Showing papers on "Fetus published in 1981"
TL;DR: In mice, rabbits, and pigs, two basic types of cardiac myosin isoenzymes were found by electrophoresis of native molecules: a fast-migrating form with high Ca(2+)-dependent ATPase activity and a slow-migrated form with low activity.
356 citations
TL;DR: During obstetrical ultrasound examinations, 200 M-mode and 35 real-time two-dimensional echocardiographic studies were performed on 180 fetuses of high-risk pregnancies, and Paradoxic septal motion in 50 fetuses suggested relarive right ventricular volume loading.
Abstract: During obstetrical ultrasound examinations, 200 M-mode and 35 real-time two-dimensional echocardiographic studies were performed on 180 fetuses of high-risk pregnancies. Fetal gestational ages ranged from 18 to 41 weeks. M-mode "sweeps" demonstrating mitral- and septal-aortic fibrous continuity were obtained in 115 studies. Paradoxic septal motion in 50 fetuses suggested relarive right ventricular volume loading. Congenital cardiac malformations were accurately diagnosed in a 34-week fetus with pulmonary atresia and hypoplastic right ventricle and in a 28-week fetus with a univentricular heart. Congenital complete atrioventricular block was diagnosed in a 28-week fetus and atrial flutter with variable atrioventricular block was diagnosed in a 38-week fetus. The use of echocardiographic studies to evaluate cardiac structure and rhythm in utero assists in counseling prospective parents and in planning postnatal management for their offspring.
240 citations
TL;DR: Two fetuses with severe anaemia due to rhesus incompatibility each received two early blood transfusions by fetoscopy byfetoscopy, and one grossly hydropic fetus survived.
225 citations
TL;DR: An increasing body of evidence suggests that neuroendocrine mechanisms differentiate and function from early in fetal life in many mammals, whereas in others with slower neural development this maturation occurs in the perinatal period.
Abstract: The neural control of fetal pituitary hormone secretion and the conceptualization of the integration of neural, neurotransmitter, neuromodulatory, and humoral signals in the fetus is an emerging field of interest. At an early stage in the construct of the neurosecretory neuron, Berta and Ernst Scharrer (1, 1a) proposed that neurosecretion is a phylogenetically “old and fundamental attribute of neural elements.” Not only is neurosecretion a primitive regulatory system but an increasing body of evidence suggests that neuroendocrine mechanisms differentiate and function from early in fetal life in many mammals, whereas in others with slower neural development this maturation occurs in the perinatal period. Among the earliest studies are those of Jost (2), who observed that decapitation of the male rabbit fetus impaired fetal testicular function. Neurohormones are present in the fetal hypothalamus at the time of its initial differentiation from the primitive forebrain, and it is likely that even before full m...
219 citations
TL;DR: The mechanism for the increased plasma Ep associated with hyperinsulinemia in the fetus is unexplained but may be mediated by fetal hypoxia.
Abstract: The pathogenesis of the increased erythrocytosis and extramedullary erythropoiesis observed in infants of diabetic mothers (IDM) has been obscure. In the present studies, IDM were found to have elevated umbilical plasma erythropoietin (Ep) concentrations by radioimmunoassay. 22 of 61 IDM (36%) had levels above the range of 28 nonasphyxiated, appropriately grown normal infants. In 16 controls and 20 IDM, plasma Ep correlated directly with plasma insulin (P less than 0.001, r = 0.73). To investigate this relationship further, a chronic rhesus model was studied with continuous fetal hyperinsulinemia for 21 d in utero in the last third of pregnancy. In five experimental fetuses, plasma insulin levels averaged 4,210 microU/ml at delivery, whereas plasma Ep was above the range of six controls. In addition, the experimental fetuses had elevated reticulocyte counts in umbilical cord blood. The mechanism for the increased plasma Ep associated with hyperinsulinemia in the fetus is unexplained but may be mediated by fetal hypoxia.
218 citations
TL;DR: The normal structural and functional development of the pulmonary circulation has been studied in the pig, from fetal life to six months of age, with emphasis on the first 2 weeks, where a significant reduction in the amount of arterial muscle was associated with a reduction in pulmonary vascular resistance.
Abstract: The normal structural and functional development of the pulmonary circulation has been studied in the pig, from fetal life to six months of age, with emphasis on the first 2 weeks. Pulmonary and systemic arterial pressures were measured in 50 animals, in 21 of which pulmonary vascular resistance was determined. After post mortem arterial injection, lung structure was analysed using quantitative morphometric techniques. Changes in the pulmonary circulation consisted of three overlapping phases:
1 Dilatation and recruitment of small arteries within the acinar region, beginning during the first 5 min and associated with a reduction in pulmonary arterial pressure. These changes continued during the first 24 h, associated with a loss of arterial muscle.
2 Between 24 h and 2 weeks, a significant reduction in the amount of arterial muscle was associated with a reduction in pulmonary: systemic vascular resistance ratio from 0.58 to 0.18.
3 Functionally, the pulmonary circulation appeared mature at rest by 2 weeks but growth and remodelling of the pulmonary arteries continued until an adult pattern was reached by 6 months of age.
180 citations
TL;DR: It is postulated that inactivation of F to E in the hemochorial placenta and in the fetus itself protects the fetus against the growth-inhibiting effects of F, while production of F from E inThe membranes and uterine wall contributes to the maintenance of the fetal allograft.
175 citations
TL;DR: Single chorionic villi were obtained before elective abortion from pregnancies of 8-14 weeks' duration, and accurate globin gene analysis proved possible with the DNA obtained from these samples.
169 citations
TL;DR: Flow per unit of fetal weight was constant during pregnancy until 36 to 37 weeks, when a reduction occurred, and was maximal between 37 and 38 weeks, then decreased during the last 2 weeks of pregnancy.
159 citations
TL;DR: Until recently, the only question raised by the prenatal diagnosis of a fetal malformation was whether to abort the fetus, but other therapeutic alternatives are becoming available, such as changing the timing of delivery, changing the mode of Delivery, and even treatment before birth.
Abstract: THE HUMAN fetus has for centuries remained a medical recluse in an opaque womb. Now fetal anatomy, normal and abnormal, can be accurately delineated by ultrasonography, a noninvasive technique that appears safe for fetus and mother. Some fetal malformations with a known pattern of inheritance may be specifically sought. However, many are identified serendipitously during obstetric sonography, sometimes because the obstetric conditions that lead to sonography are associated with underlying fetal malformations. For example, oligohydramnios is associated with fetal urinary tract obstruction and polyhydramnios with fetal upper gastrointestinal (GI) tract obstruction. 1-4 Until recently, the only question raised by the prenatal diagnosis of a fetal malformation was whether to abort the fetus, but other therapeutic alternatives are becoming available, such as changing the timing of delivery, changing the mode of delivery, and even treatment before birth. Since perinatal management may be altered, prenatal diagnosis now assumes practical clinical importance. In
156 citations
TL;DR: In sheep, the liver to kidney switch of Ep production is initiated in utero during the last third of the gestation period, but is completed after birth, and this transition occurs gradually; the assumption of Ep producing capacity by the kidney is not preceded by an abrupt loss of hepatic Ep formation; and the switch is profoundly influenced by alterations in thyroid hormone and oxygen supply-demand levels.
Abstract: Although the liver is the major site of erythropoietin (Ep) production in the fetus, this function is assumed by kidneys in the adult. The mechanisms underlying the liver to kidney switch of Ep formation are not understood. We studied the natural progression of this transition in sheep by measuring Ep production in response to anemia in normal and bilaterally nephrectomized fetal and newborn sheep beginning at about 80 d gestation (normal gestation: 140 d). Removal of both kidneys before induction of anemia did not affect Ep formation up to about 120 d of gestation. A significant reduction (29%, P < 0.02) in Ep synthesis was first noted at about 130 d of gestation (initiation of switch). This level of nephrectomy-induced reduction of Ep formation persisted until about 15 d after birth. Thereafter, bilateral nephrectomy caused further significant decreases (P < 0.05) in Ep production, gradually resulting in near total absence of Ep production at about day 40 postpartum (completion of switch). Chronic administration of testosterone (12 mg/wk) or estradiole benzoate (1.5 mg/d, 5 d/wk) to the fetus/newborn beginning at 85-90 d of gestation enhanced or suppressed erythropoiesis, respectively, but failed to affect the time at which the liver to kidney switch was initiated and/or completed. By contrast, a significant delay (P < 0.001) in the onset, but not completion of the switch occurred in animals that were either thyroidectomized or rendered chronically anemic beginning in the second third of the gestation period. Administration of thyroxin (1.2 mg/d, 5 d/wk) to thyroidectomized fetus/newborns not only prevented the delay in the initiation of the switch, but also accelerated the rate at which the switch was completed. These results demonstrate that in sheep (a) the liver to kidney switch of Ep production is initiated in utero during the last third of the gestation period, but is completed after birth, (b) this transition occurs gradually; the assumption of Ep producing capacity by the kidney is not preceded by an abrupt loss of hepatic Ep formation; and (c) the switch is not affected by changes in sex hormone levels during the prenatal-postnatal growth periods, but is profoundly influenced by alterations in thyroid hormone and oxygen supply-demand levels.
TL;DR: The early second trimester is a critical period for human fetal lung growth and lung hypoplasia defined in terms of lung/body weight ratio was associated with low lung DNA content for gestation, even when corrected for body weight.
Abstract: Total DNA was estimated in the lungs of 80 fetuses and newborn infants varying in gestation from 14 weeks to term. In fetuses of appropriate weight for gestational age total lung DNA increased at a constant rate from about 35 mg at 17 weeks' gestation to 480 mg at term. The lungs of immature fetuses were heavier and contained more DNA relative to body weight than did those of mature infants. Small-for-dates infants had lower lung DNA levels for gestation than infants with weights appropriate for gestational age, but there was no difference when lung DNA was corrected for body weight. Lung hypoplasia defined in terms of lung/body weight ratio was associated with low lung DNA content for gestation, even when corrected for body weight. The total lung DNA at 34-40 weeks' gestation in infants with lung hypoplasia associated with fetal anuria or urinary outflow obstruction was equivalent to that seen in normal fetuses at 20-22 weeks' gestation. We conclude that the early second trimester is a critical period for human fetal lung growth.
TL;DR: The binding and mitogenic activity of EGF is described both in vitro and in vivo in several fetal mouse tissues, suggesting that EGF may play a part in fetal growth and development of specialized function.
Abstract: Epidermal growth factor (EGF) is a small polypeptide (6,045 molecular weight) well recognized as a mitogen affecting a variety of cell types (see refs 1–3 for reviews). Its mitogenic effect is mediated through specific high-affinity receptors on the plasma membrane, and after ligand binding, some (but not all) cells respond in a variety of ways which lead to either increased growth rate or differentiation. Although the initial description of EGF by Cohen4 demonstrated a maturational influence on eye-opening and tooth eruption in newborn mice, there has been little investigation of the effect of EGF on developing fetal tissues. Nexo et al.5 have provided evidence that EGF and its receptors are present in mouse embryos as early as day 13 of gestation, especially in the secondary palate where EGF may have a role in palate closure, and EGF receptors have also been described in the human placenta6 and in fetal rabbit lung7. Thus, the limited data available suggest that EGF may play a part in fetal growth and development of specialized function. Here, we describe the binding and mitogenic activity of EGF both in vitro and in vivo in several fetal mouse tissues.
TL;DR: Evidence is found that immunity to fetal antigens expressed on tumor cells is a participant in host-tumor interaction and a positive correlation with disease-free interval and survival was detected among patients who had high levels of the IgM class of antibody before and shortly after surgery for state II disease.
Abstract: Antibody directed against a cultured melanoma cell line known to express an oncofetal antigen was measured in sera obtained from patients with stage II melanomas. This study was undertaken to determine if an inhibiting or enhancing effect on tumor growth would be suggested by a positive or negative correlation of antibody levels with tumor recurrence or patient survival. A positive correlation with disease-free interval and survival was detected among patients who had high levels of the IgM class of antibody before and shortly after surgery for state II disease. The IgG class of antibody over the period measured did not correlate consistently with tumor recurrence. Absorption of the IgM antibody with fetal brain confirmed that the dominant detectable reactivity was directed to the oncofetal antigen. The relevance of these findings is related to that of other evidence indicating that immunity to fetal antigens expressed on tumor cells is a participant in host-tumor interaction.
TL;DR: A radioimmunoassay (RIA) has been developed to the species of lactogenic hormone (rPL) present in late pregnant rat placenta, revealing the presence of two possibly unrelated forms of rPL.
Abstract: A radioimmunoassay (RIA) has been developed to the species of lactogenic hormone (rPL) present in late pregnant rat placenta. Partially purified rPL calibrated against oPRL in the rat liver receptor assay (RRA) was used as standard. Hone of the PL's, PRL's, and RH's from other species cross-reacted in the RIA when tested at 1000 ng/ml. Rat serum PL levels remained stable in samples stored at -70C but not at -20C. In previous studies, using RRA, two peaks of rPL were found in rat serum, one at Day 11–13 and one at Day 20. By RIA, however, only the 20,000 dalton species of rPL present in late pregnant serum was immunoreactive. The RIA did not detect the larger, 40–50,000 dalton molecular species of rPL predominant in mid-pregnant serum, thus revealing the presence of two possibly unrelated forms of rPL. Serum rPL concentrations at Day 21 of pregnancy increased exponentially as the number of fetuses increased until a maximum of nine fetus.
TL;DR: It appears that the response of the Fetal kidney to hypoxemia depends on the degree of fetal maturation, and the ability of the fetal kidney to reabsorb free water is more developed in near-term fetuses.
Abstract: The effects of fetal hypoxemia on renal hemodynamics and renal function were studied in two groups of chronically catheterized young ( 130 days). Fetal hypoxemia produced, in both groups, a significantly decrease in renal blood flow (RBF) and a significant increase in the filtration fraction. However, the glomerular filtration rate (GFR) did not change significantly suggesting that the renal vasoconstriction associated with fetal hypoxemia was more important at the efferent than at the afferent arteriolar level. In the group of near-term fetuses, the decrease in RBF correlated closely with changes in plasma renin activity (PRA) (r = 0.77). No changes in PRA were observed during hypoxemia in the group of young fetuses. After hypoxemia, reactive hyperemia associated with a significant increase in urinary prostaglandin excretion (PGE and PGF2 alpha) was observed in near-term fetuses but not in young fetuses. It also was demonstrated that fetal hypoxemia produced a significant increase in fetal plasma concentrations of vasopressin associated with an antidiuresis in all but one near-term fetus and in 50% of the young fetuses, suggesting that the ability of the fetal kidney to reabsorb free water is more developed in near-term fetuses. Finally, fetal hypoxemia had no effect on mean arterial pressure and heart rate in young fetuses; however, in near-term fetuses, a significant increase in blood pressure and a decrease in heart rate were observed. In summary, it appears that the response of the fetal kidney to hypoxemia depends on the degree of fetal maturation.
TL;DR: The use of two paternal genetic markers, a cell surface antigen and nuclear Y chromatin, to identify fetal cells in maternal blood permits us to conclude that these cells are present in the mother's circulation, as early as 15 weeks gestation.
Abstract: The presence of fetal cells in the maternal circulation during pregnancy has been suggested by repeated observations of small numbers of cells containing Y chromatin or a Y chromosome in the blood of pregnant women. With the fluorescence-activitated cell sorter (FACS), we have used antibodies to a paternal cell surface (HLA) antigen, not present in the mother, to select fetal cells from the lymphocyte fractions of a series of maternal blood samples, collected as early as 15 weeks of gestation. These sorted cells have been examined for a second paternal genetic marker, Y chromatin. Y chromatin-containing cells were found among the sorted cells from prenatal maternal blood specimens in 8 pregnancies subsequently producing male infants whose lymphocytes reacted with the same antibodies to paternal antigen used for sorting with the FACS. In each of 17 pregnancies resulting in male infants who failed to inherit the antigen detected by the antibodies used for cell sorting, Y chromatin-containing cells were not found prenatally. The use of two paternal genetic markers, a cell surface antigen and nuclear Y chromatin, to identify fetal cells in maternal blood permits us to conclude that these cells are present in the mother's circulation, as early as 15 weeks gestation. Further development of the techniques reported here could lead to widespread screening of maternal blood samples during pregnancy for detection of fetal genetic abnormalities.
TL;DR: The results suggest that the metabolic reactions converting P5 to androgens are activated in the human fetal testis within a short time range between 8-11 weeks of gestation, which is possibly a consequence of increased 3 beta-hydroxysteroid dehydrogenase activity.
Abstract: The steroidogenic activity of human fetal testes during early and midgestation was monitored by analyzing 58 individual fetal testes (aged 6–20 weeks of pregnancy) for endogenous pregnenolone (P5), progesterone, 17-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, testosterone (T) and estradiol. A clear increase in testicular steroid concentrations, especially in those of T and other 3-keto-4-ene steroids, occurred between 8–11 weeks of gestation and reached maximum between 11–14 weeks. The three steroids present in highest concentrations were P5 androstenedione, and T (maximum concentrations, 1.9–2.7 ng/mg wet tissue). The levels of all of the C-19 steroids measured decreased clearly between weeks 14–20 of gestation, whereas those of the C-21 steroids, P5, progesterone, and 17-hydroxyprogesterone, remained relatively high. Our results suggest that the metabolic reactions converting P5 to androgens are activated in the human fetal testis within a short time range between 8–11 weeks of gestatio...
TL;DR: The decrease in fetal prostacyclin production in pre-eclampsia is not related to gestational age; furthermore, it is also seen in other chronic placental insufficiency states.
TL;DR: The apparent normal 5-HT lamination pattern produced by fetal raphe axons in adult hippocampus is consistent with reports that neuronal transplantation is effective in reversing the anatomical and behavioral deficits produced by homotypic denervation of a terminal field.
TL;DR: The development of specific and sensitive electroimmunoassays for a recently identified high molecular weight alpha-2 mobile pregnancy-specific protein (pregnancy-associated plasma protein A, PAPP-A or SP4) is described, which have permitted the detection of circulating levels of P APP-A as early as the fifth week of pregnancy.
01 Jan 1981
TL;DR: This chapter will review the changes in and regulation of fetal hormonal levels and their relation to male genital differentiation.
Abstract: In the normal male fetus a 46XY genotype leads to gonadal male sex; thereafter it is the hormones produced by the fetal testis which imprint a male pattern onto the indifferent embryonic genital precursor (Jost, 1953; Wilson, 1978). This chapter will review the changes in and regulation of fetal hormonal levels and their relation to male genital differentiation.
Journal Article•
TL;DR: Timed cultures of Pasteurella haemolytica 12296 strain in RPMI 1640 medium demonstrated that optimal cytotoxin production occurred during the logarithmic phase (peaked at 6 hours) and decreased during the stationary phase of bacterial growth, indicating that the cytot toxin may be antigenic in cattle.
Abstract: Timed cultures of Pasteurella haemolytica 12296 strain in RPMI 1640 medium (with L-glutamine, pH 7.4) were used to determine the correlation between cytotoxin production and the age of the culture. Cytotoxic activity was measured by a 51Cr-release assay and trypan blue exclusion test with bovine neutrophils as target cells. Results demonstrated that optimal cytotoxin production occurred during the logarithmic phase (peaked at 6 hours) and decreased during the stationary phase of bacterial growth. The cytotoxin was concentrated by sequential ultrafiltration on Diaflo XM 50, XM 100, and XM 300 membranes. The cytotoxin was retained on an XM 300 membrane. These studies indicated that the molecular weight of cytotoxic substance was 300,000 or more. The cytotoxin was heat labile, oxygen stable, and susceptible to extremes of pH and killed bovine neutrophils and mononuclear leukocytes. It was not hemolytic to bovine or ovine RBC. The cytotoxic activity was inactivated by trypsin and did not contain any detectable endotoxin. Bovine fetal serum and serum collected before immunization from neonatal calves did not neutralize the cytotoxic effects of toxin on neutrophils. However, adult bovine serum from 6 cows and an antiserum (against the cytotoxin) neutralized the cytotoxin, as revealed by both the 51Cr-release assay and the trypan blue exclusion test. This was confirmed by transmission electron microscopy. These results indicated that the cytotoxin may be antigenic in cattle. The significance and implications of these findings to bovine pasteurellosis are discussed.
TL;DR: Maternal serum AFP measurement can be used as a screening procedure to identify neural tube defects providing a rigorous protocol is followed and a reliable assay with adequate controls is employed.
Abstract: Alpha fetoprotein (AFP) is the major protein of fetal serum and most resembles albumen, which replaces it shortly after birth. It is produced by fetal liver and passes into the amniotic fluid (AF) via fetal urine. A small amount crosses the membranes into the maternal circulation. Excluding fetal blood contamination, elevated AF/AFP levels indicate fetal demise or one of several abnormalities. Maternal serum (MS) AFP measurement can be used as a screening procedure to identify neural tube defects providing a rigorous protocol is followed. This requires that a laboratory establish its normal range of MS/AFP levels between 15 and 20 weeks gestation, employ a reliable assay with adequate controls, and has recourse to genetic counseling as well as expert sonography, amniocentesis and amniography if necessary. Pregnancy is the only normal situation in which AFP is present after birth. It may be present in high levels in certain malignancies and has been useful in monitoring their recurrence. This article will review the history, biochemistry, and different assays of AFP in AF and blood as well as the indications and limitations for their use.
TL;DR: In the normoglycemic, late-gestation fetal lamb, there appears to be little glucogenesis, whereas glucogenesis may become significant during fasting-induced fetal hypoglycemia.
Abstract: Fetal umbilical glucose uptake was compared with simultaneous measurements of glucose turnover and utilization rates in 12 pregnant sheep, at a mean of 137 days gestational age (range, 118–146 days...
TL;DR: Information concerning immunity development in humans was initially obtained during the course of devising immunization schedules which were suitable for infants, but as pregnancies were terminated by hysterotomy on account of proven or suspected congenital infection an increased number of fetal tissues became available for study.
Abstract: Information concerning immunity development in humans was initially obtained during the course of devising immunization schedules which were suitable for infants. The recognition of the severe structural malformations which could result from congenital infection stimulated interest in the immunological responsiveness of the fetus and in ways by which the immunity development of the fetus might be adversely affected by the infection. As pregnancies were terminated by hysterotomy on account of proven or suspected congenital infection an increased number of fetal tissues became available for study. One use that these aborted tissues were put to was the grafting of infants with severe congential immunodeficiencies, mostly severe combined immunodeficiency (reviewed by Kay 1972). Some of the recipients developed graft versus host disease, making it clear that fetal lymphocytes were not necessarily incompetent. Further studies on fetal lymphoid tissues were therefore directed towards identifying a critical stage in lymphoid development when the cells could learn to tolerate a new host but would retain their potential for anti• microbial immunity. Since hysterotomy has been abandoned as a common means for terminating pregnancy, and since the advent of rubella immunization.
TL;DR: The desialylated form of D2‐protein was found only in postnatal rats and it increased to a slight maximum at postnatal day 25 in forebrain, and postnatalday 35 in cerebellum, and the findings are discussed in relation to the possible role of D 2‐protein as an adhesion molecule.
Abstract: The D2-protein exists as a sialylated form in fetal and in perinatal rat brain, and as a desialylated form in adult rat brain. By crossed Immunoelectrophoresis the concentrations and amounts of these forms were investigated during ontogeny of both forebrain and cerebellum. The concentration of sialylated D2-protein reached two peaks during ontogeny. The first peak occurred in forebrain around embryonic day 13, and in cerebellum just after birth. In both brain areas it coincided with the periods of major neuronal migration. The second peak occurred in forebrain around postnatal day 6 and in cerebellum around postnatal day 20, during the initial period of synaptogenesis in both brain areas. Moreover, the desialylated form of D2-protein was found only in postnatal rats and it increased to a slight maximum at postnatal day 25 in forebrain, and postnatal day 35 in cerebellum. The findings are discussed in relation to the possible role of D2-protein as an adhesion molecule.
TL;DR: After parturition vitamin D is functional in maintaining a normocalcemia as early as 3 days postpartum and its importance increases with age of the neonate.
TL;DR: The reduced incorporation of 3H-thymidine into fetal DNA, together with the increased fetal mortality observed in dams treated specifically with acetaldehyde during pregnancy, suggests that acetaldehyde is implicated in the mechanism of teratogenesis associated with the fetal alcohol syndrome.
Abstract: Incorporation of 3H-thymidine into DNA was significantly diminished by treatment with ethanol and acetaldehyde in regenerating rat liver, rat ceils in culture, and rat fetal tissues. Reduced incorporation was especially marked in the fetal central nervous system and was observed with both compounds at levels similar to those reported to occur in human alcoholics. The reduced incorporation of 3H-thymidine into fetal DNA, together with the increased fetal mortality observed in dams treated specifically with acetaldehyde during pregnancy, suggests that acetaldehyde is implicated in the mechanism of teratogenesis associated with the fetal alcohol syndrome.
TL;DR: Results indicate the presence of an embryonic somatomedin in humans, and the fetal brain RRA-SMA may provide a reliable index of fetal growth.
Abstract: A radioreceptor assay utilizing human fetal brain plasma membrane as matrix and somatomedin A as ligand (fetal brain RRA-SMA) was developed. Increased levels of fetal brain RRA-SMA were found in the fetal circulation. The concentration was approximately 4-fold higher in the fetal as compared to the adult human. At birth, values fell within the adult range. In contrast, adult somatomedins determined by somatomedin radioimmunoassay were undetectable in the fetus and below the adult range at birth. Levels of fetal brain RRA-SMA were decreased in fetuses with different clinical disorders. In healthy newborns at cesarean section a significant correlation between serum fetal brain RRA-SMA values and birth weight and length was found. These results indicate the presence of an embryonic somatomedin in humans. The fetal brain RRA-SMA may provide a reliable index of fetal growth.