Episode 2 Incredible Medicine: Dr Weston's Casebook

We're discovering astonishing things about the human body

all the time, through people who are different from most.

I'm Gabriel Weston.

As a surgeon, I've spent years studying the human body.

And the secrets of how it works are often revealed by the most

rare and surprising of cases.

So I've searched the world to find these extraordinary people

and bring you their stories.

This is my heart. I'm the only one that has this.

I'm Jordy Cernik and I can't feel fear.

My name is Harnaam Kaur and I'm a fabulous bearded lady.

With the help of the doctors that treat them and some of the

world's leading scientists,

I'll be uncovering exactly what makes their bodies unique.

I'm going to show you the hidden processes

that make them exceptional.

Just look at that!

I'll discover how they're leading us to the cures of the future.

When we make a breakthrough like this, it is very exciting.

And I'll use the latest technology to uncover the secrets of

their bodies and reveal how all of these cases are giving us a new

understanding of the most amazing natural machine on the planet -

the human body.

The world is full of threats to our survival,

some we're aware of and some we can't see - and our bodies are

constantly adapting to these dangers from within and without.

In this programme, we'll meet some remarkable individuals

who push this ability to the absolute limit.

We'll discover how this man can survive for two hours in ice...

How this woman can live with only half of her brain...

Why this man can't ever feel fear...

And why this is the only man on earth to survive

the world's most notorious virus.

In our first few cases,

we'll meet some truly extraordinary people - mavericks who are

exposing their own bodies to some of the greatest perils in the

natural world and uncovering hidden survival mechanisms in all of us.

The first of these pioneers seems to defy the laws of nature.

I can withstand the venom from the world's deadliest snakes.

Steve Ludwin has an unusual and highly dangerous habit.

He regularly injects himself with deadly snake venom,

yet he is still alive.

All my life, I've been, you know, reading about snakes,

seeking them out.

I started keeping snakes when I was six years old.

It was as a child that Steve came across the idea

of injecting their venom.

My father took me down to the Miami Serpentarium and I got to see

this guy called Bill Haast.

He's the first Westerner who started injecting himself with snake venom.

Snake enthusiast Bill Haast believed that snake venom may have

healing properties and therefore had been injecting it into his blood.

It just blew my mind as a kid, I was like, wow! It really stuck with me.

By the time when I was 17 years old,

I just had this light bulb moment where it's like,

"I'm going to do the same thing, I'm going to try and copy him".

Steve has now been injecting himself with venom for nearly 30 years.

He's about to take some from a viper from his own collection

of snakes.

You get the snake safely behind its head and you have

a glass with some plastic over the top, a bag, or something like that.

You hold the snake up and the snake bites into the glass,

deposits the venom and that's it, it's over.

It's very quick and painless for the snake.

This particular venom is what's known as a haemotoxin - one

that affects the blood and blood vessels and it CAN be fatal.

Steve places some venom on his arm and then uses

a needle to break the skin.

So, yes - here we go.

And that's just taking the venom down.

It's not a pleasant feeling, you can feel it burning instantly.

Steve is lucky to be alive.

Let me show you what happens when venom enters his blood.

Here, I've got a dish of my own blood and here,

in this little vial, I've got some real snake venom.

Just wait and see what happens when I pour some of the venom into

the dish of my blood.

This is a hemotoxic venom, like the one Steve injected.

So what I can see here as I swirl this round is that the blood

is becoming dark and sort of solid in areas, it's like

a jelly and you can imagine if this blood was running through your

vessels, the blood would basically stop and that's why you'd die.

Even a small blood clot can be fatal.

So how has Steve survived?

My blood is unique, only because I have almost 30 years of doing

this and it's not magic, it's not voodoo or anything - anybody

could have done what I've done.

Steve's gradual exposure to snake venom

has worked in the same way as vaccinations do in most of us.

Vaccines give us a low dose of a virus or toxin - not enough

to harm us, but enough for our body to learn to fight it and

protect us from it in the future.

Our immune system does this by producing specialised defence cells

known as antibodies.

Each type of antibody is a unique shape to target

a particular virus or toxin.

When Steve embarked upon his daredevil experiment,

he started with extremely low doses.

His body learned to recognise different venoms and produce

specific antibodies to fight each one.

My body reacts differently - my body seems to not swell as much

and when it does swell, it seems to recover a lot quicker.

Steve's dangerous habit started as a personal challenge.

But now, he's caught the attention of scientists working in Denmark.

At the University of Copenhagen,

pharmaceutical engineers Andreas Hougaard Laustsen and Brian Lohse

have been trying to develop an antivenom to treat snakebites.

A snake bite is a much bigger problem that what most people are aware of.

It is considered as the most neglected of the neglected

tropical diseases.

The estimate is that around one million bites occur in

sub-Saharan Africa and probably around 50 to 100,000 people

die each year from snake bite.

If you're bitten by a venomous snake,

the only treatment is a dose of antibodies, known as antivenom.

But there's currently a global shortage and the antivenom

that does exist is produced in horses and so carries

a significant risks to humans.

The human immune system would recognise that this is from

a horse and it will cause adverse effects and in the worst cases,

administration of antivenom can even lead to death of the victim.

Not from the snakebite itself, but from the antivenom.

To make a safe antivenom, they'd need to find

a way to produce antibodies from human blood, not horse blood.

They thought it would take ten years to do this in a laboratory.

But then they heard of Steve - here was the ready-made

source of the antibodies they needed.

Instantly, they knew it was a unique opportunity.

The scientists are now working with Steve's blood to collect the

crucial antibodies and replicate them on a mass scale.

Our goal is to develop the first antivenom based on human

antibodies that can target all medically relevant snake

species in sub-Saharan Africa.

When we've done that, our next goal is to expand the antivenom or

develop further regional antivenoms based on the same principle

for other continents of the world.

Steve's involvement in the project has meant the scientists are much

closer to producing new antivenoms that could save millions of lives.

I can dine out with a smile on my face,

that I've achieved something, I've done something positive.

And I feel really good about it.

Steve's dangerous experiments on himself are helping to

advance medical science.

And through the history of medicine,

some of the biggest breakthroughs in understanding how our bodies

respond to threats and disease,

have come from extraordinary

individuals who've put themselves at extreme risk.

One such pioneer is Australian doctor Barry Marshall.

In the 1980s, he and his colleague Robin Warren

became very interested in a bacterium

called Helicobacter pylori.

Now, the reason for their interest was that they were sure that

this was what was causing stomach ulcer disease, which is a

horrible condition that was thought at the time to be caused by stress.

The difficulty for them was proving their case

to the scientific community.

They needed to clearly show the bacteria led to ulcers,

but it would have been unethical to test their theory on people.

And this left Barry Marshall with just one avenue - to

experiment on himself.

So what he did was he gathered H pylori

from the stomach of his patients, mixed it into a broth and drank it.

It didn't taste very well - it was like swamp water or

something, it was quite putrid, in fact, so...

It was a little revolting to do.

And then on the eighth day,

I suddenly woke up in the morning, 6am,

felt very nauseated and ran into the bathroom and vomited in the toilet.

Sure enough, within a few days,

he developed symptoms that come before an ulcer.

He then took a biopsy and this proved the link between H pylori

and ulcer disease,

turning a condition that had been chronic and debilitating into

a simple disease that could be cured with a dose of antibiotics.

This is Barry Marshall and Robin Warren receiving the

Nobel Prize for their discovery.

Even now, advances in modern medicine are being made

possible by a few pioneering individuals who are prepared

to put their bodies in the service of science,

as our next remarkable case shows.

My name is Wim Hof - they call me the Iceman. I'm 57 years old.

Wim is a world record-holder in enduring extreme cold.

On Kilimanjaro, we go up to the summit in shorts.

Africa's highest point.

He has set records for swimming beneath ice.

And being immersed within it.

In most of us, if we're exposed to extreme cold,

our core temperature drops.

If it falls by just 2 degrees, we become hypothermic.

Our heart and respiratory system will soon fail.

Most of us would lose consciousness after just 15 minutes and

would die within an hour.

But Wim Hof can spend nearly 2 hours in ice and emerge unharmed.

So how is he able to survive?

A team of researchers at Radboud University Medical Centre

in the Netherlands set out to discover the answer.

They took some key measurements to find out exactly what happens

in Wim's body when he's encased in ice.

Matthijs Kox is a researcher at the University.

All kinds of things are measured, so we measured metabolism, we

measured of course his skin temperature

and all kinds of other biometrics

to learn more about this interesting ability of his to withstand extreme cold.

The tests revealed that when he's in ice,

Wim's core temperature doesn't drop as you'd expect.

It actually goes up slightly.

It sounds impossible,

but the scientists have found the answer in his blood.

So what we actually found is that the adrenaline levels in the

blood went up to very high levels and they were actually higher

than in subjects that bungee jumped for the first time.

Adrenaline is a hormone that our bodies produce automatically

when we're faced with danger.

It has many effects on the body,

one of which is to raise our metabolism, which generates heat.

But adrenaline is not something

most of us can consciously choose to produce.

Wim claims he can do it, thanks to a special breathing technique.

Anybody can do it. I can prove it.

Belly first...

Then chest.

Then the head.

Letting go, not fully out.

But fully in... And then letting go.

If you do that 30 times, I promise you,

you are able to do all kinds of things.

Though it may sound unlikely,

there is a good scientific reason why this unusual breathing technique

might cause the body to produce more adrenaline.

The deep inhalations followed by quick exhalations

expel more carbon dioxide from the lungs than normal.

As a result, levels of carbon dioxide in the blood

drop dramatically.

This makes it more alkaline, which is measured as a higher pH reading.

So, with the breathing technique,

what we see in the blood is that the pH goes up to very high levels

and this might be involved in triggering of adrenaline release.

The level of control that Wim over his own body is remarkable.

By simply breathing in a different way,

it looks as if he's able to control his own blood chemistry

in a way that perhaps enables him to produce more adrenaline -

and it's this that lets him withstand

extreme temperatures of cold in an almost superhuman way.

But Wim says it also lets him do something even more impressive.

I told them I could influence the immune system.

On the face of it, it sounds like an outlandish claim -

our immune system responds automatically

to protect us when our body comes into contact with disease.

We don't have conscious control of it.

So Wim actually came to us with his claim

that he could influence his immune response,

so that was interesting to us,

because we actually study the immune response in our department.

Matthijs's team knew that one of the things that can influence

the immune system is adrenaline - so could Wim be right?

The only way to find out was to test Wim's immune response.

Whilst he breathed using his special technique,

the scientists injected him with a substance called an endotoxin,

which tricks the body into thinking it's under bacterial attack.

The normal immune response would be fever and flu-like symptoms.

When we injected Wim with this bacterial compound,

his immune response was much lower

than what we observed in over 100 volunteers.

We saw less fever, he had less flu-like symptoms

and he also had lessened concentrations

of inflammatory proteins in his blood.

The tests show that Wim's technique

might actually suppress his immune response.

And this is a really exciting discovery,

because there are a whole set of common diseases

where the immune system goes into overdrive and even attacks itself.

So in autoimmune diseases,

your immune system actually attacks your own body,

actually - parts of your own body

and that is actually an inappropriate immune response

that you don't want.

The most well-known autoimmune disease is rheumatoid arthritis.

It may be that Wim's special breathing technique

could help people with autoimmune diseases

to suppress the immune response that is causing their illness.

Now, Matthijs is investigating whether breathing in this way

affects others the same way as Wim.

Half of these men are breathing using Wim's technique

and half are breathing normally.

Over the coming months,

Matthijs will be running a number of tests

to look for any differences in their adrenaline levels

and immune response.

The real test is going to be when we test these techniques

in actual patients with autoimmune diseases

and when we can show that these are also effective in these patients,

these techniques,

then this could mean a new way of treating these patients.

So, these breathing techniques

I've been developing by feeling, intuition.

When I had no scientific validation,

they called me an idiot, they called me crazy -

AND yes, it has been shown in scientific experiments

it all works, so...and greatly - not a little bit, big-time.

Wim is adding a new chapter to medical science.

By pushing himself to the absolute limit,

Wim Hof is changing scientists' understanding of how the body works.

But in some cases, the body is forced to adapt

not in response to an external threat,

but because of a threat from within,

when a part of the body itself goes wrong.

Our next case almost defies belief and reveals the human body

as being capable of adapting in ways that I, even as a doctor,

would never have imagined possible.

INDISTINCT SPEECH

Jodie Graves is living proof of the incredible resilience

of the human body.

You wouldn't know now looking at Jodie, in her mid-20s,

leading a full life,

what an incredible thing that she went through at the age of three.

I have half a brain.

When people meet me, they have no idea.

Jodie began life as a completely normal baby and toddler.

And the very first time that they noticed anything that wasn't

quite right with her was around the age of three,

when Jodie, very suddenly one day, just collapsed.

I only remember my very first seizure.

I was at my day-care playing and the next thing I knew,

I was in an ambulance.

We hightailed it to the hospital and just watched her.

She had another seizure the next morning,

so I ran her into the hospital again.

But nothing that they did...worked.

From that point onwards, things really snowballed for her

and she began to have fits on a really regular basis.

If you picture a marionette with the strings,

it was like someone just dropped one side.

So she was constantly falling to the left and it got so bad

that one of us had to be on her left side all the time.

It was to the point where I was having seizures every three minutes,

and that wasn't...cool.

Jodie's parents were so worried that they took her to

the world-renowned neurology department

at the Johns Hopkins Hospital.

Investigations there showed she was suffering from

a rare condition called Rasmussen's encephalitis.

This causes chronic inflammation of the brain,

usually in one hemisphere.

Without treatment, there was no prospect

that Jodie's seizures would ever stop.

There was one possible option, but it was shocking.

The doctor explained that the only way they

could treat it was to take out the half of the brain that was affected.

As a doctor, I have never heard of this kind of surgery.

If somebody had said to me, "What do you think would happen if you

"took half of someone's brain out?"

Um, I would've thought that that would be

devastating, if not fatal.

Amy Bastian is Professor of Neuroscience and Neurology

at Johns Hopkins.

Having an entire hemisphere of your brain removed

is a pretty radical thing.

It's not something that any neurosurgeon would do lightly.

So how is it possible to have such a drastic operation and still survive?

Well, Jodie's doctors hope that if they took out the right-hand side

of her brain, the left hemisphere would compensate

and take over its functions.

This is because of something called brain plasticity,

the remarkable ability of the brain to adapt and reorganise itself.

In very, very early childhood,

the brain is thought to be in one of its most plastic states.

And if you change the brain at that point,

there may be a better capacity for the brain to reorganise.

The doctors were optimistic that this would work for Jodie.

The operation had been performed in over 50 patients

and had been successful.

But her parents had mixed feelings about going ahead

with such a drastic procedure.

Basically, I said, "No,

"this sounds like a good deal, I can have my child back,

"she'll be at least as good as she is now but without the seizures."

So my reaction was very atypical.

I was mostly relieved that there was something we could do.

My husband's reaction was much more typical.

When we walked out to the garage and got in the car,

I just totally exploded. I just lost it, right there.

Well, you know, she was his little girl.

It took him a couple of weeks to get used to the idea,

and to agree that it was the best thing that we could do for her.

I was glad that my parents were right there beside me

through the whole thing.

Jodie had her operation when she was just three years old.

Nobody could know if it had been successful until she woke up.

She gave Dad the thumbs up - that was their sign,

so, we knew she was comprehending things, and she was not seizing.

That was a really big difference.

Amazingly, then, Jodie just continued to do really, really well.

As a young child,

she carried on doing all the things that she wanted to do.

This may have been because her brain had already started

to rewire itself, even before the operation.

You can imagine, if you had a hemisphere of your brain,

half of your brain, that was sick,

that was having seizures and was not functioning normally,

and you're a little kid, and your brain is still developing,

the other side of the brain is pretty healthy,

and is able start taking over some of those functions,

and that's probably why, when you take out the hemisphere,

that these kids actually do really quite well.

They've been dealing with the sick hemisphere for so long

that the function - much of the function -

has transferred to the other.

Thanks to its remarkable plasticity,

the remaining half of Jodie's brain is able to control her entire body.

I'm a very positive person -

a lot of times I'll joke that they took out the mean side of my brain,

and they only left the happy side.

For me, as a doctor, Jodie's story is a really inspiring example

of the fact that our bodies may be capable of a whole lot more

than we think they are, if only we're prepared

to give them that chance.

Life now, with half a brain, for me, is no different than anybody else.

So, I've been married for years, I live on my own with my husband,

I work - I work with a little boy with ADHD,

and I do everything that any other person would do.

I don't get cut any breaks.

If you had asked me 25 years ago

if it was possible to take out half the brain

and still have functioning life,

I would have said, "You've got to be crazy,"

but here we are.

I'm really glad my parents did what they did,

because I wouldn't be where I am now

if I had had the surgery any later or had waited any longer.

Jodie's case shows the power of the human body to adapt physically,

even after the most extreme trauma - but, to survive,

we rely on more than the physical structures of our body.

There's another key part of our make-up

we depend on far more than we realise.

Our emotions.

Emotions are a crucial part

of how we will respond to the world around us,

and our next few cases are going to focus on one particular emotion.

Fear.

We are hard-wired to respond instantly

to certain threats or alarm signals.

It's a process that's vital for our survival,

and one of the most amazing cases I've seen recently

is that of a man who's completely lost this ability.

In 2013, Jordy Cernick did a tandem skydive for charity.

He'd never jumped from a plane before.

You get to the point where they get you to dangle your legs

outside of the plane, of course, you feel the wind

and you can feel all the noise.

For most of us, this would be one of the most terrifying moments

of our life - but not Jordy.

I didn't feel a thing. There was no reaction.

I'm Jordy Cernick, and I don't feel fear.

But Jordy wasn't born this way.

His journey to fearlessness began in the late 1990s,

when his body began to change.

I was quite a slim, physical guy.

I had done stuff in the Army, and I was quite healthy.

I started putting on quite a bit of weight -

and I did lots of diets, I did all the fad diets you can think of.

I trained up to six, seven times a week,

and nothing was shifting this fat that I was gaining and gaining.

Jordy was eventually referred to a specialist

and diagnosed with a rare condition called Cushing's syndrome.

It makes you fat, it makes you have high blood pressure,

it makes you sweat, and it's very dangerous.

It's the high blood pressure side that's so dangerous,

and can kill you.

Cushing's syndrome is caused by abnormally high levels of cortisol,

a hormone we produce in response to stress.

It can affect our appetite and our blood sugar,

and this is what had affected Jordy's weight.

Cortisol is produced by the combined action

of the pituitary gland in the base of the brain

and the adrenal glands just above the kidneys.

The only possible treatment was an operation.

They decided to completely remove my adrenals.

Now, that meant they had to open up the left side of my body

and just take the adrenals out that way.

After the procedure, Jordy return to his normal weight -

but he soon noticed something else was missing.

We decided to go away for a couple of days on a family holiday,

and we ended up in a theme park, and I remember going up,

and it was getting higher and higher and higher,

I was just thinking, "It's going to kick in.

"I'll just get ready for it," and it dropped...

Whee!

..and I felt nothing. All I felt was the movement.

And I thought, "You know what?

"I know there's something not right here."

Jordy began to realise he could no longer feel fear.

Normally, the sensation of fear

is caused by a combination of hormones

produced in our bodies by particular glands.

Now, these are the kidneys, here, and sitting on top of them,

the adrenal glands, and in response to the situation of threat,

these glands produce hormones like cortisol and adrenaline,

which quickly enter the bloodstream. This increases the heart rate

and, at the same time, it floods the blood and the muscles

with energy and nutrients,

as well as shutting down the less important processes -

all of which puts us in the best possible position

to either escape danger or rise up to meet the threat of it.

It's one of the oldest emotional responses to the world around us.

But Jordy had had these glands removed

to treat his Cushing's syndrome,

and, as a result, he could no longer produce adrenaline.

For scientists, Jordy presents a rare opportunity

to understand how fear works.

Now, it's long been known that adrenaline

plays a key part in how our bodies respond to danger,

but without the glands that produce it,

is there anything left of our sense of fear at all?

Dr Sarah Garfinkel is a cognitive neuroscientist

from the University of Sussex.

She's going to set up an experiment that's never been tried before

to test exactly how Jordy's body responds to a situation

that would ignite fear in most of us.

This is the National Lift Tower in Northampton.

It's 127 metres tall, and Jordy is going to abseil down it.

Now what I want to do is put these bands on you.

As he descends, Jordy will wear these bands

to measure what's known as skin conductance.

These are going to stay on you as you abseil down.

When we feel fear, moisture levels in our skin

increase by tiny amounts,

and this makes it a better conductor of electricity.

The band will detect any such minute changes in Jordy.

If his body isn't displaying these typical fear responses,

then that means that he's not getting

the body saying, "I'm scared,"

and if the body is not saying, "I'm scared,"

then it's not telling the brain, "I'm scared,"

and then you don't get this sort of feedback loop.

In most of us, fearful emotions are controlled by a part of the brain

called the amygdala.

When we face a threat or danger,

it signals different parts of the brain and body

to spring into action,

triggering a cascade of responses in the hormone and nervous systems.

Normally, this includes the release of adrenaline.

-Right then.

-OK.

-Let's do this.

-Good luck.

-I'll see you at the bottom.

-Good.

-Ready?

-Yeah.

There we ago.

Going over the edge

is the moment you'd expect would trigger

the cascade of fear responses.

The experiment will show whether, with adrenaline missing,

any of the system still works in Jordy.

Dr Garfinkel can now analyse the data

collected during Jordy's descent.

That's where you should be seeing this line here,

so I know, on the graph, where you are just starting your descent.

This graph plots that any change measured in his skin conductance.

And what is so interesting about this graph is,

where we would expect there to be a big peak,

there is absolutely no rise at all. It's completely flat.

You've got, like, the tiniest little bump there.

That's telling me it is working and it is reading -

you're just not having a response.

The experiment has shown that, without adrenaline,

Jordy's entire fear response has broken down.

But what's most interesting about Jordy

is that he can still perceive risk and keep himself safe,

and this is because he still has a vital part

of the fear of response system in place -

the amygdala in the brain.

This tells him when a situation is dangerous.

He knows he should be scared, he just doesn't feel scared.

So I'm going to attach this to your finger...

Sarah, Jordy's rare ability to perceive fear but not feel it

is an opportunity to understand other medical conditions

where fear becomes debilitating - like anxiety.

Jordy doesn't have the subjective feeling of fear,

and his body is also not showing the fear response,

and we can take that, based on Jordy,

and apply it to people with anxiety,

who have too much fear, to try and understand more

how novel treatments can potentially be used

to treat people with anxiety.

All the stuff that's gone wrong, why not think, "You know what?

"I've been able to help somebody

"who has such anxiety that they can't go out the house."

Wow!

It would be great to think I've been able to help somebody.

Jordy's case reveals just how much we depend

on that fundamental emotion - fear.

It's an instant and automatic response to our nervous system

when we encounter danger,

and is probably our most important survival mechanism,

and there's one extreme and rather noisy case

which is casting new light on how it's triggered.

My name is Jill Drake, and I have the world's loudest scream.

SHE SCREAMS

Jill Drake doesn't look like someone

who is likely to make your blood curdle...

-Hello.

-How are you?

-Fine, thank you.

-What have you got there?

-I've got a latte.

..but, by chance, she discovered she had an unusual talent.

It was Halloween time and there was a screaming competition going on,

and I screamed, and I broke the world record.

And then they said, "Can you do it again?"

So, I screamed again, and I broke the world record again.

The volume of the average person screaming is around 100 decibels.

Jill's was measured at 129.

SHE SCREAMS

Before she stumbled across the competition,

Jill had no idea that she could scream so loudly.

I'm always getting asked what training do I do,

and I don't - I just opened my mouth and it comes out, so...

It's loud!

When we scream, our lungs push air through our larynx

and over our vocal cords, which vibrate, making a sound -

but there aren't many people who can make a sound like Jill.

So, what enables her to generate this world record-breaking volume?

At the Royal Holloway University of London,

Professor David Howard is an expert on the human voice.

Ahh... Ahhh...!

This model is a model of the larynx.

There are two vocal folds, and when we're breathing,

the vocal folds are apart, so the airway is unobstructed -

but when we want to speak or sing,

we move the vocal folds close together

and air is then passed between them,

and they start to move towards each other,

and they crash together.

How much they crash together, and with what force,

determines the loudness of the sound.

To discover why Jill can produce such an ear-splitting volume,

David is going to measure exactly what's going on in her throat.

We're going to do that with this little device

that sits on the neck with two little electrode rings.

Pop those, one either side,

-and we're going to take a sound level at the same time.

-OK.

And there's one more vital piece of equipment that David requires -

earplugs.

And we're ready to go.

SHE SCREAMS

120.1.

That's very loud -

not the sort of levels you'd want to listen to for very long.

-Not bad at 65.

-It's very impressive at 65!

RECORDED SCREAM

David is now able to analyse the results,

and uncover why Jill has such a loud scream.

Your vocal folds are working very fast and rapidly.

That helps give this bigger acoustic output.

But, in order to do that, you need two things,

I believe - I think you have very efficient lungs,

in terms of how you can get the air out,

and I suspect your vocal folds are rather bigger

than for another lady of your age, so that when they do crash together,

there is more bulk there to give that really strong acoustic output.

SHE SCREAMS

But, in fact, it isn't the loudness itself

that makes a scream strike fear into us.

Well, we first, I think, have to think about,

why do humans scream at all?

To which I think the answer is,

it's to gain attention when we are in trouble.

So, during the scream, there are these rapid volume changes.

This graph shows the volume during Jill's screen.

In normal speech, the peaks would be all the same size,

but here there is a lot of variation.

And the research has shown that for the ear of the listener,

those rapid volume changes trigger a fear sensation in the brain...

THEY SCREAM

..and they tell the listener that something is going on

that they need to be afraid of, and somebody's in trouble.

Not only is Jill's scream record-breaking for its volume,

but it's also scientifically proven to be terrifying.

SHE SCREAMS

Jill may be extreme,

but her case shows how we can all produce particular sounds

that trigger fear in other people,

and this spurs us to respond to a threat.

It's an elegant example

of how our emotions can become a vital survival mechanism

that helps keep us safe -

but I've come across one extraordinary person

whose emotions are doing quite the opposite.

Lucy Tonge has a rare condition that can strike at any time,

putting her in imminent danger.

When we were on holiday couple of years ago,

I was with my mum and my sister, and we were in the swimming pool,

and I can't remember specifically what it was -

I think my sister said something that made me laugh -

and I just had my cataplexy.

Triggered by her laughter,

Lucy's muscles suddenly became weak and she lost control of her limbs.

I was in quite deep water - I just started drowning,

and it took them a while to realise.

This wasn't a one-off. Lucy has a condition called cataplexy.

It means that when she experiences a strong emotion,

it causes a sudden and extreme weakness in her muscles.

A lot of the time it's just my head and my neck,

but it can be anything from that to walking along and my knees go

or, like, full body collapse.

Things like adverts of dogs for the blind or donkey sanctuaries -

things that people might think, "Oh, that's sad,"

but I will just end up having cataplexy at things like that!

Along with cataplexy,

Lucy has a second condition whose symptoms are no less extreme.

On an average day, I'll usually have somewhere in the region

of 40 or 50 attacks where a fall asleep.

This is known as narcolepsy.

We all know what it feels like to be so tired that you just nod off,

but Lucy doesn't have to feel tired to fall asleep -

in fact, she loses consciousness without warning

up to 50 times a day,

and frequently loses control of her muscles.

So, what on earth is causing this to happen?

This is Emmanuel Mignot,

a professor of psychiatry...

Up, up, up.

..and this is a key member of his research team.

Watson - a narcoleptic Chihuahua.

Dr Dement, my mentor, was describing a number of sleep disorders

to the public, and then, one person, who was a veterinarian,

came to him and said, "It's just amazing, I mean,

"I have a dog with your problem, narcolepsy."

When it gets excited, you know, it falls down and it's paralysed,

and it sleeps all the time.

So, that gave the idea to Dr Dement

that maybe one of the ways we could find the cause of narcolepsy

was to try to study these dogs.

Dogs are a good model for studying human conditions,

as they share many of the genes found in the human diseases.

So, the team embarked on a search for narcoleptic dogs.

One of their canine recruits is Watson.

For him, the excitement of some tasty food

is enough to bring on an attack.

You see?

So, he got completely excited by the food,

and he got completely paralysed.

He has no more muscle tone - the same way as patients with cataplexy.

Ah, he's coming back. Oh, we survived! C'est bien!

C'etait beau, huh? C'est beau. Chicken! Chicken was good.

To search for a clue to the mysterious condition,

the researchers began to examine the genes of the narcoleptic dogs.

They were looking for an abnormality that all the dogs had in common.

After ten years combing through the dogs' DNA,

they finally found what they were looking for -

a fault in one particular gene.

It was a very new gene that had been described only one year before,

and it was a receptor for a chemical in the brain called hypocretin.

Hypocretin is a brain chemical that is known to help us stay awake.

So, that was very exciting,

because it suggests that this receptor and chemical

were maybe very important for narcolepsy and sleep in general.

Now, Professor Mignot wanted to find out

if hypocretin was also involved in humans.

He looked inside the brains of people with and without narcolepsy.

This is the brain of a normal person,

and, as you can see here, there is all these black dots,

and they represent little cells that are producing hypocretin -

and this is a picture of a patient with narcolepsy.

As you can see, all of the black dots are gone,

so there is no cells that is producing hypocretin.

At last, it seemed they'd found the cause of narcolepsy.

So, of course, we were very, very happy about that.

I turned around several times around my house to get calmed down.

When Professor Mignot investigated why people with narcolepsy

are lacking these hypocretin cells within the brains,

he discovered that something was destroying them -

the patient's own immune system.

This is what's known as an autoimmune condition.

The immune system is turning back on itself and attacking its own cells

in a way that means that cells that are meant to produce hypocretin

to keep us awake are not producing it in the way they should.

So, narcolepsy is helping to uncover how autoimmune diseases work

by turning on our bodies' own cells in particular ways...

..and now that Professor Mignot understands

how it affects the cells in our brain,

he believes he can find a way to treat it.

In the further future,

we might be able to replace, really, the hypocretin cells,

which would be a cure for people who have narcolepsy.

So, the landscape of narcolepsy has completely changed.

We have a serious hope for treatments

that are going to be very different from the ones we are using now.

At the moment, the treatments for narcolepsy

are not terribly effective, and what Dr Mignot wants to do

is find a way of re-establishing those cells

that are not producing hypocretin

in order that an actual cure for narcolepsy could be found.

The future is promising for Lucy and others,

with her rare combination of cataplexy and narcolepsy -

but, for now, she's not letting her condition hold her back.

Hello, you're listening to the politics show

with me, Lucy, on Smoke Radio.

We'll be talking about World Mental Health Day and Donald Trump,

after this from Twenty One Pilots.

Lucy's condition is caused by her immune system misfiring,

turning against her own body.

Seeing what happens when it goes wrong

gives us an understanding of just how powerful it is.

It's our bodies emergency response system,

ensuring we survive the many threats we encounter everyday.

Some of these defences, we're born with -

first and foremost, the skin is a protective barrier -

and others we develop as we go through life.

Cells which are able to specifically recognise and attack

foreign invaders - white blood cells, in particular,

developed in the bone marrow

and then held within the lymphatic system,

which is represented here by these green vessels.

In our final case, we'll witness what happens

when this crucial system itself comes under attack

from one of the deadliest diseases of the modern age.

One that was long thought to be completely incurable -

but a great leap forward

has come from one of the most extraordinary cases I've ever seen.

My name is Timothy Ray Brown and I'm 50 years old.

Timothy is the only person on earth

who can claim to have been cured of a devastating disease.

I used to have HIV.

In the mid-1990s, Timothy was diagnosed with HIV -

a deadly virus that attacks certain types of white blood cells,

a vital part of our immune system.

At the time, it was a death sentence...

..but research was moving quickly.

A year later, new drugs became available

that allowed him to manage his condition

and get on with his life...

I worked in a cafe at that time, in Berlin.

I was pretty honest about my being diagnosed.

Everyone knew that I was HIV positive.

..but ten years later, fortune took another turn for the worse.

I took a trip to New York,

and I felt really tired the entire time.

I thought it was jet-lag.

It wasn't jet-lag. What he actually had was leukaemia -

a cancer that affects the bone marrow

where our white blood cells are produced.

First HIV, then blood cancer.

So, how did Tim go from having to deadly diseases

to being the first person cured of HIV?

The answer lies with this doctor.

Gero Hutter treats both blood conditions and cancer.

Together, he and Tim would make medical history.

My first thought was that he was a very special patient,

because the combination of HIV and leukaemia is quite uncommon.

Dr Hutter came up with a very ambitious idea,

which he presented to Timothy,

which was, "I don't just want to cure your cancer,

"I actually want to cure your HIV."

Now, you can imagine how this would have sounded to Timothy.

I was thinking, "Yeah, right. I don't believe it."

I thought he was crazy!

But it wasn't as crazy as it sounded.

Dr Hutter knew that to treat Timothy's cancer

he would need a transplant of healthy stem cells -

the type of cells that produce white blood cells.

He also knew that a small fraction of the population, about 1%,

are naturally resistant to HIV, meaning they don't become infected.

And here's where he had a moment of genius.

If he could give Timothy a stem cell transplant

from someone who was resistant to HIV,

maybe he could cure both diseases at once.

The reason some people are naturally resistant to HIV

is because of a genetic variation in their white blood cells.

HIV is a virus that targets a type of white blood cell

known as a T-cell.

The HIV virus infects these T-cells

by attaching itself to their surface...

..but a small number of people have irregularly shaped T-cells,

which the HIV virus cannot connect to -

..so, it stays locked out...

..and, consequently, this group of people can't get HIV.

So, Dr Hutter's idea was to give Timothy a stem cell transplant

from somebody who was immune to HIV.

Finding a donor with this genetic variation

who also shared Tim's tissue type wasn't easy,

but eventually Dr Hutter secured a match.

Now, he had to carry out an extremely high risk procedure

to destroy Timothy's diseased bone marrow

and replace it with healthy bone marrow from the donor.

I was told about three years later by Gero

that his team only gave me a 5% chance of surviving that,

and I'm glad they didn't tell me that then!

Because I probably would have lost hope.

Remarkably, within just a few weeks, Timothy began to feel better.

I felt much better than I had before.

I realised that something had changed in my body.

Not only was Timothy cured of his leukaemia,

he became the first person on earth

that doctors could claim had been cured of his HIV.

At that point, I realised that, yes, in fact, I was cured,

and I was very excited about that,

and I could finally say I am cured of HIV.

So far, Timothy's remarkable experience is unique.

He and his doctors were prepared to accept the high risk

of the stem cell transplant

because his life was already in danger from leukaemia.

For others living with HIV, that risk would be too high -

but now, scientists are developing ways

to modify patients own stem cells,

so they're resistant to HIV without facing the risk of a transplant.

Their work is bringing new hope of a permanent cure.

I think what I do is I give people hope.

That is very important to me.

As I've explored these cases,

I've been struck by the vast capacity of the human body to adapt,

even when faced with the most severe threats, dangers and damage -

but perhaps the most impressive thing for me as a doctor

is how we've learned from our own bodies' ability to adapt and survive

and have used that knowledge

to develop some of the boldest life-saving treatments

in modern medicine.

Next time, we'll meet a man who woke up

and could suddenly play the piano...

..a woman who can smell disease before it happens...

It has a smell.

It definitely has a smell.

..and a man who awoke from a vegetative state

and could remember everything.