Julia Barlow Platt's Embryological Observations on Salamanders' Cartilage (1893)

Julia Barlow Platt's Embryological Observations on Salamanders' Cartilage (1893)In 1893, Julia Barlow Platt published her research on the origins of cartilage in the developing head of the common mudpuppy (Necturus maculosus) embryo. The mudpuppy is an aquatic salamander commonly used by embryologists because its large embryonic cells and nuclei are easy to see. Platt followed the paths of cells in developing mudpuppy embryos to see how embryonic cells migrated during the formation of the head. With her research, Platt challenged then current theories about germ layers, the types of cells in an early embryo that develop into adult cells. In most organisms' development, three types of germ layers are responsible for the formation of tissues and organs. The

Edward Charles Dodds (1899-1973)

Edward <a href="/search?text=Charles%20Dodds" title="" class="lexicon-term">Charles Dodds</a> (1899-1973)Edward Charles Dodds researched the function and effects of natural and artificial hormones on the endocrine system in England during the twentieth century. Though he first worked with hormones such as insulin, Dodds focused on the effects of estrogen in the body and how to replicate those effects with artificial substances. In 1938, along with chemist Robert Robinson, Dodds synthesized the first synthetic estrogen called diethylstilbestrol.

Golgi Staining Technique

Golgi Staining TechniqueThe Golgi staining technique, also called the black reaction after the stain's color, was developed in the 1870s and 1880s in Italy to make brain cells (neurons) visible under the microscope. Camillo Golgi developed the technique while working with nervous tissue, which required Golgi to examine cell structure under the microscope. Golgi improved upon existing methods of staining, enabling scientists to view entire neurons for the first time and changing the way people discussed the development and composition of the brain's cells. Into the twenty-fist century, Golgi's staining method continued to inform research on the nervous system, particularly regarding embryonic development.

Walter Edward Dandy (1886-1946)

Walter Edward Dandy (1886-1946) Walter Edward Dandy studied abnormalities in the developing human brain in the United States in the twentieth century. He collaborated with pediatrician Kenneth Blackfan to provide the first clinical description of Dandy-Walker Syndrome, a congenital brain malformation in which the medial part of the brain, called the cerebellar vermis, is absent. Dandy also described the circulation of cerebral spinal fluid, the clear, watery fluid that surrounds and cushions the brain and spinal cord. That description led Dandy to examine how the impeded flow of cerebral spinal fluid caused congenital hydrocephalus, which occurs when fluid accumulates in the brain causing it to swell. Dandy discovered

Dandy-Walker Syndrome

Dandy-Walker Syndrome Dandy-Walker Syndrome is a congenital brain defect in humans characterized by malformations to the cerebellum, the part of the brain that controls movement, and to the ventricles, the fluid-filled cavities that surround the cerebellum. The syndrome is named after physicians Walter Dandy and Arthur Walker, who described associated signs and symptoms of the syndrome in the 1900s. The malformations often develop during embryonic stages. In early infancy, symptoms include slow motor development and a progressive enlargement of the skull due to cerebrospinal fluid accumulation called hydrocephalus.

Edgar Allen and Edward A. Doisy's Extraction of Estrogen from Ovarian Follicles, (1923)

Edgar Allen and Edward A. Doisy's Extraction of Estrogen from Ovarian Follicles, (1923) In the early 1920s, researchers Edgar Allen and Edward Adelbert Doisy conducted an experiment that demonstrated that ovarian follicles, which produce eggs in mammals, also contain and produce what they called the primary ovarian hormone, later renamed estrogen. In their experiment, Doisy and Allen extracted estrogen from the ovarian follicles of hogs and proved that they had isolated estrogen by using a measurement later renamed the Allen-Doisy test. Allen and

Transposition of the Great Arteries (TGA)

Transposition of the Great Arteries (TGA)Transposition of the great arteries or TGA is a potentially fatal congenital heart malformation where the pulmonary artery and the aorta are switched. The switch means that the aorta, which normally carries oxygenated blood, carries deoxygenated blood. There are two types of the malformation, d-TGA where no oxygen reaches the body and l-TGA where some oxygenated blood circulates. In the US, the Centers for Disease Control estimate that about 1,901 infants are born each year with TGA, or about one for every 2,000 births. Throughout history, physicians classified TGA as a condition that causes blue babies and hypothesized it was a fatal condition. With the development of corrective surgeries, studies on the causes of TGA, and improved prenatal diagnosis have

Karl Oskar Illmensee (1939–)

Karl Oskar Illmensee (1939–) Karl Oskar Illmensee studied the cloning and reproduction of fruit flies, mice, and humans in the US and Europe during the twentieth and twenty-first centuries. Illmensee used nuclear transfer techniques (cloning) to create early mouse embryos from adult mouse cells, a technique biologists used in later decades to help explain how embryonic cells function during development. In the early 1980s, Illmensee faced accusations of fraud when others were unable to replicate the results of his experiments with cloned mouse embryos.

The Effectiveness of Phototherapy in Premature Infants (1968)

The Effectiveness of Phototherapy in Premature Infants (1968) In 1968, pediatric researchers Jerold Lucey, Mario Ferreiro, and Jean Hewitt conducted an experimental trial that determined that exposure to light effectively treated jaundice in premature infants. The three researchers published their results in "Prevention of Hyperbilirubinemia of Prematurity by Phototherapy" that same year in Pediatrics . Jaundice is the yellowing of the skin and eyes due to the failure of the liver to break down excess bilirubin in the blood, a condition called hyperbilirubinemia. Bilirubin is a product that results from the degradation of red blood cells, which the immature liver of premature infants often has difficulty breaking down. Lucey's group's study demonstrated both the efficacy of phototherapy, which uses light to breakdown the

Robert Guthrie (1916–1995)

Robert Guthrie (1916–1995)Robert Guthrie developed a method to test infants for phenylketonuria or PKU in the United States during the twentieth century. PKU is an inherited condition that causes an amino acid called phenylalanine to build to toxic levels in the blood. Untreated, PKU causes mental disabilities. Before Guthrie’s test, physicians rarely tested infants for PKU and struggled to diagnose it. Guthrie’s test enabled newborns to be quickly and cheaply screened at birth and then treated for PKU if necessary, preventing irreversible neurological damage. After developing the test, Guthrie traveled the world to advocate for mass screening for PKU in newborns. Along with his PKU test, Guthrie developed newborn screens for maple syrup urine disease and for galactosemia. Guthrie’s test for PKU and campaign for newborn screening led to the early diagnoses of PKU in thousands of infants, preventing those infants