Stem cells are a special form of human life:
So humble an entity, so hot a potato: The panel Stem cell debate ethical guidelines for all future federally funded research on human embryos.
These guidelines helped influence President George W. Stem-cell research has enormous potential value in both medical and commercial terms. Stem cells are the progenitors of all specialized cells in the body.
Blood stem cells hematopoietic cells reside in bone marrow and continuously produce a variety of blood and immune system cells. Mesenchymal stem cells are the source of new bone, cartilage, and connective tissue cells.
Neuronal stem cells produce a variety of nervous system tissue, mostly during early embryonic development but, as we are beginning to learn, later in life as well. During early development the precursors to all these more specialized stem cells, sometimes called "pluripotential stem cells" PSCsare found in the inner cell mass of the preimplantation embryo and in certain cell populations of the early fetus.
Stem-cell research took a great leap forward inwhen two independent research groups, led by Dr. John Gearhart of Johns Hopkins University, reported success in growing human stem cells in culture. Thomson and Gearhart, using different approaches, had isolated these very early precursor cells and Stem cell debate them out on a feeder layer of mouse cells to produce an immortalized pluripotent human stem cell culture.
This resetting allows the cells to be cultured indefinitely during repeated cell divisions or passages. One day, doctors treating a cancer patient with chemotherapy may be able to replace his or her damaged blood or marrow cells with new ones grown from ES cells.
In the future, when better understanding has been gained of the growth factors that induce specific forms of cell differentiation, immortalized PSC lines like these may be induced to produce specific tissue types. Also on the distant horizon lies the possibility of new cardiac tissue for heart attack victims, replacement blood and marrow cells for those who have undergone chemotherapy or radiation therapy for cancer, new skin tissue for burn victims, bone for those suffering from severe fractures or osteoporosis, and so on.
Closely studied, stem cell lines might give scientists new clues about the growth factors that drive tissue differentiation from the earliest embryonic stage forward. This would permit new understanding of cellular abnormalities, including cancer, and new ways of steering cell differentiation in desired paths.
At the end ofthe journal Science, in a special cover article and editorial, declared pluripotent stem cell research to be the scientific "breakthrough" of the year. Inthe journal Science declared pluripotent stem cell research the scientific "breakthrough" of the year.
A funding issue Major legal, ethical, and political hurdles stand in the way of these advances. In large part, these obstacles result from the fact that, of the three sources of stem cells, human embryos are the most promising. One source is the "adult," or mature, stem cells that reside in the body from infancy onward.
These cells are "multipotent," meaning they are able to produce a range of related tissues, such as the differing types of blood system cells.
A second source is embryonic germ cells that are derived from the primordial reproductive tissues of aborted early fetuses.
These are the cells that John Gearhart used in his research. They are pluripotent, able to give rise to all tissue types, although recent research suggests that their usefulness in cell-replacement therapies might be limited because they have already begun to take on some specific characteristics of their reproductive function.
Finally, there are ES cells, derived from the inner cell mass of blastocyst-stage embryos. These pluripotent cells are the most ubiquitous of all. Once removed from the blastocyst they lack the outer trophoblast structures for continued embryonic development, but they can theoretically be "nudged" into becoming any cell type found in the human body.
These are the cells that Thomson used in his research.
In a trice, the groundbreaking work of James Thomson left and John Gearhart brought the issue of government funding of stem-cell research to the fore. Three issues spurred the debate over whether or not the government should fund stem-cell research. One concerned the moral status of PSCs themselves.
Are they morally protectable entities, or are they more like other disposable tissues gleaned from the human body? A second issue concerned the derivation of PSCs.
Assuming that at least during the earliest phases of research, human embryos produced via in vitro fertilization IVF would be the best source for producing immortalized stem cell lines, could research go forward that depended on the dissection of living human embryos? Someday researchers may create new ES cells lines using a technique similar to that brought to bear in the birth of Dolly, the famous cloned sheep.
Finally, there was the question, still somewhat remote but now looming: The hope is that we will develop enough knowledge to do this by manipulating the immune system factors of standardized pluripotent stem cell lines. If this is not possible, each therapeutic intervention will require the preparation of tissues that are immunologically suitable histocompatible for the patient.
InWilmut and his team announced the birth of the cloned sheep Dolly, the first mammal cloned from the cell of an adult animal. A somatic cell could be taken from the recipient individual, its nucleus inserted into an enucleated egg cell that is stimulated to begin dividing, and the resulting blastocyst-stage embryo then disaggregated to produce a histocompatible pluripotent stem cell line.There is considerable debate as to whether some proposed adult cell populations are truly stem cells.
 Embryonic. Embryonic stem cells (ESCs) are the Stem cell therapy is the use of stem cells to treat or prevent a disease or condition. One type of stem cell that is generally not recognized in the stem cell debate because it is not harvested as a source of these important cells is the fertilized egg cell, or zygote.
A cell at this developmental stage is said to be totipotent, which means that it has the potential to create any type of cell necessary for embryonic development. The stem cell controversy is the consideration of the ethics of research involving the development, use, and destruction of human embryos.
Most commonly, this controversy focuses on embryonic stem monstermanfilm.com all stem cell research involves the human embryos. For example, adult stem cells, amniotic stem cells, and induced pluripotent stem cells do not involve creating, using, or destroying human.
human stem cell research and experimentation: all sides to the debate. The information used to compile this Stem Cell Research Timeline comes from many different sources, including the National Institutes of Health.A useful list of links to other stem cell research timelines from around the Web can be found at the bottom of this page.
Sep 07, · Stem cell debate in the Muslim world. Islam does not have a centralised authority - like the Vatican in Roman Catholicism - to state its position.