Post-mortem studies of the brains of women with Alzheimer’s disease (AD) show a much lower estrogen content than similar women without the disorder, Reuters report.
The findings may help explain the higher prevalence of AD in women than men, since animal experiments show brain estrogen deficiency accelerates the brain “plaque“ build-up that characterizes the disease.
Blood estrogen analysis did not support the brain tissue findings, since serum estrogen was low in both the AD patients and normal subjects, Dr. Rena Li and colleagues at the University of Chicago noted.
Li said that “brain estrogen deficiency is more specific than blood estrogen deficiency“ in the development of AD.
“That is the key finding--the brain can’t manufacture estrogen.“
To examine the correlation between brain tissue findings and the onset and severity of AD, Li’s team conducted animal studies in which they crossed mice lacking an estrogen-synthesizing enzyme with mice carrying a protein related to AD plaque build-up.
The resulting animals had greatly reduced brain estrogen levels and early onset plaque formation. By contrast, mice that underwent ovary removal did not develop estrogen-deficient brain disease.
Li said the findings in these “ovariectomized“ mice support the fact that not all post-menopausal women develop AD. “It is brain-specific...and may have a genetic basis,“ she explained.
She said potential treatment of AD with estrogen therapy would require drug formulations that cross the tissue barrier that separates blood from the brain. Her team is currently screening a number of natural estrogen products to assess their ability to cross this barrier.

Certain fruit and vegetables were found to be particularly effective on cancer.

Certain fruit and vegetables were found to be particularly effective
Eating at least five portions a day of certain fruit and vegetables could cut the risk of developing pancreatic cancer by 50%, US researchers believe.
According to BBC News website, onions, garlic, beans, carrots, corn, dark leafy vegetables and citrus fruits were among the most protective foods.
A University of California team compared the diets of 2,200 people.
Cancer experts said previous studies had revealed similar findings, but more research was still needed.
More than 10,000 people die each year in the UK from pancreatic cancer. It remains largely untreatable, with the five-year survival rate at under 3%.
The report, published in the Cancer, Epidemiology, Biomarkers and Prevention journal, said eating five portions daily of the most protective vegetables cuts the risk in half.
Or it said eating any nine fruit or vegetables could have the same effect.
Raw vegetables were found to be more protective than cooked ones, the study said after conducting interviews with 532 people with the cancer, and 1,700 people who did not have the disease.
But researchers acknowledged the results may have been influenced by food which may often be eaten with the vegetables.
Report co-author Elizabeth Holly said, “Pancreatic cancer is not nearly as common as breast or lung cancer, but its diagnosis and treatment are particularly difficult.
“Finding strong confirmation that simple life choices can provide significant protection from pancreatic cancer may be one of the most practical ways to reduce the incidence of this dreadful disease.“
Dr. Julie Sharp, cancer information officer at Cancer Research UK, said, “Previous research has implied that a diet rich in fruit and vegetables may help to prevent pancreatic cancer.
“This research adds to these findings, but large-scale studies are vital to confirm whether fruit and vegetables really have an effect on pancreatic cancer risk.“
And she added other lifestyle factors, such as smoking, also played a key role.

Didgeridoo playing can help sleep according to researchers.
Swiss researchers from the Zurercher Hoehenklinik Wald hospital in Sweden found using the instrument for 25 minutes a day helped people with sleep apnoea, the British Medical Journal reported.
The disorder causes the throat to close and breathing to stop, waking the patient, but playing the instrument helped by strengthening the airways.
UK experts said such exercising of the airways was known to help.
About 5% of the population has the syndrome, which can cause people to wake up during the night.
Doctors normally advise sufferers to lose weight reports ananova.com.
The team identified 25 people with sleep apnoea and split them into two groups--one which was given lessons for four months, while the other was kept on a waiting list for lessons.
Patients who had lessons reported less sleepiness during the day and their partners said there were less disturbances.
Lead researcher Otto Braendli said larger trials were needed to confirm the findings.
He said, “Our results are the first to show that training the upper airways significantly improves sleep related outcomes.“

Miniaturized gyroscopes more commonly found in missile guidance systems can make sensitive biosensors for fast cancer diagnosis.
Micro-gyroscopes comprise a chip with a vibrating disc the size of a sand grain mounted at its centre, said the New Scientist.
The vibrations are highly sensitive to acceleration, so the chips can be used to detect motion in rockets, aircraft and anti-lock braking systems in cars.
But now Calum McNeil and his colleagues at the University of Newcastle in the UK have created a gyroscopic disc less than 0.1 millimeters across that can be used to “weigh“ proteins, which allows it to identify particular proteins produced by cancer cells. The disc targets the kind of protein that binds to a DNA coating on a cross on the disc’s surface.
The disc is electronically made to vibrate both up and down and side to side, like a ship rocking about on the sea. Initially it vibrates with the same frequency in both directions. But when a protein in a fluid sample binds to the DNA, it knocks it off balance, causing it to vibrate at a slightly different frequency in each direction.
By measuring this change, and knowing the particle must lie somewhere on the cross, the device can work out the mass of the protein, which will vary for different types of cancer and for proteins produced by healthy cells.
So it can accurately identify the captured particle and ignore normal proteins accidentally caught on the surface--a problem which has plagued other biosensors, says McNeil.
He stumbled on the idea for the detector while chatting to engineers designing micro-gyroscopes.
“They were frustrated because even a slight defect on the disc changes the frequency of vibration. I realized that we could use something that is a problem in engineering as a solution for medicine.“
McNeil believes that the detector will be much faster than conventional biosensors, such as the glucose detector used for people with diabetes. These rely on chains of chemical reactions to measure the target chemical, slowing down their result times.

Planting forests to soak up carbon dioxide from the atmosphere can have a range of side effects, including drying up streams and making soil saltier, according to a global study. The discovery highlights the tradeoffs involved in tree-planting projects, nature.com said.
Because plants use carbon dioxide to grow, planting forests of large, fast-growing trees is one way to remove the gas from the atmosphere, thus staving off global warming. But such forests need a lot of water, say Robert Jackson, of Duke University in Durham, North Carolina, and his colleagues.
The team surveyed more than 500 places where new forests have been planted over the past half-century. In 13% of cases, streams dried up completely for at least a year. On average, plantations cut local stream flow by more than 50%.
“It doesn’t matter where you are in the world, when you grow trees on croplands, you use more water,“ Jackson says. The effect can reduce the water available for drinking and irrigation, and harm local aquatic ecosystems.
And forest soils are saltier and more acidic, compared with other types of plant cover such as crops or grasslands, the researchers found. They publish their results in this week’s issue of Science1.
These changes occur partly because tree-planting projects choose fast-growing species that suck up more carbon dioxide, Jackson explains. Often these are evergreen trees that grow all year round, meaning that they take up a lot of carbon dioxide and water.
Some changes to water flow may be desirable, the team points out. For example, forest plantations in the US agricultural belt have reduced nutrient runoff from farmlands into the sea, which can cause algal blooms that kill marine life.
The key is to consider local factors when implementing afforestation projects, the researchers argue. “Policy-makers often have a set of ’carbon blinders’ on--they’re thinking and talking only about carbon,“ Jackson says.
Some nations and companies are currently planting forests as a way of earning ’carbon credits’ in international carbon markets. These allow greenhouse-gas emitters such as power companies to balance their emissions by buying carbon savings elsewhere.

The aggressive sexual activity of Asian elephants could be a key to understanding the human sixth sense, according to AFP.
The study, conducted by New Zealander Dave Greenwood and Elizabeth Rasmussen of the Oregon Heath and Sciences University, focused on the ways animals signal to each other.
Male Asian elephants are famed for their annual bouts of heightened sexual activity and aggression, called “musth“, during which they produce a notoriously pungent cocktail of chemicals to advertise their mating status, the researchers said Friday.
The jury is out on whether humans have the ability to communicate using pheromones but the research into elephants is considered a significant step forward in the understanding of this signaling in mammals.
The researchers found that more mature males impress females by including a balance of different versions of a particular pheromone called frontalin, which exists in two molecular “mirror-image“ forms.
“We found the frontalin is released by the elephants in specific ratios that depend on the animal’s age and stage of musth,“ Greenwood said.
Greenwood, honorary associate professor at Auckland University’s School of Biological Science, said the exact chemical blend of the pheromone emitted by older male elephants influenced both a female elephant’s interest in mating and how other surrounding elephants behave.
“We were certainly surprised by the results. This is the first example, in mammals, of the use of this very precise signaling and ratio of chemical compounds in signaling.
“All of the responses to the pheromone are such as trumpeting, running away, circling are translatable at the basic level to other animals including humans.“

Young adults with amblyopia, or lazy eye, can improve substantially and retain their gains under a new treatment developed by researchers at USC and three Chinese universities, according to Eurekalert.
A lazy eye in children appears normal but does not see properly, even with corrective lenses. If untreated, the eye will not develop fully, resulting in permanent loss of vision.
Amblyopia has been considered incurable in children older than eight. The new study, published online by Vision Research, documented a 70 percent improvement in eye chart performance in 19-year-old subjects. The average one-year retention rate was 90 percent.
The researchers trained the subjects in detection of a small “gabor“ (pronounced ga-BOR), a set of three contrasting dark and light ovals that neurophysiologists have identified as a basic unit of visual perception.
Surprisingly, improvement in this abstract exercise generalized to a marked improvement in standard vision tests. The seven subjects improved their overall visual acuity 25 to 216 percent, with an average of 70 percent.
Another 10 subjects in a slightly different training program showed an average improvement of 46 percent. Eight subjects in a control group showed no improvement.
“Detecting simple visual patterns turned out to be quite useful for improving visual acuity for amblyopia patients, typically measured by eye chart reading,“ said co-author Zhong-Lin Lu, professor of psychology in the USC College of Letters, Arts and Sciences and co-director of the Dornsife Neuroscience Imaging Center.
Normal subjects who received the same training did not show a general improvement in vision. A possible reason may be that a little stimulus goes a long way toward awakening the amblyopic eye, Lu said.
Next, the researchers plan to test their method on patients at a clinic in China. Other plans include developing a home training program.

American scientists used the self-assembling properties of DNA to mass-produce nanometer-scale structures on which patterns of molecules can be specified.
According to Science Daily, Duke University Researchers in Durham, N.C., said the achievement represents a step toward mass-producing electronic or optical circuits at a scale 10 times smaller than the smallest circuits now being manufactured.
Instead of using silicon as the platform for tiny circuits, as is done in the current manufacturing technique of photolithography, the Duke researchers used DNA strands to create grids less than one ten-millionth of a meter square.
The scientists were able to create the grids by using the binding properties of DNA to ensure that large numbers of DNA strands would assemble themselves in specified patterns.