Radiolab: Mouse in amaze

Chest pains? Quick!! Pull my finger!!

July 16, 2008 – 8:00 am

Hydrogen sulfide stinks, but you knew that already, didn’t you. Hydrogen sulfide is flammable, but you probably knew that too (and I won’t ask how). But did you know hydrogen sulfide lowers blood pressure? and might protect the body from injury?

As little as 10 parts per million of hydrogen sulfide can irritate your eyes. 1000 ppm can kill you almost instantly. But some scientists like John Wallace of the University of Calgary say it also possesses some protective properties as low doses can stimulate gastric ulcer healing. It even protects mouse hearts from artificially induced heart attack says David Lefer of Albert Einstein College of Medicine. Of course, how all this works is a bit harder to squeeze out (sorry..) and some say it could be that the gas soothes the perturbed mitochondria in the cells, effectively dodging the trigger to self-destruct.

But the key to the little stink bomb’s success might have to do with Sleep. Mark Roth of the Fred Hutchinson Cancer Research Center has found that it can induce a sort of suspended animation:

Exposed to 80 ppm of hydrogen sulfide, mice enter into what we call a “hibernation-like” state, where their core temperature can be reduced as much as 11 degrees and their metabolic rate as judged by carbon dioxide production and oxygen consumption drops 10-fold. We’ve kept the animals in this state for 6 hours and they recover completely.

He and others in the field note that hydrogen sulfide and other mechanisms to alter the metabolic rate might make it possible to slow down the clock for trauma victims and preserve human organs for transplant. But nothing’s FDA approved.. so you don’t need to plug your nose at the ER just yet.

The Tooth Fairy is from Norway?

July 9, 2008 – 8:00 am

tooth1.jpg
curlyqcuties/flickr

Helene Meyer Tvinnereim and a team of Norwegian scientists are collecting milk teeth from 100,000 kids to create what may be the world’s largest tooth bank. A dental biomaterials researcher at U Bergen in Norway, Tvinnereim seeks to find links between diseases and prenatal/childhood exposure to chemicals. The normally discarded teeth function as a ‘black-box’ recording of the chemicals children are exposed to, and have excellent shelf-life when dried and stored. Of course, this is a lot easier to do when you have a streamlined national health-care and record keeping system..

The incredible, edible..

July 2, 2008 – 8:00 am

egg.jpg
Kagedfish/flickr

In the early 1940s, Esmond Emerson Snell (1914-2003) was trying to figure out why baby chicks who were fed raw egg whites (I know.. how cruel..) showed symptoms of biotin deficiency despite having plenty of it in the diet.

So who’s getting the biotin? Turned out the egg white itself just wouldn’t release the biotin for the chicks to use. So Snell purified the protein that held the biotin so tightly, which is no small feat today and even harder to do back then. He called it “avidin” (avid + biotin or “hungry for biotin”).

Snell said of his work: “The ability of this substance to take up and release biotin specifically and quantitatively suggests its possible use as a tool in the purification of biotin.”

He underestimated his contribution because this very strong and very reproducible interaction has become the foundation for probing all sorts of biological processes.

One.. two.. skip a few..

June 30, 2008 – 4:00 pm

counting.jpg
Hexadecimal Time/flickr

“Have you quantified that?”

Answering “no” to this question will usually trigger a collective humph from the crowd at a scientific meeting. We don’t want to know that there’s more or less of some biological activity unless you can say exactly how much different it is from normal.

Now Ron Milo, Paul Jorgensen and Mike Springer at the Systems Biology department in Harvard have attempted to sate this appetite for numbers with a new site called BioNumbers, which contains referenced entries for numbers like the total nasal epithelial cell surface area in a mouse nose (about 300 square millimeters in case you didn’t know).

And the Top Ten Bionumbers are?! drumroll…

1. Rate of ribosome translation in E. coli = 12-21 amino acids per second
2. Doubling time of cell lines in humans (check database)
3. Number of ribosomes/cell in E. coli = 6,800-72,000
4. Absolute abundance of tumor protein p53 in humans = 160,000
5. Number of mRNA/cell in E. coli = 1,380
6. Average number of neurons in the mouse brain = 75,000,000
7. Average number of neurons in the human brain = 100,000,000,000
8. Number of synapses for a “typical” human neuron = 1,000-10,000
9. Concentration of ATP in rat neuron = 2.59 mM
10. Ribosome + RNAn –> Ribosome·RNAn+1 in E. coli = 100 base pairs/sec

I know what you’re thinking.. How many BioNumbers are currently known?

..1718 and climbing.

Individualism or Interdependence

May 23, 2008 – 6:00 am

During our show Who Am I? we got worried that spending so much time thinking about the ’self’ would make us a little.. well.. self-centered. But what’s wrong with that? Nothing really, but apparently we wouldn’t do well on this puzzle.

psychology1.jpg
(Image: Keysar and Wu/Psychological Science)

The view on the left shows what the test subject sees. The view on the right shows what the ‘director’ sees. Following instructions from the director, student volunteers moved objects from one compartment to the next. But notice there are some repeated items, one of which the director cannot see. In order to move the correct piece, the student would have to consider the director’s view.

Q. So what was the difference between those who scored high and those who scored low?

A. Culture.

Students raised in the US scored lower than students brought up in China. A lot lower. So why do Chinese students solve this puzzle faster? Psychologists Boaz Keysar and Shali Wu at the University of Chicago say a culture of interdependence rather than individualism probably accounts for it.

The focal point

May 19, 2008 – 11:55 am

If you do not see the video please install the latest flash player.

Fluorescent microscopy can illuminate neurons genetically engineered to express fluorescent proteins. “Two-photon” microscopy is special because it lights up the fluorescent neurons only at the focal point allowing scientists to piece together multiple sections in order to obtain a 3D image.

So how does this “two-photon” technology produce fluorescence only at the focal point if the fluorescent laser beam is penetrating all of the surrounding tissue? The theory is that the chances of two low-energy photons hitting the fluorophore at the same time with enough energy to produce a fluorescent event are extremely slim.

Imagine you’re at a cocktail party and you’ve had a couple drinks. It’s a big room and even though you’re stumbling around, you haven’t bumped into anyone with enough force to spill your drink. Now shrink the room a bit. People are closer so you start bumping into them one by one. But what are the odds that you’ll bump into two people at the same time with enough force to spill your drink? The odds are slim to none. But when you shrink that room small enough (the focal point), the chances of bumping into two people (photons) at the same time is enough to make you spill the drink (fluorescence).

Biological voyeurism

May 14, 2008 – 11:00 am

Scientists communicate with pictures (graphs, images, flowcharts, etc) because it’s often impossible to convey experimental results with just words. So a picture is truly worth a thousand words, right?

I checked this out by dividing the total words by the number of figure panels in a few recent Reports to Science and Letters to Nature. It seems a picture is worth more like 606 +/- 381 and 296 +/- 97 words, respectively.

Doesn’t matter anyways, because scientists are all watching movies these days. Watch the neutrophil (white blood cell) below chasing the little bacteria.

If you do not see the video please install the latest flash player.

Lies are only skin deep?

May 9, 2008 – 2:00 pm

bocca2.jpg
Pancrat/flickr

Over the course of human history, the methods used to determine if someone is telling the truth have ranged from horrific to downright silly. The legend of La Bocca della Verita holds that if someone fibs with their hand in the mouth, it gets bitten off.

More recent research looks at brain activity during deception. We also interviewed Britton Chance about the possibility of remote lie detection using infrared examination of brain activity. New research directs our attention to the skin, where sweat gland activity may be detected from a distance. The helical structure of a sweat gland allows it to behave like an antenna for electromagnetic frequencies in the range of 100 GHz.

Skeptics note that this is just another way to detect stress, not lies. Even the researchers say the most appropriate application of the technology is to monitor medical patients or athletes.

Technology and Human Rights

May 9, 2008 – 1:53 pm

Many of you probably remember last year’s release of satellite images documenting human rights violations in Myanmar (Burma). Scientists have teamed together at the American Academy for the Advancement of Science (AAAS) to use sophisticated technology to alert us of the atrocities against civilians in Darfur, North Korea, and Burma. How else can we apply the tools of science to enhance human rights work?

0928burma_report.jpg
A bamboo fencing around a military encampment appears in Burma on Dec 13 2006.
Top image: © GeoEye, Inc.
Bottom image: © 2007 DigitalGlobe.

A formula for the perfect joke

May 5, 2008 – 6:28 am

mrbean.jpg
Firstposter Showcase/flickr

In our research on the show Laughter, we came across Dr. Helen Pilcher’s formula for writing hit British comedy.

x = (fl + no ) / p

where funniness (f) of the punchline times length of build-up (l) is added to the amount someone falls down (n) times the physical pain or social embarrassment (o for “ouch”). All this is divided by the pun (p), which reduces laughter and produces more of a groan.

The story was picked up by Robert Siegel a while back.

Skeptics noted that the equation is not really based on any real research and see it as just another installation in the endless abyss of junk math including formulae for biscuit dunking and the perfect cup of tea.

I love spontaneity in my comedy, but I’m a sucker for slapstick too. Keep in mind Americans seem to differ from the British in their opinion of nasty jokes according to some recent studies. How do you take your humor?


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