| pyridoxine deficiency | A nutritional condition produced by a deficiency of pyridoxine in the diet, characterised by dermatitis, glossitis, cheilosis, and stomatitis. Marked deficiency causes irritability, weakness, depression, dizziness, peripheral neuropathy, and seizures. In infants and children typical manifestations are diarrhoea, anaemia, and seizures. Increasingly recognised as a cause is prolonged therapy with certain medications, among them isoniazid, cycloserine, and l-dopa. (12 Dec 1998) |
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| pyridoxine dependency with seizure | An inherited disorder (autosomal recessive) apparently associated with deficient brain type I glutamate decarboxylase; seizures can be controlled with vitamin B6. (05 Mar 2000) |
| pyridoxine phosphate phosphatase | <enzyme> Involved in metabolism of vitamin b(6) Registry number: EC 3.1.3.- Synonym: pyridoxal phosphate phosphatase, pyridoxamine phosphate phosphatase, pyridoxal-p hydrolase, pyridoxamine-p hydrolase, vitamin b(6)-phosphate phosphatase (26 Jun 1999) |
| pyridyl | <chemistry> A hypothetical radical, C5H4N, regarded as the essential residue of pyridine, and analogous to phenyl. Origin: Pyridine + -yl. Source: Websters Dictionary (01 Mar 1998) |
| pyriform | <anatomy> Pear-shaped. (15 Dec 1997) |
| pyriform aperture wiring | A method of wiring using the nasal bones at the area of the pyriform aperture for the stabilization of fractures of the jaw. (05 Mar 2000) |
| pyriform apparatus | A pear-shaped structure within the eggshell of certain tapeworms (family Anoplocephalidae), of uncertain function. (05 Mar 2000) |
| pyrilamine | <chemical> A histamine h1 antagonist. It has mild hypnotic properties and some local anaesthetic action and is used for allergies (including skin eruptions) both parenterally and locally. It is a common ingredient of cold remedies. Pharmacological action: anti-allergic agents, histamine h1 antagonists. Chemical name: 1,2-Ethanediamine, N-((4-methoxyphenyl)methyl)-N',N'-dimethyl-N-2-pyridinyl- (12 Dec 1998) |
| pyrilamine maleate | 2-[(2-dimethylaminoethyl) (p-methoxybenzyl)amino]pyridine maleate;an antihistaminic. Synonym: mepyramine maleate. (05 Mar 2000) |
| pyrimethamine | <drug> An oral antiprotozoa drug used in combination with sulphadiazine for toxoplasmosis. Possible side effects include severe allergic reactions and rashes, anaemia, leukopenia, thrombocytopenia, insomnia and diarrhoea. (15 Dec 1997) |
| pyrimidine | <biochemistry> A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They are planar and aromatic in character and include several nucleic acid constituents (cytosine, thymine, and uracil) and form the basic structure of the barbiturates. It is the parent compound of the pyrimidine bases of nucleic acid. (21 Jun 2000) |
| pyrimidine base | <biochemistry> A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They are planar and aromatic in character and include several nucleic acid constituents (cytosine, thymine, and uracil) and form the basic structure of the barbiturates. It is the parent compound of the pyrimidine bases of nucleic acid. (21 Jun 2000) |
| pyrimidine deoxyribonucleoside kinase | <enzyme> Consider also thymidine kinase (EC 2.7.1.21) or deoxycytidine kinase (EC 2.7.1.74) Registry number: EC 2.7.- Synonym: pyrimidine drn kinase (26 Jun 1999) |
| pyrimidine dimer | <biochemistry> A dimer product found in DNA chains damaged by ultraviolet irradiation. Most frequently thymidine dimers. They consist of two adjacent pyrimidine nucleotides, usually thymine nucleotides, in which the pyrimidine residues are covalently joined by a cyclobutane ring. These dimers stop DNA replication. (21 Jun 2000) |
| pyrimidine phosphoribosyltransferase | <enzyme> Pyrimidine monophosphate and pyrophosphate gives pyrimidine and phosphoribosyl pyrophosphate; acts with uracil, orotic acid or fluorouracil Registry number: EC 2.4.2.- (26 Jun 1999) |