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Thread: Study of the effects of "chronic scar" on axonal growth in spinal cord injury

  1. #11
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    Wise. Wouldn’t neurosurgery to the cord result in a fibroblast invasion as well when the surgeon’s knife cut trough the dura and so on into the cord itselfe? Right?

  2. #12
    The way I dumb this down (as DA would say) for my thinking process is using something I have seen.

    You have a serious bruise on your skin and it heals and leaves no scar. You have a tiny cut and after it heals you have a scar.

    Doesn't mean though that when you were bruised you didn't injure alot of surrounding tissue..you most certainly did..but you didn't disconnect the skin thus it doesn't have to form scar tissue to reconnect the two ends of the skin.

    Just my simply minded way of trying to understand.
    Life isn't about getting thru the storm but learning to dance in the rain.

  3. #13
    Quote Originally Posted by Wise Young
    Cripply, if you use a knife and cut the spinal cord, there is fibroblast invasion and a fibrous scar does occur. However, if you contuse the spinal cord, only glial proliferation occurs at the edges of the lesion site. Penetrating wounds of the spinal cord can cause fibrous scars. Contusions do not. Most people have contusions.

    Wise.
    My concern is that there might be differences between animals and humans in this regard. The paper does not say that the scar pictured is from a cut cord.

  4. #14
    Quote Originally Posted by Leif
    Wise. Wouldn’t neurosurgery to the cord result in a fibroblast invasion as well when the surgeon’s knife cut trough the dura and so on into the cord itselfe? Right?
    This is true. It is the reason many doctors are reluctant to cut into the spinal cord unless they have to (like in the case of a spinal cord tumor). It is one of the reasons why I have been uncomfortable with the surgery being carried out in Portugal where they cut out a part of the spinal cord that supposedly has the "scar". Several animal studies have suggested that if the dura is carefully closed after the injury and prevented from adhering to the spinal cord, fibroblast invasion in to the injury site is limited. In the ChinaSCINet, we are planning to introduce the cells through a small puncture as opposed to cutting into spinal cord.

    I have now studied contused spinal cords of animals for over 20 years. In general, contused spinal cords do not show thick deposits of collagen inside the spinal cord at the injury site. Collagen is made by fibroblasts. While there may be some collagen deposits on the surface of contused spinal cord, especially where there is adhesion between the spinal cord and arachnoid, these are usually limited to the surface. By the way, the spinal cord contain extracellular matrix molecules that prevent migration of cells that the spinal cord considers to be "peripheral". For example, generally fibroblasts and Schwann cells (which the spinal cord treats as peripheral cells) injected into the spinal cord will not migrate far from the injection site into the surrounding cord.

    For many years, the Schwab group in Switzerland used the so-called "over-hemisection" model to examine regeneration. However, a number of years ago, they adopted our contusion model. I found the Tuzynski paper particularly interesting because they cut into the spinal cord and find that the resultant "scar" does not seem to impede axonal growth in the cervical spinal cord.

    Wise.

  5. #15
    I wonder if other scientists, or researchers, pay as much attention to your research
    as you do to with theirs?

  6. #16
    Quote Originally Posted by kz
    dr. young,
    hi, how about gunshot wound that caused "complete" asia A paralyis,when the bullet hit the bone and did not even hit the spinal cord (soft tissue) ? what is the main reason of "complete" asia paralysis when the bullet hit the spine (bone) and it did not even hit the soft tissue ? what kind of scar exist in this kind of situation ?what is the main reason of "complete" asia A paralysis in this kind of situation (this is my situation)? what is causing the disruption of spinal cord in this kind of situation ? is this kind of injury harder to cure or easier compare to contusion ,or it does not matter at all when it comes to any kind of treatment (cure) ? please explain this kind of injury a little more.
    thanks so much
    Tissue and cell parts are elastic. If you stretched them slowly, they can stretch quite a lot perhaps 2-3x. However, if you stretch them too far or too fast, they break. Axons are a lot like rubber bands. The critical breaking velocity for them is about 0.5 meters/second.

    A contusion of the spinal cord with a weight that is dropped from 12.5-75.0 mm height compresses the spinal cord at the rate of 0.4-1.2 meters/sec. Because the spinal cord is really like a tube of jello, the only directions that the spinal cord can go when it is compressed is longitudinal.

    Paradoxically, myelinated axons are the first and most sensitive to stretch. The reason is that most of the axon is covered with myelin except for areas between the myelin, called nodes of Ranvier. Since the parts of axons that are covered with myelin do not stretch as much, all the stretch is concentrated on the nodes of Ranvier.

    The gray matter of the spinal cord, however, is damaged due to shearing forces that occur with the spinal cord is indented. Also, the shearing forces can damage blood vessels that cause bleeding into the spinal cord. Blood is toxic to the tissue and contributes to the damage.

    Now, a bullet can damage the spinal cord without penetrating into the spinal cord. In addition to possibly causing bone to indent the spinal cord, a bullet can also produce a shock wave that transmits through the spinal cord. The damage produced by the bullet depends on the velocity of the shock wave.

    While such "shock" waves have long been blamed for gunshot wounds, please note that many studies have suggested that these shock waves have been overestimated. Due to public protest, the U.S. government has stopped experiments involving gunshot wounds of the spinal cord in animals. However, studies carried out in China suggest that the bullet can pass close to the spinal column but will not damage the spinal cord unless the bullet contacts the spinal column bone.

    Wise.

  7. #17
    Quote Originally Posted by Buck_Nastier
    I wonder if other scientists, or researchers, pay as much attention to your research
    as you do to with theirs?
    I don't know. Lots of people don't listen to me, including many on this site.

    Wise.

  8. #18
    Quote Originally Posted by Wise Young
    I don't know. Lots of people don't listen to me, including many on this site.

    Wise.
    I didn't mean anything negative by my post, i'm just impressed with
    how much you know about everyone elses research. It's great that
    we are able to get all this info at one site. Thanks.

  9. #19
    Senior Member
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    Quote Originally Posted by Wise Young
    This is true. It is the reason many doctors are reluctant to cut into the spinal cord unless they have to (like in the case of a spinal cord tumor). It is one of the reasons why I have been uncomfortable with the surgery being carried out in Portugal where they cut out a part of the spinal cord that supposedly has the "scar". Several animal studies have suggested that if the dura is carefully closed after the injury and prevented from adhering to the spinal cord, fibroblast invasion in to the injury site is limited. In the ChinaSCINet, we are planning to introduce the cells through a small puncture as opposed to cutting into spinal cord.

    I have now studied contused spinal cords of animals for over 20 years. In general, contused spinal cords do not show thick deposits of collagen inside the spinal cord at the injury site. Collagen is made by fibroblasts. While there may be some collagen deposits on the surface of contused spinal cord, especially where there is adhesion between the spinal cord and arachnoid, these are usually limited to the surface. By the way, the spinal cord contain extracellular matrix molecules that prevent migration of cells that the spinal cord considers to be "peripheral". For example, generally fibroblasts and Schwann cells (which the spinal cord treats as peripheral cells) injected into the spinal cord will not migrate far from the injection site into the surrounding cord.

    For many years, the Schwab group in Switzerland used the so-called "over-hemisection" model to examine regeneration. However, a number of years ago, they adopted our contusion model. I found the Tuzynski paper particularly interesting because they cut into the spinal cord and find that the resultant "scar" does not seem to impede axonal growth in the cervical spinal cord.

    Wise.
    Thank you. In my case it was an AVM that had to be cut out surgically (last option after many embolization attempts). It was done in Phoenix at BNI in 2002. I would think if there was Collagen in there or some kind of a scar it would show on MR, but in my case the MR images looks like a healthy cord now, still I’m incomplete paralyzed from T4. There was some questions regarding tethering just after the surgery but it showed that it was not the case and that there was space between the cord and the spinal channel. I’m reading your comment here regarding carefully closing the dura with great interest and wonder if you know how this was done in the US in 2002 since I have no papers on how this part of the procedure was carried out. The surgeon who did the surgery was Robert (Bob) F. Spetzler. Also, how can future treatments be carried out if “we” don’t know what to treat? Are there better MR equipment nowadays to see more details, I’ve read a bit about PET scan as well, could this also be a way to determine the state of a injured cord. Seems to me like there is a little “don’t know what’s wrong” gap here as for future cures for SCI. PS. Thank you for posting the Tuzynski paper.
    Last edited by Leif; 10-10-2006 at 07:14 AM.

  10. #20
    Are there histology/pathology slides of contused HUMAN spinal cords, enough to make observations? Is there a review paper somewhere on the pathology?

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