Biological research in pregnancy and perinatology最新文献

We have previously shown that the human placenta possesses a potent platelet antiaggregatory activity which is probably due to an ADPase. This led us to investigate platelet aggregation (in response to: adenosine diphosphate; adrenaline; collagen) in maternal blood samples obtained pre- and post-delivery and in cord blood at the time of delivery. Platelet aggregation in maternal samples did not differ significantly pre- and post-delivery, nor did it differ significantly from platelet aggregation observed in age-matched, non-pregnant women. On the other hand, platelets obtained from cord blood samples were insensitive to adrenaline even when very high concentrations (100 mumol/l) of this agonist were used. This lack of response to adrenaline could be overcome by incubation of cord platelet rich plasma (PRP) with sub-aggregatory doses of collagen or ADP or by standing PRP at room temperature for 2-3 h. ADP-induced aggregation was also diminished in cord PRP samples but this was only significant at the lowest ADP concentrations. The physiological significance of these findings is unclear but it may be of relevance that plasma catecholamine levels are high in neonates. Some adults show a defect of aggregation with absence of response to adrenaline, suggesting that neonatal platelet function patterns may persist in some adults.

Plasma kinetics of dihydralazine (50 mg p.o.) was studied in 11 women in late pregnancy. The distribution pattern between maternal and umbilical plasma was investigated in 12 patients who received 75-100 mg dihydralazine per day. In one patient amniotic fluid concentration and in another breast milk levels could be evaluated twice. Plasma concentrations of dihydralazine were very low. Continuous plasma level curves could be estimated in only four of the examined patients. In every case dihydralazine concentrations were higher in umbilical blood than in maternal plasma. Concentrations found in breast milk were clinically negligible.

Hemostatic regulation is partly maintained by antiaggregatory and vasodilative prostaglandins (PGI2, PGE1, PGD2) and by the proaggregatory and vasoconstrictive Thromboxane A2. PGI2-Synthesis is regulated by a plasma factor (PF). This plasma factor and the platelet sensitivity (PS) to PGI2 and PGE1 decrease during pregnancy towards term. In preeclampsia PF and PS is more decreased than in healthy pregnant women. Both parameters increase significantly after delivery. The decreased values of PF and PS in preeclampsia demonstrate a dysregulation of hemostasis in preeclampsia.

Since its early diagnostic application in the study of pregnancy, ultrasonography (US) has been widely employed in the detection of fetal malformations. Head abnormalities, recognized through the evaluation of brain and skull structures, accounted for the majority of these observations. We report here on a case of holoprosencephaly, a rare malformation (incidence is around 1/16,000 live births according to Roach et al. [1975]) diagnosed and monitored up to delivery by multiple US examinations.

In vitro synthesis of inhibin-like activity was localized in the fetal part of the human placenta. Of the various hormones, hCG stimulated inhibin synthesis while progesterone, estradiol, LHRH and prostaglandin inhibited the synthesis. Prolactin did not significantly alter the inhibin synthesis.

458 unrelated healthy women at various gestational ages were examined for serum heat-stable alkaline phosphatase (HSALP) activity. The sample was subdivided into four groups according to the compatibility mating type in the ABO and Rh systems: double compatible, ABO incompatible, Rh incompatible and double incompatible. The results confirm the exponential growth of serum placental isoenzyme as a function of gestational age and show that the moment of appearance of the placental isoenzyme is six weeks earlier in double incompatible matings.

Commercial reversed-phase cartridges were used for the separation of 3H2O which was produced in an aromatization reaction of androstenedione by human placenta in vitro. The assay is simple, rapid and reproducible. Metabolites originating from androstenedione were separated and quantified by thin layer chromatography. The microsomal fraction exhibited the highest aromatase activity which was inhibited (54%) by aminoglutethimide (500 microM) and by about 30% by alpha-naphthoflavone. Aromatase activity was not inhibited by known inhibitors of xenobiotic metabolism such as metyrapone or SKF 525A or by xenobiotic substrates such as 7-ethoxycoumarin or benzo(a)pyrene. Placental aromatase activity was not affected by maternal cigarette smoking. No correlation between aromatase and aryl hydrocarbon hydroxylase activities in the placentas from both smoking and non-smoking mothers was found. These results show that the aromatase activity in human placenta is catalysed by a distinct form of cytochrome P-450 which is different from forms with xenobiotic-metabolising activity, and also show that the aromatase activity is similar in placentas from both smoking and non-smoking mothers.

Concentrations of placental protein 10 (PP 10) were measured by radioimmunoassay and found to be detectable but very low in nonpregnant women and in men. In an assay of 223 samples from normal pregnancies, the mean PP 10 level was 2.7 +/- 1.0 ng/ml (mean +/- SD) at 6 to 7 weeks of gestation. The level of PP 10 in maternal sera increased gradually as pregnancy progressed to a high of 40.2 +/- 19.0 ng/ml at 38 to 39 weeks, followed by a slight decrease to 28.9 +/- 15.6 ng/ml at 40 to 41 weeks. The coefficients of variation were 8.6 to 16.2% in diurnal variation and 10.3 to 34% in day-to-day variation. Relatively lower PP 10 levels were observed in maternal sera in threatened abortion with poor prognosis, toxemia of pregnancy, intrauterine fetal death and placenta previa.

Infants require higher therapeutic doses (per unit body weight and surface area) and also tolerate higher doses of digoxin than adults. In contrast premature and even mature newborns are more susceptible to digoxin intoxications. Serum protein binding contributes to the apparent volume of distribution. Since the volume of distribution for digoxin shows an age-dependency, the present study was designed to determine the plasma protein binding of digoxin in premature and mature newborns as well as in infants and adults. Using the equilibrium dialysis method the fraction of digoxin bound to serum protein averages 30% in all groups studied. Thus protein binding could not account for the differences in dosage and susceptibility of digoxin in newborns and infants as compared to adults.

Ovaries from 8-week-old female NMRI mice, treated with 5 micrograms diethylstilbestrol (DES) daily for the first 5 days after birth were studied for progesterone synthesis in vitro, using 3H-pregnenolone as precursor, and assayed for progesterone content using radioimmunoassay (RIA) technique. The plasma levels of progesterone were measured with RIA. These results were compared with those from control ovaries from females in different phases of the estrous cycle. Values for radioactivity representing 3H-progesterone were significantly higher after 1-hour incubation of ovarian homogenate from DES treated females than in homogenates of ovaries from any phase of the normal estrous cycle. The ovarian content of progesterone was similar in DES exposed ovaries and ovaries from females in proestrous or estrous but lower in DES ovaries than in diestrous ovaries. The plasma levels of progesterone were in the same range in DES treated females and diestrous females but higher in DES females than in estrous or proestrous females.