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stichochrome (stik′o-krom)
Denoting a nerve cell in which the chromophil substance, or stainable material, is arranged in roughly parallel rows or lines. [G. stichos, a row, + chroma, color]

Stickler
Gunnar B., U.S. physician, *1925. See S. syndrome.

Stieda
Ludwig, German anatomist, 1837–1918. See S. process.

Stieda
Alfred, German surgeon, 1869–1945. See Pellegrini-S. disease.

Stierlin
Eduard, German surgeon, 1878–1919. See S. sign.

stigma, pl .stigmasstigmata (stig′ma, -ma-ta)
1. Visible evidence of a disease. 2. SYN: follicular s.. 3. Any spot or blemish on the skin. 4. A bleeding spot on the skin, which is considered a manifestation of conversion hysteria. 5. The orange-pigmented eyespot of certain chlorophyll-bearing protozoa, such as Euglena viridis, which serves as a light filter by absorbing certain wavelengths. 6. A mark of shame or discredit. [G. a mark. fr. stizo, to prick] follicular s. the point where the graafian follicle is about to rupture on the surface of the ovary. SYN: macula pellucida, s. (2) . malpighian stigmas the points of entrance of the smaller veins into the larger veins of the spleen. s. ventriculi one of a number of miliary ecchymoses of the gastric mucosa.

stigmastane (stig-mas′tan)
The parent substance of sitosterol. SYN: sitostane.

stigmata (stig′ma-ta)
Alternative plural of stigma.

stigmatic (stig-mat′ik)
Relating to or marked by a stigma.

stigmatism (stig′ma-tizm)
The condition of having a stigma. SYN: stigmatization (1) .

stigmatization (stig′ma-ti-za′shun)
1. SYN: stigmatism. 2. Production of stigmas, especially of a hysterical nature. 3. Debasement of a person by attributing a negatively toned characteristic or other stigma to him or her.

stilbamidine (stil-bam′i-den)
A compound used in the treatment of leishmaniasis (kala azar), in infections due to Blastomyces dermatitidis, and in actinomycosis; also used in multiple myeloma for the relief of bone pain.

stilbazium iodide (stil-baz′e-um)
An anthelmintic.

stilbene (stil′ben)
1. C6H5CH&dbond;CHC6H5; α,β-diphenylethylene;an unsaturated hydrocarbon, the nucleus of stilbestrol and other synthetic estrogenic compounds. 2. A class of compounds based on s. (1).

stilbestrol (stil-bes′trol)
SYN: diethylstilbestrol.

Stiles
Walter S., English physicist, 1901–1985. See S.-Crawford effect.

stilet, stilette (sti′let, sti-let′)
See stylet.

Still
Sir George F., English physician, 1868–1941. See S. disease, S. murmur, S.-Chauffard syndrome.

stillbirth (stil′berth)
The birth of an infant who has died prior to delivery.

stillborn (stil′born)
Born dead; denoting an infant dead at birth.

Stilling
Benedict, German anatomist, 1810–1879. See S. canal, S. column, S. nucleus, S. raphe, S. gelatinous substance.

stilus (sti′lus)
See stylus.

stimulant (stim′u-lant)
1. Stimulating; exciting to action. 2. An agent that arouses organic activity, strengthens the action of the heart, increases vitality, and promotes a sense of well-being; classified according to the parts upon which they chiefly act: cardiac, respiratory, gastric, hepatic, cerebral, spinal, vascular, genital. SYN: excitor, stimulator. SEE ALSO: stimulus. SYN: excitant. [L. stimulans, pres. p. of stimulo, pp. -atus, to goad, incite, fr. stimulus, a goad] diffusible s. a s. that produces a rapid but temporary effect. general s. a s. that affects the entire body. local s. a s. whose action is confined to the part to which it is applied.

stimulation (stim-u-la′shun)
1. Arousal of the body or any of its parts or organs to increased functional activity. 2. The condition of being stimulated. 3. In neurophysiology, the application of a stimulus to a responsive structure, such as a nerve or muscle, regardless of whether the strength of the stimulus is sufficient to produce excitation. [see stimulant] dorsal column s. electrical s., either percutaneously or by direct application of electrodes to the dorsal columns of the spinal cord. fetal scalp s. intrapartum test for fetal well-being; acceleration of the fetal heart rate in response to digital or forceps s. of scalp is associated with a normal scalp blood pH. Ganzfeld s. illumination of the entire retina in the electroretinogram. [Ger. Ganzfeld, whole field] percutaneous s. electrical s. of the peripheral nerves or spinal cord by the application of electrodes to the skin. photic s. the use of a flickering light at various frequencies to influence the pattern of the occipital electroencephalogram and also to activate latent abnormalities. vagal nerve s. an adjunctive treatment for patients with intractable epilepsy, particularly complex partial or secondarily generalized seizures; s. is delivered to the left vagus nerve in the neck, usually in 30-s bursts every 512 min by a stimulator implanted in the anterior chest wall.

stimulator (stim′u-la-ter, -tor)
SYN: stimulant (2) . long-acting thyroid s. (LATS) a substance, found in the blood of some hyperthyroid patients, that exerts a prolonged stimulatory effect on the thyroid gland; associated in plasma with the IgG (7 S γ-globulin) fraction and seems to be an antibody or, perhaps, an immune complex.

stimulus, pl .stimuli (stim′u-lus, -li)
1. A stimulant. 2. That which can elicit or evoke action (response) in a muscle, nerve, gland or other excitable tissue, or cause an augmenting action upon any function or metabolic process. [L. a goad] adequate s. a s. to which a particular receptor responds effectively and that gives rise to a characteristic sensation; e.g., light and sound waves that stimulate, respectively, visual and auditory receptors. aversive s. a noxious s. such as an electric shock used in aversive training or conditioning. SEE ALSO: aversive training. conditioned s. 1. a s. applied to one of the sense organs ( e.g., receptors of vision, hearing, touch) which are an essential and integral part of the neural mechanism underlying a conditioned reflex; See classical conditioning, higher order conditioning. 2. a neutral s., when paired with the unconditioned s. in simultaneous presentation to an organism, capable of eliciting a given response. discriminant s. a s. which can be differentiated from all other stimuli in the environment because it has been, and continues to serve as, an indicator of a potential reinforcer. heterologous s. a s. that acts upon any part of the sensory apparatus or nerve tract. heterotopic s. any electrical activation from an abnormal locus. homologous s. a s. that acts only on the nerve terminations in a special sense organ. inadequate s. SYN: subthreshold s.. liminal s. SYN: threshold s.. maximal s. a s. strong enough to evoke a maximal response. square wave stimuli electrical stimulation in which the intensity of the current is brought suddenly to a given level and maintained at that level until it suddenly is cut off; this type of s. is particularly useful in obtaining a strength-duration curve. subliminal s. SYN: subthreshold s.. subthreshold s. a s. too weak to evoke a response. SYN: inadequate s., subliminal s.. supramaximal s. a s. having strength significantly above that required to activate all of the nerve or muscle fibers in contact with the electrode; used when response of all the fibers is desired. threshold s. a s. of threshold strength, i.e., one just strong enough to excite. SEE ALSO: adequate s.. SYN: liminal s.. train-of-four s. a method for measuring magnitude and type of neuromuscular blockade, based upon the ratio of the amplitude of the fourth evoked mechanical response to the first one, when four supramaximal 2-Hz electrical currents are applied for 2 s to a peripheral motor nerve. unconditioned s. a s. that elicits an unconditioned response; e.g., food is an unconditioned s. for salivation, which in turn is an unconditioned response in a hungry animal. See classical conditioning.

stimulus word
The word used in association tests to evoke a response.

sting
1. Sharp momentary pain, most commonly produced by the puncture of the skin by many species of arthropods, including hexapods, myriapods, and arachnids; can also be produced by jellyfish, sea urchins, sponges, mollusks, and several species of venomous fish, such as the stingray, toadfish, rabbitfish, and catfish. 2. The venom apparatus of a stinging animal, consisting of a chitinous spicule or bony spine and a venom gland or sac. 3. To introduce (or the process of introducing) a venom by stinging. [O.E. stingan]

stingers (sting′erz)
SYN: burners.

stink weed
SYN: Datura stramonium.

stippling (stip′ling)
1. A speckling of a blood cell or other structure with fine dots when exposed to the action of a basic stain, due to the presence of free basophil granules in the cell protoplasm. SYN: punctate basophilia. 2. An orange peel appearance of the attached gingiva. 3. A roughening of the surfaces of a denture base to stimulate natural gingival s.. geographic s. of nails regularly arranged longitudinal s. found commonly in psoriasis and occasionally in alopecia areata. SEE ALSO: nail pits, under pit. Ziemann s. SYN: Ziemann dots, under dot.

STIR
Acronym for short TI inversion recovery.

Stirling
William, British histologist and physiologist, 1851–1932. See S. modification of Gram stain.

stirrup (ster′up, stir′up)
SYN: stapes. [A.S. stirap]

stitch
1. A sharp sticking pain of momentary duration. 2. A single suture. 3. SYN: suture (2) . [A.S. stice, a pricking] lock s. SYN: locking suture.

STM
Abbreviation for short-term memory.

Stock
Wolfgang, German ophthalmologist, 1874–1956. See Spielmeyer-S. disease.

stock (stok)
All the populations of organisms derived from an isolate without any implication of homogeneity or characterization. [A.S. stoc]

Stocker
Frederick William, U.S. ophthalmologist, 1893–1974. See S. line.

Stoffel
Adolf, German orthopedic surgeon, 1880–1937. See S. operation.

stoichiology (stoy-ke-ol′-o-je)
The science concerned with the elements or principles in any branch of knowledge, especially in chemistry, cytology, or histology. [G. stoicheion, element (lit. one of a row), fr. stoichos, a row, + logos, study]

stoichiometric (stoy′ke-o-met′rik)
Pertaining to stoichiometry.

stoichiometry (stoy-ke-om′e-tre)
Determination of the relative quantities of the substances concerned in any chemical reaction; e.g., with the laws of definite proportions in chemistry, as in the molar proportions in a reaction. [G. stoicheion, element, + metron, measure]

stoke (stok)
A unit of kinematic viscosity, that of a fluid with a viscosity of 1 poise and a density of 1 g/ml; equal to 10−4 m2/s. [Sir George Gabriel Stokes]

Stokes
Sir George Gabriel, British physicist and mathematician, 1819–1903. See stoke, S. law (2) , S. law (3) .

Stokes
William, Irish physician, 1804–1878. See S. law (1) , Cheyne-S. psychosis, Cheyne-S. respiration, S.-Adams disease, Adams-S. disease, Morgagni-Adams-S. syndrome.

Stokes
Sir William, Irish surgeon, 1839–1900. See S. amputation, Gritti-S. amputation.

stolon (sto′lon)
A runner or connective aerial hypha that forms a cluster of rhizoids when it touches the substrate, and then sends out other runners to produce the aerial mycelium and sporangiosphores typical of Rhizopus. [L. stolo, branch, shoot, twig]

stom-
See stomato-.

stoma, pl .stomasstomata (sto′ma, sto′maz, sto′ma-ta)
1. A minute opening or pore. 2. An artificial opening between two cavities or canals, or between such and the surface of the body. [G. a mouth] Fuchs stomas small depression on the surface of the iris near the margin of the pupil. loop s. a specialized s. of intestine or ureter by which a loop of the hollow viscus is brought through an opening in the abdominal wall, with an opening created in the apex of the viscus to allow egress of its contents.

stomach (stum′uk) [TA]
A large irregularly piriform sac between the esophagus and the small intestine, lying just beneath the diaphragm; when distended it is 25–28 cm in length and 10–10.5 cm in its greatest diameter, and has a capacity of about 1 L. Its wall has four coats or tunics: mucous, submucous, muscular, and peritoneal; the muscular coat is composed of three layers, the fibers running longitudinally in the outer, circularly in the middle, and obliquely in the inner layer. SYN: gaster (1) [TA] , ventriculus (1) [TA] . [G. stomachos, L. stomachus] bilocular s. SYN: hourglass s.. s. bubble the gas in the fundus of the s. seen on an upright radiograph. cascade s. a radiographic description: when contrast material is swallowed while the patient is in the upright position, the gastric fundus acts as a reservoir until contrast overflows (cascades) into the antrum; a normal variant in a horizontal s.. drain-trap s. SYN: water-trap s.. hourglass s. a condition in which there is a central constriction of the wall of the s. dividing it into two cavities, cardiac and pyloric. SYN: bilocular s., ectasia ventriculi paradoxa. leather-bottle s. marked thickening and rigidity of the s. wall, with reduced capacity of the lumen although often without obstruction; nearly always due to scirrhous carcinoma, as in linitis plastica. SYN: sclerotic s.. miniature s. SYN: Pavlov pouch. Pavlov s. SYN: Pavlov pouch. powdered s. the dried and powdered defatted wall of the s. of the hog, Sus scrofa; it contains thermolabile factors including native vitamin B12 and intrinsic factor; has been used in the treatment of pernicious anemia. sclerotic s. SYN: leather-bottle s.. thoracic s. a condition in which part or all of the s. is contained within the thorax because of a paraesophageal hiatus hernia. trifid s. a condition in which the s. is divided by two constrictions into three pouches. wallet s. a form of dilated s. in which there is a general baglike distention, the antrum and fundus being indistinguishable. water-trap s. a ptotic and dilated s., having a relatively high (though normally placed) pyloric outlet which is held up by the gastrohepatic ligament. SYN: drain-trap s..

stomachal (stum′a-kal)
Relating to the stomach. SYN: stomachic (1) .

stomachalgia (stum-a-kal′je-a)
Obsolete term for stomach ache. [stomach + G. algos, pain]

stomachic (sto′mak′ik)
1. SYN: stomachal. 2. An agent that improves appetite and digestion.

stomachodynia (stum′a-ko-din′e-a)
Obsolete term for stomach ache. [stomach + G. odyne, pain]

stomal (sto′mal)
Relating to a stoma.

stomat-
See stomato-.

stomata (sto′ma-ta)
Alternate plural of stoma.

stomatal (sto′ma-tal)
Relating to a stoma.

stomatalgia (sto-ma-tal′je-a)
Pain in the mouth. SYN: stomatodynia. [stomat- + G. algos, pain]

stomatic (sto-mat′ik)
Relating to the mouth; oral.

stomatitis (sto-ma-ti′tis)
Inflammation of the mucous membrane of the mouth. [stomat- + G. -itis, inflammation] angular s. SYN: angular cheilitis. aphthous s. SYN: aphtha (2) . epidemic s. contagious mouth infection, usually due to Group A coxsackievirus. SEE ALSO: herpangina. fusospirochetal s. infection of the mouth with spirochetal organisms, usually in association with other anaerobes. SEE ALSO: Vincent angina. gangrenous s. s. characterized by necrosis of oral tissue. See noma. gonococcal s. inflammatory and ulcerative oral lesions resulting from infection with Neisseria gonorrhoeae; usually primary as a result of oral-genital contact, but occasionally is the result of gonococcemia. lead s. oral manifestation of lead poisoning consisting of a bluish-black line following the contours of the marginal gingiva where lead sulfide has precipitated due to the inflamed environment. s. medicamentosa inflammatory alterations of the oral mucosa associated with a systemic drug allergy; lesions may consist of erythema, vesicles, bullae, ulcerations, or angioneurotic edema. mercurial s. alterations of the oral mucosa arising from chronic mercury poisoning; may consist of mucosal erythema and edema, ulceration, and deposition of mercurial sulfide in inflamed tissues, resulting in oral pigmentation resembling that of lead s.. nicotine s. heat-stimulated lesions, usually on the palate, that begin with erythema and progress to multiple white papules with a red dot in the center. The red dot represents a dilated, inflamed salivary duct orifice. primary herpetic s. first infection of oral tissues with herpes simplex virus; characterized by gingival inflammation, vesicles, and ulcers. SYN: primary herpetic gingivostomatitis. recurrent aphthous s. SYN: aphtha (2) . recurrent herpetic s. reactivation of herpes simplex virus infection, characterized by vesicles and ulceration limited to the hard palate and attached gingiva. recurrent ulcerative s. SYN: aphtha (2) . ulcerative s. SYN: aphtha (2) . vesicular s. a vesicular disease of horses, cattle, swine, and occasionally humans caused by a Vesiculovirus (vesicular s. virus) in the family Rhabdoviridae; in horses and cattle the disease usually causes mouth vesicles which, in cattle, cannot be differentiated clinically from those of foot-and-mouth disease.

stomato-, stom-, stomat-
Mouth. [G. stoma]

stomatocyte (sto′ma-to-sit)
A red blood cell that exhibits a slit or mouth-shaped pallor rather than a central one on air-dried smears; e.g., Rh null cells. [stomato- + G. kytos, cell]




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