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Displaying 826 - 850 of 1179 items.

Shinya Yamanaka (1962- )

Shinya Yamanaka gained international prominence after publishing articles detailing the successful generation of induced pluripotent stem (iPS) cells, first in mice, then in humans. Yamanaka induced somatic cells to act like human embryonic stem cells (hESCs), allowing researchers to experiment with non-embryonic stem cells with a similar capacity as hESCs. The research involving iPS cells therefore offered new potential for research and application in medical treatment, without many of the ethical objections that hESC research entailed.

Format: Articles

Subject: People

Franz Josef Kallmann (1897–1965)

Franz Josef Kallmann studied the biological and genetic factors of psychological disorders in Germany and the United States in the twentieth century. His studies at the New York State Psychiatric Institute in New York City, New York, focused on the genetic factors that cause psychiatric disorders. Kallmann was one of the first to use twins to study how a mental disorder is passed on by comparing the occurrence of epilepsy and schizophrenia in both fraternal and identical twins.

Format: Articles

Subject: People

Eugen Steinach (1861–1944)

Eugen Steinach researched sex hormones and their effects on mammals in the late nineteenth and early twentieth centuries in Europe. He experimented on rats by removing their testicles and implanting them elsewhere in their bodies, and he found that the testes interstitial cells produce male sex hormones. He developed the Steinach Rejuvenation Procedure, which he claimed could rejuvenate men by increasing their production of sex hormones. Steinach’s work on female sex hormones and on ovarian extracts led to the development of the first standardized injectable estrogen.

Format: Articles

Subject: People

Endothelium

The endothelium is the layer of cells lining the blood vessels in animals. It weighs more than one kilogram in adult humans, and it covers a surface area of 4000 to 7000 square meters. The endothelium is the cellular interface between the circulating blood and underlying tissue. As the medium between these two sets of tissues, endothelium is part of many normal and disease processes throughout the body.

Format: Articles

Subject: Processes, Theories

Anatomia Uteri Humani Gravidi Tabulis Illustrata (The Anatomy of the Human Gravid Uterus Exhibited in Figures) (1774), by William Hunter

William Hunter’s Anatomia Uteri Humani Gravidi Tabulis Illustrata (The Anatomy of the Human Gravid Uterus Exhibited in Figures), hereafter called The Human Gravid Uterus, is an anatomical atlas depicting the pregnant form through both engravings and descriptions. William Hunter, an anatomist working in England during the eighteenth century, compiled the work based on observations from his dissections of pregnant women.

Format: Articles

Subject: Publications

Twilight Sleep

Twilight Sleep (Dammerschlaf) was a form
of childbirth first used in the early twentieth century in Germany in
which drugs caused women in labor to enter a state of sleep prior to
giving birth and awake from childbirth with no recollection of the
procedure. Prior to the early twentieth century, childbirth was
performed at home and women did not have anesthetics to alleviate the
pain of childbirth. In 1906, obstetricians Bernhardt Kronig and Karl
Gauss developed the twilight sleep method in 1906 to relieve the pain of

Format: Articles

Subject: Theories

Etienne Stephane Tarnier (1828–1897)

Etienne Stephane Tarnier was a physician who worked with premature infants in France during the nineteenth century. He worked at the Maternité Port-Royal in
Paris, France, a hospital for poor pregnant women. Tarnier developed and introduced prototypes of
infant incubators to the Maternité in 1881. Tarnier's incubators became standard in neonatal care,
especially for premature infants, enabling doctors to save many such infants that previously would
have died.

Format: Articles

Subject: People

Percivall Pott (1714-1788)

Percivall Pott was a physician in England during the eighteenth century who identified soot as the cause of chimney sweeps' scrotal cancer, later called testicular cancer. In the 1770s, Pott observed that scrotal cancer commonly afflicted chimney sweeps, the young boys sent up into chimneys to clean away the soot left over from fires, and he hypothesized that the soot inside chimneys might cause that type of cancer. Pott was one of the first doctors to identify some environmental factor as causing cancer.

Format: Articles

Subject: People

The Neuron Doctrine (1860-1895)

The neuron doctrine is a concept formed during the turn of the twentieth century that describes the properties of neurons, the specialized cells that compose the nervous system. The neuron doctrine was one of two major theories on the composition of the nervous system at the time. Advocates of the neuron doctrine claimed that the nervous system was composed of discrete cellular units. Proponents of the alternative reticular theory, on the other hand, argued that the entire nervous system was a continuous network of cells, without gaps or synapses between the cells.

Format: Articles

Subject: Theories

Intrauterine Pressure Catheter

An intrauterine pressure catheter (IUPC) is a device placed inside a pregnant woman’s uterus to monitor uterine contractions during labor. During labor, a woman’s uterus contracts to dilate, or open, the cervix and push the fetus into the birth canal. The catheter measures the pressure within the amniotic space during contractions and allows physicians to evaluate the strength, frequency, and duration of contractions.

Format: Articles

Subject: Technologies

Ethics of Fetal Surgery

Surgeons sometimes operate on the developing fetuses in utero of pregnant women as a medical intervention to treat a number of congential abnormalities, operations that have ethical aspects. A. William Liley performed the first successful fetal surgery, a blood transfusion, in New Zealand in 1963 to counteract the effects of hemolytic anemia, or Rh disease.

Format: Articles

Subject: Ethics

Nancy Goodman Brinker (1946– )

Nancy Goodman Brinker founded the largest breast cancer organization in the US, Susan G. Komen for the Cure, during the twentieth century. In 1982, Brinker created the organization, Susan G. Komen for the Cure, in memory of her sister, who had died of breast cancer two years earlier. During the early twentieth century, breast cancer was socially stigmatized, very few people discussed the disease, and there were limited treatment options available for those diagnosed with the disease.

Format: Articles

Subject: People

The Debate over DNA Replication Before the Meselson-Stahl Experiment (1953–1957)

Between 1953 and 1957, before the Meselson-Stahl experiment verified semi-conservative replication of DNA, scientists debated how DNA replicated. In 1953, James Watson and Francis Crick proposed that DNA was composed of two helical strands that wound together in a coil. Their model suggested a replication mechanism, later termed semi-conservative replication, in which parental DNA strands separated and served as templates for the replication of new daughter strands.

Format: Articles

Subject: Theories

Andrew Francis Dixon (1868-1936)

Andrew Francis Dixon studied human anatomy and egg cells at the turn of the twentieth century in Ireland and Great Britain. Dixon studied the sensory and motor nervous system of the face, the cancellous bone tissue of the femur, supernumerary kidneys, and the urogenital system. In 1927 Dixon described a mature human ovarian follicle. This follicle, Dixon noted, contained an immature human egg cell (oocyte) with a visible first polar body and the beginnings of the second polar body.

Format: Articles

Subject: People

Hilde Mangold (1898-1924)

Hilde Mangold, previously Hilde Proescholdt, was a German embryologist and physiologist who became well known for research completed with Hans Spemann in the 1920s. As a graduate student, Mangold assisted Spemann and together they discovered and coined the term the "organizer." The organizer discovery was a crucial contribution to embryology that led to further understanding of the pattern of embryo differentiation of amphibians.

Format: Articles

Subject: People

Ernst Heinrich Philipp August Haeckel (1834-1919)

Ernst Heinrich Philipp August Haeckel was a prominent comparative anatomist and active lecturer in the late nineteenth and early twentieth centuries. He is most well known for his descriptions of phylogenetic trees, studies of radiolarians, and illustrations of vertebrate embryos to support his biogenetic law and Darwin's work with evolution. Haeckel aggressively argued that the development of an embryo repeats or recapitulates the progressive stages of lower life forms and that by studying embryonic development one could thus study the evolutionary history of life on earth.

Format: Articles

Subject: People

Caspar Friedrich Wolff (1734-1794)

Caspar Friedrich Wolff is most famous for his 1759 doctoral dissertation, Theoria Generationis, in which he described embryonic development in both plants and animals as a process involving layers of cells, thereby refuting the accepted theory of preformation: the idea that organisms develop as a result of the unfolding of form that is somehow present from the outset, as in a homunculus. This work generated a great deal of controversy and discussion at the time of its publication but was an integral move in the reemergence and acceptance of the theory of epigenesis.

Format: Articles

Subject: People

The Whelan Method of Sex Selection

The Whelan Method of Sex Selection is a method for increasing a couple’s probability of conceiving an infant of the desired sex through timing intercourse. Elizabeth Whelan, a public health researcher, suggested that couples only have intercourse at specific times during the woman’s menstrual cycle based on whether they wanted a female or male infant. Whelan published her method in her book, Boy or Girl, in 1977.

Format: Articles

Subject: Technologies

The Case Against Perfection: Ethics in the Age of Genetic Engineering (2007), by Michael J. Sandel

The Case against Perfection: Ethics in the Age of Genetic Engineering, hereafter referred to as The Case against Perfection, written by Michael J. Sandel, builds on a short essay featured in The Atlantic Monthly magazine in 2004. Three years later, Sandel transformed his article into a book, keeping the same title but expanding upon his personal critique of genetic engineering. The purpose of Sandel's book is to articulate the sources of what he considers to be widespread public unease related to genetic engineering that changes the course of natural development.

Format: Articles

Subject: Publications, Ethics

George W. Beadle's One Gene-One Enzyme Hypothesis

The one gene-one enzyme hypothesis, proposed by George Wells Beadle in the US in 1941, is the theory that each gene directly produces a single enzyme, which consequently affects an individual step in a metabolic pathway. In 1941, Beadle demonstrated that one gene in a fruit fly controlled a single, specific chemical reaction in the fruit fly, which one enzyme controlled.

Format: Articles

Subject: Theories

Stem Cells

According to the US National Institutes of Health (NIH), the standard American source on stem cell research, three characteristics of stem cells differentiate them from other cell types: (1) they are unspecialized cells that (2) divide for long periods, renewing themselves and (3) can give rise to specialized cells, such as muscle and skin cells, under particular physiological and experimental conditions. When allowed to grow in particular environments, stem cells divide many times. This ability to proliferate can yield millions of stem cells over several months.

Format: Articles

Subject: Processes

Bicoid

Bicoid is the protein product of a maternal-effect gene unique to flies of the genus Drosophila . In 1988 Christiane Nüsslein-Volhard identified bicoid as the first known morphogen . A morphogen is a molecule that determines the fate and phenotype of a group of cells through a concentration gradient across that developing region. The bicoid gradient, which extends across the anterior-posterior axis of Drosophila embryos, organizes the head and thorax.

Format: Articles

Subject: Processes

Edward Drinker Cope (1840-1897)

Edward Drinker Cope studied fossils and anatomy in the US in the late nineteenth century. Based on his observations of skeletal morphology, Cope developed a novel mechanism to explain the law of parallelism, the idea that developing organisms successively pass through stages resembling their ancestors. Others had proposed the addition of new body forms at the end of an individual organism's developed as a mechanism through which new species arose, but those proposals relied on changes in the lengths of gestation or incubation.

Format: Articles

Subject: People

American Eugenics Society (1926-1972)

The American Eugenics Society (AES) was established in the US by
Madison Grant, Harry H. Laughlin, Henry Crampton, Irving Fisher, and
Henry F. Osborn in 1926 to promote eugenics education programs for
the US public. The AES described eugenics as the study of improving
the genetic composition of humans through controlled reproduction of
different races and classes of people. The AES aided smaller eugenic
efforts such as the Galton Society in New York, New York, and the

Format: Articles

Subject: Organizations

Chernobyl Heart (2003)

In 2003, HBO Original Programming released the documentary Chernobyl Heart. Maryann De Leo directed and produced the film, which is about the Chernobyl nuclear power plant accident and how the radiation from that accident has affected people living in the area. Side effects have included mental disabilities, physical disabilities, and genetic mutations.

Format: Articles

Subject: Outreach