A small proteinaceous infectious disease-causing agent that is believed to be the smallest infectious particle. A prion is neither bacterial nor fungal nor viral and contains no genetic material. Prions have been held responsible for a number of degenerative brain diseases, including mad cow disease, Creutzfeldt-Jakob disease, fatal familial insomnia, kuru, and an unusual form of hereditary dementia known as Gertsmann-Straeussler-Scheinker disease.
- Prion dementia
- Prior authorization
In pharmacy, a cost-containment procedure that requires a prescriber to obtain permission to prescibe a medication prior to prescribing it. Also called prior approval.
- Private mutation
A rare gene mutation that is usually found only in a single family or a small population. A private mutation occurs and is passed to a few family members, but not to future generations.
- PRK (photorefractive keratectomy)
A kind of laser eye surgery designed to change the shape of the cornea to eliminate (or reduce) the need for glasses and contact lenses. The laser is used to remove the outer layer of the cornea and flatten the cornea. The flattening of the cornea is intended to correct myopia (nearsightedness) and astigmatism (uneven […]
A combining form (from both Greek and Latin) with many meanings including “before, in front of, preceding, on behalf of, in place of, and the same as.” Used as a word, pro of course means professional and, in medicine, it is short for prothrombin.