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Thread: Dr. McDonald

  1. #131
    Senior Member Jeff's Avatar
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    Sergio, QuadPro - A less invasive procedure might also be more effective. If less of the cord is opened up and disrupted there might be a lot fewer immune cells penetrating the area and causing rejection. And less damage to the cord nd dura from the procedure is good, too. Opening a person up has a lot of risks... including infection. Developing the new delivery could be vital.


    ~See you at the SCIWire-used-to-be-paralyzed Reunion ~

  2. #132
    You make a good point Jeff. I just think that we would all be better off testing this first on Humans without this prolonged trial. If it shows any benefits, then start working on a different delivery method, which may or may not prove more effective. First we should get something going, then start tweaking it. It makes sense to me, but this is just my opinion.

  3. #133
    Sergio,
    You are forgetting...Dr. McDonald has already done a phase I human clinical trial here in the US. The differences...
    It was an invasive surgery and he used the stem cell sources of pigs.
    One of the things he realized with this trial was that invasive surgery is unnecessary. He explained to us that the spinal cord is constantly moving. Think about the damage that is done when you are opened up that way and cut on. Then think of a tiny needle...an over the skin injection...what a big difference it will make in the outcome of the transfer of stem cells.
    The other difference will be the cells that are transferred.
    The cells that are being transferred preferrably should be your own and should belong in the spinal cord.
    That's where somatic nuclear transfer comes in. As I understood, although somatic nuclear transfer has been done for a very long time, there are some very major differences in what Dr. McDonald will be doing, as compared to what has been done in the past... he will use an embryonic stem cell...not an egg. Dr. McDonald has done embryonic stem cell research for a very long time, and there are things he knows because of his results in the lab... he is also working together with others who are experienced with somatic nuclear transfer to quickly learn what is necessary but he will not move forward into human trials with this until he has proved in the lab that these cells are safe.
    I have no doubt that Dr. McDonald is moving forward as quickly as is humanly possible. There are salaries that have to be paid...so it's understandable that lack of funding could very possibly hold things up in that respect.

    [This message was edited by hope2findacure on 04-27-04 at 07:56 AM.]

  4. #134
    Banned Faye's Avatar
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    Originally posted by hope2findacure:

    Dr. McDonald will be doing, as compared to what has been done in the past... he will use an embryonic stem cell...not an egg.
    I am surprised! Do you know why? Is it because the embryonic stem cells are more readily available/can be stored, whereas egg cells cannot be stored and SCNT has to be carefully timed to the harvest of the egg cells?

    "Together we stand, divided we fall..."


  5. #135
    Faye,
    From what we understood, if an egg were used you could go on to clone a human...that's why somatic nuclear transfer is so controversial. But if a simple embryonic stem cell is used, the nucleus removed and then the individual's DNA put into it, you are creating a specific type of cells that have the individual's own DNA.

  6. #136
    hope2, I don't know what John McDonald is planning to do to create stem cells without using an egg but, based on what you describe, I can think of three possible approaches that Dr. McDonald.

    1. Somatic nuclear transfer to a stem cell. To do this, one would transfer the nucleus of a somatic cell into a stem cells, creating a stem cell with two nuclei and then kocking out the stem cell nucleus. It will be quite a task because of the small size of stem cells. To my knowledge, this has never been achieved.

    2. Fusing a stem cell and somatic cell. There is evidence that stem cells will fuse with somatic cells. If one fuses a stem cell with a somatic cell so that it would have two nuclei), one might be able to get a stem cell line that would express the genes of the somatic cell
    • if the stem cell nuclei were turned off or eliminated after the cells were fused
    • and if the somatic cell nucleus thinks that it is a stem cell and continues to behave like a stem cell.

    3. Transferring stem cell cytoplasm to a somatic cell. There is some evidence that it is possible to fool a nucleus into thinking that it might be another kind of cell. This was recently done by taking fibroblasts (skin cells) and incubating them in lymphocyte cytoplasm, after using chemicals to make the fibroblast membrane allow the lymphocyte cytoplasm to get into the fibroblasts. The cells started to behave like lymphocytes. It might be possible to do this and fool the somatic cells into becoming stem cells.

    Wise.

  7. #137
    Dr. Young,
    I apologize for my ignorance in this... Dr. McDonald was so very patient and explained all of this to us, but I'm just not able to understand everything that he told us. I'm not sure, but I think it sounded more like the 3rd process you described and you're right...what he's talking about doing, he told us had never been done before.
    Dr. McDonald's current research project along with his confidence and determination has given us hope that we've never had in the past.

  8. #138
    hope, yes, the third idea is fascinating but it has a strong theoretical basis. After all, somatic cell nuclear transfer to an egg is simply fooling the somatic cell nucleus into thinking that it is an egg nucleus and getting it to behave like the nucleus of an egg. There is very substantial evidence that cytoplasm "imprints" the DNA in the nucleus (i.e., turns some genes on and some genes off). When a nucleus is transferred into another cell, the cytoplasm may imprint upon that nucleus to behave differently.

    Please note, however, that if the Brownback bill (which they are still trying to pass in Congress) were to pass, it would criminalize all forms of somatic cell nuclear transfer, even to stem cells. On the other hand, the writers and supporters of the bill do not know enough about biology to think of the obverse procedure: egg cytoplasm transfer. Instead of bringing Moses (the nucleus) to the mountain (egg), bring the mountain (egg cytoplasm) to Moses (a somatic nucleus).

    It is a very ambitious task and I sincerely hope that Dr. McDonald achieves this.

    Wise.

  9. #139
    Dr. Young,
    We spoke with someone who is in frequent contact with Dr. McDonald and she did say that he will soon release an update concerning his research.
    Dr. McDonald is very aware and concerned about the political atmosphere here in the US. Everyone should be. Our government is continually attempting to ban this type of research, and you are right again, they are in ignorance about what they are trying to ban. They are extremely hypocritical in their reasoning, yet our hope for a somewhat normal existence could be extinguished if it depended 100 percent on what's done in this country. If people have to go to another country for help, then they will.
    I once wrote some letters to my Senators & Representatives, Governor Perry (and President Bush). I told them what happened to us and asked them to support stem cell research and Christopher Reeve's Bill. I talked about the invitro fertilzation clinics throwing away embryos that could instead be used to help people...it was a very long letter. I basically got the same response back from them all...we agree with George Bush's position regarding this issue and are against human cloning(although Kay Bailey Hutchison's didn't strike me as so negative and closed)...thank you for your letter, etc.
    Well, then I answered them and said I'm against human cloning also...
    It was as though they didn't read my letter, but read "stem cell" and equated it with human cloning. You know it just seemed like I was talking to a brick wall.

    [This message was edited by hope2findacure on 04-28-04 at 09:50 AM.]

  10. #140
    hope, you have pointed out a really important fact. Our current policy is not only due to President Bush. There is a general tendency to blame only George Bush but we should be aware that there is not sufficient support in Congress even to pass a bill that override President Bush's policy on embryonic stem cell funding of NIH. Note that they could easily attach it as an amendment to some bill that the administration really wants to pass, such as funding of the Iraqi war, so that he would be reluctant to veto. On the matter of SCNT, if my memory served me correctly, the House of Representatives passed their version of the Brownback bill criminalizing SCNT with a margin of 238 to 160 (or something like that). The only reason that the Brownback Bill did not pass was because several prominent Republican senators (Hatch and Spector) stopped it. Senator Feinstein's bill (to ban just reproductive cloning) never saw the light of day (got to a vote). President Bush would not have been able to do what he did if he did not have the support of Congress.

    Wise.

    P.S. I added the word "not" to the final sentence of the post.

    [This message was edited by Wise Young on 05-01-04 at 12:01 PM.]

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