Search

Displaying 526 - 550 of 1179 items.

Ernst Gräfenberg (1881–1957)

Ernst Gräfenberg was a physician and researcher who studied sexology, the study of human sexuality, in both Germany and the United States during the first half of the twentieth century. Gräfenberg researched the use of intrauterine devices as a form of contraception, and he developed the Gräfenberg ring. The Gräfenberg ring was one of the first intrauterine devices that effectively prevented pregnancy without causing infection, and it became the forerunner of all modern intrauterine devices, or IUDs. Gräfenberg also studied the role of the urethra in female orgasm.

Format: Articles

Subject: People, Technologies, Reproduction

Rosalyn Sussman Yalow (1921-2011)

Rosalyn Sussman Yalow co-developed the radioimmunoassay (RIA), a method used to measure minute biological compounds that cause immune systems to produce antibodies. Yalow and research partner Solomon A. Berson developed the RIA in the early 1950s at the Bronx Veterans Administration (VA) Hospital, in New York City, New York. Yalow and Berson's methods expanded scientific research, particularly in the medical field, and contributed to medical diagnostics. For this achievement, Yalow received the Nobel Prize in Physiology or Medicine in 1977.

Format: Articles

Subject: People

Leon Chesley (1908-2000)

Leon Chesley studied hypertension, or high blood pressure, in pregnant women during the mid-twentieth century. Chesley studied preeclampsia and eclampsia, two hypertensive disorders found in approximately five percent of all US pregnancies. In New Jersey and New York, Chesley devoted over forty years to researching preeclampsia and eclampsia. Chesley conducted several long-term studies using the same group of women beginning from their pregnancies.

Format: Articles

Subject: People, Reproduction

Theodor Heinrich Boveri (1862-1915)

Theodor Boveri investigated the mechanisms of heredity. He developed the chromosomal theory of inheritance and the idea of chromosomal individuality. Boveri sought to provide a comprehensive explanation for the hereditary role and behavior of chromosomes. He hoped that his experiments would also help to distinguish the roles of the nucleus and the cytoplasm in embryogenesis. Boveri was particularly interested in how offspring are shaped by the attributes of their parents.

Format: Articles

Subject: People

Richard Woltereck's Concept of Reaktionsnorm

Richard Woltereck first described the concept of Reaktionsnorm (norm of reaction) in his 1909 paper 'Weitere experimentelle Untersuchungen uber Art-veranderung, speziell uber das Wesen quantitativer Artunterschiede bei Daphniden' ('Further investigations of type variation, specifically concerning the nature of quantitative differences between varieties of Daphnia'). This concept refers to the ways in which the environment can alter the development of an organism, and its adult characteristics.

Format: Articles

Subject: Theories

Neurocristopathies

Neurocristopathies are a class of pathologies in vertebrates,
including humans, that result from abnormal expression, migration,
differentiation, or death of neural crest cells (NCCs) during embryonic development. NCCs are cells
derived from the embryonic cellular structure called the neural crest.
Abnormal NCCs can cause a neurocristopathy by chemically affecting the
development of the non-NCC tissues around them. They can also affect the
development of NCC tissues, causing defective migration or

Format: Articles

Subject: Theories

Elinor Catherine Hamlin (1924- )

Elinor Catherine Hamlin founded and helped fund centers in Ethiopia to treat women affected by fistulas from obstetric complications. Obstetric fistulas develop in women who experience prolonged labor, as the pressure placed on the pelvis by the fetus during labor causes a hole, or fistula, to form between the vagina and the bladder (vesicovaginal fistula) or between the vagina and the rectum (rectovaginal fistula). Both of those conditions result in urinary or fecal incontinence, which often impacts womenÍs social status within their communities.

Format: Articles

Subject: People, Reproduction

Telomerase in Human Development

Telomerase is an enzyme that regulates the lengths of telomeres in the cells of many organisms, and in humans it begins to function int the early stages of embryonic development. Telomeres are repetitive sequences of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling. In 1989, Gregg Morin found that telomerase was present in human cells. In 1996, Woodring Wright and his team examined human embryonic cells and found that telomerase was active in them. Scientists manipulate telomerase in cells to give cells the capacity to replicate infinitely.

Format: Articles

Subject: Theories

The Jane Collective (1969–1973)

The Jane Collective was an underground organization that provided illegal abortion services in Chicago, Illinois, from 1969 until abortions became legal in 1973. Formally called the Abortion Counseling Service of Women’s Liberation, the Jane Collective was a member organization and working group within Chicago Women’s Liberation Union that challenged the Illinois state legislature by providing abortions before they were legal in the US.

Format: Articles

Subject: Organizations

James Edgar Till (1931– )

James Edgar Till is a biophysicist known for establishing the existence of stem cells along with Ernest McCulloch in 1963. Stem cells are undifferentiated cells that can shift, or differentiate, into specialized types of cells and serve as a repair system in the body by dividing indefinitely to replenish other cells. Till’s work with stem cells in bone marrow, which produces the body’s blood cells, helped form the field of modern hematology, a medical discipline that focuses on diseases related to the blood.

Format: Articles

Subject: People, Experiments, Technologies

Thomas Henry Huxley (1825-1895)

In nineteenth century Great Britain, Thomas Henry Huxley proposed connections between the development of organisms and their evolutionary histories, critiqued previously held concepts of homology, and promoted Charles Darwin's theory of evolution. Many called him Darwin's Bulldog. Huxley helped professionalize and redefine British science. He wrote about philosophy, religion, and social issues, and researched and theorized in many biological fields.

Format: Articles

Subject: People

Luc Antoine Montagnier (1932-2022)

Luc Montagnier studied viruses, the immune system, and cancer in France during the second half of the twentieth century. In his early career, Montagnier studied how cancer-causing viruses replicate and infect host cells. He received the Nobel Prize in Physiology or Medicine in 2008 for his team’s discovery that a retrovirus, human immunodeficiency virus, or HIV, was the cause of acquired immunodeficiency syndrome, or AIDS. AIDS is a chronic condition that results from HIV infection and damages the immune system.

Format: Articles

Subject: People, Processes, Experiments

William Thornton Mustard (1914-1987)

William Thornton Mustard was a surgeon in Canada during the twentieth century who developed surgical techniques to treat children who had congenital heart defects. Mustard has two surgeries named after him, both of which he helped to develop. The first of these surgeries replaces damaged or paralyzed muscles in individuals who have polio, a virus that can cause paralysis. The other technique corrects a condition called the transposition of the great arteries (TGA) that is noticed at birth.

Format: Articles

Subject: People, Disorders, Disorders

Betty Friedan (1921–2006)

Betty Friedan advocated for the advancement of women's rights in the twentieth century in the United States. In 1963, Friedan wrote The Feminine Mystique, which historians consider a major contribution to the feminist movement. Friedan also helped establish two organizations that advocated for women's right, the National Organization for Women (NOW) in 1963 and, in 1969 the National Association for the Repeal of Abortion Laws (NAARL). Friedan argued for legalizing access to abortion and contraception, and her advocacy helped advance women's reproductive rights.

Format: Articles

Subject: People

David Baltimore (1938– )

David Baltimore studied viruses and the immune system in the US during the twentieth century. In 1975, Baltimore was awarded the Nobel Prize in Physiology or Medicine for discovering reverse transcriptase, the enzyme used to transfer information from RNA to DNA. The discovery of reverse transcriptase contradicted the central dogma of biology at the time, which stated that the transfer of information was unidirectional from DNA, RNA, to protein.

Format: Articles

Subject: People

The Baby Doe Rules (1984)

The Baby Doe Rules represent the first attempt by the US government to directly intervene in treatment options for neonates born with congenital defects. The name of the rule comes from the controversial 1982 case of a Bloomington, Indiana infant Baby Doe, a name coined by the media. The Baby Doe Rules mandate that, as a requirement for federal funding, hospitals and physicians must provide maximal care to any impaired infant, unless select exceptions are met. If a physician or parent chooses to withhold full treatment when the exceptions are not met, they are liable for medical neglect.

Format: Articles

Subject: Legal, Reproduction

August Friedrich Leopold Weismann (1834-1914)

August Friedrich Leopold Weismann studied how the traits of organisms developed and evolved in a variety of organisms, mostly insects and aquatic animals, in Germany in the late nineteenth and early twentieth centuries. Weismann proposed the theory of the continuity of germ-plasm, a theory of heredity. Weismann postulated that germ-plasm was the hereditary material in cells, and parents transmitted to their offspring only the germ-plasm present in germ-cells (sperm and egg cells) rather than somatic or body cells.

Format: Articles

Subject: People

Mesoderm

Mesoderm is one of the three germ layers, groups of cells that interact early during the embryonic life of animals and from which organs and tissues form. As organs form, a process called organogenesis, mesoderm interacts with endoderm and ectoderm to give rise to the digestive tract, the heart and skeletal muscles, red blood cells, and the tubules of the kidneys, as well as a type of connective tissue called mesenchyme. All animals that have only one plane of symmetry through the body, called bilateral symmetry, form three germ layers.

Format: Articles

Subject: Processes

“Levator Trauma is Associated with Pelvic Organ Prolapse” (2008), by Hans P. Dietz and Judy M. Simpson

Hans Peter Dietz and Judy Simpson published, “Levator Trauma is Associated with Pelvic Organ Prolapse,” in the journal BJOG: An International Journal of Obstetrics and Gynecology in 2008. In their article, Dietz and Simpson estimated the risk of pelvic organ prolapse in women who attained injuries to the pelvic levator muscles. The levator muscles, also known as the levator ani, are a major muscle group that comprise the pelvic floor. Along with other muscles, the pelvic floor supports organs in a woman’s pelvis, such as the bladder, uterus, and rectum.

Format: Articles

Subject: Publications, Disorders

William John Little (1810–1894)

William John Little was one of the first orthopedic surgeons to research congenital malformations and their causes in the nineteenth century and presented preliminary research on a condition modernly known as cerebral palsy, a condition of varying severity that affects a person’s ability to move. Little worked throughout the United Kingdom for the majority of the time he practiced medicine, and eventually founded one of the first orthopedic infirmaries, the Royal Orthopedic Hospital in London, England.

Format: Articles

Subject: People, Disorders

Virginia Apgar (1909–1974)

Virginia Apgar worked as an obstetrical anesthesiologist, administering drugs that reduce women’s pain during childbirth, in the US in the mid-twentieth century. In 1953, Apgar created a scoring system using five easily assessable measurements, including heart rate and breathing rate, to evaluate whether or not infants would benefit from medical attention immediately after birth. Apgar’s system showed that infants who were previously set aside as too sick to survive, despite low Apgar scores, could recover with immediate medical attention.

Format: Articles

Subject: People, Reproduction

Stanley Alan Plotkin (1932– )

Stanley Alan Plotkin developed vaccines in the United States during the mid to late twentieth century. Plotkin began his research career at the Wistar Institute in Philadelphia, Pennsylvania, where he studied the rubella virus. In pregnant women, the rubella virus caused congenital rubella syndrome in the fetus, which led to various malformations and birth defects. Using WI-38 cells, a line of cells that originated from tissues of aborted fetuses, Plotkin successfully created RA27/3, a weakened strain of the rubella virus, which he then used to develop a rubella vaccine.

Format: Articles

Subject: People

Pope Gregory XIV (1535-1591)

Pope Gregory XIV, born Nicolo Sfondrati, reversed the bull of Pope Sixtus V, Effraenatum, under which an abortion at any time of gestation can be punished by excommunication. He supported the Aristotelian distinction between an "animated" and "unanimated" fetus, making abortion of an unanimated fetus punishable by lesser means. This decision contributed to the historical debates within the Roman Catholic Church on when a fetus has a soul, and when abortion was punishable by excommunication.

Format: Articles

Subject: People, Religion, Reproduction

Enovid: The First Hormonal Birth Control Pill

Enovid was the first hormonal birth control pill. G. D. Searle and Company began marketing Enovid as a contraceptive in 1960. The technology was created by the joint efforts of many individuals and organizations, including Margaret Sanger, Katharine McCormick, Gregory Pincus, John Rock, Syntex, S.A. Laboratories, and G.D. Searle and Company Laboratories.

Format: Articles

Subject: Technologies, Reproduction

Conjoined Twins

Conjoined twins are twins whose bodies are anatomically joined in utero. The degree to which the twins are attached can range from simple, involving skin and cartilage, to complex, including fusion of the skull(s), brain(s), or other vital organs. There are more than a dozen classifications of conjoined twins but what they all tend to have in common is the sharing of the chorion, placenta, and amniotic sac.

Format: Articles

Subject: Disorders, Reproduction