| pineal tumours | <radiology> SIGNS: aqueductal obstruction most likely to be hydrocephalus, paralysis of upward gaze (due to pressure on quarigeminal plate), precocious puberty, symptoms of hypothalamic, thalamic, cerebellar or pyramidal lesion TYPES: germ-cell (teratoid) tumours, teratoma, germinoma / atypical teratoma, endodermal sinus (yolk sac) tumour, choriocarcinoma, pineal-cell tumours, pineocytoma, pineo---, others, glioma, ganglioneuroma, ganglioglioma (12 Dec 1998) |
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| pinealectomy | Removal of the pineal body. Origin: pineal + G. Ektome, excision (05 Mar 2000) |
| pinealocyte | A cell of the pineal body with long processes ending in bulbous expansions. Pinealocytes receive a direct innervation from sympathetic neurons that form recognizable synapses. The club-shaped endings of pinealocyte processes terminate in perivascular spaces surrounding capillaries. Synonym: chief cell of corpus pineale, parenchymatous cell of corpus pineale. Origin: pineal + G. Kytos, cell (05 Mar 2000) |
| pinealoma | A tumour of the pineal body composed of neoplastic nests of large cells. Tumours in this region are rare, accounting for less than 1% of intracranial tumours, although in children they constitute 3%-8% of intracranial tumours. Its symptoms include hydrocephalus, conjugate paralysis of upward gaze, disturbances of gait, and precocious puberty, the last due to suppression of pineal secretion of melatonin. Because pinealomas are near the centre of the brain, they are among the most difficult of brain tumours to remove. A variety of surgical approaches has been described. Radiotherapy and chemotherapy are also used. (12 Dec 1998) |
| pinealopathy | Disease of the pineal gland. Origin: pineal + G. Pathos, disease (05 Mar 2000) |
| pineapple | <botany> A tropical plant (Ananassa sativa); also, its fruit; so called from the resemblance of the latter, in shape and external appearance, to the cone of the pine tree. Its origin is unknown, though conjectured to be American. Source: Websters Dictionary (01 Mar 1998) |
| pinedrops | <botany> A reddish herb (Pterospora andromedea) of the United States, found parasitic on the roots of pine trees. Source: Websters Dictionary (01 Mar 1998) |
| pinefinch | <zoology> A small American bird (Spinus, or Chrysomitris, spinus). Synonym: pine siskin, and American siskin. The pine grosbeak. Source: Websters Dictionary (01 Mar 1998) |
| Pinel's system | The abolition of forcible restraint in the treatment of the mental hospital patient. (05 Mar 2000) |
| Pinel, Philippe | <person> French psychiatrist, 1745-1826. See: Pinel's system. (05 Mar 2000) |
| pinenchyma | <botany> Tabular parenchyma, a form of cellular tissue in which the cells are broad and flat, as in some kinds of epidermis. Origin: NL, fr. Gr. A tablet + -enchyma, as in parenchyma. Source: Websters Dictionary (01 Mar 1998) |
| pineoblastoma | A type of brain tumour. (12 Dec 1998) |
| pineocytoma | A type of brain tumour. (12 Dec 1998) |
| pinesap | <botany> A reddish fleshy herb of the genus Monotropa (M. Hypopitys), formerly thought to be parasitic on the roots of pine trees, but more probably saprophytic. Source: Websters Dictionary (01 Mar 1998) |
| pinetum | A plantation of pine trees; especially, a collection of living pine trees made for ornamental or scientific purposes. Origin: L, a pine grove. Source: Websters Dictionary (01 Mar 1998) |