Diagnostic accuracy of placental growth factor and ultrasound parameters to predict the small-for-gestational-age infant in women presenting with reduced symphysis-fundus height.

OBJECTIVES: To assess the diagnostic accuracy of placental growth factor (PlGF) and ultrasound parameters to predict delivery of a small-for-gestational-age (SGA) infant in women presenting with reduced symphysis-fundus height (SFH). METHODS: This was a multicenter prospective observational study recruiting 601 women with a singleton pregnancy and reduced SFH between 24 and 37 weeks' gestation across 11 sites in the UK and Canada. Plasma PlGF concentration < 5(th) centile, estimated fetal weight (EFW) < 10(th) centile, umbilical artery Doppler pulsatility index > 95(th) centile and oligohydramnios (amniotic fluid index < 5 cm) were compared as predictors for a SGA infant < 3(rd) customized birth-weight centile and adverse perinatal outcome. Test performance statistics were calculated for all parameters in isolation and in combination. RESULTS: Of the 601 women recruited, 592 were analyzed. For predicting delivery of SGA < 3(rd) centile (n = 78), EFW < 10(th) centile had 58% sensitivity (95% CI, 46-69%) and 93% negative predictive value (NPV) (95% CI, 90-95%), PlGF had 37% sensitivity (95% CI, 27-49%) and 90% NPV (95% CI, 87-93%); in combination, PlGF and EFW < 10(th) centile had 69% sensitivity (95% CI, 55-81%) and 93% NPV (95% CI, 89-96%). The equivalent receiver-operating characteristics (ROC) curve areas were 0.79 (95% CI, 0.74-0.84) for EFW < 10(th) centile, 0.70 (95% CI, 0.63-0.77) for low PlGF and 0.82 (95% CI, 0.77-0.86) in combination. CONCLUSIONS: For women presenting with reduced SFH, ultrasound parameters had modest test performance for predicting delivery of SGA < 3(rd) centile. PlGF performed no better than EFW < 10(th) centile in determining delivery of a SGA infant.

Low pregnancy associated plasma protein-A in the 1st trimester: is it a predictor of poor perinatal outcome?

The objective of the study was to examine the predictive value of pregnancy associated plasma protein-A (PAPP-A) as a marker of poor pregnancy outcome. Databases at the University Hospital Lewisham, were used retrospectively to identify singleton pregnancies, which underwent 1st trimester combined screening between July 2008 and April 2010 and were found to have PAPP-A levels ≤ 0.4 MoM. The perinatal courses of these pregnancies (n = 315) were evaluated for signs of adverse perinatal outcome and compared with a matched control group of pregnancies (n = 330) with normal PAPP-A levels. Results showed that women with low serum PAPP-A were at increased risk of adverse pregnancy outcome compared with the control group (OR 2.4, p = 000.1). They were also more likely to suffer fetal loss (OR 6.2, p = 0.001) in the form of miscarriage (OR 2.7, p = 0.110) and stillbirth (OR 2.4, p = 0.001). It was concluded that serum PAPP-A is a marker for poor pregnancy outcome and women with low serum PAPP-A levels would benefit from increased monitoring of their pregnancies.

A review of the EXIT (Ex utero Intrapartum Treatment) procedure.

The EXIT (Ex utero Intrapartum Treatment) procedure is done in cases where difficulty is anticipated in neonatal airway establishment at delivery and is done at the time of caesarean section. The partially delivered fetus is maintained on placental circulation while airway is established and this is carried out by a multidisciplinary team. In this paper, we review the indications, the maternal and fetal considerations of the procedure and the results and outcomes. The review highlights the fact that the benefits far outweigh the risks and that the risk of postpartum haemorrhage is more theoretical than real. As technology improves and more anomalies are diagnosed during the antenatal period, the EXIT procedure can be performed with good results after carefully considering the ethical issues. We have performed a MEDLINE search by using the keywords EXIT, CHAOS, fetal surgery, fetal neck masses and ex utero intrapartum treatment. As there are not many large studies, we have also reviewed smaller case series and case reports.

Antenatal detection of arteriovenous anastomoses in monochorionic twin pregnancy.

OBJECTIVES: To revalidate the detection technique for arteriovenous anastomoses in an unselected group of monochorionic twins, and to make recommendations about its applicability for more widespread use. METHODS: Women with monochorionic diamniotic (MCDA) twins were recruited and underwent placental mapping by color Doppler ultrasound. Images of placental maps showing the location and type of anastomoses were saved as digital video clips. After delivery, dye injection study of all the placentas was performed to delineate the site and type of anastomoses. A digital photograph of each injection study was taken and saved. The antenatal ultrasound images and postnatal dye injection studies were compared. RESULTS: 18 sets MCDA twins were evaluated. In 3 cases there was evidence of twin-to-twin transfusion syndrome. Dye injection of 18 placentas revealed 21 arterio-arterial anastomoses (AAA), 21 arteriovenous anastomoses (AVA) and 4 veno-venous anastomoses (VVA). Of these, 10 (48%) AAAs and 5 (24%) AVAs were detected antenatally by color Doppler. In all cases, where an AVA was detected, the placenta was located anteriorly. CONCLUSION: Antenatal detection of AVA was feasible when the placenta was located anteriorly, but proved difficult in posteriorly situated placentas.

Steady state and picosecond time-resolved fluorescence studies on native, desulpho and deflavo xanthine oxidase.

Steady state and time-resolved fluorescence studies on native, desulpho and deflavo xanthine oxidase (XO) have been carried out to investigate the conformational changes associated with the replacement of the molybdenum double bonded sulphur by oxygen and the removal of the flavin adenine dinucleotide (FAD). The steady state quenching experiments of the intrinsic tryptophan residues of the enzyme show that all the nine tryptophans are accessible to neutral quencher, acrylamide, in the native as well as desulpho and deflavo enzymes. However, the number of the tryptophan residues accessible to the ionic quenchers, potassium iodide and cesium chloride, increases upon removal of the FAD centre from the enzyme. This indicates that two tryptophan residues move out from the core of the enzyme to the solvent upon the removal of the FAD. The time-resolved fluorescence studies were carried out on the native, desulpho and deflavo XO by means of the time-correlated single photon counting technique, and the data were analysed by discrete exponential and maximum entropy methods. The results show that the fluorescence decay curve fitted best to a three-exponential model with lifetimes tau(1)=0.4, tau(2)=1.4 and tau(3)=3.0 ns for the native and desulpho XO, and tau(1)=0.7, tau(2)=1.7 and tau(3)=4.8 ns for the deflavo XO. The replacement of the molybdenum double bonded sulphur by oxygen in the desulpho enzyme does not cause any significant change of the lifetime components. However, removal of the FAD centre causes a significant change in the shortest and longest lifetime components indicating a conformational change in the deflavo XO possibly in the flavin domain. Decay-associated emission spectra at various emission wavelengths have been used to determine the origin of the lifetimes. The results show that tau(1) and tau(3) of the native and desulpho XO originate from the tryptophan residues which are completely or partially accessible to the solvent but tau(2) corresponds to those residues which are buried in the core of the enzyme and not exposed to the solvent. For deflavo enzyme, tau(2) is red shifted compared to the native enzyme indicating the movement of tryptophan residues from the core of the enzyme to the solvents.

Interaction of Cu2+ ion with milk xanthine oxidase.

The interaction of Cu2+ ion with milk xanthine oxidase (XO) has been studied by optical spectroscopy, circular dichroism, ESR and transient kinetic techniques. It is observed that XO forms optically observable complexes with Cu2+ ion. The pH dependence studies of the formation of Cu2+-XO complex by optical spectroscopy and circular dichroism show that at least one ionizable group may be responsible for the formation of the complex. The EPR studies show that Cu2+ ion binds to XO with sulfur and nitrogenous ligands. The transient kinetic study of the interaction of Cu2+ with XO shows the existence of two Cu2+ bound XO complexes formed at two different time scales of the interaction, one at < or =5 ms and the other one at around 20 s. The complex formed at longer time scale may be responsible for the inhibition of the enzyme activity.

Mechanism of the inhibition of milk xanthine oxidase activity by metal ions: a transient kinetic study.

The nature and mechanism of the inhibition of the oxidoreductase activity of milk xanthine oxidase (XO) by Cu(2+), Hg(2+) and Ag(+) ions has been studied by steady state and stopped flow transient kinetic measurements. The results show that the nature of the inhibition is noncompetitive. The inhibition constants for Cu(2+) and Hg(2+) are in the micromolar and that for Ag(+) is in the nanomolar range. This suggests that the metal ions have strong affinity towards XO. pH dependence studies of the inhibition indicate that at least two ionisable groups of XO are involved in the binding of these metal ions. The effect of the interaction of the metal ions on the reductive and oxidative half reactions of XO has been investigated, and it is observed that the kinetic parameters of the reductive half reaction are not affected by these metal ions. However, the interaction of these metal ions with XO significantly affects the kinetic parameters of the oxidative half reaction. It is suggested that this may be the main cause for the inhibition of XO activity by the metal ions.

Evidence for A+(anti)-G(syn) mismatched base-pairing in d-GGTAAGCGTACC.

Two-dimensional NMR spectroscopy has been used to study the structure and hydrogen bonding scheme of A:G mismatched base pairing in d-GGTAAGCGTACC at pH 5.8. Under the conditions of our study, the molecule forms a B-DNA helix, with the mismatched bases in the A+ anti)-G(syn) conformation. The adenosine exists in the protonated form. The NOESY spectrum in 90% H2O + 10% 2H2O has been used to assign all observable imino and amino protons including those involved in the A+(anti)-G(syn) base pair. Both the proton donors in the A:G mismatched inter-base hydrogen bonding are situated on adenosine.

Spanwise bifurcation in plane-symmetric sudden-expansion flows.

Present computational investigation reports a steady bifurcation phenomenon for three-dimensional flows through a plane-symmetric sudden expansion. When the channel aspect ratio exceeds a critical value, the well-known step height (pitchfork) bifurcation evolves with different symmetry breaking orientations on the left and right sides of the channel and bifurcates in the spanwise direction. For the channel aspect ratio less than the critical value, the originally occurring spanwise bifurcation cannot be stably retained and evolves eventually to a step height bifurcation. Compared to step height bifurcation, the spanwise bifurcation is found to be more difficult to obtain, because the symmetric flow present on the spanwise symmetry plane is unstable in two dimensions. For completeness, an extensive analysis of the observed spanwise bifurcation, covering its transient behavior, dependence on flow Reynolds number, channel aspect ratio, and expansion ratio, is included.

Azathioprine and breastfeeding: is it safe?

Traditionally, women receiving azathioprine have been discouraged from breastfeeding because of theoretical potential risks of neonatal bone marrow suppression, susceptibility to infection, and pancreatitis. The aims of this study were to measure the concentration of 6-mercaptopurine (6-MP) in breast milk of mothers receiving azathioprine and in the blood of their babies and to investigate any immunosuppressive effects on the babies. Women receiving azathioprine, who after appropriate counselling wished to breastfeed their babies, were approached for inclusion in the study. Breast milk samples were obtained from recruited women, and 6-MP levels were measured in each breast milk sample. Haemoglobin level, white cell and platelet counts, and 6-MP and 6-thioguanine nucleotides (6-TGN) levels were measured in the respective neonatal blood samples. Clinical signs of immunosuppression in the neonates were noted. Thirty-one breast milk samples were collected from ten women. Low concentrations of 6-MP (1.2 and 7.6 nanograms/ml, compared with therapeutic immunosuppressant level of 50 nanograms/ml in serum) were detected in two breast milk samples obtained from one woman. 6-MP was not detected in any of the other 29 samples. 6-MP and 6-TGN were undetectable in the neonatal blood. There were no clinical or haematological signs of immunosuppression in any of the ten neonates. We conclude that breastfeeding should not be withheld in infants of mothers receiving azathioprine.

Vaginal delivery can be considered in monochorionic diamniotic twins.

The outcomes of 60 sets of monochorionic diamniotic (MCDA) twins were compared with 218 sets of dichorionic diamniotic (DCDA) twins. The caesarean section rates for MCDA were similar to those for DCDA twins (56.6 versus 53.6%, P > 0.1). Although the number of babies with 5-minute Apgar score of <7 was significantly higher for vaginally delivered MCDA twins compared with that of DCDA twins (12 versus 3.5%, P < 0.001), the umbilical artery pH of <7.2 was similar (20 versus 13%, P > 0.05). Admission to neonatal intensive care unit (NICU) and neonatal mortality were also similar in both groups. Delivery by caesarean section was associated with increased admission to the NICU and neonatal mortality for MCDA twins when compared with vaginal delivery group. From this retrospective cohort study, we can conclude that vaginal delivery for MCDA twins appeared to be a reasonable management option when similar selection criteria for vaginal delivery of DCDA twins were applied.

Intraobserver and interobserver variation in the sonographic grading of placental maturity.

OBJECTIVES: The appearance of Grannum Grade III changes in the placenta at around 34-36 weeks is a predictor of adverse perinatal outcome, which may be reduced by reporting to the clinician. This has led to the suggestion that the placental grade should be noted during any third-trimester scan. There are no published data on the reproducibility of sonographic Grannum grading of the placenta; the objective of this study was to evaluate intra- and interobserver variation. METHODS: Fifty-five placental images from normal and complicated pregnancies of several different gestational ages were collected between April and October 2001. Three fetal medicine consultants and three experienced sonographers graded the images as 0, I, II, III or ungradeable. They then regraded the same images, presented in a different order and with different codes, 4-6 weeks later. Observers were blinded to their previous grading and to each others'. Weighted kappa (kappa), with linear weights, was used to look for strength of agreement. RESULTS: There was good agreement between the two observations of each placental image for five observers (kappa = 0.61 to 0.90), and moderate agreement for one observer (kappa = 0.56). However, the kappa-values for comparisons between the 15 pairs of observers ranged from 0.24 to 0.69 with six values below 0.41, indicating only fair agreement. This was confirmed by the overall kappa-value of 0.24 between all six observers. The agreement between the observers for Grade III placenta was poor, with an overall kappa-value of 0.09. CONCLUSIONS: Although intraobserver agreement was generally good, interobserver agreement was only fair for all grades and poor for Grade III placenta. This may be an indication that Grannum grading is not reproducible or it may reflect a need for training in those performing grading. Such variation may limit the effectiveness of reporting Grannum grades in clinical practice.

Nonobstetric lower genital tract trauma.

In a 4-year-period there were 31 admissions to Nehru Hospital, because of nonobstetric injuries of the female genital tract. This constituted 0.8% of all gynaecological admissions over this period. The injuries were caused by voluntary coitus, automobile accidents and various types of astride injuries. Seven of the 18 patients with noncoital injuries presented with vulval haematomas and all were managed by evacuation under general anaesthesia. Two of the 13 patients with coital injury were admitted with haemorrhagic shock and required initial resuscitation with blood transfusion. The vaginal vault, especially the right and posterior fornices were the frequent sites of coital injury for parous women; on the other hand lower vaginal and introital injuries were caused by first acts of coitus. Except for trivial superficial lacerations with minimal bleeding, primary definitive surgical repair other than vaginal packing was favoured for better healing and to reduce morbidity.

Screening for trisomy 21: the significance of a positive second trimester serum screen in women screen negative after a nuchal translucency scan.

Screening of pregnancies for trisomy 21 is now an accepted part of antenatal care. Measurement of fetal nuchal translucency in the first trimester and analysis of maternal serum biochemistry in the second trimester are both established methods of screening. The performance characteristics of both tests in an unselected population are well described and the choice of test offered is usually determined by local policy and resources. We present data from a screening programme offering women with a low risk result from nuchal translucency measurement a second trimester serum screen. There were eight cases of trisomy 21 in the 2683 women screened, all of which presented with a high-risk nuchal screen result. Serum screening of 1057 women who screened negative by nuchal translucency gave 46 high-risk results, all of which were, therefore, false positive for trisomy 21. Second trimester biochemistry screening following a negative nuchal translucency screen did not increase the detection of trisomy 21.

Steady-state and time-resolved fluorescence studies on wild type and mutant chromatium vinosum high potential iron proteins: holo- and apo-forms.

Detailed circular dichroism (CD), steady-state and time-resolved tryptophan fluorescence studies on the holo- and apo- forms of high potential iron protein (HiPIP) from Chromatium vinosum and its mutant protein have been carried out to investigate conformational properties of the protein. CD studies showed that the protein does not have any significant secondary structure elements in the holo- or apo- HiPIP, indicating that the metal cluster does not have any effect on formation of secondary structure in the protein. Steady-state fluorescence quenching studies however, suggested that removal of the iron-sulfur ([Fe(4)S(4)](3+)) cluster from the protein leads to an increase in the solvent accessibility of tryptophans, indicating change in the tertiary structure of the protein. CD studies on the holo- and apo- HiPIP also showed that removal of the metal prosthetic group drastically affects the tertiary structure of the protein. Time-resolved fluorescence decay of the wild type protein was fitted to a four-exponentials model and that of the W80N mutant was fitted to a three-exponentials model. The time-resolved fluorescence decay was also analyzed by maximum entropy method (MEM). The results of the MEM analysis agreed with those obtained from discrete exponentials model analysis. Studies on the wild type and mutants helped to assign the fast picosecond lifetime component to the W80 residue, which exhibits fast fluorescence energy transfer to the [Fe(4)S(4)](3+) cluster of the protein. Decay-associated fluorescence spectra of each tryptophan residues were calculated from the time-resolved fluorescence results at different emission wavelengths. The results suggested that W80 is in the hydrophobic core of the protein, but W60 and W76 are partially or completely exposed to the solvent.

Induction of labour in pregnancy complicated by cardiac disease.

Twenty one pregnant patients with cardiac disease had induction of labour for various obstetric reasons with a modified oxytocin infusion method. All of them went into labour and delivered within 20 hours. Twenty patients delivered vaginally. Three neonates had birth asphyxia (Apgar score < 7) and 1 of them died on the 4th day from prematurity. No adverse effect of oxytocin infusion on maternal cardiac status was observed and all of the women went home in good condition. Induction of labour with a modified oxytocin infusion is a safe and effective alternative for selected gravidas with cardiac disease where elective delivery is warranted.

Biochemical and kinetic analysis of the RNase active sites of the integrase/tyrosine family site-specific DNA recombinases.

In this study, we have used multiple strategies to characterize the mechanisms of the type I and type II RNA cleavage activities harbored by the Flp (pronounced here as "flip") site-specific DNA recombinase (Flp-RNase I and II, respectively). Reactions using half-sites pre-bound by step-arrest mutants of Flp agree with a "shared active site" being responsible for the type I reaction (as is the case with normal DNA recombination). In a "pre-cleaved" type I substrate containing a 3'-phosphotyrosyl bond, the Flp-RNase I activity can be elicited by either wild type Flp or by Flp(Y343F). Kinetic analyses of the type I reaction are consistent with the above observations and support the notion that the DNA recombinase and type I RNase active sites are identical. The type II RNase activity is expressed by Flp(Y343F) in a half-site substrate and is unaffected by the catalytic constitution of a Flp monomer present on a partner half-site. Reaction conditions that proscribe the assembly of a DNA bound Flp dimer have no effect on Flp-RNase II. These biochemical results, together with kinetic data, are consistent with the reaction being performed from a "non-shared active site" contained within a single Flp monomer. The Flp-related recombinase Cre, which utilizes a non-shared recombination active site, exhibits the type I RNA cleavage reaction. So far, we have failed to detect the type II RNase activity in Cre. Despite their differences in active site assembly, Cre functionally mimics Flp in being able to provide two functional active sites from a trimer of Cre bound to a three-armed (Y-shaped) substrate.