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Stem Cells

Stem Cells. The Stem Cell Concept. A stem cell is an undifferentiated, dividing cell that gives rise to a daughter cell like itself and a daughter cell that becomes a specialized cell type. . What Is a Stem Cell?. Unspecialized cells Give rise to more than 225 specialized cells in the body

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Stem Cells

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  1. Stem Cells

  2. The Stem Cell Concept A stem cell is an undifferentiated, dividing cell that gives rise to a daughter cell like itself and a daughter cell that becomes a specialized cell type.

  3. What Is a Stem Cell? • Unspecialized cells • Give rise to more than 225 specialized cells in the body • Serve as the body’s repair system • Renew itself • Replenish other cells

  4. In Summary: Two Major Types of SC

  5. What Are the Sources of Mature Stem Cells? Mature Body Tissues

  6. Stem Cells are Found in the Adult, but the Most Promising Types of Stem Cells for Therapy are Embryonic Stem Cells

  7. Where Are Early Stem Cells Found? Who did it first? • In 1998, U. Wisconsin research team isolates stem cells from IVF-blastocysts 5 days of development

  8. The Inner Cell Mass is the Source of Embryonic Stem Cells The embryo is destroyed by separating it into individual cells for the collection of ICM cells.

  9. How Big Is a Blastocyst?

  10. Early stem cells are pluripotent Retain the special ability to develop into nearly any cell type teratoma What Are the Characteristics?

  11. Teratoma

  12. Cultured mouse embryonic stem cells. Additional Potential Dilemmas – Therapeutic Cloning to Obtain Matched Embryonic Stem Cells Cells from any source other than you or an identical twin present the problem of rejection. If so, how can matched embryonic stem cells be obtained? A cloned embryo of a person can be made, and embryonic stem cells harvested from these clones.

  13. Some Thorny Ethical Questions Are these masses of cells a human? Is it ethical to harvest embryonic stem cells from the “extra” embryos created during in vitro fertilization?

  14. Somatic Cell Nuclear Transfer (SCNT) Sometimes referred to as “therapeutic cloning”

  15. SCNT: Asexual Reproduction • No sperm involved • Transfers nucleus from a mature cell into a donor egg • Requires electric or chemical stimulus to begin dividing • Functionally different from regular fertilized egg

  16. What Should You Know About SCNT? • Purpose: • Find cures and therapies for diseases • Awaken the natural capacity for self-repair that resides in our genes • Potential Results: • Patients will receive own stem cells to treat disease • No need for donor match • Like transplantation, but without rejection

  17. How Would SCNT Treat Disease?

  18. What Should You Know About SCNT? • No reputable scientist wants to clone human beings • SCNT stem cells are alive in a Petri dish • Unless implanted in uterus, you can not generate a fetus • Evidence suggests that SCNT stem cells may never develop into a human even when implanted

  19. The Biotechnology of Reproductive Cloning Even under the best of circumstances, the current technology of cloning is very inefficient. Cloning provides the most direct demonstration that all cells of an individual share a common genetic blueprint.

  20. Therapeutic Cloning Is there any ethical difference between therapeutic and reproductive cloning?

  21. The Next Step? Highly unlikely. Attempts at human cloning are viewed very unfavorably in the scientific community.

  22. http://learn.genetics.utah.edu/units/cloning/clickandclone/

  23. Both Kinds of SCR are Needed

  24. What Are the Current State Restrictions?

  25. Which States Currently Support ESCR?

  26. http://www.pbs.org/wgbh/nova/sciencenow/3209/04.html

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