David Bradley – Page 339

Anandamide Cannabinoid

There’s a heated debate underway on the NASW discussion groups about whether marijuana is addictive or not.

Deborah Frisch came up with a great comic dialogue between two dudes [has to be two if it’s dialogue, Ed.] discussing the issues and whether or not we should be talking gently about the anandamide receptor or boldly about the cannabinoid receptor in scientific circles. My cartooning colleague Peter Welleman did a great satirical cartoon to illustrate the dudish dialogue, which we reproduce with permission from Deborah and Peter on Sciencebase.

Heavy….maaaan!

How To Do Significant Figures

Some Sciencebase visitors might already be aware of the Significant Figures Blog in which I and a few others pick apart the general media for their poor understanding of errors, accuracy and precision…we’ve had lots of enquiries asking for a quick and simple crib sheet on what sig figs (or sig digs) actually are, how to work them out, and what is their significance, exactly…

So, check out the latest posting on the SF blog to find out more –

Llama Caffeine Dip Test

After another sleepless night did you ever think that your so-called caffeine-free coffee may not be all it seems. But, how could you test to make sure the manufacturer’s claim of drug-free cafe latte is based on chemical fact?

Now, US scientists have developed a simple test for caffeine that could be incorporated into a portable device for use in the home to test caffeine levels in all kinds of beverages.

“We envisioned that a simple method to measure caffeine, even in hot beverages, such as coffee, would be of value to individuals and institutions wanting to verify the absence of caffeine,” says Jack Ladenson of Washington University School of Medicine in St. Louis, “This will greatly assist individuals who wish to avoid caffeine.”

Ladenson hopes to develop a simple caffeine test in which test strips that are treated with a specific antibody will react by changing color in the presence of caffeine.

The new test will be designed to be qualitative only: It allows a person to quickly determine whether caffeine is present, but does not indicate the exact amount or concentration of caffeine. In preliminary tests using coffee and cola, an experimental version of the test effectively distinguished caffeinated versions of these products from their decaf counterparts, Ladenson says.

Ladenson’s team hope to convert their antibody-based test for caffeine into a dipstick that could be sold in supermarkets although he confesses that he has no idea when such a kit will be available to consumers or how much it will cost.

Many of us like to avoid the late-night jitters and insomnia that follow a post-prandial espresso, but there are also concerns about the impact of chronic caffeine abuse on long-term health in terms of stress levels and blood pressures. The US Food and Drug Administration also warns pregnant women not to drink caffeine-containing beverages because of the risk of spontaneous miscarriage.

Ironically, the key to the caffeine test comes from llamas and camels – pack animals that have transported caffeinated commodities such as coffee, tea and cocoa for centuries. The immune system of camelids produces antibodies that are resistant to high temperatures common to a nice cup of char or coffee.

The researchers reasoned that if they could create heat-resistant camelid antibodies that reacted to caffeine, they could potentially build a durable assay suitable for use almost anywhere. The most stable version of a caffeine-specific antibody they produced came from a llama named Very Senorita, which worked even after being heated to 90 Celsius, about the temperature of a really hot cup of coffee. Similar antibodies from mice are destroyed at 70 degrees.

The researchers publish details of their test in the journal J Agric Food Chem in June.

For a cool coffee science experiment check out our education section.

Space Junk

There’s an interesting feature article by Frank Schaefer in the latest issue of ERCIM News (No. 65, Apr 2006) all about space junk. Schaefer points out that the historic practice of abandoning spacecraft, rocket stages, and defunct satellites has led to something like 2000 tonnes of debrit accumulating in earth’s orbit. He produces a diagram showing the catalogued distribution of this junk, much of which is in the form of tiny, but incredibly fast-moving particles.

Obviously, it is a real concern for anyone sending up new equipment as these high-energy particles can rip through equipment and space-suits with rather inconvenient results.

The caption for a photo showing a piece of irreperably damaged circuitry says it all: Degradation of computer performance follwed by cease of operation shortly after encounter of the hypervelocity particle”.

Why they had to say it in such a flamboyant way, I don’t know.

Youths and Adults First for Flu?

In today’s Science magazine policy forum, Ezekiel Emanuel and Alan Wertheimer of The Clinical Center, at NIH in Bethesda, Maryland, argue that should a [bird] flu pandemic emerge, any time soon, then, they say, priority should go to people between early adolescence and middle age.

Their argument is based on the idea that every one of us should have the opportunity to live through all life stages. They suggest that this offers the best balance of the amount the person has invested in his or her life with their time left to live should this virtual disease prove closely to 100% fatal without vaccination.

Their suggestion contrasts starkly with current recommendations for vaccinating people in the event of a flu pandemic which involves prioritizing vaccination of health workers and the elderly ill at the very top and healthy people aged two through 64 at the very bottom. The pair recommend incorporating another ethical principle that focuses on ensuring safety and the provision of food and fuel. What’s most intriguing about their argument, however, is that their ethical framework is intended to be applied only to the USA and not the whole world. The Science press release pertaining to this suggestion, simply says that this “would then involve more complex issues of global rationing.”

So, what do sciencebase readers think? Who’d care to draw up the list?

Taxol to a T

Taxol is a natural product isolated from the Pacific Yew, Taxus brevifolia. The compound was isolated from the bark of that tree by Monroe Wall of the Research Triangle Institute in the 1960s. He and his colleagues were guided in their work by the discovery of in vitro activity against L1210 cancer cells.

As is customary, the individual who discovers a new natural product gets to name that compound. Wall thus naturally called this new anticancer agent taxol (tax from taxus, ol as in alcohol, small T). He used the name in his 1971 publication announcing the chemical structure.

After that, chemists working with the compound used this name, partly because its very complex structure virtually precluded using the systematic chemical name.

Probably because it was so hard to obtain it in quantity, the compound lay fallow on a shelf at NCI until the late 1980s. Interest was revived when Susan Howrwitz discovered that the drug acted by a previously unknown mechanism: in essence it freezes cell division mid-stream by stabilizing the microtubules that should wither after pulling appart the pieces of the cells-to-be. The late Matt Suffness at NCI then made a concerted effort to pursue the compound. As part of this, NCI apparently requested bids from the private sector to join in developing taxol as an antitumour drug. This was to be one of the first such joint efforts known by the acronym CRADA (Cooperative Research And Development Agreement). The proposal tendered by Bristol Myers was deemed to be superior to the others leading to the company being awarded the agreement. The rest as they say, is history.

Somewhere along the line, however, someone either forgot to register the name taxol with the USAN as the non-proprietary name for that substance or may simply have been unaware of this requiremnent. This left the door open for Bristol Meyers to acquire Taxol as a trade name allegedly via the purchase of the TradeMark of an old laxative product and to have the non-proprietary name paclitaxel accepted as the generic term of Taxol. This meant that chemists would no longer be allowed to talk of taxol generically but would have to refer to paclitaxel, unless they were talking about BM’s drug in which case that would be Taxol, with a capital T.

So what of this laxative? It was apparently produced by Continental Laboratories Ltd of London in tablet form for the physiological treatment of constipation.

Pastel Chef and Chemist

In this week’s Alchemist I vaingloriously pronounced that oncologists might soon be able to image tumours as quickly and easily as radiologists view broken bones with X-rays.

Sciencebase contributor Dan Lednicer, a retired organic chemist turned pastel chef emailed me to point out that the statement regarding the power of X-rays required qualification:

“One day this last February, I happened to fall on my side in a parking lot. The persistent pain led me to get an X-ray the next day. This showed nothing out of the ordinary. When getting dressed one morning a week later, I found that any weight on my left leg led to excruciating pain. An X-ray in the emergency room at the hospital still showed nothing. It took an MRI (I almost wrote NMR!) to show a clean brake high up on the femur.

I now sport an impressive metal rod with a couple of appurtenances down the middle of that femur. This sails through metal detectors like a breeze, as it is made of titanium.”

So, it seems. X-rays are not the gods of imaging that my flippant remark would suggest. As to why titanium does not show up on airport metal detectors would make an interesting assignment for science class. Feel free to post your thoughts…

Scientific Tools

The Sciencebase site provides access to a selection of (hopefully) useful scientific tools, including the Cheminfo acronym lookup (just checked out SEM-EDS and ICP for an upcoming spectroscopyNOW article), a DOI paper finder to help you find full research papers from those snooty and obscure numbers that crop up everywhere in the literature. There is also an access point for the IUPAC Gold Book, and a search form for sci-tech-daily review, together with various links to other external resources.

Sex and Vomeronasal Attraction

The vexing question of whether sex pheromones play a role in human sexual attraction raises its ugly head once again, this time in a posting on The Register. Most scientists would say that there is little evidence that humans rely very much on pheromones for sexual attraction directly. However, others scientists suggest that a tiny organ in the nasal cavity, the so-called vomeronasal organ (VNO), or Jacobson’s organ, can detect chemical attractants that pass between people and are not apparent to us at the thinking level. Moreover, anecdotal evidence would point to smell having a very strong effect in sex whether or not we believe it’s pheromonal or not.

The VNO definitely plays a role in the lives of other animals from cats to snakes and from elephants to mice. In humans the organ seemingly all but disappears even before birth, leaving just a few people with a tiny pit in the septum that might have some vestige of pheromonal responsiveness.

Until, we find specific chemicals that trigger sexual attraction when sniffed, in double-blind controlled tests, it is likely that for the foreseeable future there will be no genuine, working product.

Touch Wood – Short History of Viagra

Just a reminder that the Sciencebase archive of science articles is stuffed full of interesting tid-bits (to use the PC term). Among the most popular pages (attracting the most readers in other words) is the repro of a feature article I wrote some time ago for Tomorrow’s World magazine on the subject of Viagra.

Said item was illustrated with a large banana and two strategically placed apples. I was going to dig out the original paper cutting and scan it for this item, but didn’t fancy getting a search engine rude-filter slapped on the page.

The Viagra article is here.