Automated Determinationof CholinesteraseActivityin Plasma and ...

1 downloads 0 Views 731KB Size Report
deficiency (1) with the risk ofprolonged apnea after anesthe- sia with ..... methods for pseudocholinesterase and red cell (true) cholinesterase. Clin Chem 1971 ...
CLIN. CHEM. 35/1, 77-80 (1989)

Automated Determinationof CholinesteraseActivityin Plasma and Erythrocytesby FlowInjectionAnalysis,and Applicationto IdentifySubjectsSensitiveto Succinyicholine P. Laln#{233}-Cessac, A. Turcant, and P. AllaIn This automated spectrophotometnc method for determination of cholinesterase activity in erythrocytes and plasma is based on measurement of the choline produced at 30 #{176}C by the hydrolysis of acetyl-, butyryl-, or succinylcholine. Blanks, standards, and samples are prepared by a Gilson robotic unit. Use of flow-injection analysis for detection allows use of smaller volumes of reagent and sample. We applied this method to the study of 91 healthy subjects and members of two families with succinyicholine sensitivity. Results with use of the three different substrates for determination of activity in plasma correlated well (r >0.94). Results for plasma and erythrocytes from healthy subjects are lower in women 50 years or men. Values for plasma obtained with succinylcholine substrate (range: 31 to 100 U/L) allow detection of very sensitive subjects-AA phenotypes (50. We compared results by use of the nonparametric Kruskall-Wallis H-test or the Mann-Whitney U-test. Simple linear regression was used to compare the different substrates for PCE determination.

Table 1. Summary of the Assay Procedure Vol, p1.

Test

Blank

100

100

5 0 0 10

0 5 0 10

0 0 5 10

Incubate at 30 #{176}C for 20 mm 100 100

100

Buffer Sample Distilledwater Cholinesolutions Substrate Buffer Physostigmine Colorreagent

Standard 100

10 10 50 50 Incubateat 30 #{176}C for 20 mm Inject 70 pL, measure absorbance at 500 nm

between-day

study for

EACE

showed

an important

10 50

loss of

activity as early as the first week. For plasma determination, the between-day CVs were: PACE 7%, PBCE 5%, and PSCE 3.5%. In women, the variance study according to Kruskall-

Wallis H-test indicated a significant difference between age classesin the values for plasma (P