Thursday, August 13, 2009

A Mediterranean diet and regular exercise keeps Alzheimer’s at bay (?)

The usual epidemiological nonsense based on a highly atypical sample. It was probably just the usual class effect that was detected. It was probably middle class people -- who are healthier anyway -- who obeyed the conventional food wisdom by eating their vegetables etc.

People who eat a Mediterranean diet and exercise regularly are at significantly lower risk of developing Alzheimer’s disease, research suggests. A study of more than 1,000 elderly people shows that those who exercised the most and ate a diet rich in fruit, vegetables and fish were 60 per cent less likely to suffer from dementia.

The research, published in the Journal of the American Medical Association, is the first to show a link between the two life style factors and a persons Alzheimer’s risk. The study, conducted by Columbia University Medical School, focused on a community of elderly people in New York with an average age of 77, who were monitored for 5½ years. Standard neurological and psychological tests for Alzheimer’s were undertaken every 18 months. A total of 282 people developed the disease by the end of the study.

Higher physical activity was found to reduce the risk of Alzheimer’s by 33 per cent, while people who had a Mediterranean-style diet rich in fruits, vegetables, cereal and fish, but low in meat and poultry, showed a 40 per cent risk reduction. Participants who both exercised a lot and ate a Mediterranean-style diet had a 60 per cent reduced risk.

Dr Nikos Scarmeas, study leader from Columbia University Medical School, said: “It seemed that the more that they were doing in terms of both diet and exercise, the lower was their risk for the disease. “Often people who exercise also follow a healthy diet and vice versa. We wanted to tease out which of these two behaviours may be associated with lower risk for [Alzheimer’s], or if the combination of the two is associated with decreased risk even further.”

He said even low degrees of physical activity appeared to have a protective effect against Alzheimer’s. It is believed by experts that environmental and genetic factors contribute to the onset of the disease. “We need to understand and learn more about the exact biological mechanisms that may connect physical activity and diet with the biological changes of Alzheimer's disease,” Dr Scarmeas said.

About 60 per cent of the 700,000 Britons suffering from dementia are affected by Alzheimer’s. The number of patients is rising fast.

Dr Susanne Sorensen, Head of research at the Alzheimer’s Society said: “A Mediterranean diet full of green leafy vegetables, oily fish, nuts and low in saturated fats is an incredibly healthy approach to eating and may reduce your risk of developing dementia. This study suggests combining this diet with regular exercise is one of the best ways to cut your chances of developing dementia. “With one million people set to develop dementia in the next 10 years, it is essential that we act now to defeat it.”


New single-dose swine flu drug is found to work as well as Tamiflu

A new, single-dose swine flu drug has been shown to work as well as Tamiflu in large-scale clinical trials, it was announced yesterday. The drug could play a crucial role in preventing flu viruses from becoming drug resistant because of patients not finishing their course of medication for reasons including adverse side-effects.

Avian flu and the ordinary seasonal virus can also be treated. The medication, known as Laninamivir, is taken as a single dose with the same kind of inhaler that is used for asthma. “We see in trials that about 20 per cent of people don’t finish the course of treatment,” said Peter Openshaw, a specialist in respiratory diseases at Imperial College London. The smaller dose also means that Laninamivir will be much easier to stockpile.

It was tested in a thousand patients infected with two types of seasonal flu in Japan. Patients treated with Laninamivir recovered as quickly as those given Tamiflu and had fewer side-effects. A study, published in the journal Nature, showed that the drug was just as effective against swine flu and the H5N1 bird flu virus.

John Oxford, a virology specialist at Queen Mary, University of London, described the result as a “mini-breakthrough” in a long-stated goal for flu treatment, and said that it could not have come at a better time. But he added that swine flu would be around for some time to come. “We’re in for a long haul,” he said.

Laninamivir is manufactured by the Australian company Biota, which expects to submit an application to market the drug in Japan by early next year. The company is seeking a licensing partner to market the drug in the US and Europe. Roche, the Swiss pharmaceutical company, has been suggested as a likely candidate.

Research published by the University of Oxford suggests that the automatic prescription of anti-virals for otherwise healthy patients is not the best policy, as the drugs only reduce the length of illness by one day. However, scientists predict that by next year more old people, who have some immunity to the current virus, will be infected. “Within 18 months it will have mutated and then it will move up the age range,” Professor Oxford said.


Bee venom destroys cancer cells in tests on mice

Bee venom can be engineered to target tumours and could prove an effective future treatment for cancer, a study has found. During a trial, the poisonous chemical in a bee’s sting, melittin, was attached to tiny molecules or “nanoparticles” that then attack and destroy cancer cells, leaving healthy cells intact. The carrier particles, dubbed “nanobees”, were also effective in targeting pre-cancerous cells.

Nanobees could eventually replace conventional therapy for certain types of cancer, according to scientists behind the study, which is published today in the Journal of Clinical Investigation. They said that the treatment would have fewer side-effects than chemotherapy. “The nanobees fly in, land on the surface of cells and deposit their poisonous cargo,” said Professor Samuel Wickline, a specialist in nanomedicine at Washington University in St Louis, who led the research.

The treatment was tested on two groups of mice with cancerous tumours. One group had melanoma skin cancer, the other had been implanted with human breast-cancer cells. After four to five injections of the nanobees, the breast-cancer tumours were 25 per cent smaller, and the melanoma tumours were 88 per cent smaller, compared with untreated mice. The carrier particles used in the study have already been approved for clinical use in various other medical applications. The team plans to begin human trials with the nanobees next year.

They predict that the treatment could be effective in treating a wide range of cancers and that it would have fewer side-effects than chemotherapy. They say the treatment could also be more effective than chemotherapy, because it is more targeted. With chemotherapy, patients are given the largest tolerable dose of medication, but because nanobees specifically attack tumours, doses could be much lower.

Melittin works by attaching itself to the surface of cells and ripping holes in the membrane. “In high enough concentration it can destroy any cell it comes into contact with,” said Professor Paul Schlesinger, a cell biologist at Washington University and a co-author of the paper.

Most cancer treatments target DNA, but cancer cells are frequently able to adapt and develop resistance to DNA damage. It is much harder for cells to defend against damage to the membrane, however, making melittin an attractive treatment. Despite the high toxicity of the bee venom, the mice suffered few side-effects and there appeared to be little damage to non-cancerous cells.

Leaky blood vessels around tumours mean that nanoparticles build up there in high enough quantities to do damage. A chemical tag enhanced this effect by increasing nanobees’ affinity for cancerous cells compared with normal cells. “It’s like molecular Velcro,” Professor Wickline said. “The toxin doesn’t come off the bee until it finds its target.”

If the melittin had been injected into the bloodstream in its normal form it would lead to widespread destruction of red blood cells. But following the nanobee injection, the blood count of mice was normal, and they showed no signs of organ damage.

A concern with some nanomedicines is that nanoparticles are left circulating in the body after treatment. They are biologically inert, meaning they are do not get metabolised and cleared from circulation in the normal way.

The spherical nanobees, which are about six millionths of an inch in diameter, are, however, quickly cleared from the system after treatment. They are made of perfluorocarbon, an inert non-toxic compound used in artificial blood. Once the melittin has been removed from the nanobee, it dissolves and is evaporated in the lungs.


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