Posted on 04/21/2005 5:43:02 PM PDT by anymouse
Mice forced to breathe hydrogen sulfide -- known best for its rotten egg smell -- go into a kind of suspended animation, U.S. researchers said on Thursday in a finding that may help save human lives.
Although hydrogen sulfide gas is toxic in high doses, it may activate some of the mechanisms that cause other animals to go into hibernation, they wrote in this week's issue of the journal Science.
Finding a safe way to do this in humans could lead to new ways to treat cancer and prevent injury or death from blood loss, or help people undergo and recover from surgery better, said the team at Fred Hutchinson Cancer Research Center.
"We are, in essence, temporarily converting mice from warm-blooded to cold-blooded creatures, which is exactly the same thing that happens naturally when mammals hibernate," said Mark Roth, who led the study, in a statement.
"We think this may be a latent ability that all mammals have -- potentially even humans -- and we're just harnessing it and turning it on and off, inducing a state of hibernation on demand," said Roth, a biochemist.
Bears do it, amphibians do it, and people occasionally hibernate, too. Many cases have been documented of small children, and the occasional adult, reviving from near-drownings in icy water after their body temperatures had dropped and they had stopped breathing for more than an hour.
"Understanding the connections between random instances of seemingly miraculous, unexplained survival in so-called clinically dead humans and our ability to induce and reverse metabolic quiescence in model organisms could have dramatic implications for medical care," Roth said.
"In the end I suspect there will be clinical benefits and it will change the way medicine is practiced, because we will, in short, be able to buy patients time."
In the mice, Roth's team tried doing it chemically with toxic hydrogen sulfide, a colorless gas made by the breakdown of sulfur compounds. In high doses it kills by stopping cell metabolism.
"When mice were exposed to 80 parts per million of hydrogen sulfide, their oxygen consumption dropped 50 percent and their carbon dioxide output dropped by 60 percent within the first five minutes," they wrote in their report.
"If left in this environment for six hours, their metabolic rate dropped by 90 percent."
Lowering metabolism reduces the need for oxygen. If this could be replicated in humans, it could help buy time for critically ill patients on organ-transplant lists and in operating rooms, emergency rooms and on battlefields, Roth said.
Cancer treatment might be improved, too, he said. If healthy tissue can be put into suspended animation, it might be possible to raise doses of radiation to kill tumor cells, Roth said.
"Right now in most forms of cancer treatment we're killing off the normal cells long before we're killing off the tumor cells. By inducing metabolic hibernation in healthy tissue we'd at least level the playing field," he said.
Hydrogen sulfide is toxic in high doses but the mice did not appear damaged in any way, Roth said.
"The cool thing about this gas we're using, hydrogen sulfide, is that it isn't something manufactured that we're taking down from a shelf -- it isn't 'better living through chemistry' -- it's simply an agent that all of us make in our bodies all the time to buffer our metabolic flexibility. It's what allows our core temperature to stay at 98.6 degrees, regardless of whether we're in Alaska or Tahiti," Roth said.
Does that mean a judge may order you killed if you are in suspended animation?
'it could help buy time for critically ill patients on organ-transplant lists and in operating rooms, emergency rooms and on battlefields'
If only the Kursk had this.
All you have to do is live in paper mill country..
Well if it works it would be pretty cool. Not sure if I want to try it out just yet though......
So far only in Florida.
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