Protein-mediated hydroxyl radical generation--the primary event in NADH oxidation and oxygen reduction by the granule rich fraction of human resting leukocytes.

The granule rich-fraction isolated from human resting polymorphonuclear leukocytes is capable of CN-insensitive NADH oxidation and O₂-uptake, accompanied by production of superoxide anion, hydroxyl radicals and H₂O₂. We showed that H₂O₂ initiates and maintains NADH oxidation and O₂-uptake but is also necessary for the formation of superoxide anion and hydroxyl radicals. It acts as a primary substrate for CN-insensitive protein-mediated formation of hydroxyl radicals, which in turn produce superoxide anions, probably through univalent oxidation of NADH as an intermediary.     

Studies on hemolysis of human erythrocytes by linoleic acid

The results presented in this paper show that lysis of human erythrocytes by linoleic acid is not caused by peroxidation of the fatty acid. Peroxidase, superoxide dismutase and scavengers of O ₂ ⁻ and OH had no effect on the lysis while catalase showed only marginal inhibition suggesting that O ₂ ⁻ , OH, O ₂ ⁻ and H₂O₂ do not play any direct role in hemolysis by linoleic acid. Generators of H₂O₂ inhibited the lysis completely and methemoglobin cells were more resistant to hemolysis by linoleic acid. The fatty acid did neither bind to nor fomed complex with red cell ghosts. Membrane oxidation of sulphydryl groups was also not involved in the lysis. Β-Carotene, retinol and bile salts enhanced the lysis, while, cholesterol but not cholesterol acetate, inhibited it. Taurocholate-pretreated cells were more susceptible to linoleic acid lysis. These observations suggested-that lysis by linoleic acid may be due to its detergent property.     

Some Dinophycean Red Tide Plankton Species Generate a Superoxide Scavenging Substance

Recent studies indicate that some raphidophycean red tide flagellates produce substances able to scavenge superoxide, whereas there have been no reports on superoxide scavenger production by dinophycean red tide flagellates. In this study, we examined the superoxide-scavenging activity of aqueous extracts from dinophycean red tide flagellates, Gymnodinium spp., Scrippsiella trochoidea, and Karenia sp., by a luminol analog L-012-dependent chemiluminescence (CL) method and an electron spin resonance (ESR)-spin trapping method, and compared the activity to that of raphidophycean red tide flagellates, Chattonella spp., Heterosigma akashiwo, and Fibrocapsa japonica. In the experiment applying the L-012-dependent CL method, only the aqueous extracts from raphidophycean red tide flagellates showed superoxide-scavenging activity. On the other hand, applying the ESR-spin trapping method, we found that the aqueous extracts from dinophycean red tide flagellates also showed superoxide-scavenging activity. This is the first report on the production of a superoxide-scavenger by dinophycean red tide flagellates.     

Bioreductive Activation of Quinones: Redox Properties and Thiol Reactivity

Redox properties and thiol reactivity are central to the therapeutic and toxicological properties of qui-nones. The use of other physicochemical parameters to establish predictive relationships for redox properties of quinones is discussed. and attention drawn to situations where such relationships may be unreliable. The rates of reaction of semiquinone radicals with oxygen, including those of chemotherapeutic agents such as mitomycin and the anthracyclines. can be predicted with reasonable confidence from the redox properties. The reactions of quinones with thiols such as glutathione produces reduced quinones and radicals. but the reactions are complex and all the features are not well understood     

An Antiaging Electrolyte Additive for High‐Energy‐Density Lithium‐Ion Batteries

High‐capacity Li‐rich layered oxide cathodes along with Si‐incorporated graphite anodes have high reversible capacity, outperforming the electrode materials used in existing commercial products. Hence, they are potential candidates for the development of high‐energy‐density lithium‐ion batteries (LIBs). However, structural degradation induced by loss of interfacial stability is a roadblock to their practical use. Here, the use of malonic acid‐decorated fullerene (MA‐C₆₀) with superoxide dismutase activity and water scavenging capability as an electrolyte additive to overcome the structural instability of high‐capacity electrodes that hampers the battery quality is reported. Deactivation of PF₅ by water scavenging leads to the long‐term stability of the interfacial structures of electrodes. Moreover, an MA‐C₆₀‐added electrolyte deactivates the reactive oxygen species and constructs an electrochemically robust cathode‐electrolyte interface for Li‐rich cathodes. This work paves the way for new possibilities in the design of electrolyte additives by eliminating undesirable reactive substances and tuning the interfacial structures of high‐capacity electrodes in LIBs.     

Oxidants and antioxidants in myocardial infarction (MI): Investigation of ischemia modified albumin,malondialdehyde, superoxide dismutase and catalase in individuals diagnosed with ST elevated myocardial infarction (STEMI) and non-STEMI (NSTEMI)

BackgroundCoronary ischemia can lead to myocardial damage and necrosis. The pathogenesis of cardiovascular diseases often includes increased oxidative stress and decreased antioxidant defense. The study aimed to assess levels of ischemia modified albumin (IMA), malondialdehyde acid (MDA), superoxide dismutase (SOD), and catalase in individuals diagnosed with ST elevated myocardial infarction (STEMI) and non-STEMI.MethodsThe present study prospectively included 50 STEMI patients, 55 NSTEMI patients, and 55 healthy subjects. Only patients who were recently diagnosed with STEMI or NSTEMI were included in this study. IMA, MDA, SOD, and catalase activities were measured spectrophotometrically. Significant coronary artery lesions were determined by angiography.ResultsPatients with ACS had significantly greater IMA and MDA values than the healthy controls (p<0.001). Besides, patients with STEMI had IMA levels that were significantly greater than those of the patients with NSTEMI (p<0.001), while the reverse was true for MDA levels (p<0.001). The healthy controls had the highest levels of SOD and catalase levels, followed by patients with STEMI and patients with NSTEMI, respectively (p<0.001). There was a significant negative correlation among MDA and SOD with catalase levels (r = -0.771 p<0.001 MDA vs catalase; r = -0.821 p<0.001 SOD vs catalase).ConclusionsData obtained in this study reveals that compared to healthy controls, STEMI and NSTEMI patients had increased levels of MDA and IMA and decreased levels of SOD and catalase.     

Comparison of superoxide detection abilities of newly developed spin traps in the living cells

This study compared the superoxide detection abilities of four spin traps, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DEPMPO), 5-(diphenylphosphinoyl)-5-methyl-1pyrroline N-oxide (DPPMPO) and 5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO) in living cells. Electron spin resonance (ESR) signals of the superoxide adducts were observed when spin traps were added to a suspension of human oral polymorphonuclear leukocytes (OPMNs) stimulated by phorbol 12-myristate 13-acetate. The ESR signal of the CYPMPO-superoxide adduct (CYPMPO-OOH) increased for 24 min after the initiation of the reaction, whereas the signals from DMPO-OOH and DPPMPO-OOH peaked at 6 and 10 min, respectively. The maximum concentrations of DMPO-OOH, DPPMPO-OOH and CYPMPO-OOH in OPMNs were 1.9, 6.0 and 10.7 µM, respectively. Furthermore, CYPMPO could more efficiently trap superoxide in blood PMNs compared with DEPMPO. From these results, it was concluded that CYPMPO performs better than DMPO, DPPMPO and DEPMPO for superoxide measurements in living cell systems because it has lower cytotoxicity and its superoxide adduct has a longer lifetime.     

SOD3 R231G polymorphism associated with coronary artery disease and myocardial infarction. The Ludwigshafen Risk and Cardiovascular Health (LURIC) study

This study examined the superoxide dismutase 3 (SOD3) R231G polymorphism in relation to the severity of coronary artery disease (CAD) and the risk of myocardial infarction (MI) in 3211 individuals; 94.4% of study participants were homozygous for SOD3 231RR and 5.5% were heterozygous for SOD3 231RG. The odds ratios of the RG and GG genotype (adjusted for age, gender and for conventional cardiovascular risk factors) were 2.02 (95% CI, 1.23–3.33, p=0.005) for the highest vs the lowest Friesinger coronary score and 1.40 (95% CI, 1.02–1.92, p=0.037) for MI, respectively. Further the SOD3 RG and GG genotype was associated with lower alpha-tocopherol levels than the wild type SOD3 RR genotype. It is concluded that the SOD3 231RG and GG genotype is associated with lower alpha-tocopherol levels and the severity of CAD and the risk of MI.     

The Effect of Xanthine/Xanthine Oxidase Generated Reactive Oxygen Species on Synaptic Transmission

The effect of reactive oxygen species generated by the interaction of xanthine and xanthine oxidase on synaptic transmission was examined at the squid giant synapse and the lobster neuromuscular junction. Exposure of these synaptic regions to xanthine/xanthine oxidase produced a significant depression in evoked release, with no change in either resting membrane properties or in the action potential. Addition of catalase to the xanthine/xanthine oxidase-containing media partially blocked the synaptic depression, indicating that H₂ O ₂ contributes to the synaptic changes induced by exposure to xanthine/xanthine oxidase. H₂ O ₂ applied directly to the perfusing media also produced a decrease in synaptic efficacy. The results demonstrate that reactive oxygen species, in general, depress evoked synaptic transmission.     

Cell Kinetic Evidence Suggests Elevated Oxidative Stress in Cultured Cells of Bloom's Syndrome

Bromodeoxyuridine/Hoechst flow cytometry was used to analyse disturbed cell proliferation of fibroblasts and lymphoblastoid cells from Bloom's syndrome (BS). Fibroblasts show poor activation, arrest in the G2 phase of the cell cycle along with a prolongation of the Gl phase. This pattern of perturbed cells proliferation is akin to that elicited in normal fibroblasts by 4-hydroxy-nonenal, a breakdown product of lipid peroxides. Treatment with vitamin E improved growth of BS fibroblasts more strongly than growth of normal fibroblasts. Lymphoblastoid cells from BS, to the contrary, experience only a minor arrest in the G2 phase after one round of bromodeoxyuridine incorporation, but are strongly inhibited during and after the second S phase. Thus, their cell cycle arrest is dependent upon BrdU incorporation, as has been found previously in normal cells exposed to elevated concentrations of oxygen or paraquat, a superoxide generating compound. These results suggest that BS cells may suffer from an elevated, endogenous generation of oxygen free radicals.