Category: P
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Phage
A virus that attacks and destroys bacteria. Infective agents of virus type, which act as parasites living on bacteria, at whose expense they propagate causing the death of the invaded cell. Phages, which consist of deoxyribonucleic acid and specific proteins, possess a characteristic morphology when seen with the electron microscope, combined with a relative resistance…
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Peyronie’s disease
A condition, usually in men of middle age or older, in which the penis develops a fibrous ridge along its top or sides, causing a curvature during erection. A condition associated with Dupuytren’s contracture in which hard fibre develops in the penis which becomes painful when erect [Described 1743. After Frangois de la Peyronie (1678-1747),…
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Peyote
A small cactus plant found mainly in Mexico and in the Southwest United States. It has the generic name of Laphaphora williamsii and produces alkaloid mescaline that is extracted for its psychoactive effects. Cactus from which the hallucinogen mescaline is derived. The cactus plant, Lophophora williamsii, from which the hallucinogen mescaline is obtained. A cactus…
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Petty
Being overly concerned with unimportant details.
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Petting
Sexual activity that stops short of coitus.
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Pet scan
Position emission tomography. A brain imaging technique that uses a radioactive tracer to detect oxygen metabolism in various regions of the brain in order that levels of activity in these regions may be evaluated.
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Petrous
Rock-like. Like stone. Petrosal.
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Petit mal seizures
Associated with epilepsy and usually occur in childhood. They are characterized by a partial loss of consciousness, sometimes accompanied by muscular contractions lasting up to 30 s.
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Petit mal epilepsy
A type of epilepsy in which the person’s seizures are relatively brief and may alter or interrupt consciousness.
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Petitioner
The person who petitions a court. If the case is appealed, this person is referred to as appellant.