title: Reactivity of amniotic fluid alpha-fetoprotein with concanavalin A-sepharose in pre-natal diagnosis of fetal malformations.
abstract: The proportion of concanavalin A-non-reactive alpha-fetoprotein was determined in 215 amniotic fluid samples from second trimester pregnancies. the median percentage for concanavalin A-non-binding alpha-fetoprotein was 35.5% at the 15th week and 32.2% at the 18th gestational week. Nineteen of the 23 pregnancies with various fetal malformations showed highly elevated total alpha-fetoprotein levels. In this group, the value for non-reactive alpha-fetoprotein was below the normal range in 12 out of 13 samples collected at 15-17 weeks of pregnancy and in four out of six samples at 18-19 weeks. Four pathological pregnancies had only moderately elevated total alpha-fetoprotein levels (5.3-7.9 SD above the mean) and two of these samples had a low percentage of the concanavalin A-non-binding fraction. The amniotic fluid alpha-fetoprotein concentration was between 3 and 5 SD and over 5 SD above the mean in four and seven normal pregnancies, respectively. The concanavalin A-fractionation classified correctly 10 out of these 11 cases. The results indicate that the determination of the proportion of concanavalin A-non-binding alpha-fetoprotein is a useful supplementary test to the total alpha-fetoprotein assay.
mesh_terms: D000649:Amniocentesis; D000653:Amniotic Fluid / Q000032:analysis*; D002846:Chromatography, Affinity; D000013:Congenital Abnormalities / Q000175:diagnosis*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D011952:Receptors, Concanavalin A / Q000032:analysis*; D012685:Sepharose / Q000031:analogs & derivatives*; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D011952:Receptors, Concanavalin A; D000509:alpha-Fetoproteins; C028326:concanavalin A-sepharose; D012685:Sepharose