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Methylmercury and Human Embryonic Development

Methylmercury (MeHg) is an organic form of mercury that can damage the developing brains of human fetuses. Women who consume methylmercury during pregnancy can bear children who have neurological issues because methylmercury has toxic effects on the nervous system during embryonic development. During the third week of gestation, the human nervous system begins to form in the embryo. During this gestational period, the embryo's nervous system is particularly susceptible to the influence of neurotoxins like methylmercury that can result in abnormalities.

Format: Articles

Subject: Reproduction, Disorders

The Measles, Mumps, and Rubella (MMR) Vaccine

The measles, mumps, and rubella (MMR) vaccine was created by Maurice Hilleman in 1971 at the Merck Institute of Therapeutic Research, a pharmaceutical company in West Point, Pennsylvania. It combined three separate vaccines for measles, mumps, and rubella, common and sometimes fatal diseases. Measles causes a red skin rash and severe fevers that can be fatal. Mumps causes fever and swelling of the salivary glands in the mouth and jaw, while rubella causes milder fevers and skin rashes.

Format: Articles

Subject: Technologies

Cold Spring Harbor Laboratory (1890- )

Cold Spring Harbor Laboratory (CSHL) is a non-profit research institution that specializes in cancer, neuroscience, plant biology, quantitative biology, and genomics. The organization is located on the shores of Cold Spring Harbor in Laurel Hollow, New York. The Brooklyn Institute of Arts and Sciences established the CSHL in 1890, to provide scientists with facilities to research Charles Darwin's evolutionary theory. The first mission of CSHL was biological science education.

Format: Articles

Subject: Organizations

“The Stein-Leventhal Syndrome: A Curable Form of Sterility” (1958), by Irving Freiler Stein Sr.

In 1958, Irving Freiler Stein Sr. published “The Stein-Leventhal Syndrome: A Curable Form of Sterility” documenting his findings on the diagnosis and surgical treatment of Stein-Leventhal syndrome. Stein-Leventhal syndrome, later called polycystic ovarian syndrome (PCOS), affects the reproductive health of women. Common symptoms include excess body hair, a lack of menstrual cycle or amenorrhea, and infertility. As of 2017, polycystic ovarian syndrome is considered the most common reproductive health disorder among women in the United States.

Format: Articles

Subject: Publications

Eclipse of Reason (1987)

Eclipse of Reason is a 1987 anti-abortion documentary film directed, filmed, and narrated by Bernard Nathanson, an obstetrician in the US. American Portrait Films released the film in 1987 featuring Nathanson’s commentary and footage of an abortion of a four-month-old fetus. The film also featured the testimony of women who had suffered following similar procedures. In Eclipse of Reason, Nathanson equates the fetus to a person, likening abortion procedures to murder and arguing for the illegalization of abortion.

Format: Articles

Subject: Outreach, Religion

The Formation of Reticular Theory

In the nineteenth century, reticular theory aimed to describe the properties of neurons, the specialized cells which make up the nervous system, but was later disconfirmed by evidence. Reticular theory stated that the nervous system was composed of a continuous network of specialized cells without gaps (synapses), and was first proposed by researcher Joseph von Gerlach in Germany in 1871.

Format: Articles

Subject: Theories

"Control of Corneal Differentiation by Extracellular Materials" (1974), by Stephen Meier and Elizabeth D. Hay

In 1974, Elizabeth Dexter Hay and Stephen Meier in the US conducted an experiment that demonstrated that the extracellular matrix, the mesh-like network of proteins and carbohydrates found outside of cells in the body, interacted with cells and affected their behaviors. In the experiment, Hay and Meier removed the outermost layer of cells that line the front of the eye, called corneal epithelium, from developing chick embryos.

Format: Articles

Subject: Experiments

Test-Tube Baby

A test-tube baby is the product of a successful human reproduction that results from methods beyond sexual intercourse between a man and a woman and instead utilizes medical intervention that manipulates both the egg and sperm cells for successful fertilization. The term was originally used to refer to the babies born from the earliest applications of artificial insemination and has now been expanded to refer to children born through the use of in vitro fertilization, the practice of fertilizing an embryo outside of a woman's body.

Format: Articles

Subject: Processes, Ethics, Reproduction

Acid Dissolution of Fossil Dinosaur Eggs

Acid dissolution is a technique of removing a fossil from the surrounding rock matrix in which it is encased by dissolving that matrix with acid. Fossilized bone, though strong enough to be preserved for thousands or millions of years, is often more delicate than rock. Once a fossil is discovered, scientists must remove the fossil from its surroundings without damaging the fossil itself.

Format: Articles

Subject: Technologies

"The Familial Factor in Toxemia of Pregnancy" (1968), by Leon C. Chesley, et al.

In the 1950s and 1960s, researchers Leon Chesley, John Annitto, and Robert Cosgrove investigated the possible familial factor for the conditions of preeclampsia and eclampsia in pregnant women. Preeclampsia and eclampsia, which are related to high blood pressure, have unknown causes and affect at least five percent of all pregnancies.

Format: Articles

Subject: Reproduction, Experiments, Disorders

Dandy-Walker Syndrome

Dandy-Walker Syndrome is a congenital brain defect in humans characterized by malformations to the cerebellum, the part of the brain that controls movement, and to the ventricles, the fluid-filled cavities that surround the cerebellum. The syndrome is named for physicians Walter Dandy and Arthur Walker who described associated signs and symptoms of the syndrome in the 1900s. The malformations often develop during embryonic stages.

Format: Articles

Subject: Disorders

Paul Eugen Bleuler (1857–1939)

Paul Eugen Bleuler studied autism and schizophrenia, among other psychiatric disorders, throughout continental Europe in the early twentieth century. Bleuler worked as a psychiatrist caring for patients with psychiatric disorders at a variety of facilities in Europe. In 1908, Bleuler coined the term schizophrenia to describe a group of diseases that cause changes in thought processes and behavior in humans as well as difficulties relating to the world.

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

Treatment of Anemia during Pregnancy (1931), by Lucy Wills

In 1931, physician Lucy Wills conducted a study of nutritional deficiencies that caused anemia in pregnant women in Bombay, India, later renamed Mumbai. Anemia is a lack of healthy red blood cells in the blood. Wills published the results of her study in the medical article 'Treatment of ‘Pernicious Anaemia of Pregnancy' and 'Tropical Anaemia'' in the British Medical Journal in 1931. Wills's research contributed to knowledge of anemia and the possible causes associated with the disease, such as the symptoms of fatigue and irritability.

Format: Articles

Subject: Experiments

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

Nettie Maria Stevens (1861-1912)

Multiple theories about what determines sex were tested at the turn of the twentieth century. By experimenting on germ cells, cytologist Nettie Maria Stevens collected evidence to support the connection between heredity and the sex of offspring. Stevens was able to interpret her data to conclude that chromosomes have a role in sex determination during development. For her time, she was an emerging breed: a woman of science making the leap from the world of data collection to that of male-dominated interpretive work.

Format: Articles

Subject: People, Reproduction

Sir Graham Collingwood Liggins (1926-2010)

Sir Graham Collingwood Liggins devoted much of his professional life to obstetric research. Liggins demonstrated that hormones created by the fetus helped initiate labor, rather than hormones originating solely from the mother. Liggins also discovered that cortisol given to pregnant mothers helped delay premature labor, and that it increased the likelihood that premature infants would breathe normally after birth. Prior to cortisol treatment, premature infants often died of respiratory distress syndrome characterized by the inability to inflate immature lungs.

Format: Articles

Subject: People, Reproduction

Charles Benedict Davenport (1866-1944)

Charles Benedict Davenport was an early twentieth-century experimental zoologist. Davenport founded both the Station for Experimental Evolution and the Eugenics Record Office at Cold Spring Harbor in New York. Though he was a talented statistician and skilled scientist, Davenport's scientific achievements are eclipsed by his lasting legacy as the scientific leader of the eugenics movement in the US.

Format: Articles

Subject: People, Reproduction

Johann Friedrich Meckel, the Younger (1781-1833)

Johann Friedrich Meckel studied abnormal animal and human anatomy in nineteenth century Germany in an attempt to explain embryological development. During Meckel's lifetime he catalogued embryonic malformations in multiple treatises. Meckel's focus on malformations led him to develop concepts like primary and secondary malformations, atavism, and recapitulation- all of which influenced the fields of medicine and embryology during the nineteenth and twentieth centuries.

Format: Articles

Subject: People

Nuclear Transplantation

Nuclear transplantation is a method in which the nucleus of a donor cell is relocated to a target cell that has had its nucleus removed (enucleated). Nuclear transplantation has allowed experimental embryologists to manipulate the development of an organism and to study the potential of the nucleus to direct development. Nuclear transplantation, as it was first called, was later referred to as somatic nuclear transfer or cloning.

Format: Articles

Subject: Processes

Hamburger-Hamilton Staging Series (1951)

In 1951 Viktor Hamburger and Howard Hamilton created an embryonic staging series from a combination of photographs and drawings from other researchers. The Hamburger-Hamilton stages are a sequence of images depicting 46 chronological stages in chick development. The images begin with a fertilized egg and end with a fully developed chick. The Hamburger-Hamilton staging series was produced in order to replace a previous chick staging series created in 1900. The earlier attempt lacked specific details and staged the chick embryo by using only morphological characteristics.

Format: Articles

Subject: Processes

John Tyler Bonner (1920- )

The establishment and growth of developmental-evolutionary biology owes a great debt to the work of John Tyler Bonner. Bonner's studies of cellular slime molds have shed light on some of the big questions of biology including the origins of multicellularity and the nature of morphogenesis. The second child of Lilly Marguerite Stehli and Paul Bonner, John Tyler was born 12 May 1920 in New York City and spent his early years in Locust Valley, Long Island (late 1920s), France (1930), and London (1932).

Format: Articles

Subject: People

Robert William Briggs (1911-1983)

Robert William Briggs was a prolific developmental biologist. However, he is most identified with the first successful cloning of a frog by nuclear transplantation. His later studies focused on the problem of how genes influence development.

Format: Articles

Subject: People

Muriel Wheldale Onslow (1880-1932)

Muriel Wheldale Onslow studied flowers in England with genetic and biochemical techniques in the early twentieth century. Working with geneticist William Bateson, Onslow used Mendelian principles and biochemical analysis together to understand the inheritance of flower colors at the beginning of the twentieth century. Onslow's study of snapdragons, or Antirrhinum majus, resulted in her description of epistasis, a phenomenon in which the phenotypic effect of one gene is influenced by one or more other genes. She discovered several biochemicals related to color formation.

Format: Articles

Subject: People

Thomas Hunt Morgan's Definition of Regeneration: Morphallaxis and Epimorphosis

For Thomas Hunt Morgan clarity was of utmost importance. He was therefore frustrated with the many disparate, disconnected terms that were used to refer to similar, if not the same, regenerative processes within organisms. When Morgan wrote Regeneration in 1901 there had been many different terms developed and adopted by various investigators to describe their observations. As a result there were many inconsistencies making it difficult to discuss results comparatively and also making it more challenging to generalize. Defining terms was a priority for Morgan.

Format: Articles

Subject: Theories