Wednesday, January 28, 2009

Now you CATCH obesity ...spreading fat cells are linked to a virus

Sounds unlikely. Medicalizing a social problem again, I would think

Obesity can be 'caught' from another individual in the same way as a cold, scientists suggest. The condition has been linked to a highly-infectious virus which causes sniffles and sore throats. Spread by dirty hands, the adenovirus apparently attacks tissue and causes fat cells to multiply - leading to massive weight gain. Previous studies have shown that chickens and mice infected with the bug put on weight more quickly than uninfected animals - even when they do not eat more. Now human studies show that almost a third of obese adults carry the virus compared with 11 per cent of lean men and women.

Professor Nikhil Dhurandhar, who led the research, said the bug continues to add weight gain long after those infected recover from their cough or cold. He told BBC2's Horizon programme, to be shown at 9pm tonight: 'This virus goes to the lungs and spreads through the body. 'It goes to various organs and tissues such as the liver, kidney, brain and fat tissue. 'When this virus goes to fat tissue it replicates, making more copies of itself and in the process increases the number of new fat cells [why and how?], which may explain why the fat tissue expands and why people get fat when they are infected with this virus.'

The professor, from Pennington Biomedical Research Centre in Louisiana, said victims could remain infectious for up to three months. 'But people could be fat for reasons other than viral infections so it's really pointless to try to avoid fat people to avoid infection,' he said.

Learning more about adenovirus's role in weight gain could speed the development of an antiobesity vaccine, or drugs to tackle the condition. British obesity experts, however, dismissed evidence of a link with adenovirus as 'sparse'. Tam Fry, of the Child Growth Foundation, said: 'You are much more likely to pick up the flu than obesity. In general, obesity is down to eating more than you need and not exercising as much as you should.'

Dr Ian Campbell, a GP and medical director of the charity Weight Concern, said: 'A virus will never be the reason for why we have an obesity epidemic. 'There are far too many other factors, starting with our calorie intake exceeding our expenditure, and that's because we live such sedentary lives. 'Our dietary habits have changed beyond belief and I don't believe that's the effect of a viral infection - it is the fault of the commercial expansion of companies making unhealthy foods.'

Professor Colin Waine, past president of the National Obesity Forum, said: 'What we don't want to lose sight of is that if people can lose 5 to 10 per cent of their weight, the benefits on health are disproportionately good.'

Tonight's documentary also features research which could explain why dieters feel permanently hungry and often regain the weight they have lost. Dr Rudy Leibel, from Columbia University in New York, said individuals have a ' natural body weight' to which they are programmed to return after dieting. So naturally overweight people who diet will always suffer hunger pangs, even if they become lean and healthy. 'Individuals have a biology which determines how tall or short they will be and how skinny or fat they will be, and wishing it one way or the other really cannot change it that much.'


IVF advance promises leap in success rates

Success rates for IVF could be improved dramatically by a pioneering new IVF test that promises to help thousands of infertile couples to start a family. The new procedure, developed by British scientists, selects the most viable eggs for use in fertility treatment, by screening out those with genetic defects that would cause them to fail. A British woman was today announced as the first in the world to have benefited from the test.

The technique, developed by researchers at Care Fertility in Nottingham, has enabled the unnamed 41-year-old woman to conceive after 13 failed cycles of IVF treatment. She is due to give birth in two months time. The screening procedure could transform the prospects of motherhood for older infertile women and those with a history of miscarriage or IVF failure. It should also improve success rates among younger patients with a good chance of conceiving by IVF. While previous egg and embryo quality tests have been licensed only for women with a poor prognosis, the new one has been approved for any patient.

Simon Fishel, managing director of Care Fertility, who led the development team, estimates that as many as half of all couples having fertility treatment could benefit from the technique, known as Array Comparative Genomic Hybridisation (Array CGH). "IVF success rates are around 30 per cent, and reach 40 per cent only in the best clinics, which means at least 60 per cent of cycles still fail," he said. "One of the holy grails is to get to one embryo, one baby, but the great stumbling block is that only 25 to 30 per cent of eggs are actually viable. By being able to select the normal ones, we should have an impact on success rates. How great that might be we don't yet know."

Array CGH would be especially useful when only a single embryo is transferred to the womb, to prevent the multiple pregnancies that are by far the greatest hazard of IVF, Dr Fishel said. The Human Fertilisation and Embryology Authority (HFEA) is seeking to reduce IVF twin and triplet births from one in four to one in ten, which will require many more patients than at present to have a single embryo transfer. "Converting IVF to single embryos is going to hit some patients very hard in terms of success rates, but if we can select those eggs and embryos with the highest chance of being chromosomally normal, I am hopeful we can mitigate that," Dr Fishel said. "I think this technology will lead towards this goal."

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