The relationship between plasma oestrone sulphate concentrations in pregnant dairy cattle and calf birth weight, calf viability, placental weight and placental expulsion

A total of 54 Holstein-Friesian cows (13 primiparous and 41 multiparous) was used to study maternal plasma oestrone sulphate (E1S) during pregnancy and its relationship to birth weight and viability of calves and time required for placental expulsion after calving. Plasma samples were obtained from the tail vein of cows once every month from days 90 to 180, every 2 weeks from days 181 to 270, and every day from day 270 of gestation to parturition. The E1S concentrations were measured by radioimmunoassay, and birth weight, placental measurements, neonatal viability and the period from calving to placental expulsion were recorded. E1S concentrations were correlated positively (0.71 > or = r > or = 0.32, P < 0.05 or P < 0.01) with calf birth weight and weights of cotyledons, intercotyledonary membranes and total placenta from days 210 of gestation to 1 day prepartum. Calf birth weight was correlated positively (p < 0.01) with the weight of the cotyledons (r = 0.87), intercotyledonary membranes (r = 0.78) and total placenta (r = 0.88). In addition, E1S concentrations were positively correlated (0.63 > or = r > or = 0.28, P < 0.05 or P < 0.01) with the neonatal viability after day 195 of pregnancy, and were negatively correlated (-0.29 > or = r > or = -0.55, P < 0.05 or P < 0.01) with the intervals from parturition to placental expulsion after 225 days of pregnancy. The results suggest that variation among dams for circulating E1S levels during late pregnancy may be caused by variation of placental development and ability for oestrogen production and conjugation, and they may influence fetal growth, neonatal viability and retained placenta.     

Placental growth patterns affect birth weight for given placental weight

BACKGROUND: An important contributor to fetal growth is growth of the placenta, the fetus' sole source of nutrients and oxygen. Here we use placental growth measures (larger and smaller disk diameters, reflecting the laterally expanding chorionic plate, and disk thickness) to test the hypothesis that placental growth patterns, while associated with placental weight and birth weight, measure placental functional efficiency, and will have independent effects on the feto-placental weight ratio (FPR). METHODS: Placental measures were available from 23,313 participants in the Collaborative Perinatal Project delivered between 34 and 43 completed weeks. Continuous variables were analyzed by regression for associations with placental weight, birth weight, and FPR, to further explore effects of placental growth patterns on the FPR (lateral chorionic plate growth and chorionic disk thickness were grouped as low, normal, and high values). The relationships of the nine resultant combinations of placental growth categories to the FPR using birth weight adjusted for gestational age, infant gender, parity, and African American race were analyzed (ANOVA). RESULTS: As chorionic disk area and thickness increased, birth weight and placental weight increased, and the FPR decreased (each p < .0001) after adjustment for gestational age, parity, race, and infant gender. Small, thin placental disks had an adjusted FPR of 8.46; the largest, thickest placentas had an adjusted FPR of 6.33. The nine categories of FPRs were significantly different, consistent with chorionic plate area and disk thickness combining to determine the FPR. CONCLUSIONS: Patterns of placental growth, relating to different functional dimensions of the placenta, deliver a different birth weight for a given placental weight.     

Predictors of ratio of placental weight to fetal weight in multiethnic community.

OBJECTIVE--To determine whether placental ratio is influenced by maternal ethnic origin, obesity, hypertension, and haematological indices of iron deficiency anaemia. DESIGN--Observational study. SETTING--District general hospital in Birmingham. SUBJECTS--692 healthy nulliparous pregnant women, of whom 367 were European, 213 Asian, 99 Afro-Caribbean, and 13 of other or undocumented ethnic origin. MAIN OUTCOME MEASURES--Placental ratio and maternal body mass index, blood pressure, and haematological indices. RESULTS--Though birth weight and placental weight were lower in Asian women than in other groups, mean placental ratio was similar in Asian (19.5% (SD 3.3%)), European (20.0% (4.0%)), and Afro-Caribbean women (20.4% (5.3%)). Gestational age at birth was the main predictor of placental ratio in the univariate analysis (r = -0.34, P < 0.001) and multivariate analysis. The only other significant predictor of placental ratio in multivariate analysis was maternal body mass index, which was positively associated with placental ratio (r = 0.1, P = 0.01). Mean (SD) placental ratio was not significantly higher in women who developed gestational hypertension (20.4% (4.5%)) and pre-eclampsia (23.3% (7.3%)) than in normal women (19.8% (3.8%)). No evidence of a relation between placental ratio and first antenatal visit haemoglobin concentration or mean cell volume was detected, and placental ratio was not associated with change in mean cell volume during pregnancy or with third trimester serum ferritin concentration. CONCLUSIONS--These data do not support the proposed association between poor maternal nutrition and increased placental ratio. The association between high placental ratio and adult hypertension may be confounded by genetic and environmental factors associated with maternal obesity (and possibly maternal hypertension).     

Birth weight and placental proximity in like-sexed twins.

In addition to zygosity, the type of placentation has proven to be an important variable in twin studies. A number of quantitative traits in human twins have been found to be influenced by chorion type. Our study confirms an earlier finding that there is larger within-pair birth weight variability in dichorionic twins with fused placentas than in those with separate placentas. This finding emphasizes the importance of detailed twin placental examinations to help identify traits that may be influenced by prenatal environmental influences.     

Characterization of human placental neuraminidases. Stability, substrate specificity and molecular weight.

1. At least two components of neuraminidase can be distinguished on the basis of thermolability and sedimentability by using the artificial fluorogenic substrate 4-methylumbelliferyl N-acetyl-alpha-D-neuraminate. 2. In crude homogenates, thermodenaturation at 25 degrees C showed a biphasic curve corresponding to component A (half-life, 21 min) and B (half-life, 85 min). The two components were partially resolved by centrifugation. A being soluble and B sedimentable. Both had similar pH-activity curves (pH optimum, 4.4), Km values (A, 0.10 mM; B, 0.06 mM) and molecular weight as determined by radiation inactivation (A, 67000; B, 63000). 3. The soluble A form was still aggregated or bound to membranous debris since almost all neuraminidase activity was eluted near or at the void volume of a Sephacryl S-300 column. 4. Both soluble and sedimentable fractions of placenta hydrolysed the GD1A ganglioside and N-acetyl-neuraminyl-D-lactose linearly for 12 h but no fetuin hydrolysis was detected. 5. The neuraminidase activity with the artificial fluorogenic substrate was inhibited by N-acetylneuraminyl-D-lactose but not by the GD1A ganglioside. These preliminary results suggest that there exist two closely related enzymes hydrolysing both the artificial substrate and N-acetylneuraminyl-D-lactose and a third one hydrolysing the GD1A ganglioside exclusively.     

Variability of placental expression of cyclin E low molecular weight variants

Cyclin E, a G(1) cyclin serving to activate cyclin-dependent kinase 2, is the only cyclin gene for which alternative splicing leading to structurally different proteins has been described. Different cyclin E proteins are present in tumor tissues but absent from normal (steady) tissues. Cyclin E contributes to the regulation of cell proliferation and ongoing differentiation and aging. Because trophoblast has invasive properties and differentiates into syncytium and placental aging may develop at term, we examined cyclin E protein variants in human placenta. Placental samples were collected from 27 deliveries between 33 and 41 wk and were compared with ovarian cancer (positive control). Both placental and tumor tissues showed seven cyclin E low molecular weight (LMW) bands migrating between 50 and 36 kDa. Placental expression of cyclin E showed certain variability among cases. Lowest cyclin E expression was detected in normal placentas (strong expression of Thy-1 differentiation protein in villous core and low dilatation of villous blood sinusoids). Abnormal placentas (significant depletion of Thy-1 and more or less pronounced dilatation of sinusoids) showed significant increase either of all (early stages of placental aging) or only certain cyclin E proteins (advanced aging). Our studies indicate that a similar spectrum of cyclin E protein variants is expressed in the placental and tumor tissues. Low cyclin E expression in normal placentas suggests a steady state. Overexpression of all cyclin E proteins may indicate an activation of cellular proliferation and differentiation to compensate for developing placental insufficiency. However, an enhanced expression of some cyclin E LMW proteins only might reflect an association of cyclin E isoforms with placental aging or an inefficient placental adaptation.     

Fetal and placental weight relationships in the albino rat near term.

The relationship of fetal weight to placental weight was examined in 34 albino rats on day 22 of gestation. The influence of maternal weight, fetal position and the number of fetuses in the litter and each uterine horn were assessed also. There was no indication that rats with heavier placentas had heavier or lighter fetuses. However, within each litter, placental weight was weakly correlated (r = 0.297, p less than 0.01) with fetal weight. Maternal weight at mating, although positively related to the number of corpora lutea, was not related to mean fetal or placental weight. The number of fetuses in the litter was negatively related to placental weight but there was no apparent relation to fetal weight. Fetuses and placentas at the ovarian end of the horn were significantly lighter than those at the vaginal end. The strength of the fetal weight:placental weight correlation in the rat is compared to those in other species.     

Altered placental expression of PAPPA2 does not affect birth weight in mice

Background  

Pregnancy-associated plasma protein A2 (PAPPA2) is an insulin-like growth factor binding protein (IGFBP) protease expressed in the placenta and upregulated in pregnancies complicated by pre-eclampsia. The mechanism linking PAPPA2 expression and pre-eclampsia and the consequences of altered PAPPA2 expression remain unknown. We previously identified PAPPA2 as a candidate gene for a quantitative trait locus (QTL) affecting growth in mice and in the present study examined whether this QTL affects placental PAPPA2 expression and, in turn, placental or embryonic growth.