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Members of a tribe in Papua New Guinea has evolved resistance to a affliction similar to mad cow disease (called Creutzfeldt Jakob disease, or CJD, in people). How did they do it? Cannibalism, according to a study in the New England Journal of Medicine.

The Papua New Guinea variant is called kuru, and it was a disaster there. When members of the Fore people in Papua New Guinea died, others would eat the dead person’s brain during funeral rituals as a mark of respect. Kuru passed on in this way killed at least 2500 Fore in the 20th century until the cause was identified in the late 1950s and the practice halted [New Scientist].

The scientists compared DNA samples of about 3,000 living Fore people, some of whom had participated in the old rituals, to 152 samples of stored DNA from Fore that kuru killed. They looked at the genes for prions, ordinary brain proteins that take on a misfolded shape in prion disease such as CJD and kuru. They found a mutation called G127V that protected people from kuru. Only people who ate brains and survived have it, they found [Reuters].

The discovery excited scientists with the possibility of understanding and even treating other prion diseases, like CJD. And British neurologist John Hardy exemplified the scientific glee at seeing human evolution happen in such a short time. “It’s fantastic demonstration of natural selection… In Papua New Guinea kuru became the major cause of death, so there was a clear survival advantage and the selection pressure was enormous” [BBC News].

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Image: D. Carleton Gajdusek

DeCode Genetics, a genome sequencing and drug development company, found out the hard way that predicting disease risk simply by reading someone’s genes isn’t so straightforward. On Tuesday, deCode filed for chapter 11 bankruptcy protection in Delaware. The company’s financial problems have also raised some troubling questions about genetic privacy.

DeCode’s mission was to uncover genetic risk factors for common diseases and to develop personal genome scans so individuals could learn their risk. DeCode quickly became the leader in the worldwide race to identify the causes of common disease. The company’s researchers discovered mutations linked to schizophrenia, heart disease, diabetes, prostate cancer and many other illnesses. Its approach was to identify the mutations first in Icelanders and then to confirm them in other populations [The New York Times]. Iceland was seen as an ideal spot for genetic studies, because the population was fairly isolated and the country has excellent medical and genealogical records. However, the company’s early successes did not translate into dollars, in part because the mutations they found only account for a small percentage of the overall incidence of a given disease.

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Toys, refrigerators, washing machines, socks—more and more products contain silver nanoparticles. It’s no wonder: These particles, which measure less 100 nanometers (smaller than a single HIV virus), can kill microbes on contact. But, researcher Darin Furgeson says, nanosilver can also escape into ecosystems and cause serious damage to fish embryos. Furgeson’s team published its results in the journal Small.

In one new experiment, Furgeson, a professor of pharmaceutical sciences, exposed zebrafish embryos to silver nanoparticles in a laboratory, and found that some died and others were left with dramatic mutations. “Some of the fish became extremely distorted, almost making a number nine or a comma instead of a linear fish,” he said [Scientific American]. Eyes, tails, and other body parts turned out malformed in the fish that survived.

Just how much nanosilver gets into the environment? A separate study from Environmental Science & Technology washed nine kinds of nanosilver-containing textiles, including some “anti-bacterial and anti-odor socks” that are already on the market. The researchers found that anywhere from less than 1 percent to as high as 45 percent of the silver came out in the first wash. Most of the silver was in the form of coarse particles of greater than 450 nanometers, suggesting that mechanical stress in the washing machine was responsible for most of the release [The New York Times], and that the nanoparticles might have aggregated to reach that size.

Those nanoparticles flushed out by a washing machine can end up in both fish habitats and drinking water supplies. Furgeson says his fish experiments could help show whether nanosilver is a health concern for humans, too. “Zebrafish have similar tissues and organs to us,” Furgeson said. “They don’t have lungs, but they do have a liver, kidneys and heart – though it is only two chambered – and they have a blood-brain barrier” [Scientific American].

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Image: Wiki Commons / Kristof vt

The elites of ancient Egypt had money, power, divine status in the case of the pharaohs, and also heart disease. In a study in today’s issue of The Journal of the American Medical Association, a team of researchers reports performing x-ray scans of 20 Egyptian mummies and finding them rife with cardiovascular disease like clogged arteries, one of the commonest ailments in modern American society.

On a visit to the Museum of Egyptian Antiquities in Cairo, one of the researchers had been intrigued by a nameplate on the remains of Pharaoh Merenptah, who died in 1,203BC. The plate said the pharaoh died at the age of 60 and suffered diseased arteries, arthritis and tooth decay [The Guardian]. So the scientists obtained permission to scan that mummy and others in the museum collection.

The common people of ancient Egypt weren’t mummified; only elites like royal families, their nursemaids, and priests got such a treatment. The elites ate salted fish, bread, and cheese like everyone else, but they also dined on rich foods such as cow, sheep, and goat meat, as well as honey and cakes with butter, says Abdel Nureldin, a professor of Egyptology at Cairo University, who worked on the investigation. At the same time, virtually no one in ancient times was sedentary, and that may have helped counteract their fatty diets [ScienceNOW Daily News].

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It’s been a bad month for chemicals and masculinity. Last week 80beats covered the discomforting link found between the chemical bisphenol A (BPA), which is found in any number of consumer products, and erectile dysfunction. Now the villains are phthalates, chemicals used to make plastics softer and more flexible. A new study in the International Journal of Andrology has raised a storm of concern that prenatal exposure to these chemicals could make boys less masculine in their play preferences.

Phthalates, which block the activity of male hormones such as androgens, could be altering masculine brain development, according to Shanna H. Swan, a professor of obstetrics and gynecology at the University of Rochester Medical Center and lead author of the new report [Los Angeles Times]. To test whether that link extended into behavior, Swan’s team tested women for phthalate levels midway through their pregnancy and then checked back in on the children four to seven years later.

The researchers asked parents to report their children’s patterns of play, but they knew they also had to separate any potential phthalate effect from the “nuture ” side of question. To determine how parental views might sway behavior, parents completed a survey that included questions such as, “What would you do if you had a boy who preferred toys that girls usually play with?” They were asked to respond with whether they would support or discourage such behavior, and how strongly [TIME].

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Don’t let anyone treat you badly because of your genes. As of this weekend, it will be against the law.

The Genetic Information Nondiscrimination Act (GINA) prevents both employers and insurance companies from requiring genetic tests or from using your family’s medical history against you. The biggest change resulting from the law is that it will–except in a few circumstances—prohibit employers and health insurers from asking employees to give their family medical histories. The law also bans group health plans from the common practice of rewarding workers, often with lower premiums or one-time payments, if they give their family medical histories when completing health risk questionnaires [The New York Times]. The law also bars employers from requiring genetic testing or using such information to make decisions on hiring, firing or promoting employees.

To alleviate the privacy concerns of people that have had genetic testing, Congress stepped in and passed GINA last year. The act takes effect Nov. 21 for all employers with 15 or more employees. It applies to group health insurers whose plan years begin on or after Dec. 7, and it took effect for individual health insurance plans last May. The act does not apply to life insurers. The act would ban a company from not promoting a 49-year-old to chief executive because it knew his father and grandfather died of heart attacks at age 50 [The New York Times]. It is still legal for employers to glean information about an employee’s medical history from family obituaries, or to inquire why an employee missed work to care for a sick relative under the Family Medical Leave Act. However, it will now be illegal to use this information to somehow penalize the employee.

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Image: flickr / IRRI Images

Aficionados of 3AM Vodka, Max Fury, and Slingshot Party Gel, take heed! The Food and Drug Administration is casting a wary eye on your classy energy drinks. The federal agency has requested proof from the drink manufacturers that these combinations of caffeine and alcohol are, in fact, safe to drink. The FDA never has approved the addition of caffeine to an alcoholic beverage, and a task force of state attorneys general and other officials has urged the agency to scrutinize the combination. The task force argues that the caffeine can mask the intoxicating effects of alcohol, possibly leading to an increase in drunk driving, sexual assault and other destructive behavior [Los Angeles Times]. Since the FDA never approved the drinks in the first place, the burden of proof falls on the manufacturers, and now the FDA is forcing their hands.

And the FDA isn’t joking around. Companies including Diageo North America Inc., Constellation Brands Inc. and United Brands Co. were told that unless they could provide evidence of safety, the agency will “take appropriate action to ensure that these products are removed from the marketplace,” according to letters sent to the companies and released by the agency [Bloomberg]. The drink companies now have 30 days to respond to the request.

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Cocaine combined with capsaicin, an active ingredient in pepper spray, can be deadly, if research in mice is any indication.

In the early 1990s, anecdotes of people dying after being doused with pepper spray puzzled researchers, until autopsies revealed many were on cocaine at the time. To look for a link between the two substances, a research team injected cocaine, capsaicin or both at once into the abdomens of several groups of about 30 mice. Injections allowed them to control the dose of capsaicin the mice received, which wouldn’t have been possible if the mice were simply sprayed [New Scientist]. Equal doses of cocaine plus capsaicin killed about half the mice, compared to cocaine alone, which killed just a few. And a dose of cocaine high enough to kill half the mice on its own killed up to 90 percent when combined with capsaicin.

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A gene therapy treatment intended to reverse muscle weakness appears to restore muscle mass in monkeys, raising hopes that doctors may soon be able to treat this condition in humans with degenerative diseases like multiple sclerosis and muscular dystrophy. Scientists injected a gene into the monkeys’ thighs that causes cells to produce human follistatin, which interferes with another compound called myostatin. Myostatin breaks down muscle, so in theory adding follistatin should encourage muscles to grow [Reuters].

And grow they did. Within three months the monkeys’ thigh muscle mass increased, and the effect lasted for 15 months, according to the research published in the journal Science Translational Medicine. (Not quite the same effect as the whippet turned hugely muscular by a natural genetic defect.) The relatively long-lasting effect is promising for researchers looking to treat lifelong conditions such as multiple sclerosis and muscular dystrophy. The researchers say the treatment was safe and that no other organs were affected.

But there could be a downside to this promising work–some experts are asking whether this therapeutic technique could be used by unscrupulous athletes looking to tweak their genetics and to build stronger muscles. The drugs companies Amgen and Wyeth have already begun testing myostatin inhibitors in humans and such studies have already prompted fears about the potential for myostatin inhibitors to be abused by athletes hoping to gain the competitive edge. If gene therapy can achieve similar outcomes in humans, such modifications will be even harder to detect [New Scientist]. The World Anti-Doping Authority has banned gene doping in athletic competitions for obvious reasons, even though there’s no evidence that any athletes are tinkering with their genes.

Of course there wouldn’t be: If some jock were gene doping, there would be no way to detect it.

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Image: Wikimedia Commons / Muhammad Mahdi Karim

It started as an observation in a Seattle cancer ward, where oncologist Marc Chamberlain noticed that his male patients were often receiving steadfast support from their wives, while his female patients often didn’t have husbands hovering at their bedsides. Based on this anecdotal evidence, Chamberlain decided to investigate divorce rates among couples where one person had recently been diagnosed with a serious illness. His findings raise troubling questions about the loyalty of the male sex.

The study included diagnoses of both cancer and multiple sclerosis and found an overall divorce rate of nearly 12 percent, which is similar to that found in the normal population. But when the researchers looked at gender differences, they found the rate was nearly 21 percent when women were the patients compared with about 3 percent when men got the life-threatening diagnosis. The researchers suggest men are less able to commit, on the spot, to being caregivers to a sick partner, while women are better at assuming such home and family responsibilities [LiveScience]. However, the study did find that the divorce rate was lower in longer marriages.

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A chemical commonly found in plastics that has recently fallen under intense scrutiny by public health officials has now been linked to impotence. During a five year study, scientists followed 634 male Chinese factory workers who were exposed to high levels of the chemical bisphenol A (BPA) on the job and compared their sexual health with that of similar Chinese factory workers not exposed to BPA. The men handling BPA were four times as likely to suffer from erectile dysfunction and seven times as likely to have difficulty with ejaculation [Washington Post]. The study (PDF), published in the journal Human Reproduction, marks the first time sexual dysfunction has been linked to BPA exposure.

To be fair, the workers were exposed to BPA levels that are 50 times greater than the average U.S. man faces, so scientists can’t say how smaller amounts of the chemical will affect sexual health. However, the chemical resembles the hormone estrogen and that’s fueled worries that even very small amounts of BPA can cause harm [NPR News]. The feds are determined to get to the bottom of the issue and have pledged $30 million to researchers over the next two years in an effort to finally settle the question of whether BPA is safe.

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Many medical devices come equipped with wireless communication systems these days, allowing doctors to customize their operations or to see their patents’ information. But fitting pacemakers or implanted defibrillators with WiFi also opens the door to hackers‘ attacks. Hackers could potentially steal personal information, remotely drain batteries, or cause a dangerous malfunction, so researchers are working on ways to block them. The approach relies on using ultrasound waves to determine the exact distance between a medical device and the wireless reader attempting to communicate with it [Technology Review]. The plan is to only allow access to a medical device from wireless reading devices within 10 feet, and only then after a series of authentication steps. However, in the event of an emergency, the medical device would grant access to anyone within a few inches of the device. In other words, to anyone close enough to assist.

The research team also has to consider how much power their security measures will drain from the devices, which is a not-so-trivial point for a  battery-operated pacemaker. But Claude Castelluccia, who was involved with designing the security system, said that because the device won’t respond to requests that come from outside the predetermined distance, it would also be harder for an attacker to wear down the battery by forcing it to process one request after another [Technology Review]. To test their system, researchers recently implanted a medical device in the stomach of a cow, and they’re currently shopping their patented technology to potential developers.

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Image: flickr / library_mistress

Our long national nightmare is over: At last, scientists can make rabbit penis spare parts.

In the Proceedings of the National Academy of Sciences, researchers led by Anthony Atala published the results of their successful attempt to engineer new corpora cavernosas, the column of tissue that engorges with blood during male arousal, for male rabbits. Other procedures can partially restore function to a damaged phallus, and Atala’s team has previously shown they could replace a small portion of the tissue (they had up to a 50 percent success rate in rabbits) [Scientific American]. This, however, was the first time they totally replaced corpora cavernosas.

Atala is best known for developing a technique in which cells are taken from an organ and sprayed onto a frame made of collagen, the primary structural protein in animal tissue. The structure is then bathed with growth-stimulating compounds and kept in an oven that duplicates the body’s temperature and chemical composition. Given these starting conditions, natural biology does the rest [Wired.com].

In this experiment, the team surgically removed the corpora cavernosas of 12 rabbits, and replaced them with new “scaffolds” built through this technique. The tissue took hold, and copulation ensued at stereotypical rabbit pace. Every one of the revitalized dozen attempted to mate within a minute of being introduced to females; four became fathers.

The Wake Forest research contains the standard caveat: No, the technique isn’t ready for humans yet. But when it is, look out. Such methods could potentially aid men who just want to enhance their normal penises, rather than repairing any damage. “Our intent and the goal of our work is to provide a solution for men who need penile erectile tissue for medical reasons…. Of course, you cannot control how the technology is used in terms of what patients want” [LiveScience], says Atala.

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Image: flickr/Gidzy

If NASA ever wants to send astronauts on long-term space flights, it needs to know how radiation will affect the crew. Testing humans obviously isn’t going to happen, so NASA is funding a round of experiments to study how radiation effects monkeys, the first time monkeys have been used as test subjects by NASA in decades. The point of the experiments is to understand how the harsh radioactive environment of space affects human bodies and behavior and what countermeasures can be developed to make long-duration spaceflight safe for travelers beyond Earth’s protective magnetic shield [Discovery News]. The monkey studies will advance previous radiation experiments with rats and mice and will focus on how radiation affects the monkeys’ central nervous system.

Researchers will expose 18 to 28 squirrel monkeys with a small dose of radiation, similar to what astronauts would receive on a round trip flight to Mars. The monkeys, previously trained to perform a variety of tasks, will be tested to see how the exposure affects their performance [Telegraph] at different times after exposure to gamma rays. The monkeys will not be killed during the experiments, and after testing staff and veterinarians will look after them for the rest of their lives at Harvard Medical School’s McLean Hospital in Boston.

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News that an Iowa cat has been diagnosed with swine flu has sparked a new round of concerns, as pet-owners worry both that their furry companions could get sick, and that their pets could pass the virus on to other humans. The 13-year-old, mixed-breed cat showed the symptoms of lethargy, sneezing and coughing typical to sick cats [ABC News]. The veterinarians who treated him say that several people in the cat’s home had been experiencing flu-like symptoms, and lab work confirmed that the feline had the H1N1 virus.

Happily, the cat is expected to make a full recovery. But both vets and public health officials are rushing to reassure the public that one sick cat probably does not indicate a coming crisis. While it’s possible that more cats will be diagnosed with the swine flu, vets point out that the virus was circulating for more than six months before the first cat case was discovered, indicating that the virus probably doesn’t jump from species to species very easily. Doctors also note that there’s very little chance that a cat will spread the virus to humans: Even when inter-species transmissions do occur, the H1N1 virus seems more likely to move from humans to animals, rather than the other way around [HealthDay News].

There have been no reported cases of dogs catching the virus, but there is one type of pet that is known to be vulnerable. Ferrets are generally susceptible to the seasonal flu, and the AP reported Wednesday that H1N1 infection has been confirmed in two ferrets, one in Nebraska and the other in Oregon. “Not only can they be infected with the flu but they are clearly able to transmit the flu back to people,” Treanor said [HealthDay News]. But the bottom line appears to be: Unless you’re a ferret-owner, you probably have nothing to worry about.

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Image: flickr / theogeo