Search results for "Superoxide"
showing 10 items of 462 documents
Low-temperature optical spectroscopy of cobalt in Cu,Co superoxide dismutase: a structural dynamics study of the solvent-unaccessible metal site.
1995
The temperature dependence (300 to 10 K) of the electronic absorption spectra of the cobalt chromophore in bovine superoxide dismutase (SOD) having the native Zn(II) ion selectivity replaced by Co(II) has been investigated in four different derivatives: Cu(II),Co(II) SOD, N3(-)-Cu(II), Co(II) SOD, Cu(I),Co(II) SOD, and E,Co(II) SOD in which the copper ion has been selectively removed. In the Cu(II),Co(II) SOD, the cobalt spectrum is characterized at room temperature by three bands centered at 18,472, 17,670, and 16,793 cm-1; the low-frequency band is split, at low temperatures, into two components, indicating a lower symmetry contribution to a predominantly tetrahedral crystal field. Additi…
β-Adrenoceptor stimulation up-regulates phosphodiesterase 4 activity and reduces prostaglandin E 2 -inhibitory effects in human neutrophils
2000
Human neutrophils were treated for 4 h with a combination of salbutamol (1 µM), a β2-adrenoceptor agonist, and rolipram (30 µM), a selective phosphodiesterase 4 inhibitor, to investigate whether this treatment produces up-regulation of phosphodiesterase activity with functional consequences. Anion-exchange chromatography coupled with the use of selective activators and inhibitors demonstrated that a phosphodiesterase activity with characteristics of the isoenzyme type 4 was increased in drug-treated cells. Kinetic analysis showed a ~1.5-fold increase in V max without alteration of K m values. The augmented phosphodiesterase activity in drug-treated cells was abolished by actinomycin D. Cycl…
Impairment of the extrusion transporter for asymmetric dimethyl-L-arginine: a novel mechanism underlying vasospastic angina.
2012
Abstract A 37-year old male patient presented with frequent angina attacks (up to 40/day) largely resistant to classical vasodilator therapy. The patient showed severe coronary and peripheral endothelial dysfunction, increased platelet aggregation and increased platelet-derived superoxide production. The endothelial nitric oxide synthase (eNOS)-inhibitor N G -nitro- l -arginine methyl ester (L-NAME) reduced superoxide formation in platelets identifying “uncoupled” eNOS as a superoxide source. Oral l -arginine normalized coronary and peripheral endothelial dysfunction and reduced platelet aggregation and eNOS-derived superoxide production. Plasma concentrations of the endogenous NOS inhibito…
Hematologic effects of recombinant human granulocyte colony-stimulating factor in patients with malignancy.
1989
Abstract The effect of recombinant human granulocyte colony-stimulating factor (G-CSF) on hematologic parameters was evaluated in a phase I clinical study in 18 patients with advanced malignancy. G-CSF was administered once daily as a 30-minute infusion for 14 days; three patients each were treated at increasing dose levels of 1, 3, 10, 30, and 60 micrograms kg-1 day-1. A transient decrease in neutrophil and monocyte counts was observed immediately after the G-CSF infusion, followed by a dose-dependent increase of up to 15-fold. G-CSF-induced neutrophils exhibited an increased O2- radical production, and serum levels of enzymes related to granulocyte turnover, including lysozyme and elastas…
Impairment of antioxidant enzymes, lipid peroxidation and 8-oxo-2'-deoxyguanosine in advanced epithelial ovarian carcinoma of a Spanish community.
2006
In the present study, we describe the changes of antioxidant enzyme activities and other oxidative stress-related parameters in a mediterranean cohort of women affected with epithelial ovarian carcinoma (EOC). For that purpose, the most representative enzymatic activities, such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the oxidized/reduced glutathione (GSSG/GSH) ratio have been analyzed in tumor tissue biopsies and compared with the normal tissue of the same patient. As oxidation products, the levels of malondialdehyde (MDA) as an indication of lipid peroxidation, and the DNA damaged base 8-oxo-2'-deoxyguanosine (8-oxo-dG) have been also measured. Ad…
Induction of heme oxygenase-1 and adaptive protection against the induction of DNA damage after hyperbaric oxygen treatment.
2000
Hyperbaric oxygen (HBO) treatment of human subjects (i.e. exposure to 100% oxygen at a pressure of 2.5 ATA for a total period of 3 x 20 min) caused clear and reproducible DNA damage in lymphocytes, as detected with the comet assay (single cell gel electrophoresis). Induction of DNA damage was found only after the first HBO exposure and not after further treatments of the same individuals. Furthermore, blood taken 24 h after HBO treatment was significantly protected against the induction of DNA damage by hydrogen peroxide (H(2)O(2)) in vitro, indicating that adaptation occurred due to induction of antioxidant defenses. The cells were not significantly protected against the genotoxic effects …
Hawthorn extract inhibits human isolated neutrophil functions.
2008
Hawthorn extract is a popular herbal medicine given as adjunctive treatment for chronic heart failure. In contrast to the cardiac properties of hawthorn extract, its anti-inflammatory effect has been scarcely investigated. This study examines the effects of a dry extract of leaves and flowers of Crataegus laevigata on various functional outputs of human neutrophils in vitro. Incubation of human neutrophils obtained from peripheral blood of healthy donors with C. laevigata extract (0.75-250 microg/ml) inhibited N-formyl-Met-Leu-Phe (FMLP)-induced superoxide anion generation, elastase release and chemotactic migration with potency values of 43.6, 21.9, and 31.6 microg/ml, respectively. By con…
Active paraplegics are protected against exercise-induced oxidative damage through the induction of antioxidant enzymes
2016
Exercise improves functional capacity in spinal cord injury (SCI). However, exhaustive exercise, especially when sporadic, is linked to the production of reactive oxygen species that may have a detrimental effect on SCI. We aimed to study the effect of a single bout of exhaustive exercise on systemic oxidative stress parameters and on the expression of antioxidant enzymes in individuals with paraplegia. The study was conducted in the Physical Therapy department and the Physical Education and Sports department of the University of Valencia. Sixteen paraplegic subjects were submitted to a graded exercise test (GET) until volitional exhaustion. They were divided into active or non-active group…
Role of Circulating miRNAs as Biomarkers in Idiopathic Pulmonary Arterial Hypertension: Possible Relevance of miR-23a
2015
Idiopathic pulmonary hypertension (IPAH) is a rare disease characterized by a progressive increase in pulmonary vascular resistance leading to heart failure. MicroRNAs (miRNAs) are small noncoding RNAs that control the expression of genes, including some involved in the progression of IPAH, as studied in animals and lung tissue. These molecules circulate freely in the blood and their expression is associated with the progression of different vascular pathologies. Here, we studied the expression profile of circulating miRNAs in 12 well-characterized IPAH patients using microarrays. We found significant changes in 61 miRNAs, of which the expression of miR23a was correlated with the patients’ …
Impaired plasma nitric oxide availability and extracellular superoxide dismutase activity in healthy humans with advancing age
2006
This study is aimed to verify the modifications of extracellular superoxide dismutase (EC-SOD) activity and its potential involvement on the mechanism responsible for the impairment of plasma nitric oxide (NO) availability occurring with advancing age in healthy humans. For this purpose, plasma samples were drawn from 40 healthy men, aged 20-92 years, in fasting state and used for measurements of stable end-product nitrite/nitrate (NOx), as expression of NO availability, EC-SOD activity, thiobarbituric acid reactive substances (TBARS) as marker of lipid peroxidation, Trolox equivalent antioxidant capacity (TEAC) as a measure of plasma total antioxidant capacity, and in vitro susceptibility …