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Nuclear Transplantation

Nuclear transplantation is a method in which the nucleus of a donor cell is relocated to a target cell that has had its nucleus removed (enucleated). Nuclear transplantation has allowed experimental embryologists to manipulate the development of an organism and to study the potential of the nucleus to direct development. Nuclear transplantation, as it was first called, was later referred to as somatic nuclear transfer or cloning.

Format: Articles

Subject: Processes

Hematopoietic Stem Cell Transplantation

The purpose of regenerative medicine, especially tissue engineering, is to replace damaged tissue with new tissue that will allow the body to resume normal function. The uniqueness of tissue engineering is that it can restore normal structure in addition to repairing tissue function, and is often accomplished using stem cells. The first type of tissue engineering using stem cells was hematopoietic stem cell transplantation (HSCT), a surgical procedure in which hematopoietic stem cells (HSCs) are infused into a host to treat a variety of blood diseases, cancers, and immunodeficiencies.

Format: Articles

Subject: Technologies

Petr Alekseevich Kropotkin (1842-1921)

Petr Kropotkin proposed the theory of Pleistocene ice age, alternative theories of evolution based on embryology, and he advocated anarchist and communist social doctrines in Europe during the nineteenth and twentieth centuries. He traveled in eastern Siberia and Manchuria from 1863 until 1867, and his subsequent publications about that area's geography became authoritative until the middle of the twentieth century.

Format: Articles

Subject: People

The Dalkon Shield

The Dalkon Shield was an intrauterine contraceptive device (IUD) that women used in the early 1970s and 1980s. Produced by the A.H. Robins Company in the US, the Dalkon Shield was a contraceptive device placed directly into a woman’s uterus that was supposed to prevent the development of a fetus in the uterus. In the 1980s, researchers uncovered an array of severe birth defects and injuries caused by the Dalkon shield, including pelvic infection, infertility, and death of the user. Eventually the A.H.

Format: Articles

Subject: Technologies

The Hedgehog Signaling Pathway in Vertebrates 

The hedgehog signaling pathway is a mechanism that regulates cell growth and differentiation during embryonic development, called embryogenesis, in animals. The hedgehog signaling pathway works both between cells and within individual cells.

Format: Articles

Subject: Theories

Mary-Claire King (1946– )

Mary-Claire King studied genetics in the US in the twenty-first century. King identified two genes associated with the occurrence of breast cancer, breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2). King showed that mutated BRCA1 and BRCA2 genes cause two types of reproductive cancer, breast and ovarian cancer. Because of King’s discovery, doctors can screen women for the inheritance of mutated BRCA1 and BRCA2 genes to evaluate their risks for breast and ovarian cancer.

Format: Articles

Subject: People

William Withey Gull (1816-1890)

William Withey Gull studied paraplegia, anorexia, and hormones as a physician in England during the nineteenth century. In addition to caring for patients, he described the role of the posterior column of the spinal cord in paraplegia, and he was among the first to describe the conditions of anorexia and of hypochondria. He also researched the effects of thyroid hormone deficiencies in women who had malfunctioning thyroid glands.

Format: Articles

Subject: People

Endoscopy

Endoscopy is a medical procedure that enables the viewing and biopsy of, and surgery on, internal tissues and organs. Endoscopic examinations are characterized by the introduction of a tube containing a series of lenses into the body through either an incision in the skin or a natural opening or cavity. During the mid-twentieth century, photographer Lennart Nilsson used endoscopes to capture the now-familiar images of embryos and fetuses.

Format: Articles

Subject: Technologies, Reproduction

Commonwealth v. Luceba Parker [Brief] (1845)

The Court settled the question left open from the case of Commonwealth v. Bangs that it must be proved a woman was "quick with child" in order for abortion prohibitions to have any effect in Massachusetts.

Format: Articles

Subject: Legal, Reproduction

Wilhelm August Oscar Hertwig (1849-1922)

Wilhelm August Oscar Hertwig contributed to embryology through his studies of cells in development and his discovery that only one spermatozoon is necessary to fertilize an egg. He was born 21 April 1849 to Elise Trapp and Carl Hertwig in Hessen, Germany. After his brother Richard was born the family moved to Muhlhausen in Thuringen where the boys were educated. The two brothers later attended the university in Jena from 1868 to 1888 and studied under Ernst Haeckel, who later convinced Hertwig to leave chemistry and pursue medicine.

Format: Articles

Subject: People

Pope Sixtus V (1520-1590)

Known for dropping a long-held distinction in the Catholic Church between the animated and unanimated fetus, Felice Peretti was born in Grottamare, Italy, in 1521, son of a Dalmatian gardener. In his early years, Peretti worked as a swineherd, but soon became involved in the local Minorite convent in Montalto, where he served as a novice at the age of twelve. He went on to study in Montalto, Ferrara, and Bologna, continuing his devotion to religious life, and in 1547 Peretti was ordained as priest in the city of Siena.

Format: Articles

Subject: People, Religion, Reproduction

"Effraenatam" (1588), by Pope Sixtus V

"Effraenatam," the brain-child of Pope Sixtus V, was released as a papal bull in the year 1588. Papal bulls are formal declarations issued by the pope of the Roman Catholic Church and are named for their authenticating leaden seals (bullas). This particular document became famous for its official forbiddance of all procured abortions. "Effraenatam," meaning "without restraint," is often regarded as a specific response to increasing rates of prostitution and procured abortions in the Papal States, though this is not discussed in the actual document.

Format: Articles

Subject: Religion, Reproduction

Susceptibility Assay

Charles Manning Child designed an experimental test, the susceptibility assay, to measure the effects of different toxins on developmental processes. The susceptibility assay measured an organism s vulnerability to death when it was submerged in a noxious solution. The assay involved immersing an organism in a solution that contained a depressant or inhibitory substance, such as alcohol, and then measuring the responses of the organism. Child interpreted these measurements as revealing information about the relative levels of metabolic activity within the organism.

Format: Articles

Subject: Technologies

Humanae Vitae (1968), by Pope Paul VI

The "Humanae Vitae," meaning "Of Human Life" and subtitled "On the Regulation of Birth," was an encyclical promulgated in Rome, Italy, on 25 July 1968 by Pope Paul VI. This encyclical defended and reiterated the Roman Catholic Church's stance on family planning and reproductive issues such as abortion, sterilization, and contraception. The document continues to have a controversial reputation today, as its statements regarding birth control strike many Catholics as unreasonable.

Format: Articles

Subject: Religion, Reproduction

Ross Granville Harrison (1870-1959)

A pioneer in experimental embryology, Ross Granville Harrison made numerous discoveries that advanced biology. One of the most significant was his adaptation of the hanging drop method from bacteriology to carry out the first tissue culture. This method allowed for further studies in embryology as well as experimental improvements in oncology, virology, genetics, and a number of other fields.

Format: Articles

Subject: People

Hedgehog Signaling Pathway

The hedgehog signaling pathway is a mechanism that directs the development of embryonic cells in animals, from invertebrates to vertebrates. The hedgehog signaling pathway is a system of genes and gene products, mostly proteins, that convert one kind of signal into another, called transduction. In 1980, Christiane Nusslein-Volhard and Eric F. Wieschaus, at the European Molecular Biology Laboratory in Heidelberg, Germany, identified several fruit fly (Drosophila melanogaster) genes.

Format: Articles

Subject: Processes

Theodora (Theo) Emily Colborn (1927-2014)

Theodora Colborn studied how chemicals affect organisms as they develop and reproduce during the twentieth and twenty first centuries in the US. By the 1940s, researchers had reported that chemicals from agricultural and industrial processes affected how wild organisms developed, but in 1991, Colborn organized the Wingspread Conference in Racine, Wisconsin, at which a group of scientists classed these chemicals as environmentally harmful substances. Colborn and her colleagues called those chemicals endocrine disruptors, as they mimic or block the body's endocrine system.

Format: Articles

Subject: People

The Interpretation of Development and Heredity (1930), by Edward Stuart Russell

First published in 1930 and reprinted in 1972, Edward Stuart Russell's The Interpretation of Development and Heredity is a work of philosophical and theoretical biology. In this book Russell outlines a methodological and philosophical program aimed at reorienting the biological understanding of development and heredity.

Format: Articles

Subject: Publications

Arthur Earl Walker (1907-1995)

Arthur Earl Walker was a medical researcher and physician who studied the brain and neurosurgery in the United States during the twentieth century. Walker examined the connections of the thalamus to the rest of the brain and how the thalamus coordinates sensory signals. The thalamus is a cluster of nerve cells located between the two hemispheres of the brain and it is responsible for consciousness and sensory interpretation.

Format: Articles

Subject: People

Exchange Transfusion for Jaundiced Newborns in the United States

Exchange transfusion is the replacement of blood from newborn infants with elevated bilirubin level in their blood stream with donor blood containing normal bilirubin levels. Newborn infants that experience jaundice, the yellowing of the skin and eyes, have a buildup of bilirubin, a chemical that occurs during red blood cell breakdown, or hemolysis. Exchange transfusion is a therapy developed throughout the 1940s by Louis Diamond and a group of surgeons at the Children’s Medical Center in Boston, Massachusetts.

Format: Articles

Subject: Technologies

Martius Flap Procedure to Repair Obstetric Fistulas

The Martius flap procedure is a surgical procedure used to treat obstetric fistulas in women. Heinrich Martius developed the procedure in twentieth century Germany to treat women with urinary incontinence caused by stress, and later doctors used it to repair obstetric fistulas. Fistulas occur in pregnant women when a hole is torn between the vagina and the urinary tract (called vesicovaginal) or the vagina and the rectum (called rectovaginal). The hole, or fistula, occurs in the tissue separating two organs and therefore obstetric fistulas result in either urinary or fecal incontinence.

Format: Articles

Subject: Technologies, Disorders

Nettie Maria Stevens (1861-1912)

Multiple theories about what determines sex were tested at the turn of the twentieth century. By experimenting on germ cells, cytologist Nettie Maria Stevens collected evidence to support the connection between heredity and the sex of offspring. Stevens was able to interpret her data to conclude that chromosomes have a role in sex determination during development. For her time, she was an emerging breed: a woman of science making the leap from the world of data collection to that of male-dominated interpretive work.

Format: Articles

Subject: People, Reproduction

Robert William Briggs (1911-1983)

Robert William Briggs was a prolific developmental biologist. However, he is most identified with the first successful cloning of a frog by nuclear transplantation. His later studies focused on the problem of how genes influence development.

Format: Articles

Subject: People

The Source-Sink Model

The source-sink model, first proposed by biologist Francis Crick in 1970, is a theoretical system for how morphogens distribute themselves across small fields of early embryonic cells. A morphogen is a substance that determines the fate and phenotype of a group of cells through a concentration gradient of itself across that group. Crick’s theory has been experimentally confirmed with several morphogens, most notably with the protein bicoid , the first discovered morphogen. The model provides a theoretical structure for the understanding of some features of early embryonic development.

Format: Articles

Subject: Theories

Edwin Grant Conklin (1863-1952)

Edwin Grant Conklin was born in Waldo, Ohio, on 24 November 1863 to parents Nancy Maria Hull and Dr. Abram V. Conklin. Conklin's family was very religious and he seriously considered a theistic path before choosing a career in academics. Conklin's scientific work was primarily in the areas of embryology, cytology, and morphology, though many questions regarding the relationships between science, society, and philosophy had an influence on both his writings and academic lectures.

Format: Articles

Subject: People