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Zusammenfassung: Zwischen Oktober 1987 und August 1988 wurden 15 Malleolarfrakturen (13mal Typ B, zwei isolierte Innenknchelfrakturen) und sechs Flakefrakturen (viermal Femurrolle, zweimal Talus) mit resorbierbaren Stiften (Biofix) bungsstabil operativ versorgt und prospektiv dokumentiert. Es handelt sich um Polyglykolsurefibrillen die mit einer Schmelztechnik zusammengepret und mit Polydioxanon ummantelt sind, ihre Scherfestigkeit nimmt in zirka vier Wochen um die Hlfte ab. Sie sind in verschiedenen Lngen und Strken erhltlich. Die Frakturen wurden mit einer Zuggurtungsosteosynthese unter Verwendung von PGS-Stiften und PDS-Kordel oder Maxon-Fden (Strke 1) stabilisiert, die Abscherfragmente mit zwei bis drei Stiften aus PGS fixiert. Die Nachbehandlung erfolgte funktionell. Die Frakturen waren nach sechs Wochen bei zwlf Patienten verheilt, nach sieben Wochen bei zwei und lediglich bei einem Patienten erst nach neun Wochen. Die kncherne Ausheilung der Flakefrakturen dauerte lnger, nach sechs Wochen waren erst eine, nach sieben Wochen zwei und nach neun Wochen drei Frakturen fest. Vollbelastung war bei den Malleolarfrakturen durchschnittlich nach 8,9 Wochen, bei den Flakefrakturen nach 10,8 Wochen erreicht. Die Dauer der Behandlung betrug 10,2 Wochen beziehungsweise 12,4 Wochen. Unseres Erachtens wurde mit dieser Studie der Nachweis erbracht, da Auenknchelosteosynthesen mit resorbierbarem Material unter funktioneller Nachbehandlung mglich sind. Die Stifte eignen sich des weiteren aufgrund ihrer hohen Scherfestigkeit ideal zur Refixation von Flakefrakturen.

The binding and assembly of the coagulation proteases on the endothelial cell surface are important steps not only in the generation of thrombin and thrombogenesis, but also in vascular cell signaling. Effector cell protease receptor (EPR-1) was identified as a novel leukocyte cell surface receptor recognizing the coagulation serine protease Factor Xa but not the precursor Factor X. We now demonstrate that EPR-1 is expressed on vascular endothelial cells and smooth muscle cells. Northern blots of endothelial and smooth muscle cells demonstrated three abundant mRNA bands of 3.0, 1.8, and 1.3 kDa. 125I-Labeled Factor Xa bound to endothelial cells in a dose-dependent saturable manner, and the binding was inhibited by antibody to EPR-1. No specific binding was observed with a recombinant mutant Factor X in which the activation site was substituted by Arg196 --> Gln to prevent the proteolytic conversion to Xa. EPR-1 was identified immunohistochemically on microvascular endothelial and smooth muscle cells. Functionally, exposure of smooth muscle cells or endothelial cells to Factor Xa induced a 3-fold and a 2-fold increase in [3H]thymidine uptake, respectively. However, receptor occupancy alone is insufficient for mitogenic signaling because the active site of the enzyme is required for mitogenesis. Thus, EPR-1 represents a site of specific protease-receptor complex assembly, which during local initiation of the coagulation cascade could mediate cellular signaling and responses of the vessel wall.

Tissue factor (TF) is an integral membrane glycoprotein which, as the receptor and essential cofactor for coagulation factors VII and VIIa (FVII and FVIIa, respectively), is the primary cellular activator of the coagulation protease cascade. Previous studies on the procoagulant activity of a variety of cell types (either lysed or in the intact state) have variously been interpreted as showing that TF is either stored intracellularly or is present in a cryptic form in the surface membrane. Using mAbs to TF, we have directly investigated the subcellular localization and functional activity of TF in lipopolysaccharide-stimulated blood monocytes and J82 bladder carcinoma cells. Blocking of surface TF of viable cells with inhibitory anti-TF mAbs abolished greater than 90% of TF activity of the intact cells as well as of lysed cells. Furthermore, quantitative analysis of the binding of FVII and anti-TF mAb to J82 cells demonstrated that all surface-expressed TF molecules were capable of binding the ligand, FVII. By immunoelectron microscopy, TF was present only in the surface membrane of monocytes and J82 cells, although the latter also contained apparently inactive TF antigen in multivesicular bodies. On the intact cell surface the catalytic activity of the TF-FVIIa complex was investigated and found to be markedly less relative to cell lysates. Membrane alterations that affect the cofactor activity of TF may be a means of regulating the extent of initiation of the coagulation protease cascade in various cellular settings.