title: Competition between photobleaching and fluorescence increase of photosensitizing porphyrins and tetrasulphonated chloroaluminiumphthalocyanine.
abstract: The time-dependent fluorescence changes of photosensitizing porphyrins and tetrasulphonated chloroaluminiumphthalocyanine (A1C1SPc) were measured at different intracellular sites using video-enhanced microscopy and image processing. To obtain variations in intracellular fluorescence intensity, different radiant exposures of a Kr+ laser-pumped dye laser were delivered via a 600 microns plastic-clad silica fibre connected to the microscope. During irradiation, competition between photobleaching and fluorescence increase of the different dyes was observed. The porphyrins normally showed photobleaching, which was dependent on the sensitizer and its specific accumulation within the cell. Photobleaching was less pronounced for hydrophilic uroporphyrin than for more hydrophobic dyes. In contrast with an almost exponential decrease in porphyrin fluorescence with increasing light dose, the fluorescence intensity of A1C1SPc significantly increased at the beginning of irradiation, and could be correlated with intracellular deaggregation.
authors.affiliation: Institut für Lasertechnologien in der Medizin, Universität Ulm, F.R.G.
authors.forename: A
authors.initials: A
authors.lastname: Rück
authors.forename: C
authors.initials: C
authors.lastname: Hildebrandt
authors.forename: T
authors.initials: T
authors.lastname: Köllner
authors.forename: H
authors.initials: H
authors.lastname: Schneckenburger
authors.forename: R
authors.initials: R
authors.lastname: Steiner
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004848:Epithelium / Q000378:metabolism / Q000528:radiation effects; D007211:Indoles / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D009685:Nuclear Envelope / Q000378:metabolism / Q000528:radiation effects; D009942:Organometallic Compounds / Q000378:metabolism*; D010777:Photochemistry; D011166:Porphyrins / Q000378:metabolism* / Q000494:pharmacology; D011838:Radiation-Sensitizing Agents / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D011166:Porphyrins; D011838:Radiation-Sensitizing Agents; C052736:chloroaluminum tetrasulfophthalocyanine