正常足月产妇羊水组织因子水平与妊娠高凝状态、羊水栓塞的关系研究

目的探讨正常足月产妇羊水中的组织因子(TF)水平与妊娠高凝状态及羊水栓塞的关系。方法选取2013年1月至2014年12月该院待产的正常足月妊娠产妇158例,检测产妇血浆、羊水、羊水上清液及羊水沉渣中的TF和组织因子途径抑制物(TFPI)水平。结果羊水沉渣TF水平为(1 409.36±120.34)ng/L,明显高于血浆、羊水及羊水上清液水平,差异有统计学意义(P0.05);血浆TF水平为(30.17±6.49)ng/L,明显低于羊水各标本水平,差异有统计学意义(P0.05);羊水沉渣TFPI水平为(9.46±1.77)g/L,明显低于血浆、羊水及羊水上清液水平,差异有统计学意义(P0.05);血浆TFPI水平为(22.19±5.16)g/L,明显高于羊水各标本(P0.05);羊水及羊水上清液TF和TFPI水平差异无统计学意义(P0.05);羊水、羊水上清液、羊水沉渣中TF与TFPI呈负相关关系(P0.05),其中羊水沉渣相关性最强(r=-0.903,P0.05),血浆标本TF与TFPI无相关性(P0.05)。结论正常足月产妇羊水TF含量较高,而TFPI较低,可能在羊水栓塞的发生机制中起一定的临床作用。     

Stable isotope dilution analysis of very long chain fatty acids in plasma, urine and amniotic fluid by electron capture negative ion mass fragmentography.

A sensitive and selective stable isotope dilution electron capture negative ion chemical ionization mass fragmentography method applying pentafluorobenzyl derivatives was developed for the accurate quantitation of very long chain fatty acids. This technique allowed detection of 1-5 pg of each compound and was applied to plasma (100 microliters), amniotic fluid (1 ml) and urine (1 ml). Normal concentrations were established and the concentrations in samples of selected patients with classified peroxisomal disorders were determined. In plasma samples of all patients the C26:0/C22:0 ratios were elevated (range 0.03-0.43), compared to the control ratios (range 0.003-0.021). The ratio C26:0/C22:0 was elevated in four of five amniotic fluid samples from fetuses with peroxisomal disorders (range 0.18-0.54) when compared with controls (range 0.05-0.25). An elevation of the ratio C26:1/C22:0 was observed in all five amniotic fluid samples (range 0.22-0.60 vs. 0-0.08 in controls). Urinary C26:0 concentrations were lower than in plasma and amniotic fluid and diagnostic ratios were not elevated in patients with peroxisomal disorders.     

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.     

Prolactin in amniotic fluid: its correlation with maternal plasma prolactin.

Prolactin concentrations in amniotic fluid from 319 women with normal pregnancies and 29 women with complicated pregnancies were determined by radioimmunoassay. Prolactin levels varied from 36 ng/ml to 1800 ng/ml mean +/- S.D. = 408 +/- 297) in the normal pregnancy group but showed no definite pattern of rise or fall during pregnancy. No difference in levels was found in complicated pregnancies. Prolactin concentrations in the plasma from 203 of these women were also assayed. The levels in the amniotic fluid were about 9 fold higher than those in the plasma. There was no significant correlation between amniotic fluid and plasma levels of prolactin.     

Differences in the carbohydrate moieties of plasma and amniotic fluid fibronectins as revealed by crossed immunoaffinity electrophoresis with concanavalin A

Human fibronectins isolated from pooled human plasma and amniotic fluid were studied as to differences in their carbohydrate moieties. The chemical analyses showed that amniotic fluid fibronectin is different from adult plasma fibronectin in carbohydrate content and composition while there seems to be no significant differences in amino acid composition. Crossed immunoaffinity electrophoresis with free concanavalin A, as well as rocket immunoelectrophoresis with immobilized concanavalin A intermediate gel, indicated that amniotic fluid fibronectin has little or no reactivity with this lectin while adult plasma fibronectin is strongly reactive. Fetal cord plasma fibronectin apparently interacted with concanavalin A, but its reactivity was weaker than that of adult plasma fibronectin. Fibronectin isolated from ascitic fluid of an ovarian cancer patient which was examined in additional experiments showed much weaker Con A-reactivity than fetal cord plasma fibronectin. These results suggest that fibronectins from various body fluids differ in their carbohydrate structures.     

The thromboplastic activity of lung surfactant in amniotic fluid and its application to prenatal assessment of fetal lung maturity

Based on the fact that both tissue thromboplastin and lung surfactant show lamellar structures under the electron microscope and belong chemically to lipoprotein, the thromboplastic activity of lung surfactant in amniotic fluid was studied by measuring plasma recalcification time. The results obtained were as follows (1) The surfactant fractions isolated from amniotic fluid and rabbit or pig lung showed the thromboplastic activity with dose response. (2) The thromboplastic activity of amniotic fluid increased with advancing gestational age. (3) It was found that the thromboplastic activity determined by plasma recalcification time was parallel with the surfactant concentration of amniotic fluid. (4) The shortening rate of plasma recalcification time in amniotic fluid could estimate well the risk of RDS, and the critical value for RDS was assumed to be about 33%.     

足月妊娠羊水超声组织定征及临床应用价值研究

目的：对足月孕妇羊水进行超声回声强度（EI）定量分析，为临床及时诊断胎儿宫内窘迫提供客观的羊水性状指标。方法：对27例足月妊娠孕妇羊水池进行EI定量测定。根据手术分娩后羊水性状分为正常羊水组（16例）及羊水粪染组（11例），比较两组间EI灰阶（GS）、分贝（dB）差异。结果：羊水粪染组灰阶及分贝最大值明显高于正常羊水组。结论：超声组织定征可用于临床前羊水性状的监测。     

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.     

Fibronectin determination in pregnancy

The levels of fibronectin were determined by immunoturbidimetric assay in two populations: (a) plasma of healthy nonpregnant and pregnant women, and in amniotic fluid of healthy pregnant females; (b) plasma of umbilical cord blood of healthy newborns and of newborns with sepsis. Fibronectin concentrations of amniotic fluid showed a significant decrease during pregnancy, but the changes of plasma fibronectin levels were not significant in this period. In newborn sepsis, the levels of plasma fibronectin were significantly decreased. We did not find a significant difference between the fibronectin concentration of umbilical cord blood of premature infants compared to mature infants.     

Identification of 2-hydroxybutyric acid in human amniotic fluid.

2-Hydroxybutyric acid has been identified in human amniotic fluid by combined gas chromatography and mass spectrometry. It was present in all 22 specimens examined of gestation 15 to 20 weeks and 30 to 40 weeks. The concentration of 2-hydroxybutyric acid in amniotic fluid was about 100 times less than that of the predominant acid, lactic acid.     

Ultrasonographic demonstration of floating particles in amniotic fluid

This prospective study of 131 pregnant women was designed to determine the incidence and significance of floating particles in amniotic fluid. Floating particles ranging in size from 1 to 5 mm were seen in the amniotic fluid of pregnant women at 15 to 40 weeks' gestation. Since vernix is rarely present before 35 weeks' gestation, a source other than flakes of vernix must be sought to explain the floating particles in amniotic fluid in early gestations. There was no significant difference in the sizes or numbers of particles at different gestational ages (from 15 to 40 weeks). Therefore, it is concluded that ultrasonographic demonstration of floating particles in amniotic fluid cannot be considered an indicator of fetal maturity.     

High molecular weight angiotensinogen: a pregnancy associated protein

Although it was previously recognized that human amniotic fluid contained appreciable quantities of angiotensinogen, it remained unknown what fraction of the total is high molecular weight angiotensinogen. Fractionation of human amniotic fluid showed that high molecular weight angiotensinogen represents the major component of total angiotensinogen; 58% for 11 normotensive pregnant women and 67% for 12 hypertensive pregnant women. In contrast to plasma where high molecular weight angiotensinogen is elevated in hypertensive pregnant women as compared to normotensive pregnant women, no such difference exists for amniotic high molecular weight angiotensinogen. Serum and amniotic fluid high molecular weight angiotensinogen were compared in six subjects, and no significant correlation was found. In fetal cord blood, high molecular weight angiotensinogen represented only 5.8% of the total angiotensinogen. The site of synthesis of high molecular weight angiotensinogen remains unknown but these data suggest that it is produced in the placenta or in the maternal uterine tissue. Therefore, we propose that human high molecular weight angiotensinogen should be classified as a pregnancy-associated protein.     

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.     

Angiotensin I-converting enzyme in amniotic fluid

Angiotensin I-converting enzyme (ACE) is present in human amniotic fluid. We characterized the enzyme by both its antigenic and enzymatic properties. Using a specific direct radioimmunoassay, ACE was quantified and characterized in each of the 19 samples tested. Mean level was 136 +/- 83 ng/ml. Amniotic ACE completely crossreacted, like that in plasma and kidney, with antibodies raised against the lung enzyme. ACE activity in amniotic fluid averaged 8.7 +/- 5.6 microU/ml using Hip-His-Leu as substrate and was significantly correlated with ACE antigen levels. ACE was not associated with the cells or the free intracellular organelles in amniotic fluid, and the enzyme was present in soluble form. Angiotensinase activity and high levels of kininase activity were found in amniotic fluid. Inhibition studies with captopril and anti-human ACE antibodies suggest that angiotensinases and kininases other than ACE were also present. Because renin, mostly in inactive form, and angiotensinogen were also found in these amniotic fluids, it appears that a complete, although not fully activated, renin angiotensin system is present in amniotic fluid and fetal membranes during pregnancy.     

Subjective versus objective evaluation of amniotic fluid volume of pregnancies of less than 24 weeks' gestation: how can we be accurate?

This study was undertaken to compare subjective versus objective ultrasonic evaluation of amniotic fluid volume in pregnancies of less than 24 weeks' gestation. Amniotic fluid volume was subjectively (visualization without ultrasonic measurements) and objectively (visual interpretation with ultrasonic measurements) evaluated in 42 singleton pregnancies undergoing termination. The actual amniotic fluid volume was then determined using a dye-dilution technique. The women evaluated were in their mid-20s, primarily African American, and between 15 and 23 weeks' gestation. There was no significant difference in the total number of correct estimates of amniotic fluid volume when the data were stratified by level of operator experience (P = .34), ultrasonic technique (P = .33), or the combined correct subjective versus combined correct objective estimates (P = .68). We have concluded that the accuracy of amniotic fluid volume assessment in pregnancies of less than 24 weeks is not influenced by the level of operator experience or the type of ultrasonic measurement.     

产前诊断中羊水细胞培养方法的研究

目的:探讨产前诊断中羊水细胞培养方法及不同羊水量对培养结果的影响。方法:155例羊水标本,以不同羊水量分为两组,分别以平皿盖玻片法和培养瓶法进行培养,比较两种培养方及不同羊水量的培养结果。结果:平皿盖玻片联合培养瓶法培养一次成功并获满意核型151例,成功率97.4%;两种培养方法比较,两组中均以平皿盖玻片法成功率高于培养瓶法;平皿盖玻片法6~8mL与15~20mL羊水的培养成功率无显著差异。结论:羊水细胞培养中,平皿盖玻片法优于培养瓶法,前者具有成功率高、收获时间早、容易区分真假嵌合型的优点,更适用于羊水量少、孕周偏大者;产前诊断中推荐以培养瓶法联合平皿盖玻片法行羊水细胞培养。     

A serine protease activity of human serum albumin towards 4-methylumbelliferyl-guanidinobenzoate (MUGB) and diisopropyl fluorophosphate (DEP): implications for the use of MUGB reactivity in amniotic fluid in prenatal diagnosis of cystic fibrosis

4-methylumbelliferylguanidinobenzoate (MUGB) reactivity in plasma from patients with cystic fibrosis and in amniotic fluid from pregnancies leading to children with cystic fibrosis, has been reported to be significantly decreased. We have so far been unable to confirm these findings and have therefore reexamined this reactivity using diisopropylfluorophosphate (DEF), another active site titrant of serine proteases. We have shown that MUGB and DFP are reacting with the same molecules in plasma and amniotic fluid. Using crossed immunoelectrophoresis and SDS-polyacrylamide gel electrophoresis of 3H-DFP labelled plasma and amniotic fluid we have obtained strong evidence that the main contribution of MUGB and DFP reactive protein in plasma and amniotic fluid is identical to serum albumin. The use of MUGB reactivity in amniotic fluid in pregnancies at risk for cystic fibrosis must therefore be reconsidered.     

Measurement, Characterization, and Source of Somatostatin-like Immunoreactivity in Human Amniotic Fluid

Somatostatin-like immunoreactivity (SLI) is widely distributed in tissues and biological fluids. To determine whether SLI is also present in amniotic fluid, samples obtained by amniocentesis from 30 normal and 27 abnormal pregnancies were studied by radioimmunoassay. Direct incubation of [(125)I-Tyr(1)]tetradecapeptide somatostatin (SRIF) with amniotic fluid resulted in 89% tracer degradation. Damage was reduced to <5% when samples were acidified and boiled before the assay. With this technique, SLI was detectable in all normal amniotic fluid samples; the mean level at 15-20 wk of gestation (320+/-55 pg/ml, n = 15) being 4.5 times higher than the mean at 32-43 wk (70+/-12 pg/ml, n = 15) (P < 0.001). In cases of preeclampsia (n = 6), gestational diabetes (n = 5), anencephaly (n = 1), and meningomyelocele (n = 1), SLI values were in the normal range, but in one juvenile diabetic and one patient with chronic renal failure, SLI was undetectable (<10 pg/ml). In a pair of monochorionic diamniotic twins, SLI levels were very different (33 and 197 pg/ml), which suggests that fetal factors are more important than materno-placental ones in determining amniotic fluid SLI. Serial dilutions of amniotic fluid showed parallelism with standard SRIF. When concentrates of pooled amniotic fluid were chromatographed on Sephadex G-25 columns, all SLI eluted in the void volume ahead of SRIF even after treatment with 8 M urea and dithiothreitol. This "big" SLI incubated in amniotic fluid showed 100% stability over 24 h at 37 degrees C, whereas SRIF was rapidly inactivated (t((1/2)) congruent with 7 min). Extracts of placenta and fetal membranes contained no SLI, but small amounts (6-20% of total amniotic fluid SLI) were found in cells from fresh fluid. Radioimmunoassay of SLI in extracts of seven paired cord arterial and venous plasma samples showed no arteriovenous gradient consistent with fetal origin of cord blood SLI. It is concluded that (a) amniotic fluid contains SLI which is of fetal origin and (b) normal levels vary with gestational age. The SLI has a higher molecular weight (>/=5,000) and is more stable in amniotic fluid than SRIF.     

Amino acid metabolism during starvation in human pregnancy

To evaluate the factors regulating gluconeogenesis in pregnancy, plasma amino acid levels were determined during the course of an 84-90 hr fast in physically healthy women studied during wk 16-22 of gestation (before undergoing therapeutic abortion), and in nonpregnant controls. The effect of pregnancy on the glycemic response to exogenous alanine administration during starvation was also investigated.In the nonpregnant group fasting resulted in a 2- to 3-fold increase in the levels of plasma valine, leucine, isoleucine, and alpha-aminobutyrate, while the concentration of alanine and glycine fell. In the pregnant group, the levels of most amino acids were significantly reduced in the postabsorptive state. With starvation, the plasma concentration of alanine fell more rapidly in the pregnant group and was significantly below that of the nonpregnant subjects for the first 60 hr of the fast. In contrast, a significant elevation in plasma glycine, serine, and threonine was observed in the pregnant group after 84 hr of fasting, whereas similar increments were not demonstrable until after 10 days of fasting in previously studied nonpregnant obese subjects. Paralleling the changes in maternal plasma, amniotic fluid levels of valine, leucine, and isoleucine increased while that of alanine fell during the fast.Although the plasma glucose concentration was lower in the pregnant group at termination of the fast, intravenous alanine administration (0.15 g/kg), resulted in a prompt, comparable increase (20-25 mg/100 ml) in plasma glucose in both groups of subjects.It is concluded that (a) pregnancy accelerates and exaggerates the hypoalaninemic and hyperglycinemic effects of starvation; (b) lack of key endogenous substrate rather than altered intrahepatic processes may limit hepatic gluconeogenesis in pregnancy and contribute to gestational hypoglycemia; (c) maternal caloric deprivation profoundly alters the levels of amino acids in amniotic fluid.     

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.