Biomaterial Database

Carbamoylated enzyme reversal as a means of predicting pyridostigmine protection against soman. 1989

R I Ellin, and A Kaminskis

U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010.

The inhibition of human and mammalian red blood cell (RBC) cholinesterase (AChE) in whole blood in the presence of added pyridostigmine has been examined. After the addition of pyridostigmine to animal and human blood, red cells were separated from plasma at varying intervals and their enzyme activity measured. An apparent rate constant (ke) was derived for the reaction sequence in which carbamate is released from AChE inhibited by pyridostigmine. The constant is a complex of the rates of decarbamoylation and reinhibition of AChE in the blood sample. Rate constants were also determined for the spontaneous reactivation (ks) of carbamoylated AChE in the species studied. Values of Ks were greater than Ke in corresponding species but varied little between species. Pretreatment of animals with pyridostigmine is known to be an effective therapy against organophosphorus compounds, including soman. The ranking of ke values in mammalian blood was the same as that for the protection against soman in animals: monkey greater than guinea-pig greater than rabbit greater than rat (ke = 0.15, 0.07, 0.05, 0.02 h-1, respectively). Since ke for human blood (0.20 h-1) was greater than that of monkey, pyridostigmine pretreatment would be expected to be an effective prophylaxis for soman in humans.

UI	MeSH Term	Description	Entries
D007202	Indicators and Reagents	Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)	Indicator,Reagent,Reagents,Indicators,Reagents and Indicators
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D011729	Pyridostigmine Bromide	A cholinesterase inhibitor with a slightly longer duration of action than NEOSTIGMINE. It is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants.	Mestinon,Pyridostigmine,Bromide, Pyridostigmine
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006207	Half-Life	The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.	Halflife,Half Life,Half-Lifes,Halflifes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000110	Acetylcholinesterase	An enzyme that catalyzes the hydrolysis of ACETYLCHOLINE to CHOLINE and acetate. In the CNS, this enzyme plays a role in the function of peripheral neuromuscular junctions. EC 3.1.1.7.	Acetylcholine Hydrolase,Acetylthiocholinesterase,Hydrolase, Acetylcholine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia