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Medical Dictionary - Dictionary of Medicine and Human Biology


alimentation (al-i-men-ta′shun)
Providing nourishment. SEE ALSO: feeding. forced a. SYN: forced feeding. parenteral a. providing nourishment intravenously. rectal a. nourishment provided by retention enemas.

alinasal (al′i-na′sal)
Relating to the wings of the nose (alae nasi), or flaring portions of the nostrils. [L. ala, + nasus, nose]

alinement (a-lin′ment)
SYN: alignment.

alinjection (al′in-jek′shun)
Injection of alcohol for hardening and preserving pathologic and histologic specimens.

aliphatic (al-i-fat′ik)
Denoting the acyclic carbon compounds, most of which belong to the fatty acid series. [G. aleiphar (aleiphat-), fat, oil] a. acids the acids of nonaromatic hydrocarbons ( e.g., acetic, propionic, butyric acids); the so-called fatty acids of the formula R&cbond;COOH, where R is a nonaromatic (a.) hydrocarbon.

alipoid (a-lip′oyd)
Characterized by absence of lipoids. [G. a- priv. + lipoides, resembling fat]

alipotropic (a′lip-o-trop′ik)
Having no effect upon fat metabolism, or upon the movement of fat to the liver. [G. a- priv. + lipos, fat, + tropos, a turning]

aliquot (al′i-kwot)
In chemistry and immunology, pertaining to a portion of the whole; loosely, any one of two or more samples of something, of the same volume or weight. [L. a few, several]

alisphenoid (al-i-sfe′noyd)
Relating to the greater wing of the sphenoid bone. [L. ala, + sphen, wedge]

alizarin (a-liz′a-rin) [C.I. 58000]
1,2-Dihydroxyanthraquinone;a red dye that occurs in the root of madder (Rubia tinctorum and other Rubiaceae) in glucose combination (ruberythric acid) as orange needles, slightly soluble in water; used by the ancients as a dye. Now made synthetically from anthracene and used in the manufacture of dyes, e.g., a. blue, a. orange, “Turkey red.” As an indicator, it is yellow below pH 5.5 and red above pH 6.8; other modified alizarins have other colors and change color at other pH values. a. cyanin [C.I. 58610] disulfonate of hexahydroxyanthraquinone;an acid dye used as a nuclear stain after mordanting and as a fluorochrome in ultraviolet microscopy. a. purpurin SYN: purpurin (2) . a. red S [C.I. 58005] sodium a. sulfonate;used as a stain for calcium in bone (calcium appears red-orange, magnesium, aluminum, and barium are varying shades of red), in the determination of fluorine; as a pH indicator it changes from yellow to purple between pH 3.7 and 5.2.

alkadiene (al-ka-di′en)
An acyclic hydrocarbon (alkane) containing two double bonds.

alkalemia (al-ka-le′me-a)
A decrease in H-ion concentration of the blood or a rise in pH. [alkali + G. haima, blood]

alkali, pl .alkalies (al′ka-li)
1. A strongly basic substance yielding hydroxide ions (OH− in solution); e.g., sodium hydroxide, potassium hydroxide. 2. SYN: base (3) . 3. SYN: a. metal. [Ar., al, the, + qaliy, soda ash] caustic a. a highly ionized (in solution) a.; e.g., NaOH. fixed a. any a. other than a weakly ionized one, like ammonia. vegetable a. a mixture of potassium hydroxide and carbonate.

alkaline (al′ka-lin)
Relating to or having the reaction of an alkali.

alkalinity (al-ka-lin′i-te)
The state of being alkaline.

alkalinization (al′ka-lin-i-za′shun)
SYN: alkalization.

alkalinuria (al′ka-li-noo′re-a)
The passage of alkaline urine. SYN: alkaluria. [alkaline + G. ouron, urine]

alkalitherapy (al′ka-li-thar′a-pe)
Therapeutic use of alkali for local or systemic effect.

alkalization (al′kal-i-za′shun)
The process of rendering alkaline. SYN: alkalinization.

alkalizer (al′ka-liz-er)
An agent that neutralizes acids or renders a solution alkaline.

alkaloid (al′ka-loyd)
Originally, any one of hundreds of plant and fungal products distinguished by alkaline (basic) reactions, but now restricted to heterocyclic nitrogen-containing and often complex structures possessing pharmacologic activity; their trivial names usually end in -ine ( e.g., morphine, atropine, colchicine). Alkaloids are synthesized by plants and are found in the leaf, bark, seed, or other parts, usually constituting the active principle of the crude drug; they are a loosely defined group, but may be classified according to the chemical structure of their main nucleus. For medicinal purposes, due to improved water solubility, the salts of alkaloids ( e.g., morphine sulfate, codeine phosphate) are usually used. see also individual a. or a. class. SYN: vegetable base. ergot alkaloids (er′got) any of a large number of alkaloids obtained from the ergot fungus Claviceps purpurea or semisynthetically derived; examples include ergotamine, ergonovine, dihydroergotamine, lysergic acid diethylamide (LSD), methysergide. fixed a. a nonvolatile a.. Vinca alkaloids alkaloids such as vincristine and vinblastine (antitumor agents) extracted from the periwinkle plant. SYN: Catharanthus alkaloids.

alkalosis (al-ka-lo′sis)
A state characterized by a decrease in the hydrogen ion concentration of arterial blood below normal level, 40 nmol/L, or pH 7.4. The condition may be caused by an increase in the concentration of alkaline compounds, or by a decrease in the concentration of acidic compounds or carbon dioxide. acapnial a. SYN: respiratory a.. compensated a. a. in which there is a change in bicarbonate but the pH of body fluids approaches normal; respiratory a. may be compensated by increased production of metabolic acids or increased renal excretion of bicarbonate; metabolic a. is rarely compensated by hypoventilation. compensated metabolic a. retention of acid, primarily carbon dioxide by the lung and acid ions by the renal tubules, to reduce the effect on the pH of the blood of excess alkali produced by ingestion or metabolism of alkali-producing substances. compensated respiratory a. increased excretion of acid ions by the kidney to minimize the effect on the pH of the blood of excessive loss of carbon dioxide via the lungs, such as occurs with hyperventilation. metabolic a. an a. associated with an increased arterial plasma bicarbonate concentration, possibly resulting from an excessive intake of alkaline materials or an excessive loss of acid in the urine or through persistent vomiting; the base excess and standard bicarbonate are both elevated. SEE ALSO: compensated a.. respiratory a. a. resulting from abnormal loss of CO2 produced by hyperventilation, either active or passive, with concomitant reduction in arterial plasma bicarbonate concentration. SEE ALSO: compensated a.. SYN: acapnial a.. uncompensated a. a. in which the pH of body fluids is elevated because of lack of the compensatory mechanisms of compensated a..

alkalotic (al-ka-lot′ik)
Relating to alkalosis.

alkaluria (al-ka-loo′re-a)
SYN: alkalinuria.

alkane (al′kan)
The general term for a saturated acyclic hydrocarbon; e.g., propane, butane.

alkanet (al′ka-net) [C.I. 75530, 75520]
The root of an herb, Alkanna, or Anchusa tinctoria (family Boraginaceae), that yields red dyes alkannan and alkannin; used as a coloring agent; also used, combined with tannin, as an astringent.

alkannan (al′ka-nan) [C.I. 75520]
A minor red dye component derived from alkanet.

alkannin (al′ka-nin) [C.I. 75530]
The major red dye derived from alkanet; used as an astringent, and in cosmetics and foods; can be used as an indicator: red at pH 6.8, changing to purple at pH 8.8 and blue at pH 10.0; also used as a fat stain. SYN: anchusin.

alkapton (al-kap′ton)
SYN: homogentisic acid. [Boedeker's coinage fr. alkali + L + G. kapto, to suck up greedily]

alkatriene (al-ka-tri′en)
An acyclic hydrocarbon containing three double bonds; e.g., 2,4,6-octatriene, CH3&cbond;CH&dbond;CH&cbond;CH&dbond;CH&cbond;CH&dbond;CH&cbond;CH3.

alkavervir (al-ka-ver′vir)
A mixture of alkaloids obtained by the selective extraction of Veratrum viride with various organic solvents; used orally or parenterally as a hypotensive agent.

alkene (al′ken)
An acyclic hydrocarbon containing one or more double bonds; e.g., ethene, propene. SYN: olefin.

alkenyl (al′ken-il)
The radical of an alkene.

The radical of an alkene in which the double bond indicated by “en(e)” is between carbons 1 and 2 (carbon 1 being the radical or “yl” carbon), i.e., R&cbond;CH&dbond;CH&cbond;; sometimes expressed as alk-1-en-1-yl.

A phosphatidate in which at least one of the radicals attached to the glycerol is an alk-1-enyl rather than the usual acyl radical ( i.e., is derived from an aldehyde rather than an acid, hence the older trivial names phosphatidal and acetal phosphatid(at)e); “plasmenic acid” has been proposed as a name for such phosphatidates.

alkide (al′kid)
SYN: alkyl (2) .

alkyl (al′kil)
1. A hydrocarbon radical of the general formula CnH2n+1. 2. A compound, such as tetraethyl lead, in which a metal is combined with a. radicals. SYN: alkide. arylated a. SYN: aralkyl.

alkylamine (al-kil′a-men)
An alkane containing an &cbond;NH2 group in place of one H atom; e.g., ethylamine.

alkylation (al′ki-la′shun)
Substitution of an alkyl radical for a hydrogen atom; e.g., introduction of a side chain into an aromatic compound.

Abbreviation for acute lymphocytic leukemia.

allachesthesia (al′a-kes-the′ze-a)
A condition in which a tactile sensation is referred to a point other than that to which the stimulus is applied. SEE ALSO: allochiria. [G. allache, elsewhere, + aisthesis, sensation]

allanto-, allant-
Allantois; allantoid; sausage. [G. allas, allantos, sausage]

allantoate deiminase
An enzyme that catalyzes the conversion of allantoic acid to ureidoglycine, NH3, and CO2.

allantochorion (a-lan-to-kor′e-on)
Extraembryonic membrane formed by the fusion of the allantois and chorion.

allantogenesis (a-lan-to-jen′e-sis)
Formation and development of the allantois. [allanto- + G. genesis, origin]

allantoic (a-lan-to′ik)
Relating to the allantois.

allantoic acid (a-lan-to′ik as′id)
Diureidoacetic acid;a degradation product of allantoin. An important source of nitrogen in plants.

allantoid (a-lan′toyd)
1. Sausage-shaped. 2. Relating to, or resembling, the allantois. [allanto- + G. eidos, appearance]

allantoidoangiopagus (a-lan-toyd′o-an-je-op′a-gus)
SYN: omphaloangiopagus. See allantoidoangiopagous twins, under twin. [allantoid + G. angeion, vessel, + pagos, fastened]

allantoin (a-lan′to-in)
A substance present in allantoic fluid, fetal urine, and elsewhere; also an oxidation product of uric acid and the end product of purine metabolism in animals other than humans and the other primates. SYN: 3-ureidohydantoin, cordianine, glyoxyldiureide.

allantoinase (a-lan-to′i-nas)
An enzyme (an amidohydrolase) that catalyzes the hydrolysis of allantoin to allantoic acid.

allantoinuria (a-lan′to-in-u′re-a)
The urinary excretion of allantoin; normal in most mammals, abnormal in humans. [allantoin + G. ouron, urine]

allantois (a-lan′to-is)
A fetal membrane developing from the hindgut (or yolk sac, in humans). In humans it is vestigial; externally, in mammals, it contributes to the formation of the umbilical cord and placenta; in birds and reptiles, it lies close beneath the porous shell and serves as an organ of respiration. SYN: allantoid membrane. [allanto- + G. eidos, appearance]

allaxis (a-laks′is)
SYN: metamorphosis. [G. allattein, to alter]

allele (a-lel′)
Any one of a series of two or more different genes that may occupy the same locus on a specific chromosome. As autosomal chromosomes are paired, each autosomal gene is represented twice in normal somatic cells. If the same a. occupies both units of the locus, the individual or cell is homozygous for this a.. If the alleles are different, the individual or cell is heterozygous for both alleles. See DNA markers. SEE ALSO: dominance of traits. SYN: allelomorph. [G. allelon, reciprocally] codominant a. codominant. silent a. SYN: amorph.

allelic (a-le′lik)
Relating to an allele. SYN: allelomorphic.

allelism (al′e-lizm)
The state held in common by alleles. SYN: allelomorphism.

allelocatalysis (a-le′lo-ka-tal′i-sis)
Self-stimulation of growth in a bacterial culture by addition of similar cells. [G. allelon, mutually, reciprocally, + catalytikos, able to dissolve]

allelocatalytic (a-le′lo-kat-a-lit′ik)
Mutually catalytic; denoting two substances each of which is decomposed in the presence of the other.

allelochemicals (a-le′lo-kem′i-kalz)
Signal substances between individuals of different species. Cf.:pheromones. [G. allelon, reciprocally, + chemical]

allelomorph (a-le′lo-morf)
SYN: allele. [G. allelon, reciprocally, + morphe, shape]

allelomorphic (a-le-lo-mor′fik)
SYN: allelic.

allelomorphism (a-le-lo-mor′fizm)
SYN: allelism.

allelotaxis, allelotaxy (a-lel-o-taks′is, -taks′e)
Development of an organ from a number of embryonal structures or tissues. [G. allelon, reciprocally, + taxis, an arranging]

Willard Myron, U.S. gynecologist, *1904. See Corner-A. test, Corner-A. unit, A.-Masters syndrome.

Edgar Van Nuys, U.S. physician, 1900–1961. See A. test.

Alfred Henry, U.S. chemist, 1846–1904. See A. test.

Edgar, U.S. endocrinologist, 1892–1943. See A.-Doisy test, A.-Doisy unit.


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