Gene Expression Profiling in a Mouse Model Identifies Fetal Liver- and Placenta-Derived Potential Biomarkers for Down Syndrome Screening

BACKGROUND: As a first step to identify novel potential biomarkers for prenatal Down Syndrome screening, we analyzed gene expression in embryos of wild type mice and the Down Syndrome model Ts1Cje. Since current Down Syndrome screening markers are derived from placenta and fetal liver, these tissues were chosen as target. METHODOLOGY/PRINCIPAL FINDINGS: Placenta and fetal liver at 15.5 days gestation were analyzed by microarray profiling. We confirmed increased expression of genes located at the trisomic chromosomal region. Overall, between the two genotypes more differentially expressed genes were found in fetal liver than in placenta. Furthermore, the fetal liver data are in line with the hematological aberrations found in humans with Down Syndrome as well as Ts1Cje mice. Together, we found 25 targets that are predicted (by Gene Ontology, UniProt, or the Human Plasma Proteome project) to be detectable in human serum. CONCLUSIONS/SIGNIFICANCE: Fetal liver might harbor more promising targets for Down Syndrome screening studies. We expect these new targets will help focus further experimental studies on identifying and validating human maternal serum biomarkers for Down Syndrome screening

The Complex Ginzburg-Landau Equation in the Presence of Walls and Corners

We investigate the influence of walls and corners (with Dirichlet and Neumann boundary conditions) in the evolution of twodimensional autooscillating fields described by the complex Ginzburg-Landau equation. Analytical solutions are found, and arguments provided, to show that Dirichlet walls introduce strong selection mechanisms for the wave pattern. Corners between walls provide additional synchronization mechanisms and associated selection criteria. The numerical results fit well with the theoretical predictions in the parameter range studied.Comment: 10 pages, 9 figures; for related work visit http://www.nbi.dk/~martine

Wound-up phase turbulence in the Complex Ginzburg-Landau equation

We consider phase turbulent regimes with nonzero winding number in the one-dimensional Complex Ginzburg-Landau equation. We find that phase turbulent states with winding number larger than a critical one are only transients and decay to states within a range of allowed winding numbers. The analogy with the Eckhaus instability for non-turbulent waves is stressed. The transition from phase to defect turbulence is interpreted as an ergodicity breaking transition which occurs when the range of allowed winding numbers vanishes. We explain the states reached at long times in terms of three basic states, namely quasiperiodic states, frozen turbulence states, and riding turbulence states. Justification and some insight into them is obtained from an analysis of a phase equation for nonzero winding number: rigidly moving solutions of this equation, which correspond to quasiperiodic and frozen turbulence states, are understood in terms of periodic and chaotic solutions of an associated system of ordinary differential equations. A short report of some of our results has been published in [Montagne et al., Phys. Rev. Lett. 77, 267 (1996)].Comment: 22 pages, 15 figures included. Uses subfigure.sty (included) and epsf.tex (not included). Related research in http://www.imedea.uib.es/Nonlinea

A nationwide retrospective observational study of population newborn screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency in the Netherlands

To evaluate the Dutch newborn screening (NBS) for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency since 2007, a nationwide retrospective, observational study was performed of clinical, laboratory and epidemiological parameters of patients with MCAD deficiency born between 2007 and 2015. Severe MCAD deficiency was defined by ACADM genotypes associated with clinical ascertainment, or variant ACADM genotypes with a residual MCAD enzyme activity <10%. Mild MCAD deficiency was defined by variant ACADM genotypes with a residual MCAD enzyme activity ≥10%. The prevalence of MCAD deficiency was 1/8300 (95% CI: 1/7300-1/9600). Sensitivity of the Dutch NBS was 99% and specificity ~100%, with a positive predictive value of 86%. Thirteen newborns with MCAD deficiency suffered from neonatal symptoms, three of them died. Of the 189 identified neonates, 24% had mild MCAD deficiency. The acylcarnitine ratio octanoylcarnitine (C8)/decanoylcarnitine (C10) was superior to C8 in discriminating between mild and severe cases and more stable in the first days of life. NBS for MCAD deficiency has a high sensitivity, specificity, and positive predictive value. In the absence of a golden standard to confirm the diagnosis, the combination of acylcarnitine (ratios), molecular and enzymatic studies allows risk stratification. To improve evaluation of NBS protocols and clinical guidelines, additional use of acylcarnitine ratios and multivariate pattern-recognition software may be reappraised in the Dutch situation. Prospective recording of NBS and follow-up data is warranted covering the entire health care chain of preventive and curative medicine

Lack of evidence for zoonotic transmission of Schmallenberg virus

The emergence of Schmallenberg virus (SBV), a novel orthobunyavirus, in ruminants in Europe triggered a joint veterinary and public health response to address the possible consequences to human health. Use of a risk profiling algorithm enabled the conclusion that the risk for zoonotic transmission of SBV could not be excluded completely. Self-reported health problems were monitored, and a serologic study was initiated among persons living and/or working on SBV-affected farms. In the study set-up, we addressed the vector and direct transmission routes for putative zoonotic transfer. In total, 69 sheep farms, 4 goat farms, and 50 cattle farms were included. No evidence for SBV-neutralizing antibodies was found in serum of 301 participants. The lack of evidence for zoonotic transmission from either syndromic illness monitoring or serologic testing of presumably highly exposed persons suggests that the public health risk for SBV, given the current situation, is absent or extremely low

External validation of prognostic models for preeclampsia in a Dutch multicenter prospective cohort

Objective: To perform an external validation of all published prognostic models for first-trimester prediction of the risk of developing preeclampsia (PE). Methods: Women <14 weeks of pregnancy were recruited in the Netherlands. All systematically identified prognostic models for PE that contained predictors commonly available were eligible for external validation. Results: 3,736 women were included; 87 (2.3%) developed PE. Calibration was poor due to overestimation. Discrimination of 9 models for LO-PE ranged from 0.58 to 0.71 and of 9 models for all PE from 0.55 to 0.75. Conclusion: Only a few easily applicable prognostic models for all PE showed discrimination above 0.70, which is considered an acceptable performance

Explaining variation in Down's syndrome screening uptake: comparing the Netherlands with England and Denmark using documentary analysis and expert stakeholder interviews.

Background: The offer of prenatal Down’s syndrome screening is part of routine antenatal care in most of Europe; however screening uptake varies significantly across countries. Although a decision to accept or reject screening is a personal choice, it is unlikely that the widely differing uptake rates across countries can be explained by variation in individual values alone. The aim of this study was to compare Down’s syndrome screening policies and programmes in the Netherlands, where uptake is relatively low ( 90% respectively), in an attempt to explain the observed variation in national uptake rates. Methods: We used a mixed methods approach with an embedded design: a) documentary analysis and b) expert stakeholder analysis. National central statistical offices and legal documents were studied first to gain insight in demographic characteristics, cultural background, organization and structure of healthcare followed by documentary analysis of primary and secondary sources on relevant documents on DSS policies and programme. To enhance interpretation of these findings we performed in-depth interviews with relevant expert stakeholders. Results: There were many similarities in the demographics, healthcare systems, government abortion legislation and Down’s syndrome screening policy across the studied countries. However, the additional cost for Down’s syndrome screening over and above standard antenatal care in the Netherlands and an emphasis on the ‘right not to know’ about screening in this country were identified as potential explanations for the ‘low’ uptake rates of Down’s syndrome screening in the Netherlands. The social context and positive framing of the offer at the service delivery level may play a role in the relatively high uptake rates in Denmark. Conclusions: This paper makes an important contribution to understanding how macro-level demographic, social and healthcare delivery factors may have an impact on national uptake rates for Down’s syndrome screening. It has suggested a number of policy level and system characteristics that may go some way to explaining the relatively low uptake rates of Down’s syndrome screening in the Netherlands when compared to England and Denmark

(Q)SARs voor humaan toxicologische eindpunten: een literatuuronderzoek

Het doel van dit rapport is het beschrijven van humaan toxicologische SARs (structuur-activiteitsrelaties) die beschikbaar zijn in de literatuur alsmede de SARs die gebruikt worden door de US EPA (Environmental Protection Agency). De implementatie van het gebruik van SARs voor de effect assessment bij CSR is onderzocht. Structuur-activiteitsrelaties (SARs) correleren de moleculaire structuur met biologisch-chemische of fysisch-chemische activiteit. In kwantitatieve structuur-activiteitsrelaties (QSARs) zijn deze correlaties gekwantificeerd. De (Q)SARs worden grofweg verdeeld in "rule-based" SARs en statistische SARs. "Rule-based" SAR gebruikt vergelijkbare stoffen (verzameld in chemische klassen) die hetzelfde werkingsmechanisme hebben. Tevens worden beschrijvers (descriptoren) afgeleid voor dit werkingsmechanisme om het effect van andere vergelijkbare stoffen te voorspellen. De statistische SAR baseert zijn voorspelling op statistisch verkregen beschrijvers van meer heterogene groepen stoffen. De ontwikkeling van de SARs gedurende de jaren hebben beide typen SAR nader tot elkaar gebracht. De gevonden (Q)SARs hebben verder validatie nodig voordat ze gebruikt kunnen worden voor de effect assessment. De onderliggende QSAR methodologie kan geimplementeerd worden. Het voorspellen van het effect van een stof vergelijkbaar met een al eerder gevalueerde stof of een chemische klasse wordt gebruikt op een ad-hoc basis bij CSR. (Q)SAR methodologie, chemische klassen, SAR kenmerken zoals electronische effecten, zouden geimplementeerd moeten worden op een meer systematische manier om de expertise over SARs en om de helderheid van de effect assessment te vergroten.The goal here was to describe human toxicological SARs (structure-activity relationships) available in the literature and used by the US EPA (Environmental Protection Agency). The CSR laboratory investigated implementation of SARs for the effect assessment. SARs correlate the molecular structure with biological-chemical or physico-chemical activity. These correlations are quantified in quantitative structure-activity relationships (QSARs). The (Q)SARs described are roughly divided into rule-based SARs and statistical SARs. The rule-based SAR uses similar chemicals (collected in chemical categories) having the same mechanism of action and descriptors for this mechanism was to predict the effect of other similar chemicals. The statistical SAR bases its prediction on statistical derived descriptors of more heterogeneous groups of chemicals. The development of SARs during the years has brought the two types of SARs together. The QSARs found need further validation before they can be used for the effect evaluation. QSAR methodology can be implemented. Predicting the effect of a chemical similar to an already assessed chemical or chemical category is used at RIVM/CSR on an ad-hoc basis for effect assessment. (Q)SAR methodology, chemical categories, and SAR features such as electronic effects should be implemented more systemically; this will increase the expertise of using SARs and the transparency of the effect assessment.RIV