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

摘要

Abstract: Recently, a new photosensitizer, 2-$LB@1-hexyloxyethyl$RB@-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$+$MIN@1@cm$+$MIN@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 $LB@9, 10-dimethyl-1, 2- benzanthracene$RB)-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 $POM 0.17 volts; papillary disease with severe dysplasia, 0.58 $POM 0.33 volts; and squamous cell carcinoma, 1.04 approximately 0.32 volts). Therefore, it appears that HPPH may be a promising fluorophore for the detection of transformed tissues. !12