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Stem Cells

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Stem Cells Why the Controversy Over Stem cells? Embryonic Stem cells are derived from extra blastocysts that would otherwise be discarded following IVF. – PowerPoint PPT presentation

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Title: Stem Cells


1
Stem Cells
2
Importance of Stem Cell Research
3
Stem Cell History
1998 - Researchers first extract stem cells from
human embryos 1999 - First Successful human
transplant of insulin-making cells from
cadavers 2001 - President Bush restricts federal
funding for embryonic stem-cell research 2002 -
Juvenile Diabetes Research Foundation
International creates 20 million fund-raising
effort to support stem-cell research 2002 -
California ok stem cell research 2004 - Harvard
researchers grow stem cells from embryos using
private funding 2004 - Ballot measure for 3
Billion bond for stem cells
4
Stem Cell Definition
  • A cell that has the ability to continuously
    divide and differentiate (develop) into various
    other kind(s) of cells/tissues

5
Stem Cell Characteristics
  • Blank cells (unspecialized)
  • Capable of dividing and renewing themselves for
    long periods of time (proliferation and renewal)
  • Have the potential to give rise to specialized
    cell types (differentiation)

6
Kinds of Stem Cells
Stem cell type Description Examples
Totipotent Each cell can develop into a new individual Cells from early (1-3 days) embryos
Pluripotent Cells can form any (over 200) cell types Some cells of blastocyst (5 to 14 days)
Multipotent Cells differentiated, but can form a number of other tissues Fetal tissue, cord blood, and adult stem cells
7
Pluripotent
Multi- potent
Fully mature
8
Kinds of Stem Cells
  • Embryonic stem cells
  • five to six-day-old embryo
  • Tabula rasa
  • Embryonic germ cells
  • derived from the part of a human embryo or fetus
    that will ultimately produce eggs or sperm
    (gametes).
  • Adult stem cells
  • undifferentiated cells found among specialized or
    differentiated cells in a tissue or organ after
    birth
  • appear to have a more restricted ability to
    produce different cell types and to self-renew.

9
Pluripotent Stem Cells more potential to become
any type of cell
10
Multipotent stem cells
  • Multipotent stem cells limited in what the
    cells can become

11
Embryonic Stem Cells
Mainly from IVF
12
Sexual Reproduction
13
Stages of Embryogenesis
cleavage
8-cell stage
blastocyst
Blastocyst inner mass cells
14
Blastocyst Diagram
15
Adult Stem Cells
An undifferentiated cells found among specialized
or differentiated cells in a tissue or organ
after birth
  • Skin
  • Fat Cells
  • Bone marrow
  • Brain
  • Many other organs tissues

16
Induced Pluripotent Stem Cells
17
Bone Marrow
  • Found in spongy bone where blood cells form
  • Used to replace damaged or destroyed bone marrow
    with healthy bone marrow stem cells.
  • treat patients diagnosed with leukemia, aplastic
    anemia, and lymphomas
  • Need a greater histological immunocompatibility

18
Blood Cell Formation
19
Umbilical cord stem cells
  • Also Known as Whartons Jelly
  • Adult stem cells of infant origin
  • Less invasive than bone marrow
  • Greater compatibility
  • Less expensive

20
Umbilical cord stem cells
  • Three important functions
  • Plasticity Potential to change into other cell
    types like nerve cells
  • Homing To travel to the site of tissue damage
  • Engraftment To unite with other tissues

21
Stem Cell Applications
  • Tissue repair
  • - nerve, heart, muscle, organ, skin
  • Cancers
  • Autoimmune diseases
  • - diabetes, rheumatoid arthritis, MS

22
Tissue Repair
  • Regenerate spinal cord, heart tissue or any other
    major tissue in the body.

23
Replace Skin
http//www.youtube.com/watch?featureplayer_embedd
edveXO_ApjKPaI
24
Heart Disease
  • Adult bone marrow stem cells injected into the
    hearts are believed to improve cardiac function
    in victims of heart failure or heart attack

25
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26
Leukemia and Cancer
  • Studies show leukemia patients treated with stem
    cells emerge free of disease.
  • Injections of stem cells have also reduces
    pancreatic cancers in some patients.

Proliferation of white cells
27
Rheumatoid Arthritis
  • Adult Stem Cells may be helpful in jumpstarting
    repair of eroded cartilage.

28
Type I Diabetes
  • Pancreatic cells do not produce insulin
  • Embryonic Stems Cells might be trained to become
    pancreatic islets cells needed to secrete
    insulin.

29
Stem cells in the adult brain
30
new research reprogramming cells
31
Technical Challenges
  • Source - Cell lines may have mutations.
  • Delivery to target areas
  • Prevention of rejection
  • Suppressing tumors

32
Problems with Adult Stem Cells
Mutations can lead to leukemia
33
Why is Stem Cell Research So Important to All of
Us?
  • Stem cells can replace diseased or damaged cells
  • Stem cells allow us to study development and
    genetics
  • Stem cells can be used to test different
    substances (drugs and chemicals)

34
Why the Controversy Over Stem cells?
  • Embryonic Stem cells are derived from extra
    blastocysts that would otherwise be discarded
    following IVF.
  • Extracting stem cells destroys the developing
    blastocyst (embryo).
  • -Questions for Consideration-
  • Is an embryo a person?
  • Is it morally acceptable to use embryos for
    research?
  • When do we become human beings?

35
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