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Medical Dictionary


protoplast (pro′to-plast)
1. Archaic term meaning the first individual of a type or race. 2. A bacterial cell from which the rigid cell wall has been completely removed; the bacterium loses its characteristic form. [proto- + G. plastos, formed]

protoporphyria (pro′to-por-fir′e-a)
Enhanced fecal excretion of protoporphyrin. erythropoietic p. [MIM*177000] a benign disorder of porphyrin metabolism due to a deficiency of ferrochelatase associated with enhanced fecal excretion of protoporphyrin, red-purple urine, and increased protoporphyrin IX in red blood cells, plasma, and feces; characterized by acute solar urticaria or more chronic solar eczema develops quickly on exposure to sunlight; autosomal dominant inheritance.

protoporphyrinogen type III (pro-to-por′fi-rin′o-jen)
The immediate precursor of protoporphyrin III in heme biosynthesis; elevated in cases of variegate porphyria. protoporphyrinogen type III oxidase a mitochondrial enzyme that uses O2 to convert protoporphyrinogen type III to protoporphyrin type III in heme biosynthesis; a deficiency of this enzyme is associated with variegate porphyria.

protoporphyrin type III (pro-to-por′fi-rin)
The principal protoporphyrin found in nature (one of 15 possible isomers), characterized by the presence of four methyl groups, two vinyl groups, and two propionic acid side chains; a porphyrin derivative that, with iron, forms the heme of hemoglobin and the prosthetic groups of myoglobin, catalase, cytochromes, etc.

protoproteose (pro-to-pro′te-os)
See primary proteose.

protosalt (pro′to-sawlt)
SYN: acid salt.

protospore (pro′to-spor)
The initial product of progressive cleavage, in which a multinucleate spore is produced. [proto- + G. sporos, seed]

protostoma (pro′to-sto′ma)
SYN: blastopore.

protostome (pro′to-stom)
SYN: blastopore. [proto- + G. stoma, mouth]

protosulfate (pro-to-sul′fat)
A compound of sulfuric acid with a protoxide of the metal.

prototaxic (pro-to-tak′sik)
In interpersonal psychiatry, a term referring to the earliest form of experience characteristic of the infant that is undifferentiated, global, and unorganized. [proto- + G. taxis, order, arrangement]

Prototheca (pro-to-the′ka)
A genus of an achlorophyllous alga; two species, P. zopfii and P. wickerhamii, cause protothecosis.

protothecosis (pro′to-the-ko′sis)
A rare verrucous cutaneous infection, olecranon bursitis, or disseminated disease caused by Prototheca zopfii and Prototheca wickerhamii.

prototroph (pro′to-trof, -trof)
A bacterial strain that has the same nutritional requirements as the wild-type strain from which it was derived. SEE ALSO: wild-type strain. [proto- + G. trophe, nourishment]

prototrophic (pro-to-trof′ik)
1. Pertaining to a prototroph. 2. Denoting the ability to undertake anabolism or to obtain nourishment from a single source, as with iron, sulfur, or nitrifying bacteria or photosynthesizing plants.

prototrophism (pro-to-trof-izm)
The property of being prototrophic.

prototype (pro′to-tip)
The primitive form; the first form to which subsequent individuals of the class or species conform. [proto- + G. typos, type]

protoveratrine A and B (pro-to-ver′a-tren)
A mixture of two alkaloids isolated from Veratrum album; they exert their main effect upon the cardiovascular system through the carotid sinus receptors and vagal sensory endings in the heart; they cause vasodilation and are thought to bring about a redistribution to all vascular beds and thus to induce a fall in blood pressure; used in certain forms of hypertension; the maleates have the same actions.

protovertebra (pro′to-ver′te-bra)
1. In the older literature, a somite. 2. More recently applied to the sclerotomal concentration that becomes the centrum of a vertebra. SYN: provertebra.

protovertebral (pro-to-ver′te-bral)
Relating to a protovertebra.

protoxide (pro-tok′sid)
SYN: suboxide.

Protozoa (pro-to-zo′a)
Formerly considered a phylum, now regarded as a subkingdom of the animal kingdom, including all of the so-called acellular or unicellular forms. They consist of a single functional cell unit or aggregation of nondifferentiated cells, loosely held together and not forming tissues, as distinguishes the Animalia or Metazoa, which include all other animals. P. were formerly divided into four classes: Sarcodina, Mastigophora, Sporozoa, and Ciliata; new classifications employ higher taxa (phyla, subphyla, and superclasses) and a number of major subdivisions. [proto- + G. zoon, animal]

protozoal (pro-to-zo′al)
SYN: protozoan (2) .

protozoan (pro-to-zo′an)
1. A member of the phylum Protozoa. SYN: protozoon. 2. Relating to protozoa. SYN: protozoal.

protozoiasis (pro′to-zo-i′a-sis)
Infection with protozoans.

protozoicide (pro-to-zo′i-sid)
An agent used to kill protozoa. [protozoa + L. caedo, to kill]

protozoologist (pro′to-zo-ol′o-jist)
A biologist who specializes in protozoology.

protozoology (pro′to-zo-ol′o-je)
The science concerned with all aspects of the biology and human interest in protozoa. [protozoa + G. logos, study]

protozoon, pl .protozoa (pro-to-zo′on, -zo′a)
SYN: protozoan (1) .

protozoophage (pro-to-zo′o-faj)
A phagocyte that ingests protozoa. [protozoa + G. phago, to eat]

protraction (pro-trak′shun)
In dentistry, the extension of teeth or other maxillary or mandibular structures into a position anterior to normal. [see protractor] mandibular p. a type of facial anomaly in which the gnathion lies anterior to the orbital plane. maxillary p. a type of facial anomaly in which the subnasion lies anterior to the orbital plane.

protractor (pro-trak′ter, -tor)
A muscle drawing a part forward, as antagonistic to a retractor; e.g., the serratus anterior muscle is a p. of the scapula; the lateral pterygoid muscle is a p. of the mandible. [L. pro-traho, pp. -tractus, to draw forth]

protriptyline hydrochloride (pro-trip′ti-len)
An antidepressant.

protrude (pro-trood′)
To thrust forward or project.

protrusio acetabuli (pro-troo′se-o as-e-tab′u-li)
SYN: Otto disease.

protrusion (pro-troo′zhun)
1. The state of being thrust forward or projected. 2. In dentistry, a position of the mandible forward from centric relation. [L. protrusio] bimaxillary p. the excessive forward projection of both the maxilla and the mandible in relation to the cranial base. SYN: double p.. bimaxillary dentoalveolar p. the positioning of the entire dentition forward with respect to the facial profile. double p. SYN: bimaxillary p..

protrypsin (pro-trip′sin)
SYN: trypsinogen.

protuberance (pro-too′ber-ans) [TA]
A swelling or knoblike outgrowth. A bulging, swelling, or protruding part. SEE ALSO: p.. SYN: protuberantia [TA] . [Mod. L. protuberantia] Bichat p. SYN: buccal fat-pad. external occipital p. [TA] a prominence about the center of the outer surface of the squamous portion of the occipital bone, giving attachment to the ligamentum nuchae. SYN: protuberantia occipitalis externa [TA] . internal occipital p. [TA] a projection from about the center of the cruciform eminence on the inner surface of the occipital bone. SYN: protuberantia occipitalis interna [TA] . mental p. [TA] the prominence of the chin at the anterior part of the mandible. SYN: protuberantia mentalis [TA] , mental process.

protuberantia (pro-too-ber-an′she-a) [TA]
SYN: protuberance. SEE ALSO: protuberance, prominence, eminence. [Mod. L. fr. protubero, to swell out, fr. tuber, a swelling] p. laryngea SYN: laryngeal prominence. p. mentalis [TA] SYN: mental protuberance. p. occipitalis externa [TA] SYN: external occipital protuberance. p. occipitalis interna [TA] SYN: internal occipital protuberance.

prourokinase (pro-ur-o-ki′nas)
The precursor of an activator of plasminogen, urokinase.

T., 19th century French physician. See P. space.

Louis J., French chemist, 1755–1826. See P. law.

provertebra (pro-ver′te-bra)
SYN: protovertebra.

Providencia (prov′i-den′se-a)
A genus of motile, peritrichous, nonsporeforming, aerobic or facultatively anaerobic bacteria (family Enterobacteriaceae) containing Gram-negative rods. These organisms do not hydrolyze urea or produce hydrogen sulfide; they produce indole and grow on Simmons citrate medium. They do not decarboxylate lysine, arginine, or ornithine. These organisms occur in specimens from extraintestinal sources, particularly urinary tract infections; they have also been isolated from small outbreaks and sporadic cases of diarrheal disease. The type species is P. alcalifaciens. P. alcalifaciens a bacterial species found in extraintestinal sources, particularly in urinary tract infections; it has also been isolated from small outbreaks and sporadic cases of diarrheal disease; it is the type species of the genus P.. P. rettgeri bacterial species that is found in chicken cholera and human gastroenteritis. SYN: Proteus rettgeri. P. stuartii a bacterial species isolated from urinary tract infections and from small outbreaks and sporadic cases of diarrheal disease.

provirus (pro-vi′rus)
The precursor of an animal virus, usually a retrovirus; theoretically analogous to the prophage in bacteria, the p. is integrated in the nucleus of infected cells, and can be activated in response to certain stimuli.

provitamin (pro-vi′ta-min)
A substance that can be converted into a vitamin; e.g., β-carotene. p. A trivial name for carotenoids exhibiting qualitatively the biologic activity of β-carotene, i.e., vitamin A precursors (α-, β-, and γ-carotene and cryptoxanthin); contained in fish liver oils, spinach, carrots, egg yolk, milk products, and other green leaf or yellow vegetables and fruits. p. D2 any substance that can give rise to ergocalciferol (vitamin D2); e.g., ergosterol. p. D3 SYN: 7-dehydrocholesterol.

Stanislas J.M. von, German protozoologist, 1876–1915. See Prowazekia, P. bodies, under body, P.-Greeff bodies, under body, Halberstaedter-P. bodies, under body.

Prowazekia (pro-va-ze′ke-a)
A genus of coprozoic flagellate protozoans, formerly part of the genus Bodo; the organisms may be parasitic but are not, so far as is known, pathogenic. [S. Prowazek]

Surname of a patient in whom the Stuart-P. factor was first discovered.

See proximo-.

proxemics (prok-sem′iks)
The scientific discipline concerned with the various aspects of urban overcrowding. [L. proximus, nearest, next]

See proximo-.

proximad (prok′si-mad)
In a direction toward a proximal part, or toward the center; not distad. [L. proximus, nearest, next, + ad, to]

proximal (prok′si-mal)
1. Nearest the trunk or the point of origin, said of part of a limb, of an artery or a nerve, etc., so situated. Toward the median plane following the curvature of the dental arch, in contrast to distal (2) . SYN: proximalis. 2. In dental anatomy, denoting the surface of a tooth in relation with its neighbor, whether mesial or distal, i.e., nearer to or farther from the anteroposterior median plane. SYN: mesial [TA] . [Mod. L. proximalis, fr. L. proximus, nearest, next]

proximalis (prok-si-ma′lis)
SYN: proximal (1) . [Mod. L.]

proximate (prok′si-mat)
Immediate; next; proximal.

proximo-, prox-, proxi-
Proximal. [L. proximus, nearest, next (to)]

proximoataxia (prok′si-mo-a-tak′se-a)
Ataxia or lack of muscular coordination in the proximal portions of the extremities, i.e., arms and forearms, thighs and legs. Cf.:acroataxia. [proximo- + ataxia]

proximobuccal (prok′si-mo-buk′al)
Relating to the proximal and buccal surfaces of a tooth; denoting the angle formed by their junction.

proximolabial (prok′si-mo-la′be-al)
Relating to the proximal and labial surfaces of a tooth; denoting the angle formed by their junction.

proximolingual (prok′si-mo-ling′gwal)
Relating to the proximal and lingual surfaces of a tooth; denoting the angle formed by their junction.

proxymetacaine hydrochloride (prok-si-met′a-kan)
SYN: proparacaine hydrochloride.

prozone (pro′zon)
In the case of agglutination and of precipitation, the phenomenon in which visible reaction does not occur in mixtures of specific antigen and antibody because of antibody excess. SYN: prezone.

prozygosis (pro-zi-go′sis)
SYN: syncephaly. [G. pro, before, + zygosis, a yoking]

Abbreviation for prion protein.

Abbreviation for 5-phospho-α-d-ribosyl-1-pyrophosphate.

PRPP synthetase
An enzyme that catalyzes the reaction of α-d-ribose 5-phosphate and ATP to produce PRPP and AMP; a regulatory enzyme in purine and pyrimidine biosynthesis; enhanced activity of this enzyme results in an increase in purine biosynthesis leading to gout.

prune (proon)
The dried ripe fruit of Prunus domestica (family Rosaceae), a tree cultivated in warm, temperate regions; a food with laxative properties.

Prunus (proo′nus)
A genus of trees (family Rosaceae) including the cherry, plum, peach, and apricot trees. [L. a plum-tree] P. serotina the wild black cherry; a botanical source of wild cherry. See P. virginiana. P. virginiana 1. wild black cherry bark, the bark of P. serotina, used as a tonic and in cough mixtures as a bronchial sedative; 2. the choke cherry; the chief substitute and adulterant of P. serotina.

prurigo (proo-ri′go)
A chronic disease of the skin marked by a persistent eruption of papules that itch intensely. [L. itch, fr. prurio, to itch] actinic p. SYN: p. aestivalis. p. aestivalis p. recurring each summer, becoming very severe as long as the hot weather continues. SYN: actinic p., summer p.. Besnier p. European term for p., possibly atopic. p. gestationis a pruritic papular skin disease occurring in pregnant women, without adversely affecting pregnancy or the fetus. Hebra p. a severe form of chronic dermatitis with secondary infection in which there are constantly recurring, intensely itchy papules and nodules, often associated with atopy. p. mitis a mild form of a chronic dermatitis characterized by recurring, intensely itching papules and nodules, probably atopic. p. nodularis an eruption of hard, dome-shaped nodules (Picker nodules) in the skin caused by rubbing and accompanied by intense itching; occasionally due to mycobacterial infection, the cause is usually unknown. p. simplex a mild form of p. having a pronounced tendency to relapse. summer p. SYN: p. aestivalis.

pruritic (proo-rit′ik)
Relating to pruritus.


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