For years, people with a family history of Alzheimer's disease have shied away from genetic testing, which could reveal that they carry the ApoE4 protein - a genetic risk factor associated with a 10-fold higher chance of developing the incurable neurodegenerative condition.

However, new research has highlighted a potential pathway for early intervention methods that could help those at a high risk for Alzheimer's, making genetic screening for the disease as important as cholesterol tests are to preventing heart disease.

Researchers from The Buck Institute for Research on Aging, an independent research association based in Novato, Calif., have long been interested in discovering why ApoE4 is associated with such a high risk for Alzheimer's disease.

"Why is this the dominant risk factor?" study author Dr. Dale Bredesen, founding CEO of the Buck Institute, told FoxNews.com. "Though people have known this for 20 years, it's never been clear what it is that ApoE4 does to confer such risk."

Prior research had focused on the discovery that ApoE4 appears to affect the clearance of amyloid-beta (A-beta), a plaque that builds up in the brains of patients with Alzheimer's disease. However, Bredesen and his colleagues weren't convinced that this finding told the whole story of why ApoE4 causes Alzheimer's.

"Treating that hasn't worked very well," Bredesen said. "There's an emerging feeling, which we believe, that this is more than just about A-beta."

In a study published in The Proceedings of the National Academy of Sciences, Bredesen and his colleagues analyzed ApoE4 cell cultures and discovered that ApoE4 was also associated with a dramatic reduction in SirT1 - a protein associated with anti-inflammation, anti-aging and longevity.

Bredesen said that as SirT1 decreases, it affects a certain protein crucial to the storage or loss of memories - the amyloid precursor protein (APP).

"You have a molecule called the APP, present in neurons and most cells in your body, and at all times this APP is getting cleaved," Bredesen said. "It turns out there are two alternative patterns. So it is a little bit like how the government can go on shutdown or active. APP can go in the direction of memory or forgetting."

In Alzheimer's, Bredesen says people are on the 'wrong side' of this process - causing them to forget rather than retain memories.

However, by maintaining SirT1 levels, researchers believe they may be able to prevent these proteins from going awry. As a result of their discovery, Bredesen and his colleagues attempted to identify drugs that might be able to maintain levels of SirT1 in ApoE4 cell cultures. So far, they have successfully identified four drugs that seem to be effective - though they have yet to test their findings in humans.

"It gives us a leg up on saying, 'Okay, we can begin to look at how to treat people with ApoE4 even when they're young to make sure they never get Alzheimer's, by affecting that link between ApoE4and Alzheimer's,'" Bredesen said.

Furthermore, Bredesen and his colleagues also performed experiments in which they successfully reinserted SirT1 proteins back into cells already affected by ApoE4. By doing this, they were able to correct the abnormalities present in the cell and return it to a healthy state. This led Bredesen and his colleagues to speculate that treatment might be possible even for those already entering the early stages of Alzheimer's.

"Most people today don't want to know if they have ApoE4 because what can they do about it? This could change the landscape where we say everyone should know, just like with high cholesterol or high blood pressure, because you can do something about it," Bredesen said.

Regular exercise boosts teenagers` school grades -- and particularly helps girls in science, a British study said Tuesday.

The more physically active they were, the better children performed in school, according to findings published online in the British Journal of Sports Medicine.

And "girls` science results seemed to benefit the most", said a press statement.

Physical activity has long been suspected to boost brainpower, but little scientific evidence has existed until now.

For the study, researchers from England, Scotland and the United States measured the level of physical activity among nearly 5,000 11-year-olds who wore a motion-reading "accelerometer" for a week.

Their academic performance in English, maths and science was then assessed at the ages of 11, 13, and 16.

Children who had been more physically active at 11 performed better in all three phases and all three subjects.

Every 17 minutes of exercise per day at the age of 11 led to an additional improvement in marks for boys, and 12 minutes per day for girls by the age of 16, said the findings.

The effect was noticeably large for girls in science classes.

"This is an important finding, especially in light of the current UK and European Commission policy aimed at increasing the number of females in science subjects," wrote the authors.

Worryingly, the researchers observed that aged 11, boys averaged 29 minutes of moderate-to-vigorous exercise per day and girls about 18 -- far lower than the recommended 60 minutes.

"Their findings prompt the authors to speculate on what might happen to academic performance if children increased the amount of moderate-to-vigorous physical activity they did to the recommended 60 minutes," said the statement.

The children had been recruited from a large-scale ongoing project called the Avon Longitudinal Study of Parents and Children (ALSPAC) in southwest England.

The scientists adjusted the results for factors that could influence the findings, like a child`s birthweight, whether their mothers had smoked during pregnancy, weight and socioeconomic background.

Further research was needed to better understand how exercise results in improved marks, said the researchers.

"The findings have implications for public health and education policy by providing schools and parents with a potentially important stake in meaningful and sustained increases in physical activity," they wrote.

Decreased thyroid function, or hypothyroidism, is commonly associated with weight gain, but a new study has found that effective treatment with levothyroxine (LT4) to restore normal thyroid hormone levels is not associated with clinically significant weight loss in most people.

Researchers SY Lee, LE Braverman, and EN Pearce describe the retrospective review of patients with newly diagnosed primary hypothyroidism over an 8-year period, not caused by thyroid cancer or other forms of disease or associated with pregnancy or use of prescription weight loss medication.

It was found that about 52 percent of the patients lost weight up to 24 months after initiation of treatment with LT4.

Ronald J. Koenig , M.D., Ph.D, Professor, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, said because obesity and hypothyroidism are very common, there are many patients who have both conditions.

Koenig said that these patients and sometimes their physicians often assume the hypothyroidism is causing the obesity even though this may not be the case.

This study is important because it shows, unfortunately, that only about half of hypothyroid patients lose weight after the successful treatment of their hypothyroidism.

The study will be presented at the 83rd Annual Meeting of the American Thyroid Association, in San Juan, Puerto Rico.

When we sleep, our brains get rid of gunk that builds up while we're awake, suggests a study that may provide new clues to treat Alzheimer's disease and other disorders.

This cleaning was detected in the brains of sleeping mice, but scientists said there's reason to think it happens in people too.

If so, the finding may mean that for people with dementia and other mind disorders, "sleep would perhaps be even more important in slowing the progression of further damage," Dr. Clete Kushida, medical director of the Stanford Sleep Medicine Center, said in an email.

Kushida did not participate in the study, which appears in Friday's issue of the journal Science.

People who don't get enough shut-eye have trouble learning and making decisions, and are slower to react. But despite decades of research, scientists can't agree on the basic purpose of sleep. Reasons range from processing memory, saving energy to regulating the body.

The latest work, led by scientists at the University of Rochester Medical Center, adds fresh evidence to a long-standing view: When we close our eyes, our brains go on a cleaning spree.

The team previously found a plumbing network in mouse brains that flushes out cellular waste. For the new study, the scientists injected the brains of mice with beta-amyloid, a substance that builds up in Alzheimer's disease, and followed its movement. They determined that it was removed faster from the brains of sleeping mice than awake mice.

The team also noticed that brain cells tend to shrink during sleep, which widens the space between the cells. This allows waste to pass through that space more easily.

Though the work involved mouse brains, lead researcher Dr. Maiken Nedergaard said this plumbing system also exists in dogs and baboons, and it's logical to think that the human brain also clears away toxic substances. Nedergaard said the next step is to look for the process in human brains.

In an accompanying editorial, neuroscientist Suzana Herculano-Houzel of the Federal University of Rio de Janeiro said scientists have recently taken a heightened interest in the spaces between brain cells, where junk is flushed out.

It's becoming clearer that "sleep is likely to be a brain state in which several important housekeeping functions take place," she said in an email.

The study was funded by the National Institute of Neurological Disorders and Stroke. In a statement, program director Jim Koenig said the finding could lead to new approaches for treating a range of brain diseases.

A new blood test can help detect the presence of early-stage lung and prostate cancers - as well as any recurrences of these diseases.

In a new study presented at the Anesthesiology 2013 annual meeting, researchers have found that an increased level of serum-free fatty acids and their metabolites in the blood stream can help indicate the presence of lung cancer in the body.

According to the study's authors, such a test could be extremely beneficial for the detection and management of the disease.

"Lung cancer is the leading cause of cancer death in the U.S., and unlike some other cancers, there is no easy way to diagnose it," senior author Dr. David Sessler, professor and chair of the department of outcomes research at the Cleveland Clinic, told FoxNews.com. "The current standard is a spiral CT, which works well, but they are expensive, and they expose patients to radiation. So having a blood test for lung cancer would be very helpful."

Sessler said that he and his research team stumbled upon these biomarkers for lung cancer while conducting an entirely different experiment.

"It was complete serendipity," Sessler said. "We were looking for inflammatory markers associated with a particular type of anesthesia - general anesthesia versus epidural anesthesia. There was no difference in inflammation, but we noticed that patients with lung cancer had higher incidences of these fatty acids and their metabolites."

After making this discovery, the researchers decided to further analyze these potential biomarkers. They examined blood samples from 55 patients with lung cancer and 40 patients with prostate cancer, comparing them to samples from people without cancer. The blood samples from the cancer patients had one- to six-times greater amounts of the serum-free fatty acids and their metabolites than the samples from cancer-free patients.

In a second phase of the study, the researchers examined blood samples from 24 patients with lung cancer before they underwent curative surgery. They then analyzed the patients' blood at six and 24 hours after surgery. The level of serum-free fatty acids and their metabolites decreased three to 10 times within 24 hours after the cancerous tumors were removed.

The researchers didn't assess why the level of these compounds increased, but they said their findings are consistent with previous research on the relationship of serum-free fatty acids and cancer.

"The three fatty acids are necessary for cancer cell growth, and some cancers stimulate the release of these fatty acids," Sessler said.

Though the blood test was shown to be effective in detecting the disease, the researchers argue that it should not be used as the go-to test for lung cancer screenings. However, it could be helpful for a certain population of patients.

"It's by no means a perfect test; blood tests rarely are," Sessler said. "It is about 75 percent for sensitivity and specificity. It is probably not a good enough test to use for routine screening, but it well could be helpful for high risk patients or patients who have found a nodule but don't know if it's cancerous enough."

Sessler also said the blood test could be helpful for those who have already undergone lung cancer surgery to better understand if they will suffer recurrence.

"If someone who has lung cancer and has surgery, you might use this as a follow up," Sessler said. "Presumably the fatty acids go down after surgery, and an increase in concentration might tell you if patient is having a relapse."

While other blood tests do exist for some cancers - most notably the prostate-specific antigen (PSA) test for prostate cancer - Sessler said this is still an exciting discovery for the future of lung cancer treatment.

"Yes, there are some biomarkers for some cancers, but there's no general cancer biomarker, nor has there ever been an established biomarker for lung cancer," Sessler said.