2,3-Bisphosphoglycerate: An intermediate in the Rapoport–Luebering shunt, formed between 1,3-bisphosphoglycerate and 3-phospho-glycerate; an important regulator of the affinity of hemoglobin for oxygen.
5-α-reductase: Enzyme responsible for conversion of testosterone to its active metabolite dihydrotesterone. Two types of this enzyme exist. Type 2 is predominant in prostate cells.
α-Amino-3-hydroxy-5-methyl-4 isoxazolepropionate (AMPA)/kainate receptors: Two of three types of ionotropic post-synaptic glutamate receptors. These receptors are similar and are often considered together. Upon binding glutamate, these receptors permit the influx of Na+ ions and results in brain excitation. These are one of the two primary receptors for excitatory neurotransmission in the brain.
α-Amino-3-hydroxy-5-methylisoxazole-4-propionate: See AMPA.
α-Hydroxy acids: Exfoliating products such as lactic, glycolic, malic, mandelic, and tartaric acid used in cosmetics.
β-Hydroxy acid: Salicylic acid.
γ-Aminobutyric acid (GABA): The major inhibitory neurotransmitter in the central nervous system.
γ-Aminobutyric acid (GABAA) receptors: Postsynaptic ionotropic receptors that bind to GABA and result in Cl− influx and neuronal hyperpolarization. GABA is the main inhibitory neurotrasmitter in the brain and GABAA receptors mediate fast CNS inhibitory neurotransmission.
Abscess: A purulent collection of fluid separated from surrounding tissue by a wall comprised of inflammatory cells and adjacent organs. It usually contains necrotic debris, bacteria, and inflammatory cells.
Abstinence: Refraining from the indulgence in something, as sexual intercourse or substances, by one's own choice. The absence of genital contact that could permit a pregnancy (i.e., penile penetra-tion into the vagina).
Acanthosis: Increased thickness of the prickle cell layer of the skin.
Acculturation: The process by which individuals from one cultural group adopt or change behaviors, attitudes and/or beliefs through contact with a different culture.
Acetabular: Relating to the acetabulum, the hollow, cuplike portion of the pelvis into which the head of the thigh bone (femur) fits.
Achalasia: Problem that occurs when a ring of muscle fibers, such as a sphincter of the esophagus, fail to relax.
Acne: Inflammatory eruption of the sebaceous gland.
Acnegenicity: Product effect that causes irritation of follicles resulting in papules and pustules.
Acquired resistance: See Secondary resistance.
Acromegaly: A pathologic condition characterized by excessive production of growth hormone.
Activities of daily living: Dressing, bathing, getting around inside the home, feeding, toileting, and grooming. See also Instrumental activities of daily living.
Acute bacterial pharyngitis: Acute bacterial infection of the oropharynx or nasopharynx.
Acute bacterial sinusitis: Acute bacterial infection of the paranasal sinuses lasting less than 30 days.
Acute coronary syndrome (ACS): Ischemic chest discomfort at rest most often accompanied by ST-segment elevation, ST-segment depression, or T-wave inversion on the ...