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EARLY BIOCHEMICAL RESPONSES TO PHOTODYNAMIC THERAPY MONITORED BY NMR SPECTROSCOPY
Author(s) -
Hilf Russell,
Gibson Scott L.,
Penney David P.,
Ceckler Toni L.,
BRYANT Robert G.
Publication year - 1987
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1987.tb04852.x
Subject(s) - photodynamic therapy , hematoporphyrin , porphyrin , chemistry , oxidative phosphorylation , nuclear magnetic resonance spectroscopy , mitochondrion , cytotoxicity , enzyme , photosensitizer , cancer research , biophysics , biochemistry , nuclear magnetic resonance , biology , photochemistry , in vitro , stereochemistry , physics , organic chemistry
Studies directed at determining the biochemical events that lead to tumor cytotoxicity following photodynamic therapy, a promising new approach for treatment of neoplasia, have demonstrated that exposure of R3230AC mammary tumors to hematoporphyrin derivative or Photofrin II plus visible light caused marked impairment of mitochondrial enzymes functioning in oxidative phosphorylation and electron transport. 31 P‐NMR spectroscopy has now demonstrated that a rapid and striking decrease in NTP (ATP) levels, concomitant with a marked increase in P ; , occurs in tumors shortly after photodynamic therapy. These effects appear to be fluence related. Possible changes in tumor vascularity, as detected by 2 H‐NMR measurements of the uptake of D 2 0, were not observed under the conditions studied. Taken together with our earlier results, we conclude that the reduction in tumor ATP levels in situ , probably via inhibition of mitochondrial function, is a direct and early response of neoplastic tissue to porphyrin‐induced photosensitization.