Enhanced response of the fricke solution doped with hematoporphyrin under X-rays irradiation

The vials filled with Fricke solutions were doped with increasing concentrations of Photogem®, used in photodynamic therapy. These vials were then irradiated with low-energy X-rays with doses ranging from 5 to 20 Gy. The conventional Fricke solution was also irradiated with the same doses. The concentration of ferric ions for the Fricke and doped-Fricke irradiated solutions were measured in a spectrophotometer at 220 to 340 nm. The results showed that there was an enhancement in the response of the doped-Fricke solution, which was proportional to the concentration of the photosensitizer. The use of such procedure for studying the radiosensitizing property of photosensitizers based on the production of free radicals is also discussed.Tubos de ensaio foram preenchidos com a solução Fricke dopada com Fotogem® em concentrações crescentes; essa hemotoporfirina é utilizada na terapia fotodinâmica. Esses tubos foram irradiados com doses de 5 a 20 Gy. A solução Fricke convencional também foi irradiada com as mesmas doses. As concentrações de íons férricos nas soluções Fricke convencional e dopadas irradiadas foram medidas num espectrofotômetro com comprimento de onda entre 220 e 340 nm. Os resultados mostraram que quando comparado o Fricke convencional com o Fricke dopado irradiado, as amostras dopadas demonstraram um aumento na resposta da dose absorvida que é proporcional a concentração do Photogem® na solução Fricke. Concluímos que esse procedimento pode ser utilizado para propósitos de dosimetria na terapia com radiossensibilizadores

Viability of fibroblasts cultured under nutritional stress irradiated with red laser, infrared laser, and red light-emitting diode

Phototherapy is noninvasive, painless and has no known side effect. However, for its incorporation into clinical practice, more well-designed studies are necessary to define optimal parameters for its application. The viability of fibroblasts cultured under nutritional stress irradiated with either a red laser, an infrared laser, or a red light-emitting diode (LED) was analyzed. Irradiation parameters were: red laser (660 nm, 40 mW, 1 W/cm(2)), infrared laser (780 nm, 40 mW, 1 W/cm(2)), and red LED (637 +/- 15 nm, 40 mW, 1 W/cm(2)). All applications were punctual and performed with a spot with 0.4 mm(2) of diameter for 4 or 8 s. The Kruskal-Wallis test and analysis of variance of the general linear model (p <= 0.05) were used for statistical analysis. After 72 h, phototherapy with low-intensity laser and LED showed no toxicity at the cellular level. It even stimulated methylthiazol tetrazolium assay (MTT) conversion and neutral red uptake of fibroblasts cultured under nutritional stress, especially in the group irradiated with infrared laser (p = 0.004 for MTT conversion and p < 0.001 for neutral red uptake). Considering the parameters and protocol of phototherapy used, it can be concluded that phototherapy stimulated the viability of fibroblasts cultured under nutritional deficit resembling those found in traumatized tissue in which cell viability is reduced. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3602850]FAPEMAT (Mato Grosso Research Support Foundation)[696/2006]FAPEMAT (Mato Grosso Research Support Foundation)[884/2007]FAPESP (Sao Paulo State Research Support Foundation)[2007/08367-0