Waching daily Apr 27 2018

[ INTRO ]

Earlier this week, you might've noticed headlines about how having asthma or hay fever

can increase your risk of developing a mental illness.

But you don't have to worry and run off to your doctor.

These headlines are reporting on a study published this week in the journal Frontiers in Psychology.

And if you take a closer look at that paper, the results aren't as clear — or dramatic

— as they might seem.

Your body is one giant interconnected system, so it makes sense that some diseases might

be related or have the same root cause.

Researchers have spent a lot of time looking into this idea, especially when it comes to

psychiatric disorders and allergies.

Allergies are when your immune system overreacts to something harmless, like animal dander,

and treats it like a threatening invader.

And some studies have suggested that the stress or inflammation from how our bodies fight

allergens could throw off brain chemistry.

Admittedly, the research is ongoing, and a lot of things are up for debate.

But if it's true, and if we understood how that connection worked, we could maybe prevent

some mental illnesses.

So far, studies have mostly focused on links between specific conditions — like schizophrenia

and being allergic to things like pollen.

What's special about this new paper is that it looked at the likelihood of someone with

certain allergies developing any psychiatric disorder.

Specifically, this team looked at patients who had three of the most common allergic

diseases: asthma; allergic rhinitis, which is sometimes called hay fever; and atopic

dermatitis, which is a kind of eczema.

Using a national database from Taiwan, the team collected 15 years of health data from

over 180,000 patients.

Almost 47,000 had these allergic diseases, and around 140,000 didn't.

Then, the team calculated how many people with allergies were /also/ diagnosed with

a psychiatric disorder over that decade and a half — something like anxiety or depression.

And the results were kind of surprising.

They found that almost 11% of those with allergies developed some kind of psychiatric disorder,

while only about 7% of the control group did.

In general, that meant the people with allergies were statistically about 1.66 times more likely

to develop a mental illness over that 15 years.

Now, just because these data suggest that these conditions might be related doesn't

mean that one causes the other, or that they definitely come as a pair.

For instance, the team also found that those who just had eczema, or who had hay fever

and eczema together, actually had a lower risk of developing psychiatric disorders than

the control group.

Also, the data from this study came from only one population, so it might not be representative

of everyone.

Besides, a risk factor of 1.66 really isn't that high, especially if you compare it to

the risks associated with things like genetics.

So it's not actually that alarming.

Not to mention, scientists still have to figure out the mechanisms that could link allergies

to mental illnesses — which this study didn't look at.

So if you get sniffly in the springtime, don't worry about your health any more than you

normally would.

On a much smaller scale, a team of researchers announced on Monday in the journal Nature

Chemistry that they've found a new form of DNA hiding in your cells!

It's called an i-motif.

And it's not, like, changing how we think about humans as a species or anything.

But it can help us understand how our DNA gets processed in our cells.

When you think of DNA, you probably think of the textbook double-helix structure, which

was discovered in the 1950s.

But for a while, scientists have known that strands of DNA come in at least a couple other

shapes.

Instead of looking like a twisted ladder, the i-motif looks like one strand of DNA got

tangled in a knot.

To make that happen, DNA's building blocks — called nucleotides — pair together in

a weird way.

Normally, cytosine bases always pair up with guanine.

But in the i-motif form, cytosine pairs with other cytosines.

I-motifs form in parts of DNA that are cytosine-rich.

Part of one DNA strand folds over itself and gets bunched up, so the other strand is alone.

It kind of looks like one side of a zipper got twisted into a knot.

This happens because one of the cytosines gets an extra proton from its environment

and becomes slightly positively charged, while the other stays neutral.

So they can bind.

Researchers had observed the i-motif structure before in test tubes, but now, we've seen

it in a few kinds of living human cells!

Like epithelial cells, which do things like line your organs.

To track down this elusive DNA, the team designed a new antibody fragment from pre-existing

molecules.

Antibodies are proteins your immune system uses to track down invaders, so they're

really good at binding to specific substances.

This one was made to cling to i-motif's funny structure, and to glow under certain

lights so the scientists could know where it was.

And it worked like a charm!

After tracking the i-motifs for a bit, the team also realized why they might've been

hard to find: these structures don't exist all the time.

Mainly, i-motifs form during the G1 phase of the cell cycle, when DNA is being read

by other molecules to make proteins and get ready for cell division.

Once that phase is over, most i-motifs seem to go away.

Although it's not clear if the DNA changes shape by itself, or if another molecule helps

untangle it.

Either way, this suggests that i-motifs are mainly involved in helping dividing cells

express certain genes and make certain proteins.

So even though it's been over 50 years since we first discovered the main structure of

DNA, we've still got so much to learn about it.

Thanks for watching this episode of SciShow!

We're able to bring you new science news every week thanks to support from our Patreon

patrons, like Matthew Brant, our president of space!

If you'd like to be president of space, submit questions for us to answer, or join

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[ OUTRO ]