Prostate-specific antigen in amniotic fluid of normal and abnormal pregnancies

Objective: To examine if prostate-specific antigen (PSA) is present in amniotic fluid or maternal serum during pregnancy and if its presence is associated with fetal abnormalities.

Methods: Samples tested included amniotic fluids from 853 pregnant women for whom amniocentesis was performed; 312 nonpregnant women who donated blood; 259 pregnant women who donated blood at various gestational ages. Amniotic fluid or serum PSA was measured with an ultrasensitive time-resolved immunofluorometric procedure. 372 pregnancies were studied for the presence of genotypic or phenotypic fetal abnormalities.

Results: PSA was present in most amniotic fluids; the median PSA concentration increased from gestational week 11 to 22 and stabilized thereafter until delivery. The most prominent PSA concentration change occurred during gestational weeks 13–14. Pregnant women had significantly higher serum PSA concentrations than nonpregnant women; the pattern of serum fSA concentration change during pregnancy was similar to that of amniotic fluid; however, serum PSA concentrations were lower by a factor of 20–40. No association existed between amniotic fluid F'SA and maternal age, gender of fetus, or length of abstinence of mother from sexual intercourse. After gestational week 15, fetuses with trisomy 21 or 18, anencephaly, or renal disorders were associated with low amniotic fluid PSA levels.

Conclusion: Our data suggest that PSA may play a role in fetal development, especially at gestational ages between 13–20 weeks. The diagnostic usefulness of PSA in identifying fetal abnormalities remains to be determined.     

Tobramycin: Maternal-Fetal Pharmacology

To investigate the maternal-fetal transfer of tobramycin (TBM) and its distribution in the fetus, a single dose of 2 mg/kg was administered intramuscularly to 35 pregnant patients (13 first trimester, 22 second trimester) 0.5 to 34 h before hysterectomy. TBM concentration was assayed microbiologically in maternal serum, fetal tissues (placenta, brain, lung, liver, and kidney), and fluids (amniotic, cerebrospinal fluid [CSF], urine, and serum). Mean maternal serum half-life (1.54 h) and mean peak serum concentration of TBM were within ranges reported for nonpregnant adults. In fetal serum, half-life was 5.2 h, and TBM levels did not exceed 0.58 μg/ml. For intervals up to 34 h, the mean TBM concentration in placental tissues was 1.4 μg/g. Concentration differences related to fetal maturation were found for fetal CSF, amniotic fluid, and fetal kidney. No antimicrobial activity was found in the fetal CSF of >16 weeks' gestation. TBM was present predominantly in the second trimester amniotic fluid specimens. Fetal kidney concentrations reached 7.2 μg/g at 34 h after maternal drug administration. Higher TBM concentrations were related to advanced maturation of the fetal kidney. Second trimester fetal urine concentrations for TBM ranged from 0.1 to 3.4 μg/ml, and the fetal urinary half-life was 3.7 h. Knowledge of fetal pharmacology is essential for weighing the fetal benefits or risks of antimicrobial therapy for the infected gravid patient.     

Maternal Thyroid Function is the Major Determinant of Amniotic Fluid 3,3′,5′-Triiodothyronine in the Rat

3,3′,5′-triiodothyronine, (rT₃), is easily measured in human amniotic fluid (AF) during the second and third trimesters. To determine if AF rT₃ levels are maintained by either maternal or fetal thyroid function, or both, models of fetal hypothyroidism (FH), maternal hypothyroidism (MH), and combined maternal and fetal hypothyroidism (MFH) were developed in pregnant rats. Hormone analyses of maternal and fetal serum and AF were performed at term. Thyroxine (T₄) and 3,3′,5-triiodothyronine (T₃) were not detectable in the sera and AF of term fetuses in all groups. MFH rats were prepared by administration of methimazole to the dams, and in some experiments, by maternal thyroidectomy and a low iodine diet as well. In the MFH groups from the three experiments serum thyrotropin (TSH) was markedly elevated in the dams and in the fetuses. FH rats were prepared by administering T₄ by various routes to dams treated according to the MFH protocols and serum TSH was elevated in fetal serum. Analysis of FH maternal serum T₄, T₃, and TSH concentrations suggested mild maternal hyperthyroidism or hypothyroidism depending upon the schedule of T₄ administration. The MH groups were prepared by maternal thyroidectomy and in all experiments the fetuses had normal serum TSH concentrations. The degree of maternal hypothyroidism in the MH and MFH groups was equivalent. The mean concentration of AF rT₃ in normal rats in three experiments was 28.4±2.5 ng/dl (±SEM). In the three experiments, AF rT₃ was undetectable or markedly reduced in the MH and MFH rats and was normal in the FH rats. These results in the amniotic fluid could not be explained by transfer of rT₃ from fetal serum to the AF because fetal serum rT₃ concentrations in these various models did not correlate with AF rT₃ concentration. Furthermore, infusion of large doses of rT₃ in MFH dams resulted in a 35-fold elevation in maternal serum rT₃ concentration, a twofold elevation in fetal serum rT₃ concentration, and only a minimal increase in AF rT₃. These studies demonstrated that, in the rat, the maternal thyroid has the dominant role in maintaining AF rT₃, whereas little effect of fetal thyroid status on AF rT₃ could be demonstrated. Transfer of maternal rT₃ or of fetal rT₃ derived from maternal T₄ to the AF do not appear to be the mechanisms whereby the maternal thyroid maintains AF rT₃.     

Studies on serum apolipoproteins and lipids in amniotic fluid and neonatal urine

Amniotic fluid and neonatal urine were examined for the presence of lipids and serum apolipoproteins. Human apolipoproteins A-I, A-II, and ApoD found principally in serum high density lipoproteins were identified in both neonatal urine and amniotic fluid. A lecithin/sphingomyelin ratio of greater than 5 associated with fetal lung maturity was accompanied by the disappearance of A-II from amniotic fluid. Dissimilarities of total fatty acid composition of amniotic fluid when compared to cord serum or neonatal urine indicate other tissue sources for fatty acids found in amniotic fluid. In addition, the presence of serum apolipoproteins and lipids in both amniotic fluid and neonatal urine suggests that a least a portion of these constituents could be derived from fetal urine.     

Cocaine and metabolite concentrations in the fetal guinea pig after chronic maternal cocaine administration.

To determine the disposition of cocaine (COC) and metabolites after chronic COC exposure in the late gestation guinea pig, six time-bred Dunkin-Hartley guinea pigs were given 10 daily 6 mg/kg COC s.c. injections from day 50 of gestation. Maternal blood and urine, fetal cord blood, and brain and amniotic fluid were collected 1 hr after the last injection. There was no difference between maternal and fetal plasma COC concentrations. This may be due to the combined effect of lower protein binding and ion trapping of COC in the fetus. Benzoylecgonine was higher in maternal plasma, but benzoylnorecgonine was higher in fetal plasma. COC brain-to-plasma ratios were similar in the dam and fetus. Benzoylecgonine was the only metabolite that could be detected in the brain, but levels were too low to quantitate. COC accumulated 3 to 4 times plasma concentrations in the amniotic fluid and was directly proportional to fetal plasma COC concentrations. Benzoylnorecgonine in amniotic fluid accumulated to 2 times fetal plasma levels. The in vitro half-life of COC in amniotic fluid was 30 times longer than plasma elimination half-life in vivo. The high level and long duration of COC in amniotic fluid serve as a reservoir for prolonged fetal COC exposure.     

Unconjugated pteridines in amniotic fluid during gestation

Neopterin and biopterin concentrations were measured in amniotic fluid in 226 pregnancies from the 12th week of gestation to term. At mid-gestation, neopterin and biopterin levels were low and remained relatively constant between 12 and 26 weeks of gestation, whereas during the third trimester, a progressive increase was observed. Near term the values were greater than those in maternal serum and the higher neopterin to biopterin ratio suggested that pteridine concentration in amniotic fluid may reflect the maturation of pteridine metabolism in the fetus.     

Maternal Intravenous Administration of Azithromycin Results in Significant Fetal Uptake in a Sheep Model of Second Trimester Pregnancy

Treatment of intrauterine infection is likely key to preventing a significant proportion of preterm deliveries before 32 weeks of gestation. Azithromycin (AZ) may be an effective antimicrobial in pregnancy; however, few gestation age-approriate data are available to inform the design of AZ-based treatment regimens in early pregnancy. We aimed to determine whether a single intra-amniotic AZ dose or repeated maternal intravenous (i.v.) AZ doses would safely yield therapeutic levels of AZ in an 80-day-gestation (term is 150 days) ovine fetus. Fifty sheep carrying single pregnancies at 80 days gestation were randomized to receive either: (i) a single intra-amniotic AZ administration or (ii) maternal intravenous AZ administration every 12 h. Amniotic fluid, maternal plasma, and fetal AZ concentrations were determined over a 5-day treatment regimen. Markers of liver injury and amniotic fluid inflammation were measured to assess fetal injury in response to drug exposure. A single intra-amniotic administration yielded significant AZ accumulation in the amniotic fluid and fetal lung. In contrast, repeated maternal intravenous administrations achieved high levels of AZ accumulation in the fetal lung and liver and a statistically significant increase in the fetal plasma drug concentration at 120 h. There was no evidence of fetal injury in response to drug exposure. These data suggest that (i) repeated maternal i.v. AZ dosing yields substantial fetal tissue uptake, although fetal plasma drug levels remain low; (ii) transfer of AZ from the amniotic fluid is less than transplacental transfer; and (iii) exposure to high concentrations of AZ did not elicit overt changes in fetal white blood cell counts, amniotic fluid monocyte chemoattractant protein 1 concentrations, or hepatotoxicity, all consistent with an absence of fetal injury.     

The amnion regulates movement of fetally derived alpha-fetoprotein into maternal blood.

The present investigation documents that, under normal conditions, most fetally produced AFP reaches the maternal circulation via diffusion across the amnion from amniotic fluid. This has been determined by comparing maternal serum AFP levels with amniotic fluid albumin concentrations in paired samples. The proportionally demonstrated between them indicates a proportional, transamniotic exchange of the two proteins, each originating on opposite sides of the amnion. Albumin is known to reach amniotic fluid by transamniotic diffusion from maternal blood. All amnions restrict AFP movement into maternal serum, but some are distinctly more restrictive than others; in such cases, a relatively greater increase in amniotic fluid AFP concentration would likely have to occur from a fetal lesion before being reflected in maternal serum. Inconsistencies found in several paired samples identify that other variables may also influence passage of AFP to the mother.     

Human beta-endorphin and beta-lipotropin levels in maternal and fetal plasma and amniotic fluid

We measured beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) levels in human maternal and fetal plasma and amniotic fluid, simultaneously. It appeared evident that maternal circulating levels of beta-EP (n = 11, 163.9 +/- 12.9 pg/ml, mean +/- S.E.) and beta-LPH (n = 11, 413.0 +/- 25.9 pg/ml) at delivery were significantly (p less than 0.01) higher than those of maternal plasma at term (beta-EP; n = 4, 18.3 +/- 2.1 pg/ml, beta-LPH; 213.4 +/- 24.3 pg/ml) and those of amniotic fluid (beta-EP; n = 5, 8.5 +/- 1.2 pg/ml, beta-LPH; 215.1 +/- 44.9 pg/ml). Fetal beta-EP levels (n = 11, 79.1 +/- 5.8 pg/ml) were significantly (p less than 0.01) higher than those of amniotic fluid. These data suggest that the origin of amniotic fluid beta-EP may be an increased synthesis in the maternal and fetal pituitary gland but not in the placenta.     

Changes in alpha 1-acid glycoprotein serum concentrations and glycoforms in the developing human fetus.

alpha 1-Acid glycoprotein concentrations and reactivity to concanavalin A were measured in maternal and fetal serum and amniotic fluid obtained from 24 women undergoing diagnostic cordocentesis at 20 to 33 wk gestation and in 30 additional fetal sera (19 to 34 weeks gestation). Maternal alpha 1-acid glycoprotein serum levels were five to ten times higher than fetal and amniotic levels. Fetal alpha 1-acid glycoprotein levels were found to increase with advancing gestational age. Using crossed immunoaffino electrophoresis with concanavalin A, alpha 1-acid glycoprotein patterns were identical in maternal serum and amniotic fluid but totally different in fetal serum. The fetal concanavalin A pattern changed progressively during fetal life towards that of the newborn. These data confirm earlier assumptions of fetal synthesis of alpha 1-acid glycoprotein and provide normal reference values for alpha 1-acid glycoprotein in fetal serum. In addition, the specific fetal concanavalin A pattern indicates that the alpha 1-acid glycoprotein glycosylation process during fetal life differs from that in post-natal life.     

Immunochemical characterization and quantification of the sex steroid-binding protein (SBP) in human amniotic fluid

The sex steroid-binding protein (SBP) is a plasma protein whose concentration in the maternal circulation increases during pregnancy. Using monospecific antibodies raised against human SBP, we could demonstrate the antigenic identity of the protein in human amniotic fluid. In this fluid, we found that the SBP concentration was correlated with the total protein concentration throughout gestation. The concentration gradient of SBP between maternal serum and amniotic fluid was compared to that of other serum proteins, in relation to their relative molecular mass, and it was concluded that SBP enters amniotic fluid in a non-specific manner similar to that of other serum proteins. It is suggested that SBP could act to sequester the sex steroid hormones in amniotic fluid.     

Levels of free and conjugated catecholamines in amniotic fluid and in umbilical and maternal blood in patients undergoing cesarean section

A new radioenzymatic assay was used to evaluate free and conjugate catecholamines in six pregnant women who underwent cesarean section at term, in their newborns and in the amniotic fluid. Free adrenaline in maternal plasma was higher while noradrenaline and dopamine were lower at the moment of surgery than 24 hours before the operation. In umbilical plasma adrenaline and noradrenaline are higher than in maternal plasma while only traces of free dopamine and salsolinol are present. In the amniotic fluid high levels of free and conjugated salsolinol are found. The high level of free and conjugated catecholamines found in the umbilical plasma demonstrates that fetal sympathetic nervous system is strongly activated at delivery. Furthermore the presence of sulfoconjugating activity similar to that of the adult is confirmed.     

母血,羊水中IL—6和IL—8水平与绒毛羊膜炎关系的研究

目的探讨ＩＬ－６和ＩＬ－８在监测胎膜早破中的作用。方法采用酶联免疫吸附实验对４６例胎膜早破孕妇母血清、羊水中ＩＬ－６和ＩＬ－８水平进行监测，并以正常足月妊娠孕妇２０例做对照组。结果胎膜早破孕妇母血清中ＩＬ－６、８和羊水中ＩＬ－６、８水平均较正常足月妊娠组高，差异显著（Ｐ＜０．０１；Ｐ＜０．０５）；随着破膜时间延长母血中ＩＬ－６、８和羊水中ＩＬ－６、８有增加趋势；绒毛羊膜炎患者１３例，其母血、羊水中ＩＬ－６和ＩＬ－８水平均明显高于非绒毛羊膜炎患者（Ｐ＜０．０５）。结论测定胎膜早破孕妇羊水ＩＬ－６和ＩＬ－８水平对识别绒毛羊膜炎起辅助诊断作用。     

Fetal development: voice processing in normotensive and hypertensive pregnancies

Recent observation of maternal voice recognition provides evidence of rudimentary memory and learning in healthy term fetuses. However, such higher order auditory processing has not been examined in the presence of maternal hypertension, which is associated with reduced and/or impaired uteroplacental blood flow. In this study, voice processing was examined in 40 fetuses (gestational ages of 33 to 41 weeks) of hypertensive and normotensive women. Fetuses received 2 min of no sound, 2 min of a tape-recorded story read by their mothers or by a female stranger, and 2 min of no sound while fetal heart rate was recorded. Results demonstrated that fetuses in the normotensive group had heart rate accelerations during the playing of their mother's voice, whereas the response occurred in the hypertensive group following maternal voice offset. Across all fetuses, a greater fetal heart rate change was observed when the amniotic fluid index was above compared to below the median (i.e., 150 mm), indicating that amniotic fluid volume may be an independent moderator of fetal auditory sensitivity. It was concluded that differential fetal responding to the mother's voice in pregnancies complicated by maternal hypertension may reflect functional elevation of sensorineural threshold or a delay in auditory system maturation, signifying functional differences during fetal life or subtle differences in the development of the central nervous system.     

Diagnostic significance of analysis the energy metabolism substrates in biological fluids

Changes in energy metabolism substrates in biological fluids (venous and umbilical blood, urine, and amniotic fluid) were studied. Lactate concentrations were 2-4--fold increased in venous blood and 2-fold in umbilical blood. Urinary excretion of energy metabolism substrata was increased in women with gestosis. An increase of lactate concentration above 0.110 mmol/liter and of isocitrate concentration above 0.238 mmol/liter indicated fetal hypoxia.     

Study of soluble proteins from human amniotic fluid by fraction chromatography (author's transl]

The nature and origin of soluble proteins from human amniotic fluid have been investigated by gel filtration chromatography on Sepharose 6B and ion-exchange chromatography on Ecteola-cellulose. Each fraction has been studied by immunoelectrophoresis. Specific antisera against serum proteins, amniotic fluid proteins, fetal proteins and salivary proteins have been used. These various antisera showed that the amniotic fluid contains maternal proteins, but also more specific proteins from fetal origin such as beta2-microglobulin, urinary mucopolysaccharides, salivary proteins and carcinoembryonic antigen. These results not only confirm that amniotic proteins are essentially from maternal origin, but prove the important fetal contribution and emphasize the importance of the fetoplacental unit in the monitoring of high risk pregnancies.     

Human serum Zn-alpha2-glycoprotein in amniotic fluid

Human serum Zn-alpha2-glycoprotein (Zn-alpha2-GP) was found to be present in the amniotic fluid in the mean concentration of 0.98 +/- 0.40 mg/100 ml, which represents about one-tenth of its concentration in the maternal serum (9.65 +/- 1.18 mg/100 ml). Its concentration in the amniotic fluid was proportional to the amniotic fluid total protein and very approximately to the maternal serum Zn-alpha2-GP. The relationship between the maternal serum Zn-alpha2GP and the maternal serum total protein as well as between the amniotic fluid total protein and the maternal serum total protein was found to be not significant. The amniotic fluid Zn-alpha2-GP as well as the amniotic fluid total protein showed some increase during gestation to reach the highest values at the end of the second trimester. At present both the origin and significance of the amniotic fluid Zn-alpha2-GP are not known.     

白细胞介素-8、肿瘤坏死因子-α水平与胎膜早破合并宫内感染的相关性研究

目的：探讨孕妇血清和羊水白细胞介素-8（IL-8）、肿瘤坏死因子-α（TNF-α）水平与胎膜早破合并宫内感染的相关性和临床意义.方法：选取我院 2005年1月至2006年12月住院胎膜早破孕妇52例（研究组）,以及产科门诊定期产检的正常孕妇50例为对照组;采用酶联免疫法（ELISA）测定血清与羊水IL-8、TNF-α水平;同步取胎盘胎膜组织进行病理组织学检查.结果：研究组血清和羊水IL-8水平均高于对照组（P＜0.05）,而研究组TNF-α仅羊水水平高于对照组（P＜0.05）.研究组绒毛膜羊膜炎的发生率高于对照组（37%vs4%,P＜0.01）.羊水IL-8水平与血清 IL-8水平呈较好的正性相关（r=0.677,P＜0.01）;羊水TNF-α与羊水IL-8水平间亦有较好的正性相关（r=0.788,P ＜0.01）.结论：血清和羊水IL-8水平、羊水TNF-α水平与胎膜早破合并宫内感染有明显的正相关性,其中羊水IL-8的相关性最好.孕妇羊水IL -8、TNF-α水平可作为早期诊断胎膜早破合并宫内感染的指标.     

Binding of corticotropin-releasing hormone (CRH) in maternal and fetal plasma and in amniotic fluid

Placenta secretes corticotropin-releasing hormone (CRH) into the maternal and fetal circulation, but a CRH binding protein in plasma may decrease its biological activity. Using a charcoal adsorption method we found that 92% of added 125I-Tyr-CRH was bound to a binding protein in the nonpregnant plasma, 72% in the plasma at term pregnancy, 90% in umbilical cord plasma, 82% in the amniotic fluid in the second and 25% in the third trimester. CRH added to plasma inhibited the binding of 125I-Tyr-CRH over the concentration range of 0.1-8.8 nmol/l in plasma and of 0.1-2.2 nmol/l in amniotic fluid. There was a significant negative correlation (R = -0.80) between the binding capacity of the CRH-binding protein and CRH concentration in maternal plasma. Plasma or amniotic fluid was incubated with 125I-Tyr-CRH and subjected to gel filtration on Sephadex G-50. The bound radioactivity was eluted at the region of Mr 25-40 kDa and the unbound radioactivity at the location of synthetic CRH. Bound and unbound CRH concentrations were determined using charcoal adsorption method and gel filtration on Sephadex G-50 in ten maternal plasma samples at the third trimester of pregnancy. Following mean percentages were found to be bound: charcoal method 61.9 +/- 6.80% (SE) and gel filtration 62.8 +/- 6.33%. We conclude that the bulk of CRH is bound to a binding protein in maternal and fetoplacental circulation, whereas at term pregnancy the role of the binding is small in amniotic fluid.     

Pancreatic secretory trypsin inhibitor-like immunoreactivity in pancreatectomized patients

Pancreatic secretory trypsin inhibitor (PSTI) is a 6000-dalton peptide, that occurs in high concentrations in the pancreas and in pancreatic juice. It is thought to be synthesized by pancreatic acinar cells. We have recently reported the findings of an identical trypsin inhibitor at high concentrations in the urine of patients with gynecological malignancy. Therefore, we have named the inhibitor tumor-associated trypsin inhibitor (TATI). We have now studied patients who have undergone total pancreatoduodenectomy for pancreatic cancer or chronic pancreatitis. By radioimmunoassay (RIA), we found normal levels of this inhibitor in the serum and urine of pancreatectomized patients. The absence of pancreas was confirmed by measuring serum trypsin. By gel filtration and HPLC it was found that PSTI/TATI occurring in pancreatectomized patients was indistinguishable from that found in connection with pancreatitis and ovarian cancer.