Biomedical Engineering Reference
In-Depth Information
team derived seems to form bone, muscle, and immature
brain cells, for example. The South Korean scientists
suspect that their method of removing the egg's nucleus
might have been one of the secrets of their success. In-
stead of sucking the nucleus out with a pipette, which in
past work seemed to damage the protein machinery that
controls cell division, the team nicked a small hole in the
egg's membrane and gently squeezed out the genetic
material. Perhaps the Korean scientists' most important
advantage was the whopping 242 eggs they had to work
with. The team obtained oocytes and donor cells from 16
healthy women, who underwent hormone treatment to
stimulate their ovaries to overproduce maturing eggs.
The women who donated specifically for the experi-
ments were not compensated, and were informed that
they would not personally benefit from the research.
In this study the adult cell (donor cell) and the egg
(oocyte) came from the same person. This made difficult
to prove that the embryo really was cloned. The process
was also very inefficient, taking 242 eggs to create just
one ES cell line. However, in 2005 the Hwang's team
created 11 more ES cell lines from cloned embryos in an
impressive study that answers all the criticisms of their
original study. They have also greatly increased the effi-
ciency of the process: the 11 lines came from just 185
fresh eggs donated by 18 unpaid volunteers, meaning an
average of only 17 eggs was needed per ES cell line
[41]
.
The donor ''adult'' cells came from patients aged 2-56,
with a variety of conditions ranging from spinal injuries to
an inherited immune condition. The work proves that
matching ES cells can be derived via therapeutic cloning
from donors of any age and sex.
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