Regeneration under Pathological Conditions

Abstract

Most of the facts from which the principles governing regeneration of internal organs have been deduced have been obtained by the investigation of reparative processes after resection of an organ. Under natural conditions, however, injuries of the internal organs of the surgical type are rare. Lesions of a different type occur much more frequently, including those produced by heat, chemicals, radiation, and other agents, as well as tissue damage produced by pathogenic microorganisms and viruses. In all these cases the picture of regeneration is linked with the removal of the harmful action of the toxic agent and regression of the degenerative or dystrophic changes. The pathogenic factor, instead of being concentrated into one stage, as with resection of part of an organ, may extend over a considerable period of time, such as during prolonged administration of carbon tetrachloride or infection by pathogenic microorganisms. Moreover, whereas the injury produced by surgical trauma is local in character, heat or radiation may give rise to diffuse effects which extend throughout the organ. In that case the injury and, consequently, the reparative processes may involve only certain components of the organ.