Abstract: Photodynamic therapy (PDT) is an official method of therapy and diagnosis of different tumor localization, including nonmalignant disorders. Development of the method allows spreading of its fields of use over other medical applications and one of them is dental medicine. PDT is based on a local treatment of a photoactive drug (photosensitizer) on the pathogenic cells (tumor, bacteria, virus, etc.) followed by irradiation of the target area with a proper wavelength from the visible spectrum. This brings about electron transitions in the molecule to a higher-energy singlet state and finally results in generation of cytotoxic oxygen species, such as singlet oxygen, superoxide ions, and hydroxyl radicals. In biological surrounding, these oxygen species attack the cellular membranes of the biomolecules, which experience oxidation processes that result in cell death. The development of new sensitizers for PDT continues with second and third generation photosensitizers. The present review reports the main PDT sensitizers in respect to antimicrobial PDT and the mechanisms and light sources. Experimental and clinical results of photodynamic complexes with application to dental medicine are presented.

Abstract: A brief overview of the activities and main accomplishments of a three-year project ‘Black Sea Ecotoxicity Assessment (BSEA)’ funded by the Swiss National Science Foundation SCOPES programmå is presented. Much attention is given to elaboration, optimization and combined application of relevant analytical, physicochemical and biophysical approaches to modelling and experimental determination of relevant chemical species, fractions and total amounts of several priority toxic elements, such as As, Cd, Cu, Hg, Ni, and Pb. The most sensitive atomic spectrometric techniques like flame, electrothermal, hydride generation and coldvapour atomic absorption spectrometry, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry, with or without enrichment by vapour generation, hydride trapping, liquid/liquid extraction and solid phase extraction were employed. Emphasis is put on in vivo and in situ measurements and on calibration and quality control issues, among them: in vivo fluorescence for characterization of dissolved organic matter; cell density; particle counting; mild conditions for alkaline solubilization of marine tissue prior to determination of hydride-active fractions with higher toxicological relevance by AAS; hollow fibre permeation liquid membranes (HF-PLM) for free ion contents; diffusive gradients in thin film gels (DGT) for dynamic metal species; asymmetrical flow-field flow fractionation coupled with UV detection; excitation/emission matrix fluorescence spectroscopy; use of ionimprinted polymethacrylic microbeads for preconcentration and speciation of mercury (inorganic, methylated) by cold vapour AAS, etc. An ‘intrinsic element specific speciation interference’ for As in ETAAS was demonstrated. The biouptake, biotransformations and toxicity of arsenic species arsenite, aresenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) on marine green alga Chlorella salina in seawater from the Bulgarian Black Sea coast is evaluated; toxicity towards marine green algae decrease in the order: As(V) ∼ As(III) >> MMA ∼ DMA. Seawater enrichment with phosphate (up to 1.3 mg P l−1) results in a significant reduction of both intracellular As content and toxicity due to As(III) and As(V). The obtained set of data was further used to evaluate the bioavailability of these metals to the microorganisms, which was then compared with experimental results of metal uptake to green microalga Chlorella salina. This is the first study that combines simultaneous in situ use of DGT and HF-PLM with bioassays to provide further insight to the relationship between speciation and bioavailability of Cd, Cu, Ni, and Pb in seawater. Low level of marine pollution of coastal seawater by the examined trace elements at the end of active tourist season in September 2006 and 2007 was measured. Analytical procedures can easily be applied to laboratory practice.