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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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Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
Click weeks 0 - 40 and follow fetal growth
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April 29, 2011--------News Archive

Catching Autism At The 1-Year Well-Baby Check-Up
A novel strategy developed by autism researchers at the University of California, San Diego, shows promise as a simple way to detect cases of Autism Syndrome.

A New Wrinkle In The Genetic Code
Long ago a mouse was created that is just now teaching us that mutations in the proteins produced from ribosomes can lead to unexpected birth defects.


April 28, 2011--------News Archive

Tired Neurons Nod Off in Sleep-Deprived Rats
The more rats are sleep-deprived, the more neurons take catnaps. Though the animals are awake and active, neurons in the cortex, are briefly falling asleep.

Obese Adolescents Lacking Vitamin D
Vitamin D status is significantly associated with muscle power/force; a deficiency may interfere with the obese adolescent's ability to increase physical activity.


April 27, 2011--------News Archive

Men and Women Respond Differently to PTSD
Men and women had starkly different immune system responses to chronic post-traumatic stress disorder. Men show no response, women show a strong one.

Motor Protein May Offer Promise In Ovarian Cancer
A regulatory motor protein can block ovarian tumor growth, leading to cancer cell death and new therapies to treat the disease.


April 26, 2011--------News Archive

Protein Levels Could Signal Childhood Diabetes
Decreasing blood levels of a protein that helps control inflammation may be a red flag that could help children avoid type 1 diabetes.

Best Treatment For Gestational Tumors
A clinical trial has sifted out the most effective chemotherapy regimen for quick-growing but highly curable cancers arising from the placentas of pregnant women.


April 25, 2011--------News Archive

Frog Embryos Teach Us About Heart Development
Thanks to new research at the University of Pennsylvania, there is new insight into the processes that regulate the formation of the heart.

Brain Cells Offer Insight on How Cancer Spreads
The mechanism regulating embryonic development in plants displays similarities to a signalling pathway in embryonic stem cells in mammals.

WHO Child Growth Charts

Discovered in the 1940s, the "tail short" mouse has a kinky tail and an extra set of ribs in its neck.

Call it a mystery with a stubby tail: an odd-looking mouse discovered through a U.S. government breeding program in the 1940s that had a short, kinky tail and an extra set of ribs in its neck – and nobody knew why.

A team of scientists led by researchers at the University of California, San Francisco has now spilled the genetic secrets of this mutant rodent. In doing so, they may have uncovered a new wrinkle in the genetic code – an entirely unrecognized way our bodies regulate how genes are expressed in different tissues throughout life.

This discovery has broad implications for how we think about developmental biology, and it may explain the origins of numerous developmental diseases. It also may help suggest new ways of treating certain types of cancer, many of which may be linked, at least in part, to problems in how the body regulates gene expression.

“The ultimate outcome of gene expression is the production of proteins,” said UCSF Faculty Fellow Maria Barna, PhD, who led the research. “Our study suggests that there is a new way of controlling which types of proteins will be produced in which types of cells.”

As described in this week’s issue of the journal Cell, the research identified a molecular machine called the ribosome as the factor that exerts this new control over gene expression. Though well known to scientists as a key component of living cells, the ribosome was never thought to play a regulatory role.

The “tail short” mutant mouse first appeared in 1946 at the National Cancer Institute in Bethesda, MD, where several were discovered among a litter of offspring born to a highly inbred strain of mice raised in a breeding program. They all had very unusual skeletal features: short, stubby tails and an extra set of ribs in their neck vertebrae.

Doctors recognized the uniqueness and potential importance of the mouse immediately. It wasn’t just that the skeleton was malformed – it seemed to be misplaced. The neck vertebrae had ribs and resembled vertebrae lower in the spine. It was as if the body plan of this mouse had been incorrectly mixed up in early development, though it was beyond the ability of scientists in those days to determine why.

Through the decades, the mouse remained a curiosity of sorts. Its progeny were carefully bred year after year, but decades passed before anyone could determine which genes were responsible for its unusual features.

Finally, a few years ago, Barna and her colleagues, became interested in the mouse, and she worked with scientists at the National Institute of Genetics in Japan to identify the exact mutations that cause the malformations. A developmental biologist herself, Barna suspected that the mouse's peculiar skeletal structures suggested some sort of anomalous "patterning" in early development, where one part of the body forms incorrectly in the shape of a different part. What they found, said Barna, was a complete surprise.

The mutations turned out to be in the ribosome, a massive molecular machine that makes proteins and are common to all forms of life. They can be found in every cell in every tissue of the human body, and scientists believe that similar versions have been inside every cell of every creature that ever lived – whether cat, carp, cholera or Caesar.

The ribosome is so common because it plays a central role in biology by making proteins that do everything from building the body’s tissues to carrying out crucial biological functions, like breaking down food in the gut and encoding memories in the brain. Despite its importance, scientists had always assumed that the ribosome was something of an automaton – a machine that simply took instructions from a creature's genetic code and spit out proteins. Mutations in the tail short mouse, however, showed otherwise.

These mutations turned out to delete a protein called Rpl38, one of 79 proteins that make up the mouse ribosome. Without Rpl38, the ribosome in the tail short mouse still worked, but it lost the ability to control which proteins it expressed – an ability scientists never thought the ribosome had in the first place. Moreover, the effect was not generalized throughout the body of the mouse, but specific only to certain tissues.

In early fetal development, the loss of Rpl38 caused certain parts of the backbone to grow and develop as if they were elsewhere in the spine – thus the extra ribs in the neck. Mutations in the proteins of human ribosomes can also lead to unexpected tissue-specific congenital birth defects including malformations of the spine, face, limbs, heart and other organs. The reasons why have been a mystery, but the explanation may be that the ribosome plays a fundamental regulatory role in embryonic development.

“It dictates where and when the final outcomes of gene products are expressed,” said Barna. “Therefore the genetic code has a previously unrecognized set of instructions that are carried out by the ribosome to control cell behavior. For example, whether or not a vertebrate has a pair of ribs associated with it.”

The work also suggests that ribosomes could act differently in different tissues in the body, adding an entirely new layer of complexity to the already complex program by which the genetic code is expressed in living creatures.

The article, “Ribosome-Mediated Specificity in Hox mRNA Translation and Vertebrate Tissue Patterning” by Nadya Kondrashov, Aya Pusic, Craig Stumpf, Kunihiko Shimizu, Andrew C. Hsieh, Shifeng Xue, Junko Ishijima, Toshihiko Shiroishi, and Maria Barna appears in the April 29, 2011 issue of the journal Cell. This work was funded by the Program for Breakthrough Biomedical Research, UCSF, the March of Dimes, a Basil O’Connor Scholar Research Award, and MEXT, Japan.

Original article: http://www.ucsf.edu/news/2011/04/9793/mutant-mouse-reveals-new-wrinkle-genetic-code-say-ucsf-scientists