| |
Stem cells can be obtained from the pluripotent stem cells of fetal tissue.
The fetal tissue comes from either fertilized embryos created for in vitro
use, but then not needed, or from terminated pregnancies. The researchers
who have studied stem cells from both sources are only allowed to do so,
according to Federal guidelines, only with the express and informed consent
of the couples involved.
Another potential source for stem cells is through a process called somatic
cell nuclear transfer. In this process, scientists remove the nucleus
(the part of the cell that contains its DNA in the form of genes and chromosomes)
from an unfertilized human egg cell. They then manipulate a human somatic
(body) cell so that its nucleus is incorporated unto the egg. This combination
cell appears to have the potential to develop into a human, and so it
is considered totipotent.
Stem cells have been used for a number of years in the treatment of cancers.
High dose chemotherapy will suppress or destroy the cancer patient's native
bone marrow. Transplants of donated bone marrow or umbilical cord blood
(both are now often referred to as stem cell transplants) are given to
provide the patient with blood stem cells to repopulate their bone marrow.
Among the cancers that have been successfully treated with stem cell transplants
are:
 Leukemia
Hodgkin's lymphoma
Non-Hodgkin's lymphoma
Multiple myeloma
Aplastic anemia
Breast cancer
Ovarian cancer
Testicular cancer
Sarcoma
Neuroblastoma
Brain tumors
|
 |
previous
chapter
