Normal biology of alpha-fetoprotein

Serum LINC00152 and UCA1 in HCV-Induced Hepatocellular Carcinoma: Clinical Significance and Prognostic Value

Background

Despite significant advancements in the molecular characterization of hepatocellular carcinoma (HCC), no oncogene addiction has been discovered. Long noncoding RNAs (lncRNAs) have a lot of promise as cancer biomarkers. LINC00152 and UCA1 have shown potential as diagnostic, prognostic, and therapeutic targets for human cancers.

Aim

To investigate the diagnostic and prognostic potential of serum LINC00152 and UCA1 in hepatocellular carcinoma (HCC).

Methods

The expression levels of LINC00152 and UCA1 in blood samples from 120 patients (60 with HCC, 60 with liver cirrhosis) and 40 healthy subjects were assessed using real-time qRT-PCR.

Results

Serum LINC00152 and UCA1 expression were considerably higher in HCC patients compared to patients with liver cirrhosis and the healthy controls (p<0.001 and p<0.001 respectively). And their expressions in the liver cirrhosis group were significantly higher than in healthy controls. Both lncRNAs performed well in the ROC analysis, distinguishing HCC patients from patients with liver cirrhosis. Higher levels of LINC00152 expression were linked to lesions in both lobes of the liver (p=0.02), while higher levels of UCA1 expression were linked to vascular invasion and the late stage (p=0.01, p=0.03 respectively). The multivariate analysis showed that a high level of LINC00152 in the blood was an independent indicator of a bad outcome for HCC patients (HR=2.23, 95% CI= 1.30-5.29, p=0.03).

Conclusion

Serum LINC00152 and UCA1 expression were upregulated in patients with HCC, suggesting their use as non-invasive biomarkers for HCC. Furthermore, LINC00152 has the potential to serve as a prognostic indicator.

Diagnostic Performance of microRNA-122 and microRNA-224 in Hepatitis C Virus-Induced Hepatocellular Carcinoma (HCC)

Background and objectives: Hepatocellular carcinoma (HCC) is a potential health problem in Egypt because of the high prevalence of HCV infection. Using alpha-fetoprotein for diagnosis is unsatisfactory especially in early stages. Many studies showed that microRNAs (miRNA) expression may be associated with the development and progression of various types of cancer including HCC and it may serve as biomarkers for diagnosis. This study examined two miRNAs which are miRNA-122 and miRNA-224 if it could serve as biomarkers for diagnosis of HCC. Methods: This study included 20 patients with HCV-induced HCC and 20 patients with HCV-induced liver cirrhosis for comparison. As well as 20 healthy volunteers as controls. All participants were subjected to history taking, clinical examination, and determination of serum alpha-fetoprotein. Quantification of plasma miRNA-122 and miRNA-224 was done by real-time quantitative PCR. Results: Our results showed that levels of miRNA-122 were significantly lower in HCC group compared to the cirrhosis group and controls, while levels of miRNA-224 were significantly higher. The levels of both miRNAs have a correlation with tumor size. Moreover, the diagnostic accuracy of miRNA-122 (sensitivity 95%, specificity 81%, p-value <0.001) and of miRNA-224 (sensitivity 85%, specificity 79%, p-value <0.001) in discriminating patients with HCC from patients with liver cirrhosis were higher than that of alpha-fetoprotein (sensitivity 70%, specificity 70%, p-value <0.05). In addition, combining any one of these miRNAs with alpha-fetoprotein will increase the diagnostic accuracy compared to using each marker alone. Conclusion: miRNA-122 and miRNA-224 could serve as biomarkers for the diagnosis of HCC.

Brain barriers and functional interfaces with sequential appearance of ABC efflux transporters during human development

Adult brain is protected from entry of drugs and toxins by specific mechanisms such as ABC (ATP-binding Cassette) efflux transporters. Little is known when these appear in human brain during development. Cellular distribution of three main ABC transporters (ABCC1, ABCG2, ABCB1) was determined at blood-brain barriers and interfaces in human embryos and fetuses in first half of gestation. Antibodies against claudin-5 and -11 and antibodies to α-fetoprotein were used to describe morphological and functional aspects of brain barriers. First exchange interfaces to be established, probably at 4–5 weeks post conception, are between brain and embryonic cerebrospinal fluid (eCSF) and between outer surface of brain anlage and primary meninx. They already exclude α-fetoprotein and are immunopositive for both claudins, ABCC1 and ABCG2. ABCB1 is detectable within a week of blood vessels first penetrating into brain parenchyma (6–7 weeks post conception). ABCC1, ABCB1 and ABCG2 are present at blood-CSF barrier in all choroid plexuses from first appearance (7 weeks post conception). Outer CSF-brain interfaces are established between 9–11 weeks post conception exhibiting immunoreactivity for all three transporters. Results provide evidence for sequential establishment of brain exchange interfaces and spatial and temporal timetable for three main ABC transporters in early human brain.

Recurrence of extreme serum analytes in consecutive pregnancies and association with obstetrical outcomes. J Matern Fetal Neonatal Med 2017;32:85-91. [PMID: 28838266 DOI: 10.1080/14767058.2017.1371695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

OBJECTIVE

To evaluate if presence of extreme maternal serum biochemical analytes recurs in consecutive pregnancies. We hypothesized that presence of >1 extreme analyte in prior pregnancy is associated with increased risk of adverse pregnancy outcome in subsequent pregnancy.

METHODS

Retrospective cohort study of singleton pregnancies evaluated and delivered in 2 consecutive pregnancies (2011-2015). Adverse outcomes were defined as indicated preterm delivery before 37 completed weeks due to preeclampsia, fetal growth restriction or other complications.

RESULTS

First and second trimester maternal serum analytes were assessed in 1434 patients in 2 consecutive pregnancies. The presence of >1 extreme serum analyte in prior pregnancy significantly increased likelihood of >1 extreme analyte in subsequent pregnancy. The likelihood increased as number of prior extreme markers increased. In patients with normal outcomes and 2 or more extreme serum analytes in prior pregnancy, there was an increased incidence of adverse pregnancy outcomes in subsequent pregnancy with relative risk (RR) of 5.42 [95% CI 1.6-18.3].

CONCLUSIONS

The presence of more than 1 extreme serum marker in one pregnancy increases likelihood of recurrence in subsequent pregnancies. Risk of adverse outcomes in subsequent pregnancy can be evaluated based on biochemistry results as well as prior pregnancy outcomes.

Decrease of Alpha-fetoprotein in Patients with Cirrhosis Treated with Direct-acting Antivirals

Background and Aims: The lack of specificity has limited the role of serum alpha-fetoprotein (AFP) for hepatocellular carcinoma (HCC) screening among patients with cirrhosis related to hepatitis C virus (HCV) infection. We sought to examine whether AFP may decrease after achieving a sustained virological response (SVR) in patients with HCV-related cirrhosis. Methods: We performed a retrospective study of patients with HCV-related cirrhosis who were cured with direct-acting antiviral (DAA) therapy at the University of California, Los Angeles. Laboratory values, including serum AFP, were measured before and after completing the DAA treatment. Results: Fifty-six patients met the inclusion criteria, with median (interquartile range [IQR]) age of 67 (58-69) years and with 51.8% being male. All patients received DAA therapy without interferon. AFP decreased from median (IQR) 7.2 (4.2-13.4) ng/mL before DAAs to 4.2 (2.7-6.3) ng/mL at the end of treatment and 4.2 (2.9-6.8) ng/mL at 12 weeks after treatment (p < 0.001). Model for end-stage liver disease (MELD), fibrosis-4 (FIB4), and aspartate transaminase (AST) to platelet ratio index (APRI) scores at baseline were not significantly associated with AFP reduction. On multivariate analysis, platelet count, AST and total bilirubin at baseline were significantly correlated to AFP reduction (p = 0.04, 0.009 and 0.04, respectively). The higher the baseline AFP, the greater the reduction in AFP. There was no statistically significant correlation between baseline AFP and MELD, FIB4 or APRI scores. Conclusion: There was a significant decrease in AFP in patients with cirrhosis who achieved a SVR with DAAs. Given a reduction in AFP after DAA treatment, AFP should be further studied as a screening modality for HCC in patients with cirrhosis.

Characterization of alpha-fetoprotein levels in three dolphin species: development of sensitive immunoassays for analysis of the pregnancy-associated variations

A single radial immunodiffusion (SRID) assay and a chemiluminescent immunoassay (CLIA) were initially developed for alpha-fetoprotein (AFP) of the striped dolphin. Utilizing these developed assays, we investigated pregnancy-associated changes in the levels of AFP in the sera of fetuses and pregnant females of three dolphin species; samples were either collected from captive individuals or obtained as fishery by-products. The concentrations of AFP in the fetal serum ranged from 419.0 to 2026.3 μg/ml in the striped dolphin, 12.6 to 1218.7 μg/ml (for an AFP equivalent; eqAFP) in the common bottlenose dolphin and 770.6 to 3129.1 μg eqAFP/ml in the Risso's dolphin. AFP levels decreased with increased fetal size in fetuses over 20 cm in length. The concentrations of AFP in sera of pregnant females ranged from 7.18 to 8068.7 ng/ml in the striped dolphin, 6.6 to 1241.1 ng eqAFP/ml in the common bottlenose dolphin and 3.4 to 2868.7 ng eqAFP/ml in the Risso's dolphin. The levels in most pregnant females were equal to or lower than those found in males and nonpregnant individuals, although a few pregnant females exhibited extremely high levels (in the range of hundreds to thousands of nanograms per milliliter). Such high levels of AFP were not observed during pseudopregnancy. To our knowledge, this is the first report on basal profiles for serum AFP levels in small odontocetes. The profiles indicated that AFP may play a significant role during embryonic development, although maternal levels do not appear to be a diagnostic biomarker for monitoring pregnancy.

Abnormal second-trimester serum analytes are more predictive of preterm preeclampsia

OBJECTIVE

We sought to determine the association of abnormal second-trimester serum analytes with early preterm preeclampsia.

STUDY DESIGN

We conducted a retrospective study of 7767 subjects undergoing second-trimester serum aneuploidy screening. Values of maternal serum α-fetoprotein (AFP), β-human chorionic gonadotropin (hCG), and inhibin (INH) were calculated as multiples of the median (MoM) and evaluated by gestational age at delivery and occurrence of preeclampsia.

RESULTS

Of 459 (6.5%) cases of preeclampsia, 65 (14%) delivered <34 weeks and 394 (86%) delivered >34 weeks. Elevated AFP, hCG, and INH >2 MoM were associated with preeclampsia, and the odds ratio was higher for the development of preeclampsia <34 weeks than >34 weeks (odds ratio, 8.04 vs 2.91 for AFP, 3.6 vs 2 for hCG, and 4.17 vs 3.08 for INH, P < .001 for all). The higher the MoM for each analyte the greater the likelihood of preeclampsia.

CONCLUSION

Elevated AFP, hCG, and INH levels >2 MoM are associated with developing early preeclampsia, and the more elevated they are, the higher the likelihood.

Characterization of alpha-fetoprotein in fetal striped dolphin (Stenella coeruleoalba): purification of protein product and molecular cloning of the corresponding transcript

Alpha-fetoprotein (AFP) is a fetal glycoprotein that is known as a biomarker for monitoring pregnancy in many mammalian species. However, characterization of AFP has not yet been undertaken in any cetacean species. Here, we purified AFP from the serum of fetal striped dolphin by chemical precipitation followed by a combination of immunoadsorbent column chromatography and gel filtration. The molecular masses of native and denatured dolphin AFP were estimated to be ∼78,000 Da by gel filtration and ∼68,000 Da by SDS-PAGE, respectively, representing typical masses reported for mammalian AFPs. In fetal serum, only the AFP band (∼68,000 Da) appeared to be immunoreactive to an antiserum against purified dolphin AFP, indicating sufficient specificity for the development of an AFP immunoassay. Full-length cDNA encoding for the dolphin AFP was cloned from fetal liver and revealed an open reading frame comprising 610 amino acid residues, which included a putative signal peptide of 18 amino acid residues. This was followed by a sequence identical to the N-terminus of purified AFP. The deduced amino acid sequence of dolphin AFP showed more than 80% identity to those of other mammalian AFPs. To our knowledge, the present report represents the first identification and characterization of AFP from any cetacean species.

Inflammatory cytokines and antioxidants in midtrimester amniotic fluid: correlation with pregnancy outcome

OBJECTIVE

Elevated interleukin-6 (IL-6) level in midtrimester amniotic fluid is associated with preterm delivery. We hypothesized that, in patients with elevated IL-6, vitamin C and alpha-fetoprotein may provide protection from spontaneous preterm delivery through antioxidant functions.

STUDY DESIGN

Antioxidant potential of alpha-fetoprotein was assessed in vitro. Amniotic fluid was collected from a prospective cohort of patients who underwent midtrimester amniocentesis. In patients with IL-6 >600 pg/mL, alpha-fetoprotein, vitamin C, tumor necrosis factor-alpha, tumor necrosis factor receptors, and antioxidant capacity were compared between subjects with spontaneous preterm and term deliveries.

RESULTS

Alpha-fetoprotein demonstrated 75% the antioxidant capacity of albumin in vitro. Of 388 subjects, 73 women had elevated IL-6 levels. Among these subjects, alpha-fetoprotein, but not vitamin C, was significantly lower in 9 women with preterm birth. Antioxidant capacity correlated with vitamin C and tumor necrosis factor receptors, but not with alpha-fetoprotein or pregnancy outcome.

CONCLUSION

Amniotic fluid alpha-fetoprotein, but not vitamin C, may protect against preterm birth in patients with elevated midtrimester IL-6 levels.

Alterations of glycan branching and differential expression of sialic acid on alpha fetoprotein among hepatitis patients

The level of serum glycoproteins and their glycosylation pattern change in liver diseases including hepatocellular carcinoma (HCC). Some of them, especially alpha fetoprotein (AFP), serve as useful biomarkers for HCC. The present investigation showed high level of AFP in hepatitis B cirrhosis (HBV-LC) and hepatitis C cirrhosis (HCV-LC) patients. However, increase of AFP level was not significantly high in chronic hepatitis B (HBV-CH) as determined by ELISA using monoclonal anti-human AFP (mAb-AFP). The differential expression of sialic acid linkage was observed in HBV-CH and HCV-LC by ELISA; the former bound strongly with Sambucus nigra agglutinin (SNA), which has exclusive binding specificity for NeuAcα2-6-, whereas HCV-LC reacted preferably with Maackia amurensis agglutinin (MAA) which recognizes NeuAcα2-3-. There was significantly high glycan branching in HBV-LC and HCV-LC in comparison to controls as illustrated by concanavalin A. This was further confirmed by Phaseolus vulgaris erythroagglutinin (E-PHA) and Datura stramonium agglutinin (DSA). Enhanced fucosylation of AFP was observed in HBV-LC, HCV-LC and HCC patients by ELISA using fucose binding Aleuria aurantia lectin; however, maximum binding was found in HCC. Fucosylation with α1-6 linkage was further confirmed by Lens culinaris agglutinin (LCA). From the above results it is concluded that the changes in concentration of AFP, differential expression of sialic acid, increase of glycan branching and fucosylation have a prognostic value of hepatitis and it could be possible that lectin-based assay with AFP can aid in diagnosis of hepatitis diseases besides clinical examination and routine laboratory investigation.

Maternal serum markers of placental damage in uncomplicated dichorionic and monochorionic pregnancies in comparison with monochorionic pregnancies complicated by severe twin-to-twin transfusion syndrome and the response to fetoscopic laser ablation

OBJECTIVE

Twin-to-twin transfusion syndrome (TTTS) is a morbid perinatal condition associated with abnormal placentation and is treated by fetoscopic laser ablation (FLA). We assessed basal maternal serum alphafetoprotein (MSAFP) and free beta-human chorionic gonadotrophin (f-betaHCG) in uncomplicated dichorionic (DC) and monochorionic (MC) twin pregnancies and a cohort of MC twin pregnancies complicated by severe TTTS. Changes in MSAFP and f-betaHCG post-FLA were measured as markers of placental coagulation.

STUDY DESIGN

In a prospective case-cohort study, MC twins complicated by TTTS (n=23) were studied. A cohort of uncomplicated DC (n=12) and MC (n=6) twin pregnancies, which were appropriately grown for gestation with normal liquor volumes were also studied. Using solid phase, two site fluoroimmunometric assays, both MSAFP and f-betaHCG from uncomplicated and complicated cohorts were measured. Samples were taken, prior to FLA then at intervals after the procedures (6h, 24h and 1 week).

RESULTS

The median multiples of median (MoM) were not significantly different in uncomplicated DC twin pregnancies for MSAFP 1.85 (95% CI 1.62-2.34) or fbetaHCG 1.66 (95% CI 1.21-2.04) compared to uncomplicated MC twin pregnancies (MSAFP 1.40 (95% CI 1.16-2.58) and fbetaHCG 1.70 (95% CI 0.32-3.35)). However, the median MSAFP MoM in MC twin pregnancies complicated by severe TTTS was increased (MSAFP 3.10 (95% CI 2.67-4.43); p<0.05) with a more significant increase being noted in median fbetaHCG (MoM 5.75 (95% CI 5.22-9.12); p<0.0001) compared to uncomplicated twin pregnancies. Post-FLA, the median MSAFP increased significantly at 6h by 445% (636.65 U/ml (95% CI 616-1216.9 U/ml)) and remained elevated at 1 week (553.4 U/ml (95% CI 203.7-3020.8 U/ml; p=0.001)). No significant difference in median fbetaHCG was noted post-FLA (p=0.36). This rise in MSAFP appears unrelated to the number of placental anastomoses coagulated or the total energy used. Also, in the small cohort in which amniodrainage alone was performed no rise in MSAFP was noted.

CONCLUSIONS

MSAFP and fbetaHCG are increased in TTTS indicating an association with abnormal placentation. Post-FLA, a significant rise in MSAFP was noted for up to a week post-coagulation. This was not noted after amniodrainage.

Outcome of pregnancies at risk for neonatal hemochromatosis is improved by treatment with high-dose intravenous immunoglobulin

OBJECTIVES

Neonatal hemochromatosis is the result of severe fetal liver injury that seems to result from maternal-fetal alloimmunity. Women who have had an infant affected with neonatal hemochromatosis are at high risk in subsequent pregnancies for having another affected infant. This study was designed to determine whether therapy directed at limiting the severity of gestational alloimmunity can reduce the occurrence of severe neonatal hemochromatosis in infants of women at risk. A secondary objective was to use a prospectively collected data set to examine questions of vital interest about neonatal hemochromatosis.

METHODS

Women with a history of pregnancy ending in documented neonatal hemochromatosis were treated with intravenous immunoglobulin at 1 g/kg of body weight weekly from week 18 until the end of gestation. Extensive data were prospectively collected regarding the gestational histories of the subjects. The outcomes of treated pregnancies were compared with those of previous affected pregnancies, which were used as historical controls.

RESULTS

Forty-eight women were enrolled to be treated during 53 pregnancies. The gestational histories of these women demonstrated the high risk of occurrence of neonatal hemochromatosis: 92% of pregnancies at risk resulted in intrauterine fetal demise, neonatal death, or liver failure necessitating transplant. In contrast, with gestational therapy, the 53 at-risk gestations resulted in 3 failures and 52 infants who survived intact with medical therapy alone. When compared on a per-woman or per-infant basis, the outcome of gestation at risk for neonatal hemochromatosis was improved by gestational therapy.

CONCLUSIONS

Neonatal hemochromatosis seems to be the result of a gestational alloimmune disease, and occurrence of severe neonatal hemochromatosis in at-risk pregnancies can be significantly reduced by treatment with high-dose intravenous immunoglobulin during gestation.

Stem cell stages and the origins of colon cancer: a multidisciplinary perspective

Analysis of historical age-specific colorectal cancer rates, present day age-specific colonic adenoma prevalence and the few reports of direct measurements of genetic change in human tissues as a function of age in adults have led to a new set of hypotheses about carcinogenesis. A key observation, that the calculated rate of growth of preneoplasia is equal to the calculated growth rate of the juvenile colon, suggested that tumor initiation blocks the developmental step by which growing juvenile stem cells are transformed into or replaced by adult maintenance stem cells. In this hypothesis the slowly growing adenomatous polyps would simply be patches of highly organized juvenile tissue modified by the mechanical constraints of surrounding nongrowing adult tissue. As juvenile tissue presumably grows by net increase in stem cells creating crypts, tumor promotion could be achieved by transformation of an initiated stem cell into a fetal stem cell that would express the program of rapid net growth and differentiation into the heterogeneous cell types of fetal colonic organogenesis. (One additional interpretation of data from observations of point mutations in adult lung epithelium is that rates of genetic change in juvenile stem cells are markedly higher than in adult maintenance stem cells.) Unfortunately, the concept of a "stem cell" undergoing staged transitions in organ development and blocked or reverse transitions in carcinogenesis has lacked the physical embodiment of a cell that could be recognized, isolated, and analyzed. In an attempt to overcome this impediment we set reexamined fetal and adult colonic tissue, adenomas, and adenocarcinomas using a novel histological preparation method. Gostjeva then discovered that fetal and neoplastic tissues share a set of cells distinguished by specific nuclear morphotypes that appear to cooperate in creating the elements of the fetal organ, preneoplastic, and neoplastic lesions. In particular, microscopic examination of fetal gut at 5-7 wk gestation reveals tubular syncytia containing opened-mouthed, bell-shaped nuclei that account for some 30% of the nuclei in the protoorgan. These peculiar nuclei undergo both symmetric and asymmetric nuclear fissions, the latter creating all of the other nuclear morphotypes. These nuclear fissions are "amitotic" insofar as no general chromosome condensation is observed. Bell-shaped nuclei are rarely found in adult colonic crypt bases but are found in preneoplasia and neoplasia.

Disparate clinical presentation of neonatal hemochromatosis in twins

Neonatal hemochromatosis (NH) is a rare disease of gestation that results in fetal liver injury and extrahepatic siderosis. The etiology of NH is not fully understood. However, the rate of recurrence of NH in the pregnancy after an affected one is approximately 80%. A spectrum of liver disease has been recognized, spanning from liver failure in the fetus or neonate to infants that survive with medical therapy. Here we report on 2 sets of fraternal twins, each set with a gross disparity in the severity of presentation: 1 infant with liver failure and the other nearly unaffected. These findings suggest a need to look carefully for subclinical disease in the siblings of patients with NH by using sensitive tests such as those for ferritin and alpha-fetoprotein. They also suggest that affected infants may be missed when using routine clinical testing, which would lead to the apparent rate of recurrence, understating the actual recurrence rate.

Alphafetoprotein and alphafetoprotein receptor expression in the normal human placenta at term

Alphafetoprotein (AFP) is detectable in maternal serum from around six weeks of gestation and is synthesised by the yolk sac and the fetal liver. The role of the placenta in the transport and possible synthesis of AFP is uncertain. The aim of this study was to investigate placental expression of AFP and the AFP receptor in uncomplicated pregnancies at term. Immunohistochemistry and Western blotting clearly demonstrated the presence of AFP in villous tissue at term. However, evidence of AFP mRNA expression or synthesis of AFP was not found following reverse transcription polymerase chain reaction of total RNA isolated from villous tissue and trophoblast cell cultures. The presence of a cell surface receptor for AFP in placental villous tissue, identified by immunohistochemistry and Western blotting, suggests a possible receptor-mediated mechanism for placental transport of AFP while the patterns of expression of AFP and its receptor may indicate a possible route by which AFP is transported across the placenta between the fetal and maternal circulations. These findings demonstrate that the placenta does not synthesise AFP at term and that the presence of AFP in the placenta is a reflection of transplacental transport of AFP possibly via a receptor-mediated mechanism.

High-dose immunoglobulin during pregnancy for recurrent neonatal haemochromatosis

BACKGROUND

Neonatal haemochromatosis is a rare disease of gestation that results in severe fetal liver injury. We hypothesised an alloimmune aetiology for the disorder on the basis of its high recurrence rate in sibships. In this study, we assessed the effectiveness in preventing or changing the severity of recurrent neonatal haemochromatosis of administering during pregnancy high-dose intravenous immunoglobulin (IVIG) derived from pooled serum of multiple donors.

METHODS

Women whose most recent pregnancy ended in documented neonatal haemochromatosis were treated with IVIG, 1 g/kg bodyweight, weekly from the 18th week until the end of gestation in their subsequent pregnancy. The outcomes of treated pregnancies were compared with those of randomly selected previous affected pregnancies for each woman, which were used as historical controls.

FINDINGS

15 women were treated through 16 pregnancies. All pregnancies progressed uneventfully and resulted in live babies with normal physical examinations and birthweights that were appropriate for gestational age. 12 babies had evidence of liver involvement with neonatal haemochromatosis: 11 had higher than normal concentrations of serum alpha-fetoprotein and ferritin or serum alpha-fetoprotein alone, including four with coagulopathy (international normalised ratio >1.5), and one had coagulopathy alone. All babies survived with medical or no treatment and were healthy at follow-up within the past 6 months. In analysis on a per-mother basis comparing outcomes of treated gestations with those of randomly selected previous affected gestations, gestational IVIG therapy was associated with better infant survival (15 good outcomes vs two in previous pregnancies; p=0.0009).

INTERPRETATION

Treatment with high-dose IVIG during gestation appears to have modified recurrent neonatal haemochromatosis so that it was not lethal to the fetus or neonate. These results further support an alloimmune mechanism for recurrent neonatal haemochromatosis.

Congenital deficiency of alpha feto-protein

Alpha-fetoprotein (AFP) is the main fetus serum glycoprotein with a very low concentration in the adult. AFP deficiency is a rare phenomenon. We studied two families with congenital AFP deficiency and searched for mutations in the AFP gene. We identified one mutation of 2 base deletion in exon 8, in both families, that leads to the congenital deficiency of AFP. The mutation nt930-931delCT (T294fs25X) creates a frameshift after codon 294 that leads to a stop codon after 24 amino acids, thus truncating the normal length of AFP of 609 amino acids. All the affected children were found to be homozygous for the mutation as was one of the fathers. The affected individuals were asymptomatic and presented normal development. This first identification of a mutation in the AFP gene demonstrates for the first time that deficiency of AFP is compatible with human normal fetal development and further reproduction in males.

Biological roles of alpha-fetoprotein during pregnancy and perinatal development

The use of alpha-fetoprotein (AFP) as a serum marker in cancer actually predates its employment in the detection of congenital defects; however, the latter use of AFP as a fetal defect marker has propelled its clinical utilization. Although the serum-marker capacity of AFP has long been exploited, less is known of the biological activities of this oncofetal protein during fetal and perinatal development. In the present review, the biological activities of AFP are discussed in light of this glycoprotein's presence in various biological fluid compartments: embryonic and fetal tissues, serum, urine, and reproductive fluids. After a review of the histochemical detection of AFP in various cells and tissues during development, AFP concentrations within various biological fluids were discussed in the context of gestational age and anatomic location. Discussion follows concerning the relationships and roles of AFP in developmental events such as erthyropoiesis, histogenesis/organogenesis, and ligand binding and in developmental disorders such as hypothyroidism, folate deficiencies, and acquired immunodeficiency disorder (AIDS). Based on its association with so many types of birth defects, malformations, and congenital anomalies, AFP can be viewed as a molecular "troubleshooter" until signal transduction pathways are established during pregnancy and prenatal development. The review concludes with a discussion of the place of AFP in the rapidly expanding field of proteomics.

Levels of alpha-fetoprotein during pregnancy and early infancy in normal and disease states

Alpha-fetoprotein (AFP) was 1 of the first serum protein markers to serve in the dual capacities of tumor marker and fetal defect marker, ie, an oncofetal protein, in the clinical laboratory. Although the serum-marker capacity of AFP has long been used, less is known of the fluid compartments of this oncofetal protein during fetal and perinatal development. In this review, the biologic activities of AFP are discussed in light of its presence in the various biologic fluid compartments: fetal serum, amniotic fluid, cord blood, urine, and maternal serum. AFP concentrations within the biologic fluids are considered in the context of gestational age, sex, body weight, and anatomic location. Discussion follows concerning the relationships and roles of AFP in various developmental disorders such as hypothyroidism, folate deficiencies, autoimmune disorders, acquired immunodeficiency disorder (AIDS), congenital heart defects, cystic fibrosis, preeclampsia/hypertension, and platelet aggregation disorders. Based on its presence in so many types of birth defects, malformations, and congenital anomalies, AFP can be seen to serve as a form of molecular "duct tape" during pregnancy and postnatal development.

Neonatal hemochromatosis

Neonatal hemochromatosis is a rare gestational condition in which iron accumulates in the fetal tissues in a distribution like that seen in hereditary hemochromatosis. Extensive liver damage is the dominant clinical feature, with late fetal loss or early neonatal death. NH recurs within sibships at a rate higher than that predicted for simple Mendelian autosomal-recessive inheritance, possibly suggesting the role of a maternal factor. Immunomodulation during pregnancy at risk appears to lessen the severity of disease.

Congenital deficiency of alpha-fetoprotein and associated chromosomal abnormality in the placenta

In this study we describe two patients with congenital absence of alpha-fetoprotein (AFP). The pathological examination results, including an immunohistochemical stain, which define qualitatively the levels of AFP detected by the biochemical studies and the comparative genomic hybridization (CGH) are enclosed. A description of the suggested functions of AFP and the means of its production are set forth. An explanation is suggested for the lack of symptoms in a newborn with undetectable levels of AFP and the mechanism by which this condition might occur.

Relationship among maternal serum endocrinology, placental karyotype, and intervillous circulation in early pregnancy failure

OBJECTIVE

To evaluate the relationship among maternal serum endocrinology, placental karyotype, and intervillous blood flow in missed miscarriage.

DESIGN

Cross-sectional study of maternal serum, transvaginal ultrasound/Doppler, and placental cytogenetic and immunohistochemical investigations.

SETTING

Tertiary care academic hospital.

PATIENT(S)

One hundred fifty-two women with missed miscarriage between 7 and 13 weeks of gestation.

INTERVENTION(S)

Ultrasound features, placental intervillous circulation findings on color Doppler imaging, and maternal serum level of alpha-fetoprotein (AFP), beta-hCG, E(2), P, and inhibin A were compared retrospectively with placenta karyotype and hCG immunochemistry.

MAIN OUTCOME MEASURES

Data were analyzed according to karyotype results, presence or absence of an intervillous circulation, and delay between fetal demise and evacuation.

RESULT(S)

The presence of intervillous blood flow and serum concentrations of the different hormones were independent of placental karyotype. Serum beta-hCG and P were significantly higher in cases with intervillous blood flow. No difference in immunostaining for beta-hCG was found between placental tissues from normal pregnancies and missed miscarriages, but significantly higher villous beta-hCG content was found on Western blotting in miscarriage with a recent fetal demise.

CONCLUSION(S)

The excessive entry of maternal blood inside the placenta in the early stage of most miscarriages is unrelated to conceptus karyotype, and hCG features may reflect a temporary attempt of the trophoblast to stabilize after the initial oxidative insult.

Human alpha-fetoprotein binds to primary macrophages

We have previously reported that alpha-fetoprotein (AFP) inhibits infection of human monocyte-derived macrophages (MDM) by R5-HIV-1 strains and that a peptide mimicking the clade B HIV-1 gp120 consensus V3 domain (V3Cs) binds to CCR5. We demonstrate here that AFP binds high- and low-affinity binding sites of MDM, characterized, respectively, by 5.15 and 100nM K(d) values. Heat denaturation or neuraminidase treatment of AFP inhibits this binding, suggesting the involvement of protein-protein and lectin-carbohydrate interactions. Moreover, AFP displaces V3Cs binding to MDM. In addition, MIP-1beta, the most specific CCR5 ligand, displaces AFP binding to MDM (IC(50)=4.3nM). Finally, we demonstrate that AFP binds to a ligand of HIV-gp120 V3Cs domain, CCR5, expressed by MDM and by HeLa cells expressing CCR5. Such binding is not observed in the presence of HeLa cells lacking CCR5. The present results provide strong evidence that AFP directly binds to CCR5 expressed by human primary macrophages and by transfected CCR5+ HeLa cells.

Lens culinaris agglutinin-reactive alpha-fetoprotein, an alternative variant to alpha-fetoprotein in prenatal screening for Down's syndrome

BACKGROUND

Three serum tests, alpha-fetoprotein (AFP), human chorionic gonadotrophin and unconjugated oestriol, are now widely used for screening for Down's syndrome. Lens culinaris agglutinin-reactive alpha-fetoprotein (AFP-L3) is a variant of alpha-fetoprotein with alpha1-->6 fucose appended to the reducing terminal N-acetylglucosamine. It is the most prominent AFP detected in the serum of patients with hepatocellular carcinoma.

METHODS

We investigated microheterogeneities of the carbohydrate chain on AFP in fetal liver tissues, amniotic fluids and maternal sera obtained from pregnancies with Down's syndrome using lectin affinity electrophoresis with four lectins. The percentages of AFP-L3 in maternal sera from 22 Down's syndrome and 227 unaffected pregnancies were determined.

RESULTS

Unlike the case with AFP concentration, the percentage of AFP-L3 in maternal serum and amniotic fluid was similar, and apparently not influenced by membrane permeability. Knowing the percentage of AFP-L3 in maternal serum was effective for discriminating between Down's syndrome-affected pregnancies and unaffected pregnancies. The percentage of AFP-L3 in maternal serum identified 55% of Down's syndrome cases with a 5% false-positive rate.

CONCLUSIONS

AFP-L3 should be an effective replacement for AFP in prenatal Down's syndrome screening.

Pregnancy outcomes and community health: the POUCH study of preterm delivery

In light of the social/ethnic disparity in preterm delivery (PTD) rates, the Pregnancy Outcomes and Community Health (POUCH) Study takes a broad view of the determinants of PTD by attempting to link underlying biological and psychosocial factors. The relationships between placental pathology, maternal biomarkers, and antecedent psychosocial factors are evaluated in three hypothesised pathways of PTD - one characterised primarily by infection, one by maternal vascular disease, and one by premature elevations in corticotropin releasing hormone in the absence of histological evidence of placental pathology. Within each pathway, an emphasis is placed on understanding the roles of stress and of maternal serum alpha-fetoprotein, an early biomarker associated with PTD. The POUCH Study enrolls pregnant women from five Michigan communities. Information about these women and their environments is gathered through detailed interviews and collection of biological samples including hair, urine, saliva, blood, vaginal fluid, and vaginal smear at 15-26 weeks of gestation. We have chosen to focus on the second trimester--a time when pathological processes may have evolved to a detectable stage, but generally before the onset of biological changes that accompany labour. This focus is consistent with the long-range goal of early detection/intervention and prevention of PTD.

Alpha-fetoprotein structure and function: relevance to isoforms, epitopes, and conformational variants

Mammalian alpha-fetoprotein (AFP) is classified as a member of the albuminoid gene superfamily consisting of albumin, AFP, vitamin D (Gc) protein, and alpha-albumin. Molecular variants of AFP have long been reported in the biomedical literature. Early studies identified isoelectric pH isoforms and lectin-binding variants of AFP, which differed in their physicochemical properties, but not in amino acid composition. Genetic variants of AFP, differing in mRNA kilobase length, were later extensively described in rodent models during fetal/perinatal stages, carcinogenesis, and organ regeneration. With the advent of monoclonal antibodies in the early 1980s, multiple antigenic epitopes on native AFP were detected and categorized, culminating in the identification of six to seven major epitopes. During this period, various AFP-binding proteins and receptors were reported to inhibit certain AFP immunoreactions. Concomittantly, human and rodent AFP were cloned and the amino acid sequences of the translated proteins were divulged. Once the amino acid composition of the AFP molecule was known, enzymatic fragments could be identified and synthetic peptide segments synthesized. Following discovery of the molten globule form in 1981, the existence of transitory, intermediate forms of AFP were acknowledged and their physiological significance was realized. In the present review, the various isoforms and variants of AFP are discussed in light of their potential biological relevance.

Diagnostic and prognostic tumor markers in the gastrointestinal tract

The gastrointestinal tract is the most common site of malignancies of any anatomic system in the body. An early detection of primary tumors of the bowel, pancreas, liver, stomach, and esophagus is often difficult in asymptomatic patients and for this reason these tumors are often detected at a relatively advanced stage, when symptoms lead to a diagnostic evaluation. Furthermore, gastrointestinal tract tumors have an extremely variable prognosis; thus, the identification of new prognostic parameters may be useful for selecting patients to more tailored therapies. In this work, the main molecular, genetic, tissular, and circulating tumor markers proposed for diagnosis and prognosis of gastrointestinal malignancies are reviewed and discussed.

Pediatric germ cell tumors

Malignant germ cell tumors are relatively uncommon, accounting for approximately 3% of all childhood malignancies. Occurring with an incidence of approximately 4 per million among children less than 15 years of age, they account for approximately 225 new cases per year in the United States. Germ cell tumors occur in both gonadal and extragonadal sites, with extragonadal and testicular tumors predominating in children less than 3 years of age and with the gonads being the main location of tumors during and after puberty. They occur more frequently in girls than boys. Germ cell tumors are interesting for several reasons: (1) abnormal migration of primordial germ cells account for many of the childhood germ cell tumors; (2) markers exist to allow evaluation of the extent of resection and the development of recurrence for many of the tumors; and (3) the introduction of platinum-based chemotherapy has markedly improved the survival rate for germ cell tumors, as well as the salvage rate for recurrent or metastatic disease.

Transport of proteins across the human placenta

PROBLEM

The transport of various proteins across the human placenta was investigated by comparing maternal and fetal concentrations of tetanus antigen (TT-AG), anti-tetanus (TT)-immunoglobulin G (IgG) (following maternal vaccination), IgA, human chorionic gonadotropin (hCG), human placental lactogen (hPL), and alpha-fetoprotein (AFP) at term.

METHOD OF STUDY

The concentrations of the six proteins were determined using enzyme-linked immunosorbent assay in serum of maternal venous and umbilical (fetal) vein samples obtained at delivery from uncomplicated term pregnancies (n = 16).

RESULTS

The ratios (mean +/- standard deviation) of fetal (umbilical) to maternal level were 1.41 +/- 0.33 (anti-TT-IgG), 0.91 +/- 0.37 (TT-AG), 0.002 +/- 0.001 (IgA), 0.003 +/- 0.001 (hCG), and 0.008 +/- 0.004 (hPL), while the maternal:fetal concentration ratio of AFP was 0.002 +/- 0.002. IgA, hCG, hPL, and AFP showed a close correlation between maternal and fetal levels varying between r2 = 0.47 to 0.73 (P < 0.004-0.0001). Because AFP is produced by the fetus while IgA originates in the mother, the appearance of small amounts of these two proteins in the maternal or fetal compartment, respectively, suggests a slow rate of diffusion following a high concentration gradient. The detection of hCG and hPL in fetal serum is also interpreted as diffusion from the maternal into the fetal blood. Anti-TT-IgG has a significantly higher concentration in the fetal as compared with the maternal serum, which is in line with the well-documented active transfer of IgG. Fetal TT-antigen levels were similar to maternal concentrations, showing a close correlation (r2 = 0.74, P < 0.0001) between the two proteins.

CONCLUSIONS

The correlation between maternal and fetal concentrations of various proteins like IgA (150,000 Da), hCG (42,000 Da), and hPL (21,000 Da) suggests passive diffusion of these macromolecules across the placenta from the maternal to the fetal side, albeit at a slow rate. A similar process is postulated for AFP (70,000 Da) diffusing in the opposite direction from the fetus to the mother. There was no significant difference between the transplacental fetomaternal gradient of IgA and hCG and the maternal-fetal gradient of AFP. In view of the substantially larger volume of circulating maternal as compared with fetal blood, a significantly higher rate of crossing of AFP as compared with the other proteins must be assumed. It is uncertain whether a difference in the rate of transplacental transfer in the two directions or an additional source of AFP production in the maternal compartment explains the high maternal level. Anti-TT-IgG concentration is significantly higher in fetal than in maternal serum suggesting active transfer from the mother to the fetus. Furthermore, there is considerable transfer of TT-AG and a close correlation of fetal:maternal ratios of anti-TT-IgG (150,000 Da) and TT-AG (150,000 Da) could be an indication for a specific transfer of the antigen antibody complex.

Long-term outcome for infants and children with sacrococcygeal teratoma: a report from the Childrens Cancer Group

BACKGROUND/PURPOSE

Sacrococcygeal teratomas (SCT) are a relatively uncommon tumor affecting neonates, infants, and children. This study was designed to determine the effect of therapy on the long-term outcome of neonates and children with sacrococcygeal teratomas (SCT).

METHODS

The authors conducted a retrospective review of children with SCT treated at 15 Childrens Cancer Group institutions from 1972 to 1994.

RESULTS

One hundred twenty-six children presented with SCT diagnosed prenatally (n = 32), at birth (n = 79), or later in infancy (n = 15). For neonates, complete resection was performed except in two babies with lethal associated defects. All others (n = 15) underwent resection at the age of diagnosis. Six had a sacral mass identified at birth but had delayed surgery (1.5 to 11 months) and of these, two were malignant. Resection was via sacral (n = 96) or abdominosacral (n = 28) approach. Histology showed mature teratoma (MT, 69%), immature teratoma (IT, 20%), or endodermal sinus tumor (EST, 11%) at presentation. Seven neonates (5.6%) died of perioperative complications, whereas the remaining 117 were available for long-term follow-up. Between 6 and 34 months postresection, recurrent disease developed in 9 of 80 MT patients (11%) followed-up for a mean of 5 years. Recurrent disease was MT (n = 2) and EST (n = 7). The recurrent EST patients were treated with adjuvant chemotherapy. Six are alive with mean follow-up of 114 months, whereas one with metastatic disease was lost to follow-up. Recurrence (MT) developed in only 1 of 24 IT patients, and all are alive and well at mean follow-up of 39 months. Patients presenting with EST (n = 13) underwent excision, with two dying from non-EST causes. Six EST patients received no chemotherapy, with two of the six (33%) experiencing recurrence within 11 months and both disease free after salvage chemotherapy. The remaining five EST patients received adjuvant chemotherapy; four are alive and one died of metastatic disease. Of the 18 EST patients followed-up after resection (presentation, 11, recurrent teratoma, 7), 16 (89%) are free of disease with a mean follow-up of 91 months.

CONCLUSIONS

(1) Benign teratomas have a significant recurrence rate mandating close follow-up for more than 3 years. (2) Surgical resection alone is adequate therapy for nonmetastatic malignant tumors. (3) Survival for malignant lesions with metastases is excellent with modern chemotherapy.

Maternal serum screening for fetal genetic disorders

Maternal serum analyte screening is an integral component of contemporary antenatal care. Based on elevated MSAFP levels, 85% to 90% of NTDs (e.g., anencephaly or spina bifida) can be detected. Using a combination of serum analytes (e.g., MSAFP, hCG, UE3) 55% to 60% of fetal Down's syndrome can be detected. Future strategies for Down's syndrome screening may include the use of new markers such as dimeric inhibin-A and urinary beta-core fragment of hCG, as well as first-trimester screening, particularly with PAPP-A and free beta-hCG.

Maternal serum testing for alpha-fetoprotein and human chorionic gonadotropin in high-risk pregnancies

To evaluate the variations and potential clinical use of serial maternal alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) in pregnancies at risk of pregnancy-induced hypertension (PIH) and/or intrauterine growth retardation (IUGR), we investigated the relationship between placental sonographic findings, uterine artery Doppler measurements, and maternal serum AFP, hCG, and uric acid levels between 20 and 34 weeks of pregnancy. Maternal serum samples were collected from 41 singleton pregnancies with bilateral uterine notches and/or an increased uterine artery pulsatility index at 20-24 weeks. Maternal serum AFP, intact hCG and free alpha and beta subunits, and uric acid circulating levels were measured in all cases at 20-24 weeks and 25-28 weeks. Placental sonographic investigations comprised measurements of thickness and morphology. Twenty pregnancies had a normal outcome and 21 had an adverse outcome, including eight complicated by severe PIH with fetal IUGR, eight by isolated IUGR, three by mild PIH with normal fetal growth, and two by placental abruption. At the time of the first scan, the placental thickness and maternal serum levels of AFP, hCG, and uric acid were significantly increased in pregnancies with adverse outcomes, compared with those with a normal outcome. In subsequent maternal serum examinations, the incidence of elevated hormonal levels fell for AFP, intact hCG, and beta-hCG, whereas it increased for the uric acid level. No difference was found at any stage for the alpha-hCG level. Seven out of 11 pregnancies complicated by PIH presented with elevated MSAFP and MShCG and a large heterogeneous placenta at the first visit, whereas no pregnancy with a normal outcome presented with similar features. This study has shown a significant association between abnormal development of the utero-placental circulation, elevated MSAFP and MShCG at mid-gestation, and subsequent adverse pregnancy outcome. Serial measurements of MSAFP and MShCG do not provide extra information for the follow-up of these pregnancies.

Second-trimester maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated oestriol after early transvaginal multifetal pregnancy reduction

Maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), and unconjugated oestriol (UE3) are used as second-trimester screening markers for the detection of various fetal abnormalities. Previous studies have suggested that second-trimester MSAFP is consistently elevated after late first-trimester transabdominal multifetal pregnancy reduction (MFPR). The present study was undertaken to evaluate the levels of all three markers after early transvaginal MFPR. Maternal serum was examined for MSAFP, hCG, and UE3 at 16-18 weeks' gestation in 28 patients who underwent transvaginal MFPR at approximately 10 weeks' gestation. The mean interval between the reduction procedure and the screening test was 7.2 +/- 0.9 weeks. The mean MSAFP value in 24 patients carrying viable twins was 2.49 +/- 0.99 multiples of the median (MOM). Two patients had elevated MSAFP values: one in association with omphalocoele and the other in relation to an adverse pregnancy outcome. All but two patients had normal hCG values (mean 1.98 +/- 1.26 MOM). Two cases with elevated hCG were associated with an adverse pregnancy outcome. Unconjugated oestriol values were within the normal range in all patients (mean 1.69 +/- 0.61 MOM). These results suggest that early transvaginal MFPR, at approximately 10 weeks' gestation, does not appear to influence second-trimester MSAFP, hCG, and UE3 levels. The values of these markers may therefore be interpreted by using the same criteria as those for the general obstetric population.

Fetal hepatic alpha-fetoprotein mRNA expression in fetuses with trisomy 21 and 18 at 12-15 weeks gestation

In this study we examined alpha-fetoprotein (AFP) mRNA expression in fetal liver at 12-15 weeks of gestation in trisomy 21 (n = 13), trisomy 18 (n = 5) and control fetuses (n = 24). No significant difference was found in the steady-state level of fetal liver AFP mRNA levels in either of the two trisomy groups studied. These findings suggest that the decrease in maternal serum AFP concentration found in trisomic pregnancies is unlikely to be the consequence of impaired transcription of the AFP gene by the fetal liver.

The origin of alpha-fetoprotein in first-trimester anembryonic pregnancies

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.

Mechanisms of alphafetoprotein transfer in the perfused human placental cotyledon from uncomplicated pregnancy

We investigated the mechanisms of alphafetoprotein (AFP) transfer across the human placenta by correlating measurements of AFP transfer with cytochemical localization of AFP. Placental cotyledons were dually perfused in vitro with either the fetal or maternal perfusate containing umbilical cord plasma as a source of AFP. Steady state AFP clearance, corrected for release of endogenous AFP, was 0.973 +/- 0.292 microliter/min per gram in the fetal to maternal direction (n = 10), significantly higher (P < 0.02) than that in the maternal to fetal direction (n = 5; 0.022 +/- 0.013 microliter/min per gram). Clearance of a similarly sized protein, horseradish peroxidase was also asymmetric but clearance of the small tracer creatinine was not. Using a monoclonal antibody, we localized AFP to fibrinoid deposits in regions of villi with discontinuities of the syncytiotrophoblast, to cytotrophoblast cells in these deposits, to syncytiotrophoblast on some villi, and to trophoblast cells in the decidua. We conclude that AFP transfer in the placenta is asymmetric and that there are two available pathways for AFP transfer: (a) from the fetal circulation into the villous core and across fibrinoid deposits at discontinuities in the villous syncytiotrophoblast to enter the maternal circulation; and (b) AFP present in the decidua could enter vessels that traverse the basal plate.

Ultrastructure of the materno-embryonic interface in the first trimester of pregnancy

During early pregnancy, the absence of fully developed internal organs means that the embryo is dependent on highly differentiated adnexal structures such as the secondary yolk sac and free-floating amniotic membrane as well as the placental trophoblast. In this review, we describe and illustrate the ultrastructural characteristics of these different cellular barriers which separate maternal and embryonic tissues during the first trimester of pregnancy. Samples of chorionic plate, umbilical cord, secondary yolk sac and amniotic membrane have been obtained from intact gestational sacs of pregnancies between 6 and 11 weeks and examined at the ultrastructural level. Features indicating intense biosynthetic activity were found in the syncytiotrophoblast of the chorionic plate, the endoderm of the secondary yolk sac and mesenchymal cells of the amniotic membrane. Barriers in the form of a well-developed basal lamina were present between the trophoblast and mesenchyme of the chorionic plate and beneath the epithelium of the amniotic membrane and umbilical cord, but were incomplete between the mesenchymal tissues of the yolk sac and mesothelial and endodermal layers, and also around the capillaries of the chorionic plate. Basement membrane thickening and interactions with the underlying stroma were observed with increasing gestational age in connection with amniotic epithelial differentiation and development of basal foot processes. After 9 weeks, the yolk sac showed a marked degeneration of surface cells, accompanied by increased fibrosis of the mesenchyme. These findings are discussed with reference to the biological functions of the adnexal structures in the development of the growing embryo, and their possible role is assessed in the physiology of exchange during the first trimester of pregnancy.

Congenital deficiency of alpha-fetoprotein

Although alpha-fetoprotein may play a role in fetal immune function or in maintenance of osmotic pressure, its exact function is unknown. We report two infants documented to have congenital deficiency of alpha-fetoprotein. One infant had cord blood levels less than 0.5 ng/ml. The second infant had a neonatal level of 120 ng/ml, which is about 2% of the usual concentration for a term newborn. These infants document the existence of congenital deficiency of serum alpha-fetoprotein. Because it is homologous to albumin, congenital deficiency of alpha-fetoprotein may be analogous to analbuminemia, a benign genetic trait.

Mineral metabolism in the developing turkey embryo--I. The effects of developmental age and shell-less culture on trace element contents of selected tissues

1. Turkey embryos were incubated in ovo or in long-term shell-less culture (ex ovo) for 14, 18, 22 or 26 days. The embryos incubated ex ovo exhibited a progressive decline in the rate of growth and were hypocalcemic and hypoproteinemic compared to their in ovo counterparts from day 18 to day 26 of incubation. 2. The ratio of the concentrations of alpha-fetoprotein and albumin (AFP/A) in serum was determined for both groups of embryos. The AFP/A ratio may be useful as a biochemical index to stage avian embryonic development. Using this index it was concluded that ex ovo embryos exhibited a progressive developmental retardation compared to in ovo embryos. 3. Significant differences were observed in serum trace element concentrations for embryos incubated in ovo vs ex ovo. Most notably, serum copper concentration was significantly lower in ex ovo embryos on days 18 and 22 of incubation and significantly higher on day 26 of incubation compared to serum from embryos incubated in ovo. 4. Livers from embryos incubated ex ovo exhibited significant differences trace element levels compared to those incubated in ovo. By day 26 of incubation the concentration and total amount of zinc and iron were markedly elevated, whereas copper was greatly reduced in the livers of embryos incubated ex ovo compared to the corresponding in ovo levels. 5. Hearts from embryos incubated ex ovo contained less zinc and copper and more iron by day 26 of incubation than those from embryos incubated in ovo.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemistry and biology of alpha-fetoprotein

Alpha-Fetoprotein (AFP) is a product of specific fetal tissues and of neoplastic cells of hepatocyte or germ cell origin in adults. This protein belongs to a gene family that is phylogenetically most closely related to serum albumin. Its primary, secondary, and tertiary structural aspects appear similar to the three-domain concept proposed for the latter protein. The primary sequence of AFP departs most widely from serum albumin in the first 135 amino acid residues, with about 42% of the remaining 590 residues of the human proteins being identical. Some evidence exists that there are limited sequence differences in the AFP of a given animal species. AFP shows considerable charge heterogeneity that appears to relate mostly to its glycoid moiety. The proteins of some species such as the rat show more pronounced heterogeneities than that of humans. The variations in extent and type of glycosylations are evidenced by differences in the binding to various lectins. These interactions are being extensively explored in attempts to differentiate the sources of the protein produced by various normal and neoplastic cells and may provide valuable diagnostic methods. AFP, like serum albumin, shows relatively strong binding affinities for a variety of ligands. The most notable difference is the strong preferential binding of polyunsaturated fatty acids by AFP. This protein may play a role in transporting these substances to developing and to malignant cells. Various agents affect the synthesis of this protein both by specific fetal tissues and by neoplastic cells. Marked differences in the responses of cells, particularly those of neoplastic types, are indicative of variations in the genetic factors responsible for control of its synthesis. The subject of the genomic repression of the synthesis of AFP seen in fetal life upon maturation of the liver and the reoccurrence of synthesis upon malignant conversion of hepatocytes and of certain germ cells are of particular interest. The regulation of the closely related AFP and albumin genes is providing a powerful and attractive model to examine molecular events in the activation and inactivation of specific genes during development and in oncogenic processes. Extensive measurements of AFP during pregnancy and in the course of neoplasias, notably hepatoma, are being made to aid in following changes in such developments. Various specific physiological roles for this protein are also being proposed. One of these is its possible action in the regulation of immune processes.(ABSTRACT TRUNCATED AT 400 WORDS)

Massive congenital intracranial teratoma diagnosed in utero

The authors describe a case of congenital intracranial teratoma. The patient was diagnosed to be hydrocephalic at 29 weeks' gestation, and to have a huge intraventricular mass lesion at 34 weeks' gestation. Subsequently, the patient underwent subtotal resection of the mass, resulting in a significant decrease in the remarkably elevated alpha-fetoprotein in serum and cerebrospinal fluid. Histological analysis revealed a malignant teratoma, also with alpha-fetoprotein-positive elements in the immunohistochemical study.

Correlation of ultrasound and pathologic findings of placental anomalies in pregnancies with elevated maternal serum alpha-fetoprotein

Twenty pregnancies with elevated maternal serum alpha-fetoprotein (MSAFP), a normal fetus and unusual or abnormal placental/cord sonographic features are reported. These include: (A) gigantic enlargement with multiple sonolucent spaces of different size and shape (n = 2; Swiss cheese); (B) placental masses of variable echogenicity (n = 5); (C) cord masses with central echo-dense zone and peripheral hypoechoic areas (n = 2); (D) enlarged placentas with patchy decrease of echogenicity (n = 6; jelly-like); and (E) large sonolucent spaces with turbulent blood flow surrounded by normal placental tissue (n = 5; placental lakes). After delivery, these ultrasound features were compared with pathologic findings. Diffuse mesenchymal hyperplasia of the stem villi were found in the gigantic placentas (n = 2). The placental masses corresponded to chorioangiomas (n = 3), infarct (n = 1) or subamniotic hematoma (n = 1) and the cord masses to angiomyxomas (n = 2). The 'jelly-like' placentas were related to subchorial thrombosis (n = 2), massive fibrin deposition (n = 1) or hypertrophy with no obvious abnormalities (n = 3). Large subchorial thrombosis (n = 2), or no obvious abnormalities (n = 3) were observed in placentas with large lakes. These findings suggest that a large range of placental and cord anomalies are associated with elevated MSAFP and are potentially diagnosable by routine sonographic examination at the time of AFP screening.

Reduced fetal hepatic alpha-fetoprotein levels in Down's syndrome

In the majority of pregnancies involving a Down's syndrome (DS) fetus, the level of alpha-fetoprotein (AFP) measured in maternal serum and amniotic fluid is reduced to about 70 per cent of the level attained in normal pregnancies. Causes of this decrease may include the production of an altered AFP molecule with modified turnover or transport properties, or a reduction in the level of AFP synthesis. We examined hepatic AFP mRNA transcripts and compared AFP polypeptide isoforms in liver tissue samples obtained from a group of DS and normal abortuses. No differences was detected in the structure of the AFP mRNA transcript or in the charge or mass of AFP polypeptides in the two sample groups. However, the hepatic AFP level, expressed as microgram AFP/mg protein, was significantly lower in a group of 28 DS cases relative to a group of 47 normal controls (p = 0.04). This difference in hepatic AFP concentration did not appear to be the result of a general reduction in the level of total protein or total RNA production. The greatest difference between the AFP levels of the DS and normal groups was observed in the earliest samples examined (i.e., at 17-19 weeks of age) where the median AFP levels differed by about 20 per cent.