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Titolo:
EPR SPIN-TRAPPING STUDY OF THE DECOMPOSITION OF AZO-COMPOUNDS IN AQUEOUS-SOLUTIONS BY ULTRASOUND - POTENTIAL FOR USE AS SONODYNAMIC SENSITIZERS FOR CELL-KILLING
Autore:
MISIK V; MIYOSHI N; RIESZ P;
Indirizzi:
NCI,RADIAT BIOL BRANCH,NIH,BLDG 10,ROOM B3B69 BETHESDA MD 20892 NCI,RADIAT BIOL BRANCH,NIH BETHESDA MD 20892 FUKUI MED SCH,DEPT PATHOL MATSUOKA FUKUI JAPAN
Titolo Testata:
Free radical research
fascicolo: 1, volume: 25, anno: 1996,
pagine: 13 - 22
SICI:
1071-5762(1996)25:1<13:ESSOTD>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOCHEMICAL DECOMPOSITION; HYDROGEN-ATOMS; RADICALS; HEMATOPORPHYRIN; THERMOLYSIS; AZIDE;
Keywords:
FREE RADICALS; AZO COMPOUNDS; ULTRASOUND; SONODYNAMIC THERAPY; SONOSENSITIZATION; EPR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
V. Misik et al., "EPR SPIN-TRAPPING STUDY OF THE DECOMPOSITION OF AZO-COMPOUNDS IN AQUEOUS-SOLUTIONS BY ULTRASOUND - POTENTIAL FOR USE AS SONODYNAMIC SENSITIZERS FOR CELL-KILLING", Free radical research, 25(1), 1996, pp. 13-22

Abstract

Sonodynamic therapy, a promising new approach to cancer treatment, isbased on synergistic cell killing by combination of certain drugs (sonosensitizers) and ultrasound. Although the mechanism of sonodynamic action is not understood, the role of free radicals produced from sonosensitizers by ultrasound is im plicated. In this work, we studied formation of free radicals during the decomposition of several water-soluble azo compounds by 50 kHz ultrasound in aqueous solutions. Using the spin trap 3,5-dibromo-4-nitrosobenzene sulfonate (DBNBS) tertiary carbon-centered radicals from 2,2'-azobis (N,N'-dimethyleneisobutyramidine) dihydrochloride (VA-044), 2-(carbamoylazo)-isobutyronitrile (V-30), and 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) and (. )CH3 radicals from 1,1'-azobis (N,N'-dimethylformamide) (AAMF) were detectedin argon-saturated solutions and the corresponding oxygen-centered radicals (alkoxyl and peroxyl) from VA-044, V-30, and AAPH were identified using the spin trap 5,5'-dimethyl-1-pyrroline-N-oxide (DMPO) in aerated sonicated solutions. No free radicals from 4,4'-dihydroxyazobenzene-3,3'-dicarboxyl acid, disodium salt (DHAB) could be found in eithersystem. While VA-044 and AAPH could also be readily decomposed by heat (42.5 degrees C and 80 degrees C), V-30 decomposition only occurred in the ultrasound-exposed solutions. The most likely mechanism of decomposition of azo compounds by ultrasound is their thermolysis in the heated shell of the liquid surrounding cavitating bubbles driven by ultrasound and/or by pyrolysis inside these bubbles. Experiments using scavengers of (OH)-O-. and H-., which are produced by sonolysis in aqueous solutions, demonstrated that these radicals are not involved in theultrasound-mediated radical production from the azo compounds. Due tothe known cytotoxic potential of free radicals produced from azo compounds, the use of these compounds as ultrasound sensitizers appears tobe a promising approach for sonodynamic cell killing.

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Documento generato il 27/09/20 alle ore 22:31:49