In the name of God

1. In the name of God

2. Stem Cells Questions & Answers • http://www.webmd.com/a-to-z-guides/features/stem-cells-faq-9-questions-answers

3. 1- What are stem cells? • Stem cells are unspecialized cells that can become other types of cells.

4. 2-What's the difference between adult stem cells and stem cells taken from an embryo? • Embryonic stem cells are stem cells in an embryo. They can develop into a wide range of cell types. • Scientists have found that a few stem cells persist even after birth; those are adult stem cells. Most adult stem cells can form a limited number of cell types.

5. Stem Cell Cultivation University of Wisconsin-Madison

7. 3- What's the controversy about? • There's no controversy about adult stem cells. But when it comes to embryonic stem cells, some people argue that an embryo is a living human being and destroying an embryo for any reason is morally unacceptable. Other people say that embryonic stem cells have the potential to cure many diseases, and that the embryos used would have been discarded by fertility clinics anyway.

8. 4- Why not just study adult stem cells? • Adult stem cells have some advantages. When they come from your own body, your immune system will probably not try to reject them. And adult stem cells aren't controversial. But there are three main disadvantages to using adult stem cells: • Adult stem cells aren't able to form all types of cells, so their use may be limited.   • Adult stem cells are rare among the body's billions of cells, so they're hard to find.

9. 5-Where do scientists get the embryos they use? • From in vitro fertilization (IVF) clinics. • Many women who have difficulty having a baby use IVF. Doctors collect eggs from the mother and sperm from the father, and put them together in the laboratory. The doctors implant one or more of the resulting embryos in the mother. Other embryos are frozen and stored, in case the first embryo implanted doesn't take. But all of those frozen embryos may not be used. According to federal policy, embryonic stem cells used for research can only come from embryos created for reproductive purposes that are no longer needed and the donors must consent and not profit financially from the donation.

10. 6- Could there be alternatives to studying embryonic stem cells? • Maybe. In 2007, scientists in the U.S. and Japan reported successfully reprogramming human skin cells to act like embryonic stem cells. • There is a catch. To reprogram the skin cells, the researchers had to use retroviruses as vectors to carry new genes into the cell nucleus. Once there, the retroviruses become part of the cell's genetic code. These retroviruses could cause deadly mutations or cancers in patients treated with the newly created stem cells.

11. 7-Have any diseases been cured with embryonic stem cells in people? • A. No. But in January 2009, Geron Corp. got approval to test embryonic stem cells in 10 patients paralyzed by spinal cord injury. • In November 2008, doctors in Europe performed the first trachea trcellsansplant that used the patient's own adult stem; no embryonic stem cells were used.

12. 8- Which diseases could be treated with stem cells? • Researchers are studying stem cells for conditions including: • Diabetes: • Stem cells could help make insulin-producing cells for diabetes patients. • Parkinson's disease: • Stem cells may be able to make new nerve cells in the brain to replace those destroyed by Parkinson's disease.

13. 8- Which diseases could be treated with stem cells? …. • Cancer: • Stem cells might help recreate bone marrow, make cells that could kill the cancer, and replace cancer-damaged tissue. • Spinal cord injury: Stem cells might be used to create new spinal cord cells to replace damaged cells • Heart disease: • After a heart attack, part of the heart muscle dies. Stem cells might be able to make heart muscle cells to replace the damaged part of the heart. • Crohn's disease: • Stem cells could replace the misguided immune cells that attack the digestive tract.

14. 8-Which diseases could be treated with stem cells? …. • Genetic diseases: • In many genetic diseases, there is a specific defect in the genes. Stem cells that do not have this defect could be used in their place.

15. 9-Are stem cell treatments safe? • That remains to be seen. • Cancer is one of the big concerns, partly because stem cells can go on dividing endlessly, which may lead to cancer. And, as noted earlier in this article, using retroviruses to "reprogram" adult cells to act like embryonic stem cells could pose a cancer risk. • Unfortunately, there is no way to know for sure without actually doing stem cell treatments. Researchers will be watching patients who receive stem cell treatments very closely to see what risks arise.

16. 10- What is somatic cell nuclear transfer (SCNT)? • Somatic cell nuclear transfer (SCNT) is a technique in which the nucleus of a somatic cell, that is any cell of the body apart from the sperm or egg, is transferred into an egg that has had its original nucleus removed. The egg now has the same DNA, or genetic material, as the donor somatic cell. Given the right signals, the egg can be coaxed into developing as if it had been fertilized. The egg would divide to form 2 cells, then 4 cells, then 8 cells and so on until the blastocyst is formed. Embryonic stem cells can be derived from this blastocyst to create cell lines that are genetically identical to the donor somatic cell.

17. 11. Why derive embryonic stem cell lines following somatic cell nuclear transfer (SCNT)? • The derivation of patient-specific human embryonic stem cell lines using this technique (see ‘What is somatic cell nuclear transfer?’) Firstly, these cells could provide a powerful new tool for studying the basis of human disease and for discovering new drugs. Secondly, the resulting embryonic stem cells could be developed into a needed cell type, and if transplanted into the original donor, would be recognized as 'self', thereby avoiding the problems of rejection and immunosuppression that occur with transplants from unrelated donors.

18. 12. Can induced pluripotent cells replace research on embryonic stem cells or somatic cell nuclear transfer? • No. The derivation of human induced pluripotent stem cells opens up exciting new areas of stem cell research, however, this technology is at a very early stage and many fundamental questions remain. While iPS cells and embryonic stem cells share many characteristics they are not identical. The similarities and differences are still being explored.

19. تا سال 2004 تقريبا 350 مريض پا ركينسوني تحت درمان با بافت مزانسفاليك جنيني انسان يا خوك قرار گرفته اند.در اين بيماران بافت ترانسپلنت شده باعث جذبفلورو دوپا دربيماران پاركينسوني در روش تصوير برداري PET شد.يك مشكل در پيوند اين ميباشد كه بقا سلولهاي ترانسپلنت شده كم ميباشد.وتنها 5 تا 20 درصد سلولها در محل ضايعه باقي ميمانند.در مدلهاي حيواني بقا سلولهاي ترانسپلنت شده با به كار بردن فاكتورهاي رشد و مواد آنتي اكسيدان افزايش يافته است

20. سلولهای بنيادی خون ساز

21. سلولهاي بنيادي بند ناف وسلولهاي بنيادي خارج جنينی

22. ديابت مطالعات مختلفي براي تمايز سلولهاي بنيادي مغز استخوان سلولهاس بنيادي جنيني سلولهاي بنيادي پانكراس بالغين سلولهاي بنيادي خون بند ناف به سمت سلولهاي توليد كننده انسولين صورت گرفته است.خصوصيات اين سلولهاي بنيادي نشان داد كه اين سلولهاي بنيادي قادر به پايين اوردن مقدار گلوكز خون ميباشند. مطالعات نشان داده است كه سلولهاي بنيادي كه از مجراي پانكراس بدست امده اند باعث پايين آوردن مقدار گلوكز خون در موشهاي ديابتي شده اند.

23. خواهشمند است کاربران محترم نظرات اصلاحی خود را به آدرس esfandiari@med.mui.ac.ir و یا شماره تلفکس7922517ارسال فرمایند.