Enhanced toxicity of ‘bulk' titanium dioxide compared to ‘fresh' and ‘aged' nano-TiO2in marine mussels (Mytilus galloprovincialis)

Marine bivalves (Mytilus galloprovincialis) were exposed to titanium dioxide (10 mg L-1) either as engineered nanoparticles (nTiO(2); fresh, or aged under simulated sunlight for 7 days) or the bulk equivalent. Inductively coupled plasma-optical emission spectrometry analyses of mussel tissues showed higher Ti accumulation (>10-fold) in the digestive gland compared to gills. Nano-sized TiO2 showed greater accumulation than bulk, irrespective of ageing, particularly in digestive gland (>sixfold higher). Despite this, transcriptional expression of metallothionein genes, histology and histochemical analysis suggested that the bulk material was more toxic. Haemocytes showed significantly enhanced DNA damage, determined by the modified comet assay, for all treatments compared to the control, but no significant differences between the treatments. Our integrated study suggests that for this ecologically relevant organism photocatalytic ageing of nTiO(2) does not significantly alter toxicity, and that bulk TiO2 may be less ecotoxicologically inert than previously assumed.

Polycyclic aromatic hydrocarbons (PAHS) (I): Toxicity, population exposure and involved foods

Food is one of the main exogenous sources of genotoxic compounds. In heated food products, polycyclic aromatic hydrocarbons (PAHs) represent a priority group of genotoxic, mutagenic and/or carcinogenic chemical pollutants with adverse long-term health effects. People can be exposed to these compounds through different environments and via various routes: inhalation, ingestion of foods and water and even percutaneously. The presence of these compounds in food may be due to environmental contamination, to industrial handling and processing of foods and to oil processing and refining. The highest levels of these compounds are found in smoked foods, in seafood which is found in polluted waters, in grilled meats and, to a lesser extent, in vegetable fats and oils. Lower levels of PAHs are found in vegetables and in cereals and its products.

Intercultural competence in the area of drug dependencies

This article takes a multidimensional or biopsychosocial conception of drug dependency as its starting point. Within this analytical framework, we advocate making the intercultural dimension more visible, since it is essential for the design and implementation of integral intervention processes. We propose intercultural competence as a working model that can increase the capacities of institutions and professionals —a particularly important consideration in the case of social work— in order to effectively address the aforementioned cultural dimension. After an extensive review of the scientific literature, we have defined five processes that can contribute to strengthening an institution’s intercultural competence and four processes that can do the same for a professional’s intercultural competence. Though selected for application in the area of drug dependencies, all these processes can also prove useful in improving attention to any other kind of culturally diverse group or person.

Controlled release of a model antibacterial drug from a novel self-lubricating silicone biomaterial

Abstract There is considerable interest in developing medical devices that provide controlled delivery of biologically active agents, for example, to reduce the incidence of device-related infection. Silicone elastomers are one of the commonest biomaterials used in medical device production. However, they have a relatively high coefficient of friction and the resulting lack of lubricity can cause pain and tissue damage on device insertion and removal. Novel silicone cross-linking agents have recently been reported that produce inherently ‘self-lubricating’ silicone elastomers with very low coefficients of friction. In this study, the model antibacterial drug metronidazole has been incorporated into these self-lubricating silicone elastomers to produce a novel bioactive biomaterial. The in vitro release characteristics of the bioactive component were evaluated as a function of cross-linker composition and drug loading. Although conventional matrix-type release kinetics were observed for metronidazole from the silicone systems, it was also observed that increasing the concentration of the cross-linking agent responsible for the lubricious character (tetra(oleyloxy)silane) relative to that of the standard non-lubricious cross-linking agent (tetrapropoxysilane) produced an increase in the metronidazole flux rate by up to 65% for a specified drug loading. The results highlight the potential for developing lubricious silicone medical devices with enhanced drug release characteristics.