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05/02/2007 02:51 AM ID: 62150 Permalink   

Not Dead Yet!


Researchers at the University of Pennsylvania have discovered that cells do not expire promptly when the heart stops but instead take several hours to die once cut off from their blood supply. However, cells die quickly if oxygen is reintroduced.

Researchers don't know why cells die when oxygen is reintroduced. They speculate that the body can't tell the difference between a diseased cell and one that is being "reperfused" with oxygen and so destroys the reviving cell in self-defense.

These findings may radically change how cardiac arrest patients are treated. "Suspended animation" would be induced, followed by slow oxygenation. A test on 34 subjects had an 80% success rate. Currently the success rate is apparently 15%.

    WebReporter: awhompbamboom Show Calling Card      
ASSESS this news: BLOCK this news. Reason:
Great story and reporting

: ]
  by: Zmethod     05/02/2007 05:55 AM     
good story, really... interesting and all that... just one thing...

"Researchers don't know why cells die when oxygen is reintroduced."

Maybe I'm reading it wrong, but I think the source says why. It says that "Biologists are still grappling with the implications of this new view of cell death" but it goes on to say that "not passive extinguishment, like a candle flickering out when you cover it with a glass, but an active biochemical event triggered by "reperfusion," the resumption of oxygen supply. The research takes them deep into the machinery of the cell, to the tiny membrane-enclosed structures known as mitochondria where cellular fuel is oxidized to provide energy. Mitochondria control the process known as apoptosis, the programmed death of abnormal cells that is the body's primary defense against cancer. "It looks to us," says Becker, "as if the cellular surveillance mechanism cannot tell the difference between a cancer cell and a cell being reperfused with oxygen. Something throws the switch that makes the cell die."
  by: tellgar     05/02/2007 06:02 AM     
  This is new?  
To who exactly?

Certainly anyone who's ever seen a bloody defibrilator used on ER.

Of course your cells dont all die immediatly after your heart stops.
  by: Gogevandire   05/02/2007 09:24 AM     
  When you're severely hypoxic  
As in, breathing very thin air and not getting enough oxygen, if you're suddenly given oxygen your symptoms temporarily worsen. Could be a similar thing.
  by: p_g_chris   05/02/2007 09:29 AM     
  Thanks Goge....  
While I'm sure we all knew that cells don't immediately die, I think this new discovery will result in changes to ventilation procedures during cardiac arrest/resus efforts. Who would have guessed that giving the body more oxygen would cause damage?
  by: rapscaLLion   05/02/2007 09:33 AM     
  @ rapscal  
it definatly did damage to me... i almost passed out resuscitating someone before.

but excellent find awhompbamboom.
  by: DarkAngelJG     05/02/2007 01:28 PM     
"Of course your cells dont all die immediatly after your heart stops."

I seriously don't know why you even bother. Some of the cells in a person that is in cardiac arrest and fibrillating are dead which is the reason their heart is not contracting properly to begin with. As anyone that knows biology would imagine this is due to ischemia.

Not ALL the cells are dead because the heart is not functioning properly, but good try.
  by: kuhl   05/02/2007 06:06 PM     
Thanks for noting that! Yeh, I qualified that passage because as I read it, the researchers know *what* happens, but they don't know why or exactly how. The article was precise with its description of apoptosis, but then Becker is quoted as saying "It looks to us as if...", and continues with "Something throws the switch that makes the cell die". Something? I concluded that the sudden change from precise to vague signalled that they believed they were missing some information.

I think what surprised the researchers is how long the cells survive after being deprived of their blood supply. It had been assumed that death occurs fairly quickly throughout the body. According to this article, six hours after the heart had stopped beating, little change was observed, so technically people who have once been written off as meat could still be revived. Furthermore, people revived using these methods could avoid some of the brain damage often associated with this type of problem, as the brain shuts down early to conserve oxygen.

One significance of this research, IMHO, is that it could challenge our current legal definition of death, and cause people to rethink DNR clauses. We could see surgeons beginning to operate on "dead" people, repairing damage prior to resuscitation.

Thanks, Tellgar! And thanks, everyone. This is my first article for ShortNews, so I've got some rope-learning to do.
  by: awhompbamboom     05/02/2007 08:48 PM     
  okay I figured it out.  
Contact these scientists and tell them the reason that the cells apoptose is because the cell has accumulated large amounts of ADP during the lack of perfusion (hypoxia) due to the use of anaerobic glucose pathways. Then tell them that the molecular mechanism to reduce ADP amounts is to convert that molecule to hypxanthine which is then converted to large amounts of free radicals (O2) upon repurfusion.

And of course this goes hand in hand with the destruction of the K and Na gradient due to the lack of ATP. This would cause an influx of Ca and only aid in the molecular machinery that is apoptosis.
  by: kuhl   05/03/2007 09:39 PM     
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