Biological research in pregnancy and perinatology最新文献

Vasopressin (AVP) concentration was measured by radioimmunoassay from unextracted plasma of nonpregnant women and during first and third trimester of pregnancy. In nonpregnant state it was 3.5 +/- 0.6 pg/ml, in first trimester 4.3 +/- 1.8 pg/ml, but in third trimester 6.5 +/- 0.4 pg/ml and significantly (p less than 0.001) higher than in nonpregnant state. AVPase activity was investigated by in vitro method whereby the decrease of AVP concentration during incubation was measured. In first trimester pregnancy, the AVPase activity was 3-fold and in third trimester 20-fold when compared with nonpregnant level.

Cord plasma levels of endorphins and catecholamines were correlated with the values of cord blood gas analysis and with hemodynamic parameters in 11 newborns (group A) delivered by elective cesarean section and in 18 newborns (group B) born spontaneously by vaginal route. All infants were in a good condition. No statistically significant differences were found in the mean cord plasma levels of adrenaline (A), noradrenaline (NA) and immunoreactive beta-endorphin (ir beta-E) between groups A and B. After spontaneous labor in group B a highly significant negative correlation was found between plasma NA level and pH and a positive correlation between NA and carbon dioxide tension in cord arterial blood and between NA and the short-term variability of the fetal heart rate before birth. Cord plasma A and ir beta-E did not show such correlations. These findings show that cord plasma level of NA is a sensitive indicator of minor stress during normal labor. After birth, during the first two hours of life, the mean plasma level of ir beta-E decreased in group B after vaginal delivery, but remained at a higher level in group A after elective cesarean section. This shows that the mode of delivery influences the neonatal endorphin secretion.

Ultrasound can provide important information for the assessment of cervical incompetence (C.I.) and for the follow-up of pregnant women submitted to a cervical cerclage. Attention must be paid to the technical problems involved in the examination and the physiological variations in anatomical configuration must be taken into account.

The concentration of sodium, potassium, magnesium and calcium in the tissue of 12-, 19- and 21-day pregnant rats as well as in controls and in their fetuses have been measured. Practically no changes in sodium, potassium or magnesium concentrations were detected in either maternal or fetal tissues. However, an important calcium accretion in fetuses was observed in the last quarter of intrauterine development, which paralleled a noticeable decrease in calcium stores of bone and kidney, which was followed by muscle calcium loss on day 21. This huge mobilization of calcium and stability of the other metals studied have been discussed in the light of available information as to their availability in the diet and their handling by rat placenta.

Among the most recent methods for investigation of proteins in biological fluids SDS polyacrilamide-gel-electrophoresis (SDS-PAGE) and isoelectrofocusing (IEF) have recently been introduced into laboratory practice. The present investigation was performed on 14 samples of amniotic fluid obtained during the third trimester in pregnancies complicated by Rh-sensitization and polyhydramnios in which protein concentration was higher than in normal pregnancies. The obtained results suggest that IEF analysis seems to have a selective advantage in allowing the separation of bands which cannot easily be recognized with SDS electrophoresis. These bands detected by IEF and present in amniotic fluid during late pregnancy seem to be related to some molecular weight lipoprotein fractions and we suggest that they might be used as a possible marker for monitoring fetal lung maturation. In conclusion we think that it would be of great interest to evaluate the usefulness of IEF analysis in examining amniotic fluid obtained during pregnancies complicated by polyhydramnios and Rh-sensitization.

Blood samples to be analysed for lead, cadmium and mercury were taken from 417 pregnant women not occupationally exposed to these metals. Each subject was paired with a non-pregnant woman of the same age (+/- 2 years), socio-economic status, alcohol and tobacco status. Most of the inter-individual variations observed in earlier studies were confirmed in the control group. Among the pregnant women, however, such variations in blood metal levels appeared to be somewhat different compared to the control women according to the parameters studied: age of the women, alcohol and tobacco consumption. Furthermore, the study of the evolution of blood levels of lead, cadmium and mercury throughout pregnancy revealed a significant decrease in cadmium levels during the first half of pregnancy. A similar tendency was observed for lead but this did not attain statistical significance.

Recently, the presence and the concomitant release with catecholamines of metenkephalin and other pro-enkephalin A deriving peptides have been demonstrated in the adrenal medulla of various mammals and man. As high amounts of catecholamines are released in the newborn at delivery, probably following the stress of parturition, a similar release of met-enkephalin and other pro-enkephalin A deriving peptides from the newborn chromaffin tissue may be hypothesized. In the present study we investigate the occurrence of met-enkephalin-like immunoreactivity and enkephalinase (quite a specific enkephalin degrading enzyme) in cord and newborn plasma at different hours after birth. Our results show the presence of high met-enkephalin-like immunoreactivity levels in cord and newborn plasma with respect to normal adult values. On the contrary, cord blood enkephalinase activity was lower than in adult subjects and further decreased during the first hours of life. A positive correlation was found between the two parameters. These data seem to indicate a release of met-enkephalin-like peptides from the newborns' sympathoadrenal tissue following the stress of delivery and in the first hours of life.

Although breast-feeding in renal transplant patients has been discouraged because of the potential risk to the infant from the immunosuppressive drugs, two of our patients chose to breast-feed their infants for 3-4 months period. Serum and human milk IgA and zinc concentration were measured by the immunodiffusion and atomic absorption spectrophotometry method, respectively. Human milk IgA and zinc levels were at the lower normal limits one week posttransplant and were found to be slightly decreased after three months of lactation. Although serum IgA and zinc levels were not measured to breast-feed infants they were both found to have normal blood counts, no increase in infections and above average growth rate.

The content of calcium, copper, iron, magnesium and zinc in the plasma, liver and kidney of control female and male, as well as pregnant rats on days 12 and 19 after a i.p. injection of 4 mg/kg of nickel was studied. The content of 19-day conceptuses was also measured. The injection of nickel provoked significant alterations in the essential metal homeostasis, more marked in the case of pregnant rats, with additional differences between male and female animals. In general, nickel provoked increases in metal concentrations in tissues, with diverse changes in plasma. In a number of tissues and metals, the effects lasted up to 48 hours after the single injections, long after the nickel being washed off the animal. The results suggest some sort of long-lasting nickel effect upon metal homeostasis, which is postulated not to be directly related to acute effects and which is enhanced by pregnancy.

In the rat, mid-pregnancy seems to be related to an active nitrogen metabolism. In the present work we studied how the plasma homeostasis and the urinary nitrogen excretion of urea and ammonia could be altered during this period. Urea and ammonia plasma levels do not show significant changes, whereas, their urinary excretion is increased at mid-pregnancy. When urea levels in urine are corrected by the urinary creatinine content and the food intake, we found lower values in pregnant than in virgin rats. Thus, the organic nitrogen is more spared during pregnancy than before impregnation without any significant changes in the urea and ammonia plasma concentrations.