Fetal Serum Albumin Research Articles

A simple approach for fabrication of optical affinity-based bioanalytical microsystem on polymeric PEN foils.

Herein, we report a novel concept of low-cost flexible platform for fluorescence-based biosensor. The surface of polyethylene naphthalate (PEN) foil was exposed to KrF excimer laser through a photolitographic contact mask. Laser initiated surface modification resulted in micro-patterned areas with surface functional groups available for localized covalent immobilization of biotin. High affinity binding protein (albumin-binding domain (ABD) of protein G, Streptococcus G148) recognizing human serum albumin (HSA), genetically fused with streptavidin (SA-ABDwt), was immobilized on the micro-patterned surface through biotin-streptavidin coupling. Fluorescently labelled HSA analyte was detected in several blocking environments, in 1% bovine serum albumin (BSA) and 6% fetal serum albumin (FBS), respectively. We conclude that the presented novel concept enabled us to micropattern functional biosensing layers on the surface of PEN foil in a fast and easy way. It brings all necessary aspects for continuous roll-to-roll fabrication of low-cost optical bioanalytical devices.

An aqueous extract from toad skin prevents gelatinase activities derived from fetal serum albumin and serum-free culture medium of human breast carcinoma MDA-MB-231 cells.

An aqueous extract from toad skin, cinobufacini, has been known to possess anticancer ability. The present study examined effect of toad skin extract on activity of gelatinases including matrix metalloproteinases-2 and -9 which play an important role in invasion of carcinoma cells. Gelatinase activities derived from fetal serum albumin and culture medium of human breast carcinoma cell line MDA-MB-231 were significantly prevented in the presence of toad skin extract. The inhibitory activity was found in water-soluble fraction of the extract prepared by the Bligh & Dyer method but not in CHCl(3)-soluble lipid fraction. These results suggest that an aqueous extract from toad skin contains a water-soluble substance possessing a potent ability to prevent gelatinase activity. In conclusion, the water-soluble substance in toad skin extract cinobufacini may be able to regulate cancer cell migration accelerated by matrix metalloproteinases.

Detection of squalene in alpha-fetoprotein and fetal serum albumin from bovine.

Alpha-fetoprotein and fetal serum albumin have been simultaneously purified from fetal bovine serum by mild procedures utilizing ammonium sulfate, hydrophobic interaction, immobilized metal (nickel) affinity chromatography, and isoelectric focusing. The lipidic extract from each protein was analyzed by gas chromatography and the peak appearing just after the arachidonic acid was identified as squalene by gas chromatography-mass spectrometry. This isoprenoid was not detected formerly in these proteins from human, rat, bovine, and pig. Until recently, in the analysis of the fatty acid composition of the alpha-fetoprotein and serum albumin from mammals, a peak has been assigned in the last part of the chromatographic profile, after arachidonic acid, to docosahexaenoic acid. In the present work, it was found that the peak corresponds to squalene instead of docosahexaenoic acid. Furthermore, we conclude that bovine alpha-fetoprotein and fetal serum albumin carry squalene, but not docosahexaenoic acid. These results agree with others obtained analyzing the same proteins from chick embryo.

Digoxin transfer across the isolated placenta is influenced by maternal and fetal albumin concentrations.

The aim of this study was to evaluate the influence of different maternal and fetal albumin concentrations on the transplacental transfer and the placental tissue accumulation of digoxin. Digoxin passage across the isolated lobules of 15 human placentae was calculated from repeated fetal and maternal perfusate samples, and placental tissue digoxin concentrations were measured at the end of the experiments. Metildigoxin (Lanitop) was added to the maternal medium at a concentration of 5.70 +/- 0.73 ng mL-1, and maternal and fetal perfusate albumin (BSA) concentrations were kept equal either at a high concentration of 21 g L-1 (Group I; n = 5) or at a low concentration of 3 g L-1 (Group III; n = 5), or differed with a materno-fetal gradient of 21:3 g L-1 (Group II; n = 5). In the experiments with low maternal albumin concentrations (Group III), digoxin concentrations in the maternal circuit decreased to 3.56 ng mL-1, whereas digoxin concentrations in the fetal circuit reached 2.59 ng mL-1 over a 3-h period. With maternal BSA concentrations of 21 g L-1 (Group I and Group II), the decrease in digoxin concentration in the maternal circuit was lower (P < 0.05), and digoxin tissue concentrations at the end of the experiments were smaller (0.45 +/- 0.07 and 0.42 +/- 0.03 v. 0.82 +/- 0.32 ng mg-1 protein, Group I and Group II v. Group III respectively; P < 0.05). Comparing only those lobules with similar high concentrations of maternal protein, fetal BSA concentrations of 21 g L-1 resulted in a greater increase in digoxin concentrations in the fetal circuit (end-feto to initial-maternal digoxin concentrations of 0.44 +/- 0.08 v. 0.37 +/- 0.04 ng mg-1 protein (Group I v. Group II respectively), although this was not significant. The data suggest that maternal and fetal serum albumin concentrations may have an influence on transplacental digoxin transfer, and this should be considered when treating fetuses with cardiac disease transplacentally with glycosides.

Changes in serum albumin and α1‐acid glycoprotein concentrations during pregnancy: an analysis of fetal‐maternal pairs

The concentration of the two principal drug-binding proteins, albumin and alpha 1-acid glycoprotein, were measured in 44 paired fetal and maternal serum samples obtained at between 12 and 41 weeks gestation. Maternal serum albumin concentrations ranged between 25 and 35 g/l during this period. Fetal serum albumin was much lower in early gestation, ranging from 7.5 to 16 g/l at 12-15 weeks. With advancing age there was a linear increase so that at 30 weeks the fetal and the maternal serum albumin concentrations were in the same range and after 35 weeks the fetal concentrations exceeded the maternal by some 20%. Thus, the mean fetal/maternal serum concentration ratio of albumin increases from early pregnancy to term: 0.38 at 12-15 weeks; 0.66 at 16-25 weeks; 0.97 at 26-35 weeks; and 1.2 at greater than 35 weeks gestation. Maternal serum alpha 1-acid glycoprotein concentrations were scattered widely between 0.38 and 1.05 g/l. With the technique used fetal serum concentrations were hardly detectable before 16 weeks. Thereafter they increased at a constant rate, but never attained the maternal values. Near term a fetal/maternal serum concentration ratio of 0.37 was reached. These changes in protein concentrations may have important pharmacological implications.

The interaction of nogalamycin and analogs with DNA and other biopolymers

The interaction with calf thymus DNA of the anthracycline antibiotics, nogalamycin and its analogs, was studied by electronic absorption, circular dichroism (CD), thermal denaturation, solvent partition and pulse radiolysis techniques. The Scatchard, thermal denaturation (Δ T m ), difference circular dichroism (ΔCD) and solvent partition binding parameters gave the same order of relative binding on a given lot of DNA, but some parameters were DNA-lot-dependent. In general, molecules containing the sugar moiety nogalose at C-7 or those having the natural or ‘dis’ stereochemistry of nogalamycin at C-7 bound more strongly to DNA than did the molecules lacking nogalose or those with the opposite configuration at C-7 (‘con’ stereochemistry). This stereochemical-binding correlation differs from that found for adriamycin which has the ‘con’ stereochemistry, but which binds strongly to DNA. Scatchard binding parameters could not be obtained from the pulse radiolysis or solvent partition techniques because of solubility difficulties. The 7-con- O-alkylnogarol analogs differed in binding behavior from the other analogs. Although active tumor agents, they formed substantially weaker complexes with calf thymus DNA. They exhibited relatively large ΔCD spectra with human albumin (HA), in contrast to nogalamycin and some of the other analogs which formed strong DNA complexes but exhibited very small ΔCD spectra with HA. The HA and DNA binding results correlate with published data which show that 7-con- O-methylnogarol accumulates in the cytoplasm and its uptake is enhanced by fetal serum albumin, while daunomycin, an antitumor drug which binds strongly to DNA, accumulates in the nuclei and its uptake is unaffected by fetal serum albumin. Collectively, the data suggest that DNA may not be the primary target molecule for the antitumor activity of 7-con- O-methylnogarol or the other 7-con- O-alkylnogarol analogs. This conclusion is further supported by L1210 cell growth inhibition experiments with the drugs premixed with calf thymus DNA. The ΔCD, Δ T m and Scatchard binding parameters indicate that the nogalamycin molecules differ from adriamycin in their interaction with calf thymus DNA. Base pair specificity studies by CD indicate that the nogalamycin molecules interact differently with poly(dA-dT) · (dT-dA) as compared to poly(dG-dC) · (dC-dG) or calf thymus DNA.

Stimulatory effect of human alpha-fetoprotein and its molecular variants on in-vitro-induced lymphocyte blastogenesis.

Recent experiments suggested that alpha‐protein (AFP) may have immunoregulatory properties and play a role in protecting the fetus from rejection by the mother. The present study was performed to determine whether purified human AFP, its molecular variants separated on Lens culinaris agglutinin, and fetal serum albumin showed immunoregulatory activiiy on in vitro transformation of normal human lymphocytes by mitogens or by allogeneic cells. Human AFP and fetal serum albumin were purified from human whole fetuses by immunoabsorption, followed by acid elution. AFP variants (HLI, HL2, HL3, HL4) were separated by lectin affinity chromatography. The proteins were tested in lymphocyte cultures stimulated by concanavalin A, phytohaemagglutinin and pokeweed mitogen and in mixed lymphocyte cultures. Four batches of AFP and one batch of fetal albumin, in the concentration range of 0‐100 μg/ml and in one experiment up to 2 mg/ml, had a stimulatory effect on lymphocytes. One batch of human AFP showed inhibitory effect with low reproducibility. The variants had a stimulatory effect except for HL3, which was found to be slightly inhibitory in phytohaemagglutinin stimulated cultures when compared with cultures without AFP, but there was no significant difference when compared with cultures in which AFP was replaced by its dialysate. Thus, the results reported here are not consistent with the conclusion that human AFP has a significant immunosuppressive effect on man. Hypotheses about causes of discrepancies are analysed.

The presence of fatty acids in human alpha-fetoprotein.

alpha-Fetoprotein has been prepared from human fetal tissue by procedures utilizing DEAE-Sephadex, concanavalin A-Sepharose, and isoelectric focusing. A major and a minor component with isoelectric points of 4.7 and 5.3, respectively, have been isolated and are similar to those prepared under various conditions by other investigators. The 4.7 material contains 2.4 mol of fatty acids/mol of protein, whereas the minor component is fat-free. The relative amounts of fatty acid vary somewhat with different preparations. The ranges found in three isolates were as follows: palmitic acid (8 to 11%), stearic acid (2 to 5%), oleic acid (10 to 28%), linoleic acid (7 to 15%), arachidonic acid (12 to 39%), and 4,7,10,13,16,19-docosahexaenoic acid (16 to 42%). Human fetal serum albumin contained 0.7 mol of fatty acid/mol of protein, with arachidonic acid and the docosahexaenoic acid comprising only 11.4% of the total. Removal of fatty acids by treatment with charcoal converted alpha-fetoprotein into material with an isoelectric point of pH 5.3. Addition of arachidonic acid to the lipid-free protein restored it to protein with a pH 4.7 isoelectric point, typical of the major native component. The possible role of the fatty acids in alpha-fetoprotein on the inhibition of various lymphocyte functions is projected.

Characteristics of tryptophan binding in the serum of the newborn rat.

During the very first period of postnatal life, tryptophan is almost entirely free in the serum of rats. This situation is in sharp contrast with the well-known ability of serum albumin to bind the essential amino acid in the adult. Three main factors accounted for the relative lack of binding during the early postnatal life when compared to the adult: (1) the lower concentration of serum albumin, the binding protein; (2) the inhibition of binding by nonesterified fatty acids, which were at a high level in the serum of young rats until weaning, and (3) the decreased number of available binding sites for tryptophan on the defatted serum albimin, whereas the apparent association constant of tryptophan binding to serum albumin was similar in newborn and adult. Since immunological characterization of newborn and adult serum albumins did not reveal a specific fetal serum albumin, we suggest that discrete changes at the association site for tryptophan are sufficient to induce large alteration in the binding capacity of the protein. In contrast to the situation observed in adult rats, serotonin synthesis in the brain of newborn animals is therefore not dependent on the equilibrium between bound and free tryptophan in serum.

Maternal and fetal serum protein concentration in normal pregnancy and pregnancy complicated by proteinuric pre-eclampsia

The serum concentrations of 10 proteins have been studied in 18 normal mothers and babies and also 17 mothers with severe pre-eclampsia and their babies. Albumin was estimated by an AutoAnalyzer; IgG, by Mancini immunodiffusion; and thyroxine-binding prealbumin, alpha-1 antitrypsin, hemopexin, transferrin, haptoglobin, alpha-2 macroglobulin, beta lipoprotein, and beta-1 A-C (complement fraction), by Laurell immunoelectrophoresis. The results confirm the maternal concentrations of these proteins in normal pregnancy at term and show that in pre-eclampsia there is a fall in maternal albumin and immunoglobulin G (IgG) and an elevation in alpha-2 macroglobulin and beta lipoprotein. These changes are identical to those produced by the nephrotic syndrome, and it is suggested that this maternal dysproteinemia is a result of prolonged urinary protein loss. Babies born to mothers with pre-eclampsia had a significant elevation in alpha-1 antitrypsin, transferrin, and alpha-2 macroglobulin and a depression of thyroxine-binding prealbumin and IgG from normal values. Particularly notable was the unchanged concentration of fetal serum albumin, even in the presence of severe maternal hypoalbuminemia. These changes might be due to either (1) chronic maternal protein loss or (2) altered transplacental transference of amino acids in pre-eclampsia or (3) both. The possibility of neonatal hypogammaglobulinemia, dysmaturity, and neurological deficit occurring as a result of chronic intrauterine nutritional deficiency of essential nitrogen is discussed.