Analisi morfologica e molecolare di cellule da colture primarie umane esposte a resine biocompatibili

The cytotoxicity of dental composites has been attributed to the release of residual monomers from polymerized adhesive systems due to degradation processes or the incomplete polymerization of materials. 2-Hydroxyethyl methacrylate (HEMA) is one of the major components released from dental adhesives. Cytotoxic effects due to high concentrations of HEMA have already been investigated, but the influence of minor toxic concentrations for long-term exposition on specific proteins such as type I collagen and tenascin has not been studied in depth. The objective of this project was to study the effect of minor toxic concentrations of HEMA on human gingival fibroblasts (HGFs) and human pulp fibroblasts (HPFs), investigating modification in cell morphology, cell viability, and the influence on type I collagen and tenascin proteins. Different concentrations of the resin monomer and different times of exposition were tested on both cell lines. The cell vitality was determined by MTT assay, and high-resolution scanning electron microscopy analysis was performed to evaluate differences in cell morphology before and after treatment. To evaluate the variability in the expression and synthesis of procollagen α1 type I and tenascin proteins on HGFs and HPFs treated with HEMA at different concentrations immunofluorescence, RT-PCR and western blot analysis, were carried out. The treatments on HGFs with 3mmol/L HEMA, showed a strong reduction of procollagen α1 type I protein at 72h and 96h, demonstrating that HEMA interferes both with the synthesis of the procollagen α1 type I protein and its mRNA expression. The results obtained on HPFs treated with different concentrations of HEMA ranging from 0,5mmol/L to 3mmol/L and for different exposition times showed a strong reduction in cell viability in specimens treated for 96h and 168h, while immunofluorescence and western blotting analysis demonstrated a reduction of procollagen α1 type I and an overexpression of tenascin protein. In conclusion, our results showed that the concentrations of HEMA we tested, effect the normal cell production and activity, such as the synthesis of some dental extracellular matrix proteins.

Web 2.0, contenuti aperti e produzione tra pari: analisi economica delle possibili sinergie.

Analisi in chiave economica e sociale dell'evoluzione di Internet, delle tecnologie legate al Web 2.0, dei fenomeni della pirateria, del software libero ed open source, del copyleft, dei contenuti aperti e della produzione tra pari. Introduzione dei concetti di economia del gratis ("freeconomics") e di coda lunga. Consigli manageriali pratici per i nuovi mercati digitali e per la competizione nella rete Internet.