Welcome to The Visible Embryo

 

 

Home-- -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- -Contact
 

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 one million visitors each month.

Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

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!



Home

History

Bibliography

Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System

Contact The Visible Embryo

News Alerts Archive

Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.

 

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 ON weeks 0 - 40 and follow along every 2 weeks of fetal development
Google Search artcles published since 2007
 
 

Home | Pregnancy Timeline | News Alerts |News Archive Oct 31, 2013

 

Human naïve iPS-derived cells (yellow/green) integrating into different
tissues of a developing host mouse embryo (red cells)
Film







WHO Child Growth Charts

 

 

 

New Stem Cells Go Back Further

Scientists isolate new human pluripotent stem cells capable of generating “humanized” mouse models containing human-derived tissues.

One of the obstacles to employing human embryonic stem cells for medical use lies in their very promise: They are born to rapidly differentiate into other cell types.

Until now, scientists have not been able to efficiently keep embryonic stem cells in their pristine stem state. An alternative proposal is to use reprogrammed adult cells called induced pluripotent stem cells (iPS cells). However, although iPS cells can differentiate into many different cell types, they retain signs of “priming” or commitment to specific cell lineages.


A team at the Weizmann Institute of Science has now taken a large step toward removing the 'priming' obstacle from iPS cells.

They have created iPS cells that are completely “reset” to the earliest possible state and can maintain them in that state. Among other things, this research may, in the future, pave the way toward the ability to grow transplant organs to order.


Since they were first created in 2006, iPS cells have been touted as an ethical and practical substitute for embryonic stem cells. They are made by inserting four genes into the genomes of such adult cells as skin cells. This turns back the developmental clock almost all the way – but not completely – to an embryonic-stem-cell-like state.

Dr. Jacob Hanna of the Institute’s Molecular Genetics Department and his team, including research students Ohad Gafni and Leehee Weinberger, and researchers in the Israel National Center for Personalized Medicine, realized that inserting genes to reset the stem cells was not enough. One also has to halt the cells’ drive to differentiate.

One hint that this might be possible was the fact that the mouse embryonic stem cells used in many lab experiments are easily preserved in their “naïve,” unprimed state, and they don’t present some of the other problems that human ones do. Hanna and his group realized that if they could understand how the mouse embryonic stem cells manage to refrain from differentiating in the lab, they could apply it to the human versions.

Through lab experiments and genetic analysis, they worked out a “treatment” for the iPS cells in the lab dish to damp down the genetic pathway for differentiation.

Next, they injected the treated iPS cells into mouse blastocysts – early-stage embryos containing only a few cells. If the team’s iPS cells were truly naïve, as well as viable, they would grow together with the mouse cells. Adding a fluorescent marker to the iPS cells enabled them to trace what happened to those stem cells in the developing embryo.

Fluorescent imaging after ten days (they were not grown to term) indeed revealed that the embryos contained both mouse and human tissues. The work is published in Nature.


“These cells correspond to the earliest stages of human embryonic stem cells that have been isolated. We managed to freeze what is essentially a very fleeting situation and to produce a new, naïve, pluripotent state in stem cells.”

Dr. Jacob Hanna, Molecular Genetics Department, Weizmann Institute


These findings may have many uses in biomedical research, specifically in gene therapy research, as well as genetic engineering. Hanna and his team plan to continue investigating the “humanized” mouse embryos, in which they hope to find ways of directing the development of human tissue into functional organs.

Abstract
Somatic cells can be inefficiently and stochastically reprogrammed into induced pluripotent stem (iPS) cells by exogenous expression of Oct4 (also called Pou5f1), Sox2, Klf4 and Myc (hereafter referred to as OSKM). The nature of the predominant rate-limiting barrier(s) preventing the majority of cells to successfully and synchronously reprogram remains to be defined. Here we show that depleting Mbd3, a core member of the Mbd3/NuRD (nucleosome remodelling and deacetylation) repressor complex, together with OSKM transduction and reprogramming in naive pluripotency promoting conditions, result in deterministic and synchronized iPS cell reprogramming (near 100% efficiency within seven days from mouse and human cells). Our findings uncover a dichotomous molecular function for the reprogramming factors, serving to reactivate endogenous pluripotency networks while simultaneously directly recruiting the Mbd3/NuRD repressor complex that potently restrains the reactivation of OSKM downstream target genes. Subsequently, the latter interactions, which are largely depleted during early pre-implantation development in vivo, lead to a stochastic and protracted reprogramming trajectory towards pluripotency in vitro. The deterministic reprogramming approach devised here offers a novel platform for the dissection of molecular dynamics leading to establishing pluripotency at unprecedented flexibility and resolution.

Nature 502, 65–70 (03 October 2013) doi:10.1038/nature12587
Received 03 April 2013 Accepted 23 August 2013 Published online 18 September 2013

Original press release:http://wis-wander.weizmann.ac.il/new-stem-cells-go-back-further#.UnLFLha4Q22