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Proceedings Paper

Microscopic studies on aminolevulinic-acid-incubated tumor cells and tumor spheroids
Author(s): Karsten Koenig; Herbert Schneckenburger; Heinrich Walt; Thomas Leemann; Marie-Therese Wyss-Desserich; Angelika C. Rueck; Bruce J. Tromberg
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Paper Abstract

Various microscopy techniques were employed to measure subcellular porphyrin distribution in ALA-incubated tumor cells and tumor spheroids. In addition, photodynamically-induced intracellular changes in morphology and fluorescence were detected. Studies were carried out by confocal laser scanning microscopy, polarization microscopy, video-intensified microscopy, video-enhanced contrast microscopy, time-resolved and time-gated spectroscopy, and spectrally-resolved fluorescence imaging using a tunable liquid crystal filter. It was found that ALA-incubation results in the biosynthesis of protoporphyrin IX (PP IX) in the mitochondria. Long ALA incubation times (>6 h) results in PP IX release to the cytoplasm. PP IX fluorescence has a maximum at 635 nm and a fluorescence decay time of 16 ns. No evidence for the existence of short-lived dimers, aggregates of PP IX, or other porphyrins was found. Cell irradiation resulted in cytotoxic reactions which, in turn, led to mitochondrial swelling followed by destruction of the cell membrane. In addition, PP IX photodestruction and the formation of short-lived chlorin-type photoproducts were observed.

Paper Details

Date Published: 19 July 1994
PDF: 11 pages
Proc. SPIE 2133, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy III, (19 July 1994); doi: 10.1117/12.179990
Show Author Affiliations
Karsten Koenig, Beckman Laser Institute and Medical Clinic and Institute of Lasertechnology in Medicine (Germany)
Herbert Schneckenburger, Institute of Lasertechnology in Medicine and Fachhochschule Aalen (Germany)
Heinrich Walt, Univ. Hospital Zuerich (Switzerland)
Thomas Leemann, Institute of Biomedical Engineering/Univ. and ETH Zuerich (Switzerland)
Marie-Therese Wyss-Desserich, Beckman Laser Institute and Medical Clinic (United States)
Angelika C. Rueck, Institute of Lasertechnology in Medicine (Germany)
Bruce J. Tromberg, Beckman Laser Institute and Medical Clinic (United States)


Published in SPIE Proceedings Vol. 2133:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy III
Thomas J. Dougherty, Editor(s)

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