Posts Tagged ‘Biology’
(Science through story is an ongoing series in which I try to figure out how to make the rest of the world as interested in science as I am.)
Words matter. Since I’m both a scientist and a writer, they matter to me even more. So I never felt guilty taking my college freshmen to task when they misused words in their attempts to explain a scientific process. (Example: Molecules don’t “want” to move from an area of high concentration to low concentration. As non-sentient particles, molecules lack the ability to “want” anything.)
But to the point of this post: one of the moms at my kids’ bus stop was talking about antibiotics. Her daughter had been sick, and had been to see the pediatrician. The doctor told this mom that her daughter probably had a virus, and she needed to take care of her illness with bed rest and fluids. I was thrilled, having heard too many stories of moms who shop around for doctors until they find one who will give them an antibiotic prescription they don’t need.
And then she said it. “What the doctor said was that when people don’t finish their antibiotics prescriptions, the bacteria learn to mutate and become resistant to the medicine.”
So close, yet so far.
It’s a great visual, isn’t it? Can’t you see a little circle of germs in a football huddle, heads together, saying, “Okay guys, it’s looking pretty bad out there for us right now…the kid’s resting up, mom’s got the fluids going, and now they’re bringing in the big guns, the medicine…so we’ve got no choice: it’s time to go nuclear on this thing. We have to learn to mutate, in order to survive.”
It’s one of the most common misconceptions in biology: that organisms adapt (or evolve) because they have to in order to survive. This misunderstanding robs the genetic basis of evolution of its magic, its randomness, its terror, really – that if something doesn’t happen by chance in a species’ genetic code, it’s going to vanish from existence.
How does that misconception spread? Here’s an example: Antibiotic MRSA in Livestock May Spread to Humans.
Here’s a few quotes from the article:
Livestock in the United States may be building resistance to deadly bacterial infections
‘Most of the ancestral human strains were sensitive to antibiotics, whereas the livestock strains had acquired resistance on several independent occasions…’
Once the strain infected livestock, the strain likely changed into several different types, some of which are resistant to various antibiotics, said Fitzgerald, and it is now a two-way street.
Building. Acquired. Changed. These terms are very human. We build buildings, acquire new items, change clothes. It makes the bacteria seem like they will do what it takes to survive. After all, wouldn’t we? Wouldn’t we build a wall, acquire food sources, change our behavior if we knew a hurricane is coming?
When we hear a word, our brains fetch a definition for that word that matches our experience. In science, that’s how we get from “species evolve because a random act gives them the ability to survive in their environment” to “species evolve because they need to adapt to their environment.” It’s why I’d like to see news articles meant for a mainstream audience include a paragraph (even a sidebar) on the basics of how a process works to answer questions like:
“Why does it matter if I take antibiotics when I don’t need them?”
“How does finishing my prescription help drop the chances of adding to the problem?”
Time is precious – we are challenged as science writers to distill the essentials from a scientific process to create concise and interesting ways to convey both the problem and a solution.
(Next post: a possible solution.)
We humans love our libations: after a long work week, lots of us decide to unwind with a drink or two. (For some of us, it might be even more than two.) What happens after we take that drink? Here’s a brief overview of ethanol’s effect on the body.
Pick Your Poison
Absorption of alcohol starts even before we take our first swallow. Ethanol enters through the blood vessels in the mouth, throat, and (primarily) the stomach, which is why what and how much we eat affects how fast we feel the effects of our drinks. The liver gets first crack at this blood, which is a good thing – one of the liver’s many jobs, of course, is to remove toxins of all sorts in order to protect the rest of the body. You may want that alcohol (or recreational drug, or pill for your headache) to get to your brain, but to the liver, these are poisons. Unfortunately, the liver isn’t prepared to handle a lot of alcohol quickly, so if you’ve had more than a few sips, some of the ethanol is going to make it through.
Going to Your Head
The body takes care of its most important organs first. Of primary importance is the brain, which hogs about 20% of our body’s total oxygen, and about 30% of our caloric intake daily. Therefore, after its scrubbing by the liver, the nutrient rich blood heads for the lungs, and then the brain. All well and good if you’ve had a healthy meal, but a bit of a problem if you’ve had, say, two shots of bourbon on an empty stomach.
If you do have enough alcohol in your bloodstream to overpower the liver’s best efforts, the evidence is going show up on your breath. Since ethanol is volatile enough to evaporate from the blood into the warm, moist air of your lungs, a little bit gets expelled when you exhale. Thanks to Dr. Robert Borkenstein, inventor of the breathalyzer, we’ve been able to use this phenomenon to get drunk drivers off the road since 1954.
The brain itself is protected from viruses, bacteria, and other undesirables in the bloodstream by a blood brain barrier, but ethanol has no problem reaching brain cells. Every system in the brain gets put out of commission by the effects of alcohol. A pickled prefrontal cortex means you forgo good judgement, while a sodden hypothalamus “forgets” to make the hormone that prevents you from urinating all the time (and you were blaming watery beer). The voluntary muscle control centers in your cerebellum can’t keep you from staggering into walls. And your emotional control center (the limbic system)? Forget it. You’re either euphoric, angry, or a weepy mess. Have more than a few and it gets worse, since an alcohol soaked medulla is going to slow your heart rate and breathing. Your body eventually decides something’s trying to kill you, and it rebels. Up it comes, and out you go – your body vomits out the toxic stuff, and you pass out.
The Party’s Over
Morning comes – and with it, the hangover. There’s almost as many theories of why we get hangovers as there are surefire hangover “cures.” You’re certainly dehydrated, and you’re nauseous from an irritated stomach and intestines. Circulating in the bloodstream are high levels of acetaldehyde, a byproduct of alcohol metabolism that’s more toxic than the ethanol itself. You’re exhausted, since the alcohol the night before inhibited production of the natural stimulant glutamine, and your body made up for for its depleted stores while you “slept it off.” These high levels of glutamine kept you from really getting any quality sleep at all. If you had a dark liquor or red wine, you also have congeners (byproducts of alcoholic fermentation) like methanol floating around. When the body tries to break down the methanol, you get…formaldehyde.
Talk about being pickled…
The first time I ever gave my daughter Betsy, now three and a half, an Oreo cookie, she pulled it apart, licked the center clean of icing, and then ate each half cookie separately. I was baffled. This is a kid who’s never seen a commercial for Oreos in her life, nor had she ever seen anyone eat one. “Another,” she declared. I gave her one. The same process ensued, after which, with some cajoling, she drank the rest of her milk, and left. An ordinary snack time experience, but one worth considering; why do young humans explore, and old ones accept? What makes us bite into the cookie instead of pulling it apart?