Comparison of normal piglet bladder damage after PDT with oral or intravesical administration of ALA.

5-Aminolaevulinic-acid (ALA) can be used as an alternative drug in photodynamic therapy of the bladder, since the selective formation of protoporphyrin IX (PpIX) in the tumour and the virtual absence of induced skin photosensitivity are theoretically advantageous for clinical use. A preclinical study was performed, using an in vivo normal piglet bladder model, in order to determine the maximum drug and light doses for reversible tissue damage. Various ALA doses were administered either orally or instilled in the bladder and different radiant exposures were applied.

Fractionated illumination for oesophageal ALA-PDT: effect on blood flow and PpIX formation.

The effect of fractionating the 633 nm illumination of 5-aminolaevulinic (ALA)-based photodynamic therapy (PDT) of the normal rat oesophagus was studied. Fractionation of the illumination could enhance the PDT effect in two ways: (a) delay of the vascular shutdown or relaxation of the vasoconstriction induced by ALA-PDT and (b) use of newly formed protoporphyrin IX (PpIX), produced during the dark interval. Forty rats were randomly allocated to two groups of 20 animals each.

Fluorescence imaging and spectroscopy of ethyl nile blue A in animal models of (pre)malignancies.

Discrimination between normal and premalignant tissues by fluorescence imaging and/or spectroscopy may be enhanced by a tumor-localizing fluorescent drug. Ethyl Nile Blue A (EtNBA), a dye with no phototoxic activity, was investigated for this purpose. The pharmacokinetics and tissue-localizing properties were investigated in a rat palate model with chemically induced premalignant mucosal lesions (0.

Fractionated illumination in oesophageal ALA-PDT: effect on ferrochelatase activity.

Background And Objective: Administration of 5-aminolevulinic acid (ALA) induces accumulation of the photosensitive compound protoporphyrin IX (PpIX) in certain tissues. PplX can be used as photosensitizer in photodynamic therapy (PDT). More selective or higher PpIX accumulation in the area to be treated could optimize the results of ALA-PDT.

Localisation and accumulation of a new carotenoporphyrin in two primary tumour models.

We have investigated the tumour-localising properties and in vivo fluorescence kinetics of a hexamethoxylated carotenqporphyrin (CP6) in two primary tumour models: UV-B-induced early skin cancer in hairless mice and chemically induced mucosal dysplasia in the rat palate. CP6 fluorescence kinetics are investigated by measuring in vivo fluorescence spectra and images of the mouse skin and the rat palate at different time points after injection. For the tumour-localising properties, microscopic phase-contrast and fluorescence images are recorded.