Preparation and characterization of antimicrobial wound dressings based on silver, gellan, PVA and borax.

Silver-loaded dressings are designed to provide the same antimicrobial activity of topical silver, with the advantages of a sustained silver release and a reduced number of dressing changes. Moreover, such type of dressing must provide a moist environment, avoiding fiber shedding, dehydration and adherence to the wound site. Here we describe the preparation of a novel silver-loaded dressing based on a Gellan/Hyaff(®) (Ge-H) non woven, treated with a polyvinyl alcohol (PVA)/borax system capable to enhance the entrapment of silver in the dressing and to modulate its release. The new hydrophilic non woven dressings show enhanced water uptake capability and slow dehydration rates. A sustained silver release is also achieved. The antibacterial activity was confirmed on Staphylococcus aureus and Pseudomonas aeruginosa.

Macrophage-secreted myogenic factors: a promising tool for greatly enhancing the proliferative capacity of myoblasts in vitro and in vivo.

In this work we set out to determine if the murine macrophage J774 cell line can be used to produce myogenic growth factors. Activated J774 macrophages were grown in serum-free conditions. The macrophage-conditioned medium (MCM) was then used to treat cultures of primary myoblasts and regenerating muscle tissue, in vitro and in vivo respectively. MCM activity in vitro was tested by analyzing the expression of muscle-specific transcription factors, in parallel with the proliferation and differentiation rates of the cells. The macrophage-secreted factors greatly enhanced the proliferative potential of both rat and human primary myoblasts and were found to be highly muscle-specific. In vivo, MCM administration markedly enhanced the regenerative processes in damaged muscles. The ability to produce large amounts of macrophage-secreted myogenic factor(s) in the absence of serum holds great promise for its biochemical characterization and successive application in therapeutic protocols, both for ex vivo gene therapy and for muscle repair.