7 Amniotic fluid alpha-fetoprotein concanavalin A-affinity molecular variants in the diagnosis of neural tube defects

1979 ◽  
Vol 12 (2) ◽  
pp. P3
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Concanavalin A ◽  
Alpha Fetoprotein ◽  
Molecular Variants

Concanavalin A binding of alpha-fetoprotein in amniotic fluid as an aid in the diagnosis of neural tube defects.

1981 ◽  
Vol 27 (10) ◽  
pp. 1658-1660 ◽  
Author(s):  
P K Buamah ◽  
P Taylor ◽  
A M Ward
Keyword(s):  
Spina Bifida ◽  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Concanavalin A ◽  
Gestational Age ◽  
Alpha Fetoprotein ◽  
Normal Outcome ◽  
Fetal Malformations ◽  
Open Spina Bifida

Abstract Concanavalin A nonreactive alpha-fetoprotein was determined in samples of amniotic fluid from 16 abnormal pregnancies complicated by anencephaly (7), open spina bifida (6), intra-uterine death (1), anencephaly with exomphalos (1), or open spina bifida with exomphalos (1), and in amniotic fluid from 50 normal pregnancies with gestational age between 13 and 24 weeks. In all 16 cases with fetal malformations, the proportion of nonreactive alpha-fetoprotein was significantly decreased (median 5.3%) as compared with amniotic fluid from pregnancies with a normal outcome (median 39.7%). The results confirm that this measurement is useful in the diagnosis of neural tube defects, especially when the concentration of alpha-fetoprotein in amniotic fluid is normal or only slightly above normal and gestational age is uncertain.

CONCANAVALIN-A REACTIVITY OF AMNIOTIC FLUID ALPHA-FETOPROTEIN IN DIAGNOSIS OF NEURAL-TUBE DEFECTS

The Lancet ◽  
1979 ◽  
Vol 314 (8148) ◽  
pp. 906 ◽  
Author(s):  
P. Hindersson ◽  
K. Toftager-Larsen ◽  
B. Nørgaard-Pedersen
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Concanavalin A ◽  
Alpha Fetoprotein

Comparison of amniotic fluid alpha-fetoprotein reactivity to Lens culinaris agglutinin and concanavalin A in crossed-affinity immunoelectrophoresis: ancillary tests in the prenatal diagnosis of severe fetal malformations.

1983 ◽  
Vol 29 (1) ◽  
pp. 21-24 ◽  
Author(s):  
K Toftager-Larsen ◽  
E Kjaersgaard ◽  
B Nørgaard-Pedersen
Keyword(s):  
Prenatal Diagnosis ◽  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Concanavalin A ◽  
Lens Culinaris ◽  
Alpha Fetoprotein ◽  
Fetal Abnormality ◽  
Lens Culinaris Agglutinin ◽  
Ancillary Test

Abstract Crossed-affinity immunoelectrophoresis of alpha-fetoprotein in amniotic fluid from 135 normal and 39 abnormal pregnancies (mainly neural-tube defects) was performed with a lectin, agglutinin from Lens culinaris. Results were compared with findings reported for another lectin, concanavalin A. Three fractions of alpha-fetoprotein were obtained by reaction with Lens culinaris agglutinin. The most weakly reactive fraction correlated strongly with the concanavalin A nonreactive fraction. With both lectins, significantly lower concentrations of these fractions were found in all samples from abnormal pregnancies than in those from normal pregnancies. In eight cases with a fetal abnormality the total alpha-fetoprotein concentrations were below the lower limit for abnormal samples. All eight samples revealed fractions weakly reactive with Lens culinaris agglutinin below the lower 0.1% limit for normal samples; seven of these samples had fractions nonreactive with concanavalin A below this limit. Although a decrease in the two described fractions in normal pregnancies was found with increasing gestational age, we find either method to be valuable as an ancillary test in the prenatal diagnosis of fetal neural-tube defects and other malformations.

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.

ELEVATED AMNIOTIC-FLUID ALPHA-FETOPROTEIN WITHOUT NEURAL-TUBE DEFECTS

The Lancet ◽  
1975 ◽  
Vol 306 (7945) ◽  
pp. 1141 ◽  
Author(s):  
N.J. Leschot ◽  
P.E. Treffers
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Alpha Fetoprotein

Evaluation of an enhanced luminescence assay for alpha-fetoprotein.

1986 ◽  
Vol 32 (11) ◽  
pp. 2066-2069 ◽  
Author(s):  
R John ◽  
R Henley ◽  
D Shankland
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Maternal Serum ◽  
Regression Equation ◽  
Alpha Fetoprotein ◽  
Reliable System ◽  
Analytical Recovery ◽  
Luminescence Assay ◽  
Enhanced Luminescence

Abstract We evaluated a two-site enhanced luminescence immunoenzymometric assay (Amerlite; Amersham International) for alpha-fetoprotein (AFP) in maternal serum and amniotic fluid. The assay is rapid, involving two incubations totalling 4 h. The working range of the assay for serum AFP is 5.5 to 750 kilo-int. units/L (CV less than 10%), with a sensitivity of detection of 0.2 kilo-int. unit/L. The regression equation for the Amerlite assay (y) and our in-house RIA procedure (x) was y = 0.816x + 2.9 (n = 142, r = 0.96). Analytical recovery of added AFP (code 72/227) at three concentrations was 86.7%. Serum AFP concentrations were measured at 15 to 18 weeks of gestation in subjects with normal pregnancies and in subjects whose pregnancies resulted in open neural tube defects; all of the latter had serum AFP concentrations greater than 2.5 multiples of the median. We find the Amerlite system to be an efficient, reliable system for screening for open neural tube defects without use of hazardous radioactive labels.

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