from animal studies that stem cells can be made to differentiate into cells of choice, and that these cells will act properly in their transplanted environment. In human beings, transplants of hematopoietic stem cells (the cells

Stem Cells : What Are They? Many types of stem cells exist in the human body. All have the capacity to replicate, to self-renew; and they have the capacity to differentiate in order to produce specific body parts such as muscle cells,

tissues of the body require stem cells for normal turnover and repair. Stem cells that are found in developed tissue, regardless of the age of the organism at the time, are referred to as adult stem cells. The most well-known example of this are

Surrounding the Sources of Stem Cells At present, there are three possible sources of stem cells: adult stem cells derived from pediatric or adult donors; embryo germ cell stem cells (EG cells ) derived from aborted fetuses; and embryonic

putting this is to say that stem cells are pluripotent rather than totipotent . It is true that advanced technology might be able to render these cells effectively (if not actually) totipotent. Research undertaken in Canada in 1993 involving the

Why is it that pluripotent stem cells are one step down the embryonic staircase? Totipotent stem cells are capable of producing all tissue, including the trophoblast necessary for implantation. Totipotent stem cells have the potential

embryo to participate in stem cell research to the greatest degree possible, stem cells (and stem cell “lines”) should be identified with respect to their provenance. Patients and researchers should be able to avoid participating in

Human Embryonic Stem Cells The study of human stem cells has barely begun and what is known is summarized in this section. The vast majority of experimental data discussed here are the results of experiments in mice. ES cells from

Stem Cells Stem cells are essentially undifferentiated cells. There are many kinds of stem cells, some more differentiated than others. When they divide, their progeny mature and specialize into a specific type of cell (i.e.

of the potential of human stem cells from these various sources. Embryonic stem cells (ES cells ) derived from early embryos and embryonic germ cells (EG cells) have particular promise for a wide range of therapeutic applications because they