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An organotypic culture assay has been used to assess the biocompatibility and cytotoxicity of an arterial prosthesis developed at the University of Texas-Arlington (the UTA graft) from a structurally modified polyurethane (PU) elastomer (Tecoflex®). The cell culture test was applied to the UTA graft after sterilization by ethylene oxide and by gamma radiation in two separate series. First, small specimens of the prosthesis were incubated for 7 days on a semisolid nutrient medium with their luminal surface in direct contact with endothelium explanted from the aorta of chick embryos. Second, the possibility of cytotoxic contaminants being leached from the polyurethane was assessed by immersing the biomaterial in the liquid culture medium for 5 days at 37°C prior to conducting the organo-typic culture assay on a standard control surface.The structure of the UTA polyurethane prosthesis is porous, but the graft wall is impervious because it contains closed (i.e., noncommunicating) pores. In addition, four other vascular prostheses were included in the study for comparison. They were the Hydrophilic Mitrathane® PU graft with a similar impervious, closed pore structure, an experimental Hydrophobic Mitrathane® PU graft with a fibrous, open pore structure, and the commercial Impra® and Reinforced Goretex® expanded PTFE grafts.Following 7 days of cell culture, the biocompatibility and cytotoxicity of the various biomaterials were measured in terms of the area of migrating cells, the density of cells surrounding the explants, and the level of cell adhesion. Comparison of the results against control cultures demonstrated that the UTA graft, along with the other four prostheses, does not release cytotoxic extractables. Microscopic observations of its cultured surface indicated that the UTA graft promotes a high density of cell growth over a limited area, similar to the Hydrophilic Mitrathane® graft. This level of biocompatibility is considered inferior to that of the two PTFE and the Hydrophobic Mitrathane® prostheses, which promote more extensive cell migration, greater cell adhesion, and cell growth in a continuous single layer.

Ceramic composites made of a core of dense titania and a surface of porous tricalcium phosphate granules were prepared using a three-stage process of slip casting, pre-sintering, and co-sintering. A cytocompatibility study has shown that the composites might offer potential for medical applications.

Electrically conducting polypyrrole-treated films have recently been shown to influence the morphology and function of mammalian cells in vitro. This type of polymer represents a possible alternative biomaterial for use in vascular implantation. The present study compared the in vitrobiocompatibility of five different polyester woven fabrics having increasing levels of electrical conductivity ranging from 4.5 × 104to 123 O/square with that of low density polyethylene and polydimethylsiloxane primary reference materials. Biocompatibility was measured in terms of four different types of in vitrocellular response, including (a) an indirect and (b) a direct control organotypic culture assay using endothelial cells, (c) a polymorphonuclear (PMN) cell activation study using flow-cytometric measurements of CD11/CD18integrin molecule expression, and (d) a semiquantification of interleukin (IL)-6 mRNA expression on monocytes/macrophages using reverse-transcriptase polymerase chain reaction. The organotypic culture study revealed that the fabrics with high levels of conductivity exhibited lower cell migration, proliferation, and viability. The PMN activation study of blood from 10 healthy adult donors demonstrated that the two most conductive fabrics were able to identify the more reactive donors. The levels of IL-6 mRNA expression by monocytes/macrophages decreased as the conductivity level of the fabrics increased. The results of the present study therefore indicate that high levels of conductivity (<200 O/square) on polyester fabrics are detrimental to the growth, migration, and viability of endothelial cells; induce elevated PMN activation; and affect the intracellular metabolism of monocytes. They also point to a specific range of conductivity (103< 104O/square) which is associated with an optimum in vitrocellular response. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 41, 519–526, 1998.

Cell adhesion and spreading of chick embryo vascular and corneal explants grown on rough and smooth poly (methyl methacrylate) (PMMA) were analyzed to test the cell response specificity to substratum surface properties. Different degrees of roughness were obtained by sandblasting PMMA with alumina grains. Hydrophilic and hydrophobic components of the surface free energy (SFE) were calculated according to Good-van Oss's model. Contact angles were determined using a computerized angle meter. The apolar component of the SFE, ?sLW, increased with a slight roughness whereas the basic component, ?s-, decreased. The acido-basic properties disappeared as roughness increased. Incubation of PMMA in culture medium, performed to test the influence of the biological environment, allowed surface adsorption of medium proteins which annihilated roughness effect and restored hydrophilic properties. An organotypic culture assay was carried out in an attempt to relate the biocompatibility to substratum surface state. Cell migration was calculated from the area of cell layer. Cellular adhesion was determined by measuring the kinetic of release of enzymatically dissociated cells. A slight roughness raised the migration area to an upper extent no matter which cell type. Enhancement of the cell adhesion potential was related to the degree of roughness and the hydrophobicity. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 36, 99–108, 1997.

Gelatin or a mixture of albumin and gelatin has been proposed for the coating of vascular grafts according to their surface thrombogenicity and biocompatibility, and the possibility of biodegradation. Heparin treatment of hemocompatible surfaces improved the patency of prostheses. In this study, different amounts of heparin were immobilized on these protein gels using a water-soluble carbodiimide [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide]. The results showed a coupling of heparin with gelatin and/or albumin at the surface of the gels, stable for as long as 1 month. From 0.20 to 3.60 µg · cm-2, heparin could be immobilized. The antiproliferative activity of immobilized heparin was controlled toward bovine smooth-muscle cells grown on these gels. Cell growth inhibition was dose dependent, but the percentages of inhibition were lower at day 8 than at day 4 at any heparin concentration used under experimental conditions. Referring to heparin in solution, immobilized heparin displayed an antiproliferative activity that improved the potential interest for coating. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 446–452, 1998.

Myxalin is a glycopeptide extracted recently from a gram-negative bacterium. It has blood anticoagulant properties and can enhance endothelial cell growth. With the ultimate objective of using this bioactive molecule to promote vascular graft healing, this study assessed its biocompatibility in vivo by comparing the cellular and immunological responses of gelatin-coated knitted polyester grafts with and without myxalin following implantation in the peritoneal cavity of rats for prescheduled periods of 3 days and 1, 2, and 4 weeks. A nongelatin-coated virgin polyester graft was included as the reference material. The biological response to gelatin alone was characterized by a slower rate of cellular infiltration into the implant, reduced collagen synthesis, and higher levels of acid phosphatase and esterase activity in the surrounding tissue. The addition of myxalin to this coating resulted in a significant reduction of hydrolase secretion in the tissue surrounding the implant and an enhancement of cellular ingrowth.

L’Agence nationale d’appui à la performance (ANAP) a développé l’outil « Autodiag » permettant de conduire un diagnostic du fonctionnement de la stérilisation par une étude de coût. Pour chaque type de composition, cet outil donne un coût calculé à partir de l’ensemble des informations collectées sur la stérilisation. Les valeurs calculées sont ainsi intégrées dans une étude de coût du passage à l’usage unique (UU) des pinces de Magill des chariots d’urgence. Le passage de ces pinces, actuellement restérilisées, à leur équivalent en UU non stériles a été validé par l’équipe opérationnelle d’hygiène et les réanimateurs.