Vitality and time course of wounds.

The term "wound" describes the morphologic-functional disruption of the continuity of a tissue structure. A wound can be inflicted during life--when the cardiovascular and respiratory system is still intact--or after death, i.e. after cardiac and respiratory arrest. Traumatization during life triggers vital reactions that do not occur in postmortem wounds. Three types of vital reactions in wound healing can be distinguished: Reactions of the scavenger type, which are almost exclusively mediated by blood cells. Reactions by complex signal transduction pathways, which involves cascade-like release of chemokines, cytokines and adhesion molecules and may influence type 1 and type 3 reactions. Reactions of the scarring type, which involve the final repair of the damaged tissue and are carried out primarily by cells residing at the wound edges, i.e. partly concerning mesenchymal cells and partly tissue-specific cells dependent on the involved organ system. The three different types of reaction follow roughly parallel temporal courses that include cascade-like interactions among themselves. Whereas demonstration of a vital reaction suffices to differentiate an intravital wound from a postmortem wound, the vital reactions themselves follow strictly temporal courses. The regular time-dependent occurrence of each phenomenon allows--in limits--a reliable temporal classification of wound healing. A review will be given especially demonstrating the actual German scientific research in vitality and in skin wound timing as well as in timing of mechanical injury of the brain.