Charles Darwin may have been right in worrying that the ill health that plagued his family were a result of inbreeding. Darwin didn’t only marry his first cousin, Emma Wedgwood–in fact, the Darwins and the Wedgwoods made a habit of intermarrying (Darwin’s maternal grandparents were also third cousins). Now a new study, which crunched the numbers on first-cousin marriages over four generations of the two dynasties, suggests that his children had an elevated risk of health problems.
The degree of inbreeding among Darwin’s children, while not excessive, was enough to increase the risk of recessive diseases — ones that occur if a harmful version of a gene is inherited from both parents. Three of his 10 children died before age 10 — 2 of bacterial diseases. Childhood mortality from bacterial infections is associated with inbreeding. So, too, is infertility, and three of Darwin’s children who had long marriages left no children [The New York Times].
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It’s not that teenagers aren’t trying to learn. (Well, OK, some of them definitely aren’t trying.) But the distractions that come with being a teenager are exacerbated by the fact that teens just don’t learn as quickly as either young kids or adults, and a new study of mice that appears in Science points to specific brain changes that might help explain why.
Seeking to study spatial learning during puberty, the team devised a relatively complex task (at least for a mouse) that requires learning how to avoid a moving platform that delivers a very mild shock [TIME]. While the prepubescent mice picked up on what to avoid pretty quickly, as did adult mice, pubescent mice took considerably longer to figure it out. The key to these differences was what study leader Sheryl Smith saw in the brains of these mice.
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The Iraq war and its aftermath have left physical and psychic wounds on both local residents who lived through the American invasion and many U.S. soldiers. But anecdotal reports suggest that another demographic may have suffered as well: unborn babies. Doctors in Fallujah, Iraq have reported a high number of children born with birth deformities ever since the massive battle between Iraqi insurgents and U.S. forces that raged there in 2004.
While no medical studies have been done or official reports have been issued, many Fallujah locals suspect that U.S. weaponry used in the assault has left a lingering effect.
A debate is expected to come up in the British parliament sometime next week on the subject. The call for debate came up after the latest report by BBC’s John Simpson, in which an Iraqi pediatrician said she was seeing two to three deformed babies each day; most of the children had cardiac complications. The doctor clarified that while she didn’t have any official figures, she had noted an increase in the number of cases since the American invasion. The current level of cardiac birth defects in Fallujah, said the BBC, is 13 times higher than that in Europe.
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Louise Brown, the first baby conceived through in vitro fertilization, will be turning 32 this year, and most people born through IVF are still younger than 30. While the technique has become commonplace for would-be parents struggling with fertility problems, doctors note that the long-term effects of the procedure still aren’t certain. Now, some scientists are saying they see slight differences in the DNA expression of people born via IVF, and that it’s possible they could be at higher risk for conditions like cancer or diabetes later in life.
Says lead researcher Carmen Sapienza said “By and large these children are just fine, it’s not like they have extra arms or extra heads, but they have a small risk of undesirable outcomes” [The Guardian]. Rather, the team found a very subtle impact. In 75 IVF babies and 100 naturally conceived ones, they examined 700 genes that particularly interested the researchers because they are linked to fat cell development, insulin signaling, and other functions associated with diseases for which people tend to be at higher risk as they age. The scientists checked DNA methylation, a modification to DNA which affects gene expression, and found that 5 to 10 percent of IVF babies had abnormal patterns of methylation.
Sapienza’s team published the study in October in Human Molecular Genetics, but his work is picking up attention after he spoke at the American Association of the Advancement of Science meeting in San Diego.
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When your kid isn’t in class, he/she is probably listening to an iPod, flipping TV channels, or switching between tabs on their computer, which means they may be juggling between Myspace, Facebook, and YouTube–in other words, kids today are staying hyperconnected and wired through their waking hours. That reality is confirmed by a new study done by the Kaiser Family Foundation, which reveals that if your kids are awake, they’re probably online [The New York Times].
In the third of a series of large-scale national surveys, the Kaiser Foundation study found that kids between the ages of 8-18 years now spend an average of 7 hours, 38 minutes per day using entertainment media. That adds up to more than 53 hours of entertainment consumption in a week. And this does not include the time kids spending texting or talking on their cell phones.
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In very rare cases, the womb is a dangerous place for a developing fetus. Researchers have found that pregnant women can pass on cancer cells to their unborn babies, if those cancer cells carry a particular genetic mutation. The new study resolves a longstanding puzzle, because in theory any cancer cells that manage to cross the placenta into the baby’s bloodstream should be targeted for destruction by the child’s immune system. But there are records of 17 cases of a mother and baby appearing to share the same cancer – usually leukaemia or melanoma [BBC News].
In the study, which will be published in Proceedings of the National Academy of Sciences, researchers used a genetic “fingerprinting” technique to match the cancer cells found in a mother and baby. The case, involving a Japanese mother aged 28 and her daughter, revealed that both patients’ leukaemic cells carried the identical mutated cancer gene BCR-ABL1 even though the infant had not inherited this gene [The Times]. This meant that the child, who was diagnosed with cancer at the age of 11 months, could not have developed leukemia independently.
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To make one of the most sensitive diagnoses, hospitals might do well to call in a computer program. Researchers created a program that can sift through medical records and flag those patients who show signs of domestic violence. While emergency room doctors are always on the lookout for telltale signs, it may be hard to make the diagnosis from one or two isolated incidents. With this program, says lead researcher Ben Reis, “You are potentially able to detect high abuse risk years ahead of time: you don’t wait for a very bad thing to happen” [New Scientist].
Researchers first let the program scan through more than 350,000 medical records which included a substantial number of people who were eventually diagnosed as victims of domestic abuse, and asked the program to look for differences in their medical histories. The computer came up with a collection of risk factors that were highly associated with a future diagnosis.
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Amidst concerns over the safety of DEET, scientists are on the lookout for a new mosquito repellent. Now they may have found a way to keep biting insects at bay–by blocking their olfactory sense, according to a paper published in Nature.
Mosquitoes sense the presence of humans and animals by detecting the carbon dioxide we exhale with each breath. Researchers have found two compounds, 2,3-butanedione and 1-hexanol, that could keep the biters at bay by blocking the insects’ ability to detect this gas. Using these compounds could be advantageous because the amount of chemical required is relatively small…. Further, the chemicals themselves are not complicated to manufacture and are available through conventional sources. “From both perspectives, this adds up to a viable tool in tackling the problems like that of malaria in Africa” [Scientific American], says study coauthor Anandasankar Ray. Considering the number of diseases spread by insects such as mosquitoes–for example, 250 million people contract malaria each year–there’s a lot more at stake here than a few itchy bug bites.
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Birth rates have decreased by about 2 percent in 2008, the first year since the beginning of the decade that rates did not increase, according to statistics from the National Center for Health Statistics. Many experts speculate that this drop is due to the recession. Still, birth rate statistics have not yet been finalized, and some believe that a decrease in immigration could account for the decrease in births.
As any parent knows, children are expensive, so in a shaky economy, it makes sense that fewer people would be having them. “It’s the recession,” said [sociologist] Andrew Hacker… “Children are the most expensive item in every family’s budget, especially given all the gear kids expect today. So it’s a good place to cut back when you’re uncertain about the future” [New York Times]. Perhaps not coincidentally, the two states with the largest decrease in births–California and Florida–are also the ones that faced the biggest problems due to the housing crisis.
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Scientists seem to have finally put to rest a longstanding debate over itchiness: Is the urge to itch a sensation that is simply another interpretation of pain, or a separate feeling altogether? It turns out the two stem from different cells and neural pathways, according to a new study in Science.
To find out whether pain and itchiness are separate sensations, scientists injected mice with a neurotoxin. This toxin homed in on and killed cells that contained active versions of GRPR, a gene that is involved in the sensation of itchiness. (The same research group discovered this itch gene in 2007.) Afterward, the mice could no longer respond to any itchy stimuli. They didn’t flinch. They made no effort to scratch. But they did respond to pain just like other mice do [TIME], showing that the gene needed to be active to transmit itchiness, but not pain. It’s just one study, but it provides strong evidence that itchiness and pain are processed by separate neural pathways.
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An increasingly common surgical procedure for repairing spinal fractures might not be all it’s cracked up to be–in fact, the surgery had the same effect on patient’s pain as a placebo, two studies report in the New England Journal of Medicine.
The technique, called vertebroplasty, involves injecting medical cement into a fractured spine bone to strengthen it. More than 38,000 such procedures are done in the United States every year and the number has been [increasing] rapidly, nearly doubling from 2001 to 2005 [Reuters]. But the new studies showed that the procedure alleviated pain about the same amount as a placebo “surgery,” in which the physicians tapped on the spine and piped in the smell of cement to make groggy volunteer subjects believe they were receiving the real thing.
Researchers found that 36 volunteers who received sham surgery did just as well as 35 who got the real operation. A separate test, of 131 people at 11 medical centers, … also found that sham surgery produced a comparable degree of pain reduction and movement [Reuters].
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Powerful bug repellant DEET may do more than keep mosquitoes and other biting critters at bay–it might cause neurological damage in mammals, according to a study published in BioMed Central Biology.
Developed in 1946 by the U.S. Army, DEET has been used by the public for more than half a century to repel bugs like mosquitoes, along with the diseases they can carry. The new study, however, shows that DEET—aka N,N-diethyl-meta-toluamide—may be harmful for a variety of animal cells. In lab tests, it caused damage to mosquitoes, cockroach nerves, mouse muscles, and enzymes purified from fruit flies and humans. Applications of DEET slowed or halted the actions of the enzyme acetylcholinesterase. This enzyme hangs out between nerve and muscle cells, breaking down a messenger molecule after it has passed information from one cell to another. If this messenger isn’t properly recycled, it can build up and lead to paralysis [Science News].
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Few people enjoy being poked and prodded at the doctor’s office, but we usually assume that those unpleasantries are worth detecting a disease or disorder early on. Unfortunately, though, we might never hear about worrisome test results, according to a new study published in the journal Archives of Internal Medicine. Researchers found that about 7 percent of clinically significant test results are never reported to the patient or that the notification of patients is not documented, largely a result of medical information slipping through the cracks.
The researchers examined the records of 5,434 patients between the ages of 50 and 69 at 19 community-based primary care practices and an additional four academic medical care facilities. The patients were old enough to likely be developing conditions that warranted testing (such as for high cholesterol, impaired blood-sugar control, prostate cancer or waning liver function), but not so old as to be ill enough to make certain of these findings relatively unimportant. Patients’ records were reviewed for any of 10 types of blood tests and for three types of screening exams — mammography, Pap smears and occult blood assays of possible colon cancer. During a yearlong period, the participating practices had prescribed several thousand such tests [Science News]. The researchers found that physicians did not inform patients about abnormal test results about one out of 14 times, or around 7 percent of the time.
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Researchers may have finally figured out the mechanism of the tragic birth defects caused by thalidomide, the drug taken by pregnant women in the late 1950s as a remedy for nausea: It is thought to have inhibited development of new blood vessels at a crucial stage in the pregnancy.
Women usually took the drug at about five to nine weeks into their pregnancy to combat morning sickness, a specific window that lead researcher Neil Vargesson says “is crucial as that is when the limbs of babies are still forming…. The blood vessels involved in this process, at this stage of pregnancy, are still at an immature stage when they rapidly change and expand to accommodate the outgrowing limb” [BBC]. The most common birth defects caused by thalidomide were babies born with stunted or malformed limbs.
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The rate at which infants gain weight in the first six months of their lives is linked to those babies’ risk of becoming obese by age three, a new study has found. Researchers determined that sudden weight gain in early infancy was more important than how much a baby weighed at birth, the weight of the infant’s parents, or the number of pounds put on by the mother during pregnancy. “The perception has been that a chubby baby and a baby that grows fast early in life is healthier and all the baby fat will disappear,” said the paper’s lead author, Dr. Elsie Taveras…. “But [that] is not the case” [Chicago Tribune].
While the researchers note that early childhood obesity does not necessarily lead to obesity later in life, they say it does raise the risks. Obesity rates among U.S. children have doubled in the last 20 years, and almost a third of American children are either overweight or obese. The epidemic of obesity is linked to a host of health problems such as higher risks for heart disease, diabetes and cancer [Reuters].
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