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Proceedings Paper

Quantitative methods for studying the role of free radicals in biology
Author(s): Judit Jakus; Tamas Kriska; Tatjana K. Maximova; Andras Nemeth; Laszlo Korecz; Dezso Gal
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Paper Abstract

The mechanism of the primary sensitization steps in Photodynamic Therapy could be of essential importance concerning the efficiency of the treatment. Besides the well known mechanisms there is a possibility that the interaction between the excited triplet state sensitizer and the doublet state free radicals generated by the cells adds a significant contribution to the overall photodynamic effect. To support this hypothesis the quantification and identification of free radicals would be required. For this purpose chemiluminescence studies and spin trapping seemed to be the most suitable methods due to the extremely short lifetime of free radicals in biological systems. We present data on the kinetics of accumulation of free radicals: (1) by measuring luminol- dependent chemiluminescence of stimulated macrophages both in the absence and in the presence of a free radical inhibitor 3,5 di-tert-butyl-4-hydroxyphenyl propionic acid; (2) by following the production of primary, secondary and tertiary radical adducts using DMPO (5,5-dimethyl-1-pyrroline N-oxide) as spin trapping agent in chemical model systems. The measured data are used to determine the effect of the excited sensitizers on the kinetics of accumulation of free radicals under biological conditions. These results would serve to design new and more effective sensitizers used for therapy based on the triplet-doublet mechanism of action.

Paper Details

Date Published: 3 February 1999
PDF: 12 pages
Proc. SPIE 3563, Photochemotherapy of Cancer and Other Diseases, (3 February 1999); doi: 10.1117/12.339125
Show Author Affiliations
Judit Jakus, MTA (Hungary)
Tamas Kriska, Institute of Chemistry (Hungary)
Tatjana K. Maximova, Institute of Chemical Physics (Russia)
Andras Nemeth, Institute of Chemistry (Russia)
Laszlo Korecz, Institute of Chemistry (Hungary)
Dezso Gal, Institute of Chemistry (Hungary)

Published in SPIE Proceedings Vol. 3563:
Photochemotherapy of Cancer and Other Diseases
Benjamin Ehrenberg; Kristian Berg, Editor(s)

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