AstraZeneca hunts stem cell cure for eye disorder

LONDON

AstraZeneca took its first significant step into regenerative medicine using stem cells today by signing a deal with University College London to develop ways to repair eyesight in people with diabetes.

Previously, AstraZeneca's interest in stem cells had been primarily in using them as a drug discovery tool.

The three-year research collaboration will see scientists from the drugmaker and the university teaming up to seek new treatments for diabetic retinopathy.

Most patients with type 1 diabetes will develop retinopathy and about 20 to 30 per cent will become blind. A large number of patients with type 2, or adult-onset, diabetes also develop

retinopathy as their underlying disease progresses.

The research work is early stage and will not result in a medicine getting to market for many years but the collaboration is a sign of big drugmakers' growing interest in the therapeutic

potential of stem cells.

The deal also emphasises AstraZeneca's increasing focus on diabetes as a disease area. The Anglo-Swedish company has a recently launched diabetes drug called Onglyza, which was

developed with Bristol-Myers Squibb, and the two partners are also working on a second one called dapagliflozin.

Sep 2010

Artificial "skin" materials can sense pressure

CHICAGO

New artificial ''skin'' fashioned out of flexible semiconductor materials can sense touch, making it possible to create robots with a grip delicate enough to hold an egg, yet strong enough to grasp the frying pan, US researchers said.

Scientists have long struggled with a way to make robotic devices capable of adjusting the amount of force needed to hold and use different objects. The pressure-sensitive materials are

designed to overcome that challenge.

''Humans generally know how to hold a fragile egg without breaking it,'' said Ali Javey, an electrical engineer at the University of California Berkeley, who led one of two teams

reporting on artificial skin discoveries in the journal Nature Materials yesterday.

''If we ever wanted a robot that could unload the dishes, for instance, we'd want to make sure it doesn't break the wine glasses in the process. But we'd also want the robot to be able

to grip a stock pot without dropping it,'' Javey said in a statement.

Javey's team found a way to make ultra tiny ''nanowires'' from an alloy of silicon and germanium. Wires of this material were formed on the outside of a cylindrical drum, which was

then rolled onto a sticky film, depositing the wires in a uniform pattern.

Sheets of this semiconductor film were then coated with a layer of pressure-sensitive rubber. Tests of the material showed it was able to detect a range of force, from typing on a

keyboard to holding an object.

A second team led by Zhenan Bao, a chemical engineer at Stanford University in California, used a different approach, making a material so sensitive it can detect the weight of a

butterfly resting on it.

Bao's sensors were made by sandwiching a precisely molded, highly elastic rubber layer between two electrodes in a regular grid of tiny pyramids.

''We molded it into some kind of microstructure to incorporate some air pockets,'' Bao said in a telephone interview. ''If we introduce air pockets, then these rubber pieces can bounce back.''

When this material is stretched, the artificial skin measures the change in electrical activity. ''The change in the thickness of the material is converted into an electrical signal,'' she said.

Eventually, the teams hope artificial skin could be used to restore the sense of touch in people with prosthetic limbs, but scientists will first need a better understanding of how to

integrate the system's sensors with the human nervous system.

Javey's artificial skin is the latest application of new ways of processing brittle, inorganic semiconductor materials such as silicon, into flexible electronics and sensors.

Earlier this year, a team at the California Institute of Technology in Pasadena devised a way to make flexible solar cells with silicon wires that are thin enough to be used in clothing.

Sep 2010

Cilostazol may prevent secondary stroke in Asians

HONG KONG

The anti-clotting drug cilostazol may work better than aspirin in preventing secondary stroke in east Asian patients, a study in Japan has found.

In a paper published on Saturday in The Lancet Neurology, the researchers said cilostazol reduced by 26 per cent the risk of recurrent stroke compared with aspirin.

''Cilostazol ... might be superior to aspirin for prevention of stroke after an ischaemic stroke, and was associated with fewer haemorrhagic events,'' wrote the researchers, led by

Yukito Shinohara at Tachikawa Hospital in Tokyo.

The study was funded by Otsuka Pharmaceutical Co, which manufactures cilostazol under the brand name Pletal. The company is a unit of Japan's Otsuka Holdings Co Ltd, a maker of

drugs and food products.

The study involved 2,757 stroke patients, with half of them given 100 mg of cilostazol twice daily and the other half 81 mg of aspirin once daily for between one to five years.

The participants were monitored for an average of 29 months and fewer patients suffered a second stroke in the cilostazol group (82) than in the aspirin group (119).

Twenty-three patients who took cilostazol suffered haemorrhage compared to 57 who were given aspirin.

''Cilostazol reduced the risk of major bleeding by 54 percent,'' the researchers wrote.

However, more of those who took cilostazol complained about side effects such as headache, diarrhoea, palpitations and dizziness.

Sep 2010

B vitamins found to halve brain shrinkage in old

LONDON

Daily tablets of large doses of B vitamins can halve the rate of brain shrinkage in elderly people

with memory problems and may slow their progression towards dementia, data from a British trial showed.

Scientists from Oxford University said their two-year clinical trial was the largest to date into the effect of B vitamins on so-called ''mild cognitive impairment'' -- a major

risk factor for Alzheimer's disease and other forms of dementia.

Experts commenting on the findings said they were important and called for larger, longer full-scale clinical trials to see if the safety and effectiveness of B vitamins in the prevention

of neurodegenerative conditions could be confirmed.

''This is a very dramatic and striking result. It's much more than we could have predicted,'' said David Smith of Oxford's department of pharmacology, who co-led the trial.

''It is our hope that this simple and safe treatment will delay development of Alzheimer's in many people who suffer from mild memory problems.''

Mild cognitive impairment (MCI) affects around 16 percent of people aged over 70 worldwide and is characterised by slight problems with memory loss, language or other mental functions.

MCI does not usually interfere with daily life, but around 50 percent of people diagnosed with it go on to develop the far more severe Alzheimer's disease within five years. Alzheimer's

is a mind-wasting disease for which there are few treatments and no cure, and which affects 26 million people around the world.

Smith and colleagues conducted a two-year trial with 168 volunteers with MCI who were given either a vitamin pill containing very high doses of folic acid, vitamin B6 and vitamin

B12, or a placebo dummy pill.

These B vitamins are known to control levels of an amino acid called homocysteine in the blood, and high blood levels of homocysteine are linked to an increased risk of developing

Alzheimer's disease.

Helga Refsum, who also worked on the trial, stressed that vitamins were given in extremely high doses.

''This is a drug, not a vitamin intervention,'' she said. The pills, called ''TrioBe Plus'' contained around 300 times the recommended daily intake of B12, four times daily advised

folate levels and 15 times the recommended amount of B6.

Brain scans were taken at the beginning and the end of the trial to monitor the rate of brain shrinkage, or atrophy.

The results, published in the Public Library of Science (PLoS) One journal, showed that on average the brains of those taking the vitamin treatment shrank at a rate of 0.76 percent a

year, while those taking the dummy pill had an average brain shrinkage of 1.08 percent.

People who had the highest levels of homocysteine at the start of the trial benefited the most from the treatment, with their brains shrinking at half the rate of those on the placebo.

Although the trial was not designed to measure cognitive ability, the researchers found those people who had lowest rates of shrinkage had the highest scores in mental tests.

Commenting on the study, Paul Matthews, a professor of clinical neurology at Imperial College London said that although the vitamins used are generally safe and inexpensive, the study

''should not drive an immediate change in clinical practice''

''Instead, it sets out important questions for further study and gives new confidence that effective treatments modifying the course of some dementias may be in sight,'' he said.

Sep 2010

Two gene mutations mark deadly ovarian cancer

WASHINGTON

Researchers have identified two new genetic mutations that cause a significant number of

the hardest-to-treat kinds of ovarian cancer, and say they point to a new ''on-off'' switch for tumors.

They hope their findings may eventually help doctors better tailor cancer treatments and also lead to the development of drugs to treat these forms of cancer.

The findings, published by two separate teams of researchers in the journal Science and the New England Journal of Medicine, also suggest a previously unknown mechanism for

how cancer begins.

The genes affect ovarian clear cell carcinoma, one of the most aggressive forms of ovarian cancer. It accounts for about 10 percent to 12 percent of ovarian cancer, itself one of the

deadliest and most difficult to treat tumor types.

Clear cell carcinoma usually is not affected by chemotherapy. It is sometimes linked to an overgrowth of uterine tissue called endometriosis.

Writing in Science, Dr. Bert Vogelstein and colleagues at Johns Hopkins University in Baltimore named the two new genes as ARID1A and PPP2R1A.

''They may provide opportunities for developing new biomarkers and therapies that target those genes,'' Nickolas Papadopoulos of Johns Hopkins, who worked on the study, said in

a statement.

Vogelstein, Papadopoulos and other members of the team own stock in Inostics, a company based in Hamburg, Germany that is developing tests to help diagnose cancer.

Dr. David Huntsman of the British Columbia Cancer Agency published a separate study in the New England Journal of Medicine focusing on ARID1A. They found it was mutated not only

in ovarian clear-cell carcinoma but also in a second type of ovarian tumor linked with endometriosis.

''Overall, 46 percent of patients with ovarian clear-cell carcinoma and 30 percent of those with endometrioid carcinoma had ... mutations in ARID1A,'' they wrote. They did not find the

mutation in other ovarian tumor types.

The ARID1A gene is also a suspect in some cases of lung and breast cancer, Huntsman's team said.

It is involved in a process called chromatin remodeling, which helps squeeze DNA into cells and control when and how it gets ''read'' to perform a biological function.

The mutation in ARID1A allows DNA to be improperly ''read'' and turned on, the Johns Hopkins team said.

''Taken together, these data suggest that ARID1A is a classic tumor-suppressor gene,'' Huntsman's team wrote. These genes, when not mutated, help stop tumors -- BRCA1 and p53 are two other well-known examples.

About 10 to 20 percent of breast and ovarian cancers are due to BRCA1 or BRCA2 genes.

An estimated 230,000 women worldwide are diagnosed with ovarian cancer each year. Most are not diagnosed before the cancer has spread, because it causes only vague symptoms, and

nearly 70 percent of those with advanced disease die within five years.

Sep 2010

Long-term weight loss may be harmful to health

HONG KONG

Long-term weight loss may release into the blood industrial pollutants linked to illnesses like diabetes, hypertension and rheumatoid arthritis, researchers said today.

These compounds are normally stored in fatty tissues, but when fat breaks down during weight loss, they get into the blood stream, said lead researcher Duk-Hee Lee at the Kyungpook

National University in Daegu in South Korea.

''We are living under the strong dogma that weight loss is always beneficial, but weight gain is always harmful...but we think that increased (pollutant) levels (in the blood) due to

weight loss can affect human health in a variety of ways.

Lee and an international team of colleagues studied 1,099 participants in the United States and concentrations of seven such compounds in their blood, they said in a paper published

in the International Journal of Obesity.

''Once released into the bloodstream, these pollutants are able to reach vital organs,'' the researchers said in a statement.

Those who lost most weight over 10 years had the highest concentrations of the compounds, called persistent organic pollutants (POPs), compared to those who gained or maintained a

steady weight.

''There is emerging evidence that POPs ... are not safe. POPs (are) linked to type 2 diabetes, hypertension, coronary heart disease, rheumatoid arthritis, periodontal disease,'' Lee

said.

The researchers factored in age, gender and race to explain the differences in concentrations of these pollutants but weight history remained a statistically significant factor.

More studies were needed to establish if such harm outweighed the benefits to be gained from weight loss, Lee said.

Sep 2010

MEMORIES-MEN

NEW YORK

Lost the car keys? Forgot someone's name? Many elderly people suffer slight cognitive problems but men are more likely than women to suffer momentary memory lapse or

senior moments, according to a US study.

Researchers from the Mayo Alzheimer's Disease Research Center in Rochester, Minnesota, found 19 per cent of men aged 70 to 89 years had so-called mild cognitive impairment, compared

to only 14 percent of women.

People with mild cognitive impairment have problems with memory but can carry out everyday activities and generally realize that they're forgetful. The National Institutes of

Health says ''mild cognitive impairment'' falls in between normal forgetfulness and dementia.

Researcher Dr Ronald Petersn said the findings were surprising because Alzheimer's disease, which is preceded by this type of mental decline, affects more women than men.

Even after accounting for differences in education, age, and diseases like diabetes and hypertension, men had about 50 percent higher odds than women of having mild cognitive

impairment.

Sep 2010