A team led by Prof. Jennifer Helisseeff at Johns Hopkins University recently presented a novel implant, that can be injected as a liquid under the skin, then modeled to appropriate shape, and solidified by exposure to light. The composite material is made by mixing polyethylene glycol (PEG), a widely used artificial polymer, with hyaluronic acid, a natural polysaccharide. The ratio of PEG and hyaluronic acid can be tuned, such as to modulate the properties of the final polymer: it can then be adapted to the location where the injection takes place (fat, muscle, skin). After injection under the skin (tests were made on rodents and with human patients), the implants could be massaged into shape. Finally, exposure to visible light initiated a cross-linking reaction between the PEG molecules, transforming the implant into a solid, shape-persistent hydrogel with entrapped hyaluronic acid molecules.

Although the newly-develped implants possess good longevity and stability, it was found that they cause more inflammation than currently used implants. However, the presented technique will probably find numerous application in reconstructive surgery, as soon as the last problems will have been sorted out.

The liquid polymer is injected, and solidified by irradiation.

Reference: A. T. Hillel et al., Sci. Trans. Med. 2011, 3, 93ra67. DOI: 10.1126/scitranslmed.3002331

No better illustration of the dual character of virtually any substance can be found than this report recently appeared in the FASEB journal. A team of researchers from Paris led by Patrick P. Michel investigated the beneficial effects of nicotine for neuroprotection. Their findings suggest potential development of novel therapies for diseases such as Parkinson’s, that target nicotine receptors: according to experiments performed on brain cells of mice, they found that nicotine seems to provide protective effect against some type of neuron loss, a symptom widely associated to Parkinson’s disease.

Of course, as Gerald Weissmann, Editor-in-Chief of The FASEB Journal, comments on ScienceDaily: “If you’re a smoker, don’t get too excited. Even if smoking protects you from Parkinson’s, you might not live long enough to develop the disease because smoking greatly increases the risk for deadly cancers and cardiovascular diseases [...]” Still, this discovery is significant. Not only in terms of Parkinson’s diagnosis and treatment, but also because it shows that a usually ill-considered substance such as nicotine can have some positive effects – it might be a matter of dose after all! This is a lesson for scientists, who sometimes tend to neglect fields of research on the pretext they are not fashionable enough, and also for those who fund scientists: it is probably not the simplest task to raise money for studying such ill-reputed compound as nicotine.

References:

D. Toulorge, S. Guerreiro, A. Hild, U. Maskos, E. C. Hirsch, P. P. Michel., The FASEB Journal 2011, 25 (8), 2563 DOI: 10.1096/fj.11-182824

ScienceDaily. Retrieved August 1, 2011, from http://www.sciencedaily.com­/releases/2011/08/110801111738.htm

*born Philippus Aureolus Theophrastus Bombastus von Hohenheim…

When input strands are added to a mixture containing the sophisticated DNA system, cascade reactions between the DNA strands are initiated, that sequencially zip and unzip from one another depending on the inputs. After the computation has been performed (ie, the cascade reactions stop), the response appears under the form of a given fluorescence colour. For each output, a specific colour indicates ‘0′, and another colour corresponds to ‘1′ (like ‘real’ computers, this one works in binary numbers). The researchers used the ’square root solving problem’ to demonstrate the capacities of their system. However, one of the remarkable points of the piece of work is its very systematic design: one can therefore imagine different function for such a system, like diagnosing illnesses: such a device could provide specific responses depending of what chemicals are present in a patient’s blood, for example.

After this first charge against conservative academic research came the second strike, still in Nature, in the form of a whole issue (!) entitled “The future of the PhD”. This time it is not about chemistry only, but about the PhD system as a whole. A series of articles (“Education: the PhD factory”, “Education: rethinking PhDs”) and opinions (“Reform the PhD system or close it down”, “What is a PhD really worth?”, “Fix the PhD”) highlight the qualities and defaults of PhDs – and raise numerous hot debates among readers. Essentially, there are more PhD students and more doctoral programmes than ever, and not enough academic positions for all these graduates – in most fields, the only jobs PhD students have ever been trained for. Consequently, hosts of PhDs will have to spend 5 or 10 tiresome years in ill-paid postdocs (waiting for an hypothetical academic position) or go to work in industry, but won’t be prepared for that: too specialized, not having the required ‘real-world’ experience, too expensive, etc. None of these perspectives seems appealing, particularly when speaking of people who spent years and significant amounts of (taxpayers’) money to achieve the highest levels of education.

There is probably no ready-made solution to these questions, but they must be of direct concern to the research world – particularly, to PhD students and recent graduates: they must be aware of the opportunities – or lack of them – that await them in the ‘post-doctorate’ (in the literal sense) world, and of what it takes to be more attractive for a future career: broad field of knowledge, soft skills and profesionnal education.

In my imagination, conferences in the past involved a passionate speaker (usually wearing a hat) who was disclosing his/her latest discoveries, vehemently speaking or writing on a blackboard (sometimes performing live experiments) while the audience was listening in a profound, respectful silence.

Today, what I saw was somewhat different – and I’m not talking of speakers not wearing hats. Actually, I was at a presentation seating next to a professor, who was preparing the powerpoint he was going to present in the afternoon. To do this, he had to ask his collaborator, seated next to him, about the meaning of some graphs he intended to include in the presentation. This took approximately one hour, and was quite disturbing to all the people around, since the discussion included mumblings and laughters.

So, without even considering half of the members of the audience who checked their e-mails or the news on CNN every 5 minutes on their iPhone, I was wondering whether the speaker was noticing this lack of attention. The answer I guessed is probably no (because speakers are generally too busy and stressed to notice what happens behind the front row) but still, I’m wondering why people go to talks to prepare their own slides??

Besides, I wanted to mention today’s plenary session, where Prof. Michael Grätzel from EPFL (it’s always funny to go abroad to attend talks from our own faculty) presented the latest advances in dye sensitized solar cells (DSCs). I still hope to write a full post about Prof. Grätzel’s work sometimes (like next October 6th), and here I just want to mention that there is now a Michael Grätzel Center in Wuhan (China) which, I think, is quite something. The optimism and enthusiasm of Prof. Grätzel are always extraordinarily communicative (especially when it comes to recent applications), and I’m deeply convinced that the future is bright for dye-sensitized solar cells

Now, to be complete, I must mention that WolframAlpha comes with some limitations – or should I say, it is still being developed – but may well become an interesting alternative to other search engines. Among the limitations, if for example you enter ‘taxol’ in the query bar, you obtain a very approximate structure of the molecule, with no mention of stereochemistry, although it is of prime importance for this type of molecules. It also seems that the notion of ‘buffer’ does not (yet) exist, even though a ‘buffer calculator’ would be quite useful…

So have a look at WolframAlpha if you need simple information (on chemistry or whatever else btw) and also have a look at their blog, reporting their latest innovations and ideas.

Chemically speaking, I’ll attend next week the International Symposium on Macrocyclic & Supramolecular Chemistry in Maastricht, the Netherlands, where I hope to find inspiration both for researching and for blogging!

Histamine is a very simple molecule which is present is basically every single cell of our bodies. It is produced through enzymatic decarboxylation of amino acid histidine. Histamine’s many roles include neurotransmission (particularly in the sleep regulation mechanism) and immunological response, explaining why it is involved in various immunological troubles, ranging from relatively mild allergies to severe autoimmune diseases.

Histamine

A high proportion of histamine is stored in cells called mastocytes, which are located mostly at ‘risky’ places where the outside world can come into contact with our internal tissues: skin, lungs, mouth, nose… sounds like places where we can feel allergies right? When an allergy reaction takes place, the (harmless to non-allergic people) allergen interacts at the surface of the mastocyte, inducing the release of a massive amount of histamine in the surrounding environment. This results in well known consequences, such as mucuous secretions, itchiness, conjunctivitis. To produce these effects, histamine needs to interact with particular receptors, called, not so surprisingly, histamine receptors. The easy solution to overcome these effects is to prevent the histamine+receptor interaction: this is done thanks to antihistamine molecules which are also binding to histamine receptors, but without inducing allergic symptoms (pharmacologically speaking, antihistamine is an inverse agonist of histamine).

Finally, what about the widely reported drowsiness side-effect? As stated before, histamine plays a role in the sleep regulation. Histamine metabolism is perturbated upon antihistamine injestion, and one of the side effects is a (slight) inhability to maintain vigilance. Recent drugs (including my relieving cetirizin) are supposed to possess attenuated side-effects, but in my experience it is still not perfect since I tend to feel an urge to sleep after each intake…

Cetirizine, the active compound of many antihistamine drugs.

And now, for people who would (should) be more interested in Prof. Müller’s work than in greek terminology, here are a couple of links to some of his most significant publications, mainly dealing with huge porous capsules, and therefore containing amazing pictures.

Spherical polyoxomolybdate based capsule. The 20 pores are occupied by guanidinium cations.

Angew. Chem. Int. Ed. 2004, 43, 4466-4470;
Angew. Chem. Int. Ed. 2003, 42, 2085-2090;
Angew. Chem. Int. Ed. 2003, 42, 5039-5044;
Angew. Chem. Int. Ed. 2002, 41, 3604-3609;
Angew. Chem. Int. Ed. Engl. 2000, 39, 1614-1616;

The good news is that people from the chemical stores told me the situation should improve this summer, but the prices will never go as low as before – there is apparently lots of money to get if you’re an acetonitrile supplier…