Sensitivity analysis, dominant factors, and robustness of the ECETOC TRA v3, Stoffenmanager 4.5, and ART 1.5 occupational exposure models

Occupational exposure modeling is widely used in the context of the E.U. regulation on the registration, evaluation, authorization, and restriction of chemicals (REACH). First tier tools, such as European Centre for Ecotoxicology and TOxicology of Chemicals (ECETOC) targeted risk assessment (TRA) or Stoffenmanager, are used to screen a wide range of substances. Those of concern are investigated further using second tier tools, e.g., Advanced REACH Tool (ART). Local sensitivity analysis (SA) methods are used here to determine dominant factors for three models commonly used within the REACH framework: ECETOC TRA v3, Stoffenmanager 4.5, and ART 1.5. Based on the results of the SA, the robustness of the models is assessed. For ECETOC, the process category (PROC) is the most important factor. A failure to identify the correct PROC has severe consequences for the exposure estimate. Stoffenmanager is the most balanced model and decision making uncertainties in one modifying factor are less severe in Stoffenmanager. ART requires a careful evaluation of the decisions in the source compartment since it constitutes ∼75% of the total exposure range, which corresponds to an exposure estimate of 20-22 orders of magnitude. Our results indicate that there is a trade off between accuracy and precision of the models. Previous studies suggested that ART may lead to more accurate results in well-documented exposure situations. However, the choice of the adequate model should ultimately be determined by the quality of the available exposure data: if the practitioner is uncertain concerning two or more decisions in the entry parameters, Stoffenmanager may be more robust than ART.

Associations of baroreflex sensitivity, heart rate variability, and initial orthostatic hypotension with prenatal and recent postnatal methylmercury exposure in the Seychelles Child Development Study at age 19 years.

BACKGROUND: A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. METHODS: Subjects in the Seychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects' hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals); rMSSD (root mean of the squared sum of successive interval differences); LF/HF (low frequency/high frequency component ratio); ratio of the mean expiratory/inspiratory RR intervals (EI ratio); and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. RESULTS: Prenatal MeHg exposures were similar in boys and girls (6.7±4.3, 6.7±3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2±5.8 vs 7.9±4.3 ng/g, p=0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8±7 ms/mm Hg, PNN50: 24.9±6.8%, rMSSD: 68±22, LF/HF: 0.61±0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop>40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. CONCLUSIONS: This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control.

Pregnancy outcome following maternal exposure to mirtazapine: a multicenter, prospective study.

This multicenter, observational prospective cohort study addresses the risk associated with exposure to mirtazapine during pregnancy. Pregnancy outcomes after exposure to mirtazapine were compared with 2 matched control groups: (1) exposure to any selective serotonin reuptake inhibitor (SSRI, control subjects with a psychiatric condition) and (2) no exposure to medication known to be teratogenic or any antidepressant (general control subjects). Data were collected by members of the European Network of Teratology Information Services between 1995 and 2011. Observations from 357 exposed pregnancies were compared with 357 pregnancies from each control group. The rate of major birth defects between the mirtazapine and the SSRI group did not differ significantly (4.5% vs 4.2%; odds ratio [OR], 1.1; 95% confidence interval [95% CI], 0.5-2.3; P = 0.9). A trend toward a higher rate of birth defects in the mirtazapine group compared with general control subjects (4.5% vs 1.9%; OR, 2.4; 95% CI, 0.9-6.3; P = 0.08) reached statistical significance after exclusion of chromosomal or genetic anomalies (4.1% vs 1.3%; OR, 3.3; 95% CI, 1.04-10.3; P = 0.03), but this difference became again nonsignificant if cases of exposure not comprising the first trimester were excluded from the analysis (3.4% vs 1.9%; OR, 1.8; 95% CI, 0.6-5.0; P = 0.26). The crude miscarriage rate did not differ significantly between the mirtazapine, the SSRI, and the general control groups (12.1% vs 12.0% vs 9.3%; P = 0.44). However, a higher rate of elective pregnancy termination was observed in the mirtazapine group compared with SSRI and general control subjects (7.8% vs 3.4% vs 5.6%; P = 0.03). This study did not observe a statistically significant difference in the rate of major birth defects after first-trimester exposure between mirtazapine, SSRI-exposed, and nonexposed pregnancies. A marginally higher rate of birth defects was, however, observed in the mirtazapine and SSRI groups compared with the low rate of birth defects in our general control subjects. Overall pregnancy outcome after mirtazapine exposure was similar to that of the SSRI-exposed control group.

Right ventricular dysfunction in children and adolescents conceived by assisted reproductive technologies.

Assisted reproductive technologies (ART) predispose the offspring to vascular dysfunction, arterial hypertension, and hypoxic pulmonary hypertension. Recently, cardiac remodeling and dysfunction during fetal and early postnatal life have been reported in offspring of ART, but it is not known whether these cardiac alterations persist later in life and whether confounding factors contribute to this problem. We, therefore, assessed cardiac function and pulmonary artery pressure by echocardiography in 54 healthy children conceived by ART (mean age 11.5 ± 2.4 yr) and 54 age-matched (12.2 ± 2.3 yr) and sex-matched control children. Because ART is often associated with low birth weight and prematurity, two potential confounders associated with cardiac dysfunction, only singletons born with normal birth weight at term were studied. Moreover, because cardiac remodeling in infants conceived by ART was observed in utero, a situation associated with increased right heart load, we also assessed cardiac function during high-altitude exposure, a condition associated with hypoxic pulmonary hypertension-induced right ventricular overload. We found that, while at low altitude cardiac morphometry and function was not different between children conceived by ART and control children, under the stressful conditions of high-altitude-induced pressure overload and hypoxia, larger right ventricular end-diastolic area and diastolic dysfunction (evidenced by lower E-wave tissue Doppler velocity and A-wave tissue Doppler velocity of the lateral tricuspid annulus) were detectable in children and adolescents conceived by ART. In conclusion, right ventricular dysfunction persists in children and adolescents conceived by ART. These cardiac alterations appear to be related to ART per se rather than to low birth weight or prematurity.

Was bringt die Masern-Passivimpfung nach Exposition? [What is the value of measles passive vaccination after exposure?].

In der Schweiz, wie in vielen anderen Ländern, ist die Durchimpfungsrate zu tief, um die Verbreitung von Masern zu stoppen. Es kommt immer wieder zu Masern-Ausbrüchen. Die Gabe von Immunglobulinen (Passivimpfung) ist für nicht-immune Personen gedacht, die Kontakt zu Masernvirus-Ausscheidern hatten. Sie wird in der Schweiz für Hochrisiko-Personen wie z.B. schwangere Frauen, immunsupprimierte Personen und Säuglinge <6 Monate ohne nachgewiesene Immunität empfohlen. Schätzungen über die Wirksamkeit der Passivimpfung variieren; es wurde keine minimalwirksame Dosierung festgelegt. Ziel dieses Reviews war, die Wirksamkeit und Sicherheit einer intramuskulären oder intravenösen Gabe von Immunglobulinen zur Masern-Prophylaxe nach Exposition jedoch vor Symptombeginn bei für Masern empfänglichen Personen zu untersuchen.

Posttraumatic stress avoidance symptoms as mediators in the development of alcohol use disorders after exposure to childhood sexual abuse in a Swiss community sample.

This study examined the role of posttraumatic stress disorder (PTSD) symptoms of re-experience, avoidance, and hyperarousal in the relationship between different types of trauma and alcohol use disorders (AUD). We used data from 731 trauma-exposed individuals who participated in the first wave of the PsyCoLaus-study. Trauma characteristics were assessed relatively to the occurrence of lifetime PTSD symptoms and AUD. The results suggest that lifetime and childhood sexual abuse as well as overall childhood trauma were directly linked to AUD and PTSD symptoms, in particular to avoidance symptoms. From single symptom clusters PTSD avoidance was found to specifically mediate the trauma-AUD pathway. Both childhood and sexual trauma strongly contribute to the comorbidity of PTSD and AUD and avoidance-type symptoms appear to play a central role in maintaining this association. Hence, the alleviation of avoidance symptoms might be an important target for therapeutic intervention among victims of sexual abuse before specific addiction treatment is initiated.

Prenatal Exposure to DEHP Affects Spermatogenesis and Sperm DNA Methylation in a Strain-Dependent Manner.

Di-(2-ethylhexyl)phtalate (DEHP) is a plasticizer with endocrine disrupting properties found ubiquitously in the environment and altering reproduction in rodents. Here we investigated the impact of prenatal exposure to DEHP on spermatogenesis and DNA sperm methylation in two distinct, selected, and sequenced mice strains. FVB/N and C57BL/6J mice were orally exposed to 300 mg/kg/day of DEHP from gestation day 9 to 19. Prenatal DEHP exposure significantly decreased spermatogenesis in C57BL/6J (fold-change = 0.6, p-value = 8.7*10-4), but not in FVB/N (fold-change = 1, p-value = 0.9). The number of differentially methylated regions (DMRs) by DEHP-exposure across the entire genome showed increased hyper- and decreased hypo-methylation in C57BL/6J compared to FVB/N. At the promoter level, three important subsets of genes were massively affected. Promoters of vomeronasal and olfactory receptors coding genes globally followed the same trend, more pronounced in the C57BL/6J strain, of being hyper-methylated in DEHP related conditions. In contrast, a large set of micro-RNAs were hypo-methylated, with a trend more pronounced in the FVB/N strain. We additionally analyze both the presence of functional genetic variations within genes that were associated with the detected DMRs and that could be involved in spermatogenesis, and DMRs related with the DEHP exposure that affected both strains in an opposite manner. The major finding in this study indicates that prenatal exposure to DEHP can decrease spermatogenesis in a strain-dependent manner and affects sperm DNA methylation in promoters of large sets of genes putatively involved in both sperm chemotaxis and post-transcriptional regulatory mechanisms.

Childhood sexual and physical abuse: age at exposure modulates impact on functional outcome in early psychosis patients.

BACKGROUND: Evidence suggests a relationship between exposure to trauma during childhood and functional impairments in psychotic patients. However, the impact of age at the time of exposure has been understudied in early psychosis (EP) patients. METHOD: Two hundred and twenty-five patients aged 18-35 years were assessed at baseline and after 2, 6, 18, 24, 30 and 36 months of treatment. Patients exposed to sexual and/or physical abuse (SPA) were classified according to age at the time of first exposure (Early SPA: before age 11 years; Late SPA: between ages 12 and 15 years) and then compared to patients who were not exposed to such trauma (Non-SPA). The functional level in the premorbid phase was measured with the Premorbid Adjustment Scale (PAS) and with the Global Assessment of Functioning (GAF) scale and the Social and Occupational Functioning Assessment Scale (SOFAS) during follow-up. RESULTS: There were 24.8% of patients with a documented history of SPA. Late SPA patients were more likely to be female (p = 0.010). Comparison with non-SPA patients revealed that: (1) both Early and Late SPA groups showed poorer premorbid social functioning during early adolescence, and (2) while patients with Early SPA had poorer functional level at follow-up with lower GAF (p = 0.025) and lower SOFAS (p = 0.048) scores, Late SPA patients did not. CONCLUSION: Our results suggest a link between exposure to SPA and the later impairment of social functioning before the onset of the disease. EP patients exposed to SPA before age 12 may present long-lasting functional impairment, while patients exposed at a later age may improve in this regard and have a better functional outcome.

An efficient total variation algorithm for super-resolution in fetal brain MRI with adaptive regularization.

Although fetal anatomy can be adequately viewed in new multi-slice MR images, many critical limitations remain for quantitative data analysis. To this end, several research groups have recently developed advanced image processing methods, often denoted by super-resolution (SR) techniques, to reconstruct from a set of clinical low-resolution (LR) images, a high-resolution (HR) motion-free volume. It is usually modeled as an inverse problem where the regularization term plays a central role in the reconstruction quality. Literature has been quite attracted by Total Variation energies because of their ability in edge preserving but only standard explicit steepest gradient techniques have been applied for optimization. In a preliminary work, it has been shown that novel fast convex optimization techniques could be successfully applied to design an efficient Total Variation optimization algorithm for the super-resolution problem. In this work, two major contributions are presented. Firstly, we will briefly review the Bayesian and Variational dual formulations of current state-of-the-art methods dedicated to fetal MRI reconstruction. Secondly, we present an extensive quantitative evaluation of our SR algorithm previously introduced on both simulated fetal and real clinical data (with both normal and pathological subjects). Specifically, we study the robustness of regularization terms in front of residual registration errors and we also present a novel strategy for automatically select the weight of the regularization as regards the data fidelity term. Our results show that our TV implementation is highly robust in front of motion artifacts and that it offers the best trade-off between speed and accuracy for fetal MRI recovery as in comparison with state-of-the art methods.

Fetal laser therapy: applications in the management of fetal pathologies.

Fetoscopic coagulation of placental anastomoses is the treatment of choice for severe twin-to-twin transfusion syndrome. In the present day, fetal laser therapy is also used to treat amniotic bands, chorioangiomas, sacrococcygeal teratomas, lower urinary tract obstructions and chest masses, all of which will be reviewed in this article. Amniotic band syndrome can cause limb amputation by impairing downstream blood flow. Large chorioangiomas (>4 cm), sacrococcygeal teratomas or fetal hyperechoic lung lesions can lead to fetal compromise and hydrops by vascular steal phenomenon or compression. Renal damage, bladder dysfunction and lastly death because of pulmonary hypolasia may be the result of megacystis caused by a posterior urethral valve. The prognosis of these pathologies can be dismal, and therapy options are limited, which has brought fetal laser therapy to the forefront. Management options discussed here are laser release of amniotic bands, laser coagulation of the placental or fetal tumor feeding vessels and laser therapy by fetal cystoscopy. This review, largely based on case reports, does not intend to provide a level of evidence supporting laser therapy over other treatment options. Centralized evaluation by specialists using strict selection criteria and long-term follow-up of these rare cases are now needed to prove the value of endoscopic or ultrasound-guided laser therapy.