| oxygen poisoning | A body disturbance resulting from breathing high partial pressures of oxygen; characterised by visual and hearing abnormalities, unusual fatigue while breathing, muscular twitching, anxiety, confusion, incoordination, and convulsions; although the mechanism for development of the condition is obscure, a disruption of enzymatic activity is likely, perhaps as a result of free radical formation. Synonym: oxygen poisoning. (05 Mar 2000) |
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| oxygen radical | <chemistry> Any oxygen species that carries an unpaired electron (except free oxygen). Examples are the hydroxyl radical and the superoxide anion. These radicals are very powerful oxidizing agents and cause structural damage to proteins and nucleic acids. They mediate the damaging effects of ionising radiation. (18 Nov 1997) |
| oxygen radioisotopes | Unstable isotopes of oxygen that decay or disintegrate emitting radiation. O atoms with atomic weights 13, 14, 15, 19, and 20 are radioactive oxygen isotopes. (12 Dec 1998) |
| oxygen tent | A transparent enclosure, suspended over the bed and enclosing the patient, used to supply a high concentration of oxygen. (05 Mar 2000) |
| oxygen therapy | Treatment in which an increased concentration of oxygen is made available for breathing, through a nasal catheter, tent, chamber, or mask. (05 Mar 2000) |
| oxygen toxicity | A body disturbance resulting from breathing high partial pressures of oxygen; characterised by visual and hearing abnormalities, unusual fatigue while breathing, muscular twitching, anxiety, confusion, incoordination, and convulsions; although the mechanism for development of the condition is obscure, a disruption of enzymatic activity is likely, perhaps as a result of free radical formation. Synonym: oxygen poisoning. (05 Mar 2000) |
| oxygen utilization coefficient | The extraction coefficient for oxygen in any given tissue. (05 Mar 2000) |
| epidemiology, molecular | The application of molecular biology to the answering of epidemiological questions. The examination of patterns of changes in DNA to implicate particular carcinogens and the use of molecular markers to predict which individuals are at highest risk for a disease are common examples. (12 Dec 1998) |
| european molecular biology lab gene bank | <molecular biology> A large database of DNA sequence data in Heidelberg, Germany, compiled from international sources. It is the European equivalent to the Genbank DNA sequence databank in the United States of America. WWW: EMbase. (09 Oct 1997) |
| evolution, molecular | Evolution at the molecular level of DNA sequences and proteins. (rieger et al., glossary of genetics: classical and molecular, 5th ed) (12 Dec 1998) |
| kinetic molecular theory | <chemistry> This theory assumes that molecules must collide in order to react. The more collisions the more likely it is for a reaction to occur. However, depending on the conditions, only a small fraction of the collisions are effective in producing a reaction. There are several constraints. In order for a reaction to occur, bonds initially are broken, which requires energy. This energy depends on the type of the reaction and comes from the kinetic energies that the molecules possess before the collision. It is called the activation energy. Increasing the temperature increases the kinetic energies and more collisions will occur. In adition, at a higher temperature a greater number of the reacting molecules might possess an energy equal to or greater than the activation energy. However the molecules must also collide in a specific orientation, called the steric factor in order for a reaction to occur. A reaction will only be successful, if the collision has enough energy to be either equal to or greater than the activation energy and if the orientation of the collision allows for correct bond formation. These factors are in the Arrhenius equation: k = zp The rate constant k is proportional to the Arrhenius factor A. A is the product of the collision frequency z, and the steric factor p. The fraction of collisions with sufficient energy to produce a reaction are in the term of the equation. (09 Jan 1998) |
| kininogen, high-molecular-weight | A plasma protein, molecular weight of 110 kD, that normally exists in plasma in a 1:1 complex with prekallikrein. Hmwk is split by plasma kallikrein to produce bradykinin. The complex is a cofactor in the activation of coagulation factor xii. The product of this reaction, xiia, in turn activates prekallikrein to kallikrein. (12 Dec 1998) |
| kininogen, low-molecular-weight | A protein, molecular weight 50 kD, located in various normal tissues. Upon cleavage by kallikrein or other kallikreins, it forms kallidin. Kallidin, in turn, is converted into bradykinin. (12 Dec 1998) |
| lactacid oxygen debt | That part of an oxygen debt represented by the production of lactic acid by anaerobic glycolysis during exercise and, therefore, by the need to eliminate it by oxidative metabolism during recovery. (05 Mar 2000) |
| fructosyl aminocaproate-oxygen oxidoreductase | <enzyme> Catalyses conversion of amadori products to fructosamine; isolated from pseudomonas Registry number: EC 1.5.3.- Synonym: amadoriase, 1-deoxyfructosyl alkyl amino acid oxidase, fructosyl amino acid oxidase, faod enzyme (26 Jun 1999) |