Search

Displaying 851 - 866 of 866 items.

Roger Wolcott Sperry (1913–1994)

Roger Wolcott Sperry
studied the function of the nervous system in the US during the
twentieth century. He studied split-brain patterns in cats and
humans that result from separating the two hemispheres of the
brain by cutting the corpus callosum, the bridge between the two
hemispheres of the brain. He found that separating the corpus
callosum the two hemispheres of the brain could not communicate
and they performed functions as if the other hemisphere did not

Format: Articles

Subject: People

Elizabeth Dexter Hay (1927–2007)

Elizabeth Dexter Hay studied the cellular processes that affect development of embryos in the US during the mid-twentieth and early twenty-first centuries. In 1974, Hay showed that the extracellular matrix, a collection of structural molecules that surround cells, influences cell behavior. Cell growth, cell migration, and gene expression are influenced by the interaction between cells and their extracellular matrix.

Format: Articles

Subject: People

“Kangaroo Mother Care to Reduce Morbidity and Mortality in Low Birthweight Infants” (2016), by Agustin Conde-Agudelo and José Díaz-Rossello

In 2016, physician researchers Agustin Conde-Agudelo and José Díaz-Rossello published “Kangaroo Mother Care to Reduce Morbidity and Mortality in Low Birthweight Infants,” in which they compared the effectiveness of Kangaroo Mother Care to that of traditional treatments for low birth weight newborns. Physicians began using Kangaroo Mother Care in the 1970s as a treatment for low birth weight infants. The treatment, which involves exclusive breastfeeding and skin-to-skin contact, was created to help mothers care for low birth weight infants in developing.

Format: Articles

Subject: Publications

Elizabeth Blackwell (1821–1910)

In the nineteenth century, Elizabeth Blackwell was a women’s healthcare reformer and the first woman to receive her medical degree in the United States. She practiced medicine as a primary care physician in both the United States and the United Kingdom. Blackwell graduated medical school from Geneva Medical College in Geneva, New York, where she was the first woman to receive a medical degree in the US.

Format: Articles

Subject: People

The Origin of Species: "Chapter Thirteen: Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs" (1859), by Charles R. Darwin

Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs is the thirteenth chapter of Charles Darwin's book The Origin of Species, first published in England in 1859. The book details part of Darwin's argument for the common ancestry of life and natural selection as the cause of speciation. In this chapter, Darwin summarizes the evidence for evolution by connecting observations of development in organisms to the processes of natural selection.

Format: Articles

Subject: Publications

A History of Embryology (1959), by Joseph Needham

In 1931 embryologist and historian Joseph Needham published a well-received three-volume treatise titled Chemical Embryology. The first four chapters from this work were delivered as lectures on Speculation, Observation, and Experiment, as Illustrated by the History of Embryology at the University of London. The same lectures were later released as a book published in 1934 titled A History of Embryology.

Format: Articles

Subject: Publications

William Thomas Astbury (1898–1961)

William Thomas Astbury studied the structures of fibrous materials, including fabrics, proteins, and deoxyribonucleic acid, or DNA, in England during the twentieth century. Astbury employed X-ray crystallography, a technique in which scientists use X-rays to learn about the molecular structures of materials. Astbury worked at a time when scientists had not yet identified DNA’s structure or function in genes, the genetic components responsible for how organisms develop and reproduce. He was one of the first scientists to use X-ray crystallography to study the structure of DNA.

Format: Articles

Subject: People

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

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

Endoderm

Endoderm is one of the germ layers-- aggregates of cells that organize early during embryonic life and from which all organs and tissues develop. All animals, with the exception of sponges, form either two or three germ layers through a process known as gastrulation. During gastrulation, a ball of cells transforms into a two-layered embryo made of an inner layer of endoderm and an outer layer of ectoderm. In more complex organisms, like vertebrates, these two primary germ layers interact to give rise to a third germ layer, called mesoderm.

Format: Articles

Subject: Processes

Ectoderm

Ectoderm is one of three germ layers--groups of cells that coalesce early during the embryonic life of all animals except maybe sponges, and from which organs and tissues form. As an embryo develops, a single fertilized cell progresses through multiple rounds of cell division. Eventually, the clump of cells goes through a stage called gastrulation, during which the embryo reorganizes itself into the three germ layers: endoderm, ectoderm, and mesoderm. After gastrulation, the embryo goes through a process called neurulation, which starts the development of nervous system.

Format: Articles

Subject: Processes

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

John Chassar Moir (1900–1977)

John Chassar Moir lived in Scotland during the twentieth century and helped develop techniques to improve the health of pregnant women. Moir helped to discover compounds that doctors could administer to women after childbirth to prevent life-threatening blood loss. Those compounds included the ergot alkaloid called ergometrine, also called ergonovine, and d-lysergic acid beta-propanolamide. Moir tested ergometrine in postpartum patients and documented that it helped prevent or manage postpartum hemorrhage in women.

Format: Articles

Subject: People, Reproduction, Disorders

"Health Status of Vietnam Veterans III. Reproductive Outcomes and Child Health" (1988), by the US Centers for Disease Control

In 1988, the US Centers for Disease Control published 'Health Status of Vietnam Veterans III. Reproductive Outcomes and Child Health,' which summarized part of the results of the Vietnam Experience Study commissioned by US Congress to assess the health of US Vietnam veterans. They published the article in the Journal of the American Medical Association. The most heavily used herbicide in the Vietnam, Agent Orange, had previously been found to contain a contaminant linked to birth defects in rats.

Format: Articles

Subject: Publications

William Stewart Halsted (1852-1922)

William Stewart Halsted was a surgeon at Johns Hopkins Hospital in Baltimore, Maryland, during the late 1800s and early 1900s. In 1894 Halsted described his procedure for treating breast cancer by removing the breast tissue, chest muscles, and lymph nodes in the armpit, a procedure he named radical mastectomy, and that became the standard of care for treating breast cancer until 1970.

Format: Articles

Subject: People