Glossary

biopsy – taking a small sample of body tissue for examination and testing in the laboratory.

codon – the word for the junction on genetic material (DNA or RNA) occupied by three nucleotides (or bases) to form an amino acid. In HIV it is most used when refering to drug resistance. There is an amino acid at each codon and the codons are numbered (starting from 1) for each section of the HIV gene. For example the mutation M184V in RT refers to a mutation change at codon 184 in the reverse transcriptase gene.

placenta – the placenta is a temporary organ that develops in pregnancy and joins the mother and foetus. The placenta acts as a filter. It transfers oxygen and nutrients from the mother to the foetus, and takes away carbon dioxide and waste products. The placenta is full of blood vessels.

The placenta is expelled from the mother’s body after the baby is born and it is no longer needed. It is sometimes called the afterbirth.

open label – this means that a patient in a trial knows which treatment they are taking.

HIV transmission is when the virus passes from one person to another. When this is from mother to baby it is called mother-to-child transmission (MTCT), perinatal or vertical transmission. Children who become HIV-positive in this way are called vertically infected children