David Bradley – Page 342

Alchemical Slicing

Slicing up carbon to make a new class of electronics, caught The Alchemist’s eye first this week, and then a new class of antibiotics that slices up bacteria came to light. In this issue, we also learn how layered ceramics could build three-dimensional nano-devices and that cars produce too much carbon dioxide for environmental targets. Finally this week, designer zeolites could soon be with us thanks to a new model of the crystal growth process.

Check out The Alchemist’s discoveries on the relaunched ChemWeb site.

Bird Flu in Britain

The BBC reports this morning that about 35,000 chickens at a poultry farm in Norfolk, England, are to be culled after dead birds tested positive for a strain of bird flu. What makes this interesting is that the newsdesk subbies are now going to have cope with another strain of avian influenza – H7, as opposed to H5N1. H7N7 was, of course, responsible for an outbreak in The Netherlands where 30 million birds had to be slaughtered, but this is the first time it has reached British shores. H7 is not as great a risk to human health as H5N1, although H7N7 infected 80 people in The Netherlands. Bacteriologist Hugh Pennington of Aberdeen University, said that while the H7 strain was “nasty for the birds”, it was “not a public health threat to humans”, the BBC reports. “It’s basically a virus that kills chickens and has been around for many, many years.

So, one might ask, why did the BBC get a quote from a professor of bacteriology, rather than virology?

Defining Obesity

Following on from Wednesday’s posting on the subject of an obesity stifling pill, health professionals have been told that they need to use more than tape measures and scales to define and tackle obesity. The claim appears in the British Journal of Advanced Nursing.

Maryanne Davidson of Yale University discovered that many women fail to make the link between high weight and poor health and that culture is to blame, playing a key role in how positively they see themselves. Davidson reviewed key papers published over a 10-year period to see how health professionals and black and white American women define obesity and to identify differences in attitudes.

The study revealed that while health professionals used quantitative methods, such as Body Mass Index (BMI) measurements based on the height to weight ratio, women are more likely to base their ideal weight on cultural criteria. “My review revealed that black American participants defined obesity in positive terms, relating it to attractiveness, sexual desirability, body image, strength or goodness, self esteem and social acceptability,” Davidson says, “In addition they didn’t view obesity as cause for concern when it came to their health.”

White Americans, on the other hand, expressed completely the opposite view: “They defined obesity in negative terms, describing it as unattractive, not socially desirable, associated with negative body image and decreased self-esteem and being socially unacceptable,” explains Davidson. Worryingly, she adds, “when it came to the links between body weight and health, this group was much more likely to voice mixed views, with some expressing concern and others feeling that weight wasn’t a health issue.”

From the clinical care perspective, Davidson has also discovered that there are variations in how health professionals define obesity. “Although most of them use BMI to actually measure obesity, we found different views about what level of BMI constitutes normal weight and what level indicates obesity,” she says. Such findings provide a real challenge for healthcare professions.

People have been obsessed with their weight since records began, Davidson adds. She points out that the “Spartans” reportedly ostracised a man for being too fat and Socrates danced every day to keep his weight within reason! Such apocryphal tales tell us nothing about the health implications of being overweight today.

People see this as a genuine issue and spend a lot of money on trying to reduce their weight. Others spend time in the gym and take the healthy option while others face the risks of going under the knife. Bariatric surgery and liposuction prices are just a few of the factors that potential patients must consider.

“Obesity is a major issue for health professionals as it is emerging as a worldwide healthcare epidemic,” says Davidson, “The World Health Organization estimates that there are at least 300 million obese people worldwide and a further one billion who are overweight.”

Hormone Stifles Appetite, Fights Obesity

Researchers in the UK have discovered that topping up levels of a gut hormone could help people stave off feelings of hunger as well as increase activity in overweight and obese people.

According to research to be published in the International Journal of Obesity injections of the appetite-suppressing hormone oxyntomodulin, which is found in the lower intestine, have a “double effect” on people.

Chief researcher Steve Bloom of Imperial College London points out that, “The discovery that this hormone has a double effect, increasing energy expenditure as well as reducing food intake, could be of huge importance. When most people diet, this produces a reduction in activity, which is probably an adaptive trait to conserve energy during times of famine. However, this does make it especially difficult for obese individuals trying to loose weight. In contrast, oxyntomodulin decreases calorific intake, but actually increases energy expenditure, making it an ideal intervention for the obese.”

The research builds on Bloom’s earlier findings reported in the journal Diabetes in 2005, which were hailed as a major breakthrough in treating obesity.

Sex Gets Up Womens Noses

Spray-on sex could usher in an age of McNookie, according to an article in The Observer on Sunday. PT-141 is billed as libido in an atomiser, says the paper, and could finally offer women the chance to turn on their sexual desire as and when they need it.

“A dose of PT-141 results, in most cases, in a stirring in the loins in as little as 15 minutes,” reports Julian Dibbell, “Women, according to one set of results, feel ‘genital warmth, tingling and throbbing’, not to mention ‘a strong desire to have sex’.”

So, what is PT-141?

It’s an odourless and colourless synthetic chemical that you inhale deeply through a small, white plastic inhaler. The compound, produced by Palatin Technologies and currently undergoing regulatory assessment, is a melanocortin-based therapy that seems to work directly on the brain rather than simply stimulating the loins as is the case with Viagra.

The drug’s market name is Bremelanotide and it’s a word you’re sure to see a lot more of in the near future as spammers start offering it and variations on the theme (watch out for Bremelan0tide in your email subject lines). Its mode of action is poorly understood, but unlike thousands of years of rhino horn, tiger dick, and oysters this one definitely seems to work.

Molecular structure of Palatin's PT-141 (Bremelanotide)

“It’s not merely allowing a sexual response to take place more easily,” Michael Perelman, co-director of the Human Sexuality Program at New York Presbyterian Hospital and a sexual-medicine adviser on the PT-141 trials explains, “It may be having an effect, literally, on how we think and feel.” What is known is that it acts on at least one of five known melanocortin receptor subtypes in the brain. These are chemical receptors that regulate a diverse array of functions including sexual arousal, appetite, energy maintenance and inflammation. The company is working on drugs to affect these receptors and so help with sexual dysfunction, obesity and cachexia (disease-related muscle loss).

One has to wonder though whether the advent of drugs like PT-141 is simply another example of the kind of drug mongering I discussed a few years ago my Alchemist column on ChemWeb. There now seem to be dozens more “diseases” than there ever were. Is it just coincidence that problems that were not considered problems are now categorised as syndromes and disorders have emerged at just the time when the patents are expiring on the billion dollar staples of the pharmaceutical industry? Maybe, maybe not. Some of those disorders, such as restless legs syndrome, may sound like spurious ailments invented by a desperate industry, but they certainly aren’t for those who suffer from them. Even shyness and anxiety might one day succumb to drugs, and why not? If these disorders are debilitating then who are we to suggest that sufferers have no right to a treatment that “cures” them?

Sometimes there is no relief for a whole range of problems without pharmaceutical intervention. Whether or not we should allow people the option to control their sexual desire chemically is a moot point, the fact is humans have used all kinds of methods to loosen up a libido for millennia, and will continue to do so whether that’s with a regulated drug or something else. Palatin seems simply to be hoping to take a slice out of the action.

Anyway, for those interested in such things Palatin gives the basic structure of its product as a short cyclic peptide with the sequence – Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. It’s currently in Phase III clinical trials, so it shouldn’t be too long before those spams start arriving.

Black Cohosh and Hot Flashes

black cohosh menopause remedy According to news just in from the American Chemical Society, millions of women use the herb black cohosh (Cimicifuga racemosa) as a dietary supplement to help treat hot flashes and other menopausal symptoms. However, there are no definitive clinical trials to say whether they are wasting their money or not. Some studies report that black cohosh helps relieve menopausal symptoms such as hot flashes, while others do not.

A new study to be published May 17 in the Journal of Agricultural & Food Chemistry reveals that many of the black cohosh supplements sold across the US actually do not contain any of this plant at all. Rather, they are formulated with a related plant species that has none of the same chemical compounds or clinical applications as the native North American plant.

Edward Kennelly, Fredi Kronenberg and colleagues report that a new analytical technique, allowed them to quickly test 11 products on the market claiming to contain black cohosh. Three contained an inactive adulterant, and one contained both genuine black cohosh and an Asian imitator. Products containing only black cohosh varied significantly in the amounts of the compounds believed to relieve menopausal symptoms.

“In the US, botanical dietary supplements are regulated as foods, rather than drugs,” noted Kennelly, “The manufacturers are required to follow good manufacturing practices, so this misbranding should not occur. Unfortunately, our study shows that at least in the case of black cohosh, many manufacturers are not following the regulations.”

In other words, caveat emptor applies as always, adds Kennedy: “Consumers should be aware of this situation in order to make proper choices for their health care.”

Natural Spinoffs

Writing on the CHMINF-l discussion group, Buffalo U librarian A. Ben Wagner explains how he has come to an agreement with faculty to draw a line under subscribing to new spinoff publications of the journal Nature. “no sooner had reluctantly subscribed to Nature Physics partly under the justification that at least this time they had picked a major discipline,” he says, “only to find
out in a few months they are bringing out Nature Nanotechnology and Nature Photonics within months of Nature Physics.”

Here’s the list of spinoffs Wagner cites together with first publication date (Nature Biotechnology was a new incarnation of the journal Bio/Technology)

Nature 1869, Nature Biotechnology 1983, Nature Genetics 1992, Nature Structural & Mol. Biology 1994, Nature Medicine 1995, Nature, Neuroscience 1998, Nature Cell Biology 1999, Nature Immunology 2000, Nature Reviews. Genetics 2000, Nature Reviews. Molecular Cell Biology 2000, Nature Reviews., Neuroscience 2000, Nature Reviews. Cancer 2001, Nature Reviews. Immunology 2001, Nature Materials 2002, Nature Reviews. Drug Disc. 2002, Nature Reviews. Microbiology 2003, Nature Clinical Practice Cardiovascular Medicine 2004, Nature Clinical Practice Gastroenterology & Hepatology 2004, Nature Clinical Practice Oncology 2004, Nature Clinical Practice Urology 2004, Nature Methods 2004, Nature Chemical Biology 2005, Nature Physics 2005, Nature Clinical Practice Endocrinology & Metabolism 2006, Nature Clinical Practice, Nephrology 2006, Nature Clinical Practice, Neurology 2006, Nature Clinical Practice Rheumatology 2006, Nature, Nanotechnology Oct. 2006, Nature Photonics Jan. 2007

“Even the Rocky movies only went to 5!” Wagner said. But, isn’t this just what every other academic publisher is doing, new journals seem to appear one after the other regardless of whether it’s a commercial, learned society, or open access publisher? Robert Michaelson of Northwestern U added that “Libraries and universities – especially faculty – need to stand up to “The New Elsevier”, which is displaying the avarice of the original model.” Dana Roth of Caltech also pointed out that Nature Protocols (putatively online only) is also on the horizon as is Nature Chemistry.

Michaelson also asks, “Is there really a need for Nature Physics, or Nature Nanotechnology? Certainly there isn’t a need in the scholarly community – all of the papers published in these titles could easily be published, at far less cost, in existing well-established journals.”

Presumably, Nature Publishing Group has a different spin on this and is addressing what it sees as a market need as increasingly multidisciplinary endeavour requires new outlets as the traditional boundaries between old disciplines become increasingly blurred.

That said, a follow up posting from UCR’s Chris Reed provocatively suggested that librarians and faculty should be proactive in stamping out this proliferation of journals, singling out not just NPG but citing Bentham as particularly aggressive in this area. “I have also recommended that the best way to change faculty habits is to pay them,” he said on the list, “Overpriced journals should be cancelled and some of the saved money given to Departments whose faculty agree not to submit to, referee for, accept editorial board appointments on journals they decide are too exploitive.”

Natural Born Painkillers

According to a press release I only just spotted from the journal “The Cochrane Library, a randomised controlled trials has demonstrated that extracts of Devils Claw (Harpagophytum procumbens), White Willow Bark (Salix alba) and Cayenne (Capsicum frutescens) all reduce low-back pain better than placebo. Devils’ Claw and White Willow Bark also compare well with conventional medicines, claim researchers in a a systematic review published in Issue 2 of the journal this week.

Devils’ Claw is apparently well known for its anti-inflammatory and analgesic qualities and purportedly can reduce pain to the same degree Vioxx (well anything can beat Vioxx these days, surely, seeing as it’s a banned medication). But, that aside, it’s the seeming surprise in finding that S. alba can relieve pain. An extract of cricket bat willow was the very product that kick-started the pharmaceutical industry when German manufacturer Bayer branded a modified version of the active component, acetylsalicylic acid, as aspirin.

There is no mention of this in the press release, but it’s unlikely that the papers authors were totally unaware of the natural evolution of this compound.

Surely.

Russian Chemical Bulletin

Several Sciencebase visitors have been trying to locate the Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science, a chemistry journal coming out of, you guessed it, Russia. Well, according to the Springer Publishers website this journal is now known as Russian Chemical Bulletin and can be found here.

The journal is edited by well-known Russian chemist O.M. Nefedov and publishes some 500 original, peer reviewed papers a year in the fields of General and Inorganic Chemistry, Physical Chemistry, Organic Chemistry, Organometallic Chemistry, Chemistry of Natural Compounds and Bioorganic Chemistry. So, now you know.

Carbon Nanosheets

Andre Geim of the University of Manchester and his colleagues reckon graphite, the slippery soft allotrope of carbon, could lead to a new generation of microelectronic devices. Geim and colleagues laid out graphite sheets one layer at a time to allow them to study the properties of these graphene sheets.

A graphene sheet is electrically conducting, behaving essentially like a two-dimensional metal. But it is a strange kind of metal, with properties dictated by quantum mechanics. For example, even if there are no mobile electrons to carry an electrical current, the electrical conductivity can never fall below a certain minimum value: it is like an electron gate that can never be fully closed.

The Manchester team has shown that graphene can be fashioned into a device called a spin valve, which discriminates between mobile electrons according to their spin. Spin is a quantum-mechanical property of electrons, and can take either of two values — somewhat akin to magnets that can orient their poles in either of two opposed directions. Conventional electronics takes no account of electron spin; but it has been suggested that a spin-dependent form of electronics, called spintronics, could provide new and powerful ways to process information. A graphene spin valve could act rather like a spintronic filter that lets a current pass only if the electrons have the correct spin.

Geim and colleagues announced their findings today at the Institute of Physics’ Condensed Matter and Materials Physics conference at the University of Exeter.