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Conjoined Twins

Conjoined twins are twins whose bodies are anatomically joined in utero. The degree to which the twins are attached can range from simple, involving skin and cartilage, to complex, including fusion of the skull(s), brain(s), or other vital organs. There are more than a dozen classifications of conjoined twins but what they all tend to have in common is the sharing of the chorion, placenta, and amniotic sac.

Format: Articles

Subject: Disorders, Reproduction

Effects of Prenatal Alcohol Exposure on Cardiac Development

A variety of developmental defects occur as a result of prenatal exposure to alcohol (ethanol) in utero. In humans, those defects are collectively classified as Fetal Alcohol Spectrum Disorders, with Fetal Alcohol Syndrome (FAS) representing the more severe defects. FAS is defined by pre- and post-natal growth retardation, minor facial abnormalities, and deficiencies in the central nervous system (CNS). In addition to those defects, prenatal exposure to alcohol impacts cardiogenesis, the developmental stage of heart formation.

Format: Articles

Subject: Disorders, Reproduction

Father Frank Pavone (1959- )

Father Frank Pavone, a key proponent of the Roman Catholic Church's pro-life movement, has devoted his life's work to ending abortion, euthanasia, embryonic stem cell research, and other techniques and procedures that he believes threaten human life from conception to death. His contributions to the pro-life movement include founding a new religious order called the Missionaries of the Gospel of Life and participating in high-profile protests and television interviews for the pro-life cause.

Format: Articles

Subject: People, Religion, Reproduction

Barbara McClintock's Transposon Experiments in Maize (1931–1951)

Barbara McClintock conducted experiments on corn (Zea mays) in the United States in the mid-twentieth century to study the structure and function of the chromosomes in the cells. McClintock researched how genes combined in corn and proposed mechanisms for how those interactions are regulated. McClintock received the Nobel Prize in Physiology or Medicine in 1983, the first woman to win the prize without sharing it. McClintock won the award for her introduction of the concept of transposons, also called jumping genes.

Format: Articles

Subject: Experiments

"Control of Corneal Differentiation by Extracellular Materials" (1974), by Stephen Meier and Elizabeth D. Hay

In 1974, Elizabeth Dexter Hay and Stephen Meier in the US conducted an experiment that demonstrated that the extracellular matrix, the mesh-like network of proteins and carbohydrates found outside of cells in the body, interacted with cells and affected their behaviors. In the experiment, Hay and Meier removed the outermost layer of cells that line the front of the eye, called corneal epithelium, from developing chick embryos.

Format: Articles

Subject: Experiments

The inductive capacity of oral mesenchyme and its role in tooth development (1969-1970), by Edward J. Kollar and Grace R. Baird

Between February 1969 and August 1970 Edward Kollar and Grace Baird, from the University of Chicago in Chicago, Illinois, published three papers that established the role of the mesenchyme in tooth induction. Drawing upon a history of using tissue interactions to understand differentiation, Kollar and Baird designed their experiments to understand how differentiated structures become specified. Their work overturned a widely accepted model that epithelium controls the identity of the structure, a phenomenon called structural specificity.

Format: Articles

Subject: Experiments

Kurt Benirschke (1924-)

Kurt Benirschke studied cells, placentas, and endangered species in Germany and the US during the twentieth century. Benirschke was professor at the University of California in San Diego, California, and a director of the research department at the San Diego Zoo in San Diego, California. He also helped form the research department of the San Diego Zoo and its sister organization, the Center for Reproduction of Endangered Species.

Format: Articles

Subject: People

William Smellie (1697–1763)

William Smellie helped to incorporate scientific medicine into the process of childbirth in eighteenth century Britain. As a male physician practicing in childbirth and female reproductive health (man-midwife), Smellie developed and taught procedures to treat breech fetuses, which occur when a fetus fails to rotate its head towards the birth canal during delivery. Throughout his career, Smellie compiled a wealth of information about female anatomy in his writings. He modified medical technology such as the obstetrical forceps, an instrument used to maneuver the fetus during childbirth.

Format: Articles

Subject: People, Reproduction

Trial of Madame Restell (Ann Lohman) for Abortion (1841)

In the spring of 1841, abortionist Ann Lohman, called Madame Restell, was convicted for crimes against one of her abortion clients, Maria Purdy. In a deathbed confession, Purdy admitted that she had received an abortion provided by Madame Restell, and she further claimed that the tuberculosis that she was dying from was a result of her abortion. Restell was charged with administering an illegal abortion in New York and her legal battles were heavily documented in the news.

Format: Articles

Subject: Theories

Griswold v. Connecticut (1965)

The landmark Supreme Court case, Griswold v. Connecticut (1965), gave women more control over their reproductive rights while also bringing reproductive and birth control issues into the public realm and more importantly, into the courts. Bringing these issues into the public eye allowed additional questions about the reproductive rights of women, such as access to abortion, to be asked. This court case laid the groundwork for later cases such as Eisenstadt v. Baird (1972) and Roe v. Wade (1973).

Format: Articles

Subject: Legal, Reproduction

The Apgar Score (1953-1958)

In 1952 Virginia Apgar, a physician at the Sloane Women’s Hospital in New York City, New York, created the Apgar score as a method of evaluating newborn infants’ health to determine if they required medical intervention. The score included five separate categories, including heart rate, breathing rate, reaction to stimuli, muscle activity, and color. An infant received a score from zero to two in each category, and those scores added up to the infant’s total score out of ten. An infant with a score of ten was healthy, and those with low scores required medical attention at birth.

Format: Articles

Subject: Technologies, Processes

"RNA-Guided Human Genome Engineering via Cas 9" (2013), by Prashant Mali, Luhan Yang, Kevin M. Esvelt, John Aach, Marc Guell, James E. DiCarlo, Julie E. Norville, and George M. Church

In 2013, George Church and his colleagues at Harvard University in Cambridge, Massachusetts published RNA-Guided Human Genome Engineering via Cas 9, in which they detailed their use of RNA-guided Cas 9 to genetically modify genes in human cells. Researchers use RNA-guided Cas 9 technology to modify the genetic information of organisms, DNA, by targeting specific sequences of DNA and subsequently replacing those targeted sequences with different DNA sequences. Church and his team used RNA-guided Cas 9 technology to edit the genetic information in human cells.

Format: Articles

Subject: Publications

“Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types: Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III” (1944) by Oswald Avery, Colin MacLeod and Maclyn McCarty

In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty published an article in which they concluded that genes, or molecules that dictate how organisms develop, are made of deoxyribonucleic acid, or DNA. The article is titled “Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types: Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III,” hereafter “Transformation.” The authors isolated, purified, and characterized genes within bacteria and found evidence that those genes were made of DNA and not protein.

Format: Articles

Subject: Publications

“Revival of Spermatozoa after Dehydration and Vitrification at Low Temperatures” (1949), by Christopher Polge, Audrey Ursula Smith, and Alan Sterling Parkes

In the 1949 article “Revival of Spermatozoa after Dehydration and Vitrification at Low Temperatures,” researchers Christopher Polge, Audrey Ursula Smith, and Alan Sterling Parkes demonstrated that glycerol prevents cells from dying while being frozen. Polge and his colleagues discussed several procedures in which they had treated sperm cells from various species with glycerol, froze those cells, and then observed the physiological effects that freezing had on the treated sperm. The researchers concluded that glycerol safely preserves sperm samples from a variety of species.

Format: Articles

Subject: Publications

"Male Development of Chromosomally Female Mice Transgenic for Sry gene" (1991), by Peter Koopman, et al.

Early 1990s research conducted by Peter Koopman, John Gubbay, Nigel Vivian, Peter Goodfellow, and Robin Lovell-Badge, showed that chromosomally female (XX) mice embryos can develop as male with the addition of a genetic fragment from the Y chromosome of male mice. The genetic fragment contained a segment of the mouse Sry gene, which is analogous to the human SRY gene. The researchers sought to identify Sry gene as the gene that produced the testis determining factor protein (Tdf protein in mice or TDF protein in humans), which initiates the formation of testis.

Format: Articles

Subject: Experiments

Gonzales v. Planned Parenthood Federation of America, Inc. (2007)

Gonzales v. Planned Parenthood Federation of America, Inc. (Gonzales v. Planned Parenthood) was the 2007 US Supreme Court case in which the Court declared the Partial Birth Abortion Ban Act of 2003 constitutional, making partial birth abortions illegal. In 2003, the US Congress passed the Partial-Birth Abortion Ban Act, which prohibited an abortion technique called partial birth abortion. A partial birth abortion is similar to, but not the same as, a Dilation and Extraction or D&X abortion, which is what the Ban was intended to prohibit. Gonzales v.

Format: Articles

Subject: Legal

Carol Downer (1933– )

Carol Downer was a reproductive health and abortion rights activist in the twentieth and twenty-first centuries in the US and other countries. During the late 1960s, many women reported knowing little about female anatomy and receiving little information from their physicians. Downer advocated for women’s reproductive anatomy education and encouraged women to not rely on the intervention of a medical doctor for all reproductive issues.

Format: Articles

Nelson v. Planned Parenthood Center of Tucson (1973)

The 1973 case Nelson v. Planned Parenthood Center of Tucson established the legality of abortion in Arizona. The Arizona Court of Appeals ruled that the Arizona Revised Statutes 13-211, 13-212, and 13-213, collectively called the Arizona abortion statutes, were unconstitutional. The statutes had made illegal receiving, providing, or advertising abortions. After the Arizona Appeals Court heard the case, it decided that the Arizona abortion statutes were constitutional. However, two weeks later the US Supreme Court decided in Roe v.

Format: Articles

Subject: Legal

"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

City of Akron v. Akron Center for Reproductive Health (1983)

In the 1983 case City of Akron v. Akron Center for Reproductive Health the US Supreme Court ruled that certain requirements of the city of Akron’s “Regulation on Abortion” ordinance violated women’s rights to abortions. Despite the legalization of abortion in the 1973, with the US Supreme Court case Roe v. Wade, individual states passed legislation regulating certain aspects of abortion.

Format: Articles

Subject: Legal

Tomorrow's Children (1934)

Tomorrow's Children is a film that tells the story of Alice Mason, a young woman whom the US government forcibly sterilizes because she comes from a family with a history of alcoholism, mental illnesses, and physical disabilities, traits that they considered biologically determined and inferior. The film, released in 1934, was directed by Crane Wilbur, produced by Bryan Foy, written by Wilbur and Wallace Thurman, and released by Foy Productions Ltd.

Format: Articles

Subject: Publications

"CRISPR /Cas9-mediated Gene Editing in Human Tripronuclear Zygotes" (2015), by Junjiu Huang et al.

In 2015, Junjiu Huang and his colleagues reported their attempt to enable CRISPR/cas 9-mediated gene editing in nonviable human zygotes for the first time at Sun Yat-Sen University in Guangzhou, China. Their article, CRISPR /Cas9-mediated Gene Editing in Human Tripronuclear Zygotes, was published in Protein and Cell. Nonviable zygotes are sperm-fertilized eggs that cannot develop into a fetus. Researchers previously developed the CRISPR/cas 9 gene editing tool, which is a system that originated from bacteria as a defense mechanism against viruses.

Format: Articles

Subject: Publications, Experiments

The Debate over DNA Replication Before the Meselson-Stahl Experiment (1953–1957)

Between 1953 and 1957, before the Meselson-Stahl experiment verified semi-conservative replication of DNA, scientists debated how DNA replicated. In 1953, James Watson and Francis Crick proposed that DNA was composed of two helical strands that wound together in a coil. Their model suggested a replication mechanism, later termed semi-conservative replication, in which parental DNA strands separated and served as templates for the replication of new daughter strands.

Format: Articles

Subject: Theories

Johannes Holtfreter (1901-1992)

Johannes Holtfreter made important discoveries about the properties of the organizer discovered by Hans Spemann. Although he spent much time away from the lab over many years, he was a productive researcher. His colleagues noted that the time he spent away helped revitalize his ideas. He is credited with the development of a balanced salt medium to allow embryos to develop; the discovery that dead organizer tissue retains inductive abilities; and the development of specification, competence, and distribution of fate maps in the developing frog embryo.

Format: Articles

Subject: People

Patrick Christopher Steptoe (1913-1988)

Patrick Christopher Steptoe was a British gynecologist responsible for major advances in gynecology and reproductive technology. Throughout his career Steptoe promoted laparoscopy, a minimally invasive surgical technique that allows a view inside the abdominal cavity, successfully advancing its usefulness in gynecology. After partnering with embryologist Robert Edwards in 1966, the pair performed the first in vitro fertilization in humans.

Format: Articles

Subject: People, Reproduction