Bioimpedance for pain monitoring during cutaneous photodynamic therapy: Preliminary study.

Background: Pain is a well-known problem associated with light exposure during topical photodynamic therapy (PDT). Different methods for dealing with the pain have been developed over the past years, ranging from cooling with air or water to nerve blocking. However, the mechanisms responsible for the pain induction have not yet been fully understood.

Microneedle pre-treatment of human skin improves 5-aminolevulininc acid (ALA)- and 5-aminolevulinic acid methyl ester (MAL)-induced PpIX production for topical photodynamic therapy without increase in pain or erythema.

Purpose: To determine the impact of skin pretreatment with microneedles (MNs) on ALA- and MAL-induced protoporphyrin IX (PpIX) production, as well as MN impact on pain sensations during light exposure and erythema after PDT.

Methods: The skin of 14 healthy volunteers was preteated with MNs. Equal amounts of creams containing 2%, 8% and 16% (w/w) ALA and MAL were applied on 1 cm(2) areas for 4 h.

Effect of (R)L-sulforaphane on 5-aminolevulinic acid-mediated photodynamic therapy.

Topical photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA), or so-called ALA-PDT, is a standard procedure in the clinical practice. For optimal treatment of nonmelanoma skin cancer, actinic keratoses and other dermatoses improvements are required because of adverse side effects, which include pruritus, erythema, edema, and pain. (R)L-sulforaphane (SF) is a compound that protects against erythema, but it can also induce DNA fragmentation that leads to cell death by apoptosis.

The effect of lidocaine on PpIX photobleaching and outcome of ALA-PDT in vitro.

Background: Photodynamic therapy (PDT) is based on the light exposure of neoplastic tissue after selective accumulation of photosensitizers in neoplastic cells. One of the major side effects of ALA-PDT is pain during light exposure. Lidocaine is one of several anaesthetics used to relieve this pain.

Biological activity of 5-aminolevulinic acid and its methyl ester after storage under different conditions.

5-Aminolevulinic acid (ALA) is a natural precursor of protoporphyrin IX (PpIX) and heme in cells. Photodynamic therapy (PDT) utilizes a metabolic imbalance in cancer cells, leading to increased PpIX generation from exogenous ALA. Due to chemical instability of ALA in therapeutic concentrations at pH values larger than 5.