Escapee pregnancy test frogs colonised Wales for 50 years (2019)
bbc.com
bbc.com
- What decision-making process led to the idea of injecting human urine into a frog in the first place?
- How did the frogs escape? What kind of living and handling conditions are we talking about here?
- Did the bacteria that the government was concerned about make the frogs more susceptible to cold, thus the coincidental die-off at the same time as eradication was to begin?
- Will Welsh clawed frogs be the next species that we thought were gone but had just become better hidden?
I crave a one-hour documentary about this.
In the 1930s, two South African researchers, Hillel Shapiro and Harry Zwarenstein,[26] students of Lancelot Hogben at the University of Cape Town, discovered that the urine from pregnant women would induce oocyte production in X. laevis within 8–12 hours of injection.
-- from https://en.wikipedia.org/wiki/African_clawed_frog#Use_in_res...
The reaction is to Human chorionic gonadotropi - basically it's a marker which tells a human's body "You are pregnant, proceed accordingly". If you've got a womb and are in a reasonable age range this almost certainly means you're pregnant, if not it's a sign something went badly wrong. So, testing whether this marker is present means you know months earlier than you might otherwise.
Presumably the frog "Make eggs now" marker is different, but not different enough to ensure this effect doesn't happen, after all ordinarily frogs wouldn't be exposed to the urine of pregnant humans.
> Will Welsh clawed frogs be the next species that we thought were gone but had just become better hidden?
This isn't a rare species. It just wasn't in Wales and now it once again isn't in Wales. So that's like how Wales also does not have kangaroos. No danger the kangaroo goes extinct, there are lots and they're pretty competitive. But there aren't any in Wales (outside maybe a Zoo?) and so the ecosystem there does not have a kangaroo shaped niche.
https://en.m.wiktionary.org/wiki/the_rabbit_died
https://en.m.wikipedia.org/wiki/Rabbit_test
The frog was an improvement since you didn't have to kill the frog (apparently they could survive the urine injection).
FWIW the rabbit always died whether you were pregnant or not :(.
That made zero sense to me at the time.
This shows up in the Aerosmith song, "Sweet Emotion"
> FWIW the rabbit always died whether you were pregnant or not :(.
It's not that an injection of urine if a pregnant woman kills the rabbit.
It's like the rabies test on the brain. We cannot look at the brain before you're dead, because the act of looking at it would kill you.
I can see how this might be read in two different ways now.
I always think of this short story now:
Hormones are basically messages sent through an animal's body to signal some change should take place. It was discovered that there was a hormone called hCG produced by the human placenta that triggers "you're pregnant" changes in the body. hCG is also present in the urine.
So if you want to detect a hormone, the idea is you inject it into an animal and see if it triggers the relevant changes (since the changes are usually internal, you generally need to kill the animal to check). So you would look for an animal that responds somehow to the hCG hormone, inject urine into it, and check for the response. Mice and rabbits were first used, but it was eventually discovered that certain species of frog that are highly sensitive to hormonal changes made for much simpler and faster testing.
Yeah, it makes me think of how many dumb things scientists really did. I bet, that the most of them are unknown because nothing interesting happened.
Other than the intense suffering of "research animals." Come to think of it that might be why they're kept "unknown."
"After how the thing with the phlegm and the horses worked out, it's a hard no."
such an approach has long history - peeing on wheat is known from the times of Ancient Egypt and it was widely used in Middle Ages too
https://history.nih.gov/illustrated-histories/thin-blue-line...
"Bastard Executioner" series set in 14th century has a scene on using several objects to test urine for pregnancy on.
Estrogen extracted from pregnant women’s urine used to be used as a supplement for menopausal women. I read recently that some doctors would overprescribe urine tests during pregnancy, bill the patient and sell the excess urine.
Later as an estrogen supplement came Premarin, which is made from pregnant mares’ urine.
But as they admit, that's only one possible reason.
This story is from Wales.
They have some cells in the skin with black blobs full of melanin, and they can move them. Usually they are disperse and the color is dark, but with some hormone the blobs are transported to the nuclei of the cell and the color is light.
We used cells of this frog in a undergaduate lab for physics. The main task was to fine tune a microscope to track the blobs. So we cultivate the cells for a week (from a cell line, the original frog was gone long ago), we put the cells under the microscope and add an hormone to force the change of color in a minute or so. (I think in the wild the change of color is very slow.)
Something like this (not my video): https://www.youtube.com/watch?v=vqJSA_v0ics
Why? Annoyingly typical of the BBS to throw in that detail and not follow it up.
They kept it secret to not disturb the research they were conducting.