Search results for "Dative"

Formation of covalent di-tyrosine dimers in recombinant α-synuclein

2015

Parkinson's disease is associated with fibril deposition in the diseased brain. Misfolding events of the intrinsically disordered synaptic protein α-synuclein are suggested to lead to the formation of transient oligomeric and cytotoxic species. The etiology of Parkinson's disease is further associated with mitochondrial dysfunction and formation of reactive oxygen species. Oxidative stress causes chemical modification of native α-synuclein, plausibly further influencing misfolding events. Here, we present evidence for the spontaneous formation of covalent di-tyrosine α-synuclein dimers in standard recombinant protein preparations, induced without extrinsic oxidative or nitrative agents. The…

2013

Re-canalization of cerebral vessels in ischemic stroke is pivotal to rescue dysfunctional brain areas that are exposed to moderate hypoxia within the penumbra from irreversible cell death. Goal of the present study was to evaluate the effect of moderate hypoxia followed by reoxygenation (MHR) on the evolution of reactive oxygen species (ROS) and blood-brain barrier (BBB) integrity in brain endothelial cells (BEC). BBB integrity was assessed in BEC in vitro and in microvessels of the guinea pig whole brain in situ preparation. Probes were exposed to MHR (2 hours 67-70 mmHg O2, 3 hours reoxygenation, BEC) or towards occlusion of the arteria cerebri media (MCAO) with or without subsequent repe…

Mitochondrial oxidative stress and CD95 ligand: A dual mechanism for hepatocyte apoptosis in chronic alcoholism

2002

Apoptosis plays an important role in the progression of alcohol-induced liver disease to cirrhosis. Oxidative stress is an early event in the development of apoptosis. The major aim of this study was to study the conditions in which oxidative stress occurs in chronic alcoholism and its relationship with apoptosis of hepatocytes. We have found that oxidative stress is associated with chronic ethanol consumption in humans and in rats, in the former independently of the existence of alcohol-induced liver disease. Ethanol or acetaldehyde induces apoptosis in hepatocytes isolated from alcoholic rats, but not in those from control rats. Inhibition of aldehyde dehydrogenase, but not of cytochrome …

The Relationship between Alcohol–induced Apoptosis and Oxidative Stress in the Liver

2005

This chapter discusses the relationship of apoptosis and oxidative stress induced by alcohol in the liver. Oxidative stress is involved in the pathogenesis and progression of alcohol-induced liver disease. Chronic alcoholism always causes oxidative stress independently of the presence of liver disease. Two key mechanisms are responsible for it: (1) the mitochondrial respiratory chain and (2) cytochrome P450 2El activity. Increased production of reactive oxygen species at complexes I and III together with NADH overproduction would be the major cause for mitochondrial oxidative stress in chronic alcoholism. Reactive Oxygen Species (ROS) cause oxidative damage, which may lead to cell death by …

Oxidative stress in diabetic retinopathy

2020

Diabetic retinopathy (DR) is the leading cause of acquired blindness in working adults worldwide. Biochemical changes in DR contribute to both the microscopic structural and functional changes in the retina. All these alterations result in retinal damage that can be assessed by funduscopy, optical coherence tomography (OCT), and angioOCT. Reactive oxygen species (ROS) overproduction in the mitochondria is considered a causal link between elevated glucose and biochemical abnormalities in the pathophysiology of DR. Moreover, oxidative-induced pathways also seem to provide positive feedback to ROS production, resulting in a vicious cycle. ROS can directly damage lipids, proteins, and DNA, lead…

2021

Cardiovascular diseases (CVDs) rank the leading cause of morbidity and mortality globally. Obesity and its related metabolic syndrome are well-established risk factors for CVDs. Therefore, understanding the pathophysiological role of adipose tissues is of great importance in maintaining cardiovascular health. Oxidative stress, characterized by excessive formation of reactive oxygen species, is a common cellular stress shared by obesity and CVDs. While plenty of literatures have illustrated the vascular oxidative stress, very few have discussed the impact of oxidative stress in adipose tissues. Adipose tissues can communicate with vascular systems, in an endocrine and paracrine manner, throu…

Oxidative stress in osteoarticular diseases

2016

Epigenetics, oxidative states and diabetes

2020

Abstract Although controlling a wide range of physiological cell functions, redox states unbalance during inflammation toward oxidative stress. Specific regions of our genome are extremely sensitive to both oxygen and reactive oxygen species, therefore modulating gene transcription in response to this specific epigenetic effect. Additional epigenetic mechanisms may include the alteration of the methylation states of DNA, protein and lipid nitration or modulation of specific microRNAs. A crucial role in finely tuning redox states is also played by mitochondria, where oxidative phosphorylation is epigenetically controlled. Diabetes, the most considerable “epigenetic” clinical disorder, exacer…

Electrochemical sensor for evaluating oxidative stress in airway epithelial cells

2021

Cigarette smoke exposure induces oxidative stress within the airways. Increased oxidative burden contributes to the pathogenesis of chronic lung disorders and is associated with aging and chronic inflammation. Airway epithelial cells highly contribute to Reactive Oxygen Species (ROS) generation within injured and inflamed lung tissues. Among ROS, hydrogen peroxide (H2O2) can be monitored in the extracellular space. Herein, we present an amperometric/voltammetric sensor based on gold nanoparticles and graphene oxide able to detect H2O2 with good sensitivity and selectivity. Using this sensor, H2O2 release was measured in conditioned medium from primary bronchial epithelial cells (PBEC), bron…

Oxidative Stress and DNA Damage in Obesity-Related Tumorigenesis

2014

Reactive oxygen species induce oxidative modification of critical macromolecules. Oxygen derived free radicals may act as potential cytotoxic intermediates inducing inflammatory and degenerative processes, or as signal messengers for the regulation of gene expression. This dual effect mainly depends on the availability of free radicals in terms of concentration, as well as on the environmental characteristics in which they are produced. The formation of free radicals has been proposed to be the linking factor between certain metabolic disturbances and cancer. Circulating mononuclear cells of patients with high cholesterol levels, insulin resistance, metabolic syndrome or obesity present low…