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Proceedings Paper

Wavelength-dependent in-vitro and in-vivo photodynamic effects after sensitization with 5-aminolevulinic acid induced protoporphyrin IX
Author(s): Rolf-Markus Szeimies; Christoph Abels; Clemens Fritsch; Pia Steinbach; Wolfgang Baeumler; Helmut Messmann; Alwin E. Goetz; Guenter Goerz; Michael Landthaler
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Paper Abstract

Photodynamic therapy (PDT) with topically applied 5-aminolevulinic acid (ALA) is of growing interest, in particular in dermatology. Due to the fact that PDT with intravenously administered Photofrin is the only clinically approved sensitizer so far and is performed at a wavelength of 630 nm, this wavelength is also used in most experimental and clinical trials with ALA. In this study influence of irradiation with coherent light from a tunable dye laser at different wavelengths ranging from 625 to 649 nm was investigated. In in vitro experiments HaCaT immortalized human keratinocytes were sensitized with 30 (mu) g/ml ALA for 24 hrs. By determination of cell viability with the MTT test, best cell-killing effects were observed following irradiation at 635 nm. In an in vivo setting using an amelanotic melanoma (A-Mel-3) grown subcutaneously in Syrian Golden hamsters, these results were confirmed: tumor growth determined by measuring tumor volume increase after 28 days was less pronounced in animals treated with 100 mg/kg ALA i.v. and irradiated 2.5 hrs. later at 635 nm, as compared to animals receiving an equal dose and irradiated at 630 nm. This observation in vitro is probably due to large amounts of photosensitizing protoporphyrin IX (PP) localized in cell membranes which is visualized by confocal laser scanning microscopy (CLSM) and determined by HPLC analysis. These results suggest that in ALA-PDT when a coherent light source is used probably better results are achieved irradiating at 635 nm.

Paper Details

Date Published: 31 January 1996
PDF: 4 pages
Proc. SPIE 2625, Photochemotherapy: Photodynamic Therapy and Other Modalities, (31 January 1996); doi: 10.1117/12.230993
Show Author Affiliations
Rolf-Markus Szeimies, Univ. Regensburg (Germany)
Christoph Abels, Univ. Munchen (Germany)
Clemens Fritsch, Unive. Duesseldorf (Germany)
Pia Steinbach, Univ. Regensburg (Germany)
Wolfgang Baeumler, Univ. Regensburg (Germany)
Helmut Messmann, Univ. Regensburg (Germany)
Alwin E. Goetz, Univ. Munchen (Germany)
Guenter Goerz, Univ. Duesseldorf (Germany)
Michael Landthaler, Univ. Regensburg (Germany)

Published in SPIE Proceedings Vol. 2625:
Photochemotherapy: Photodynamic Therapy and Other Modalities
Benjamin Ehrenberg; Giulio Jori; Johan Moan, Editor(s)

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