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Biomedical subjects

G J Mizejewski

Publications and source records attributed to G J Mizejewski.

At least 37 records · Page 2Linked to original sources
PubMed1995

The phylogeny of alpha-fetoprotein in vertebrates: survey of biochemical and physiological data.

The phylogeny of vertebrate alpha-fetoprotein (AFP) was surveyed in the phylum Chordata, including subphyla, agnatha, and Gnathostoma. A molecular taxonomic approach was undertaken based on biochemical, endocrinological, immunological, and physiological criteria previously documented for AFP. These published data were then discussed in light of their position and relationship in the albuminoid gene superfamily derived from GenBank. The phylogeny of the AFP molecule should prove useful for investigators seeking markers for animal models of human diseases, serological cross-reactivity between AFP molecular species, identification of larval or fetal protein homologs of AFP, and provide strategies for biochemical purification and physiological studies. The phylogeny of AFP in vertebrates was surveyed from the cyclostomata (lamphrey) to the mammals, including sharks, bony fishes, amphibians, reptiles, and birds. A trend was denoted, from lower to higher animal forms, in a size reduction and separation of AFP-like albumin molecular moieties from forms that resembled true albumin molecules. While the primitive lamphrey possesses a serum protein twice the size of mammalian albumin, the bony fishes, reptiles, and amphibians display two ALB-like molecules sharing amino acid sequence similarity to mammalian AFP. However, only one of the ALB-like molecules in the fish and amphibia is glycosylated. Although little has been published on reptilian AFP-like molecules, avian AFP has been investigated extensively following its detection and isolation for developmental studies involving immunology and neuroendocrinology. Finally, a plethora of knowledge exists in mammals following several decades of studies involving the isolation, purification, and characterization of AFP for use in physiological, immunological, and endocrinological research endeavors. In overview, a tendency or trend in down-sizing of an AFP-like albumin molecule and the separation of true albumin forms from a distinct fetal glycosylated form was observed. This seemed to occur in animal classes lacking a free-swimming larval form and possessing either highly differentiated extra-embryonic membranes or displaying a placenta intimately interfaced with the maternal tissues of the uterus.

Animals↗
PubMed1993

Purification of alpha-fetoprotein from human cord serum with demonstration of its antiestrogenic activity.

Alpha-fetoprotein (AFP) was purified from pooled human cord serum to determine whether it would be similar to purified mouse AFP in its ability to be transformed into an antiestrogen by incubation with estradiol (E2). Greater purity was attained with a three-step purification procedure of chromatofocusing, Blue-Sepharose chromatography and immunoaffinity chromatography than with a two-step procedure of polyacrylamide gel electrophoresis followed by Blue-Sepharose chromatography. Nevertheless, both procedures rendered AFP in a form that was transformable by E2 to an antiestrogen, although the product of the three-step procedure afforded more consistent biological activity. Removal of albumin from AFP was crucial for transformation of AFP to an antiestrogen. Thus, human AFP is similar to mouse AFP in being transformed to an antiestrogen upon incubation with E2, even though there is only 66% structural homology between the two proteins, and human AFP lacks the high-affinity binding site for E2 present in the mouse AFP molecule.

Animals↗
PubMed1993

An apparent dimerization motif in the third domain of alpha-fetoprotein: molecular mimicry of the steroid/thyroid nuclear receptor superfamily.

Alpha-fetoprotein (AFP) is a tumor-associated fetal marker, associated both with tumor growth and with birth defects. AFP, whose precise function is unknown, has been classified as belonging to a protein superfamily together with albumin and vitamin D-binding (Gc) protein. AFP has been shown to bind various ligands in vitro including fatty acids, estrogens, thyroid hormones and retinoic acids. The steroid/thyroid nuclear receptor superfamily of proteins has recently become a major focus of biomedical investigation regarding regulation of gene expression. These receptors are thought to bind to DNA-hormone response elements (HRE) that affect growth, development, differentiation, reproduction and homeostasis. The HREs are known to share DNA sequences with the various members of the nuclear receptor superfamily. In the present report, the possibility of a leucine-zipper dimerization (heptad) motif in the carboxy-terminal third domain of both rodent and human AFP is postulated. The presence of nine such hydrophobic repeats in the third domain of the AFP molecule mimics the heptad dimerization repeats found in the retinoic acid, thyroid, c-erbA and other members of the nuclear receptor superfamily. Computer analysis revealed that the most conservative matching occurred between AFP and the retinoic acid class of receptors. However, other superfamily members displayed 40-60% homology with 5 of 9 AFP heptads. These findings could provide a possible mechanism for explaining the growth-regulatory properties (both inhibition and enhancement) that have been ascribed to AFP in the last decade.

Amino Acid Sequence↗
PubMed1990

Inhibition of estrogen-dependent breast cancer growth by a reaction product of alpha-fetoprotein and estradiol.

Reaction of picomolar quantities of human or rodent alpha-fetoprotein (AFP) with nanomolar quantities of 17 beta-estradiol (E2) generates a product of unknown structure, designated AFP/E2, that inhibits estrogen-stimulated growth of mouse uterus. We describe herein the effect of rodent AFP/E2 on the in vivo growth of two estrogen-dependent breast cancers, the MCF-7 human breast cancer and the MTW9A rat mammary cancer. Both cancers were grown as xenografts under the kidney capsule of cyclosporine-immunosuppressed male BDF1 mice. In addition, the MTW9A tumor was grown as a homograft in syngeneic ovariectomized Wistar-Furth female rats. Estrogen support was provided by s.c. Silastic E2 implants. Injecting AFP/E2 that was generated by incubating 1.0 microgram of AFP with 0.5 microgram of E2 for 1 h at room temperature resulted in cessation of growth and, in most cases, regression of MCF-7 tumor xenografts. It also produced regression of MTW9A tumor homografts and significantly inhibited growth of MTW9A xenografts. Treatment with AFP alone or E2 alone did not inhibit growth of these tumors. The data suggest that AFP/E2 has a unique property which causes attenuation or shut-down of the biochemical reactions through which estrogen-dependent tumor growth is mediated.

Animals↗
PubMed1990

Effects of heavy metals on alpha-fetoprotein in maternal sera and amniotic fluid of pregnant mice.

This report describes the effects of low levels of copper, nickel and lead salts on the concentrations of alpha-fetoprotein (AFP) in the sera and amniotic fluid of pregnant Nylar mice. During the early and mid-gestation (9-17 days), pregnant mice were injected intraperitoneally twice with heavy-metal salt solutions and were autopsied two days following the second injection. Maternal sera and amniotic fluid (AF) were collected and AFP levels were quantified by radial immunodiffusion. Metal levels determined by X-ray fluorescence spectroscopy in individual samples confirmed the presence of trace metals in the fetus. Low doses of nickel and copper were associated with elevated AFP levels in amniotic fluid in 15-17 day pregnant animals, while maternal serum AFP levels mostly remained unchanged. Decreased concentrations of maternal serum AFP occurred with increased doses of copper and lead in contrast to elevated concentrations of AFP in amniotic fluid. Furthermore, there was an increase in fetal wastage when higher doses of copper and lead were administered. A reduction of secondary litter size (F1 generation) with low dosage levels of lead was also observed. These results imply that the fetal-maternal transfer of AFP may either be impaired or reflect increased leakage or decreased placental permeability in the presence of sublethal doses of copper and lead. These findings suggest that the parallel measurements of AFP concentrations in sera and amniotic fluid might be employed for assessment of embryo- and fetotoxicity when heavy metal intake is suspected during pregnancy.

Amniotic Fluid↗
PubMed1990

Binding of 16 alpha-[18F]fluoro-17 beta-estradiol to alphafetoprotein in Sprague-Dawley female rats affects blood levels.

To examine the relationship between blood levels of 16 alpha-[18F]fluoro-17 beta-estradiol(18F-ES) and serum alphafetoprotein (AFP) concentration, we undertook a study in which serum from various aged (20-33 days old) Sprague-Dawley female rats injected with 18F-ES was analyzed for both blood activity levels and AFP. There is a strong positive correlation between serum AFP concentration and 18F-ES blood levels (r = 0.914, P less than 0.001), suggesting that the binding of 18F-ES by AFP has a significant effect on blood activity levels. The AFP concentration and ultimately the AFP-18F-ES binding is dependent on the age and weight of the rat: younger, as well as low weight rats exhibited high AFP concentrations and consequently increased 18F-ES blood activity. The rats most suitable for comparative studying of labeled estrogens are 25-28 days of age and weigh a minimum of 50-55 g. Thus, the use of the immature rat model to compare labeled estrogens requires a careful consideration of possible interference from blood binding proteins (i.e. AFP), as well as potential receptor binding competition from endogenous estrogens produced during the estrous cycle. Comparable consideration of blood binding proteins (sex steroid binding protein, SBP) and endogenous estrogens must be made in human studies, as well.

Aging↗
PubMed1989

Alpha-fetoprotein can regulate growth in the uterus of the immature and adult ovariectomized mouse.

This is a report of development of (1) a 3-day immature mouse bioassay for alpha-fetoprotein (AFP) to increase the working range in uterine wet weights over-coming seasonality, and (2) a bioassay for AFP performed with ovariectomized adult mice to increase sensitivity. Mouse AFP was isolated from amniotic fluid and purified by polyacrylamide gel electrophoresis followed by Blue Sepharose chromatography. The uterine growth evoked by the injection of 1.0 microgram AFP together with excess molar oestradiol (0.5 microgram) over a 23-h period was compared in immature ovariectomized adult Nylar mice. The 3-day assay with immature mice was rendered usable in any season, with sensitivity comparable to the 1-day assay. Increased sensitivity, however, was demonstrated by utilization of AFP in a 1-day assay with the adult ovariectomized mouse.

Animals↗
PubMed1987

Combined use of alpha-fetoprotein and ultrasound in the prenatal diagnosis of arteriovenous fistula in the brain.

A case of arteriovenous fistula in the brain detected by the combined use of maternal serum alpha-fetoprotein (AFP) and ultrasound in the third trimester of pregnancy is described. The maternal serum AFP concentration at 34 weeks of gestation was 300 ng/mL (2.3 times the median). Stage II diagnostic ultrasonography at 37 weeks revealed a large midline cystic mass, contiguous to a normal-appearing lateral ventricle and surrounded by an abnormal heterogeneous zone of increased echogenicity. At birth, the cord blood AFP concentration was 2 SD above the mean. Subsequent histopathologic examination revealed a vein of Galen aneurysm and fistula in the brain.

Adult↗
PubMed1986

Studies of the intrinsic antiuterotropic activity of murine alpha-fetoprotein.

We previously reported that uterine growth in immature mice given estradiol (E2) is strongly curtailed by co-administration of trace amounts of alpha-fetoprotein (AFP). We used a semiquantitative bioassay for this antiuterotropic activity to evaluate AFP purification and storage methods. AFP was isolated from Nya:NYLAR mouse amniotic fluid (MAF) by polyacrylamide gel electrophoresis plus Blue Sepharose affinity chromatography (PAGE/BS), and by affinity chromatographies employing immobilized E2 and rabbit anti-AFP. E2 (0.5 micrograms) and purified AFP (0.1-50 micrograms) were incubated in 0.10 ml PBS for 1 hr at 22 degrees C and given intraperitoneally to female pups, and their uterine weights determined 23 hr later. The antiuterotrophic action increased with AFP dose up to 1 microgram (AFP/E2 molar ratio = 0.008) and declined at higher doses. Greatest inhibition by 1.0 microgram AFP occurred in 15-18 day old NYLAR pups weighing 5-8 g, but the magnitude (approximately 3 mg) was insufficient for generating a dose/response standard curve. We therefore express the activity of a preparation as the % inhibition that 1.0 microgram of its immunoreactive AFP content imposes on the uterine growth that 0.5 micrograms E2 would elicit. NYLAR AFP was more effective in NYLAR pups than in Swiss or Colony 22 pups suggesting strain specificity. High activity (54-88% inhibition) was found in all 9 batches of PAGE/BS AFP prepared over a 2 year period. The anti-AFP affinity product had similar activity, while the immobilized E2 product showed less. AFP in MAF was inactive but treatment with Norit or dextran/Norit generated partial activity. Acid/Norit treatment to remove fatty acids produced fully active AFP but in low yield. Purified AFP in storage retained activity for 1-2 weeks at 4 degrees C, up to 6 weeks at -20 degrees C, and up to 4 months in dithiothreitol-supplemented buffer. The activity is thus inhibited by other MAF constituents and decays by a temperature sensitive process that is slowed by an antioxidant.

Age Factors↗
PubMed1983

Induction of fetal wastage in pregnant mice passively immunized to murine alpha-fetoprotein.

Pregnant mice of various gestational ages were injected with purified rabbit IgG preparations of antibodies to mouse alpha-fetoprotein (AFP). Abortion of the fetuses was induced using 5-10 mg of total IgG, while 1.0 mg or less produced fetal wastage (death) depending on gestational age. While antibody-induced abortion occurred within 24 hrs, fetal death required 48-72 hrs for completion. Various non-IgG and control IgG solutions at comparable concentrations showed little or no effect in age-matched control mice. IgG preparations rendered devoid of specific anti-AFP antibodies were incapable of inducing fetal death following 3 cycles through immunoabsorbent chromatography. It was further observed that: 1) low concentrations of anti-AFP IgG appeared responsible for fetal death in early pregnancy and, 2) that antibodies, which did not readily bind to an affinity column, may possibly have caused fetal resorption. Finally, comparable studies in pregnant rats administered rabbit anti-rat AFP IgG did not exhibit abortion but only meager fetotoxic effects.

Abortion, Induced↗
PubMed1983

Estradiol-activated alpha-fetoprotein suppresses the uterotropic response to estrogens.

The binding of estrogen to alpha-fetoprotein (AFP) in the plasma cannot account for the impaired estrogen response seen in immature rodents because estradiol (E2) doses that far exceed the total body burden of AFP will stimulate only modest uterine growth. We investigated this phenomenon in immature female mice by determining their uterine weights 23 hr after intraperitoneal injection of estrogens or AFP or both. Administration of either 0.5 micrograms of E2 or 10 ng of moxestrol (MOX) approximately doubled the uterine weight. Giving 1 microgram of AFP 1 hr before injection of either estrogen did not alter that response. Combining the E2 and AFP just prior to injection resulted in decreased uterine growth (34% inhibition). Preincubating the estrogens with purified AFP (0.1-50 micrograms) did not affect the growth response to moxestrol but markedly decreased the response to E2. This was not due to sequestering of hormone because maximal reduction of the E2 response (ca. 65% inhibition) required only 1.0 microgram of AFP (AFP/E2 molar ratio, 1:130), and higher AFP doses inhibited less. About 40% of the growth elicited by injection of either 0.5 micrograms of E2 or 10 ng of MOX was inhibited when these doses were preceded by injection of the preincubated AFP/E2 mixture but not when preceded by either of the components. In each experiment, the mitotic index of luminal epithelium was affected to the same degree as uterine weight. AFP and E2 incubated for 1 hr thus produce a potent inhibitor of estrogen-stimulated mitotic activity and growth. This inhibitor might act upon estrogen-responsive cells at specific sites at which competition by an inactive component of AFP can block the process.

Animals↗
PubMed1983

Measurement of serum alpha-fetoprotein in early infancy: utilization of dried blood specimens.

Serum alpha-fetoprotein (AFP) concentrations were measured in dried blood spots and the biologic half-life of AFP was determined during the first month after parturition. AFP blood levels, in babies at all birthweight groups during the first wk, were partitioned according to birthweight and sex. A synthetic surge of serum AFP at postnatal day 3 was observed in babies of the low birthweight category (less than 6 lb 8 oz), whereas a concomitant surge could not be demonstrated in babies of medium, (6 lb 8 oz to 8 lb 8 oz), and high birthweight, (greater than 8 lb 8 oz), categories. All babies weighing less than 6 lb 8 oz, regardless of prematurity likewise displayed the synthetic surge. The sex of the infant appeared to have no influence on AFP serum concentrations. In a population of infants ranging in age from 1-30 days, the biologic apparent half-life of AFP was calculated as 5.7 days; however, the half-life of AFP was found to differ among the three groups of infants when subdivided by birthweight and was higher (7.7 days) in babies of low birthweight. Our determination of 2 S.D. cutoff values for AFP in the first wk of life should prompt further studies in which the relationship of AFP to newborn disorders should be more fully explored.

Birth Weight↗
PubMed1983

Modulation of tumor incidence by oncofetal products in a syngeneic hepatoma cell-spleen cell model.

An experimental model is described for analysis of cellular and molecular mechanisms involved in the modulation of tumorigenicity by syngeneic lymphoid cells and oncofetal products in vivo. The effect of mouse amniotic fluid (AF) and alpha-fetoprotein (AFP) from this fluid and from serum, free or bound to estrogens, upon the growth of a syngeneic hepatoma was examined in mice transferred with syngeneic spleen cells from hepatoma-bearing donors. Intraperitoneal transfer of spleen cells from hepatoma-bearing into normal syngeneic mice, either tended to stimulate or to inhibit tumor growth in the latter depending on the length of time elapsed between tumor-transplantation in the spleen-cell donor and their sacrifice for spleen excision. For example, only the spleen cells obtained on day 14 and 21 following tumor transplantation protected the recipients from tumor growth. When these protective cells were mixed with hepatoma cells from a low incidence line, and the mixture injected subcutaneously, tumor incidence increased (tumor-promotion effect) rather than the contrary. AF was immunosuppressive inasmuch as it amplified the tumor-promotion effect of the spleen cells. On the other hand, purified AFP from sera of hepatoma bearing mice abolished this tumor-promotion effect.

Amniotic Fluid↗
PubMed1982

Characteristics of the androgenization produced in mice by neonatal exposure to alpha-fetoprotein antibodies.

Neonatal male and female mice, ages 1-5 days, were injected intracranially with either anti-alpha-fetoprotein (AFP) IgG, steroids, or various control solutions. The mice were autopsied 60-70 days later and the spleen, thymus, liver and gonads were examined by light microscopy. The antibody to AFP produced a gonadal response which was sexual specific. Histological examination of the tissue sections from female mice treated with either anti-AFP IgG or steroids revealed the presence of polyfollicular ovaries lacking in corpora lutea formation. A comparable antibody-induced specific effect on the testes could not be demonstrated; however, steroidal administration induced aspermatogenesis and delayed maturation in parallel studies. In the anti-AFP IgG-treated groups, there appeared a gross neurological lesion which was termed external hydrocephaly. The physiologic responses in the female gonad were found independent of the presence of this anatomical brain lesion, whereas those in the male gonad were found causally related. The immunological specificity of the gonadal response was demonstrated by the use of IgG devoid of anti-AFP IgG and by various IgG control solutions. Thus, exposure to anti-AFP IgG during the critical period of sexual development in the brain appears to mimic steroidal androgenization of the female mouse.

Animals↗
PubMed1982

Commercial radioimmunoassay kit for measurement of alpha-fetoprotein adapted for use with dried blood specimens from newborns.

We adapted a commercial RIA kit to measure alpha-fetoprotein (AFP) in 0.785-microliters portions of 60-microliters spots of dried blood from newborns. We evaluated sample elution, temperature and time stability, between- and within-assay variability, sensitivity, and use of liquid vs dried specimens of blood. Also, we present normal AFP concentrations for healthy neonates during the first postnatal week. Our procedure permits measurement of AFP concentrations both in maternal liquid plasma and in spots of dried blood from the infant with the same RIA kit reagents and standards. The sensitivity, precision, stability, and simplicity of this procedure makes more practical the routine measurement of AFP in dried blood specimens from newborns than measurement in liquid plasma or serum. Blood-sample collection by heel stick suffices for this simple, efficient, inexpensive determination of AFP concentration in the newborn.

Blood Chemical Analysis↗