Embryo Project Encyclopedia Articles

Samuel Randall Detwiler was an embryologist who studied neural development in embryos and vertebrate retinas. He discovered evidence for the relationship between somites and spinal ganglia, that transplanted limbs can be controlled by foreign ganglia, and the plasticity of ganglia in response to limb transplantations. He also extensively studied vertebrate retinas during and after embryonic development. Detwiler's work established many principles studied in later limb transplantation experiments and was identified by Viktor Hamburger as an important bridge between his and Ross Granville Harrison's research.

Leonard Colebrook was a physician who researched bacteria and infections in England during the twentieth century. In 1936, Colebrook deployed the antibiotic Prontosil to treat puerperal fever, a disorder that results from bacterial infections in the uterine tracts of women after childbirth or abortions. Colebrook also advanced care for burn patients by advocating for the creation of burn units in hospitals and by using antisepsis medication for burn wound infections. Colebrook’s work on treatments for puerperal fever reduced cases of puerperal fever throughout the world.

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. Those measurements enable physicians to evaluate the progression of labor and intervene when contractions are too weak to properly dilate a laboring woman’s cervix to successfully deliver a fetus. Though IUPCs are not used routinely, they are important in cases where external fetal monitoring is not sufficient to monitor a difficult labor. Intrauterine pressure catheters give physicians an extremely accurate measurement of intrauterine pressure, making it possible to determine whether intervention is needed to progress the labor.

In 1955, obstetrician Edward Bishop, a physician specializing in childbirth, published the article “Elective Induction of Labor,” in which he proposed the best conditions for pregnant women to elect to induce, or begin, labor. Elective induction of labor requires an obstetrician to administer a drug to help a pregnant woman to start her contractions, and to rupture the fluid-filled sac surrounding the fetus called the amniotic sac. In the early 1950s, Bishop analyzed the results of one thousand elective inductions and discovered that some pregnant women had faster and easier deliveries with induced labor than other pregnant women. In “Elective Induction of Labor,” Bishop describes the characteristics an obstetrician can look for in a pregnant woman to determine if she can safely undergo an elective induction, metrics still used into the twenty-first century to determine whether or not to pursue elective inductions.

In 2011, Sonja Vernes and Simon Fisher performed a series of experiments to determine which developmental processes are controlled by the mouse protein Foxp2. Previous research showed that altering the Foxp2 protein changed how neurons grew, so Vernes and Fisher hypothesized that Foxp2 would affect gene networks that involved in the development of neurons, or nerve cells. Their results confirmed that Foxp2 affected the development of gene networks involved in the growth of neurons, as well as networks that are involved in cell specialization and cell communication. The researchers determined that Foxp2 is important for a variety of developmental processes such as motor control, language acquisition, and cognition.

Camillo Golgi studied the central nervous system during the late nineteenth and early twentieth centuries in Italy, and he developed a staining technique to visualize brain cells. Called the black reaction, Golgi’s staining technique enabled him to see the cellular structure of brain cells, called neurons, with much greater precision. Golgi also used the black reaction to identify structures within animal cells like the internal reticular apparatus that stores, packs, and modifies proteins, later named the Golgi apparatus in his honor. Golgi, along with Santiago Ramón y Cajal, received the Nobel Peace Prize in 1906 for their independent work on the structure of the nervous system. Golgi’s discovery of the black reaction enabled other scientists to better study the structure of the nervous system and its development.

In the 1964 article, “Pelvic Scoring for Elective Induction,” obstetrician Edward Bishop describes his method to determine whether a doctor should induce labor, or artificially start the birthing process, in a pregnant woman. Aside from medical emergencies, a woman can elect to induce labor to choose when she gives birth and have a shorter than normal labor. The 1964 publication followed an earlier article by Bishop, also about elective induction. In both articles, Bishop used data gathered from the obstetrics department of Pennsylvania Hospital in Philadelphia, Pennsylvania, where he worked. In “Pelvic Scoring for Elective Induction,” Bishop introduces a scoring system later known as the Bishop Score, used into the twenty-first century, to determine if a pregnant woman fits the criteria for a safe and successful induction.

Scientists use cerebral organoids, which are artificially produced miniature organs that represent embryonic or fetal brains and have many properties similar to them, to help them study developmental disorders like microcephaly. In human embryos, cerebral tissue in the form of neuroectoderm appears within the first nine weeks of human development, and it gives rise to the brain and spinal cord. In the twenty-first century, Juergen Knoblich and Madeleine Lancaster at the Institute of Molecular Biotechnology in Vienna, Austria, grew cerebral organoids from pluripotent stem cells as a model to study developmental disorders in embryonic and fetal brains. One such disorder is microcephaly, a condition in which brain size and the number of neurons in the brain are abnormally small. Scientists use cerebral organoids, which they've grown in labs, because they provide a manipulable model for studying how neural cells migrate during development, the timing of neural development, and how genetic errors can result in developmental disorders.

Virginia Apgar and colleagues wrote “Evaluation of the Newborn Infant—Second Report” in 1958. This article explained that Apgar’s system for evaluating infants’ condition after birth accurately predicted the health of infants. Apgar had developed the scoring system in 1953 to provide a simple method for determining if an infant needed medical attention after birth. The research team, working at Columbia University College of Physicians and Surgeons in New York City, New York, studied the Apgar scores of over 15,000 infants from Sloane Hospital for Women in New York City, New York, over a period of five years. In “Evaluation of the Newborn Infant—Second Report,” Apgar and colleagues established that Apgar scores correlated with infants’ health directly after birth and indicated when medical personnel should treat the infant.

Apoptosis, or programmed cell death, is a mechanism in embryonic development that occurs naturally in organisms. Apoptosis is a different process from cell necrosis, which is uncontrolled cell death usually after infection or specific trauma. As cells rapidly proliferate during development, some of them undergo apoptosis, which is necessary for many stages in development, including neural development, reduction in egg cells (oocytes) at birth, as well as the shaping of fingers and vestigial organs in humans and other animals. Sydney Brenner, H. Robert Horvitz, and John E. Sulston received the Nobel Prize in Physiology or Medicine in 2002 for their work on the genetic regulation of organ development and programmed cell death. Research on cell lineages before and after embryonic development may lead to new ways to reduce or promote cell death, which can be important in preventing diseases such as Alzheimer's or cancer.