Superoxides: Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.Superoxide Dismutase: An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC 126.96.36.199.Catalase: An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.NADPH Oxidase: A flavoprotein enzyme that catalyzes the univalent reduction of OXYGEN using NADPH as an electron donor to create SUPEROXIDE ANION. The enzyme is dependent on a variety of CYTOCHROMES. Defects in the production of superoxide ions by enzymes such as NADPH oxidase result in GRANULOMATOUS DISEASE, CHRONIC.Oxidative Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.Reactive Oxygen Species: Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.Free Radical Scavengers: Substances that influence the course of a chemical reaction by ready combination with free radicals. Among other effects, this combining activity protects pancreatic islets against damage by cytokines and prevents myocardial and pulmonary perfusion injuries.Antioxidants: Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.Xanthine Oxidase: An iron-molybdenum flavoprotein containing FLAVIN-ADENINE DINUCLEOTIDE that oxidizes hypoxanthine, some other purines and pterins, and aldehydes. Deficiency of the enzyme, an autosomal recessive trait, causes xanthinuria.Free Radicals: Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.Cyclic N-Oxides: Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.Paraquat: A poisonous dipyridilium compound used as contact herbicide. Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Nitric Oxide: A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.Neutrophils: Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.Glutathione Peroxidase: An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC 188.8.131.52.Ditiocarb: A chelating agent that has been used to mobilize toxic metals from the tissues of humans and experimental animals. It is the main metabolite of DISULFIRAM.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Nitroblue Tetrazolium: Colorless to yellow dye that is reducible to blue or black formazan crystals by certain cells; formerly used to distinguish between nonbacterial and bacterial diseases, the latter causing neutrophils to reduce the dye; used to confirm diagnosis of chronic granulomatous disease.Metalloporphyrins: Porphyrins which are combined with a metal ion. The metal is bound equally to all four nitrogen atoms of the pyrrole rings. They possess characteristic absorption spectra which can be utilized for identification or quantitative estimation of porphyrins and porphyrin-bound compounds.Peroxynitrous Acid: A potent oxidant synthesized by the cell during its normal metabolism. Peroxynitrite is formed from the reaction of two free radicals, NITRIC OXIDE and the superoxide anion (SUPEROXIDES).Spin Labels: Molecules which contain an atom or a group of atoms exhibiting an unpaired electron spin that can be detected by electron spin resonance spectroscopy and can be bonded to another molecule. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed)Copper: A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.Lipid Peroxidation: Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.Hydroxyl Radical: The univalent radical OH. Hydroxyl radical is a potent oxidizing agent.Manganese: A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)NADH, NADPH Oxidoreductases: A group of oxidoreductases that act on NADH or NADPH. In general, enzymes using NADH or NADPH to reduce a substrate are classified according to the reverse reaction, in which NAD+ or NADP+ is formally regarded as an acceptor. This subclass includes only those enzymes in which some other redox carrier is the acceptor. (Enzyme Nomenclature, 1992, p100) EC 1.6.Malondialdehyde: The dialdehyde of malonic acid.Oxidants: Electron-accepting molecules in chemical reactions in which electrons are transferred from one molecule to another (OXIDATION-REDUCTION).Mitochondria: Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)N-Formylmethionine Leucyl-Phenylalanine: A formylated tripeptide originally isolated from bacterial filtrates that is positively chemotactic to polymorphonuclear leucocytes, and causes them to release lysosomal enzymes and become metabolically activated.AcetophenonesElectron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt: A colorimetric reagent for iron, manganese, titanium, molybdenum, and complexes of zirconium. (From Merck Index, 11th ed)Hydroxides: Inorganic compounds that contain the OH- group.Glutathione: A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.Xanthine: A purine base found in most body tissues and fluids, certain plants, and some urinary calculi. It is an intermediate in the degradation of adenosine monophosphate to uric acid, being formed by oxidation of hypoxanthine. The methylated xanthine compounds caffeine, theobromine, and theophylline and their derivatives are used in medicine for their bronchodilator effects. (Dorland, 28th ed)Nitrates: Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.Pyrogallol: A trihydroxybenzene or dihydroxy phenol that can be prepared by heating GALLIC ACID.Respiratory Burst: A large increase in oxygen uptake by neutrophils and most types of tissue macrophages through activation of an NADPH-cytochrome b-dependent oxidase that reduces oxygen to a superoxide. Individuals with an inherited defect in which the oxidase that reduces oxygen to superoxide is decreased or absent (GRANULOMATOUS DISEASE, CHRONIC) often die as a result of recurrent bacterial infections.Luminescent Measurements: Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Spin Trapping: A technique for detecting short-lived reactive FREE RADICALS in biological systems by providing a nitrone or nitrose compound for an addition reaction to occur which produces an ELECTRON SPIN RESONANCE SPECTROSCOPY-detectable aminoxyl radical. In spin trapping, the compound trapping the radical is called the spin trap and the addition product of the radical is identified as the spin adduct. (Free Rad Res Comm 1990;9(3-6):163)Amyotrophic Lateral Sclerosis: A degenerative disorder affecting upper MOTOR NEURONS in the brain and lower motor neurons in the brain stem and SPINAL CORD. Disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. Clinical manifestations include progressive weakness, atrophy, FASCICULATION, hyperreflexia, DYSARTHRIA, dysphagia, and eventual paralysis of respiratory function. Pathologic features include the replacement of motor neurons with fibrous ASTROCYTES and atrophy of anterior SPINAL NERVE ROOTS and corticospinal tracts. (From Adams et al., Principles of Neurology, 6th ed, pp1089-94)Nitric Oxide Synthase: An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.Biopterin: A natural product that has been considered as a growth factor for some insects.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Nitric Oxide Synthase Type III: A CALCIUM-dependent, constitutively-expressed form of nitric oxide synthase found primarily in ENDOTHELIAL CELLS.Thiobarbituric Acid Reactive Substances: Low-molecular-weight end products, probably malondialdehyde, that are formed during the decomposition of lipid peroxidation products. These compounds react with thiobarbituric acid to form a fluorescent red adduct.Onium Compounds: Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Kinetics: The rate dynamics in chemical or physical systems.PhenanthridinesMolsidomine: A morpholinyl sydnone imine ethyl ester, having a nitrogen in place of the keto oxygen. It acts as NITRIC OXIDE DONORS and is a vasodilator that has been used in ANGINA PECTORIS.Hypoxanthine: A purine and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.Glutathione Reductase: Catalyzes the oxidation of GLUTATHIONE to GLUTATHIONE DISULFIDE in the presence of NADP+. Deficiency in the enzyme is associated with HEMOLYTIC ANEMIA. Formerly listed as EC 184.108.40.206.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Oxypurinol: A xanthine oxidase inhibitor.Peroxidase: A hemeprotein from leukocytes. Deficiency of this enzyme leads to a hereditary disorder coupled with disseminated moniliasis. It catalyzes the conversion of a donor and peroxide to an oxidized donor and water. EC 220.127.116.11.NADPH Dehydrogenase: A flavoprotein that reversibly oxidizes NADPH to NADP and a reduced acceptor. EC 18.104.22.168.ZymosanNADP: Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)Tetradecanoylphorbol Acetate: A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.Vitamin K 3: A synthetic naphthoquinone without the isoprenoid side chain and biological activity, but can be converted to active vitamin K2, menaquinone, after alkylation in vivo.Phagocytes: Cells that can carry out the process of PHAGOCYTOSIS.Ascorbic Acid: A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.Aconitate Hydratase: An enzyme that catalyzes the reversible hydration of cis-aconitate to yield citrate or isocitrate. It is one of the citric acid cycle enzymes. EC 22.214.171.124.Aorta: The main trunk of the systemic arteries.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Cytochrome c Group: A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)Lipid Peroxides: Peroxides produced in the presence of a free radical by the oxidation of unsaturated fatty acids in the cell in the presence of molecular oxygen. The formation of lipid peroxides results in the destruction of the original lipid leading to the loss of integrity of the membranes. They therefore cause a variety of toxic effects in vivo and their formation is considered a pathological process in biological systems. Their formation can be inhibited by antioxidants, such as vitamin E, structural separation or low oxygen tension.Granulomatous Disease, Chronic: A defect of leukocyte function in which phagocytic cells ingest but fail to digest bacteria, resulting in recurring bacterial infections with granuloma formation. When chronic granulomatous disease is caused by mutations in the CYBB gene, the condition is inherited in an X-linked recessive pattern. When chronic granulomatous disease is caused by CYBA, NCF1, NCF2, or NCF4 gene mutations, the condition is inherited in an autosomal recessive pattern.Nitrogen Oxides: Inorganic oxides that contain nitrogen.Pulse Radiolysis: Use of a pulse of X-rays or fast electrons to generate free radicals for spectroscopic examination.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Mice, Inbred C57BLDisease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.PeroxidasesNitric Oxide Donors: A diverse group of agents, with unique chemical structures and biochemical requirements, which generate NITRIC OXIDE. These compounds have been used in the treatment of cardiovascular diseases and the management of acute myocardial infarction, acute and chronic congestive heart failure, and surgical control of blood pressure. (Adv Pharmacol 1995;34:361-81)Aerobiosis: Life or metabolic reactions occurring in an environment containing oxygen.Time Factors: Elements of limited time intervals, contributing to particular results or situations.AcridinesEthidium: A trypanocidal agent and possible antiviral agent that is widely used in experimental cell biology and biochemistry. Ethidium has several experimentally useful properties including binding to nucleic acids, noncompetitive inhibition of nicotinic acetylcholine receptors, and fluorescence among others. It is most commonly used as the bromide.Peroxides: A group of compounds that contain a bivalent O-O group, i.e., the oxygen atoms are univalent. They can either be inorganic or organic in nature. Such compounds release atomic (nascent) oxygen readily. Thus they are strong oxidizing agents and fire hazards when in contact with combustible materials, especially under high-temperature conditions. The chief industrial uses of peroxides are as oxidizing agents, bleaching agents, and initiators of polymerization. (From Hawley's Condensed Chemical Dictionary, 11th ed)Plant Extracts: Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Cyanides: Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Phagocytosis: The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).Apoptosis: One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.Electron Transport Complex I: A flavoprotein and iron sulfur-containing oxidoreductase complex that catalyzes the conversion of UBIQUINONE to ubiquinol. In MITOCHONDRIA the complex also couples its reaction to the transport of PROTONS across the internal mitochondrial membrane. The NADH DEHYDROGENASE component of the complex can be isolated and is listed as EC 126.96.36.199.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Organometallic Compounds: A class of compounds of the type R-M, where a C atom is joined directly to any other element except H, C, N, O, F, Cl, Br, I, or At. (Grant & Hackh's Chemical Dictionary, 5th ed)RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Anions: Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.Extracellular Space: Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.Neutrophil Activation: The process in which the neutrophil is stimulated by diverse substances, resulting in degranulation and/or generation of reactive oxygen products, and culminating in the destruction of invading pathogens. The stimulatory substances, including opsonized particles, immune complexes, and chemotactic factors, bind to specific cell-surface receptors on the neutrophil.Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.Antimycin A: An antibiotic substance produced by Streptomyces species. It inhibits mitochondrial respiration and may deplete cellular levels of ATP. Antimycin A1 has been used as a fungicide, insecticide, and miticide. (From Merck Index, 12th ed)Macrophages: The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)MethemoglobinReactive Nitrogen Species: Nitrogenous products of NITRIC OXIDE synthases, ranging from NITRIC OXIDE to NITRATES. These reactive nitrogen intermediates also include the inorganic PEROXYNITROUS ACID and the organic S-NITROSOTHIOLS.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Rotenone: A botanical insecticide that is an inhibitor of mitochondrial electron transport.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Nitric Oxide Synthase Type II: A CALCIUM-independent subtype of nitric oxide synthase that may play a role in immune function. It is an inducible enzyme whose expression is transcriptionally regulated by a variety of CYTOKINES.Nitrites: Salts of nitrous acid or compounds containing the group NO2-. The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. The organic nitrites may be isomeric, but not identical with the corresponding nitro compounds. (Grant & Hackh's Chemical Dictionary, 5th ed)Sulfhydryl Compounds: Compounds containing the -SH radical.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Nitroprusside: A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Allopurinol: A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.Vitamin E: A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS.Cytochrome b Group: Cytochromes (electron-transporting proteins) with protoheme (HEME B) as the prosthetic group.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Aorta, Thoracic: The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.Angiotensin II: An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Hypochlorous Acid: An oxyacid of chlorine (HClO) containing monovalent chlorine that acts as an oxidizing or reducing agent.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Electron Transport Complex III: A multisubunit enzyme complex that contains CYTOCHROME B GROUP; CYTOCHROME C1; and iron-sulfur centers. It catalyzes the oxidation of ubiquinol to UBIQUINONE, and transfers the electrons to CYTOCHROME C. In MITOCHONDRIA the redox reaction is coupled to the transport of PROTONS across the inner mitochondrial membrane.Electron Transport: The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)Sodium Azide: A cytochrome oxidase inhibitor which is a nitridizing agent and an inhibitor of terminal oxidation. (From Merck Index, 12th ed)Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Mitochondria, Heart: The mitochondria of the myocardium.Glucose Oxidase: An enzyme of the oxidoreductase class that catalyzes the conversion of beta-D-glucose and oxygen to D-glucono-1,5-lactone and peroxide. It is a flavoprotein, highly specific for beta-D-glucose. The enzyme is produced by Penicillium notatum and other fungi and has antibacterial activity in the presence of glucose and oxygen. It is used to estimate glucose concentration in blood or urine samples through the formation of colored dyes by the hydrogen peroxide produced in the reaction. (From Enzyme Nomenclature, 1992) EC 188.8.131.52.Protein Carbonylation: The appearance of carbonyl groups (such as aldehyde or ketone groups) in PROTEINS as the result of several oxidative modification reactions. It is a standard marker for OXIDATIVE STRESS. Carbonylated proteins tend to be more hydrophobic and resistant to proteolysis.Membrane Potential, Mitochondrial: The voltage difference, normally maintained at approximately -180mV, across the INNER MITOCHONDRIAL MEMBRANE, by a net movement of positive charge across the membrane. It is a major component of the PROTON MOTIVE FORCE in MITOCHONDRIA used to drive the synthesis of ATP.Deferoxamine: Natural product isolated from Streptomyces pilosus. It forms iron complexes and is used as a chelating agent, particularly in the mesylate form.Penicillamine: 3-Mercapto-D-valine. The most characteristic degradation product of the penicillin antibiotics. It is used as an antirheumatic and as a chelating agent in Wilson's disease.Arterioles: The smallest divisions of the arteries located between the muscular arteries and the capillaries.Arginine: An essential amino acid that is physiologically active in the L-form.Reperfusion Injury: Adverse functional, metabolic, or structural changes in ischemic tissues resulting from the restoration of blood flow to the tissue (REPERFUSION), including swelling; HEMORRHAGE; NECROSIS; and damage from FREE RADICALS. The most common instance is MYOCARDIAL REPERFUSION INJURY.Diabetes Mellitus, Experimental: Diabetes mellitus induced experimentally by administration of various diabetogenic agents or by PANCREATECTOMY.Glutathione Disulfide: A GLUTATHIONE dimer formed by a disulfide bond between the cysteine sulfhydryl side chains during the course of being oxidized.Ubiquinone: A lipid-soluble benzoquinone which is involved in ELECTRON TRANSPORT in mitochondrial preparations. The compound occurs in the majority of aerobic organisms, from bacteria to higher plants and animals.Vasoconstrictor Agents: Drugs used to cause constriction of the blood vessels.Nitroso CompoundsAcetylcysteine: The N-acetyl derivative of CYSTEINE. It is used as a mucolytic agent to reduce the viscosity of mucous secretions. It has also been shown to have antiviral effects in patients with HIV due to inhibition of viral stimulation by reactive oxygen intermediates.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Apoenzymes: The protein components of enzyme complexes (HOLOENZYMES). An apoenzyme is the holoenzyme minus any cofactors (ENZYME COFACTORS) or prosthetic groups required for the enzymatic function.NAD: A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)Chelating Agents: Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.Cell Death: The termination of the cell's ability to carry out vital functions such as metabolism, growth, reproduction, responsiveness, and adaptability.Adrenochrome: Pigment obtained by the oxidation of epinephrine.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.Luminescence: Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Luminol: 5-Amino-2,3-dihydro-1,4-phthalazinedione. Substance that emits light on oxidation. It is used in chemical determinations.Anaerobiosis: The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Endothelial Cells: Highly specialized EPITHELIAL CELLS that line the HEART; BLOOD VESSELS; and lymph vessels, forming the ENDOTHELIUM. They are polygonal in shape and joined together by TIGHT JUNCTIONS. The tight junctions allow for variable permeability to specific macromolecules that are transported across the endothelial layer.Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.Salicylates: The salts or esters of salicylic acids, or salicylate esters of an organic acid. Some of these have analgesic, antipyretic, and anti-inflammatory activities by inhibiting prostaglandin synthesis.Oxyhemoglobins: A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.PhosphoproteinsBiomimetic Materials: Materials fabricated by BIOMIMETICS techniques, i.e., based on natural processes found in biological systems.Azides: Organic or inorganic compounds that contain the -N3 group.Vasoconstriction: The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.Tumor Necrosis Factor-alpha: Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.Mitochondrial Proteins: Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Calcimycin: An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Mitochondria, Muscle: Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.Sodium Cyanide: A highly poisonous compound that is an inhibitor of many metabolic processes and is used as a test reagent for the function of chemoreceptors. It is also used in many industrial processes.S-Nitroso-N-Acetylpenicillamine: A sulfur-containing alkyl thionitrite that is one of the NITRIC OXIDE DONORS.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.