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Monday, July 28, 2008
one of these days I'll give in and get that degree in medical anthropolgy...
The Ghost Map: The Story of London's Most Terrifying Epidemic - and How It Changed Science, Cities, and the Modern World
by Steven Johnson
I'm always amazed by how much science has changed in the past 200 years. At the time of London's worst and last cholera epidemics, almost the entire scientific community was convinced the disease was carried via "miasma", or noxious odors. The fact that there was raw sewage being pumped into the Thames or sitting, festering, in peoples' basements because they couldn't or wouldn't pay for it to be taken to the countryside for disposal, had nothing to do with the spread of disease. Riiiiight.
There was an outbreak of cholera in Soho in 1854; John Snow, an epidemiologist, and Henry Whitehead, the local preacher, worked against each other and then together, as they learned more, to backtrack the spread of the disease. Snow was looking to disprove the misasma theory and Whitehead had intimate knowledge of the community, and together they determined that, after victim zero, the disease had spread to hundreds of nearby people via one particular pump. This involved tracing where people got their water, and when, and learning how the pump became infected (remember those nasty basements I mentioned above? a diaper from a cholera-infected baby infected the ground water in her basement, which passed into the well below the pump, which in turn killed hundreds of people). This was not an easy task, but there were helpful indicators. For example, a local brewery employed many men, and supplied them with all the beer they wanted while they worked, and didn't draw its water from the infected well. Those men drank enough beer while at work that they weren't thirsty at other times, and, despite being very close to ground zero, weren't affected. A former resident of the area thought the water from that particular well tasted better than other water, so her sons would regularly bring her a jug of the water. She died of cholera in the countryside.
Snow's research methods were unprecedented - though it seems obvious now, he was the first to plot the deaths on a map, and then determine which households were closer to the Broad street pump than any other, tracing that radius on the same map. The enclosed area was not a well-defined circle, but a jagged shape due to the intricacies of the streets, and pretty much enclosed the entire area suffering the cholera deaths, and only that area. Freaking brilliant.
Of course, the powers-that-be were still fixed on the miasma theory, and, despite Snow and Whitehead's work, it took another ten years or so for it to be accepted as crap. Snow died before receiving true recognition.
But once accepted, the issue of disease transmission via water was responsible for the construction of London's sewer system in the 1860's or so, much of which is still in use and now handles the waste of millions and millions of people. It led to the general clean-up of cities around the world, and enabled them to grow to the immense sizes they are today.
There's an epilogue where Johnson goes on for a while relating cholera to terrorism and other stuff. Wasn't entirely sure where that came from, but the majority of the book (pretty much all the historical portions) was fascinating.Labels: bacteria, decomposing bodies, evolutionary biology, health, history, medical, non-fiction
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Tuesday, May 20, 2008
Dork!
Title: The Archimedes Codex: How A Medieval Prayer Book is Revealing the True Genius of Antiquity's Greatest Scientist
Authors: Reviel Netz and William Noel
Apparently there's very few records of Archimedes' work; none that survive today were written in his hand. His scrolls were transferred to parchment around the end of the first millenium, and some of those were subsequently scraped down and reused, as scribes in those days often did.
The one in question here turned into a prayer book in the 1200's. That prayer book survived, though it was neglected, and was put up for auction in the late 1990's, purchased by an anonymous but very wealthy man. At that point, it was in terrible shape, ravaged by mold, bookworms, missing pages, general deterioration, and a few forged drawings on top of the prayers on top of the Archimedes.
Noel is the conservator of a museum in Baltimore that ended up leading the attempts to restore and decipher the book, while Netz is a mathematician/historian/Archimedes scholar. They wrote the book together, alternating chapters, describing both the work taking place in modern day and also discussing Archimedes' theorems, proofs, and discoveries (which are rather incredible).
At first, the fact that neither Netz nor Noel identify themselves when they start their chapters is a bit confusing, but then you realize that the chapters themselves are very, very focused - all math, or all conservation/restoration. They each manage to simplify their topics such that anyone can follow along, though the geometric proofs were so simplified and glossed over that I found them more confusing than if they'd actually gone step by step.
The conservation process sounds incredible - they managed to use all sorts of new technologies to decipher the ancient text, resulting in new discoveries both in the science of reading ancient texts and in the knowledge of Archimedes' genius.
Also fascinating was how many of the people involved in the process were volunteers. Noel got the press to do stories on the book, and all sorts of people volunteered time and knowledge. He posed issues to scientists, and for the promise of a negligible prize and the satisfaction of solving a major problem they did so. There may be a documentary out there about this saga; I haven't put any effort into tracking it down. Either way, you can get more information at www.archimedespalimpsest.org.Labels: bacteria, books, math, non-fiction
posted by ket at
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Tuesday, January 29, 2008
We're all gonna die.
Title: Good Germs, Bad Germs: Health and Survival in a Bacterial World
Author: Jessica Snyder Sachs
This book was both fantastic and terrifying. It's kindof like an intro course on bacteria, slightly helped by my prior scientific knowledge, but it definitely wasn't required.
The various sections in the book include one discussing the normal bacteria that live in and on the human body, most of which are helpful, and how when we take antibiotics that are (1) too broad, or (2) not even needed (I'm sure you know someone who insisits on telling the doctor what's wrong with them, and insisting on what they need - say, antibiotics when they have a cold, which is caused by a virus) even worse things can happen. I've seen it - there's one known as C. diff. that causes severe diarrhea and usually is picked up during a hospital visit, because if all the good bacteria in your body are wiped out, the bad ones can take up residence. You want to talk scary, there's all kinds of infections running rampant in nursing homes. Apparently someone died of GANGRENE FROM A BEDSORE in the one where my grandmother lives last week.
There's so many problems in our world involving bacteria and antibiotics. For example, farmers discovered a few decades ago that several antibiotics promote growth of animals. So they feed their livestock high doses of these antibiotics solely for growth purposes (!!!), in addition to the numerous antibiotics they're fed for "prevention" of infections (which of course means that any infections that set in will be resistant to all the drugs the farmers are already providing).
Bacteria are incredibly versatile. If one has a slight evolutionary advantage allowing it to survive a course of antibiotics, it'll populate and, before long, render that particular antibiotic obsolete. Entire classes of antibiotics have become useless since the 1950's. The practice of giving animals antibiotics that could also be used for human treatments means that by the time we try to use them on humans they're useless (this happened in Europe in the 1990's).
Big drug companies aren't too enthusiastic about researching new antibiotics, since as soon as they're put into use, they're on a course for obsolesence, meaning no more profits. And then there's the big scare stories in the news about MRSA (methicillin-resistant Staphlococcus aureus), which isn't actually resistant to everything, but definitely resistant to the most common treatments for infection, and by the time they figure out what's going on, you're dead.
I kept flagging pages as interesting while reading this. A few examples:
Recent research suggests that in an environment where deadly infections remain rare, natural seelction favors a mild, or tolerant, immuine response - because it decrease a woman's risk of miscarriage up to sisteenfold. A budding embryo, after all, is the ultimate "foreign" invader and demans enormous tolerance from the immune system if a pregnancy is to succeed. By contrast, life in communities that are plagued by infection strongly favors the survival of babies who are genetically equipped for a brutally strong inflammatory response. the increased risk of miscarriage becomes a small price to pay for higher odds that a child will at least survive to reach reproductive age. (p. 153)
For oral antibiotics, which get absorbed through the intestinal tract, the challenge is the opposite: to keep the drugs inactive until after they get absorbed. Drugs that can pull off this trick are known as "prodrugs," and familiar nonantibiotic examples include Levodopa, a Parkinson's drug that begins working only after it crosses into the brain, and cancer chemotherapies that become toxic only after entering tumors. Some of the first prodrug antibiotics came about itn the early 1990s, whieh biochemists began tinkering with the powerful new cephalosporin drugs to improve their absorption so they could be taken in pill form instead of injected. The chemists found they could greatly improve absorption by attaching a small compound (an ester) to a piece of the latger cephalosporin molecule. Further tinkering produced esters that conveniently fell away again as soon as the drug passed into the intestinal tissue, so as not to interfere with its action.
The fortuitous side effect was a group of drugs that did not produce intestinal "upset" - that is, the kind of diarrhea that antibiotics provoke when they raze our digestive bacteria. Some prodrug antibiotics turned out to have the additional advantage of being excreted primarily in urine rather than in intestinal bile, so they bypassed the intestinal tract on the way out as well as the way in. ... But prodrug antibiotics have yet to be introduced in the United States, where few physicians have heard of them. (pp. 164-165)
All those commericals for cheese and yogurts that help your digestion? They're probiotics, intended to increase the populations of the good bacterial in your intestines. Even though people aren't being properly educated as to how they work, it's nice to see the increase in their use. For quite a while now other probiotics have been available OTC in health food/supplement stores (The C. diff. I mentioned earlier? The grandma in a nursing home has gotten it pretty much each time she's been hospitalized; my mom did some research, found out about probiotics, and very effectively supplemented the prescribed treatments with probiotics.)
In case you didn't figure it out, I really enjoyed this book, even though I'm now afraid to eat pretty much any processed foods. And I plan to track down the author's earlier book, which appears to be about forensics and corpses (yay!).
And now to take things back to a more familiar (ket-type) level:
A while ago (before this blog got started) I started reading a book. Yes, it was a trashy novel. But the tie-in here is that the heroine's late husband, the father of her twin boys, had died of a random staph infection he picked up at his rock climbing gym. See, they had met through climbing, but once their sons were born, she thought it was too dangerous to go to the gym and climb, and he wanted to go one last time, and she was right! (That was my first problem with the book. Any book that suggests that rock climbing will kill you is not appealing to me, especially when the author obviously knows nothing more than how to insert climbing terms into a sentence). And then somehow seven years later this powerful-corporate-type woman is running a B&B in the middle of nowhere so she can be with the kids all the time, and somehow there's a hitman staying there, and other people trying to kill him, and somehow the local handyman comes to the rescue, and that's about when I gave up. Not on the contrived plot, though that wasn't helping things, but because there was all this talk about how he didn't need a secondary education, that being blue-colar was so admirable, and she needs to realize that, and so on. The sentiment is fine, but the way the author was so heavy-handed about it really killed the book. That, and killing off a perfectly nice-sounding climber. And no, there's no good reason for me to still remember even this much about the story.Labels: anthropology, bacteria, evolutionary biology, history, medical, non-fiction
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3:39 PM
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