Researchers stimulate Parkinson's Breakthrough

Scientists have stumbled upon a new way to help patients with Parkinson's to move more easily.

Writing in this week's Science, Duke University researcher Miguel Nicolelis and his colleagues have used experimental animals to show how a simple nerve stimulation technique can overcome the symptoms of the disease.

Patients with Parkinson's, which is caused by the loss of brain cells that produce the transmitter chemical dopamine, characteristically develop symptoms of slow movements and also find movements hard to initiate. The symptoms can be partially overcome with drugs including L-DOPA, which works by boosting brain dopamine levels, although the treatment tends to become less effective with time and can also cause significant side effects. In recent years scientists have been able to provide some relief to sufferers by implanting stimulating electrodes deep within the brain to increase the activity in the neural circuits that control movements. However, this surgery is highly invasive and therefore risky. Instead Nicolelis and his team took a different approach. They implanted epidural stimulators in the main sensory pathway of the spinal cord and found that animals previously paralysed by the disease showed a remarkable improvement in symptoms. "We see an almost immediate and dramatic change in the animal's ability to function," says Nicolelis. The team think that the approach, which is much simpler and safer than implanting electrodes deep in the brain, works by blocking abnormal patterns of brain activity seen in the disease. The team think that waves of nerve activity caused by the synchronous firing of many different nerve cells build up and make it very difficult for the brain's motor circuits to initiate movements. But stimulating the sensory pathways three hundred times per second disrupts these neurological oscillations resulting in Parkinsonian animals showing twenty-six times more spontaneous movement than untreated controls.

"Following stimulation the neurons desynchronise resembling the firing pattern you would see in a healthy mouse is continuously moving," says study co-author Per Petersson.

22nd Mar 2009

Omega 3 – It might be good for you, but it’s definitely bad for fish

The health benefits of eating the Omega-3 amino acids found in fish may not outweigh the cost to the oceans of our continued fishing, according to an analysis in the Canadian Medical Association Journal this week.

Dr David Jenkins argues that although some studies show that eating fish rich in Omega 3 oils can prevent heart disease and other chronic illnesses, the evidence is not hugely convincing compared to the evidence for the dramatic falls in fish stocks worldwide.

Looking at the results from many individual studies, along with meta –analyses which themselves take many studies into account; they found that there is a suggestion that higher Omega-3 consumption could lead to a 15% benefit in the prevention of cardiovascular disease.   Some of the studies they looked at found benefits in only a few situations, and follow up studies occasionally showed the benefit to have reversed 3 years later.

In contrast, the evidence for falling fish stocks and collapsing populations is as compelling as it is frightening.  Fish catches have not increased since the early 1990s, despite increased fishing effort, and the percentage of collapsed stocks has been increasing exponentially since the 1950s.

There are also socio-economic factors to consider, such as the fact that collapsed fisheries in the United States, Europe and Japan mean that these countries are increasingly relying on importing fish from developing countries.  This means that these countries either have to allow foreign fishing fleets into their waters, or export their fish to foreign markets, depriving local communities of an important source of protein.  Food security is just one contributing factor to political and social instability, and these countries often face nutrition and health challenges.

Even farming fish may not be the solution.  To farm Salmon, Blue fin Tuna or Sea Bass, you need to feed them a high-protein diet of fishmeal and fish oils – ironically, farming fish puts even more pressure on wild fish stocks, and it actually takes between 2.5-5kg of feed fish for every 1kg of farmed fish produced.

There is a potential solution – bacteria, and genetically modified yeasts and plants may be able to supply our Omega-3 needs, but these sources have not been properly investigated to determine what doses would be healthy, and cannot yet supply the demand.

The report concludes by saying:  “Until renewable sources of long-chain omega-3 fatty acids become more generally available, it would seem responsible to refrain from advocating to people in developed countries that they increase their intake of long-chain omega-3 fatty acids through fish consumption.”

Food for thought.

Ref:  David J.A. Jenkins, John L. Sievenpiper, Daniel Pauly, Ussif Rashid Sumaila, Cyril W.C. Kendall, Farley M. Mowat , Are dietary recommendations for the use of fish oils sustainable?; Canadian Medical Association Journal; March 17, 2009; 180(6); pp. 633-637

22nd Mar 2009

Sutures of the future

Sutures of the future might well be deployed by a portable ink-jet printer according to scientists in the US. University of North Carolina at Chapel Hill researcher Roger Narayan and his team, with a view to finding better ways to close wounds, have been investigating the sticking power of a collection of proteins used by marine mussels to anchor themselves to the seabed.

As anyone who has ever tried to prise a mussel off a jetty or a rock knows only too well, these proteins are extremely powerful adhesives. "They're based around the amino acid DOPA," explains Narayan, "and because they are a naturally-occurring protein mixture they are likely to be much better tolerated by the body than sutures or artificial tissue glues like cyanoacrylate (superglue) which has been used in the past but can cause toxic effects and doesn't break down in the body". But a key question is how to utilise and deploy these sticky molecules to get them into wounds or surgical sites so that they can join tissues together.

Writing in the Journal of biomedical Materials Research B, Narayan and his colleagues may have found the answer - an ink-jet printer head. This uses a vibrating piezo-electric crystal to spit out tiny droplets. The team have found that mixing small amounts of iron ions with the mixture results in a very strong glue, probably by encouraging the mussel proteins to stick to surrounding tissue rather than itself.

"You can foresee hand-held devices in the future that could spray the correct combinations of the glue mixtures onto wound surfaces," says Narayan. "The use of the inkjet technology gives you greater control over the placement of the adhesive. This helps to ensure that the tissues are joined together in just the right spot, forming a better bond leading to improved healing and less scarring."

22nd Mar 2009

Tiger Stripes As ID

New Software can identify a tiger from its pelt, helping to catch poachers out in the act.

A tiger’s stripes are unique, much like our own fingerprints, so this means that individual tigers can be identified from its colouring.

Lex Hiby, from Conservation Research Limited, has developed a software system that uses images taken by camera traps, and stitches photos together to build a three-dimensional map of the markings, all the way from the neck to the base of the tail.  This ‘map’ can not only let us identify individual animals in the wild – helping to get accurate population numbers, but can also be flattened and used to identify skins traded on the black market.  This has the added benefit of knowing where and since when the tiger was killed, helping trap poachers in the act.

It’s an accurate technique too.  From a collection of between 264 and 298 tigers, the software correctly matched 95% of images that belonged to the same animal.

The idea behind this, using pattern recognition to identify individual animals, has been used for several different species, such as grey seals, cheetahs, penguins and whale sharks.  The beauty of pattern recognition is that you do not need your photos to be uniform.  In fact, tourist photos have been used alongside those taken by researchers to show that numbers of whale sharks have increased by 1.7% over the last 12 years, according to Jason Holmberg of research organisation Ecocean.

Hiby is confident that this software could make the backbone of a central database, as he writes in this week’s biology letters:

“An image of a skin that had been taken from one of the tigers in that database could be traced within a few minutes to where and when the living animal was last recorded."  It’s a simple software solution to help in the fight to protect this endangered species.

22nd Mar 2009

Prospecting the Gravity Field

Chris - Also this week, the European Space Agency has launched the Gravity field and steady-state Ocean Circulation Explorer, or GOCE for short.  They say it’s going to bring about a whole new level of understanding of one of the Earth's most fundamental forces of nature: the gravity field. Dr Chris Hughes, from the Proudman Oceanographic Lab, is down here on Earth with us and is planning to use the data from GOCE to better understand the world’s oceans. Hello Chris. Welcome to the Naked Scientists. Tell us, what is GOCE? How does it work?

Chris H - If you imagine having six metal cubes in a box in orbit round the Earth. Because they’re all in slightly different places, in slightly different bits of the gravitational field they move differently. Ideally what you’d want to do is track them and measure the relative motion. That  tells you how the gravity field is changed from one place to another. You can’t do that because they rattle around and bounce off the walls so instead you hold them still and measure the force that you need to hold them still.

Chris - What sort of orbit is this satellite in? Is it going over the poles so the Earth is effectively turning under it and this means effectively over the course of a one month period it scans the entire of the Earth’s surface?

Chris H - That’s right. It’s not quite over the poles, it’s about 6 degrees off but it covers almost all the Earth, yes.

Chris - Why is this useful to you as an oceanographer? What can we learn by studying the Earth’s gravitational field?

Chris H - We want to know what the ocean currents are doing. We can learn an awful lot about those from sea levels, whether the sea surface is sloping or not. It’s rather like isobars on a weather map depending on which way the wind is blowing. The sea level will tell you which way the currents are going. If you want to know whether the sea’s sloped you need to know which way is up. We know it pretty well, obviously, but we don’t know it well enough. We’re talking about very small gradients: 1 in 1,000,000 is the gradient that matters. So you need to know very precisely what the gravitational field is in order to define the direction of up.

Chris - Given that the Earth is a sphere why don’t we just see gravity being uniform everywhere across the Earth’s surface?

Chris H - Because the Earth isn’t quite a sphere. Every mountain, every bump, every different mass around the Earth has its own bit of gravitational attraction towards it. If you actually look at the shape of the sea surface what you see is a whole set of wrinkles and bumps and it really looks like a map of the sea floor. Every mountain on the sea floor is pulling the water towards it. What you think of a nice smooth, round sphere is actually quite wrinkly and bumpy when you look on the very small scale.

Chris - Understanding these currents, how will this inform us about what’s going on in the oceans?

Chris H - The ocean is almost half of the climate system. It carries heat around from the equator to the poles in just the way the atmosphere does. It keeps part of the Earth warm, cools other parts and is very important for things like fisheries but also climate in Europe in particular. It’s very difficult to measure. There’s so much going on in the oceans it tends all to happen on smaller scales than it does in the atmosphere. There are fewer measurements; it’s harder to see into. We can’t measure much in the ocean from satellites. These measurements of currents are really going to give us a huge amount of new information about the basic patterns of flow in the ocean that allows us to understand how the heat gets transported around.

Chris - How long is the acquisition of the data going to take? How long before you can come back on this programme and tell us – this is what we’ve found?

Chris H - It’s going to be at least a year. It’s going to take six months or so before the whole system is celebrated and has got down to operational measurements. There’s a lot of work where the data has been collected; turning that into useful information so that we can calculate the sea level relative to the gravitational field. There may be some early results somewhere around Christmas time but it’s going to be many years  down the line before we’ve got perfect observations that we can get out of it.

Chris - That was Chris Hughes, from the Proudman Oceanographic lab. 

March 2009

Disappearing monitors - the power of polarisation

If you have ever wanted to know how to make something on your computer screen disappear then find out here. Also find out why you should use polarised sunglasses and how an LCD monitor works.

What you need

What to Do

What may Happen

If you have the correct type of sunglasses you should find that the image from the computer screen appears and disappears as you rotate the sunglasses.