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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 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!




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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 ON weeks 0 - 40 and follow along every 2 weeks of fetal development
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Home | Pregnancy Timeline | News Alerts |News Archive Dec 4, 2013


The "new genetics" promises to change faulty genes of future generations
by introducing new, functioning genes using "designer sperm."

WHO Child Growth Charts




'Designer sperm' insert custom genes into offspring

New research suggests altering genes in sperm and then inducing fertilization, produces new genes that are present and active in the embryos and inherited to at least three generations.

Get ready, the "new genetics" promises to change faulty genes of future generations by introducing new, functioning genes using "designer sperm."

Research shows that introducing new genetic material using a virus for delivery — a 'vector' — into the sperm of mice leads to the presence and activity of those genes in the embryos resulting from those sperm.

This new genetic material is actually inherited, present and functioning through three generations of the mice tested.

This discovery — if successful in humans — could lead to a new frontier in genetic medicine in which diseases and disorders are effectively cured, and new human attributes, such as organ regeneration, may be possible.

The new research appears online in the FASEB Journal.

"Transgenic technology is an important tool for researching all kinds of disease in humans and animals, and for understanding crucial problems in biology," says Anil Chandrashekran, Ph.D., study author from the Department of Veterinary Clinical Sciences at The Royal Veterinary College in North Mimms, United Kingdom.

To achieve these results, Chandrashekran and colleagues used lentiviruses to generate animals via the male germ — sperm — cell line.

When lentiviral vectors encoded with green fluorescent protein (GFP) were incubated with mouse sperm, the sperm were highly successful in producing transgenic baby mice. Lentiviral induced mouse sperm were placed through in-vitro fertilization into mouse eggs and then followed after the resulting embryos were transfered into female mice.

At least 42 percent of the resulting pregnancies were transgenic for GFP. GFP expression was also detected in a wide range of rodent tissue, including testis; and, the transgene was stable through transmission to a third generation of transgenic pups.

"Using modified sperm to insert genetic material has the potential to be a major breakthrough not only in future research, but also in human medicine.

It facilitates the development of transgenic animals, and may lead to therapeutic benefits for people as well.

"For years we have chased effective gene therapies and have hit numerous speed bumps and dead ends. If we are able to able to alter sperm to improve the health of future generations, it would completely change our notions of 'preventative medicine.'"

Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal.

Transgenic technologies conventionally rely on the oocyte as a substrate for genetic modification. Owing to their accessibility, however, male germ cells, including mature sperm, have material advantages for use in transgenesis. Here we have exploited lentiviruses to generate transgenic animals via the male germline. When pseudotyped lentiviral vectors encoding green fluorescent protein (GFP) were incubated with mouse spermatozoa, these sperm were highly successful in producing transgenics. Lentivirally transduced mouse spermatozoa were used in in vitro fertilization (IVF) studies, and when followed by embryo transfer, ≥42% of founders were found to be transgenic for GFP. Inverse PCR strategy for integration site analysis demonstrated integration of at least 1 or 2 copies of GFP in the transgenics, mapping to different chromosomes. GFP expression was detected in a wide range of murine tissues, including testis and the transgene was stably transmitted to a third generation of transgenic animals. This relatively simple, yet highly efficient, technique for generating transgenic animals by transducing spermatozoa with lentiviral vectors in vitro is a powerful tool for the study of fertilization/preimplantation development, vertical viral gene transmission, gene function and regulation, and epigenetic inheritance.—Chandrashekran, A., Sarkar, R., Thrasher, A., Fraser, S.E., Dibb, N., Casimir, C., Readhead, C., Winston, R. Efficient generation of transgenic mice by lentivirus-mediated modification of spermatozoa.

Authors and Affiliations
*Department of Surgery and Cancer, Division of Cancer, Institute of Reproductive and Developmental Biology (IRDB), Imperial College London, London, UK;
†Molecular Immunology Unit, University College London Institute of Child Health, London, UK;
‡Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, California, USA; and §Department of Natural Sciences, School of Science and Technology, Middlesex University, London, UK

lentiviral vectors transgenesis male germ cells in vitro fertilization
Received May 31, 2013.
Accepted October 3, 2013.

Receive monthly highlights from The FASEB Journal by e-mail. Sign up at http://www.faseb.org/fjupdate.aspx. The FASEB Journal is published by the Federation of the American Societies for Experimental Biology (FASEB). It is among the most cited biology journals worldwide according to the Institute for Scientific Information and has been recognized by the Special Libraries Association as one of the top 100 most influential biomedical journals of the past century.

FASEB is composed of 27 societies with more than 110,000 members, making it the largest coalition of biomedical research associations in the United States. Our mission is to advance health and welfare by promoting progress and education in biological and biomedical sciences through service to our member societies and collaborative advocacy.

Details: Hypothesis: Anil Chandrashekran, Rupa Sarkar, Adrian Thrasher, Scott E. Fraser, Nicholas Dibb, Colin Casimir, Robert Winston, and Carol Readhead. Efficient generation of transgenic mice by lentivirus-mediated modification of spermatozoa. FASEB J fj.13-233999; published ahead of print December 2, 2013, doi:10.1096/fj.13-233999 ; http://www.fasebj.org/content/early/2013/11/28/fj.13-233999.abstract