Smithsonian.com

A new study involving lab mice could bring a breakthrough in treating Alzheimer's. Image courtesy of Flickr user Rick Eh?

Alzheimer’s disease damages brain tissue in a variety of ways, but one of the most important seems to be the buildup of “plaques.” The deposits contain protein called beta-amyloid. Normally, beta-amyloid is produced and then removed at a more or less constant rate, but not in individuals with Alzheimer’s disease.

Beta-amyloid is normally removed from the brain with the help of a molecule called apolipoprotein. One version of this molecule, ApoE, increases a person’s risk of Alzheimer’s and appears to be linked to beta-amyloid buildup.

Meanwhile there is bexarotene, a chemical used in cancer treatments (officially for cutaneous T-cell lymphoma but unofficially for some other cancers). Researchers at Case Western Reserve University School of Medicine used bexarotene in mice that have a condition similar to human Alzheimer’s to change the relationship between ApoE and beta-amyloid. The drug caused plaques to be removed from much of the neural tissue. The behaviors of the mice on learning and memory tasks also changed in ways indicating that the effects of the Alzheimer’s-like condition was reversed, at least partially. A mere 72 hours of treatment with bexarotene “cured” misdirected nesting behavior and caused improvement in other tasks. Olfactory sense improved in some of the mice over a nine-day period.

There are reasons to be very positive about this result, but also reasons to be very cautious. Among the reasons to be cautious are:

• Mice are not humans, so there may be important but subtle differences in brain chemistry that will cause this treatment to not work the same way in humans.
• Although mice improved behaviorally, it is difficult to match mouse and human forms of “dementia,” so we must be cautious in interpreting the meaning of improvement in the mice.
• As far as I can tell, the effects of this treatment may be only short-term. Even though bexarotene has been used widely on humans, the dose and treatment approach needed for addressing human Alzheimer’s may be very different. It could even be dangerous or implausible.
• The ApoE contribution to Alzheimer’s is only one part of the disease. It may well be that the best-case scenario of a treatment based on this research would be only a partial cure, or only for some individuals.

Reasons to be optimistic include:

• The result seen in the mice was dramatic and fast. Half the plaques were removed in 72 hours, and over the long term, 75 percent were removed.
• Bexarotene is a drug already approved for use (in other areas of treatment) by the FDA, so the process of investigating this drug’s efficacy and safety is much more advanced than if it was some chemical not previously used on humans.
• Even if it turns out that this drug will not be usable on humans to treat this condition, a result like this strongly indicates a path for further research to develop similar treatments.

The researchers are optimistic. Paige Cramer, first author of the study, noted in a press release, “This is an unprecedented finding. Previously, the best existing treatment for Alzheimer’s disease in mice required several months to reduce plaque in the brain. Research team leader Gary Landreth notes that “this is a particularly exciting and rewarding study because of the new science we have discovered and the potential promise of a therapy for Alzheimer’s disease. We need to be clear; the drug works quite well in mouse models of the disease. Our next objective is to ascertain if it acts similarly in humans. We are at an early stage in translating this basic science discovery into a treatment.”

A lot of research related to disease seems to be reported in press releases and elsewhere with more optimism than deserved, but in my opinion this is a case where the new research is more closely linked to potential treatment than is often the case. Keep an eye on this story!

Cramer, Paige E. John R. Cirrito, Daniel W. Wesson, C. Y. Daniel Lee, J. Colleen Karlo, Adriana E. Zinn, Brad T.
Casali, Jessica L. Restivo, Whitney D. Goebel, Michael J. James, Kurt R. Brunden, Donald A. Wilson, Gary E. Landreth. (2012). ApoE-Directed Therapeutics Rapidly Clear β-Amyloid and Reverse Deficits in AD
Mouse Models. Science. Science Express 9 February 2012. DOI: 10.1126/science.1217697

Cats and earthquakes were popular subjects this year. (image courtesy of flickr user 37prime)

It’s that time of year when journalists and bloggers put together their reviews of the past 12 months. But the list below is unlike any other. You may have noticed that Surprising Science tends to cover science a bit differently than other blogs and publications do. Combine that with a diverse (and, of course, fabulous) readership, and you’ve got an interesting list of most-read stories for the year. (If you’re looking for a more traditional 2011 retrospective, we recommend the lists from Discover, Scientific American and Science.)

#10 Earthquake in Washington, D.C.: On August 23, the Smithsonian offices, along with a good portion of the Northeast, shook due to a magnitude 5.8 earthquake in Mineral, Virginia. In a weird coincidence, I had been researching earthquakes in unexpected places when the quake took place, and so people in my office jokingly blamed me for the incident.

#9 14 Fun Facts About Chickens: Following the earthquake and Hurricane Irene, we took a break from natural disasters with weird chicken facts. My favorite? That a female bird can eject the sperm of a rooster if she decides she doesn’t want his chicks.

#8 The Science Behind the Japanese Earthquake: On the morning of March 11, we woke up to news of a powerful earthquake off the coast of Japan. That shaking, however, would soon be overshadowed by the devastating tsunami and nuclear disaster that followed.

#7 Examining Telecommuting the Scientific Way: Unfortunately this post did not have the result I’d hoped, and I’m still not allowed to telecommute. (But if anyone has been successful in using these arguments, please let us know in the comments below.)

#6 The Secret Lives of Feral Cats: After a study in which scientists tracked feral kitties, we weighed in on the question of whether it was better to trap the cats, spay/neuter them and release them back into the wild or, as some advocate, euthanize any found. The blog came down on the side of catch and release, but we discovered many readers who have a serious hatred for these felines.

#5 The Curious World of Zombie Science: We examined an interesting trend in science, the study of human zombies, including computer models of the spread of the zombie disease, potential ways zombies could be created and how math could save you from a zombie attack.

#4 The Myth of the Frozen Jeans: Levi’s and the New York Times claimed that freezing your jeans would kill the germs that make them smell. Scientists who study bacteria disagree.

#3 Five Historic Female Mathematicians You Should Know: Our list, a companion to a top ten list of historic female scientists, included the creator of the world’s first computer program and a contemporary of Albert Einstein.

#2 Life Without Left Turns: A study that found that intersections constructed to eliminate dangerous left turns were more efficient than traditional intersections added to my convictions that getting rid of left turns would be a good thing. But not all my readers agreed.

And #1 The Glow-in-The-Dark Kitty: A story about Mayo Clinic researchers who created a fluorescing cat as part of their studies on feline HIV, which they hope would lead to insight on human HIV and AIDS, sparked a debate in the comments about the ethics of the research.

Do you freeze your jeans? (courtesy of flickr user fogindex)

Levi Strauss advises freezing your jeans to kill the germs that make them smelly, thereby saving the water you’d use in washing them.

Don’t bother, says Stephen Craig Cary, a University of Delaware expert on frozen microbes, who wrote to us from Antarctica.

Most of the bacteria on your jeans probably started off on your own body. Since these critters are happiest living at the temperature of human skin, “one might think that if the temperature drops well below the human body temperature they will not survive,” Cary writes, “but actually many will. Many are preadapted to survive low temperatures.” And it takes only one survivor to repopulate your jeans when they warm up.

“I would suggest that you either raise the temperature to 121 degrees Celsius [250 degrees Fahrenheit, the temperature used for sterilization] for at least 10 minutes,” Cary writes, “or just wash them! The latter surely is the best alternative to save energy.”

Julie Segre of the National Human Genome Research Institute, who studies the skin’s microbiome, seconds the washing recommendation. “The bacteria that would live on your jeans [are likely feeding] on the sloughed skin and the dirt nutrients [on the jeans rather] than the jeans themselves, so detaching the sloughed skin could reduce the microbial load of your jeans,” she says. In her opinion, removing the dirt and the sloughed skin is more important than removing any bacteria, though she warns that she may have “just transitioned from speaking as a scientist to speaking as a mother.”

How often you wash your jeans may depend on how comfortable you are with the growing amount of dirt and sloughed skin on the fabric; the bacterial load doesn’t seem to be much affected by how often you go between washings. A somewhat unscientific experiment by a Canadian student found little difference in the bacterial load between one pair of jeans worn for 15 months without washing and another pair worn for 13 days.

So, sorry Levi’s, freezing our jeans sounded like a great idea, but it’s probably not doing anything more than taking up space better left for ice cream.

A group of scientists and statisticians led by the University of California at Berkeley set out recently to conduct an independent assessment of climate data and determine once and for all whether the planet has warmed in the last century and by how much. The study was designed to address concerns brought up by prominent climate change skeptics, and it was funded by several groups known for climate skepticism. Last week, the group released its conclusions: Average land temperatures have risen by about 1.8 degrees Fahrenheit since the middle of the 20th century. The result matched the previous research.

The skeptics were not happy and immediately claimed that the study was flawed.

Also in the news last week were the results of yet another study that found no link between cell phones and brain cancer. Researchers at the Institute of Cancer Epidemiology in Denmark looked at data from 350,000 cell phone users over an 18-year period and found they were no more likely to develop brain cancer than people who didn’t use the technology.

But those results still haven’t killed the calls for more monitoring of any potential link.

Study after study finds no link between autism and vaccines (and plenty of reason to worry about non-vaccinated children dying from preventable diseases such as measles). But a quarter of parents in a poll released last year said that they believed that “some vaccines cause autism in healthy children” and 11.5 percent had refused at least one vaccination for their child.

Polls say that Americans trust scientists more than, say, politicians, but that trust is on the decline. If we’re losing faith in science, we’ve gone down the wrong path. Science is no more than a process (as recent contributors to our “Why I Like Science” series have noted), and skepticism can be a good thing. But for many people that skepticism has grown to the point that they can no longer accept good evidence when they get it, with the result that “we’re now in an epidemic of fear like one I’ve never seen and hope never to see again,” says Michael Specter, author of Denialism, in his TEDTalk below.

If you’re reading this, there’s a good chance that you think I’m not talking about you. But here’s a quick question: Do you take vitamins? There’s a growing body of evidence that vitamins and dietary supplements are no more than a placebo at best and, in some cases, can actually increase the risk of disease or death. For example, a study earlier this month in the Archives of Internal Medicine found that consumption of supplements, such as iron and copper, was associated with an increased risk of death among older women. In a related commentary, several doctors note that the concept of dietary supplementation has shifted from preventing deficiency (there’s a good deal of evidence for harm if you’re low in, say, folic acid) to one of trying to promote wellness and prevent disease, and many studies are showing that more supplements do not equal better health.

But I bet you’ll still take your pills tomorrow morning. Just in case.

This path has the potential to lead to some pretty dark times, as Specter says:

When you start down the road where belief and magic replace evidence and science, you end up in a place you don’t want to be. You end up in Thabo Mbeki South Africa. He killed 400,000 of his people by insisting that beetroot garlic and lemon oil were much more effective than the antiretroviral drugs we know can slow the course of AIDS. Hundreds of thousands of needless deaths in a country that has been plagued worse than any other by this disease.

If you don’t think that can happen here, think again. We’re already not vaccinating children against preventable diseases, something that will surely lead (and probably already has led) to lives lost. We have big problems to address in the coming decades—even greater changes to temperature, weather and water as the planet warms; a growing population—and we need to start putting our trust back into science, into the process that has brought us to where we are today, with longer lives, cleaner water and skies, more efficient farming. Because you have to admit, this is a pretty great time to be alive and it’s science that got us here.

Does this Aston Martin V8 Vantage make your mouth water? (courtesy of flickr user Destinys Agent)

If you think about it, some of the phrases we use to express desire for inanimate, non-food items are pretty weird. We “drool” over cars. Our “mouths water” at the sight of a pile of money. Salivating makes sense when we’re talking about food—after all, salivation is part of the anticipatory phase of digestion, and saliva moistens our food to assist swallowing—but why would we drool over something we can’t eat? We do, though, as shown in a new study in the Journal of Consumer Research.

David Gal, a marketing professor at Northwestern University, conducted two experiments, each time measuring saliva production. In the first he started off with a writing assignment, asking the participants to write about either a time they felt they had power or a time when they lacked power. Those two groups were then split and shown either images of money or, as a control, office supplies. Only the people who had been assigned to write about a time when they lacked power salivated at the sight of money, Gal found. The assignment had primed those individuals to find money to be more attractive. (Office supplies, not shockingly, had no effect.)

In the second experiment, which focused on the responses of men only, the participants were primed with what Gal calls a “mating goal.” Half had to choose a picture of a woman and write about an imagined date with her; the other half had to choose a picture of a barbershop and write about an imagined haircut. The images of money and office supplies were then replaced with pictures of sports cars and fastening tools. Again, the participants who had been primed to think about what they lacked salivated over the photos of the cars. (Guys really do think that sports cars make them more attractive to girls.) “These findings show that exposure to a material reward cue stimulates salivation when the reward value is high,” Gal writes.

OK, so under the proper circumstances, we might drool over a non-food item. But why would this be? As Gal notes, “Salivation to material reward is not of any obvious function.” He has two theories, though: One, that we are conditioned from early in life to associate material rewards with food. More likely, though, might be number two, that salivation is a side-effect of the natural reward system. If there’s just one system in our brains that rewards us for everything—from drugs to money to chocolate chip cookies—then it makes sense that we could salivate over any of those things. As Jonah Lehrer writes on the Wired blog Frontal Cortex:

Although our dopamine neurons evolved to process and predict biological necessities, they’ve since learned to embrace a more catholic set of desires, so that pieces of green paper filled with pictures of dead presidents get them very excited. While relying on a single pathway to process all of our rewards normally works quite well—the dopamine reward pathway is some well-tested cognitive software, since the same basic code is present in nearly every mammal—it does lead to a few unintended side-effects. Just ask a drug addict, or that man who starts to drool whenever a Ferrari drives by.