Ear Nose and Throut

implants of Mastic@', Estane@. polypropylene oxide and an HPBElPBT segmented polyether polyester copolymer were qualitatively and quantitatively evaluated, with respect to interaction with mononuclear and multinucleated phagocytes as well as fibrous capsule formation, after implantation at three sites in the rat middle ear. The volume of the phagocyte exudate surrounding the implants, the degree of implant degradation and fragmentation and the thickness of the fibrous capsules were found to be correlated with the implantation site. From these findings, it can be concluded that it is impo~ant to assess the biological performance of a biomaterial at carefully chosen implantation sites.

A bilayered matrix, as an integral part of a cell seeded skin substitute for deep dermal skin injury, is described. The skin substitute has been given a dense top layer, to function as a substrate for keratinocyte culture, and a porous under layer for wound adhesion and to serve as a template for dermal regeneration. This porous under layer may be seeded with dermal fibroblasts for improvement of neodermis formation. The elastomeric hydrogel Polyactive¿, a biodegradable polyether/polyester block copolymer, has been selected as the top layer component and Polyactive or Poly-L-lactide (PLLA) as the constituents of the under layer; this to ensure that the matrix is degradable and fulfils certain mechanical requirements. Polyactive top layers were found to be highly permeable to water vapour (+/-30 g/m -2 h -1 kPa) -1 and to molecules up to 150 kD (human IgG). Tensile properties of the bilayered matrices were to a considerable extent dependent on top layer and under layer composition an...

A previously developed method to improve the interface between hydroxyapatite (HA) and a polyester-ether (Polyactive 70/30) by using polyacrylic acid or poly(ethylene-co-maleic acid) has been applied to HA/Polyactive 30/70 composites noting that polyactive 30/70 contains less polyethylene glycol (PEG) segments and a higher concentration of rigid poly(butylene terephthalate) (PBT) segments. The mobility of the PEG segments is significantly affected by the existence of a high concentration of rigid PBT segments. Our experimental results show that this method is indeed suitable for making HA/Polyactive 30/70 composites. The hydrogen bond/dipole interaction forming ability of the PEG segment is not affected by the existence of relatively large amounts of PBT segments. By using these coupling agents, the mechanical properties of the composite can be significantly improved both in dry and wet states. A fractographical study of the fracture surfaces revealed that the surface modified HA pa...

A method of obtaining an image of buried structures in an object, comprising partially irradiating said object by light of a wavelength that images said buried structure; and obtaining a complementary partial image of said buried structure by light diffused from a non-irradiated image area. According to the method, an image can be obtained while discarding specular reflections of the object. Thus, deeper structures will be better visible. In a further aspect, the invention offers a method of enhancing imaging of buried structures in an object, comprising: analysing said image as a first image in order to detect the edges of said buried structure; obtaining a second image by irradiating said object with a second light that visually images said object; and combining said first and second images for defining edges of said buried structure in said visual image.