ROLE OF AMNIOTIC FLUID ACETYLCHOLINESTERASE IN SCREENING FOR NEURAL TUBE DEFECTS

The Lancet ◽  
1981 ◽  
Vol 317 (8216) ◽  
pp. 391 ◽  
Author(s):  
Ray Garry ◽  
John Atkins ◽  
S.J. Richardson ◽  
Brian Webb
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects

Role of amniotic fluid homocysteine level and of fetal 5,10-methylenetetrahydrafolate reductase genotype in the etiology of neural tube defects

2000 ◽  
Vol 90 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Katharine D. Wenstrom ◽  
Gary L. Johanning ◽  
John Owen ◽  
Kelley E. Johnston ◽  
Shannon Acton ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Homocysteine Level

A Potential Systematic Error in Using Lysivane as Inhibitor in the Measurement of Amniotic Fluid Acetylcholinesterase by the Ellman Method

1983 ◽  
Vol 20 (3) ◽  
pp. 159-162 ◽  
Author(s):  
B A Webb ◽  
S J Richardson ◽  
R Garry ◽  
J Atkins
Keyword(s):  
Enzymatic Hydrolysis ◽  
Amniotic Fluid ◽  
Systematic Error ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Acidic Solution ◽  
Rate Of Increase ◽  
Background Absorption ◽  
Low Levels ◽  
Hydrolysis Of

The measurement of low levels of cholinesterase or acetylcholinesterase by the Ellman method requires correction for a non-enzymatic increase in absorption at 412 mμ that is due both to non-enzymatic hydrolysis of the acetylthiocholine substrate and to modification of the colour reagent. The rate of increase in absorption is dependent on temperature and pH. Addition of an acidic solution of lysivane to the assay solution for selective measurement of amniotic fluid acetylcholinesterase gives rise to a shift in pH; the use of methanol is suggested as an easier method of dissolving the inhibitor and does not affect the pH of the assay, obviating any need to redetermine the background absorption. There is, however, no improvement in ability of the method to predict pregnancies associated with neural-tube defects.

scholarly journals Neural tube defects and elevated homocysteine levels in amniotic fluid

1995 ◽  
Vol 172 (5) ◽  
pp. 1436-1441 ◽  
Author(s):  
Régine P. Steegers-Theunissen ◽  
Godfried H. Boers ◽  
Henk J. Blom ◽  
Jan G. Nijhuis ◽  
Chris M.G. Thomas ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects

Acetylcholinesterase and fetal malformations: modified qualitative technique for diagnosis of neural tube defects.

1981 ◽  
Vol 27 (1) ◽  
pp. 61-63 ◽  
Author(s):  
J E Haddow ◽  
M E Morin ◽  
M S Holman ◽  
W A Miller
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
False Positive ◽  
Alpha Fetoprotein ◽  
Blind Study ◽  
Fetal Malformations ◽  
Qualitative Technique ◽  
Single Blind ◽  
Positive Results

Abstract A single-blind study involving amniotic-fluid samples from 214 pregnancies of known outcome confirms that an electrophoretically distinct isoenzyme of acetylcholinesterase is associated with fetal open neural tube defects. Furthermore, only one of 13 amniotic-fluid samples with false-positive results for alpha-fetoprotein showed the characteristic isoenzyme, indicating that qualitative acetylcholinesterase assessment can decrease the proportion of false positives from the alpha-fetoprotein assay. We have also identified this characteristic isoenzyme in amniotic fluids from pregnancies in which other serious fetal defects occurred. A detailed electrophoresis protocol for identifying this characteristic isoenzyme is described.

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