Stem cell research

[Jim Slattery <jamesslattery1@xxxxxxxxxxx>]

The following is not to be taken as medical fact, but is only the personal 
opinion of the writer, 

Dr James F Slattery, PhD Soc Sc

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STEM CELL and CLONING RESEARCH

Much of the dispute about stem cells and cloning arises from a misunderstanding 
of the terms used, between their specific and unique meaning to scientists, and 
their common meaning to the general public.

EMBRYONIC STEM CELLS

Take, for instance, the word "embryo". The scientist defines the term as a 
human organism from the first cell cleavage to 8 weeks. However, in the view of 
most non-scientific-minded people, "embryo" is synonymous with "foetus", and 
therefore presents as a tiny, developing human being.

However, the organism from which stem cells are derived for research is 
typically four or five days old. It comes from eggs that have been fertilized 
"in vitro", i.e., in a glass dish usually at a fertilisation clinic. They are 
NOT derived from eggs that have been fertilized in a woman's body. 

At this stage, the organism is called a blastocyst. The embryonic stem cells 
are isolated by transferring the inner cell mass of the blastocyst into a 
culture medium in a dish. The cells can then be cloned (replicated) many times. 
However, this process is somewhat inefficient, as stem cell lines are not 
produced each time that cells are extracted and transferred to a culture dish.

If a person has a view that "life" begins at conception (as soon as the sperm 
enters the ovum) and that doing anything the fertilized ovum is wrong, other 
than implanting it in a womb in order to produce a human child, then nothing 
one can say to the contrary will change their mind. Any attempt to remove 
cellular material from such an organism, even though the material is going to 
be replicated, and not implanted in a womb, would be considered as "abortion" 
by such a person, and the disposal of the unwanted tissue from the blastocyst 
would be classed as "murder".

However, if people have a mistaken view about the methodology of extracting 
"embryonic" stem cells, and have the facts lain before them, that ESCs are 
produced from an ovum, from the tiny mass of the blastocyst, and NOT from an 
already developing foetus, then we may have a chance at convincing them of the 
value and ethicality of ESC research.

ADULT STEM CELLS

Adult stem cells are undifferentiated cells, found throughout the body after 
embryonic development, that multiply by cell division to replenish dying cells 
and regenerate damaged tissues. Also known as somatic stem cells (meaning "of 
the body"), they can be found in juveniles as well as in adults. The term 
"adult" as used here implies post-foetal.

Scientific interest in adult stem cells centres on their ability to divide 
(self-renew) indefinitely, and to generate all the cell types of the bodily 
organ from which they originated, potentially regenerating the entire organ 
from a few cells; thus, they are more properly called "progenitor cells". 
Unlike embryonic stem cells, the use of adult stem cells in research and 
therapy is not considered to be controversial, as they are derived from adult 
donor tissue samples rather than embryonic tissue. Progenitor cells have the 
capacity to differentiate into a specific type of cell.

In contrast to stem cells, however, they are already far more specific, and can 
be "pushed" to differentiate into their "target" cell. The most important 
difference between embryonic stem cells and progenitor cells is that stem cells 
can replicate indefinitely, whereas progenitor cells can only divide a limited 
number of times. Using adult stem cells is considered by the non-scientific 
community to be more "ethical" than using ESCs.



THERAPEUTIC CLONING

In genetics and developmental biology, SCNT (somatic cell nuclear transfer) is 
a laboratory technique for creating a cloned embryo, using an ovum (female 
egg). The process can be used in embryonic stem cell research, or potentially, 
in regenerative medicine where it is referred to as "therapeutic cloning".

In SCNT, the nucleus of a somatic cell (a body cell other than a sperm or egg 
cell) containing that organism's DNA, is removed and saved, and the remainder 
of the cell is discarded. At the same time, the nucleus of an ovum (egg cell) 
is removed from the ovum, to be replaced by the nucleus of the somatic cell. 
After being inserted into the egg, the somatic cell nucleus is "reprogrammed" 
by the host cell. The ovum, now containing the nucleus of a somatic cell, is 
stimulated with a shock, and begins to divide. After many mitotic divisions 
(cell division in which the nucleus divides into nuclei containing the same 
number of chromosomes) in a culture dish, this single ovum forms a blastocyst 
(an early stage embryo with about 100 cells), with almost identical DNA to the 
original somatic cell. The aim of carrying out this procedure, rather than the 
embryonic stem cell method, is to obtain stem cells that are genetically 
matched to the donor somatic cell.  

Some people still call this process "abortion", although no embryo is formed 
and destroyed. They consider the "enucleated" ovum obtained in the therapeutic 
cloning to be the equivalent of the ovum in the embryonic method, although the 
enucleated ovum is not capable of being planted in a womb. They refer to the 
material discarded from the ovum as "murder". This despite the fact that 
millions of women throughout the world "destroy" at least one complete ovum 
every month, in the process of menstruation.

My personal opinion is in favour of adult stem cell therapy, and I hope I live 
long enough to benefit from it.

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