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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 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
Click weeks 0 - 40 and follow fetal growth
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Home--History--Bibliography- -Pregnancy Timeline- Prescription Drugs/Pregnancy- Pregnancy Calculator - Reproductive System- -News Alerts

January 6, 2012--------News Archive

Fresh Embryos May Improve Assisted Reproduction
A new study highlights that miscarriage is less likely to occur after the transfer of fresh embryos compared to frozen-thawed embryos.

Air Pollution Link to Diabetes and Hypertension in African-American Women
The risk of diabetes increased by a significant 24 percent, and the risk of hypertension by 11 percent, with increased exposure to nitrogen oxides.

Poor Maternal Diet Can Increase Risk of Diabetes
A molecule called miR-483-3p is produced at higher levels in individuals who experienced a poor diet in their mother's wombs than those who better nourished.

January 5, 2012--------News Archive

Is Obesity in Infants “Programmed” in the Womb?
Omega 3 fatty acids eaten by pregnant women do not prevent expansive adipose tissue from developing in infants.

Progress Towards a Genital Herpes Vaccine
A vaccine under investigation protected some women against infection from one of the two types of herpes simplex the virus that causes genital herpes.

Rare Liver Disorder Kids Tolerate Mom's Graft Best
Children with a rare, life-threatening disease that is the most common cause of neonatal liver failure – biliary atresia – better tolerate liver transplants from their mothers than from their fathers, according to a UCSF-led study.

January 4, 2012--------News Archive

Simple Blood Test in First Trimester Reveals Gender
New research suggests that measuring the ratio of two enzymes in maternal blood will indicate fetal gender.

Nap-deprived Tots Missing Out On More Than Sleep
Toddlers between 2.5 and 3 years who miss only a single daily nap show more anxiety, less joy and interest and poor understanding of how to solve problems.

Women Susceptible to Infection When Ovulating
High levels of estradiol exist just prior to ovulation and decrease immune system effectiveness which can result in the growth and promotion of infection.

January 3, 2012--------News Archive

Gestational Diabetes Linked To Risk of ADHD
Maternal gestational diabetes mellitus and low socioeconomic status, appear to increase the risk of developing childhood ADHD.

Physical Activity, School Performance May Be Linked
By increasing blood and oxygen flow to the brain, and increasing endorphins which decrease stress, exercise helps improve academic performance.

January 2, 2012--------News Archive

Evolution Reveals Missing Link in DNA/Protein Shape
Despite knowing for the past 50 years that protein folds are determined by DNA sequence, fold shape complexity has limited development of disease treatments.

Bacteria Fights Fluoride in Toothpaste and in Nature
Research has uncovered the molecular tricks used by bacteria to fight the effects of fluoride, commonly used in toothpaste and mouthwash to combat tooth decay.

Gene Identified in Risk for Pancreatic Cancer
Approximately 10 percent of pancreatic cancer patients come from families with multiple cases of the disease. But finding the gene has been difficult.

WHO Child Growth Charts

What Is Your BMI?

       



By Bill Hathaway

Yale researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay.

In the Dec. 22 online issue of the journal Science Express, the researchers report that sections of RNA messages called riboswitches – which control the expression of genes — detect the build-up of fluoride and activate the defenses of bacteria, including those that contribute to tooth decay.

“These riboswitches are detectors made specifically to see fluoride,” said Ronald Breaker, the Henry Ford II Professor and chair of the Department of Molecular, Cellular and Developmental Biology and senior author of the study. Breaker writes about the combination of serendipity and scientific know-how that led his team to discover fluoride riboswitches.

Fluoride in over-the-counter and prescription toothpastes is widely credited with the large reduction in dental cavities seen since these products were made available beginning in the 1950s.

This effect is largely caused by fluoride bonding to the enamel of our teeth, which hardens them against the acids produced by bacteria in our mouths. However, it has been known for many decades that fluoride at high concentrations also is toxic to bacteria, causing some researchers to propose that this antibacterial activity also may help prevent cavities.

The riboswitches work to counteract fluoride’s effect on bacteria. “If fluoride builds up to toxic levels in the cell, a fluoride riboswitch grabs the fluoride and then turns on genes that can overcome its effects,” said Breaker.

Since both fluoride and some RNA sensor molecules are negatively charged, they should not be able to bind, he notes.

“We were stunned when we uncovered fluoride-sensing riboswitches” said Breaker. “Scientists would argue that RNA is the worst molecule to use as a sensor for fluoride, and yet we have found more than 2000 of these strange RNAs in many organisms.”

By tracking fluoride riboswitches in numerous species, the research team concluded that these RNAs are ancient — meaning many organisms have had to overcome toxic levels of fluoride throughout their history. Organisms from at least two branches of the tree of life are using fluoride riboswitches, and the proteins used to combat fluoride toxicity are present in many species from all three branches.

“Cells have had to contend with fluoride toxicity for billions of years, and so they have evolved precise sensors and defense mechanisms to do battle with this ion,” said Breaker, who is also an investigator with the Howard Hughes Medical Institute.

Now that these sensors and defense mechanisms are known, Breaker said, it may be possible to manipulate these mechanisms and make fluoride even more toxic to bacteria. Fluoride riboswitches and proteins common in bacteria are lacking in humans, and so these fluoride defense systems could be targeted by drugs. For example, the Yale team discovered protein channels that flush fluoride out of cells. Blocking these channels with another molecule would cause fluoride to accumulate in bacteria, making it more effective as a cavity fighter.

Fluoride is the 13th most common element in the earth’s crust, and it is naturally present in high concentrations throughout the United States and elsewhere. Its use in toothpaste and its addition to city water supplies across the United States sparked a controversy 60 years ago, and the dispute continues to this day. In the United Kingdom, and in other European Union countries, fluoride is used to a much lesser extent due to fierce public opposition.

The new findings from Yale only reveal how microbes overcome fluoride toxicity. The means by which humans contend with high fluoride levels remains unknown, Breaker notes. He adds that the use of fluoride has had clear benefits for dental health and that these new findings do not indicate that fluoride is unsafe as currently used.

Other Yale authors of the paper include: Jenny L. Baker, Narasimhan Sudarsan, Zasha Weinberg and Adam Roth.

The work was funded by the National Institutes of Health. Breaker is co-founder of a biotechnology company that has licensed intellectual property on riboswitches from Yale.

Original article: http://news.yale.edu/2011/12/22/how-bacteria-fight-fluoride-toothpaste-and-nature