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01/10/2007
Stem Cells and Stardust
Last Saturday, January 6, was a beautiful sunny day here in New
Jersey with the temperatures a record-setting 70-72 degrees
Fahrenheit for the date. Unfortunately, Saturday also marked the
third occasion last week that I attended a wake or memorial
service. One was for a former colleague at Bell Labs, William
Bonner, 65, crystal grower extraordinaire. Bill, while in high
school, entered a crystal-growing experiment in a Newark
science Fair and won first prize. At Bell Labs, despite not
having a Ph.D., he worked his way up growing crystals of
various materials, left Bell Labs to found his own company,
Crystallod, Inc., and also was president of the American
Association for Crystal Growth. If you’ve had laser eye surgery,
one of Bill’s crystals may have been used in the laser.
In last week’s column, I wrote about some of 2006’s top science
stories, focusing on the work of Wake Forest University
researchers. One of the topics was the collaborative work of
Anthony Atala, director of the Institute for Regenerative
Medicine at Wake, and colleagues on artificial bladders. This
week I’ve seen Atala interviewed on a number of TV news
programs and the work on stem cells by a Wake Forest-Harvard
team led by Atala was headlined in an article by Rick Weiss on
the front page of the January 8 Star-Ledger.
If this stem cell work holds up to its promise I wouldn’t be
surprised if it results in a Nobel Prize for Atala and/or other
researchers such as Dario Fauza of Children’s Hospital in
Boston. The stem cells have been isolated from amniotic fluid in
pregnant women and in placental afterbirth. Amniocentesis is a
standard procedure in which samples of amniotic fluid are taken
during pregnancy to detect potential birth defects. Atala and his
team, which includes workers at Children’s Hospital, have
injected amniotic stem cells in the diseased brains of mice and
grown new brain cells that make normal connections with other
healthy neurons. They’ve also used amniotic cells to grow bone,
muscle, fat, liver and blood vessel cells.
Fauza has been using amniotic cells to grow cartilage to repair
defective windpipes as well as to grow tendon tissue to repair
defective diaphragms in newborn sheep. Fauza is seeking
approval to take amniotic cells from expectant mothers carrying
babies with defects and use these cells to grow tissues that will
be available to repair the defects when the babies are born. Atala
suggests that if a hundred thousand samples of amniotic cells
were taken from a small fraction of the 4 million pregnant
women there would be enough stem cell lines with sufficient
genetic diversity to satisfy the needs of virtually anyone with a
defect or disease that proves treatable with such stem cell
therapy. Of course, the work on amniotic stem cells suggests the
possibility that embryonic stem cells may not be needed and the
raging controversy might be resolved.
Life is a fragile thing. Bill Bonner, Carol Marchand, 76, and
John Knight, 46, all died suddenly and unexpectedly. Recently,
a local TV news program featured a story about a fellow in our
area who was sitting in his living room watching TV when a car
came crashing through the wall and killed him! Much luckier
were the inhabitants of a house in the Freehold area of New
Jersey. It was about 4:30 PM on Tuesday last week when they
heard a noise of some sort. Its source wasn’t determined until a
son arrived home and found a chunk of something in the
bathroom. The object, about 31/2 inches long and about 2 inches
wide and weighing 13 ounces, had plunged through the roof and
into the bathroom where it bounced off the floor and embedded
itself in the sheetrock wall. Last Saturday’s Star-Ledger carried
an article by Maryann Spoto reporting that geologists from
Rutgers University and an independent metallurgist have looked
at the object and determined that it’s an iron meteorite.
We’ve all seen reports of meteorites making it through the
atmosphere without burning up. It’s estimated that about 20-50
rocks from space hit Earth every day. I was surprised to read
that this grayish brown chunk is the first documented visitor
from outer space to hit New Jersey since 1829! Rutgers scientist
Jeremy Delaney says that the chunk is from the asteroid belt out
there between Mars and Jupiter and had been wandering around
for 4 billion years before finally coming to rest in New Jersey.
Except for meteorites and rocks from the Apollo Moon missions,
researchers in labs here on Earth haven’t had any extraterrestrial
rocks to work with - until Stardust. Stardust was a mission
launched by NASA in 1999 designed to sneak up on a comet,
81P/Wild2, and bring back samples of the fuzzy halo, or coma,
of the comet. In January 2004 Stardust flew within less than 150
miles of the Wild comet’s nucleus and collected tiny particles or
grains from the comet’s coma. It sailed past the comet collecting
the particles in a specially engineered aerogel, a glassy foam so
light it has the density of air but sturdy enough to trap the
particles even though the Stardust spacecraft was sailing past the
comet at 3-4 miles per second! Some particles were collected
when they impacted on aluminum.
Stardust brought the particles of Wild2 back to Earth in January
of 2006 and last month’s December 15 issue of Science had a
special section devoted to the first analyses of these thousands of
miniscule “rocks”, most of which were less than a micron in size.
There were roughly 10 thousand particles in the 1-300 micron
range. (With my calipers, I just measured the thickness of a page
in Science at roughly 50 microns.) One of the seven papers in
Science had I would guess nearly 200 authors from exactly 100
institutions all over the world!
I can’t begin to discuss in detail the results of the host of
measurements mage on these tiny particles. (You may be saying,
“Thank goodness for that!”) They range from microscopic and
mineralogical observations to the detection and analysis of
organic compounds in the particles to the isotopic composition of
the elements found in the particles. The main reason for going to
a comet and collecting bits of it is that comets were formed in the
far reaches of our solar system billions of years ago and should
contain the original stuff out of which our planets were formed.
Surprisingly, virtually all the grains from Wild2 are crystalline
and certain minerals had to have been formed under very hot
conditions. That is, they were formed near the Sun as it was in
its early stages. Since the comet was formed in the far reaches of
the emerging solar system the conclusion is that there was
mixing of the “presolar” and solar stuff on an immense scale.
One grain in particular contains calcium- and aluminum-rich
inclusions that are found in meteorites and are thought to have
formed in the hot innermost regions of the solar nebula, well
inside the orbit of the planet Mercury.
The findings support predictions a few years ago by F. H. Shu
and colleagues and by D. Bockelee-Morvan and coworkers.
These scientists predicted that there could have been massive
launchings of particles of these calcium- and aluminum-rich
compounds out from the young Sun to the far reaches of the solar
system beyond Neptune. If I interpret the work correctly, it
sounds as though the particles were launched like ballistic
missiles out over the plane of the disk in which the planets now
rotate around the Sun.
While we’re on the subject of the solar system, could we have
committed the first murder of a living thing on another planet? I
found this possibility discussed in an article by Seth Borenstein
in the Star-Ledger. Washington State University professor Dirk
Schulze-Makuch suggests that we looked for the wrong kind of
life in our Mars Viking expeditions in which we added water to
Martian soil and also heated the soil to see what happened. Here
on Earth our living cells contain salt water, not an acceptable
combination on frigid Mars. Schulze-Makuch proposes that a
life form based on cells containing water and hydrogen peroxide
is more appropriate. A mixture of water and peroxide would stay
liquid at –68 degrees Fahrenheit and would not destroy the cells
on freezing. If such life exists on Mars, we would have drowned
it by adding water or killed it by heating it.
I apologize if this column is somewhat disjointed. I’d planned to
write only about meteorites and Stardust but couldn’t ignore
Atala’s important work and the passing of a fellow crystal
grower. And, as I’m posting this column, we’ve just had a
passing snow shower and a few flakes stuck to the ground, if
only for a few minutes. Could our heat wave be over?
Allen F. Bortrum
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