Kinds Of Photosensitizers Research Articles

Photosensitizer screening from Chinese medicinal herbs and photodynamic anticancer Studies

Objective: To find new photosensitizers from Chinese medicinal herbs for cancer photodynamic therapy.Methods: The extracts of thirteen herbs were examined: (1) Their fluorescence excitation wave lengths and emission wave lengths; (2) Their fluorescence intensity in living cells and (3) Their distribution and localization in the living cells and the fixed cells both stained in each extract, and responses of cell fluorescence intensity to pH value change. Furthermore, the herb’s anticancer photosensitive efficiencies were studied by using BGC823 human stomach cancer cells.Results: Cortex Phellodendri and Rhizoma Coptidis, were found with optimal fluorescence properties as photosensitizers in this test. The latter could remarkably reduce the cell metabolic viability, proliferative ability and increase the cell mortality when the cells exposed to both drugs and luminance but not to drug only.Conclusions: The potential of Chinese medicine as a new kind of photosensitizer and its possibility for using in anticancer photodynamic therapy are existed.

The application of the micronucleus test in Chinese hamster V79 cells to detect drug-induced photogenotoxicity

Recent reports on the photochemical carcinogenicity and photochemical genotoxicity of fluoroquinolone antibacterials led to an increasing awareness for the need of a standard approach to test for photochemical genotoxicity. In this study the micronucleus test using V79 cells was adapted to photogenotoxicity testing. Results of using different UVA/UVB relationships enabled us to identify a suitable irradiation regimen for the activation of different kinds of photosensitizers. Using this regimen, 8-methoxypsoralen and the fluoroquinolones lomefloxacin, grepafloxacin and Bay Y 3118 were identified to cause micronuclei and toxicity upon photochemical activation. Among the phenothiazines tested, chlorpromazine and 2-chlorophenothiazine, were positive for both endpoints, whereas triflupromazine was only slightly photoclastogenic in the presence of strong phototoxicity. Among the other potential human photosensitizers tested (oxytetracycline, doxycycline, metronidazole, emodin, hypericin, griseofulvin), only hypericin was slightly photogenotoxic. Photochemical toxicity in the absence of photochemical genotoxicity was noted for doxycycline and emodin. With the assay system described, it is possible to determine photochemical toxicity and photochemical genotoxicity concomitantly with sufficient reliability.

An argon-dye laser system for photodynamic therapy and diagnosis

An argon-dye laser system for the clinical application of photodynamic therapy and photodynamic diagnosis is presented. Two out-patient treatment rooms and three operating theaters are served by an argon-dye laser system which can be accessed by remote-control from each treatment room. The argon-dye laser offers a wide range of light wavelengths with sufficient energy for all kinds of photosensitizers and fluorescent substances. This report presents our experiences with the first remote-controlled laser configuration which is being used routinely in clinical practice for photodynamic therapy and photodynamic diagnosis. [Neurol Res 1999; 21: 103-107]

Photodynamic Therapy With YAG‐OPO Laser for Early Stage Lung Cancer

Photodynamic therapy (PDT) utilizing Photofrin is proving to be effective for the treatment of early stage lung cancers. The effect of PDT utilizing YAG-OPO laser as new light source was evaluated in 26 patients (29 lesions) with early stage lung cancers. YAG-OPO laser is solid state tunable laser which is easy to change wavelength between 620 and 670 nm exciting various kinds of photosensitizers. Moreover, YAG-OPO laser is more reliable, smaller and has less consumables than argon-dye laser or excimer-dye laser. As the result of PDT with YAG-OPO laser, complete remission (CR) was obtained in 82.6% of the 29 lesions, partial remission (PR) in 13.8% and no change (NC) was obtained in 3.4%. We conclude that PDT utilizing YAG-OPO laser is efficacious in the treatment of early stage lung cancers and can achieve complete remission.