class I (HLA-A,B,Cw), class II (HLA-DR,DQ,DP) and class III (no HLA genes).
The need for HLA matching depends on the type of transplant. In bone marrow transplantation, HLA matching is an absolute necessity, lest the cells be rejected. In corneal transplantation, HLA matching is less relevant because of the lack of blood vessels in the cornea and the “immunological privilege” of the cornea. HLA matching is not crucial but is beneficial to the success of most solid organ transplantation including kidney, liver, heart, lung, pancreas, and intestine.
- Transplantation, peripheral blood stem cell
A 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 […]
- Transport defect
Within the body, many molecules are able to pass across the membranes that surround cells. These molecules can accomplish this feat due to specific transport systems. These systems include special receptors on the membrane of the cell and special carrier proteins. The receptor recognizes the molecule and receives it on the cell membrane. Then the […]
- Transport disease, cystine
Commonly known as cystinuria, this is an inherited (genetic) disorder of the transport of an amino acid (a building block of protein) called cystine. The result is an excess of cystine in the urine (cystinuria) and the formation of cystine stones.
- Transposition, genetics
The ability of genes to change position on chromosomes, a process in which a transposable element is removed from one site and inserted into a second site in the DNA. Genetic transposition was the first type of genetic instability to be discovered. This remarkable phenomenon was discovered by the great American geneticist Barbara McClintock (1902-1992) […]
A short mobile DNA sequence that can replicate and of which copies can be inserted at random sites within chromosomes. A transposon has almost identical sequences at each end and inverted repeat sequences (that run in the opposite direction). It codes for the enzyme, transposase, that catalyses its insert in the chromosome.