Search results for "Active oxygen"
showing 10 items of 884 documents
Sodium metabisulfite as a cytotoxic food additive induces apoptosis in HFFF2 cells
2021
Sodium metabisulfite (SMB), an antioxidant agent, is extensively used as a preservative in food industry. The current study was aimed to clarify its potential toxic effects on human fetal foreskin fibroblasts (HFFF2) cells, in vitro. Subsequently, MTT results illustrated that exposure to SMB significantly (p 0.0001) decreased HFFF2 cell viability in a dose-dependent manner, and the concentration of 25 μM reduced cell survival rates to 50% as the half-maximal inhibitory concentration of SMB. It was further shown that SMB exerted this cytotoxic effect on HFFF2 cells through apoptosis induction. qRT-PCR and western blotting results showed that treatment of HFFF2 cells with this food additive …
Glutamine potentiates TNF-α-induced tumor cytotoxicity
2001
L-glutamine (Gln) sensitizes tumor cells to tumor necrosis factor (TNF)-alpha-induced cytotoxicity. The type and mechanism of cell death induced by TNF-alpha was studied in Ehrlich ascites tumor (EAT)-bearing mice fed a Gln-enriched diet (GED; where 30% of the total dietary nitrogen was from Gln). A high rate of Gln oxidation promotes a selective depletion of mitochondrial glutathione (mtGSH) content to approximately 58% of the level found in tumor mitochondria of mice fed a nutritionally complete elemental diet (standard diet, SD). The mechanism of mtGSH depletion involves a glutamate-induced inhibition of GSH transport from the cytosol into mitochondria. The increase in reactive oxygen in…
Catchup: a mouse model for imaging-based tracking and modulation of neutrophil granulocytes
2015
Neutrophil granulocyte biology is a central issue of immunological research, but the lack of animal models that allow for neutrophil-selective genetic manipulation has delayed progress. By modulating the neutrophil-specific locus Ly6G with a knock-in allele expressing Cre recombinase and the fluorescent protein tdTomato, we generated a mouse model termed Catchup that exhibits strong neutrophil specificity. Transgene activity was found only in very few eosinophils and basophils and was undetectable in bone marrow precursors, including granulomonocytic progenitors (GMPs). Cre-mediated reporter-gene activation allowed for intravital two-photon microscopy of neutrophils without adoptive transfe…
Cigarette smoke exposure up-regulates endothelin receptor B in human pulmonary artery endothelial cells: molecular and functional consequences
2010
BACKGROUND AND PURPOSEPulmonary arteries from smokers and chronic obstructive pulmonary disease patients show abnormal endothelium-dependent vascular reactivity. We studied the effect of cigarette smoke extract (CSE) on endothelin receptor B (ETB) expression in human pulmonary artery endothelial cells (HPAECs) and its role in endothelial dysfunction.EXPERIMENTAL APPROACHETB receptor expression was measured by real time RT-PCR, Western blot and immunofluorescence. Cell contraction, intracellular Ca2+, F/G-actin, RhoA activity, myosin light chain phosphorylation, ET, NO, thromboxane (Tx)A2 and reactive oxygen species (ROS) were measured by traction microscopy, fluorescence microscopy, phalloi…
In vitro study of human alveolar macrophage and peripheral blood mononuclear cell reactive oxygen-intermediates release induced by sulfur dioxide at …
1994
Sulfur dioxide (SO2) is a major air pollutant in urban areas. Alveolar macrophages (AM) located on the alveolar surface are in direct contact with this inhaled gas. We evaluated the dose-dependent effect of SO2 exposure on the oxidative metabolism of AM and peripheral blood mononuclear cells (PBMNC) by measuring the spontaneous and stimulated reactive oxygen intermediates (ROI) release. AM or PBMNC were placed on a polycarbonate membrane, which was in direct contact with the surface of a nutrient reservoir. For exposure of the cells to SO2 a special chamber was employed, in which humidified standard air with 5% CO2 at 37 degrees C was mixed with SO2 at the desired concentration. Periods of …
Glutathione Peroxidase 1 Activity and Cardiovascular Events in Patients With Coronary Artery Disease
2003
Along with superoxide dismutase, glutathione peroxidase 1 is one of the cellular antioxidant enzymes that have a key role in controlling reactive oxygen species. It uses glutathione to reduce hydrogen peroxide to water and lipid peroxides to their respective alcohols. There are suggestions from in vitro and animal studies that these enzymes could protect against atherosclerosis. This prospective study examined the possibility that relatively high activity of antioxidant enzymes protects against cardiovascular events. The study population included 636 patients suspected of having coronary artery disease who were followed for a median period of 4.7 years. Stable angina was present in 510 pati…
Mucositis and salivary antioxidants in patients undergoing bone marrow transplantation (BMT)
2014
Objectives: High doses of chemotherapy generate DNA damage in patients undergoing bone marrow transplantation (BMT), due to the production of reactive oxygen species (ROS). In order to evaluate the local defensive effectiveness of the patient undergoing BMT, the concentrations of the antioxidants superoxide dismutase (SOD) and uric acid (UA) were measured in saliva. Study Design: Basal saliva samples were collected from 20 patients undergoing BMT at the Oncology Depart- ment, Sanatorio Allende (Córdoba), in the stages: initial, prior to conditioning therapy (I); middle: 7 to 10 days after BMT (M) and final stage, 30 days after discharge from isolation (F). SOD levels were determined using a…
Mutagenicity spectra in Salmonella typhimurium strains of glutathione, L-cysteine and active oxygen species
1989
Glutathione and L-cysteine, in the presence of rat kidney post-mitochondrial supernatant (S9) fraction, and various forms of active oxygen were investigated for mutagenicity in seven his- strains of Salmonella typhimurium. Glutathione and L-cysteine showed qualitatively and quantitatively virtually identical mutagenic activities. The number of mutants induced in strain TA97 was 3-4 times higher than in TA100, the strain in which the mutagenicity was originally detected. Mutagenic effects were also observed in strains TA92, TA102 and TA104, but not in TA1535 and TA1537. Hydrogen peroxide, superoxide and glucose/glucose oxidase in the presence and absence of kidney S9 fraction showed pronounc…
Pneumocyte Apoptosis Induction during Cardiopulmonary Bypass: Effective Prevention by Radical Scavenging UsingN-Acetylcysteine
2007
Cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with pulmonary dysfunction. We sought to investigate whether pulmonary ischemia/reperfusion during standard CPB and cardioplegic arrest is associated with reactive oxygen species (ROS)-mediated pulmonary tissue injury and pneumocyte apoptosis induction, and whether ROS scavenging using N-acetylcysteine (NAC) attenuates these alterations. Twelve pigs (41 +/- 8 kg) were randomized to receive either NAC (100 mg/kg prior to CPB; n = 7) or placebo (n = 5) and subjected to CPB and 60 min of cold (4 degrees C) crystalloid cardioplegic arrest. We collected lung biopsies prior to CPB, at 60 min CPB, as well as at 30, 60, and 120 min…
Replenishment of glutathione levels improves mucosal function in experimental acute colitis.
2000
Because reactive oxygen species (ROS) have been implicated as mediators of inflammatory bowel disease (IBD), the purpose of the present work was to determine the functional role of mucosal GSH in the trinitrobenzenesulfonic acid in 50% ethanol (TNBS+ethanol)-induced colitis in rats. Mucosal samples were taken to evaluate the temporal relationship between the extent of injury, the levels of glutathione (GSH) during acute colitis induced by TNBS+ethanol, and the effect of N-acetylcysteine (NAC) administration. In vitro assays revealed the interaction of TNBS with GSH leading to the almost instantaneous disappearance of GSH, while the reductive metabolism of TNBS by GSSG reductase generated RO…