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Medical Dictionary


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pyramin, pyramine (pir′a-min)
SYN: toxopyrimidine.

pyramis, pl .pyramides (pir′a-mis, pi-ram′i-dez) [TA]
SYN: pyramid (1) . [Mod. L. fr. G. pyramid] p. medullae oblongatae [TA] SYN: pyramid of medulla oblongata. p. renalis, pl .pyramides renales SYN: renal pyramids, under pyramid. p. [TA] of cerebellum SYN: pyramid of vermis. p. tympani SYN: eminentia pyramidalis. p. vestibuli [TA] SYN: pyramid of vestibule.

pyran (pi′ran)
A cyclic compound that may be considered the formal parent of sugars with an oxygen bridge from carbon atoms 1–5 (the pyranoses).

pyranone (pir′a-non, pi′-)
SYN: pyrone.

pyranose (pir′a-nos, pi′-)
A cyclic form of a sugar in which the oxygen bridge forms a pyran.

pyrantel pamoate (pi-ran′tel)
An anthelmintic, especially useful drug for single or mixed intestinal nematode infections such as Ascaris, hookworm, pinworm, and Trichostrongylus species.

pyrathiazine hydrochloride (pir-a-thi′a-zen)
An antihistaminic.

pyrazinamide (pir-a-zin′a-mid)
First-line antituberculosis drug, particularly active against Mycobacterium tuberculosis in macrophages. Like all antituberculosis drugs, it must be given with other drugs to be effective in active disease. Its major toxicity is hepatic.

pyrazolone (pir-a-zo′lon)
A class of nonsteroidal anti-inflammatory agents used in the treatment of arthritic conditions; e.g., phenylbutazone.

pyrectic (pi-rek′tik)
SYN: febrile.

pyrenemia (pi-re-ne′me-a)
A condition characterized by the presence of nucleated red cells in the blood. [G. pyren, the pit of a fruit, + haima, blood]

Pyrenochaeta romeroi (pi′re-no-ke′ta ro′me-roy)
One of the numerous species of true fungi capable of causing mycetoma in humans.

pyrenoid (pi′re-noyd)
One of the minute luminous bodies sometimes visualized in the chromatophores of some protozoa, such as Euglena viridis. [G. pyren, pit of a fruit, + eidos, resemblance]

pyrethrins (pi-reth′rinz)
Insecticidal constituents of pyrethrum flowers.

pyrethroids
Synthetic pyrethrin derivatives that are used as insecticides; as a class these agents are less toxic to mammals than are other effective insecticides.

pyrethrolone (pi-reth′ro-lon)
2-Methyl-4-oxo-3-(2,4-pentanedienyl)-2-cyclopentenol, a constituent of the pyrethrins.

pyrethrum (pi-re′thrum)
The root of Anacyclus p. (family Compositae), a shrub native to Morocco; has been used as a sialogogue; its flowers are a source of pyrethrins. [G. pyrethron, feverfew, fr. pyr, fire, from the hot-tasting root]

pyretic (pi-ret′ik)
SYN: febrile. [G. pyretikos]

pyreto-
Fever. SEE ALSO: pyr-, pyro- (1) . [G. pyretos, fever, fr. pyr, fire]

pyretogen (pi-ret′o-jen)
Rarely used term for pyrogen. [pyreto- + G. -gen, producing]

pyretogenesis (pi′re-to-jen′e-sis, pir′e-to-)
Rarely used term for the origin and mode of production of fever. [pyreto- + G. genesis, origin]

pyretogenetic, pyretogenic (pi′re-to-je-net′ik, -jen′ik)
SYN: pyrogenic.

pyretogenous (pi-re-toj′e-nus)
SYN: pyrogenic.

pyretotherapy (pi′re-to-thar′a-pe)
1. Obsolete synonym for pyrotherapy. 2. Treatment of fever. SYN: artificial fever, induced fever. [pyreto- + G. therapeia, treatment]

pyrexia (pi-rek′se-a)
SYN: fever. [G. pyrexis, feverishness]

pyrexial (pi-rek′se-al)
Relating to fever.

pyrexiophobia (pi-rek′se-o-fo′be-a)
Morbid fear of fever. [G. pyrexis, feverishness, + phobos, fear]

pyribenzyl methyl sulfate (pir-i-ben′zil)
SYN: bevonium methyl sulfate.

pyridine (pir′i-den, -din)
C5H5N;a colorless volatile liquid of empyreumatic odor and burning taste, resulting from the dry distillation of organic matter containing nitrogen; used as an industrial solvent, in analytic chemistry, and for denaturing alcohol.

pyridinium
A breakdown product of bone collagen, excreted in urine, and assayed as a measure of osteoclast activity; increased in disease states such as Paget's disease, primary hyperparathyroidism, and osteoporosis.

pyridinoline
Hydroxypyridinium; a. breakdown product of bone collagen, assayed as is pyridinium (q.v.) to gauge osteoclastic activity.

pyridofylline (pir-i-dof′i-lin)
7-(2-Hydroxyethyl)theophylline hydrogen sulfate compound with pyridoxol; a coronary vasodilator.

pyridostigmine bromide (pir′i-do-stig′men)
A cholinesterase inhibitor useful in the treatment of myasthenia gravis and to reverse the neuromuscular block produced by curare and similar agents at the termination of a surgical procedure.

pyridoxal (pir′i-dok′sal)
The 4-aldehyde of pyridoxine, having a similar physiologic action. SEE ALSO: pyridoxine. p. kinase an enzyme that catalyzes the phosphorylation by ATP of p. to p. 5-phosphate and ADP, thus converting the nutrient to the active coenzyme. p. 5-phosphate (PLP) a coenzyme essential to many reactions in tissue, notably transaminations and amino acid decarboxylations.

pyridoxamine (pir-i-dok′sa-men)
The amine of pyridoxine (–CH2NH2 replacing –CH2OH at position 4), having a similar physiologic action. See pyridoxine. p. 5-phosphate the amine of pyridoxal 5-phosphate (&cbond;CH2NH2 replacing &cbond;CHO at position 4), it is the intermediate formed in many enzyme-catalyzed reactions that utilize pyridoxal 5-phosphate.

pyridoxamine-phosphate oxidase
An oxidoreductase catalyzing oxidative deamination of pyridoxamine 5-phosphate (with O2 and H2O) to form pyridoxal 5-phosphate, H2O2, and NH3.

4-pyridoxic acid (pir-i-dok′sik)
The principal product of the metabolism of pyridoxal (–COOH replaces –CHO at position 4), appearing in the urine.

pyridoxine (pir-i-dok′sen, -sin)
The original vitamin B6, which term now includes pyridoxal and pyridoxamine, associated with the utilization of unsaturated fatty acids. In rats, deficiency produces a nutritional dermatitis and acrodynia; in humans, deficiency may result in increased irritability, convulsions, and peripheral neuritis. The hydrochloride is used in pharmaceutic preparations; found in vegetables.

pyridoxine 4-dehydrogenase
An oxidoreductase catalyzing oxidation of pyridoxine with NADP+ to pyridoxal and NADPH.

pyriform (pir′i-form)
SYN: piriform. [L. pyrum (prop. pirum), pear, + forma, form]

pyrilamine maleate (pi-ril′a-men, pir′i-la-)
An antihistaminic. SYN: mepyramine maleate.

pyrimethamine (pir-i-meth′a-men)
A potent folic acid antagonist used as an antimalarial agent effective against Plasmodium falciparum; a valuable suppressant, active against the asexual erythrocytic and tissue forms; also used in the treatment of toxoplasmosis.

pyrimidine (Pyr) (pi-rim′i-den)
1,3-Diazine;a heterocyclic substance, the formal parent of several “bases” present in nucleic acids (uracil, thymine, cytosine) as well as of the barbiturates. p. 5′-nucleotidase an enzyme that catalyzes the hydrolysis of a p.-nucleoside 5′-monophosphate to produce orthophosphate and the p. nucleoside; a deficiency of this enzyme results in accumulation of p. nucleotides leading to hemolytic anemia. p. transferase SYN: thiamin pyridinylase.

pyrin
An abnormal neutrophil protein encoded by the MEFV gene in familial Mediterranean fever. SYN: marenostrin.

pyrithiamin (pir′i-thi′a-min)
A thiamin antimetabolite, differing from thiamin in that the thiazole ring of the thiamin molecule is replaced by a pyridine ring. SYN: neopyrithiamin.

pyro-
1. Combining form denoting fire, heat, or fever. SEE ALSO: pyr-, pyreto-. 2. In chemistry, combining form denoting derivatives formed by removal of water (usually by heat) to form anhydrides. SEE ALSO: anhydro-. [G. pyr, fire]

pyroboric acid (pi-ro-bor′ik)
SYN: tetraboric acid.

pyrocalciferol (pi′ro-kal-sif′er-ol)
A thermal decomposition product of calciferol.

pyrocatechase (pi-ro-kat′e-kas)
SYN: catechol 1,2-dioxygenase.

pyrocatechin (pi-ro-kat′e-kin)
SYN: pyrocatechol.

pyrocatechol (pi-ro-kat′e-kol)
1,2-Benzenediol;a constituent of the catecholamines, epinephrine and norepinephrine, and dopa; used externally as an antiseptic. SYN: catechol (1) , pyrocatechin.

pyrogallic acid (pi-ro-gal′ik)
SYN: pyrogallol.

pyrogallol (pi-ro-gal′ol)
Used externally in the treatment of psoriasis, ringworm, and other skin affections. SYN: pyrogallic acid.

pyrogallolphthalein (pi′ro-gal-o-thal′e-in, -thal′e-in)
SYN: gallein.

pyrogen (pi′ro-jen)
A fever-inducing agent; pyrogens are produced by bacteria, molds, viruses, and yeasts. [pyro- + G. -gen, producing] endogenous p. (EP) proteins that induce fever. Several (about 11) have been identified, including cytokines formed by components of the immune system, especially macrophages ( e.g., interleukins 1 and 6, interferons and tumor necrosis factors). SYN: leukocytic pyrogens. exogenous pyrogens drugs or substances that are formed by microorganisms and induce fever. Among the latter are lipopolysaccharides and lipoteichoic acid. leukocytic pyrogens SYN: endogenous p..

pyrogenic (pi-ro-jen′ik)
Causing fever. SEE ALSO: febrifacient. SYN: pyretogenetic, pyretogenic, pyretogenous.

pyroglobulins (pi-ro-glob′u-linz)
Serum proteins (immunoglobulins), usually associated with multiple myeloma or macroglobulinemia, which precipitate irreversibly when heated to 56°C.

pyroglutamic acid (Pyr) (pi′ro-gloo-ta′mik)
SYN: 5-oxoproline.

pyroligneous (pi-ro-lig′ne-us)
Relating to or produced by the dry distillation of wood. [pyro- + L. lignum, wood]

pyrolysis (pi-rol′i-sis)
Decomposition of a substance by heat. [pyro- + G. lysis, dissolution]

pyromania (pi-ro-ma′ne-a)
A morbid impulse to set fires. SYN: incendiarism. [pyro- + G. mania, frenzy]

pyromaniac (pi-ro-ma′ne-ak)
One affected with pyromania; arsonist.

pyromen (pi′ro-men)
SYN: piromen.

pyrometer (pi-rom′e-ter)
An instrument for measuring very high degrees of heat, beyond the capacity of a mercury or gas thermometer. [pyro- + G. metron, measure] resistance p. SYN: resistance thermometer.

pyrone (pi′ron)
A keto derivative of pyran. SYN: pyranone.

pyronin (pi′ro-nin)
A fluorescent red basic xanthene dye, the chloride of tetramethyldiaminoxanthene, p. Y or p. G (C.I. 45005), or of tetraethyldiaminoxanthene, p. B (C.I. 45010). These dyes, especially p. Y, are used in combination with methyl green for differential staining of RNA (red) and DNA (green); difference in staining result is probably due to the higher degree of polymerization of DNA; p. Y is also used as a tracking dye for RNA in electrophoresis.

pyroninophilia (pi′ro-nin-o-fil′e-a)
An affinity for the basic pyronin dyes; a useful indicator of intense protein synthesis accompanying RNA synthesis, as in the cytoplasm of an active plasma cell. [pyronin + G. philos, fond]

pyrophobia (pi-ro-fo′be-a)
Morbid dread of fire. [pyro- + G. phobos, fear]

pyrophosphatase (pi-ro-fos′fa-tas)
Any enzyme cleaving a pyrophosphate bond between two phosphoric groups, leaving one on each of the two fragments; e.g., inorganic p., NAD+ p. (cleaves NAD, etc., to mononucleotides), ATP p. (cleaves inorganic pyrophosphate from ATP, leaving AMP). SEE ALSO: flavin adenine dinucleotide. SYN: diphosphatase. inorganic p. a phosphohydrolase catalyzing hydrolysis of inorganic pyrophosphate to two orthophosphates. SYN: inorganic diphosphatase.

pyrophosphate (PP, PPi) (pi-ro-fos′fat)
A salt of pyrophosphoric acid; accumulates in cases of hypophosphatasia; sometimes referred to as inorganic p. (PPi). SYN: diphosphate. 99mTc p. a radionuclide tracer used for imaging ischemic myocardium in nuclear medicine. See technetium-99m.




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