Scientists have found that a gene named Prox1 is a key player in normal development of a brain structure crucial for learning and memory and remains active throughout life, nurturing the cells vital for making new memories. The study by St. Jude Children's Research Hospital focused on a small region of the hippocampus known as the dentate gyrus, a brain structure needed for memory and learning that is home to the subgranular zone where the neural stem cells destined to become granule cells are housed.
The dentate gyrus is one of two regions of the adult brain where neural stem cells continue to produce the precursor cells that ultimately differentiate into neurons.
Although investigators knew Prox1 was expressed during development of the dentate gyrus, this is the first report detailing the gene's function in this region of the brain. Prox1 is a transcription factor that functions like an on-off switch for genes.
Researchers showed that by removing Prox1 at different stages of mouse development, the dentate gyrus fails to develop properly. Investigators also demonstrated that Prox1 remains important throughout mammalian life to ensure production of new granule cells, which are needed to form new memories.
The findings raise the possibility that subtle mutations in Prox1 might be linked to memory and learning problems, said the paper's senior author Guillermo Oliver, member of the St. Jude Department of Genetics.
"The more we understand about how signaling pathways work in the brain, the more we will eventually be able to manipulate the system to promote or block the differentiation process," he said.
Friday, September 10, 2010
Thursday, September 9, 2010
More evidence ties smoking, decreased fertility
If you're looking to make a baby, you might want to put out your cigarette before getting down to business: There's now more evidence linking smoking with decreased fertility in men and women — and their offspring.
A new study shows smoking by women during early pregnancy reduces the number of germ cells in the embryo. Germ cells later develop into eggs or sperm, so this reduction has the potential to reduce the baby's future fertility.
And men who smoke develop an imbalance in their levels of a protein, called protamine, that is vital to sperm fertility, another new study suggests.
The findings fall in line with past studies on the effects of smoking and secondhand smoke on fertility, researchers say. Research from the University of Buffalo in 2005 showed male smokers' sperm had a more difficult time binding to an egg than non-smokers' sperm. And research from the University of Rochester in 2008 showed that women who had been exposed to secondhand smoke as children or young adults were more likely to have trouble getting pregnant.
Germ cell study researcher Claus Yding Andersen of the University Hospital of Copenhagen said more research is needed to demonstrate whether the reductions in germ cells are permanent or are compensated for later in the pregnancy. Either way, he told MyHealthNewsDaily, "If women plan to get pregnant, this should be an incentive to quit smoking."
For male embryos, the number of germ cells was reduced by more than half when their mothers smoked during the first trimester of pregnancy, compared with mothers who didn't smoke at all, said Andersen. For all embryos, the reduction in germ cells averaged 41 percent.
And the more a mother smoked, the greater the reduction in the germ cells of her embryo, he said.
A new study shows smoking by women during early pregnancy reduces the number of germ cells in the embryo. Germ cells later develop into eggs or sperm, so this reduction has the potential to reduce the baby's future fertility.
And men who smoke develop an imbalance in their levels of a protein, called protamine, that is vital to sperm fertility, another new study suggests.
The findings fall in line with past studies on the effects of smoking and secondhand smoke on fertility, researchers say. Research from the University of Buffalo in 2005 showed male smokers' sperm had a more difficult time binding to an egg than non-smokers' sperm. And research from the University of Rochester in 2008 showed that women who had been exposed to secondhand smoke as children or young adults were more likely to have trouble getting pregnant.
Germ cell study researcher Claus Yding Andersen of the University Hospital of Copenhagen said more research is needed to demonstrate whether the reductions in germ cells are permanent or are compensated for later in the pregnancy. Either way, he told MyHealthNewsDaily, "If women plan to get pregnant, this should be an incentive to quit smoking."
For male embryos, the number of germ cells was reduced by more than half when their mothers smoked during the first trimester of pregnancy, compared with mothers who didn't smoke at all, said Andersen. For all embryos, the reduction in germ cells averaged 41 percent.
And the more a mother smoked, the greater the reduction in the germ cells of her embryo, he said.
Wednesday, September 8, 2010
NHS buys porn for sperm donors
The hard-up NHS is blowing taxpayers' cash on porn for sperm donors, a report reveals today.
A health think-tank discovered one in three hospitals with fertility services lays on dirty mags. Some also offer blue movies.
Last night the smut was slammed as an affront to the three-quarters of NHS staff who are women - many of whom fear for their jobs. Seventeen hospitals admitted buying in porn when contacted by the think-tank 2020health.org, which campaigns against NHS waste.
Most top-shelf mags were purchased from newsagents.
But two hospitals confessed they bought porn direct from publishers.
Others said stashes were donated by staff, patients and visitors. One was given material by a top consultant.
The think-tank's director Julia Manning said: "We know of no government authorisation that sanctioned this.
"The reality of porn today is that it increasingly uses younger girls and is more violent and extreme. Seventy-seven per cent of the NHS workforce is female and they should never have to work in an environment that endorses pornography."
She pointed out that only 33 out of 92 hospitals in the investigation used porn as a helping hand for donors.
The Sun revealed earlier this year how Liverpool Women's NHS Foundation Trust splashed out £7,500 on computers, flat-screen TVs, a DVD unit and blue movies for hospital sperm donors.
Tuesday, September 7, 2010
Blood disorder cured – a first for gene therapy
A 21-YEAR-OLD Frenchman is the first person in the world to be cured of the blood disorder beta-thalassaemia through gene therapy. But there is some confusion over what made the treatment work.
Before gene therapy he needed monthly blood transfusions to provide him with beta-globin, a key component of the haemoglobin molecule that carries oxygen around the body. He has now been transfusion-free for over two years.
Philippe Leboulch of the University of Paris, France, and Harvard Medical School in Boston, infected stem cells from the man's bone marrow with a harmless virus, which transferred perfect copies of the beta-globin gene into the DNA of the extracted cells.
Returned to the patient, these cells now contribute about a third of his beta-globin, with his body producing the rest. Although the treatment had the desired effect, the proliferation of the altered cells could be down to the activation of a different gene, HMGA2, switched on by accident during the DNA transfer.
One worry throughout the history of gene therapy is that viruses transferring beneficial genes will accidentally activate other genes that could trigger cancer. This happened in four French boys treated for the immune deficiency, X-SCID, who developed leukaemia. One died and the others recovered after treatment.
"We must be very cautious, but the signs are that the impact of the HMGA2 gene will be benign," says Leboulch.
After more detailed analysis, the team found other cells producing beta-globin that do not have the HMGA2 gene switched on. Leboulch concludes that it is unlikely the HMGA2 gene by itself is responsible for the survival of the beta-globin-producing cells.
Before gene therapy he needed monthly blood transfusions to provide him with beta-globin, a key component of the haemoglobin molecule that carries oxygen around the body. He has now been transfusion-free for over two years.
Philippe Leboulch of the University of Paris, France, and Harvard Medical School in Boston, infected stem cells from the man's bone marrow with a harmless virus, which transferred perfect copies of the beta-globin gene into the DNA of the extracted cells.
Returned to the patient, these cells now contribute about a third of his beta-globin, with his body producing the rest. Although the treatment had the desired effect, the proliferation of the altered cells could be down to the activation of a different gene, HMGA2, switched on by accident during the DNA transfer.
One worry throughout the history of gene therapy is that viruses transferring beneficial genes will accidentally activate other genes that could trigger cancer. This happened in four French boys treated for the immune deficiency, X-SCID, who developed leukaemia. One died and the others recovered after treatment.
"We must be very cautious, but the signs are that the impact of the HMGA2 gene will be benign," says Leboulch.
After more detailed analysis, the team found other cells producing beta-globin that do not have the HMGA2 gene switched on. Leboulch concludes that it is unlikely the HMGA2 gene by itself is responsible for the survival of the beta-globin-producing cells.
Monday, September 6, 2010
Doctor sued over allegedly mixing up sperm samples
An Ottawa fertility doctor is being sued for allegedly mixing up sperm samples and inseminating the wrong one into two of his patients.
Trudy Moore launched a civil lawsuit against Bernard Norman Barwin last year after she learned that her daughter, Samantha, is not a genetic match to her husband, Matthew Guest, the statement of claim said.
Recently, another woman also came forward and filed a statement of claim against Dr. Barwin. Jacqueline Slinn found out in April that her five-year-old daughter Bridget is not a genetic match to her intended sperm donor, the statement said.
Both women are seeking more than $1-million in damages and an order requiring Dr. Barwin to identify their children’s father. No mediation or court dates have been set.
“We are currently investigating how widespread this problem may be,” said Pam MacEachern, lawyer for Ms. Moore and Ms. Slinn. “We would be pleased to speak with anyone else who has had a similar experience.”
In a statement of defence filed by Dr. Barwin in response to Ms. Moore’s lawsuit, he denied any allegations of negligent care or wrongdoing. The claim states that all medical care and treatments provided were carried out in a careful, competent and diligent manner and in accordance with the applicable standard of care.
Dr. Barwin and his lawyer could not be reached for comment.
According to Ms. Slinn’s statement of claim, Bridget’s father was supposed to be sperm donor number 3168. After Ms. Slinn learned that her daughter did not match him, she tested the vial of sperm that was used to inseminate her from Dr. Barwin’s clinic. The results showed that the vial from his clinic was contaminated with unidentified male DNA, the statement said.
In an interview, Ms. Slinn said she had no idea that there was even a risk of that kind of mistake when she went into her procedure nearly six years ago. “I carried on merrily thinking it was 3168,” she said.
Ms. Moore’s story is more complex. Now two-year-old Samantha was conceived through a surrogate, and the man she calls “daddy” is supposed to be her biological father. But due to the mix-up at Dr. Barwin’s clinic, her parents still don’t know who Samantha’s biological father is, the statement said.
“From Samantha’s perspective, we don’t know her medical history,” Ms. Moore said in an interview. “She may never care, but if she does I can’t fix that. As a parent we want the best for our children, we want to protect our children, we want to fix things for our children. This is something I will never be able to give her.”
DNA tests have ruled out the surrogate’s husband and other potential sperm donors.
Dr. Barwin is a member in good standing with the College of Physicians and Surgeons and is certified to practice as a general physician. He specializes in reproduction and has nearly 30 years of experience. In 1997, he received the Order of Canada for his contributions to women’s reproductive health.
Trudy Moore launched a civil lawsuit against Bernard Norman Barwin last year after she learned that her daughter, Samantha, is not a genetic match to her husband, Matthew Guest, the statement of claim said.
Recently, another woman also came forward and filed a statement of claim against Dr. Barwin. Jacqueline Slinn found out in April that her five-year-old daughter Bridget is not a genetic match to her intended sperm donor, the statement said.
Both women are seeking more than $1-million in damages and an order requiring Dr. Barwin to identify their children’s father. No mediation or court dates have been set.
“We are currently investigating how widespread this problem may be,” said Pam MacEachern, lawyer for Ms. Moore and Ms. Slinn. “We would be pleased to speak with anyone else who has had a similar experience.”
In a statement of defence filed by Dr. Barwin in response to Ms. Moore’s lawsuit, he denied any allegations of negligent care or wrongdoing. The claim states that all medical care and treatments provided were carried out in a careful, competent and diligent manner and in accordance with the applicable standard of care.
Dr. Barwin and his lawyer could not be reached for comment.
According to Ms. Slinn’s statement of claim, Bridget’s father was supposed to be sperm donor number 3168. After Ms. Slinn learned that her daughter did not match him, she tested the vial of sperm that was used to inseminate her from Dr. Barwin’s clinic. The results showed that the vial from his clinic was contaminated with unidentified male DNA, the statement said.
In an interview, Ms. Slinn said she had no idea that there was even a risk of that kind of mistake when she went into her procedure nearly six years ago. “I carried on merrily thinking it was 3168,” she said.
Ms. Moore’s story is more complex. Now two-year-old Samantha was conceived through a surrogate, and the man she calls “daddy” is supposed to be her biological father. But due to the mix-up at Dr. Barwin’s clinic, her parents still don’t know who Samantha’s biological father is, the statement said.
“From Samantha’s perspective, we don’t know her medical history,” Ms. Moore said in an interview. “She may never care, but if she does I can’t fix that. As a parent we want the best for our children, we want to protect our children, we want to fix things for our children. This is something I will never be able to give her.”
DNA tests have ruled out the surrogate’s husband and other potential sperm donors.
Dr. Barwin is a member in good standing with the College of Physicians and Surgeons and is certified to practice as a general physician. He specializes in reproduction and has nearly 30 years of experience. In 1997, he received the Order of Canada for his contributions to women’s reproductive health.
Sunday, September 5, 2010
Hull IVF unit innovation is to be rolled out across UK
Technology used in fertility treatment which has been adopted by Hull's IVF unit is being rolled out across the rest of the UK.
The unit has also been nominated for a national award for use of the technology.
The technology lessens the risk of a mix up when the sperm and egg are put together by activating an alarm.
It was designed following highly publicised adverse incidents across the UK.
The unit said IVF mix-ups were rare but in recent years there had been four "highly publicised serious adverse incidents" in UK clinics.
It said two involved incorrect identification of sperm samples and resulted in the live birth of twins.
As a consequence the Human Fertility and Embryology Authority (HFEA) - the UK's independent regulator overseeing the use of gametes and embryos in fertility treatment and research - introduced a requirement for all movement of sperm, eggs and embryos during any clinical or laboratory process to be witnessed to prevent mismatches.
The technology works through a tracking process ensuring that the resulting embryo is transferred to the correct patient.
If at any time the wrong samples are introduced, the system warns the laboratory personnel both visually and audibly.
A spokeswoman for the unit said: "The system provides an invaluable reassurance for patient's nurses and embryologists alike."
The clinic, which is based at Hull Royal Infirmary, has been nominated for the Best Use of Technology category at the the Independent Health Care Awards. The winners will be announced on 14 September.
According to the Hull IVF Unit 37,000 women undergo fertility treatments in the UK every year.
The unit has also been nominated for a national award for use of the technology.
The technology lessens the risk of a mix up when the sperm and egg are put together by activating an alarm.
It was designed following highly publicised adverse incidents across the UK.
The unit said IVF mix-ups were rare but in recent years there had been four "highly publicised serious adverse incidents" in UK clinics.
It said two involved incorrect identification of sperm samples and resulted in the live birth of twins.
As a consequence the Human Fertility and Embryology Authority (HFEA) - the UK's independent regulator overseeing the use of gametes and embryos in fertility treatment and research - introduced a requirement for all movement of sperm, eggs and embryos during any clinical or laboratory process to be witnessed to prevent mismatches.
The technology works through a tracking process ensuring that the resulting embryo is transferred to the correct patient.
If at any time the wrong samples are introduced, the system warns the laboratory personnel both visually and audibly.
A spokeswoman for the unit said: "The system provides an invaluable reassurance for patient's nurses and embryologists alike."
The clinic, which is based at Hull Royal Infirmary, has been nominated for the Best Use of Technology category at the the Independent Health Care Awards. The winners will be announced on 14 September.
According to the Hull IVF Unit 37,000 women undergo fertility treatments in the UK every year.
Saturday, September 4, 2010
Chemical patterns on DNA mark out obesity genes
Your genes play a big part in determining your body shape, but that role may not have been set in stone when your parents' egg and sperm got together. It now looks like chemical changes that happen to genes over a person's lifetime may influence how fat they become, without altering their inherited DNA sequences.
This is the first time that prolonged chemical changes to genes during life have been implicated in obesity and body weight.
The findings add to the mounting evidence that it's not only genes that dictate important bodily traits – environmental cues and conditions may also affect such traits by altering gene activity. These "epigenetic" changes influence whether genes are on or off, but do not change the DNA sequence.
The latest findings relate to epigenetic changes which involve methylation, the process by which the addition of chemicals called methyl groups to DNA can turn genes on or off, or moderate a gene's activity by changing the way it is read.
Icelandic obesity
A team led by Andrew Feinberg of Johns Hopkins University School of Medicine in Baltimore, Maryland, and Daniele Fallin of the Johns Hopkins Bloomberg School of Public Health, also in Baltimore, mapped methylation in the DNA of 74 adults with a range of body types, looking for patterns that seemed likely to have been prolonged and set early in life, or even in the womb.
To do this, they first screened the volunteers' DNA in 1991, and picked out 227 regions with methylation patterns that varied between the individual members of the group by an unusually large amount. They then screened the same people in 2002 to distinguish which methylation patterns had not changed over the 11 years, reasoning that the variation in these patterns must have occurred early in life, then become fixed, having a persistent effect on traits such as body weight or intelligence.
Of the 227 methylated sites, 119 were found to be the same in 2002 as they had been 11 years earlier. Feinberg and Fallin then matched these groups to the body type of the individual. They found 13 methylated genes that were more likely to be present in the participants who were overweight or obese.
These chemical changes could have arisen in response to environmental conditions, such as the childhood diet of the individual or even of their mother during pregnancy.
"We don't know yet the degree to which genes and environment add up to give these stable methylation changes, but we believe both are important," says Feinberg.
Usual suspects
The 13 methylated genes include those that make metalloproteinase enzymes, which have already been implicated in obesity through studies on mice. Another, called PRKG1, plays a role when insects and nematodes forage for food.
The researchers caution that it is not yet possible to say whether the methylation changes are a result of environment influence, perhaps in the diet, or whether they are ultimately genetic because they are orchestrated by other genes.
But if specific methylated genes linked with obesity can be identified, they may provide new ways to screen people for risk of becoming overweight or obese. "The results do suggest the importance of including epigenetic analysis with genetic analysis in personalised medicine research to predict risk," says Feinberg.
"Relationships between epigenetic markers such as methylation patterns and particular disease or body states are hard to establish with confidence," says Bryan Turner, a geneticist at the University of Birmingham, UK.
This is the first time that prolonged chemical changes to genes during life have been implicated in obesity and body weight.
The findings add to the mounting evidence that it's not only genes that dictate important bodily traits – environmental cues and conditions may also affect such traits by altering gene activity. These "epigenetic" changes influence whether genes are on or off, but do not change the DNA sequence.
The latest findings relate to epigenetic changes which involve methylation, the process by which the addition of chemicals called methyl groups to DNA can turn genes on or off, or moderate a gene's activity by changing the way it is read.
Icelandic obesity
A team led by Andrew Feinberg of Johns Hopkins University School of Medicine in Baltimore, Maryland, and Daniele Fallin of the Johns Hopkins Bloomberg School of Public Health, also in Baltimore, mapped methylation in the DNA of 74 adults with a range of body types, looking for patterns that seemed likely to have been prolonged and set early in life, or even in the womb.
To do this, they first screened the volunteers' DNA in 1991, and picked out 227 regions with methylation patterns that varied between the individual members of the group by an unusually large amount. They then screened the same people in 2002 to distinguish which methylation patterns had not changed over the 11 years, reasoning that the variation in these patterns must have occurred early in life, then become fixed, having a persistent effect on traits such as body weight or intelligence.
Of the 227 methylated sites, 119 were found to be the same in 2002 as they had been 11 years earlier. Feinberg and Fallin then matched these groups to the body type of the individual. They found 13 methylated genes that were more likely to be present in the participants who were overweight or obese.
These chemical changes could have arisen in response to environmental conditions, such as the childhood diet of the individual or even of their mother during pregnancy.
"We don't know yet the degree to which genes and environment add up to give these stable methylation changes, but we believe both are important," says Feinberg.
Usual suspects
The 13 methylated genes include those that make metalloproteinase enzymes, which have already been implicated in obesity through studies on mice. Another, called PRKG1, plays a role when insects and nematodes forage for food.
The researchers caution that it is not yet possible to say whether the methylation changes are a result of environment influence, perhaps in the diet, or whether they are ultimately genetic because they are orchestrated by other genes.
But if specific methylated genes linked with obesity can be identified, they may provide new ways to screen people for risk of becoming overweight or obese. "The results do suggest the importance of including epigenetic analysis with genetic analysis in personalised medicine research to predict risk," says Feinberg.
"Relationships between epigenetic markers such as methylation patterns and particular disease or body states are hard to establish with confidence," says Bryan Turner, a geneticist at the University of Birmingham, UK.
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