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Microscopic 20x view of a colony of undifferentiated human embryonic stems cells (Source University of Wisconsin-Madison.)Stem cells are primal, undifferentiated cells which have the potential to produce any kind of cell in the body. Medical researchers believe stem cells have the potential to change the face of human disease by being used to repair specific tissues or to grow organs.
1 Types
There are three types of stem cells: totipotent, pluripotent, and multipotent. A single totipotent stem cell can grow into an entire organism and even produce extra-embryonic tissues. Blastomeres have this property. Pluripotent stem cells cannot grow into a whole organism, but they are able to differentiate into cells derived from any of the three germ layers. Multipotent (also called unipotent) stem cells can only become one particular type of cells: e.g. blood cells, or bone cells.
Stem cells are also categorized according to their source, as either adult or embryonic. Adult stem cells are indifferentiated cells found among differentiated cells of a specific tissue and are mostly multipotent cells. They are already being used in treatments for over one hundred diseases and conditions, while embryonic stem cell research is a less-developed field and is considered by many researchers to have greater potential as the basis of treatments. Embryonic stem cells are cultured cells obtained from the inner mass cells of a blastocyst. Research with embryonic stem cells is controversial because it requires destruction of embryos, which to many people are human beings, meaning that destroying an embryo for any reason is morally unacceptable. On the other side of the issue, people point out that embryonic stem cells have the potential to cure most diseases (since they are pluripotent), and the embryos used would have been discarded by fertility clinics anyway.
2 Sources of stem cells
2.1 Cord blood stem cells
Blood from the placentaThe placenta is an ephemeral (temporary) organ present only in female placental mammals during gestation ( pregnancy). The placenta is composed of two parts, one of which, the chorion, is genetically and biologically part of the fetus, the other part of t and umbilical cordIn placental mammals, the umbilical cord is a tube that connects a developing embryo or fetus to its placenta. It contains major arteries and veins (notably the umbilical arteries and umbilical vein) for the exchange of nutrient- and oxygen-rich blood bet that are left over after birth is a source of adult stem cells. Since 19881988 is a leap year starting on Friday (click on link for calendar). Events January January 2 Georgia celebrates its bicentennial statehood. January 9 Connecticut celebrates its bicentennial statehood. January 26 Australia celebrates its bicentennial day. these cord blood stem cells have been used to treat Gunther's diseaseGunther's disease is a form of rythropoietic porphyria. It is congenitally acquired. It is a rare disease. There is a deficiency of the enzyme uroporphyrinogen cosynthetase., Hunter syndromeHunter's syndrome is caused by the enzymatic deficiency of L-iduronosulfate sulfatase. This is also called as mucopolysaccharoidosis Type II. Alternative names Mucopolysaccharidosis type II, Iduronate sulfatase deficiency Definition Hunter syndrome is a h, Hurler syndromeHurler syndrome is the deficiency of alpha-L iduronidase resulting in deposition of heparan sulfate and dermatan sulfate. This is also called as mucopolysaccharoidosis Type I. Symptoms appear by age 1 and death usually occurs by 10 years due to cardiovasc, Acute lymphocytic leukaemiaAcute lymphocytic leukaemia ALL , also known as acute lymphoblastic leukaemia is a cancer of the white blood cells, characterised by the overproduction and continuous multiplication of malignant and immature white blood cells (referred to as lymphoblasts) and many more problems occurring mostly in children. It is collected by removing the umbilical cord, cleansing it and withdrawing blood from the umbilical vein. This blood is then immediately analyzed for infectious agents and the tissue-type is determined. Cord blood is stored in liquid nitrogen for later use, when it is thawed and injected through a vein of the patient. This kind of treatment, where the stem cells are collected from another donor, is called allogeneic treatment. When the cells are collected from the same patient they will be used on, it is called autologous and when collected from identical individuals, it is referred to as syngeneic. Xenogeneic transfer of cells between different species is very underdeveloped and is said to have little research potential.
