PHOTOSENSITIZED PROCESSES in vivo: PROPOSED PHOTOTHERAPEUTIC APPLICATIONS*

Abstract

Abstract-The use of photosensitizing dyes having intense absorption bands in the 600-900 nm spectral interval opens up new prospects in the field of photochemotherapy, because it allows the illumination of relatively large tissue volumes with no significant damage to photosensitizer-free tissues. Special interest is currently focused on the photodynamic therapy of solid tumors, because of the property of several dyes with a macrocyclic chemical structure (porphyrins, chlorins, phthalocyanines, xanthenes) to accumulate in significant amounts and be retained for prolonged periods of time by neoplastic lesions. Strategies are being developed for enhancing the selectivity of tumor targeting by photosensitizers through the exploitation of functional or biochemical differences between normal and malignant cells.

A microbiological evaluation of medicinal plants used by the Maya people of Southern Mexico

“…Some photosensitizers such as porphyrins and cyanins have applications in cancer chemotherapy (Jori, 1990), and 8-methoxypsoralen, a furanocumarin which has been used to treat psoriasis and vitiligo in PUVA therapy, has been used successfully by photophoresis in the extracorporeal treatment of leukocytes from patients with cutaneous T-cell lymphomas (Edelson et al, 1987).…”

Photochemical properties of gemifloxacin: A laser flash photolysis study

“…Type I involves direct reaction of the triplet state of the photosensitizer with biomolecules by electron or hydrogen atom transfer. Type II involves energy transfer from the triplet state of the photosensitizer to oxygen to form singlet oxygen [27,28]. However, the mechanisms of phototoxic reactions of 3 GEFX * with biomolecules are not yet examined.…”

PRECLINICAL EXAMINATION OF FIRST and SECOND GENERATION PHOTOSENSITIZERS USED IN PHOTODYNAMIC THERAPY

“…Pharmacologic and photosensitizing responses associated with PDT on neoplastic cells, microvasculature, non-vascular stroma and on circulating components of the blood have been reviewed by Jori (1990), andZhou (1989). Second generation photosensitizers offer potential advantages over Photofrin I1 including chemical purity and a major absorption band at wavelengths greater than 650 nm.…”