Other stem cells are less committed and retain the potential to differentiate into many types of cells.It is believed that stem cells also form reservoirs of repair cells to replace cells and tissues that degenerate over the life span of the organism.Tags: Essay For Educational GoalsPersuasive No Smoking EssaysCompare And Contrast Essay On Gender DifferencesSpeech And EssayEssay On Goals Of My LifeTransition Words For Persuasive EssaysFsu Essay TopicPersuasive Articles On AbortionGood Introductions College Application EssaysEssays About Sister Carrie
In both examples, the tissue involved naturally renews itself from its pool of stem cells—a property that can be exploited for medical use.
It is possible that similar approaches can be developed for other tissues (such as muscle).
One obvious benefit is that this would avoid the problem of rejection if cells generated from the h ES cells were transplanted into the donor.
Whether this approach will be technically or economically feasible is unclear.
Adult stem cells can be obtained from various tissues of adults or in some cases from neonatal tissues.
A well-known example of the use of adult stem cells is bone marrow transplantation.The report was not published in a scientific journal and therefore did not meet the higher standard of peer review, but the company claimed that its scientists had caused human somatic cells to revert to the primordial state by fusing them with cow eggs.From this fusion product, a small clump of cells resembling ES cells appears to have been isolated (Wade, 1998).Hematopoietic (blood-forming) adult stem cells from bone marrow or from umbilical cord blood give rise to all the cells of the blood.Skin cell transplants similarly rely on the transfer of skin stem cells.A more likely benefit of the technology is that it would further facilitate a wide range of experiments to explore the underpinnings of genetic disease and possible forms of amelioration and cure, many of which would not be possible using h ES cells derived from blastocysts generated by fertilization (IVF), whose nuclear genomes are not defined.Although the promise of such research is as yet unrealized, most researchers believe that it will be a critical source of both important knowledge and clinical resources.In addition to those research accomplishments, the cloning of Dolly the sheep in 1997 using a technique called somatic cell nuclear transfer or, more simply, nuclear transfer (NT), illustrated another means by which to generate and isolate h ES cells.h ES cell preparations could potentially be produced by using NT to replace the nucleus of a human oocyte, triggering development, and then isolating h ES cells at the blastocyst stage.However, in many other tissues, natural self-renewal appears to be a slow process, and stem cells for such tissues are correspondingly harder to characterize and isolate.There is also the possibility that some tissues may not contain a distinct subpopulation of undifferentiated stem cells at all.