Reduced time to skin grafting in chronic wounds using an esterified hyaluronic acid matrix and negative pressure wound therapy.

INTRODUCTION: The use of NPWT and eHAM can aid in the closure of chronic wounds with exposed bone and tendon. OBJECTIVE: The authors examined the time to skin grafting and wound closure in 10 patients after treatment with either NPWT with eHAM (group 1, n = 5) or NPWT without eHAM (group 2, n = 5). RESULTS: The average time to closure was similar between group 1 and group 2 (15.2 weeks vs 14.6 weeks) despite a nearly twofold greater initial wound area. However, the rate of wound closure per week was better in group 1 than in group 2 in terms of both area (9.0 cm2 vs 6.8 cm2) and volume (12.3 cm3 vs 5.4 cm3). In addition, the rate of wound closure per week at skin grafting was better in group 1 than group 2 in terms of both area (4.5 cm2 vs 3.8 cm2) and volume (25.9 cm3 vs 4.1 cm3). All patients in group 1 received skin grafts within 2 to 3 weeks after their second eHAM application. CONCLUSION: The results of this small case series suggest that eHAM has a synergistic effect when used in combination with NPWT for the treatment of chronic wounds with exposed bone and tendon.

Nerve growth factor mRNA expression in the regenerating antler tip of red deer (Cervus elaphus).

Deer antlers are the only mammalian organs that can fully regenerate each year. During their growth phase, antlers of red deer extend at a rate of approximately 10 mm/day, a growth rate matched by the antler nerves. It was demonstrated in a previous study that extracts from deer velvet antler can promote neurite outgrowth from neural explants, suggesting a possible role for Nerve Growth Factor (NGF) in antler innervation. Here we showed using the techniques of Northern blot analysis, denervation, immunohistochemistry and in situ hybridization that NGF mRNA was expressed in the regenerating antler, principally in the smooth muscle of the arteries and arterioles of the growing antler tip. Regenerating axons followed the route of the major blood vessels, located at the interface between the dermis and the reserve mesenchyme of the antler. Denervation experiments suggested a causal relationship exists between NGF mRNA expression in arterial smooth muscle and sensory axons in the antler tip. We hypothesize that NGF expressed in the smooth muscle of the arteries and arterioles promotes and maintains antler angiogenesis and this role positions NGF ahead of axons during antler growth. As a result, NGF can serve a second role, attracting sensory axons into the antler, and thus it can provide a guidance cue to define the nerve track. This would explain the phenomenon whereby re-innervation of the regenerating antler follows vascular ingrowth. The annual growth of deer antler presents a unique opportunity to better understand the factors involved in rapid nerve regeneration.

Surface activity of lysozyme and dipalmitoyl phosphatidylcholine vesicles at compressed and supercritical fluid interfaces.

The surface activities of lysozyme and dipalmitoyl phosphatidylcholine (DPPC) vesicles at aqueous/compressed fluid interfaces are examined via high-pressure interfacial tension measurements using the pendant drop technique. The density and interfacial tension in compressible fluid systems vary significantly with pressure, providing a versatile medium for elucidating interactions between biomolecules and fluid interfaces and a method to elicit pressure-dependent interfacial morphological responses. The effects of lysozyme concentration (0.0008, 0.01, and 1 mg/mL) and pressure (> or = 7 MPa) on the dynamic surface response in the presence of ethane, propane, N2, and CO2 at 298 K were examined. Interfacial lysozyme adsorption reduced the induction phase and quickly led to interfacial tensions consistent with protein conformational changes and monolayer saturation at the compressed fluid interfaces. Protein adsorption, as indicated by surface pressure, correlated with calculated Hamaker constants for the compressed gases, denoting the importance of dispersion interactions. For DPPC at aqueous/compressed or aqueous/supercritical CO2 interfaces (1.8-20.7 MPa, 308 K), 2-3-fold reductions in interfacial tension were observed relative to the pure binary fluid system. The resulting surface pressures infer pressure-dependent morphological changes within the DPPC monolayer.