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H & E Stain
Hematoxylin and eosin stain (H&E stain or HE stain) is a popular staining method in histology.

Haploid
The number of chromosomes in a gamete of an organism, symbolized by n.A cell or an organism having half of the number of chromosomes in somatic cells.

Hematopoiesis
Hematopoiesis is the formation of blood cellular components.

Hematopoietic Stem Cell [HSC]
A stem cell that gives rise to all red and white blood cells and platelets.

Hematopoietic Cell Transplantation:
The transplantation of hematopoietic stem cells with blood-forming potential. Hematopoietic stem cells provide rapid and sustained reconstitution of blood formation and are found in adult bone marrow, umbilical cord blood, peripheral blood and in fetal liver.

Hepatocytes
Hepatocytes are cells of the liver. Hepatocytes secrete bile juice.

Histocompatible:
TA tissue or organ from a donor (the person giving the organ or tissue) that will not be rejected by the recipient (the patient in whom the tissue or organ is transplanted). Rejection is caused because the immune system of the recipient sees the transplanted organ or tissue as foreign and tries to destroy it. Tissues from most people are not histocompatible with other people. In siblings, the probability of histocompatibility is higher, while identical twins are almost always histocompatible.

Histocompatibility:
Is the property of having the same, or mostly the same, alleles of a set of genes called the major histocompatibility complex. These genes are expressed in most tissues as antigens, to which the immune system makes antibodies. The immune system at first makes antibodies to all sorts of antigens, including those it has never been exposed to, but stops making them to antigens present in the body. If the body is exposed to foreign antigens, as by getting a tissue graft, it attacks the foreign material unless it is histocompatible.

A similar system exists in many plants; its purpose is not to reject grafts but to prevent inbreeding. Pollen from a plant sharing a histocompatibility gene with the female either fails to grow or dies soon after germinating.

Homeostasis
Homeostasis, any self-regulating process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival.

Homologous:
Similar or uniform, often used in the context of genes and DNA sequences. In the context of stem cells, the term homologous recombination is a technique used to disable a gene in embryonic stem cells.

Homologous Recombination:
A technique used to inactivate a gene and determine its function in a living animal.

Human Embryonic Stem Cell (hESC):
A type of pluripotent stem cell derived from the inner cell mass (ICM) of the blastocyst.

Huntington’s Disease
Stem cells will one day be used in regenerative medicines to treat HD.

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