Alphafetoprotein (AFP), a glycoprotein, consists of two sub- fractions with respect to its affinity for the lectin concanavalin A (con A). The percentage of the con A non-reactive AFP has been shown to be significantly lower in amniotic fluid from pregnancies associated with neural tube defect. Human AFP has also been shown to exist as a series or family of charge isomers, each isomer differing in isoelectric point. Charge microheterogeneity, as well as differences in con A binding, of other glycoproteins has been attributed to subtle differences in carbohydrate structure. Because AFP exhibits carbohydrate-microheterogeneity, it is reasonable to assume that the differences observed in the proportion of con A non-reactive AFP as a result of neural tube defect will reflect changes in the isoelectric pattern of AFP. Aliquots of amniotic fluid samples obtained during routine diagnostic amniocentesis in the second trimester of pregnancy will be used. Careful attention will be paid to the gestational age at which the sample is obtained. The total concentration of AFP will be determined in each sample by specific radioimmunoassay (RIA). The charge microheterogeneity of AFP will be determined by subjecting aliquots of amniotic fluid to chromatofocusing, a technique which separates proteins according to pI. The AFP in each fraction of the column will be measured by RIA. The immunoreactive peaks, corresponding to the various charge isomers, will be pooled. The carbohydrate-microheterogeneity of the charge isomers as well as native AFP in amniotic fluid will be further assessed by con A column chromatography. Differences in the charge microheterogeneity of AFP between normal and abnormal pregnancies will be compared. The results of the proposed study should increase our knowledge of the biochemical properties of human AFP and improve our ability for prenatal diagnosis of birth defects.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD022465-02
Application #
3322033
Study Section
Human Embryology and Development Subcommittee 2 (HED)
Project Start
1987-09-01
Project End
1990-08-31
Budget Start
1988-09-01
Budget End
1989-08-31
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Kansas
Department
Type
Schools of Medicine
DUNS #
016060860
City
Kansas City
State
KS
Country
United States
Zip Code
66160
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Keel, B A; Eddy, K B; Cho, S et al. (1992) Purified human alpha fetoprotein inhibits growth factor-stimulated estradiol production by porcine granulosa cells in monolayer culture. Endocrinology 130:3715-7
Keel, B A; Eddy, K B; Cho, S et al. (1991) Human alpha-fetoprotein purified from amniotic fluid enhances growth factor-mediated cell proliferation in vitro. Mol Reprod Dev 30:112-8
Leal, J A; Keel, B A (1991) A simple two-step purification of human and monkey alpha fetoprotein from amniotic fluid and serum. J Med Primatol 20:35-41
Keel, B A; Eddy, K B; Cho, S et al. (1991) Synergistic action of purified alpha-fetoprotein and growth factors on the proliferation of porcine granulosa cells in monolayer culture. Endocrinology 129:217-25
Leal, J A; Eddy, K B; Keel, B A (1991) Chromatofocusing profile of purified human alpha-fetoprotein and albumin differs from those of crude samples: effect of protein concentration of the elution of the sample. Anal Biochem 192:411-8
Leal, J A; Gangrade, B K; Kiser, J L et al. (1991) Human mammary tumor cell proliferation: primary role of platelet-derived growth factor and possible synergism with human alpha-fetoprotein. Steroids 56:247-51
Keel, B A; Harms, R L; Leal, J A et al. (1990) Characterization of human alpha fetoprotein charge microheterogeneity during fetal development. Mol Reprod Dev 27:281-7
Leal, J A; May, J V; Keel, B A (1990) Human alpha fetoprotein enhances epidermal growth factor proliferative activity upon porcine granulosa cells in monolayer culture. Endocrinology 126:669-71