If you really want to learn about this stuff, Robert Weinberg's The Biology of Cancer is where to start. It introduces concepts starting where a high school student could understand and carefully walks through the history of our development of knowledge until, by the end, the pithy chapters are helping novel concepts for real science flower in your brain all on their own. It's the best book of biological science I have ever read. 10/10, will read again.
We do do palliative surgeries if warranted but the intent there is not to cure, but to relieve some symptoms and transiently improve quality of life.
Please direct any specific questions you have about your sisters case directly to her doctors
Thanks for the rec, I'm buying it just so I can explore their world a little bit.
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almost like... cancer itself
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What is it printed on??
https://archive.org/details/the-biology-of-cancer-3rd-editio...
> Does SV40 cause cancer?
Yes, in a range of animal models at least.
SV40 can 'immortalise' cells, turning off regulatory functions which prevent uncontrolled division, which is an important part of carcinogenesis. This has been shown to contribute to cancer in experimental systems.
> Did and does SV40 inadvertendly inside the Polio Vaccine in the late 1950ies and 60ies cause cancer?
The evidence suggests not significantly, although it's impossible to rule out for some unlucky individuals.
The SV40-exposed cohorts rates of cancers don't differ that greatly from unexposed groups, so we can say with certainty that the rate is much less in humans than seen in laboratory systems. There were suggestions of differences for some cancers, but these are heterogeneous and often confounded, and the general consensus now seems to be the effect was small if not zero. I don't think there's a definitive answer on why - possibly the exposure was sufficiently low or the virus was not effective at infecting humans to significantly affect the carcinogenic processes.
> Does the Pfizer proces 2 SV40 promotor in the Covid Vaccine cause cancer?
Certainly not by the mechanism intact SV40 causes cancer.
That depends on the production of particular SV40 proteins which interfere with cell functions, which aren't present in that promoter.
> Does DNA contamination in general cause cancer?
In general, no.
Cells are constantly exposed to both native and foreign DNA fragments, and have plenty of mechanisms for dealing with them. Even if fragments were somehow incorporated and expressed, most are not inherently carcinogenic.
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Also, although the article is mostly true, there are some inaccuracies:
>> Neurons and cardiac muscle cells don't reproduce after childhood
There is some evidence showing a slow cell turnover in cardiac muscle, estimated around ~1% per year in young adults, falling toward ~0.5% in older people. Most neurons don't regenerate, but there an evidence that some parts of the adult brain (such as hippocampus) still produce new neurons, although the number is very low.
Liver regeneration is not perfect either: https://www.youtube.com/watch?v=rOv7Sr3X-eo .
Complications with healing are pretty brutal. Necrosis, amputation, infection are all common without the built-in cascade we have.
I received a cut-down liver from the donor; I got the bigger lobe, a child recipient got the other lobe.
Within a few months of transplant, the new liver had regrown, but (probably because of the transplant orientation) rather than growing across to the left, it grew down the side of my body.
It's all good and functions fine, it's just that now my right-side of my body isn't as 'saggy' as my left because of the area it grew in to.
It's an amazing organ, and it truly sucks when you don't have a well-functioning one.
I recently learned about this (not sure if it was a YouTube video or an article): apparently, it's not that we become infertile long before we die, it's that we live long past our fertility ends. And the reason for that is really simple: old people have accumulated a lot of knowledge that is valuable to teach to younger generations. The alternative is not to be fertile longer, but to die younger.
Presumably, menopause only occurs in species that learn and teach, and are able to accumulate so much knowledge that it becomes useful to keep experienced individuals alive longer so they can continue to teach.
To the author: thank you, you made my day. It had been a very, very long time since I last read an article on the Internet that felt written by a human being - with humor, some poetry, and science.
This is a very outdated view. Neuroscience has shown that neurogenesis continues throughout the entire life span of humans, albeit at a much slower rate. You might have a hard time recovering from a serious brain injury or stroke but losing a few brain cells won’t change a thing.
Immune attack of the pancreas is usually a disease of youth. Type 2 diabetes which is overwhelmingly the diabetes associated with aging is not an autoimmune disease.
The Greeks chose liver because it symbolized the defiance Prometheus had against gods.
Liver regeneration has been known since the ancient times: in Greek mythology an eagle was eating the liver of Prometheus every day for thousands of years after Zeus punished him for donating the fire to humans but he survived to be saved by Hercules.
So, monkeys and apes (besides one species of chimps) don't get menopause, elephants don't get menopause, lions don't get menopause. If your prediction is, social animal => menopause, it's wrong 99% of the time.
This isn't entirely true. I have notable damage to one side and in the recovery process there was a significant increase in the visibility of the surface veins on that side. It's still clearly there years later. Existing vessels can grow larger when repair processes kick in.
https://www.science.org/content/blog-post/no-heart-cancer-th...
Apparently, physical health isn’t something you’re going to talk about with investors and users, even though it affects everyone. Before AI, this field was too specialized and there were very few founders willing to work in it.
With the mRNA based vaccines during the COVID pandemics, there has been some reports of resistance and loss of efficiency of the vaccines after vaccinating >3-4 times. It was said the body don't see the actual mRNA pieces but starts to attack the carrier-molecules. Later on, I've seen some paper I don't remember, but it stated the antibodies stopped reacting to that mRNA at all (got used to). There was also a story of a man who vaccined more than 400x with the mRNA vaccines (stupid honk!).
So, may be this is a way for Transplantation? Take the surface molecules of donor, put them on xxx and admister them next months and years while constantly reducing the suppression.
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This is always a problem when one tries to view biology through an engineering lens. The functions we see today emerged well after the genes themselves started on the path that allowed them to support these specific functions in us. Nor are the genes restricted to exactly identical functions even when their sequence is identical. The context of each cell matters.
Rather than beginning from external function and going down to find energy, replication and cancer/escape from multicellularity as factors affecting these organ’s behavior, it’s a lot better to go cell up, where metabolism, DNA replication, waste clearance, and cell to cell communication and cell-microenvironment sensing are all constantly having to be balanced.
The functions we see from ensembles of cells are composed of these cell level behaviors multiplexing.
And when we look at the eukaryotic cell, we don’t just see linear DNA. We also see mitochondria. Our mitochondria reproduce and proliferate in all cells, depending on energy requirements. The process also produces a lot of reactive oxygen species which need to be kept tamped down to prevent damage.
And the mitochondrial endosymbiotic event also potentially explains why we have linear DNA in a separate compartment. From first eukaryotic common ancestor (FECA) to the last eukaryotic common ancestor (LECA), you had two genomes inside one cell, and by the time we got to LECA a bunch of DNA from the alphaproteobacter that became mitochondria migrated to the core genome, leaving the mitochondrial genome to remain circular.
The exact time and reason for linearization of DNA is (as yet) lost to deep time. But we can see a path from two circular genomes to one linear one circular and construct a fairly believable hypothesis to why you got linearization: as cell type increased, you needed more transcript copies, and access to different transcripts at different times at different rates. A linear genome is much better able to accommodate these requirements. And this has resulted in prokaryotes also partially or fully linearizing some of their genomic material when the need arises (Cyanobacteria, the first autotrophs, have some strains with linear ends, and Lyme disease and streptococcus also break from full circularity).
This linearization is also critical for mitosis and meiosis.
As far as the exact causal chain, we are, at the moment, groping in the blind, since the FECA->LECA transition occurred some 2 billion years ago, and we don’t have candidate fossils. They are reconstructed from genomic puzzle pieces, which is why we have these holes.
In that transition timetable, it is possible commitments were made that shape everything we see today.
Beyond doubt, those commitments had to thread everything a single cell has to thread.
And then came multicellularity, which had its own tradeoffs.
Teleology doesn’t help because none of these early commitments were being made with the specifics of our current lifestyle in mind, or even that complex beings like us could exist.
Evolution is a blind watchmaker. Ignore that and you’ll end up with nice sounding ideas that may not quite fit what we see.
And so, from the very same premise, evolution don’t necessarily need individuals that are long standing, even less in environment which are themselves very unstable. As long as species continues to exists, evolution made its job. In more stable environments, long life span is causing less pressure on chance for the species to remain viable. A large motile animal in ocean don’t have to face that much significant changes in environment compared to their out-of-water counterparts. Of course the environment alone don’t explain everything in term of most efficient strategy, size matter, mobility mode matters, how much of such an environment exist and how large the population can grows before facing a demographic cap, just to cite the first that comes to mind.
I’m not a biologist, at all, and even a random layman as myself can comes with these obvious ideas.
That said, I also have all kind of blind spots, no doubt about it, and I didn’t even write a very nice to read issue on the topic unlike the author of TFA.
https://en.wikipedia.org/wiki/List_of_longest-living_organis...
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We can expect evolution to do the right thing for the genes. Not for us.
I greatly resent having to be a biological organism and subject to all the poor engineering and design decisions that entails.
And then this:
Brains. After you reach adulthood, neurons don’t divide. If some of your neurons die—which happens every day—then they’re gone. If you get a brain injury, the other neurons will try to “learn around” the injury, but the neurons themselves are never replaced.
Those of us with who get injuries that are life threatening, our genetics have engineered us to be culled from the gene pool. It's to protect the gene pool from other genes.
It's like if car makers made a car with square wheels but every time the car got into an accident it would repair itself so we would keep driving it. Evolution instead blows up the car as soon as it gets into a accident, so then only round wheeled cars remain.
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From Wikipedia
> "In developing nations, however, 70–90% of vitamin A is obtained from provitamin A carotenoids in plant foods"
and
> "Whereas retinoic acid can be produced from excentric cleavage of β-carotene in humans (31), it is generally considered a minor contributor to circulating concentrations, at least in normal, healthy persons"
Google tells me that "Two pathways have been suggested for the conversion of carotenoids to vitamin A in mammals, central cleavage and excentric cleavage".
Carotene conversion cannot both be "a minor contributor" to body levels of Vitamin A and also the main way billions of people get Vitamin A. So my guess is the Wikipedia page has mistakenly taken 'excentric cleavage' to be the only conversion method. Still, ignoring carotenes entirely, the referenced paper also says:
> "observational studies suggest that more than 75% of people may be routinely ingesting more than the recommended dietary allowance (RDA) for vitamin A"
Carotenoids are used as a natural food colouring, beta-carotene is E160a, e.g. I've seen it in Red Leicester cheese, yellow custard powder, red jelly, in glace cherries. American law requires vitamin A fortification in reduced-fat dairy. Companies optionally fortify it in things like wheat flour, or breakfast cereal. Retinoids are in beauty and moisturising skin creams and sun tan lotions, and sometimes used as extreme acne medication.
Things that have been promoted for "good health" for decades, such that someone who wants to avoid it needs to deliberately choose an awkward diet of non-colourful foods like potato, rice, onion, parsnip, coconut, apple, pear, cucumber, zucchini, black beans, white beans, lean meats or carefully chosen meat fats, breads made from un-fortified flour, avoiding many restaurant, take-away, or processed foods and "eat the rainbow" variety of fruit and veg.
Grant Genereux has proposed that overflowing the liver's ability to store and process Vitamin A / retinoids leads to them circulating in the blood, that they can enter cells bypassing the normal methods, can cause damage which makes cells denature and burst, which triggers an immune system response to try and find an attacker, which gets misdiagnosed as the immune system causing the damage. And has proposed this as a mechanism which explains some of the 25 - 50 million Americans having unexplained auto-immune diseases.
Proposing that retinoic acid builds up inside body cells over years and decades even whan taken ordinary 'safe' levels, not enough to trigger hypervitaminosis A or acute symptoms but chronically accumulating until the body has so much of it stored that cell damages releases retinoids into the bloodstream which enter nearby cells, denature some of them, releasing their stored retinoids, causing a domino effect which we know as an auto-immune flare-up. And that it's a matter of luck where the concentration is higher whether that makes a skin rash or a kidney or joint or thyroid inflammation, or just generally high "inflammation".
It's an interesting hypothesis with a lot of specific testable claims and specific proposed mechanisms, mixed with quite a lot of conspiracy theorising and less-testable claims.
- the recommended daily vitamin C is 90mcg for men and 75 for women, the upper limit is 2000mcg. That's a safety margin of 22x, and exceeding the upper limit may cause diarrhoea and gastrointestinal distress.
- the recommended vitamin A is 900mcg for men and 700 for women, and the upper limit is 3000mcg. That's a safety margin of 3.3x, and even that upper limit has "some evidence that this much preformed vitamin A might increase the risk of bone loss, hip fracture, or some birth defects".
- "Sometimes people take cod liver oil for vitamin D but may not be aware it is also very high in vitamin A, beyond the RDA at 192%"
That is, even without any alternative views on it, it's much easier to go above the safe levels, easier to do accidentally, and the risks are more serious.
As for measuring: there might be spillover of retinyl esters (storage form in the liver) into serum, but that's nothing that's commonly measured. (Serum retinol levels do not correlate with liver levels AT ALL.)
It can also raise liver enzyme values and change lipid values.
(I recently finished a round of Accutane, basically high dose vitamin A)
ebook $100.64 here: https://www.vitalsource.com/products/the-biology-of-cancer-r...
https://www.amazon.ca/Hyperart-Thomasson-Akasegawa-Genpei/dp...
I meant this Sci Fi book
>Certainly not by the mechanism intact SV40 causes cancer.
There are researchers that claim this makes it an even more virile cancer causing agent.
A fantastic closing if the goal is to make people not answer your questions. I don't know if you're friendly enough to explain why you made your comment so hostile. Probably not.
"friendly enough to address these issues".
He is not part of some research group who is researching this type of topic. You assume he is a bad faith actor with your "probably not".
Either accept the status quo / research on this topic, or do the research yourself but don't take some potential conspiricy shit to hn by cheap shooting someone else with your 'probably not'.
And if you really struggle with this type of things, get help.
Admittedly yes. However, this does not make me ignorant.
The type of questions I wass asking should have been an indication that I'm interested and researching.
All basal metazoan branches (ctenophora, porifera, placozoa, cnidaria) have species that are capable of whole body regeneration, so this trait was likely lost on the bilaterian branch (which includes chordates like ourselves). If anything, there are evolutionary pressures to loose this trait.
I have no idea of the truth of this, but there are anecdotes of farmers losing limbs and walking back to their tractors, driving back to the farm, then driving themselves to hospital, and the like.
As anatomy gets more complex, the process of getting it from "arbitrary heavily damaged state" to "functioning state" gets more complex too. And mammals are a bit more anatomically complex than placozoa.
If your entire body is a hollow sphere 4 cells thick, "repairing arbitrary damage" is very simple and natural. When you have bones, blood vessels, nerves, muscles and tendons, all wrapped in skin - all of which have to be restored correctly for a lost limb to function well? The gap between "just plug the holes" and "restore the function" grows, and the complexity of implementing usable regeneration goes up massively.
Humans can repair most of simple tissue-level damage well enough. The complexity equivalent of placozoan regeneration is in place. Rebuilding complex anatomy is what's often unimplemented. Seems like that is the part that requires some novel adaptations rather than simply not deactivating the mechanisms that are already there.
Maybe, but isnt this basically tautological? "You didnt evolve this way because of how evolution works". The more interesting question is why did certain parts evolve the way they did, and can we harness the knowledge?
people have a hard time grasping this concept for some reason.
my favorite example to illustrate this is the trait of being poisonous. if evolution cared about species and then every single one would be poisonous and all predators would have to hyper specialize in prey (arms race between a particular poison and its resistance). it's precisely because it's so difficult to elicit a benefit from this strategy for the lineage that it's so rare. almost always a mutation in coloration has to happen to set the lineage apart from the others first. and then the lineage has to survive the disadvantage long enough.
> acts on the molecular, cellular
https://en.wikipedia.org/wiki/Structural_inheritance
basically, the genes do not generally contain blueprints but rather processes utilizing existing cellular machinery. a "mutation" can occur in a machine which will allow a propagating difference.
and there is nothing special about populations. it's merely the only way to observe most changes. gene frequencies in gene pools.
The liver's great ability to regenerate largely boils down to how homogenous and simple the liver actually is. It's structured more like a battery pack, where you have individual cells that are largely functionally identical to each other that perform the bulk of the work, and they happen to be connected together. If an individual cell fails, (for the most part) all you need to do is merely regrow a new one, and it's orientation matters little (relatively speaking as compared to other organs) so long as it's connected to the rest of the battery pack (organ).
Contrast that to something like a kidney, which has complex orientation that is formed via growth, and which has a high degree of different types of cells where replacing a part isn't as simple as merely regrowing the part which failed, but also about that growth happening in precisely the right location. So instead of it being like having to replace a failed cell in a battery pack, it's like replacing a wheel to a car. Attaching it anywhere (like the windshield for example) won't necessarily fix the issue, it needs to be connected to the axle...
Presumably this didn't happen because are ancestors were dumb, but rather because the ability to process slightly spoiled food is a significant advantage in an environment where fresh food is sometimes scarce?
Survival in the wild is harsh, yo. Try for every scrap of food.
That's why so many professional athletes take MSM (Methylsulfonylmethane). Their bodies would not be able to recover as quickly without the extra sulfur.
Ideally we could have a switch, low inflammatory reactions when good, high inflammatory reactions on injuries.
Some people also have rare diseases where they don’t have clotting factors so require a transfusion of clotting factors before surgery for optimal wound healing.
Megakaryocytes are primarily bone marrow cells.
Almost like Apple with component serialisation.
Even if we assume your body has a foolproof is_same_species() test, your neighbors' cells may:
1. Be healthy, but have the wrong priorities or behavior, so that they start doing the wrong tasks or sending the wrong messages in the wrong places. [0]
2. Be healthy, but they're just a creepy flesh-mask a parasite has constructed around itself.
3. Be individually hijacked by viruses, and your body won't have the same baseline information to tell that they've deviated from your neighbor's standard.
4. They may be fully human, but gone feral into a transmissible tumor [1].
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[0] This is actually a risk from pregnancy, as overambitious fetal cells leak into the mother.
[1] https://en.wikipedia.org/wiki/Clonally_transmissible_cancer
As others have explained, foreign cells usually meant trouble, so fighting them by default was a good choice. And there was no pressure to allow transplants specifically, because they didn't exist.
Also, (I think) you usually need a transplant later in life, after reproduction, so too late for evolution to affect it. So even if we had transplants for millions of years, it might not have made much difference either.
The reason I needed a kidney transplant is because of an auto disease called IgA Nephropathy where the IgA antibody has a small defect that causes the rest of the immune system to attack it and the whole mess clogs up the kidney filters over time.
1. Bacteria
2. Parasites
3. Cancer
In all these cases cells that are "other than your own" are in your system and need to be eliminated, in the case of cancer it's your own cells but with significant mutations, as far as I can tell there is always an immune response although in some cases it is actually counter productive.
The only useful signal is "This wasn't here yesterday". Your body generates B cells with a little sensor that has it's own special systems to have especially randomized sensor activity. Your body is generating random binding sites because there's no rules for what a hostile protein would look like.
Then it prunes these B cells by showing them a bunch of proteins your body is capable of producing, and killing any cell that signals for proteins your body normally has. This leaves you with a bunch of B cells that have random sensors tuned to only trigger for things that weren't in your body yesterday.
This is great, because it's a proactive measure against evolution. It's the core innovation of the adaptive immune system, and a massive advancement in biological self defense.
https://en.wikipedia.org/wiki/Germinal_center
Cells from someone else will have some different markers and proteins than found in your body. Human genetics are 99% the same yes, but there is massive diversity in the remainder.
Note that this constraint is not biological in nature! Any general purpose "programming" environment cannot differentiate between "Hostile" and "Benign" by function or structure alone! The body, like many smart cybersecurity groups, made an allowlist. Though the way that allowlist is made is fascinating
When we noticed the signs and went into the ER a few of the (younger) doctors thought it was Type 2, while the attending knew it was just late onset Type 1.
For example in Persian poetry the word liver is found pretty much everywhere you would expect to see the word heart.
"You are my liver" is a nice/romantic thing to say to this day.
It could have been because the liver was regenerative and they were using the titan with the regenerating liver as another reference to humanity, or it could have been as someone pointed out because predators like to eat the liver first, or it could have been that you can take damage to the liver and live for hours afterwards in agony whereas the same amount of damage to the heart or lungs is apt to cause death to come much quicker.
Perhaps there are undiscovered variants out there were the eagle or a serpent or some other animal attacks his genitals, or his eyes.
But at any rate the Eagle ate his liver, it means nothing in particular, and at the same time it means every particular interpretation we can place on it.
So by destroying Prometheus' liver, Zeus attempted to destroy his human emotions, including his pride and defiance against gods.
Conversely human offspring is especially weak and incapable and susceptible to harm, and experiences a lot of threat even within the same species.
Not sure where that are of whale and chimps fit into that - flukes can also happen I guess.
Most species make a baby (or babies), raise them to maturity before having another. Even a low chance of successfully raising another child is advantageous over no chance at all from turning off the baby maker. Humans, however, have children of a range of ages, making more before the first is finished. Having another inherently takes away from the ones that already exist. Having another that probably won't make it can be an evolutionary negative.
And humans have a much longer portion of their life spent on each offspring. This increases the chance of death before completion and thus makes more evolutionary pressure towards not putting effort into futile things.
Note that this works even if she is alone and doesn't help with the grandkids.
I watched a Ted talk where the speaker suggested our large brains with their high energy consumption would not have been possible were it not for cooking.
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(If we are talking about hunter gatherers, not poor exploited peasants)
In any case, what would you expect from such a platform? That would help with recomendations.
I think the best place to discuss most things nowadays is the real world, but it takes time to build connections in the real world. HN is still a place of real productive discussions but not without a lot of moderation and even so it's still barely functional.
Basically every flavor compound in an herb or spice we eat is a poison directed at insects, microbes, or other creatures. (much less every medicinal or psychoactive compound found in nature)
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This is common in evolutionary algorithms anyway so it's notable we don't see it in nature, at least not in the form of extended lifespan perhaps measured by average lifetime heart beats. It's easy to imagine a world where nature might want to keep the alpha lion around longer than the others so it can have more offspring, for example.
There is, if there were no advantage a whole lot more species would die immediately after reproduction like the octopus.
Many simpler organisms are vaguely immortal.
>It's easy to imagine a world where nature might want to keep the alpha lion around longer than the others so it can have more offspring, for example.
The utility of genetic diversity puts a lot of pressure against this.
I didn't just meant extending lifespan, I meant extending the time an individual is fertile.
> The utility of genetic diversity puts a lot of pressure against this.
High levels of elitist selection lowers diversity and can have a negative impact on a population's adaptive ability, but there is a sweet spot to diversity. Maximally diverse is just noise after all.
A small amount of elitism is generally what you would expect to be selected for, and we certainly see this other forms in most creatures, but never in the form of extended life span. That makes me suspect there's probably something fundamentally difficult about extending an organism's lifespan given our biological architecture and that's why evolution has favoured other forms of elitist selection.
That's it. That's the entire thing. Plus some nuance about things that self-replicate faster than other things...
It occurs at all levels. Amyloid protein in Alzheimer's patients is self-replicating. So are cells. So are individual parts of cells. Sometimes things replicate by being parts of a larger thing that replicates, sometimes they don't. It's all one big chaotic tangled mess with no particular purpose or design. Human cells evolve, so do humans, so do human societies. So do rocks.
But it's also pretty reductive to say it's the entire thing. You'd be hard pressed to describe the history of life on earth using only those three concepts. You could do it, but it would be a bit like describing the workings of a human cell exclusively using quantum field theory.
There are many emergent concepts, the understanding of which brings a lot more explanatory power. Things like selective pressure and evolvability. Our understanding of evolutionary biology and evolution in general indeed continues to evolve nearly 2 centuries after On the Origin of Species.
One of the most interesting things to me is that the process of evolution itself evolves. Variation, replication and selection evolve over time. Evolution seems to accelerate. Evolution can even create entirely new substrates for itself on top of the old ones. If you look at all the traits that distinguish humans from our closest relatives, the brain sizes, the slow maturation of offspring, our vocal chords, complex language, etc, there's a single thread running through all of it, namely an entirely new evolutionary substrate: culture. Once culture appeared, evolution accelerated massively. And cultural evolution itself seems to accelerate. It took several hundreds of thousands of years to get to the agricultural revolution, but then it only took several thousand years to reach the industrial revolution/enlightenment. From there it took centuries to invent the computer, about half a century for the internet and now society changes dramatically within a single decade, some might even argue a single year. In certain specific cases, we can even do evolution in the span of hours or minutes (seconds?) now, with genetic algorithms and the like.
And yes, biological evolution, cultural evolution and genetic algorithms all operate via variation, selection and replication, but it should be pretty clear by now how important all the little details and emergent phenomena are for understanding the differences between them.
And amyloid protein doesn't self-replicate. An instance of the misfolded form causes other folded proteins of the same type to transition to the misfolded form. It's a form of catalysis, not self-replication.
Loss of neurons isn't disastrous as long as it's not too many. Babies are born with several times more neurons than children have, and spend a few months letting all the useless ones die. Apparently it's better to start with a random tangle and prune it to shape (like cutting a box hedge) than to make a hedge grow in a box shape to begin with.
And IIRC brains can grow more neurons under some circumstances (certain drugs?) - they just normally don't.
https://www.sciencedirect.com/science/article/pii/S193459092...
Evolution does not care about creating perfect bodies, that's not how it works. Aging and death are superpowers of an unique arrangement of matter, not bugs.
We know diabetes and other issues come from changes humans introduced in our diets, not faults in the evolutionary process.
The text draws from a weird mixture of religious influence (it's not explicit) that lowkey estabilished things should be perfectly designed (in science, mentioning "design" is an issue; fine but aged badly in science communication). It's just not the correct framing to be educational about how our bodies work, and sets up wrong expectations about what we know of nature.
Now sure, others say that retinoids play a role here, but "we know" sounds a bit far fetched.
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It may seem odd to demote correctness in that way, but it doesn't mean we value incorrectness. Correctness is good, just not at the top of the hierarchy. Curiosity (specifically, intellectual curiosity) is what we're optimizing for: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor....
We value the freedom to meander curiously. Some paths turn out to be wrong [1], but that is how new things are learned, and it's a good way to spend time. People are allowed to be wrong on HN as part of figuring out what's true [2]. Truth is crucial, but one ought not to squeeze the throat of speculation so tightly that wrong things aren't allowed to be spoken, or fun to be had.
[1] not saying the OP is right or wrong - I have no idea - but the article looks like the fun kind of meandering that has a place here.
Edit: https://www.etymonline.com/search?q=meander - "from Greek Maiandros, name of a river in Caria noted for its winding course". Is there a better website than etymonline?
[2] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
> "Dietary vitamin A is obtained from preformed vitamin A (ie, retinyl esters from animal foods, fortified foods, and pharmaceutical supplements) as well as from provitamin A carotenoids from plant sources. Preformed vitamin A is efficiently absorbed and utilized by humans at absorption rates of 70–90%. Up to 75% of dietary vitamin A in Europe, the United States, and other industrialized nations is preformed vitamin A (1, 2), which is largely derived from multivitamins, fish liver oil, and the fortification of foods such as milk, butter, margarine, breakfast cereals, and some snack foods. In developing nations, however, 70–90% of vitamin A is obtained from provitamin A carotenoids in plant foods. These are absorbed much less efficiently, at rates of 20–50%, depending on each person’s vitamin A status and other dietary and nondietary factors (3, 4). The cleavage of provitamin A carotenoids to retinal is a highly regulated step, and vitamin A toxicity from provitamin A sources is largely impossible. In contrast, absorption and hepatic storage of preformed vitamin A occur very efficiently until a pathologic condition develops."
If you take "the cleavage of provitamin A carotenoids" and Ctrl+F for 'cleavage' or 'carotene' in that paper, the only other mentions are this:
> "An acute elevation of retinoids other than retinyl esters—eg, retinoic acid—occurs after the ingestion of a large amount of vitamin A, possibly because the intestinal absorptive capacity is overwhelmed, which leads to the oxidation of retinol to retinoic acid by the intestinal enterocytes (30) and to the rapid formation of retinoic acid from retinol in certain cells (5). Whereas retinoic acid can be produced from excentric cleavage of β-carotene in humans (31), it is generally considered a minor contributor to circulating concentrations, at least in normal, healthy persons."
That is, they only seem to be talking about excentric cleavage and not central cleavage. My limited understanding is that beta-carotene is roughly two retinoic acid molecules chained together, and cleaving them in half is what makes two retinoic acid molecules, and that non-central-cleaving would be different. See skeletal formula on right for these two pages:
https://en.wikipedia.org/wiki/%CE%92-Carotene
https://en.wikipedia.org/wiki/Retinoic_acid
(You can also wonder if beta carotene can produce 90% of circulating vitamin A in developing countries, whether getting lots of beta carotene in developed countries can raise the base level in the body, which then leads to easier overdose from preformed vitamin A)
I mean... think of Deadpool's baby hands. Jesus.
And that "eating glass" comment is related to how I know. I boiled a wild "edible" (skunkweed leaves) in 3 changes of water; what I should have done is either dry it completely or (better) treat it with lye. Bad memory mistake. Yeah: eating glass shards.
2024: 11,458 total (604 from living donors)
Once you start looking at even more factors, you start reinventing a regular DNA-matching test.
[0] The "Birthday Paradox" makes the odds of confusion even higher with more siblings.
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e.g. microberto on X, nutrition detective on YT
Just went and checked, evidently he never said anything about it.
old American translation of Galen and Hippocrates for anyone interested, as it can be difficult to find otherwise
https://oll.libertyfund.org/titles/coxe-the-writings-of-hipp...
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Possibly because it's filled with strong acid.
We are certainly much healthier, with the little trinkets we keep in our houses.
The real point here, is a lot of people today don't realize how supported they are, with medicine and the trappings of modern life. The simple things I've listed are quite literally a wonder, but to the modern human, often it's not even considered a big deal.
Even in a rural remote areas of Canada or the US, you can just get in your vehicle, drive for half an hour, and then suddenly be surrounded by tens of thousands of products to make you healthier. A city dweller can walk for five minutes, and have the same.
If you made it past age 5 as a hunter-gatherer you’d likely live to 50-60 years of age.
No doubt. But I like to spend time in remote wilderness, so I do know what I have and do not have there. I definitely feel healthier if I am outside more often and can take care of various injuries myself, but if I would really need one, I surely would call for a modern medical helicopter and not go find some plants.
If the predator is not breathing down your neck? You are watchful but ignore it.
Similarly, our ancestors and ourselves? We are social animals. We live in a pack. We share defense with our tribe. You and your neighbour will stand back to back, to fight off barbarians. Meanwhile, in parallel, we need to defend ourselves from members of our tribe. The very person who fights back to back with you, to save your community, may be your tribal competitor. Whether for dominance or breeding, we fight amongst ourselves. We know there is risk of our neighbour, our fellow community member attacking and killing us, meanwhile? We lay our head down and sleep.
We're designed to take low probability threats, and cast them off, and nothing is more low-probability than 'it will happen in the mysterious future'.
Global warming is as 'far off' thing. You may say "But this and this is happening!", and I agree! But I still live in my house, I still have grass and trees, I still have food, and so for most people "far off in the mysterious future" is a valid response.
If you can't see the enemy before you, it is easy to shrug away. If you cannot see the threat as impending, it is easy to ignore.
It's in our very nature. It's a requirement to sleep soundly at night.
At least, this is my take on 'far off' threats.
But I thought more in terms of less is more. Introducing artificial temporary scarcity to foster creativity instead of relying on sheer volume of information to increase the chances for high quality interactions, which also increases the absolute volume of low quality noise.
Also maybe after quarantine is over your thread could be accessible to everyone else so others could join later, as long as the group agrees to open up the discussion.