Self-renewal system

M.-L. von Franz speaks of the Self as a self-renewing system in Redemption Motifs in Fairy Tales, Toronto, Inner City Books, 1980, p. 84. 

Central nervous system stem cells maintain an undifferentiated state and the capacity to self-renew in response to epidermal growth factor and fibroblast growth factor 507 Cell lineage studies reveal close associations between distinct neural cell types 508... 

Another way to keep microbial cells off surfaces is to create materials that constantly renew their surface, e.g., by being degraded. This so-called self-polishing does not keep microbes away effectively because the degradation process and the formation of a biofilm have different time scales. The latter takes merely hours, whereas the first should be in the range of days to months to provide a useful protection. In practice, such self-polishing systems only work in combination with released biocides and are discussed in Sect. 6.1 in greater detail. 

Schematic representation of the hematopoietic cascade in mice and human (hum). All the cells of the hematopoietic system are positive for antigen CD45. Based on this, the dynamics of surface antigen expression along development of different mature cells derived from the hematopoietic stem cell system can be observed. Rounded arrows indicate self-renewal potential. Smooth thinner arrows indicate directions of cellular differentiation. The identification of CDs (clusters definition) and other antigen cell markers are listed in the glossary. (LT-HSC - long term hematopoietic stem cell ST-HSC - short term hematopoietic stem cell MPP - multipotent progenitor CLP - common lymphoid precursor CMP - common myeloid precursor GMP - granulocyte-monocyte precursor MEP - megacaryocyte-erythrocyte precursor T - T lymphocyte B - B lymphocyte NK - natural killer cell DC - dendritic cell).

An alternative approach to broaden the availability of immunocompatible cells is to use stem cells that have the potential to differentiate into various cell types and also can be genetically manipulated because of their inherent self-renewal property. Thus, one could hope for the availability of functionally replaceable tissues off the shelf. Efficacy of using stem cells has been clinically proven beneficial in treating a variety of blood-related disorders. Furthermore, plasticity of stem cells has also been demonstrated in various animal models, suggesting that stem cells from one tissue type can be converted into cells of other tissues as well for example, when bone marrow cells were transplanted into liver-injured animals, these cells restored the liver by differentiating into liver cells. However, there is a need to engineer in vitro systems that can provide various microenvironments conducive to drive stem cells to defined cell types and then colonize them to generate needed tissue parts. 

The cellular elements of the immune system arise from pluripotent stem cells, a unique group of unspecialized cells that have self-renewal capacity. These cells are found in the blood islands of the embryonic yolk sac and in the liver of the... 

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