The diminished effect of index rebalances

The author revisits the strategy of trading S&P 500 index re-compositions under the pre- and post-crisis financial environments, proving that the return structure has significantly changed. The results show for the first time, that there are currently no tradable abnormal returns between announcement and event dates in the post-crisis sample period, indicating smoother rebalancing mechanisms by bank’s client facing desks and better services for passive end-investors. The newly added firms inflate the S&P 500 index by less than 10 basis points per year. The results could be attributed to improved execution algorithms used by the banks, and potentially to the new regulatory reforms in the sector, which prevents financial institutions from taking large trading positions with their balance sheets

Lack of replication of higher genetic risk load in men than in women with systemic lupus erythematosus

Introduction: We aimed to replicate a recent study which showed higher genetic risk load at 15 loci in men than in women with systemic lupus erythematosus (SLE). This difference was very significant, and it was interpreted as indicating that men require more genetic susceptibility than women to develop SLE. Methods: Nineteen SLE-associated loci (thirteen of which are shared with the previous study) were analyzed in 1,457 SLE patients and 1,728 healthy controls of European ancestry. Genetic risk load was calculated as sex-specific sum genetic risk scores (GRS(s)). Results: Our results did not replicate those of the previous study at either the level of individual loci or the global level of GRS(s). GRS(s) were larger in women than in men (4.20 ± 1.07 in women vs. 3.27 ± 0.98 in men). This very significant difference (P < 10(-16)) was more dependent on the six new loci not included in the previous study (59% of the difference) than on the thirteen loci that are shared (the remaining 41%). However, the 13 shared loci also showed a higher genetic risk load in women than in men in our study (P = 6.6 × 10(-7)), suggesting that heterogeneity of participants, in addition to different loci, contributed to the opposite results. Conclusion: Our results show the lack of a clear trend toward higher genetic risk in one of the sexes for the analyzed SLE loci. They also highlight several limitations of assessments of genetic risk load, including the possibility of ascertainment bias with loci discovered in studies that have included mainly women

Noninvasive prenatal diagnosis of Down syndrome: Current knowledge and novel insights

The noninvasive prenatal diagnosis of trisomy 21 (Down syndrome) is an actively researched area of prenatal medicine, as this is the most common aneuploidy compatible with life and a major cause of mental retardation. The isolation of intact fetal cells, and most importantly, the successful detection of fetalorigin nucleic acids (cell-free fetal DNA and RNA), in maternal plasma even from the early stages of pregnancy has inspired scientists to develop discriminative genetic markers for the prenatal detection of aneuploidy. In the near future, the development of epigenetic fetal-specific markers will possibly allow the universal application of a cell-free fetal DNA-based diagnostic test regardless of the gender of the fetus or its polymorphic status. Other promising approaches rely upon the detection of free placentally derived RNA transcribed from genes located on chromosome 21 and the application of highly sensitive techniques, such as digital polymerase chain reaction and high-throughput shotgun sequencing. However, irrespective of which strategy is selected for isolating or distinguishing fetal genetic material in maternal plasma, the small quantity of fetal origin nucleic acids poses severe technical challenges. In this review article, we present an overview of the current knowledge in the field of noninvasive prenatal assessment of fetuses with Down syndrome and the future perspectives regarding new fetal markers and novel molecular techniques that may eventually be applied in the clinical setting as a valid and safe option for women who opt for noninvasive accurate prenatal diagnosis. Copyright © by Walter de Gruyter · Berlin · Boston

Role of the angiopoietin/Tie system in pregnancy (Review)

Angiopoietin-1 and - 2 are endogenous ligands for the vascular endothelium-specific receptor tyrosine kinase Tie-2. The angiopoietin/Tie system plays a critical role in the regulation of endothelial cell survival and vascular maturation and stability. Apart from its well-established role in vascular morphogenesis, emerging data support the involvement of angiopoietins in inflammation and various malignancies. Previous studies have underlined the significance of several angiogenic factors in normal placental development. In addition, angiogenic imbalance is observed in pregnancy complications related to impaired placentation, such as preeclampsia (PE) and intrauterine growth restriction (IUGR). However, there is only limited information available on the role of the angiopoietin/Tie system in the establishment of a competent feto-maternal vascular system. In this review, we present the current knowledge regarding the role of angiopoietins in normal pregnancy and pregnancy complications. © 2015, Spandidos Publications. All rights reserved

Placental volume at 11 to 14 gestational weeks in pregnancies complicated with fetal growth restriction and preeclampsia

Objective: The study aims to evaluate the predictive value of first trimester placental volume in pregnancies destined to develop fetal growth restriction (FGR) and preeclampsia (PE). Methods: Prospective observational study including placentas from 34 FGR, 12 PE, 15 GH (gestational hypertension) pregnancies, and 265 controls. Placental volume (PV) was obtained using VOCAL technique, and a z score was calculated (z-PV). The association of PV with other first trimester variables and maternal characteristics was assessed with Spearman&apos;s correlation. Results: PV increased exponentially with crown-rump length (CRL) and was unrelated to maternal factors (weight, age, parity, and smoking status) as well as first trimester uterine artery Doppler, free β-hCG, nuchal translucency, or fetal heart rate. However, PV was positively associated with maternal height, CRL, PAPP-A, and birth weight. z-PV was a strong predictor for FGR with abnormal fetal Dopplers (AUC = 0.9472, P &lt; 0.001). z-PV provided moderate prediction of FGR with normal fetal Dopplers (AUC = 0.8396, P &lt; 0.001), PE (AUC = 0.8312, P &lt; 0.001), and GH (AUC = 0.7640, P &lt; 0.001). The addition of maternal weight, PAPP-A, β-hCG, and uterine artery Doppler improved our models. Conclusion: At 11 to 14 weeks, PV is an independent predictor of pregnancy complications related to placental insufficiency, and the predictive ability is greater for FGR pregnancies with abnormal fetal Dopplers. © 2018 John Wiley &amp; Sons, Ltd

Fetal volume at 11-14 gestational weeks: Reference ranges and association with first trimester biochemical and biophysical markers

Aims: To establish reference ranges for fetal volume (FV) measured by three-dimensional ultrasound (3D-US) at 11-14 weeks of gestation and to examine the possible association of FV with maternal/pregnancy characteristics and biochemical parameters. Methods: Prospective observational study on 240 fetuses at 11-14 weeks. FV was measured by 3D-US using Virtual Organ Computer-Aided Analysis. Pearson correlation coefficient (cc) and regression analysis were used. Results: FV increased exponentially with crown rump length and was unrelated to maternal weight (cc=-0.137, P=0.071), age (cc=0.009, P=0.899), parity (0.76), smoking status (t-test, P=0.149) and mode of conception (t-test, P=0.8). Z-scores (z) of FV was not associated with z-mean uterine artery pulsatility index (cc=-0.026, P=0.733), log10 multiples of the median (MoM) free beta human chorionic gonadotrophin (cc=0.002, P=0.982), delta value (d) of nuchal translucency (cc=0.072, P=0.331) and d-fetal heart rate (cc=0.009, P=0.902), z-FV was significantly positively correlated with log10 MoM pregnancy associated plasma protein-A (PAPP-A; regression coefficient=1.420976, R2=0.0957, P&amp;lt;0.0001). Conclusions: FV is strongly related to PAPP-A even after adjustment for crown rump length with a mechanism unrelated to placental perfusion. FV is independent of the vast majority of first trimester parameters; hence, it is a promising marker of early fetal growth. © 2014 by Walter de Gruyter Berlin Boston 2014

Reproducibility study of fetal 3-D volumetry in the first trimester: Effect of fetal size and rotational angle of VOCAL software

Intra- and inter-observer reproducibility of fetal volume measurement by 3-D ultrasound scan (using VOCAL [Virtual Organ Computer-Aided Analysis] software) in 27 fetuses at 7 to 13wk was studied. For intra-observer variability, the mean difference (MD) and 95% limits of agreement (95% LOA) at 12°, 18° and 30° were MD12=0.097, 95% LOA12=-0.87 to+1.06; MD18=0.07, 95% LOA18=-1.31 to+1.45; and MD30=-0.07, 95% LOA30=-1.55 to+1.41. The standard deviation of the differences (SDDIF) increased with crown-rump length at 12° (p=0.0016), 18° (p=0.0011) and 30° (p=0.02). For inter-observer variability, MD12=0.15, 95% LOA12=-1.65 to+1.95; MD18=0.042, 95% LOA18=-1.79 to+1.87; and MD30=0.19, 95% LOA30=-1.24 to+1.62. SDDIF increased with crown-rump length at 18° (p=0.0084) and 30° (p=0.0073). The accuracy of fetal volume measurement was not influenced by rotational angle or fetal size. Precision deteriorated for wider rotational angles and larger fetuses. © 2014 World Federation for Ultrasound in Medicine &amp;amp; Biology

Increased Maternal Serum Interleukin-6 Concentrations at 11 to 14 Weeks of Gestation in Low Risk Pregnancies Complicated with Gestational Diabetes Mellitus: Development of a Prediction Model

The aim of the study was to examine interleukin-6 (IL-6) maternal serum concentration at 11 to 14 gestational weeks in normal pregnancies and pregnancies complicated by gestational diabetes mellitus (GDM) and to create first trimester prediction models for GDM. Case-control study conducted in a Fetal Medicine Unit. Study population included 40 GDM cases and 94 controls. Maternal characteristics, first trimester ultrasound markers, biochemical indices, and IL-6 levels were used for our analysis. IL-6 was related to maternal weight among the maternal characteristics, (R-2 = 0.0679, p = 0.01). IL-6 was increased (p = 0.001) in the GDM group (median = 2 pg/ml) compared to the control group (median = 1.5 pg/ml) even after adjustment for maternal weight. IL-6 was inversely related to birth weight adjusted for gestational age at delivery (r = -0.3382, p &lt; 0.001) and glucose levels at oral glucose test. Maternal weight and age were the only predictors of GDM among the maternal characteristics [Detection Rate (DR) = 59.4 %; for 25 % False Positive Rate (FPR); Area Under the Curve (AUC) = 0.7291; Model R-2 = 0.1096, p &lt; 0.001]. IL-6 alone was a significant predictor of GDM (DR = 51.3 %; for 25 % FPR; AUC = 0.6731; Model R-2 = 0.0616, p &lt; 0.001). Combination of maternal characteristics with IL-6 yielded an improved prediction (DR = 67.5 %; for 25 % FPR; AUC = 0.7586; Model R-2 = 0.1521, p &lt; 0.001). IL-6 concentrations are increased at 11-14 weeks in pregnancies with GDM. Combination of maternal characteristics and maternal serum IL-6 levels may provide effective first trimester screening for GDM