Memory loss caused by brain damage is reversible

Degenerative brain diseases, including Alzheimers, could one day be treated with drugs that can reverse distressing loss of memory, according to a study released Sunday.

The very term "memory loss" could be a misnomer in such cases, suggests the study, published in British journal Nature: that cherished recollection of a first kiss, seemingly destroyed by disease, may have simply been rendered inaccessible by obstructed neural pathways.
In laboratory experiments, mice suffering the type of brain damage which in humans typically leads to dementia -- robbing victims of the ability to remember past events or even to recognize loved ones -- were able to recover memories acquired during earlier conditioning, according to the study carried out by researchers at the Massachusetts Institute of Technology.

Following a period of rehabilitation through mental stimulation, the genetically modified mice successfully performed tasks they had "forgotten" in the wake of damage inflicted on specific neural networks in the brain.

The same regenerative results were also later obtained through a drug treatment.

While there is no guarantee that the same techniques will work in humans, the study does raise "the possibility of recovering long-term memories in patients" ravaged by certain neurological disorders, according to lead author Li-Huei Tsai, who conducted the study with four colleagues.

Neurodegenerative diseases attack those parts of the brain and spinal cord that control bodily movement and process information stored in the form of memories.

When brain cells deteriorate or are destroyed, they are not replaced. Earlier studies have shown, however, that healthy neurons stimulated through mental activity or directly by chemicals can grow stronger and reconfigure themselves.

Tsai's breakthrough in a series of ingenious experiments was to demonstrate that this same process of remodeling can be reparative, unlocking memories rendered inaccessible by diseases causing "significant brain atrophy and neuronal loss."

The researchers began their experiment by selecting genetically modified mice in which a protein linked to neurodegenerative disease, called p25, could be switched "on" or "off" chemically.

Before this brain-damaging protein was activated, the mice demonstrated in two tests that they had learned how to avoid an electric shock, and how to navigate a maze quickly for a food reward.

After the animals were subjected to six-weeks of neurological degeneration, they could no longer perform these tasks. But an intensive, four-week regimen of "environmental enrichment" -- scientific jargon for access to lots of toys and play -- led to a sharp increase in learning ability and memory. Indeed, the mice passed the tests almost as well as control mice.

The researchers were careful to focus on long-term memories, thought to be stored in the cortical network, and not recently learned behavior, which is initially encoded in another part of the brain, the hippocampus.

Tsai and her colleagues had a hunch as to what was going on at a molecular level when the memories were retrieved and devised a further experiment to test it by chemically inhibiting an enzyme -- histone deacetylase (HDAC) -- known to interfere with gene transcription.

The results showed the same beneficial effect as the "environmental enhancement," suggesting that it could be the basis for a pharmaceutical treatment for memory loss.

"Using small molecules that target HDACs in patients with dementia could facilitate access to long-terms memories," the study concludes.

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Fat workers cost employers more

Overweight workers cost their bosses more in injury claims than their lean colleagues, suggests a study that found the heaviest employees had twice the rate of workers' compensation claims as their fit co-workers.

Obesity experts said they hope the study will convince employers to invest in programs to help fight obesity. One employment attorney warned companies that treating fat workers differently could lead to discrimination complaints.
Duke University researchers also found that the fattest workers had 13 times more lost workdays due to work-related injuries, and their medical claims for those injuries were seven times higher than their fit co-workers.

Overweight workers were more likely to have claims involving injuries to the back, wrist, arm, neck, shoulder, hip, knee and foot than other employees.

The findings were based on eight years of data from 11,728 people employed by Duke and its health system. Researchers found that workers with higher body mass indexes, or BMIs, had higher rates of workers' compensation claims.

The most obese workers — those with BMIs of 40 or higher — had the highest rates of claims and lost workdays. BMI is a measure of height and weight. A 6-foot, 300-pound person, for example, has a BMI of just over 40.

Study co-author Dr. Truls Ostbye said the findings should encourage employers to sponsor fitness programs.

"There are many promising programs," Ostbye said. "We'd like to see more research about what is truly effective."

James Hill, who heads the Center for Human Nutrition at the University of Colorado, said managers will pay attention to the findings because injuries mean more immediate financial losses than the future health-care costs of diabetes and heart disease.

"When you see that claims rates double, I think that's going to get people's attention," Hill said.

But there isn't enough good information about employer-sponsored programs that work, said John Cawley, an expert in the economics of obesity at Cornell University. Employers don't know whether paying for nutrition counseling, obesity surgery or anti-obesity drugs through health insurance makes economic sense, he said.

"It's now apparent to everybody that obesity is a big problem," Cawley said. "But the research isn't there to know where to get biggest bang for the buck."

Cawley noted that BMI does not distinguish muscle from fat and can equate a buff body builder to a couch potato. Although BMI, a measure of height and weight, is used in most obesity research, Cawley's research has found that blacks are particularly likely to be misclassified as obese by BMI.

New York employment attorney Richard Corenthal cautioned employers not to overreact with discriminatory policies.

"Employers need to be careful not to view this study as a green light to treat obese or overweight workers differently," Corenthal said.

The study, appearing in Monday's Archives of Internal Medicine, got funding from the National Institute for Occupational Safety and Health.

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Fat workers cost employers more

Overweight workers cost their bosses more in injury claims than their lean colleagues, suggests a study that found the heaviest employees had twice the rate of workers' compensation claims as their fit co-workers.

Obesity experts said they hope the study will convince employers to invest in programs to help fight obesity. One employment attorney warned companies that treating fat workers differently could lead to discrimination complaints.

Duke University researchers also found that the fattest workers had 13 times more lost workdays due to work-related injuries, and their medical claims for those injuries were seven times higher than their fit co-workers.
Overweight workers were more likely to have claims involving injuries to the back, wrist, arm, neck, shoulder, hip, knee and foot than other employees.

The findings were based on eight years of data from 11,728 people employed by Duke and its health system. Researchers found that workers with higher body mass indexes, or BMIs, had higher rates of workers' compensation claims.

The most obese workers — those with BMIs of 40 or higher — had the highest rates of claims and lost workdays. BMI is a measure of height and weight. A 6-foot, 300-pound person, for example, has a BMI of just over 40.

Study co-author Dr. Truls Ostbye said the findings should encourage employers to sponsor fitness programs.

"There are many promising programs," Ostbye said. "We'd like to see more research about what is truly effective."

James Hill, who heads the Center for Human Nutrition at the University of Colorado, said managers will pay attention to the findings because injuries mean more immediate financial losses than the future health-care costs of diabetes and heart disease.

"When you see that claims rates double, I think that's going to get people's attention," Hill said.

But there isn't enough good information about employer-sponsored programs that work, said John Cawley, an expert in the economics of obesity at Cornell University. Employers don't know whether paying for nutrition counseling, obesity surgery or anti-obesity drugs through health insurance makes economic sense, he said.

"It's now apparent to everybody that obesity is a big problem," Cawley said. "But the research isn't there to know where to get biggest bang for the buck."

Cawley noted that BMI does not distinguish muscle from fat and can equate a buff body builder to a couch potato. Although BMI, a measure of height and weight, is used in most obesity research, Cawley's research has found that blacks are particularly likely to be misclassified as obese by BMI.

New York employment attorney Richard Corenthal cautioned employers not to overreact with discriminatory policies.

"Employers need to be careful not to view this study as a green light to treat obese or overweight workers differently," Corenthal said.

The study, appearing in Monday's Archives of Internal Medicine, got funding from the National Institute for Occupational Safety and Health.

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Brain Structure Changes Before Memory Loss

Brain structure changes occur years before a person shows signs of memory loss caused by Alzheimer's disease or other forms of dementia, a new U.S. study suggests.

The study, published in the April 17 issue of the journal Neurology, included 136 healthy people over the age of 65 who underwent brain scans and cognitive tests at the start of the study and were all found to be cognitively normal. They were then assessed once a year for five years.

By the end of the five years, 23 participants had developed mild cognitive impairment (MCI), and nine of those 23 people were later diagnosed with Alzheimer's disease.
The brain scans revealed that the 23 who developed MCI or Alzheimer's had less gray matter in key memory processing areas of their brains at the beginning of the study. Those 23 people also scored lower on cognitive tests at the start of the study, although their scores were within the normal range.

"We found that changes in brain structure are present in clinically normal people an average of four years before MCI diagnosis," study author Dr. Charles D. Smith, of the University of Kentucky Medical Center in Lexington, said in a prepared statement.

"We knew that people with MCI or Alzheimer's disease had less brain volume, but before now, we didn't know if these brain structure changes existed, and to what degree, before memory loss begins," he said.

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Strongest genetic marker for obesity identified

British gene hunters said Thursday they have found the strongest DNA marker yet for obesity, and one that is very common among most Europeans.

The investigators first identified the gene, FTO, in the DNA of people with type 2, or late-onset diabetes, a condition that is lifestyle-related.

They were surprised to find the marker was associated with increased body fat rather than insulin production, so they scoured other DNA databases to see if the gene predisposed a person to obesity.
The results of that inquiry, the largest such undertaking of its kind to date, revealed that a variant of FTO was closely correlated with obesity, which has emerged as a major public health challenge in many developed nations.

The study showed that half of white Europeans carry one or more variants in their DNA, the researchers said.

Individuals with one copy of the FTO variant had a 30 percent higher risk of being obese than people without it.

In people with two copies of the "fat" gene, the risk rose to 67 percent, and they packed an additional three kilograms (6.6 pounds) in fat on average compared to people without any copies of the allele.

"Our findings suggest a possible answer to someone who might ask 'I eat the same and do as much exercise as my friend next door, so why am I fatter?' There is clearly a component to obesity that is genetic," said professor Andrew Hattersley, of the Peninsula Medical School, Exeter, and study co-author.

It's not clear why the gene predisposes people for increased body fat and higher rates of obesity, but it opens new avenues of investigation for researchers looking into obesity and related problems such as heart disease and diabetes, the researchers said.

"Even though we have yet to fully understand the role played by the FTO gene in obesity, our findings are a source of great excitement," said professor Mark McCarthy of Oxford University. "New scientific insights will hopefully pave the way for us to explore novel ways of treating this condition."

The researchers have only looked at one ethnic group so far -- white Europeans from Britain, Finland, Italy and northern Europe -- but they are confident that the findings will hold up in other populations given the scope of the study.

Investigators examined the DNA of 39,000 people, more than 10 times the number used in a comparable earlier study.

The hope is to examine the DNA of African Americans and South Asians next, the investigators told journalists in a conference call. Problems with obesity and excess weight have been documented in both populations.

The study was a collaborative effort involving 24 geneticists in Britain. The project was funded by the Wellcome Trust, the Britain's largest medical research charity.

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Multivitamins lower risk of underweight newborns

Women who take multivitamin supplements during pregnancy have significantly lower risk of giving birth to an underweight infant, according to a study in the Thursday edition of the New England Journal of Medicine.

Tests carried out in Tanzania on 8,468 pregnant women who were not infected with the
AIDS virus "demonstrated that multivitamin supplements significantly reduced the risks of low birth weight and a birth size that was small-for-gestational age, by 18 percent and 23 percent, respectively," the researchers said in a statement published Wednesday.

Test participants enrolled at 12 to 27 weeks gestation. Half of the group took multivitamins -- vitamins C, E and a variety of vitamins B -- every day while the other half took a placebo until six weeks after delivery.

Vitamin A and zinc were not added into the vitamin cocktail because previous studies failed to show a beneficial effect of those nutrients.

Women from both groups also received iron and folate supplementation and malaria prophylaxis, which is standard prenatal care in Tanzania.

Birth weight is influenced by factors that include maternal health, nutritional status and micronutrient deficiencies, according to the study's authors.

"Each year an estimated 20 million children are born with low birth weight worldwide, more than 95 percent of them in developing countries," the statement read.

Low birth weight -- 2,500 grams (5.5 pounds) or less -- "is associated with increased risk of negative health outcomes, including neonatal and infant mortality, poor growth and cognitive development, and morbidity due to chronic diseases later in life, such as diabetes and heart disease."

The study, the largest to date on the subject, was conducted by researchers from the Harvard School of Public Health (HSPH) and Muhimbili University College of Health Sciences in Dar es Salaam.

Wafaie Fawzi, professor of nutrition and epidemiology at HSPH and the study's main investigator, said his team recommends "that multivitamins be considered for all pregnant women in developing countries, regardless of their
HIV status."

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Vitamin pills prevent low-weight babies

Extra vitamin supplements can reduce the risk of having an underweight or undersized baby, and all pregnant women in developing countries should get them, researchers said on Wednesday.

But the team, reporting in the
New England Journal of Medicine, said the supplements did not lower the likelihood of premature birth or losing the fetus before birth.

The study, conducted in Dar es Salaam, Tanzania, involved 8,468 pregnant women who were free of the
AIDS virus and who received iron and folic acid supplements, both proven prenatal treatments. Half were given supplements containing vitamins C, E and a mix of B vitamins. The rest got placebos.

The fetal death rate stayed around 5 percent and the rate of premature delivery was nearly 17 percent regardless of whether mothers got the vitamins, the team, led by Wafaie Fawzi of Harvard University's School of Public Health, reported.

But the risk of having a low birth-weight baby dropped from 9.4 percent among the placebo recipients to 7.8 percent for the babies whose mothers took the supplements.

"In light of these findings, we recommend that multivitamins be considered for all pregnant women in developing countries, regardless of their
HIV status," Fawzi said in a statement.

His team previously found supplements saved the lives of babies of HIV-infected women.

About 20 million low birth-weight babies are born each year, 96 percent of them in developing countries. Babies of low birth weight, defined as less than 5.5 pounds (2,500 grams), are more likely to die young, have growth and learning difficulties and may later be prone to diabetes and heart disease.

"Many developing countries have a system for providing prenatal iron and folate supplements; the supplements are produced in bulk by the
United Nations Children's Fund at an estimated cost of less than $1 per person for the duration of the pregnancy," the researchers wrote.

Adding the extra vitamins, they said, would probably increase that cost by just 20 cents, "and scaling up prenatal multiple micronutrient supplementation could be a highly cost-effective approach to improving both outcomes among pregnant women in developing countries."

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Pneumococcal vaccine beyond expectations

A vaccine to fight common bacterial diseases has produced significant and unexpected drops in repeat ear infections and the need for inserted ear tubes in children since its U.S. introduction in 2000, researchers reported on Monday.

"This is exciting news for parents whose children suffer from frequent and painful ear infections," said Katherine Poehling, a pediatrician at Wake Forest University Baptist Medical Center and lead author of the study.

The vaccine "is going beyond what it was supposed to do," she said in an interview.

The vaccination, given initially at 2, 4 and 6 months of age, was designed to combat a number of pneumococcal infections, including ear infections that most children have at least once by the time they turn 2 years old.

But Poehling said the new research shows that the vaccine was also preventing repeat infections, which occur three or four times a year in up to nearly a third of all children, often requiring the insertion of ear tubes to equalize pressure.

The vaccine has also helped adults, she said, by preventing the general spread of disease.

"We have seen declines in the incidence of serious infections such as pneumococcal meningitis in both children and adults, as well as the number of children developing frequent ear infections," she said.

The study, published in the April issue of "Pediatrics," the journal of the American Academy of Pediatrics, looked at data from more than 150,000 children in Tennessee and another 26,409 in upstate New York enrolled in health insurance programs from birth to age 5.

Since the introduction of Pneumococcal Conjugate Vaccine, it found, the proportion of children who developed frequent ear infections and the proportion who received ear tubes declined by 16 percent in Tennessee and 25 percent in New York by age 2.

The vaccine, called PCV7, is marketed by Wyeth under the brand name Prevenar.

Poehling called the results "very exciting" but said public health officials need to keep watch of the situation to make sure pneumococcal strains not included in the vaccine do not become a problem.

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Stress in Chinese cities ruining sex lives

Stress in China's cities is taking a toll on residents' sex lives, with 30 percent of middle-aged couples having no intimate relations, according to a survey published in the state-run press on Monday.

The survey of nearly 33,000 people in 10 Chinese cities found that relentless pressure from families and jobs was having a major impact on the sex lives of both new couples and those who have been married for a long time.

Thirty percent of middle-aged couples have given up on sex altogether as a result of physical or psychological problems related to stress, according to the results of the survey published in the China Daily newspaper.

One quarter of couples aged under 30 reported similar problems.

The survey, conducted by a US pharmaceutical firm and the Beijing-based China Population Communication Centre, also found 45 percent of men in relationships suffered from erectile dysfunction.

"Due to the heavy burden having a family and a career puts on middle-aged people today, sexual dysfunction is affecting more and more men, overshadowing their relationship with their wives," the paper quoted Qiu Xiaolan from the China Sexology Association as saying.

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