Studies on the mechanism of chemical radioprotection by dimethyl sulphoxide

Journal Article · Thu Nov 01 00:00:00 EST 1973 · Int. J. Radiat. Biol., v. 24, no. 5, pp. 533-536

DOI:https://doi.org/10.1080/09553007314551431· OSTI ID:4375626

Reuvers, A P; Greenstock, C L; Borsa, J; Chapman, J D

Measurements were made of rate constants for the reaction of OH with DMSO (dimethyl sulfoxide) and various other radioprotectors. Pulse radiolysis experiments were made with a 4-MeV Van de Graaf generator delivering 50-nsec electron pulses in the range 0.5 to 5 Krads, using competition kinetics with ferrocyanide and thiocyanate as competitive solutes. Rate constants for the reactions of OH with the following compounds were determined:- N-amyl alcohol, isoamyl alcohol, phenethyl alcohol, isobutanol, glycerol, inositol, ribose, DMSO, tertbutanol, ethanol, isopropanol. The rate constant for the reaction of eaq/sup -1/ with DMSO was also measured and found to be less than 10/sup 7/M/sup -1/s/sup -1/. The rate constants were also determined in a steady state radiation- chemical system, using DNA as the radiation target for radiosensitizer binding to nitrofurazone. The following OH scavengers were found to inhibit the amount of radioactivity bound to the DNA, inhibition increasing with increasing scavenger concentration, but being independent of sensitizer concentration: tert-butanol, ethanol, isopropanol, isobutanol, isoamyl alcohol, DMSO. A comparison of the two sets of data showed good correlation for the alcohols, but the value obtained for K/sub OH+DNA/ = 3 x 10/sup 8/M/sup -1/s/sup -1/ was lower than the rate constant of 5.2 x 10/sup 8/M /sup -1/s/sup -1/ determined with pulse radiolysis by the authors previously STAChapman, J. D. et al., Radiat. Res. 53, 190 (1973)!. It is suggested that the results for DMSO indicate that either DMSO is more effective in competing for OH with DNA than it is with low molecular weight solutes, or that its absolute rate-constant with OH is ~ 1.2 x 10/sup 10/ M/sup - 1/ s/sup -1/. (UK)

• Research Organization: Atomic Energy of Canada Ltd., Pinawa, Manitoba
• NSA Number: NSA-29-012571
• OSTI ID: 4375626
• Journal Information: Int. J. Radiat. Biol., v. 24, no. 5, pp. 533-536, Other Information: Orig. Receipt Date: 30-JUN-74; Bib. Info. Source: UK (United Kingdom (sent to DOE from))
• Country of Publication: United Kingdom
• Language: English

Related Subjects

N40300* -Chemistry-Radiation Chemistry
*BUTANOLS- RADIOSENSITIVITY EFFECTS
*DMSO- RADIOSENSITIVITY EFFECTS
*DNA- BIOLOGICAL RADIATION EFFECTS
*ETHANOL- RADIOSENSITIVITY EFFECTS
*GLYCEROL- RADIOSENSITIVITY EFFECTS
*HYDROXYL RADICALS- CHEMICAL REACTION KINETICS
*INOSITOL- RADIOSENSITIVITY EFFECTS
*PENTANOLS- RADIOSENSITIVITY EFFECTS
*PROPANOLS- RADIOSENSITIVITY EFFECTS
*RIBOSE- RADIOSENSITIVITY EFFECTS
*SOLVATED ELECTRONS- CHEMICAL REACTION KINETICS
AROMATICS
COMPARATIVE EVALUATIONS
DILUTION
ELECTRONS
FERROCYANIDES
HETEROCYCLIC COMPOUNDS
MEV RANGE 01-10
MOLECULAR WEIGHT
PULSED IRRADIATION
RADIOLYSIS
RADIOPROTECTIVE SUBSTANCES
SCAVENGING
SEMICARBAZON