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Monitoring Stem Cell Research 
Immunodeficient: Unable to develop a normal immune response to, 
for example, a foreign substance. 
Immunosuppressive drugs: Drugs that prevent or interfere with the 
development of an immunologic response. After a transplant, immu- 
nosuppressive drugs are usually necessary in order to prevent the 
recipient from rejecting the transplant. 
Implantation: The attachement of the blastocyst to the uterine lin- 
ing, and its subsequent embedding there. (Based on SMD) 
In vitro fertilization (IVF): The union of an egg and sperm, where 
the event takes place outside the body and in an artificial environ- 
ment (the literal meaning of “in vitro" is “in glass”; for example, in a 
test tube). (CR) 
Inner cell mass: The cluster of cells inside the blastocyst. These cells 
give rise to the embryonic disk of the later embryo and, ultimately, 
the fetus. (NIH) 
Karyotype: The chromosome characteristics (number, shape, etc) of 
an individual cell or cell line, usually presented as a systematized 
array in pairs. (SMD) 
Leukemia inhibitory factor: A cell messenger protein originally 
noted for inhibition of mouse Ml myeloid leukemia cells that also has 
effects including inhibiting differentiation to maintain stem cells. 
Lineage: The descendants of a common ancestor. 
Long-term self-renewal: The ability of stem cells to renew them- 
selves by dividing into the same non-specialized cell type over long 
periods (many months to years) depending on the specific type of 
stem cell. (NIH) 
Lymphocyte: A motile cell formed in tissues such as the lymph 
nodes, that functions in the development of immunity. 
Meiosis: A special process of cell division comprising two nuclear 
divisions in rapid succession that result in four cells (that will be- 
come gametes) with the haploid number of chromosomes. (Based on 
SMD) 
PRE -PUBLICATION VERSION 
