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Proceedings Paper

Additional approach to PDT: type III mechanism and the role of native free radicals
Author(s): Dezso Gal; Tamas Kriska; Tatiana G. Shutova; Andras Nemeth
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Paper Abstract

It has been suggested by us earlier that interactions of excited triplet sensitizer (3PS) and native free radicals compete with Type I (sensitizer radical mediated) and Type II (singlet oxygen mediated) mechanisms during PDT. Evidence such as fall in the overall radical concentration in vivo ( in mice tumors) during PDT and in the life time of 3PS caused by free radicals supported this assumption In addition, following results have been obtained recently. 1.) Excited Photofrin II and m-THPC affected luminol dependent chemiluminescence (CL) generated by respiratory burst of macrophages like free radical inhibitors. 2.) Quantification of spin trapping for chemical and in vitro systems by kinetic ESR spectrometry yielded detailed knowledge of triplet-doublet interactions 3.)Measurements in open systems (tank reactor) yielded data for the interactions between 3PS and peroxy type radicals 4.)Simulation of experimental data based on mechanisms suggested gave fair agreement. Based on experimental results new PS-s called Antioxidant Carrier Sensiters (ACS-s) have been devised, synthesized and tested one of them showing enhanced activity for PDT.

Paper Details

Date Published: 9 April 2001
PDF: 10 pages
Proc. SPIE 4248, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy X, (9 April 2001); doi: 10.1117/12.424450
Show Author Affiliations
Dezso Gal, Chemical Research Ctr. (Hungary)
Tamas Kriska, Chemical Research Ctr. (Hungary)
Tatiana G. Shutova, Institute of New Materials (Belarus)
Andras Nemeth, Chemical Research Ctr. (Russia)


Published in SPIE Proceedings Vol. 4248:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy X
Thomas J. Dougherty, Editor(s)

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