>From The Boston Globe,
Scientists grow frog eyes and ears, technology that could be used to grow
By Eric Prideaux, Associated Press, 1/3/2000 13:16
TOKYO (AP) Japanese researchers have grown frog eyes and ears in a lab using
the animal's own embryo cells, technology a scientist said Monday could
eventually help doctors replace lost or damaged human sensory organs using
cells from the patients' bodies.
Makoto Asashima, a biologist at prestigious Tokyo University, said the
process is an alternative to donor transplants.
The team cultivated thousands of embryo cells in a retinoic acid solution
for five days to produce the organs, he said.
Varying the concentration of the retinoic acid somehow brings forth
different genetic instructions in the cells, Asashima said. A lower
concentration activates a set of genes producing eyes, while a higher
concentration activates genes producing ears.
The researchers used embryonic stem cells, the ancestral cells that develop
into the tissues and organs in the body.
The procedure is different from cloning, in which a single cell from an
organism grows into a copy of the original, he said.
Asashima said his team is the first to produce the eyes or ears of an animal
in a test tube.
In a similar, simpler procedure, the researcher said he previously grew frog
kidneys and transplanted them into other frogs.
The recipient animals lived for more than a month, he said. The team did not
test the survival rate of frogs with transplanted natural kidneys, he said.
Hideyuki Okano, a professor of neural development at Osaka University's
Graduate School of Medicine, said Asashima's work was ''extremely
Okano, who has been following the research, said it could eventually help
scientists reduce reliance on donors for rare organs.
Scientists are already able to grow human skin from patients' own cells, and
such transplants are carried out in the United States, Europe and Japan,
Asashima said he plans to submit his findings, which were first reported in
Monday's Mainichi newspaper, to one of two Japanese scientific journals,
Zoological Science or Developmental Growth and Differentiation.
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