Saturday, February 6, 2010
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Thursday, February 4, 2010
Wednesday, February 3, 2010
Monday, February 1, 2010
Saturday, January 30, 2010
Like babies, embryos like to be rocked, too
Rocking growing embryos during IVF (in vitro fertilisation) could improve pregnancy rates among women undergoing the procedure, and decrease its risks. Scientists at the University of Michigan, US, have built a device which mimics the movement felt by embryos on their way to the uterus. When they used this during IVF with mouse embryos, they found pregnancy rates were 22 per cent higher compared to those grown statically. The research was published online in the journal Human Reproduction and was funded by the National Institutes of Health, the US Department of Agriculture, the Michigan Economic Development Corporation, the US Army Research Laboratory and the Coulter Foundation.
'By making the cells feel more at home, we get better cells, which is key to having better infertility treatment', said Shu Takayama, an associate professor in the Department of Biomedical Engineering and in macromolecular science and engineering. The rocking movement in the device is created by pulsing Braille pins, sitting underneath a thimble-sized funnel holding the embryos. The pins stimulate a flow of fluid through channels in the bottom of the funnel, copying the currents created by cilia - hair-like projections inside the body - and muscles. In the body these motions help to push fertilised eggs to the uterus and flush out waste products.
'One of our goals for years now has been to modify how we grow embryos in the lab to be more like how they grow in the human body, because we know that the human body grows them most efficiently', commented Gary Smith, co-author of the paper and associate professor in the Department of Biomedical Engineering and in macromolecular science and engineering. Presently in IVF, eggs are fertilized with sperm and left to grow for several days in a culture dish that remains still.
If similar results are found in humans, it could lead to reduced multiple pregnancies from the IVF process, its biggest risk. Professor Smith emphasised: 'We're making healthier embryos, which not only can improve pregnancy rates, but also could allow us to transfer fewer embryos per cycle and reduce the incidence of twins and triplets'. In the UK, the Human Fertilisation and Embryology Authority (HFEA) is currently campaigning to reduce multiple births, and the government wants to cut them from one in four to one in ten in IVF by 2012. Trials on humans are already underway, through the company Professor Takayama and Professor Smith founded, Incept Biosystems.
In the US, IVF currently costs around $15,000 per cycle and is often not covered by insurance. It has a success rate of about 35 per cent. 'If we could increase that, even just to 45 per cent, that's significant', said Professor Smith.
'By making the cells feel more at home, we get better cells, which is key to having better infertility treatment', said Shu Takayama, an associate professor in the Department of Biomedical Engineering and in macromolecular science and engineering. The rocking movement in the device is created by pulsing Braille pins, sitting underneath a thimble-sized funnel holding the embryos. The pins stimulate a flow of fluid through channels in the bottom of the funnel, copying the currents created by cilia - hair-like projections inside the body - and muscles. In the body these motions help to push fertilised eggs to the uterus and flush out waste products.
'One of our goals for years now has been to modify how we grow embryos in the lab to be more like how they grow in the human body, because we know that the human body grows them most efficiently', commented Gary Smith, co-author of the paper and associate professor in the Department of Biomedical Engineering and in macromolecular science and engineering. Presently in IVF, eggs are fertilized with sperm and left to grow for several days in a culture dish that remains still.
If similar results are found in humans, it could lead to reduced multiple pregnancies from the IVF process, its biggest risk. Professor Smith emphasised: 'We're making healthier embryos, which not only can improve pregnancy rates, but also could allow us to transfer fewer embryos per cycle and reduce the incidence of twins and triplets'. In the UK, the Human Fertilisation and Embryology Authority (HFEA) is currently campaigning to reduce multiple births, and the government wants to cut them from one in four to one in ten in IVF by 2012. Trials on humans are already underway, through the company Professor Takayama and Professor Smith founded, Incept Biosystems.
In the US, IVF currently costs around $15,000 per cycle and is often not covered by insurance. It has a success rate of about 35 per cent. 'If we could increase that, even just to 45 per cent, that's significant', said Professor Smith.
Friday, January 29, 2010
Chemicals in old furniture can make it harder to get pregnant
Exposure to chemicals found in household objects such as furniture, carpets and electronic equipment increases the time taken to become pregnant, according to a study published online in the journal Environmental Health Perspectives. Professor Kim Harley and colleagues at the University of California, Berkeley (UCB) School of Public Health found that women with a higher blood concentration of polybrominated diphenyl ethers (PBDEs), which have been used as flame retardants since the 1970s, took 'significantly' longer to conceive. It is the first study in humans to examine the association between PBDEs and fertility.
The researchers interviewed 223 pregnant women living in a predominantly Mexican-immigrant, low-income community in northern California. They were asked how long it had taken for them to conceive and blood samples were collected. 'For every tenfold increase in PBDEs in the blood, we saw a 30 per cent to 50 per cent decrease in the odds of becoming pregnant in any given month,' said Professor Harley. The researchers controlled for other factors, such as pesticide exposure, which could potentially affect fertility.
PBDEs were commonly used in the US after the implementation of new fire safety standards four decades ago. Production of certain types of PBDE ceased in 2004, but the chemicals are still found in older products. Previous studies showed that 97 per cent of Americans have detectable levels of these chemicals in their blood, with Californians having higher than average levels due to strict flammability laws. Overall, the levels found in the new study were below the national average.
Household items are considered a major source of PDBE exposure. After leaching out, the chemicals can be inhaled with house dust and stored in the body's fat cells. The chemicals are also found in some foods, such as dairy products and high-fat meat. It is unclear how PDBEs may impair fertility, but one possibility is that they alter the level of the thyroid hormone, which is believed to play an important role in fertility. They have previously been associated with reproductive and hormonal defects in animals.
Industry spokesman John Kyte responded to the study by saying that the findings are limited to PBDEs no longer in use, the environmental levels of which are expected to decline over time. However, Professor Harley maintained that although several PDBEs are banned, exposure is likely to continue for many years. She also described the need for research into newer flame retardants: 'We know less about the health effects of these new chemicals than we do about PBDEs'. This is not the first time that chemicals found in household materials have been linked to reproductive problems. In January 2009 scientists found a link between perfluorinated chemicals (PFCs) and fertility, and in May last year household chemicals were reported to disrupt the sexual development of male fetuses.
The researchers interviewed 223 pregnant women living in a predominantly Mexican-immigrant, low-income community in northern California. They were asked how long it had taken for them to conceive and blood samples were collected. 'For every tenfold increase in PBDEs in the blood, we saw a 30 per cent to 50 per cent decrease in the odds of becoming pregnant in any given month,' said Professor Harley. The researchers controlled for other factors, such as pesticide exposure, which could potentially affect fertility.
PBDEs were commonly used in the US after the implementation of new fire safety standards four decades ago. Production of certain types of PBDE ceased in 2004, but the chemicals are still found in older products. Previous studies showed that 97 per cent of Americans have detectable levels of these chemicals in their blood, with Californians having higher than average levels due to strict flammability laws. Overall, the levels found in the new study were below the national average.
Household items are considered a major source of PDBE exposure. After leaching out, the chemicals can be inhaled with house dust and stored in the body's fat cells. The chemicals are also found in some foods, such as dairy products and high-fat meat. It is unclear how PDBEs may impair fertility, but one possibility is that they alter the level of the thyroid hormone, which is believed to play an important role in fertility. They have previously been associated with reproductive and hormonal defects in animals.
Industry spokesman John Kyte responded to the study by saying that the findings are limited to PBDEs no longer in use, the environmental levels of which are expected to decline over time. However, Professor Harley maintained that although several PDBEs are banned, exposure is likely to continue for many years. She also described the need for research into newer flame retardants: 'We know less about the health effects of these new chemicals than we do about PBDEs'. This is not the first time that chemicals found in household materials have been linked to reproductive problems. In January 2009 scientists found a link between perfluorinated chemicals (PFCs) and fertility, and in May last year household chemicals were reported to disrupt the sexual development of male fetuses.
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