| ort-a-cath | A device surgically implanted under the skin, usually on the chest, that enters a large blood vessel and is used to deliver medication, chemotherapy, blood products and also is used to obtain blood samples. A port is usually inserted if a person has veins in the arm which are difficult to use for treatment or if certain types of chemotherapy drugs are to be given. (09 Oct 1997) |
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| ortalidian | <zoology> Any one of numerous small two-winged flies of the family Ortalidae. The larvae of many of these flies live in fruit; those of others produce galls on various plants. Source: Websters Dictionary (01 Mar 1998) |
| Orth's fixative | Formalin added to Muller's fixative, used for bringing out chromaffin, studying early degenerative processes and necrosis, and for demonstrating rickettsiae and bacteria. (05 Mar 2000) |
| Orth's stain | <technique> A lithium carmine stain for nerve cells and their processes. (05 Mar 2000) |
| Orth, Johannes | <person> German pathologist, 1847-1923. See: Orth's fixative, Orth's stain. (05 Mar 2000) |
| orthergasia | Rarely used term for normal intellectual and emotional adjustment. Origin: G. Orthos, straight, correct, + ergasia, work (05 Mar 2000) |
| orthesis | Rarely used term for an orthopedic brace, splint, or appliance. Origin: ortho-+ -esis, process (05 Mar 2000) |
| orthetics | The science concerned with the making and fitting of orthopaedic appliances. Synonym: orthetics. (05 Mar 2000) |
| orthid | <zoology> A brachiopod shell of the genus Orthis, and allied genera, of the family Orthidae. Source: Websters Dictionary (01 Mar 1998) |
| orthis | <zoology> An extinct genus of Brachiopoda, abundant in the Paleozoic rocks. Origin: NL, fr. Gr. Straight. Source: Websters Dictionary (01 Mar 1998) |
| orthite | <chemical> A variety of allanite occurring in slender prismatic crystals. Origin: Gr. Straight. Source: Websters Dictionary (01 Mar 1998) |
| ortho- | 1. <prefix> A combining form signifying straight, right, upright, correct, regular; as, orthodromy, orthodiagonal, orthodox, orthographic. 2. <chemistry> Connection with, or affinity to, one variety of isomerism, characteristic of the benzene compounds; contrasted with meta- or para-; as, the ortho position; hence, designating any substance showing such isomerism; as, an ortho compound. In the graphic representation of the benzene nucleus (see Benzene nucleus, under Benzene), provisionally adopted, any substance exhibiting double substitution in adjacent and contiguous carbon atoms, as 1 & 2, 3 & 4, 4 & 5, etc, is designated by ortho-; as, orthoxylene; any substance exhibiting substitution of two carbon atoms with one intervening, as 1 & 3, 2 & 4, 3 & 5, 4 & 6, etc, by meta-; as, resorcin or metaxylene; any substance exhibiting substitution in opposite parts, as 1 & 4, 2 & 5, 3 & 6, by para-; as, hydroquinone or paraxylene. Origin: Gr. Straight; akin to Skr. Rdhva upright, vrdh to grow, to cause to grow. (29 Oct 1998) |
| ortho-halobenzoate 1,2-dioxygenase | <enzyme> A three-component broad substrate-specific enzyme that requires oxygen, NADH, fe(ii) and flavin adenine dinucleotide; degrades 2,4-, 2,5-dichloro-, 2-chloro (& a variety of other substituted halobenzoates) to 4-chlorocatechol and catechol Registry number: EC 1.14.12.- (26 Jun 1999) |
| orthoacid | An acid in which the number of hydroxyl groups equals the valence of the acid-forming element; e.g., C(OH)4, orthocarbonic acid. When there is no such acid, the one that most nearly approaches this condition is sometimes called an orthoacid; e.g., OP(OH)3, orthophosphoric acid. (05 Mar 2000) |
| orthoarteriotony | Normal blood pressure. Origin: ortho-+ G. Arteria, artery, + tonos, tension (05 Mar 2000) |