Sep 012008
ISLAMABAD: Gene therapy has the potential to restore hearing in mice, offering hope for humans too, US scientists suggest.An Oregon team discovered gene transfer produced functioning hair cells that are essential for the inner ear to interpret sounds, Nature reports.

In people with normal hearing, cochlear hair cells convert sound into electrical signals, which are ultimately transmitted to the brain.

Once the cells are lost or damaged, they cannot be replaced naturally.

According to the Royal National Institute for Deaf People (RNID), there are about nine million people who are deaf or hard of hearing in the UK.

Most of them have lost their hearing gradually with increasing age, partly due to the loss of hair cells in the cochlea.

Repair and replace

Prolonged exposure to loud noise is another culprit, damaging the hair cells.

John Brigande and his team from Oregon Health and Science University showed, at least in unborn mice, gene therapy can be used to encourage other cells to become hair cells.

Gene therapy uses a harmless virus to insert copies of the key gene into cells which then replicate.

The key gene used by the Oregon team was Atoh1 which is essential for hair cell development.

The cells “treated” with Atoh1 functioned exactly like original hair cells.

“This capability is a crucial first step in defining translational therapies to ameliorate the effects of inner-ear disease in humans,” the researchers said.

Work in humans is still a way off, but the findings point to a way to repair the damaged cochlea without using a mechanical or electrical device.

Currently, people can have a cochlear implant which works by bypassing the damaged cochlear hair cells and stimulating the auditory nerve directly.

An implant cannot restore hearing to normal but it does give the sensation of sounds.

Andy Forge, Professor of Auditory Cell Biology and advisor to Deafness Research UK, said: “Although still a long way from the clinic, the work shows that gene therapy is a potential treatment to combat some forms of congenital deafness.

Activity key to breast cancer patients’ survival: Women who stay active after being diagnosed with breast cancer — and even those who take up exercise for the first time after diagnosis — have a better chance of surviving the disease, a new study shows.

“Anything is better than nothing,” Dr. Melinda L. Irwin of the Yale School of Medicine in New Haven, Connecticut, one of the researchers on the study, told Reuters Health. “We actually observed benefits with just doing a little bit of exercise.”

Dozens of studies over the past two decades have shown that exercising can reduce breast cancer risk by up to 40 percent, while more recent research has found that activity has equal or even greater benefits for survival among women with the disease.

To better understand the timing and amount of physical activity necessary to improve survival, Irwin and her team looked at 933 women who had been diagnosed with breast cancer between 1995 and 1998 and were followed until 2004.

They found that women who got the equivalent of at least two to three hours of brisk walking each week in the year before they were diagnosed with breast cancer were 31 percent less likely to die of the disease than women who were sedentary before their diagnosis.

Two years after diagnosis, the women who did any recreational activity at all had a 64 percent lower risk of dying than women who were inactive at that point, while women who got at least two to three hours of brisk walking in weekly reduced their risk of death by 67 percent.

Women who decreased their physical activity after diagnosis were actually four times more likely to die of breast cancer than those who were sedentary and remained so, Irwin and her colleagues found. But those who had been inactive and started exercising after being diagnosed cut their death risk by 45 percent.

Women undergoing breast cancer treatment should think of exercise as a part of their therapy, Irwin said, and be sure to make the time for it, even just by beginning with a 15-minute walk every other day.

Being active isn’t only beneficial for survival, Irwin said; it may also help with the increased cardiovascular disease risk that may accompany treatment, and will certainly improve women’s quality of life in many ways. “Hopefully this study shows what a major benefit exercise can be,” she said.

 Posted by at 11:41 am

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