tailieunhanh - Chapter 066. Stem Cell Biology (Part 1)

Harrison's Internal Medicine Chapter 66. Stem Cell Biology Stem Cell Biology: Introduction Stem cell biology is a relatively new field that explores the characteristics and possible clinical applications of the different types of pluripotential cells that serve as the progenitors of more differentiated cell types. In addition to potential therapeutic applications (Chap. 67), patient-derived stem cells can also provide disease models and a means to test drug effectiveness. Identification, Isolation, and Derivation of Stem Cells Resident Stem Cells The definition of stem cells remains elusive. Stem cells were originally postulated as unspecified or undifferentiated cells that provide a source of renewal of skin, intestine,. | Chapter 066. Stem Cell Biology Part 1 Harrison s Internal Medicine Chapter 66. Stem Cell Biology Stem Cell Biology Introduction Stem cell biology is a relatively new field that explores the characteristics and possible clinical applications of the different types of pluripotential cells that serve as the progenitors of more differentiated cell types. In addition to potential therapeutic applications Chap. 67 patient-derived stem cells can also provide disease models and a means to test drug effectiveness. Identification Isolation and Derivation of Stem Cells Resident Stem Cells The definition of stem cells remains elusive. Stem cells were originally postulated as unspecified or undifferentiated cells that provide a source of renewal of skin intestine and blood cells throughout the lifespan. These resident stem cells are now identified in a variety of organs . epithelia of the skin and digestive system bone marrow blood vessels brain skeletal muscle liver testis and pancreas based on their specific locations morphology and biochemical markers. Isolated Stem Cells Unequivocal identification of stem cells requires the separation and purification of cells usually based on a combination of specific cell-surface markers. These isolated stem cells . hematopoietic stem HS cells can be studied in detail and used in clinical applications such as bone marrow transplantation Chap. 68 . However the lack of specific cell-surface markers for other types of stem cells has made it difficult to isolate them in large quantities. This challenge has been partially addressed in animal models by genetically marking different cell types with green fluorescence protein driven by cell-specific promoters. Alternatively putative stem cells have been isolated from a variety of tissues as side population SP cells using fluorescence-activated cell sorting after staining with Hoechst 33342 dye. However the SP phenotype should be used with caution as it may not be function for stem cells. .