We removed the tracheas from sacrificed laboratory animals and subjected this tissue to multi-step chemical processing. This method allowed us to preserve the cartilage and reduce its antigenicity, thus creating a bioprosthesis very similar to the host tissue. By using allogeneic and xenogeneic prostheses so prepared, no signs of immune rejections were seen following heterotopic or orthotopic implantations. The transplanted cartilage remained stable for periods ranging up to 21 weeks in recipient rats, while partial morphologic integrity of the cartilage was seen up to 1 year in pigs. Reepithelialization of the transplant with ciliated epithelium was completed in all specimens 12-24 weeks following surgery. Segmental replacement of up to one third of the whole trachea was possible in rats, whereas similar segmental replacements failed in pigs. We also found that successful reconstruction of window-shaped defects was possible. We consider our tracheal bioprosthesis to be superior to cialit-preserved grafts and also to most other biological reconstruction procedures.
Summary. In 30 patients with varicosis intermittent high-pressure compression of the leg was applied before a stripping operation and the fibrinolytic activity of intraoperatively obtained vein segments was studied histochemically. In comparison with 10 non-treated patients the fibrinolytic activity of the vessel wall was markedly increased. The systemic enhancement of fibrinolysis was only seen when the blood was drawn from the treated extremity. In addition, after active exercise, i.e. moutaineering and cross-country skiing under competition conditions, a significant activation of fibrinolysis and coagulation was seen in the plasma of the volunteers.
Allogeneic and xenogeneic biological tendon and ligament materials for ligament replacement were tested in the knee of rabbits and sheep. In-vitro and ex-vivo biomechanical tests as well as micromorphological investigations following implantation were performed. The preparation procedure mainly consists in cross linking of collagen by dicarboxylic acids (DC). Modifications in the method induce changes in the biomechanical stability also after implantation. Sheep with autologous patellar tendons substitutions and glutaraldehyde (GA) fixed bovine tendons served as controls. Because of biocompatibility reasons the later seem to be not yet suitable for clinical applications. The DC-tendons need for improved midterm stability prior to clinical implantations; the biocompatibility appears to be excellent.
Laser energy of a Nd-YAG laser (1064 nm. wave length, 8 nsec pulse duration) was directed against various tissue cultures and the urothelium of the ureter, bladder and kidney parenchyma in pigs. Single pulse energy was 50 to 120 mJ with a repetition rate of 20 Hz. Urothelium and kidney parenchyma were irradiated in seven pigs. Tissue samples were examined histologically and electron microscopically directly, two, four, eight and 12 days after irradiation. No macroscopic lesion could be found. Maximum energy caused a small 'rupture cone' of 40 micron. depth. No thermic effects or necrosis resulted, so that no harm is to be expected with unintentional irradiation during laser stone disintegration.
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