Point fluorescence measurements of transformed tissues using 2-[1-hexyloxyethel]-2-devinyl pyropheophorbide-a

Recently, a new photosensitizer, 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-1 (HPPH) was developed for PDT which possesses more rapid clearance from skin and greater cytotoxicity per drug dose than Photofrin. The spectral characteristics of HPPH shows an absorption band at 665 nm (50,000 M-1cm(superscript -1 and peak emission at 680 nm. The aid of this study was to examine HPPH as a fluorescent diagnostic compound for the detection of transformed tissues using the in vivo fluorescence photodetector. The model of tissue transformation was the carcinogen (DMBA [9, 10-dimethyl-1, 2- benzanthracene])-induced premalignant and malignant lesions of the hamster buccal cheek pouch. The results demonstrated significant correlations between fluorescence levels and histological developments at all time points after injection. Time course studies of HPPH showed highest fluorescence readings at 48 hours after injection of 0.5 mg/kg HPPH (mild-moderate dysplasia, 0.35 +/- 0.17 volts; papillary disease with severe dysplasia, 0.58 +/- 0.33 volts; and squamous cell carcinoma, 1.04 $OM 0.32 volts). Therefore, it appears that HPPH may be a promising fluorophore for the detection of transformed tissues.

[1]  J. Kennedy,et al.  The nature of the chromophore responsible for naturally occurring fluorescence in mouse skin. , 1988, Journal of photochemistry and photobiology. B, Biology.

[2]  Thomas S. Mang,et al.  Fluorescence detection of tumors: studies on the early diagnosis of microscopic lesions in preclinical and clinical studies , 1991, Photonics West - Lasers and Applications in Science and Engineering.

[3]  T. Mang,et al.  Peptide analogues alter the progression of premalignant lesions, as measured by Photofrin fluorescence. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[4]  J. Eveson,et al.  Animal models of intra-oral chemical carcinogenesis: a review. , 1981, Journal of oral pathology.

[5]  T J Dougherty,et al.  Fluorescence detection of tumors early diagnosis of microscopic lesions in preclinical studies , 1993, Cancer.

[6]  Yang Yuanlong,et al.  Characteristic autofluorescence for cancer diagnosis and its origin , 1987, Lasers in surgery and medicine.

[7]  Harvey Lui,et al.  Monitoring of benzoporphyrin derivative monoacid ring A (BPD-MA) in skin tumors by fluorescence during photodynamic therapy: preliminary observations , 1993, Photonics West - Lasers and Applications in Science and Engineering.

[8]  Ravindra K. Pandey,et al.  Structure/activity relationships among photosensitizers related to pheophorbides and bacteriopheophorbides , 1992 .

[9]  T. Dougherty,et al.  Murine pharmacokinetics and antitumor efficacy of the photodynamic sensitizer 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a. , 1993, Journal of photochemistry and photobiology. B, Biology.

[10]  D. Harris,et al.  Endogenous porphyrin fluorescence in tumors , 1987, Lasers in surgery and medicine.

[11]  T. Mang,et al.  Evaluation of porfimer sodium fluorescence for measuring tissue transformation , 1993, Cancer.