Saturday, July 16, 2005

Brain Cells in My Inbox.

` I have 114 things in my inbox since July 11th, which is the last time I went through my e-mail. Getting through them will take all day! ...thought I'd drag you along with me.
` After a breakfast of EdgeWalker's delicious cinnamon rolls, talking to my mom on the phone, and viewing a car rolling by with a cat leaning against its windsheild (scratching its chin as if nothing strange was going on), I'm finally getting around to my e-mail.
` (The guy driving the car parked down the street, scooped up the cat - which was still scratching its chin - and put it in the backseat.)

` I think you might be interested in what I dig up in my inbox - a lot of it is from the esteemed journal, Nature... unfortunately, as I can't afford to pay seven dollars an article, I mostly stick to news articles... but news they are.
` In a few days, they will be inaccessable to the general public unless one pays money for them, so I might as well spread the news while I can get to it!

` Carbon Dating Works for Cells
by Roxanne Khamsi.

` These are some excerpts about some surprising work done by Jonas Frisén...

By the time a halt was called to aboveground nuclear testing in 1963, levels of carbon-14 in the atmosphere had doubled beyond natural background levels, says Frisén. Since the halt, this has halved every 11 years. By taking this into account, one can see detectable changes in levels of carbon-14 in modern DNA, he says.

"Most molecules of the cell will turn over all the time. But DNA is a material that does not exchange carbon after cell division, so it serves as a time capsule for carbon," Frisén says....

Frisén and his team looked at tissue samples from more than a dozen deceased subjects, about half of whom were born after the mid-1960s. By measuring carbon-14 in their DNA, they say they can pinpoint individual cells' birth dates to within two years.

They found that all of the samples taken from the visual cortex, the region of the brain responsible for processing sight, were as old as the subjects themselves, supporting the idea that these cells do not regenerate. "The reason these cells live so long is probably that they need to be wired in a very stable way," Frisén speculates.
` Um... Wow. That kind of took me by surprise.

` Another article Roxanne did was Alzheimer's Symptoms Reversed in Mice:
The brains of people with Alzheimer's and some 50 other forms of dementia are known to have certain characteristic features, including messy bundles of fibres in nerve cells called neurofibrillary tangles. But no one has been sure whether the tangles are a cause or symptom of dementia.

Mice engineered to massively overproduce a protein called tau tend to grow more of the tangles and display the same problems with memory and learning as humans with dementia. Researchers think that it is a certain version of the tau protein, rather than a simple over-abundance, that leads to the tangles.

It has been speculated that these tau proteins, rather than the tangles, kill nerve cells.

Karen Ashe, a neurobiologist at the University of Minnesota Medical School in Minneapolis, and her colleagues hoped to untangle this mystery.

They trained mice to navigate a maze partly submerged in water, and watched for signs of memory loss. By the age of three months, mice genetically engineered to express 13 times too much tau protein couldn't remember the route to dry land, and had developed tangles in their brains.

But surprisingly, when the researchers turned off the switch promoting tau expression, the mice began to gain back some lost memory. "To tell you the truth, I expected them not to be able to get better," Ashe says.

The team reports in Science that the performance of the 'switched-off' engineered mice was roughly half as good as their normal counterparts, and twice as good as those that continued to overproduce tau. And their performance improved even through the tangles in their brains remained.
` So, we're a bit closer to understanding (and perhaps curing) Alzheimer's disease, though there are other important aspects, such as the problems involved with plaques.
` Ah yes, you know... the plaques!

` And she's written yet another: Self-Hypnosis Squelches Allergies. Alright - no more excerpts! Basically, this one's about a Swiss study where a bunch of people had learned to hypnotize themselves and focus on ski slopes and such to make their allergy symptoms lessen.
` The forty people that had stuck to doing this for two years returned to the lab were they were exposed to pollen, and their allergic reactions were measured.
` The next step of the process is where they hypnotized themselves, concentrating on snow, and were exposed to the pollen again. This time, their congestion and overall well-being was down by about a third.
` Does this mean that self-hypnosis can tell your body to not react as strongly to allergies? Or is it more of a placebo effect? Nobody is really sure, but I thought it was kinda neat.

` More a little later.

1 comment:

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