| HPLC | high-performance liquid chromatography; high-power liquid chromatography; high-pressure liquid chrom... |
|---|---|
| HT | Hashimoto thyroiditis; hearing test; hearing threshold; heart; heart transplantation, heart transpla... |
| HCD | health care delivery; heavy-chain disease; high-calorie diet; high-carbohydrate diet; homologous can... |
| HD | Haab-Dimmer [syndrome]; Hajna-Damon [broth]; Hansen disease; hearing distance; heart disease; helix ... |
| HEP | hemolysis end point; hepatoerythropoietic porphyria; high egg passage [virus]; high-energy phosphate... |
| vital ultraviolet | Rays necessary or helpful to normal growth; they promote calcium metabolism, are antirachitic in action, and have wavelengths between 3200 and 2900 A |
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| noeud vital | A circumscript region in the lower part of the medulla oblongata, near the apex of the calamus scriptorius, interpreted by M. Flourens (1858) as a nerve centre controlling respiration. Synonym: vital knot, vital node. Origin: Fr. (05 Mar 2000) |
| electro-vital | Derived from, or dependent upon, vital processes; said of certain electric currents supposed by some physiologists to circulate in the nerves of animals. Source: Websters Dictionary (01 Mar 1998) |
| forced vital capacity | Vital capacity measured with the subject exhaling as rapidly as possible; data relating volume, expiratory flow, and time form the basis for other pulmonary function tests, e.g., flow-volume curve, forced expiratory volume, forced expiratory time, forced expiratory flow. (05 Mar 2000) |
| blood urea nitrogen | Blood urea nitrogen (BUN) is a metabolic by product (in the liver) from the breakdown of blood, muscle and protein. Blood urea nitrogen can be measured from a simple venipuncture specimen. Abnormal elevation in the blood urea nitrogen can indicate renal disease, dehydration, congestive heart failure, gastrointestinal bleeding, starvation, shock or urinary tract obstruction (by tumour or prostate gland). Low BUN level can indicate liver disease, malnutrition or a low protein diet. Normal BUN levels should be between 7 and 20 mg/dl (milligrams per decilitre). (27 Sep 1997) |
| carbon-nitrogen ligases | <enzyme> Enzymes that catalyze the joining of two molecules by the formation of a carbon-nitrogen bond. Registry number: EC 6.3 (12 Dec 1998) |
| carbon-nitrogen ligases with glutamine as amide-n-donor | <enzyme> Enzymes that catalyze the joining of glutamine-derived ammonia and another molecule. The linkage is in the form of a carbon-nitrogen bond. Registry number: EC 6.3.5 (12 Dec 1998) |
| carbon-nitrogen lyases | <enzyme> Enzymes that catalyze the cleavage of a carbon-nitrogen bond by means other than hydrolysis or oxidation. Subclasses are the ammonia-lyases, the amidine-lyases, the amine-lyases, and other carbon-nitrogen lyases. Registry number: EC 4.3 (12 Dec 1998) |
| genes, nitrogen fixation | Regulatory and structural genes present in certain bacteria, algae and fungi that control the conversion of atmospheric nitrogen into biologically usable compounds; include nif structural genes (e.g., nifd, nifh) for nitrogenase and nitrate reductase as well as regulator genes nifa, nifb, ntra, ntrb, ntrc. Some are responsible for regulating transcription of genes involved in the assimilation of poor nitrogen sources in enteric bacteria. (12 Dec 1998) |
| rest nitrogen | The nitrogen content of other than protein bodies; e.g., about one-half the nonprotein nitrogen in the blood is contained in urea. Synonym: rest nitrogen. (05 Mar 2000) |
| heavy nitrogen | The less common stable nitrogen isotope, making up 0.37% of natural nitrogen. Synonym: heavy nitrogen. (05 Mar 2000) |
| nitrogen | <chemistry> A colourless nonmetallic element, tasteless and odorless, comprising four fifths of the atmosphere by volume. It is chemically very inert in the free state, and as such is incapable of supporting life (hence the name azote still used by French chemists); but it forms many important compounds, as ammonia, nitric acid, the cyanides, etc, and is a constituent of all organised living tissues, animal or vegetable. Symbol N. Atomic weight 14. It was formerly regarded as a permanent noncondensible gas, but was liquefied in 1877 by Cailletet of Paris, and Pictet of Geneva. Origin: L. Nitrum natron + -gen: cf. F. Nitrogene. See Niter. Source: Websters Dictionary (01 Mar 1998) |
| nitrogen-13 | A cyclotron-produced, positron-emitting radioisotope of nitrogen with a half-life of 9.97 minutes; used in protein metabolism studies and in positron-emission tomography. (05 Mar 2000) |
| nitrogen-14 | The common nitrogen isotope, making up 99.63% of natural nitrogen. (05 Mar 2000) |
| nitrogen-15 | The less common stable nitrogen isotope, making up 0.37% of natural nitrogen. Synonym: heavy nitrogen. (05 Mar 2000) |