People who look younger than their actual age have a longer life expectancy than those who look their age, according to Danish scientists.

To reach this conclusion, Kaare Christensen of the University of Southern Denmark and colleagues asked nurses, teachers-in-training and peers to guess the age of 1,826 pairs of twins from their photos.

The twins were at least 70 years old when they were photographed.
 
For all 3 assessor groups, perceived age of the twins was associated with their survival, even after adjustment for chronological age, gender, pre-existing medical conditions, cognitive abilities and socioeconomic status.

Furthermore, the bigger the difference in perceived age within the pair, the more likely it became that the older looking twin died first.

The authors even provided a possible physiological explanation for their finding: key pieces of cellular DNA known as telomeres, which predict the ability of cells to replicate, were also linked to perceived age, the group found.

Shorter telomeres are associated with more rapid ageing, and the scientists found that people who looked younger had longer telomeres.

Christensen suggested to the BBC that people who have had a tougher life are more likely to die early – and that their life is reflected in their face.

“It’s probably a combination of genes plus environment over a lifetime that are important,” said UK professor Tim Spector, who has been doing similar research on twins. “We are also finding this in our study.”

The write-up is in the British Medical Journal.

The radiation produced by CT scans performed in 2007 will cause 29,000 cancers and kill 14,500 Americans, according to a study published in the Archives of Internal Medicine. 

To reach this conclusion, Amy Berrington de Gonzalez and colleagues from the National Cancer Institute used a computer simulation to estimate the impact of the 70 million or so CT scans that were performed in the US that year (only 3 million were performed in 1980).

The scientists estimated that about a third of the future cancers will occur in people who were between the ages of 35 and 54 when they received their CT, and 15% of them will develop in people who were children or teens when the scan was performed.

About two-thirds of the new cancers will develop in women, since they are more vulnerable to radiation.

“There is a significant amount of radiation with these CT scans, more than what we thought, and there is a significant number of cancers,” Rita Redberg, the editor of the Archives of Internal Medicine, told the LA Times.

“While certainly some of the scans are incredibly important and life saving, it is also certain that some of them were not necessary,” Redberg added.

CT scans provide pristine images by combining data from multiple x-ray images. They can also expose patients to up to 400 times more DNA-damaging radiation than conventional chest x-rays. 

In another study, Rebecca Smith-Bindman and colleagues from UCSF found that radiation exposure varies almost 13-fold for different kinds of CT studies, from about 2 millisieverts for a routine head CT scan to 31 millisieverts for a scan of the abdomen and pelvis.

The average American receives about 3 millisieverts of radiation per year, a level not considered to be a health risk.

Drug induced increases in levels of the brain neurotransmitter norepinephrine can overcome memory problems and improve cognitive development in mice with genetically-engineered Down syndrome, according to scientists at Stanford.

Ahmad Salehi and colleagues postulate that similar interventions, if applied early enough in children with Down syndrome, might improve their cognitive development as well.
 
Their write-up appears in Science Translational Medicine.

In the article, Salehi’s group showed that drugs which enhanced norepinephrine signaling in the brains of the genetically engineered mice rapidly restored cognitive function, enabling them to handle simple challenges like building a nest.

The treated mice could make nests as well as normal mice. Untreated mice were unable to do so. The beneficial effects became apparent just hours after treatment was initiated. They waned quickly following discontinuation of the drugs.
 
Salehi’s genetically-engineered mice exhibited early degeneration of the locus ceruleus, a part of the brain that supplies norepinephrine to the hippocampus, which is involved with memory formation. The same findings have been demonstrated in humans with Down syndrome.

Several drugs that have been approved by the FDA for treatment of depression and ADHD have the same effects on brain norepinephrine levels as those used in the Stanford study. Because these drugs have proven to be safe in humans (though not infants), Salehi told BurrillReport he hoped his results would quickly lead to human trials.
 
Previous efforts to modify the course of Down syndrome with drugs have focused on acetylcholine, a separate neurotransmitter that also acts on the hippocampus.

Employees of Xe Services, formerly known as Blackwater Worldwide occasionally operated alongside CIA and Special Forces operatives during missions to kill or capture members of al-Qaeda and other undesirables in Iraq and Afghanistan, former government officials have told the Washington Post.

Such behavior would exceed the protective role assigned to Blackwater in a contract with the CIA, the sources said.

The missions were approved and planned by CIA officials. But when it came time came to carry out those raids, local CIA operatives delegated responsibilities to available personnel regardless of whether they were contractors or federal employees.

A former CIA official with experience in Middle East covert operations confirmed that such decisions would be “practical…there was no bench strength with either the CIA or Special Forces, so sometimes they would turn to contractors, who often had the same skills,” he told the Post.

Former CIA officer Robert Baer said that such arrangements would short-circuit normal chains of command that CIA and military personnel must abide by. “Once you cede your authorities, people are no longer restrained by regulations and federal law,” Baer said. 

Earlier this year, CIA Director Leon Panetta terminated several contracts with Blackwater, but the agency still relies on the firm to provide security for agency employees and assets.

Former Washington-based CIA counterterrorism officials said CIA headquarters was not aware of such actions. They confirmed that Blackwater employees engaged in firefights while protecting CIA officers undertaking lethal raids, but characterized these actions as defensive, not offensive.

Currently, 5 Blackwater guards are standing trial in federal court on manslaughter and other charges stemming from the killing of 14 Iraqi civilians in Baghdad in September, 2007. In a separate civil case, 70 Iraqi civilians are alleging that Blackwater engaged in “lawless behavior” and covered up killings.

Executives from Google, the Washington Post and New York Times have announced a new partnership to create living story pages, tools which they believe might revolutionize the way people find news on line.

The concept is to group developing stories about a particular subject on one Web page which automatically updates when new content is added.

“So much of what you see online today is a reflection of the way it’s told in newspapers,” Josh Cohen, senior business product manager for Google News told Post media critic Howard Kurtz. “They haven’t taken advantage of what the Web offers to tell news in a different way.”

The Post and Times could conceivably boost their rankings on Google by grouping stories in this manner. This could increase the likelihood that people will click on their stories, and that might translate into increased revenue for the beleaguered print giants.

The Times has established 5 living story pages covering Afghanistan, executive compensation, global warming, health care and swine flu. Meanwhile, The Post has launched 3, devoted to DC schools, health-care reform, and the moribund Washington Redskins.

The experimental story pages currently reside at Google Labs as the parties work out the kinks. The goal is to transfer the pages to the Web sites of the newspapers themselves.

“Over the coming months, we’ll refine Living Stories based on your feedback,” Google says in a blog posting. If the format gains traction, Google plans to offer it to any interested newspaper, magazine or Web site, at no charge.

Kurtz reports that the living story page concept grew from discussions last spring involving Google CEO Eric Schmidt and Donald Graham, CEO of The Washington Post Co. Later, Google began separate conversations with executives at the Times.

As scientists race to create an AIDS/HIV vaccine, few have asked whether people can be persuaded to take the jab in the event it someday becomes available.

To assess HIV vaccine acceptability among high-risk adults, Peter Newman and colleagues from the University of Toronto interviewed 1,164 adults that have visited sexually transmitted disease clinics, needle/syringe exchange programs, and community health/HIV prevention programs in Los Angeles.

During the interviews, participants were asked to rate the acceptability of eight hypothetical vaccines, which varied in their effectiveness, cost and side effect profile, and to discuss how each one would impact their use of condoms after receiving the vaccine.

The scientists found that many high-risk individuals would not accept the vaccine, no matter what its characteristics were. Vaccine effectiveness turned out to be the attribute most likely to drive vaccine acceptance, followed by side effects and out-of-pocket cost.

The scientists also found that nearly 10% of the at-risk adults in the study might be more prone to engage in unprotected sex after they were vaccinated. This is critical since initial HIV vaccines are probably going to be only partially effective in preventing HIV infection.
 
“Merely having a vaccine available doesn’t mean it gets to the people who need it—a fact that is evidenced by the issues we’re seeing now around H1N1 vaccines,” Newman told BurrillReport. “If we want HIV vaccines to be acceptable and accessible to people, we need to consider all of these factors before we have a safe and relatively effective vaccine on the market.”

Newman added that educational programs built to support any future HIV/AIDs vaccine would have to explain in lay terms how it worked and what scientists mean when talking about the efficacy of a vaccine.

The obesity epidemic has become a major public health concern. The phenomenon is typically attributed to changes in diet and lifestyle, and socioeconomic factors like poverty and poor education.

Genetic factors have been known play a role as well, but a recent study by UK-based scientists suggests they play much more prominent role, at least in a subset of people who become morbidly obese at a young age.

In the study, Sadaf Farooqi of the University of Cambridge and colleagues showed that many such kids are missing a large chunk of DNA, known as SH2B1, from chromosome 16.

The missing genetic code had been known to play a role in regulating weight and blood sugar levels. Kids with the chromosomal abnormality tended to overeat on a massive scale, and gain weight easily. 

To reach these conclusions, the scientists scanned the genomes of 300 morbidly obese kids in search of copy number variants (CNVs), which are lengthy strands of DNA that are either duplicated or missing.
The scientists compared their findings with information from healthy controls.

In their write-up, which appears in Nature, the scientists wrote, “we identified several rare copy number variants that were recurrent in patients but absent or at much lower prevalence in controls.”

“Part of chromosome 16 can be deleted in some families. People with this deletion have severe obesity from a young age,” Farooqi told Medical News Today: “One particular gene on chromosome 16 called SH2B1 plays a key role.”

The finding may have broad social implications, since it is common to blame parents or guardians for morbid obesity in kids. The scientists noted for example, that some kids in the study had been handed over to Social Services because their parents were assumed to have been deliberately overfeeding them.

Baby Boomers that are just now entering their sixties are likely to be more burdened by disabilities than their counterparts in earlier generations, according to UCLA scientists. If their projections prove accurate, it could have a devastating impact on the nation’s health system.

To reach these conclusions, Teresa Seeman and colleagues queried data from the National Health and Nutrition Examination Surveys (NHANES) for the years 1988 and 1999.

They looked at 4 areas: activities of daily living, like walking from room to room; instrumental activities like doing chores; functional limitations like kneeling or stooping; and mobility, which includes walking one-quarter mile without a rest.

The study focused on adults born between 1930 and 1944, because this group could offer the most insight into the problems that will be associated with Baby Boomers who are now entering their 60s.

The researchers found that between 1988 and 1999, disability among people in their sixties rose 40-70% percent in each of the 4 areas except functional limitations, even after controlling for socioeconomic characteristics, health status and weight.

The increases were pronounced in non-white people, a subset of the US population that is growing most rapidly and that is known to have a higher incidence of obesity and lower socioeconomic status. These factors are associated with an increased risk of functional limitations and disabilities.

“If this is true, it’s something we need to address,” Teresa Seeman, the study’s principal investigator told BurrillReport. “If this trend continues unchecked, it will put increasing pressure on our society to take care of these disabled individuals.”

The study will appear in the January issue of the American Journal of Public Health.

Ever wonder why there isn’t a birth control pill for men?

Part of the reason is that the physiological mechanisms governing sperm production in men are less well understood than those governing ovulation in women.

Androgens are known to play a key role in normal sperm production and male fertility generally, but the mechanism by which androgens exert these effects had been largely unknown.

Now, a recent paper published in the FASEB Journal may have shed some light on the matter.

In the paper, Michelle Welsh and colleagues at the Centre for Reproductive Biology in Edinburgh studied androgen levels and sperm production in 2 groups of mice. The first group was normal, but the second had been engineered such that the peritubular myeloid cells in their testes lacked a particular gene that codes for an androgen hormone receptor.

In latter group, testis weight did not increase normally at puberty, and by the time they matured to adulthood they could produce only about 14% as many sperm cells as their normal counterparts. The findings were not explained by differences in testosterone, luteinizing hormone, or follicle-stimulating hormone levels.

The authors concluded that androgen action on the peritubular myeloid cells was therefore essential for normal testis function, spermatogenesis, and fertility in male mice, and seemed quite confident in their write-up that the findings would be easily reproduced in other mammals including humans.

“This study…could provide new insight for the development of new treatments for male infertility and perhaps new male contraceptives,” Welch told BurrillReport.
 
“Not only does this research pinpoint androgenic hormones and their cellular receptors as prime targets for the development of new birth control drugs, but it promises to speed the development of new agents to boost sperm production,” added Gerald Weissmann, who edits the FASEB Journal.