Identification of acetylcholinesterase and cholinesterase in amniotic fluid by immune absorption technique

Nørgaard‐Pedersen, Bent; Jensen, Søren; Wandrup, J.

doi:10.1002/pd.1970020404

Cited by 11 publications

(2 citation statements)

References 15 publications

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“…AChE in amniotic fluid was analyzed by Table 1 Reason for referral for amniocentesis polyacrylamide-gel-electrophoresis (Nsrgaard-Pedersen et al 1982) in all samples with a concentration of AFP above the 95% limit during the last part of the period. In 159 normal samples both parameters were available for comparison.…”

Section: Methodsmentioning

confidence: 99%

Con A non‐reactive fractions of human amniotic fluid alpha‐fetoprotein in prenatal diagnosis of fetal neural tube defects and fetal abdominal wall defects

Toftager-Larsen

Nørgaard‐Pedersen

1988

Clinical Genetics

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During a 6-year period 19647 consecutively received amniotic fluid samples were analyzed for the alpha-fetoprotein (AFP) concentration. In samples with an AFP concentration above the 95% upper normal limit the fraction of AFP non-reactive with concanavalin A (con A) was determined by crossed affinity immunoelectrophoresis. Of 436 ,samples from normal pregnancies with a moderate elevation of AFP (between the 95% limit and 2.5 times the median) the con A fraction was normal in 92 to 98% ofthe cases, depending on the gestational age. At significantly elevated AFP concentrations (above 2.5 times the median), the fractions were normal in 78% of the 50 cases with a normal outcome. In 80 of 89 cases of fetal malformations, abnormally low fractions were found, and in all 19 cases of abdominal wall defects and congenital nephrosis the fractions were low. No significant difference was found in the sensitivity for detection of fetal malformations by con A analysis compared to quantitative analysis for acetylcholinesterase (AChE). However, significantly more false positive results were found in nomal pregnancies for the con A analysis compared to the AChE analysis. Both analyses performed significantly better than ultrasound scanning in terms of sensitivity. It is concluded that AChE is the test of choice in prenatal diagnosis of fetal neural tube defects. However, a sensitivity of 1.00 and a predictive value of a negative test of 1 .OO were found for the con A analysis for fetal abdominal wall defects.The AchE analysis performed less well in this context.

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Section: Methodsmentioning

confidence: 99%

Con A non‐reactive fractions of human amniotic fluid alpha‐fetoprotein in prenatal diagnosis of fetal neural tube defects and fetal abdominal wall defects

Toftager-Larsen

Nørgaard‐Pedersen

1988

Clinical Genetics

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“…However, even for a contamination of 10% of foetal or adult erythrocytes, lysed by freezing and thawing, no band of acetylcholinesterase activity was seen in the gel (80); this result is possibly due to size-related exclusion from the gel pores, leaving the acetylcholinesterase-containing membrane fragments at the application site of the gel (62). Therefore, lysis of red cells contaminating an amniotic fluid sample might give rise to false positive results in the gel test.…”

Section: Substances Interfering With the Gel Testmentioning

confidence: 99%

Reviews

1990

Clinical Chemistry and Laboratory Medicine

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This review discusses the interference in clinical chemical analysis caused by autoantibodies and by antibodies to foreign antigens. The nature of these disturbances, their occurrence, prevalence, and detection, the different ways in which they are manifested, the clinical consequences of the failure to recognize such interference, and finally methods for avoiding these disturbances are discussed.Interference by cold agglutinins in the automatic determination of the erythrocyte count, interference by cryoglobulins in the determination of the leukocyte count, and EDTA-induced thrombocyte agglutination are well documented as sources of error in the analysis of haematological parameters.Enzyme determinations may be affected by the occurrence of macro-complexes of the measured enzyme with immunoglobulins. This type of interference, for example, may occur in the determination of amylase and creatine kinase.Immunoassays for the determination of hormones or tumour markers are sensitive to autoantibodies and heterophilic antibodies. The former are particularly important in the determination of thyroid hormones, where the interference is method-dependent. In several immunoassays, interference by heterophilic antibodies can be abolished by the addition of non-immune serum.Finally, rheumatoid factors, antibodies administered for therapeutic purposes, and monoclonal gammopathies are possible sources of interference in the determination of various analytes.The present discussion presents a selection of impor-Automated cell counting is now an indispensable techtant interfering factors, which can arise in the labo-nique in the determination of haematological paramratory routine, with emphasis on antibodies as the eters. Used routinely, automatic cell counters yield Summary: The concentration of amniotic fluid acetylcholinesterase activity is elevated in cases of foetal open malformations, the levels being higher in cases of open neural tube defects than in cases of abdominal wall defects. Determination of amniotic fluid acetylcholinesterase activity is an established procedure for the antenatal diagnosis of foetal neural tube defects. Performance data, technical advantages and limitations for three procedures for the determination of acetylcholinesterase activity are reviewed in this paper: an immunoassay, a gel electrophoretic procedure and a spectrophotometric procedure. An immunoassay using the monoclonal antibody 4F19 and the gel electrophoretic procedure show nearly identical diagnostic performances, with detection rates for open spina bifida close to 100% and overall false positive rates of approximately 0.2%. The spectrophotometric procedure is not suitable for the antenatal diagnosis of foetal open neural tube defects and abdominal wall defects. It is possible to distinguish open neural tube defects from abdominal wall defects by determination of the ratio of acetylcholinesterase activity to butyrylcholinesterase activity, either by combining the 4F19 immunoassay with a butyrylcholinesterase immunoassay or by gel electr...

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Glial fibrillary acidic protein in amniotic fluids from pregnancies with fetal neural tube defects

1984

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The glial fibrillary acidic protein (GFAP) is the subunit protein of intermediate filaments in astrocytes and closely related cell types. By means of an enzyme immunoassay we have determined the concentration of GFAP in amniotic fluids from normal pregnancies and from pregnancies complicated by various fetal malformations. The group of 20 cases of fetal anencephaly had a significantly higher mean amniotic fluid GFAP concentration (115 micrograms/l +/- 133.6 (S.D.), range 6-378 micrograms/l) than the control group of 117 normal pregnancies (13 micrograms/l +/- 5.5 (S.D.), range 0-31 micrograms/l), (P less than 0.001). Two cases of fetal encephalocele likewise had very high amniotic fluid GFAP concentrations. None of the other cases of fetal malformations investigated, including 12 cases of spina bifida, had increased amniotic fluid GFAP concentrations. We conclude that determination of the amniotic fluid GFAP concentration may give additional information in the prenatal diagnosis of fetal nervous system malformations.

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Identification of acetylcholinesterase and cholinesterase in amniotic fluid by immune absorption technique

Cited by 11 publications

References 15 publications

Con A non‐reactive fractions of human amniotic fluid alpha‐fetoprotein in prenatal diagnosis of fetal neural tube defects and fetal abdominal wall defects

Con A non‐reactive fractions of human amniotic fluid alpha‐fetoprotein in prenatal diagnosis of fetal neural tube defects and fetal abdominal wall defects

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Glial fibrillary acidic protein in amniotic fluids from pregnancies with fetal neural tube defects

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