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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1995-12-8
pubmed:abstractText
A promising new therapeutic modality for skin cancer, administration of the heme precursor 5-aminolevulinic acid followed by light irradiation, is known as photodynamic therapy. Photofrin, the only clinically approved sensitizer, has an absorption maximum at 630 nm, the wavelength used in most experimental and clinical trials with 5-aminolevulinic acid. We investigated photodynamic efficacy of irradiation with coherent light at wavelengths ranging from 622 to 649 nm in vitro and in vivo as well as the content and distribution of intracellular porphyrin after administration of 5-aminolevulinic acid. HaCaT immortalized human keratinocytes were sensitized with 30 micrograms/ml 5-aminolevulinic acid for 24 h in vitro. By cell viability determined with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, the best cell-killing effects were observed after irradiation at 635 nm. Using an amelanotic melanoma (A-Mel-3) grown subcutaneously in Syrian Golden hamsters, we confirmed these results in vivo: tumor growth was markedly delayed in animals treated with 100 mg/kg 5-aminolevulinic acid intravenously and irradiated with coherent light at 635 nm as compared to animals irradiated at 630 nm. This photodynamic effect is probably mediated by large amounts of the photosensitizing porphyrin, protoporphyrin IX, localized in cell membranes as visualized by confocal laser scan microscopy and as determined by high pressure liquid chromatography in vitro. The results suggest that irradiation at 635 nm with a coherent light source is more effective than irradiation at 630 nm for photodynamic therapy with 5-aminolevulinic acid.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-202X
pubmed:author
pubmed:issnType
Print
pubmed:volume
105
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
672-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Wavelength dependency of photodynamic effects after sensitization with 5-aminolevulinic acid in vitro and in vivo.
pubmed:affiliation
Department of Dermatology, University of Regensburg, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't