Stem Cells - The New York Times

 

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A free collection of articles about stem cells published in The New York Times. A free collection of articles about stem cells published in The New York Times. Learn about the types of stem cells and stem cell therapies available for uses in cancer treatment, bone marrow transplantation, and spinal cord injury, as well as research. Discover information on stem cell transplants, therapy, and learn the definition of what stem cells are. Medema J.P. | N Engl J Med ; Two recent studies in mice show that, on ablation of colon cancer stem cells, differentiated cancer cells can dedifferentiate to supply a new pool of.


Stem cell - Wikipedia


Stem cellan undifferentiated cell that can divide to produce some offspring cells that continue as stem cells and some cells that are destined to differentiate become specialized. Stem cells are an ongoing source of the differentiated cells that make up the tissues and organs of animals and plants. There is great interest in stem cells because they have potential in the development of therapies for replacing defective or damaged cells resulting from a variety of disorders and injuries, such as Parkinson diseaseheart diseaseand diabetes.

There are two major types of stem cells: embryonic stem cells and adult stem cells, which are also called tissue stem cells, stem cells article. Embryonic stem cells often referred to as ES cells are stem cells that are derived from the inner cell mass of a mammalian embryo at a very early stage of development, when it is composed of a hollow sphere of dividing cells a blastocyst.

Embryonic stem cells from human embryos and from embryos of certain other mammalian species can be grown in tissue culture. The most-studied embryonic stem cells are mouse embryonic stem cells, which were first reported in This type of stem cell can be cultured indefinitely in the presence of leukemia inhibitory factor LIFa glycoprotein cytokine. If cultured mouse embryonic stem cells are injected into an early mouse embryo at the blastocyst stage, they will become integrated into the embryo and produce cells that differentiate into most or all of the tissue stem cells article that subsequently develop.

This ability to repopulate mouse embryos is the key defining feature of embryonic stem cells, and because of it they are considered to be pluripotent —that is, able to give rise to any cell type of the adult organism.

If embryonic stem cells are grafted into an adult mouse, they will develop into a type of tumour called a teratomawhich contains a variety of differentiated tissue types. Mouse embryonic stem cells are widely used to create genetically modified mice.

This is done by introducing new genes into embryonic stem cells in tissue culture, selecting the particular genetic variant that is stem cells article, and then inserting the genetically modified cells into mouse embryos. As long as some of the chimeric mice have germ cells sperm or eggs that have been derived from stem cells article embryonic stem cells, it is possible to breed a line of mice that have the same genetic constitution as the embryonic stem cells and therefore incorporate the genetic modification that was made in vitro.

This method has been used to produce thousands of new genetic lines of mice, stem cells article. In many such genetic lines, individual genes have been ablated in order to study their biological function; in others, genes have been introduced that have the same mutations that are found in various human genetic diseases. Extensive experience with mouse embryonic stem cells made it possible for scientists to grow human embryonic stem cells from early human embryos, and the first human stem cell line was created in Human embryonic stem cells are in many respects similar to mouse embryonic stem cells, but they do not require LIF for their maintenance.

The human embryonic stem cells form a wide variety of differentiated tissues in vitro, stem cells article, and they form teratomas when grafted into immunosuppressed mice, stem cells article. Large quantities of cells, such as dopamine -secreting neurons for the treatment of Parkinson disease and insulin -secreting pancreatic beta cells for the treatment of diabetescould be produced from embryonic stem cells for cell transplantation. Cells for this purpose have previously been obtainable only from sources in very limited supply, such as the pancreatic beta cells obtained from the cadavers of human organ donors.

The stem cells article of human embryonic stem cells evokes ethical concerns, stem cells article, because the blastocyst -stage embryos are destroyed in the process of obtaining the stem cells. The embryos from which stem cells have been obtained are produced through in vitro fertilizationand people who consider preimplantation human embryos to be human beings generally believe that such work is morally wrong. Others accept it because they regard the blastocysts to be simply balls of cells, and human cells used in laboratories have not previously been accorded any special moral stem cells article legal status.

Moreover, it is stem cells article that none of the cells of the inner cell mass are exclusively destined to become part of the embryo itself—all of the cells contribute some or stem cells article of their cell offspring to the placentawhich also has not been accorded any special legal status. The divergence of views on this issue is illustrated by the fact that the use of human embryonic stem cells is allowed in some countries and prohibited in others.

In the U. The therapy to be tested was known as GRNOPC1, which consisted of progenitor cells partially differentiated cells that, once inside the body, matured into neural cells known as oligodendrocytes. The therapy was designed for the restoration of nerve function in persons suffering from acute spinal cord injury.

Embryonic germ EG cells, derived from primordial germ cells found in the gonadal ridge of a late embryo, have many of the properties of embryonic stem cells. The primordial germ cells in an embryo develop into stem cells that in an adult generate the reproductive gametes sperm or eggs. In mice and humans it is possible to grow embryonic germ cells in tissue culture with the appropriate stem cells article factors—namely, LIF and another cytokine called fibroblast growth factor, stem cells article.

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Introduction Embryonic stem cells Mouse embryonic stem cells Stem cells article embryonic stem cells Embryonic germ cells Adult stem cells Epithelial stem cells Bone marrow and hematopoietic stem cells Neural stem cells Somatic cell nuclear transfer Induced pluripotent stem cells.

Written By: Jonathan M. See Article History. Embryonic stem cells Embryonic stem cells often referred to as ES cells are stem cells that are derived from the inner cell mass of a mammalian embryo at a very early stage of development, stem cells article, when it is composed of a hollow sphere of dividing cells a blastocyst.

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stem cells article

 

A free collection of articles about stem cells published in The New York Times. A free collection of articles about stem cells published in The New York Times. Autophagy enhances mesenchymal stem cell-mediated CD4 + T cell migration and differentiation through CXCL8 and TGF-β1. Mesenchymal stem cells (MSCs) have been recognized as a promising tool for the treatment of various inflammatory disorders and autoimmune diseases. Medema J.P. | N Engl J Med ; Two recent studies in mice show that, on ablation of colon cancer stem cells, differentiated cancer cells can dedifferentiate to supply a new pool of.