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Mammals can breathe through their intestines (2021)

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Re: Mammals can breathe through their intestines (2021)

#141

Post by pfdietz »

azalemeth wrote: post #42

One other "fun" use of perflurocarbons (like fluorinated crown ethers or cyclo-alkanes) is that, containing large amounts of 19F, they are MRI visible. So, you can directly image the compound in the lungs leading to some really striking images [1, 2] while they are in the gaseous phase, or indeed in the liquid phase when one lung is partially inflated. I think that some compounds like these have been proposed for use…

One can also do that with nuclear spin polarized 3He or xenon. The nuclei of these isotopes are sufficiently shielded from the environment that polarization (induced with circularly polarized light scattering off alkali vapor mixed with the inert gas) survives for quite a long time. The polarization is orders of magnitude stronger than that induced by magnetic fields in ordinary NMR.

Re: Mammals can breathe through their intestines (2021)

#142

Post by andrew_ »

dTal wrote: post #72
yellowapple wrote: post #36

Earlier quoted context omitted.

The fact that it was an actual rat actually submerged in actual perfluorocarbons and actually breathing the stuff still blows my mind.

Cameron seems to make a big deal of "the rat really survived" (5 rats, in fact), glossing over the fact that the shocking animal cruelty was also real. It's rather hypocritical to pride yourself on the realism of the scene, while cutting all the parts where the rats defecate from panic.

I'd genuinely like to see some objective information about the scene and how it qualifies as animal abuse. The AHA pretty closely monitors scenes with animals and has since the 1940s [1] albeit the rules and regs it follows have continually been improved upon. I understand that there are extenuating circumstances, like the tiger nearly drowning in the "Life of Pi," but from what I can tell, they mostly get it right. After looking for a good amount of time, I'm yet to find a substantiated account of how the rat in "Abyss" was subject to abuse. I understand how the scene might feel but feelings don't equate to actual events.

[1] https://en.wikipedia.org/wiki/American_Humane#Work_in_the_fi...

Re: Mammals can breathe through their intestines (2021)

#143

Post by gxt »

tibbydudeza wrote: post #57
buryat wrote: post #32

Earlier quoted context omitted.

why is it risky?

Red blood cells are meant to travel into capillaries so must deform but will shear easily when subjected to stress which activates clotting action - mechanical pumps still cannot replicate the pumping action of heart.

How has medical science never heard of bellows?

https://en.m.wikipedia.org/wiki/Bellows

Re: Mammals can breathe through their intestines (2021)

#144

Post by wolfram74 »

dTal wrote: post #93
Andrew_nenakhov wrote: post #78

Earlier quoted context omitted.

You better not know what else scientists do to rats. And please, don't even start on the argument that they do it for science and not for entertainment. Entertainment in the form of science fiction is crucial for inspiring new generations of scientists.

It sounds like the next generation of scientists could benefit from inspirational films showing less animal cruelty.

If you insist on knives without any blood, you'll be looking for a very long time.

Re: Mammals can breathe through their intestines (2021)

#145

Post by dTal »

andrew_ wrote: post #142
dTal wrote: post #72

Earlier quoted context omitted.

Cameron seems to make a big deal of "the rat really survived" (5 rats, in fact), glossing over the fact that the shocking animal cruelty was also real. It's rather hypocritical to pride yourself on the realism of the scene, while cutting all the parts where the rats defecate from panic.

I'd genuinely like to see some objective information about the scene and how it qualifies as animal abuse. The AHA pretty closely monitors scenes with animals and has since the 1940s [1] albeit the rules and regs it follows have continually been improved upon. I understand that there are extenuating circumstances, like the tiger nearly drowning in the "Life of Pi," but from what I can tell, they mostly get it right.…

How hard did you look?

From https://www.imdb.com/title/tt0096754/trivia/ (which is incidentally the third Google result[0] for "the abyss american humane"):

"The American Humane Association rated this film "unacceptable" because of the rat that was submerged in oxygenated liquid in one scene."

From the same page:

"James Cameron later admitted that four rats had indeed gone through the procedure without problems; the fifth, however, suffered a cardiac arrest. Fortunately, Cameron was able to revive it through careful chest compressions, and later kept it as a pet."

From the article linked in the original comment:

"Supposedly, the only purpose for the cuts in the sequence was to avoid showing the rats defecating from panic."

And you need only watch the scene to see a rat in enormous distress. I'm not sure what more you want.

[0] The first Google result is an explanation from American Humane themselves that they "were told there were no animals in the film. Therefore, AHA was not aware of the scene involving the rat and was not on the set."

Re: Mammals can breathe through their intestines (2021)

#146

Post by azalemeth »

pfdietz wrote: post #141
azalemeth wrote: post #42

One other "fun" use of perflurocarbons (like fluorinated crown ethers or cyclo-alkanes) is that, containing large amounts of 19F, they are MRI visible. So, you can directly image the compound in the lungs leading to some really striking images [1, 2] while they are in the gaseous phase, or indeed in the liquid phase when one lung is partially inflated. I think that some compounds like these have been proposed for use…

One can also do that with nuclear spin polarized 3He or xenon. The nuclei of these isotopes are sufficiently shielded from the environment that polarization (induced with circularly polarized light scattering off alkali vapor mixed with the inert gas) survives for quite a long time. The polarization is orders of magnitude stronger than that induced by magnetic fields in ordinary NMR.

And then you get the chemical shift differences of the dissolved phases when imaging with 129Xe as well – got to love SEOP and hyperpolarisation techniques in general! :-)

Re: Mammals can breathe through their intestines (2021)

#147

Post by azalemeth »

darkerside wrote: post #80
azalemeth wrote: post #22

Earlier quoted context omitted.

Not a dumb question. What you've just described is an ECMO machine ("extracorporeal membrane oxygenation", related to the surgical machines oft known as a heart-and-lung machine). The act of putting the patient on it is called putting them "on bypass" and involves cutting through some of the most major blood vessels in the body, administration of large doses of heparin as a blood thinner, and a team of about ten to t…

Is the heart that much better of a pump than the ECMO? I didn't realize there was mechanical stress on the blood itself from the ECMO machine.

"Yes", is the short answer. Every ECMO machine I've ever seen uses a [1] peristaltic pump and, despite the use of tubes coated with anticoagulants and with various proprietary bits of chemistry [2] to reduce the size of the inviscid layer and hence shear stresses, the maximum length of time you can spend on them is limited. It's always a downhill battle and typically a "metric shitton" of heparin is infused in order to reduce the risk of thrombus, despite the hemorrhagic risk [3].

All of these things are fine balancing acts but you do not want to be on ECMO for a long time. Similar technologies, such as cardiac LVADs are only licensed in the UK as a bridge to transplant, for example, where a well-defined end-date already exists before putting the patient on them.

[1] https://en.wikipedia.org/wiki/Peristaltic_pump [2] https://www.terumo-europe.com/en-emea/products/tubing-set-pe... [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457945/

Re: Mammals can breathe through their intestines (2021)

#148

Post by tibbydudeza »

gxt wrote: post #143
tibbydudeza wrote: post #57

Earlier quoted context omitted.

Red blood cells are meant to travel into capillaries so must deform but will shear easily when subjected to stress which activates clotting action - mechanical pumps still cannot replicate the pumping action of heart.

How has medical science never heard of bellows? https://en.m.wikipedia.org/wiki/Bellows

Heart is truely an amazing organ - don't think we will get close to a mechanical replacement.

Has multiple chambers, Has chambers that pump sequentially with different pressures and volumes, Never needs to stop for additional lubrication, Never needs to be "charged", Never stops for maintenance, Is powered by oxygen delivered by the red blood cells it is pumping, Is controlled by the body's "proprietary" electro-chemical control system, Is not rejected by the body's internal bio-chemical defense mechanisms, Produces only carbon dioxide as waste, delivers that waste to red blood cells, Doesn't have a single rough or chemically reactive surface, Forms perfect in-line seals around each chamber without crushing red blood cells, Never leaks a single drop, Doesn't retain any fluid in the chambers, Doesn't allow "backward" flow, Has a pump action and pressure that are strong enough to circulate blood up from your toes, but delicate enough to prevent damaging any red blood cells or capillaries

Re: Mammals can breathe through their intestines (2021)

#149

Post by ararar »

mbrundle wrote: post #2

This reminds me of the scene in The Abyss where the rat is forced to breathe in oxygen-rich perfluorocarbons[1]. I think this idea of introducing oxygen through perfluorocarbons has been explored but not sure it’s made much headway in humans to date [2]. This paper seems like a clever idea to introduce the liquid anally where oxygen can diffuse through the linings, and to also use same liquid (because of its viscosit…

Why can't this be repurposed as a lung cleanse? I imagine that heavy smokers' lungs (or coal miners') could benefit from a wash and rinse, perhaps with some vibration assistance. With a medical team standing by to resuscitate.
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