Correlating fluorescence microscopy, optical and magnetic tweezers to study single chiral biopolymers such as DNA

Biopolymer topology is critical for determining interactions inside cell environments, exemplified by DNA where its response to mechanical perturbation is as important as biochemical properties to its cellular roles. The dynamic structures of chiral biopolymers exhibit complex dependence with extension and torsion, however the physical mechanisms underpinning the emergence of structural motifs upon physiological twisting and stretching are poorly understood due to technological limitations in correlating force, torque and spatial localization information. We present COMBI-Tweez (Combined Optical and Magnetic BIomolecule TWEEZers), a transformative tool that overcomes these challenges by integrating optical trapping, time-resolved electromagnetic tweezers, and fluorescence microscopy, demonstrated on single DNA molecules, that can controllably form and visualise higher order structural motifs including plectonemes. This technology combined with cutting-edge MD simulations provides quantitative insight into complex dynamic structures relevant to DNA cellular processes and can be adapted to study a range of filamentous biopolymers.

Sticker-and-spacer model for amyloid beta condensation and fibrillation

A major pathogenic hallmark of Alzheimer's disease is the presence of neurotoxic plaques composed of amyloid beta (Aβ) peptides in patients' brains. The pathway of plaque formation remains elusive, though some clues appear to lie in the dominant presence of Aβ_{1 − 42} in these plaques despite Aβ₁₋₄₀ making up approximately 90% of the Aβ pool. We hypothesize that this asymmetry is driven by the hydrophobicity of the two extra amino acids that are incorporated in Aβ₁₋₄₂. To investigate this hypothesis at the level of single molecules, we have developed a molecular “sticker-and-spacer lattice model” of unfolded Aβ. The model protein has a single sticker that may reversibly dimerise and elongate into semi-flexible linear chains. The growth is hampered by excluded-volume interactions that are encoded by the hydrophilic spacers but are rendered cooperative by the attractive interactions of hydrophobic spacers. For sufficiently strong hydrophobicity, the chains undergo liquid-liquid phase-separation (LLPS) into condensates that facilitate the nucleation of fibers. We find that a small fraction of Aβ₁₋₄₀ in a mixture of Aβ₁₋₄₀ and Aβ₁₋₄₂ shifts the critical concentration for LLPS to lower values. This study provides theoretical support for the hypothesis that LLPS condensates act as a precursor for aggregation and provides an explanation for the Aβ₁₋₄₂-enrichment of aggregates in terms of hydrophobic interactions.

Tween-20 Induces the Structural Remodeling of Single Lipid Vesicles

The solubilization of lipid membranes by Tween-20 is crucial for a number of biotechnological applications, but the mechanistic details remain elusive. Evidence from ensemble assays supports a solubilization model that encompasses surfactant association with the membrane and the release of mixed micelles to solution, but whether this process also involves intermediate transitions between regimes is unanswered. In search of mechanistic origins, increasing focus is placed on identifying Tween-20 interactions with controllable membrane mimetics. Here, we employed ultrasensitive biosensing approaches, including single-vesicle spectroscopy based on fluorescence and energy transfer from membrane-encapsulated molecules, to interrogate interactions between Tween-20 and submicrometer-sized vesicles below the optical diffraction limit. We discovered that Tween-20, even at concentrations below the critical micellar concentration, triggers stepwise and phase-dependent structural remodeling events, including permeabilization and swelling, in both freely diffusing and surface-tethered vesicles, highlighting the substantial impact the surfactant has on vesicle conformation and stability prior to lysis.

Membraneless organelles formed by liquid-liquid phase separation increase bacterial fitness

Liquid-liquid phase separation is emerging as a crucial phenomenon in several fundamental cell processes. A range of eukaryotic systems exhibit liquid condensates. However, their function in bacteria, which, in general, lack membrane-bound compartments, remains less clear. Here, we used high-resolution optical microscopy to observe single bacterial aggresomes, nanostructured intracellular assemblies of proteins, to undercover their role in cell stress. We find that proteins inside aggresomes are mobile and undergo dynamic turnover, consistent with a liquid state. Our observations are in quantitative agreement with phase-separated liquid droplet formation driven by interacting proteins under thermal equilibrium that nucleate following diffusive collisions in the cytoplasm. We have found aggresomes in multiple species of bacteria and show that these emergent, metastable liquid-structured protein assemblies increase bacterial fitness by enabling cells to tolerate environmental stresses.

Cryoballoon ablation of atrial fibrillation in low and medium volume hospitals – experiences of the German REGIONAL registry

Background

Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) has become an established and widespread procedure for the treatment of symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI at low and medium volume hospitals is unknown.

Aim

To determine safety and acute efficacy of PVI using CBA performed at community hospitals with limited annual case numbers.

Methods

This registry study prospectively included 1004 consecutive patients who underwent PVI with CBA for symptomatic paroxysmal (n=563) or persistent AF (n=441) between 01/2019 and 09/2020 at 20 community hospitals (each performing <100 PVI/year). Qualifying criteria for participating hospitals were an experience of performing CBA for at least 1 year and a minimum of 50 CBA performed up to the start of the registry. All CBA procedures were performed according to the individual local standards of each hospital. Procedural data, acute efficacy and complications were determined.

Results

The mean annual number of CBA procedures performed was 59±26/hospital, the mean annual number of PVI performed regardless of the method used was 70±26/center. 8/20 hospitals performed CBA only. There were 22 operators (1,1/center), in 12/20 hospitals CBA was performed by an operator being board certified in invasive electrophysiology. 10/20 hospitals included <60 patients/center (n=381), the centers enrolling >60 patients/hospital included a total of 623 pts (62%). Mean procedure time was 90.1±31.6 min, mean fluoroscopy time was 19.2±11.4 min. Isolation of all pulmonary veins could be achieved in 97.9% of patients. Not achieving the goal of “all veins isolated” in a respective patient was mainly due to early termination of CBA procedure due to phrenic nerve palsy.

Major complications occurred in 1,2% of patients: no in-hospital death (0%), clinical stroke in 2 patients (0.2%), pericardial effusion requiring pericardial drainage in 2 patients (0,2%), vascular complications needing vascular surgery and/or blood transfusion in 2 patients (0,2%), phrenic nerve palsy persisting up to hospital discharge in 6 patients (0,6%). Minor complications occurred in 7,5% of patients: pericardial effusion with no need of intervention in 0,4%, access site complications with no need for therapeutic intervention or prolonged in-hospital stay in 2,1% (mainly superficial hematoma) and phrenic nerve palsy resolving before discharge in 4,2%.

No significant difference in the number of complications could be found when testing for numbers of enrolled patients (> or < than 60/hospital) or regarding the board certification status of the operator.

Conclusions

PVI for paroxysmal or persistent AF using CBA can be performed at community hospitals with high acute efficacy and low complication rates despite low and moderate annual procedure numbers.

Funding Acknowledgement

Type of funding sources: None.

Safety and efficacy of cryoballoon-ablation for atrial fibrillation performed at local hospitals: results of the german register on cryoballoon-ablation in local hospitals (REGIONAL)

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

REGIONAL

Background

Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) has become an established procedure for the treatment of symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI at community hospitals with low to moderate case numbers is unknown.

Aim

To determine safety and efficacy of PVI using CBA performed at community hospitals with limited annual case numbers.

Methods

1004 PVI performed consecutively between 01/2019 and 09/2020 at 20 community hospitals (each <100 PVI using CBA/year) for symptomatic paroxysmal AF (n = 563) or persistentAF (n= 441) were included in this registry. CBA was performed considering local standards. Procedural data, efficacy and complications were determined.

Results

Mean number of PVI using CBA/year was 59 ± 26. Mean procedure time was 90.1 ± 31.6 min and mean fluoroscopy time was 19.2 ± 11.4 min. Isolation of all pulmonary veins could be achieved in 97.9% of patients, early termination of CBA due to phrenic nerve palsy was the most frequent reason for incomplete isolation. There was no in-hospital death. 2 patients (0.2%) suffered a clinical stroke. Pericardial effusion occurred in 6 patients (0.6%), 2 of them (0.2%) required pericardial drainage. Vascular complications occurred in 24 patients (2.4%), in 2 of these patients (0.2%) vascular surgery was required. In 48 patients (4.8 %) phrenic nerve palsy was noticed which persisted up to hospital discharge in 6 patients (0.6%).

Conclusions

PVI for paroxysmal or persistent AF using CBA can be performed at community hospitals with high efficacy and low complication rates despite low to moderate annual procedure numbers.

Stretching of Bombyx mori Silk Protein in Flow

The flow-induced self-assembly of entangled Bombyx mori silk proteins is hypothesised to be aided by the ‘registration’ of aligned protein chains using intermolecularly interacting ‘sticky’ patches. This suggests that upon chain alignment, a hierarchical network forms that collectively stretches and induces nucleation in a precisely controlled way. Through the lens of polymer physics, we argue that if all chains would stretch to a similar extent, a clear correlation length of the stickers in the direction of the flow emerges, which may indeed favour such a registration effect. Through simulations in both extensional flow and shear, we show that there is, on the other hand, a very broad distribution of protein–chain stretch, which suggests the registration of proteins is not directly coupled to the applied strain, but may be a slow statistical process. This qualitative prediction seems to be consistent with the large strains (i.e., at long time scales) required to induce gelation in our rheological measurements under constant shear. We discuss our perspective of how the flow-induced self-assembly of silk may be addressed by new experiments and model development.

Power Law Stretching of Associating Polymers in Steady-State Extensional Flow

We present a tube model for the Brownian dynamics of associating polymers in extensional flow. In linear response, the model confirms the analytical predictions for the sticky diffusivity by Leibler-Rubinstein-Colby theory. Although a single-mode Doi-Edwards-Marrucci-Grizzuti approximation accurately describes the transient stretching of the polymers above a "sticky" Weissenberg number (product of the strain rate with the sticky-Rouse time), the preaveraged model fails to capture a remarkable development of a power law distribution of stretch in steady-state extensional flow: while the mean stretch is finite, the fluctuations in stretch may diverge. We present an analytical model that shows how strong stochastic forcing drives the long tail of the distribution, gives rise to rare events of reaching a threshold stretch, and constitutes a framework within which nucleation rates of flow-induced crystallization may be understood in systems of associating polymers under flow. The model also exemplifies a wide class of driven systems possessing strong, and scaling, fluctuations.

Breastfeeding is associated with reduced risk of multiple sclerosis in males, predominantly among HLA-DRB1*15:01 carriers

BACKGROUND

Breastfeeding as an infant appears protective against later development of some autoimmune diseases, but research into its influence on multiple sclerosis (MS) risk has yielded inconclusive results.

OBJECTIVE

We investigated the possible impact of breastfeeding on MS risk.

METHODS

We used two population-based case-control studies comprising 3670 cases and 6737 matched controls. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for association between MS and exposure to prolonged breastfeeding (4 months or longer) versus reduced breastfeeding (less than 4 months). A meta-analysis of case-control studies that assessed the impact of breastfeeding on MS risk among women and men was conducted.

RESULTS

Prolonged breastfeeding was associated with reduced MS risk among men (OR 0.7, 95% CI 0.5-0.9) but not among women (OR 0.9, 95% CI 0.8-1.1). Among men, a synergistic effect was observed between HLA-DRB1*15:01 carrier status and reduced breastfeeding.

CONCLUSIONS

Findings from the current study add to accumulating evidence that breastfeeding may be a modifiable protective factor for reducing the risk of MS in offspring. When possible, mothers should be supported to breastfeed their infants; however, the mechanism of a sex-specific biologic effect of breastfeeding on MS risk is unclear.

Silk Protein Solution: A Natural Example of Sticky Reptation

Silk is one of the most intriguing examples of biomolecular self-assembly, yet little is understood of molecular mechanisms behind the flow behavior generating these complex high-performance fibers. This work applies the polymer physics of entangled solution rheology to present a first microphysical understanding of silk in the linear viscoelastic regime. We show that silk solutions can be approximated as reptating polymers with "sticky" calcium bridges whose strength can be controlled through the potassium concentration. This approach provides a new window into critical microstructural parameters, in particular identifying the mechanism by which potassium and calcium ions are recruited as a powerful viscosity control in silk. Our model constitutes a viable starting point to understand not only the "flow-induced self-assembly" of silk fibers but also a broader range of phenomena in the emergent field of material-focused synthetic biology.

Morphology formation in binary mixtures upon gradual destabilisation

Spontaneous liquid-liquid phase separation is commonly understood in terms of phenomenological mean-field theories. These theories correctly predict the structural features of the fluid at sufficiently long time scales and wavelengths. However, these conditions are not met in various examples in biology and materials science where the mixture is slowly destabilised, and phase separation is strongly affected by critical thermal fluctuations. We propose a mechanism of pretransitional structuring of a mixture that approaches the miscibility gap and predict scaling relations that describe how the characteristic feature size of the emerging morphology decreases with an increasing quench rate. These predictions quantitatively agree with our kinetic Monte Carlo and molecular dynamics simulations of a phase-separating binary mixture, as well as with previously reported experimental observations. We discuss how these predictions are affected by non-conserved order parameters (e.g., due to chemical reactions or alignment of liquid-crystalline molecules), hydrodynamics and active transport.

The Complex Spine in Children with Spinal Muscular Atrophy: The Transforaminal Approach-A Transformative Technique

BACKGROUND AND PURPOSE

Spinal muscular atrophy, a genetic disease resulting in loss of motor function, presents from in utero to adulthood. Depending on progression and secondary scoliosis, spinal stabilization may be necessary. When planning intrathecal access in these patients, spinal anatomy is the most important factor. Therefore, when planning intrathecal nusinersen injections, we subdivided patients with spinal muscular atrophy into simple-versus-complex spine subgroups. Our purpose was to present our experience with our first 42 transforaminal intrathecal nusinersen injections.

MATERIALS AND METHODS

We reviewed 31 consecutive patients with spinal muscular atrophy types 1-3 who presented for intrathecal nusinersen injections from March 2017 to September 2018. Nine children had complex spines (ie, spinal instrumentation and/or fusion) and required preprocedural imaging for route planning for subarachnoid space access via transforaminal or cervical approaches.

RESULTS

A total of 164 intrathecal nusinersen injections were performed in 31 children 4-226 months of age, with 100% technical success in accessing the subarachnoid space. Nine patients with complex spinal anatomy underwent 45 intrathecal nusinersen injections; 42 of 45 procedures were performed via a transforaminal approach with the remaining 3 via cervical techniques. There were no complications.

CONCLUSIONS

Our initial experience has resulted in a protocol-driven approach based on simple or complex spinal anatomy. Patients with simple spines do not need preprocedural imaging or imaging-guided intrathecal nusinersen injections. In contrast, the complex spine subgroup requires preprocedural imaging for route planning and imaging guidance for therapy, with the primary approach being the transforaminal approach for intrathecal nusinersen injections.

Establishment of a Mucin Secreting Cell Line Cx-03 from an Uterine Carcino Sarcoma

PURPOSE

The identification of novel cell lines which combine the most important properties of mucosal membranes in terms of drug absorption, transmembrane transport and mucus secretion can help to establish improved and meaningful test systems for pharmacological and infectiological studies.

METHODS

We have established a novel mucus secreting tumor cell line (Cx-03) derived from a female patient who underwent radical hysterectomy after diagnosis of a large malignant carcino sarcoma (Muellerian mixed tumor). Via xenotransplantation in SCID beige mice, recultivation and subcloning a stable cell line was established from primary tumor cells.

RESULTS

Human origin and novelty of the cell line was determined by karyotype analysis and STR fingerprint. During growth cells produce considerable amounts of a PAS positive viscoelastic mucus. Immunostaining revealed expression of mucins and the mucin modifier CLCA1. We demonstrate in initial electrophysiological experiments that confluent, polarized monolayers of Cx-03 are formed (on PCF-filter supports) that exhibit stable electrical resistance (> 600 Ω cm²). Confluent Cx-03 monolayers express barrier-forming tight junction proteins claudin-1 and -4 which co-localize with zonula occludens protein-1 (ZO-1) at cell-cell contacts.

CONCLUSIONS

Mucus secretion is a rare property among mammalian cell lines. In combination with its ability to form polarized monolayers Cx-03 might contribute as a novel cell based model for drug absorption, transport and barrier studies.

Ligand-regulated oligomerisation of allosterically interacting proteins

The binding of ligands to distinct sites at proteins or at protein clusters is often cooperative or anti-cooperative due to allosteric signalling between those sites. The allostery is usually attributed to a configurational change of the proteins from a relaxed to a configurationally different tense state. Alternatively, as originally proposed by Cooper and Dryden, a tense state may be achieved by merely restricting the thermal vibrations of the protein around its mean configuration. In this work, we provide theoretical tools to investigate fluctuation allostery using cooling and titration experiments in which ligands regulate dimerisation, or ring or chain formation. We discuss in detail how ligands may regulate the supramolecular (co)polymerisation of liganded and unliganded proteins.

The 'allosteron' model for entropic allostery of self-assembly

Using the simple 'allosteron' model, we show that it is possible, in principle, to elicit pathways by which fluctuation allostery affects self-assembly of protein complexes. We treat the cases of (i) protein fibrils and nucleation, (ii) n-mer protein complexes, and (iii) weakly attractive allosteric interactions in protein-like soft nanoscale objects that can be tuned to define exclusive self-associating families.This article is part of a discussion meeting issue 'Allostery and molecular machines'.

Reduced longitudinal cardiac strain in asthma patients

OBJECTIVE

There is limited knowledge about the potential relationship between asthma and heart function. Aim of our present study was to examine if asthma may be associated with manifest or subclinical heart dysfunction.

METHODS

Seventy-two allergic mild-to-moderate and severe asthma patients and 20 matched controls were enrolled in the study. Depending on the anti-asthmatic therapy, four subgroups of asthma patients were created: patients under long-acting beta2-agonists (LABA) and inhaled cortisone without oral cortisone treatment with (1a) versus without (1b) additional omalizumab therapy; patients with LABA, inhaled cortisone and omalizumab treatment with (2a) versus without (2b) oral cortisone. Standard echocardiographic parameters as well as global longitudinal left and right ventricular strains as determined by ultrasound-based speckle-tracking method were evaluated. Furthermore, NT-pro-brain natriuretic peptide (NT-pro-BNP), immunoglobulin E (IgE), C-reactive protein (CRP), and blood count were assessed in asthma and control groups.

RESULTS

There were no relevant differences in standard echocardiographic measures between both asthma groups and the control collective. Longitudinal left ventricular strain values were reduced significantly in severe and mild-to-moderate asthma groups (-12.91 ± 0.84% and -13.92 ± 1.55%, respectively), whereas longitudinal right ventricular strain values were additionally relevantly decreased in severe asthma (-10.35 ± 1.04%) compared to the control (-16.55 ± 0.49% and -18.48 ± 1.90%, respectively). Cardiac strains were similar in subgroups 1a and 1b. In contrast, patients from subgroup 2a presented reduced heart strains and decreased lung function compared to those from 2b. CRP, IgE, and eosinophils were significantly increased in asthma versus control individuals.

CONCLUSIONS

Allergic asthma, especially severe asthma is associated with subclinical impaired left and right ventricular function as determined by speckle-tracking analysis.

Structuring of Fluid Adlayers upon Ongoing Unimolecular Adsorption

Fluids with spatial density variations of single or mixed molecules play a key role in biophysics, soft matter, and materials science. The fluid structures usually form via spinodal decomposition or nucleation following an instantaneous destabilization of the initially disordered fluid. However, in practice, an instantaneous quench is often not viable, and the rate of destabilization may be gradual rather than instantaneous. In this work we show that the commonly used phenomenological descriptions of fluid structuring are inadequate under these conditions. We come to that conclusion in the context of surface catalysis, where we employ kinetic Monte Carlo simulations to describe the unimolecular adsorption of gaseous molecules onto a metal surface. The adsorbates diffuse at the surface and, as a consequence of lateral interactions and due to an ongoing increase of the surface coverage, phase separate into coexisting low- and high-density regions. The typical size of these regions turns out to depend much more strongly on the rate of adsorption than predicted from recently reported phenomenological models. We discuss how this finding contributes to the fundamental understanding of the crossover from liquid-liquid to liquid-solid demixing of solution-cast polymer blends.

Dynamic Surface Enrichment in Drying Thin-Film Binary Polymer Solutions

Solution-cast, thin-film polymer composites find a wide range of applications, such as in the photoactive layer of organic solar cells. The performance of this layer crucially relies on its phase-separated morphology. Efficient charge-carrier extraction requires each of the components to preferentially wet one of the two electrodes. It is often presumed that the experimentally observed surface enrichment required for this is caused by specific interactions of the active ingredients with each surface. By applying a generalized diffusion model, we find the dynamics to also play an important role in determining which component accumulates at which surface. We show that for sufficiently fast evaporation the component with the smallest cooperative diffusivity accumulates at the free interface. Counterintuitively, depending on the interactions between the various components, this may be the smaller solute. Our comprehensive numerical and analytical study provides a tool to predict and control phase-separated morphologies in thin-film polymer composites.

Atherosclerotic Vessel Changes in Sarcoidosis

Sarcoidosis is a systemic granulomatous disease. Atherosclerosis is a chronic inflammatory vessel disease. The aim of our present study was to investigate whether sarcoidosis could be associated with increased risk of atherosclerotic vessel changes. Angiological analysis and blood tests were performed in 71 sarcoidosis patients and 12 matched controls in this prospective cross-sectional study. Specifically, angiological measurements comprised ankle brachial index (ABI), central pulse wave velocity (cPWV), pulse wave index (PWI), and duplex sonography of central and peripheral arteries. Sarcoidosis activity markers (angiotensin converting enzyme, soluble interleukin-2 receptor) and cardiovascular risk parameters such as cholesterol, lipoprotein(a), C-reactive protein, interleukin 6, fibrinogen, d-dimer, and blood count were analyzed in blood. We found no relevant differences in ABI, cPWV, and plaque burden between the sarcoidosis and control groups (1.10 ± 0.02 vs. 1.10 ± 0.02, 6.7 ± 0.5 vs. 6.1 ± 1.2, 53.7 % vs. 54.5 %, respectively). However, PWI was significantly higher in sarcoidosis patients (146.2 ± 6.8) compared with controls (104.9 ± 8.8), irrespectively of the activity of sarcoidosis and immunosuppressive medication. Except for increased lipoprotein(a) and d-dimer in sarcoidosis, the remaining cardiovascular markers were similar in both groups. We conclude that sarcoidosis is associated with increased pulse wave index, which may indicate an early stage of atherosclerosis.

Impaired Vascular Function in Sarcoidosis Patients

A common feature of sarcoidosis and atherosclerosis is a chronic systemic inflammatory reaction. Our hypothesis was that sarcoidosis may negatively influence the vessel status. We addressed the issue by examining preatherosclerotic vascular alternations using an ultrasound-based speckle-tracking method in 72 sarcoidosis patients and 15 matched controls. To find potential factors which may have a deleterious influence on arterial performance, different subgroups of sarcoidosis, such as sarcoidosis with or without cortisone therapy, pulmonary sarcoidosis in early and advanced stages, pulmonary sarcoidosis alone or combined with extrapulmonary sarcoidosis, and sarcoidosis with or without elevated blood levels of angiotensin converting enzyme (ACE)/soluble interleukin 2 receptor (sIL-2R) were investigated. We found in the general collective of sarcoidosis patients that circumferential strain (2.68 ± 0.19%), circumferential strain rate (0.21 ± 0.01 1/s), and radial displacement (0.10 ± 0.01 mm) were significantly decreased compared to controls (3.77 ± 0.35%, 0.28 ± 0.02 1/s, and 0.14 ± 0.02 mm, respectively). Vascular strains were more impaired in patients with cortisone therapy, pulmonary sarcoidosis in stages III-IV, and in pulmonary sarcoidosis accompanied by extrapulmonary involvement. The level of ACE/sIL-2R had no relevant influence on the angiological parameters. In conclusion, sarcoidosis is associated with increased vascular stiffness. Cortisone therapy and advanced stages of pulmonary sarcoidosis with extrapulmonary manifestations may account for the impaired vascular function in this patient collective.

Clostridium perfringens: a rare cause of spondylodiscitis case report and review of the literature

Presented is a case of a 64-year old male with a unique and yet unreported case of a spondylodiscitis caused by Clostridium perfringens. Becoming symptomatic with massive neurological deficits. Computed tomography (CT) revealed typical signs of spondylodiscitis involving the vertebral body L5 with extensive vacuum phenomenon.

The Kaiser Permanente Northern California research program on genes, environment, and health (RPGEH) pregnancy cohort: study design, methodology and baseline characteristics

Background

Exposures during the prenatal period may have lasting effects on maternal and child health outcomes. To better understand the effects of the in utero environment on children’s short- and long-term health, large representative pregnancy cohorts with comprehensive information on a broad range of environmental influences (including biological and behavioral) and the ability to link to prenatal, child and maternal health outcomes are needed. The Research Program on Genes, Environment and Health (RPGEH) pregnancy cohort at Kaiser Permanente Northern California (KPNC) was established to create a resource for conducting research to better understand factors influencing women’s and children’s health. Recruitment is integrated into routine clinical prenatal care at KPNC, an integrated health care delivery system. We detail the study design, data collection, and methodologies for establishing this cohort. We also describe the baseline characteristics and the cohort’s representativeness of the underlying pregnant population in KPNC.

Methods

While recruitment is ongoing, as of October 2014, the RPGEH pregnancy cohort included 16,977 pregnancies (53 % from racial and ethnic minorities). RPGEH pregnancy cohort participants consented to have blood samples obtained in the first trimester (mean gestational age 9.1 weeks ± 4.2 SD) and second trimester (mean gestational age 18.1 weeks ± 5.5 SD) to be stored for future use. Women were invited to complete a questionnaire on health history and lifestyle. Information on women’s clinical and health assessments before, during and after pregnancy and women and children’s health outcomes are available in the health system’s electronic health records, which also allows long-term follow-up.

Discussion

This large, racially- and ethnically-diverse cohort of pregnancies with prenatal biospecimens and clinical data is a valuable resource for future studies on in utero environmental exposures and maternal and child perinatal and long term health outcomes. The baseline characteristics of RPGEH Pregnancy Cohort demonstrate that it is highly representative of the underlying population living in the broader community in Northern California.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1150-2) contains supplementary material, which is available to authorized users.

The Kissing Balloons Technique

Whereas dilatation of a single stenosis of the main renal artery is a routine intervention, a narrowing of the renal artery at its bifurcation extending into the branch arteries poses a more complex problem. The procedural risks of renal artery dilatation are compounded by the danger of occlusion of one of the branch arteries during maneuvers to dilate the other. Long-term results of surgical vascular reconstruction at a renal artery bifurcation are not satisfactory. Untreated, these stenoses lead to intractable hypertension and impairment or loss of renal function. We present a patient with hypertension and impaired function of the right kidney on account of a renal arterial bifurcation stenosis. Using a bilateral transfemoral arterial approach 2 balloon catheters were simultaneously placed into the origins of the renal artery branches and both arteries were successfully dilated by the kissing balloons technique. This method provides an elegant alternative to difficult surgery to save an endangered kidney.

CC chemokine receptor 10 cell surface presentation in melanocytes is regulated by the novel interaction partner S100A10

The superfamily of G-protein-coupled receptors (GPCR) conveys signals in response to various endogenous and exogenous stimuli. Consequently, GPCRs are the most important drug targets. CCR10, the receptor for the chemokines CCL27/CTACK and CCL28/MEC, belongs to the chemokine receptor subfamily of GPCRs and is thought to function in immune responses and tumour progression. However, there is only limited information on the intracellular regulation of CCR10. We find that S100A10, a member of the S100 family of Ca(2+) binding proteins, binds directly to the C-terminal cytoplasmic tail of CCR10 and that this interaction regulates the CCR10 cell surface presentation. This identifies S100A10 as a novel interaction partner and regulator of CCR10 that might serve as a target for therapeutic intervention.

[Congenital Intermittent Third-degree Atrioventricular Block Associated with Retinoid Exposure in Pregnancy]

BACKGROUND

The retinoid acitretin, which has been approved as an effective therapy for severe keratinization disorders, is highly teratogenic, and exposure in the first trimester of pregnancy is associated with the risk of miscarriage and various malformations, including congenital heart defects. Cardiac conduction system disorders have not been described so far.

CASE REPORT

A 24-year-old woman was treated with acitretin for dyskeratosis follicularis until pregnancy was diagnosed at 12 weeks of gestation. The female infant was born after 35 weeks gestation by cesarean section because of intermittent fetal bradycardia. The baby was vigorous at birth (Apgar 9, 10, 10 at 1, 5 and 10 min) but displayed intermittent third-degree atrioventricular block. A search for maternal autoantibodies and viral infections gave negative findings.

CONCLUSION

The spectrum of disorders caused by intrauterine retinoid exposure appears to include atrioventricular conduction failure.