Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

ascorbate
(ә-skor´bāt) a compound or derivative of ascorbic acid.

ascorbic acid
(ә-skor´bik) vitamin C.

ASCP
American Society of Clinical Pathologists.

Ascriptin
(ә-skrip´tin) trademark for a preparation of aspirin with Maalox (magnesium oxide and aluminum hydroxide), an analgesic, antipyretic, and antiinflammatory, and an inhibitor of platelet aggregation.

ASCT
autologous stem cell transplantation.

ascus
(as´kәs) the spore case of certain fungi.

ASD
atrial septal defect.

asemasia
(as″ә-ma´zhә) asymbolia.

Asendin
(ә-sen´din) trademark for a preparation of amoxapine, a tricyclic antidepressant.

asepsis
(a-sep´sis) freedom from infection or infectious material. the absence of viable pathogenic organisms; see also aseptic technique. adj., asep´tic., adj.

aseptic
(a-sep´tik) free from infection; called also sterile.

aseptic fever
fever associated with aseptic wounds, presumably due to the disintegration of leukocytes or to the absorption of avascular or traumatized tissue.

aseptic meningitis
any of several mild types of meningitis, most of which are caused by viruses.

aseptic necrosis
necrosis without infection or inflammation.

aseptic technique
the use of surgical practices that restrict microorganisms in the environment and prevent contamination of the surgical wound (see surgical asepsis). Called also sterile technique.

asexual
(a-sek´shoo-әl) without sex; not pertaining to or involving sex.

asexual generation
production of a new organism not originating from union of gametes.

asexual reproduction
reproduction without the fusion of germ cells.

ASGE
American Society for Gastrointestinal Endoscopy.

ASH
American Society of Hematology.

Asherman syndrome
(ash´әr-mәn) persistent amenorrhea and secondary sterility due to intrauterine adhesions and synechiae, usually as a result of uterine curettage.

Asherson syndrome
(ash´әr-sәn) a syndrome of dysphagia due to neuromuscular incoordination and achalasia of the cricopharyngeus muscle during the third stage of swallowing. It causes diversion of liquids into the air passages, precipitating paroxysms of coughing. Called also cricopharyngeal achalasia syndrome.

Ashman phenomenon
(ash´mәn) a condition seen in atrial fibrillation, in which a long cardiac cycle (R–R interval) is immediately followed by a short cycle with the next beat conducted aberrantly.

ASIA
American Spinal Injury Association.

ASIA scale
a descriptive tool developed by the American Spinal Injury Association (ASIA) as a part of the complete classification of patients with spinal cord injuries. Called also Frankel Classification.

asialia
(a″si-a´le-ә) aptyalism.

asiderosis
(a″sid-әr-o´sis) deficiency of iron reserve of the body.

Ask-Upmark kidney
a kidney with fewer lobules than usual and fissures on its surface; most affected persons have severe hypertension, sometimes with hypertensive encephalopathy and retinopathy. The condition may be either congenital or secondary to ve

Askin tumor
a type of malignant small-cell tumor of soft tissue found in the chest region of children; it is a type of peripheral neuroectodermal tumor.

asparaginase
(as-par´ә-jin-ās″) an enzyme that catalyzes removal of the amine group that results in breakdown of asparagine; used as an antineoplastic agent against cancers such as acute lymphoblastic leukemia in which the malignant cells require exogenous asparagine for protein synthesis.

asparagine
(ә-spar´ә-jēn) (ә-spar´ә-jin) the β-amide of aspartic acid, a nonessential amino acid that is also used as a culture medium for certain bacteria.

aspartame
(ә-spahr´tām) (as´pahr-tām″) a synthetic compound of two amino acids, used as a low-calorie sweetener. It is 180 times as sweet as sucrose (table sugar). Aspartame does not promote the formation of dental caries. The amount of phenylalanine it contains must be taken into account in the l...

aspartate
(ә-spahr´tāt) any salt of aspartic acid; aspartic acid in dissociated form.

aspartate transaminase
(AST) (ASAT) (ә-spahr´tāt trans-am´ĭ-nās) an enzyme that catalyzes the reversible transfer of an amino group from aspartate to α-ketoglutarate to form glutamate and oxaloacetate, requiring the coenzyme pyridoxal phosphate; it is normally present in serum and...

aspartic acid
(ә-spahr´tik) a nonessential amino acid that is widely distributed in proteins and found as an excitatory neurotransmitter in the central nervous system.

aspect
(as´pekt) that part of a surface viewed from a particular direction. the look or appearance. anterior aspect that surface of the body or a body part viewed from the front; in humans this is a synonym of ventral aspect. dorsal aspect see poster...

Asperger syndrome
(ahs´pәr-gәr) a pervasive developmental disorder resembling autistic disorder, characterized by severe impairment of social interactions and restricted interests and behaviors, but lacking the delays in development of language, cognitive function, and self-help skills that additionally define autistic disord...

aspergilloma
(as″pәr-jil-o´mә) the most common kind of fungus ball formed by colonization of Aspergillus in a bronchus or lung cavity.

aspergillosis
(as″pәr-jil-o´sis) a disease caused by species of Aspergillus, marked by inflammatory granulomatous lesions in the skin, ear, orbit, nasal sinuses, lungs, and sometimes bones and meninges. bronchopulmonary aspergillosis infection of the lungs and bronchi by Aspergillus; see as...

Aspergillus
(as″pәr-jil´әs) a genus of fungi (molds), several species of which are endoparasitic and opportunistic pathogens.

Aspergillus
pneumonia a type of fungal pneumonia sometimes seen in pulmonary aspergillosis.

aspermatogenesis
(a-spur″mә-to-jen´ә-sis) failure in a male of production of spermatozoa.

aspermia
(ә-spur´me-ә) aspermatogenesis. anejaculation.

asphyxia
(as-fik´se-ә) pathological changes caused by lack of oxygen in respired air, resulting in a deficiency of oxygen in the blood (hypoxia) and an increase in carbon dioxide in the blood and tissues (hypercapnia). Symptoms include irregular and disturbed respirations, or a complete absence of breathing, and pallor or cyanos...

asphyxiant
(as-fik´se-әnt) any substance capable of producing asphyxia.

asphyxiate
(as-fik´se-āt) to suffocate; to deprive of oxygen for utilization by the tissues.

asphyxiation
(as-fik″se-a´shәn) suffocation.

aspidium
(as-pid´e-әm) the dried products of a genus of plants known as male fern; it was formerly used to treat tapeworm infestations but was found to be highly toxic to the gastrointestinal tract.

aspirate
(as´pĭ-rāt) to withdraw fluid by negative pressure, or suction; see aspiration (def. 3). the fluid withdrawn this way.

aspirating needle
a long, hollow needle for removing fluid from a cavity.

aspiration
(as″pĭ-ra´shәn) inhalation of some foreign material; aspiration of vomitus, blood, or mucus may occur when a person is unconscious or under the effects of a general anesthetic, and can be avoided by keeping the head turned to the side and removing all such foreign material from the air passages.&n...

aspiration biopsy
one in which tissue is obtained by application of suction through a needle attached to a syringe.

aspiration pneumonia
pneumonia due to the entrance of foreign matter, such as food particles, into the respiratory passages or lungs.

aspirator
(as″pĭ-ra´tәr) an instrument for evacuating fluid by suction; see aspiration (def. 3).

aspirin
(as´pĭ-rin) acetylsalicylic acid, a common nonsteroidal antiinflammatory drug used to relieve pain and reduce fever, and specifically prescribed for rheumatic and arthritic disorders. See salicylate for adverse reactions and poisoning. Aspirin should not be given to children who have viral infections, because this has ...

aspirin tolerance test
any of various bleeding time tests in which aspirin is administered and its effect on bleeding time is assessed; aspirin prolongs bleeding time in patients with von Willebrand disease and certain other platelet disorders.

asplenia
(a-sple´ne-ә) absence of the spleen.

asplenia syndrome
Ivemark syndrome.

asporogenic
(as″po-ro-jen´ik) not producing spores; not reproduced by spores.

asporous
(ә-spor´әs) having no true spores.

ASRT
American Society of Radiologic Technologists.

assay
(as´a) determination of the purity of a substance or the amount of any particular constituent of a mixture.

assertiveness
(ә-sur´tiv-nes) a form of behavior characterized by a confident declaration or affirmation of a statement without need of proof; this affirms the person's rights or point of view without either aggressively threatening the rights of another (assuming a position of dominance) or submissively permitting anothe...

assertiveness training
instruction and practice in techniques for dealing with interpersonal conflicts and threatening situations with the use of assertiveness, avoiding extremes of aggressive and submissive behavior. The goal is to enable the learner to express personal feelings freely, speak up for his or her rights, communicate disagreement ...

assident sign
accessory sign.

assignment
(ә-sīn´mәnt) the selection of something for a specific purpose.

assimilation
(ә-sim″ĭ-la´shәn) psychologically, absorption of new experiences into the existing personality. Called also integration. anabolism. the process by which members of a culture change their lifeways in order to become totally integrated into another culture.

assimilation pelvis
one in which the ilia articulate with the vertebral column higher (high assimilation pelvis) or lower (low assimilation pelvis) than normal, the number of lumbar vertebrae being correspondingly decreased or increased.

assist mode
a mode of positive pressure ventilation in which the patient initiates and terminates all or most breaths and the ventilator gives some amount of support. See also control mode and assist-control mode.

assist mode ventilation
positive pressure ventilation in which the ventilator is in the assist-control mode; see also control mode ventilation and assist/control mode ventilation.

assist-control mode
a mode of positive pressure ventilation in which the ventilator is in assist mode unless the patient's respiration rate falls below a certain amount, in which case the ventilator switches to a control mode. When the strength or rate of respiration increases again, the ventilator goes back into assist mode.

assist-control mode ventilation
positive pressure ventilation in the assist-control mode; if the spontaneous ventilation rate falls below a preset level, the ventilator enters the control mode.

assistant
(ә-sis´tәnt) one who aids or helps another; an auxiliary. first assistant a physician, physician assistant, nurse practitioner, surgical technologist, or specially trained registered professional nurse who directly assists the surgeon by handling tissue, providing exp...

assisted mode
assist mode.

assisted reproduction
assisted fertility.

assisted ventilation
artificial respiration.

associated movement
movement of parts that act together, as the eyes.

association
(ә-so″se-a´shәn) a state in which two attributes occur together either more or less often than expected by chance. in neurology, a term applied to those regions of the brain (association areas) that link the primary motor and sensory areas. in genetics, the occurrence together of ...

association areas
areas of the cerebral cortex (excluding primary areas) connected with each other and with the neothalamus; they are responsible for higher mental and emotional processes, including memory, learning, speech, and the interpretation of sensations.

association fibers
nerve fibers that interconnect portions of the cerebral cortex within a hemisphere. Short association fibers interconnect neighboring gyri; long fibers interconnect more widely separated gyri and are arranged into bundles or fasciculi.

association system
the cortex and related tracts of fibers in the brain by means of which perceptions are associated and thought rendered possible.

association test
one based on associative reaction, usually by mentioning words to a person and noting what other words they give as the ones called to mind; see association (def. 4).

associative reaction
a reaction in which the response is withheld until the idea presented has suggested an associated idea.

assortative
(ә-sor´tә-tiv) characterized by or pertaining to selection on the basis of likeness or kind.

assortive
(ә-sor´tiv) assortative.

assortment
(ә-sort´mәnt) the random distribution of different combinations of the parental chromosomes to the gametes, each gamete thus containing one chromosome of each homologous pair, but randomly receiving the maternal versus paternal homologue for any pair. independent assortment ...

AST
Association of Surgical Technologists; aspartate transaminase.

astasia
(as-ta´zhә) motor incoordination with inability to stand. adj., astat´ic., adj. astasia-abasia motor incoordination with an inability to stand or walk despite normal ability to move the legs when sitting or lying down, a form of hysterical ataxia.

astatine
(At) (as´tә-tēn) a chemical element, atomic number 85, atomic weight 210.

asteatosis
(as″te-ә-to´sis) any disease in which persistent dry scaling of the skin suggests scantiness or absence of sebum.

aster
(as´tәr) a structure occurring in dividing cells, composed of microtubules radiating from each pair of centrioles. The two asters are the poles of the spindle apparatus. Asters separating in prophase of mitosis.

astereognosis
(ә-ster″e-og-no´sis) loss or lack of the ability to understand the form and nature of objects that are touched (stereognosis), a form of tactile agnosia.

asterion
(as-te´re-on) the point on the surface of the skull where the lambdoid, parietomastoid, and occipitomastoid sutures meet. Asterion.

asterixis
(as″tәr-ik´sis) a motor disturbance marked by intermittent lapses of an assumed posture because sustained contraction of groups of muscles lapses; sometimes called “liver flap” because of its occurrence in coma associated with liver disease, although it is also observed in other conditions.

asternal
(a-stur´nәl) not joined to the sternum. pertaining to asternia.

asternal ribs
false ribs.

asternia
(a-stur´ne-ә) congenital absence of the sternum.

asteroid
(as´tәr-oid) star-shaped.

asteroid body
an irregularly star-shaped inclusion body found in the giant cells in sarcoidosis and other diseases.

asthenia
(as-the´ne-ә) weakness; loss of strength and energy; called also adynamia and debility. adj., asthen´ic., adj. neurocirculatory asthenia Da Costa syndrome.