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Green Fluorescent Protein

Green fluorescent protein (GFP) is a protein in the jellyfish Aequorea Victoria that exhibits green fluorescence when exposed to light. The protein has 238 amino acids, three of them (Numbers 65 to 67) form a structure that emits visible green fluorescent light. In the jellyfish, GFP interacts with another protein, called aequorin, which emits blue light when added with calcium. Biologists use GFP to study cells in embryos and fetuses during developmental processes.

Format: Articles

Subject: Technologies

David Hunter Hubel (1926–2013)

David Hunter Hubel studied the development of the visual system and how the brain processes visual information in the US during the twentieth century. He performed multiple experiments with kittens in which he sewed kitten’s eyes shut for varying periods of time and monitored their vision after reopening them. Hubel, along with colleague Torsten Wiesel, received the 1981 Nobel Prize in Physiology or Medicine for that research.

Format: Articles

Subject: People

Solomon A. Berson (1918-1972)

Solomon A. Berson helped develop the radioimmunoassay (RIA) technique in the US during the twentieth century. Berson made many scientific contributions while working with research partner Rosalyn Yalow at the Bronx Veterans Administration (VA) hospital, in New York City, New York. In the more than twenty years that Berson and Yalow collaborated, they refined the procedures for tracing diagnostic biological compounds using isotope labels.

Format: Articles

Subject: People

“A Linkage Between DNA Markers on the X Chromosome and Male Sexual Orientation” (1993), by Dean H. Hamer and Charles A. Thomas.

In 1993, Dean H. Hamer and colleagues in the US published results from their research that indicated that men with speicifc genes were more likely to be homosexual than were men without those genes. The study hypothesized that some X chromosomes contain a gene, Xq28, that increases the likelihood of an individual to be homosexual. Prior to those results, researchers had argued that the cause of homosexuality was environmental and that homosexuality could be altered or reversed. Hamer’s research suggested a possible genetic cause of homosexuality.

Format: Articles

Subject: Experiments

The Boys from Brazil (1978)

The Boys from Brazil is a science fiction film based on the novel of the same name by Ira Levin about an underground neo-Nazi society in South America trying to clone Adolf Hitler, the dictator of Nazi Germany during World War II, to restore the Nazi movement. The film was directed by Franklin Schaffner and released in 1978 by 20th Century Fox in Los Angeles, California. The Boys from Brazil is a film that was one of the first films to depict cloning, and to discuss the ethical implications of genetic engineering, cloning, and eugenics.

Format: Articles

Subject: Publications

Leonard Colebrook (1883–1967)

Leonard Colebrook was a physician who researched bacteria and infections in England during the twentieth century. In 1936, Colebrook deployed the antibiotic Prontosil to treat puerperal fever, a disorder that results from bacterial infections in the uterine tracts of women after childbirth or abortions. Colebrook also advanced care for burn patients by advocating for the creation of burn units in hospitals and by using antisepsis medication for burn wound infections. Colebrook’s work on treatments for puerperal fever reduced cases of puerperal fever throughout the world.

Format: Articles

Subject: People

Richard Doll (1912–2005)

Richard Doll was an epidemiologist and public figure in the twentieth and early twenty-first centuries. Working primarily at the University of Oxford, in Oxford, England, Doll established a definitive correlation between cigarette smoking and lung cancer. Furthermore, Doll’s work helped legitimize epidemiology as a scientific discipline. Doll’s research also helped establish modern guidelines for oncological studies, as well as for contemporary and future research on the effect of smoking on pregnancy and fetal development.

Format: Articles

Subject: People

The Comstock Law (1873)

The Comstock Law was a controversial law because it limited the reproductive rights of women and violated every person's right to privacy. This federal law was the beginning of a long fight over the reproductive rights of women which is still being waged. Reproductive rights are important to embryology because they lead to the discussions regarding the morality of abortion, contraceptives, and ultimately the moral status of the embryo.

Format: Articles

Subject: Legal, Reproduction

Roy John Britten (1919-2012)

Roy John Britten studied DNA sequences in the US in the second
half of the twentieth century, and he helped discover repetitive
elements in DNA sequences. Additionally, Britten helped propose
models and concepts of gene regulatory networks. Britten studied the
organization of repetitive elements and, analyzing data from the
Human Genome Project, he found that the repetitive elements in DNA
segments do not code for proteins, enzymes, or cellular parts.
Britten hypothesized that repetitive elements helped cause cells to

Format: Articles

Subject: People

The Guthrie Test for Early Diagnosis of Phenylketonuria

The Guthrie test, also called the PKU test, is a diagnostic tool to test infants for phenylketonuria a few days after birth. To administer the Guthrie test, doctors use Guthrie cards to collect capillary blood from an infant’s heel, and the cards are saved for later testing. Robert Guthrie invented the test in 1962 in Buffalo, New York. Phenylketonuria (PKU) is a congenital birth abnormality in which toxic levels of the amino acid phenylalanine build up in the blood, a process that affects the brains in untreated infants.

Format: Articles

Subject: Technologies

"The Chemical Basis of Morphogenesis" (1952), by Alan M. Turing

In 1952 the article "The Chemical Basis of Morphogenesis" by the British mathematician and logician Alan M. Turing was published in Philosophical Transactions of the Royal Society of London. In that article Turing describes a mathematical model of the growing embryo. He uses this model to show how embryos develop patterns and structures (e.g., coat patterns and limbs, respectively). Turing's mathematical approach became fundamental for explaining the developmental process of embryos.

Format: Articles

Subject: Publications

Epigenetic Landscape

The epigenetic landscape is a concept representing embryonic development. It was proposed by Conrad Hal Waddington to illustrate the various developmental pathways a cell might take toward differentiation. The epigenetic landscape integrates the connected concepts of competence, induction, and regulative abilities of the genes into a single model designed to explain cellular differentiation, a long standing problem in embryology.

Format: Articles

Subject: Theories

The Fruits of Philosophy (1832), by Charles Knowlton

In 1832, Charles Knowlton published The Fruits of Philosophy, a pamphlet advocating for controlling reproduction and detailing methods for preventing pregnancy. Originally published anonymously in Massachusetts, The Fruits of Philosophy was an illegal book because United States law prohibited the publishing of immoral and obscene material, which included information about contraception. In The Fruits of Philosophy, Knowlton detailed recipes for contraceptives and advocated for controlling reproduction.

Format: Articles

Subject: Publications

The Shettles Method of Sex Selection

In the 1960s in the United States Landrum B. Shettles developed the Shettles method, which is a procedure for couples to use prior to and during an intercourse to increase their chances of conceiving a fetus of their desired sex. Shettles, a physician, who specialized in obstetrics and gynecology, found a difference in the size and shape of male sperm cells that he correlated with the different sex chromosomes they carry.

Format: Articles

Subject: Technologies, Reproduction

Francis Harry Compton Crick (1916-2004)

Francis Harry Compton Crick, who co-discovered the structure of deoxyribonucleic acid (DNA) in 1953 in Cambridge, England, also developed The Central Dogma of Molecular Biology, and further clarified the relationship between nucleotides and protein synthesis. Crick received the Nobel Prize in Physiology or Medicine that he shared with James Watson and Maurice Wilkins in 1962 for their discovery of the molecular structure of DNA.

Format: Articles

Subject: People

Martius Flap Procedure to Repair Obstetric Fistulas

The Martius flap procedure is a surgical procedure used to treat obstetric fistulas in women. Heinrich Martius developed the procedure in twentieth century Germany to treat women with urinary incontinence caused by stress, and later doctors used it to repair obstetric fistulas. Fistulas occur in pregnant women when a hole is torn between the vagina and the urinary tract (called vesicovaginal) or the vagina and the rectum (called rectovaginal). The hole, or fistula, occurs in the tissue separating two organs and therefore obstetric fistulas result in either urinary or fecal incontinence.

Format: Articles

Subject: Technologies, Disorders

Ameisen: Die heimliche Weltmacht (Ants: Nature’s Secret Power) (2004)

Ameisen: Die heimliche Weltmacht (Ants: Nature’s Secret Power) is a nature documentary about ants. Wolfgang Thaler wrote, filmed, and directed the film, which focuses on the work of ant researcher Bert

Format: Articles

Subject: Outreach

Andrew Zachary Fire (1959- )

Andrew Zachary Fire is a professor at Stanford University and Nobel Laureate. Fire worked at the Carnegie Institution of Washington's Department of Embryology in Baltimore, Maryland, with colleague Craig Mello, where they discovered that RNA molecules could be used to turn off or knock out the expression of genes. Fire and Mello called the process RNA interference (RNAi), and won the Nobel Prize in Physiology or Medicine in 2006 for their discovery.

Format: Articles

Subject: People

Stem Cell Tourism

When James Thomson of the University of Wisconsin announced in 1998 that he had derived and cultured human embryonic stem cells(hESCs), Americans widely believed-and accepted-that stem cells would one day be the basis of a multitude of regenerative medical techniques. Researchers promised that they would soon be able to cure a variety of diseases and injuries such as cancer, diabetes, Parkinson's, spinal cord injuries, severe burns, and many others. But it wasn't until January 2009 that the Food and Drug Administration approved the first human clinical trials using hESCs.

Format: Articles

Subject: Theories, Ethics

David Wildt's Domestic Cat and Cheetah Experiments (1978-1983)

David Wildt's cheetah (Acinonyx jubatus) research from 1978-1983 became the foundation for the use of embryological techniques in endangered species breeding programs. The cheetah is a member of the cat family (Felidae), which includes thirty-seven species. According to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) all Felidae species are currently threatened or endangered, with the exception of the domestic cat (Felinus catus).

Format: Articles

Subject: Experiments

In re Marriage of Witten (2003)

In re Marriage of Witten, decided by the Iowa Supreme Court in 2003, held that neither Tamera nor Arthur (Trip) Witten could use or destroy several cryopreserved preembryos created during their marriage using in vitro fertilization (IVF), unless the former couple could reach a mutual agreement. Tamera and Trip Witten, unable to conceive conventionally during their marriage, had attempted to start a family together using IVF at the University of Nebraska Medical Center (UNMC) in Omaha, Nebraska.

Format: Articles

Subject: Legal

The Malthusian League (1877–1927)

The Malthusian League, founded in London, England, in 1877 promoted the use of contraception to limit family size. Activists Charles Bradlaugh and Annie Besant established the Malthusian League after they were arrested and exonerated for publishing a pamphlet describing techniques to prevent pregnancy. Founders based the league on the principles of Thomas Malthus, a British nineteenth century economist, who wrote on the perils of a population growing beyond the resources available to support it.

Format: Articles

Subject: Organizations, Outreach, Reproduction

Stafford Leak Warren (1896–1981)

Stafford Leak Warren studied nuclear medicine in the United States during the twentieth century. He used radiation to make images of the body for diagnosis or treatment and developed the mammogram, a breast imaging technique that uses low-energy X-rays to produce an image of breasts. Mammograms allow doctors to diagnose breast cancer in its early and most treatable stages.

Format: Articles

Subject: People

“Perimortem Cesarean Delivery” (1986), by Vern Katz, Deborah Dotters, and William Droegemueller

In 1986, Vern L. Katz, Deborah J. Dotters, and William Droegemueller published “Perimortem Cesarean Delivery,” an article in which they developed the Four Minute Rule for perimortem cesarean sections. The Four Minute Rule states that if a pregnant woman’s heart stops beating, physicians should begin an operation to deliver the fetus within four minutes and aim to have the fetus delivered within five minutes of cardiac arrest.

Format: Articles

Subject: Publications

On the Generation of Animals, by Aristotle

Aristotle's On the Generation of Animals is referred to in Latin as De Generatione animalium. As with many of Aristotle's writings, the exact date of authorship is unknown, but it was produced in the latter part of the fourth century B.C. This book is the second recorded work on embryology that is treated as a subject of philosophy, being preceded by contributions in the Hippocratic corpus by about a century.

Format: Articles

Subject: Publications