Thursday, June 10, 2010

pitching in for "itch"!

Earthen sculpture of a bust of a wild-eyed man scratching his back by Robert Arneson, titled Pablo Ruiz with Itch 
Itch (Latin: pruritus) is an unpleasant sensation that causes the desire or reflex to scratch the affected area; and the stimuli that causes it is termed Pruritic stimuli. Chronic itch represents a significant clinical problem resulting from renal diseases and liver diseases, as well as several serious skin
diseases such as atopic dermatitis.
Itch has resisted several attempts to classify it as any one type of sensory experience. Research has shown that though itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are totally different; while pain creates a withdrawal reflex, itch invariably leads to a scratch reflex. The controversy over their apparent similarity persisted because until now nobody could show that both acted through different neuronal-pathways.
The group headed by Zhou-Feng Chen at the Pain-Center in the Washington University School of Medicine, in a 2007 Nature paper, described the gastrin-releasing peptide receptor (GRPR) and implied it in mediating itch sensation in the dorsal spinal cord. GRPR mutant mice showed comparable thermal, mechanical, inflammatory and neuropathic pain responses relative to wild-type mice. In contrast, induction of scratching behaviour was significantly reduced in GRPR mutant mice in response to pruritogenic stimuli. It was significantly indicative that Gastrin-releasing peptide receptor (GRPR) is an itch-specific gene in the spinal cord. Moreover, direct spinal cerebrospinal fluid injection of a GRPR antagonist significantly inhibited scratching behaviour in three independent itch models.

a. scratching behaviour induced by intradermal injection of compound 48/80; b. PAR2 agonist SLIGRL-NH2; c. chloroquine.

As it turns out, the group has with sufficient evidence, recently shown that Itch and Pain are two different sensations propagated by different pathways, and the mechanism of itch-relief by scratching. But more about in in another post.

A gastrin-releasing peptide receptor mediates the itch sensation in the spinal cord
Yan-Gang Sun and Zhou-Feng Chen.
Nature, Vol 448,9 August 2007.

Saturday, June 5, 2010

How would you look when you grow Old?

....or if you were of Caribbean, East or West-Asian or Caucasian descent? Or how would you appear if the Italian painter of the early renaissance, Sandro Botticelli, decided to paint your face? Or would you like it, if you were to suddenly turn the tide of time to visit your childhood, or change into an Ape-(wo)man (and be proud of our common-collective-lineage)!...All this and a few more could be done at the Face Transformer hosted by the Perception lab at the Univ. of St Andrews.
To give you an idea:

Arguably the most famous and discussed picture in the world; the "Afghan Girl", later identified as Sharbat Gula, snapped by Steve Mc-Curry of the NGC on a trip to picture the refugee camps of war-torn Afghanistan.
The face-transformer reveals what she'd have looked like if she'd be of Caribbean descent (and not mid-eastern), a child, or Botticelli's muse, or when she'd be past her prime.
There is also an infant mode, and a feminiser, Modigliani's impression and a cartoon-scape but it all goes downhill from here.. Fun tool to play with, regardless.

Tuesday, June 1, 2010

"Gene Doping" - Risks behind the dehumanization of sport.

When High-glamour sporting medals and eye-popping multi-million-dollar contracts are at stake, athletes and coaches have been known to resort to drastic measures to strike gold. But as the metabolic-steroid era evolves amidst increased testing, policing and public hectoring, what other performance booster shall enter the ring? Friends, welcome the newest chip of the block - Gene-Doping!
Science is increasingly becoming humanity’s partner and handmaiden in the effort to enhance oneself, many forms of which are becoming more feasible, sought-after, and even justifiable in the quest for healthier, happier, and longer lives. Science has just added genetic manipulation to our enhancement tool kit.
Recently, the successful development of 'gene therapy' has provided the concepts, tools and opportunity for genetic modification of functions that affect normal human traits, which have been to some success, applied to alleviate diesease conditions. Frighteningly, Gene-therapy might now be also used for non-therapeutic purposes like gene-based "enhancement" of athletic performance. 
Indeed, some therapies that are being developed to help people with degenerative diseases and genetic defects live longer and more high-functioning lives might also be used to boost healthy bodies. These include treatments that regenerate muscle, increase its strength, and provides respite from ageing and

But Gene-thearpy is truly and factually in it's infancy, and results that have been tested in cell-lines or mouse-models are yet to be successfully and safely tested in human or at least non-human primate models (monkeys etc.), for adequate translation into humans; which as is understood would take its own time before a judgment could be pronounced.
For example, enhanced muscle function from the insulin like growth factor (IGF-1) or follistatin transgenes has already been demonstrated, and the celebrated lipid-modulator PPAR-delta has been known to enhance endurance performance in mice that overexpress the gene but studies in humans remain scarce, and there's no reason to believe that mice and humans would behave the same way!
In the age of internet, not surprisingly, these scientific studies are known in sport communities and are coming temptingly close to human doping. 
A 'dw-world' news-report implicates a German athletic coach in attempting to obtain a gene-transfer vector that induces expression of the erythropoietin gene.
A Chinese genetics lab reportedly offered gene-juicings before the 2008 Olympic Games in Beijing.
Gnawing close at the doping-heels, the World Anti-Doping Agency (WADA), put gene therapy on its list of no-no's back in 2004. Even as the race to discover new competitive edges gathers momentum, so does the race to detect them. Gene overexpression would likely produce broad metabolic, genetic, and proteomic changes which could be then tagged as a signature and used as a marker. New-age, high-throughput sequencing techniques, as are currently used to scan for developmental disorders and other genetic red flags, will likely be able to catch such changes too.
Although advertisements promoting products that promise to enhance athletic performance have pervaded the internet, recently it has become home for advertisements that claim to “alter muscle genes…by activating your genetic machinery”(-here), or that state “your genetic limitations are a thing of the past!” (-here) or “Finally, every bodybuilder can be genetically gifted!” (-here).
Gene-therapy and in this case -Doping could, at least in fantastic-theory could help us conjure images of a potential horror scenario of a hybrid-athlete with the speed of a cheetah, a jump  of a kangaroo and the strength of a gorilla painted by Australian scientist Robin Parisotto in his book Blood Sports, which is a funny, frightening yet enlightening history of drugs in sport.

The point of concern is that these treatments have so far only been able to produce “faster or stronger mice.” But that doesn’t mean somebody getting an Olympic medal, or scoring a goal at the World Cup Soccer, 2010, isn’t a rat.


* Science, Vol 327, 5 Feb, 2010, Gene Doping and Sport, .
* J. Appl. Physiol. 96, 1097, 2004, Viral expression of insulin-like growth factor-I enhances muscle
   hypertrophy in resistance-trained rats. 
* Cell, 134, 405, 2008, AMPK and PPARdelta agonists are exercise mimetics.
* Sci. Transl. Med. 1, 6ra15, 2009.