Category: Sciencebase

A single drop of blood absorbed on to a filter paper is all that is needed for a new test for lead, based on solid sampling-graphite furnace atomic absorption spectrometry (SS-GFAAS). The minimally-invasive method would allow many more people, and children in particular, to be tested quickly and safely for exposure to lead and to facilitate follow-up industrial safety incidents involving the neurotoxic metal.

I wrote about this research over on the SpectroscopyNOW.com site, and asked team leader Martin Resano about the applications of his test in epidemiological studies. Apparently, there is already a well established approach to testing new-borns based on a filter paper test. However, he told me that the situation is very different, there is some reluctance in the clinic to adopt filter paper tests.

“Many people in the clinical community are against the filter paper test for Pb,” Resano told me, “Precisely, the goal of our work is to show that, if a suitable direct solid sampling technique such as SS-GFAAS is used (thus avoiding the tedious and contamination-prone step of digestion of the papers), it is feasible to achieve satisfactory results for Pb blood using the filter paper test.”

InChI=1/Pb/q+2

Could a drug that blocks the brain’s cannabinoid (CB1) receptors help people stop smoking without gaining weight? According to a Cochrane Systematic Review, just 20 mg of CB1 antagonist rimonabant each day helps quitters and also helps them avoid the munchies.

Smoking tobacco sends nicotine into the blood stream, and this chemical disrupts the endocannabinoid system, part of the hormonal control mechanism in the brain that controls energy balance and food intake. Over time the body alters the nature of its energy mechanism to compensate for this effect. When you quit smoking, the nicotine withdrawal disturbs this mechanism, causing withdrawal symptoms and leaving a person prone to put on weight.

Unfortunately for smokers who want to quite and stay slim, rimonabant is yet to be approved for this use in the USA or Europe.

InChI=1/C22H21Cl3N4O/c1-14-20(22(30)27-28-11-3-2-4-12-28)26-29(19-10-9-17(24)13-18(19)25)21(14)15-5-7-16(23)8-6-15/h5-10,13H,2-4,11-12H2,1H3,(H,27,30)/f/h27H

The artificial food coloring known as Red 2G (E128, in the European Union) could soon be banned because of concerns about its safety and a purported risk of cancer arising from its aniline metabolite. The European Food Safety Authority (EFSA) recently reviewed food additives and recommended this week that the maximum safe limit for this compound should be removed. It did not go as far as to ban Red 2G, but advises that the bureaucratic wing of the EU, the European Commission, should make the decision on whether or not to ban the additive from processed meats, burgers, and sausages.

The additive is already banned in Japan and other countries, and the Irish food authority has opted to ban it as a precautionary measure.

Of course, the latest results on the metabolite, aniline, were obtained in the lab by injecting mice with a huge dose of this compound and sitting back to watch the tumors grow. They really say nothing of the effects of microscopic quantities of the precursor compound added to some meat products that a person may or may not eat on a regular basis. I don’t want to defend colorants too strongly, I’d rather eat nice freshly prepared food than processed myself. That said, not everyone has that choice, but worrying about tiny quantities of a compound that will not actually be 100% metabolized to a potential carcinogen seems an overblown response. The risk pales into insignificance compared with the far greater threat to health of eating vast quantities of saturated fat and red meat, artificially dyed or otherwise.

InChI: InChI=1/C6H7N/c7-6-4-2-1-3-5-6/h1-5H,7H2

It seems to be no coincidence that tens of thousands of molecules line up to pirouette around a photochemical reaction centre, according to German researchers, given the superficial resemblance of the molecule, 4-(diisopropylamino)benzonitrile (DIABN), to a ballet dancer en pointe. They have shown, for the first time, that the ultrafast intramolecular electronic charge separation that takes place during a photochemical reaction leads to light-induced reorientation in an organic molecular crystal.

Whether or not the same will apply to other molecular crystals remains to be seen. The results appear in Phys Rev Lett and you can read David Bradley’s write-up in the latest issue of the SpectroscopyNOW X-ray ezine. This and related studies could pave the way for investigations of more complex systems including crystalline biological macromolecules.

InChI=1/C13H18N2/c1-10(2)15(11(3)4)13-7-5-12(9-14)6-8-13/h5-8,10-11H,1-4H3

Strychnine seems to be a commonly searched entry in the ChemSpider database. I am not sure whether that means there are poisoners among the users or whether it is people hoping to find out more about the recent case of a man accused of poisoning his neighbors’ dogs with a gopher bait pesticide containing strychnine. Alternatively, it could be people hoping to learn more about recent research into the unusual poses struck by dinosaur fossils.

Dinosaur fossils always seem to show the creatures “voguing”, as if there were some Jurassic equivalent of the 90s dance craze kicking off some time BC. But, the odd postures of these long-dead animals would actually suggest that they had an agonized death – the wide-open mouth, head thrown back and recurved tail – all point to poisoning, disease, or asphyxiation, according to two Berkeley paleontologists.

The usual explanation for the postures is that the dinosaurs simply died in water and currents dragged their bones into these odd positions and they were frozen in time as sediments settled and fossilization began.

Berkeley veterinarian-turned-paleontologist Cynthia Marshall Faux has seen a lot of animals that have been poisoned, hit by vehicles, or died of painful disease. They often arrive displaying the same postures as these fossils. She believes that the posturing dinosaurs may have met unnatural deaths, choking on volcanic ash, diseased, or poisoned.

The very same posture is seen in several disease states as well as in strychnine poisoning. Srtychnine is a highly bitter alkaloid found in several plant species, but it is its LD50 of approx. 10 mg per kilogram of body weight that points to its highly toxic nature. Strychnine causes muscular convulsions and eventually death through asphyxia or sheer exhaustion. Virtually all articulated fossils of Archaeopteryx have been found with the characteristic posture of the strychnine poisoned. We may never know exactly how these creatures died, but could it be that there was a dinosaur poisoner in the wild during the time of the dinosaurs?
InChI=1/C21H22N2O2/c24-18-10-16-19-13-9-17-21(6-7-22(17)11-12(13)5-8-25-16)14-3-1-2-4-15(14)23(18)20(19)21/h1-5,13,16-17,19-20H,6-11H2

Yet another possible explanation for the bias in life’s handedness – the fact that nature uses mainly only form of the building blocks of proteins – comes from Dutch chemists experimenting with the sublimation of amino acids.

Writing in the latest issue of my alma mater Chemical Communications, Ben Feringa and colleagues at the University of Groningen have demonstrated significant enantioenrichment of a variety of amino acids by sublimation in which preferential evaporation of the predominant enantiomer occurs from a mixture of low ee amino acids. They lay claim to this process as being a possible mechanism for the presence of ee of amino acids under the conditions found in space.

Theories abound as to why life on earth predominantly uses L amino acids. Most rely on some obscure initial set conditions and a convoluted route from a small excess in outer space to the seeding of amino acids on earth. While Feringa and colleagues discuss their findings in terms of interplanetary conditions it may be just as possible that their process had some counterpart on the primordial earth.

InChI=1/C6H13NO2/c1-4(2)3-5(7)6(8)9/h4-5H,3,7H2,1-2H3,(H,8,9)/f/h8H

According to a recent report in Wired, agents at the FBI labs in Quantico, Virginia, have discovered that chilled samples of urine can spontaneously produce the drug GHB (gamma butyrolactone), commonly known “liquid E” and a well-known date-rape drug involved in an increasing number of what the FBI terms “drug-facilitated sexual assaults”, or DFSA. However, certain observers suggest that the while GBH is infamous its use in DFSA is far less common than law-enforcement agencies would have us believe; alcohol is a much guiltier party in DFSA than any other substance. The findings, based on GC-MS (gas chromatography-mass spectrometry) suggest that suspects could give a false positive result even in the toughest FBI forensic test.

Writing in the journal Forensic Science International, the FBI team, lead by Marc LeBeau, explains that, “Our study suggests in vitro production of GHB may increase the apparent GHB concentrations in urine during storage. To minimize this production, it is suggested that urine specimens be maintained in a refrigerated or frozen condition and analyzed as quickly as possible. This is particularly important, because GHB analyses are relatively infrequent requests in many laboratories. Therefore, specimens are likely to be stored for some extended period of time before the analysis is carried out.”

Earlier studies had hinted at increasing concentrations of GHB, GBL, or 1,4-BD in the urine of abusers of these comppunds. “It is generally accepted that urine is the most valuable specimen in DFSA cases,” explains LeBeau, “and that 10 micrograms per milliliter be used as the cutoff concentration to differentiate between endogenous and exogenous GHB in urine.”

The FBI team admits that it does not yet know what causes increasing concentrations of GBH in urine samples. It could be microbial activity, but it is probably not straight putrefaction. “Whatever the cause of these small artificial increases in endogenous GHB [in urine samples], the modification is likely driven by time, temperature, and/or changes in pH,” they say. But, also in taking the wind out of Wired’s sails, not only is GBH not considered a date-rape drug, the FBI team adds that, “It should also be noted that none of the samples in this study ever exceeded the recommended urinary endogenous GHB cutoff of 10 micrograms per milliliter.

InChI=1/C4H6O2/c5-4-2-1-3-6-4/h1-3H2

TL:DR – Catnip, catmint is often referred to as cat crack. It is thought to have a weakly psychoactive effect in cats and sedative and euphoria-inducing effects.

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Over on the excellent Instructables site, talbotron22 (aka Logan Sandmeyer) has found a way to extract the active ingredient, nepetalactone, from catnip (Nepeta cataria, also known as catmint) and so create a product that is essentially skunk for cats. As you may or may not know, half of all cats , are overwhelmingly intrigued by the scent of catnip. No one knows quite why, but the active compound is known to be weakly psychoactive, triggering sedation and euphoria, so it could simply be that your pussy cat wants to get high.

talbotron22 suggests that the use of his concentrated catnip extract could make him something of a cat god. But, if catnip is the feline equivalent of hash, and he is cooking up some skunk, or worse still cat-crack, then doesn’t that make him some kind of pusher? Well, he does provide a safety disclaimer that should keep his name clean:

“Yes, it is safe to use this extract on cats. I have looked into it, and there are a number of studies (very interesting in their own right) using pure nepetalactone on cats in experiments trying to figure out why it causes them to go bonkers. The upshot is that it’s pretty safe. In the last of the references below, the LD50 of nepetalactone was determined to be 1550 mg/kg (about the same as aspirin), meaning you would have to force feed your average 5 kg cat ~8 grams in order to cause it any harm. So as long as you are reasonable with the extract it should pose no harm.”

Moreover, his extraction process produces very pure nepetalactone but only a small yield, even the most determined feline drug peddler would have to spend days on the project just to keep kitty happy.

InChI=1/C10H14O2/c1-6-3-4-8-7(2)5-12-10(11)9(6)8/h5-6,8-9H,3-4H2,1-2H3

Viagra could be the cure mile-high clubbers have been waiting for. Apparently, not only can the drug help men keep up appearances at any altitude, new research could lead to its extension to other areas of medicine, such as the treatment of jet lag.

Apparently, researchers in Brazil simulated jet lag in hamsters by exposing them to light out of phase with their natural body clock, giving the little beasts the feeling of having flown from Paris to New York on the red-eye day after day. The result was that the hamsters’ circadian cycle got so skewed that they would mount their wheels and run 14 hours before they should each night.

However, Diego Golombek and colleagues from the Quilmes National University in Buenos Aires, figured that a quick shot of Viagra (sildenafil citrate, sildenafil without its counter ion is shown) might work wonders for the hardy little creatures. In fact a 70 mg dose of the ED drug, reduced the jet lag recover period for the animals to just over a week, compared with the two weeks it took the Viagra-free hamsters to recover. What a relief.

Circadian clocks regulate the timing of biological functions in almost all higher organisms, say Cornell University and Dartmouth College researchers writing independently in the journal Science, this week. Anyone who has flown through several time zones knows the jet lag that can result when this timing is disrupted, they say.

Now, the Cornell and Dartmouth scientists believe they can explain the biological mechanism behind how circadian clocks sense light through a process that transfers energy from light to chemical reactions in cells. Whether or not this research tells us if you should keep your eyes closed during or after entry into the mile-high club or how to disguise why you are not suffering jet lag after a long trip is a different matter.

InChI=1/C22H30N6O4S/c1-5-7-17-19-20(27(4)25-17)22(29)24-21(23-19)16-14-15(8-9-18(16)32-6-2)33(30,31)28-12-10-26(3)11-13-28/h8-9,14H,5-7,10-13H2,1-4H3,(H,23,24,29)/f/h23H

A daily dose of aspirin could save you from a heart attack or stroke, but almost a quarter of a million Americans could be hospitalized each year because of gastric bleeding – a complications of taking the drug.

A study by cardiologists at the University of Kentucky College of Medicine, the Institut de Cardiologie-Centre Hospitalier Universitaire Pitié-Salpêtrière in Paris, France, and the UK HealthCare Linda and Jack Gill Heart Institute have found that the commonly prescribed 325 mg adult tablet is a lot more than most people will need to reduce their risk of cardiovascular disease each day. Their findings published in the Journal of the American Medical Association, suggest that an infant dose of aspirin, containing around 80 mg of the active ingredient is adequate for preventing cardiovascular events in the long-term and has the advantage of a much lower risk of gastrointestinal bleeding.

The researchers carried out a meta review of published clinical studies data on aspirin use and found no large-scale studies that supported higher doses of aspirin, even for patients with diabetes who are tougher to treat.

“While aspirin is an effective drug for the prevention of clots,” says lead author Charles Campbell, “the downside of aspirin therapy is an increased tendency for bleeding. We believe the minimum effective dose should be utilized (75-81 mg).” He cautions that this is a ballpark figure and the optimum dose should be considered on a patient by patient basis.

Aspirin is the oldest “manufactured” and most commonly used drug in the world. More than 50 million people, or 36 percent of the adult population in the United States, consume 10 to 20 billion aspirin tablets each year as a prophylactic against heart attack and stroke.

“Patients should check with their doctor to be sure, but there is almost no one who needs to take more than 81 mg of aspirin a day for protection from heart attacks,” adds co-author Steven Steinhubl.

What strikes me as odd about the press release that announced these findings is the precision in the milligram values given. A drop from 325 mg to 75-81 mg comes with unnecessary precision. that additional 1 mg is less than a third of a percent of the original mass and probably way below the weight tolerances available during the manufacturing process in the first place. Moreover, many patients are told to break a whole tablet in half and take just half a day, so any kind of precision in weight measurements is lost instantly as those tablets crumble and fragments containing perhaps several milligrams of aspirin are lost.

Also in the news this week and somewhat conflicting with Steinhubl’s recommendations is the discovery that at least 300 mg of aspirin taken daily might help prevent colorectal cancer. Peter Rothwell of the University Department of Clinical Neurology, at the Radcliffe Infirmary in Oxford, UK, suggest that the benefits of taking such a large dose of aspirin in the long term outweigh the risks associated with gastrointestinal bleeding for those at high risk, such as individuals with a strong family history of the disease or other factors. This second study is published in The Lancet today, more details in the original press release.

InChI=1/C9H8O4/c1-6(10)13-8-5-3-2-4-7(8)9(11)12/h2-5H,1H3,(H,11,12)/f/h11H