Prevent diabetes with a good night's sleep

Scientists have discovered that a component of your noctural nap, known as slow wave sleep, is critical to helping the body to regulate sugar levels and stave off diabetes.

Writing in the journal PNAS, Esra Tasali and her colleagues at the University of Chicago Medical Center recruited nine healthy young volunteers and monitored their sleep. The subjects were rigged up to a monitor which played noise from a speaker whenever their brain waves showed that they had entered slow wave sleep, which is the deepest phase of sleep. The sounds were just loud enough to disrupt the subjects' sleep, but without waking them up.  This occurred about 250 times during the night for each subject and enabled the researchers to cut the amount of slow wave sleep amongst the volunteers by 90%. The effect is similar to ageing the brain by 40 years, says Tasali. "In this experiment we gave people in their 20s the sleep of someone in their 60s."

When the volunteers woke up each morning the researchers administered a small amount of glucose, intravenously, and then monitored blood sugar and insulin levels. The researchers were surprised to see that by the end of the study the volunteers had become 25% less sensitive to insulin and their glucose levels were 23% higher. The team point out that their findings might help to explain why obese and some elderly individuals develop type II diabetes. Both old age and obesity are associated with poor sleep, which could be responsible, at least in part, for triggering some of the cases of diabetes seen in these individuals.

"Our findings raise the question of whether age-related changes in sleep quality contribute to the development of these metabolic alterations," the team say.

6th Jan 2008

Gene therapy for boozing

If you’ve overindulged at the bar this festive season, you might be interested in the latest research from Professor Yedy Israel and his colleagues.  They’ve managed to develop a gene therapy that can cut long-term drinking. But the problem is that is only works if you’re a rat.

The treatment is based on the gene for aldehyde hydrogenase, called ALDH2, an enzyme that helps the body to break down alcohol.  Some people of East Asian origin have a faulty version of the ALDH2 gene which means they can’t get rid of the toxic chemicals that are produced when alcohol is broken down.  So they feel sick, get flushed and have a pounding heart after very few drinks.

The gene therapy works by injecting what’s known as an “antisense” version of the ALDH2 gene into the bloodstream, where it interferes with the normal activity of ALDH2.  This means that the enzyme can’t be produced properly, and toxic alcohol by-products build up, causing their unpleasant effects.

The researchers tested the treatment on rats that had been bred to be heavy boozers, and were also regularly fed the equivalent of strong lager.  After a single injection of the gene therapy, the treated rats cut their alcohol consumption by half, for at least a month, although it didn’t render them completely teetotal.

There has been some controversy about the safety of gene therapy, but there are currently more than a thousand clinical trials of gene therapies for various diseases taking place around the world.

But there’s a long way to go before we could see this kind of gene therapy being given to heavy drinkers here.  For example, the researchers need to find out if the antisense genes can get into the brain, or affect developing eggs and sperm.  It might also be helpful to discover if the therapy can be specifically targeted to the liver.

6th Jan 2008

Scientists dust off hurricane warning theory

Scientists at the NASA Goddard Space Flight Center in Maryland, US, may have a new tool to offer weathermen - a way to predict a bad hurricane season.

Hurricanes are "born" in the Caribbean and western Atlantic when high sea temperatures warm the overlying air sufficiently and trigger strong winds as the hot air starts to rise. But researchers William Lau and Kyu-Myong Kim wondered whether the 200 million tonnes of sand and dust blown every year into the atmosphere from the Sahara desert could have a shielding effect, cutting down the amount of sunlight hitting the sea and therefore reducing ocean temperatures and the numbers of hurricanes.

To find out they compared satellite images of dust clouds from the Sahara with sea temperatures in the summers of 2005 and 2006. In 2006 the sea temperatures were lower, no hurricanes hit the land that year, and sure enough there was a larger than average dust cloud. The effect is most marked in summer, between June and August. Before then the dust is too scarce in the atmosphere to make much difference.

The research, which is published in the journal Geophysical Research Letters, could help forecasters to predict future storms with greater accuracy. Indeed, a Colorado State University-based team that produces quarterly hurricane predictions plans to include Saharan dust figures in their weather models in future. According to the group leader Phil Klotzbach, "the dust information will be quite useful for our final seasonal forecast in August."

6th Jan 2008

Sugar pills for your ills?

A new survey of doctors in Chicago has shown that nearly half of them have given patients a placebo, or dummy treatment, at some point. Nowadays we usually think of placebos as being used in clinical trials, to compare their effect with that of a genuine treatment.

But whereas in the past doctors also used placebos to work out if a patient was really ill or just faking it, but it seems that nearly all the doctors in the survey believed that the dummy treatment might have some benefit – if only psychosomatic.

The researchers surveyed more than 200 doctors in the city, to find out if they had ever given patients placebos, and discover their attitudes towards other psychological aspects of medicine, such as alternative therapies or doctor-patient communication.

Only around one in ten of the doctors surveyed said they thought that placebos should never be used. The doctors who admitted giving placebo treatments used various terms to describe what they were offering, including "a substance that may help and will not hurt.", "it is medication,"or "it is medicine with no specific effect." Only four percent of the doctors actually said, "it is a placebo."

There is an obvious moral dilemma attached to the use of placebos.  Research has shown that they can have beneficial effects – it’s not called the placebo effect for nothing – but is it ethical to give patients a dummy treatment?  It’s clear that there is a growing interest in the connection between mind and body for both doctors and their patients, so it will be interesting to see what happens in the future.

6th Jan 2008

Pollution brain drain

Scientists in the US have found evidence to suggest that exposure to sooty traffic fumes are costing children up to 3 IQ points of intelligence.

Writing in the American Journal of Epidemiology Harvard researcher Shakira Franco Suglia studied 200 children living in Boston, US, and found that those with the highest exposure to traffic pollution performed less well on intelligence tests than their cleaner-breathing counterparts, even after taking factors such as social class into account. This puts traffic pollution on par with lead in terms of its potential to stunt a child's brain development, although the researchers aren't yet sure exactly which components of exhaust fumes are responsible.

But previous studies on animals suggests that particulates (tiny invisible particles smaller than the body's own cells) are likely to be the culprits. These can enter the bloodstream through the lungs but there is also evidence that they can penetrate into the central nervous system via the nose, travelling along the olfactory nerves that carry the sense of smell into the brain. Once there they can directly damage cells and also trigger inflammation that further injures the brain. So the possibility is not as unlikely as it sounds. Indeed studies on dogs living on the smoggy streets of Mexico City have been shown that animals exposed to the most pollution develop brain damage similar to the changes seen in humans with Alzheimer's Disease.

Now researchers need to track down what components of traffic pollution are responsible and determine how to remove them from the exhaust pipes of the millions of cars and trucks pounding the tarmac of big cities in every part of the world...so don't hold your breath. Or on second thoughts, do hold your breath!

6th Jan 2008

Brain Change for Teenage Smokers

One of the most common addictions on Earth is the addiction to cigarettes, so tobacco and nicotine addiction.  A very interesting study has been done by Professor Leslie Jacobsen, she's at Yale University School of Medicine, looking at how smoking affects the brains of teenagers.

Chris -   Hello Leslie...

Leslie -   Hello!

Chris -   Thank you for joining us on the Naked Scientists, what have you found?

Leslie -   Well we studied 67 teenagers in this group and found that the children or the teenagers who smoked, relative to those who didn't smoke actually had a decline in attention, in particular auditory attention, and at the same time had abnormalities in the structure of their brain that looked like premature developmental changes.  The reason why this intrigued us is that, in fact nicotine in tobacco smoke binds to a receptor called the nicotinic acetylcholine receptor that's very important in modulating development in both prenatal and adolescent life.

Chris -   So you can actually place the receptor for nicotine, the part of the brain it affects, at the part of the brain you're seeing changes in at this phase in a teenagers development?

Leslie -   Right.  The receptor is actually very widely present in the brain, it's all over, but we do know from research in rats, in particular by Dr Metherate at the University of California in Irvine, that nicotine can alter the normal development of parts of the brain that support auditory attention.  This is very intriguing to us because nicotine exposure during prenatal development leads to a greater risk of impairment in auditory attention and attention deficit hyperactivity disorder.  So we actually feel that these findings may show us how this may be happening at least in some children.  

Chris -   How did you actually make the discovery in the first place?

Leslie -   We first recruited teenagers who smoked and those who didn't, and interviewed the mothers of the teenagers as to whether they smoked during the pregnancy and we also obtained birth records to verify the mother's reports.  Then we tested them in a special test that looked at auditory and visual attention, and then obtained some MRI scans, which is basically taking a picture, with a very strong magnet, of the brain.  We can measure both structure and the maturation of white matter as well as blood flow linked to cognitive work, like paying attention to a task or listening carefully in the presence of distractors.

Chris -   And this showed that the children who had either been prenatally, so when their mother was pregnant, exposed to smoking or as teenagers were exposed to smoking, had a greater degree of distractability.  It was easier for them to be put off from a task that they were doing when you had some sort of auditory stimulus, some noise or something?

Leslie -   Exactly, and the effects were most pronounced when the kids were exposed both prenatally and during adolescence.

Chris -   And what about in adults, Leslie?

Leslie -   Are you asking whether it reverses during adulthood?

Chris -   Well I guess yes, because what we want to know is, a lot of people take up smoking when they're in their teenage years, do they still continue to suffer from these problems into adulthood, or do they get better, or do you not yet know that?

Leslie -   We don't specifically know that.  It's likely that stopping smoking would improve attention, I think it's worth a try.  However what we do know is that acutely when you stop you go through nicotine withdrawal, and that's very hard on attention.  So if you already have a deficit in attention and it gets worse during the first few days or weeks of stopping smoking, then I think there's even more pressure to relapse to smoking, if you follow what I'm saying.  In other words, this deficit may make it actually harder to quit.

Chris -   And you don't think that the people in your study, when they're in the brain scanner, were feeling a bit nicotine deprived and this was putting them off from doing the trial properly, because normally they would have been smoking?

Leslie -   We actually studied the smokers, we didn't ask them to stop smoking for this study and they often took a smoke break right before they took a scan.  We measured their nicotine plasma concentrations and they were very much in a stable area that was consistent with smoking.  They were not in nicotine withdrawal.

Chris -   So where are you going to take this next?

Leslie -   Well the next question I think we have here is whether we can measure changes early after pre-natal exposure.  We're working to develop a study that will recruit infants with and without exposure, look at brain structure using the MRI scanner, which is very safe, and then follow them prospectively.  The idea here is to identify what infants are affected and then of course whether we can develop therapies that will improve their attention and reduce their risk of smoking and other problems that come from inattention, like school failure.

Chris -   Well let's hope that it isn't permanent, Leslie, thank you very much.

Leslie -   My pleasure.

Chris -   That's Professor Leslie Jacobsen, she's from Yale University School of Medicine and has found that people who are exposed to nicotine, as their mother smoking for instance when they're in the womb, or as a teenager, can have consequences for the structure of their brain as they get older.

Kat -   Scary stuff.  And if your New Years resolution was to give up smoking, and it's not too late - it's never too late to give up smoking!  If you do want help with that the best thing to do is to go to your GP and they can put you in touch with the NHS stop smoking services - best way to give up.

January 2008

Levitating plastic bags

Amaze your friends by making a piece of plastic levitate using nothing more sophisticated than a party balloon.

What you need

What to Do

What may Happen

You should be able to make the plastic float above the balloon, it is quite difficult to balance but definitely possible.