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Leonard Hayflick (1928- )
Leonard Hayflick studied the processes by which cells age during the twentieth and twenty-first centuries in the United States. In 1961 at the Wistar Institute in the US, Hayflick researched a phenomenon later called the Hayflick Limit, or the claim that normal human cells can only divide forty to sixty times before they cannot divide any further. Researchers later found that the cause of the Hayflick Limit is the shortening of telomeres, or portions of DNA at the ends of chromosomes that slowly degrade as cells replicate.
Format: Articles
Subject: People
US Regulatory Response to Thalidomide (1950-2000)
Thalidomide, a drug capable of causing fetal abnormalities (teratogen), has caused greater than ten thousand birth defects worldwide since its introduction to the market as a pharmaceutical agent. Prior to discovering thalidomide's teratogenic effects in the early 1960s, the US Food and Drug Administration (FDA) did not place regulations on drug approval or monitoring as it later did. By 1962, approximately 20,000 patients in the US had taken thalidomide as part of an unregulated clinical trial before any actions were taken to stop thalidomide's distribution.
Format: Articles
Subject: Legal, Reproduction
US Food and Drug Administration’s Requirements on Content and Format for Labeling for Human Prescription Drugs Rule (1979)
Format: Articles
Subject: Legal
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
Paul Kammerer's Experiments on the Midwife Toad (1905-1910)
In the first decade of the twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, conducted research on developmental mechanisms, including a series of breeding experiments on toads (Alytes obstetricans). Kammerer claimed that his results demonstrated that organisms could transmit acquired characteristics to their offspring.
Format: Articles
Subject: Experiments
Amphioxus, and the Mosaic Theory of Development (1893), by Edmund Beecher Wilson
Edmund Beecher Wilson experimented with Amphioxus (Branchiostoma) embryos in 1892 to identify what caused their cells to differentiate into new types of cells during the process of development. Wilson shook apart the cells at early stages of embryonic development, and he observed the development of the isolated cells. He observed that in the normal development of Amphioxus, all three main types of symmetry, or cleavage patterns observed in embryos, could be found. Wilson proposed a hypothesis that reformed the Mosaic Theory associated with Wilhelm Roux in Germany.
Format: Articles
Subject: Experiments
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
Catherine DeAngelis (1940– )
In the late-twentieth century in the United States, Catherine DeAngelis was a pediatric physician, researcher, and editor of multiple medical journals. During her time with the Journal of the American Medical Association, DeAngelis became the journal’s first female editor. At Johns Hopkins University in Baltimore, Maryland, she studied how physician-nurse interactions affected patient care, how immunizations and adolescent pregnancy affected children, and how medications affected men and women differently.
Format: Articles
Subject: People
Richard Woltereck (1877-1944)
Richard Woltereck was a German zoologist and hydrobiologist who studied aquatic animals and extended the concept of Reaktionsnorm (norm of reaction) to the study of genetics. He also provided some of the first experimental evidence for the early twentieth-century embryological theory of heredity known as cytoplasmic inheritance. Through experiments on the water flea, Daphnia, Woltereck investigated whether variation produced by environmental impacts on development could play a role in heredity and evolution.
Format: Articles
Subject: People
Isotretinoin (Accutane) as a Teratogen
Isotretinoin is a molecule and a byproduct (metabolite) of vitamin A, and in greater than normal amounts in pregnant women, it can cause fetal abnormalities including cleft lips, ear and eye defects, and mental retardation. Isotretinoin is commonly called by its trade name Accutane, and it's a chemical compound derived from vitamin A, or retinoic acid. Doctors prescribe isotretinoin to treat severe acne. For pregnant women, too much vitamin A or isotretinoin can also cause greater than normal rates of stillbirths and fetal disintegrations after the ninth week of gestation.
Format: Articles
Subject: Reproduction, Disorders
“Invasive and Non-invasive Methods for the Diagnosis of Endometriosis” (2010), by Albert L. Hsu, Izabella Khachikyan, and Pamela Stratton
In 2010, Albert L. Hsu, Izebella Khchikyan, and Pamela Stratton published “Invasive and Non-invasive Methods for the Diagnosis of Endometriosis,” henceforth “Methods for the Diagnosis of Endometriosis,” in Clinical Obstetrics and Gynecology. In the article, the authors describe how specific types of endometriotic lesions appear in the body and evaluate five methods for diagnosing endometriosis. Endometriosis is the growth of endometrium, the tissue that normally lines the inside of the uterus, outside of the uterus.
Format: Articles
Subject: Publications
“Traditional postpartum practices and rituals: a qualitative systematic review” (2007), by Cindy-Lee Dennis, Kenneth Fung, Sophie Grigoriadis, Gail Erlick Robinson, Sarah Romans and Lori Ross
In the 2007 paper “Traditional postpartum practices and rituals: a qualitative systematic review,” Toronto-based researchers showed that women from different cultures around the world follow similar postpartum practices after giving birth. At the University of Toronto in Toronto, Canada, Cindy-Lee Dennis, Kenneth Fung, Sophie Grigoriadis, Gail Erlick Robinson, Sarah Romans, and Lori Ross examined fifty-one studies from over twenty countries that focused on traditional postpartum practices.
Format: Articles
Subject: Publications
Ernest John Christopher Polge (1926-2006)
Twentieth-century researcher Ernest John Christopher Polge studied the reproductive processes of livestock and determined a method to successfully freeze, thaw, and utilize viable sperm cells to produce offspring in animals. In 1949, Polge identified glycerol as a cryoprotectant, or a medium that enables cells to freeze without damaging their cellular components or functions. Several years later, Polge used glycerol in a freezing process called vitrification, which enabled him to freeze poultry sperm, thaw that sperm, and use it to fertilize vertebrate embryos.
Format: Articles
Subject: People
Ziegler Wax Embryo Models
Three-dimensional anatomical models have long been essential to the learning of science and lend a sense of "control" to those practicing in the field. As the development of embryology grew in importance during the late 1800s, so did the need for models to show intricate details of embryos.
Format: Articles
Subject: Technologies, Reproduction
Leo Kanner (1894-1981)
Leo Kanner studied and described early infantile autism in humans in the US during the twentieth century. Though Eugen Bleuler first coined the term autism in 1910 as a symptom of schizophrenia, Kanner helped define autism as a disease concept separate from schizophrenia. He helped found an early child psychiatry department in 1930 at the Johns Hopkins University Hospital in Baltimore, Maryland.
Format: Articles
Subject: People
Mitochondrial DNA (mtDNA)
Mitochondrial DNA (mtDNA) is located outside the nucleus in the liquid portion of the cell (cytoplasm) inside cellular organelles called Mitochondria. Mitochondria are located in all complex or eukaryotic cells, including plant, animal, fungi, and single celled protists, which contain their own mtDNA genome. In animals with a backbone, or vertebrates, mtDNA is a double stranded, circular molecule that forms a circular genome, which ranges in size from sixteen to eighteen kilo-base pairs, depending on species. Each mitochondrion in a cell can have multiple copies of the mtDNA genome.
Format: Articles
Subject: Theories
Paul Kammerer's Experiments on Salamanders (1903-1912)
In the early twentieth century, Paul Kammerer conducted a series of experiments to demonstrate that organisms could transmit characteristics acquired in their lifetimes to their offspring. In his 1809 publication, zoologist Jean-Baptiste Lamarck had hypothesized that living beings can inherit features their parents or ancestors acquired throughout life. By breeding salamanders, as well as frogs and other organisms, Kammerer tested Lamarck's hypothesis in an attempt to provide evidence for Lamarck's theory of the inheritance of acquired characteristics.
Format: Articles
Subject: Experiments
Meselson, Stahl, and the Replication of DNA: A History of "The Most Beautiful Experiment in Biology" (2001), by Frederic Lawrence Holmes
In 2001, Yale University Press published Frederic Lawrence Holmes' book, Meselson, Stahl, and the Replication of DNA: A History of "The Most Beautiful Experiment in Biology" (Replication of DNA), which chronicles the 1950s debate about how DNA replicates. That experiment verified that DNA replicates semi-conservatively as originally proposed by Watson and Crick. Rather than focusing solely on experiments and findings, Holmes's book presents the investigative processes of scientists studying DNA replication.
Format: Articles
Subject: Publications
Paul Kammerer's Experiments on Sea-squirts in the Early Twentieth Century
In the early twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, experimented on sea-squirts (Ciona intestinalis). Kammerer claimed that results from his experiments demonstrated that organisms could transmit characteristics that they had acquired in their lifetimes to their offspring. Kammerer conducted breeding experiments on sea-squirts and other organisms at a time when Charles Darwin's 1859 theory of evolution lacked evidence to explain how offspring inherited traits from their parents.
Format: Articles
Subject: Experiments, Organisms
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
Leonardo da Vinci (1452-1519)
Leonardo da Vinci was born on 15 April 1452, the illegitimate son of a young peasant girl by the name of Caterina and Ser Piero da Vinci, a well-renowned Florentine notary. Leonardo lived in Italy in the town of Vinci until his late teens and received a simple education in reading and writing as well as some training in mathematics and engineering. Although he was socially excluded by birthright from almost every profession and prohibited from attending any formal university, Leonardo went on to become a celebrated scientist, artist, and engineer.
Format: Articles
Subject: People
"In vitro Experiments on the Effects of Mouse Sarcomas 180 and 37 on the Spinal and Sympathetic Ganglia of the Chick Embryo" (1954), by Rita Levi-Montalcini, Viktor Hamburger, and Hertha Meyer
"In vitro Experiments on the Effects of Mouse Sarcomas 180 and 37 on the Spinal and Sympathetic Ganglia of the Chick Embryo" were experiments conducted by Rita Levi-Montalcini in conjunction with Viktor Hamburger and Hertha Meyer and published in Cancer Research in 1954. In this series of experiments, conducted at the University of Brazil, Levi-Montalcini demonstrated increased nerve growth by introducing specific tumors (sarcomas) to chick ganglia. Ganglia are clusters of nerve cells, from which nerve fibers emerge.
Format: Articles
Subject: Experiments
The Magdalene Sisters (2002)
In 2002, Miramax Entertainment released The Magdalene Sisters, a film that portrays an interpretation of the true events experienced by four young women who were forcibly placed into a Magdalene asylum in Dublin, Ireland, in 1964. Catholic nuns ran Magdalene asylums throughout the world, where they forced women whom society deemed sexually promiscuous to perform hard labor in their laundry facilities. The film portrays the experiences of four women, Margaret, Bernadette, Rose, and Crispina, as they experienced negative treatment from the nuns and sought escape.
Format: Articles
Subject: Outreach
"Versuche zur Analyse der Induktionsmittel in der Embryonalentwicklung" (1932), by Hermann Bautzmann, Johannes Holtfreter, Otto Mangold, and Hans Spemann
In "Versuche zur Analyse der Induktionsmittel in der Embryonalentwicklung," published in Naturwissenschaften in 1932, Hermann Bautzmann, Johannes Holtfreter, Otto Mangold, and Hans Spemann jointly reported on experiments each had conducted testing the activity of organizers killed by boiling, freezing, alcohol, and drying. Each of the authors had been independently conducting similar experiments, when Holtfreter made a breakthrough allowing him to produce many more successful transplantations.
Format: Articles
Subject: Experiments
Viktor Hamburger (1900-2001)
Viktor Hamburger was an embryologist who focused on neural development. His scientific career stretched from the early 1920s as a student of Hans Spemann to the late 1980s at Washington University resolving the role of nerve growth factor in the life of neurons. Hamburger is noted for his systematic approach to science and a strict attention to detail. Throughout his life he maintained an interest in nature and the arts, believing both were important to his scientific work.
Format: Articles
Subject: People