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Proceedings Paper

Selective gastrointestinal uptake of ALA and its benefits for laserlight-induced fluorescence diagnostics (LIFD) and photodynamic therapy (PDT)
Author(s): Jochen Pressmar; Josef Stern; J. Boehm; B. Kohl; Johannes Gahlen
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Paper Abstract

LIFD and PDT are based on the selective uptake of photosensitizers resp. the selective metabolism of their precursors in malignant tissue. Excitation with laserlight results in fluorescence or phototoxic reactions which can be used for the detection or destruction of colorectal carcinoma and dysplasia. General photosensibilization resulting in an increased photosensitivity of the whole body represents the main side and necessitates avoidance of daylight for days up to weeks. Local application of (delta) - aminolevulinic acid (ALA) may reduce systemic uptake. Rats with DMH induced colorectal cancer were photosensitized for LIFD by oral, intravenous or local application of ALA. Urine concentrations of ALA and porphobilinogen (PBG) representing systemic photosensibilization were determined by two-column chromatography. Local colon application of ALA not only increases the quality of LIFD of colorectal cancer, it also provokes three times lower concentrations of PBG in comparison to oral or intravenous administration and reduces in consequence general photosensibilization.

Paper Details

Date Published: 22 December 1997
PDF: 5 pages
Proc. SPIE 3192, Medical Applications of Lasers in Dermatology, Ophthalmology, Dentistry, and Endoscopy, (22 December 1997);
Show Author Affiliations
Jochen Pressmar, Chirurgische Universitaetsklinik Heidelberg (Germany)
Josef Stern, Chirurgische Universitaetsklinik Heidelberg (Germany)
J. Boehm, Chirurgische Universitaetsklinik Heidelberg (Germany)
B. Kohl, Zentrallabor der Medizinischen Universitaetsklinik and Poliklinik (Germany)
Johannes Gahlen, Chirurgische Universitaetsklinik Heidelberg (Germany)

Published in SPIE Proceedings Vol. 3192:
Medical Applications of Lasers in Dermatology, Ophthalmology, Dentistry, and Endoscopy
Gregory B. Altshuler; Reginald Birngruber; Marco Dal Fante; Raimund Hibst; Herbert Hoenigsmann; Neville Krasner M.D.; Frederic Laffitte, Editor(s)

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