| antirachitic vitamins | Ergocalciferol (v. D2) and cholecalciferol (v. D3). (05 Mar 2000) |
|---|---|
| vitamins | For the various vitamins see Vitamins. The word vitamin was coined in 1911 by the warsaw-born biochemist casimir funk (1884-1967). at the lister institute in london, funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance vitamine because he believed it was necessary to life and it was a chemical amine. The e at the end was later removed when it was recognised that vitamins need not be amines. The letters (a, b, c and so on) were assigned to the vitamins in the order of their discovery. The one exception was vitamin k which was assigned its k from koagulation by the danish researcher henrik dam. (12 Dec 1998) |
| fat-soluble vitamins | Those vitamin's, soluble in fat solvents (nonpolar solvents) and relatively insoluble in water, marked in chemical structure by the presence of large hydrocarbon moieties in the molecule; e.g., vitamin's A, D, E, K. (05 Mar 2000) |
| prenatal | <obstetrics> Existing or occurring before birth, with reference to the foetus. Origin: L. Natalis = natal (18 Nov 1997) |
| prenatal care | Care provided the pregnant woman in order to prevent complications, and decrease the incidence of maternal and prenatal mortality. (12 Dec 1998) |
| prenatal diagnosis | Determination of the nature of a pathological condition or disease in the postimplantation embryo, foetus, or pregnant female before birth. (12 Dec 1998) |
| prenatal exposure delayed effects | Delayed effects on offspring of maternal or foetal prenatal exposure to drugs, radiation and other physical agents, manipulation, nutrition, stress, etc. (12 Dec 1998) |
| prenatal life | That interval of life between conception and birth; in humans, usually divided into embryonic and foetal periods. (05 Mar 2000) |
| prenatal screening | Screening for the detection of foetal disease, usually by ultrasound examination or by testing amniotic fluid obtained by amniocentesis. Other screening techniques include testing maternal serum and placental biopsy. (05 Mar 2000) |
| ultrasonography, prenatal | The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the foetus and with reference to organs or the detection of maternal or foetal disease. (12 Dec 1998) |
| bimolecular step | <chemistry> Two species are reacting and form the transition state (09 Jan 1998) |
| rate-limiting step | <biochemistry> The slowest step in a metabolic pathway, or the step in an enzymatic reaction that requires the greatest amount of energy to initiate. (17 Dec 1997) |
| Master's two-step exercise test | An early and long-used exercise challenge to identify ischemic heart disease using a pair of nine inch steps with a platform on top, the number of trips by the patient arbitrarily chosen and related to age and body weight. See: two-step exercise test. Synonym: Master's two-step exercise test. (05 Mar 2000) |
| Gomori's one-step trichrome stain | <technique> A connective tissue stain that uses haematoxylin and a dye mixture containing chromotrope 2R and light green or aniline blue; muscle fibres appear red, collagen is green (or blue if aniline blue is used), and nuclei are blue to black. (05 Mar 2000) |
| Ronne's nasal step | A nasal visual field defect with one margin corresponding to the retinal horizontal medium; seen in glaucoma. (05 Mar 2000) |