The relation of uteroplacental and umbilical Doppler resistance index (RI) to peripheral levels of alphafetoprotein (AFP), human chorionic gonadotrophin (hCG), human placental lactogen (HPL), Schwangerswaft protein (SP1), pregnancy-associated placental protein A (PAPP-A) and insulin-like growth factor binding protein 1 (IGP-BP1) at 16-24 weeks was established in a cross-sectional study of 183 unselected singleton pregnancies. There was an association between high values of uteroplacental RI and high hCG levels, and high umbilical RI values with high hCG and HPL levels. Thus, in the mid-trimester, the levels of some placental proteins seem to be related to placental resistance.

Carrier Proteins↗

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The ratio between molecular variants of pregnancy-specific beta 1 glycoprotein (SP1) in the peripheral and retroplacental circulation during later pregnancy.

The ratio between two molecular variants of pregnancy-specific beta 1 glycoprotein (SP1) in the peripheral and retroplacental circulation was analysed in nine women during late pregnancy. The ratio between the two molecular variants, i.e. SP1 beta and SP1 alpha, was found to be identical in the peripheral and retroplacental circulation in all women examined. Comparisons were also made between SP1 beta as measured by radioimmunoassay and a normal serum protein, alpha 2 macroglobulin. A positive concentration gradient from peripheral to retroplacental circulation was found for SP1 beta whereas the gradient was less pronounced for alpha 2 macroglobulin. These findings add weight to the concept that SP1 alpha is a unique molecular species and not a genetic variant or a product of SP1 beta.

Female↗

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The effect of thrombin on serum placental protein 5 (PP5): is PP5 the naturally occurring antithrombin III of the human placenta?

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Antithrombin III↗

PubMedDate not supplied

Immunohistochemical demonstration of placental protein 5 in trophoblastic tumours.

An immunoperoxidase technique was used for the detection of placental protein 5 (PP5) in tissue specimens from trophoblastic tumours. PP5 was detected in all of 15 cases of hydatidiform mole, in two out of six destructive moles and in one of seven choriocarcinomas. Though the biological importance of PP5 is not clear, its association with inactivation of plasmin suggests a role in the control of placental invasiveness.

Female↗

PubMedDate not supplied

Human seminal plasma contains a wide range of trophoblast-'specific' proteins.

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Chorionic Gonadotropin↗

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↗

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The relationship of placental protein 14 (PP14) in the mother and fetus to specific products of the human placenta.

Levels of placental protein 14 (PP14), human placental lactogen (hPL) and unconjugated oestriol (E3) were measured in maternal peripheral and umbilical arterial and venous blood obtained from 65 normal pregnancies at term delivery. PP14 levels were one order of magnitude higher in the mother than in the fetus. Neither maternal nor fetal levels of PP14 were related to the birthweight of the fetus. There was a relationship between maternal and umbilical venous levels of PP14, which suggests that fetal PP14 is derived by transfer from the mother, or that there is an independent fetal source with a control mechanism similar to that of the mother. The findings are compatible with earlier observations to the effect that PP14, in contrast to products such as hPL and E3, is not specific to the trophoblast.

Birth Weight↗

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Cytokines in implantation.

Implantation is a complex process which involves the 'invasion' of the maternal endometrium by the trophoblast surrounding the developing blastocyst. In response to this interaction there is a cellular reaction within the endometrium which has some features analogous to invasion by a tumour and some which are more characteristic of an inflammatory response. In addition, and also in common with cancer and inflammation, there is a release of biologically active molecules, including cytokines, at and around the implantation site. The information on cytokines is complex and often contradictory but it is recognised that they play an important role in the successful establishment of pregnancy. The evidence for this role is examined in this review.

Animals↗

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Evaluation of a fetal risk-scoring system.

A population of 2029 pregnant women (929 primiparas; 1100 multiparas) has been used to examine aspects of the calculation of obstetric risk scores from the presence of individual risk factors. The findings have been related to fetal outcome in these pregnancies and the following conclusions were reached: (1) the use of Bayes theorem for the calculation of a risk score is superior to the simple addition of weighted risk factors; (2) the diagnostic efficiency of a risk score is somewhat reduced when the data base used for calculation of the score is derived from a population different from that of the current pregnancy; (3) there is almost total overlap of risk scores in women with satisfactory and unsatisfactory fetal outcome. It is concluded that risk scores can be used to identify a small group of women at particularly high risk; in the remainder of the population scores are unhelpful except perhaps to indicate the women who do not require an intensive program of antenatal care.

Bayes Theorem↗

PubMedDate not supplied

Qualitative probability versus quantitative probability in clinical diagnosis: a study using a computer simulation.

The use of Bayes' theorem as a diagnostic tool in clinical medicine normally requires an input of exact probability estimates. However, humans tend to think in categories ("likely," "unlikely," etc.) rather than in terms of exact probability. A computer simulation of the presenting features of a case of pelvic infection has been used to compare the effects of quantitative and qualitative probability estimates on the diagnostic accuracy of Bayes' theorem. For the commoner conditions (prior probability greater than or equal to 0.2) the use of a two- or three-category system is virtually equivalent to the use of exact probability. However, uncommon conditions (prior probability less than or equal to 0.03) are completely ignored by the qualitative system. It is concluded that the use of simple categories of probability is acceptable for a Bayesian diagnostic system provided that the target conditions have a relatively high prior probability.

Artificial Intelligence↗