Medical Dictionary

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barbital (bar′bi-tawl)
An obsolescent hypnotic and sedative; available as b. sodium (soluble b.), with the same uses; often used as a buffer. SYN: 5,5-diethylbarbituric acid, Veronal.

barbiturate (bar-bich′ur-at)
A derivative of barbituric acid, including phenobarbital and others, that act as CNS depressants and are used for their tranquilizing, hypnotic, and anti-seizure effects; most barbiturates have the potential for abuse.

barbituric acid (bar-bi-chur′ik)
A crystalline dibasic acid from which barbital and other barbiturates are derived; has no sedative action. SYN: malonylurea.

barbiturism (bar′bi-chur-izm)
Chronic poisoning by any of the derivatives of barbituric acid; symptoms, which are not very distinctive, include cutaneous eruption accompanied by chills, fever, and headache.

barbotage (bar-bo-tahzh′)
A method of spinal anesthesia in which a portion of the anesthetic solution is injected into the cerebrospinal fluid, which is then aspirated back into the syringe and reinjected. [Fr. barboter, to dabble]

barbula hirci (bar′bu-la hir′si)
The hairs growing from the tragus, antitragus, and incisura intertragica of the auricle of men after age 27 years. [L. dim. of barba, beard, + gen. sing. of hircus, goat]

Barclay
Alfred E., English physician, 1877–1949. See B.-Baron disease.

Barcroft
Sir Joseph F., English physiologist, 1872–1947. See B.-Warburg apparatus, B.-Warburg technique.

Bard
Philip, U.S. physiologist, 1898–1945. See Cannon-B. theory.

Bardet
Georges, French physician, *1885. See B.-Biedl syndrome.

Bardinet
Barthélemy A., French physician, 1809–1874. See B. ligament.

baresthesia (bar-es-the′ze-a)
SYN: pressure sense. [G. baros, weight, + aisthesis, sensation]

baresthesiometer (bar′es-the′ze-om′e-ter)
An instrument for measuring the pressure sense. [G. baros, weight, + aisthesis, sensation, + metron, measure]

bariatric (bar-e-at′rik)
Relating to bariatrics.

bariatrics (bar-e-at′riks)
That branch of medicine concerned with the management (prevention or control) of obesity and allied diseases. [G. baros, weight, + iatreia, medical treatment]

baric (ba′rik)
Relating to barometric pressure (as in isobar) or to weight generally.

baricity (ba-ris′i-te)
The weight of one substance compared to the weight of an equal volume of another substance at the same temperature. [G. baros, weight]

barilla (ba-ril′a)
Commercial, usually impure, sodium carbonate and sulfate.

baritosis (bar-i-to′sis)
A form of pneumoconiosis caused by barite or barium dust.

barium (Ba) (ba′re-um, ba′re-um)
A metallic, alkaline, divalent earth element; atomic no. 56, atomic wt. 137.327. Insoluble salts are often used in radiology as contrast media. [G. barys, heavy] b. chloride formerly used as a heart tonic and for varicose veins; extremely toxic. b. hydroxide a caustic compound combined with calcium hydroxide in a carbon dioxide absorbent; used in anesthetic circuits. SEE ALSO: absorbent (3) . b. meal oral administration of b. sulfate suspension for radiographic study of the upper gastrointestinal tract (British usage). b. oxide, b. monoxide it is caustic, forming the strong base, Ba(OH)2, in water; used as a dehydrating agent. SYN: baryta. b. sulfate given as a suspension orally, rectally, or through a tube, for radiographic demonstration of a part of the gastrointestinal tract. See enteroclysis, b. enema. b. sulfide a poisonous grayish yellow powder, used as a depilatory. b. swallow oral administration of b. sulfate suspension for radiographic investigation of the hypopharynx and esophagus.

bark
1. The envelope or covering of the roots, trunk, and branches of plants. Barks of pharmacological significance not listed below are alphabetized under specific names. 2. SYN: cinchona. cinchona b. SYN: cinchona. cotton-root b. dried root b. of Gossypium herbaceum and other species of Gossypium (family Malvaceae). Has been used as an abortifacient and oxytocic.

Barkan
Otto, U.S. ophthalmologist, 1887–1958. See B. membrane, B. operation.

Barkman
Åke, 20th century Swedish internist. See B. reflex.

Barkow
Hans K.L., German anatomist, 1798–1873. See B. ligaments, under ligament.

Barlow
John B., South African cardiologist, *1924. See B. syndrome.

Barlow
Sir Thomas, British physician, 1845–1945. See B. disease.

barn (b)
A unit of area for effective cross-section of atomic nuclei with respect to atomic projectiles; equal to 10−24 cm2. [fr. “big as the side of a b.” by humorous comparison with much smaller areas]

Barnard
Christiaan, South African surgeon, *1922, performed the first successful heart transplant in 1967.

Barnes
Robert, British obstetrician, 1817–1907. See B. curve, B. zone.

Barnes
Stanley, British physician, 1875–1955.

baro-
Weight, pressure. [G. baros, weight]

baroceptor (bar′o-sep-ter, -tor)
SYN: baroreceptor.

barognosis (bar′og-no′sis)
Ability to appreciate the weight of objects, or to differentiate objects of different weights. [G. baros, weight, + gnosis, knowledge]

barograph (bar′o-graf)
A device that gives a continuous record of barometric pressure. SYN: barometrograph.

barometrograph (bar-o-met′ro-graf)
SYN: barograph.

Baron
See Barclay-B. disease.

barophilic (bar′o-fil′ik)
Thriving under high environmental pressure; applied to microorganisms. [G. baros, weight, + phileo, to love]

baroreceptor (bar′o-re-sep′ter, -tor)
1. In general, any sensor of pressure changes. 2. Sensory nerve ending in the wall of the auricles of the heart, vena cava, aortic arch, and carotid sinus, sensitive to stretching of the wall resulting from increased pressure from within, and functioning as the receptor of central reflex mechanisms that tend to reduce that pressure. SYN: baroceptor, pressoreceptor. [G. baros, weight, + receptor]

baroreflex (bar-o-re′fleks)
A reflex triggered by stimulation of a baroreceptor.

baroscope (bar′o-skop)
An instrument measuring changes in atmospheric pressure.

barosinusitis (bar′o-si-nus-i′tis)
Inflammation of the mucous membrane of the paranasal sinuses caused by pressure difference within the sinus relative to ambient pressure, secondary to obstruction of the sinus ostium and occurring during descent in altitude. SYN: aerosinusitis. [G. baros, weight, pressure, + sinusitis]

barostat (bar′o-stat)
A pressure-regulating device or structure, such as the baroreceptors of the carotid sinus and aortic arch, when connected to effectors providing negative feedback. [G., baros, weight, pressure, + statos, made to stand]

barotaxis (bar-o-tak′sis)
Reaction of living tissue to changes in pressure. SYN: barotropism. [G. baros, weight, + taxis, order]

barotitis media (bar-o-ti′tis me′de-a)
Inflammation of the mucous membrane of the middle ear caused by pressure difference within the middle ear relative to ambient pressure, secondary to obstruction of the auditory tube or its failure to open; often occurs on descent in altitude. SYN: aerotitis media.

barotrauma (bar′o-traw′ma)
A term previously used to describe injury to the middle ear or paranasal sinuses, resulting from imbalance between ambient pressure and that within the affected cavity. Now mostly used to refer to lung injury due to pressure such as occurs when a patient is on a ventilator and is subjected to high airway pressure (pulmonary b.). [G. baros, weight, + trauma] otic b. injury caused to the ear by imbalance in pressure between ambient air and the air in the middle ear. SEE ALSO: barotitis media. sinus b. injury to paranasal sinuses, resulting from imbalance in pressure between ambient air and air in the paranasal sinuses. SEE ALSO: barosinusitis.

barotropism (bar-ot′ro-pizm)
SYN: barotaxis. [G. baros, weight, + trope, a turning]

Barr
Yvonne M., English virologist, *1932. See Epstein-B. virus.

Barr
Murray L., Canadian microanatomist, *1908. See B. chromatin body.

Barraquer
Ignacio, Spanish ophthalmologist, 1884–1965. See B. method.

Barraquer Roviralta
Luis, Spanish physician, 1855–1928. See Barraquer disease.

Barré
Jean A., French neurologist, *1880. See Barré sign, Guillain-Barré reflex, Guillain-Barré syndrome, Landry-Guillain-Barré syndrome.

barren (bar′en)
Unable to produce a pregnancy. [M.E. bareyne]

Barrett
Norman R., British physician, *1903. See adenocarcinoma in B. esophagus, B. esophagus, B. epithelium, B. syndrome, B. metaplasia.

barrier (bar′e-er)
1. An obstacle or impediment. 2. In psychiatry, a conflictual agent that blocks behavior that could help resolve a personal struggle. [M.E., fr. O.Fr. barriere, fr. L.L. barraria] blood-air b. the material intervening between alveolar air and the blood; it consists of a nonstructural film or surfactant, alveolar epithelium, basement lamina, and endothelium. blood-aqueous b. a selectively permeable b. between the capillary bed in the processes of the ciliary body and the aqueous humor in the anterior chamber of the eye; consists of two layers of simple cuboidal epithelium joined at their apical surfaces with junctional complexes. blood-brain b. (BBB) a selective mechanism opposing the passage of most ions and large–molecular weight compounds from the blood to brain tissue located in a continuous layer of endothelial cells connected by tight junctions; similar capillaries are found in the retina, iris, inner ear, and within the endoneurium of peripheral nerves. blood-cerebrospinal fluid b., blood-CSF b. a b. located at the tight junctions which surround and connect the cuboidal epithelial cells on the surface of the choroid plexus; capillaries and connective tissue stroma of the choroid do not represent a b. to protein tracers or dyes. blood-testis b. an occluding b. formed by Sertoli cells in the seminiferous tubules of the testis, which separates the more mature cells of spermatogenesis in the adlumenal compartment of the tubule from blood-derived products in the basal compartment. blood-thymus b. a sheath of pericytes and epithelial reticular cells around thymic capillaries that prevents the developing T lymphocytes of the thymus from being exposed to circulating antigens. incest b. in psychoanalysis, the learning or internalization of parental and social prohibitions against incest. placental b. SYN: placental membrane.

Bart
Bruce J., U.S. dermatologist, *1936. See B. syndrome.

Bartels
Peter H., German scientist in U.S., specializing in optics and computer science, *1929.

Barth
Jean B.P., Strasburg physician, 1806–1877. See B. hernia.

Bartholin
Casper, Danish anatomist, 1655–1738. See B. abscess, B. cyst, B. cystectomy, B. duct, B. gland.

Bartholin
Thomas, Danish anatomist, 1616–1680. See B. anus.

bartholinitis (bar-to-lin-i′tis)
Inflammation of a vulvovaginal (Bartholin) gland.

Bartley
Samuel H., U.S. psychologist, *1901. See Brücke-B. phenomenon.

Barton
John Rhea, U.S. surgeon, 1794–1871. See B. bandage, B. forceps, B. fracture.

Bartonella (bar-to-nel′a)
A genus of bacteria found in humans and in arthropod vectors; grows slowly in artificial media and may be recovered from blood cultures from infected patients; may be seen intracellularly in tissues and erythrocytes. B. is a minute, Gram-negative, coccobacillary organism, which may appear curved; it can cause an indolent, poorly defined, progressive disease in immunocompromised patients, including those with HIV infections. [A. L. Barton] B. bacilliformis a species found in the blood and epithelial cells of lymph nodes, spleen, and liver in Oroya fever (it is the cause of Oroya fever) and in blood and eruptive elements in verruga peruana; probably also found in sandflies (Phlebotomus verrucarum); known to be established only on the South American continent and perhaps in Central America; it is the type species of the genus B.. B. henselae a bacterial species that causes catscratch disease in persons with normal immunity and bacillary angiomatosis in persons with AIDS. SEE ALSO: catscratch disease. B. quintana formerly the type species of the genus Rochalimaea, this organism causes trench fever and in AIDS patients is associated with septicemia and endocarditis; arthropod vector is Pediculus humanus, the body louse.

Bartonellaceae (bar-ton-el-a′se-e)
A family of bacteria that currently includes the genus Bartonella. Based upon S16 rRNA studies, the former genera of Rochalimaea and Grahamella have been merged with the genus Bartonella, retaining their species names.

bartonellosis (bar-to-nel-o′sis)
A disease caused by infection with a species of bacteria belonging to the genus Bartonella,

Bart's
Nickname of St. Bartholomew's Hospital in London, where hemoglobin Bart was first isolated from a patient.

Bartter
Frederic C., U.S. physician, 1914–1983. See B. syndrome.

Baruch
Simon, U.S. physician, 1840–1921. See B. law.

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