Antibacterial composite coatings of MgB2 powders embedded in PVP matrix.

Three commercial powders of MgB2 were tested in vitro by MTS and LDH cytotoxicity tests on the HS27 dermal cell line. Depending on powders, the toxicity concentrations were established in the range of 8.3-33.2 µg/ml. The powder with the lowest toxicity limit was embedded into polyvinylpyrrolidone (PVP), a biocompatible and biodegradable polymer, for two different concentrations. The self-replenishing MgB2-PVP composite materials were coated on substrate materials (plastic foil of the reservoir and silicon tubes) composing a commercial urinary catheter. The influence of the PVP-reference and MgB2-PVP novel coatings on the bacterial growth of Staphylococcus aureus ATCC 25923, Enterococcus faecium DMS 13590, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, in planktonic and biofilm state was assessed in vitro at 6, 24, and 48 h of incubation time. The MgB2-PVP coatings are efficient both against planktonic microbes and microbial biofilms. Results open promising applications for the use of MgB2 in the design of anti-infective strategies for different biomedical devices and systems.

The biomolecular and ultrastructural basis of epidermolysis bullosa.

Transmission electron microscopy, immunoelectron microscopy, immunofluorescence and antigenic mapping have improved our understanding of the dermo-epidermal junction. We have reviewed some ultrastructural and biomolecular aspects related to the dermo-epidermal junction. In part, they are implicated in the pathogenesis of a group of hereditary disorders characterized by skin fragility, collectively known as epidermolysis bullosa (EB). These disorders could benefit in the near future from a gene therapy approach but at present genetic counseling, prenatal diagnosis and conservative treatment measures offer little real benefit to patients.

Flow cytometry measurements of intracellular Ca2+ in K 562 cells.

The aim of this study is to show the intracellular Ca2+ changes induced by methotrexate, a cell cycle inhibitor, in order to prove the intracellular Ca2+ implication in cell proliferation processes. The fluorescent dye used to measure this parameter is Fluo-3, a fluorescein derivative useful for measuring the kinetics of Ca2+ transitions, waves and oscillations. The alterations of Ca2+ concentration proper to K562 cells have been studied, using methotrexate as a cell activation factor, both as direct effects on the cell response (1-15 minutes), and effects in time (24h.), using methotrexate in the culture medium. The K562 response at Ca2+ level in time remained constant for the cells grown in methotrexate medium, showing a slight increase in the control medium. We proved that methotrexate, a cell cycle inhibitor decreased the cytoplasmatic Ca2+ concentration in K562 cells, soon after adding methotrexate both to T0 and T1.