| Popis: |
Investigations in a variety of systems have shown that dissociated single cells will, under appropriate conditions, aggregate and, if maintained in culture, will morphologically differentiate to resemble the original organ or tissue (23, 33, 34). It can further be shown that in mixed aggregates of cells prepared from different organs (for example, neural retina and liver) there occurs cell segregation such that cells originally derived from the same organ attached to each other and separate from the cells derived from a different organ. The simplest explanation for this observation is that cells have a preferential or higher affinity for homologous cells, and if free to move within the aggregate, will rearrange so as to be adjacent to homologous rather than hetero-logous cells. This simple view is probably an oversimplification, because not only do cells migrate to be adjacent to homologous cells, but they also take up characteristic positions within the aggregate which cannot be explained simply by differential affinities (33). |
