(n.) An organic base, especially one of a class of substances occurring ready formed in the tissues of plants and the bodies of animals.
Example Sentences:
(1) Thus, alkaloid and insecticide modifications share many features but differ in how much the conducting properties of the pore are changed and whether the channel can close reversibly while the toxin remains bound.
(2) A clear structure-mutagenicity relationship was observed in a series of aporphine alkaloids (aporphine, dehydroaporphine, 7-oxoaporphine and 4,5-dioxoaporphine), and 10,11-non-substituted aporphines were suggested to exert their mutagenicity through metabolic activation of the 10,11 positions, possibly as the 10,11-epoxides.
(3) A radioactive, photoactive Vinca alkaloid, N-(p-azido-[3,5-3H]-benzoyl)-N'-beta-aminoethylvindesine [( 3H]NABV) with pharmacological and biological activities similar to vinblastine was synthesized and used to identify specific Vinca alkaloid macromolecular interactions in calf brain homogenate by photoaffinity labeling.
(4) The comparative metabolism of the pyrrolizidine alkaloid (PA) senecionine was studied in vitro in incubations of rat, guinea pig, cow, horse, and sheep hepatic microsomes.
(5) They also displayed negative correlation between activities of protein-inhibitors and the total content of protein and alkaloids.
(6) Methods have been reviewed for alkylating agents, platinum compounds, antitumour antibiotics, antimetabolites, alkaloids, suramin, 1-hydroxy-3-amino-propylidene-1,1-bisphosphonate and tamoxifen.
(7) The resistant strains exhibited cross resistance to anthracycline antibiotics, vinca alkaloids, actinomycin D, colchicine.
(8) In mice treated with cepharanthine (Cepha), a biscoclaurine alkaloid, the number of T cells was increased in the parathymic lymph nodes (PtLNs) which are considered to be the specialized lymph nodes in local differentiation of T cells.
(9) The alkaloid tubulosine inhibits the process of peptide chain elongation by eukaryotic polysomes by specifically preventing the elongation-factor-2-dependent step of translocation.
(10) Cultured roots of Stephania cepharantha, which are rich sources of bisbenzylisoquinoline alkaloids, were fed 14C-labelled tyrosine, tyramine or dopamine.
(11) As a possible mechanism underlying the alterations of DRP, the functional consequences of atrophic changes of primary central afferent terminals are being discussed in terms of the close correlation between structure and function and the possible inferences of the electrophysiological reaction to the therapeutic application of Vinca alkaloids in the iontophoretic treatment of chronic intractable pain.
(12) The poisonous principles in tansy ragwort are pyrrolizidine alkaloids, which cause gradual alteration and necrosis of liver cells with replacement by fibrous tissue.
(13) In this study, the roots of Tabernaemontana heyneana Wall were examined and the isolation and identification of additional indole alkaloids and some pharmacological properties of coronaridine are described.
(14) The area ratios of four alkaloids (tropacocaine, norcocaine, cis-cinnamoylcocaine, and trans-cinnamoylcocaine) to cocaine are calculated for each sample.
(15) The main drugs with specific action on migraine include ergot alkaloids (ergotamine, dihydroergotamine), agonists (sumatriptan) or partial agonists (methysergide) at a specific subtype of 5-HT1-like receptors, beta-adrenoceptor antagonists (propranolol, metoprolol), calcium antagonists (flunarizine) and anti-inflammatory agents (indomethacin).
(16) Effects of solution variables on the binding and self-association explain the wide variation of reported apparent binding constants for Vinca alkaloids to tubulin.
(17) The concomitance of five previously reported trans-2,5-dialkyl-pyrrolidines along with small amounts of the cis isomers and N-methyl analogues makes the venom of M. indicum the most qualitatively diverse blend of alkaloids reported from an ant to date.
(18) Strong enhancement of delayed-type hypersensitivity (DTH) was observed after treatment with the active cyclophosphamide (CY) derivative Z 7557 or the plant alkaloid VP-16 at the site of sensitization.
(19) A total alkaloid and two purified alkaloid extracts of Alangium Vitiense were revealed by our experimental screening to be oncostatic on L1210 leukemia and two other lymphoid neoplasias in Mice.
(20) Possible mechanisms underlying these effects of insecticides on alkaloid-dependent uptake are discussed in light of a qualitative model formulated from these results and previous biochemical and electrophysiological studies.
Thebaine
Definition:
(n.) A poisonous alkaloid, C19H21NO3, found in opium in small quantities, having a sharp, astringent taste, and a tetanic action resembling that of strychnine.
Example Sentences:
(1) These results provide evidence for the enzymatic in vitro conversion by mammalian tissues of thebaine to morphine.
(2) Each step was evalutated for the yield of thebaine by use of 1-3H-thebaine and GLC.
(3) The method of drying and milling of tissue and the size of resultant particles were important factors in the quantitative recovery of thebaine.
(4) The minimum amount of thebaine that could readily be determined by the g.l.c.
(5) Potency was etorphine greater than morphine = codeine greater than thebaine.
(6) A method for the quantitative estimation of thebaine from P. bracteatum is presented.
(7) Shoot thebaine concentrations differed significantly for 18- and 37-week-old plants.
(8) The procedure gives base-line separation of thebaine without the need for gradient elution equipment, and can be completed within 12 min.
(10) some poppy plants were obtained that developed capsules richer in thebaine than the controls.
(11) Large doses of naltrexone precipitated a mild abstinence syndrome in dogs receiving thebaine chronically; however, no withdrawal abstinence syndrome was observed after abrupt withdrawal.
(12) Opial contains 50% morphine HCl and other opioids such as codeine, thebaine, papaverine, and noscapine etc.
(13) Attempts to use a codeinone intermediate gave poor yields; however, methylation of the potassium salt of codeine to give codeine methyl ether followed by oxidation with gamma-MnO2 gave thebaine in 67% yield from codeine.
(14) Oxymercuration of thebaine with mercuric acetate in refluxing methanol, followed by hydrolysis of the intermediate 7-acetomercurineopinone dimethyl ketal with 3 N acetic acid, or, alternatively, reduction of the organomercury compound with sodium borohydride and mild acid hydrolysis of the resulting neopinone dimethyl ketal, gives neopinone in 95-100% yields.
(15) A practical synthesis of thebaine and oripavine has been developed from codeine and morphine, respectively.
(16) Others opioids (dihydrocodeine, hydrocodone, oxycodone, and thebaine) are structurally similar to codeine and their metabolism (O-demethylation at the 3 position) might also be under genetic control.
(17) The method was applied successfully to the direct determination of thebaine in the Arya II population capsules of Papaver bracteatum Lindl.
(18) Thebaine isolated by this technique was shown to be pure, regardless of the age of plant or plant part from which it was obtained.
(19) One of the poppies, X7, (ca 5% thebaine) developed capsules consisting partly of polyploid tissue during the first and second year.
(20) The most potent drug in inhibiting the uptake of 5-HT (10 muM) by human platelets was methadone, followed by pentazocine>piminodine approximately pethidine approximately anileridine approximately cyclazocine approximately thebaine > dextropropoxyphene.