A Pinch Of Science

Mobile Phone Radiation

2011-03-31T13:45:00.000+01:00

Interesting article on radiation emissions from your mobile phone.

Flu Tip No. 1

2010-12-23T17:45:00.000Z

Hum to Clear Your Sinuses!
http://www.nytimes.com/2010/12/21/health/21really.html

In the News

2010-12-12T17:52:00.003Z

Electromagnetic Radiation from Mobile Phones:
Don't sleep with your mobile beside your bed...
http://www.nytimes.com/2010/11/14/business/14digi.html

Formaldehyde in Non-Iron Clothes:
Wash before you wear...
http://www.nytimes.com/2010/12/11/your-money/11wrinkle.html

Thinking about Food makes you want it Less:
Think about eating chocolate frequently and you won't want it so much! Useful advice at Christmas time...
http://www.bbc.co.uk/news/health-11962588

The Cat & The Cream

2010-11-12T11:55:00.002Z

Next time your moggy is lapping up his bowl of milk, take a closer look. Cat-owner Dr Roman Stocker has shown that a cat's lap is perfectly timed to maximise the amount of fluid intake without splashing and making a mess. The cat's tongue just touches the surface of the liquid, inertia creates a column of fluid that flows towards the cat's mouth and the cat closes its jaws, just in the nick of time, before gravity causes the fluid to collapse back into the bowl. Other big cats also drink in the same way. Dogs, apparently, are a lot sloppier and Dr Stocker speculates that the cats' more refined methods may be due to their dislike of water, and the fact that their nose and whiskers are extremely sensitive.

Babies also lap when cup-fed milk as newborns. New mothers trying this method are told to tilt the cup of milk towards the babies mouth and watch their tongue move forward to lap up milk like a cat. Whether they employ the sophisticated biomechanics used by cats is another matter. But then again I wonder if newborn kittens use this method instinctively (once they've passed the suckling stage) or whether they learn it over time. Must ask Dr Stocker...

How To Fight A Cold

2010-11-08T12:45:00.008Z

Some scientists at the MRC have turned science on its head. They've shown that antibodies can act inside the cell as well as externally - something new for the textbooks.

These researchers discovered that a cytosolic protein called TRIM21, is also a highly specific IgG receptor, suggesting that it could bind antibodies inside the cell. Perceived wisdom dictates that antibodies latch onto and cause the destruction of foreign bodies outside of the cell, so this was quite an odd finding. However, this research has shown that while antibodies can coat viruses outside of the cell, when the virus is internalised, TRIM21 recognises these antibody-coated viruses and triggers their degradation via the proteasome before the virus has a chance to do any damage.

See this excellent animation for further details:
http://www.bbc.co.uk/news/health-11672919

The scientists in this research used adenovirus in their experiments but speculate that TRIM21 could act against other non-enveloped viruses. Hence why everyone is getting excited about this - it could mean a new way to treat viral infections, not least the common cold and that winter bugger - norovirus.

However, if you can't wait for new drug developments, there's a more low tech approach that you can take. A report showed that people who exercised regularly were less prone to developing colds. And there's even better news if you're a bit lazy like me, those who felt fit were also less likely to develop colds and had less severe symptoms. I feel a Garfield moment coming on: Think fit! Think fit! Think fit!

'Tis the Season to be Vomiting...

2008-10-29T20:45:00.036Z

Yes, it's that time of year again, when people stop to vomit in the street, children tell tales of their friends throwing up in the playground, and hospitals contact the newspapers to tell people to stay away if they are feeling ill. Last winter it seemed that norovirus, also known as the 'winter vomiting virus' was everywhere and infecting everyone. Let's hope this year isn't the same.

In fact norovirus can occur all year round and is the most common cause of gastroenteritis (stomach bugs). It was originally called Norwalk-like virus as it was first identified after an outbreak at a school in Norwalk, Ohio in 1968. The virus was later characterised in 1972 from stored faecal samples. It is highly contagious and is thought to result in over 267 million annual infections worldwide. The GII.4 subtype of norovirus is thought to be responsible for approximately 80% of all infections. In the UK, the Health Protection Agency estimates that norovirus affects between 600,000 and 1 million people each year. In the USA, the Centre for Disease Control estimates that 23 million cases of acute gastroenteritis are due to norovirus infection. It is also thought to be responsible for at least 50% of all food-borne outbreaks of gastroenteritis. Infection is primarily through the faecal-oral route, either by consumption of contaminated food or water, or by direct contact with an infected person. Infection occurs when the virus enters through the gastrointestinal system not the respiratory system.

Apparently norovirus is very difficult to culture in the laboratory so researchers have to resort to human studies to investigate its infectious nature. A recent study was carried out by a team of researchers from Baylor College of Medicine, Texas. They published a study in October 2008 where they infected 16 volunteers with norovirus. The faeces of these volunteers were then analysed over a period of 2 months to determine the extent of virus shedding. These volunteers were chosen because they were secretor-positive which essentially means that their ABO blood group can be determined from their saliva. Secretor-negative individuals (approx. 30% of the population) are known to be resistant to norovirus infection. It is also thought that people with blood group O are most susceptible to infection, while those having blood type B show most resistance to infection and symptomatic disease. However our resistance to infection by norovirus is complicated by the fact that it is known to be continually evolving and changing its outer coat to avoid destruction by our immune system, as does the influenza virus. Most people don't achieve long-term immunity to the virus and repeated infections are common.

So back to the study, each of these 16 mugs - sorry volunteers!- were given a low or high dose of norovirus, then they were monitored for signs of gastroenteritis. This was defined as illness with moderate diarrhoea (alone) for any continuous 24-hour period or 1 vomiting episode plus 1 of the following: abdominal cramps or pain, nausea, bloating, loose faeces, fever, myalgia (muscle pain) or headache. Of the 16 people, 11 developed gastroenteritis. The other 5 did not meet the clinical definition of gastroenteritis as they didn't have vomiting or diarrhoea but developed 3 or more of the following symptoms - malaise, loss of appetite, abdominal cramps, headache, myalgia, fever, chills. The severity of illness was not determined by the initial dose of the virus and the virus was detected in the faeces anytime from 18-110 hours after the initial innoculation. In other words, it could take up to 4 and a half days for the illness to develop. Symptoms lasted from 2-4 days.

The most fascinating result of this study was that in 4 of the 11 cases with gastroenteritis the virus was still being shed in their faeces 48-56 days after initial infection. Another 4 were still excreting the virus for up to 30 days but monitoring was stopped at this point. For the remaining 3 (out of 11) the virus was shed up to 10, 15 and 21 days later. In the second group that had symptoms but not clinical gastroenteritis, 2 were monitored up to days 21 and 32 and were still shedding virus. The other 3 stopped excreting virus at days 13, 20 and 28.

From these results it is clear why norovirus has to capacity to spread to epidemic proportions. It is incredible that almost 2 months after infection some of the subjects were still shedding the virus in their faeces. Even people who did not have a serious illness were still shedding and possibly infectious for up to a month after initial infection. In fact when you read the report that 1 in 4 commuters has bacteria from faeces on their hands, is it any wonder that diseases like this spread like wild-fire in the community? Good old-fashioned hand-washing is still the most effective way of keeping germs at bay - it just seems that we're not very good at it.

So what can you do if there is a norovirus outbreak near you?

Follow the six steps listed here to reduce your chances of infection.
Read this FSA leaflet for guidance on how to deal with norovirus.
Support and promote Global Handwashing Day

A Pinch of News

2008-10-19T20:31:00.008+01:00

Interesting science in the news:

Virgin shark got pregnant in Virginia aquarium (Reuters). This is the interesting story of parthogenesis or 'virgin birth' in a shark.

Man 'roused from a coma' by a magnetic field (New Scientist). The editorial accompanying this article is only partially available online. It raises the ethical dilemma that accompanies this kind of awakening. Once a patient is raised from a vegetative state to a minimally conscious one, a brain imaging study has shown that their response to pain is similar to that of a healthy person. They can also react to voices and it is thought that they may be capable of experiencing emotions. A person in a vegetative state does not respond in the same way.

UV light fear over 'green' bulbs (BBC News). A warning not to get too close to unencapsulated (where the coil is visible) low-energy light bulbs.

Common fibre a true 'superfood' (BBC News). Pectin, a fibre found in many types of fruit and vegetables is found to fight disesase. No need to buy expensive blueberries!

Gene scan to predict hair loss (BBC News). It's not just your mother's fault if you're bald.

Internet use good for the brain (BBC News). Read this blog and boost your brain power!

So Where is all the Bisphenol A?

2008-10-12T21:22:00.030+01:00

It was the news reporter carrying an armful of plastic that made me sit up and take notice. She was talking about a recent study into the hazards of Bisphenol A but was carrying plastic bottles and containers that we used on a day-to-day basis. I decided to check it out further...

Bisphenol A (BPA) is used to make polycarbonate plastic, a clear and shatterproof plastic - baby bottles, contact lenses, lenses for glasses, CD cases, tupperware, toys are all made out of this type of plastic. It's also used to make epoxy resins which are found in paint, metal coatings and glue. It provides a protective lining found in most food and drink aluminium cans, it's used in dental fillings and to line water pipes. Global BPA consumption has increased by 10% per year since 2003; at present approximately 3 million tonnes of it is used worldwide and demand is expected to exceed 5.5 million tonnes by 2011.

So BPA is all around us and in us. Last year a study in the US detected BPA in the urine of 93% of people tested, aged 6 years and older, with children having the highest levels. A recent study has shown that baby bottles leach high levels of BPA when filled with hot or boiling liquid. BPA is also known to leach from the lining of canned food and drink. It is the levels in infants and children that are most worrying, as through their food and drink they are thought to consume the largest amounts of BPA, up to 10 times that of adults.

So why should we be worried? BPA is known to disrupt the endocrine system, in part because it mimics the hormone oestrogen. In animal and cell culture studies this leads to a whole array of adverse effects. A report published last year reviewed all of the available research on BPA. It concluded that there was strong evidence from animal and cell culture studies, that even at low levels, BPA has adverse developmental effects on the brain and behaviour, on metabolic processes and on the male reproductive tract. There was also some evidence to suggest unfavourable effects on the female reproductive tract and on the adult immune system.

In spite of this the US Food and Drug administration (FDA) and the European Food Safety Authority have chosen not to alter their guidelines and have declared that high BPA levels are safe. However the US National Toxicology Program (NTP) have issued new guidelines expressing concern over some of its effects. Just this week, 3 states in the US have written to manufacturers to ask them to voluntarily remove this chemical from baby bottles. While Canada has declared BPA a toxic chemical requiring aggressive action to limit human and environmental exposure.

So back to the news reporter - what was the latest scare associated with BPA? A team of researchers from the UK and the US analysed BPA concentrations in the urine of adults. They found that those with high BPA levels were more likely to suffer from heart disease, diabetes and have abnormal liver enzymes. You can listen to Dr Lang, the lead researcher, talking about the significance of their results.

Searching around our home, I've identified that most of the plastic we use is labelled with the recycling codes 1, 2 or 5 (see the triangle at the bottom of the container/bottle). These do not contain BPA. Polycarbonate plastic, where it's labelled, is usually identified by the recycling code number 7 - although this may include other types of plastic too. The letters PC next to the 7 is a definite indicator of polycarbonate plastic. I didn't find any number 7 plastic in our house.

On the other hand we have a cupboard full of tins of beans, tomatoes etc. that most certainly have BPA in their lining. In fact, I'm most likely looking through polycarbonate plastic as I type, even though my glasses aren't labelled with the number 7! The reality is most BPA in our homes and environment is hidden. Perhaps the biggest thing we can do as consumers is to campaign for clear labelling so that we know what we're buying. In the meantime, it makes sense to follow the NTP guidelines for cutting down our exposure to BPA, and watch out for more studies into the health effects of this ubiquitous chemical.

Update 2010:
The FDA has finally sat up and taken notice of the risks involved with using Bisphenol A; read this interesting article in the NewYork Times.

Also watch out for those till receipts! They contain 1% BPA.

Podcast describing how BPA and Triclosan (widely used anti-bacterial compound in soaps, toothpaste, cleaning materials) adversely affect the immune system.

Mmm Acrylamide...

2008-10-01T21:36:00.003+01:00

I was pregnant the first time I became aware of the hazards of acrylamide. Morning sickness meant that I couldn't tolerate a lot of foods that I had previously loved. The normally enticing aromas from things like pesto and coffee were ampilified to such an extent that I could only look at or eat the most boring and bland of foods. My daily diet was reduced to toast, cream crackers, butter puffs, rich tea biscuits and water. Anything else was sure to send me retching to the bathroom. A diet not only rich in carbohydrate but acrylamide too.

I managed to push the issue of acrylamide to the back of my mind for the rest of my pregnancy and in fact for the next few years. Really I should have known better. I was aware from my days working in a lab that acrylamide was toxic. Anyone ingesting it would first, have been rushed to hospital and second, if still alive, would have been sent for a psychiatric evaluation! Yet here I was, happily chomping down acrylamide on a daily basis and worse still, feeding it to my children.

However, in the last month or so, acrylamide has reared it's ugly head once again, and this time I've started to take notice and more importantly take action. Apparently, while I was burying my head in the sand, researchers in the Netherlands had discovered that women who consumed on average 40 micrograms of acrylamide per day were at greater risk of developing endometrial and ovarian cancer. The same group also reported a link between high dietary acrylamide and renal cell cancer. Acrylamide was already known to cause cancer in animals and these studies have demonstrated a definite risk to humans too. When we ingest acrylamide, it is converted in glycidamide and this in turn is a mutagen which can cause damage to our DNA, thus turning healthy cells into cancerous ones. A recent study has shown that acrylamide and glycidamide can cross the placenta.

The problem with acrylamide is that it's present in many of my favourite foods. It's also very difficult to eradicate. Any plant-based foods like bread and potatoes that have been heated above 120 oC will contain acrylamide. Baking, roasting, microwaving and especially frying, all result in the its formation. During this type of cooking the Maillard reaction leads to the nice brown colour that signals to us that our food is cooked. Unfortunately, the browner your food the more acrylamide that's present. It's thought that sugars present in the food react with an amino acid called asparagine resulting in the formation of acrylamide. Boiling seems to be the only method of cooking that does not raise acrylamide levels.

In September this year, the Food Standards Agency (FSA) published a survey of acrylamide along with other process contaminants in our food. The results make quite frightening reading. Crisps, potato-based snacks, vegetable crisps, dark rye crispbread and ginger nut biscuits were some of the worst offenders at over 1000 micrograms/kg. Then chips, biscuits including baby rusks, crackers, prune juice, breakfast cereals, coffee (not brewed) had in the region of 100-500 micrograms/kg. The level in bread was much lower approx 30 micrograms/kg, however these levels are increased (x10) by toasting. To put things in perspective - a daily intake of 40 micrograms was the level mentioned by the Dutch researchers and from the FSA data we can estimate that there's 48 micrograms in a 30gram packet of Hula hoops, or 24 micrograms in 30grams of Pringles, or 40 micrograms in 2-3 dark rye Ryvita crackers. So just one packet of Hula hoops a day could double a woman's risk of developing ovarian or endometrial cancer!

According to the FSA report, experts advise that exposure to acrylamide should be as low as reasonably practicable. In other words we should eat as little of it as possible. So I have decided that we as a family are going to cut down on acrylamide and here's how:

Crisps, potato-based snacks, oven chips, crackers, ginger nuts, breakfast cereal are off the shopping list and will be avoided whenever possible.
We'll buy bread that's baked in the traditional slow way which allows the yeast to act for a longer period of time than in the industrial rapid processes. The action of the yeast lowers the levels of acrylamide - so no more supermarket bread. We'll also try to eat less toast.
Potatoes will be stored at room temperature, if stored in the fridge the levels of acrylamide are higher after cooking.

Other tips for reducing acrylamide are:

Chips soaked for 30 mins before cooking apparently contain lower acrylamide, but only if you remember to cook them just to a light golden colour.
Rosemary is known to decrease acrylamide levels in food, so it's worth bearing in mind if baking bread
In industry they're experimenting with an enzyme called asparaginase to reduce the amount of asparagine in food, thus reducing acrylamide production during the cooking process.
They're also investigating adding sulphur to the soil to reduce asparagine content in crops grown which in turn would lower acrylamide in the final cooked product.

Our lifetime risk of developing cancer is increasing with every generation - at present 1 in 3 of us will develop cancer at some point in our lives. So it's worth paying attention to the level of acrylamide in food. It's probably unrealistic to say eliminate it completely from your diet but make informed food choices and eat acrylamide in moderation as part of a healthy diet.

Other webites of Interest
FSA Q&A
US Food and Drug Administration (FDA) Q&A
US FDA Food Survey (Ahh! Peanut butter chocolate, cocoa and olives all contain significant levels!) Review on carcinogenicity of acrylamide (Table I shows acrylamide content of various foods)