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Displaying 851 - 875 of 1212 items.

Frederik Ruysch (1638-1731)

Frederik Ruysch made anatomical drawings and collected and preserved human specimens, many of which were infants and fetuses, in the Netherlands during the seventeenth and eighteenth centuries. Ruysch had many interests, including anatomy, botany, and medicine, and he discovered structures of the lymphatic system and of the eye. His collection of preserved human specimens were used as educational tools for his students and for other physicians, and they were displayed in a museum of his own making that was open to the public.

Format: Articles

Subject: People

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

Henry Havelock Ellis (1859-1939)

Henry Havelock Ellis was born on 2 February 1859 at Croydon in Surrey, England, to Susannah Wheatley Ellis and Edward Peppen Ellis, a sea captain. A psychologist, essayist, and physician, he is best known for his contributions to the study of human sexuality and his support of sex education and women's rights. Ellis 's work catalyzed the revolution against repressive Victorian views of sexuality.

Format: Articles

Subject: People

Leonardo da Vinci (1452-1519)

Leonardo da Vinci was born on 15 April 1452, the illegitimate son of a young peasant girl by the name of Caterina and Ser Piero da Vinci, a well-renowned Florentine notary. Leonardo lived in Italy in the town of Vinci until his late teens and received a simple education in reading and writing as well as some training in mathematics and engineering. Although he was socially excluded by birthright from almost every profession and prohibited from attending any formal university, Leonardo went on to become a celebrated scientist, artist, and engineer.

Format: Articles

Subject: People

Assisted Human Reproduction Canada (AHRC)

Established under the Assisted Human Reproduction (AHR) Act of 2004, Assisted Human Reproduction Canada (AHRC), also known as the Assisted Human Reproduction Agency of Canada, was created in 2006 to oversee research related to reproductive technologies and to protect the reproductive rights and interests of Canadian citizens. AHRC serves as a regulatory body for the development and use of such research and technology while enforcing the guidelines and restrictions laid out by the AHR Act.

Format: Articles

Subject: Organizations, Reproduction

Assisted Reproductive Technologies

Assisted reproductive technologies (ART) are a collection of different techniques designed to help those who are infertile achieve a successful pregnancy. The most popular technology currently in use is in vitro fertilization (IVF), but others include gamete intrafallopian transfer (GIFT), zygote intrafallopian transfer (ZIFT), intrauterine insemination (IUI), and intracytoplasmic sperm injection (ICSI).

Format: Articles

Subject: Technologies, Reproduction

The Mechanistic Conception of Life (1912), by Jacques Loeb

Jacques Loeb published The Mechanistic Conception of Life in 1912. Loeb's goal for the book was to further disseminate his explanations of organic processes, such as embryonic development and organisms orientations to their environments, which relied on physics and chemistry. Loeb also wanted to provide an alternative explanatory framework to vitalism and what he called romantic evolutionism, then both widespread.

Format: Articles

Subject: Publications

"Further Experiments on Artificial Parthenogenesis and the Nature of the Process of Fertilization" (1900), by Jacques Loeb

Jacques Loeb broadened and corrected his earlier claims concerning artificial parthenogenesis in sea urchins in a series of experiments in 1900. He published these findings, "Further Experiments on Artificial Parthenogenesis and the Nature of The Process of Fertilization," in a 1900 issue of The American Journal of Physiology.

Format: Articles

Subject: Experiments

The Organism as a Whole: From a Physicochemical Viewpoint (1916), by Jacques Loeb

Jacques Loeb published The Organism as a Whole: From a Physicochemical Viewpoint in 1916. Loeb's goal for the book was to refute the claim that physics and chemistry were powerless to completely explain whole organisms and their seemingly goal-oriented component processes. Loeb used his new account of science and scientific explanation, marshaling evidence from his embryological researches, to show that physicochemical biology completely and correctly explained whole organisms and their component processes.

Format: Articles

Subject: Publications

"A Genomic Regulatory Network for Development" (2002), by Eric H. Davidson, et al.

In 2002 Eric Davidson and his research team published 'A Genomic Regulatory Network for Development' in Science. The authors present the first experimental verification and systemic description of a gene regulatory network. This publication represents the culmination of greater than thirty years of work on gene regulation that began in 1969 with 'A Gene Regulatory Network for Development: A Theory' by Roy Britten and Davidson. The modeling of a large number of interactions in a gene network had not been achieved before.

Format: Articles

Subject: Publications

Johann Friedrich Meckel, the Younger (1781-1833)

Johann Friedrich Meckel studied abnormal animal and human anatomy in nineteenth century Germany in an attempt to explain embryological development. During Meckel's lifetime he catalogued embryonic malformations in multiple treatises. Meckel's focus on malformations led him to develop concepts like primary and secondary malformations, atavism, and recapitulation- all of which influenced the fields of medicine and embryology during the nineteenth and twentieth centuries.

Format: Articles

Subject: People

"The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement" (1910), by Ross Granville Harrison

In "The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement," Ross Granville Harrison explores the growth of nerve fibers in vitro. The purpose of this experiment was to test two possible hypotheses for the growth of nerve fibers. Santiago Ramón y Cajal suggested that nerve growth is due to the extension of nerve fibers as they push through tissue. Victor Hensen's syncytial theory proposed an opposing view of nerve growth.

Format: Articles

Subject: Experiments

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

Otto Mangold (1891-1962)

Otto Mangold was an early twentieth century embryologist who specialized in the development of amphibian embryos. A major emphasis of his research was refining the concept of the organizer, now referred to as embryonic induction. He was born on 4 November 1891 in Auenstein, Germany, and came from what Viktor Hamburger, a colleague and personal acquaintance, described as "peasant stock." Mangold attended several universities including Tübingen, Freiburg, and Rostock.

Format: Articles

Subject: People

Fate Mapping Techniques

For more than 2000 years, embryologists, biologists, and philosophers have studied and detailed the processes that follow fertilization. The fertilized egg proliferates into cells that begin to separate into distinct, identifiable zones that will eventually become adult structures through the process of morphogenesis. As the cells continue to multiply, patterns form and cells begin to differentiate, and eventually commit to their fate.

Format: Articles

Subject: Technologies

James Marion Sims's Treatment of Vesico-Vaginal Fistula

James Marion Sims developed a treatment for vesico-vaginal fistulas in Montgomery, Alabama in the 1840s. Vesico-vaginal fistulas were a relatively common condition in which a woman's urine leaked into her vaginal cavity from her bladder, and many regarded the fistulas as untreatable during the early 1800s. After years of efforts to repair the fistulas with myriad tools, techniques, and procedures, Sims developed the speculum and a vaginal examination position later named for him.

Format: Articles

Subject: Technologies, Reproduction

Elizabeth Maplesden Ramsey (1906-1993)

Physician and pathologist Elizabeth Maplesden Ramsey was a member of the Carnegie Institution of Washington (CIW) for thirty-nine years. The affiliation began in 1934, when Ramsey discovered what was assumed to be the youngest-known embryo at the time, and donated it to CIW's massive embryo collection. After studying embryos, Ramsey focused her research on placental circulation in primates.

Format: Articles

Subject: People

The Game of Life, by John Horton Conway

The Game of Life, or just Life, is a one-person game that was created by the English mathematician John Horton Conway in the late 1960s. It is a simple representation of birth, death, development, and evolution in a population of living organisms, such as bacteria. Martin Gardner popularized the Game of Life by writing two articles for his column "Mathematical Games" in the journal Scientific American in 1970 and 1971. There exist several websites that provide the Game of Life as a download or as an online game.

Format: Articles

Subject: Technologies

Tay-Sachs Disease

In 1881 British opthalmologist Warren Tay made an unusual observation. He reported a cherry-red spot on the retina of a one-year-old patient, a patient who was also showing signs of progressive degeneration of the central nervous system as manifested in the child's physical and mental retardation. This cherry-red spot is a characteristic that would eventually come to be associated with metabolic neurological disorders like Sandhoff, GM-1, Niemann-Pick, and, to the credit of Tay, the lysosomal storage disorder known as Tay-Sachs disease.

Format: Articles

Subject: Disorders

"Experiments on Artificial Parthenogenesis in Annelids (Chaetopterus) and the Nature of the Process of Fertilization" (1901), by Jacques Loeb

Jacques Loeb showed that scientists could achieve artificial parthenogenesis with some types of annelid worm eggs through a series of experiments in 1900. Loeb published the results of his experiments in 1901 as "Experiments on Artificial Parthenogenesis in Annelids (Chaetopterus) and the Nature of the Process of Fertilization," in The American Journal of Physiology. Loeb 's results broadened the range of animals to which artificial parthenogenesis applied beyond sea urchins.

Format: Articles

Subject: Experiments

"Maternal Thyroid Deficiency During Pregnancy and Subsequent Neuropsychological Development of the Child" (1999), by James E. Haddow et al.

From 1987 to the late 1990s, James Haddow and his team of researchers at the Foundation for Blood Research in Scarborough, Maine, studied children born to women who had thyroid deficiencies while pregnant with those children. Haddow's team focused the study on newborns who had normal thyroid function at the time of neonatal screening. They tested the intelligence quotient, or IQ, of the children, ages eight to eleven years, and found that all of the children born to thyroid-hormone deficient mothers performed less well than the control group.

Format: Articles

Subject: Experiments

"The Adaptive Significance of Temperature-Dependent Sex Determination in a Reptile" (2008), by Daniel Warner and Richard Shine

In 2008 researchers Daniel Warner and Richard Shine tested the Charnov-Bull model by conducting experiments on the Jacky dragon (Amphibolurus muricatus), in Australia. Their results showed that temperature-dependent sex determination(TSD) evolved in this species as an adaptation to fluctuating environmental temperatures. The Charnov-Bull model, proposed by Eric Charnov and James Bull in 1977, described the evolution of TSD, although the model was, for many years, untested.

Format: Articles

Subject: Experiments

York v. Jones (1989)

In the case York v. Jones (1989), the United States District Court for the Eastern District of Virginia was one of the first US courts to address a dispute over a cryopreserved preembryo. Steven York and Risa Adler-York (the Yorks), a married couple, provided their gametes to doctors who created the preembryo, which the court referred to as a pre-zygote, as part of an in vitro fertilization (IVF) program at the Howard and Georgeanna Jones Institute for Reproductive Medicine (Jones Institute) in Norfolk, Virginia.

Format: Articles

Subject: Legal

John Spangler Nicholas (1895-1963)

John Spangler Nicholas, an American biologist, was born on 10 March 1895 in Allegheny, Pennsylvania. He was the only child of Elizabeth Ellen Spangler, a teacher, and Samuel Trauger Nicholas, a Lutheran minister. Nicholas held myriad administrative positions throughout his life and his contributions to biology spanned several sub-disciplines, but his most notable accomplishments were in the field of embryology.

Format: Articles

Subject: People

Ernst Heinrich Philipp August Haeckel (1834-1919)

Ernst Heinrich Philipp August Haeckel was a prominent comparative anatomist and active lecturer in the late nineteenth and early twentieth centuries. He is most well known for his descriptions of phylogenetic trees, studies of radiolarians, and illustrations of vertebrate embryos to support his biogenetic law and Darwin's work with evolution. Haeckel aggressively argued that the development of an embryo repeats or recapitulates the progressive stages of lower life forms and that by studying embryonic development one could thus study the evolutionary history of life on earth.

Format: Articles

Subject: People