Wandering histiocytes, foreign body giant cells, and inflammatory connective-tissue cells are stimulated by degradation products of dead matrix to grow in and repopulate the area of an implant of decalcified bone. Histiocytes are more numerous than any other cell form and may transfer collagenolytic activity to the substrate to cause dissolution of the matrix. The process is followed immediately by new bone formation by autoinduction in which both the inductor cells and the induced cells are derived from ingrowing cells of the host bed. The inductor cell is a descendant of a wandering histiocyte; the induced cell is a fixed histiocyte or perivascular young connective-tissue cell. Differentiation of the osteoprogenitor cell is elicited by local alterations in cell metabolic cycles that are as yet uncharacterized. New evidence in favor of the theory of induction can be gathered from the process of bone formation in the interior of an implant of acellular, devitalized, decalcified, bone matrix. Differing from previous demonstrations of induction systems, which produce scanty deposits and less than 30-percent positive results, decalcified bone yields new bone in an amount proportional to the volume of the implant; the percentage of positive experimental results is as high as over 90 percent. The results of some 70 experiments on approximately 300 animals are summarized below to introduce a hypothesis of postfetal osteogenesis by autoinduction.
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Wandering histiocytes, foreign body giant cells, and inflammatory connective-tissue cells are stimulated by degradation products of dead matrix to grow in and repopulate the area of an implant of decalcified bone. Histiocytes are more numerous than any other cell form and may transfer collagenolytic activity to the substrate to cause dissolution of the matrix. The process is followed immediately by new bone formation by autoinduction in which both the inductor cells and the induced cells are derived from ingrowing cells of the host bed. The inductor cell is a descendant of a wandering histiocyte; the induced cell is a fixed histiocyte or perivascular young connective-tissue cell. Differentiation of the osteoprogenitor cell is elicited by local alterations in cell metabolic cycles that are as yet uncharacterized. New evidence in favor of the theory of induction can be gathered from the process of bone formation in the interior of an implant of acellular, devitalized, decalcified, bone matrix. Differing from previous demonstrations of induction systems, which produce scanty deposits and less than 30-percent positive results, decalcified bone yields new bone in an amount proportional to the volume of the implant; the percentage of positive experimental results is as high as over 90 percent. The results of some 70 experiments on approximately 300 animals are summarized below to introduce a hypothesis of postfetal osteogenesis by autoinduction.
Copyright remains with the authors and publisher.