A giant exoplanet orbiting a very-low-mass star challenges planet formation models

Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought.

Online oxygen monitoring using integrated inkjet-printed sensors in a liver-on-a-chip system

The demand for real-time monitoring of cell functions and cell conditions has dramatically increased with the emergence of organ-on-a-chip (OOC) systems. However, the incorporation of co-cultures and microfluidic channels in OOC systems increases their biological complexity and therefore makes the analysis and monitoring of analytical parameters inside the device more difficult. In this work, we present an approach to integrate multiple sensors in an extremely thin, porous and delicate membrane inside a liver-on-a-chip device. Specifically, three electrochemical dissolved oxygen (DO) sensors were inkjet-printed along the microfluidic channel allowing local online monitoring of oxygen concentrations. This approach demonstrates the existence of an oxygen gradient up to 17.5% for rat hepatocytes and 32.5% for human hepatocytes along the bottom channel. Such gradients are considered crucial for the appearance of zonation of the liver. Inkjet printing (IJP) was the selected technology as it allows drop on demand material deposition compatible with delicate substrates, as used in this study, which cannot withstand temperatures higher than 130 °C. For the deposition of uniform gold and silver conductive inks on the porous membrane, a primer layer using SU-8 dielectric material was used to seal the porosity of the membrane at defined areas, with the aim of building a uniform sensor device. As a proof-of-concept, experiments with cell cultures of primary human and rat hepatocytes were performed, and oxygen consumption rate was stimulated with carbonyl-cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP), accelerating the basal respiration of 0.23 ± 0.07 nmol s-1/106 cells up to 5.95 ± 0.67 nmol s-1/106 cells s for rat cells and the basal respiration of 0.17 ± 0.10 nmol s-1/106 cells by up to 10.62 ± 1.15 nmol s-1/106 cells for human cells, with higher oxygen consumption of the cells seeded at the outflow zone. These results demonstrate that the approach of printing sensors inside an OOC has tremendous potential because IJP is a feasible technique for the integration of different sensors for evaluating metabolic activity of cells, and overcomes one of the major challenges still remaining on how to tap the full potential of OOC systems.

Yield of atrial fibrillation detection with Textile Wearable Holter from the acute phase of stroke: Pilot study of Crypto-AF registry

BACKGROUND

We describe the feasibility of monitoring with a Textile Wearable Holter (TWH) in patients included in Crypto AF registry.

METHODS

We monitored cryptogenic stroke patients from stroke onset (<3days) continuously during 28days. We employed a TWH composed by a garment and a recorder. We compared two garments (Lead and Vest) to assess rate of undiagnosed Atrial Fibrillation (AF) detection, monitoring compliance, comfortability (1 to 5 points), skin lesions, and time analyzed. We describe the timing of AF detection in three periods (0-3, 4-15 and 16-28days).

RESULTS

The rate of undiagnosed AF detection with TWH was 21.9% (32 out of 146 patients who completed the monitoring). Global time compliance was 90% of the time expected (583/644h). The level of comfortability was 4 points (IQR 3-5). We detected reversible skin lesions in 5.47% (8/146). The comfortability was similar but time compliance (in hours) was longer in Vest group 591 (IQR [521-639]) vs. Lead 566 (IQR [397-620]) (p=0.025). Also, time analyzed was more prolonged in Vest group 497 (IQR [419-557]) vs. Lead (336h (IQR [140-520]) (p=0.001)). The incidence of AF increases from 5.6% (at 3days) to 17.5% (at 15th day) and up to 20.9% (at 28th day). The percentage of AF episodes detected only in each period was 12.5% (0-3days); 21.7% (4-15days) and 19% (16-28days).

CONCLUSIONS

28days Holter monitoring from the acute phase of the stroke was feasible with TWH. Following our protocol, only five patients were needed to screen to detected one case of AF.

The effects of prebiotics on microbial dysbiosis, butyrate production and immunity in HIV-infected subjects

Altered interactions between the gut mucosa and bacteria during HIV infection seem to contribute to chronic immune dysfunction. A deeper understanding of how nutritional interventions could ameliorate gut dysbiosis is needed. Forty-four subjects, including 12 HIV⁺ viremic untreated (VU) patients, 23 antiretroviral therapy-treated (ART⁺) virally suppressed patients (15 immunological responders and 8 non-responders) and 9 HIV^- controls (HIV^-), were blindly randomized to receive either prebiotics (scGOS/lcFOS/glutamine) or placebo (34/10) over 6 weeks in this pilot study. We assessed fecal microbiota composition using deep 16S rRNA gene sequencing and several immunological and genetic markers involved in HIV immunopathogenesis. The short dietary supplementation attenuated HIV-associated dysbiosis, which was most apparent in VU individuals but less so in ART⁺ subjects, whose gut microbiota was found more resilient. This compositional shift was not observed in the placebo arm. Significantly, declines in indirect markers of bacterial translocation and T-cell activation, improvement of thymic output, and changes in butyrate production were observed. Increases in the abundance of Faecalibacterium and Lachnospira strongly correlated with moderate but significant increases of butyrate production and amelioration of the inflammatory biomarkers soluble CD14 and high-sensitivity C-reactive protein, especially among VU. Hence, the bacterial butyrate synthesis pathway holds promise as a viable target for interventions.

Benefit of dual-chamber pacing with Closed Loop Stimulation in tilt-induced cardio-inhibitory reflex syncope (BIOSync trial): study protocol for a randomized controlled trial

Background

The efficacy of dual-chamber cardiac pacing in neuro-mediated reflex syncope with a cardio-inhibitory response to the Tilt-Table test (TT) has not been definitively assessed so far. The lack of reproducibility of results from previous studies may be partially explained by discrepancies in subject selection and some weaknesses in design and methods. The European Society of Cardiology (ESC) has set a class IIb indication to pacemaker implantation in this population recommending further research.

Methods/design

The BIOSync study is a multicenter, patient- and outcome-assessor-blind, randomized, parallel-arm, placebo-controlled trial with the objective of assessing the clinical benefit of cardiac pacing in patients with frequently recurrent reflex syncope, suspected (but not proven) to be triggered by asystolic pauses as showing a VASIS 2B response to the TT (>3-s pause regardless of blood pressure drop). The primary and secondary endpoints are time to first post-implantation recurrence of syncope or the combination of pre-syncope or syncope, respectively. One hundred and twenty-eight consenting patients will be 1:1 randomized to dual-chamber cardiac pacing ‘on’ or ‘off’ after pacemaker implantation, and followed up until the first adjudicated primary endpoint event for a maximum of 2 years. The so-called Closed Loop Stimulation function on top of dual-chamber pacing is the pacing mode selected in the study active arm. Participating patients are asked to self-report syncopal symptoms at least every 3 months with self-administered questionnaires addressed to an independent Adjudication Committee. Patients and members of the Adjudicating Committee are blinded to randomization. The study is designed to detect a 40% relative reduction in the 2-year incidence of syncopal recurrences with 80% statistical power.

Discussion

The BIOSync study is designed to definitively assess the benefit of pacing against placebo in reflex syncope patients with a cardio-inhibitory response to the TT. The study will also provide important information on the efficiency of the TT in appropriately selecting reflex syncope patients for cardiac pacing.

Trial registration

ClinicalTrials.gov, identifier: NCT02324920 (27 October 2016, date last accessed).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1941-4) contains supplementary material, which is available to authorized users.

Cardiac Resynchronization is Associated with Reduction in the Rate of ICD Therapies, While Improves Ventricular Function

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External prolonged electrocardiogram monitoring in unexplained syncope and palpitations: results of the SYNARR-Flash study

AIMS

SYNARR-Flash study (Monitoring of SYNcopes and/or sustained palpitations of suspected ARRhythmic origin) is an international, multicentre, observational, prospective trial designed to evaluate the role of external 4-week electrocardiogram (ECG) monitoring in clinical work-up of unexplained syncope and/or sustained palpitations of suspected arrhythmic origin.

METHODS AND RESULTS

Consecutive patients were enrolled within 1 month after unexplained syncope or palpitations (index event) after being discharged from emergency room or hospitalization without a conclusive diagnosis. A 4-week ECG monitoring was obtained by external high-capacity loop recorder (SpiderFlash-T(®), Sorin) storing patient-activated and auto-triggered tracings. Diagnostic monitorings included (i) conclusive events with reoccurrence of syncope or palpitation with concomitant ECG recording (with/without arrhythmias) and (ii) events with asymptomatic predefined significant arrhythmias (sustained supraventricular or ventricular tachycardia, advanced atrio-ventricular block, sinus bradycardia <30 b.p.m., pauses >6 s). SYNARR-Flash study enrolled 395 patients (57.7% females, 56.9 ± 18.7 years, 28.1% with syncope, and 71.9% with palpitations) from 10 European centres. For syncope, the 4-week diagnostic yield was 24.5%, and predictors of diagnostic events were early start of recording (0-15 vs. >15 days after index event) (OR 6.2, 95% CI 1.3-29.6, P = 0.021) and previous history of supraventricular arrhythmias (OR 3.6, 95% CI 1.4-9.7, P = 0.018). For palpitations, the 4-week diagnostic yield was 71.6% and predictors of diagnostic events were history of recurrent palpitations (P < 0.001) and early start of recording (P = 0.001).

CONCLUSION

The 4-week external ECG monitoring can be considered as first-line tool in the diagnostic work-up of syncope and palpitation. Early recorder use, history of supraventricular arrhythmia, and frequent previous events increased the likelihood of diagnostic events during the 4-week external ECG monitoring.

Altered metabolism of gut microbiota contributes to chronic immune activation in HIV-infected individuals

Altered interplay between gut mucosa and microbiota during treated HIV infection may possibly contribute to increased bacterial translocation and chronic immune activation, both of which are predictors of morbidity and mortality. Although a dysbiotic gut microbiota has recently been reported in HIV+ individuals, the metagenome gene pool associated with HIV infection remains unknown. The aim of this study is to characterize the functional gene content of gut microbiota in HIV+ patients and to define the metabolic pathways of this bacterial community, which is potentially associated with immune dysfunction. We determined systemic markers of innate and adaptive immunity in a cohort of HIV-infected individuals on successful antiretroviral therapy without comorbidities and in healthy non-HIV-infected subjects. Metagenome sequencing revealed an altered functional profile, with enrichment of the genes involved in various pathogenic processes, lipopolysaccharide biosynthesis, bacterial translocation, and other inflammatory pathways. In contrast, we observed depletion of genes involved in amino acid metabolism and energy processes. Bayesian networks showed significant interactions between the bacterial community, their altered metabolic pathways, and systemic markers of immune dysfunction. This study reveals altered metabolic activity of microbiota and provides novel insight into the potential host-microbiota interactions driving the sustained inflammatory state in successfully treated HIV-infected patients.

Therapy for Syncope

The diagnostic process in patients with syncope is not always easy and includes a detailed clinical history, physical examination and baseline electrocardiogram; according to the results of these initial approaches, some additional tests must be performed. Using this strategy, the cause of syncope is diagnosed in 60% to 80% of patients; in the remaining patients, risk stratification can be established to identify those patients at risk of having cardiac events or death at midterm follow-up. This article reviews the treatment of patients with syncope according to the different causes.

Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old

INTRODUCTION

In Argentina respiratory disease is the third leading cause of death in children under 5 years. In 2011 influenza vaccination was included in the National Calendar for children between 6 and 24 months (two doses schedule). Influenza vaccine coverage for second dose was 46.1% in 2013. The aim was to determine the proportion of delayed schedules and missed opportunities, to assess the characteristics of missed opportunities for vaccination and to explore the perception of influenza disease and vaccination from the parents of children between 6 and 24 months in different regions of Argentina in 2013.

METHODS

Analytical observational multicenter cross-sectional study. Structured surveys were carried out to the children's parents who were between 6 and 24 months of age during the influenza virus vaccination season (April-October 2013). Chi-Square test was used to assess association and differences between proportions and categorical variables. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. Missed opportunities for vaccination were characterized through the estimation of proportions.

RESULTS

1350 surveys were conducted in the three centers. We detected 65% (884/1340) of delayed influenza vaccination schedules, 97% of them associated with missed opportunities of vaccination. The independent protective factors associated with a decreases risk of delayed schedules were: (a) perception of the importance of influenza vaccination (OR=0.42(0.18-0.94); p=0.035), (b) having less than one year of age (OR=0.75(0.59-0.96); p=0.022), (c) to have received information in pediatric visits or in any media (OR=0.71(0.56-0.90); p=0.004). There was 38% of MOIV in 1st dose and 63.4% in 2nd dose. The main cause of MOIV in 1st dose was not detecting the need for vaccination (39%) and in 2nd dose the unknowledge of the vaccination schedule (35.3%). No cultural reasons were detected.

CONCLUSIONS

High frequency of delayed vaccination schedules and missed opportunities were detected. Parents had little concern about the safety of influenza vaccine.

Simultaneous monitoring of Staphylococcus aureus growth in a multi-parametric microfluidic platform using microscopy and impedance spectroscopy

We describe the design, construction, and characterization of a scalable microfluidic platform that allows continuous monitoring of biofilm proliferation under shear stress conditions. Compared to other previous end-point assay studies, our platform offers the advantages of integration into multiple environments allowing simultaneous optical microscopy and impedance spectroscopy measurements. In this work we report a multi-parametric sensor that can monitor the growth and activity of a biofilm. This was possible by combining two interdigitated microelectrodes (IDuEs), and punctual electrodes to measure dissolved oxygen, K+, Na+ and pH. The IDuE has been optimized to permit sensitive and reliable impedance monitoring of Staphylococcus aureus V329 growth with two- and four-electrode measurements. We distinguished structural and morphological changes on intact cellular specimens using four-electrode data modeling. We also detected antibiotic mediated effects using impedance. Results were confirmed by scanning electrode microscopy and fluorescence microscopy after live/dead cell staining. The bacitracin mediated effects detected with impedance prove that the approach described can be used for guiding the development of novel anti-biofilm agents to better address bacterial infection.