorbate-induced lipid peroxidation of rat liver microsomal fractions and scavenged peroxyl radicals in an aqueous assay system. Nevertheless their superoxide scavenging ability was lower. The dichloromethane extracts of Phyllanthus sellowianus, Achyrocline flaccida, Gamochaeta simplicicaulis, Pterocaulon polystachium and E…

Hypoxia-induced dysfunction of rat diaphragm

2004

Contains fulltext : 47331.pdf (Publisher’s version ) (Closed access) Oxidants may play a role in hypoxia-induced respiratory muscle dysfunction. In the present study we hypothesized that hypoxia-induced impairment in diaphragm contractility is associated with elevated peroxynitrite generation. In addition, we hypothesized that strenuous contractility of the diaphragm increases peroxynitrite formation. In vitro force-frequency relationship, isotonic fatigability, and nitrotyrosine levels were assessed under hypoxic (Po(2) approximately 6.5 kPa) and hyperoxic (Po(2) approximately 88.2 kPa) control conditions and also in the presence of authentic peroxynitrite (60 min), ebselen (60 min), and t…

Oral N-acetylcysteine attenuates the rat pulmonary inflammatory response to antigen.

2003

Oxidative stress is involved in the pathophysiology of inflammatory airway diseases including asthma; therefore, antioxidants might be of clinical benefit in asthma treatment. In the present study, the effects of N-acetylcysteine on sensitised brown Norway rats were examined. N-Acetylcysteine (3 mmol kg body weight(-1) administered orally) was given daily for 1 week before challenge and various antigen-induced pulmonary responses were studied. Antigen exposure increased lipid peroxidation in bronchoalveolar lavage fluid (BALF) and oxidised glutathione levels in lung tissue 2 h after challenge. Lung nuclear transcription factor-KB-binding activity was increased 2 h after challenge, and BALF …

Oxidative and nitrosative stress in the diaphragm of patients with COPD.

2007

COPD is associated with an increased load on the diaphragm. Since chronic muscle loading results in changes in antioxidant capacity and formation of reactive oxygen and reactive nitrogen species, we hypothesized that COPD has a similar effect on the diaphragm, which is related to the severity of COPD. Catalase activity was determined spectrophotometrically. Levels of 4-hydroxy-2-nonenal (HNE)-protein adducts and 3-nitrotyrosine (NT) formation were measured using western blotting. Levels of malondialdehyde (MDA) were assessed by high-performance liquid chromatography. We found that catalase activity was approximately 89% higher in the diaphragm of severe COPD patients (FEV1 37+/-5% predicted…

Pyrrolo[3,2-h]quinazolines as Photochemotherapeutic Agents

2011

Heteroanalogues of angelicin, pyrrolo[3,2-h]quinazolines, were synthesized with the aim of obtaining new potent photochemotherapeutic agents. Many derivatives caused a significant decrease in cell proliferation in several human tumor cell lines after irradiation with UVA light (GI(50) =15.2-0.2 μM). Their phototoxicity effected apoptosis in Jurkat cells with the involvement of mitochondria (as determined by the loss of mitochondrial membrane potential and production of reactive oxygen species) and lysosomes. The phototoxicity of these compounds could be explained by lipid peroxidation.