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Face transplant recipient’s donor face now failing

latimes.com

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Re: Face transplant recipient’s donor face now failing

#91

Post by PeterisP »

onemoresoop wrote: post #80
peterlk wrote: post #12

Earlier quoted context omitted.

I just finished up an introductory biology lecture series, and this suddenly makes less sense to me than it did before. What is it about the foreign cells that is identified as foreign by the host cells? The cells ought to be remarkably similar. They're human, with the same function/pluripotency using the same protein interactions. So why attack it?

My understanding is that most cells in the human body regenerate. What I don't understand is how cells that are part of the transplant regenerate. Do they use the host or the transplanted DNA to regenerate?

Cells (re)generate by splitting, there's no other way. For non-mobile tissue, the tissue regenerates itself from whatever DNA the cells in that tissue have locally. There are some types of cells that are "manufactured" in one place and "shipped" throughout the body (e.g. blood cells in bone marrow) but for the transplanted tissue any new cells would still have the donor DNA forever.

Also, that applies for chimeric humans that happen to have two different DNA sets from two different fertilized eggs; some parts of their body will forever have different DNA than other parts.

Re: Face transplant recipient’s donor face now failing

#92

Post by PeterisP »

paggle wrote: post #77
robohoe wrote: post #65

Earlier quoted context omitted.

He’s supposedly dead [0]. https://www.vnews.com/Man-Convicted-of-Maiming-Vermont-Woman...

Cases like this are why torture should be a legal sentence for the worst crimes where guilt is not in doubt.

Thing is, there's no such thing as "where guilt is not in doubt". We have a legal standard of "beyond all reasonable doubt", and still we know for certain that this standard, when applied to its full extent as it gets for death row convicts with all the multiple appeals courts, it still manages to convict a nontrivial number of innocent people.

So the judgment on whatever should happen in case where guilt is really not in doubt must be reserved for omniscient infallible divine beings, as we the people simply are not capable of implementing a process that's able to determine when guilt is not in doubt, as all practical experience shows that we've tried and failed and failed and failed to do so.

Re: Face transplant recipient’s donor face now failing

#93

Post by lr4444lr »

rcthompson wrote: post #60
radlad wrote: post #20

Earlier quoted context omitted.

> Any time we do any transplant immunosupressants are given to the recipient for the rest of their life, but this only slows the inevitable. Is this true that it is inevitable? My understanding, from my girlfriend attending medical school (only M1), is that for many types of transplants, when immunosupressants are taken properly, it is unlikely that the organ will ever be rejected. For example, only 10-20% of patient…

Even if there is no acute rejection event, long-term accumulation of damage from the host's immune system attacking the graft at a low background level is still very likely. Immune suppression has to walk a tightrope that in addition to being very thin is also constantly moving around. Each time you get sick, if your immune suppression is too aggressive, you might just die. If it's not aggressive enough, the pro-immu…

There was some talk a while back about using a modified form of HIV to suppress immune response for transplant recipients. Any update on that?

Re: Face transplant recipient’s donor face now failing

#94

Post by sushid »

markkat wrote: post #66
puranjay wrote: post #48

Earlier quoted context omitted.

I'm a little curious how something like this works within the economic framework of a startup. How do you reconcile the inherently long-term nature of your business (I might need my stem cells in a decade or two) with the inherent instability of a startup (you might go out of business within 3 years)?

The annual storage fees ($250/yr) cover our banking costs. The banking needs little more than invoicing to remain viable, and with the numbers we have banked, it could survive as a stand-alone entity, or would be an asset that could be acquired by another banking service. My cells are in there, as are those of many of my family members. I want them available 20 years from now. Of course, we aspire to mature beyond a…

What is the value prop for extracting and storing stem cells now vs. extracting them later? Is it just that you’ll have to extract less bone marrow now vs later? Isn’t there a decline in quality and quantity of viable stem cells when they’re stored?

Re: Face transplant recipient’s donor face now failing

#95

Post by capnslowish »

sandworm101 wrote: post #31
arkades wrote: post #23

Earlier quoted context omitted.

“Only 20%” and “unlikely to ever be rejected” are worlds apart. Modern immunosuppressive therapy for, for instance kidneys, has dropped the five year acute rejection rate from 50% to 20%. About 8-10% in the first year. You can get a 5% 10-year non-rejection rate only in the most hand-picked groups (adheres to meds, no underlying systemic disease, and no chronic nephropathy). That sub-population exists, but it’s prett…

People without underlying disease generally dont need or get replacement organs. These are all complex cases. Only in the most rare of circumstances does an otherwise totally healthy person need a new kidney.

Focal glomerulosclerosis destroys kidneys in a completely healthy person.

Re: Face transplant recipient’s donor face now failing

#96

Post by insulanus »

PeterisP wrote: post #91
onemoresoop wrote: post #80

Earlier quoted context omitted.

My understanding is that most cells in the human body regenerate. What I don't understand is how cells that are part of the transplant regenerate. Do they use the host or the transplanted DNA to regenerate?

Cells (re)generate by splitting, there's no other way. For non-mobile tissue, the tissue regenerates itself from whatever DNA the cells in that tissue have locally. There are some types of cells that are "manufactured" in one place and "shipped" throughout the body (e.g. blood cells in bone marrow) but for the transplanted tissue any new cells would still have the donor DNA forever. Also, that applies for chimeric hu…

> Also, that applies for hymeric humans

Seems like this: https://en.wikipedia.org/wiki/Chimera_(genetics)

Re: Face transplant recipient’s donor face now failing

#97

Post by apathy »

mkl wrote: post #71
alan-crowe wrote: post #51

Earlier quoted context omitted.

Additionally, if the immune system would just check that the cell is human, then humans would be vulnerable to contagious cancer, such as the facial tumor disease suffered by Tasmanian Devils https://en.wikipedia.org/wiki/Devil_facial_tumour_disease

Humans almost certainly are vulnerable to contagious cancer (there are a few known in other species: https://en.wikipedia.org/wiki/Clonally_transmissible_cancer ) . We just haven't acquired/discovered any yet.

HTLV, EBV, HPV

you better believe we have! It’s just rare (thank goodness).

Re: Face transplant recipient’s donor face now failing

#98

Post by insulanus »

echelon wrote: post #74
peterlk wrote: post #12

Earlier quoted context omitted.

I just finished up an introductory biology lecture series, and this suddenly makes less sense to me than it did before. What is it about the foreign cells that is identified as foreign by the host cells? The cells ought to be remarkably similar. They're human, with the same function/pluripotency using the same protein interactions. So why attack it?

> I just finished up an introductory biology lecture series, and this suddenly makes less sense to me than it did before. The immune system is one of the most complicated and wonderful pieces of biology. It's also scary in the ways that it can malfunction and the challenges it presents to modern medicine. > What is it about the foreign cells that is identified as foreign by the host cells? The MHC system is a major d…

You post made me wonder about a lot

> Unfortunately, the MHC proteins are themselves a highly reactive antigen thahttps://www.airships.net/hindenburg/interiors/t triggers the immune system. Luckily, the body learns during a process called "negative selection" to cull any immune cell receptors that recognize your own MHCs:

This is very interesting that this process is split into two separate domains / privilege levels. That way you can't have a fork bomb that would overwhelm the MHC production process.

> Unfortunately, your body doesn't know the shape of MHC proteins from donor tissue and can't learn to kill any TCRs that match.

Maybe we'll combat this in the future by finding a way to donate or genetically engineer a whole bone from the organ donor, thus having bone marrow matching the donated organ. If we could get localized immune suppression on only those parts, that would be cool. I guess those leukocytes would be attacked immediately.

> https://en.wikipedia.org/wiki/V(D)J_recombination

Wow.

Re: Face transplant recipient’s donor face now failing

#99

Post by PeterisP »

insulanus wrote: post #96
PeterisP wrote: post #91

Earlier quoted context omitted.

Cells (re)generate by splitting, there's no other way. For non-mobile tissue, the tissue regenerates itself from whatever DNA the cells in that tissue have locally. There are some types of cells that are "manufactured" in one place and "shipped" throughout the body (e.g. blood cells in bone marrow) but for the transplanted tissue any new cells would still have the donor DNA forever. Also, that applies for chimeric hu…

> Also, that applies for hymeric humans Seems like this: https://en.wikipedia.org/wiki/Chimera_(genetics)

Yep, that's the correct term, English isn't my main language.

Re: Face transplant recipient’s donor face now failing

#100

Post by paggle »

PeterisP wrote: post #92
paggle wrote: post #77

Earlier quoted context omitted.

Cases like this are why torture should be a legal sentence for the worst crimes where guilt is not in doubt.

Thing is, there's no such thing as "where guilt is not in doubt". We have a legal standard of "beyond all reasonable doubt", and still we know for certain that this standard, when applied to its full extent as it gets for death row convicts with all the multiple appeals courts, it still manages to convict a nontrivial number of innocent people. So the judgment on whatever should happen in case where guilt is really n…

There can be standards of proof higher than the current ones for torture. For example, another jury whose instructions are “beyond all doubt.” Both juries would need to come back guilty for the torture. Of course no system is infallible, but there is also off the books torture in the current system.
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