By Jane Dreaper Health correspondent, BBC News

Alzheimer's disease drugs raise levels of the neurotransmitter acetyl choline

Thousands of patients with advanced Alzheimer's disease could benefit from drugs, research suggests.

A study in the the New England Journal of Medicine found that patients who stayed on the dementia drug Aricept had a slower decline in their memory.

The drug tends not to be prescribed once sufferers progress beyond moderate symptoms.

Medicines regulator NICE said its guidelines supported continuing treatment where there were benefits.

The patent for the medicine Aricept, which is used to treat Alzheimer's disease, expired recently. Much cheaper versions under the generic name donepezil are already available for about £12 a month.

The researchers say their new evidence could lead to twice as many Alzheimer's sufferers worldwide being given medication.

The trial involved 295 Alzheimer's patients in England and Scotland who had been taking Aricept.

One set were given placebo tablets while another set stayed on Aricept. A third set were given another drug, Ebixa, or memantine, which is usually prescribed only in the later stages of Alzheimer's.

The fourth batch of patients received a combination of both drugs.

The researchers assessed each group for a year, looking at their cognitive scores on factors like memory, and also at how well they coped with everyday tasks such as dressing and eating.

The drugs were unable to halt the decline of patients, but they slowed it down.

The study's lead author, Professor Robert Howard from King's College London Institute of Psychiatry, said: "For the first time, we have robust and compelling evidence that treatment with these drugs can continue to help patients at the more severe stages.

"Patients who continued taking donepezil were about four months ahead in how they were able to remember, communicate and perform daily tasks than those who stopped taking the drugs.

"It means a lot to doctors and carers to see differences like that. These improvements were sustained throughout the year.

"It's fair to say that both drugs have independent, positive effects at this stage of dementia. I'm advising hospital colleagues to continue patients on donepezil, when it's tolerated, and to add in memantine."

About 500,000 people in the UK are thought to have Alzheimer's disease - with only about 10% who are in the earlier stages currently on drug treatment.

NHS funding of dementia drugs has been controversial in the past. The National Institute for Health and Clinical Excellence (NICE) set restrictions in 2006, which campaigners tried to overturn in court.

A year ago, revised NICE guidelines accepted that medicines including Aricept were cost-effective and could be prescribed earlier in the course of the disease.

Professor Clive Ballard from the Alzheimer's Society, which part-funded the trial alongside the Medical Research Council, said: "Usual practice has been to discontinue the treatment once patients have declined to a certain stage.

"This trial suggests the default position should be the other way round, because most people are benefiting.

"It's not so much the NICE guidance that needs to change - but how clinicians interpret it."

NICE said its guidelines did not include any specific recommendations on when to discontinue medicines.

Dr Simon Ridley from Alzheimer's Research UK said: "Trials such as this are extremely important for informing decisions about the way medication is prescribed.

"It would be helpful to see longer-term trials to determine exactly how long the benefits seen in this study might last.

"Sadly we still lack a treatment that can stop Alzheimer's disease in its tracks."

Around 1,200 people have died of Ebola virus infection since 1976

Scientists have developed a vaccine that protects mice against a deadly form of the Ebola virus.

First identified in 1976, Ebola kills more than 90% of the people it infects.

The researchers say that this is the first Ebola vaccine to remain viable long-term and can therefore be successfully stockpiled.

The results are reported in the journal Proceedings of National Academy of Sciences.

Ebola is transmitted via bodily fluids, and can become airborn. Sufferers experience nausea, vomiting, internal bleeding and organ failure before they die.

Although few people contract Ebola each year, its effects are so swift and devastating that it is often feared that it could be used against humans in an act of terroism.

All previously developed vaccines have relied on injecting intact, but crippled, viral particles into the body.

Long-term storage tends to damage the virus, paralysing the vaccine's effectiveness.

The new vaccine contains a synthetic viral protein, which prompts the immune system to better recognise the Ebola virus, and is much more stable when stored long-term.

The vaccine protects 80% of the mice injected with the deadly strain, and survives being "dried down and frozen," said biotechnologist Charles Arntzen from Arizona State University who was involved in its development.

He said the next step is to try the vaccine on a strain of Ebola that is closer to the one that infects humans.

By Jennifer Carpenter.BBC

Taking slightly more than is recommended can cause significant damage over timeTaking slightly too much paracetamol day after day can be fatal, experts have warned.

A dangerous dose might just be a few pills too many taken regularly over days, weeks or months, they said.

Researchers at Edinburgh University saw 161 cases of "staggered overdose" at its hospital over a 16-year period.

People taking tablets for chronic pain might not realise they were taking too many or recognise symptoms of overdose and liver injury, they said.

The researchers told the British Journal of Clinical Pharmacology that this life-threatening condition could be easily missed by doctors and patients.

Doctors may not initially spot the problem because blood tests will not show the staggeringly high levels of paracetamol seen with a conventional overdose, where someone may have swallowed several packets of the drug.

Patients who have taken a staggered overdose tend to fare worse than those who have taken a large overdose, the study suggests.

Dr Kenneth Simpson and colleagues looked at the medical records of 663 patients who had been referred with paracetamol-induced liver injury to the Scottish Liver Transplantation Unit at the university hospital.

The 161 who had taken a staggered overdose were more likely to develop liver and brain problems and need kidney dialysis or help with their breathing. They were also more likely to die of their complications.

Dr Simpson said: "They haven't taken the sort of single-moment, one-off massive overdoses taken by people who try to commit suicide, but over time the damage builds up, and the effect can be fatal."

Professor Roger Knaggs of the Royal Pharmaceutical Society said patients should heed the warning.

"If people experience pain and paracetamol doesn't help, rather than thinking a 'top up' dose may work, they should consult their pharmacist for alternative pain control or referral to someone who can help with the cause of the pain.

"The message is clear: if you take more paracetamol than is recommended, you won't improve your pain control but you may seriously damage your health.

"At this time of year people should also take care with combination cold and flu products which may have paracetamol as one of the ingredients. It's easy to take more than intended, so if in doubt consult your pharmacist."

Meanwhile, researchers at King's College London and Lund University in Sweden say they have discovered precisely how paracetamol works in the body. It is via a protein on nerve cells called TRPA1, says Nature Communications.

Now that they understand this principal mechanism, scientists can start to look for molecules that work in the same way to effectively relieve pain, but are less toxic and will not lead to serious complications following overdose.