Definition of Peripheral blood stem cell transplantation
Peripheral blood stem cell transplantation: A new
technique in which stem cells are obtained
from a patient's blood and used in bone marrow transplantation.
Stem cells are small, round cells with a squat nucleus and scant
surrounding cytoplasm. Although unremarkable in appearance, stem
cells can perform what have been called "acts of biological
resurrection." Whereas other types of cells in the body have a
limited lifespan and die after dividing their endowed number of
times, a stem cell can reproduce forever. The stem cell is immortal
(in cellular terms).
A stem cell can forgo immortality and turn into an ordinary blood
cell, a red blood cell (an erythrocyte), a white blood cell (a
leukocyte), or a large cell (a megakaryocyte) that fragments into the
platelets needed for blood to clot.
A limited number of stem cells can miraculously repopulate the
whole bone marrow, provide an endless supply of stem cells,
reconstitute the entire repertory of blood cells, and restore the
immune system.
To obtain the stem cells, the stem cells are lured out of the bone
marrow by a special regimen of drugs. The blood is then filtered
through a machine and the stem cells are skimmed off. The removal of
the cells is termed pheresis or apheresis (from the Greek
"aphairesis" for removal).
The stem cells then may be used right away for bone marrow
transplant or stored in liquid nitrogen until needed.
Before the transplant is done, the patient receives high-dose
chemotherapy and/or radiation therapy to destroy diseased cells (the
leukemic cells, lymphoma cells, solid tumor cells, the diseased
immune system cells in scleroderma, etc.) The stem cells are then
returned to the patient, where they can produce new blood and immune
cells and replace the cells destroyed by the treatment. The stem-cell
preparation is infused into a vein and, once there in the blood
stream, the stem cells act like homing pigeons and head straight for
the bone marrow space.
Last Editorial Review: 10/18/1998Common Misspellings: peripheral blod stem cell transplantation, peripheal blood stem cell transplantation, peripheal blod stem cell transplantation, periphial blood stem cell transplantation, periphial blod stem cell transplantation, perpheral blood stem cell transplantation, perpheral blod stem cell transplantation
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