The influence of ketamine upon human plasma cholinesterase (E.C. 3.1.1.8) was determined by means of a colorimetric assay technique at 25 degrees C, pH 7.7 with butyrylthiocholine as substrate. Ketamine caused a reversible inhibition of cholinesterase (pI50= 2.75; apparent Ki=4.94X10(-4) M). The kinetic analysis of the inhibitory action revealed a mixed competitive/non-competitive type of mecha...

The aim of this study was to determine whether there was any relationship between body fat and pseudo(or plasma) cholinesterase. Hutchinson, McCance & Widdowson (I~sI), in reporting their studies of undernutrition and feeding, pointed out that, at the end of rehabilitation when men became ‘fat’, the average pseudo-cholinesterase was higher than normal. It therefore seemed of interest to investi...

Fenitrothion (Sumithion), and organophosphorous insectide, was applied dermally to rats. Cholinesterase activity was measured in blood and brain. The concentration of the pesticide in blood plasma and acetylcholine in brain were estimated at different intervals. The maximum concentration of Fenitrothion in the plasma was found at 4 hrs while significantly elevated levels of acetylcholine were p...

Cholinesterase (ChE) activity in birds is subject to interspecific and intraspecific species variations. Factors that influence enzyme activity have to be taken into account in order to obtain an accurate estimation of cholinesterase inhibition due to pesticide exposure in wild birds. This study evaluates variation of plasma cholinesterase activity in clay-colored robin (Turdus grayi) in relati...

A simple ultraviolet method has been developed for determining serum or plasma cholinesterase activity. The cholinesterase acts on acetylor butyrylthiocholine to release thiocholine, which reacts with 2,2’or 4,4’-dithiodipyridine, showing absorbance at 324 or 343 nm, respectively. The activity can be measured kinetically and alsoafter incubation for 3 to 5 mm at 20#{176} to 37#{176}C. A volume ...

Nineteen subjects were investigated as a result of apnoea following the administration of suxamethonium occurring in one member of the family. Examination of the blood for cholinesterase activity, dibucaine number, and fluoride number was carried out and the appropriate genotype determined. The significance of the genetic variation of plasma cholinesterase in relation to suxamethonium apnoea is...

A simple colorimetric method for determining serum or plasma cholinesterase has been described. The cholinesterase acts on acetyithiocholine to release thiocholine, which reacts with 5:5-dithiobis(2-nitrobenzoic acid) to produce a yellow color. The activity is measured after incubation for 3 mm. at 370; the reaction is stopped by the excess addition of quinidine sulfate. The difference in absor...