Cure for radiation sickness found?

[David Rosignoli]

Not a lot of information on this yet. It is to be published in Science.
Here is a link to a news website that talks about it:
http://www.ynetnews.com/articles/0,7340 ... 14,00.html

(This is an update to a post from:
viewtopic.php?f=7&t=309&hilit=radiation%22#p309

Apparently, it prevents or reduces radiation damage by "suppressing the "suicide mechanism" of cells hit by radiation, while enabling them to recover from the radiation-induced damages that prompted them to activate the suicide mechanism in the first place".

"Injecting the medication between 24 hours before the exposure to 72 hours following the exposure achieves similar results."

Of course, the US defense (and health) department is putting up most of the bill.

Dave

[Dan Tibbets]

I don't know how significant this is. Cell suicide has been known about for decades. If there is now an aviable drug that might be 'safe' and effective it could only be benificial, though not without risks. Programed cell death is one of the body's primary defenses against new cancers forming. So you might be trading acute morbidity and mortality for greatly increased rates of delayed cancers.
Radiotherapy for cancer works because cells that are reproducing rapidly are the most vulnerable. That is why radiation damage to the bone marrow and gut are generally the limiting factor in whole body radiation. Next is probably the nervous system, not the nerve cells themselfs so much as the cells that support them. Trying to temperarily slow the reproduction of the normal cells is one way that researchers have tried to increase the differention and dose tolorance between the normal cells and cancer cells. Efforts have also been made to selectively make the cancer cells more vunerable to programed cell death, which is difficult because this is one of the mechanisms that can lead to the original cancer.

Other than this, the only treatment that I know of that may have some benifit against radiation poisoning, is lots and lots of antioxidents like vitamin C or E. I believe carbon monoxide is the best, if you can get a large enough dose onboard (before or very quickly after exposure as most of the radiation damage would occur within minutes, if not seconds after exposure) without killing yourself. Ionizing radiation acts mostly by hitting water molecules (the most prevelent target in the body) and producing superoxides- H2O2, atomic oxygen, free radicles,etc. that then cause most of the damage to the cells.

Interestingly, hypoxia can have a similar effect. If a person has a cardipulmonary arrest, and he is revived after a few minutes he may not have significant brain damage, lenghten the time and increasing neurological deficets can occur. Some think that most of this damage is not due to the hypoxia itself, but due to the alternative end points of energy matabolism (like lactic acid) that are produced when there is no longer any oxygen aviable. Once oxygen is restored, these side products are reduced with the production of free radicles and this is what causes alot of the damage in these stressed,but not yet dead nerve cells. Because of this, some propose that using large doses of corticosteroids to decrease the production of damaging inflamatory mediators, and keeping the patient in a barbiturate comma for up to several days may limit the damage.


Dan Tibbets

[Chris Bradley]

Dan DT wrote:
> radiation damage to the bone marrow and gut are generally the limiting factor in whole body radiation.

I have wondered on this point before. I have read this is the case also. If it is so, then is a viable treatment for radiation sickness to replace these functions until the body is given half a chance to replace them - namely by intravenious feed of food and replacement red blood cells for as long as it takes until cells regenerate? or do they never regenerate, and is it known that they don't?

[Dan Tibbets]

There are always gray areas. The gut may be more likely to recover as the endothelium can be restored by the few surviveing cells. The bone marrow is often more unforgiving. Aplastic anemia, etc. usually is perminate. With some cancers, If you are confident that tumer cells are not in the bone marrow, you can suck out some marrow, usually from flat bones like the pelvis or sternum ( blood forming stem cells are generally absent from the long bones once you reach adulthood), and transfuse them back after the aggressive chemotherapy and/or radiotherapy is finished. In acute lymphocytic leukemia, one of the most successful treatments consists of killing the patients bone marrow, then transplanting bone marrow from a doner. This could also be used as treatment for restoring blood forming and other immunological funtions from accidental or deliberate nonmedical radiation exposures. The problem is that you would then need to prevent the graft (bone marrow cells) from rejecting the host. The opposite of what normally can happen with organ transplants.

Dan Tibbets

[Chris Bradley]

It all sounds 'do-able', though, and worth a try if the patient is gonna die anyway. Have such interventions ever been tried in radiation exposure cases?