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| Medical Dictionary - Dictionary of Medicine and Human Biology |
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Medical Dictionary
ζ, upper case Ζ
the left-handed uncommon form of double helix DNA in which the chains twist up and to the left around the front of the axis of the helix and which has 12 base pairs in each helical turn and one groove on the external surface z distribution a probability density function and especially a normal distribution that has a mean equal to zero and a standard deviation equal to one and that is used especially in testing hypotheses about means or proportions of samples drawn from populations whose population standard deviations are known Z line any of the dark thin bands across a striated muscle fiber that mark the junction of actin filaments in adjacent sarcomeres Z particle a neutral elementary particle about 90 times heavier than a proton that along with the W particle is a transmitter of the weak force, also called Z0, or Z0 particle Zaffaroni Alejandro, Uruguayan-U.S. chemist and biochemist, *1923. See Z. system. zafirlukast (za-fir-loo′kast) A blocker of leukotriene D4 and E4 (LTD4 and LTE4) components of a slow-reacting substance of anaphylaxis (SRSA); used for the prophylaxis of asthma attacks. Zaglas John, 19th century anatomist's assistant in Edinburgh. See Z. ligament. Zahn Friedrich W., German pathologist, 1845–1904. See Z. infarct, lines of Z., under line, striae of Z., under stria. Zambusch Leo von, 20th century German physician. See generalized pustular psoriasis of Z.. zanamivir (zan-am′i-vir) An agent that inhibits neuraminidase of influenza virus. Zappert Julius, Austrian physician, 1867–1942. See Z. counting chamber. Zavanelli William, 20th century U.S. obstetrician. See Z. maneuver. zea (ze′a) The styles and stigmas of Z. mays (family Gramineae), Indian corn; formerly used as a diuretic and antispasmodic. SYN: cornsilk. [Mod. L. maize] zearalenone (ze′a-ral-en-on) One of the resorcylic acid lactones; used in veterinary medicine as an anabolic. zeatin (ze′a-tin) A cytokinin first isolated from kernels of sweet corn. SYN: maize factor. zeaxanthin (ze′a-zan′thin) A carotene found in corn, fruits, seeds, and egg yolk; isomeric with xanthophyll. SYN: zeaxanthol. [Mod. L. Zea, Indian corn, fr. L. zea, grain + G. xanthos, yellow, + -in] zeaxanthol (ze-a-za-thol) SYN: zeaxanthin. Zeeman Pieter, Dutch physicist and Nobel laureate, 1865–1943. See Z. effect. ZEEP Abbreviation for zero end-expiratory pressure. zein (ze′in) A prolamine present in maize; it lacks chiefly the amino acids l-tryptophan and l-lysine and is also low in cysteine content. It is the main storage protein in maize. Zeis Eduard, Dresden ophthalmologist, 1807–1868. See Z. glands, under gland, zeisian sty. zeisian (zis′e-an) Relating to or described by Eduard Zeis. Zeitgeist (zit′gist) In psychology, the climate of opinion, conventions of thought, covert influences, and unquestioned assumptions that are implicit in a given culture, the arts, or science at any point in time, and in which the individual operates and thus is influenced. [Ger. zeit, time, + geist, spirit] Zellweger Hans U., U.S. pediatrician, 1909–1990. See Z. syndrome. zelophobia (ze-lo-fo′be-a) Morbid fear of jealousy. [G. zelos, zeal, + phobos, fear] zelotypia (ze-lo-tip′e-a) Excessive zeal, carried to the point of morbidity, in the advocacy of any cause. [G. z.; rivalry, envy, fr. zelos, zeal, + typto, to strike] Zenker Friedrich A., German pathologist, 1825–1898. See Z. degeneration, Z. diverticulum, Z. fixative, Z. paralysis, formol-Z. fixative. zeolite (ze′o-lit) A naturally occurring hydrated sodium aluminum silicate, Na2O&chmpnt;Al2O3&chmpnt;(SiO2)x&chmpnt;(H2O)x, used for softening of hard water by exchanging its Na+ for the Ca2+ of the water; thus z. is an ion exchanger. Some synthetic ion exchangers are termed synthetic zeolites, although there is no chemical relationship. zeoscope (ze′o-skop) A device for determining the alcoholic content of a liquid by ascertaining its exact boiling point. [G. zeo, to boil, + skopeo, to examine] zepto- (z) Prefix used in the SI and metric systems to signify submultiples of 10−21. zero (ze′ro) 1. The figure 0, indicating the absence of magnitude, or nothing. 2. In thermometry, the point from which the figures on the scale start in one or the other direction; in the Celsius and Réaumur scales, z. indicates the freezing point for distilled water; in the Fahrenheit scale, it is 32° below the freezing point of water. [Sp. fr. Ar. sifr, cipher] absolute z. the lowest possible temperature, that at which the form of translational motion constituting heat is assumed no longer to exist, determined as −273.15°C or 0 kelvin. zero gravity (ze-ro-grav′i-te) A physical state existing in space or at a time in flight when the centrifugal thrust of a parabolic glide or turn exactly counteracts the force of gravity. zetacrit (za′ta-krit) The packed cell volume produced by vertical centrifugation of blood in capillary tubes, allowing controlled compaction and dispersion of red blood cells; read with a hematocrit to produce the zeta sedimentation ratio. zetaprotein SYN: fibronectins. zeugmatography (zoog-ma-tog′ra-fe) Term coined by Lauterbur in 1972 for the joining of a magnetic field and spatially defined radiofrequency field gradients to generate a two-dimensional display of proton density and relaxation times in tissues, the first nuclear magnetic resonance image. [G. zeugma, that which joins together] zidovudine (zi-do′voo-den) A thymidine analog that is an inhibitor of in vitro replication of HIV virus, the causative agent of AIDS and ARC, and is used in the management of these diseases. SYN: azidothymidine. Ziegler Samuel L., U.S. ophthalmologist, 1861–1926. Ziehen Georg T., German psychiatrist, 1862–1950. See Z.-Oppenheim disease. Ziehl Franz, German bacteriologist, 1857–1926. See Z. stain, Z.-Neelsen stain. Ziemann Hans R.P., German pathologist, 1865–1939. See Z. dots, under dot, Z. stippling. Zieve Leslie, U.S. physician, *1915. See Z. syndrome. Zimmerlin Franz, Swiss physician, 1858–1932. See Z. atrophy. Zimmermann Karl W., German histologist, 1861–1935. See Z. corpuscle, Z. granule, Z. elementary particle, polkissen of Z.. Zimmermann Wilhelm, German physician, *1910. See Z. reaction, Z. test. zinc (Zn) (zingk)
A radioactive zinc isotope that decays mainly by K-capture with a half-life of 243.8 days; used as a tracer in studies of zinc metabolism. zinciferous (zing-kif′er-us) Containing zinc. zincoid (zing′koyd) Relating to or resembling zinc. [G. eidos, resemblance] zingiber (zin′ji-ber) SYN: ginger. Zinn Johann G., German anatomist, 1727–1759. See Z. artery, Z. vascular circle, Z. corona, Z. ligament, Z. membrane, Z. ring, Z. tendon, Z. zonule. Zinsser Hans, U.S. bacteriologist and immunologist, 1878–1940. See Brill-Z. disease. zirconium (Zr) (zir-ko′ne-um) A metallic element, atomic no. 40, atomic wt. 91.224; widely distributed in nature, but never found in quantity in any one place. [zircon, a mineral, fr. Ar. zarkun, cinnabar, Pers, zargun, goldlike] zirconium oxide Used as a coating for the skin in dermatologic pharmaceuticals and as a pigment in paints. zm Abbreviation for zeptometer. Zn Symbol for zinc. 65Zn Abbreviation for zinc-65. Zo2 Symbol for microliters of oxygen taken up per hour by 108 spermatozoa; can vary as a function of temperature. zo- See zoo-. zoanthropic (zo-an-throp′ik) Relating to or marked by zoanthropy. zoanthropy (zo-an′thro-pe) A delusion that one is an animal, such as a dog. [G. zoon, animal, + anthropos, man] zoetic (zo-et′ik) Relating to life. [G. zoe, life] zoic (zo′ik) Relating to living things; having life. [G. zoikos, relating to an animal] zoite (zo′it) SYN: sporozoite. [G. zoon, animal] Zollinger Robert M., U.S. surgeon, *1903. See Z.-Ellison syndrome, Z.-Ellison tumor. Zöllner Johann F., German physicist, 1834–1882. See Z. lines, under line. zolpidem (zol′pe-dem) A sedative/hypnotic drug useful for treating anxiety and resembling benzodiazepines in its pharmacology but differing somewhat in chemical structure. Unlike benzodiazepines, z. lacks prominent anticonvulsant properties, and less tolerance may develop with its use. zomepirac sodium (zo-me-pir′ak) An analgesic anti-inflammatory agent, no longer marketed. zona, pl .zonae (zo′na, zo′ne)
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, Photius Coutsoukis and Information Technology Associates (All rights reserved).
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