Fischbach, G.D. (2003). The dangers of delay. Newsweek Atala, A. (2002). Tissue engineering, stem cells, and Elfstrom, G. (2001). What can genetic engineering accomplish? There is limited evidence associating ESC with any particularly impressive scientific breakthrough (Korobkin & Munzer, 2007). Nevertheless, many scientists across the globe believe firmly that these particular cells have long-term potential to be of enormous benefit to scientists as they learn to work with the material more effectively. At the present time, the majority of positive research findings are being generated by research focused on ASCs. Whether this is due to the fact that such research is less rigorously controlled - and cells more readily obtained, often from the very individual who will benefit from the treatment - is an important issue. The National Institutes of Health (NIH) (2008), the American body responsible under presidential orders for overseeing and regulating such research, takes the position that both ESCs and ASCs are viable for important research directed at developing medical treatments and interventions. While ESCs may be more flexible and able to differentiate indefinitely from a single cell, ASCs are readily obtained from a variety of sources. ASCs are said to be more immunogenic than ESCs (Atala, 2002; Korobkin & Munzer, 2007). ESCs are said to be more difficult to differentiate uniformly and homogeneously into a target tissue than ASCs and more likely to be rejected after transplantation; they are also known as tumorigenic or capable of forming tumors or promoting tumor formation. ASCs, in contrast, are difficult to obtain in large numbers needed for extensive research and likely to live shorter "lives' in cultures than ESCs (Korobkin & Munzer, 2007). National Institutes of Health. (2008). Stem cell information: Fede |