Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
Autori: Ion, R.-M., Grigorescu, M., Scarlat, F.S., Niculescu, A.V., Niculescu, V., Gunaydin, K.
Editorial: Journal of B.U.ON., 5(2), p.201-207, 2000.
Purpose: This paper deals with the experimental results of the modifying effects of ionizing radiation (electron beam and photons) and/or light on 5,10,15,20-tetra (4-sulfophenyl) porphyrin (TS4PP) in water, dimethylsulfoxide (DMSO) and their binary mixture, as solvents. Also, the incorporation of this porphyrin into human lymphocytes and granulocytes as one of the most important aspects of the photodynamic therapy of cancer, is presented. Materials and methods: The experiments were carried out in water, DMSO and their binary mixture, and at different intensities of ionizing radiation and/or light. The active species shown in this paper were detected, isolated and characterized by ultraviolet-visible (UV-Vis) infrared (IR) and fluorescence techniques. Results: The spectral changes upon photon or electron irradiation of the TS4PP showed the formation of species (phlorin-type) with a strong absorption near 700 nm. When these irradiated porphyrin solutions were exposed to light or high temperature or were kept in the dark, H- and J-aggregated species were generated. The photons (only 800 R) stimulated the H-aggregation and the electron beam (100-200 R) the J-aggregation. Conclusion: Porphyrins may have potential applications in the photodynamic therapy (PDT) of tumours. They produce necrosis of different incipient forms of cancers due to their singlet oxygen capacity. This capacity is enhanced if face-to-face configurations (H-aggregates) are formed. TS4PP as J-aggregate fluorescent form has an increased penetration capacity into human blood cells, higher for granulocytes than for lymphocytes.
Cuvinte cheie: Aggregation; Cytofluorimetry; Ionization; Photochemistry; Photodynamic therapy; Porphyrins