Joachim W. Dudenhausen

Pre‐eclampsia is not Associated with Changes in the Levels of Regulatory T Cells in Peripheral Blood

The acceptance of the semi‐allogeneic fetus within the maternal environment requires tolerance mechanisms not fully characterized yet. Normal pregnancy is known to be associated with a Th2 profile. Furthermore, regulatory T cells (Tregs) were proposed to regulate the Th2/Th1 balance at early stages of pregnancy. Treg may avoid the shift to a Th1 profile, thus preventing miscarriage. Accordingly, spontaneous abortion is characterized by a Th1 dominance and diminished levels of Treg. The major aim of the present work was to investigate if pre‐eclampsia, a late immunological complication of pregnancy, is characterized by similar hallmarks.

Influence of Long-Term Beta-Mimetic Therapy on the Lecithin Content of Amniotic Fluid

The lecithin content of 157 amniotic fluid samples taken from 60 patients who had been treated with Fenoterol over a long period of time (longer than 30 mg/daily per os for 14 days; intravenous infusion for longer than 7 days) was calculated thin-layer chromatographically according to Kynast and Saling. These lecithin levels were statistically compared with the levels in a control (Wilcoxon test). It emerged that the lecithin levels in the long-term beta-mimetic therapy group were significantly lower, i.e., from 33/0 to 39/6 (33/0-34/6, p less than 0.05; 35/0-39/6, p less than 0.01). The answer to the question how often levels occur in the long-term group which are below the as critical described level of 3 mg Lec/100 ml amniotic fluid appears to be clinically important. It is shown that values below the critical level from 33/0 to 39/6 are much more frequent in the long-term beta-mimetics therapy group than in the control group. There is no known explanation for this. It was concluded that the application of beta-mimetics in cases of long-term tocolysis should only be discontinued when the lecithin content of the amniotic fluid lies above the critical limit of 3 mg Lec/100 ml.

Quantitative determination of phospholipids in amniotic fluid by high-performance liquid chromatography

SummaryA new quantitative analytical method for the determination of phospholipids in amniotic fluid by high performance liquid chromatography (HPLC) is described. In addition to the main compounds, phosphatidylcholine (lecithin) and sphingomyelin, the so-called minor phospholipids, phosphatidylglycerol, phosphatidylinositol and phosphatidylethanolamine can also be determined. Separation is achieved using a guard-column of Lichrosorb Si 60 and an analytical column of Lichrosorb DIOL. Acetonitrile/water is used as mobile phase at an elevated temperature. By determining the recovery rates, the within-run and the between-run precision, it was shown that sufficient accuracy and precision could be achieved for all the parameters examined. The method is highly sensitive, the detection limit for sphingomyelin is 0.2 μg and 0.1 μg for all the other components. A single determination of 5 phospholipids in an amniotic fluid sample takes about two hours. By performing simultaneous extractions it is possible to analyse 5 samples per day.

Ion-Exchange Chromatography and Ion-Pair Chromatography. Complementation of HPLC Analysis of Amino Acids in Body Fluids by Pre-Column Derivatization Using Ortho-Phthaldialdehyde

Abstract The determination of free amino acids in some human body fluids using reversed phase high performance liquid chromatography and pre-column derivatization with ortho-phthaldialde-hyde/mercaptoethanol is a highly sensitive and reproducible method. However not all amino acids can be determined using this easily automatizable method. Several special amino acids, as for example cystin which contains sulphur, can be determined using a separation procedure of ion-exchange and/or ion-pair chromatography. These separation procedures are described here.

Determination of the Pulmonary Surfactant-Associated Protein SP-B in Amniotic Fluid with a Competition ELISA

A competition ELISA was developed with polyclonal chicken antibodies, with which the surfactant-associated protein B (SP-B) can be measured in amniotic fluid. The SP-B content from 240 amniotic fluid samples taken from uncomplicated pregnancies between the 29th and 42nd week of gestation was determined. The SP-B content rose from the 33rd week of gestation onwards to a median level of 800 ng SP-B/ml amniotic fluid at the end of the pregnancy. In the 3 cases examined up to now of infants with a respiratory distress syndrome the levels lay below 300 ng SP-B/ml.

Correlation between transcutaneous pCO2 and the corresponding values of fetal blood — a study at a measuring temperature of 39 °C

Continuous transcutaneous monitoring of fetal carbon dioxide partial pressure (tcpCO2) may become an important new method for investigating the physiology and pathophysiology of the fetus during labor, as well as an additional tool for fetal surveillance. In order to contribute to the standardization of this newly developed method, we measured tcpCO2 during labor in 105 fetuses. We then compared the transcutaneous pCO2 with the pCO2 of fetal blood gas analysis; the correlation between these two parameters was significant. The relationship between transcutaneous pCO2 and the pH from fetal scalp blood is described, as is the influence of the stage of labor on the correlation between transcutaneous monitoring and blood samples. tcpCO2 during labor appears to be a helpful additional tool, especially in fetuses with pathologic heart rate patterns in whom multiple fetal blood gas analysis would otherwise be necessary.

Simultaneous Determination of Phospholipid Classes and the Major Molecular Species of Lecithin in Human Amniotic Fluid by HPLC

Abstract Phospholipid classes in human amniotic fluid, whose quantitative determination plays an important role in obstetrics for diagnosing lung maturity in the fetus, are separated through normal phase chromatography by HPLC. In this study an already known chromatographic system is described with which not only the phospholipids, but also phosphatidylcholine partly after being combined with both its fatty acid residues, is separated. This separation implies the fatty acid residues which are of greatest interest to the obstetrician. A mass or evaporative light-scattering detector was used for the detection.

Some Data on the Pattern of Lymphocyte Subsets in Blood During the Perinatal Period

As a prerequisite for studies of possible effects of prenatal exposure on lymphocytes in newborn, the knowledge of peculiarities of lymphocyte patterns in the blood of normal, unexposed newborn is essential. In our special case, information on both the human blood and the experimental model to be used is necessary.

Lecithin Content of Amniotic Fluid in Twin Pregnancies with and without Long-Term Tocolytic Therapy

During the period from January 1973 to October 1979, 55 transabdominal amniocenteses were performed on 40 twin pregnancies and the lecithin content of the amniotic fluid obtained was established in order to determine the fetal lung maturity. The lecithin determination was performed densitometrically according to Kynast and Saling. Through long-term tocolysis in twins the surfactant production rate is delayed in each phase of the pregnancy, whereas in a collective without long-term tocolysis one can reckon with sufficient fetal lung maturity from the 35th week onwards.

Kinetics of the degradation of NG−nitro−L−arginine and its methyl ester in human umbilical vein blood and amniotic fluid

The kinetics of the degradation of the inhibitors of the nitric oxide synthesis, NG-nitro-L-arginine methyl ester and NG-nitro-L-arginine, were examined in human amniotic fluid and umbilical vein blood. The reaction rate constants were calculated or estimated using the time-controlled concentration course of both substances. These concentrations were measured by high-performance liquid chromatography with two different separation systems: ion-exchange chromatography and ion-pair chromatography. Using this method, either NG-nitro-L-arginine methyl ester and/or NG-nitro-L-arginine were added to 18 samples of amniotic fluid, 33 samples of plasma and 21 samples of uncentrifuged umbilical vein blood samples; subsequently these samples were used for measurement. The degradation of the two individual study substances can be described by a uni-unimolecular two-step consecutive reaction. Thereby, NG-nitro-L-arginine methyl ester decomposes to NG-nitro-L-arginine. Although NG-nitro-L-arginine decomposed further, the decomposition product could not be identified. The average of the reaction rate constants for NG-nitro-L-arginine methyl ester/NG-nitro-L-arginine was determined, yielding the following values: 0.032 h-1/0.00047 h-1 in amniotic fluid, 0.029 h-1/0.00384 h-1 and 0.00074 h-1 in plasma and 0.80 h-1/0.00060 h-1 in uncentrifuged umbilical vein blood. During the first hours after sampling, these reaction rate constants could be used to approximate the concentrations of NG-nitro-L-arginine methyl ester and NG-nitro-L-arginine at the time of sampling.