Identification of alpha-fetoprotein polymers. Artifacts of the isolation procedure

By combining polyacrylamide gel electrophoresis and radioimmunoassay, a method has been developed to detect polymeric forms of alpha-fetoprotein (AFP) during the isolation procedure. The method is capable of detecting AFP polymers in the presence of other serum proteins in serum samples that contain as little as 100 ng of AFP. Using this method, we have found that AFP polymers do not exist in cord serum; if encountered, we feel they should be considered to be artifacts of the isolation procedure AFP polymers appear in 7.5% polyacrylamide gel as multiple bands. We believe the multiple bands to be AFP polymers and not serum protein contaminants for the following reasons: (1) the electrophoretic pattern is very similar to that of serum albumin; (2) the polymers do exhibit AFP activity, although less than the monomeric form does; (3) the molecular weight of the dimer is exactly twice that of the monomer; (4) in the presence of sodium dodecyl sulfate and mercaptoethanol, the polymers move to the same position as do the monomers in polyacrylamide gel electrophoresis; (5) the polymers cannot be removed by repeated use of an immunoadsorbent affinity column designed to remove contaminant serum proteins.

A comparison of acid-elution techniques and alpha-fetoprotein levels for the detection of fetomaternal bleeding

Practical and reliable methods to identify and/or quantitate fetal blood are becoming more important in the modern practice of obstetrics. In this study, two commercially available acid-elution techniques were compared with plasma -alpha-fetoprotein (AFP) by simultaneously testing samples of fetal blood mixed with adult blood in fixed ratios. Thirty-one samples representing a range of amounts of fetomaternal hemorrhage, from 0.024 to 48 ml, were analyzed. The acid-elution techniques were equally effective in detecting fetomaternal hemorrhage greater than 15 ml, but the bmc Reagent set was the most accurate for detection of small numbers of fetal erythrocytes. The accuracy of AFP was greater than that of either acid-elution technique, but its clinical usefulness is limited by the necessity for a prehemorrhage sample.

The presence of 17 beta-hydroxysteroid dehydrogenase activity in preimplantation rat and mouse blastocysts

When Day 5 rat blastocysts and Day 4 and 5 mouse blastocysts were cultured in 53 microliters of medium containing 1340 or 2680 pg [3H]estradiol (E2), large amounts of [3H]estrone (E1) were detected in the medium at daily intervals for up to 5 days. This indicates the presence of 17 beta-hydroxysteroid dehydrogenase in the embryos. The activity was higher at a higher concentration of E2 and was also higher in mouse than in rat blastocysts. In the mouse, the activity was higher in Day 5 than Day 4 blastocysts during the first day in culture; then it decreased in Day 5 but increased in Day 4 blastocysts. The importance of E2 in embryonic development and implantation as suggested by others may be related to the activity of 17 beta-hydroxysteroid dehydrogenase.

The effect of intrauterine injection of concanavalin A on implantation in mice and rats

Concanavalin A (Con A) binding sites are present on the surface of blastocysts. When Con A was injected into one uterine horn of the mouse on Day 3 or 5 of pregnancy at 50 or 100 micrograms/horn, or given to the rat on Day 6 or 7 at 200 micrograms/horn, implantation and pregnancy was not affected when compared to the contralateral horn treated with vehicle alone. However, when the same amount of Con A was administered to the mouse on Day 4 or to the rat on Day 5, implantation was significantly decreased, all accompanied by the incidence of deciduomata. The deciduogenicity of Con A is dose-dependent. Also Con A did not affect the development of mouse embryos as a normal number of blastocysts was recovered up to the time of implantation. Thus the inhibition of implantation by Con A could be due to (a) the earlier occurrence of decidual cell response and its subsequent interference with implantation and (b) the involvement of specific sugar groups in implantation.

Serum alpha fetoprotein (AFP) levels in normal infants

Serum alpha-fetoprotein (AFP) levels were monitored in 32 normal babies consecutively from 2 to 3 days, 2 wk, and 2 and 4 months after birth. In addition, serum AFP concentration was also measured in 116 random specimens from infants with normal liver enzymes and 10 infants born immaturely. Results were combined to establish normal AFP levels for infants at various ages. Serum AFP disappeared rapidly after birth. We found that it was not until 8 months of age that the normal AFP level in infants approached adult level. The half-lives of AFP degradation were estimated to be 5.5 days between birth and 2 wk, 11 days between 2 wk to 2 months, and 33 days between 2 and 4 months of age. In contrast to earlier belief, we felt that some AFP synthesis still exists after birth; however, the rate of synthesis may also decrease with age.

Reserve bilirubin binding capacity assessed by difference spectroscopy: assay statistics and results on newborn sera

Bilirubin binding properties of newborn sera and assay parameters have been investigated using a difference spectroscopy procedure [9]. Reserve bilirubin binding capacity, serum bilirubin and the total bilirubin binding capacity can be determined using only 40 microliters of serum. The measured total binding capacities agreed with the theoretical binding capacities calculated from serum albumin concentrations assuming a 1 : 1 molar binding ratio of bilirubin to albumin; in 102 assays on newborn sera, the ratio of experimental to theoretical total binding capacity was 1.04. Bilirubin binding capacity measurements were linear over the range 0--600 mg/l. Day to day precision of binding capacity determinations on 6 albumin controls yielded coefficients of variation between 4.1 and 7.2%. Recovery for the reserve bilirubin binding capacity determinations was 99.6%. In a study of 22 newborns, reserve bilirubin binding capacities showed an inverse relationship with the changes in serum bilirubin concentrations. None of the newborns included in our study appeared to be in dange of bilirubin encephalopathy.

Concanavalin A binding capacity of preimplantation mouse embryos

Mouse embryos collected on Days 2 (2-cell) to 4 (early blastocyst) were treated with pronase to digest the zona pellucida and cultured at 37 degrees C for 3 h. These embryos and untreated Day-5 late blastocysts were exposed to [3H]Con A at 25, 50, 100 or 200 microgram/ml, 4 degrees C for 30 min, washed and counted for radioactivity. Other groups of embryos were incubated with [3H]Con A in the presence of 0.06 M-alpha-methyl-D-mannoside for the detection of non-specific binding. Scatchard plot analysis showed that the total number of Con A molecules bound/embryo increased with development, from 12 X 10(7) in 2-cell embryos to 19 X 10(7) in early blastocysts and to 150 X 10(7) in late blastocysts. The association constants decreased from 3 X 10(6) M-1 in 2-cell embryos to 0.83 X 10(6) M-1 in late blastocysts. The results suggest that the Con A binding sites (probably glycoproteins) on the embryo surface change quantitatively and qualitatively during preimplantation development.

Manual fluorometry of phenylalanine from blood specimens collected on filter paper: a modified procedure

In this manual fluorometric method, blood samples are used that have been impregnated on the filter paper, a convenient collection technique that is widely used to screen newborns for phenylketonuria. The modified procedure, based on the method of McCaman and Robins [J. Lab Clin. Med. 59, 885 (1962)], includes elution of phenylalanine from specimens on filter paper, removal of proteins by precipitation with trichloroacetic acid at 0 degrees C, and then reaction with ninhydrin-peptide reagent for color development. The standard curve is linear to at least 200 mg/L and the CV is 6.3% for a phenylalanine concentration of 27 mg/L. The modified procedure is suitable both for early screening for phenylketonuria and for monitoring blood phenylalanine of phenylketonurics during dietary therapy.

Manual fluorometry of phenylalanine from blood specimens collected on filter paper: a modified procedure

In this manual fluorometric method, blood samples are used that have been impregnated on the filter paper, a convenient collection technique that is widely used to screen newborns for phenylketonuria. The modified procedure, based on the method of McCaman and Robins [J. Lab Clin. Med. 59, 885 (1962)], includes elution of phenylalanine from specimens on filter paper, removal of proteins by precipitation with trichloroacetic acid at 0 degrees C, and then reaction with ninhydrin-peptide reagent for color development. The standard curve is linear to at least 200 mg/L and the CV is 6.3% for a phenylalanine concentration of 27 mg/L. The modified procedure is suitable both for early screening for phenylketonuria and for monitoring blood phenylalanine of phenylketonurics during dietary therapy.

Antifertility effects of an aromatase inhibitor, 1,4,6-androstatriene-3, 17-dione

1,4,6-Androstatriene-3,17-dione (ATD), previously reported by us to be an aromatase (estrogen synthetase) inhibitor, was found effective in inhibiting mating and ovulation in the rat. Mating did not occur for as long as treatment was continued (up to 13 days) in 68% of the rats. In the remainder, mating and ovulation were delayed for at least 4 days past the expected day of proestrus and for an average of 5.8 days. Five animals which had been treated for 6 days mated 2 days after treatment was discontinued and all were pregnant at autopsy on day 8 of pregnancy. In contrast, when treatment was continued after mating, implantation sites were absent when the animals were examined on day 8 of pregnancy, indicating ATD may also be effective postcoitally. ATD had no significant hormonal activity in bioassay but prevented the rise in ovarian estradiol secretion on the afternoon of proestrus. Estradiol benzoate counteracted the effect of ATD when administered concomitantly, so that mating occurred at the normal time in all eight rats and ovulation occurred in six of the eight rats. The above results suggest that the aromatase inhibitor, ATD, may act in vivo to inhibit fertility by inhibition of estrogen biosynthesis.

Serum creatine phosphokinase and pyruvate kinase in neuromuscular disorders and Duchenne dystrophy carriers

Serum levels of creatine phosphokinase (CPK) and pyruvic kinase (PK) were determined in 42 controls, 57 patients with various neuromuscular disorders, and 23 female relatives of Duchenne dystrophy patients. CPK and PK enzyme activities were increased in comparable numbers of muscle disease patients and female carriers; there was no advantage in the combined use of the two tests. We did not confirm earlier reports suggesting that determination of PK is more valuable than CPK in carrier detection.

Increase in concanavalin A binding sites in mouse blastocysts during implantation

The number of concanavalin A (Con A) binding sites were determined in mouse blastocysts before and during implantation. In intact pregnant mice (Day 1 = day of finding vaginal plug), the Con A binding sites per blastocyst were increased from 169 million on Day 4 morning to 1160 million on Day 5 morning when implantation was under way. In pregnant mice ovariectomized on Day 3 and treated daily with 1 mg progesterone, the Con A binding sites per blastocyst on Day 9 (inactive) were 363 million; if the mice had received an additional injection of estradiol 24 hours earlier to induce implantation, the Con A binding sites were increased to 1211 millions. Thus, a more than twofold increase in the Con A binding sites occurs in the mouse blastocyst during implantation.

Elevated plasma levels of carcinoembryonic antigen in cystic fibrosis

Elevated levels of plasma CEA were found in patients with cystic fibrosis. The elevations were well correlated with the Shwachman scores of the patients. Parallel changes of the levels of plasma CEA and clinical conditions of four patients were also observed in the follow-up studies. Close clinical examination indicated that the elevated plasma CEA of cystic fibrosis patients may be derived from sputum which is produced in abnormal amounts. This hypothesis is further supported by the very high content and the chromatographic profile of the CEA activity of sputum from patients with cystic fibrosis.