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Science
Friday > Archives
> 1998
> November
> November 6, 1998:
Hour Two: Cell Research Update / Kary Mullis
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For years, scientists have worked under the
assumption that neurons, the cells that make up the
networks in the brain and nervous system, aren't
replaced when they die. The theory went that
everyone was born with a certain number, which
decreased gradually throughout life. Cells lost due
to age, disease, or injury were gone. Period.
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But late last week, a report in the journal Nature
Medicine challenged that assumption. A group of researchers
at the Salk Institute for Biological Sciences in La Jolla,
CA discovered that neural cells in adult humans can
grow and reproduce. They injected chemicals known as
markers into five cancer patients, and found later that the
markers had been incorporated into the DNA of the patients'
brain tissues - which could only happen if the cells were
replicating. The finding, which surprised many in the
scientific community, may eventually have use in medicine.
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In another cell reproduction coup, a team of
scientists at the University of Wisconsin at
Madison report in the journal Science this week
that they have managed to culture undifferentiated
human embryonic stem cells. These cells, which are
the cells that exist in early embryos before cells
develop specific purposes, have the potential to
become any type of cell in the body.
The researchers have seen the cells develop
randomly into cartilage, bone, muscle, neural, and
gut cells. However, they can't yet control what the
cells become. Scientists have been trying to
culture stem cells for over a decade, hoping that
an inexhaustible supply of potential "anything
cells" could have profound implications for the
treatment of disease. While the team sees clinical
applications of the research as years away, the
finding has excited many disease researchers.
Brain cells and stem cells - we'll find out more on this segment
of Science Friday. And then...
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Different cells formed by the stem
cells:
(a) gut, (b) neural cells, (c) bone marrow,
(d) cartilage, (e)muscle, (f) kidney cells.
Image © Science
courtesy of U. Wisconsin-Madison
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He won the Nobel Prize in Chemistry in 1993 for developing a
technique called the polymerase chain reaction, which allows scientists
to quickly and easily duplicate chunks of DNA for study. But Kary
Mullis is also known for other things like surfing and his criticism
of the scientific establishment..
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The Polymerase Chain Reaction (PCR) is a technique that has revolutionized
genetics research. Instead of needing the vast quantities of genetic material
once needed to do an experiment, with PCR, a tiny sample is good enough.
Heat unzips and separates the double strands of the DNA molecule. Then
heat-resistant enzymes, collected originally from bacteria found in hot
spring vents, use free-floating nucleotides (the G, A,T,and C's of the
genetic code) to build the complement to each single strand. Then the
process repeats, multiplying one molecule into two, then four, then eight....
The process has made many genetic experiments that were once very laborious
and sensitive much easier to perform, and has allowed widespread use of
procedures like genetic testing and DNA fingerprinting.
On this segment of Science Friday, we'll talk to the famous - or infamous
- Kary Mullis about science and his place in it.
Guests:
Gerd Kemperman
Research Associate
Salk Institute for Biological Studies
La Jolla, CA
David Gottlieb
Professor, Anatomy and Neurobiology
Washington University School of Medicine
St. Louis, MO
Kary Mullis
1993 Nobel Laureate in Chemistry
Author, "Dancing
Naked in the Mind Field" (Pantheon)
San Diego, CA
Books/Articles Discussed:
"Neurogenisis in the adult human hippocampus," by P.S.
Eriksson, E. Perfilieva, T. Bjork-Eriksson, A. Alborn, C.
Nordborg, D. A. Peterson, and F. H. Gage. Nature Medicine,
November 1998.
"Embryonic stem cell lines derived from human
blastocysts," by J. A. THomson, M.A. Waknitz, J.J.
Swiergiel, V. S. Marshall, S.S. Shapiro, and J.M. Jones.
Science, November 6, 1998.
"Dancing
Naked in the Mind Field" by Kary Mullis. Pantheon Books, 1998.
Related Links:
Neuroscience
for Kids
American Academy of Neurology
The Visible Embryo
Cellbio.com
Embryo
Development Tutorial
1993 Nobel
Prize Announcement
This segment produced by:
Karin Vergoth
Web producer/Writer:
Charles Bergquist
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