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9 July 2001 Approach toward characterizing the fraction of all oxidation events that attack a particular site within cells during PDT
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Proceedings Volume 4257, Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical; (2001) https://doi.org/10.1117/12.434688
Event: BiOS 2001 The International Symposium on Biomedical Optics, 2001, San Jose, CA, United States
Abstract
This paper considers the fraction PDT-induced oxidizing radicals that react with a specific oxidizable target within a cell rather than with all possible oxidizable sites. There are many oxidizable sites within the cell, each with a different efficiency of oxidation (Y_ox_j) and a different in vivo concentration (C_iv_j). One measures the efficiency of oxidation of a single ith chemical species in vitro (Y_it_i), then measures the oxidation of the same species in vivo (Y_iv_i). The concentration of this ith species in vivo must be measured (C_iv_i). A convenient test chemical species is chosen, such as a photobleachable fluorophore. Then the in vivo yield is approximately: Y_iv_i = (C_iv_i*Y_it_i)/sum_all_j(C_iv_j*Y_iv_j) (eq.1). Rearranging to solve for the total oxidation: Sum_all_j(C_iv_j*Y_iv_j) = (C_iv_i*Y_it_i)/Y_iv_I (Eq.2) Once the sum_all_j() in Eq.2 is specified, one can measure the in vitro oxidation efficiency and the in vivo concentration of any ith species and use Eq.1 to predict the fraction of PDT_generated singlet oxygen that will attack that ith species in vivo. Of course, the above is only a first approximation toward a complex problem but is a beginning. This paper illustrates the experimental specification of the Y_ox_j for NADPh oxidation in a cuvette using the photosensitizer Photofrin.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Steven L. Jacques and Paulo R. Bargo "Approach toward characterizing the fraction of all oxidation events that attack a particular site within cells during PDT", Proc. SPIE 4257, Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical, (9 July 2001); https://doi.org/10.1117/12.434688
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