[Testing bone implants in cell lines and human osteoblasts]. / Testung von Knochenimplantaten auf Zellinien und humanen Osteoblasten.

Two different types of cell-line and fresh human osteoblasts, cultured from cancellous bone grafts from the iliac crest, were used for the study. Three different biomaterials were compared regarding biocompatibility: titanium, steel and hydroxyapatite. The cells were fibroblast cell line (3T3), "osteoblast-like" cell line (MC3T3-E1), and fresh human osteoblasts (HOB) which we cultured in our laboratory. 5 x 10(4) cells of each type were seeded on the three different bone implants. All experiments were performed in triplicate. Cell proliferation and alkaline phosphatase activity were determined 24 and 72 h after the cells were plated on the biomaterials. Human osteoblast growth was better on titanium than on steel and hydroxyapatite. The most remarkable observation was the continuously decreasing alkaline phosphatase activity (ALP) of "osteoblast-like" cells (MC3T3-E1) and human osteoblasts (HOB) on hydroxyapatite. In conclusion, our in vitro observations suggest that the best cell/material interactions were with human osteoblasts (HOB) and titanium.

[Acute venous stasis in the area of the head after bungee-jumping. A report of 2 cases]. / Akute venöse Stase in der Kopfregion durch Bungy-Jumping. Ein Bericht über zwei Fälle.

Jumping from bridges or cranes while secured by an elastic rope is called bungee jumping, and it is an increasingly popular sport. We report on two bungee jumpers who suffered from symptoms of acute venous stasis in the head. These included skin edema, purpura-like bleeding in the face and the conjunctiva, dizziness, confusion and, in one case, transient visual problems. With increasing diameter and decreasing elasticity of the rope the deceleration with the head foremost leads to temporary engorgement of blood vessels entailed by capillary leaking. Nearly a century ago, Perthes reported similar symptoms of acute venous stasis in the head as a result of thoracic compression.

[Concept for the management of combined bone-soft tissue defects of the lower extremity]. / Versorgungskonzept kombinierter Knochen-Weichteil-Defekte an der unteren Extremität.

Severe crush injuries of lower limbs with loss of bone and soft-tissue need a clear concept of treatment. After resuscitation the examination and restitution of the injured limbs blood supply has absolute priority. Function of the tibialis posterior nerve plays an important role in the decision-making between amputation or reconstructive procedure. Long term healing is strongly influenced by the correct debridement. After stabilisation crushed soft-tissue and disintegrated bone fragments are removed. Second look operations are performed every 24-48 hours until a clean and good vascularized wound can be guaranteed. The coverage with a local or free muscle flap should be performed within 96 hours. The reconstruction of desteroid nerves is done secondary by nerve transplantation, except in case of primary replantation. Immediately after coverage of the soft-tissue defects the reconstruction of the bone defect is started. The method depends on the degree of bone loss and includes bone grafting, callus distraction or bone segment transports with unilateral fixators. The patients qualification for a reconstructive procedure has to be examined seriously.