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Displaying 76 - 100 of 126 items.

Paul Kammerer's Experiments on Salamanders (1903-1912)

In the early twentieth century, Paul Kammerer conducted a series of experiments to demonstrate that organisms could transmit characteristics acquired in their lifetimes to their offspring. In his 1809 publication, zoologist Jean-Baptiste Lamarck had hypothesized that living beings can inherit features their parents or ancestors acquired throughout life. By breeding salamanders, as well as frogs and other organisms, Kammerer tested Lamarck's hypothesis in an attempt to provide evidence for Lamarck's theory of the inheritance of acquired characteristics.

Format: Articles

Subject: Experiments

"The Development of the Pronephros during the Embryonic and Early Larval Life of the Catfish (Ictalurus punctatus)" (1932), by Rachel L. Carson

Rachel L. Carson studied biology at Johns Hopkins University in Maryland and graduated in 1933 with an MA upon the completion of her thesis, The Development of the Pronephros during the Embryonic and Early Larval Life of the Catfish (Ictalurus punctatus). The research that Carson conducted for this thesis project grounded many of the claims and observations she presented in her 1962 book, Silent Spring.

Format: Articles

Subject: People, Experiments, Publications

"On the Induction of Embryonic Primordia by Implantation of Organizers from Different Species" (1924), Hilde Mangold's Dissertation

Hilde Proscholdt Mangold was a doctoral student at the Zoological Institute at the University of Freiburg in Freiburg, Germany, from 1920-1923. Mangold conducted research for her dissertation 'On the Induction of Embryonic Primordia by Implantation of Organizers from Different Species' ('Ueber Induktion von Embryonanlagen durch Implantation artfremder Organisatoren'), under the guidance of Hans Spemann, a professor of zoology at the University of Freiburg.

Format: Articles

Subject: Experiments, Publications

Paul Kammerer's Experiments on Sea-squirts in the Early Twentieth Century

In the early twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, experimented on sea-squirts (Ciona intestinalis). Kammerer claimed that results from his experiments demonstrated that organisms could transmit characteristics that they had acquired in their lifetimes to their offspring. Kammerer conducted breeding experiments on sea-squirts and other organisms at a time when Charles Darwin's 1859 theory of evolution lacked evidence to explain how offspring inherited traits from their parents.

Format: Articles

Subject: Experiments, Organisms

"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

Robert Geoffrey Edwards's Study of in vitro Mammalian Oocyte Maturation, 1960 to 1965

In a series of experiments between 1960 and 1965, Robert Geoffrey Edwards discovered how to make mammalian egg cells, or oocytes, mature outside of a female's body. Edwards, working at several research institutions in the UK during this period, studied in vitro fertilization (IVF) methods. He measured the conditions and timings for in vitro (out of the body) maturation of oocytes from diverse mammals including mice, rats, hamsters, pigs, cows, sheep, and rhesus monkeys, as well as humans.

Format: Articles

Subject: Experiments, Reproduction

"Formation of Genetically Mosaic Mouse Embryos and Early Development of Lethal (t12/t12)-Normal Mosaics" (1964), by Beatrice Mintz

The paper "Formation of Genetically Mosaic Mouse Embryos and Early Development of Lethal (t12/t12)-Normal Mosaics," by Beatrice Mintz, describes a technique to fuse two mouse embryos into a single embryo. This work was published in the Journal of Experimental Zoology in 1964. When two embryos are correctly joined before the 32-cell stage, the embryo will develop normally and exhibit a mosaic pattern of cells as an adult.

Format: Articles

Subject: Experiments

"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

"Experiments on the Development of Chick and Duck Embryos, Cultivated in vitro" (1932), by Conrad Hal Waddington

Conrad Hal Waddington's "Experiments on the Development of Chick and Duck Embryos, Cultivated in vitro," published in 1932 in Philosophical Transactions of the Royal Society of London, Series B, compares the differences in the development of birds and amphibians. Previous experiments focused on the self differentiation of individual tissues in birds, but Waddington wanted to study induction in greater detail. The limit to these studies had been the amount of time an embryo could be successfully cultivated ex vivo.

Format: Articles

Subject: Experiments

"Experiments in Transplanting Limbs and Their Bearing Upon the Problems of the Development of Nerves" (1907), by Ross Granville Harrison

In his 1907 paper, "Experiments in Transplanting Limbs and Their Bearing Upon the Problems of the Development of Nerves," in the Journal of Experimental Zoology that he edited, Ross Granville Harrison tested the development of nerves in transplanted tissue. He studied neural development by examining two competing theories. Victor Hensen proposed a syncytial theory as a way to explain neural development, suggesting that all the nerves of an embryo were connected directly by cytoplasm laid down early in development, and leaving no room for later modification.

Format: Articles

Subject: Experiments

Nicole Le Douarin and Charles Ordahl's Experiments on the Developmental Lineages of Somites

Through various studies developmental biologists have been able to determine that the muscles of the back, ribs, and limbs derive from somites. Somites are blocks of cells that contain distinct sections that diverge into specific types (axial or limb) of musculature and are an essential part of early vertebrate development. For many years the musculature of vertebrates was known to derive from the somites, but the exact developmental lineage of axial and limb muscle progenitor cells remained a mystery until Nicole Le Douarin and Charles P.

Format: Articles

Subject: Experiments

"On the Nature of the Process of Fertilization and the Artificial Production of Normal Larvae (Plutei) From the Unfertilized Eggs of the Sea Urchin" (1899), by Jacques Loeb

Jacques Loeb developed procedures to make embryos from unfertilized sea urchin eggs in 1899. Loeb called the procedures "artificial parthenogenesis," and he introduced them and his results in "On the Nature of the Process of Fertilization and the Artificial Production of Norma Larvae (Plutei) from the Unfertilized Eggs of the Sea Urchin" in an 1899 issue of The American Journal of Physiology. In 1900 Loeb elaborated on his experiments.

Format: Articles

Subject: Experiments

"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

"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

"Presence of Fetal DNA in Maternal Plasma and Serum" (1997), by Dennis Lo, et al.

In the late 1990s researchers Yuk Ming Dennis Lo and his colleagues isolated fetal DNA extracted from pregnant woman’s blood. The technique enabled for more efficient and less invasive diagnoses of genetic abnormalities in fetuses, such as having too many copies of chromosomes.

Format: Articles

Subject: Experiments

Hox Genes and the Evolution of Vertebrate Axial Morphology Experiment (1995)

In 1995, researchers Ann Burke, Craig Nelson, Bruce Morgan, and Cliff Tabin in the US studied the genes that regulate the construction of vertebra in developing chick and mouse embryos, they showed similar patterns of gene regulation across both species, and they concluded that those patterns were inherited from an ancestor common to all vertebrate animals. The group analyzed the head-to-tail (anterior-posterior) axial development of vertebrates, as the anterior-posterior axis showed variation between species over the course of evolutionary time.

Format: Articles

Subject: Experiments

"Congenital Club Foot in the Human Fetus" (1980), by Ernesto Ippolito and Ignacio Ponseti

In 1980, Ernesto Ippolito and Ignacio Ponseti published their results on a histological study they performed on congenital club foot in human fetuses. The researchers examined the feet of four aborted fetuses and compared the skeletal tissues from healthy feet to those affected by congenital club foot. Infants born with club foot are born with one or both feet rigidly twisted inwards and upwards, making typical movement painful and challenging.

Format: Articles

Subject: Experiments

Stanley Alan Plotkin's Development of a Rubella Vaccine (1969)

In the US during the late 1960s, Stanley Alan Plotkin, John D. Farquhar, Michael Katz, and Fritz Buser isolated a strain of the infectious disease rubella and developed a rubella vaccine with a weakened, or attenuated, version of the virus strain. Rubella, also called German measles, is a highly contagious disease caused by the rubella virus that generally causes mild rashes and fever. However, in pregnant women, rubella infections can lead to developmental defects in their fetuses.

Format: Articles

Subject: Experiments

Ginger as a Treatment for Nausea and Vomiting in Pregnancy by Teraporn Vutyavanich, Theerajana Kraisarin, and Rung-Aroon Ruangsri (1998–2001)

In 1998 and 1999, Teraporn Vutyavanich, Theerajana Kraisarin, and Rung-Aroon Ruangsri in Thailand showed that ginger alleviated nausea in pregnant women. Vutyavanich and his colleagues found that the group of pregnant women who took ginger capsules reported significantly fewer nausea symptoms and vomiting episodes than the group who only received the placebo. Vutyavanich and his team’s study at Chiang Mai University in Chiang Mai, Thailand, was one of the earliest to investigate and support the use of ginger as an effective treatment for relieving pregnancy-related nausea and vomiting.

Format: Articles

Subject: Experiments

"Interspecific Chimeras in Mammals: Successful Production of Live Chimeras Between Mus musculus and Mus caroli" (1980), by Janet Rossant and William I. Frels

In 1980 Janet Rossant and William I. Frels published their paper, "Interspecific Chimeras in Mammals: Successful Production of Live Chimeras Between Mus musculus and Mus caroli," in Science. Their experiment involved the first successful creation of interspecific mammalian chimeras. Mammalian chimeras are valuable for studying early embryonic development. However, in earlier studies, clonal analysis was restricted by the lack of a cell marker, present at all times, that makes a distinction between the two parental cell types in situ.

Format: Articles

Subject: Experiments

The First Successful Cloning of a Gaur (2000), by Advanced Cell Technology

Advanced Cell Technology (ACT), a stem cell biotechnology company in Worcester, Massachusetts, showed the potential for cloning to contribute to conservation efforts. In 2000 ACT researchers in the United States cloned a gaur (Bos gaurus), an Asian ox with a then declining wild population. The researchers used cryopreserved gaur skin cells combined with an embryo of a domestic cow (Bos taurus). A domestic cow also served as the surrogate for the developing gaur clone.

Format: Articles

Subject: Experiments

"The Association between Depressive Symptoms and Social Support in Taiwanese Women During the Month" (2004), by Shu-Shya Heh et al.

In 2004, Shu-Shya Heh, Lindsey Coombes, and Helen Bartlett studied the association between Chinese postpartum (post-childbirth) practices and postpartum depression in Taiwanese women. The researchers surveyed Taiwanese women about the social support they received after giving birth and then evaluated the depression rates in the same women. Heh and her colleagues focused on the month following childbirth, which according to traditional Chinese medicine, is an important period that warrants a set of specialized practices to aid the woman's recovery.

Format: Articles

Subject: Experiments

"Contributions to the Development of the Embryo. On the Artificial Production of One of the First Two Blastomeres, and the Later Development (Postgeneration) of the Missing Half of the Body" (1888), by Wilhelm Roux

Wilhelm Roux was an influential figure in the early history of experimental embryology. Although he originally studied medicine, he was invited to be a Privatdozentur, or unsalaried lecturer, at the Anatomical Institute in Breslau (Wroclaw), Poland, in 1879. He spent the next ten years at this institute, working his way from Dozent to associate professor and finally, in 1889, to director for his own institute, Institut für Entwicklungsgeschichte, or Institute for Developmental History and Mechanics.

Format: Articles

Subject: Experiments

Treatment of Anemia during Pregnancy (1931), by Lucy Wills

In 1931, physician Lucy Wills conducted a study of nutritional deficiencies that caused anemia in pregnant women in Bombay, India, later renamed Mumbai. Anemia is a lack of healthy red blood cells in the blood. Wills published the results of her study in the medical article 'Treatment of ‘Pernicious Anaemia of Pregnancy' and 'Tropical Anaemia'' in the British Medical Journal in 1931. Wills's research contributed to knowledge of anemia and the possible causes associated with the disease, such as the symptoms of fatigue and irritability.

Format: Articles

Subject: Experiments

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.

Format: Articles

Subject: Experiments