Hemoporfin-mediated photodynamic therapy for the treatment of port-wine stain birthmarks in pediatric patients

Abstract: Port-wine stain is a type of common congenital superficial telangiectasia in the dermal layer mostly occurring on the forehead, face, and neck. The affected skin shows abnormal red or purple lesions, which darken and thicken. Nodular changes may develop with advancing age. If untreated, port-wine stains scarcely regress, which can have serious lifelong psychological impact on patients and affect their quality of life. In this report, we focused on two cases of port-wine stain in pediatric patients; the youngest patient was only 1.5 years old. During and after treatment, Hemoporfin-mediated photodynamic therapy features fewer adverse reactions, short light protection period, easy nursing, and good efficacy.

Terapia fotodinâmica em hiperoxigenaçäo hiperbárica / Photodynamic therapy in hyperbaric hyperoxia

A Terapia Fotodinâmica (PDT) tem-se mostrado uma técnica seletiva promissora no tratamento do câncer. Após injeção intravenosa de um sensibilizador, que é retido por várias horas em células neoplásias, o tecido é irradiado por um laser, e devido a um mecanismo de transferência de energia não radiativa, agentes citotóxicos são produzidos, induzindo as células tumorais à morte. A técnica de hiperoxigenação hiperbárica (HBO) permite elevar o suprimento de oxigênio molecular, nos tecidos tumorais permitindo potencializar a PDT. Para avaliar o efeito combinado (PDT+HBO), desenvolvemos um modelo experimental que consiste na irradiação de tumores sólidos subcutâneos em dorso de ratos.

Photodynamic Therapy (PDT) have been demonstrated a very promising selectivity potential in cancer treatment. After an intravenous infusion of sensitizes, which is retained for severa! hours inside the neoplasic cells, the tissue is irradiated with a laser beam, and due a non-radiactive transfer mechanism, cytotoxic agents are produced, inducing death of the tumor cells. Hyperbaric hyperoxia (HBO) allows the tissues to achieve high supply of molecular oxygen. ln order to evaluate this combined effect of both therapies an experimental model was developed, creating a tumor mass in the dorsal subcutaneous tissue of rats.

A simple in vitro method to detect singlet oxygen and to compare photodynamic activity using alkaline phosphatase.

A simple, sensitive and reliable in vitro method based on photodynamic inactivation of alkaline phosphatase to detect singlet oxygen and for evaluating relative photosensitizing efficiencies of photosensitizers such as hematoporphyrin (Hp) and phthalocyanines has been developed and compared with photobleaching of p-nitroso dimethyl aniline (RNO) and photooxidation of L-tryptophan. Inactivation of alkaline phosphatase is dependent both on light fluence and sensitizer concentration. Scavengers like mannitol and azide anion indicated the involvement of singlet oxygen in the deactivation of alkaline phosphatase, since azide anion provided concentration dependent protection whereas mannitol had no effect and that compared to ordinary water, photoinactivation of alkaline phosphatase was three times higher in 65% D2O. Alkaline phosphatase appears to be resistant to free radical attack (particularly to OH radicals) since hydrogen peroxide alone or in presence of ferrous ions did not reduce the enzyme activity and mannitol or azide anion gave no significant protection when alkaline phosphatase was irradiated with Co-60 gamma rays up to 2 K Gy. With the present method using red light, the chloroaluminium phthalocyanine sulphonates prepared by sulphonation showed higher and the corresponding condensation product lower photodynamic activity; Hp being intermediate and Mn- and Gd-phthalocyanines had no photodynamic activity.