ChemicalName stringlengths 3 104 | Definition stringlengths 12 791 |
|---|---|
pyrrolnitrin | 3-Chloro-4-(3-chloro-2-nitrophenyl)pyrrole. Antifungal antibiotic isolated from Pseudomonas pyrrocinia. It is effective mainly against Trichophyton, Microsporium, Epidermophyton, and Penicillium. |
pyrroloiminoquinones | Derivatives of QUINOLINES with fused PYRROLES and a keto group or INDOLEQUINONES with fused PIPERIDINES. |
pyruvaldehyde | An organic compound used often as a reagent in organic synthesis, as a flavoring agent, and in tanning. It has been demonstrated as an intermediate in the metabolism of acetone and its derivatives in isolated cell preparations, in various culture media, and in vivo in certain animals. |
pyruvates | Derivatives of PYRUVIC ACID, including its salts and esters. |
pyruvic acid | An intermediate compound in the metabolism of carbohydrates, proteins, and fats. In thiamine deficiency, its oxidation is retarded and it accumulates in the tissues, especially in nervous structures. (From Stedman, 26th ed) |
quartz | Quartz (SiO2). A glassy or crystalline form of silicon dioxide. Many colored varieties are semiprecious stones. (From Grant & Hackh's Chemical Dictionary, 5th ed) |
quassins | A group of degraded TRITERPENES which have lost ten carbons (8 from the side chain, C17, and one from C4) so have C20 skeletons which could be misinterpreted as DITERPENES. They especially occur in plants of the SIMAROUBACEAE family. |
quaternary ammonium compounds | Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2. |
quercetin | A flavonol widely distributed in plants. It is an antioxidant, like many other phenolic heterocyclic compounds. Glycosylated forms include RUTIN and quercetrin. |
quetiapine fumarate | A dibenzothiazepine and ANTIPSYCHOTIC AGENT that targets the SEROTONIN 5-HT2 RECEPTOR; HISTAMINE H1 RECEPTOR, adrenergic alpha1 and alpha2 receptors, as well as the DOPAMINE D1 RECEPTOR and DOPAMINE D2 RECEPTOR. It is used in the treatment of SCHIZOPHRENIA; BIPOLAR DISORDER and DEPRESSIVE DISORDER. |
quillaja saponins | Natural detergents made up of a heterogeneous mixture of molecules having a triterpenoid core structure. They vary in aglycone (sapogenin) and sugar moieties, including glucose. |
quinacrine | An acridine derivative formerly widely used as an antimalarial but superseded by chloroquine in recent years. It has also been used as an anthelmintic and in the treatment of giardiasis and malignant effusions. It is used in cell biological experiments as an inhibitor of phospholipase A2. |
quinacrine mustard | Nitrogen mustard analog of quinacrine used primarily as a stain in the studies of chromosomes and chromatin. Fluoresces by reaction with nucleic acids in chromosomes. |
quinapril | A tetrahydroisoquinoline derivative and ANGIOTENSIN CONVERTING ENZYME inhibitor that is used in the treatment of HYPERTENSION and HEART FAILURE. |
quinazolines | A group of aromatic heterocyclic compounds that contain a bicyclic structure with two fused six-membered aromatic rings, a benzene ring and a pyrimidine ring. |
quinazolinones | Chemicals with two conjoined aromatic rings incorporating two nitrogen atoms and one of the carbons oxidized with a keto oxygen. |
quinestrol | The 3-cyclopentyl ether of ETHINYL ESTRADIOL. After gastrointestinal absorption, it is stored in ADIPOSE TISSUE, slowly released, and metabolized principally to the parent compound. It has been used in ESTROGEN REPLACEMENT THERAPY. (From AMA Drug Evaluations Annual, 1992, p1011) |
quinic acid | An acid which is found in cinchona bark and elsewhere in plants. (From Stedman, 26th ed) |
quinidine | An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission. |
quinine | An alkaloid derived from the bark of the cinchona tree. It is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. Quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. It was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. Quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. The mechanisms of its antimalarial effects are not well understood. |
quinolinic acid | A metabolite of tryptophan with a possible role in neurodegenerative disorders. Elevated CSF levels of quinolinic acid are correlated with the severity of neuropsychological deficits in patients who have AIDS. |
quinolinic acids | Dicarboxylic acids with a PYRIDINE backbone. Quinolinic Acids are downstream products of the KYNURENINE pathway which metabolize amino acid TRYPTOPHAN. |
quinolizidine alkaloids | Alkaloids containing QUINOLIZIDINE ring structure. They are found in the genistoid legumes of FABACEAE (formerly Leguminosae) including genera LUPINUS and SOPHORA. |
quinolizidines | Saturated quinolizines that are two fused six-membered rings with a nitrogen atom at the ring fusion. They are biosynthesized in PLANTS by cyclization of a LYSINE coupled to CADAVERINE. Many of them are naturally occurring ALKALOIDS. |
quinolones | A group of derivatives of naphthyridine carboxylic acid, quinoline carboxylic acid, or NALIDIXIC ACID. |
quinones | Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups. |
quinpirole | A dopamine D2/D3 receptor agonist. |
quinuclidines | A class of organic compounds which contain two rings that share a pair of bridgehead carbon atoms and contains an amine group. |
quinuclidinyl benzilate | A high-affinity muscarinic antagonist commonly used as a tool in animal and tissue studies. |
quipazine | A pharmacologic congener of serotonin that contracts smooth muscle and has actions similar to those of tricyclic antidepressants. It has been proposed as an oxytocic. |
quisqualic acid | An agonist at two subsets of excitatory amino acid receptors, ionotropic receptors that directly control membrane channels and metabotropic receptors that indirectly mediate calcium mobilization from intracellular stores. The compound is obtained from the seeds and fruit of Quisqualis chinensis. |
rabeprazole | A 4-(3-methoxypropoxy)-3-methylpyridinyl derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS. |
rabies vaccines | Vaccines or candidate vaccines used to prevent and treat RABIES. The inactivated virus vaccine is used for preexposure immunization to persons at high risk of exposure, and in conjunction with rabies immunoglobulin, for postexposure prophylaxis. |
racemethionine | A preparation of METHIONINE that includes a mixture of D-methionine and L-methionine isomers. |
racepinephrine | A racemic mixture of d-epinephrine and l-epinephrine. |
raclopride | A substituted benzamide that has antipsychotic properties. It is a dopamine D2 receptor (see RECEPTORS, DOPAMINE D2) antagonist. |
radiation-protective agents | Drugs used to protect against ionizing radiation. They are usually of interest for use in radiation therapy but have been considered for other purposes, e.g. military. |
radiation-sensitizing agents | Drugs used to potentiate the effectiveness of radiation therapy in destroying unwanted cells. |
radioactive fallout | The material that descends to the earth or water well beyond the site of a surface or subsurface nuclear explosion. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed) |
radioactive pollutants | Radioactive substances which act as pollutants. They include chemicals whose radiation is released via radioactive waste, nuclear accidents, fallout from nuclear explosions, and the like. |
radioactive waste | Liquid, solid, or gaseous waste resulting from mining of radioactive ore, production of reactor fuel materials, reactor operation, processing of irradiated reactor fuels, and related operations, and from use of radioactive materials in research, industry, and medicine. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) |
radiopharmaceuticals | Compounds that are used in medicine as sources of radiation for radiotherapy and for diagnostic purposes. They have numerous uses in research and industry. (Martindale, The Extra Pharmacopoeia, 30th ed, p1161) |
radium | A radioactive element of the alkaline earth series of metals. It has the atomic symbol Ra and atomic number 88. Radium is the product of the disintegration of URANIUM and is present in pitchblende and all ores containing uranium. It is used clinically as a source of beta and gamma-rays in radiotherapy, particularly BRACHYTHERAPY. |
radon | A naturally radioactive element with atomic symbol Rn, and atomic number 86. It is a member of the noble gas family found in soil, and is released during the decay of RADIUM. |
radon daughters | Short-lived radioactive decay products of radon that include 216-Po, 214-Pb, 214-Bi, and 214-Po. They have an effective half-life of about 30 minutes and are solids that can deposit on the bronchial airways during inhalation and exhalation. This results in exposure of the respiratory airways to alpha radiation and can lead to diseases of the respiratory system, including lung cancer. (From Casarett and Doull's Toxicology, 4th ed, p740) |
raffinose | A trisaccharide occurring in Australian manna (from Eucalyptus spp, Myrtaceae) and in cottonseed meal. |
rafoxanide | Veterinary anthelmintic for grazing animals; used to treat fluke, hookworm and other infestations. |
raloxifene hydrochloride | A second generation selective estrogen receptor modulator (SERM) used to prevent osteoporosis in postmenopausal women. It has estrogen agonist effects on bone and cholesterol metabolism but behaves as a complete estrogen antagonist on mammary gland and uterine tissue. |
raltegravir potassium | A pyrrolidinone derivative and HIV INTEGRASE INHIBITOR that is used in combination with other ANTI-HIV AGENTS for the treatment of HIV INFECTION. |
ramipril | A long-acting angiotensin-converting enzyme inhibitor. It is a prodrug that is transformed in the liver to its active metabolite ramiprilat. |
ranitidine | A non-imidazole blocker of those histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers. |
rank ligand | A transmembrane protein belonging to the tumor necrosis factor superfamily that specifically binds RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B and OSTEOPROTEGERIN. It plays an important role in regulating OSTEOCLAST differentiation and activation. |
ranolazine | An acetanilide and piperazine derivative that functions as a SODIUM CHANNEL BLOCKER and prevents the release of enzymes during MYOCARDIAL ISCHEMIA. It is used in the treatment of ANGINA PECTORIS. |
rapeseed oil | PLANT OILS derived from RAPESEED species known as BRASSICA NAPUS. |
razoxane | An antimitotic agent with immunosuppressive properties. |
reactive nitrogen species | Nitrogenous products of NITRIC OXIDE synthases, ranging from NITRIC OXIDE to NITRATES. These reactive nitrogen intermediates also include the inorganic PEROXYNITROUS ACID and the organic S-NITROSOTHIOLS. |
reactive oxygen species | Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of SIGNAL TRANSDUCTION and GENE EXPRESSION, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS. |
reagent kits, diagnostic | Commercially prepared reagent sets, with accessory devices, containing all of the major components and literature necessary to perform one or more designated diagnostic tests or procedures. They may be for laboratory or personal use. |
reagent strips | Narrow pieces of material impregnated or covered with a substance used to produce a chemical reaction. The strips are used in detecting, measuring, producing, etc., other substances. (From Dorland, 28th ed) |
reboxetine | A morpholine derivative that is a selective and potent noradrenaline reuptake inhibitor; it is used in the treatment of DEPRESSIVE DISORDER. |
receptor-cd3 complex, antigen, t-cell | Molecule composed of the non-covalent association of the T-cell antigen receptor (RECEPTORS, ANTIGEN, T-CELL) with the CD3 complex (CD3 COMPLEX). This association is required for the surface expression and function of both components. The molecule consists of up to seven chains: either the alpha/beta or gamma/delta chains of the T-cell receptor, and four or five chains in the CD3 complex. |
receptor, erbb-2 | A cell surface protein-tyrosine kinase receptor that is overexpressed in a variety of ADENOCARCINOMAS. It has extensive homology to and heterodimerizes with the EGF RECEPTOR, the ERBB-3 RECEPTOR, and the ERBB-4 RECEPTOR. Activation of the erbB-2 receptor occurs through heterodimer formation with a ligand-bound erbB receptor family member. |
receptor, erbb-3 | A cell surface protein-tyrosine kinase receptor that is specific for NEUREGULINS. It has extensive homology to and can heterodimerize with the EGF RECEPTOR and the ERBB-2 RECEPTOR. Overexpression of the erbB-3 receptor is associated with TUMORIGENESIS. |
receptor, erbb-4 | A cell surface protein-tyrosine kinase receptor that has specificity for EPIREGULIN; BETACELLIN; NEUREGULINS; and HEPARIN-BINDING EGF-LIKE GROWTH-FACTOR. |
receptor for advanced glycation end products | A single-pass transmembrane CELL SURFACE RECEPTOR that binds ADVANCED GLYCATION END PRODUCTS to mediate cellular responses to both acute and chronic vascular inflammation in conditions such as ATHEROSCLEROSIS and DIABETES MELLITUS, TYPE 2. |
receptors, lymphocyte homing | Cell surface glycoproteins on lymphocytes and other leukocytes that mediate adhesion to specialized blood vessels called high endothelial venules. Several different classes of lymphocyte homing receptors have been identified, and they appear to target different surface molecules (addressins) on high endothelial venules in different tissues. The adhesion plays a crucial role in the trafficking of lymphocytes. |
receptors, purinergic p2x5 | A purinergic P2X neurotransmitter receptor found at high levels in the BRAIN and IMMUNE SYSTEM. |
reduced folate carrier protein | A ubiquitously expressed folic acid transporter that functions via an antiporter mechanism which is coupled to the transport of organic phosphates. |
reelin protein | It is an EXTRACELLULAR MATRIX serine protease that plays an important role in the development of the central nervous system. It regulates neuronal migration and microtubule function. |
relaxin | A water-soluble polypeptide (molecular weight approximately 8,000) extractable from the corpus luteum of pregnancy. It produces relaxation of the pubic symphysis and dilation of the uterine cervix in certain animal species. Its role in the human pregnant female is uncertain. (Dorland, 28th ed) |
remifentanil | A piperidine-propionate derivative and opioid analgesic structurally related to FENTANYL. It functions as a short-acting MU OPIOID RECEPTOR agonist, and is used as an analgesic during induction or maintenance of general anesthesia, following surgery, during childbirth, and in mechanically ventilated patients under intensive care. |
remoxipride | An antipsychotic agent that is specific for dopamine D2 receptors. It has been shown to be effective in the treatment of schizophrenia. |
renal agents | Drugs used for their effects on the kidneys' regulation of body fluid composition and volume. The most commonly used are the diuretics. Also included are drugs used for their antidiuretic and uricosuric actions, for their effects on the kidneys' clearance of other drugs, and for diagnosis of renal function. |
renin inhibitors | Agents that inhibit the activity of RENIN and cause VASODILATION. |
reproductive control agents | Substances used either in the prevention or facilitation of pregnancy. |
reserpine | An alkaloid found in the roots of Rauwolfia serpentina and R. vomitoria. Reserpine inhibits the uptake of norepinephrine into storage vesicles resulting in depletion of catecholamines and serotonin from central and peripheral axon terminals. It has been used as an antihypertensive and an antipsychotic as well as a research tool, but its adverse effects limit its clinical use. |
resin cements | Dental cements composed either of polymethyl methacrylate or dimethacrylate, produced by mixing an acrylic monomer liquid with acrylic polymers and mineral fillers. The cement is insoluble in water and is thus resistant to fluids in the mouth, but is also irritating to the dental pulp. It is used chiefly as a luting agent for fabricated and temporary restorations. (Jablonski's Dictionary of Dentistry, 1992, p159) |
resins, plant | Flammable, amorphous, vegetable products of secretion or disintegration, usually formed in special cavities of plants. They are generally insoluble in water and soluble in alcohol, carbon tetrachloride, ether, or volatile oils. They are fusible and have a conchoidal fracture. They are the oxidation or polymerization products of the terpenes, and are mixtures of aromatic acids and esters. Most are soft and sticky, but harden after exposure to cold. (From Grant & Hackh's Chemical Dictionary, 5th ed & Dorland, 28th ed) |
resins, synthetic | Polymers of high molecular weight which at some stage are capable of being molded and then harden to form useful components. |
resistant starch | Dietary starch and related high-molecular carbohydrate incapable of enzymatic hydrolysis in the SMALL INTESTINE and instead ferments in the COLON, producing SHORT-CHAIN FATTY ACIDS by-products. |
resistin | A 12-kDa cysteine-rich polypeptide hormone secreted by FAT CELLS in the ADIPOSE TISSUE. It is the founding member of the resistin-like molecule (RELM) hormone family. Resistin suppresses the ability of INSULIN to stimulate cellular GLUCOSE uptake. |
resorcinols | A water-soluble crystalline benzene-1,3-diol (resorcinol) and its derivatives. |
respiratory syncytial virus vaccines | Vaccines or candidate vaccines used to prevent infection with RESPIRATORY SYNCYTIAL VIRUSES. |
respiratory system agents | Drugs used for their effects on the respiratory system. |
resveratrol | A stilbene and non-flavonoid polyphenol produced by various plants including grapes and blueberries. It has anti-oxidant, anti-inflammatory, cardioprotective, anti-mutagenic, and anti-carcinogenic properties. It also inhibits platelet aggregation and the activity of several DNA HELICASES in vitro. |
reticulin | A scleroprotein fibril consisting mostly of type III collagen. Reticulin fibrils are extremely thin, with a diameter of between 0.5 and 2 um. They are involved in maintaining the structural integrity in a variety of organs. |
retinaldehyde | A diterpene derived from the carotenoid VITAMIN A which functions as the active component of the visual cycle. It is the prosthetic group of RHODOPSIN (i.e., covalently bonded to ROD OPSIN as 11-cis-retinal). When stimulated by visible light, rhodopsin transforms this cis-isomer of retinal to the trans-isomer (11-trans-retinal). This transformation straightens-out the bend of the retinal molecule and causes a change in the shape of rhodopsin triggering the visual process. A series of energy-requiring enzyme-catalyzed reactions convert the 11-trans-retinal back to the cis-isomer. |
retinal pigments | Photosensitive protein complexes of varied light absorption properties which are expressed in the PHOTORECEPTOR CELLS. They are OPSINS conjugated with VITAMIN A-based chromophores. Chromophores capture photons of light, leading to the activation of opsins and a biochemical cascade that ultimately excites the photoreceptor cells. |
retinoids | A group of tetraterpenes, with four terpene units joined head-to-tail. Biologically active members of this class are used clinically in the treatment of severe cystic ACNE; PSORIASIS; and other disorders of keratinization. |
retinyl esters | A carboxylic ester of retinol formed by condensation of the hydroxy group of retinol with a carboxy group. |
reverse transcriptase inhibitors | Inhibitors of reverse transcriptase (RNA-DIRECTED DNA POLYMERASE), an enzyme that synthesizes DNA on an RNA template. |
rhamnogalacturonans | Types of polysaccharides that are components of the plant cell wall pectin matrix. Rhamnogalacturonan I is characterized by a backbone of the repeating disaccharide (4)-alpha-D-galacturonic acid-(1,2)-alpha-L-rhamnose-(1,-) with many of the rhamnose residues substituted at C-4 with side chains of various neutral sugars linked together in various ways. Rhamnogalacturonan II type is complex, highly branched polysaccharide where the backbone consists exclusively of D-galacturonic acid units. |
rhamnose | A methylpentose whose L- isomer is found naturally in many plant glycosides and some gram-negative bacterial lipopolysaccharides. |
rhenium | A metal, atomic number 75, atomic weight 186.207, symbol Re. |
rh-hr blood-group system | Erythrocyte isoantigens of the Rh (Rhesus) blood group system, the most complex of all human blood groups. The major antigen Rh or D is the most common cause of erythroblastosis fetalis. |
rhodamine 123 | A fluorescent probe with low toxicity which is a potent substrate for ATP BINDING CASSETTE TRANSPORTER, SUBFAMILY B, MEMBER 1 and the bacterial multidrug efflux transporter. It is used to assess mitochondrial bioenergetics in living cells and to measure the efflux activity of ATP BINDING CASSETTE TRANSPORTER, SUBFAMILY B, MEMBER 1 in both normal and malignant cells. (Leukemia 1997;11(7):1124-30) |
rhodamines | A family of 3,6-di(substituted-amino)-9-benzoate derivatives of xanthene that are used as dyes and as indicators for various metals; also used as fluorescent tracers in histochemistry. |
rhodium | A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. |
rhodopsin | A purplish-red, light-sensitive pigment found in RETINAL ROD CELLS of most vertebrates. It is a complex consisting of a molecule of ROD OPSIN and a molecule of 11-cis retinal (RETINALDEHYDE). Rhodopsin exhibits peak absorption wavelength at about 500 nm. |
rho guanine nucleotide dissociation inhibitor beta | A rho GDP-dissociation inhibitor subtype that is highly expressed in hematopoietic cells and in LYMPHOCYTES. The expression of this subtype is associated with the regulation of CELL PROLIFERATION; TUMORIGENESIS; and APOPTOSIS. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.