Long-term exposure to traffic-related air pollution and non-accidental mortality: A systematic review and meta-analysis

BACKGROUND

The health effects of traffic-related air pollution (TRAP) continue to be of important public health interest across the globe. Following its 2010 review, the Health Effects Institute appointed a new expert Panel to systematically evaluate the epidemiological evidence regarding the associations between long-term exposure to TRAP and selected health outcomes. This paper describes the main findings of the systematic review on non-accidental mortality.

METHODS

The Panel used a systematic approach to conduct the review. An extensive search was conducted of literature published between 1980 and 2019. A new exposure framework was developed to determine whether a study was sufficiently specific to TRAP, which included studies beyond the near-roadway environment. We performed random-effects meta-analysis when at least three estimates were available of an association between a specific exposure and outcome. We evaluated confidence in the evidence using a modified Office of Health Assessment and Translation (OHAT) approach, supplemented with a broader narrative synthesis.

RESULTS

Thirty-six cohort studies were included. Virtually all studies adjusted for a large number of individual and area-level covariates-including smoking, body mass index, and individual and area-level socioeconomic status-and were judged at a low or moderate risk for bias. Most studies were conducted in North America and Europe, and a few were based in Asia and Australia. The meta-analytic summary estimates for nitrogen dioxide, elemental carbon and fine particulate matter-pollutants with more than 10 studies-were 1.04 (95% CI 1.01, 1.06), 1.02 (1.00, 1.04) and 1.03 (1.01, 1.05) per 10, 1 and 5 µg/m³, respectively. Effect estimates are interpreted as the relative risk of mortality when the exposure differs with the selected increment. The confidence in the evidence for these pollutants was judged as high, because of upgrades for monotonic exposure-response and consistency across populations. The consistent findings across geographical regions, exposure assessment methods and confounder adjustment resulted in a high confidence rating using a narrative approach as well.

CONCLUSIONS

The overall confidence in the evidence for a positive association between long-term exposure to TRAP and non-accidental mortality was high.

Exploring isofunctional molecules: Design of a benchmark and evaluation of prediction performance

Identification of novel chemotypes with biological activity similar to a known active molecule is an important challenge in drug discovery called 'scaffold hopping'. Small-, medium-, and large-step scaffold hopping efforts may lead to increasing degrees of chemical structure novelty with respect to the parent compound. In the present paper, we focus on the problem of large-step scaffold hopping. We assembled a high quality and well characterized dataset of scaffold hopping examples comprising pairs of active molecules and including a variety of protein targets. This dataset was used to build a benchmark corresponding to the setting of real-life applications: one active molecule is known, and the second active is searched among a set of decoys chosen in a way to avoid statistical bias. This allowed us to evaluate the performance of computational methods for solving large-step scaffold hopping problems. In particular, we assessed how difficult these problems are, particularly for classical 2D and 3D ligand-based methods. We also showed that a machine-learning chemogenomic algorithm outperforms classical methods and we provided some useful hints for future improvements.

Long-term exposure to traffic-related air pollution and stroke: A systematic review and meta-analysis

BACKGROUND

Stroke remains the second cause of death worldwide. The mechanisms underlying the adverse association of exposure to traffic-related air pollution (TRAP) with overall cardiovascular disease may also apply to stroke. Our objective was to systematically evaluate the epidemiological evidence regarding the associations of long-term exposure to TRAP with stroke.

METHODS

PubMed and LUDOK electronic databases were searched systematically for observational epidemiological studies from 1980 through 2019 on long-term exposure to TRAP and stroke with an update in January 2022. TRAP was defined according to a comprehensive protocol based on pollutant and exposure assessment methods or proximity metrics. Study selection, data extraction, risk of bias (RoB) and confidence assessments were conducted according to standardized protocols. We performed meta-analyses using random effects models; sensitivity analyses were assessed by geographic area, RoB, fatality, traffic specificity and new studies.

RESULTS

Nineteen studies were included. The meta-analytic relative risks (and 95% confidence intervals) were: 1.03 (0.98-1.09) per 1 μg/m³ EC, 1.09 (0.96-1.23) per 10 μg/m³ PM₁₀, 1.08 (0.89-1.32) per 5 μg/m³ PM_2.5, 0.98 (0.92; 1.05) per 10 μg/m³ NO₂ and 0.99 (0.94; 1.04) per 20 μg/m³ NO_x with little to moderate heterogeneity based on 6, 5, 4, 7 and 8 studies, respectively. The confidence assessments regarding the quality of the body of evidence and separately regarding the presence of an association of TRAP with stroke considering all available evidence were rated low and moderate, respectively.

CONCLUSION

The available literature provides low to moderate evidence for an association of TRAP with stroke.

Intrinsic cell rheology drives junction maturation

A fundamental property of higher eukaryotes that underpins their evolutionary success is stable cell-cell cohesion. Yet, how intrinsic cell rheology and stiffness contributes to junction stabilization and maturation is poorly understood. We demonstrate that localized modulation of cell rheology governs the transition of a slack, undulated cell-cell contact (weak adhesion) to a mature, straight junction (optimal adhesion). Cell pairs confined on different geometries have heterogeneous elasticity maps and control their own intrinsic rheology co-ordinately. More compliant cell pairs grown on circles have slack contacts, while stiffer triangular cell pairs favour straight junctions with flanking contractile thin bundles. Counter-intuitively, straighter cell-cell contacts have reduced receptor density and less dynamic junctional actin, suggesting an unusual adaptive mechano-response to stabilize cell-cell adhesion. Our modelling informs that slack junctions arise from failure of circular cell pairs to increase their own intrinsic stiffness and resist the pressures from the neighbouring cell. The inability to form a straight junction can be reversed by increasing mechanical stress artificially on stiffer substrates. Our data inform on the minimal intrinsic rheology to generate a mature junction and provide a springboard towards understanding elements governing tissue-level mechanics.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Long-term exposure to traffic-related air pollution and selected health outcomes: A systematic review and meta-analysis

The health effects of traffic-related air pollution (TRAP) continue to be of important public health interest. Following its well-cited 2010 critical review, the Health Effects Institute (HEI) appointed a new expert Panel to systematically evaluate the epidemiological evidence regarding the associations between long-term exposure to TRAP and selected adverse health outcomes. Health outcomes were selected based on evidence of causality for general air pollution (broader than TRAP) cited in authoritative reviews, relevance for public health and policy, and resources available. The Panel used a systematic approach to search the literature, select studies for inclusion in the review, assess study quality, summarize results, and reach conclusions about the confidence in the evidence. An extensive search was conducted of literature published between January 1980 and July 2019 on selected health outcomes. A new exposure framework was developed to determine whether a study was sufficiently specific to TRAP. In total, 353 studies were included in the review. Respiratory effects in children (118 studies) and birth outcomes (86 studies) were the most commonly studied outcomes. Fewer studies investigated cardiometabolic effects (57 studies), respiratory effects in adults (50 studies), and mortality (48 studies). The findings from the systematic review, meta-analyses, and evaluation of the quality of the studies and potential biases provided an overall high or moderate-to-high level of confidence in an association between long-term exposure to TRAP and the adverse health outcomes all-cause, circulatory, ischemic heart disease and lung cancer mortality, asthma onsetin chilldren and adults, and acute lower respiratory infections in children. The evidence was considered moderate, low or very low for the other selected outcomes. In light of the large number of people exposed to TRAP - both in and beyond the near-road environment - the Panel concluded that the overall high or moderate-to-high confidence in the evidence for an association between long-term exposure to TRAP and several adverse health outcomes indicates that exposures to TRAP remain an important public health concern and deserve greater attention from the public and from policymakers.

On the Frustration to Predict Binding Affinities from Protein-Ligand Structures with Deep Neural Networks

Accurate prediction of binding affinities from protein-ligand atomic coordinates remains a major challenge in early stages of drug discovery. Using modular message passing graph neural networks describing both the ligand and the protein in their free and bound states, we unambiguously evidence that an explicit description of protein-ligand noncovalent interactions does not provide any advantage with respect to ligand or protein descriptors. Simple models, inferring binding affinities of test samples from that of the closest ligands or proteins in the training set, already exhibit good performances, suggesting that memorization largely dominates true learning in the deep neural networks. The current study suggests considering only noncovalent interactions while omitting their protein and ligand atomic environments. Removing all hidden biases probably requires much denser protein-ligand training matrices and a coordinated effort of the drug design community to solve the necessary protein-ligand structures.

Management strategies for adult patients with dental anxiety in the dental clinic: a systematic review

Anxiety is an adaptive emotional response to potentially threatening or dangerous situations; moderated by the sympathetic nervous system. Dental anxiety is common and presents before, during or after dental treatment. The physiological response includes an increase in heart rate, blood pressure, respiratory rate, and cardiac output. Consequently, extensive distress leads to avoidance of dental treatment and multiple failed appointments, impacting both oral and general health. Dental anxiety can generate a variety of negative consequences for both the dentist and the patient. Evidence-based strategies are essential for mitigating and relieving anxiety in the dental clinic. Psychotherapeutic behavioural strategies can modify the patient's experience through a minimally invasive approach with nil or negligible side effects, depending on patient characteristics, anxiety level and clinical situations. These therapies involve muscle relaxation, guided imagery, physiological monitoring, utilizing biofeedback, hypnosis, acupuncture, distraction and desensitization. Pharmacological intervention utilizes either relative analgesia (nitrous oxide), conscious intravenous sedation or oral sedation, which can have undesirable side effects, risks and contraindications. These modalities increase the cost and availability of dental treatment.

New insights into structure and function of bis-phosphinic acid derivatives and implications for CFTR modulation

C407 is a compound that corrects the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein carrying the p.Phe508del (F508del) mutation. We investigated the corrector effect of c407 and its derivatives on F508del-CFTR protein. Molecular docking and dynamics simulations combined with site-directed mutagenesis suggested that c407 stabilizes the F508del-Nucleotide Binding Domain 1 (NBD1) during the co-translational folding process by occupying the position of the p.Phe1068 side chain located at the fourth intracellular loop (ICL4). After CFTR domains assembly, c407 occupies the position of the missing p.Phe508 side chain. C407 alone or in combination with the F508del-CFTR corrector VX-809, increased CFTR activity in cell lines but not in primary respiratory cells carrying the F508del mutation. A structure-based approach resulted in the synthesis of an extended c407 analog G1, designed to improve the interaction with ICL4. G1 significantly increased CFTR activity and response to VX-809 in primary nasal cells of F508del homozygous patients. Our data demonstrate that in-silico optimized c407 derivative G1 acts by a mechanism different from the reference VX-809 corrector and provide insights into its possible molecular mode of action. These results pave the way for novel strategies aiming to optimize the flawed ICL4-NBD1 interface.

Functional and Pharmacological Characterization of the Rare CFTR Mutation W361R

Understanding the functional consequence of rare cystic fibrosis (CF) mutations is mandatory for the adoption of precision therapeutic approaches for CF. Here we studied the effect of the very rare CF mutation, W361R, on CFTR processing and function. We applied western blot, patch clamp and pharmacological modulators of CFTR to study the maturation and ion transport properties of pEGFP-WT and mutant CFTR constructs, W361R, F508del and L69H-CFTR, expressed in HEK293 cells. Structural analyses were also performed to study the molecular environment of the W361 residue. Western blot showed that W361R-CFTR was not efficiently processed to a mature band C, similar to F508del CFTR, but unlike F508del CFTR, it did exhibit significant transport activity at the cell surface in response to cAMP agonists. Importantly, W361R-CFTR also responded well to CFTR modulators: its maturation defect was efficiently corrected by VX-809 treatment and its channel activity further potentiated by VX-770. Based on these results, we postulate that W361R is a novel class-2 CF mutation that causes abnormal protein maturation which can be corrected by VX-809, and additionally potentiated by VX-770, two FDA-approved small molecules. At the structural level, W361 is located within a class-2 CF mutation hotspot that includes other mutations that induce variable disease severity. Analysis of the 3D structure of CFTR within a lipid environment indicated that W361, together with other mutations located in this hotspot, is at the edge of a groove which stably accommodates lipid acyl chains. We suggest this lipid environment impacts CFTR folding, maturation and response to CFTR modulators.

Unsolved severe chronic rhinosinusitis elucidated by extensive CFTR genotyping

Severe chronic rhinosinusitis in children should alert clinicians and extensive CFTR genotyping should be performed. We propose that thorough clinical and functional assessment in severe chronic rhinosinusitis is valuable to discover rare mutations which could be treated by CFTR correctors to postpone pulmonary infection.

[Breathing: Ambient Air Pollution and Health - Part III]

The third part of the DGP statement introduces the current body of knowledge on less studied health outcomes associated with exposure to ambient air pollution: the negative impact on metabolism leading to impaired glucose tolerance and diabetes as well as contribution to the development of neurodegenerative disorders and delayed cognitive function in children. Furthermore, prenatal exposure and adverse effects on mother and child are addressed. Finally, the currently discussed biological mechanisms underlying various health effects associated with exposure to air pollution are described.Differing, but often complementary biological mechanisms create the basis for the diverse health outcomes caused by air pollution. Oxidative stress and a subclinical inflammatory response in the lungs and on a systemic level ("low-grade systemic inflammation") are considered to be key mechanisms. They promote secondary alterations in the body, such as vascular or metabolic processes, and may also result in the currently studied epigenetic phenomena or neuroinflammation. In this context, the health significance of soluble particulate matter and the role of ultrafine particles translocated across biological membranes into blood vessel and transported via the circulation to secondary target organs, such as liver, brain or the fetus, are intensively discussed.Diabetes is one of the leading chronic diseases worldwide, with a prevalence of almost 14 % in Germany. Although lifestyle factors are the main causes, current evidence suggests that long-term exposure to air pollution may additionally increase the risk for type 2 diabetes. Supporting evidence for a causal role of air pollution is provided by studies addressing the regulation of the blood glucose levels in metabolically healthy participants, insulin sensitivity, or pregnancy-related diabetes. Experimental studies provide further support for plausible biological mechanisms. However, prospective studies are needed to gain more evidence, taking multiple lifestyle and environmental factors, such as green space and noise, and an improved individual exposure assessment into account.The aging population has an increased risk of neurodegenerative diseases. First studies point towards a contribution of chronic exposure to air pollution, specifically by particulate matter. Several studies report its association with decreased neurocognitive capacity or an increased prevalence of dementia or Alzheimer's disease in adults. However, the studies are inhomogeneous regarding design, exposure and outcome, leading to inconsistent results. With respect to the influence on neurocognitive development of children, first studies suggest an association between the level of air pollution, e. g. at school, and delayed cognitive development.Even though the evidence for the different biological endpoints during pregnancy is still heterogeneous, the studies generally point towards an adverse impact of air pollution on the maternal and fetal organisms. The strongest evidence exists for low birth weight, with small effect sizes of only some grams, and for a higher incidence of reduced birth weight (< 2500 g). An increased risk for gestational hypertension and preeclampsia underscores the possible impact of exposure to air pollution on the maternal organism. However, the current body of evidence does not yet allow a final conclusion on the influence of intrauterine exposure to air pollution regarding early childhood lung function and development of allergies, particularly in light of the fact that it is hard to distinguish in epidemiological studies between the effects of pre- and postnatal exposure.

[Breathing: Ambient Air Pollution and Health - Part II]

The second part of the DGP-statement on adverse health effects of ambient air pollution provides an overview of the current ambient air quality in Germany and its development in the past 20 years. Further, effects of air pollution on the cardiovascular system und underlying pathophysiological mechanisms are introduced. Air pollutants form a highly complex and dynamic system of thousands of organic and inorganic components from natural and anthropogenic sources. The pollutants are produced locally or introduced by long-range transport over hundreds of kilometers and are additionally subjected to local meteorological conditions. According to air quality regulations ambient air quality is monitored under uniform standards including immission of particulate matter, up to 2.5 µm (PM_2.5) or 10 µm (PM₁₀) in aerodynamic diameter, and of nitrogen dioxide (NO₂) or ozone (O₃). The clean air measures of recent years led to a continuous decline of air pollution in the past 20 years in Germany. Accordingly, the focus is nowadays directed at population-related health hazards caused by low concentrations of air pollution. Exceeded limits for sulfur dioxide, carbon monoxide, benzene and lead are not detected anymore. Also the number of days with increased ozone concentration declined, although the annual mean concentration is unaltered. Decreasing concentrations of particulate matter and NO₂ have been observed, however, about 40 % of the monitoring stations at urban traffic sites still measure values exceeding current limits for NO₂. Moreover, the stricter, solely health-based WHO-standards for PM_2.5, PM₁₀ and NO₂ are still not met so that an optimal protection from air pollution-related health hazards is currently not given for the German population. In recent years, the findings of numerous cross-sectional and longitudinal studies underscored adverse effects of air pollution on the cardiovascular system, especially for particulate matter, although the level of evidence still varies for the different health outcomes. Further, the studies show that cardiovascular health hazards on the population level are of higher relevance than those for the respiratory system. The existing evidence for cardiovascular mortality, hospitalization, ischemic heart diseases, myocardial infarction and stroke can be regarded as strong, while that for heart failure is rather moderate. While the evidence for air pollution-related short-term alteration of the cardiac autonomic balance can be considered as sufficient, long-term effects are still unclear. Likewise, the heterogeneous findings on air pollution-related arrhythmia do currently not allow a distinct conclusion in this regard. A large number of studies support the observation that both, short- and long-term air pollution exposure contribute to increased blood pressure, may impair vascular homeostasis, induce endothelial dysfunction and promote the progression of atherosclerotic lesions. These effects provide reasonable biological explanation for the fatal events associated with exposure to air pollution. Short-term exposure may not pose a significant risk on healthy individuals but may be considered as precursor for fatal events in susceptible populations, while repetitive or long-term exposure may contribute to the development of cardiovascular diseases even in healthy subjects.

Could we expect new praziquantel derivatives? A meta pharmacometrics/pharmacoinformatics analysis of all antischistosomal praziquantel derivatives found in the literature

Praziquantel (PZQ) is the first line drug for the treatment of human Schistosoma spp. worm infections. However, it suffers from low activity towards immature stages of the worm, and its prolonged use induces resistance/tolerance. During the last 40 years, 263 PZQ analogues have been synthesized and tested against Schistosoma spp. worms, but less than 10% of them showed significant activity. Here, we propose a rationalization of the chemical space of the PZQ derivatives by a ligand-based approach. First, we constructed an in-house database with all PZQ derivatives available in the literature. This analysis shows a high heterogeneity in the data. Fortunately, all studies include PZQ as a reference, permitting the classification of compounds into three classes according to their activities. Models involving ligand-based pharmacophore and logistic regression were performed. Five physicochemical parameters were identified as the best to explain the biological activity. In the end, we proposed new PZQ derivatives with modifications at positions 1 and 7, we analysed them with our models, and we observed that they can be more active than the previously synthesized derivatives. The main goal of this work was to conduct the most valuable meta-pharmacometrics/pharmacoinformatics analysis with all Praziquantel medicinal chemistry data available in the literature.

[Breathing: Ambient Air Pollution and Health - Part I]

Die Exposition gegenüber Luftschadstoffen wird von der Weltgesundheitsorganisation weltweit als eine führende Gesundheitsgefährdung und als der wichtigste umweltbedingte Risikofaktor mit besonders hoher Krankheitslast in Ländern mit niedrigem und mittlerem Einkommen angesehen.

Die Luftschadstoffbelastung besteht aus hochkomplexen Gemischen verschiedenster organischer und anorganischer Bestandteile natürlichen oder anthropogenen Ursprungs, die lokal entstehen oder durch Ferntransport über hunderte von Kilometern regional eingebracht werden können. Zusätzlich wird die Schadstoffkonzentration durch die regionalen, meteorologischen Verhältnisse beeinflusst. Dementsprechend können Schadstoffkonzentration und Zusammensetzung an einem Ort deutlich variieren, zeigen aber typischerweise einen Tages-, Wochen- und Jahresgang.

Mittels gesetzlicher Grenzwerte wie in der „Air Quality Directive“ der Europäischen Union festgelegt, soll eine Gesundheitsgefährdung der Bevölkerung durch die Schadstoffe minimiert werden. Allerdings weichen die Grenzwerte der Europäischen Union von den Empfehlungen der WHO insbesondere für Feinstaub deutlich nach oben ab.

Zur Abschätzung der Luftschadstoffbelastung wird auf einzelne Indikatoren zurückgegriffen, die die partikuläre, wie Feinstaub bis 2,5 µm (PM2.5) bzw. bis 10 µm aerodynamischen Durchmesser (PM10), und die gasförmige Belastung, wie Stickstoffdioxid (NO2) und Ozon (O3), charakterisieren. Für die meisten Luftschadstoffe wurden über die letzten Jahrzehnte in der westlichen Welt abfallende Konzentrationen beobachtet, sodass hier v. a. die Gesundheitsgefährdung bei geringerer Schadstoffbelastung im Vordergrund steht. Insbesondere Ballungsgebiete in Deutschland leiden aber noch unter erhöhter Luftverschmutzung.

Zahlreiche Studien haben in den letzten Jahrzehnten schädliche Auswirkungen von Luftschadstoffen auf die Gesundheit der Bevölkerung belegt. Die Auswirkungen betreffen v. a. den Atemtrakt und das kardiovaskuläre System und reichen von unspezifischen Atemwegs- und kardiovaskulären Symptomen über Beeinträchtigungen der Lungenfunktion, vermehrter Medikamenteneinnahme und akuter Exazerbation von vorbestehenden Lungenerkrankungen, Herzinfarkten und Schlaganfällen bis hin zu Todesfällen. Neuere Studien weisen auf weitere Gesundheitsendpunkte, wie z. B. Atherosklerose, Einschränkungen des fetalen Wachstums, der kognitiven Funktion und neuronalen Entwicklung, Diabetes mellitus sowie auf ein verbessertes Verständnis der zugrundeliegenden pathophysiologischen Mechanismen hin.

In der „Global Burden of Disease Study“ von 2015 wird die Bedeutung der Luftschadstoffbelastung für Mortalität und Morbidität v. a. durch chronische Erkrankungen quantifiziert. Bei der vorzeitigen Mortalität, v. a. aufgrund von kardiovaskulären Todesursachen, lag PM2.5 in der Außenluft weltweit auf Rang 5, unmittelbar hinter den allgemeinen Risikofaktoren erhöhter Blutdruck, Rauchen sowie erhöhte Glukose- und Cholesterinwerte. In Deutschland liegt die Krankheitslast durch Luftverschmutzung an zehnter Stelle der Risikofaktoren und ist damit auch hierzulande der wichtigste umweltbezogene Risikofaktor. Entsprechend zeigen Studien, dass der Einfluss von Luftschadstoffen die Sterblichkeit in Europa erhöht und die mittlere Lebenserwartung um etwa ein Jahr reduzieren kann.

In dem hier vorgestellten Positionspapier fasst die Deutsche Gesellschaft für Pneumologie und Beatmungsmedizin den aktuellen Wissensstand zu den Gesundheitseffekten von Luftschadstoffen zusammen und leitet daraus Empfehlungen für einen umweltbezogenen Gesundheitsschutz ab. Der hier vorgestellte erste Teil fokussiert sich auf allgemeine Grundlagen und die Wirkungen im Atemtrakt.

CPP-ACP Promotes SnF2 Efficacy in a Polymicrobial Caries Model

Dental caries is associated with plaque dysbiosis, leading to an increase in the proportions of acidogenic and aciduric bacteria at the expense of alkali-generating commensal species. Stannous fluoride (SnF₂) slows the progression of caries by remineralization of early lesions but has also been suggested to inhibit glycolysis of aciduric bacteria. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) promotes fluoride remineralization by acting as a salivary biomimetic that releases bioavailable calcium and phosphate ions, and the peptide complex has also been suggested to modify plaque composition. We developed a polymicrobial biofilm model of caries using 6 bacterial species representative of supragingival plaque that were cultured on sound human enamel and pulsed with sucrose 4 times a day to produce a high cariogenic challenge. We used this model to explore the mechanisms of action of SnF₂ and CPP-ACP. Bacterial species in the biofilms were enumerated with 16S rRNA gene sequence analyses, and mineral loss and lesion formation were determined in the enamel directly under the polymicrobial biofilms via transverse microradiography. The model tested the twice-daily addition of SnF₂, CPP-ACP, or both. SnF₂ treatment reduced demineralization by 50% and had a slight effect on the composition of the polymicrobial biofilm. CPP-ACP treatment caused a similar inhibition of enamel demineralization (50%), a decrease in Actinomyces naeslundii and Lactobacillus casei abundance, and an increase in Streptococcus sanguinis and Fusobacterium nucleatum abundance in the polymicrobial biofilm. A combination of SnF₂ and CPP-ACP resulted in a greater suppression of the acidogenic and aciduric bacteria and a significant 72% inhibition of enamel demineralization.

Combining theoretical and experimental data to decipher CFTR 3D structures and functions

Cryo-electron microscopy (cryo-EM) has recently provided invaluable experimental data about the full-length cystic fibrosis transmembrane conductance regulator (CFTR) 3D structure. However, this experimental information deals with inactive states of the channel, either in an apo, quiescent conformation, in which nucleotide-binding domains (NBDs) are widely separated or in an ATP-bound, yet closed conformation. Here, we show that 3D structure models of the open and closed forms of the channel, now further supported by metadynamics simulations and by comparison with the cryo-EM data, could be used to gain some insights into critical features of the conformational transition toward active CFTR forms. These critical elements lie within membrane-spanning domains but also within NBD1 and the N-terminal extension, in which conformational plasticity is predicted to occur to help the interaction with filamin, one of the CFTR cellular partners.

SULFATION PATHWAYS: Formation and hydrolysis of sulfonated estrogens in the porcine testis and epididymis

Boars exhibit high concentrations of sulfonated estrogens (SE) mainly originating from the testicular-epididymal compartment. Intriguingly, in porcine Leydig cells, sulfonation of estrogens is colocalized with aromatase and steroid sulfatase (STS), indicating that de novo synthesis of unconjugated estrogens (UE), their sulfonation and hydrolysis of SE occur within the same cell type. So far in boars no plausible concept concerning the role of SE has been put forward. To obtain new information on SE formation and hydrolysis, the porcine testicular-epididymal compartment was screened for the expression of the estrogen-specific sulfotransferase SULT1E1 and STS applying real-time RT-qPCR, Western blot and immunohistochemistry. The epididymal head was identified as the major site of SULT1E1 expression, whereas in the testis, it was virtually undetectable. However, SE tissue concentrations are clearly consistent with the testis as the predominant site of estrogen sulfonation. Results from measurements of estrogen sulfotransferase activity indicate that in the epididymis, SULT1E1 is the relevant enzyme, whereas in the testis, estrogens are sulfonated by a different sulfotransferase with a considerably lower affinity. STS expression and activity was high in the testis (Leydig cells, rete testis epithelium) but also present throughout the epididymis. In the epididymis, SULT1E1 and STS were colocalized in the ductal epithelium, and there was evidence for their apocrine secretion into the ductal lumen. The results suggest that in porcine Leydig cells, SE may be produced as a reservoir to support the levels of bioactive UE via the sulfatase pathway during periods of low activity of the pulsatile testicular steroidogenesis.

Suitability of group-level oral fluid sampling in ruminant populations for lumpy skin disease virus detection

The geographic expansion of Lumpy skin disease (LSD) from the near East into the European Union highlighted again the need for appropriate disease detection tools applicable to animal host populations where access to individual animals is difficult. This is of particular importance considering that the clinical manifestation of LSD is often mild making early disease detection challenging under the above-mentioned conditions. Building on positive experiences of group-level oral fluid sampling for pathogen detection as it is known to work for swine herds and wild boar, the concept was transferred to ruminants. Two groups of six cattle were infected experimentally with Lumpy skin disease virus (LSDV) under controlled conditions. Blood as well as oropharyngeal and nasal swab samples were collected at regular intervals. Group samples were obtained by placing cotton gauze around a salt lick block provided commonly as dietary supplement. Pieces of the gauze with visible signs of manipulation were tested in parallel to samples obtained from individual animals. Genome load analysis by qPCR technology revealed LSDV detection window starting from day 2 post infection until day 28 post infection, the end of the animal trial. At the individual level, detection periods varied between animals and type of sample and included intermitted detection. The accumulative character of the alternative sampling method makes it suitable to detect LSDV DNA at group-level even at times of the infection where a selective sampling of individuals from a group - as normally done in LSD surveillance - would have most likely failed in the detection.

Cis variants identified in F508del complex alleles modulate CFTR channel rescue by small molecules

Molecules correcting the trafficking (correctors) and gating defects (potentiators) of the cystic fibrosis causing mutation c.1521_1523delCTT (p.Phe508del) begin to be a useful treatment for CF patients bearing p.Phe508del. This mutation has been identified in different genetic contexts, alone or in combination with variants in cis. Until now, 21 exonic variants in cis of p.Phe508del have been identified, albeit at a low frequency. The aim of this study was to evaluate their impact on the efficacy of CFTR-directed corrector/potentiator therapy (Orkambi). The analysis by minigene showed that two out of 15 cis variants tested increased exon skipping (c.609C > T and c.2770G > A). Four cis variants were studied functionally in the absence of p.Phe508del, one of which was found to be deleterious for protein maturation c.1399C > T (p.Leu467Phe). In the presence of p.Phe508del, this variant was the only to prevent the response to Orkambi treatment. This study showed that some patients carrying p.Phe508del complex alleles are predicted to poorly respond to corrector/potentiator treatments. Our results underline the importance to validate treatment efficacy in the context of complex alleles.

Downregulation von LH bei der Hündin nach Anwendung des GnRH-Agonisten Buserelin in Implantatform

Gegenstand und Ziel: Darstellung der Downregulation von LH bei der Hündin nach Anwendung eines Slow-Release-GnRH-Implantats mit dem Wirkstoff Buserelin. Material und Methoden: Zur Ausschaltung negativ rückkoppelnder Wirkungen endogener Sexualhormone wurden neun Hündinnen ovariohysterektomiert. Zur Anwendung kam der Wirkstoff Buserelinacetat in Form des Slow-Release-Implantats Profact Depot®, wobei jeweils drei Hündinnen Implantate mit 3,3 mg, 6,6 mg oder 13,2 mg subkutan appliziert wurden. Die Charakterisierung der Verfügbarkeit von LH erfolgte durch punktuelle sowie durch sequenzielle Blutentnahmen über 6-stündige Zeitfenster. Folgende Parameter wurden erfasst: AUC (Area Under the Curve), Basalkonzentration, Anzahl der Pulse und maximale Pulsamplitude. Ergebnisse: Dosisabhängigkeiten waren nicht feststellbar, was darauf hindeutet, dass die niedrigste Dosis bereits maximal wirksam war. Für die weitere Auswertung wurden die Tiere daher zu einer Gruppe zusammengefasst. Ein zunehmend stärker werdender Effekt der Downregulation zeigte sich von der 2. bis zur 26. Woche nach der Implantation, die Wirkdauer lag bei ca. 34 Wochen. Eine Stunde nach der Implantation kam es zu einem signifikanten Anstieg auf fast das Doppelte des Ausgangswerts. Danach blieb das LH-Niveau über weitere 8 Stunden erhöht. Schlussfolgerung: Wie beim Rüden führt Buserelin auch bei der Hündin zu einer Downregulation der LH-Sekretion, der eine initiale, über mehrere Stunden anhaltende erhöhte LH-Freisetzung vorausgeht. Diese muss im Zusammenhang mit den unerwünschten Wirkungen gesehen werden, die bei der Downregulation der Ovarfunktion der Hündin mittels Slow-Release-GnRH-Analoga auftreten. Klinische Relevanz: Die Unterbindung des initialen Anstiegs der LH-Konzentration ist Voraussetzung für eine erfolgreiche Anwendung von Slow-Release-GnRH-Analoga zur Downregulation der Sexualfunktion der Hündin.

Effizienz neurolinguistischer Teletherapie

Die dialogische Online-Telesprachtherapie bietet vor allem für den ländlichen Raum in Zukunft neue Chancen für eine bedarfsgerechte und wohnortnahe Versorgung der Patienten mit Sprach- und Sprechstörungen. Patient und Therapeut agieren in Echtzeit direkt über den Bildschirm miteinander, sodass dem Patienten aufwändige Wege in ein spezialisiertes sprachtherapeutisches Zentrum erspart werden können. Die Telesprachtherapie ermöglicht die Aufrechterhaltung einer sektorenübergreifenden Versorgungskette (supply chain) durch Überbrückung eventueller poststationärer Engpässe.

Grundlagen der Wirkungsweise und sich daraus ergebende klinische Anwendungen von Antigestagenen bei Hund und Katze

Bei Antigestagenen handelt es sich um Wirkstoffe, die kompetitiv zum körpereigenen Progesteron an den nukleären Progesteronrezeptor binden, ohne dass jedoch dadurch die nachfolgende Transkription eingeleitet wird. Damit ergibt sich die grundsätzliche Möglichkeit, durch Anwendung dieser Wirkstoffgruppe zu vorgegebenen Zeitpunkten gezielt die Progesteronwirkung aufzuheben. So kann durch Aufhebung der protektiven Wirkung von Progesteron beim Hund eine Nidationsverhütung, ein Graviditätsabbruch, aber auch die Einleitung einer Geburt erfolgen. Der progesteronbedingte Zervixverschluss lässt sich ebenfalls aufheben, wodurch auch im Fall einer geschlossenen Pyometra erstmals alternativ zur Ovariohysterektomie eine gut verträgliche konservative Therapie möglich ist. Diese für den Hund geltenden Beobachtungen können entsprechend auf die Katze übertragen werden. Bei dieser Tierart stellt die Behandlung der Fibroadenomatose mittels Antigestagen eine weitere neue therapeutische Option dar. Für die Veterinärmedizin steht seit 2004 das den antigestagenen Wirkstoff Aglepriston enthaltende Tierarzneimittel Alizin® zum Graviditätsabbruch bei der Hündin zur Verfügung. Eine darüber hinausgehende Anwendung lässt das Arzneimittelgesetz aufgrund der Möglichkeiten der Umwidmung zu. In einem solchen Fall ist tierärztlicherseits jedoch ein äußerst sorgfältiges und mit der entsprechenden Aufklärung verbundenes Vorgehen notwendig.

Samengewinnung, -konservierung und künstliche Besamung beim Hund

Die künstliche Besamung ist ein inzwischen auch beim Hund etabliertes Verfahren. Zum Einsatz kommen Frischsperma bzw. flüssig- und gefrierkonserviertes Sperma. Das Ejakulat wird durch manuelle Stimulation, bevorzugt in Anwesenheit einer läufigen Hündin, fraktioniert gewonnen, wobei zur Herstellung von flüssig- bzw. gefrierkonserviertem Sperma ausschließlich die spermienreiche Fraktion verwendet werden sollte. Die Verdünnung erfolgt üblicherweise mit einem Tris-Eidotter-Puffer mit einem Antibiotikazusatz bei flüssigkonserviertem Sperma, für die Herstellung von Tiefgefriersperma wird Glyzerin zugesetzt. Entscheidend für den Besamungserfolg ist die Wahl des Besamungszeitpunktes, insbesondere bei Verwendung von Tiefgefriersperma. Vaginalzytologie und Vaginoskopie sollten mit einer Progesteronbestimmung verbunden sein, um den für die Samenübertragung optimalen Bereich um 12 ng/ml Plasma zu definieren. Derzeit kommen vier Inseminationstechniken zur Anwendung: die tief intravaginale Besamung, die transzervikale-intrauterine Besamung mithilfe eines starren Katheters unter transabdominaler Fixation der Zervix, die transzervikale-intrauterine Besamung unter endoskopischer Kontrolle sowie die chirurgische intrauterine Besamung via Laparotomie/Laparoskopie. Bei der Verwendung von Tiefgefriersperma sollte grundsätzlich die intrauterine Samendeponierung angestrebt werden. Als Besamungsdosis werden, unabhängig von der Art des Inseminats, mindestens 150 × 106 vorwärtsbewegliche Spermien empfohlen. Unter optimalen Voraussetzungen können mit der künstlichen Besamung auch beim Einsatz von kryokonserviertem Sperma mit dem natürlichen Deckakt vergleichbare Trächtigkeitsraten und Wurfgrößen erzielt werden.

Prevalence of Stemmer's sign in the general population

Lymphoedema is a disease frequently diagnosed in vascular departments, its origin being primary or secondary after cellulitis or cancer treatment. The prevalence of lower extremity lymphoedema in the general population is largely unknown. The aim of this article is to describe the prevalence of Stemmer's sign as a diagnostic criterium for lymphoedema in an unselected adult German population. Methods: The population for this cross-sectional study was recruited from November 2000 through March 2002 from the general population of the city of Bonn and two surrounding rural communities. 3072 individuals (1145 rural and 1927 urban) could be enrolled in the study. The results of the clinical examination were categorized in four groups: grade 0 normal skin fold at the dorsum of the second toe, grade 1 skin fold enlarged measuring 0.5–1 cm, grade 2 the skin fold >1 cm and grade 3 >1 cm with severe induration or papillomatosis. Results: Among 3055 out of 3072 subjects information on all variables were available. In 15.9% of the population a positive Stemmer sign was found with a slightly higher overall prevalence in women. Most of this group presented as grade 1 Stemmer's sign (14.1%). The more severe grades 2 and 3 were present in 1.8 % of the study population with no clear difference between sexes. We observed a considerably higher prevalence of Stemmer's sign of all grades in the urban population. The prevalence of Stemmer's sign increased with age from 3.2% up to 35.9% in the 70–79 year old population. Prevalence of positive Stemmer's sign was also higher in higher C-stages of the CEAP classification (5.8% in C0 to 100% in C6). Conclusions: The prevalence of lymphoedema in the general population represented by grade 2–3 Stemmer's sign in 1.8% and grade 1 Stemmer's sign in 14% is high. Women have a slightly higher prevalence of positive Stemmer's sign than men. The prevalence of positive Stemmer's sign is associated with age and chronic venous insufficiency.

Prevalence and acceptance of therapy with medical compression stockings

The aim of this study was to assess the prevalence of use of medical compression stockings (MCS) in the general adult population in Germany, to comment the indications for which MCS therapy has been described and the patients’ experience with it. Methods: The survey is based on the Bonn Vein Study. The population of this cross-sectional study was randomly recruited between November 2000 and March 2002 from the registers of residents of the city of Bonn and two rural townships in the area. In total, 3.072 men and women were included in the trial. In addition to clinical examination and duplex-ultrasound, participants were asked whether any phlebological treatment had been carried out due to a leg disorder or disease.. If compression stockings had been worn, we asked for details such as compression class and length of stockings, wearing time, effectiveness, and recognition. Results: In total, 22.9% of people providing information (12.7% of male, 31.0% of female) mentioned having received a specific phlebological treatment in the past. Therapy with compression stockings had the highest prevalence with 14.6% in the general population (7.5% of males, 20.3% of females). The mean age at the first prescription was 45.5 years (SD = 14.3 years). With increasing severity of venous disease, as rated according to the CEAP classification, the prevalence increased from 1% in C0 patients to 82% in C5/C6 patients. Of 450 participants who had used compression stockings in the past, 309 (68.6%) did not wear CS at the time of the survey. The remainder had generally been wearing them on five or more days per week (73.0%) for 8 or more hours per day (89.4%). On average, 71.3% of the participants said that the disease for which MCS were prescribed, had improved as a result of MCS therapy. Improvement concerned a reduction of sensations of swelling (84.2%), of heaviness (89.4%), leg pain after long periods of standing (60.9), and tension in the legs (78.9).

Bluetongue virus serotype 27: Experimental infection of goats, sheep and cattle with three BTV-27 variants reveal atypical characteristics and likely direct contact transmission BTV-27 between goats

Bluetongue virus (BTV) hitherto consisted of 26 recognized serotypes, of which all except BTV-26 are primarily transmitted by certain species of Culicoides biting midges. Three variants of an additional 27th bluetongue virus serotype (BTV-27v01-v03) were recently detected in asymptomatic goats in Corsica, France, 2014-2015. Molecular characterization revealed genetic differences between the three variants. Therefore, in vivo characteristics were investigated by experimental infection of a total of 15 goats, 11 sheep and 4 cattle with any one of the three variants in separated animal trials. In goat trials, BTV-naïve animals of the same species were kept in a facility where direct contact was unhindered. Of the 15 inoculated goats, 13 and 14 animals were found positive for BTV-RNA and antibodies (Ab), respectively, until the end of the experiments. Surprisingly, BTV-Ab levels as measured with ELISA and neutralization test (SNT) were remarkably low in all seropositive goats. Virus isolation from whole-blood was possible at the peak of viremia until 49 dpi. Moreover, detection of BTV-27v02-RNA and Ab in one contact goat indicated that-similar to BTV-26-at least one of three BTV-27 variants may be transmitted by contact between goats. In the field, BTV-27 RNA can be detected up to 6 months in the whole-blood of BTV-27-infected Corsican goats. In contrast, BTV RNA was not detected in the blood of cattle or sheep. In addition, BTV-27 Abs were not detected in cattle and only a transient increase in Ab levels was observed in some sheep. None of the 30 animals showed obvious BT-like clinical signs. In summary, the phenotypes observed for BTV-27v01-v03 phenotypes correspond to a mixture of characteristics known for BTV-25 and 26.

The implications of CFTR structural studies for cystic fibrosis drug development

Development of Cystic Fibrosis Transmembrane conductance Regulator (CFTR) modulators, targeting the root cause of cystic fibrosis (CF), represents a challenge in the era of personalized medicine, as CFTR mutations lead to a variety of phenotypes, which likely require different, specific treatments. CF drug development is also complicated by the need to preserve the right balance between stability and flexibility, required for optimal function of the CFTR protein. In this review, we highlight how structural data can be exploited in this context to understand the molecular mechanisms of disease-associated mutations, to characterize the mechanisms of action of known modulators and to rationalize the search for novel, specific compounds.

New insights into interactions between the nucleotide-binding domain of CFTR and keratin 8

The intermediate filament protein keratin 8 (K8) interacts with the nucleotide-binding domain 1 (NBD1) of the cystic fibrosis (CF) transmembrane regulator (CFTR) with phenylalanine 508 deletion (ΔF508), and this interaction hampers the biogenesis of functional ΔF508-CFTR and its insertion into the plasma membrane. Interruption of this interaction may constitute a new therapeutic target for CF patients bearing the ΔF508 mutation. Here, we aimed to determine the binding surface between these two proteins, to facilitate the design of the interaction inhibitors. To identify the NBD1 fragments perturbed by the ΔF508 mutation, we used hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS) on recombinant wild-type (wt) NBD1 and ΔF508-NBD1 of CFTR. We then performed the same analysis in the presence of a peptide from the K8 head domain, and extended this investigation using bioinformatics procedures and surface plasmon resonance, which revealed regions affected by the peptide binding in both wt-NBD1 and ΔF508-NBD1. Finally, we performed HDX-MS analysis of the NBD1 molecules and full-length K8, revealing hydrogen-bonding network changes accompanying complex formation. In conclusion, we have localized a region in the head segment of K8 that participates in its binding to NBD1. Our data also confirm the stronger binding of K8 to ΔF508-NBD1, which is supported by an additional binding site located in the vicinity of the ΔF508 mutation in NBD1.

Simple, quick and cost-efficient: A universal RT-PCR and sequencing strategy for genomic characterisation of foot-and-mouth disease viruses

Foot-and-mouth disease (FMD) is a major contributor to poverty and food insecurity in Africa and Asia, and it is one of the biggest threats to agriculture in highly developed countries. As FMD is extremely contagious, strategies for its prevention, early detection, and the immediate characterisation of outbreak strains are of great importance. The generation of whole-genome sequences enables phylogenetic characterisation, the epidemiological tracing of virus transmission pathways and is supportive in disease control strategies. This study describes the development and validation of a rapid, universal and cost-efficient RT-PCR system to generate genome sequences of FMDV, reaching from the IRES to the end of the open reading frame. The method was evaluated using twelve different virus strains covering all seven serotypes of FMDV. Additionally, samples from experimentally infected animals were tested to mimic diagnostic field samples. All primer pairs showed a robust amplification with a high sensitivity for all serotypes. In summary, the described assay is suitable for the generation of FMDV sequences from all serotypes to allow immediate phylogenetic analysis, detailed genotyping and molecular epidemiology.

Early life travelling does not increase risk of atopic outcomes until 15 years: results from GINIplus and LISAplus

BACKGROUND

Westernized lifestyle has been blamed for allergy epidemics. One of its characteristics is increased distances and frequency of travelling from early life onwards. Early life travelling to places which substantially differ from home environment in terms of climate, vegetation and food could increase the exposure to further unknown allergens and hence promote the development of allergies, but no epidemiological study has investigated this speculation.

METHODS

Detailed data on travelling during the first 2 years of life as well as a range of atopic outcomes along with potential confounders up to age 15 years were collected prospectively within two large population-based multicentre German birth cohorts - GINIplus and LISAplus. Farthest travelling destination (within Germany; middle/northern/eastern Europe; southern Europe; outside Europe), total number of trips and their combination were considered as exposures. Six atopic outcomes were used: (1) doctor-diagnosed asthma, (2) doctor-diagnosed allergic rhinitis, (3) nose and eye symptoms, (4) sensitization to food allergens, (5) sensitization to indoor and (6) outdoor inhalant allergens. Longitudinal associations between each exposure and health outcome pair were analysed using generalized estimation equations (GEEs).

RESULTS

The results of our longitudinal analyses of 5674 subjects do not support the research hypothesis that travelling abroad to different regions in Europe or beyond Europe and frequency of travelling increase prevalence of doctor-diagnosed asthma and allergic rhinitis, nose and eye symptoms and allergic sensitization up to 15 years of age. Furthermore, there was no indication of age-varying effects.

CONCLUSIONS

Early life travelling does not seem to increase risk of atopic outcomes. Nevertheless, as we could not account for the type of visited environment or length of stay, these first findings should be interpreted with caution.

Functional defect of variants in the adenosine triphosphate-binding sites of ABCB4 and their rescue by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor (VX-770)

ABCB4 (MDR3) is an adenosine triphosphate (ATP)-binding cassette (ABC) transporter expressed at the canalicular membrane of hepatocytes, where it mediates phosphatidylcholine (PC) secretion. Variations in the ABCB4 gene are responsible for several biliary diseases, including progressive familial intrahepatic cholestasis type 3 (PFIC3), a rare disease that can be lethal in the absence of liver transplantation. In this study, we investigated the effect and potential rescue of ABCB4 missense variations that reside in the highly conserved motifs of ABC transporters, involved in ATP binding. Five disease-causing variations in these motifs have been identified in ABCB4 (G535D, G536R, S1076C, S1176L, and G1178S), three of which are homologous to the gating mutations of cystic fibrosis transmembrane conductance regulator (CFTR or ABCC7; i.e., G551D, S1251N, and G1349D), that were previously shown to be function defective and corrected by ivacaftor (VX-770; Kalydeco), a clinically approved CFTR potentiator. Three-dimensional structural modeling predicted that all five ABCB4 variants would disrupt critical interactions in the binding of ATP and thereby impair ATP-induced nucleotide-binding domain dimerization and ABCB4 function. This prediction was confirmed by expression in cell models, which showed that the ABCB4 mutants were normally processed and targeted to the plasma membrane, whereas their PC secretion activity was dramatically decreased. As also hypothesized on the basis of molecular modeling, PC secretion activity of the mutants was rescued by the CFTR potentiator, ivacaftor (VX-770).

CONCLUSION

Disease-causing variations in the ATP-binding sites of ABCB4 cause defects in PC secretion, which can be rescued by ivacaftor. These results provide the first experimental evidence that ivacaftor is a potential therapy for selected patients who harbor mutations in the ATP-binding sites of ABCB4. (Hepatology 2017;65:560-570).

Molecular modelling and molecular dynamics of CFTR

The cystic fibrosis transmembrane conductance regulator (CFTR) protein is a member of the ATP-binding cassette (ABC) transporter superfamily that functions as an ATP-gated channel. Considerable progress has been made over the last years in the understanding of the molecular basis of the CFTR functions, as well as dysfunctions causing the common genetic disease cystic fibrosis (CF). This review provides a global overview of the theoretical studies that have been performed so far, especially molecular modelling and molecular dynamics (MD) simulations. A special emphasis is placed on the CFTR-specific evolution of an ABC transporter framework towards a channel function, as well as on the understanding of the effects of disease-causing mutations and their specific modulation. This in silico work should help structure-based drug discovery and design, with a view to develop CFTR-specific pharmacotherapeutic approaches for the treatment of CF in the context of precision medicine.

Residential greenness is differentially associated with childhood allergic rhinitis and aeroallergen sensitization in seven birth cohorts

BACKGROUND

The prevalence of allergic rhinitis is high, but the role of environmental factors remains unclear. We examined cohort-specific and combined associations of residential greenness with allergic rhinitis and aeroallergen sensitization based on individual data from Swedish (BAMSE), Australian (MACS), Dutch (PIAMA), Canadian (CAPPS and SAGE), and German (GINIplus and LISAplus) birth cohorts (n = 13 016).

METHODS

Allergic rhinitis (doctor diagnosis/symptoms) and aeroallergen sensitization were assessed in children aged 6-8 years in six cohorts and 10-12 years in five cohorts. Residential greenness was defined as the mean Normalized Difference Vegetation Index (NDVI) in a 500-m buffer around the home address at the time of health assessment. Cohort-specific associations per 0.2 unit increase in NDVI were assessed using logistic regression models and combined in a random-effects meta-analysis.

RESULTS

Greenness in a 500-m buffer was positively associated with allergic rhinitis at 6-8 years in BAMSE (odds ratio = 1.42, 95% confidence interval [1.13, 1.79]) and GINI/LISA South (1.69 [1.19, 2.41]) but inversely associated in GINI/LISA North (0.61 [0.36, 1.01]) and PIAMA (0.67 [0.47, 0.95]). Effect estimates in CAPPS and SAGE were also conflicting but not significant (0.63 [0.32, 1.24] and 1.31 [0.81, 2.12], respectively). All meta-analyses were nonsignificant. Results were similar for aeroallergen sensitization at 6-8 years and both outcomes at 10-12 years. Stratification by NO2 concentrations, population density, an urban vs rural marker, and moving did not reveal consistent trends within subgroups.

CONCLUSION

Although residential greenness appears to be associated with childhood allergic rhinitis and aeroallergen sensitization, the effect direction varies by location.

High Prevalence of Highly Variable Atypical Porcine Pestiviruses Found in Germany

Recently, a novel atypical porcine pestivirus (APPV) with significant distribution was described in the USA. Subsequent screening of the German pig sector showed a high prevalence of APPV with high variability among strains. First indication of a cell culture isolate is provided which will allow further investigations like pathogenesis studies.

Self-Catalyzed Growth of Vertically Aligned InN Nanorods by Metal-Organic Vapor Phase Epitaxy

Vertically aligned hexagonal InN nanorods were grown mask-free by conventional metal-organic vapor phase epitaxy without any foreign catalyst. The In droplets on top of the nanorods indicate a self-catalytic vapor-liquid-solid growth mode. A systematic study on important growth parameters has been carried out for the optimization of nanorod morphology. The nanorod N-polarity, induced by high temperature nitridation of the sapphire substrate, is necessary to achieve vertical growth. Hydrogen, usually inapplicable during InN growth due to formation of metallic indium, and silane are needed to enhance the aspect ratio and to reduce parasitic deposition beside the nanorods on the sapphire surface. The results reveal many similarities between InN and GaN nanorod growth showing that the process despite the large difference in growth temperature is similar. Transmission electron microscopy, spatially resolved energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been performed to analyze the structural properties. Spatially resolved cathodoluminescence investigations are carried out to verify the optical activity of the InN nanorods. The InN nanorods are expected to be the material of choice for high-efficiency hot carrier solar cells.