Natural killer (NK) cells are white blood cells which home in on infected or cancerous cells, releasing agents that induce apoptosis, or "cell suicide". NK cells are especially active against viruses.

The research emerged from findings that stress and depression impair NK cell function and can accelerate the progress of HIV/ Aids. Scientists recruited depressed and non-depressed HIV-positive women and treated them with three drugs to treat stress and depression. Two, Citalopram and the "substance P antagonist" CP-96345 increased NK cell activity, while RU486 had no effect.

Some leukaemia patients who do not respond to conventional treatments may benefit from bone marrow transplants selected to target the cancer directly.

The technique, pioneered in Italy, uses transplants from family members who are not a perfect match.

"Natural killer" cells in the new bone marrow then attack the leukaemia.

Survival rates rose after the treatment, but UK experts say these need to be reproduced on a bigger scale and in different types of the disease.

The virus is endemic in Java, Sumatra, Bali and southern Sulawesi with sporadic outbreaks reported from other areas, the FAO said.

By June 2008, more than 2,000 surveillance and response teams will be active in more than 300 districts in areas of the country where the disease is endemic, Mr Domenech said.

But that may not be enough.

"Indonesia is facing an uphill battle against a virus that is difficult to contain. Major human and financial resources, stronger political commitment and strengthened co-ordination between the central, provincial and district authorities are required to improve surveillance and control measures," Mr Domenech said.

One in 150 people infected with West Nile virus get severe neurological disease. More than 40% of these patients may have serious symptoms for the rest of their lives, say Kristy Murray, PhD, DVM, University of Texas Health Science Center at Houston, and colleagues.

The finding comes from five years of data on 108 Houston-area residents who came down with severe West Nile disease after infection with the mosquito-borne virus. Murray's team evaluated the patients every six months.

A year after their West Nile virus infection, 60% of these patients still had serious symptoms. Five years later, 42% had not fully recovered - and weren't getting any better.

These lasting symptoms included fatigue, muscle weakness, depression, difficulty walking, memory loss, and personality change.

The participants were randomly assigned to receive either sublingual immunotherapy in the form of honeybee venom drops placed under the tongue, or placebo drops.

Patients in the immunotherapy group got escalating doses of honeybee venom for six weeks, followed by a maintenance dose, given three times a week for six months.

"You hold the drop under the tongue for about one or two minutes, then swallow," Passalacqua says.

Then came the bee sting challenge. "We put insects in a jar and then put the jar on the patient's forearm" and looked to see what happened, he says.

It worked. The median diameter of the sting wheals in patients given sublingual immunotherapy dropped from about 8 to 3 inches. Looked at another way, wheal diameter was reduced by more than 50% in more than half of them.

"This was a very apparent and very significant reduction in the size of the reaction to the sting," Passalacqua says.

In contrast, there was no change in wheal diameter in the placebo group, and one person broke out in hives.

Neuroanatomist Jill Bolte Taylor had an opportunity few brain scientists would wish for: One morning, she realized she was having a massive stroke. As it happened -- as she felt her brain functions slip away one by one, speech, movement, understanding -- she studied and remembered every moment. This is a powerful story about how our brains define us and connect us to the world and to one another.

A vast array of pharmaceuticals - including antibiotics, anti-convulsants, mood stabilizers and sex hormones - have been found in the drinking water supplies of at least 41 million Americans, an Associated Press investigation shows.

To be sure, the concentrations of these pharmaceuticals are tiny, measured in quantities of parts per billion or trillion, far below the levels of a medical dose. Also, utilities insist their water is safe.

But the presence of so many prescription drugs - and over-the-counter medicines like acetaminophen and ibuprofen - in so much of our drinking water is heightening worries among scientists of long-term consequences to human health.

People take pills. Their bodies absorb some of the medication, but the rest of it passes through and is flushed down the toilet. The wastewater is treated before it is discharged into reservoirs, rivers or lakes. Then, some of the water is cleansed again at drinking water treatment plants and piped to consumers. But most treatments do not remove all drug residue.

Even users of bottled water and home filtration systems don't necessarily avoid exposure. Bottlers, some of which simply repackage tap water, do not typically treat or test for pharmaceuticals, according to the industry's main trade group. The same goes for the makers of home filtration systems.

Now researchers in Germany say that the rapidly vibrating tattoo needle could be a useful way of delivering vaccines under the skin instead of insoluble ink.

In studies with mice, tattooing a vaccine produced 16 times more antibodies than a simple injection into muscle tissue.

The level of antibodies indicates the strength of the immune system's response.

Dr Martin Mueller, one of the researchers behind this work, says that the greater damage to the body caused by the tattoo needle may explain the better immune response.

From blood vessels to muscle tissue, Atala and his team at Wake Forest University believe that in theory anything inside the body can be grown outside the body, CBS News correspondent Wyatt Andrews reports. And it's real: They've made 18 different types of tissue so far.

"That's a heart valve?" Andrews asked.

Atala said: "This is an engineered heart valve."

What he pointed to was a pulsing heart valve to be transplanted into a sheep.

"When people ask me 'what do you do,' we grow tissues and organs," he said. "We are making body parts that we can implant right back into patients."

Once considered a Frankenstein fantasy, the field of regenerative medicine is on the verge of unimagined breakthroughs. Scientists believe every part of the body has cells capable of regeneration - all researchers need to do is isolate those cells and coax them to grow.

He found active smokers and ex-smokers to be the most at risk, although the risk is reduced for people who quit smoking.

Drinking alcohol was also a high risk factor, particularly for people who also smoke, although Stewart said no specific type of alcoholic drink was most strongly to blame.

Drinking chlorinated water and using a mobile phone was far less likely to cause cancer, Stewart said, although the risks associated with the long-term use of mobile phones had not been fully established.

He said there little risk from drinking coffee, using deodorants, drinking fluoridated water and having breast implants or dental fillings.

Dr Dougal claims that only ten minutes under the hat a day is enough to have an effect.

"Currently all you can do with dementia is to slow down the rate of decay - this new process will not only stop that rate of decay but partially reverse it," he said.

Low level infra-red red is thought to stimulate the growth of cells of all types of tissue and encourage their repair. It is able to penetrate the skin and even get through the skull.

"The implications of this research at Sunderland are enormous - so much so that in the future we could be able to affect and change the rate at which our bodies age," he said.

"We age because our cells lose the desire to regenerate and repair themselves. This ultimately results in cell death and decline of the organ functions - for the brain resulting in memory decay and deterioration in general intellectual performance.

The drug, called Enbrel, is injected into the spine where it blocks a chemical responsible for damaging the brain and other organs.

A pilot study carried out by U.S. researchers found one patient had his symptoms reversed "in minutes".

Other patients have shown some improvements in symptoms such as forgetfulness and confusion after weekly injections over six months.

The study of 15 patients with moderate to severe Alzheimer's has just been published in the Journal of Neuroinflammation by online publishers Biomed Central.

The experiment showed that Enbrel can deactivate TNF (tumour necrosis factor) - a chemical in the fluid surrounding the brain that is found in Alzheimer's sufferers.

The two main U.S. cloning companies, Viagen Inc. and Trans Ova Genetics, already have produced more than 600 cloned animals for U.S. breeders, including copies of prize-winning cows and rodeo bulls. They agreed to USDA's call for a continued moratorium Tuesday, but stressed that it applied only to clones themselves, not those animals' conventionally produced offspring, which can begin selling immediately.

The FDA spent six years tracking the safety of cloning, and its decision was long expected, but it came after an emotional fight by opponents. Congress passed legislation last month urging further study of the issue, a call echoed by consumer advocates who also asked that foods from cloned animals be labeled as such.

Their objections aren't just about food safety but also include animal welfare since many attempts at livestock cloning still end in fatal birth defects.

"If you have moral objections to a particular food, or ethical objections to them, FDA's saying, 'Tough, you've got to eat it,'" said Carol Tucker-Foreman of the Consumer Federation of America, who pledged to push for more food producers to shun clone-derived ingredients.

"The FDA did not give adequate consideration to the welfare of these animals or their surrogate mothers," said Wayne Pacelle of the Humane Society of the United States.

The rate of new cases being confirmed has reached the levels of reports during the massive outbreak five years ago, when officials announced an epidemic.

Norovirus can prove deadly for vulnerable people, such as children and the elderly. The impact of the bug has been exacerbated by a new outbreak of flu with those most at risk now being given antiviral drugs by their doctors.

NHS Direct, which patients can telephone for health advice, has been inundated with people calling with symptoms of the norovirus.

Helen Young, the clinical director, said: "We are seeing an increasing number of calls about diarrhoea and vomiting. Norovirus is a major issue for the whole NHS right now and we urge anyone who has symptoms to engage in good hygiene to prevent it spreading further and to drink plenty of fluids."

The number of reports of norovirus is expected to rise over the next six weeks, as children return to school and employees head back to work after the Christmas break.

Minimally invasive surgery has obvious advantages - it can mean smaller scars, reduced hospital stays and shorter recovery times.

Surgeons are also looking at ways to avoid skin incisions altogether.

One approach is Natural Orifice Transluminal Endoscopic Surgery or Notes. This means operating in the peritoneal space through natural orifices or cavities, such as the bowel.

Lord Darzi said: "The unrivalled imaging and sensing capabilities coupled with the accessibility and sensitivity of i-Snake will enable more complex diagnostic and therapeutic procedures than are currently possible.

A nasal spray containing a naturally occurring brain hormone called orexin A reversed the effects of sleep deprivation in monkeys, allowing them to perform like well-rested monkeys on cognitive tests. The discovery's first application will probably be in treatment of the severe sleep disorder narcolepsy.

The treatment is "a totally new route for increasing arousal, and the new study shows it to be relatively benign," said Jerome Siegel, a professor of psychiatry at UCLA and a co-author of the paper. "It reduces sleepiness without causing edginess."

Orexin A is a promising candidate to become a "sleep replacement" drug. For decades, stimulants have been used to combat sleepiness, but they can be addictive and often have side effects, including raising blood pressure or causing mood swings. The military, for example, administers amphetamines to pilots flying long distances, and has funded research into new drugs like the stimulant modafinil (.pdf) and orexin A in an effort to help troops stay awake with the fewest side effects.

Uganda has 101 suspected cases of Ebola fever and hundreds more people being closely monitored, officials said on Friday, as fear grew in Uganda and neighbouring countries that the deadly virus might spread.

Twenty two people have so far died of the fever and Minister of State for primary health-care Dr. Emmanuel Otaala told journalists 11 health workers have fallen sick.

"Cumulatively, we have 101 cases," he said.

Another 338 people are being monitored because they came into contact with those infected by the virulent haemorrhagic fever, which often causes victims to bleed to death through the ears, eyes and other orifices.

All were in western Uganda's Bundibugyo district, except for two in Kampala, including a doctor who died. Otaala said the cabinet had approved a pay increase to compensate health workers taking on the risk of dealing with Ebola.

The new 256-slice CT machine takes large numbers of X-ray pictures, and combines them using computer technology to produce the final detailed images.

It also generates images in a fraction of the time of other scanners: a full body scan takes less than a minute.

The Philips machine was unveiled at the Radiological Society of North America.

Because the images are 3D they can be rotated and viewed from different directions - giving doctors the greatest possible help in looking for signs of abnormalities or disease.

All images also can be accessed on any computer in a hospital or by colleagues and researchers remotely, to make it easier for the whole team to share information.