Cancer, How it is diagnosed and treated

11 January 2004
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New source of anti-microbials for hospital superbugs, piranah attacks on the increase in Brazil, low tar cigarettes as bad as higher tar, garlic-based anti-cancer smart-bomb, cancer magic-bullet for lymphoma, an interview with Beagle 2 co-ordinator Prof. Colin Pillinger, and special guests Simon Cotton, demonstrating a skin scanner for the rapid diagnosis of melanoma, and skin cancer expert Dr. Fiona Watt - "what is cancer, what causes it and how can we treat it ?"

In this episode

Novel Source of Antimicrobials

Researchers looking for new ways to deal with antibiotic resistant infections may have discovered a bacterial achilles heel. Analysing the genetic code of one superbug, methicillin-resistant Staphylococcus aureus (MRSA), Nicholas Mann and his team at the University of Warwick have found that these bacteria carry DNA coding for bacterial viruses, called bacteriophages, that can selectively kill this type of bacteria. These bacteriophages normally remain in a dormant state, hiding within the genome, and are not normally lethal to the bacteria. But by isolating rare mutants of the bacteriophages, the researchers have produced 10 new types of phage which can selectively infect and kill MRSA. They plan to commercialise their discovery with the production of wound dressings impregnated with their new bacteriophages, to stop any rogue bacteria gaining a foothold. It may also be possible to use these phages in a nose-spray to reduce Staphylococcus aureus carriage among hospital staff and patients.

Piranah Attacks Are on The Increase in Brazil

A recent spate of piranha attacks on swimmers in South East Brazil could be caused by rivers being dammed. In one town called Santa Cruz of Conceircao, there had been no reported injuries from those toothy fish until 4 years ago when piranha bites started to occur. By 2002 there was a rapid increase in the number of attacks on tourists and locals who like to swim in dammed portions of the stream, with 38 attacks taking place over 5 weekends. The same was happening in other rivers close to dams. The reason is that damming rivers encourages piranha populations to grow, by perhaps as much as 10 times un-dammed levels. Piranhas lay their larvae in submerged or floating waterweeds like water hyacinth, which collect in slow-moving rivers; the conditions created by dams. In un-dammed rivers it's thought that occasional floods would sweep away this vegetation and hep to control piranha populations. Damming is becoming increasingly common in south east brazil due the growing need for flood protection in the heavily populated region of the country. Over the years, numerous grisly stories of people being attacked and eaten by ferocious schools of piranhas have surfaced, but the authors of the new report claim there is little scientific evidence to support such behavior. They say at least three of the people supposedly killed by schools of piranhas actually died from heart failure or drowning and were only eaten by the fish after they were dead.

Low Tar Cigarettes As Bad As Medium Tar

New research from the US has shown that the risk of lung cancer is no different in people who smoke medium, low or even very low tar cigarettes. The researchers looked at the tar-rating of cigarettes smoked over a 6 year period by over 570,000 women and 360,000 men over the age of 30. They found that, obviously, the smokers had a much higher risk of lung cancer compared with non smokers, or people who were ex-smokers, but surprisingly there was no difference in the cancer rates between people smoking medium, low tar or very low tar brands. People who smoked high tar, unfiltered, cigarettes did have a higher cancer rate. The authors explain that people tend to smoke lower tar cigarettes more intensively, to make up for the lower nicotine level in a low tar cigarette, and so any benefit of switching to a lower tar brand seems to be lost.

Rocket Science To Help The Elderly

No, I'm not proposing jet packs to get Granny up the stairs, but researcers at Manchester Metropolitan Universtiy think that methods invented to help astronauts cope with life in space might help the elderly. When astronauts are in space, they live under reduced gravity and are relatively inactive- something that leads to muscle wasting. This muscle loss is very similar to that seen as people get older, often because they are quite inactive. The Manchester team started testing older people twice a week on an exercise machine known as a yo-yo machine, designed for use in the International Space Station. They found a significant improvement in the physical performance of the people who had done the exercises, suggesting that the astronaut training really does work to improve strength, mobility and quality of life in the elderly.

Garlic Smart-bomb For Targeted Cancer Therapy

Chemicals found in Garlic could be used as a new Smart Bomb to treat cancer. Allicin is a toxic chemical which is not present in whole cloves of garlic, but is produced in a reaction between two other chemicals held in separate compartments in each clove- these are an enzyme called alliinase and a harmless compound called alliin. When the clove is broken and the membranes separating the two chemicals are broken, they react with each other to form allicin. We're not poisoned when we eat garlic because although Allicin is toxic it is also very unstable and breaks down quickly and harmlessly when eaten. Researchers from Isreal decided to try and recreate this reaction at the site of cancerous tumours. They did this by binding the enzyme to antibodies, which have been programmed to recognise distinctive receptors on the surface of tumour cells. When the antibodies are injected into the blood stream they seek out and bind to cancer cells. The other chemical alliin is then also injected, and where it encounters the enzyme, the toxic chemical allicin is produced which penetrates and kills the tumour cells. Healthy cells nearby are not affected by allicin because they haven't attracted any antibodies. The technique has already been used to successfully block the growth of stomach tumours in mice and researches think the treatment should work for most types of cancer, as long as specific antibodies can be designed to recognise receptors unique to the particular type of cancer cells.

New Anticancer Magic Bullet

Doctors in America have pioneered a new treatment for lymphoma, a type of cancer of the blood, that can selectively home in on cancer cells whilst leaving the rest of the bodies' tissues unharmed. This is a big step forward in cancer treatment because many traditional cancer therapies involve giving drugs or radiation to kill rapidly growing cells – like those found in tumours - but also damage many of the bodies healthy tissues in the process. It's the damage to the healthy tissues that produces many of the severe side effects including hair loss, nausea, abdominal pain and loss of appetite. But the new agent, which is called Bexxar, consists of a radioactive substance that can kill cells, linked to an antibody that hunts down and sticks on to cancer cells, but not healthy cells, delivering the toxic dose of radioactivity only to where it is needed – in the tumour – and nowhere else. So far the new agent has been tested on patients for whom traditional chemotherapy has stopped working and for whom the prognosis would be poor. But for these patients, clinical trials found 70 percent of patients responded to Bexxar and 20 percent to 30 percent achieved a complete remission, where no signs of lymphoma are present in imaging tests or biopsy. Mark Kaminski, who helped to develop the new agent, said "this offers a new option and provides hope for patients who had run out of options.


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