| hydrocephalus | A condition marked by dilatation of the cerebral ventricles, most often occurring secondarily to obstruction of the cerebrospinal fluid pathways and accompanied by an accumulation of cerebrospinal fluid within the skull, the fluid is usually under increased pressure, but occasionally may be normal or nearly so. It is typically characterised by enlargement of the head, prominence of the forehead, brain atrophy, mental deterioration and convulsions, may be congenital or acquired and may be of sudden onset (acute h.) or be slowly progressive (chronic or primary b.). Origin: Gr. Kephal = head (18 Nov 1997) |
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| hydrocephalus ex vacuo | Hydrocephalus due to loss or atrophy of brain tissue; less commonly associated with raised intracranial pressure. (05 Mar 2000) |
| hydrocephaly | An increased quantity of cerebrospinal fluid (CSF) inside the brain that can result in increased pressure. Often the result of a disturbance (obstruction) in the normal CSF circulation or the over-production of CSF. (27 Sep 1997) |
| hydrochlorate | <chemistry> Same as Hydrochloride. Source: Websters Dictionary (01 Mar 1998) |
| hydrochloric | <chemistry> Pertaining to, or compounded of, chlorine and hydrogen gas; as, hydrochloric acid; chlorhydric. <chemistry> Hydrochloric acid, hydrogen chloride; a colourless, corrosive gas, HCl, of pungent, suffocating odour. It is made in great quantities in the soda process, by the action of sulphuric acid on common salt. It has a great affinity for water, and the commercial article is a strong solution of the gas in water. It is a typical acid, and is an indispensable agent in commercial and general chemical work. Synonym: muriatic, and chlorhydric, acid. Origin: Hydro-, 2 + hloric: cf. F. Hydrochlorique. Source: Websters Dictionary (01 Mar 1998) |
| hydrochloric acid | <chemical> Hydrochloric acid. Solutions of hydrogen chloride gas in water. It is a highly corrosive, strong mineral acid commonly used as a laboratory reagent. It is present endogenously as the acid component of gastric juice (hydrochloric acid, gastric see gastric acid). Chemical name: Hydrochloric acid (12 Dec 1998) |
| hydrochloride | <chemistry> A compound of hydrochloric acid with a base; distinguished from a chloride, where only chlorine unites with the base. Source: Websters Dictionary (01 Mar 1998) |
| hydrochlorothiazide | <chemical> A thiazide diuretic often considered the prototypical member of this class. It reduces the reabsorption of electrolytes from the renal tubules. This results in increased excretion of water and electrolytes, including sodium, potassium, chloride, and magnesium. It has been used in the treatment of several disorders including oedema, hypertension, diabetes insipidus, and hypoparathyroidism. Pharmacological action: antihypertensive agents, diuretics, thiazide. Chemical name: 2H-1,2,4-Benzothiadiazine-7-sulfonamide, 6-chloro-3,4-dihydro-, 1,1-dioxide (12 Dec 1998) |
| hydrocholecystis | Rarely used term for an effusion of serous fluid into the gallbladder. Origin: hydro-+ G. Chole, bile, + kystis, bladder (05 Mar 2000) |
| hydrocholeresis | Increased output of a watery bile of low specific gravity, viscosity, and solid content. Origin: hydro-+ G. Chole, bile, + hairesis, a taking (05 Mar 2000) |
| hydrocholeretic | Pertaining to hydrocholeresis. (05 Mar 2000) |
| hydrocodone | <chemical> Narcotic analgesic related to codeine, but more potent and more addicting by weight. It is used also as cough suppressant. Pharmacological action: analgesics, opioid, antitussive agents, narcotics. Chemical name: Morphinan-6-one, 4,5-epoxy-3-methoxy-17-methyl-, (5alpha)- (12 Dec 1998) |
| hydrocolloid | A gelatinous colloid in unstable equilibrium with its contained water, useful in dentistry for impressions because of its dimensional stability under controlled conditions. (05 Mar 2000) |
| hydrocolpocele | Accumulation of mucus or other nonsanguineous fluid in the vagina. Origin: hydro-+ G. Kolpos, bosom (vagina) (05 Mar 2000) |
| hydrocorallia | <zoology> A division of Hydroidea, including those genera that secrete a stony coral, as Millepora and Stylaster. Two forms of zooids in life project from small pores in the coral and resemble those of other hydroids. See Millepora. Origin: NL. See Hydra, and Coral. Source: Websters Dictionary (01 Mar 1998) |