Month: January 2007

On the origin of chemical species

Organic chemist Dan Lednicer has provided us with a guest Sciencebase editorial. “The enormous strides that have recently been made in molecular biology hold great promise for speeding the discovery of pharmaceuticals to treat diseases that have so far been recalcitrant to drug therapy,” he explains, “and the day may well be in the offing when a majority of important new pharmaceutical products will owe their existence to carefully crafted research programs based on the increasingly detailed understanding of the molecular biology involved in the particular disease that is being addressed.

Read the full feature from Dr Lednicer here in Serendipity and Science

Sex and diabetes

Approximately half of men with diabetes suffer at least one episode of erectile dysfunction and there are several strategies available to overcome what is in those cases usually a problem of body chemistry. According to a report in the Cochrane Review of clinical trials, the well-known drugs for treating erectile dysfunction really do improve sexual satisfaction for sufferers. The report covers the three main phosphodiesterase type 5 (PDE-5) inhibitors, sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis).

According to the study side-effects, such as headache and flushing, are common, but not sufficiently adverse as to dissuade users from abandoning the drug.

The Cochrane Review draws data from eight clinical trials (totalling almost 1800 participants) in which 976 men had been given a PDE-5 inhibitor, and 741 a placebo.

‘If taken as prescribed and when no contra-indications exist, PDE-5 inhibitors provide a useful option for men with diabetes who suffer from erectile dysfunction,’ says report author Moshe Vardi of the Carmel Medical Center, in Haifa, Israel.

You can read the abstract from the report at the Cochrane Library site. For more on the origins of Viagra and the other PDE-5 that followed in its wake, check out the Sciencebase archives.

Mobile Phones and Cancer

Mobile phones and healthThe UK Times paper reported on Saturday that a leading cancer researcher Professor Lawrie Challis chairman of the government-funded mobile telecommunications health research programme believes it is time that a large-scale study into the long-term risks associated with cellphone use.

Intriguingly, health and medicine writer Caroline Richmond pointed out that just such a study was actually published just three days prior to The Times article appearing.

The abstract for this paper by STUK, Radiation and Nuclear Safety Authority, Helsinki, Finland says:

“We conducted a population-based case-control study to investigate the relationship between mobile phone use and risk of glioma among 1,522 glioma patients and 3,301 controls. We found no evidence of increased risk of glioma related to regular mobile phone use (odds ratio, OR = 0.78, 95% confidence interval, CI: 0.68, 0.91).” The study encompasses digital and analog mobile phone use lasting ten years.

More than 200,000 volunteers and £3 million ($6m) of government and phone industry money will be needed to assess long-term risks of five years or so for cancer and Parkinson’s and Alzheimer’s diseases. Challis is currently negotiating for the necessary funding.

It is odd that this news story broke so close to the publication online in International Journal of Cancer. It also makes one wonder why there seems to be such a continued “hope” among certain segments of the media to find a correlation between mobile phone use and brain cancer. Surely, there isn’t an expectation that if such a correlation were ever demonstrated that the industry would cough up compensation to the literally millions upon millions of regular, long-term mobile phone users. Moreover, if such a demonstration were published might not a similar investigation raise concerns about other electromagnetic radiation sources again, such as powerlines, computer screens, microwave ovens and most recently wireless internet connections?

What do Sciencebase readers think? Would this be £3m well spent, or shouldn’t The Times simply publish a front page story about the STUK study, so similar to the one that Challis is after, that has already been carried out, peer reviewed and published.

Plos One latest

Plos One the new OA science journal, the launch of which we announced here on January 1, seems to be building up quite a head of steam, it’s almost superheated in fact (more on that via the link). There are some rather fancy paper titles on their homepage, as I write, covering some very disparate subject areas, which is what the journal needs if it is to compete in the open market with the likes of Nature, PNAS, and Science. Among the latest, at the time of writing are:

Superheated Water

TL:DR – Superheated water is water that has been heated to above its boiling point while held under sufficiently high pressure to keep it liquid. Technically, it is at a temperature higher than its vaporization point at the absolute pressure where the temperature is measured. It is possibly to superheat liquids other than water for a range of industrial uses.

WARNING: DO NOT TRY THIS AT HOME

Put simply, superheating involves raising the temperature of a liquid, for instance, beyond its boiling point without allowing it to vaporize. This can be done by heating water in a sealed container above 100 Celsius. There is an urban myth that has done the rounds for many years that it is possible to superheat the contents of a liquid-filled cup in a microwave and trigger a geyser of fluid when you remove it and stir. Who hasn’t received the spam-mail describing the 26-year old who was severely disfigured by such an incident?

Well, there are risks associated with all cooking, and heating a liquid in a microwave for long enough will produce a boiling temperature liquid and a container surface coated with scalding hot “condensation” that could cause you to jolt and end up splashing yourself with scalding liquid.

Apparently, it happens, so be careful. However, I think it would be hard to actually “superheat” the liquid, although the guys in this video may have done just that using pure, distilled water or similar.

The liquid would have have no so-called “nucleation” points, specks of dust, particles, or whatever, even scratches inside the beaker to seed bubbles of steam. The water could very easily surpass its boiling point without actually boiling.

Like Snopes says, it is possible but takes a lot of effort to cause superheating in a normal cup under normal conditions in a microwave oven. Nevertheless, it’s not worth risking a scalding in an attempt to duplicate the above experiment with your morning coffee.

Ambiguous aspirin

AspirinTwo back-to-back papers in the well-known chemistry journal Angewandte Chemie recently could have potentially serious consequences for the pharmaceutical industry, because they reveal what the authors claim are inherent ambiguities in the crystalline forms of aspirin.

A team of scientists from Denmark, Germany, and India suggest that the recently reported form II of the ubiquitous pharmaceutical may indeed exist but the crystallographic evidence could just as readily be interpreted as being from a single crystal of form I. The findings could have implications for patent arguments over novel forms of the purportedly generic drug.

Even from the early days of crystal studies into aspirin, there were serious issues surrounding its structure. PJ Wheatley obtained the first crystal structure in 1964, but certainly not without a degree of ambiguity. “After Wheatley, Chick Wilson got very high R-factors in his neutron study of 2000,” Desiraju told SpectroscopyNOW.com, “this is what was nagging me throughout, why were these R-factors so high?” Desiraju and his colleagues suggest that the Zaworotko study does not represent much of an improvement on the precision of these earlier studies and moreover confounds attempts to define a new polymorphic form of aspirin.

Read the full story on SpectroscopyNOW.com

Antibiotics from green tea

Green tea antibioticResearchers from Slovenia have used spectroscopy to home in on the active site of an essential bacterial enzyme, DNA gyrase. They say they now understand more clearly how a compound found in green tea, EGCG, which is a health-boosting antioxidant, works to kill bacteria.

The findings should allow researchers to design new, synthetic versions of EGCG that improve on its activity without side effects.

“I think that this direction is worth pursuing,” team leader Roman Jerala told me, “EGCG besides being unpatentable is not very stable in the body and has low bioavailability but this could be improved.” In their paper, the researchers discuss several possible research directions, however Jerala concedes that he and his colleagues lack the synthetic capabilities to pursue them. “We could only go in this direction with support from other labs,” he says, “Hopefully pharmaceutical companies will consider it.”

More…

Cotton bud art conservation

Cotton Bud SamplingA simple Q tip is all it takes to grab a microscopic sample from a work of art for laboratory testing, according to Canadian analytical chemists. They’ve used the approach to sample darkening pigments from an ancient map and from a piece of modern art as proof of principle.

They then used a range of standard spectroscopic techniques to identify components of the pigments. This particular work will provide art conservators with important clues as to how to prevent further degradation of these important cultural objects, but more widely the successful demonstration of cotton bud sampling shows that analysis of artworks needn’t be invasive and destructive.

I interviewed research leader Douglas Goltz of the University of Winnipeg who told me that, “For conservators this approach gives them another tool for identifying pigments…Certainly not every museum or art gallery has immediate access to sophisticated techniques, such as XRF – this approach can be used by anyone. The Q-tip can be carried easily and then stored for later analysis of metals in the lab.”

Read on at SpectroscopyNOW.com

Parkinson and statins

New research points to a possible link between the LDL cholesterol-lowering statin drugs (HMG-CoA reductase inhibitors) and Parkinson’s disease. Such is the concern that a study involving thousands of people is planned to assess the risk, according to a report in Chemistry & Industry today.

Earlier research had hinted at a putative link between Parkinson’s disease and statins, but the latest results from a study linking low LDL cholesterol itself to PD provides the strongest evidence to date that the link could be real.

Researchers at the University of North Carolina say that patients with low LDL cholesterol levels are more than three and a half times as likely to develop Parkinson’s disease as those with higher LDL levels.

Study leader Xuemei Huang told C&I: “I am very concerned by these findings, which is why I am planning a 16000-patient prospective study to examine the possible role of statins.” Huang was quick to point out, however, that a causal link with statins had not yet been proven. Huang adds that the well-established link between PD and apoE2, a gene associated with lower LDL cholesterol, supports her theory that low LDL is the culprit in many cases of PD.

Yoav Ben-Shlomo, a professor of clinical epidemiology at the University of Bristol suggests a contrary explanation. It could be that low LDL cholesterol levels are a consequence rather than a cause of PD, he says.

Nevertheless, statins have been in common use for more than a decade and Huang worries that if proved right we will see a big surge in the number of diagnoses of PD during the next five years.

Pfizer’s statin Lipitor is the world’s best-selling drug with $12.2 billion in sales in 2005.

Libyan death sentence

On December 19, 2006 six foreign medical workers, Kristiyana Valtcheva, Nasya Nenova, Valentina Siropulo, Valya Chervenyashka, Snezhana Dimitrova and Ashraf al-Hajuj were convicted and sentenced to death by firing squad by a Libyan court.

Their crime?

The six health workers were accused of conspiring to deliberately infect 426 Libyan children with the HIV virus.

This is the second sentencing, as an earlier death sentence was overturned by the Libyan Supreme Court in 2005.

Now, Euroscience, a pressure group promoting the responsible use of science and the conduct of researchers is calling on academic and scientific organizations to protest the sentence in the hope that the convictions can be quashed.

Enric Banda, Euroscience President, stated that “It is a tragedy that children have been infected by HIV virus at a hospital in Libya, but it is against justice to accuse a group of health workers for this incident when strong scientific evidence shows that they could not be responsible for the origin of this infection.” As Sciencebase reported previously, incontrovertible evidence suggests that the infections began long before the six Bulgarian nurses and Palestinian doctor had ever entered the hospital.

Euroscience is among several organizations appealing to Libyan leader Mu’ammar al-Gaddafi to overturn the latest sentence. The European Parliament has initiated a petition, while the Belgian Foreign Minister Karel De Gucht has called on the EU to impose sanctions on Libya over the case.