10th May 2006
A lot of people have heard of “noble gases” - this is that rightmost column of the periodic table: Helium, Neon, Argon, Krypton, and Xenon. They exist pretty much on their own; it is very hard to make a compound out of them, and when you manage to, they’re fleeting sorts of things, waiting to react with whatever’s around.
Another series of noble compounds exists; the noble metals. These are named “noble” for the same reason - their relative lack of reactivity (the idea being that there are “noble” metals that hold onto their electrons in a dignified fashion, and “base” metals that deign to react with the other peasant molecules). Because of their lack of reactivity, they occur as the “native” metal much more often than the base metals (which occur as ores).
All that aside, when you want a metal that won’t react, you’re pretty good with platinum. Platinum is also very high-melting, so the development of a crucible made of platinum was a help, since various things could be heated in it without reacting with their vessel. These are curious objects. If you have any platinum jewelry, you know it really doesn’t wear. Unless it’s polished, though (and Pt crucibles usually are just brushed), it just looks like stainless steel. It doesn’t look like as expensive or special as it is until you pick it up - then you realize it’s denser than gold, and nearly twice as dense as lead - and maybe you are holding something a little bizzare.
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Posted in Drugs, Poisons, Biology, DNA, Medicine, Inorganic | 2 Comments »
9th May 2006
Here is another distinctly unfriendly-looking molecule, arsphenamine. For 30-40 brutish years, this was our single best treatment for syphilis. We owe this distinct pleasure to Paul Ehrlich, father of chemotherapy (coined the term, along with “Magic Bullet.”) In the early 20th century, he was working on histology, or staining cells. He reasoned that if we had compounds that stained only certain types of cells, maybe we could find one that would kill certain cells. Like syphilis spirochetes.
While this was a primitive theory of selectivity, Elrich used it to good effect, and six hundred five dead ends later, he released arsphenamine upon the world:
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Posted in Drugs, Hygeine, Poisons, Biology, Medicine, Inorganic | No Comments »
7th May 2006
Capsaicin is a molecule expressed by chiles (genus capsicum - this includes all pepper fruits, from jalapeno to habanero). It induces the familiar burning sensation. It, or its cousin, dihydrocapsaicin, is responsible for the hotness in essentially all hot sauces. Here is its structure:
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3rd May 2006
Yesterday, we started in on Tamiflu. From the previous article:
A lot of people have been interested in it because it’s likely to be helpful against the “bird flu” strain of the H5N1 influenza subtype. Specifically, the concern is that bird flu might mutate into a form that is transmissible between humans. Today, some humans have gotten it - however, we don’t know of anyone who got it from a human - it’s occurred only in humans who work closely with birds.
Today, we’ll talk about its biochemistry. Back to the structure:
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2nd May 2006
Here is a topical one, Tamiflu. A lot of people are interested in it because it’s likely to be helpful against the “bird flu” strain of the H5N1 influenza subtype. Specifically, the concern is that bird flu might mutate into a form that is transmissible between humans. Today, some humans have gotten it - however, we don’t know of anyone who got it from a human - it’s occurred only in humans who work closely with birds.
I’m covering the drug in two parts. Today, we’re talking about the synthesis and precursors. Tomorrow, we’ll talk about how it works biochemically as an antiviral drug. Let’s get straight to the structure:
Posted in Drugs, Biology, Medicine, Perfumey, Origin of Life | 2 Comments »
1st May 2006
Anaesthesia is just over 200 years old, but it wasn’t until the late 1800’s that local anaesthesia was used in surgery. The first local anaesthetic was cocaine. Up until then, your options were pretty much, uh, icing it. Or general anaesthesia, with all its attendant dangers. So cocaine was actually a boon to medicine, it was just a shame that it was so addictive.
The cocaine derivatives followed shortly. Below is the structure of procaine, which has a related structure and anaesthetic effects, but no euphoric effect or addictive potential. The structure of cocaine follows for comparison.
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Posted in Drugs, Biology, Medicine | 2 Comments »
30th April 2006
How smell works is one of those things we’re chipping away at, but we just don’t have it worked out yet. There is a prevailing theory. There are also some less popular but still intriguing newcomers being put forth by…intriguing newcomers. A predictive theory of smell eludes us - given a structure, we can make some guesses as to how it’s going to smell, but they’re pretty crude: sulfur stinks. Gee, thanks. It’s not quite that bad, but close.
Olfaction is also unique because a Nobel was issued for working out how every other sense works, long before that for smell. Richard Axel and Linda Buck’s smell Nobel was for working out the genes encoding odor receptors. A predictive theory of the relationship between chemical structure and odor remains elusive. Until we get it figured out, we will have plenty of weirdoes in the odorant world. After we get it figured out, well, they’ll still be weirdoes, but at least we’ll understand them and be able to relate to their stinky plight. One such rascal is indole.
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Posted in Biology, Medicine, Stinky, Perfumey | 2 Comments »
28th April 2006
Guanine is one of the five
aromatic bases that make up the genetic code. They are listed below:
Why would one be more interesting than the others? Well, guanine ends up being the weird one in a bunch of ways…
First of all, it’s not very soluble. Yesterday’s molecule, cyclodextrin, showed some examples of how solubility could modulate things like how poisonous a substance is. Neither of the purines are terribly soluble (the purines are the larger bases; guanine and adenine). One of their metabolites is uric acid. This has terrible solubility as well, and it deposits in the joints in gout. Some animals that have to conserve water will excrete solid urate - birds, for example, and bats. Bat feces — or guano — are rich in both urate and guanine. It is from guano that we get the word guanine.
Posted in Food, Biology, DNA, Medicine | No Comments »
