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Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than ' million visitors each month.


WHO International Clinical Trials Registry Platform
The World Health Organization (WHO) has created a new Web site to help researchers, doctors and patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!




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Week Ending FRIDAY November 20, 2009---------------------News Archive
The Visible Embryo maintains a searchable database of artcles published since 2007

Boosting Learning and Memory in Down Syndrome

Boosting the level of a brain chemical reverses learning impairments in a mouse model of Down syndrome, researchers report. The work adds to emerging evidence that cognition-enhancing drugs may one day help humans with Down syndrome lead more independent lives.

Down syndrome is the most common cause of mental retardation, affecting approximately one in 800 babies at birth. People with the disorder have an extra copy of chromosome 21, giving them additional copies of hundreds of genes. This somehow alters brain development and causes mild to severe learning disabilities.

To investigate what goes wrong in the brain of someone who has Down syndrome, researchers led by neurobiologist Ahmad Salehi of Stanford University in Palo Alto, California, turned to a genetically modified strain of mice that has three copies of more than 100 of the genes found on human chromosome 21. These so-called Ts65Dn mice exhibit learning and memory deficiencies and other symptoms of Down syndrome. When Salehi and colleagues examined the brains of Ts65Dn mice under a microscope, they discovered degeneration in a region near the base of the brain called the locus coeruleus. This region contains neurons that extend armlike axons all the way to the hippocampus, a key memory center tucked deep inside the temporal lobes. These neurons release the neurotransmitter norepinephrine, which promotes learning and memory in the hippocampus.


Reasoning that the loss of the locus coeruleus neurons might undermine learning and memory by causing a deficit of norepinephrine in the hippocampus, the researchers gave Ts65Dn mice drugs that boost levels of this neurotransmitter throughout the brain. A few hours after delivering the drugs, the researchers tested how well mice were able to learn and remember an enclosure in which they'd received a mild electric shock. Without the drug, Ts65Dn mice performed miserably on this memory test, but with the drug they were as good as normal mice, the researchers report today in Science Translational Medicine.

Because this type of learning depends on the hippocampus, the findings suggest that's where the norepinephrine boost exerts its beneficial effect, Salehi says. Several drugs that enhance norepinephrine are already approved or are in advanced clinical trials for treating low blood pressure and other disorders in humans, which should make it easier to launch a trial in people with Down syndrome if additional animal studies support that approach, Salehi says.

"It's a very positive development," says Roger Reeves, a geneticist at Johns Hopkins University in Baltimore, Maryland. He notes that other recent rodent studies have suggested that drugs that target the neurotransmitter GABA, among others, may also help improve cognition in Down syndrome. Although some researchers have begun to test such cognitive-enhancing drugs in people with Down syndrome, Reeves says the studies to date have been small and fraught with methodological problems, so he doesn't consider them to be reliable. Even so, he says, "5 years ago I never would have believed we would be looking at this kind of fundamental therapy for Down syndrome."


The Developing Child: Rating Aggressive Behavior

In a study published in an upcoming issue of The Journal of Child Psychology and Psychiatry researchers show that over reactive parenting, such as heavy criticism or yelling as a response to a child’s negative behavior, can produce higher levels of aggression or rule-breaking in a child who is normally introverted, non-benevolent, non-conscientious, or imaginative.

Children who are extraverted, benevolent, conscientious, or not that imaginative by nature are least adversely affected by this parental response.

The research (taken from 586 families) shows that rule-breaking and aggressive behavior is influenced by the inherent personality traits of a child. The study also shows that aggression-related behavior generally decreases as the children grow but on average the rule-breaking behavior does not change, and both genders exhibit these behaviors between the ages six to fifteen. When examining both personality and gender boys and girls are not different affected by parenting methods.

To view the abstract for this article, please click here.

WHO Child Growth Charts