Reactivity of amniotic fluid alpha-fetoprotein with concanavalin A in relation to gestational age: clinical implications.

1980 ◽  
Vol 26 (12) ◽  
pp. 1656-1659 ◽  
Author(s):  
K Toftager-Larsen ◽  
E Kjaersgaard ◽  
J C Jacobsen ◽  
B Nørgaard-Pedersen
Keyword(s):  
Amniotic Fluid ◽  
Clinical Significance ◽  
Concanavalin A ◽  
Gestational Age ◽  
Normal Values ◽  
Alpha Fetoprotein ◽  
Clinical Implications ◽  
Fetal Malformation ◽  
Average Decrease ◽  
Normal Outcome

Abstract We used concanavalin A crossed-line affinity immunoelectrophoresis to determine the percentage of concanavalin A nonreactive alpha-fetoprotein in amniotic fluid samples from pregnancies with normal and abnormal fetuses. In 167 samples from pregnancies with a normal outcome and normal values for total alpha-fetoprotein concentration in amniotic fluid the percentage decreased from a median value of 27.4% in the 13th week to 8.5% in the 21st week of gestation, and a statistically significant (p < 0.001) average decrease of 1.7% per week was found from the 14th to the 19th week. A similar average decrease (2.2%) was found in 22 pregnancies from which two or more samples were obtained. The clinical significance of this decrease is discussed. Of 108 samples from patients with above-normal values for total alpha-fetoprotein and a normal outcome, seven had a total alpha-fetoprotein above recommended cut-off values, and only one of these had a low percentage of concanavalin A nonreactive alpha-fetoprotein. In contrast, for all 27 samples from pregnancies with a severe fetal malformation this percentage was low, even in one case where the total alpha-fetoprotein concentration was below the recommended cut-off value.

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.

Fetal-maternal distribution of ovine alpha-fetoprotein.

1978 ◽  
Vol 235 (1) ◽  
pp. E27 ◽  
Author(s):  
P C Lai ◽  
G J Mears ◽  
G R van Petten ◽  
D M Hay ◽  
F L Lorscheider
Keyword(s):  
Amniotic Fluid ◽  
Gestational Age ◽  
Maternal Serum ◽  
Alpha Fetoprotein ◽  
Neonatal Development ◽  
Fetal Serum

The concentration of ovine alpha-fetoprotein (AFP) was determined in sheep fetal, maternal, and neonatal sera and amniotic fluid by radioimmunoassay. The fetal serum AFP concentration was highest during the first third of pregnancy and continued to decline with fetal and neonatal development. Total fetal synthesis of AFP was highest during the late middle and early latter third of pregnancy. Amniotic fluid AFP concentration was highest during the early middle third of pregnancy. Maternal serum AFP was not elevated above nonpregnant control levels during the first two-thirds of pregnancy, but instead showed a tendency to be elevated only during the last third of pregnancy. The fetal physiological distributions of ovine and human AFP in fetal serum and amniotic fluid appear to be similar, whereas in maternal serum the pattern of AFP levels differs in the two species as a function of gestational age.

Implementation of a screening program for diagnosing open neural tube defects: selection, evaluation, and utilization of alpha-fetoprotein methodology.

1986 ◽  
Vol 32 (10) ◽  
pp. 1812-1817 ◽  
Author(s):  
R L Christensen ◽  
M R Rea ◽  
G Kessler ◽  
J P Crane ◽  
R Valdes
Keyword(s):  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defect ◽  
Gestational Age ◽  
Screening Program ◽  
Maternal Serum ◽  
Alpha Fetoprotein ◽  
Standard Curve ◽  
Analytical Recovery ◽  
Commercial Kit

Abstract We evaluated and compared three different commercial kit immunoassays for alpha-fetoprotein (AFP) before we implemented our neural tube defect screening program. Each kit can be used with either serum or amniotic fluid. Analytical recovery ranges for AFP reference sera within each kit's standard curve limits (in kilo-int. units/L) were 97-108% (7.5-180) for the Kallestad kit, 77-101% (21.8-436) for Amersham, and 92-100% (0-177) for Hybritech. CVs, within each manufacturer's standard-curve limits, for combined intra-assay (amniotic fluid pools) and inter-assay (kit serum controls) averaged 3.6-7.3% (Kallestad), 2.4-9.3% (Amersham (y) kit results showed a correlation of r = 0.97, y = 1.05x + 5.5 kilo-int. units per liter of maternal serum (n = 66; range, 2.0-98.5). Gestational age did not influence these assay correlations. The Kallestad AFP assay demonstrated a maternal serum positivity rate of 2.9% at greater than or equal to 2.5 (n = 655) and 8.9% at less than 0.5 (n = 423) multiples of the median. All kits performed well analytically.

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

scholarly journals Affinity Chromatography of Amniotic Fluid Alphafetoprotein Using Concanavalin A-Sepharose

1981 ◽  
Vol 18 (6) ◽  
pp. 350-352 ◽  
Author(s):  
Jennifer A Noyes ◽  
P J Wood
Keyword(s):  
Spina Bifida ◽  
Amniotic Fluid ◽  
Neural Tube ◽  
Neural Tube Defect ◽  
Concanavalin A ◽  
Con A ◽  
Potential Value ◽  
Significant Difference ◽  
Normal Outcome ◽  
Chromatography Columns

We measured Concanavalin A (Con A) non-binding alphafetoprotein in amniotic fluid from 21 normal pregnancies and 20 abnormal pregnancies (complicated by anencephaly, spina bifida, or exomphalos) using small Con A-sepharose chromatography columns. There was a highly significant difference between percentage non-binding alphafetoprotein levels for pregnancies with a normal outcome (mean result 32%; range 18–47%) and pregnancies complicated by a neural tube defect or exomphalos (mean 14%; range 7–20%). The test is therefore of potential value in cases where there is uncertainty over the interpretation of total amniotic fluid alphafetoprotein levels.

Sign in / Sign up

Export Citation Format

Share Document