Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: nilmot on 31/08/2004 22:52:16
-
I recently read in the NewScientist that they have discovered a new way of keeping stroke patient alive for longer when they have a stroke. (All the detail I made is referenced from the 7 August edition)
This is a genetic therapy method, they haven't actually start practicing this method yet because it is still quite new and not fully tested (only on mouse). What they usually faced with is a patient had a stroke somewhere in the body thus blocking the oxygen supply, tissue die of oxygen starvation. In respond the body usually produced a protein called heme-oxygenase-1 abbreviated to HO-1 to produce oxygen for the tissue. But the problem is it normally takes about 6~12 hours for the body to produce enough HO-1 to get a high enough O2 level.
"Researcher used a virus to insert a souped-up version of the HO-1 gene into the cell and this gene is swtiched on when the O2 level drops."
They have inserted this gene into heart, liver, and muscle tissue of a rat and cut off its blood supply, these tissue amazingly lived up to an hour obviously there are damages to the tissue but is greatly reduced compared with normal circumstances. This could be practical when there are patients whom are likely to have an attack or stroke and survival rate in surgery will increase.
Tom
-
That's really cool. Any idea of adverse effects of excess HO-1 in cells where bloodflow is normal? Or does the gene only activate in conditions of low oxygen? Also, what about brain tissue? Aren't a lot of the effects of stroke caused by the loss of blood to parts of the brain?
This message brought to you by The Council of People Who Are Sick of Seeing More People
-
That's what I'm think of, it doesn't mention in the article, but I don't think it will have any effect because it is naturally in the body well in a slightly different version.
Further testing is yet to be done, I see if a can find anymore on this on the web.
Tom
-
Would athletes be able to perform better if they had that sort of therapy?
Tim
-
Mmm... interesting point. I've been looking around on the web is it seem hard to find anything on this or it could be that I'm not searching properly.
It's definitely possible, the gene might only work when the oxygen level is low enough to alert the body. Vigorous exercise? Depends on how hard you work your muscle I guess..
Tom
-
That sounds good, but where is the oxygen coming from? In a stroke or HA victim, it wouldn't take much O2 to make a big difference in the survival of the tissue. I would think that in an athlete, the supply would need to be sustained for a longer period and provide a larger amount to enhance performance. Am I missing something?
----
John - The Eternal Pessimist.
-
The reason when a cell dies when lack in oxygen is because respiration stops, no ATP produced.
There is a protein pump in cells called Na+K+ ATPsynthase which keeps the balance of these 2 ions in a ratio of 2K+ inside the cell and 3Na+ outside of the cell (could be the other way round).
I'll do this in step by step method:
1.When there are no ATP the pump stops working the balance is out, Na+ start to enter the cell
2.With accumulation of Na+, Cl- is also drawn in to cancel the charge but it makes salt.
3.Water is drawn in to dilute the salt. Then cell swell and dies.
This applies to when an organ's blood supply is cut off either from a stroke or the surgeon is doing a organ transplant and have to prevent the above from happening.
Back to your point John which I think is quite rightly point out that exercises take an awful lot more O2 and ATP. Evey single muscle 'cell' contraction uses up 1 ATP and there are thousand of muscle cell if not more.
Other biologist in this forum can provide more information on that I'm not very good at that yet. (Haven't study it)
Tom