| indirect lead | One of the three original bipolar limb lead's of the clinical electrocardiogram, designated I, II and III: lead I records the potential difference between the right and left arms; lead II the difference between right arm and left leg; and lead III the difference between left arm and left leg. Synonym: indirect lead. (05 Mar 2000) |
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| internal carotid (nervous) plexus | An autonomic plexus surrounding the internal carotid artery in the carotid canal and cavernous sinus, and sending branches to the tympanic plexus, sphenopalatine ganglion, abducens and oculomotor nerves, the cerebral vessels, and the ciliary ganglion. Synonym: internal carotid venous plexus. (05 Mar 2000) |
| intracardiac lead | The record obtained when the exploring electrode is placed within one of the heart's chambers, usually by means of cardiac catheterization. (05 Mar 2000) |
| oesophageal lead | An electrocardiographic lead passed down the throat into the oesophagus to record the electrocardiogram at various levels of the oesophagus; especially useful for certain types of arrhythmias. Similarly, a transducer for echocardiography can be passed into the oesophagus. (05 Mar 2000) |
| tetraethyl lead | Pb(C2H5)4; tetraethylplumbane;an anti-knock compound added to motor fuel; has a toxic action causing anorexia, nausea, vomiting, diarrhoea, tremors, muscular weakness, insomnia, irritability, nervousness, and anxiety; death may occur. Synonym: lead tetraethyl. (05 Mar 2000) Previous: tetraethylammonium, tetraethylammonium chloride, tetraethylammonium ionNext: tetraethyl lead, tetraethylmonothionopyrophosphatetetraethyl lead <chemical> Tetraethylplumbane. A highly toxic compound used as a gasoline additive. It causes acute toxic psychosis or chronic poisoning if inhaled or absorbed through the skin. Chemical name: Plumbane, tetraethyl- (12 Dec 1998) |
| ECG lead | An electrocardiographic cable with connections within the electronics of the machine designated for an electrode placed at a particular point on the body surface. (05 Mar 2000) |
| lead | 1. To guide or conduct with the hand, or by means of some physical contact connection; as, a father leads a child; a jockey leads a horse with a halter; a dog leads a blind man. "If a blind man lead a blind man, both fall down in the ditch." (Wyclif (Matt. Xv. 14)) "They thrust him out of the city, and led him unto the brow of the hill." (Luke iv. 29) "In thy right hand lead with thee The mountain nymph, sweet Liberty." (Milton) 2. To guide or conduct in a certain course, or to a certain place or end, by making the way known; to show the way, especially. By going with or going in advance of. Hence, figuratively: To direct; to counsel; to instruct; as, to lead a traveler; to lead a pupil. "The Lord went before them by day in a pillar of a cloud, to lead them the way." (Ex. Xiii. 21) "He leadeth me beside the still waters." (Ps. Xxiii. 2) "This thought might lead me through the world's vain mask. Content, though blind, had I no better guide." (Milton) 3. To conduct or direct with authority; to have direction or charge of; as, to lead an army, an exploring party, or a search; to lead a political party. "Christ took not upon him flesh and blood that he might conquer and rule nations, lead armies, or possess places." (South) 4. To go or to be in advance of; to precede; hence, to be foremost or chief among; as, the big sloop led the fleet of yachts; the Guards led the attack; Demosthenes leads the orators of all ages. "As Hesperus, that leads the sun his way." (Fairfax) "And lo ! Ben Adhem's name led all the rest." (Leigh Hunt) 5. To draw or direct by influence, whether good or bad; to prevail on; to induce; to entice; to allure; as, to lead one to espouse a righteous cause. "He was driven by the necessities of the times, more than led by his own disposition, to any rigor of actions." (Eikon Basilike) "Silly women, laden with sins,led away by divers lusts." (2 Tim. Iii. 6 (Rev. Ver)) 6. To guide or conduct one's self in, through, or along (a certain course); hence, to proceed in the way of; to follow the path or course of; to pass; to spend. Also, to cause (one) to proceed or follow in (a certain course). "That we may lead a quiet and peaceable life." (1 Tim. Ii. 2) "Nor thou with shadowed hint confuse A life that leads melodious days." (Tennyson) "You remember . . . The life he used to lead his wife and daughter." (Dickens) 7. To begin a game, round, or trick, with; as, to lead trumps; the double five was led. To lead astray, to guide in a wrong way, or into error; to seduce from truth or rectitude. To lead captive, to carry or bring into captivity. To lead the way, to show the way by going in front; to act as guide. Origin: OE. Leden, AS. Ldan (akin to OS. Ldian, D. Leiden, G. Leiten,Icel. Lea, Sw. Leda, Dan.lede), properly a causative fr. AS. Lian to go; akin to OHG. La, Icel. La,Goth. Leipan (in comp). Cf. Lode, Loath. 1. <chemistry> One of the elements, a heavy, pliable, inelastic metal, having a bright, bluish colour, but easily tarnished. It is both malleable and ductile, though with little tenacity, and is used for tubes, sheets, bullets, etc. Its specific gravity is 11.37. It is easily fusible, forms alloys with other metals, and is an ingredient of solder and type metal. Atomic weight.4. Symbol Pb (L. Plumbum). It is chiefly obtained from the mineral galena, lead sulphide. 2. An article made of lead or an alloy of lead; as: A plummet or mass of lead, used in sounding at sea. A thin strip of type metal, used to separate lines of type in printing. Sheets or plates of lead used as a covering for roofs; hence, pl, a roof covered with lead sheets or terne plates. "I would have the tower two stories, and goodly leads upon the top." (Bacon) 3. A small cylinder of black lead or plumbago, used in pencils. Black lead, graphite or plumbago,; so called from its leadlike appearance and streak. Coasting lead, a sounding lead intermediate in weight between a hand lead and deep-sea lead. Deep-sea lead, the heaviest of sounding leads, used in water exceeding a hundred fathoms in depth. Hand lead, a small lead use for sounding in shallow water. Krems lead, Kremnitz lead [so called from Krems or Kremnitz, in Austria], a pure variety of white lead, formed into tablets, and called also Krems, or Kremnitz, white, and Vienna white. Lead arming, tallow put in the hollow of a sounding lead. See To arm the lead (below). Lead colic. See Colic. Lead colour, a deep bluish gray colour, like tarnished lead. Lead glance. <medicine> A massive sulphur-yellow oxide of lead. Same as Massicot. Lead pencil, a pencil of which the marking material is graphite (black lead). <botany> Lead plant, crocoite. Sugar of lead, acetate of lead. To arm the lead, to fill the hollow in the bottom of a sounding lead with tallow in order to discover the nature of the bottom by the substances adhering. To cast, or heave, the lead, to cast the sounding lead for ascertaining the depth of water. White lead, hydrated carbonate of lead, obtained as a white, amorphous powder, and much used as an ingredient of white paint. Origin: OE. Led, leed, lead, AS. Lead; akin to D. Lood, MHG. Lot, G. Loth plummet, sounding lead, small weight, Sw. & Dan. Lod. 1. The act of leading or conducting; guidance; direction; as, to take the lead; to be under the lead of another. "At the time I speak of, and having a momentary lead, . . . I am sure I did my country important service." (Burke) 2. Precedence; advance position; also, the measure of precedence; as, the white horse had the lead; a lead of a boat's length, or of half a second. 3. The act or right of playing first in a game or round; the card suit, or piece, so played; as, your partner has the lead. 4. An open way in an ice field. 5. <chemical> A lode. 6. The course of a rope from end to end. 7. <engineering> The width of port opening which is uncovered by the valve, for the admission or release of steam, at the instant when the piston is at end of its stroke. When used alone it means outside lead, or lead for the admission of steam. Inside lead refers to the release or exhaust. 8. <engineering> The distance of haul, as from a cutting to an embankment. 9. The action of a tooth, as a tooth of a wheel, in impelling another tooth or a pallet. Lead angle, the main longitudinal screw of a lathe, which gives the feed motion to the carriage. Source: Websters Dictionary (01 Mar 1998) |
| lead acetate | Has been used as an astringent in diarrhoea, and in aqueous solution as a wet dressing in certain dermatoses. Synonym: sugar of lead. (05 Mar 2000) |
| lead anaemia | Anaemia associated with poisoning from lead; thought to result from a defect in synthesis of haemoglobin based on the failure of iron being combined in the porphyrin ring. (05 Mar 2000) |
| lead carbonate | A heavy white powder that is insoluble in water; occasionally, it is used to relieve irritation in dermatitis, but it is used largely in the manufacture of paint and in the arts and is thus productive of lead poisoning. Synonym: ceruse, white lead. (05 Mar 2000) |
| lead chromate | A fine yellow powder used in paints and dyes. Synonym: lead chromate, Leipzig yellow, lemon yellow, Paris yellow. (05 Mar 2000) |
| lead colic | Severe colicky abdominal pain, with constipation, symptomatic of lead poisoning. Synonym: Devonshire colic, painter's colic, Poitou colic, saturnine colic. (05 Mar 2000) |
| lead encephalitis | A metabolic encephalopathy, caused by the ingestion of lead compounds and seen particularly in early childhood; it is characterised pathologically by extensive cerebral oedema, status spongiosus, neurocytolysis, and some reactive inflammation; clinical manifestations include convulsions, delirium, and hallucinations. See: lead poisoning. Synonym: lead encephalitis, saturnine encephalopathy. (05 Mar 2000) |
| lead encephalopathy | A metabolic encephalopathy, caused by the ingestion of lead compounds and seen particularly in early childhood; it is characterised pathologically by extensive cerebral oedema, status spongiosus, neurocytolysis, and some reactive inflammation; clinical manifestations include convulsions, delirium, and hallucinations. See: lead poisoning. Synonym: lead encephalitis, saturnine encephalopathy. (05 Mar 2000) |
| lead gout | saturnine gout |