Peeing on an Electric Fence

Scientists have discovered that a dye used to colour food can also help to heal spinal injuries. Writing in this week's PNAS, a team at the University of Rochester led by Maiken Nedergaard describe how a dose of Brilliant Blue G, an analogue of the food dye FD&C blue dye No. 1, can help rats with cord injuries to recover better than controls. The effect, say the team, is down to the ability of the dye to block a class of nerve transmitter receptors known as P2X7 receptors, which are present on spinal nerves and respond to chemical signals called purines, including one called ATP. Purines are released in large abundance during spinal injuries.

When they lock onto P2X7 receptors a large pore is formed on the target nerve cell which allows large amounts of calcium and other potentially toxic substances to enter and kill the cell. This contributes significantly to what is known as "secondary damage" that often follows an injury and is responsible subsequently for a significant disability. The team had previously identified a chemical capable of blocking P2X7receptors, OxATP, which had shown promise in reducing spinal cord injury but it was highly toxic to other tissues, ruling out any therapeutic role for the agent. But this prompted the team to look for other substances capable of doing the same job, leading them to Brilliant Blue G (BBG). To test its effectiveness the team subjected experimental rats to spinal cord injuries.

Some of the animals received BBG whilst others were left untreated as controls. The researchers found that the BBG-treated animals began to recover sooner than the controls and regained superior function subsequently. And when the team compared the spinal cord tissue from the animals they found that the treated rats had significantly less secondary spinal tissue loss than the controls. The team point out that given the proven safety record of BBG this strategy could make a significant contribution to the management of spinal and other central nervous system injuries. At present, they point out, steroids like methyl prednisolone are about the best that doctors can offer a spinal injury patient. Steroids have modest benefit and work by reducing inflammation at the injury site but there is a delay before they begin to work. The effect of BBG is instantaneous, say the scientists, so it could have much to offer...

In the nineteenth centuary scientists studying the weather looked at raindrop sizes, and discovered something quite interesting. There was quite a variation, most were less than 1mm across but a few were up to 5mm across, but for the same rate of rainfall the distribution was always the same.

This is strange as there are lots of ways in which rain can be created, at different heights and rates, depending on the clouds it is coming from. At the time it was thought that it was because big drops were crashing into one another and breaking apart. The problem is that there just aren't enough raindrops in the sky to crash into each other so scientists have remained confused.

Emmanuel Villermaux at Aix-Marseille University has probably worked out what is going on. There is a well known effect on fast moving droplets of diesel in an engine, where they flatten, then blow up to form a parachute shape and then pop to form smaller droplets.

This is an effect I noticed on a high speed video of our
water rockets kitchen science experiment. right at the end of this video, watch the last water droplet falling.

So they did some experiments and discovered that the distribution of droplets coming from one of these bubbles is exactly what you find in raindrops, so this may solve the century old mystery.

They have yet to see this process occurring with raindrops, put they are flying high speed cameras on planes looking for the events.

Chris - Now, also on the news this week, the Babraham Institute, which is located just outside Cambridge, has opened a new laboratory, and so we sent Ben Valsler down there to attend the opening and also find out what was going on.  He's with us to tell us a bit about it now.  Hello, Ben?

Ben -   Hello.

Chris -   So what was this new centre about?

Ben -   Well, this is the Institute's new Bioscience Support Unit.  It cost £17 million to build and a further £5 million to equip. And it contains some state-of-the-art technology, including some funky robots that I was watching.  The Babraham Institute itself researches various biological mechanisms - how they work, how they sometimes go wrong.  And this gives us some insight into things like the causes of cancer, the causes of heart disease and actually the way that we age as well.  Now this sort of research underpins development of new therapies and this new Bioscience Support Unit will not only make the research easier and more accurate and quicker but it's actually designed in such a way to be really flexible, which makes the whole thing future-proof and should secure that investment for a good while yet.  The Babraham Institute itself is funded by the BBSRC, that's the Biotechnology and Biological Sciences Research Council.  They get their money from the UK government and Lord Drayson, who's the science minister, was there to open the unit.  Twenty-two million pounds is a lot of investment especially during a financial crisis like this one but he believes that science is a priority.

Lord Drayson -   Science is vitally important to the UK, in part, because one has to ask the question, given the way in which the world is developing, given the UK's position in 2009 in that world, what are the things which the UK is going to be particularly good at?  What is it we're going to earn our living in, as a country?  And the answer to that has to be science and the commercialisation of science, in terms of innovative new products and services.  We can't succeed as a nation by competing on this, if you like, low-tech side of life.  Our contribution has to be from those areas where the intellectual contribution that the in-depth understanding that we have shown over the decades Britain is particularly good at, is our future.  So my job as Science Minister is to raise the profile of science, to make heroes out of scientists and science entrepreneurs; to get the general public, who sometimes see science as a bit of an elitist endeavour, something that is done by a group of brainy people but it doesn't really affect them; to understand that we, as a nation, have to be both scientifically literate, because science is going to be so important to our futures, but also comfortable in discussing some of the big issues in science.  And if we can do that, we can continue being a world leader in science and if we maintain our position as world leader in science, we will have probably the happy and prosperous society.

Ben -   Lord Drayson also commended the Babraham Institute for engaging local schools and the wider community because having a future-proof research facility is only any good if we have a good supply of future scientists.  He said that there's one clear way to stay competitive in science in the future...

Lord Drayson -   Continue to invest in it and maintain our focus on excellence and making sure that we're maintaining a strong pipeline of young people coming through from the schools who get excited by science at school; that science enthusiasm maintained as they're growing up, studying at science universities and coming through to be the next generation of leading scientific researchers.  If you can develop a sort of scientific approach to living life, of noticing things and asking questions: why is that like that?  Even at the most, if you like, most mundane level.

I mean, the thing that fascinating me as the science minister is that when you get to meet really brilliant scientists it's often something early in their life that they noticed which actually got them switched on to science.  The more we can get people to make that switch go on, the more likely we'll have a positive pipeline of young scientists coming to look forward and that's going to be very important to our success as a country.

Ben -   So it now seems that doing Kitchen Science experiments with your children is both fun and it's patriotic!  That was Lord Drayson at the opening of the Babraham Institute's new Bioscience Support Unit.

Chris -   It's pretty impressive you've got to talk to him.  I think it was fantastic.

Ben -   I was quite honoured though and he was really nice and he was very down to Earth.  I didn't get the impression that,  you know, he was there to see the little people at the opening, but he was very much with us, very much supporting what they were doing, very much supporting science in the UK.

Chris -   Thank you very much.  That was Ben Valsler who went down to the Babraham Institute when they opened the new facility this week. 

Chris - Well, the answer is... I was intrigued by this (and my own observations at home) enough to want to look this up because my wife had been saying to me many times - because we now have two small children, both were breast fed - that when she ate certain things, it seemed to make the children more prone to getting a belly ache and have wind than when she ate other things. I said: "Well it's nonsense. It's coming in as breast milk." And, you know, how can that be affected by what the mum eats?So I've been having a poke around and there's a paper published in 1921; WR Shannon who found that proteins which are in the mother's diet that can pass unchanged into breast milk and there's another study which was done: Killshaw and Cant. They published in the International Archives of Allergy and Applied Immunology in 1984, and they did a very thorough study. They took 29 women who are breastfeeding. They took samples of their blood and their breast milk and then gave them an egg and half a pint of cow's milk to drink.Then they took samples of both of those blood and breast milk samples again, at various intervals afterwards. They measured the levels of these proteins and they used various measures to see whether the proteins where coming through into the breast milk. And they found that after the mother ate those things, they could pick up the egg and the milk proteins intact in her blood stream between 1 and 2 hours later and it peaked in breast milk 4 and 6 hours later. So this is really interesting. It shows things that are in the mother's diet can pass unchanged through into the baby and why they say that's important is because this may be a way in which the baby's immune system gets educated against the things that it will be eating in the future. Because we know that the babies when they are first born have this very plastic immune system that needs to be programmed what it has to recognize as a friend or what it needs to recognize as a foe. So this, perhaps, is why breast feeding is so important in helping the immune system get educated like this because the things are presented in the right context at the right time.Milk is made up mostly of water, globules of fat (yellow) and lumps of caesin protein called micelles. The micelles are covered with negative charge which repels other micelles. Ã?,© Dave AnsellHelen - Can it also be a problem? I think I have heard a story about in the Arctic, in fact, that some of the Inuit women there who eat a lot of whale meat, their breast milk becomes what's classified as contaminated waste. Some of the contaminants inside the whale meat; things like the mercury that build up in those animals living in the sea comes out in her breast milk to the point that it can be measured and it might be even damaging to their offspring, which is just disastrous. The idea that the environment is so contaminated and it's getting through our own systems. Isn't there also a story about if you have a dram of whisky that it calms down the mother and the baby.Chris - Now this is definitely true.Helen - I don't think we necessarily condone that but...Chris - But the way breast milk gets made is that there are specialised cells in the breast tissue which have a very high blood flow. The blood goes pass the breast cells; the cells remove from the blood various chemicals and concentrate them in milk. So they're using chemicals that come out of the blood, water from the blood and they're making milk. Anything that dissolves well in fat can move well through the blood vessel wall through those cells and into the ducts that line the breast. So therefore drugs and other things like alcohol can end up getting concentrated in breast milk so women have to be a bit careful when they take certain drugs because they can concentrate in the breast milk. And what she says about people who eat a diet which may be contaminated, of course there's a risk but, you know, we didn't evolve to combat heavy metal poisoning. We evolved to give our children the best start in life. So, I guess, the kind of that is unfortunate side-effect but the bottom line is breast actually best for the most part.Helen - Oh yeah, absolutely, yeah..

Helen - Well, actually they don't. As far as we can see, they don't drink that much seawater at all. In fact most whales and dolphins and things like that really don't drink seawater at all. They get most of the water they need in their diet from their food because lots of fish are about 60 or 80 percent water. And you can also get lots of water from metabolism, from oxidizing fat, and they have those blubbery layers and it can actually provide them with water. So half the time, they actually keep their mouths shut, but, of course, some does get in when they're eating their food and so on. And sea otters apparently do drink quite a bit of seawater and that could possibly be because they actually eat lots of invertebrates, sea urchins or things like that. They're quite salty and high in protein which means they create lots of urea. To process that salt and urea nitrogen does take a lot of water, So they do drink lots of water and one of the keys, really it comes down to their kidneys. They've got a very different type of kidney to most land animals in that if you look at the human kidney (or most mammals have kind of a kidney-shaped kidney - a sort of single lump with various things going inside) whereas, in fact, cetaceans and seals and things have lots of little bits to their kidneys. They're very complex structures with lobes - thousands of lobes and each one of those is an individual kidney, if you like. So they are actually able to concentrate the fluids in their urine to be stronger than seawater. So they do have that ability but they don't necessarily do it all the time, which is actually quite surprising that they don't have to do that. They actually just don't have that much salt in their system in the first place.Chris - Because one thing that is very often not apparent until perhaps you read a biochemistry book or something is that metabolism itself produces a lot of water. So when you burn sugars, you release enormous amounts of water anyway. So, therefore, some animals are very good at using all that water so their obligatory need to drink is quiet low.Helen - Absolutely and they think when certain seals and sea lions actually go through long periods when they don't eat and they're very much relying on their metabolism and their blubber at that point to provide them with enough water.

Helen -  You're listening to The Naked Scientists and now it's time to join Laura Soul who's been finding out about the latest developments in technology this month, and she's been looking into the world of open source software.

Laura -   This month in technology, we're looking at open source software.  That is software that you are free to use, modify, and redistribute yourself.  At the moment, most software is proprietary, meaning it is owned by a company.  You can't change it and you have to pay to use it.  Recently, the alternative; open source software, has been becoming more popular.  If you've used internet browsers such as Firefox or Google Chrome then you've been using open source software.  I spoke to Michael Tiemann, the President of the Open Source Initiative.

Michael -   The idea of open source software was born as people began to look at the way that software developed on the internet was developed differently than software developed in proprietary commercial environments.  What people found was that programmers who shared their work and who made their work easily accessible to other people, not just to download but also to read and to modify and to understand.  That began to exhibit a degree of innovation and a degree of quality that was completely unpredicted by backers of the proprietary software model.

Laura -   So what are the advantages of using open source?

Michael -   The underlying architecture that was designed to be easy for others to work on was a superior way of building software than the traditional proprietary model which was to make things complicated to assume limited access and to assume that only the genius in the Ivory Tower would ever even want to look at the code, so why make it clear?

Laura -   It seems the proprietary software still dominates the market.  Why do you think this is?

Michael -   In the world of information technology, there are many companies who have been accused and many companies who have been adjudicated to be monopolists, and this power of monopoly, which is explained very well in the courts shows that sometimes a monopoly can literally distort free market economics.  They can bully the market to force the market to do what they want rather than what the market would freely choose if there were a choice.

Laura -   That was Michael Tiemann, President of the Open Source Initiative.  There has been news recently of a new open source operating system like Microsoft Windows or MAC OS, that's made by Google and free to download.  Don Marti, Chair of the Open Source World Conference, happening in San Francisco in August, told me what effect this would have on the market.

Don -   Where the impact is going to be is if PC manufacturers pick up on this Google Chrome OS and start putting it on computers that people can buy at their local electronics store.  If you've got a lot of Google Chrome OS being sold to end-users, well, then all the companies that are out there making the printers and webcams and scanners and every device that you might want to plug into a computer are going to say "Well, we better get some Linux compatibility on this thing."

Laura -   That was Don Marti, Chair of the Open Source World Conference.  Microsoft is probably the most well-known proprietary software company.  I spoke to Darren Strange, head of their open source engagement in UK.

Darren -   There are many advantages in a proprietary model.  There's things in terms of being able to take a holistic view of the whole platform and that enables us to deliver products that are more reliable, they are more secure and they are more consistent in many ways.  Microsoft's on a really interesting journey and I think if you look at it for the last 10 years, we've really shifted to being a lot more open to open source.  And what we're learning is to be a lot more pragmatic about understanding that we're not competing against open source as a philosophy, that's like competing against the air.  We are competing actually against products.  So we might compete against Linux.  We might compete against other products like Open Office.  But in the same way, we also learn to work with those products too, and we're profoundly optimistic about how Microsoft and the open source community can grow together for the benefit of our customers.

Laura -   That was Darren Strange from Microsoft Open Source Engagement.  Finally, Michael Tiemann explained his hopes for open source in the future.

Michael -   I envision a world where more and more companies in the technology world are able to run as largely or fully open source companies.  I think that this idea of continuous innovation is precisely what motivates people to join the open source community and I can tell you that it's very exciting to people when they realise that the machine that they boot; all of the source code that controls that machine is available for inspection.

Helen -   That was Michael Tiemann and before that Darren Strange and Don Marti, talking to Laura Soul about news of a new open source operating system, Google Chrome OS and how the world of open source software could change in the future.

Dave - Okay. The way your eye works in the first place is it has a lens at the front - a lens in the cornea. They act together to focus light onto the back of your eye. Basically, a lens is a curved piece of transparent material. The light goes slightly slower in the lens than in the air so when light hits it at an angle it will slow down and go on the corner. A perfect lens is shaped so as it focuses all of the light from one point to outside your eye to one point on the back of your retina. The problem is as things get closer and further away, you need to change the focus. You need to change the distance. The way your eye does that is by changing the shape of your lens. The problem comes if you're short-sighted or long-sighted. Then your lens isn't the right shape for the length of your eye. And you can't adjust enough to help to see things so things look fuzzy. But the smaller the iris, the smaller an area of lens which light can get through, the less it can go wrong so the less fuzzy, the less the errors are so the less fuzzy the image is. So, basically, the main thing that squinting does is it reduces the area that light can get in through in the same way if you go out on a sunny day things look less fuzzy because your iris closes down. So if you squint you should close down your eye. You let light in through less of the lens and things look less fuzzy

We're growing some chilli peppers on our window sill. Actually, my chilli plant got some fungal disease and died though or nearly died. I've managed to resuscitate it but I had to spray something on it. It's says, "Do not use on things you intend to eat," so while I saved the plant, it's now useless because I can't actually eat it. Anyway, we're growing some chilli peppers on our window sill. For ages they've been green but suddenly they're going beautiful red and yellow colours. I understand the process why most plants are green but why do the peppers turn red and yellow? What's the point in that?Helen - Actually, I'm growing my own chilli peppers too, failing too as well. So if you've got any tips on how to do it better, I'd love to hear from you. But, well if you think about it, it's kind of a two-sided question, really. First of all, why does any kind of fruit or anything that might be eaten change into a bright red colour and usually that's if it's ripe and ready to go, it's advertising itself to be eaten by a disperser. An animal of some sort is going to come along, have a nibble, eat it, take the seeds in its stomach and release them somewhere else in the faeces to help disperse this plant. That's okay if you're a nice tasty thing like a tomato. They start out green and they don't want to be eaten before they're nice and ready, before the seeds have actually developed enough. So they will later on turn to be red and there you go. That's why they turn red, but why do chillies turn red? Do they actually want to be eaten given that they're so spicy? Do animals actually like to eat chillies? Well, there's lots of theories about why chillies evolve to have such spiciness and capsaicin is the chemical that actually makes your tongue burn when you have a mouthful of chilli, and I love it as well. And a guy called Josh Tewksbury, a scientist in the University of Washington who spent a lot of his time looking into this question of how spicy chillies evolved, why they evolved. What's the purpose of them? He's been out in the Bolivian and Peruvian jungles where we think - well, sorry, the rainforest, the dry mountainous areas, actually not rainforest, where we think these chillies first evolved and he's found some really interesting things out. So, we think that it could actually be that mammals are no good at eating chillies because they actually crunch them up. They're seed predators. That's not much use to the chilli plants; their seeds get destroyed that way. But maybe birds are the ones that the chillies are trying to attract because birds usually just swallow down the seeds whole and they don't actually get affected by the chilli and they've watched to see. There are natural variations in the amount of capsaicin you get in plants within one population of chillies. They went out and looked and they saw that mammals don't like to eat the ones where there's lots of capsaicin in the plants. But birds don't mind, they would just go for any of them.Chris - I think, they actually lack the receptor that the capsaicin locks on to on the nerve fibres.Helen - Right, there you go.Chris - So they can't detect it.Helen - That as well.Chris - Because one suggestion we did have for people who keep chickens and are fed up with rats eating the chicken food is that you put loads of curry powder in with the chicken food and the chickens don't notice the curry powder because they're insensitive to the effect of capsaicin.Helen - There you go.Chris - But the rats do and the other benefit of that is that you get a sort of premarinated chicken, so when you come to eat it, it's already nice and currified.Helen - Super! Super! It's also could be that it could deters fungal attack and that in fact having more capsaicin in the chilli plants, in their seeds helps to avoid fungus coming along and destroying the seeds. Maybe it's attracting birds that's why chillies are red but we've been doing it for an awfully long time, at least 6000 B.C. we think that chillies were being cultivated.Chris - With good reason, they're fantastically tasty.And we had a comment from Judith in Northhampton who said that capsaicin powder can be used to stop things eating your chicken food. She uses the same trick to stop the squirrels in nicking her bird feed.

Chris - Well, the answer is we've actually had Tamiflu, Oseltamivir, and there's another version of that which works in the same way but is made by a rival company and that's called Relenza Zanamivir. These agents were quite carefully designed. They were processed on what's called rational drug design actually. What they do is to target a particle on the surface of a flu virus, which is called the neuraminidase. This is an enzyme that sits down on the surface of the virus. It behaves a bit like a machete and when a virus infects a cell, it tries to bud off or get away from the cell that it's grown in, and in order to do that, it needs to make sure that it doesn't get stuck on to the surface of the cell and also get stuck in any of the mucus, which is on the lining of the airway. And this enzyme cuts the virus adrift and helps it to get free. The way Tamiflu works is by blocking up that enzyme so the virus can't escape from the cell that it's been growing in and this means that it finds it much harder to spread to other cells and this effectively confines the virus to barracks. And so, the infection progresses more slowly, it doesn't infect many other people. It doesn't infect so many other cells in the same person and, therefore, the immune system has a better opportunity to try and curtail the infection a little bit.

We put this to Neil Walker, consultant dermatologist in Oxford...

Tattoos by definition are permanent marks produced on the skin by the injection of the material by a puncturing. As a dermatologist, I see a variety of tattoos, not any of those which have been applied by a so-called tattoo artist, either a professional or amateur, sober or drunk.

Occasionally, I see people who've had a black kind of tattoo, where a dye called PPD is used, which can cause nasty skin reactions. Appropriately applied henna tattoo is not a tattoo at all. Rather, it's a drying process using the paste to produce a design in the dead outer layers of the skin. The design fades as the skin regenerates and that is one of clues as to why tattoos applied by puncturing are permanent.

Our skin is continually regenerating as the outer layers or epidermis grows from basal cells at the bottom to a dead hole-y layer at the top over a period of six to eight weeks. Pigments implanted beneath the growing layer are in the dermis or supporting layer of the skin and are not removed by the natural process of skin turnover.

The body recognises pigment granules as foreign material and there are cells whose function is to remove such material by engulfing them and transporting it to the lymph glands. These cells are unable to engulf pigment granules every certain size and, therefore, the body seem to surround them at their microscopic level by a thin layer of fibrous or scar tissue. And they become permanently trapped in the dermis.

The removal process continues slowly and tattoos may fade to a degree over time with different colours fading at different rates depending on the particle size of the pigment. In summary, tattoos are permanent because pigment particles are injected under the growing layer of the skin and the body's mechanisms for dealing with foreign materials can't remove the particles over a certain size.