Giving mice Down’s syndrome
A “technical” step forward has been made in understanding Down’s syndrome: researchers have successfully introduced 90% of the 250 genes on human chromosome 21 into the embryonic stem cells of mice. A normal person has two copies of chromosome 21, but a person with Down’s syndrome has three, making it part of the aneuploidy class of disorders (of which I have touched on in the past). Using the compromised stem cells, researchers were able to create a strain of mice that carried the extra chromosome.
This strain of mice has problems with memory, brain function, and heart formation. It remains to be seen whether they show a disposition towards other diseases like leukemia, which people with Down’s often have to deal with. By creating the modified stem cells, researchers hope to learn which genes control which aspects of the Down’s symptom. For instance, by learning which genes affect heart formation, they hope to one day create stem cell therapies that will turn off the genes of developing children with Down’s.
While far from a cure, this ability to create strains of mice that can be experimented with shows huge promise in the field of Down’s research. If scientists can discover which genes control brain and heart formation, and which genes alter thyroid function, they can potentially suppress their expression in developing fetuses at some point down the road.
This, of course, is assuming that such therapies will be legal in places like the United States, whose laws are quite restrictive when it comes to stem cell research. I suppose that one could go to a place like the UK for treatment, but I suspect that if real-word promise is offered for relatively mainstream conditions, conservative public opinion in the US will change. Slowly.
The cheerio effect
If you’re like me, you probably used to play with your cheerios as a means of stalling in the morning before going to school. I used to play with my cheerios and see what sorts of patterns I could make without actually touching them. I used to do the same with bubbles in my juice. I used to try to influence them and then figure out why they were behaving the way they did. Apparently I wasn’t the only one who was fascinated by liquids and the way they interacted with solids because there’s a new study that is due to be published in the American Journal of Physics that explains the physics of cheerios a bowl of milk. I always used to like eating cheerios because they didn’t break down into particulate matter, and I never had to hunt for the last cheerio in a bowl full of milk. Now I know why.
The clumping effect is a result of a combination of surface tension, buoyancy, and gravity. Cheerios float, but they also press down on the surface of the milk, creating little concave indentations in the surface. So when two cheerios float near one another, they “fall down” each other’s cave, creating the appearance of an attractive force.
Cheerios on the edge of a bowl of milk are sitting atop the meniscus of the milk, and when there’s a chain of them along the edge, it’s because they’re atop the meniscus, forming their own little concave indentations making them seem sticky.
From MSNBC.
Minotaur rocket puts on an impressive sunset show
Those of you living in southern California might have seen the impressive spectacle that was the six-foot Minotaur rocket blasting off a half an hour after sunset last night. Residents as far away as Utah, Nevada, and Arizona reported seeing the impressive corkscrew-like contrail caused by winds in the upper atmosphere, and authorities were inundated with calls wondering what had just happened.
The Minotaur lifted off at 7:24 PDT, carrying an experimental military spacecraft, but clearly the most impressive thing about the launch were the accompanying photos. You can check out the Flickr photostream for more photos. I haven’t found any particularly good high-resolution photos, but I did come across an old NASA Photo of the Day, showing a similar missile launch of a Minuteman II rocket — which is, incidentally, my new desktop background. The Minotaur actually uses decommissioned Minuteman 2 ICBM missile and solid-propellant motors for its first two stages.
The rockets obviously do not fly in a corkscrew pattern. The swirls come from unburned fuel and water from the contrail being frozen in the less dense upper atmosphere where it is twisted by the wind currents. These frozen particles are high enough in the sky to be reflected by the sun, creating the fantastic spectacle.
This Spaceflight Now article has more details on the actual satellite that was launched.
Fetal crying
Fetuses, it seems, can cry too. New research shows a fetus going through the same motions an infant or young child does when they cry: sharp, irregular intake of breaths, an open mouth, and chin quivering. There’s even a video of a moving ultrasound showing a girl crying at 28 weeks. I found the video absolutely amazing, not ever having seen a still ultrasound or anything of the sort, being an only child and one of the youngest in my extended family. It aroused protective feelings in me, and I’m sure I’m not the only one who’s going to feel that way when they see the video clip.
I expect that anti-abortion advocacy groups will use this as fodder for their campaign, especially since they already use hurting an unborn child as a tool against abortion. This video comes at a time when the subject of fetal pain is being hotly debated, and other studies are indicating that they cannot.
Their report, being published today in the Journal of the American Medical Association, is based on a review of several hundred scientific papers, and it says nerve connections in the brain are unlikely to have developed enough for the fetus to feel pain before 29 weeks.
Well, I just saw a video that begs to differ. Arguing whether what I saw was pain or not seems to be a semantical argument at best, because that fetus was clearly in discomfort. Assuming (and this is a big assumption to make right now) that the fetus can feel pain, fetuses being aborted in the 28-29 week stage will likely have to anesthetized before they can be aborted for ethical reasons.
“This is an unknowable question,” said Dr. David Grimes, a former head of abortion surveillance at the Centers for Disease Control and Prevention who now delivers babies and also performs abortions in Chapel Hill, N.C.
“All we can do in medicine is to infer.” Nonetheless, he said, the new article makes a compelling case for lack of pain perception in fetuses before 29 weeks.
Indeed it is “unknowable,” but I think this video makes a strong case for fetal pain, and certainly crying. While I have mixed feelings on the abortion issue, and I don’t feel that this is the place to air them, I certainly sympathize with that fetus. Hearing tones at the 100Hz level at 95dB would probably make me cranky, too.
Buy your own DNA kit
You can now buy your own home DNA testing kits online from Amazon and Target. The kit doesn’t offer much, but it is cute. One option allows you to store it, and another, more expensive option allows you to see how you stack up to various races. (Whatever that means.) It’s cute, but not very impressive since one could just as easily preserve a few strands of hair in an envelope.
Eventually, such kits could lead to more extensive DNA testing: to see what genetic predispositions one might have. Cancer, Crohn’s, heart disease, etc. I can see mail away DNA testing being big business in ten years. I would suspect that insurance companies might offer discounted rates to those customers that consent to a DNA test before they enroll. Such testing could never be mandatory (per federal law), but I’m certain that some incentives could be offered to aid them in getting a better health picture before of a potential client before a contract is made.
Right now, though, the sort of “DNA testing” offered is largely useless information: it’s too general for it to have any real use.
Drug-resistant bacteria strains becoming more virulent
I have written about drug-resistant bacteria in the past, and not a day goes by that there isn’t some press release on Eurekalert about antibiotic resistant bacteria. Most of these press releases are negative, and today was no exception. Every time I read about drug-resistant strains in the news, it freaks me out a little bit, and makes me uneasy deep down. Perhaps because I am more familiar with the subject than most, and I know that there isn’t much being done about the problem in the medical community because it’s not a profitable problem to tackle for the big pharmaceutical companies. Traditional antibiotics like macrolides, penicillin derivatives, fluoroquinolones, and others have been “enough” for most people… until recently.
My unease comes from several different factors. One of them is that here in the United States, it takes roughly ten years for a new chemical entity (NCE) to go from concept to approval to market. This ensures (in theory) that a drug is relatively safe and effective. With fast-tracking, this time can be roughly halved. That means if a drug company were to come across a new compound that killed several strains of drug-resistant bacteria, it would take almost ten years before prescribers would have it available to them. At the very least, it would take five years. In the meantime, untold numbers of people could die from related infections.
Drug-resistant strains like MRSA are responsible for such lovely conditions as necrotizing fasciitis, or flesh-eating bacteria, as it is popularly known. Most people that end up with NF are otherwise-healthy individuals who somehow contracted it. This can happen as a result of soft tissue trauma (car accident, a cut or scrape, etc.) and it can be idiopathic, which means that its cause is unknown. The only cure for NF is to remove all of the compromised tissue. This can lead to amputated limbs or removing sections of the body. It’s not pleasant, and is just one of the common manifestations of drug resistant bacteria, and it happens to normal people: people like you and I just going about their daily lives. Of course there are risk factors that can increase your chances of infection, like diabetes mellitus and HIV, but they are hardly a requirement for infection.
In any case, a particularly disturbing press release today warns of drug-resistant bacteria gaining virulence. This means that aside from being able to resistant the antibiotics that we have today, they are also becoming more aggressive, spreading and killing faster than before. Once again, these are normal children that were infected.
[...]researchers at the University of Chicago describe three cases of rapidly progressive and ultimately fatal Staphylococcus aureus infections in small children.
Although all three children were previously healthy, the infection caused severe sepsis, rapid clinical deterioration and bleeding into the adrenal glands, a complication, known as Waterhouse-Friderichsen syndrome, that is usually associated with fulminant bacterial meningitis.
Two of the three bacterial strains were resistant to standard antibiotics. In all three cases, the disease progressed so rapidly that neither standard nor alternative antibiotics had an effect.
“What we saw in these patients is not in the textbooks,” said Robert Daum, M.D., professor of pediatrics at the University of Chicago and senior author of the study. “This is the first time this unusual syndrome has been described in patients with a Staph infection.”
This latest news only adds to the problem of drug-resistant strains. Right now, there is no way of beating this particular strain because it moves too fast. And indeed, with current knowledge, the only solution seems to lie in creating a vaccine that can prevent humans from becoming infected, since it “is the only way we have ever truly beaten an infectious disease.”
It is never my intention to fear-monger, because I believe that crying “wolf!” is a bad idea unless there is really, truly a problem. And the problem of antibiotic resistant bacteria is a very real one, and it is something that the public needs to be more aware of. Many of the topics and things that I write about here on polyscience are largely fluff stories in that they’re simply interesting or cool, and don’t have much of an impact on people. But I believe this is not one of those fluff pieces.
“Hobbit species” called into question
Many of you probably recall the news a year ago about a “new species” of human discovered in Indonesia. There was controversy then over whether it was a new species or simply a stunted human, but the debate was largely laid to rest when it was named a new species. That society was roughly 1m tall, and were thought to resemble hobbits in shape and size. Now, new studies are again calling into question this designation as a new species, claiming instead that the hobbits are actually modern humans who had their growth stunted by some unknown condition — probably microencephaly.
Homo floresiensis exhibits some differences in structure (aside from size) from modern humans, such as premolars with two roots instead of one. Once again, though, microencephaly is being claimed as the cause of the small humans rather than speciation.
Brain size also figures into this assertion, because halving the size of a human would theoretically cut brain size by only 15%. A normal human has a brain size of approximately 990cc. So a “hobbit” should have a brain that’s about 750cc. Instead, it was only 400cc — which means that the brain-size corresponds to a creature roughly the size of a meerkat. Of course, geographical isolation is often the cause of evolutionary divergence, so seeing an abnormality like this in an isolated group wouldn’t be entirely surprising. Corroborating the brain-size issue, a skull with a brain matching floresiensis’s size has been found in the vaults of London’s Royal College of Surgeons. That person had microencephaly.
As it stands now, Homo floresiensis is still its own species, and it is likely that it will remain that way until conclusive evidence pointing to its being Homo sapiens is found. Dissimilarities such as the premolar issue are genetic differences not to be lightly disregarded. Whatever your view is, expect H. floresiensis to be in the news more over the coming months and years.