Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary
Category: Health and Medicine > Medical Dictionary
Date & country: He/al/th a, US
Words: 39130

alkali reserve
the ability of the combined buffer systems of the blood to neutralize acid. The pH of the blood normally is slightly on the alkaline side, between 7.35 and 7.45. Since the principal buffer in the blood is bicarbonate, the alkali reserve essentially is represented by the plasma bicarbonate concentration. However, hemoglobi...

alkali-ash diet
a therapeutic diet prescribed to increase the alkalinity of the urine and dissolve uric acid and cystine urinary calculi. This type of diet changes the urinary pH so that certain salts are kept in solution and excreted in the urine. Emphasis is placed on fruits, vegetables, and milk. Meat, eggs, bread, and cereals are res...

(al´kә-līn) (-lin) having the reactions of an alkali. having a pH greater than 7.0. alkaline phosphatase an enzyme localized on cell membranes that hydrolyzes phosphate esters liberating inorganic phosphate and has an optimal pH of about ...

(al″kә-lin´ĭ-te) the quality of being alkaline. the combining power of a base, expressed as the maximum number of equivalents of acid with which it reacts to form a salt.

(al″kә-lĭ-nu´re-ә) an alkaline condition of the urine.

(al″kә-li-za´shәn) the act of making alkaline.

(al´kә-li″zәr) an agent that causes alkalization.

(al´kә-loid″) one of a large group of organic, basic substances found in plants. They are usually bitter in taste and are characterized by powerful physiologic activity. Examples are morphine, cocaine, atropine, quinine, nicotine, and caffeine. The term is also applied to synthetic substances that have...

(al″kә-lo´sis) a pathologic condition caused by excessive base in the body, including loss of acid without comparable loss of base in the body fluids; there is a decrease in hydrogen ion concentration (increase in pH). Alkalosis is the opposite of acidosis. See also acid-base balance. adj., alkalot´ic., adj.

(al´kān) a saturated hydrocarbon (one without carbon-carbon multiple bonds).

(al-kap″to-nu´re-ә) an autosomal recessive aminoacidopathy characterized by accumulation of homogentisic acid. It is manifested by elevated concentrations of homogentisic acid in the urine (which darkens on standing or with alkalinization), a peculiar discoloration of body tissues known as ochronosis, and ar...

(al´kēn) an aliphatic hydrocarbon containing a double bond.

(al´kәl) the radical that results when an aliphatic hydrocarbon loses one hydrogen atom.

(al´kә-lāt) to cause the substitution of an alkyl group for an active hydrogen atom in an organic compound; see also alkylating agents.

alkylating agent
highly reactive, cytotoxic compounds that produce their effects by damaging a cell's DNA. Cell killing occurs primarily in rapidly proliferating tissues in which there is not time between mitoses for DNA repair systems to reverse the effects of the agent. Classes of antineoplastic alkylating agents include nitrogen mustar...

(al´kīn) an aliphatic hydrocarbon containing a triple bond.

acute lymphoblastic leukemia.

(al″ә-kes-the´zhә) allesthesia. optical allachesthesia visual allesthesia.

(al″an-ti´ә-sis) [allanto- + -iasis] a type of sausage poisoning from sausages containing the toxins of Clostridium botulinum. See botulism.

(ә-lan″to-kor´e-on) the allantois and chorion as one structure.

allantoic fluid
the fluid contained within the allantois.

allantoic sac
the dilated portion of the allantois, becoming a part of the placenta in many mammals; it becomes the urachus in humans.

allantoic veins
paired vessels that accompany the allantois; they enter the body stalk of the early embryo with the allantois and later form the umbilical veins.

allantoic vesicle
the internal hollow portion of the allantois.

(ә-lan´toid) sausage-shaped. pertaining to the allantois.

(ә-lan´to-in) a crystalline substance from allantoic fluid and fetal urine, also produced synthetically; used as an astringent and keratolytic, often as a component in multi-ingredient dermatological medications.

(ә-lan″to-in-u´re-ә) allantoin in the urine.

(ә-lan´to-is) a small sausage-shaped outpouching from the caudal wall of the yolk sac of the early embryo, associated with early blood formation and development of the urinary bladder; its blood vessels become the umbilical arteries and veins. adj., allanto´ic., adj.

(ә-lēl´) one of the two or more alternative forms of a gene that can occur at a particular chromosomal site (locus), and which determine alternative characters in inheritance. Because autosomal chromosomes occur in pairs, an individual will have two alleles, which may be the same or different, for each ...

(ә-le″lo-tak´sis) development of an organ from several embryonic structures.

Allemann syndrome
(ah´lә-mahn) the association of double kidney and clubbed fingers, sometimes associated with facial asymmetry and degeneration of various motor nerves.

Allen test
(al´әn) a test for occlusion of radial or ulnar arteries: the patient makes a tight fist so as to express the blood from the skin of the palm and fingers; the examiner makes digital compression on either the radial or ulnar artery. Failure of blood to return to the palm and fingers when the hand is opened in...

Allen-Doisy test
(a formerly common test for estrogens) the material being tested was injected into spayed laboratory mice and a change from leukocytes to cornified cells in their vaginal secretions was a positive result.

Allen's law
(al´әnz) whereas in normal individuals the more sugar is given the more is utilized, the reverse is true in diabetics.

(al´әr-jen) a substance, protein or nonprotein, capable of inducing allergy or specific hypersensitivity. a purified protein, most often of a food (such as milk, eggs, or wheat), a bacterium, or pollen, used to test a patient for hypersensitivity to specific substances (see skin test). Allergens may ...

(ә-lur´jik) pertaining to or having an allergy.

allergic asthma
asthma due to an allergy to antigens; usually the offending allergens are suspended in the air in the form of pollen, dust, smoke, automobile exhaust, animal dander, or similar substances. More than half of the cases of asthma in children and young adults are of this type. Called also extrinsic asthma.

allergic contact dermatitis
contact dermatitis due to allergic sensitization to various substances that produce inflammatory reactions in the skin of those who have acquired hypersensitivity to the allergen as a result of previous exposure to it.

allergic dermatitis
atopic dermatitis. allergic contact dermatitis.

allergic eczema
atopic dermatitis.

allergic reaction
a local or general reaction characterized by altered reactivity of the animal body to an antigenic substance; see also allergy.

allergic rhinitis
any allergic reaction of the nasal mucosa, occurring perennially (nonseasonal allergic rhinitis) or seasonally (hay fever).

(al´әr-jist) a physician specializing in the diagnosis and treatment of allergic conditions.

(al″әr-jĭ-za´shәn) active sensitization by introduction of allergens into the body.

(al´әr-je) a state of abnormal and individual hypersensitivity acquired through exposure to a particular substance called an allergen; reexposure reveals a heightened capacity to react. There are three major types of allergies: (1) delayed-reaction ones, caused by sensitized lymphocytes; (2) antigen-antibody react...

(al″es-the´zhә) the experiencing of a sensation (such as pain or touch) as occurring at a point remote from where the stimulus is actually applied. visual allesthesia the transposition of visual images from one-half of the visual field to the other. Called also optical allache...

(ә-le´ve-āt) to cause the lessening or disappearance of a patient's problem.

Allgrove syndrome
(awl´grōv) a recessively inherited disorder, consisting of abnormally low production of glucocorticoid hormones, failure of the smooth muscle fibers of the gastrointestinal tract to relax (achalasia), and inability to produce tears (alacrima). Called also achalasia-addisonian syndrome, addisonian-achalasia syndrome, and ...

allied health professional
a person with special training, certification, and licensing with responsibilities bearing on patient care. See also allied health.

allied reflexes
reflexes in which two afferent stimuli use the same common pathway or produce effects on two synergistic muscles.

alligator forceps
a grasping forceps with a scissorlike handle and blades opening in a vertical plane similar to the jaws of an alligator.

Allis sign
(al´is) relaxation of the fascia between the crest of the ilium and the greater trochanter; a sign of fracture of the neck of the femur.

(al″o-an´tĭ-bod″e) isoantibody.

(al″o-sen´trik) focused on the thoughts and feelings of others; not egocentric.

(al″o-ki´re-ә) allesthesia.

(al″o-din´e-ә) pain produced by a non-noxious stimulus.

(al″o-ә-rot´ĭ-siz-әm) sexual feeling directed to another person, as opposed to autoeroticism. a state of maturity characterized both by direction of erotic energies to another and also by the ability to form a love relationship with that other. adj., alloerot´ic., adj.

(al″o-jә-ne´ik) denoting individuals of the same species but of different genetic constitution (antigenically distinct); called also homologous.

allogeneic antigen
one found in some but not all individuals of the same species, such as the histocompatibility antigens and human blood group antigens; called also isoantigen.

allogeneic disease
graft-versus-host reaction occurring in immunosuppressed animals receiving injections of allogeneic lymphocytes.

allogeneic graft

allogeneic transplantation
transplantation of an allograft; the three types are cadaveric donor, living related donor, and living unrelated donor transplantation. Called also allotransplantation.

(al´o-graft) homologous graft. a graft of tissue between individuals of the same species but of disparate genotype; types of donors are cadaveric, living related, and living unrelated. Called also allogeneic graft and homograft.

alloimmune neonatal neutropenia
neutropenia in the newborn due to in utero incompatibility between its immunoglobulin G antigens and those of the mother's blood; the mother's blood produces antibodies that cross the placenta and sensitize fetal neutrophils. Affected infants may have fever, pneumonia, septicemia, and other infections that can be fatal. T...

(al´o-plas″te) in psychoanalytic theory, adaptation by alteration of the external environment (alloplastic change). adj., alloplas´tic., adj.

(al″o-pūr´ĭ-nol) a drug that inhibits uric acid production and reduces the amount of it in the serum and urine; used for treatment of hyperuricemia of gout and prevention and treatment of hyperuricemia secondary to blood dyscrasias or cancer chemotherapy and of uric acid nephropathy, as well as for prevention ...

(al″o-rith´me-ә) irregularity of the pulse.

(al″o-sta´sis) (ә-los´tә-sis) maintenance by an organism of internal physical or psychological stability by making changes during situations of challenge; see also allostatic load. adj., allostat´ic., adj.

(al″o-ster´ik) pertaining to an effect produced on the biological function of a protein by a compound not directly involved in that function (an allosteric effector) or to regulation of an enzyme involving cooperativity between multiple binding sites (allosteric sites).

allosteric site
a specific site on a multi-subunit enzyme that is not the substrate binding site but that when reversibly bound by an effector induces a shape change in the enzyme, altering its catalytic properties.

(al´o-thәrm″) an organism whose body temperature changes with its environment.

(al″o-trans-plan-ta´shәn) allogeneic transplantation.

(ә-lot″re-o-goo´ste-ә) abnormal sense of taste or appetite.

(al″o-tro´pik) exhibiting allotropism. more preoccupied with the ideas, actions, and feelings of others than with oneself.

(ә-lot´rә-piz″әm) existence of an element in two or more distinct forms, sometimes with different physical properties.

(ә-lot´rә-pe) allotropism.

(ә-lou´әns) something permitted or allowed. recommended daily allowance term popularly used as a synonym for recommended dietary allowance. recommended dietary allowance(RDA) the amount of nutrient and calorie intake per day co...

(ә-lok´san) an oxidized product of uric acid that tends to destroy the islet cells of the pancreas, thus producing diabetes mellitus. It has been obtained from intestinal mucus in diarrhea and has been used in nutrition experiments and as an antineoplastic agent.

alloxan diabetes
an animal model for diabetes mellitus; administration of alloxan produces selective destruction of the beta cells of the pancreas, causing hyperglycemia and ketoacidosis.

(al´oi) a solid mixture of two or more metals, or of one or more metals and certain metalloids, that are mutually soluble in the molten condition.

Almeida disease
(ahl-ma´dә) paracoccidioidomycosis.

almond oil
a preparation of the fixed oil obtained by expression from the seed of the almond (Prunus dulcis), used as an emollient, perfume, and oleaginousexcipient. bitter almond oil (def. 2).

(al″mo-trip´tan) a selective serotonin receptor agonist used as the malate salt in the acute treatment of migraine; administered orally.

(al´o) a succulent plant, of the genus Aloe. the dried juice of leaves of various species of Aloe, used in various dermatologic and cosmetic preparations.

(al″o-pe´shә) loss of hair. The cause of the simple condition is not yet fully understood, although it is known that the tendency is limited primarily to males, runs in certain families, and is more common in some racial groups than in others. It is often associated with aging, but can occur in younger perso...

alopecia areata
(al″o-pe´shә ar-e-a´tә) hair loss in sharply defined areas, usually the scalp or beard.

alopecia universalis
(al″o-pe´shә u″ĭ-vәr-sa´lis) loss of hair from the entire body.

Alouette amputation
Alouette operation amputation at the hip, with a semicircular outer flap to the great trochanter and a large internal flap from within outward; called also Alouette operation.

Alpers disease
(al´pәrz) poliodystrophia cerebri.

alpha angle
that formed by intersection of the visual axis with the optic axis.

alpha cell
a type of islet cell that secretes glucagon. acidophil (def. 2).

alpha chain disease
the most common heavy chain disease, occurring predominantly in young adults in the Mediterranean area, and characterized by plasma cell infiltration of the lamina propria of the small intestine resulting in malabsorption with diarrhea, abdominal pain, and weight loss, or, exceedingly rarely, by pulmonary involvement. The...

alpha coma
coma in which there are electroencephalographic findings of dominant alpha-wave activity.

alpha fibers
motor and proprioceptive fibers of the A type having conduction velocities of 70 to 120 meters per second and ranging from 13 to 22 micrometers in diameter.

alpha globulins
α-globulins serum globulins with the most rapid electrophoretic mobility, further subdivided into faster α1- and slower α2-globulins. See globulin.

alpha granules
oval granules found in blood platelets; they are lysosomes containing acid phosphatase. large granules in the alpha cells of the islets of Langerhans; they secrete glucagon. granules found in the acidophils of the adenohypophysis.

alpha lipoprotein
α-lipoprotein a lipoprotein belonging to a group having certain similar physical characteristics; the group essentially consists of the major high-density lipoproteins.

alpha rays
α-rays high-speed helium nuclei ejected from radioactive substances; they have less penetrating power than beta rays. See also alpha particles.

alpha receptors
α-receptors alpha-adrenergic receptors.

alpha rhythm
uniform rhythm of waves in the normal electroencephalogram; see alpha waves.