US Scientists create zombie dogs

Excerpt: "U.S. scientists have managed to revive dead dogs to life, by using a technique similar to cryogenation, in which the dogs' blood was drained and replaced by a cold, saline liquid. A couple of hours, their blood was replaced, and an electric shock brought them back to life with no brain damage. The technology will be tested on humans within the next year."

Here's the discussion

So, does this mean that we can watch Resident Evil 3 without having to enter the cinema?

From what I recall, during drowning or suffocation, brain damage occurs in humans quite soon (10 minutes?). How is it that this process negates the lack of oxygen to the brain, allowing no damage to occur?

The 10 minute limit is for slow suffocation at normal temperatures. Two things happen:

- First, many of the tiny valves controlling the distribution of blood in the brain capilaries shut, trying to route the remaining oxygen to the neurons controlling things like breathing and heart rate.

These valves are tiny muscles, which, once contracted, require power (from metabolization) to reopen. Let them be oxygen-starved for too long - about ten minutes - and they get stuck closed. Then, even once oxygen is restored, the blood remains cut off to the areas they control. (It does no good to raise the blood pressure to try to force blood past them: You'll blow the plumbing before they leak. Massive stroke.)

- Second: As with the muscles, the neurons have continuous chemical reactions going on that cause damage that must be cleaned up by active, powered, systems. Turn down the oxygen while leaving the temperature up and the cleanup systems fail while the damage mechanisms continue. (Firing the nerve uses up additional power, making the problem worse.)

Let this go on for more than half an hour or so without turning the air back on and the damage gets ahead of the nerve's ability to repair it - causing cell death. That ruptures the cell and releases a glutamate - which tends to force other nearby nerves to fire, consuming their resources and speeding their death, in the "glutamate chain reaction". This easily gets started in regions of the brain fed by still-shut-off plumbing. But with enough glutimate dumped it can spread to nearby areas that have adequate oxygen - because it's not adequate to keep ahead of the massive firing and cell exhaustion.

The first mechanism sets the normal time limit. But the second is the final catastrophe.

But diving sets up a condition much like suffocation upon resurfacing: Swimming underwater pressurizes the gas in the lungs, and the organism can remain active for some time before it starts to run out of oxygen. But then it takes time to get back to the surface - and the lowered pressure on the ascent causes oxygen levels in the blood and tissue to crash. Not good.

Evolution came up with a workaround: The "mamilian diving reflex", so called because it's characteristic of all mamals - happened a LONG time back.

When the reflex detects a deep dive (cold on the skin - especially on the back of the neck, I think), it modifies the valves' reaction to overall oxygen shortage: Instead of shutting off blood to "unimportant" (for respiration) parts of the brain, it causes ALL the valves to OPEN. Then if they stick they stick open. This risks speeding respiratory failure. But once (if) oxygen is restored, it allows it to reach ALL the brain. Get oxygen back before the cells start dying (after a half hour or so) and they all get the power they nead to clean up and get on with life.

So if you drown in COLD water you can be breathing-stopped for a half-hour or a bit more and still be restarted with no long-term brain damage.

This treatment seems to extend on that: Flooding with cold saline will activate the diving reflex, sticking the valves open. Then the rapid oxygen loss will shut down all energy-driven metabolism - both the repair and some of the damage-makers.

Meanwhile, the deep cooling of the tissue (to essentially refrigerator temperatures) will slow the other damaging chemical reactions, just as refrigeration slows meat spoilage. (It IS slowing meat spoilage! And 7C is about 45F, close to the 40F recommended for refrigerator settings.) This is probably the main factor in getting past the half-hour limit on cold-drowning.

Separate storage of the blood allows the replacement fluid to be optimized to cool the rest of the body at a more rapid rate than could be accomplished with blood and to maintain pH and osmotic pressure under the abnormal temperature conditions - along with rapid re-heating just before the blood is replaced. It also reduces or elminates clotting, breakdown of the red cells (which would otherwise dump iron and copper into the tissues, causing free-radical damage later), and possibly changes to the immune-system cells (that might cause lowered reaction to infection and/or auto-immune and allergic problems upon revival). These factors probably help as well.

What else? It seems that the soviets were doing it in the 40's

So, looks like those who think that souls exist have yet another thing to debug, don't they?

But nevermind, those people will never change their minds anyway. Let us focus on the practical applications of this technology.

I don't think it is a good idea to resurrect people. The population of the planet increases, people will keep reproducing, and death is a part of life.

Hmmm.. what else? resurrecting dead pets? Doubt it.. This should be too expensive for an average family to afford.

Maybe... this is the exact thing they do to the crew of a starship that travels far far away... [this will be used before time travelling, black holes and teleportation are studied well enough]

Certainly, this is a step forward, but I fail to find a good use for it, except for the long distance space travels and accidents (where a healthy person can still be saved).