Porous polyethylene and proplast

A comparative animal study showed that, after implantation in skull defects in guinea pigs, porous high-density polyethylene (PHDPE) was substantially better anchored in the bone than Proplast, and had greater stability of form and structure. In Proplast, ingrowth of fibrous tissue caused partial structural dilatation and fragmentation, which could limit its suitability for use in reconstructive surgery

Essential fatty acids and their long-chain polyunsaturated metabolites in maternal and cord plasma triglycerides during late gestation

The fatty acid composition of plasma lipids was determined in 41 pairs of mothers and their term infants at time of birth (38-42 postmenstrual weeks) by high-resolution capillary gas-liquid chromatography, Linoleic and alpha-linolenic acids were found at smaller concentrations in cord than in maternal triglycerides, in contrast to strikingly higher proportions of their long-chain polyunsaturated metabolites (IC-PUFA), which indicates a preferential maternofetal transport for certain physiologically important LC-PUFA. While no significant gestational age-dependent changes occurred in maternal plasma triglycerides, the values for most of the fetal long-chain n-3 metabolites increased with the duration of gestation, possibly reflecting an increased transplacental fatty acid passage during late pregnancy or a maturation of desaturation in the fetal liver, Copyright (C) 2000 S. Karger AG, Basel

Fibrinvernetzte Knorpel- und Kunststoffspäne zur Ohrmuschelrekonstruktion

Bei der Ohrmuschelrekonstruktion werden vom Transplantat hohe Formbeständigkeit und gute Verträglichkeit verlangt. Es wurde untersucht, ob diese Forderungen von einem Gemisch aus geraspeltem, konserviertem Knorpel und gerinnungsaktivem Plasmaprotein erfüllt werden, dem durch Einpressen in eine Silikonform die Gestalt einer Ohrmuschel gegeben wurde. Solche Nachbildungen sind formstabil und zeigen histologisch einen dichten Verbund zwischen Knorpelfragmenten und Fibrin. Nach Implantation bei Meerschweinchen und Ratten findet jedoch nach Tagen bis Wochen eine Lysis des Fibrins, Knorpelresorption und Organisation statt, die zum Verlust der Struktur führt. Werden statt Knorpel Kunststoffspäne aus porösem Polyäthylen verwendet, läßt sich die Festigkeit der gepreßten Formen aber deutlich erhöhen. Die histologische Untersuchung dieser Transplantate zeigte nach 35 Tagen eine stabile Einbettung im Bindegewebe, makroskopisch blieben Form und Konsistenz erhalten

Zur Verwendbarkeit von Kunststoffen bei der Rekonstruktion der Ohrmuschel

Four porous synthetics were tested for their applicability as cartilage replacement in the reconstruction of the auricle: teflon velour, filamentous dacron, porous polyethylene and proplast II. After formation of a fold, the implants were sutured into subcutaneous cavities of the abdominal skin of rats or fixed with fibrin adhesive. Histological and scanning-electron-microscopic examinations have so far been performed after 1 and 3 months. Form stability with persistence of the desired skin fold was good when the material was not too thin or too thick. The infection rate was surprisingly low; skin necroses occurred largely in the area of transfixion sutures. The porosity appears to promote adaptation of the skin to the material and to thus counteract an effacement of the skin fold. The best form stability was evidenced by thermoplastic polyethylene, which was thus also chosen for first clinical applications