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Biomedical subjects

B C Obiekwe

Publications and source records attributed to B C Obiekwe.

At least 19 recordsLinked to original sources
PubMed1986

Maternal oestriol levels reflect placental function rather than foetal function.

We have examined the relationship between foetal levels of E3 and DHEA-SO4 and the birthweight of the child. Levels of these steroids do not relate to birthweight--although the concentration of DHEA-SO4 was marginally but not significantly higher in infants of lower birthweight. These findings suggest that the placental conversion of foetal precursors, and not the level of the precursors themselves, determines the concentration of E3 in the mother. Measurement of E3 as a clinical test reflects the function of both the foetus and the placenta.

Birth Weight↗
PubMed1985

Which is the best placental function test? A comparison of placental lactogen and unconjugated oestriol in the prediction of intrauterine growth retardation.

Serum placental lactogen (hPL) and unconjugated oestriol (E3) levels were measured in 392 women at weekly intervals from 36-40 wk gestation. The levels of both hPL and E3 were reduced in subjects delivering a growth-retarded child. The clinical significance of this observation was similar for the two compounds, with a marginal advantage to hPL. There was a higher incidence of falling levels of hPL and E3 in cases of growth retardation but the finding had very little predictive value in an individual patient.

Adult↗
PubMed1985

Maternal and fetal alphafetoprotein (AFP) levels at term. Relation to sex, weight and gestation of the infant.

Serum alpha-fetoprotein (AFP) was measured in maternal, cord arterial and venous blood. Samples were collected at the time of vaginal delivery from 105 women at 36-42 weeks' gestation. There was a significant correlation between maternal, cord arterial and venous AFP. Umbilical cord arterial and venous AFP levels were considerably higher in male infants than in females. Umbilical AFP levels declined with lengthening gestation and increasing birthweight for both male and female infants and a similar pattern was seen in the mother. Fetal AFP levels were significantly higher in subjects giving birth at 40 weeks whose infants had a birthweight below the population mean vis-à-vis those above the mean. It is concluded that the absolute size of the fetus as well as gestational age may play a significant role in determining maternal and fetal AFP concentration.

Birth Weight↗
PubMed1984

Human placental lactogen in pre-eclampsia.

Serum placental lactogen (hPL) was measured in serial blood samples obtained from 663 pregnant women at weekly intervals from 36 to 40 weeks. The group included 231 women with pre-eclampsia. Levels of hPL were significantly elevated in primigravidae with this condition but not in multigravidae. In all groups hPL levels were significantly reduced in association with growth retardation, but the clinical value of this observation appeared to be greater in multigravidae than in primigravidae. It is suggested that in primigravidae with pre-eclampsia maternal hPL levels reflect both the pathology of the disease as well as the condition of the fetus.

Birth Weight↗
PubMed1983

Maternal blood levels of human placental lactogen in the prediction of fetal growth retardation: choosing a cut-off point between normal and abnormal.

Single estimations of serum human placental lactogen (hPL) were made in 527 unselected women between 36 and 40 weeks gestation. The association between decreased serum levels of hPL and intrauterine growth retardation was confirmed. The effect of changing the cut-off point between normality and abnormality on the sensitivity, specificity and predictive value was determined. When the 10th centile of hPL values was used, 29% of all growth-retarded fetuses were identified and 91% of all 'normal' fetuses were excluded. The 15th and 25th centiles yielded improved sensitivities of 37 and 50% respectively, but specificity was reduced. It is suggested that the 10th centile provides a good compromise between sensitivity on the one hand and specificity and predictive value on the other.

Female↗
PubMed1982

Placental protein 5: disappearance from the circulation after delivery.

Blood was collected from 8 women following delivery at term. The decline in serum concentrations of placental protein 5 following the delivery of the infant's head was studied for 12 h. Placental protein 5 levels fell very rapidly with a half-life of 5-39 min. In the majority of women placental protein 5 was undetectable after 12 h (i.e. less than 2 microgram/l).

Adult↗
PubMed1982

What do placental function tests predict? Observations on placental lactogen levels in growth retardation and fetal distress.

Single blood samples were obtained from an unselected population of 527 women between 36 and 40 wk gestation. Serum placental lactogen levels were lower than normal in patients whose infants were growth retarded or developed fetal distress in labor. These associations were independent; the fetal distress group did not contain an excess of subjects with growth retardation. Thus, the results of a biochemical test reflect dynamic aspects of placental function and not simply the overall growth of fetus and placenta.

Female↗
PubMed1982

Human chorionic gonadotropin levels in maternal blood in late pregnancy: relation to birthweight, sex and condition of the infant at birth.

A total of 527 blood samples was obtained from an unselected population of women between 36 and 40 weeks gestation. Serum human chorionic gonadotropin (hCG) levels were measured using a specific radioimmunoassay for the beta 1-subunit of hCG. Serum hCG levels were higher in primigravidae and in women carrying female fetuses. They were also related to the birthweight of the child and to the occurrence of fetal distress.

Birth Weight↗
PubMed1981

Placental protein 5: circulating levels in twin pregnancy and some observations on the analysis of biochemical data from multiple pregnancy.

Blood was collected from 344 subjects with singleton pregnancy between 28 and 40 wk gestation, together with 70 samples from 24 subjects with twin pregnancy of comparable gestation. Circulating placental protein 5 (PP5) in singleton pregnancy rose from a median of 26 microgram/l at 28 wk to reach a plateau with a median of 38 microgram/l at 36 wk. The median PP5 levels in twin pregnancy were 50 microgram/l at 28 wk rising to 65 microgram/l at 38 wk. The ratio of the medians of PP5 levels in twin and singleton pregnancies fell from 1.94 at 28 wk to 1.62 at 38 wk. An "action line' for low levels of PP5 in twin pregnancy was defined by applying a multiple of the median for twin pregnancy.

Analysis of Variance↗
PubMed1980

Molecular heterogeneity of placental protein 5 (PP5) in late pregnancy serum and plasma: evidence for a heparin-PP5 polymer.

The apparent levels of placental protein 5 (PP5) measured by radioimmunoassay are substantially greater in serum than plasma. Using molecular sieve chromatography we have shown that PP5 exists in a number of different forms, and that in the presence of heparin or endogenous heparin-like substances PP5 forms complexes and polymers. These findings add weight to the concept that PP5 may be involved with the coagulation system and, in particular, with coagulation mechanisms in the intervillous space of the human placenta.

Chromatography, Gel↗
PubMed1980

Circulating levels of placental protein 5 in the mother: relation to birth weight.

A total of 914 blood samples was obtained from an unselected population of 400 women between 36 and 40 weeks gestation. Serum PP5 levels were measured by a sensitive radioimmunoassay. After ranking of PP5 levels and birth weight the value of serum PP5 in the diagnosis of intrauterine growth retardation was examined. The sensitivity, predictive value, and specificity of the test were 17.07, 16.66, and 90.25 per cent respectively; these results suggest that serum PP5 levels are less accurate than other biochemical parameters in the identification of fetal growth retardation in late pregnancy.

Birth Weight↗
PubMed1979

Placental protein 5 in fetal and maternal compartments.

Placental protein 5 is produced by the syncytiotrophoblast and secreted into the maternal peripheral circulation reaching levels of approximately 30 micrograms per litre in normal pregnancy at term. In the present study the distribution of PP5 was examined in maternal and fetal compartments in 13 patients at delivery.

Amniotic Fluid↗
PubMed1979

Circulating levels of pregnancy specific beta 1 glycoprotein in late pregnancy: nyctohemeral and day-to-day variation, and variation during labour.

Circulating levels of pregnancy-specific beta 1 glycoprotein have been determined in a number of physiological situations in late pregnancy. The apparent variation in five subjects studied over a 24-hour period was not in excess of that due to the assay. Excess variation was apparent in 2 of 11 subjects studied daily for up to 8 days, and in 6 of 16 patients studied serially during labour.

Circadian Rhythm↗
PubMedDate not supplied

Relationship of maternal and fetal levels of human placental lactogen to the weight and sex of the fetus.

In a study of 101 patients at term, the maternal and umbilical cord artery and vein levels of human placental lactogen (hPL) were correlated against the sex and birthweight of the fetus. No difference in hPL levels was found between cord artery and vein. The maternal hPL level correlated well with the delivered weight of the child, but no relationship could be demonstrated in the case of umbilical cord blood. Pregnancies with a female child had a higher level of hPL, which was significant only in cord samples.

Birth Weight↗