Distribution of alpha 1-fetoprotein in fetal plasma, allantoic fluid, amniotic fluid and maternal plasma of cows

High-Risk Pregnancy Is Associated With Increased Alpha-Fetoprotein Concentrations in the Amniotic Fluid and Foal Plasma

This study aimed to determine alpha-fetoprotein (AFP) concentrations in amniotic fluid, plasma of mares and respective foals: carrying normal pregnancies and delivering healthy foals (n = 20; Group 1); carrying apparently normal pregnancies and delivering sick foals (n = 15; Group 2); carrying high-risk pregnancies and delivering sick foals (n = 14; Group 3). High-risk pregnancy was defined by a history of premature udder development/lactation or increased of the combined thickness of the uterus and placenta, or vulvar discharge and/or mares' systemic illness. Sick foals were affected by neonatal encephalopathy, sepsis, prematurity/dysmaturity, or hypoxic-ischemic encephalopathy. Based on histological examination of the chorioallantois, AFP trend was analyzed in pregnancies with pathologic (PFM) and normal fetal membranes (NFM). Concentrations of AFP were measured using a commercially available immunoassay previously validated for horses. Mares' plasma AFP did not change during the last 15-20 days of pregnancy in the three groups, and there was no difference among them. Amniotic fluid AFP was higher in Group 3 (P = .014). Foals' plasma AFP concentration was higher from birth to 72hours in foals of Group 2 and 3 than in healthy ones, and foals of Group 3 had the highest value. The strong association (r = 0.84; P < .0001) between AFP in amniotic fluid and foals' plasma at birth is likely due to the presence of AFP in fetal urine. AFP was higher in pregnancy with PFM than with NFM in mare's plasma at admission (P = .031), amniotic fluid (P = .004), foal's plasma at birth (P = .002), at 24 (P = .005) and at 72 hours of life (P = .004). AFP is higher in pregnancy with histopathological lesions of the chorioallantois providing the evidence of the differences between pregnancy with a normal placental barrier and the more compromised ones. The increased AFP concentration in the amniotic fluid and plasma of high-risk foals suggests upregulation.

The concentrations of selected blood serum proteins in calves during the first three months of life

This study was aimed at the evaluation of changes in the concentrations of selected blood serum proteins in calves during the first three months of life, including precolostral, colostral, milk, transitional and solid feeding period. Nine clinically healthy calves were used in this study. The first blood sampling was performed before the colostrum intake (day 0) and then at 1, 2, 7, 14, 30, 60, and 90 days of age. Blood serum was analyzed for the concentrations of α1-fetoprotein, prealbumin, transferrin, and lactoferrin. The results showed significant changes in the serum concentrations of all the evaluated proteins in calves during the first three months of life (P< 0.01 andP< 0.001). At birth, the mean concentration of α1-fetoprotein was low and increased more than × 8 at one day after colostrum intake, then a gradual decrease was found up to day 30 of life. Similar tendency was observed in the concentrations of prealbumin and lactoferrin. While the concentrations of prealbumin increased approximately × 3.5 at one day after colostrum intake, the serum lactoferrin values showed approximately 1.5-fold increase. A subsequent gradual decrease from the 2ndday of life was found for both prealbumin and lactoferrin. In the concentrations of transferrin, a significant increase was observed on day 7 (P< 0.05). The highest values were found at the age of 14 and 30 days. These results suggest that concentrations of these proteins in calves are markedly altered during the postnatal period, which should be taken into consideration for their precise interpretation in young animals.

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.

Cellular transfer of macromolecules across the developing choroid plexus of Monodelphis domestica

Choroid plexus epithelial cells secrete cerebrospinal fluid (CSF) and transfer molecules from blood into CSF. Tight junctions between choroidal epithelial cells are functionally effective from early in development: the route of transfer is suggested to be transcellular. Routes of transfer for endogenous and exogenous plasma proteins and dextrans were studied in Monodelphis domestica (opossum). Pups at postnatal (P) days 1-65 and young adults were injected with biotinylated dextrans (3-70 kDa) and/or foetal protein fetuin. CSF, plasma and brain samples were collected from terminally anaesthetized animals. Choroid plexus cells containing plasma proteins were detected immunocytochemically. Numbers of plasma protein-positive epithelial cells increased to adult levels by P28, but their percentage of plexus cells declined. Numbers of cells positive for biotinylated probes increased with age, while their percentage remained constant. Colocalization studies showed specificity for individual proteins in some epithelial cells. Biotinylated probes and endogenous proteins colocalized in about 10% of cells in younger animals, increasing towards 100% by adulthood. Injections of markers into the ventricles demonstrated that protein is transferred only from blood into CSF, whereas dextrans pass in both directions. These results indicate that protein and lipid-insoluble markers are transferred by separate mechanisms present in choroid plexuses from the earliest stage of brain development, and transfer of proteins from plasma across choroid plexus epithelial cells contributes to the high protein concentration in CSF in the immature brain.

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.

Purification of canine alpha-fetoprotein and alpha- fetoprotein values in dogs

Canine alpha-fetoprotein (AFP) was purified by a two step method. Anti-dog AFP antiserum was produced by immunizing rabbits with canine fetal serum proteins that failed to bind to an anti-dog whole adult serum affinity column. Canine AFP was then purified from amniotic fluid using affinity chromatography with anti-dog AFP antiserum. The bound protein was then eluted and further purified by passage through an anti-dog whole adult serum column. The non-binding protein's purity and specificity was confirmed by immunoelectrophoresis, double-diffusion, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and cross-reactivity with anti-human AFP. The molecular weight of canine AFP was approximately 66,000 by SDS-PAGE. Normal adult dogs had serum AFP levels of 7-63 ng ml-1. Levels of AFP were not altered by pregnancy but did show a small peak 2 days following parturition. Newborn puppies had serum AFP levels of 14.08 +/- 5.94 mg ml-1 at birth. By 1 week of age, serum AFP had fallen to 0.766 +/- 0.758 mg ml-1. AFP values in newborn puppies are thus considerably higher than those previously reported in humans, pigs and cattle.

Fetuin as a marker of cortical plate cells in the fetal cow neocortex: a comparison of the distribution of fetuin, alpha 2HS-glycoprotein, alpha-fetoprotein and albumin during early development

Fetuin, alpha 2HS-glycoprotein (alpha 2HS), alpha-fetoprotein (AFP) and albumin have been shown to be present in some regions of the neocortex in two early stages of development of the cow brain using PAP immunocytochemistry. In the pre-cortical plate stage fibres of the primordial plexiform layer stained positively for fetuin. No staining was seen for albumin but plasma and cerebrospinal fluid (CSF) were positive for alpha 2HS and AFP. In the early cortical plate stage the strongest fetuin positive staining was seen in the earliest formed cells of the plate. alpha 2HS staining was much less intense but similar in distribution. The possible role of fetuin, or related glycoproteins, in cortical plate differentiation is discussed. Staining for AFP and for albumin was seen mainly in the ventricular zone and marginal zone fibres, and had a similar distribution and intensity for both proteins. Plasma and CSF stained for all four proteins. Tests showed some cross-reactivity between fetuin and anti-alpha 2HS and, to a much lesser extent, between antisera to AFP and albumin and antigens denatured by fixation.

alpha-Fetoprotein: relationship between maternal serum and amniotic fluid levels

Levels of alpha-fetoprotein were determined in 297 paired samples of maternal serum and amniotic fluid from patients with normal pregnancies at 16 to 17 completed weeks of gestation. Gestational ages were determined by menstrual history and ultrasonography, and the assays for alpha-fetoprotein were performed by a single reference laboratory. The results of the study failed to demonstrate any statistical relationship between the concentrations of alpha-fetoprotein in these two fluid compartments (r = 0.006). This finding was confirmed when the results at 16 and 17 weeks were analyzed individually. These findings indicate that amniotic fluid levels of alpha-fetoprotein cannot be predicted by those levels determined in maternal serum, and that simple diffusion is an inadequate explanation for the transfer of alpha-fetoprotein from amniotic fluid to maternal serum. The lack of correlation also emphasizes that the sensitivity and specificity of maternal serum alpha-fetoprotein screening for neural tube defects must continue to be based upon the detection rates in large population studies and the determination of "normal" values by reference laboratories.

High-performance liquid chromatography of proteins: purification of alpha-fetoprotein from fetal calf serum

High-performance liquid chromatography was utilized for the purification of bovine alpha-fetoprotein (BAFP) from fetal calf serum (FCS). An initial step in the purification involved absorption of charcoal delipidated FCS on Cibacron Blue F3GA gel. The Cibacron Blue pre-purified FCS was then chromatographed on a Polyanion SI weak anion-exchange column. The BAFP isolated had a purity of greater than 93% with an overall yield of 48% from FCS. The procedure was applicable for semi-preparative scale purification of BAFP.

Identification of fetuin in human and rat fetuses and in other species

The fetal protein, fetuin, has previously only been identified in species belonging to the order Artiodactyla. Samples of fetal, newborn and adult human (Homo sapiens) and rat (Rattus norvegicus) plasma and tissues have been studied using three techniques: (a) crossed immunoelectrophoresis of plasma against each of four different anti-fetuin antisera (two anti-cattle, one anti-pig and one anti-sheep); (b) the peroxidase-antiperoxidase technique applied to agarose gels containing plasma spots; (c) the indirect immunoperoxidase technique applied to human fetal tissue sections. In human fetal samples all three methods gave evidence for the presence of fetuin except late in gestation and in the newborn. Adult plasma was negative. In rat fetuses only plasma was tested, by methods (a) and (b). Positive reactions were obtained for both fetal and adult samples; the fetal samples cross-reacted with several of the anti-fetuins, adult samples reacted with only one. All the fetal and embryonal plasma samples tested with the peroxidase-antiperoxidase method were positive for fetuin except for the chicken. Thus fetuin appears to be distributed in at least five mammalian orders (Artiodactyla, Primates, Rodentia, Carnivora and Perissodactyla).