A-: Prefix indicating the absence or depletion of something: for example, aphagia (not eating) or aphonia (voiceless). The related prefix an- is usually used before a vowel, as in anemia (without blood) and anoxia (without oxygen).
- ABO blood group
ABO blood group: The major human blood group system. The ABO type of a person depends on the presence or absence of two genes, A and B. These genes determine the configuration of the red blood cell surface. A person who has two A genes has red blood cells of type A. A person who […]
- Abortion, multiple
Abortion, multiple: Two or more miscarriages (spontaneous abortions) by a woman. Couples who have had multiple abortions have about a 5% chance that one member of the couple is carrying a chromosome translocation responsible for the miscarriages.
Abortion: In medicine, an abortion is the premature exit of the products of conception (the fetus, fetal membranes, and placenta) from the uterus. It is the loss of a pregnancy and does not refer to why that pregnancy was lost. A spontaneous abortion is the same as a miscarriage. The miscarriage of three or more […]
- Abortion, therapeutic
Abortion, therapeutic: An abortion that is brought about intentionally. Also called an artificial or induced abortion. As opposed to a spontaneous abortion (a miscarriage).
- A (adenine)
A (adenine): In genetics, A stands for adenine, one member of the A-T (adenine-thymine) base pair in DNA. The other base pair in DNA is G-C (guanine-cytosine). Each base pair forms a “rung of the DNA ladder.” A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule […]