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Medical Dictionary


alloploid (al′o-ployd)
Relating to a hybrid individual or cell with two or more sets of chromosomes derived from two different ancestral species; depending on the number of multiples of haploid sets, alloploids are referred to as allodiploids, allotriploids, allotetraploids, allopentaploids, allohexaploids, etc. SEE ALSO: heterokaryon. [allo- + -ploid]

alloploidy (al-o-ploy′de)
The condition of being alloploid.

allopolyploid (al-o-pol′i-ployd)
An alloploid having three or more haploid sets of chromosomes. [allo- + polyploid]

allopolyploidy (al-o-pol′i-ploy-de)
The condition of being allopolyploid.

allopregnane (al-o-preg′nan)
Original name for 5α-pregnane. See pregnane.

α-allopregnanediol (al′o-preg-nan-di′ol)
5α-Pregnane-3α,20α-diol;a metabolite of progesterone and adrenocortical hormones, found in urine.

allopsychic (al-o-si′kik)
Denoting the mental processes in their relation to the outer world. [allo- + G. psyche, mind]

allopurinol (al-o-pu′ri-nol)
Inhibitor of xanthine oxidase to inhibit uric acid formation; used in the treatment of gout and to retard the rapid metabolic degradation of 6-mercaptopurine.

allorhythmia (al-o-rith′me-a)
An irregularity in the cardiac rhythm that repeats itself any number of times. [allo- + G. rhythmos, rhythm]

allorhythmic (al-o-rith′mik)
Relating to or characterized by allorhythmia.

allose (al′os)
C6H12O6;an aldohexose. d-A. is epimeric with d-glucose.

allosensitization (al′o-sen′si-ti-za-shun)
Exposure to an alloantigen that induces immunologic memory cells.

allosome (al′o-som)
Obsolete term for one of the chromosomes differing in appearance or behavior from the autosomes and sometimes unequally distributed among the germ cells. [allo- + G. soma, body] paired a. SYN: diplosome. unpaired a. SYN: accessory chromosome.

allosteric (al-o-star′ik)
Pertaining to or characterized by allosterism.

allosterism, allostery (a-los′ter-izm, -los′ter-e)
The influencing of an enzyme activity, or the binding of a ligand to a protein, by a change in the conformation of the protein, brought about by the binding of a substrate or other effector at a site (allosteric site) other than the active site of the protein. Cf.:cooperativity, hysteresis.

allotetraploid (al-o-tet′ra-ployd)
See alloploid. [allo- + tetraploid]

allotherm (al′o-therm)
SYN: poikilotherm. [allo- + G. therme, heat]

allothreonines (aThr) (al-o-thre′o-nenz)
Two of the four diastereoisomers of threonine, differing from the l- and d-threonines in the configuration of the hydroxyl group in the side chain.

allotope (al′o-top)
The antigenic determinant on the constant or nonvariable region of an allotype. [allo- + -tope]

allotopia (al-o-to′pe-a)
SYN: dystopia. [allo- + G. topos, place]

allotransplantation (al′o-tranz-plan-ta′shun)
Transplantation of an allograft. SYN: homotransplantation.

allotriodontia (al-ot′re-o-don′she-a)
1. Growth of a tooth in some abnormal location. 2. Transplantation of teeth. [G. allotrios, foreign, + odous (odont-), tooth]

allotriosmia (al-ot-re-oz′me-a)
Incorrect recognition of odors. SYN: heterosmia. [G. allotrios, foreign, + osme, smell]

allotriploid (al-o-trip′loyd)
See alloploid. [allo + triploid]

allotrope (al′o-trop)
An element in one of the allotropic forms that it may assume. [allo- + G. tropos, a turning]

allotrophic (al-o-tro′fik)
Having an altered nutritive value. [allo- + G. trophe, nourishment]

allotropic (al-o-trop′ik)
1. Relating to allotropism. 2. Denoting a type of personality characterized by a preoccupation with the reactions of others.

allotropism, allotropy (a-lot′ro-pizm, -lot′ro-pe)
The existence of certain elements, in several forms differing in physical properties; e.g., carbon black, graphite, and diamond are all pure carbon. [allo- + G. tropos, a turning]

allotype (al′o-tip)
Any one of the genetically determined antigenic differences within a given class of immunoglobulin that occur among members of the same species. SEE ALSO: antibody. SYN: allotypic marker. [allo- + G. typos, model] Gm allotypes (al′lo-tips) refers to human immunoglobulin gamma heavy chains that express different Gm allotypic determinants (antigens). Each of the 25 different Gm allotypes is the product of genes within the constant regions of the human gamma heavy chain. InV allotypes (al′lo-tips) SYN: Km allotypes. Km allotypes (al′lo-tip) refers to human kappa immunoglobulin light chains that express different Km allotypic determinants (antigens). SYN: InV allotypes.

allotypic (al-o-tip′ik)
Pertaining to an allotype.

allowance (a′lau-antz)
1. Permission. 2. A portion allotted. recommended daily a. (RDA) the amount of daily nutrient intake judged to be adequate for the maintenance of good nutrition in an average adult.

alloxan (a-loks′-an)
An oxidation product of uric acid, 2,4,5,6-pyrimidinetetrone; administration to experimental animals causes hypoglycemia due to insulin liberation, followed by hyperglycemia due to destruction of the islets of Langerhans (a. diabetes).

alloxantin (a-loks′an-tin)
A condensation product of two molecules of alloxan, formed in the presence of reducing agents; a diabetogenic. SYN: uroxin.

alloxuremia (al-oks-u-re′me-a, al-ok-soo-re′me-a)
The presence of purine bases in the blood. [alloxan + G. haima, blood]

alloxuria (al-oks-u′re-a, al-ok-soo′re-a)
The presence of purine bodies in the urine. [alloxan + G. ouron, urine]

alloy (al′oy)
A substance composed of a mixture of two or more metals. chrome-cobalt alloys alloys of cobalt and chromium containing molybdenum and/or tungsten plus trace elements; used in dentistry for denture bases and frameworks, and other structures. eutectic a. an a., generally brittle and subject to tarnish and corrosion, with a fusion temperature lower than that of any of its components; used in dentistry mainly in solders. gold a. an a. whose principal ingredient is gold, usually contains copper or platinum and silver; used in dentistry for restorations requiring considerable strength. Raney a. an a. of Ni and Al in equal proportions, used in the preparation of Raney Nickel. silver-tin a. any a. of silver and tin; commonly 3 parts Ag and 1 part Sn, forming Ag3Sn, the chief intermetallic compound in dental amalgam.

The orange retinaldehyde resulting from the action of light on the rhodopsin of the retina, which converts the 11-cis-retinal component of the rhodopsin to all-a.retinal plus opsin. SYN: a.retinal, visual yellow.

allspice oil (awl′spis)
SYN: pimenta oil.

allyl (al′il)
The monovalent radical, CH2&dbond;CHCH2&cbond;. a. alcohol a colorless liquid of pungent odor used in making resins and plasticizers; highly irritating to mucous membranes and readily absorbed, causing depression and coma. SYN: vinyl carbinol. a. cyanide found in some mustard oils. a. isothiocyanate obtained from Brassica nigra by the action of water on sinigrin and myrosin or produced synthetically; a vesicant, used in 10% solution in 50% alcohol as a counterirritant in neuralgia. Gives mustard its characteristic flavor and aroma. SEE ALSO: mustard oil. SYN: volatile mustard oil. a. sulfide a constituent of garlic oil used in the manufacture of flavors.

allylamine (al-il-am′en)
A colorless liquid derived from crude oil of mustard and used in the pharmaceutical industry, e.g., in the manufacture of mercurial diuretics.

allylestrenol (al-il-es′tre-nol)
A progestational agent.

allylmercaptomethylpenicillin (al′il-mer-kap′to-meth′il-pen-i-sil′in)
SYN: penicillin O.

allysines (al′i-senz)
Two or more six-carbon α-amino acids connected by a carbon-carbon bond; constituents of connective tissue and other structural elements. SEE ALSO: desmin.

Floriano Paulo de, Brazilian physician, *1898. See A. disease, Lutz-Splendore-A. disease.

August Teodor, Swedish physiologist, 1833–1903. See A. test for blood.

almond oil (aw′mund, awl′mund)
A fixed oil expressed from sweet almonds, the kernels of varieties of Prunus amygdalus; used in ointments. bitter almond oil a volatile oil from the dried ripe kernels of bitter almonds and from other kernels containing amygdalin; it contains between 2 and 4% of hydrocyanic acid and 95% of benzaldehyde.

aloe (al′o)
1. The dried juice from the leaves of plants of the genus A. (family Liliaceae), from which are derived aloin, resin, emodin, and volatile oils. 2. The dried juice from the leaves of A. perryi (socotrine aloes), of A. barbadensis (Barbados and Curaçao aloes), or of A. capensis (Cape aloes); used as a purgative; used topically in cosmetics where it has no demonstrated value.

aloe-emodin (al′o-em′o-din)
The trimethyl ether of emodin; used as a laxative. See aloin, emodin. SYN: rhabarberone.

aloetin (al-o-e′tin)
SYN: aloin.

alogia (a-lo′je-a)
1. SYN: aphasia. 2. Inability to speak due to mental deficiency or an episode of dementia. [G. a- priv. + logos, speech]

aloin (al′o-in)
A yellow crystalline principle made up of aloe-emodin and glucose, obtained from aloe; used as a laxative. SYN: aloetin, barbaloin.

alopecia (al-o-pe′she-a)
Absence or loss of hair. SYN: baldness, calvities, pelade. [G. alopekia, a disease like fox mange, fr. alopex, a fox] a. adnata underdevelopment of the lashes. SEE ALSO: a. congenitalis, milphosis. SYN: madarosis (2) . androgenic a. gradual decrease of scalp hair density in adults with transformation of terminal to vellus hairs, which become lost as a result of familial increased susceptibility of hair follicles to androgen secretion following puberty. Two areas of the scalp are commonly affected in men; when it occurs in females it is associated with other evidence of excessive androgen activity, such as hirsutism. Autosomal dominant inheritance. See female pattern a., male pattern a.. SYN: common baldness. a. areata [MIM*104000] a common condition of undetermined etiology characterized by circumscribed, nonscarring, usually asymmetrical areas of baldness on the scalp, eyebrows, and bearded portion of the face. Hairy skin anywhere on the body may be affected; occasionally follows autosomal dominant inheritance. Peribulbar lymphocytic infiltration and association with autoimmune disorders suggest an autoimmune etiology. Slow enlargement with eventual regrowth within 1 year is common, but relapse is frequent and progression to a. totalis may occur, especially with childhood onset. a. capitis totalis SYN: a. totalis. cicatricial a. SYN: scarring a.. [L. cicatrix, cicatricis, scar + suffix -al, characterized by] a. congenitalis absence of all hair at birth. May be associated with psychomotor epilepsy [MIM*104130]; autosomal dominant or X-linked [MIM*300042] inheritance. SYN: congenital baldness, hypotrichiasis (2) . congenital sutural a. obsolete term for dyscephalia mandibulo-oculofacialis. female pattern a. diffuse partial hair loss in the centroparietal area of the scalp, with preservation of the frontal and temporal hairlines; the most frequent type of androgenic a. in women. a. hereditaria SYN: male pattern a.. a. leprotica thinning or total loss of the lateral third of the eyebrows, eyelashes, and body hairs, seen in leprosy; loss of scalp hair is rare. a. liminaris frontalis SYN: a. marginalis. lipedematous a. a. with itching, soreness, or tenderness of the scalp in black women; the scalp is thickened and soft, subcutaneous fat is increased, and the hair is sparse and short. male pattern a. [MIM*109200] the most common form of androgenic a., seen in men as receding frontal and bilateral triangular temple hairlines, and a balding patch on the vertex, which may progress to complete a.; inheritance is autosomal dominant in males, recessive in females. SYN: a. hereditaria, male pattern baldness, patterned a.. a. marginalis hair loss at the hairline, a condition most commonly seen in blacks; commonly transient and caused by chronic traction, although long-continued traction may cause permanent a.. SYN: a. liminaris frontalis. a. medicamentosa diffuse hair loss, most notably of the scalp, caused by administration of various types of drugs. moth-eaten a. patchy hair loss of parietal and occipital regions of the scalp, characteristic of secondary syphilis. a. mucinosa follicular mucinosis with a. appearing in areas of erythema and edema in the bearded portion of the face or in the scalp. patterned a. SYN: male pattern a.. postoperative pressure a. SYN: pressure a.. postpartum a. temporary diffuse telogen loss of scalp hair at the termination of pregnancy. premature a., a. prematura male pattern baldness appearing at an unusually early age. a. presenilis ordinary or common baldness occurring in early or middle life without any apparent disease of the scalp. pressure a. loss of hair over a circumscribed area usually on the posterior scalp, resulting from the continuous pressure on the occiput in a lengthy operative procedure, or unconsciousness following a drug overdose. SYN: postoperative pressure a.. scarring a. a. in which hair follicles are irreversibly destroyed by scarring processes including trauma, burns, lupus erythematosus, lichen planopilaris, scleroderma, folliculitis decalvans, or of uncertain cause (pseudopelade). SYN: cicatricial a.. a. senilis the normal loss of scalp hair in old age. a. symptomatica a. occurring in the course of various constitutional or local diseases, or following prolonged febrile illness. a. syphilitica moth-eaten a. of secondary syphilis. a. totalis total loss of hair of the scalp either within a very short period of time or from progression of localized a., especially a. areata. Cf.:a. universalis. SYN: a. capitis totalis. a. toxica hair loss attributed to febrile illness. traction a. circumscribed or diffuse loss of hair resulting from repetitive traction on the hair by pulling or twisting; also occurs after excessive application of hair “softeners” such as permanent wave solutions or hot combs. A. marginalis is a form of traction a.. SYN: traumatic a.. traumatic a. SYN: traction a.. a. triangularis (tri′ang-oo-la-ris) bilateral receding temporal hair lines in male pattern a.. a. triangularis congenitalis a congenital triangular patch of baldness on the frontal or temporal region of the scalp. a. universalis total loss of hair from all parts of the body. Cf.:a. totalis.

alopecic (al-o-pe′sik)
Relating to alopecia.

Bernard J., U.S. neurologist, 1900–1981. See A. disease.

alpha (al′fa)
First letter of the Greek alphabet, &a.;.

alpha amylase
A starch-splitting enzyme obtained from a nonpathogenic bacterium of the Bacillus subtilis class, used in the treatment of inflammatory conditions and edema of soft tissues associated with traumatic injury; its therapeutic usefulness has not been fully established and its mode of action is not known.

alpha-blocker (al′fa-blok′er)
SYN: α-adrenergic blocking agent.

alphadione (al-fa-di′on)
An intravenous anesthetic containing two steroids, alfaxalone, and alfadolone acetate, dissolved in 20% polyoxyethylated castor oil.

Alphaherpesvirinae (al′fa-her′pez-vir′i-ne)
A subfamily of Herpesviridae containing Simplexvirus and Varicellavirus.

alphaprodine (al-fa-pro′den)
A narcotic analgesic related to meperidine; physical and psychic dependence may develop.

alphasone acetophenide (al′fa-son)
SYN: algestone acetophenide.

Alphavirus (al′fa-vi-rus)
One of the genera of the family Togaviridae that was formerly classified as part of the “group A” arboviruses and includes the viruses that cause eastern equine, western equine, and Venezuelan encephalitis.

alpidem (al-pi′dem)
A benzodiazepine anxiolytic/sedative/hypnotic.

Arthur Cecil, South African physician, 1880–1959. See A. syndrome.


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