| HeLa | <cell culture, oncology> Referring to cells of the first continuously cultured (human cervical) carcinoma strain. An established line of human epithelial cells derived from a cervical caracinoma (from a black American woman called Henrietta Lacks). In fact the cellular biomass now considerably exceeds that of Henrietta herself ! These cells are used for virus cultivation and antitumour drug screening assays. Origin: Henrietta Lacks (d. 1951). (21 Jun 2000) |
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| helamys | <zoology> See Jumping hare, under Hare. Origin: NL, fr. Gr. Fawn + mouse. Source: Websters Dictionary (01 Mar 1998) |
| Helbings' sign | <clinical sign> A malalignment of the Achilles tendon associated with a valgus deformity of the os calcis. (05 Mar 2000) |
| helcomenia | Occurrence of ulcers at the time of a menstruation. Origin: G. Helkos, ulcer, + emmenos, monthly (05 Mar 2000) |
| helcoplasty | <medicine> The act or process of repairing lesions made by ulcers, especially by a plastic operation. Origin: Gr. A wound + -plasty. Source: Websters Dictionary (01 Mar 1998) |
| Held | Hans, German anatomist, 1866-1942. See: Held's bundle, Held's decussation. (05 Mar 2000) |
| Held's bundle | A bundle of thick, heavily myelinated fibres originating in the deep layers of the superior colliculus, crossing to the opposite side in the dorsal tegmental decussation, descending along the median plane, between the medial longitudinal fasciculus dorsally, the medial lemniscus ventrally, into the anterior funiculus of the spinal cord. The tract ends in the medial region of the anterior horn of the cervical spinal cord, and appears to be involved in head movements during visual and auditory tracking. Throughout its course in the brainstem it is accompanied by fibres of the tectobulbar tract. Synonym: tractus tectospinalis, Held's bundle, Loewenthal's bundle, Loewenthal's tract, Marchi's tract, predorsal bundle. (05 Mar 2000) |
| Held's decussation | The crossing of some of the fibres arising from the cochlear nuclei to form the lateral lemniscus. (05 Mar 2000) |
| helenin | <chemistry> A neutral organic substance found in the root of the elecampane (Inula helenium), and extracted as a white crystalline or oily material, with a slightly bitter taste. Source: Websters Dictionary (01 Mar 1998) |
| heliacal | <astronomy> Emerging from the light of the sun, or passing into it; rising or setting at the same, or nearly the same, time as the sun. The heliacal rising of a star is when, after being in conjunction with the sun, and invisible, it emerges from the light so as to be visible in the morning before sunrising. On the contrary, the heliacal setting of a star is when the sun approaches conjunction so near as to render the star invisible. Origin: Gr. Belonging to the sun, fr. The sun: cf. F. Heliaque. Source: Websters Dictionary (01 Mar 1998) |
| helianthin | <chemistry> An artificial, orange dyestuff, analogous to tropaolin, and like it used as an indicator in alkalimetry. Synonym: methyl orange. Origin: Prob. Fr. L. Helianthes, or NL. Helianthus, sunflower, in allusion to its colour. Source: Websters Dictionary (01 Mar 1998) |
| helianthine | C14H14N3O3SNa;a weakly acid dye used as a pH indicator (red at 3.2, yellow at 4.4). Synonym: helianthine. (05 Mar 2000) |
| helianthoid | <zoology> Of or pertaining to the Helianthoidea. Source: Websters Dictionary (01 Mar 1998) |
| helianthoidea | <zoology> An order of Anthozoa; the Actinaria. Origin: NL, fr. L. Helianthes sunflower. Source: Websters Dictionary (01 Mar 1998) |
| helianthus | A genus of tall, erect american herbs of the compositae. The seeds yield oil and are used as food and animal feed; the roots of helianthus tuberosum (jerusalem artichoke) are edible. (12 Dec 1998) |