Search results for "Superoxide"
showing 10 items of 462 documents
Mechanism of Reaction of Melatonin with Human Myeloperoxidase
2001
Recently, it was suggested that melatonin (N-acetyl-5-methoxytryptamine) is oxidized by activated neutrophils in a reaction most probably involving myeloperoxidase (Biochem. Biophys. Res. Commun. (2000) 279, 657-662). Myeloperoxidase (MPO) is the most abundant protein of neutrophils and is involved in killing invading pathogens. To clarify if melatonin is a substrate of MPO, we investigated the oxidation of melatonin by its redox intermediates compounds I and II using transient-state spectral and kinetic measurements at 25 degrees C. Spectral and kinetic analysis revealed that both compound I and compound II oxidize melatonin via one-electron processes. The second-order rate constant measur…
Heparin–polynitroxides: Synthesis and preliminary evaluation as cardiovascular EPR/MR imaging probes and extracellular space-targeted antioxidants
2011
We report here the synthesis of heparin-polynitroxide derivatives (HPNs) in which nitroxide moieties are linked either to uronic acid or glycosamine residues of the heparin macromolecule. HPNs have low anticoagulant activity, possess superoxide scavenging properties, bind to the vascular endothelium/extra-cellular matrix and can be detected by EPR and MRI techniques. As the vascular wall-targeted redox-active paramagnetic compounds, HPNs may have both diagnostic (molecular MRI) and therapeutic (ecSOD mimics) applications.
Traditional Chinese herbal medicine at the forefront battle against COVID-19: Clinical experience and scientific basis.
2020
Abstract Background Throughout the 5000-year history of China, more than 300 epidemics were recorded. Traditional Chinese herbal medicine (TCM) has been used effectively to combat each of these epidemics’ infections, and saved many lives. To date, there are hundreds of herbal TCM formulae developed for the purpose of prevention and treatment during epidemic infections. When COVID-19 ravaged the Wuhan district in China in early January 2020, without a deep understanding about the nature of COVID-19, patients admitted to the TCM Hospital in Wuhan were immediately treated with TCM and reported later with >90% efficacy. Approach We conducted conduct a systematic survey of various TCM herbal pre…
An in vitro procedure for evaluation of early stage oxidative stress in an established fish cell line applied to investigation of PHAH and pesticide …
2004
Oxidative stress by increased production of reactive oxygen species such as superoxide has been implicated in the toxicity of PCB's and non-target toxicity of many pesticides. We report the development of a microplate-based method for determination of early stage oxidative stress using an established cell line (EPC) from a skin tumour of carp Cyprinus carpio L. and 2',7'-dichlorodihydrofluorescein diacetate (H(2)-DCFDA) as a fluorescent probe for detection of reactive oxygen species (ROS) formation. Sublethal concentrations of the herbicide Paraquat, an established redox cycling agent and a crude PCB mixture, Arochlor 1254 elicited a linear increase in ROS formation over 2 h exposure which …
Tumour-cell-endothelial interactions: free radicals are mediators of melanoma-induced endothelial cell damage
1996
Damage to vascular endothelium may play an important role during metastasis. We used a three-dimensional model of tumour cell extravasation to test the hypothesis that certain types of tumour cells are able to induce vascular endothelial cell injury. Multicellular tumour spheroids (MCTS) of 14 human cancer cell lines and spheroids from two benign cell lines were transferred onto confluent monolayers of human endothelial cells (EC). MCTS from 4 of 7 melanoma cell lines induced damage of the endothelium which was closely associated with tumour cell attachment. Endothelial cell injury became evident morphologically by loss of cell membrane integrity and sensitivity to shear stress. Similar res…
Regulation of Anti-Apoptotic SOD2 and BIRC3 in Periodontal Cells and Tissues.
2021
Made available in DSpace on 2021-06-25T10:49:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-02 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Deutscher Akademischer Austauschdienst Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Deutsche Forschungsgemeinschaft The aim of the study was to clarify whether orthodontic forces and periodontitis interact with respect to the anti-apoptotic molecules superoxide dismutase 2 (SOD2) and baculoviral IAP repeat-containing protein 3 (BIRC3). SOD2, BIRC3, and the apoptotic markers caspases 3 (CASP3) and 9 (CASP9) were analyzed in gingiva from periodontally healthy and periodontitis subjects by real-time PCR…
Influence of Agents Used for Topical Wound Treatment on Phagocyte Stimulation and Fibroblast Growth
1995
Wound healing has always been a fascinating phenomenon for physicians and surgeons. Wounds usually close by forming new granulation tissue, contracting, and re-epithelializing. Before granulation begins, polymor-phonuclear leukocytes (PMNs) and monocytes/macrophages (MCs) are chemotactically attracted to sites of injury. Upon contact with various stimuli in the wound including bioactive lipids, complement components, certain cytokines, e.g., tumor necrosis factor-α (TNF-α) [1], granulocyte/ monocyte-colony stimulating factor (GM-CSF), interferon-γ (IFN-γ), and interleukin-8, and particles such as microorganisms, phagocytes respond by a respiratory burst consisting of a markedly enhanced upt…
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…
The effects of the nitric oxide donors molsidomine and SIN-1 on human polymorphonuclear leucocyte functionin vitro andex vivo
1992
The nitrovasodilator and nitric oxide donor molsidomine and its metabolite SIN-I dilate vascular smooth muscle and inhibit platelet activation by increasing intracellular concentrations of cyclic GMP We have therefore studied the effects of molsidomine and SIN-I on isolated human polymorphonuclear leucocytes (PMN)in vitro andex vivo. In vitro molsidomine dose-dependently reducedβ-glucuronidase release and the generation of superoxide anions from non-activated and from FMLP- or PAF-stimulated human PMNs. SIN-1 was equally effective in reducing (β-glucuronidase release and totally inhibited oxygen radical generation at a concentration of 580 μmol · l−1. In a double-blind, placebo-controlled, …
In vivo antioxidant treatment protects against bleomycin-induced lung damage in rats
2003
1. This study examines the activity of the antioxidant N-acetylcysteine on bleomycin-induced pulmonary fibrosis in rats with emphasis on the early inflammatory phase. 2. Rats receiving N-acetylcysteine (300 mg kg(-1) day(-1), intraperitoneal) had less augmented lung wet weight, and lower levels of proteins, lactate dehydrogenase, neutrophil and macrophage counts in bronchoalveolar lavage fluid and lung myeloperoxidase activity with a betterment of histological score at 3 days postbleomycin. 3. A diminished lung GSH/GSSG ratio and augmented lipid hydroperoxides were observed 3 days postbleomycin. These changes were attenuated by N-acetylcysteine. Alveolar macrophages from bleomycin-exposed r…