Researchers in the United States say they have developed a prototype blood test that can tell with 90 percent accuracy whether a healthy person will develop Alzheimer`s disease within three years.

The test looks for 10 signatures of fatty proteins called lipids, according to a study published on Sunday in the journal Nature Medicine.

It could help families of people developing the cognitive disorder make early decisions on how best to care for them and may also aid the search for treatment, the authors said.

Several years of clinical trials are likely to be needed to assess the prototype technique, the first blood "biomarker" to predict the tragic degenerative disease.

Alzheimer`s, caused by toxic proteins that destroy brain cells, is a currently incurable and fatal degenerative disease.

Around 35 million people have the disease, a tally that is expected to reach 115 million people by 2050, according to the World Health Organization.

"Our novel blood test offers the potential to identify people at risk for progressive cognitive decline and can change how patients, their families and treating physicians plan for and manage the disorder," said Howard Federoff, a professor of neurology at Georgetown University Medical Center in Washington.

It could also help efforts to treat the disease, he said in a press release.

Attempts to develop drugs for Alzheimer`s have failed possibly because they are tested when the disease has progressed too far, Federoff said.

These treatments may have a better chance of braking or reversing the disease if they are trialled at a much earlier stage, he said.

The researchers started by taking blood samples from 525 healthy volunteers aged 70 and older.

Three years later, they looked at a group of 53 volunteers who had developed symptoms of early Alzheimer`s or a memory-affecting condition known as amnestic mild cognitive impairment (aMCI).

The blood samples from this group were compared against the samples from 53 otherwise healthy volunteers to see what the difference was.

From this, the scientists spotted the 10 telltale lipid proteins, which appear to be metabolised residues of brain cell membranes.

A new study has revealed that Restless Legs Syndrome (RLS) may be a possible biomarker for other underlying disease.

The study done by a nationally-recognized sleep expert found that patients with RLS have a higher mortality rate and are prone to cardiovascular diseases and hypertension.

Boston Medical Center neurologist Sanford H. Auerbach said that men with RLS were more likely to be diagnosed with lung disease, endocrine disease, diseases of nutrition and metabolism and immune system problems.

The study was published in Neurology the medical journal of the American Academy of Neurology.

Clinical trials are to begin soon on a new vaginal ring that promises to provide months of protection against pregnancy, HIV and herpes, US researchers said Wednesday.

The device, which is similar to birth control rings already on the market, delivers both an antiretroviral drug and a contraceptive which are slowly released over 90 days.

A report on the ring and how it was developed by scientists at Northwestern University is published in the peer-reviewed journal PLOS ONE.

The ring could offer women an alternative that eliminates the anxiety of missed pills and requires a lower dose of an antiretroviral drug aimed at preventing HIV since it is delivered at the point of transmission.

Scientists and AIDS prevention advocates have been trying to develop a ring like this for a long time, said Rowena Johnston, vice president and director of research at amfAR, the Foundation for AIDS Research.

"If you have something that is long acting that people don`t have to think about every time they have sex but something that is in place, that is thought to be a boon," she said.

While the ring is only designed to protect against transmission during vaginal sex, it could be a valuable tool for some women, she said.

"And it is probably not easily detected by the male partner, if that is important to you," Johnston added.

Both drugs released by the ring -- levonorgestrel and tenofovir -- are already used to prevent pregnancy and the spread of HIV.

Tenofovir -- which inhibits HIV and herpes replication in susceptible cells -- is taken orally by 3.5 million HIV-infected people worldwide.

It has been found to help prevent HIV infection as well, but so far only with pills that must be taken daily.

A gel which delivers tenofovir has been found to be somewhat effective in clinical trials but the gel needs to be inserted into the vagina before and after sex.

Many of the women in the clinical trials did not use the gel every time they had sex.

"Products only work when they are used," said study co-author David Friend, product development director at CONRAD, which develops reproductive health technologies for low-income countries and is affiliated with Eastern Virginia Medical School.

"By having a ring that can remain in the body for up to 90 days, our hope is that this ring will offer a solution to increase adherence, and therefore provide greater protection against HIV while also preventing pregnancy," Friend said.

The differences between the two drugs presented a "huge" design challenge, said Northwestern University biomedical engineer Patrick Kiser, who holds the ring`s patent.

Tenofovir dissolves easily whereas the contraceptive drug levonorgestrel is highly insoluble. The drugs also had to be delivered in drastically different -- but consistent -- doses.

"A lot of engineering has gone into developing the ring," Kiser said.

The ring uses a new kind of polymer -- or chain of molecules -- that swells in the presence of bodily fluids and is capable of delivering up to 100 times more tenofovir than current intravaginal rings.

Researchers including and an Indian origin researcher has said that male hormones, also called androgens, help drive the development of follicles - structures that contain and ultimately release an egg that can be fertilized by a man's sperm.

The research also details how male hormones boost the production of follicles in mice. Authors believe the study provides potential biological targets to enhance fertility in women with diminished ovarian reserve, who produce few or no follicles in response to IVF drugs designed to boost follicle development.

Using multiple animal models and cell experiments, Stephen R. Hammes, M.D., Ph.D.,senior study author and professor of Endocrinology at the University of Rochester School of Medicine and Dentistry, and lead study author Aritro Sen , Ph.D., research assistant professor of Endocrinology at the medical school found that male hormones promote follicle development in two ways.

First, they prevent follicles from dying at an early stage. They do this by ramping up a molecule that stops cells from self destructing, a process called apoptosis. Hammes and Sen speculate that if a woman doesn't have enough androgens (male hormones), more of her follicles may be dying and fewer progressing to a mature stage when they produce and release an egg.

Second, androgens make ovarian cells more sensitive to follicle-stimulating hormone or FSH, which promotes follicle growth. They do this by creating more FSH receptors - molecules on the surface of ovarian cells that jumpstart the follicle making process in response to the hormone.

When the team administered small doses of androgens to mice that were taking the equivalent of medications given to women undergoing IVF therapy, they developed more mature, egg-containing follicles than mice that didn't receive androgens.

The androgen-treated female mice also released larger numbers of eggs with ovulation.

The study has been published in the Proceedings of the National Academy of Sciences.

A research team has found how the immune system makes a powerful antibody that blocks HIV infection of cells by targeting a site on the virus called V1V2.

Analyses of the results of a clinical trial of the only experimental HIV vaccine to date to have modest success in people suggest that antibodies to sites within V1V2 were protective.

The new findings point the way toward a potentially more effective vaccine that would generate V1V2-directed HIV neutralizing antibodies.

The study led by scientists from the National Institute of Allergy and Infectious Diseases (NIAID) began by identifying an HIV-infected volunteer in the CAPRISA cohort who naturally developed V1V2-directed HIV neutralizing antibodies, named CAP256-VRC26, after several months of infection.

Using techniques similar to those employed in an earlier study of HIV-antibody co-evolution, the researchers analyzed blood samples donated by the volunteer between 15 weeks and 4 years after becoming infected.

This enabled the scientists to determine the genetic make-up of the original form of the antibody; to identify and define the structures of a number of the intermediate forms taken as the antibody mutated toward its fullest breadth and potency; and to describe the interplay between virus and antibody that fostered the maturation of CAP256-VRC26 to its final, most powerful HIV-fighting form.

Notably, the study revealed that after relatively few mutations, even the early intermediates of CAP256-VRC26 can neutralize a significant proportion of known HIV strains.

This improves the chances that a V1V2-directed HIV vaccine developed based on the new findings would be effective, according to the scientists, who have begun work on a set of vaccine components designed to elicit V1V2 neutralizing antibodies and guide their maturation.