Search

Displaying 326 - 350 of 580 items.

Johann Gregor Mendel (1822-1884)

Johann Gregor Mendel studied plants and their patterns of inheritance in Austria during the nineteenth century. Mendel experimented with the pea plant, Pisum, and his publication, 'Versuche uber Pflanzenhybriden' (“Experiments on Plant Hybridization”), published in 1866, revolutionized theories of trait inheritance. Mendel’s discoveries relating to factors, traits, and how they pass between generations of organisms enabled scientists in the twentieth century to build theories of genetics.

Format: Articles

Subject: People

Johannes Holtfreter (1901-1992)

Johannes Holtfreter made important discoveries about the properties of the organizer discovered by Hans Spemann. Although he spent much time away from the lab over many years, he was a productive researcher. His colleagues noted that the time he spent away helped revitalize his ideas. He is credited with the development of a balanced salt medium to allow embryos to develop; the discovery that dead organizer tissue retains inductive abilities; and the development of specification, competence, and distribution of fate maps in the developing frog embryo.

Format: Articles

Subject: People

Lennart Nilsson (1922- )

Lennart Nilsson is a world-renowned photojournalist recognized for his exploratory images of the inside of the human body. Throughout his career, Nilsson has received a great deal of publicity for his images documenting the human reproductive system and the morphology of viruses. His photography was the first to capture early human development and the developmental stages of embryos and fetuses. These images have helped shape the way the public visualizes development.

Format: Articles

Subject: People, Outreach, Reproduction

Florence Rena Sabin (1871-1953)

Florence Rena Sabin had successful careers as both a researcher and public health reformer. When Johns Hopkins University Medical School opened, accepting women and men on the same basis, Sabin was one of the first to enter. After the successful completion of her MD degree, Sabin went on to become the first female faculty member and later full-time professor at Johns Hopkins.

Format: Articles

Subject: People

Warren Harmon Lewis (1870-1964)

As one of the first to work at the Carnegie Institution of Washington Department of Embryology, Warren Harmon Lewis made a number of contributions to the field of embryology. In addition to his experimental discoveries on muscle development and the eye, Lewis also published and revised numerous works of scientific literature, including papers in the Carnegie Contributions to Embryology and five editions of Gray's Anatomy.

Format: Articles

Subject: People

The French Flag Model

The French flag model represents how embryonic cells receive and respond to genetic information and subsequently differentiate into patterns. Created by Lewis Wolpert in the late 1960s, the model uses the French tricolor flag as visual representation to explain how embryonic cells can interpret genetic code to create the same pattern even when certain pieces of the embryo are removed. Wolpert's model has provided crucial theoretical framework for investigating universal mechanisms of pattern formation during development.

Format: Articles

Subject: Processes, Theories

Carnegie Stages

Historically the exact age of human embryo specimens has long perplexed embryologists. With the menstrual history of the mother often unknown or not exact, and the premenstrual and postmenstrual phases varying considerably among women, age sometimes came down to a best guess based on the weight and size of the embryo. Wilhelm His was one of the first to write comparative descriptions of human embryos in the late 1800s. Soon afterward, Franklin P. Mall, the first director of the Carnegie Institution of Washington's (CIW) Department of Embryology, expanded upon His' work.

Format: Articles

Subject: Theories

Martin Couney and Incubator Exhibits from 1896 to 1943

During the late 1800s and early 1900s, physician Martin Couney held incubator exhibits to demonstrate the efficacy of infant incubators throughout the US and
Europe. At his exhibits, Couney demonstrated that isolating premature infants in an incubator ward
could significantly decrease premature infant mortality and increased the use of incubators in the
US.

Format: Articles

Subject: Organizations, Places

Roberto Caldeyro-Barcia (1921–1996)

Roberto Caldeyro-Barcia studied fetal health in Uruguay during the second half of the twentieth century. Caldeyro-Barcia developed Montevideo units, which are used to quantify intrauterine pressure, or the force of contractions during labor. Intrauterine pressure is a useful measure of the progression of labor and the health of a fetus.

Format: Articles

Subject: People

Hans Asperger (1906-1980)

Hans Asperger studied mental abnormalities in children in
Vienna, Austria, in the early twentieth century. Asperger was one of
the early researchers who studied the syndrome that was later named
after him, Asperger's Syndrome. Asperger described the syndrome in
his 1944 publication Die Autistischen Psychopathen im
Kindesalter (Autistic Psychopathy in Childhood). At that time,
the syndrome was called autistic psychopathy, and Asperger noted
that characteristics of the syndrome included lack of sympathy,

Format: Articles

Subject: People

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

Evangelium Vitae (1995), by Pope John Paul II

The encyclical entitled "Evangelium Vitae," meaning "The Gospel of Life," was promulgated on 25 March 1995 by Pope John Paul II in Rome, Italy. The document was written to reiterate the view of the Roman Catholic Church on the value of life and to warn against violating the sanctity of life. The document focuses on right to life issues including abortion, birth control, and euthanasia, but also touches on other concepts relevant to embryology, such as contraception, in vitro fertilization, sterilization, embryonic stem cell research, and fetal experimentation.

Format: Articles

Subject: Religion, Reproduction

James Alexander Thomson (1958- )

James Alexander Thomson, affectionately known as Jamie Thomson, is an American developmental biologist whose pioneering work in isolating and culturing non-human primate and human embryonic stem cells has made him one of the most prominent scientists in stem cell research. While growing up in Oak Park, Illinois, Thomson's rocket-scientist uncle inspired him to pursue science as a career. Born on 20 December 1958, Thomson entered the nearby University of Illinois Urbana-Champaign nineteen years later as a National Merit Scholar majoring in biophysics.

Format: Articles

Subject: People

Hysterectomy

A hysterectomy is the surgical removal of a woman's uterus. For many women, a hysterectomy comes as a solution to health problems as diverse as abnormal bleeding to reproductive cancers. First performed in the early 1800s, this procedure has evolved in terms of both technique and popularity. The first successful abdominal hysterectomy was performed by Ellis Burnham in Lowell, Massachusetts, in 1853, although earlier attempts were made in the 1840s.

Format: Articles

Subject: Technologies, Reproduction

VACTERL Association

VACTERL association is a term applied to a specific group of abnormalities involving structures derived from the mesoderm. Although the defects of this disorder are clearly linked, VACTERL is called an association rather than a syndrome because the exact genetic cause is unknown. "VACTERL" is an acronym, each letter standing for one of the defects associated with the condition: V for vertebral anomalies, A for anal atresia, C for cardiovascular anomalies, T for tracheoesophageal fistula, E for esophageal atresia, R for renal anomalies, and L for limb defects.

Format: Articles

Subject: Disorders

Tissue Engineering

Tissue engineering is a field of regenerative medicine that integrates the knowledge of scientists, physicians, and engineers into the construction or reconstruction of human tissue. Practitioners of tissue engineering seek to repair, replace, maintain, and enhance the abilities of a specific tissue or organ by means of living cells. More often than not stem cells are the form of living cells used in this technology. Tissue engineering is one of the disciplines involved in translating knowledge of developmental biology into the clinical setting.

Format: Articles

Subject: Processes

"Visualizing Human Embryos" (1999), by Bradley Richard Smith

In March 1999 Bradley Richard Smith, a professor at the University of Michigan, unveiled the first digital magnetic resonance images of human embryos. In his article "Visualizing Human Embryos for Scientific American," Smith displayed three-dimensional images of embryos using combinations of Magnetic Resonance Microscopy (MRM), light microscopy, and various computer editing. He created virtual embryo models that it is possible to view as dissections, animations, or in their whole 3D form. Smith's images constitute a new way of visualizing embryos.

Format: Articles

Subject: Outreach, Publications

Embryonic Sex Differentiation and Sex Hormones (1947), by Carl R. Moore

In 1947, Carl Richard Moore, a researcher at the University of Chicago, in Chicago, Illinois, wrote Embryonic Sex Differentiation and Sex Hormones, which was published in the same year as a first-edition monograph. In the book, Moore argues that regulation of sex differentiation in mammals is not controlled by sex hormones secreted by embryonic sex organs (gonads), but is controlled by non-hormonal genetic factors.

Format: Articles

Subject: Publications, Experiments

The Milky Way (2014)

On 26 April 2014, Gravitas Ventures released the documentary The Milky Way, a film directed by Jon Fitzgerald that compares breastfeeding in the US with breastfeeding in European countries. The film was produced by Piece of My Heart Productions and Cause Pictures. In the film, producers Jennifer Davidson and Chantal Molnar travel to Berlin, Germany, and Stockholm, Sweden, to observe how people perceive breastfeeding there, compared to in the US.

Format: Articles

Subject: Outreach

De Monstruorum Causis, Natura et Differentiis (On the Reasons, Nature and Differences of Monsters) (1616), by Fortunio Liceti

In 1616 in Padua, Italy, Fortunio Liceti, a professor of natural philosophy and medicine, wrote and published the first edition of De Monstruorum Causis, Natura et Differentiis (On the Reasons, Nature, and Differences of Monsters), hereafter De monstruorum. In De monstruorum, Liceti chronologically documented cases of human and animal monsters from antiquity to the seventeenth century. During the seventeenth century, many people considered such monsters as frightening signs of evil cursed by spiritual or supernatural entities.

Format: Articles

Subject: Theories

Julia Barlow Platt (1857-1935)

Julia Barlow Platt studied neural crests in animal embryos and became involved in politics in the US during the nineteenth and twentieth centuries. She researched how body and head segments formed in chicks (Gallus gallus) and spiny dogfish (Squalus acanthias). Platt observed that in the mudpuppy (Necturus maculosus), the coordinated migration of neural crest cells in the embryo produced parts of the nervous system, bones, and connective tissues in the head.

Format: Articles

Subject: People

Clinical Tests of Estrogen Injections on Women with Abnormal Menstrual Cycles During the Early 1920s by Jean Paul Pratt and Edgar Allen

In the early twentieth century US, Jean Paul Pratt and Edgar Allen conducted clinical experiments on women who had abnormal menstrual cycles. During the clinical tests, researchers injected the hormone estrogen into their patients to alleviate their menstrual ailments, which ranged from irregular cycles to natural menopause. The hormone estrogen plays a prominent role in the menstrual cycle by signaling the tissue lining the uterus (endometrium) to thicken in preparation for possible pregnancy.

Format: Articles

Subject: Experiments

"Evolution and Tinkering" (1977), by Francois Jacob

In his essay Evolution and Tinkering, published in
Science in 1977, Francois Jacob argued that a common analogy
between the process of evolution by natural selection and the
methods of engineering is problematic. Instead, he proposed to
describe the process of evolution with the concept of
bricolage (tinkering). In this essay, Jacob did not deny the
importance of the mechanism of natural selection in shaping complex
adaptations. Instead, he maintained that the cumulative effects of

Format: Articles

Subject: Publications, Theories

Embryos in Wax (2002), by Nick Hopwood

Embryos in Wax: Models from the Ziegler Studio is a history of embryo wax modeling written by science historian Nick Hopwood. Published by the Whipple Museum of the History of Science University of Cambridge and the Institute of the History of Medicine University of Bern, 2002, the book, like the wax models, helps exemplify the visual and material culture of science.

Format: Articles

Subject: Publications

Jan Swammerdam (1637-1680)

Jan Swammerdam, known as the founder of the preformation theory based on his extensive research on insect development, was born on 12 February 1637 in Amsterdam, the Netherlands, to Baertje Jans Corvers and Jan Jacobszoon Swammerdam. He began medical school on 11 October 1661 at the University of Leiden. A few of his classmates included Regnier de Graaf, Frederik Ruysch, Niels Stensen (Nicolaus Steno), and Robertus Padtbrugge. Padtbrugge would later join the East India Company and send Swammerdam exotic animals.

Format: Articles

Subject: People