PubMed · 8073266
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
H Varmus. 1994-09-02. Embryo research guidelines.. https://doi.org/10.1126/science.8073266
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
We have shown for the first time that the microsomal glucose-6-phosphatase enzyme protein is present in human embryonic and fetal red blood cells and the ontogeny of its expression has been determined. In the earliest embryos, red cells are predominantly of the primitive megaloblastic type. Circulating red cells in the primitive megaloblastic series are predominantly nucleated and glucose-6-phosphatase immunopositive. Non-nucleated, immunoreactive megaloblastic cells are in a minority. In fetuses > 12 weeks gestation, the erythrocytes are of the definitive normoblastic series and in the transitional period of switch-over in late embryonic-early fetal life, up to 30% of glucose-6-phosphatase immunopositive cells are definitive normoblastic in type, with a variable contribution from nucleated and non-nucleated cells. Thereafter, the number of immunopositive cells in the definitive normoblastic series decreases such that after 12 weeks gestation it is less than 5%. The fact that a predominantly hepatic protein in adults (glucose-6-phosphatase) is present in embryonic and fetal red blood cells, particularly nucleated red cells, raises the possibility of diagnosis of disorders of liver protein expression in nucleated fetal red cells isolated from the first trimester maternal circulation.
OBJECTIVE: Our purpose was to evaluate the origin of alpha-fetoprotein in the maternal circulation and coelomic fluid of pregnancies with an empty gestational sac on first-trimester ultrasonographic examination. STUDY DESIGN: The alpha-fetoprotein level and the affinity of alpha-fetoprotein for concanavalin A Sepharose was measured between 8 and 11 weeks of gestation in the maternal serum and coelomic fluid of nine pregnancies complicated by an empty gestational sac and of 27 normal pregrancies. RESULTS: The maternal serum alpha-fetoprotein level in patients with an empty gestational sac was high in seven cases and normal in two cases. In these cases the median level was significantly (p < 0.01) higher in the serum and lower in the coelomic fluid compared with normal pregnancies. In eight cases of the nine pregnancies with an empty sac, > 50% of alpha-fetoprotein molecules in the coelomic fluid were of the concanavalin A nonreactive fraction, whereas in one case the coelomic fluid sample contained < 5% of this fraction. A similar distribution was found in the corresponding serum samples. CONCLUSION: Normal or high maternal serum AFP levels and alpha-fetoprotein molecules predominantly of yolk sac origin in the coelomic fluid of pregnancies with an empty gestational sac on ultrasonography provide further evidence that the most likely explanation for this feature is the early death of the embryo with persistence of the placental tissue.