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i wrote this article in 2005. the information about stem cells - what they are - is still valid, although the research data is out of date . i hope it will clarify some of the questions people on this list have been asking. again, i remind you that this is my understanding of the facts and i have tried not to take sides. hilary blue. p.s. please note 'chromosomes' and 'genetic material' equals DNAHilary Blue wrote: > > >>> >>> What is all the fuss about? >>> >>> There has been much said and written about stem cells in the media, >>> on Capitol Hill, and in living rooms across the country. Yet it >>> seems to me that there is much ignorance and even misinformation >>> being bandied about, sometimes even being touted as gospel truth. >>> Here is my attempt to make sense out of the issue. >>> >>> To understand stem cells we must first consider where they come >>> from. Every cell in the human body contains a nucleus which holds >>> the genetic material, the chromosomes. In regular tissue (somatic >>> cells) these chromosomes are double (diploid). The reproductive >>> cells (eggs and sperm) have only single chromosomes (haploid). Thus >>> when a sperm and an egg cell unite in the act of fertilization, the >>> fertilized egg will have double chromosomes with one strand from >>> the mother and the other from the father. This fertilized egg cell >>> divides into two and then four, eight, 16, 32, 64..... And >>> this little group of cells is undifferentiated. Each has the >>> potential to develop into any part of the human body, i.e. it is >>> pluripotent. >>> >>> At about this point, the clump of cells forms a hollow ball, known >>> as the blastosphere, and it is possible to map out exactly which >>> cells are going to develop into which tissues. As each organ and >>> tissue develops in the embryo, and even after birth and into adult >>> life, some of the cells remain undifferentiated. These are the >>> so-called adult stem cells. They retain the ability to develop into >>> regular tissue cells, but are not as potent as the embryonic cells. >>> It seems that, for example, stem cells from the marrow will develop >>> into blood cells but not into brain cells or pancreas cells.So, >>> although they offer some promise, they are not as versatile as >>> embryonic stem cells. >>> >>> The umbilical cord also contains stem cells, and this seems a very >>> promising area for research, especially when the cord is saved for >>> the future use of the baby. Should a patient need stem cell >>> treatment for some future disease; he would have a store of his own >>> completely compatible cells to call upon. >>> >>> The most successful but most controversial form of stem cell >>> production is Somatic Cell Nuclear Transfer (SCNT). A cell is taken >>> from the undifferentiated blastosphere. Its nucleus is removed and >>> replaced with the nucleus from a somatic cell. This can then be >>> cultured to form a line of stem cells. Unfortunateely, all stem cell >>> lines weaken over time and thus become less useful, so new lines >>> need constantly to be developed. Until now this has been the most >>> promising source of stem cells for research. The original cell is >>> taken from a very early stage of embryonic development, the >>> blastophere, which can develop into any of the numerous cell types >>> in the body. >>> >>> It must be noted that the source of these embryos is from >>> fertilization clinics, where many embryos are discarded and >>> incinerated after they are no longer needed by the clients. This >>> destruction of unwanted embryos is accepted and performed on a >>> regular basis when a couple has used as many embryos as they want. >>> Or they can donate the unwanted embryos to research. >> >> >> >>> And therein lies the controversy. >>> >>> For there are those that say that using an embryo that has the >>> potential for life is destroying that life. And that leads to the >>> question: when does life begin?. There are those who say it begins >>> at birth, and those who say it begins at conception, and every stage >>> in between. Some say it is the earlieet age at which a fetus will >>> survive after a premature birth, which is about six months. This is >>> consistent with Muslim belief and has resulted in Saudi Arabia >>> setting up a stem cell research institute which is attracting >>> scientists from countries where science is generally regarded as >>> being more advanced. >> >> >> >>> But the viewpoint taken by most stem cell research scientists is >>> that the stage at which the embryo begins to differentiate into >>> distinct organs and other body parts is the point at which sentient >>> life begins.A formless cluster of multipurpose cells becomes a >>> planned structure, with each part destined for a future definite >>> purpose. Until that point, any embryonic cell could potentially >>> develop into a human being; that is essentially what happens in >>> multiple births. Identical twins are formed from the two cells >>> created after the first division of the egg cell. This stage, when >>> the cells become dedicated to their future role, become presumptive >>> bone or liver or nerve cells or whatever, occurs on about the 14th >>> day after conception. >> >> >> >> But in the meantime, during the past several weeks, a researcher in >> South Korea, Woo Suk Hwang, has announced the development of a more >> sophisticated version of SCNT. He uses a donated egg cell and >> replaces its haploid nucleus with a diploid nucleus from one of the >> patient's own somatic cells. From this he derives stem cells that are >> completely genetically compatible with the patient and these stem >> cells develop into whatever tissue the patient needs. There is no >> fertilization, and no embryo. There is no destruction of life. And >> even if you argue that an egg cell is the fore-runner of a living >> being, women have been destroying and casting off egg cells on a >> monthly basis since the days of Adam and Eve. >> >> This brief overview is completely my own point of view and in no way >> reflects the policies or views of the PFNCA or any board members, >> employees or members thereof. The information contained herein is >> based on my understanding and interpretation of data garnered from >> conferences, symposiums and PAN forums I have attended over the past >> few years, and from the PIEN Listserv. >> >>> >>> >>> hilary blue >>> >> >> >> > > > ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn