Continuum of light sensitivity in atopic dermatitis: A retrospective analysis of 139 cases in Scotland.

Background: Previous reports have characterized photosensitivity in atopic dermatitis (AD), but with differences in terminology and criteria.

Objective: This study aims to assess outcomes in 139 patients with AD referred for photodiagnostic testing and to establish diagnostic criteria for photosensitivity in AD.

Methods: Clinical and photodiagnostic data were reviewed, categorizing photosensitivity into photoexacerbated AD, photosensitive AD, and chronic actinic dermatitis.

Daylight photodynamic therapy in Scotland.

Chronic sun-induced dysplastic skin changes (actinic keratoses) are extremely common in fair-skinned people in Scotland. These changes are a major cause of morbidity and may develop into skin cancer. Actinic keratoses are often extensive and pose a therapeutic challenge as field-directed treatment is required for chronic disease management.

An investigation of the fluorescence induced by topical application of 5-aminolaevulinic acid and methyl aminolaevulinate at different body sites on normal human skin.

Background: Although discovered over a century ago it is only in the last 25 years that photodynamic therapy (PDT) has been the focus of intense research. This versatile treatment modality has been shown to be effective in treating a wide variety of malignancies, and with the increasing incidence of non-melanoma skin cancer (NMSC) is a recognised treatment in dermatology clinics worldwide. There is little known as to whether different body sites influence the uptake and conversion of 5-aminolaevulinic acid (ALA) or methyl aminolaevulinate (MAL) to protoporphyrin IX (PpIX).

A time course investigation of the fluorescence induced by topical application of 5-aminolevulinic acid and methyl aminolevulinate on normal human skin.

Background: Treatment of non-melanoma skin cancers (NMSC) with topical photodynamic therapy (PDT) is a treatment of choice for many clinicians. The two most commonly used PDT photosensitizer precursors are 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL). Current PDT treatment regimes advise longer (4-6 h) application times for ALA and shorter times (3 h) for MAL.

Does surface preparation alter ALA uptake in superficial non-melanoma skin cancer in vivo?

Background/purpose: Photodynamic therapy (PDT) using aminolaevulinic acid (ALA) is widely used in the treatment of non-melanoma skin cancer. Surface preparation of the lesion is commonly performed before application of ALA but the extent of the preparation varies from centre to centre and there has been no study of its effects. The purpose of this study was to examine the effects of surface preparation on the local uptake of ALA by recording fluorescence from accumulated protoporphyrin IX (PPIX).

Fluorescence induced by aminolevulinic acid and methyl aminolevulinate on normal skin.

Background: PDT is a treatment modality, which uses a combination of a photosensitising drug, oxygen and light to selectively destroy pre-malignant and malignant tissue. The most commonly used PDT photosensitiser precursor is 5-aminolevulinic acid (ALA). However recently the introduction of methyl aminolevulinate (MAL) another topical photosensitiser has posed the question of which may be of greater clinical advantage when used in PDT.

The pH-dependent conformational transition of beta-lactoglobulin modulates the binding of protoporphyrin IX.

We have investigated the interaction between PPIX and beta-lactoglobulin (beta-lg) as a function of the pH of the solution. beta-lg is a small globular protein (MW approximately 18 kDa) with a very well characterized structure that reveals several possible binding sites for ligands. The interaction with beta-lg affects the photophysical properties of PPIX.

Characterization of the photoproducts of protoporphyrin IX bound to human serum albumin and immunoglobulin G.

Clinically useful photosensitisers (PSs) are likely bound to subcellular and molecular targets during phototherapy. Binding to a macromolecule has the potential to change the photophysical and photochemical characteristics of the PSs that are crucial for their phototoxicity and cell-killing activity. We investigated the effects of binding of a specific PS (protoporphyrin IX or PPIX) to two proteins, human serum albumin (HSA) and a commercially available immunoglobulin (IgG).