Multiple large-surface photodynamic therapy sessions with topical or systemic aminolevulinic acid and blue light in UV-exposed hairless mice.

Background: The use of photodynamic therapy (PDT) with topical aminolevulinic acid (ALA) on large skin surfaces has recently been reported for patients with multiple actinic keratoses.

Objective: The current study compared the ability of topical and systemic ALA-PDT as well as topical ALA-PDT with blue light to delay the appearance of UV-induced skin cancer using the hairless mouse as a model.

Methods: Groups of hairless mice were exposed daily to UV radiation and weekly to ALA-PDT.

Repeated exposure to blue light does not improve psoriasis.

Background: Increased endogenous levels of protoporphyrin IX (PpIX) have been reported in the skin of patients with psoriasis. Activation of PpIX with blue light after exogenous topical application of its precursor, aminolevulinic acid, can improve psoriasis. Light activation of endogenous PpIX for the treatment of psoriasis has never been studied.

Photodynamic therapy with toluidine blue in Jurkat cells: cytotoxicity, subcellular localization and apoptosis induction.

Toluidine blue (TBO) is a cationic thiazine dye with an affinity for neoplastic tissues in vivo. The objective of this study was to explore the in vitro photosensitizing potential of TBO and its capacity to induce apoptosis in human leukaemic T cells. Jurkat cells were incubated with TBO for one hour followed by exposure to 11 J cm(-2) of visible light from a slide projector.