Stem Cells are unspecialized cells that have the ability to replenish rapidly themselves though long periods of cell division and, maybe even more importantly, when given the correct chemical signals they can specialize themselves into nearly any type of cell. To be classified as a stem cell, any cellular candidate must possess the two properties: it must have a potential for rapid and extended periods of cellular division while remaining unchanged, and it must contain the capacity to differentiate into any mature type of cell. Stem cells are generally divided into four categories, although the last two are only sometimes referred to as stem cells:
- Totipotent stem cells: These are stem cells that can differentiate into any specialized cell type, even the placenta. The fertilized egg, and the cells immediately created during the first days of a fetus’ development are totipotent stem cells.
- Pluripotent stem cells: These are stem cells that can differentiate themselves into any specialized cell type except for totipotent stem cells and placenta cells. Pluripotent stem cells begin forming around the fourth day of fetus development.
- Multipotent stem cells: These are stem cells that have the ability to differentiate only into a specialized group of related cells. Hematopoietic stem cells, for example, can differentiate into any of the specialized cells within the blood.
- Progenitor cells: Also known as unipotent stem cells, are limited to differentiating themselves into a single specific cell type. Erythroid progenitor cells can develop into red blood cells, and only red blood cells.
When someone talks about stem cell research, many people immediately think of the ongoing argument around the embryonic stem cell research. Embryonic stem cell research causes controversy because the embryo from which the cells are taken is ultimately destroyed and its opponents usually take moral or ethical objection to this. However, as this discovery shows, there are other forms of stem cell research which are must less morally grey. Using stem cell research to change stem cells in marrow into viable sperm is a procedure which can benefit everyone and harm no one.
James E. Murray - I guess I've written enough articles here that I should finally make my profile. My name is James Murray. I am an ex-special operations ...
