Month: March 2006

Bird Flu Vaccine

The BBC reports today that it has been given exclusive “access” to a Belgian trial of a new bird flu vaccine.

400 volunteers signed up to receive either the new vaccine or a placebo in the randomised double-blind trial of the GlaxoSmithkline vaccine. 399 said they were doing it for humanitarian reasons, one admitted it was for the money (300 euros) and the experience. Let’s just hope the “experience” isn’t as interesting as that suffered by volunteers in another recent trial for a drug that also triggers changes in the body’s immune system.

Benzene in Soft Drinks

Benzene StructureThis is an update to my earlier posting about benzene in soda.

Today, March 31, the UK’s Food Standards Agency has published the results of an analytical survey of benzene levels in 150 soft drinks on the market in the UK. They state that contrary to fears, benzene was not detectable in the majority of products sampled.

However, four products did contain trace amounts of benzene that are above World Health Organization (WHO) guidelines for drinking water and the FSA has ordered these to be withdrawn. An FSA spokesman explained that while the levels of this potential carcinogen are very low it is prudent for the sake of public confidence that products that contain more than the WHO suggests is acceptable should not be sold.

The issue does not address the growing fear of risk that has become endemic in Western society, but once again reinforces the negative image of “chemicals” among consumers. This is despite the fact that one of the ingredients that leads to the benzene forming in such products in the first place is vitamin C!

The FSA spokesman adds that “The levels of benzene reported in this survey will only make a negligible impact on people’s overall exposure to benzene and so any additional risk to health is, therefore, likely to be minimal.” This should be considered in the much wider context of everyday benzene sources to which a lot of people are exposed on a daily basis, vehicle fuels and cigarette smoke, for instance.

The four drinks being withdrawn from supermarket shelves all list sodium benzoate and vitamin C (ascorbic acid) as ingredients and are: Co-op brand “low calorie bitter lemon”, Popstar “still sugar free lemon & lime drink”, Morrisons brand “no added sugar pineapple & grapefruit crush”, and Hyberry “High juice no added sugar blackcurrant squash”.

It is only certain batches of these products that contain benzene at levels above WHO guidelines, but the FSA is essentially presenting the drinks industry with an ultimatum that could see an end to a consumer issue that has been known about for at least fifteen years.

More information on the FSA report is available here.

Taking the P

Pnicogen. Silent “p” or sounded? The Oxford English Dictionary (OED) people just contacted me, wanting a definitive answer.

Partly because they found my Molecule of the Month on the subject at Paul May’s excellent site and suspected I was some kind of expert. Sadly I’m not, so I’ve resorted to asking a couple of contacts who might actually have a clue. I’d like it to be p’nuh but suspect the p should be silent, as in pneumatic. However, the OED entry currently claims otherwise, and my first contact agrees that it should be “p’ni”

Shikimic Acid Shortage Sorted

Some time ago I wrote about the possibility of a shikimic acid shortage and what science is doing to address the problem. Shikimic acid, you say? The starting material for the influenza drug Tamiflu, of course!

Microbial fermentation seemed to be the way forward, but now chemists have discovered that the seeds of the sweetgum fruit – gumballs – contain significant amounts of shikimic acid. The finding means manufacturers will not have to rely on seasonal supplies of the seeds of the star anise fruit.

Thomas Poon of the W.M. Keck Science Center at The Claremont Colleges in California who heads the team says, “Our work gives the hearty sweetgum tree another purpose, one that may help to alleviate the worldwide shortage of shikimic acid.” The findings, which could help increase the global supply of the drug, Poon told the annual meeting of the American Chemical Society, this week.

Shikimic acid is used to make a generic drug called oseltamivir (Tamiflu) which is used to fight many types of flu viruses. Some health experts believe that this and similar antiviral drugs could help save lives by slowing the spread of the virus in the absence of a bird flu vaccine, which is still in development.

Simulated Astronomical Magnetism

The strongest magnetic fields in the universe have been simulated on the computer by researchers in the UK and Germany. The fields, which are thousand million million times stronger than the magnetic field of the Earth are produced when two magnetised neutron stars collide. Theory suggests these fields could be the source of violent gamma-ray burst explosions.

Neutron stars have a mass similar to that of our Sun but are just 20 km across, which makes them denser than atomic nuclei. According to the theory of general relativity, two neutron stars orbiting each other will ultimately collide violently.

Daniel Price of the University of Exeter, UK and Stephan Rosswog from the International University of Bremen, Germany, revealed their simulations of this processat at the Royal Astronomical Society’s National Astronomy Meeting on 5th April and at the Ringberg-conference on Nuclear Astrophysics on the 7th April. The results are also published today in Science Express.

“It is only recently that we have the computing power available to model the collisions and take into account the effects of magnetic fields,” explains Price, “It has taken us months of nearly day and night programming to get this project running,” he adds. Everyday magnetic fields produced by domestic electrical products such as the pump in a refrigerator are about 100 Gauss, says Rosswog. The colliding neutron stars produce a field an incredible 10 million million times stronger.

In the supercomputer simulations, Price and Rosswog show that within the first millisecond of the collision, magnetic fields are produced that are stronger than any other magnetic field that is known in the Universe. The calculations are a computational challenge because they include a lot of exotic physics, including effects of high-density nuclear physics, particle physics and General Theory of Relativity. To calculate only a few milliseconds of a single collision takes several weeks on a parallel supercomputer.

Scientists have long suspected that such a collision may be at the heart of some of the brightest explosions in the Universe since the Big Bang, so-called short gamma-ray bursts. Recent detections of ‘afterglows’ of such bursts have confirmed this idea, but much of the physics behind these explosions still lies in the dark. (Boom, Boom!)

Bacchus Bucked

Anyone who enjoys a tipple, the fruit of the vine, a pint of hop-derived beverage, or a peaty distillate from the Scottish isles can no longer kid themselves that they were imbibing for the sake of their health. Previously, research had suggested that “moderate” drinking (of alcohol) might help prevent heart disease, but a new study published today demonstrates that this argument is intrinsically flawed.

Researchers from Australia, Canada, and the US have analyzed 54 studies that linked how much people drink with risk of premature death from all causes, including heart disease. Their findings suggest that many of the studies conducted on drinking and premature death made a consistent and serious error by including as “abstainers” people who had cut down or quit drinking due to declining health, frailty, medication use or disability. When such studies show a higher death rate for abstainers than for moderate drinkers, this result may reflect the poor health of some abstainers who recently quit drinking rather than indicating a protective effect for alcohol.

The team found only seven studies that included only long-term non-drinkers in the “abstainers” group. The results of the seven studies showed no reduction in risk of death among the moderate drinkers compared with abstainers. When the researchers combined the data from these studies, they showed that it was possible to perform new analyses that appeared to show a protective effect of moderate drinking–but only when they deliberately included the error of combining long-term abstainers with people who had cut down or quit drinking more recently.

The researchers publish the details in the May issue of Addiction Research and Theory, and concede that they have not disproved the notion that light drinking is good for health, because too few error-free studies have been performed. They suggest, however, that the extent to which these benefits actually translate into longer life may have been exaggerated.

“We know that older people who are light drinkers are usually healthier than their non-drinking peers,” explains team member Kaye Fillmore of the UCSF School of Nursing, “Our research suggests light drinking is a sign of good health, not necessarily its cause. Many people reduce their drinking as they get older for a variety of health reasons.”

So….it’s not good news for drinkers, but it’s not all bad. Let’s assume that the follow-up grant applications are already being written and in the meantime, mine’s a pint!

Alchemical ChemWeb

The latest chemistry news round-up from David Bradley is now available on The Alchemist.

This week, I report on a glowing reporter that can spot biological zinc, a new class of enzyme inhibitor that starves the malaria parasite of its human blood supply, and how to convert slimy waste oil into compost. We also find out what Europeans are doing to address concerns over chemical unknowns and how at least one meeting at this week’s ACS meeting is truly sweetness and light.

Visit The Alchemist to find out more.

Magnetic Resonance Legislation

An EU directive that will become UK law by 2008, could stifle cutting edge research that uses magnetic resonance imaging (MRI) to see how medical treatments are working. The new legislation restricts the amount of time MRI operators are allowed to use the equipment each day.

Speaking at the “Science and Health” meeting this evening (March 29), Professor Penny Gowland of Nottingham University explained that, ‘The guidelines that will be imposed by the directive are overcautious and based on sparse scientific evidence. MRI is non-invasive and poses no known health risks.”

She added that the MRI community is seriously worried that the new occupational safety limits will not only curb the development of new research and medical treatments that use MRI but increase the reliance on other techniques, such as X-rays and nuclear medicine that are known hazards.

MRI produces detailed images of the body using magnetic fields and radio waves. With almost 500 MRI scanners currently being used in UK hospitals, a million examinations can be performed each year. That figure is set to increase as the government has recently invested around £100 million in over 100 new scanners. However, the new EU legislation could mean countless MRI-hours go to waste.

Peter Main, director of education and science at the Institute of Physics, joint organisers of the meeting, said, ‘MRI is a revolutionary, physics-based imaging technique. The Institute together with four other scientific organisations, has written to the House of Commons Science and Technology Committee to highlight our concerns over the proposed restrictions and the effects they will have both on research into and the treatment of life-threatening diseases such as cancer. We have written to Vladimir Spidla, the commissioner for social affairs at the European Commission to call upon the Commission urgently to review this directive.’

For more MRI news check out my news column on SpectroscopyNow.com

Penggunaan Eceng Gondok

Eceng gondok

I was intrigued by a rash of searches on the Sciencebase site from people looking for the phrase “Penggunaan Eceng Gondok”. A quick Google revealed that Eceng Gondok is the water hyacinth, although “gondok” itself is actually the Indonesian word for goitre.

A scan of three Indonesian-English dictionaries then revealed that “penggunaan” means employing or using, so visitors searching for “Penggunaan Eceng Gondok” were presumably looking for mentions of the uses of water hyacinth. Now, not having much experience of this aquatic plant, I did a little more searching and found that it is a common raw material in Indonesia for making sandals and woven goods, such as table mats it seems. As ever with artisanal and traditional crafts emerging from the developing regions of the world there is an “environmental” and “eco-friendly” tag associated with this material.

Blood Group Test

red-blood-cellsA, B, AB, or O?

A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system, and some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens, that stem from one allele (or very closely linked genes), collectively form a blood group system.

The ABO system is the most important blood group system in human blood transfusion. The associated anti-A antibodies and anti-B antibodies are usually “Immunoglobulin M”, abbreviated IgM, antibodies. ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances such as food, bacteria and viruses. The “O” in ABO is often called “0” (zero/null) in other languages.

A quite literally vital question when a blood transfusion is required and normally blood type is determined using an antibody and optical examination. However, Austrian researchers at the University of Vienna have developed a novel approach that is much simpler and side-steps expensive antibodies. Their technique is based on the blood-type-specific adsorption of red blood cells (erythrocytes) on a plastic surface “embossed” on the molecular scale.

Production of the analytical chips needed for this method is a simple and inexpensive process: quartz microbalances (tiny piezoelectric quartz crystals) are coated with a wafer-thin film of polyurethane. Erythrocytes of a specific blood type in liquid are placed on a slide and stick to its surface, forming the embossing “stamp”. The polymer is cured to harden it and the cells washed off. The ebmossed plastic surface now contains a large number of tiny impressions with indentations shaped like the antigens on the surface of the blood cells.

If a sample of blood is then placed on the chip, the erythrocytes will preferentially settle into those impressions with a matching shape. The resulting increase in mass is measured with the incredibly sensitive quartz microbalance.

The shape and size of the erythrocytes are the same for all blood types, so how can they be differentiated by these indentations? ‘The outer form is not the deciding factor,’ says team leader Franz Dickert, ‘instead, it is the differences in the surfaces of the different blood types.’ There are sugar-like molecular fragments on the surface of the cells that differentiate the blood types.

‘Despite a noticeable cross-sensitivity for the other blood types, determination of the blood type by the embossed plastic films is unambiguous,’ says Dickert, ‘because the strongest sensor signal comes from the microbalance that carries the impressions corresponding to the blood type of the sample.’

Dickert and colleagues publish details of their technique in Angew Chem, 2006, 45, 2626-2629