Stepping back in time

Our extinct ancestors walked just like us, according to American scientists. By studying ancient fossilised tracks the researchers found that our way of walking, on two feet and taking long strides with each step, evolved long before we did.

Spot the ancestral gait... Image: Raichlen et al/PLOSone

Ancient hominims – the group of primates including ourselves – could have walked in one of two ways; either they walked just like us, with long, striding steps, or with bent legs like a chimpanzee. Different gaits leave different shaped footprints, so the researchers could compare fossilised trackways at Laetoli, Tanzania, to the footprints left by modern volunteers to see how some of our ancestors moved.

The fossil footprints found at Laetoli in Tanzania have courted controversy ever since they were discovered thirty years ago. At 3.6 million years old, the tracks are the oldest direct fossil evidence of bipedalism in any of our ancestors, and this presents a problem. They could only have been left by one of our distant ancestors called Australopithecus afarensis, but their skeletons suggest they used a bent-legged gait like chimps, well adapted to life in the trees.

To solve the puzzle, the researchers asked volunteers to walk through sand normally, or imitating a chimpanzee, with bent knees and back. A laser scanner mapped the footprints they left behind, and the results showed clear differences between the two gaits – bent-knee gaits leave much deeper toe-prints, for example. With this data the researchers could then look at the Laetoli tracks.

Their results were quite conclusive: Laetoli toe-prints were shallower than their heel-prints, and in the same range as our modern gait, strongly supporting the idea that they walked much like we do today. Our way of walking is the most energy efficient way to get around on two legs, so the results also suggest walking on the ground, rather than in the trees, was an important part of the Australopithecine lifestyle – an important step towards the plains-striding apes that went on to conquer the world.

Paper Reference: Raichlen DA,  Gordon AD,  Harcourt-Smith WEH,  Foster AD,  Haas WR Jr,. (2010) Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics. PLoS ONE 5(3). e9769. doi:10.1371/journal.pone.0009769

Old before your time

Why do we grow old? It’s one of the most enduring mysteries in science, but now a team of European scientists have found a certain change in some people’s DNA that gives them a biological age much older than their age in years.

Image: Carlos Lorenzo/Flickr

We already knew that our risk of developing some age-related diseases depends more on ‘biological age’ than how long we’ve been alive, so this finding could help to identify people who are at high risk of developing some age-related diseases earlier in their life.

Growing old isn’t just a matter of how many years you’ve lived. True, that gives your chronological age, but the condition of the cells that form your body gives your biological age. In particular, the DNA is each of your cells has a cap on each end called a telomere, which get shorter every time the cell divides, so giving a clue to the cell’s biological age.

In the latest study, scientists have shown how people with a particular pattern in their DNA code have much shorter telomeres than other people, so their cells seem to be much older, biologically, than you would normally expect. In fact, the genetic change seems to add around 3.6 years to a person’s biological age!

This doesn’t mean that people with the variant are doomed to suffer from age-related diseases. Scientists still don’t understand exactly how gene variants can affect something as complicated as ageing, except that it may have some effect on how a near-by gene called TERC is switched on or off. Alternatively, it could make people more susceptible to other things that increase their biological age, such as smoking, obesity or lack of exercise.

It also takes us one step closer to understanding what this ageing thing is all about.

Paper Reference: Codd, V., et al (2010) Common variants near TERC are associated with mean telomere length. Nature Genetics, published online: 7 February 2010 doi:10.1038/ng.532

Champagne is good for you (in moderation)!

A glass of champagne is a great way to kick-start the new year celebrations. It may also be a great way to kick-start that New Year’s resolution to live healthily, according to scientists from the UK and France.

A toast - to good health! Image: Flickr/Waldo Jaquith

They found that drinking two glasses of champagne can improve blood flow around the body, reduce blood pressure and reduce the risk of blood clots forming. The health-giving effects of champagne are down to the presence of polyphenols. Polyphenols – which come from the grapes the champagne is made of – stop your body from removing nitric oxide from the blood stream. Nitric oxide is a signalling molecule that causes the bands of smooth muscle around blood vessels to relax. If it stays in the blood for longer it has a greater effect – widening blood vessels even further. Wider blood vessels mean better blood flow and lower blood pressure – both very good things.

The researchers made their discovery by comparing the effects on the cardiac system of healthy volunteers of champagne and of a similarly alcoholic – but polyphenol-free – drink. The blood vessels of volunteers who drank champagne were much wider for up to eight hours afterwards; suggesting champagne gives a short-term boost to cardiac health.

Polyphenols in red wine have been associated with good cardiac health for a while. The polyphenols come from the red grapes used to make the wine: white wine contains far fewer polyphenols and does not grant the same health benefits as red. Champagne is made from red and white grapes, and so contains polyphenols in sufficient quantity to have a noticeable effect on health.

A note of caution however: the researchers don’t yet know whether regularly drinking champagne over a long period of time would have any major health benefits. Of course, drinking too much alcohol is a really unhealthy thing to do, but a couple of glasses of champagne may be just what the doctor ordered – if you can afford it!

Happy New Year!

Paper reference: Vauzour, D., Houseman, E.J., George, T.W. Corona, G., Garnotel, R., Jackson, K.J., Sellier, C., Gillery, P., Kennedy, O.B., Lovegrove, J.A., and Spencer, J.P.E.. Moderate Champagne consumption promotes an acute improvement in acute endothelial-independent vascular function in healthy human volunteers. British Journal of Nutrition, published online 30 Nov 2009. doi:10.1017/S0007114509992959

Regular gamers have rapid reactions

Many computer games require quick reactions: whether it’s negotiating a hair-pin bend or dodging the swing of a Minotaur’s axe, the faster a player can react, the better they’ll do. It also turns out that the quick reactions learned in action-heavy games carry over to real life, according to a recent study by American researchers.

Are all of those hours playing games good for you? Image: Hypothesisnow

By looking at many different studies published by others, the researchers compared the reaction times and accuracy of regular action game-players to those of novice gamers. Regular action game-players performed, on average, 11% faster on a range of tests designed to measure reaction times.

So gamers are fast, but do they gain their speed boost at the expense of accuracy? The data would suggest not. In fact, the accuracy of both regular gamers and novice gamers was almost identical, at 92.76% and 92.75%.

The researchers also carried out a simple experiment to test their findings: a group of novice gamers were asked to play action games (Unreal Tournament and Call of Duty 2, in this case) for fifty hours over eight or nine weeks. The gamers improved their reaction times by around 13% while maintaining the same level of accuracy when compared to novice gamers given The Sims to play in the same period of time.

So playing action games regularly can train gamers to react to what they see – known as visual processing – faster than non-gamers, or even when compared with gamers whose preferred games don’t rely on quick reactions. Speedy visual processing has been linked to better reasoning and judgement, so playing action games might help elderly people retain their mental agility for longer. It could even help people who have suffered brain injuries by boosting their mental performance. Unfortunately, the researchers point out that the content and difficulty of many modern games means they’re probably not suitable for therapeutic uses in young or elderly patients.

So we probably won’t ever see doctors prescribing a course of Modern Warfare 2 for elderly patients, or a few laps of the track on Colin McRae for people suffering head trauma.  For now, it’s just good to know all those hours of gaming are doing us all some good!

Robot steadies a heart surgeon’s hand

I imagine surgery is tricky at the best of times, but how can surgeons operate on a still-beating heart as its surface constantly moves and distorts under the scalpel blade? Until recently, they couldn’t; at least not while using modern minimally invasive or ‘keyhole’ surgical techniques.

The heart - always on the move. Image credit: Gray's Anatomy, 1918

Now, a new computer model of the beating heart means a surgeon can operate as though the heart is stationary, as the robotic arm wielding the scalpel can synchronise its movements to the beating of the heart.

The new technique relies on a three-dimensional image of the beating heart provided by a stereo endoscope – a tiny camera which can enter the patient alongside the robotic tools. A computer uses the live 3D image together with a new mathematical model to predict the movement of the heart.

The robotic arm can then combine the prediction with the actions made by the surgeon to make precise incisions. As the computer worries about the beating heart the surgeon can work as though the patient is perfectly still, making the surgery much easier to carry out and much less risky.

The problem the researchers faced was that the heart’s surface is rather irregular, and its shape and size change as it beats, and that means it is hard to produce an accurate model of its behaviour. The new model and 3D endoscope were designed to cope with these irregularities, making surgery easier for the surgeon, and safer for the patient.

Minimally invasive heart surgery is too risky to be used for some less serious heart surgery, despite it being much better for patients. A robotic arm that can adapt to the movement of the heart eliminates some of that risk, and could open the way for many more heart procedures to be carried out – which will improve many people’s quality of life.

Saying that, the stabilising technique has yet to be tested on a real patient, but it has performed well on other trials. It also raises the possibility of robots one day being able to operate on us without the direct intervention of a surgeon. The question is; would you trust them to?

Paper Reference: Richa, R., Poignet, P., & Liu, C., (2009). Three-dimensional Motion Tracking for Beating Heart Surgery Using a Thin-plate Spline Deformable Model. The International Journal of Robotics Research, available through OnlineFirst at: http://ijr.sagepub.com/cgi/content/abstract/0278364909356600v1

DOI: 10.1177/0278364909356600