Pregnant women are people too

September 26, 2008

Pregnant Barbie by Matt Carman on Flickr

Pregnant Barbie by Matt Carman on Flickr

Bioethicists ask: “Why aren’t pregnant women included in most clinical trials?”

Because the trial organizers are afraid of getting sued if something goes wrong, I’d say. But that’s not fair to pregnant women, who in fact experience the states of sickness and health while pregnant – sometimes even because of conditions unrelated to pregnancy!

In fact, one study estimates that half a million pregnant women each year have conditions that require treatment, but their doctors don’t have enough information to treat the conditions safely and effectively. Many clinical trials automatically exclude pregnant women, so the data just doesn’t exist.

“Our best predictions when it comes to dosing medications can be disastrously wrong,” says Lyerly. “This conservative stance doesn’t help anybody. Without adequate research on how drugs are metabolized during pregnancy, how they are absorbed, distributed in and excreted by the body, whether they cross the placenta or affect the fetus, we have little to no evidence on how to optimize the health of pregnant women or the fetuses they carry.”

Lyerly and her colleagues at Johns Hopkins University’s Berman Institute of Bioethics and Georgetown University clearly recognize the many challenges that need to be addressed in order to safely include pregnant women in clinical research. In fact, they are convening a meeting with officials from the FDA, NIH and leading experts in obstetrics, gynecology and maternal/fetal medicine next year to address these issues and come up with practical, public policy and moral solutions.

Read the press release: An ethical argument: include pregnant women in research

Whose limb is it anyway?

September 3, 2008

photo by dolbystereobenIt’s a little weird to think of limb ownership as a field of study. Of course my right arm belongs to me; who else would it belong to?

Our brains process a lot of information coming from our extremities. Beyond the usual sensations of touch – heat, cold, pain, tickling, and so on – we have proprioception, the information telling us where our body is in space. It’s how you can touch your nose even when your eyes are closed.

But when your eyes are open, your brain uses that information too.

Hence the strange effect of the rubber hand illusion , where scientists put a rubber hand on a table in front of someone, and stroke both the rubber hand and the subject’s real hand with a paintbrush. The subject ends up thinking she “owns” the rubber hand. To quote a typically intelligent YouTube commenter:

well duh because theyre seeing it, and they already felt the brush on them so your sense mix up ahahah idk.

photo by stagewhisper

photo by stagewhisper

In fact (and this is something the YouTube commenters were eager to see, although it’s not in the video), if you make stabbing motions toward the rubber hand, the subject will freak out. Scientists can detect activity in the “I’m freaked out” section of the brain. (They have that mapped out, I guess). The subject really thinks the rubber hand is hers.

A new study shows an interesting side effect of “owning” a rubber hand: the subject disowns her existing hand. The researchers found that the real hand’s temperature drops during the experiment, and tactile information from that hand is processed more slowly.

photo by raysto

photo by raysto

Rubber hands sit still and look funny, but it turns out there’s a more convincing way of portraying a fake hand: using a mirror.

If you rig up a mirror so that the subject is looking at, say, their real left hand and a reflection of their left hand, they start to believe they are looking at their left and right hands. The standard setup has the person move, clench, and stretch their hands simultaneously. Watch the video and you’ll see how disconcerting it is when, around 1:55, the demonstrator moves his real hand differently from the reflection. I’m not attached to those hands and I still got weirded out!

A surprising result of all this brain confusion is that it even works for people who are missing a limb. If an amputee thinks that their missing limb is clenched, cramped, or painful, a few minutes with a mirror box can convince their brain that the limb looks and acts normally. In a recent study, after 4 weeks of mirror therapy all of the amputees felt a decrease in their everyday phantom pain.

Why do amputees feel phantom pain at all? Some say it’s a problem with the cut ends of nerves; some say it’s all in their head. One theory, supported by the mirror therapy results, says that the brain is just guessing, in the absence of better information, at what sensation the limb should be feeling. The mirror therapy provides more information, untrue though it may be, leading to relief.

In this fascinating story about itch, mirror therapy helps. Here is the patient’s experience:

The first thing he expressed was disappointment. “It isn’t quite like looking at my left hand,” he said. But then suddenly it was.

“Wow!” he said. “Now, this is odd.”

After a moment or two, I noticed that he had stopped moving his left arm. Yet he reported that he still felt as if it were moving. What’s more, the sensations in it had changed dramatically. For the first time in eleven years, he felt his left hand “snap” back to normal size. He felt the burning pain in his arm diminish. And the itch, too, was dulled.

“This is positively bizarre,” he said.

craneflies

September 3, 2008

Dear Chris,

You asked what crane flies eat. Wikipedia says adults eat either nectar, or nothing.

You’re familiar with bugs like cicadas and mayflies and moths: they live long, happy lives as larvae … and then turn into adults so they can have sex one last (er, first) time before they die. They don’t always bother to eat in their adult stage, so they don’t need mouthparts.

Crane flies follow a similar schedule (the larvae eat forest detritus). They might not eat – but then again, researchers have seen craneflies visit flowers, “probably for nectars,” say the entomologists at the CMNH in Pittsburgh.

It seems bug species currently outnumber entomologists, so they don’t have time to answer all of our pressing questions about crane flies. They did assign crane flies to the family Tipulidae, and classified them as a type of fly, so I guess that’s about all we can expect for now.

Obviously this needs further study. Why don’t you catch a cranefly, offer to cook it dinner, and see what it requests?

Love,
Beth