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Displaying 26 - 50 of 124 items.

Corticosteroids' Effect on Fetal Lung Maturation (1972), by Sir Graham Collingwood Liggins and Ross Howie

In a clinical trial from 1969 to 1972, Sir Graham Collingwood Liggins and Ross Howie showed that if doctors treat pregnant women with corticosteroids before those women deliver prematurely, then those women's infants have fewer cases of respiratory distress syndrome than do similarly premature infants of women not treated with corticosteroids. Prior to the study, premature infants born before 32 weeks of gestation often died of respiratory distress syndrome, or the inability to inflate immature lungs.

Format: Articles

Subject: Experiments

Julia Barlow Platt's Embryological Observations on Salamanders' Cartilage (1893)

In 1893, Julia Barlow Platt published her research on the origins of cartilage in the developing head of the common mudpuppy (Necturus maculosus) embryo. The mudpuppy is an aquatic salamander commonly used by embryologists because its large embryonic cells and nuclei are easy to see. Platt followed the paths of cells in developing mudpuppy embryos to see how embryonic cells migrated during the formation of the head. With her research, Platt challenged then current theories about germ layers, the types of cells in an early embryo that develop into adult cells.

Format: Articles

Subject: Experiments, Theories, Processes

"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

Induced Pluripotent Stem Cell Experiments by Kazutoshi Takahashi and Shinya Yamanaka in 2006 and 2007

In 2006, Kazutoshi Takahashi and Shinya Yamanaka reprogrammed mice fibroblast cells, which can produce only other fibroblast cells, to become pluripotent stem cells, which have the capacity to produce many different types of cells. Takahashi and Yamanaka also experimented with human cell cultures in 2007. Each worked at Kyoto University in Kyoto, Japan. They called the pluripotent stem cells that they produced induced pluripotent stem cells (iPSCs) because they had induced the adult cells, called differentiated cells, to become pluripotent stem cells through genetic manipulation.

Format: Articles

Subject: Experiments

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

"Cellular death in morphogenesis of the avian wing" (1962), by John W. Saunders Jr., et al.

In the early 1960s, John W. Saunders Jr., Mary T. Gasseling, and Lilyan C. Saunders in the US investigated how cells die in the developing limbs of chick embryos. They studied when and where in developing limbs many cells die, and they studied the functions of cell death in wing development. At a time when only a few developmental biologists studied cell death, or apoptosis, Saunders and his colleagues showed that researchers could use embryological experiments to uncover the causal mechanisms of apotosis.

Format: Articles

Subject: Experiments

"Proliferation, Differentiation and Degeneration in the Spinal Ganglia of the Chick Embryo under Normal and Experimental Conditions" (1949), by Viktor Hamburger and Rita Levi-Montalcini

In this paper Viktor Hamburger and Rita Levi-Montalcini collaborated to examine the effects of limb transplantation and explantation on neural development. In 1947 Hamburger invited Levi-Montalcini to his lab at Washington University in St. Louis to examine this question. Independently, each had previously arrived at opposing conclusions based on the same data.

Format: Articles

Subject: Experiments

Jeffrey Weinzweig's Experiments on In Utero Cleft Palate Repair in Goats (1999-2002)

Jeffrey Weinzweig and his team, in the US at the turn of the twenty-first century, performed a series of experiments on fetal goats to study the feasibility of repairing cleft palates on organisms still in the womb. Weinzweig , a plastic surgeon who specialized in cleft palate repair, and his team developed a method to cause cleft palates in fetal goats that are similar to clefts that occur in human fetuses. Using their goat congenital model, the team developed a method to repair a congenital cleft palate in utero, or in the womb.

Format: Articles

Subject: Experiments, Disorders

"Genetic Evidence Equating SRY and the Testis-Determining Factor" (1990), by Phillippe Berta et al.

In the late 1980s, Peter Goodfellow in London, UK led a team of researchers who showed that the SRY gene in humans codes a protein that causes testes to develop in embryos. During this time, scientists in London and Paris, including Peter Koompan and John Gubbay, proposed that SRY was the gene on the Y chromosome responsible for encoding the testis-determining factor (TDF) protein. The TDF is a protein that initiates embryo to develop male characteristics.

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

Experimental Studies on Germinal Localization (1904), by Edmund B. Wilson

At the turn of the twentieth century, Edmund B. Wilson
performed experiments to show where germinal
matter was located in molluscs. At Columbia University in New York City,
New York, Wilson studied what causes cells to differentiate during
development. In 1904 he conducted his experiments on molluscs, and he modified the
theory about the location of germinal matter in the succeeding years. Wilson and others modified the
theory of germinal localization to accommodate results that showed

Format: Articles

Subject: Experiments

Sonja Vernes, et al.'s Experiments On the Gene Networks Affected by the Foxp2 Protein (2011)

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.

Format: Articles

Subject: Experiments

Lysogenic Bacteria as an Experimental Model at the Pasteur Institute (1915-1965)

Lysogenic bacteria, or virus-infected bacteria, were the primary experimental models used by scientists working in the laboratories of the Pasteur Institute in Paris, France, during the 1950s and 1960s. Historians of science have noted that the use of lysogenic bacteria as a model in microbiological research influenced the scientific achievements of the Pasteur Institute's scientists.

Format: Articles

Subject: Organisms, Experiments

Elizabeth Blackburn, Carol Greider and Jack Szostak's Telomere and Telomerase Experiments (1982-1989)

Experiments conducted by Elizabeth Blackburn, Carol Greider, and Jack Szostak from 1982 to 1989 provided theories of how the ends of chromosomes, called telomeres, and the enzyme that repairs telomeres, called telomerase, worked. The experiments took place at the Sidney Farber Cancer Institute and at Harvard Medical School in Boston, Massachusetts, and at the University of California in Berkeley, California. For their research on telomeres and telomerase, Blackburn, Greider, and Szostak received the Nobel Prize in Physiology or Medicine in 2009.

Format: Articles

Subject: Experiments

"Programmed Cell Death-II. Endocrine Potentiation of the Breakdown of the Intersegmental Muscles of Silkmoths" (1964), by Richard A. Lockshin and Carroll M. Williams

Richard A. Lockshin's 1963 PhD dissertation on cell death in insect metamorphosis was conducted under the supervision of Harvard insect physiologist Carroll M. Williams. Lockshin and Williams used this doctoral research as the basis for five articles, with the main title "Programmed Cell Death," that were published between 1964 and 1965 in the Journal of Insect Physiology. These articles examine the cytological processes, neuronal and endocrinal controls, and the influence of drugs on the mechanism of cell death observed in pupal muscle structures of the American silkmoth.

Format: Articles

Subject: Experiments, Publications

"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

"Developmental Capacity of Nuclei Transplanted from Keratinized Skin Cells of Adult Frogs" (1975), by John Gurdon, Ronald Laskey, and O. Raymond Reeves

In 1975 John Gurdon, Ronald Laskey, and O. Raymond Reeves published "Developmental Capacity of Nuclei Transplanted from Keratinized Skin Cells of Adult Frogs," in the Journal of Embryology and Experimental Morphology. Their article was the capstone of a series of experiments performed by Gurdon during his time at Oxford and Cambridge, using the frog species Xenopus laevis. Gurdon's first experiment in 1958 showed that the nuclei of Xenopus cells maintained their ability to direct normal development when transplanted.

Format: Articles

Subject: Experiments, Publications

Paul Kammerer (1880-1926)

Paul Kammerer conducted experiments on amphibians and marine animals at the Vivarium, a research institute in Vienna, Austria, in the early twentieth century. Kammerer bred organisms in captivity, and he induced them to develop particular adaptations, which Kammerer claimed the organismss offspring would inherit. Kammerer argued that his results demonstrated the inheritance of acquired characteristics, or Lamarckian inheritance. The Lamarckian theory of inheritance posits that individuals transmit acquired traits to their offspring.

Format: Articles

Subject: Experiments, People

"Human Toxoplasmosis: Occurrence in Infants as an Encephalomyelitis Verification of Transmission to Animals" (1939), by Abner Wolf et al.

In a series of experiments during mid 1930s, a team of researchers in New York helped establish that bacteria of the species Toxoplasma gondii can infect humans, and in infants can cause toxoplasmosis, a disease that inflames brains, lungs, and hearts, and that can organisms that have it. The team included Abner Wolf, David Cowen, and Beryl Paige. They published the results of their experiment in Human Toxoplasmosis: Occurrence in Infants as an Encephalomyelitis Verification of Transmission to Animals.

Format: Articles

Subject: Experiments, Reproduction, Disorders

Alec Jeffreys’s Experiments to Identify Individuals by Their Beta-globin Genes (1977-1979)

In a series of experiments in the late 1970s, Alec J. Jeffreys in the UK and Richard A. Flavell in the Netherlands developed a technique to detect variations in the DNA of different individuals. They compared fragments of DNA from individuals’ beta-globin genes, which produce a protein in hemoglobin. Previously, to identify biological material, scientists focused on proteins rather than on genes. But evidence about proteins enabled scientists only to exclude, but not to identify, individuals as the sources of the biological samples.

Format: Articles

Subject: Experiments

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

The first successful cloning of a gaur in 2000 by Advanced Cell Technology involved the cells of two animals: an egg cell from a domestic cow and a skin cell from a gaur. The researchers extracted the egg cell from the ovary of the domestic cow and the skin cell from the skin of the gaur. First, the researchers performed nuclear transplantation on the egg cell of the cow, during which they removed the nucleus of the egg cell. The mitochondria of the egg cell remained intact inside the cell.

Format: Graphics

Subject: Experiments, Organisms, Reproduction

"Genetic Control of Biochemical Reactions in Neurospora" (1941), by George W. Beadle and Edward L. Tatum

George Wells Beadle and Edward Lawrie Tatum's 1941 article Genetic Control of Biochemical Reactions in Neurospora detailed their experiments on how genes regulated chemical reactions, and how the chemical reactions in turn affected development in the organism. Beadle and Tatum experimented on Neurospora, a type of bread mold, and they concluded that mutations to genes affected the enzymes of organisms, a result that biologists later generalized to proteins, not just enzymes.

Format: Articles

Subject: Experiments

"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 British Doctors’ Study (1951–2001)

From 1951 to 2001, researchers at the University of Oxford in Oxford, England, conducted the British Doctors’ Study, a study that examined the smoking habits, disease rates, and mortality rates of physicians in Britain. Two epidemiologists, scientists who study occurrence and distribution of disease, Richard Doll and Austin Bradford Hill, initiated the study, and statistician Richard Peto joined the team in 1971. The objective of the study was to assess the risks associated with tobacco use, and its relationship to lung cancer.

Format: Articles

Subject: Experiments