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As with many discoveries, a long history of research and contributions from many scientists are pivotal. Stem cell history is no different.
With the advent of the microscope followed by the discovery of cells, scientists probed deeper to understand the biochemistry of cell biology – how cells propagate and give rise to another cell and then tissues.
Late 1800s: The history of stem cell research started in the late 1800s when scientists tried to fertilize mammalian eggs in vitro but only met with slight success which could've been improved with more advanced research tools.
1960s: Another success was made when researchers in the early to mid 1960s revealed that sexual organs of mice possess some unique cells that could give rise to various other kinds of cells. With this finding, researchers first began to think about stem cells.
1978: The discovery of stem cells in human cord blood.
1988: Embryonic stem cell lines from a hamster.
1998: James Thomson at the University of Wisconsin isolated human embryo cells from a human blastocyst -- a hollow structure, which is made up of an outer layer of cells, a fluid cavity and the inner mass. Stem cells are found in the inner mass of blastocysts, which are removed and cultured in a culture dish where the stems cells grow over time.
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What Are Stem Cells?
Stem cells are cells that have the potential to develop into different kinds of cells including muscle and brain cells. In addition, they are capable of dividing and renewing themselves over a long period of time. At present, scientists are working with two types of stems cells that have been taken from animals and humans. Scientists under certain experimental conditions are able to grow stem cells in labs and induce them to become cells with special functions. Not only embryonic stem cells, but also adult stem cells found in bone marrow, muscle and brain can generate new cells that have been lost through wear and tear, injury or disease.
Adult stem cells generate similar cell types of the tissue they reside in. For example, bone marrow adult stem cells will generally produce cells such as red blood cells and white blood cells and platelets. However, embryonic stem cells can be extracted from a three to five day old embryo and they have the potential to grow into many different kinds of specialized cells.
Adult stem cells are considered as multi-potent and human embryonic cells are pluri-potent in nature. Scientists are now trying to find out more about the nature of stem cells - for example 1) how such cells remain unspecialized for many years and 2) identify the signals that cause stem cells to become specialized cells. They believe that stem cell research could help in the treatment of severe diseases including Parkinson’s disease, traumatic spinal cord injury, and heart diseases among others. In addition, it can also help in screening drugs, toxins and birth defects.
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