Enhanced biological performance of human adipose-derived stem cells cultured on titanium-based biomaterials and silicon carbide sheets for orthopaedic applications.

It is well known that the surface properties of biomaterials may affect bone-healing processes by modulating both cell viability and osteogenic differentiation. In this study we evaluated proliferation and osteogenic differentiation of human adipose-derived stem cells (hASCs) cultured on three prototypes of titanium disks and on thin layers of silicon carbide (SiC-PECVD), a material characterized by a high hardness and wear resistance. Our data indicated that all the tested surfaces supported cell growth, in particular, hASCs seeded on both titanium treated by a double-step etching process (TIT) and titanium modified by two Anodic Spark Deposition processes (TAA) grew better respect to the ones cultured on titanium obtained by KOH alkali etching process on TAA (TAAK). Furthermore, hASCs well colonized SiC-PECVD surface, showing a quite similar viability to cells cultured on plastic (PA). TIT and TAA better supported osteogenic differentiation of hASCs compared to PA, as shown by a marked increase of both alkaline phosphatase activity and calcified extracellular matrix deposition; in contrast TAAK did not positively affect hASCs differentiation. SiC-PECVD did not alter osteogenic differentiation of hASC cells: indeed, ALP and calcium deposition levels were comparable to those of cells cultured on plastic. Furthermore, we observed similar results testing hASCs either pre-differentiated for 14 days in osteogenic medium or directly differentiated on biomaterials. Our study suggests that modifications of titanium surface may improve osteo-integration of implant devices and that SiC-PECVD may represent a valid alternative for the coating of prosthetic devices to reduce wear and metallosis events.

[The role of skin expansion: giant nevi of the hand]. / Il ruolo dell'espansione cutanea nel trattamento dei nevi giganti della mano.

The Authors, after considering the epidemic and evolution of giant nevi, present their surgical protocol for giant melanocitic nevi of the hand. Their experience is based on 2 cases, but the rarity of these lesions of the hand, the reconstructive technique used and the results obtained justify the report in detail. The Authors used in both cases an expanded groin flap to repair the postexcisional wound. Skin expansion allowed both to obtain flaps, which were wide and reliable, and to close primarily the donor areas. The definitive resorption of the subcutaneous fat caused by the expansion allowed to obtain thin and adaptable flaps, which ensured excellent results also in areas of primary functional value, such as the hand. In both cases, the expanded going flap was used to repair the dorsum of the hand. In one case the lateral and medial parts of the fingers were repaired with skin grafts.