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Proceedings Paper

In-vitro study on ALA-induced endogenous protoporphyrin IX as photosensitizer for photodynamic tumor diagnosis and therapy
Author(s): K. Ueberriegler; D. Fiedler; Thomas Verwanger; Gerlinde Schnitzhofer; E. Banieghbal; Barbara E. Krammer
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Paper Abstract

Photodynamic tumor diagnosis and therapy is efficiently carried out by endogenous protoporphyrin IX as photosensitizer, induced by external addition of the precursor 5-aminolevulinic acid (ALA). In the present study, PpIX localization and photodynamically induced damage was investigated in normal and transformed human fibroblasts. PpIX formation reaches its maximum after incubation for at least 20 h with 700 (mu) g/m1 ALA, and increases with the pH- value. ALA has to be given 20-30 times more than external PpIX in order to produce the same cytotoxic damage. As detected by Low Light Imaging, PpIX is generated in the mitochondria, released to the cytoplasm and distributed to cytoplasma and nuclear membranes.The nucleus is not stained. Intracellular targets of PpIX damage after irradiation are mainly mitochondria, ER and nuclear membrane. The organelles show a decomposition pattern, which resembles apoptotic morphology and occurs faster in the co-cultivated transformed than in the normal cells. ALA-treated hepatocytes produce micronuclei and chromosomal aberrations, which indicates some mutagenic potential. Expression studies of the (proto)oncogenes c-myc and bcl-2 sublethally treated fibroblasts by quantitative RT-PCR show high deviations from the constitutive expression level, which are accompanied by cell cycle disturbances, indicating a possible precursor role to apoptosis introduction.

Paper Details

Date Published: 14 July 1998
PDF: 5 pages
Proc. SPIE 3423, Second GR-I International Conference on New Laser Technologies and Applications, (14 July 1998); doi: 10.1117/12.316627
Show Author Affiliations
K. Ueberriegler, Univ. of Salzburg (Austria)
D. Fiedler, Univ. of Salzburg (Austria)
Thomas Verwanger, Univ. of Salzburg (Austria)
Gerlinde Schnitzhofer, Univ. of Salzburg (Austria)
E. Banieghbal, Univ. of Salzburg (Austria)
Barbara E. Krammer, Univ. of Salzburg (Austria)

Published in SPIE Proceedings Vol. 3423:
Second GR-I International Conference on New Laser Technologies and Applications
Alexis Carabelas; Paolo Di Lazzaro; Amalia Torre; Giuseppe Baldacchini, Editor(s)

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