MedWorm provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest medical blog items that have been tagged with 'analytical chemistry'. Sat, 03 Sep 2011 02:48:30 +0100 http://www.medworm.com/index.php?rid=4349677&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2011%2F01%2F14%2Ffishing_around_for_biomarkers.php Everyone in this industry wants to have good, predictive biomarkers for human diseases. We've wanted that for a very long time, though, and in most cases, we're still waiting. [For those outside the field, a biomarker is some sort of easy-to-run test that for a factor that correlates with the course of the real disease. Viral titer for an infection or cholesterol levels for atherosclerosis are two examples. The hope is to find a simple blood test that will give you advance news of how a slow-progressing disease is responding to treatment]. Sometimes the problem is that we have markers, but that no one can quite agree on how relevant they are (and for which patients), and other times we have nothing to work with at all. A patient's antibodies might, in theory, be a good place to look for m... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=4349677 Fri, 14 Jan 2011 12:58:24 +0100 4349677 http://www.medworm.com/index.php?rid=4241934&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2010%2F12%2F08%2Fnasas_arsenic_bacteria_a_call_for_followup_experiments.php Since the posts here on the possible arsenic-using bacteria have generated so many comments, I'd like to try to bring things together. If you think that the NASA results need shoring up - and a lot of people do, including me - please leave a comment here about what data or new experiments you'd want to see. I'll assemble these into a new post and try to get some attention for it. The expertise among the readership here is largely in chemistry, so it would make sense to have suggestions from that angle - I assume that microbiologists are putting together their own lists elsewhere! I know that several readers have already put forward some ideas in the comment threads from the earlier posts - I'll go back and harvest those, but feel free to revise and extend your remarks for this one. So, t... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=4241934 Wed, 08 Dec 2010 19:59:10 +0100 4241934 http://www.medworm.com/index.php?rid=4098410&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2010%2F10%2F22%2Fthe_latest_technology.php Well, the latest for 1960, anyway. That's the Bruker KIS-1 NMR machine there, folks, operating at 25 MHZ, and ready to dim the lights in the whole building when you switch on that electromagnet. Allow about 12 hours of acquisition time to get a decent spectrum. For those of you outside the field, a 300 MHZ NMR machine is now considered a average workhorse instrument, and should give you a spectrum (with resolution that would have made someone back then faint with joy) in a minute or so of acquisition time. We can do things with modern machines that they wouldn't have even dreamed of back in 1960, and people are still thinking up new tricks. All hail NMR! (Source: In the Pipeline) In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=4098410 Fri, 22 Oct 2010 15:35:28 +0100 4098410 http://www.medworm.com/index.php?rid=3823147&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2010%2F08%2F04%2Frunning_your_fingers_over_a_single_molecule.php Readers will remember the extraordinary pictures of individual pentacene molecules last fall. Well, the same IBM team, working with a group at Aberdeen, has struck again. This time they've imaged a much more complex organic molecule, cephalandole A. As that link details, the structure of this natural product has recently been revised - it's one of those structural-isomer problems that NMR won't easily solve for you. Here's a single molecule of it, imaged by the same sort of carbon-monoxide-tipped atomic force microscope probe used in the earlier work> Now, it's not like you can just look at that and draw the structure, although it is vaguely alarming to see the bonding framework begin to emerge. If you calculate the electon densities around the structure, though, it turns out that the re... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=3823147 Wed, 04 Aug 2010 15:02:19 +0100 3823147 http://www.medworm.com/index.php?rid=3585818&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2010%2F05%2F20%2Ffloyd_landis_the_isotopes_werent_lying_after_all.php This post from 2006 on the science behind Floyd Landis's suspicious steroid blood tests set my blog record for comments - the debate went on and on about Landis, about the lab that reported the results, about how the samples were handled, etc. Well, Landis has now admitted using performance-enhancing drugs for most of his career. Widely, expensively, and thoroughly did he use them. The blood test was correct. Carbon isotopes don't lie. (Source: In the Pipeline) In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=3585818 Thu, 20 May 2010 16:07:45 +0100 3585818 http://www.medworm.com/index.php?rid=3508437&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2010%2F04%2F27%2Fmasses_of_data_in_every_sample.php I've said several times that I think that mass spectrometry is taking over the analytical world, and there's more evidence of that in Angewandte Chemie. A group at Justus Liebig University in Giessen has built what has to be the finest imaging mass spec I've ever seen. It's a MALDI-type machine, which means that a small laser beam does the work of zapping ions off the surface of the sample. But this one has better spatial resolution than anything reported so far, and they've hooked it up to a very nice mass spec system on the back end. The combination looks to me like something that could totally change the way people do histology. For the non-specialist readers in the audience, mass spec is a tremendous workhorse of analytical chemistry. Basically, you use any of a whole range of techniq... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=3508437 Tue, 27 Apr 2010 11:17:52 +0100 3508437 http://www.medworm.com/index.php?rid=3071456&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2009%2F12%2F09%2Fwater_and_proteins_inside_cells_sloshing_around_or_not.php Back in September, talking about the insides of cells, I said: There's not a lot of bulk water sloshing around in there. It's all stuck to and sliding around with enzymes, structural proteins, carbohydrates, and the like. . ." But is that right? I was reading this new paper in JACS, where a group at UNC is looking at the NMR of fluorine-labeled proteins inside E. coli bacteria. (It's pretty interesting, not least because they found that they can't reproduce some earlier work in the field, for reasons that seem to have them throwing their hands up in the air). But one reference caught my eye - this paper from PNAS last year, from researchers in Sweden. That wasn't one that I'd read when it came out - the title may have caught my eye, but the text rapidly gets too physics-laden for me to ... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=3071456 Wed, 09 Dec 2009 13:45:07 +0100 3071456 http://www.medworm.com/index.php?rid=2556344&cid=t_102665_149_f&fid=35784&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FTheChemBlog%2F%7E3%2FrcCWFvB1Qmk%2F The US supreme court ruled a few weeks ago that the chemists that perform tests in forensic analysis are not immune from cross examination by defense attorneys.  It’s not surprising that the American judicial system did not inherently allow for this, since it’s a very biased and f.ed up system.  With this tool in the briefs of attorneys, it sets up a very real and very likely chance that a number of methods used in forensic science, as conducted in the state crime labs, will not hold up to scrutiny.  Not because they’re necessarily invalid (though, we shall see about that), but because they’ve not been done with the appropriate controls – an argument mentioned in the majority arguments by Scalia: He cited one report, for example, that said “there is wide ... The Chem Blog blogs http://www.medworm.com/rss/comments.php?id=2556344 Tue, 30 Jun 2009 13:14:58 +0100 2556344 http://www.medworm.com/index.php?rid=1815727&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2008%2F09%2F23%2Fyou_call_that_an_xray_source.php Over the years, when some puzzling feature of a drug candidate’s binding to a target came up, I’ve often said “Well, we’re not going to know what’s happening until some lunatic builds a femtosecond X-ray laser”. Various lunatics are now pitching in to build some. I’m going to have to revise my lines. The reason I’d say such a mouthful is that we already, of course, get a lot of structural information from X-ray beams. Shining them through crystals of various substances can, after a good deal of number-crunching in the background, give you a three-dimensional picture of how the unit molecules have packed together. Proteins can be crystallized, too, although it can be something of a black art, and they can be either crystallized with or soaked with our small molecules, givin... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=1815727 Tue, 23 Sep 2008 12:10:04 +0100 1815727 http://www.medworm.com/index.php?rid=1764219&cid=t_102665_149_f&fid=35776&url=http%3A%2F%2Fpipeline.corante.com%2Farchives%2F2008%2F09%2F04%2Fxray_structures_handle_with_care.php X-ray crystallography is wonderful stuff – I think you’ll get chemists to generally agree on that. There’s no other technique that can provide such certainty about the structure of a compound – and for medicinal chemists, it has the invaluable ability to show you a snapshot of your drug candidate bound to its protein target. Of course, not all proteins can be crystallized, and not all of them can be crystallized with drug ligands in them. But an X-ray structure is usually considered the last word, when you can get one – and thanks to automation, computing power, and to brighter X-ray sources, we get more of them than ever. But there are a surprising number of ways that X-ray data can mislead you. For an excellent treatment of these, complete with plenty of references to the rece... In the Pipeline blogs http://www.medworm.com/rss/comments.php?id=1764219 Thu, 04 Sep 2008 12:41:13 +0100 1764219 http://www.medworm.com/index.php?rid=478755&cid=t_102665_87_f&fid=34867&url=http%3A%2F%2Fwww.thediabetesblog.com%2F2007%2F03%2F06%2Fthe-first-urine-test-to-detect-insulin-doping-in-athletes%2F Filed under: Type 1, Type 2, Childhood, Adult Onset, Lifestyle, Drugs, SupportScientists in Germany are reporting development of a urine test that finally can identify athletes who misuse certain kinds of insulin in an illicit attempt to enhance performance. An article scheduled to appear in an April edition of Analytical Chemistry says it is possible to detect the misuse of insulin in a urine sample. Scientists had not attempted to develop a test in the past because of the presumption that it was impossible to detect misuses of insulin. Because insulin is rationed and used efficiently by the body, a byproduct of insulin would be theoretically undetectable. However, with the advent of the newer long-acting insulin analogues, scientists are now able to identify degradation product in the ur... The Diabetes Blog blogs http://www.medworm.com/rss/comments.php?id=478755 Tue, 06 Mar 2007 05:00:00 +0100 478755