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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.


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Pregnancy Timeline by SemestersFemale Reproductive SystemFertilizationThe Appearance of SomitesFirst TrimesterSecond TrimesterThird TrimesterFetal 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 HemispheresEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterDevelopmental Timeline
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July 19, 2012--------News Archive Return to: News Alerts


In this illustration, the long DNA molecule (blue) wraps around HISTONES (green flags) changing the shape of the DNA,and emitting new proteins from the new shape (yellow).

WHO Child Growth Charts

       

How Embryonic Stem Cells Can Become Any Cell

A new understanding of the mechanisms giving embryonic stem cells their plasticity could allow manipulation of es cells in the laboratory to be used for treating degenerative diseases

New research at the Hebrew University of Jerusalem sheds light on pluripotency—the ability of embryonic stem cells to renew themselves indefinitely and to differentiate into all types of mature cells.

Solving this problem - which is a major challenge in modern biology - could expedite the use of embryonic stem cells in cell therapy and regenerative medicine.

If scientists can replicate the mechanisms that make pluripotency possible, they could create cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer's, Parkinson's, diabetes and other degenerative diseases.

In fact, these processes were found by researchers in the lab of Dr. Eran Meshorer, in the Department of Genetics at the Hebrew University's Alexander Silberman Institute of Life Sciences, combine molecular, microscopic and genomic approaches. Meshorer's team is focusing on epigenetic pathways—which cause biological changes without changing the DNA sequence—that are specific to embryonic stem cells.

The specific groundbreaking research was performed by Shai Melcer, a PhD student in the Meshorer lab.


The molecule which is the basis for epigenetic
mechanisms is chromatin.

Chromatin is made up of a cell's DNA
with the addition of structural and regulatory proteins.

In embryonic stem cells,
an "open" chromatin configuration
means chromatin is less condensed.


This allows the molecule to have the flexibility
- or "functional plasticity"-
to turn into any kind of cell.


A distinct pattern of chemical modifiers on the chromatin structural proteins (referred to as acetylation and methylation of histones) enables a looser chromatin configuration in embryonic stem cells. During the early stages of differentiation, this pattern changes to facilitate chromatin compaction.


But even more interestingly, the authors found
that a nuclear lamina protein -
lamin A - is a big part of the secret.

In all differentiated cell types,
lamin A binds compacted domains of chromatin,
anchoring those domains to the cell's nuclear wall.

Lamin A is absent from embryonic stem cells
and this may enable the unanchored,
now more dynamic chromatin,
with in the cell nucleus.


The authors believe that chromatin plasticity is critical to functional plasticity since chromatin is made up of DNA that includes all genes and codes for all proteins in any living cell. Understanding the mechanisms that regulate chromatin function will enable intelligent manipulations of embryonic stem cells in the future.

Dr. Meshorer: "If we can apply this new understanding about the mechanisms that give embryonic stem cells their plasticity, then we can increase or decrease the dynamics of the proteins that bind DNA and thereby increase or decrease the cells' differentiation potential.

This could expedite the use of embryonic stem cells in cell therapy and regenerative medicine, by enabling the creation of cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer's, Parkinson's, diabetes and other degenerative diseases."

The research was funded by grants from the European Union (ERC, Marie Curie), Israel Science Foundation, Ministry of Science, Ministry of Health, The National Institute for Psychobiology, Israel Cancer Research Foundation (ICRF), Abisch-Frenkel Foundation and Human Frontiers Science Program (HFSP).

The research appears in the journal Nature Communications as Melcer et al., Histone modifications and lamin A regulate chromatin protein dynamics in early embryonic stem cell differentiation.

Original article: http://www.eurekalert.org/pub_releases/2012-07/thuo-rim071812.php