Michael J. Sinosich

Maternal blood platelet physiology and luteal-phase endocrinology as a means of monitoring pre- and postimplantation embryo viability following in vitro fertilization

The discovery that the fertilized mouse ovum triggers an increased demand for platelets and results in thrombocytopenia during the preimplantation phase of pregnancy provides a monitor for embryo survival and viability. This paper reports a study in which the platelet count was significantly reduced throughout the human preimplantation phase of pregnancy and returned to normal following embryo implantation. The human embryo was shown to produce a platelet activating factor in vitro which caused the reduction in platelet count after embryo transfer. This factor in the embryo culture medium could be measured using a bioassay which provided a means of assessing embryo viability prior to transfer. Some women showed no reduction in platelets after transfer. These embryos failed to produce a platelet activating factor in vitro and pregnancy was not established. Other women displayed a reduction in platelets following transfer but failed to become pregnant. All of these women had elevated luteal-phase plasma E2 levels compared to pregnant patients, which may have interfered with the implantation process. Our observations provide a possible rapid and simple means for monitoring the viability of human embryos cultured in vitro and the survival of embryos in utero.

Assessment of ovulation by ultrasound and estradiol levels during spontaneous and induced cycles.

Both Graafian follicle growth and subsequent ovulation were studied in 45 menstrual cycles of 28 patients by the estimation of plasma estradiol levels and by the measurement of follicle size and number by ultrasound. Twenty spontaneous ovulatory cycles were studied as controls compared with twenty cycles in which ovulation was induced by clomiphene and five cycles in which ovulation was induced by human pituitary gonadotropin. The means of the peak estradiol levels during the cycles in which one follicle was present were 1553.1 +/- 87.8 pmoles/liter in the spontaneous cycles and 2296.8 +/- 163.4 pmoles/liter in the clomiphene-treated cycles. Ultrasound was shown to be complementary to endocrine profiles because the number and diameter of Graafian follicles could be measured accurately by this technique.

Progesterone antagonist (RU 486) for cervical dilation, labor induction, ,and delivery in monkeys: effectiveness in combination with oxytocin

A progesterone antagonist (RU 486), combined with oxytocin, was effective in achieving cervical dilation, labor induction, and early delivery in near-term monkeys. Effects of RU 486 included accelerated flow of colostrum and transiently enhanced weight gain in infants. No overt toxicity on fetuses, mothers, or newborns was detected with the use of a single oral dose of 25 mg.

Does ultrasound examination render biochemical tests obsolete in the prediction of early pregnancy failure

Summary. Serum levels of fetal, placental and maternal hormones and proteins [β‐fetoprotein (AFP), human chorionic gonadotrophin, human placental lactogen. schwangerschaftsprotein 1, pregnancy associated plasma protein‐A (PAPP‐A), oestradiol‐17β, progesterone, pregnancy zone protein] were measured in 108 women with bleeding during the first half of pregnancy. Ultrasound examination at the time of each blood sampling revealed a fetal heart action on at least one occasion in 77 women. Spontaneous abortion occurred in 42 pregnancies, 31 of these showed no ultrasound sign of fetal life, whilst the fetal heart action was observed repeatedly until abortion in the remaining 11 women. Abnormally low levels of PAPP‐A were most likely to indicate pregnancy failure, in particular if the fetal heart action was seen at the time of blood sampling. The predictive value, sensitivity and relative risk of a single depressed PAPP‐A level were respectively 49, 89 and 41%, the predictive value of a normal result being 99%. With the exception of AFP, all other biochemical indices examined were consistently in the normal range in this group of women. If ultrasound findings were not considered, the biochemical indices were of comparable value in the prediction of spontaneous abortion. PAPP‐A levels were uniformly depressed in all patients who spontaneously aborted, frequently weeks before this event, in the presence of a live fetus.

Potassium regulation and progesterone-aldosterone interrelationships in human pregnancy: A prospective study

Little is known about the intrinsic renal and hormonal regulation of potassium excretion in pregnancy despite major alterations in many of the potassium regulatory factors. Forty primigravid women on an unrestricted diet were studied during the second and third trimesters and exhibited constant absolute and fractional potassium excretion despite a significant increase in plasma aldosterone concentration between these stages. The plasma progesterone level rose significantly between studies but closer analysis showed no correlation between individual changes in plasma aldosterone concentration and progesterone between trimesters. In the 14 subjects studied post partum, baseline absolute potassium excretion was not significantly altered but filtered potassium fell and fractional potassium excretion tended to rise. After dietary sodium manipulation at these stages, absolute potassium excretion, fractional potassium excretion, and progesterone were unaltered despite significant changes in plasma aldosterone concentration and sodium excretion. These results suggest that potassium excretion is held constant throughout pregnancy and that renal tubular potassium reabsorption adjusts appropriately to the increased filtered potassium load. Progesterone does not appear to be involved in the acute regulation of potassium or sodium excretion but may have effects on sodium and potassium excretion that are constant, proportional to its placental production, and unresponsive to endogenous changes in mineralocorticoid production.

Maternal recognition of pregnancy prior to implantation: methods for monitoring embryonic viability in vitro and in vivo.

Embryo transfer is the step in the in vitro fertilization (IVF) and embryo transfer (ET) procedure that is the least successful. Well over 80% of all embryos transferred failed to result in the establishment of pregnancy.’.’ It is currently not possible to detect the presence of the embryo in utero prior to implantation. This leaves a period of more than a week in which it is not possible to monitor the fate of the transferred embryos. The absence of such a monitor has previously precluded investigation of the causes of this high embryonic loss. This period of pregnancy has eluded study because there has been little biochemical evidence for the production of embryonic signals prior to implantation. Some recent studies have shown that changes in maternal physiology occurred during the preimplantation phase of pregnancy and that these changes were solely a consequence of the presence of the embryo.’*4 We report here that an increased vascular demand for blood platelets, resulting in mild thrombocytopenia, was an initial maternal response to pregnancy in mice and humans. Monitoring the maternal platelet count in early pregnancy allowed assessment of embryonic viability in utero. This thrombocytopenia was caused by the production of a platelet activating factor(s) by the fertilized ovum. Monitoring the production of this factor by the embryo in vitro, using a bioassay, provided a means of assessing embryo quality. Monitoring early pregnancy-associated thrombocytopenia (EPAT), the production of an embryo-derived platelet-activating factor(s) (EDPAF), and the maternal luteal-phase endocrine profile was shown to be a powerful tool for (1) assessing

Prenatal screening in the first trimester of pregnancy

Prenatal screening for fetal abnormalities is an accepted part of modern obstetric management. Improvements on current screening procedures need to address increased diagnostic efficacy and earlier diagnosis. This study evaluates the diagnostic efficacy of PAPP‐A and Fβ‐hCG in the detection of first trimester pregnancy abnormalities, including Down syndrome (DS). Of 731 pregnant volunteers, obtained from a mature age population undergoing chorionic villus sampling (CVS), 17 DS and 11 compromised (six numerical (excluding sex chromosome) aneuploidies, five spontaneously failed) pregnancies were detected. Application of an algorithm, which combines PAPP‐A and Fβ‐hCG levels with maternal age, detected 66·6 per cent of DS pregnancies for a five per cent false positive rate. Similarly, for a 1·2 per cent recall rate, 72·7 per cent of compromised pregnancies were detected. This report supports the notion that prenatal screening at 9–12 weeks of pregnancy is achievable with PAPP‐A and Fβ‐hCG quantitation. Whereas mid‐gestational screening targetted the detection of fetal abnormalities, screening earlier in pregnancy will detect other pregnancy‐related abnormalities, in addition to aneuploidy.

In-vitro secretion of prostanoids by placental villous cytotrophoblasts in pre-eclampsia

Villous trophoblasts isolated from term placentae of normal pregnancies, and pregnancies complicated by chronic hypertension or pre-eclampsia, were examined over 7 days in primary culture. Low levels of prostaglandin E2 and prostacyclin (measured as 6-keto prostaglandin Fl alpha) were secreted by trophoblast cells from all three clinical groups. Secretion was maximal at day 1 and decreased exponentially thereafter. Thromboxane secretion also fell sequentially from day 1. Thromboxane secretion by pre-eclamptic trophoblasts was three to four times that of cells from normal or chronically hypertensive subjects. Prostanoid secretion by isolated cultured cytotrophoblasts was not dependent on aggregation or morphological alteration, nor related to changes in progesterone or human chorionic gonadotrophin production. Because the local maternal circulation is exposed to substances secreted by this cell population, thromboxane could be the trigger for vasoconstriction and coagulation found within the maternal uteroplacental circulation in pre-eclampsia.

Comparison of different antibody preparations against pregnancy‐associated plasma protein‐A (PAPP‐A) for use in localization and immunoassay studies

Summary. Four antibody preparations against pregnancy‐associated plasma protein (PAPP‐A) were compared in order to find an explanation for the contradictory results published on tissue localization, clinical usefulness and biological function of PAPP‐A. One of the preparations studied was a rabbit anti‐PAPP‐A antiserum which has been offered for general scientific use (Bischof et al. 1979). Only the IgG fraction of anti‐PAPP‐A antisera which appeared to be monospecific and had been further absorbed with fetal connective tissue gave specific uniform staining of the cytoplasm of the syncytiotrophoblast exclusively. Circulating PAPP‐A could not be detected by RIA employing this IgG preparation in the non‐pregnant state, or before 18 days after conception. Circulating PAPP‐A could be detected in all seven pregnant women studied within 4 weeks after conception. Identical results were obtained with a commercially available IgG fraction against PAPP‐A.

Seminal Plasma Levels of PAPP-A in Normospermic and Oligospermic Men and Tissue Localization of PAPP-A in the Male Genital Tract

Radioimmunoassay, gel filtration, isoelectric focusing, and immunoperoxidase methods were used to study the levels, properties, and localization of pregnancy-associated plasma protein A (PAPP-A) in the human seminal plasma and male genital tract. Seminal plasma specimens from 20 normospermic and 20 oligospermic men were studied. PAPP-A was found in 30 of 40 samples, the levels ranging from undetectable to 135 micrograms/liter (median 35 micrograms/liter) in the normospermic group and from undetectable to 111 micrograms/liter (median 21 micrograms/liter) in the oligospermic group. There was no significant difference in the PAPP-A levels between the two groups, and no correlation was observed between the seminal plasma PAPP-A levels and the volume of seminal plasma or the sperm count or the viability of spermatozoa. Serial dilutions of seminal plasma and PAPP-A standard yielded parallel dose-response curves, and incubation with seminal plasma did not result in any change in the elution pattern of [125I]PAPP-A in gel filtration. PAPP-A-immunoreactive material from seminal plasma eluted as two peaks, the major one corresponding to the elution volume of purified PAPP-A and the minor eluting more slowly. The isoelectric point of seminal plasma PAPP-A was 4.3-4.7 and that of term pregnancy serum was 4.2-4.6. In the immunoperoxidase staining, PAPP-A was seen in the epithelium of the prostate, seminal vesicle, and the ampullar part of the vas deferens but not in the testis, epididymis, proximal parts of vas deferens or urethra. The results confirm the occurrence of PAPP-A in the seminal plasma but do not suggest any clinical utility for seminal plasma PAPP-A measurements.(ABSTRACT TRUNCATED AT 250 WORDS)