Retina is a good example of this. Zebrafish can regrow damaged retina, but while mammals have the same stem cells (Muller glia), they dont repair the retina, but form scar tissue. There is a lot of research and I think they have managed to modify rat genome, so that their retina has showns some repair abilities. The problem is that it often causes tumors.
I have other retina permanently damaged, and suffer from double vision when looking small objects like text.
Some aging mechanisms like telomeres are also mechanisms to prevent cancer by limiting cell division.
It looks like one of the optimization edges walked by evolution is a conflict between longevity and the ability to repair and regenerate versus not getting cancer.
It’s easy to make human cell lines immortal, but that will kill you.
One route I can imagine to radical life extension is to start by editing the genome to introduce much more robust but different anti cancer adaptations. Then start turning regenerative stuff and things like telomerase back on.
I've learned about the cancer vs tissue repairability (or cancer vs heart/cardiovascular failure) from Joe Rogan's podcast with Bret Weinstein (or his brother, don't remember).
It's visible in death causes - pretty much all non accident deaths are divided between cancer and heart attack.
A very interesting thing discussed in that podcast was about transgenic (or maybe all?) lab mice bred in USA. These mice are used for initial screening for nearly all drugs. And due to some error and ignorance, unbeknownst to most people using the mice, nearly all mice are predominantly on one side. (Sorry, don't remember which). They just all come from the same family.
Which means that nearly all drugs in the past few decades are skewed toward either giving people cancer or heart attacks.
This is due to mice being extra resistant to one of these and therefore not properly signaling when the drug is likely to give people heart attacks or cancer.
Yep, the unfortunate flipside of "let's use stem cells to rebuild stuff" is always "let's use stem cells to give us cancer". Technology might help alleviate the cancer part compared to blind evolution, hopefully.
I’m surprised this does not mention humans can grow back the tips of their fingers (past the white part of cuticle) https://www.npr.org/sections/health-shots/2013/06/10/1903854...
Supposed to be only kids but I’ve chopped off a few mm by accident it came back as an adult or I can’t tell the difference.
Does your fingerprint look normal? When I was a kid I was goofing around with a pair of scissors and lopped off a good chunk of the pad of one finger. Thirty years later my fingerprint looks like a bunch of little dots at that location. The ridges never grew back properly.
The exact same thing happened to me. I chopped off a good half a cm with an axe when splitting firewood about 5 years ago. After no less than 6 months there wasn’t any sign of the mutilation.
2 years I ago I sliced maybe 1.5mm frommy thumb-tip; when taking off the bandage, I could clearly see the "straight cut" and that some material was missing.
Lol, I once sharpened my knives and went to cook. During the prep I said, "wow I wonder how sharp the knife is", next thing you know, i cut about 1/4" of my finger tip off, right through the finger nail with zero resistance.
Besides the blood getting everywhere and needing superglue to stop it, it grew back completely fine.
You shouldn't really sharpen kitchen knifes too sharp. And even if they're not super razor sharp (cutting a finger with no resistance), you should still warn people new to your kitchen or even family members/regular users right after each re-sharpening.
Additionally, too low angle will make the knife very suspectible to blunting and/or require constant drawing on the sharpening steel¹. Unless you have super high quality steel like Japaneese knifes or some craft smith knifes.
Butcher knifes, to be used along with a chainmail glove, are fine. Just don't test their sharpness on body parts. Or use them to shave a bit of hair, but very carefully.
It's totally true, and more so true in a slaughterhouse. Blunt knifes cause strain injuries on joints, and make people use much more force than necessary, which comes at a loss of precision. And then it turns out, that with enough force, a semi-blunt knife will still cut through a kevlar anti-cut glove and hit fingers.
BUT!, once the knife is sharp enough for a job, and I mean for comfortable work, not just barely enough, then it's enough.
Giving somebody who never held a sharp knife in their life a knife that is so sharp it will cut their fingers without them feeling it (or even close to that sharp) is like telling somebody to run a coding agent on their system and not in a VM. Things can get bad really fast.
Most people (at least in central Poland where I come from) used semi blunt knives* for everything. Some would have a household knife sharpener or maybe even low quality sharpening steel like the ones you get in a knives set. Maybe they or their grandma had a butcher in the family. They will have nice sharp knives that can cut tomatoes without crushing them.
But with a knife that is sufficiently thin, a throwaway leather belt, a little skill and an hour or more of time, you can get a mirror-like polished blade that is so sharp you can amputate limbs in seconds. Just need to go through the joint at a correct angle.
That's how our grandfathers shaved.
* just realized I was typing plural for knives wrong - with an 'f'
"During the prep I said, "wow I wonder how sharp the knife""
Is there something missing in the story? (drugs, coercion, self harm ideas, anything)
I have had my fair share of avoidable cuts, but none of them included looking at the edge before happening.
In your first comment, replace “until today” with “since then” and you’re good!
“Until today” is one of those English phrases that is particularly unfair on non-native speakers. You know “until” and you know “today” and so it’s completely natural to combine them in the way you did.
But as ever, English is dumb and annoying and hard work, all at the same time.
In a study they figured out that organs seem to have an electrical potential range as a signature/command for stem cells for which organ to build and where.
In a frog they were able to grow legit eyes in the gut just by artificialy inducing a certain voltage in that area. No need for any cell transplantations: the voltage really seems to be the only signal needed.
This might also be how it might be done in the future in humans: block scar tissue then induce voltage with the signature of the organ you wish to regrow.
The trick is to make regeneration fast enough to heal the wound without making fast enough to cause cancer. Maybe even supported by provisional fibrosis.
Like the way slime molds solve mazes: explore every possible path in parallel, and push growth in all areas with greater nutrient gradients. Not by sensing any gestalt clues, like symmetries in the maze design.
"I don't know how it works, so it must be fake news."
To be fair, the person being skeptical is just a surgeon, this is not a peer-reviewed study or anything actually scientific.
Your NPR link even shows that scientists realize there are still unknowns:
> "We think that nail stem cells may a have a special function to induce the whole regeneration process, including nerve attraction and growth of the bone," Ito say.
A cursory search seems to say that typical regrowth of a nail takes 4-6 months, but Spievak claimed his only took 4 weeks.
Can we say definitively that his "pixie dust" had nothing to do with it? I don't think so. Can we say it did have something to do with it? Also unknown... but the answer right now IMO certainly isn't a scientific "no."
If it worked on humans 13 years ago, then by now it would have worked on a human who was not sibling to the inventor, in a way not essentially identical to life without it.
In the whole Christian tradition, God/Jesus generally does not go for organ or limb regeneration. Two counter examples are a healed ear in Luke (but this may well have been resumption of hearing? details are a little light), and then a single Spanish example in the 1600s.
For His own mysterious reasons, He simply doesn’t go in for that stuff, however much intercessionary prayer ends up in His inbox.
not an amputee, but he did heal a man with a withered or malformed hand in Matthew 12. he also healed plenty of cripples, so I don’t think it’s a stretch to think that some or many of them were missing limbs.
I think to claim that 2000 years ago there was one person who performed miracles and/or healed people that nobody else could, with no actual evidence it was done and nobody else has been able to do it since, you need a better response to someone questioning it than “oh were you there? prove it didn’t happen.”
even the Jews of the time that did not believe or follow Jesus wrote that he performed signs. They claimed it was sorcery.
in Folio 43a of Tractate Sanhedrin of the Babylonian Talmud as follows:
‘It is taught: On the eve of Passover they hung Yeshu and the crier went forth for forty days beforehand declaring that "[Yeshu] is going to be stoned for practicing witchcraft, for enticing and leading Israel astray.”’
The relevant portions of the Bible record that the Jews of the Sanhedrin acknowledged the signs and miracles but said it was by the power of Satan that he did these things.
They also have countless records proving hundreds of thousands of women were witches, with ironclad proofs such as “if we stab them they scream so they must be witches, off to the pire” or “throw them bound in the water, if they float it means they’re evil because water (baptism) rejects them so they’re witches -> burn.”
He's not unique though. Quite a few people are on record for performing miracles in front of large audiences. Seemed like it was all the rage around this time period.
Vespasian apparently healed blind people in Alexandria. Apollonius of Tyana had a very colourful life performing all kinds of magic. Honi the Circle Maker was bringing the rain over in Judea.
Must've been something in the water other than lead!
This is ironic. They didn’t say they believe. You offered your belief that you know something that happened long ago (extraordinary claim), and they are naturally curious how you could know that. If you’re a time traveler or whatever we’d be quite interested to hear more.
Retina is a good example of this. Zebrafish can regrow damaged retina, but while mammals have the same stem cells (Muller glia), they dont repair the retina, but form scar tissue. There is a lot of research and I think they have managed to modify rat genome, so that their retina has showns some repair abilities. The problem is that it often causes tumors.
I have other retina permanently damaged, and suffer from double vision when looking small objects like text.
Ah, I was wondering the evolutionary reason why those genes would have gone dormant.
Cancer is a sensible answer.
Some aging mechanisms like telomeres are also mechanisms to prevent cancer by limiting cell division.
It looks like one of the optimization edges walked by evolution is a conflict between longevity and the ability to repair and regenerate versus not getting cancer.
It’s easy to make human cell lines immortal, but that will kill you.
One route I can imagine to radical life extension is to start by editing the genome to introduce much more robust but different anti cancer adaptations. Then start turning regenerative stuff and things like telomerase back on.
I've learned about the cancer vs tissue repairability (or cancer vs heart/cardiovascular failure) from Joe Rogan's podcast with Bret Weinstein (or his brother, don't remember).
It's visible in death causes - pretty much all non accident deaths are divided between cancer and heart attack.
A very interesting thing discussed in that podcast was about transgenic (or maybe all?) lab mice bred in USA. These mice are used for initial screening for nearly all drugs. And due to some error and ignorance, unbeknownst to most people using the mice, nearly all mice are predominantly on one side. (Sorry, don't remember which). They just all come from the same family.
Which means that nearly all drugs in the past few decades are skewed toward either giving people cancer or heart attacks.
This is due to mice being extra resistant to one of these and therefore not properly signaling when the drug is likely to give people heart attacks or cancer.
Sorry, don't remember which it is exactly.
Yep, the unfortunate flipside of "let's use stem cells to rebuild stuff" is always "let's use stem cells to give us cancer". Technology might help alleviate the cancer part compared to blind evolution, hopefully.
Teratomas are insane.
https://en.wikipedia.org/wiki/Teratoma
I think presumably Zebrafish aren't prone to retina cancer.
Dinosaur Predation damage? If you life fast, get eaten young, repairs are a waste.
Counterpoint: long-lived mammals. Elephants and whales are both famously long-lived, and oddly low-cancer.
I’m surprised this does not mention humans can grow back the tips of their fingers (past the white part of cuticle) https://www.npr.org/sections/health-shots/2013/06/10/1903854... Supposed to be only kids but I’ve chopped off a few mm by accident it came back as an adult or I can’t tell the difference.
Does your fingerprint look normal? When I was a kid I was goofing around with a pair of scissors and lopped off a good chunk of the pad of one finger. Thirty years later my fingerprint looks like a bunch of little dots at that location. The ridges never grew back properly.
Same. Chopped off the tip of my thumb with an axe, it’s healed but very scarred and fingerprint is not normal.
The exact same thing happened to me. I chopped off a good half a cm with an axe when splitting firewood about 5 years ago. After no less than 6 months there wasn’t any sign of the mutilation.
2 years I ago I sliced maybe 1.5mm frommy thumb-tip; when taking off the bandage, I could clearly see the "straight cut" and that some material was missing.
Until today, it recovered completely
Lol, I once sharpened my knives and went to cook. During the prep I said, "wow I wonder how sharp the knife is", next thing you know, i cut about 1/4" of my finger tip off, right through the finger nail with zero resistance.
Besides the blood getting everywhere and needing superglue to stop it, it grew back completely fine.
You shouldn't really sharpen kitchen knifes too sharp. And even if they're not super razor sharp (cutting a finger with no resistance), you should still warn people new to your kitchen or even family members/regular users right after each re-sharpening.
Additionally, too low angle will make the knife very suspectible to blunting and/or require constant drawing on the sharpening steel¹. Unless you have super high quality steel like Japaneese knifes or some craft smith knifes.
Butcher knifes, to be used along with a chainmail glove, are fine. Just don't test their sharpness on body parts. Or use them to shave a bit of hair, but very carefully.
1: https://www.dick.de/messer/en/sharpening/dickoron-family/dic...
> You shouldn't really sharpen kitchen knifes too sharp
There is a sentence among cooks: "only with a stub/butt knife you cut yourself" - isnt this true anymore?
It's totally true, and more so true in a slaughterhouse. Blunt knifes cause strain injuries on joints, and make people use much more force than necessary, which comes at a loss of precision. And then it turns out, that with enough force, a semi-blunt knife will still cut through a kevlar anti-cut glove and hit fingers.
BUT!, once the knife is sharp enough for a job, and I mean for comfortable work, not just barely enough, then it's enough.
Giving somebody who never held a sharp knife in their life a knife that is so sharp it will cut their fingers without them feeling it (or even close to that sharp) is like telling somebody to run a coding agent on their system and not in a VM. Things can get bad really fast.
Most people (at least in central Poland where I come from) used semi blunt knives* for everything. Some would have a household knife sharpener or maybe even low quality sharpening steel like the ones you get in a knives set. Maybe they or their grandma had a butcher in the family. They will have nice sharp knives that can cut tomatoes without crushing them.
But with a knife that is sufficiently thin, a throwaway leather belt, a little skill and an hour or more of time, you can get a mirror-like polished blade that is so sharp you can amputate limbs in seconds. Just need to go through the joint at a correct angle.
That's how our grandfathers shaved.
* just realized I was typing plural for knives wrong - with an 'f'
"During the prep I said, "wow I wonder how sharp the knife"" Is there something missing in the story? (drugs, coercion, self harm ideas, anything) I have had my fair share of avoidable cuts, but none of them included looking at the edge before happening.
I didn't look at the edge, I was just thinking of that idea while slicing some vegetables and coincidentally not paying attention at the same time.
The way you asked that question is wholly inappropriate for a public forum and also rude.
Irony deficiency
What, last night?
haha :D Sorry,English is not my native language! What I meant was: "During the last years until today"
Is this sentence better?
In your first comment, replace “until today” with “since then” and you’re good!
“Until today” is one of those English phrases that is particularly unfair on non-native speakers. You know “until” and you know “today” and so it’s completely natural to combine them in the way you did.
But as ever, English is dumb and annoying and hard work, all at the same time.
Liver as well, but I have no idea if that's the same underlying phenomenon.
Not a single mention of the work on limb regeneration by Professor Michael Levin's lab at Tufts?
https://as.tufts.edu/biology/tufts-center-regenerative-and-d...
He builds (albeit nothing really meaningful) on top of the work of Robert O. Becker, I highly suggest you read his book "The Body Electric".
Was waiting for your comment.
In a study they figured out that organs seem to have an electrical potential range as a signature/command for stem cells for which organ to build and where.
In a frog they were able to grow legit eyes in the gut just by artificialy inducing a certain voltage in that area. No need for any cell transplantations: the voltage really seems to be the only signal needed.
This might also be how it might be done in the future in humans: block scar tissue then induce voltage with the signature of the organ you wish to regrow.
https://pubmed.ncbi.nlm.nih.gov/22159581/
The trick is to make regeneration fast enough to heal the wound without making fast enough to cause cancer. Maybe even supported by provisional fibrosis.
Does that mean zebra fish with their ability to regrow the retina get cancer at a higher rate?
90 day life cycle. Rare for them to live over a year in the wild.
Whoa, sounds like your recommending some sort of healing mechanism like those human animals have
It's just hidden by a feature flag.
(Probably for a good reason)
tbh I think it's probably just commented out (and is about as likely to still work as any other commented-out code)
Methyllated out....
Evolution is so smart.
Monte Carlo smart, not optimized compiler smart.
Like the way slime molds solve mazes: explore every possible path in parallel, and push growth in all areas with greater nutrient gradients. Not by sensing any gestalt clues, like symmetries in the maze design.
Astoundingly stupidly smart.
Wasn't this proven many years ago by a random guy who used a "extra-cellular matrix" of stem cells to regrow his severed finger, nail and all?
Found it: http://news.bbc.co.uk/2/hi/7354458.stm
No, the end of your finger just can grow back. https://www.npr.org/sections/health-shots/2013/06/10/1903854...
Dude's brother had him throw his product on the finger as it did so, definitely an astute marketing trick. https://www.theguardian.com/science/2008/may/01/finger.claim
I recall reading a similar story with powdered lizard. Also just a fingertip.
"I don't know how it works, so it must be fake news."
To be fair, the person being skeptical is just a surgeon, this is not a peer-reviewed study or anything actually scientific.
Your NPR link even shows that scientists realize there are still unknowns:
> "We think that nail stem cells may a have a special function to induce the whole regeneration process, including nerve attraction and growth of the bone," Ito say.
A cursory search seems to say that typical regrowth of a nail takes 4-6 months, but Spievak claimed his only took 4 weeks.
Can we say definitively that his "pixie dust" had nothing to do with it? I don't think so. Can we say it did have something to do with it? Also unknown... but the answer right now IMO certainly isn't a scientific "no."
If it worked on humans 13 years ago, then by now it would have worked on a human who was not sibling to the inventor, in a way not essentially identical to life without it.
I'm hoping that this can be applied to routine genital mutilation in humans that are often done near birth and without consent.
Perhaps humans can one day regrow their teeth for better food ingestion when elderly and cognitive function.
[dead]
Maybe that's what Jesus used on the people that he healed
In the whole Christian tradition, God/Jesus generally does not go for organ or limb regeneration. Two counter examples are a healed ear in Luke (but this may well have been resumption of hearing? details are a little light), and then a single Spanish example in the 1600s.
For His own mysterious reasons, He simply doesn’t go in for that stuff, however much intercessionary prayer ends up in His inbox.
not an amputee, but he did heal a man with a withered or malformed hand in Matthew 12. he also healed plenty of cripples, so I don’t think it’s a stretch to think that some or many of them were missing limbs.
Why does god hate amputees?
Difficult to pray without 2 hands.
Buddhist golf clap to you, with one hand.
Judge not, lest ye be denied CRISPR.
> Maybe that's what Jesus used on the people that he healed
I think this is what all healers used. They were all way ahead of their time and clearly misunderstood.
Jesus, if he existed, didn't actually heal anyone or perform any miracles. That's mythology, not reality.
How do you know?
I think to claim that 2000 years ago there was one person who performed miracles and/or healed people that nobody else could, with no actual evidence it was done and nobody else has been able to do it since, you need a better response to someone questioning it than “oh were you there? prove it didn’t happen.”
No I don't because I'm not claiming that I know that it happened
What can be asserted without evidence can be dismissed without evidence. There was no Jesus who performed miracles of healing
even the Jews of the time that did not believe or follow Jesus wrote that he performed signs. They claimed it was sorcery.
in Folio 43a of Tractate Sanhedrin of the Babylonian Talmud as follows:
‘It is taught: On the eve of Passover they hung Yeshu and the crier went forth for forty days beforehand declaring that "[Yeshu] is going to be stoned for practicing witchcraft, for enticing and leading Israel astray.”’
The relevant portions of the Bible record that the Jews of the Sanhedrin acknowledged the signs and miracles but said it was by the power of Satan that he did these things.
They also have countless records proving hundreds of thousands of women were witches, with ironclad proofs such as “if we stab them they scream so they must be witches, off to the pire” or “throw them bound in the water, if they float it means they’re evil because water (baptism) rejects them so they’re witches -> burn.”
> What can be asserted without evidence can be dismissed without evidence
What’s your evidence for this claim?
Logic. Prove I didn’t eat a peanut just now; good luck.
He's not unique though. Quite a few people are on record for performing miracles in front of large audiences. Seemed like it was all the rage around this time period.
Vespasian apparently healed blind people in Alexandria. Apollonius of Tyana had a very colourful life performing all kinds of magic. Honi the Circle Maker was bringing the rain over in Judea.
Must've been something in the water other than lead!
>How do you know?
a 4 word summary of the entire works of every religion in the world, ever -- the original Pascal's Wager flavored FOMO social networking maneuver.
Because I'm a grownup who knows the difference between reality and make-believe.
I take from this that you don't, otherwise you would explain it
You're the one who believes magic is real, it's up to you to explain it. Extraordinary claims and such.
This is ironic. They didn’t say they believe. You offered your belief that you know something that happened long ago (extraordinary claim), and they are naturally curious how you could know that. If you’re a time traveler or whatever we’d be quite interested to hear more.
Not everyone whose unfalsifiable beliefs differ from yours lacks maturity. In fact, some of them are mature enough to not resort to insults.
Signed, 50 years an atheist.
Because I was there?