Genetics as it applies to evolution, molecular biology, and medical aspects.
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I am an undergraduate student who recently appeared for Hannover Medical School Phd Entrance examination.
They asked many questions to test analytical abilities one of which was" How will you prove in vivo that a cell is stem cell" ? Though I have very less knowledge in this field I gave the following answer on which many of you may laugh.
I answered that , Since stem cells have characteristic property of multidifferentiating, it can be exploited to prove its stem cell-ness. Two factors- one which induces tumor for example, and other which makes an animal immune to a X pathogen, can both be injected into yolk sac or bone marrow. If the tumor developed and animal is protected against infection upon exposure to that X pathogen, we can say vaguely that it has stem cell properties as it was able to give rise to two types of different cells. Its a very general answer and do not include any technical know-how.. If any of you can make any suggestions I will be happy.
A stem cell has the potential to develop into different kind of cells depending on it's stage of differentiation and the signal it recieves. In vivo, a stem cell would definitely differentiate into it's neoghbouring defferentiated cells, if it still retains that potential (i.e if it has not differntiated past that stage).
stem cells are capable of even destroying HIV as far as i know.
they have the potential to differentiate into any of the organs present or even the organ-systems.
all they need is a hormonal or a neural message to do so.
dis reminds me of something. can we say that these cells are further, totipotent
Shaanu, stem cells are pluripotent i.e., they can give rise to all of the body cells derived from the three germ layers but it cant give rise to a new organism. They have varied uses these days in case of tissue loss or a very bad injury or a internal breakdown. But,the other side is VERY SCARY.
It has its own side effects which can outrule the advantages, in Stem cells can be very beneficial for treatments of many disorders and diseases, however they can also have no effect whatsoever if the disease is not caught early enough or if the patient doesn't meet certain requirements for a stem cells transplant. Immune suppression does not come from stem cells treatment, but from using radiation before the transplant in order to remove the "sick" cells and to make room for the healthy ones. Pluripotency in certain stem cells could also make it difficult to obtain a specific cell type.
Some stem cells form tumors when implanted in body, pluripotency is linked to tumor formation especially in embryonic stem cells, fetal proper stem cells, induced pluripotent stem cells. Fetal proper stem cells form tumors despite multipotency.
The human body attacks cells that come from non-self sources, and since most stem cell treatments come from non-self sources this could cause problems. Both adult and embryonic stem cells could differentiate into a cancerous form.
To avoid these problems:
Cells can be used from same patient that is being treated.
Extra-embryonic fetals stem cells and adult stem cells may not be rejected even if used from non-native source.
Makes it difficult to obtain exact cell type needed, because not all cells in a population differentiate uniformly. Undifferentiated cells can create tissues other than desired type serious cases.
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