| purine-free diet | A diet containing a minimal quantity of purine bases (meats); liver, kidney, and sweetbread especially are excluded and replaced by dairy products, fruits, and cereals; alcoholic beverages also are excluded. Synonym: purine-free diet. (05 Mar 2000) |
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| purine-nucleoside phosphorylase | <enzyme> An enzyme that catalyses the reaction between a purine nucleoside and orthophosphate to form a free purine plus ribose-5-phosphate. Chemical name: Purine-nucleoside:orthophosphate ribosyltransferase Registry number: EC 2.4.2.1 (12 Dec 1998) |
| purine-restricted diet | See: gout diet. (05 Mar 2000) |
| purinergic receptor | <biochemistry> Receptors that use purine nucleotides (e.g. ATP) as ligands. (18 Nov 1997) |
| purines | A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include adenine and guanine, constituents of nucleic acids, as well as many alkaloids such as caffeine and theophylline. Uric acid is the metabolic end product of purine metabolism. (12 Dec 1998) |
| purity | The condition of being pure. Specifically: Freedom from foreign admixture or deleterious matter; as, the purity of water, of wine, of drugs, of metals. Cleanness; freedom from foulness or dirt. "The purity of a linen vesture." . Freedom from guilt or the defilement of sin; innocence; chastity; as, purity of heart or of life. Freedom from any sinister or improper motives or views. Freedom from foreign idioms, or from barbarous or improper words or phrases; as, purity of style. Origin: OE. Purete, purte, OF. Purte, F. Purete, from L. Puritas, fr. Purus pure. See Pure. Source: Websters Dictionary (01 Mar 1998) |
| Purkinje cell | <neurology, pathology> A class of output neurons in the cerebellum, which are the only neurons that convey signals away from the cerebellum. They form a layer of large ganglion cells near the surface of the cerebellum. Origin: From J. E. Purkinje, their discoverer. (12 Dec 1998) |
| Purkinje conduction | <neurology, physiology> Conduction of the cardiac impulse through the Purkinje system. (05 Mar 2000) |
| Purkinje effect | <ophthalmology> In the light-adapted eye, the region of maximal brightness is in the yellow; in the dark-adapted eye, the region of maximal brightness is in the green. Synonym: Purkinje effect, Purkinje shift. (05 Mar 2000) |
| Purkinje fibre | <cardiology, pathology> A group of specialised cardiac muscle cells that conduct electrical impulses through the heart and are involved in regulating the heart beat. The fibres form the terminal portion of the heart conduction system and have central granulated protoplasm containing one or two nuclei and a transversely striated peripheral portion. They are the terminal ramifications of the conducting system of the heart found beneath the endocardium of the ventricles. See: conducting system of heart. (10 Jul 2002) |
| Purkinje images | <ophthalmology, physiology> The two images formed by the anterior and posterior surfaces of the cornea and the two images formed by the anterior and posterior surfaces of the lens. Synonym: catatropic image, Purkinje images, Sanson's images. (05 Mar 2000) |
| Purkinje shift | <ophthalmology> In the light-adapted eye, the region of maximal brightness is in the yellow; in the dark-adapted eye, the region of maximal brightness is in the green. Synonym: Purkinje effect, Purkinje shift. (05 Mar 2000) |
| Purkinje system | <cardiology, physiology> Terminal ramifications in the ventricles of the specialised conducting system of the heart. (05 Mar 2000) |
| Purkinje's cells | <neurology, pathology> A class of output neurons in the cerebellum, which are the only neurons that convey signals away from the cerebellum. They form a layer of large ganglion cells near the surface of the cerebellum. Origin: From J. E. Purkinje, their discoverer. (12 Dec 1998) |
| Purkinje's corpuscle | <neurology, pathology> A class of output neurons in the cerebellum, which are the only neurons that convey signals away from the cerebellum. They form a layer of large ganglion cells near the surface of the cerebellum. Origin: From J. E. Purkinje, their discoverer. (12 Dec 1998) |