The demonstration of two pregnancy-associated proteins with SP1 determinants in placental extracts.

The SP1 content of the placenta has been examined. It was found that, as in pregnancy serum, two variants of the protein existed in the placenta. The smaller molecule, with a beta 1 electrophoretic mobility, is readily extractable with phosphate buffered saline. The second larger molecule is more tightly bound in the placenta and requires Triton X-100 to be solubilized. The hypothesis is put forward that the larger alpha variant is the precursor form which is related more irregularly and in a smaller amount from the placenta into the maternal circulation.

The composition and concentration of umbilical cord plasma lipoproteins; their relationship to the birth weight and other clinical factors of the newborn.

The present studies confirmed that plasma obtained from individual umbilical cords contains very low density, low density and high density lipoprotein particles whose mean compositions are similar to those of the adult, though they are present in considerably lower concentrations. A fairly wide variation in both composition and concentration was found between different individuals. For full-term deliveries, a positive correlation (p less than 0.01) was found between the cholesteryl ester: free cholesterol ratio of the high density lipoprotein fraction and the birth weight, suggesting differences in the distribution of the particles that constitute this lipoprotein fraction. Otherwise, no correlation was found between the composition or concentration of any lipoprotein fraction and birth weight, gestation, sex or other factor investigated. Premature newborns (30-36 weeks) had concentrations of high density lipoproteins and cholesteryl ester: free cholesterol ratios of the high density lipoprotein that were markedly high in relation to their birth weights and in the same range as full-term newborns (37-40 weeks).

Effect of anticoagulants on the measurement of pregnancy-associated plasma protein-A (PAPP-A).

The level of pregnancy-associated plasma protein-A (PAPP-A) in blood measured by rocket immunoelectrophoresis is affected by the addition of anticoagulants. When compared with levels in serum, those in heparin and sequestrene plasmas were higher, while those in sodium citrate, acid citrate dextrose and fluoride oxalate plasmas were lower. Similar results were obtained when the anticoagulants were added to serum and the effect on the measured level was dose-dependent within limits. Addition of anticoagulants to serum affected the mobility of PAPP-A in crossed immunoelectrophoresis, but this was not necessarily in keeping with the effect on rocket height. Addition of sodium chloride to serum did not influence the measured levels of PAPP-A.