Biomaterial Database

Reaction of disodium cromoglycate with hydrated electrons. 1988

A J Carmichael, and C M Arroyo, and L G Cockerham

Radiation Sciences Department Armed Forces Radiobiology Research Institute, Bethesda, MD 20814-5145.

A possible mechanism by which disodium cromoglycate (DSCG) prevents a decrease in regional cerebral blood flow but not hypotension in primates following whole body gamma-irradiation was studied. Several studies have implicated superoxide radicals (O2-.) in intestinal and cerebral vascular disorders following ischemia and ionizing radiation, respectively. O2-. is formed during radiolysis in the reaction between hydrated electrons (e-aq) and dissolved oxygen. For this reason, the efficiency of DSCG to scavenge e-q and possibly prevent the formation of O2-. was studied. Hydrated electrons were produced by photolysis of potassium ferrocyanide solutions. The rate constant, k = 2.92 x 10(10) M-1s-1 for the reaction between e-aq and DSCG was determined in competition experiments using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). This spin trap reacts rapidly with e-aq followed by protonation to yield the ESR observable DMPO-H spin adduct. The results show that DSCG is an efficient e-aq scavenger and may effectively compete with oxygen for e-aq preventing the radiolytic formation of O2-..

UI	MeSH Term	Description	Entries
D010782	Photolysis	Chemical bond cleavage reactions resulting from absorption of radiant energy.	Photodegradation
D003497	Cyclic N-Oxides	Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.	Heterocyclic N-Oxides,Cyclic N Oxides,Heterocyclic N Oxides,N Oxides, Cyclic,N-Oxides, Cyclic,N-Oxides, Heterocyclic,Oxides, Cyclic N
D004205	Cromolyn Sodium	A chromone complex that acts by inhibiting the release of chemical mediators from sensitized MAST CELLS. It is used in the prophylactic treatment of both allergic and exercise-induced asthma, but does not affect an established asthmatic attack.	Disodium Cromoglycate,Sodium Cromoglycate,Aarane,Bicromat Spray,Cromoglicic Acid,Cromoglycate,Cromoglycic Acid,Cromolyn,FPL-670,Intal,Lomudal,Nalcrom,Nasalcrom,Opticrom,Vicrom,Acid, Cromoglicic,Acid, Cromoglycic,Cromoglycate, Disodium,Cromoglycate, Sodium,FPL 670,FPL670
D004578	Electron 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.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D004583	Electrons	Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.	Fast Electrons,Negatrons,Positrons,Electron,Electron, Fast,Electrons, Fast,Fast Electron,Negatron,Positron