Appropriate treatment can all but eradicate the risk that a pregnant woman with HIV will pass the virus to her child, research shows.
Data on 5,151 HIV pregnancies in the UK and Ireland between 2000 and 2006 found an infant infection rate of just 1.2% where preventative steps were taken.
In the mid-1990s, before effective drug therapy became available, the infant infection rate was over 20%.
University College London led the Aids Online study.
The researchers said it was the first time such low rates of infection had been observed at a population level.
Most HIV positive women in the UK now take a combination of antiretroviral therapy (ART) drugs during pregnancy.
A caesarean section delivery reduces the risk of infection to the child - but the latest study showed that in many cases the drugs are so effective that a normal delivery is possible.
Transmission rates for women on ART for at least the last 14 days of pregnancy were 0.8% - regardless of the type of delivery.
The researchers said the key to success was that most women in the UK and Ireland now accepted antenatal testing for HIV.
The introduction of routine screening saw the estimated proportion of infected women diagnosed before delivery rise from about 70% in 200 to about 95% in 2005.
However, a 2006 report from the World Health Organization found that access to ART drugs is severely limited in developing countries.
The authors found that under 10% of pregnant women with HIV in these countries had access to the drugs.
As a result, they calculated, about 1,800 babies were born with HIV each day because their mothers did not get the drugs they need.
Uptake of testing
Lead researcher Claire Townsend said that for women with access to drugs, the findings were "greatly encouraging".
She said: "They demonstrate that if women are tested for HIV early enough in pregnancy for ART to be initiated, the risk of infection to their baby is very low indeed.
"This emphasizes the importance of achieving and maintaining a high uptake of antenatal HIV testing on a national scale."
Lisa Power, of the HIV charity Terrence Higgins Trust, said: "With the right treatment and relevant support, the vast majority of women living with HIV can have healthy uninfected children.
"This is why testing for HIV in pregnancy is so important and why treatment for pregnant women living with HIV in the UK should always be free, whatever their immigration status."
'Outlook worse' for scalp cancer
Skin cancers on the scalp or neck are more deadly than those elsewhere on the body, a large study has suggested.
An analysis of 50,000 cases of melanoma found people with these cancers were nearly twice as likely to die as those with the disease on arms or legs.
Scalp and neck cancers were often found later but there seemed to be something inherently virulent about them, the Archives of Dermatology study found.
Survival rates from skin cancer are nonetheless relatively high.
The five-year survival rate for patients with scalp or neck cancer was 83%, compared with 92% for those with melanomas on the face and ears and on the extremities - the arms, legs, hands and feet.
Extra time
A team at the University of North Carolina School of Medicine found cancers on the scalp and neck appeared to be thicker and were more likely to be ulcerated than cancers at other sites.
The lymph nodes were also more often affected in patients with scalp and neck cancers than in the other skin cancer groups.
The researchers acknowledged that people with cancers in areas likely to be hidden by hair were more likely to spot skin abnormalities later.
But even after this was factored into the analysis, there was a poorer survival rate overall - leading the researchers to conclude that there were biological differences between the cancers
"Only 6% of melanomas present with the disease on the scalp or neck, but those patients account for 10% of melanoma deaths," said Nancy Thomas, a professor of dermatology who led the research.
"That's why we need extra time to look at the scalp during full-skin examinations."
Patients with skin cancers in this area tended to be slightly older - 59 as opposed to an average of 55 in the study - and were more likely to be male.
The British Skin Foundation said the study showed why it was necessary to cover up well when exposing the body to intense sunshine.
"Generally, when people are protecting themselves from the sun, the head and neck do not receive the same attention as the rest of the body," said spokeswoman Indy Rihal.
She added: "You must not ignore your neck and scalp. This new piece of research highlights the importance of this, so make sure that you always wear a wide-brimmed hat to protect your scalp, face and neck too."
Cancer Research UK also welcomed the study.
"Melanomas can grow anywhere on the body so it's crucial to check all areas of your skin regularly for any unusual changes, as the disease is much easier to treat when it's spotted earlier," said Dr Alison Ross.
Brain damage link to cancer drug
A drug widely used to treat cancer may cause brain damage, with the effects lasting for years after the end of treatment, research suggests.
The drug, 5-fluorouracil (5-FU), is used, alongside others, to treat cancers of the breast, ovaries, colon, stomach, pancreas and bladder.
Tests on mice showed it destroys vital cells in the brain that help to keep nerves functioning properly.
The University of Rochester study features in the Journal of Biology.
The researchers say their findings could explain some of the neurological side effects associated with chemotherapy - a phenomenon often known as "chemo brain".
These include memory loss, poor concentration, and in more extreme cases, seizures, impaired vision and even dementia.
Until recently they were often dismissed as the by-products of fatigue, depression and anxiety related both to the diagnosis and treatment of cancer.
But many patients show symptoms: a previous study by the Rochester team found more than 80% of breast cancer patients reported some form of mental impairment after chemotherapy.
Protective sheath
The latest study found 5-FU attacks oligodendrocyte cells in the brain and the precursor stem cells from which they originate.
These cells play a crucial role in the central nervous system, producing myelin, the protective sheath that keeps nerve fibres in working order.
If myelin is not constantly renewed, communication between nerve cells is damaged.
The researchers showed that oligodendrocytes virtually disappeared from the brains of mice six months after the animals were treated with 5-FU.
Lead researcher Dr Mark Noble said: "It is clear that, in some patients, chemotherapy appears to trigger a degenerative condition in the central nervous system.
"Because these treatments will clearly remain the standard of care for many years to come, it is critical that we understand their precise impact on the central nervous system, and then use this knowledge as the basis for discovering means of preventing such side effects."
The latest study builds on previous work by the Rochester team, which found that three widely used chemotherapy drugs were more toxic to healthy brains than the cancers they were supposed to treat.
Martin Ledwick, of the charity Cancer Research UK, stressed the study had been carried out on animals, and that more work would be needed before any firm conclusions could be drawn on the effect on cancer patients.
He added: "It must be remembered that this drug (5-fluorouracil) can offer significant benefits for people who need it which far outweigh the changes which some patients report."
Fears over pro-suicide web pages
People searching the web for information on suicide are more likely to find sites encouraging the act than offering support, a study says.
Researchers used four search engines to look for suicide-related sites, the British Medical Journal said.
The three most frequently occurring sites were all pro-suicide, prompting researchers to call for anti-suicide web pages to be prioritised.
Mental health campaigners said such sites preyed on vulnerable people.
Unlike in some countries, pro-suicides sites are not banned in the UK.
The 1961 Suicide Act says it is illegal to aid, abet, counsel, procure or incite someone to kill themselves.
But to be successfully prosecuted the individual has to have knowledge and participated in the suicide.
The researchers, from Bristol, Oxford and Manchester universities, typed in 12 simple suicide-related search terms into the internet engines.
They analysed the first 10 sites in each search, giving a total of 480 hits.
Altogether 240 different sites were found. A fifth were dedicated suicides sites, while a further tenth were sites that gave factual or jokey information about suicide.
Meanwhile, 13% of sites were focused on suicide prevention while another 12% actively discouraged it.
Prevent
Lead research Lucy Biddle said that because of the law, self-regulation by internet providers and the use of filtering software by parents were the main methods used to try and prevent use of pro-suicide sites.
But she added: "This research shows it is very easy to obtain detailed technical information about methods of suicide."
She said internet service providers could pursue strategies that would maximise the likelihood that sites aimed at preventing suicide are sourced first.
Marjorie Wallace, chief executive of the mental health charity Sane, agreed something should be done.
"We remain deeply concerned about the possible influence of the internet on suicide rates, not least the ease with which information about particular methods can be found with a simple web search.
"These sites are preying on vulnerable and lonely people."
But the UK Internet Service Providers Association said it did not have editorial control over site prioritisation and would only take sites down if they were illegal.
'Six-way' kidney transplant first
US doctors have carried out what is believed to be the world's first simultaneous six-way kidney transplant.
Six recipients received organs from six donors in operations at the Johns Hopkins Hospital in Maryland.
The procedure was made possible after an altruistic donor - neither a friend nor relative of any of the six patients - was found to match one of them.
Five patients had a willing donor whose kidney was incompatible with theirs, but it did match another in the group.
This meant that suddenly, there were six people who could receive an organ.
The operations were carried out simultaneously to make sure no-one backed out after their loved one had received a kidney.
"All 12 are doing great, the six kidneys are working well," said Dr Robert Montgomery, director of the transplant centre at the Johns Hopkins hospital.
Team effort
The hospital has been one of the pioneers of this system which matches up several groups of people at one time.
It aims to circumvent the problem of altruistic donors ending up in arbitrary allocation systems where only a single patient's needs are served.
The hospital has been carrying out these simultaneous transplants for three years: in 2005, the first triple procedure was performed, a year later, the first five-way.
Nearly 100 medical professionals were needed to make the complex series of transplants possible, from immunogeneticists to hinder rejection to psychologists.
If all goes to plan, each patient can expect their new kidney to last for as long as 20 years.
Recipient Jeanne Heise, whose husband donated to another patient, said more people should know about the system.
"The waiting list for a kidney is very long and too many people die while waiting," she said. "With this group procedure, more and more people can beat kidney disease and live long productive lives."
The UK has so far carried out only two-way transplants, with the most recent - the third - just this week. The prospect of three-way transplants is currently being examined.
A spokesman for UK transplant welcomed the news that the US had achieved a six-way procedure, but said the organisation and logistics required for such a process meant it was still a "very long way off" for the UK.
Cleaning 'improves mental health'
Working up a sweat while performing household chores may not just improve the cleanliness of your home, but your mental health too, a survey suggests.
Just 20 minutes of sustained exercise a week - from cleaning to jogging - can impact upon depression, the British Journal of Sports Medicine study found.
The more strenuous and frequent the activity, the greater the effect.
University College London researchers looked at a survey of 20,000 people on weekly exercise and state of mind.
Another study in the journal also found such exercise among the middle-aged and elderly may delay the ageing process.
No gentle dusting
The more active they were, the less likely they were to be suffering in this way. Taking part in sports at least once a week lowered the risk by 33%, while housework and walking could cut it by as much as 20%.
However, light dusting or meandering to the bus stop strictly did not count.
The activity needed to be for at least 20 minutes at a time, and had to induce breathlessness.
One theory as to why activity might work is that it curbs some biological risk factors for depression, including glucose intolerance, inflammation and cardiovascular problems.
Researchers did however concede they were unable to work out the nature of the relationship, and that those with mental health problems may be less likely to exercise in the first place.
"Many studies suggest benefits for mental health from exercise, and for the first time we have been able to quantify the amount of activity which seems to make a difference," said Mark Hamer of University College London.
"But it is a chicken and egg issue - as those who suffer from stress or anxiety may be less likely to take part in physical activity in the first place."
Sane, the mental health charity, noted that the reasons for distress were often poorly understood and that in severe cases people needed to seek professional help.
But "this study may offer hope to those suffering mental pain that small, manageable lifestyle changes can improve mental wellbeing", said spokesman Richard Colwill.
"The brain is as much a 'physical' organ as the heart or lungs, so perhaps it should not come as a surprise that even little amounts of regular exercise can begin to reduce psychological distress."
Staying active
Another study finds that even if the relationship between strenuous activity and mental health is unclear, those who opt for it may enjoy a more independent old age.
Regular aerobic exercise in middle-age and beyond trains the body to use oxygen more effectively in generating energy, researchers at the University of Toronto found after looking at 400 adults aged between 55 and 85.
This in turn seems to delay biological ageing by as much as 12 years.
Lorna Layward, research manager at Help The Aged, said it was "never too late" to start exercising.
"When people hear the word 'aerobic' they tend to think of Lycra and tracksuits, but there are all sorts of activities from dancing to swimming that can make a huge difference.
"There has long been the assumption that retirement is about putting your feet up, but gradually we're getting the message across that keeping active is good for you in so many ways."
Depression linked to Alzheimer's
People who have had depression may be more prone to Alzheimer's disease, two studies suggest.
Dutch researchers found Alzheimer's was 2.5 times more likely in people with a history of depression.
It was four times more likely in people with depression before aged 60. Dutch and US research appeared in Neurology and Archives of General Psychiatry.
The Dutch study was small - 486 people over an average of six years, with just 33 people developing Alzheimer's.
The researchers, from the Erasmus University Medical Center in Rotterdam, said more work was needed to fully understand the link between Alzheimer's and depression.
Lead researcher Dr Monique Breteler said: "We don't know yet whether depression contributes to the development of Alzheimer's disease, or whether another unknown factor causes both depression and dementia."
One theory is that depression leads to the loss of cells in two areas of the brain, the hippocampus and the amygdala, which then contributes to Alzheimer's disease.
However, the latest study found no difference in the size of these two brain areas in people with depression and people who had never developed the condition.
Second study
The findings were echoed in a second study by Rush University in the US published in Archives of General Psychiatry.
The researchers followed more than 900 members of the Catholic clergy for up to 13 years during which time 190 developed Alzheimer's.
They found that those with more signs of depression at the start of the study were more likely to develop Alzheimer's.
But there was little evidence of an increase in depressive symptoms during the early stages of disease.
Even after the diagnosis of Alzheimer's was made there was no general increase in depression, but rather an increase that was confined to individuals with certain personality traits.
The researchers said their findings suggested that depression was a risk factor for Alzheimer's disease - rather than a subtle early sign of its underlying pathology.
Researcher Dr Robert Wilson said: "Depressive symptoms may be associated with distinctive changes in the brain that somehow reduce neural reserve, which is the brain's ability to tolerate the pathology associated with Alzheimer's disease."
Rebecca Wood, of the Alzheimer's Research Trust, said the research was interesting, and potentially useful.
She said: "Identifying people at higher risk could lead to ways to reduce the number of people who develop dementia, help researchers to understand more about dementia and create new avenues of research."
Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: "More research is needed to clarify the relationship between dementia and depression and determine whether depression causes changes in the brain that make dementia more likely."
Anti-HIV drug 'heart attack risk'
A popular anti-HIV drug nearly doubles the risk of heart attack, a study says.
Abacavir works by reducing the amount of the virus in the body and is often used in combination with other drugs.
But Danish researchers said patients may wish to consider changing treatment programmes after studying over 33,000 people, the Lancet reported.
Experts said the research revealed a new risk, but said benefits of the drug may still outweigh risks. The makers said they took the findings seriously.
The Copenhagen University-led team looked at a range of anti-HIV drugs.
All were found to have no effect on heart attack risk with the exception of abacavir and didanosine, which is not commonly used in the UK and had a much smaller risk than abacavir.
The risk was not cumulative and, therefore, individuals who had stopped using the drugs were found to have no increased risk within six months.
The researchers were unsure why the effect was seen.
But they said their findings posed a dilemma for patients and doctors.
Lead researcher Jens Lundgren said: "If the decision is made to consider discontinuation of either drug, then a full assessment of the possible risks and benefits of their continued use should be undertaken.
"Such an assessment must be individualised for each patient.
"It should take into account their underlying risk of heart attacks, the availability of other treatment options after taking into account their history of past treatment and HIV resistance testing, and the safety profile of alternative HIV medication."
Risk
Dr Didier Lapierre, of GlaxoSmithKline, the manufacturers of abacavir, said the company's own analysis of 54 studies did not suggest a heart risk.
But he added: "GSK takes the finding seriously and is committed to understanding these data more fully and to communicating openly with treating physicians and regulatory agencies globally."
Roger Pebody, treatment advisor at the Terrence Higgins Trust, said: "Heart disease is an issue for many people with HIV, and this important research highlights a risk that hasn't been identified before.
"When deciding the best treatment for each individual this research should be taken into account along with other risk factors like family history, smoking and lack of exercise.
"Some people taking abacavir may choose to change their treatment, but others may decide with their doctor that it's still the best option for them."
Breech birth parents 'carry gene'
Some babies are born bottom-first because of genetic traits inherited from either their mother or father, Norwegian researchers have said.
Fewer than one in 20 is delivered this way up, but a natural breech birth carries extra risks to the child.
A study of 387,000 births, in the British Medical Journal, found a baby had double the chance of being breech if their mother or father was too.
But midwives said parents should not worry too much.
As many as one in four babies are in the wrong position at the mid-point of pregnancy, but all but 3% or 4% are head-down by the time they are delivered.
The precise reasons why a baby might be in the breech position are not known, although the anatomy of the mother - in particular the shape of her womb - can play a strong role.
Babies are designed to be born head-first, and coming out the other way round increases the chance of breathing problems at the moment of delivery.
For this reason, many women with full-term breech babies opt for caesarean sections.
Gene trait
The researchers from the University of Bergen looked at the records of more than 387,000 parents and their first-born children born between 1967 and 2004.
They found an identical increase in risk passed from both male and female parents born in breech position.
While a mother might be able to pass on the increased risk through inherited differences in her physical makeup, any risk passed from a father raises the possibility of a genetic trait carried by the baby rather than the mother.
However, other specialists say the picture is less clear.
Professor Janet Hardy, from the University of Massachusetts Medical School, said that there could be a separate, undetected factor that was increasing the chance of a breech birth in these families.
She said: "Clinicians should continue to gather information during early prenatal care on maternal and paternal birth presentation and other potential risk factors for breech delivery."
Antenatal care
Mervi Jokinen, from the Royal College of Midwives, said the findings were "intriguing".
"We always tend to ask mothers if they know how they were delivered, and some midwives will ask the partners as well, just to record this in the notes.
"But on the whole, women should not be too concerned about the possibility of a breech baby, as long as she is receiving proper ante-natal care."
Henry Annan, a spokesperson for the Royal College of Obstetricians and Gynaecologists, said that having a breech delivery approximately doubled the risks of complications to the baby.
"Having a breech baby does increase the dangers, although, with proper management, the chances are that the baby will be born healthy.
"I think a lot of parents will be unaware of whether they were born breech or not, but this is still an interesting study."
HRT 'might ward off Alzheimer's'
Hormone replacement therapy (HRT) may protect post-menopausal women against memory loss and Alzheimer's disease.
A study found women's memories are affected when their bodies stop producing the hormone oestrogen - as happens at the menopause.
However, the Institute of Psychiatry at King's College London found memory recovered when hormone supplies were restored - the effect achieved by HRT.
Women have a higher risk of developing Alzheimer's than men.
It is estimated that around 450,000 women in the UK have the disease.
There is a theory that oestrogen may help prevent the build up of damaging protein tangles in the brain which are thought to trigger cell death, and Alzheimer's.
But when supplies of the hormone are abruptly cut at the menopause, women may become more vulnerable.
A major US study found no evidence of a protective effect from HRT - and even suggested the combined form of the treatment might increase the general risk of dementia.
The trial was halted early when when results suggested some women taking HRT had an increased risk for breast cancer and cardiovascular disease.
However, UK experts argue that this study focused on older women, who did not receive HRT immediately after the menopause.
Fibroid surgery
The latest research was carried out on 30 young, pre-menopausal women who were having surgery for benign womb growths called fibroids.
The patients were given a drug which shrinks the fibroids, but which also temporarily shuts down the ovaries, producing a state similar to the menopause.
Each woman was given a memory test before, during and after treatment, when their ovaries were once again producing oestrogen.
Average scores were similar before and after treatment, but dipped by about 10% while the women's ovaries were shut down.
The researchers also recorded reduced levels of activity in an area of the brain called the pre-frontal cortex during treatment, which is linked to learning and memory.
Lead researcher Dr Michael Craig said evidence was growing that sex hormones, such as oestrogen, did have a direct effect on the brain.
He said: "There may be a critical window of time around the menopause when HRT may have a beneficial effect in protecting against Alzheimer's dementia.
The Alzheimer's Society said HRT could not be viewed as a treatment option for reducing risk or delaying the onset of Alzheimer's disease.
It said although some previous research had also linked HRT to a lower risk of Alzheimer's, this could be because women taking HRT were also doing other things to preserve their health, and reduce their risk.
Professor Clive Ballard, the society's director of research, said: "Using HRT as a treatment or preventative measure against Alzheimer's disease would mean giving drugs, which can produce side-effects, to women without symptoms."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "This is not conclusive evidence and women are not advised to start HRT specifically to protect against dementia since it can have side-effects and possibly increase the risk of stroke."
Cod oil 'cuts arthritis drug use'
A daily dose of cod liver oil can cut painkiller use in patients with rheumatoid arthritis, a study suggests.
Taking 10g of cod liver oil a day reduced the need for non-steroidal anti-inflammatory drugs (NSAIDs) by 30%, Dundee University researchers say.
Concerns about side-effects of NSAIDs has prompted research into alternative.
Rheumatologists said the study, in Rheumatology journal, funded by Seven Seas, was small but showed fish oil could benefit some patients.
Patients in the trial were either given cod liver oil or placebo and after 12 weeks asked to gradually reduce their use of NSAIDs, such as ibuprofen.
Almost 60 patients completed the nine-month trial which found 39% taking cod liver oil reduced their daily dose of NSAIDs compared with 10% taking a placebo.
The reduction in drug use was not associated with any worsening of pain or the disease, the researchers reported.
The research team at the University of Dundee have now completed three studies which have all shown patients are able to cut down their NSAID use when taking cold liver oil.
It is thought fatty acids in the fish oil have anti-inflammatory properties.
Side-effects
Some side-effects of NSAIDs, such as an increased risk of stomach bleeding have been known for a long time.
But more recently, concerns have been raised about an apparent increased risk of heart attacks and strokes in those taking the drugs.
Study leader Professor Jill Belch said the study offered hope to many rheumatoid arthritis patients who wanted to reduce the amount of pain medication they take.
"Every change in medication should be discussed with a GP but I would advise people to give cod liver oil a try for 12 weeks alongside their NSAIDs and then try to cut it down if they can manage it but if they don't manage it, that's fine.
"If you can get off NSAIDs it will be much safer."
National Rheumatoid Arthritis Society chief executive Ailsa Bosworth said: "People with rheumatoid arthritis still rely heavily on NSAIDs, even though the safety of these drugs is under scrutiny.
"We look forward to more research in this area."
British Society for Rheumatology president Dr Andrew Bamji said it was a small study so difficult to draw firm conclusions.
But he added: "Anything that can help to reduce NSAID use is going to be safer for patients.
"It does look as if the results are positive and that is quite interesting.
"I would say to patients by all means take cod liver oil and when you feel ready start to reduce your NSAID dose."
But he stressed that patients must discuss plans with their doctor because it was important that physicians were aware of all medications and supplements the patient was taking.
Wheeze 'link' to baby milk powder
Prolonged exposure to baby milk powder increases the risk of breathing problems, including wheezing and breathlessness, a study has found.
It looked at 170 Thai factory workers who made the powder, but the team from University of Birmingham says the risk could also apply to nannies.
Mothers and babies are safe, because they have relatively little exposure.
But the study, published in the European Respiratory Journal, says at-risk workers should be monitored.
It is already known that consuming milk powder can lead to the development of an allergy if a child has an intolerance to cow's milk but the potential risks of inhaling milk powder have never before been studied.
In this research, a team from the Institute of Occupational and Environmental Medicine at the University of Birmingham and Thailand's Mahidol University looked at just under 170 workers in a Thai baby milk factory.
The factory had high hygiene standards, and concentrations of milk powder dust were relatively low.
The majority - 130 - were directly involved in manufacturing and packaging baby milk. Another 22 were responsible for adding vitamins to the milk and 15 were quality controllers.
The researchers compared these workers' health with that of 76 office workers using a questionnaire and lung function tests.
Baking link
Twice as many people who worked with milk powder had symptoms, with 24% experiencing wheezing and 33% having breathlessness compared to 12% and 16% of the office workers.
The difference remained even when the researchers took other factors, such as smoking, into account.
Lung function tests also showed a significant reduction in how strongly milk powder workers were able to breathe out.
Those working with the powder were also found to be twice as likely to have had asthma.
The researchers, led by Dr Maritta Jaakkola, say the results suggest the workers are hyper-sensitive to the powder, rather than simply irritated by it.
Dr Jaakkola said: "The effects of inhaled milk powder are relevant for occupational settings, so workers with such exposure should be protected as much as possible using exposure control measures, such as wearing latex gloves.
"They should also have regular check-ups of their respiratory health.
"Nannies, and bakers, both groups who are exposed to milk powder during their working life, may also benefit from respiratory tests."
But Leanne Male, assistant director of research at Asthma UK said the levels of powder a person would need to be exposed to in order to suffer breathing problems would have to be high, and reassured mothers they would not be affected.
Ms Male said the risk was highest for people who manufactured the powder.
She added: "This research highlights the dangers of occupational asthma and the need for employers to recognise potential triggers in the workplace."
Cloning treats mouse Parkinson's
Therapeutic cloning has been successfully used to treat Parkinson's disease in mice, US researchers say.
The study in Nature Medicine provides the best evidence so far that the controversial technique could one day help people with the condition.
The Memorial Sloan-Kettering Cancer Centre team say it is the first time animals have been successfully treated with their own cloned cells.
UK experts said the work was promising and exciting development.
No rejection
In Parkinson's disease, nerve cells in the part of the brain that controls muscle movement either die or become impaired.
Normally, these cells produce a vital chemical known as dopamine, which allows smooth, co-ordinated function of the body's muscles and movement.
In therapeutic cloning, the nucleus of a cell is inserted into an egg with the nucleus removed.
This cell then develops into an embryo from which stem cells can be harvested and used as a treatment.
In this study, stem cells were developed into dopamine-producing neurons the missing nerve cells in Parkinson's disease.
The mice that received neurons derived from their own clones showed significant signs of improvement.
But when these neurons were grafted into mice that did not genetically match the transplanted cells, the cells did not survive and the mice did not recover.
The researchers say the therapy is promising because, as the cells originally came from the animal that was ill, they were not rejected by its immune system.
'Great hope'
Scientists are pursuing the use of stem cell therapy for Parkinson's disease because it would allow the replacement of the dead dopamine-producing nerve cells with new, healthy cells.
This should restore the supply of dopamine within the brain and allow it to work normally again.
However, the challenge has been to produce nerve cells which can survive after transplantation.
Dr Kieran Breen, director of research and development at the Parkinson's Disease Society said: "This is an exciting development, as for the first time, we can see that it may be possible to create a person's own embryonic stem cells to potentially treat their Parkinson's.
"Researchers in this area now need to carry out more studies to satisfy safety concerns and to make the process more efficient before these studies are carried out on people living with Parkinson's."
He added: "Stem cell therapy offers great hope for repairing the brain in people with Parkinson's.
"It may ultimately offer a cure, allowing people to lead a life that is free from the symptoms of Parkinson's."
Professor Robin Lovell-Badge, an expert in stem cell research at the National Institute of Medical Research, said this was good research which showed using therapeutic cloning could be beneficial.
"There was a very significant level of recovery.
But he added: "They only studied the mice for 11 weeks afterwards, which is not a huge amount of time to see how persistent the repaid would be."
However, the experts said much more research in both animals and humans was needed before the treatment could be offered to people with Parkinson's.
In a separate study, a team from University College London have discovered mutations in a gene which may trigger Parkinson's in people with a family history of the condition.
The finding could provide scientists with a clue as to what causes Parkinson's - and could contribute to the search for new treatments.
'Killer' marrow transplant hope
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.
Bone marrow transplantation has been around for half a century, and, in leukaemia, is traditionally given to patients to replace bone marrow destroyed by powerful anti-cancer treatments.
One of the biggest problems in bone marrow transplantation is when the immune cells in the donated bone marrow "reject" their new host.
They launch attacks which can prove fatal in the worst cases, a condition called "graft versus host disease".
To avoid this, patients and donors are carefully screened to produce as perfect a match as possible.
However, some of the most recent research in bone marrow transplantation focuses on using the disease-fighting qualities of bone marrow to destroy cancer cells, either to prevent the disease coming back or to tackle it head-on, even where it is resistant to drugs and other treatments.
Testing for killers
Professor Andrea Velardi, from the University of Perugia in Italy, has been funded by the Anthony Nolan Trust to look for ways to harness these qualities without raising the risk of graft versus host disease.
He has been using donors from the patient's own family who are only a partial match - sharing only 50% of their genetic material.
He found that in some cases, immune cells called "natural killer" cells were active in the donor bone marrow after transplantation, and could launch an effective attack on the leukaemia cells, and that he could predict in advance, using tests, how effective that would be.
In a small group of patients with acute myeloid leukaemia - which makes up approximately a third of all cases - survival rates improved when this kind of transplant was given with the patient already "in remission" - cleared of the disease by chemotherapy.
However, it significantly increased survival - from 2% to 30%, among those patients whose disease had not responded fully to treatment prior to the transplant.
He said: "For patients considered ineligible because of chemo-resistant leukaemia, this is a potentially life-saving advancement.
"It's likely to make enormous changes in the practice of transplantation worldwide."
He said that there were some patients - approximately a third of the population - who could not benefit from the technique, because of a physical makeup which meant that their leukaemia would not respond to the natural killer cells.
In addition, he said, the chances of finding a donor with suitable cells was approximately 50% in the average family size.
Cautious welcome
Other experts welcomed the research, although were cautious about the implications of the findings.
A spokesman for the Leukaemia Research Fund said that, while exciting, more evidence would be needed that the treatment was effective in bigger trials against all types of leukaemia.
In particular, it should be tested on older patients, who make up a large proportion of those whose disease had failed to respond to conventional treatment.
However, he said: "I don't want to underestimate the importance of this work.
"If you are in the position of a patient who has not responded to treatment, the choice between a 2% chance of survival and a 30% chance is not a difficult one."
Professor Velardi's work is due to be presented at a bone marrow transplantation research conference in London next week.
Brown criticised over embryo bill
The leader of the Catholic church in Scotland has urged Gordon Brown to rethink "monstrous" plans to allow hybrid human-animal embryos. Cardinal Keith O"Brien will use his Easter Sunday sermon to launch a scathing attack on the government is controversial proposals.
He will also call on the prime minister to allow Labour MPs a free vote on the issue at Westminster.
Mr Brown has said the bill would improve research into many illnesses.
Supporters of the Human Fertilisation and Embryology Bill believe hybrid embryos could lead to cures for diseases including multiple sclerosis and Alzheimer"s disease.
Speaking at Prime Minister is Questions on Wednesday, Mr Brown said: "This is an important bill that improves the facilities for research and is vital for dealing with life-threatening diseases."
But in his sermon, which was released on Friday, Cardinal O"Brien will claim that the bill would lead to the endorsement of experiments of "Frankenstein proportions".
He will say: "This bill represents a monstrous attack on human rights, human dignity and human life.
"In some European countries one could be jailed for doing what we intend to make legal.
"I can say that the government has no mandate for these changes: they were not in any election manifesto, nor do they enjoy widespread public support."
The cardinal will describe the practice as "grotesque" and "hideous".
He will add: "One might say that in our country we are about to have a public government endorsement of experiments of Frankenstein proportions - without many people really being aware of what is going on."
Free vote
Cardinal O"Brien will go on to call for the establishment of a "single permanent national bioethics commission".
He has written to Mr Brown to tell him that this would be the only way in which the issue could be "adequately discussed".
A proposed amendment to the bill, which would have prohibited the creation of inter-species embryos - known as human admixed embryos - was defeated by 268 votes to 96 in the House of Lords in January.
Labour peers were instructed to follow the party whip by voting against the proposed amendment.
Conservative leader David Cameron has called on Mr Brown to allow Labour MPs to have a free vote on the bill when it returns to the House of Commons later in the year.
Free votes allow MPs to vote according to their own beliefs rather than following the party whip.
Mr Brown has said a decision on whether a free vote will be held will be taken "in due course".
