Potential of dietary polyphenols for protection from age-related decline and neurodegeneration: a role for gut microbiota?

Many epidemiological studies have shown the beneficial effects of a largely plant-based diet, and the strong association between the consumption of a Mediterranean-type diet with healthy aging including a lower risk of cognitive decline. The Mediterranean diet is characterized by a high intake of olive oil, fruits and vegetables and is rich in dietary fiber and polyphenols - both of which have been postulated to act as important mediators of these benefits. Polyphenols are large molecules produced by plants to protect them from environmental threats and injury. When ingested by humans, as little as 5% of these molecules are absorbed in the small intestine with the majority metabolized by the gut microbiota into absorbable simple phenolic compounds. Flavan-3-ols, a type of flavonoid, contained in grapes, berries, pome fruits, tea, and cocoa have been associated with many beneficial effects on several risk factors for cardiovascular disease, cognitive function and brain regions involved in memory formation. Both preclinical and clinical studies suggest that these brain and heart benefits can be attributed to endothelial vascular effects and anti-inflammatory properties among others. More recently the gut microbiota has emerged as a potential modulator of the aging brain and intriguingly polyphenols have been shown to alter microbiota composition and be metabolized by different microbial species. However, there is a need for well controlled studies in large populations to identify predictors of response, particularly given the vast inter-individual variation of human gut microbiota.

Neuroprotection after cardiac arrest with 2-iminobiotin: a single center phase IIa study on safety, tolerability, and pharmacokinetics

Background

Brain injury is a serious problem in patients who survive out-of-hospital cardiac arrest (OHCA). Neuroprotective drugs could reduce hypoxic-ischemic reperfusion injury. The aim of this study was to investigate the safety, tolerability, and pharmacokinetics (PK) of 2-iminobiotin (2-IB), a selective inhibitor of neuronal nitric oxide synthase.

Methods

Single-center, open-label dose-escalation study in adult OHCA patients, investigating three 2-IB dosing schedules (targeting an AUC_0-24h of 600-1,200 ng*h/m in cohort A, of 2,100-3,300 ng*h/mL in cohort B, and 7,200-8,400 of ng*h/mL in cohort C). Safety was investigated by monitoring vital signs until 15 min after study drug administration and adverse events up to 30 days after admission. Blood sampling for PK analysis was performed. Brain biomarkers and patient outcomes were collected 30 days after OHCA.

Results

A total of 21 patients was included, eight in cohort A and B and five in cohort C. No changes in vital signs were observed, and no adverse events related to 2-IB were reported. A two-compartment PK model described data the best. Exposure in group A (dosed on bodyweight) was three times higher than targeted (median AUC_0-24h 2,398 ng*h/mL). Renal function was an important covariate; therefore, in cohort B, dosing was performed on eGFR on admission. In cohort B and C, the targeted exposure was met (median AUC_0-24h 2,917 and 7,323 ng*h/mL, respectively).

Conclusion

The administration of 2-IB to adults after OHCA is feasible and safe. PK can be well predicted with correction for renal function on admission. Efficacy studies with 2-IB after OHCA are needed.

Association between early cumulative fluid balance and successful liberation from invasive ventilation in COVID-19 ARDS patients — insights from the PRoVENT-COVID study: a national, multicenter, observational cohort analysis

Background

Increasing evidence indicates the potential benefits of restricted fluid management in critically ill patients. Evidence lacks on the optimal fluid management strategy for invasively ventilated COVID-19 patients. We hypothesized that the cumulative fluid balance would affect the successful liberation of invasive ventilation in COVID-19 patients with acute respiratory distress syndrome (ARDS).

Methods

We analyzed data from the multicenter observational ‘PRactice of VENTilation in COVID-19 patients’ study. Patients with confirmed COVID-19 and ARDS who required invasive ventilation during the first 3 months of the international outbreak (March 1, 2020, to June 2020) across 22 hospitals in the Netherlands were included. The primary outcome was successful liberation of invasive ventilation, modeled as a function of day 3 cumulative fluid balance using Cox proportional hazards models, using the crude and the adjusted association. Sensitivity analyses without missing data and modeling ARDS severity were performed.

Results

Among 650 patients, three groups were identified. Patients in the higher, intermediate, and lower groups had a median cumulative fluid balance of 1.98 L (1.27–7.72 L), 0.78 L (0.26–1.27 L), and − 0.35 L (− 6.52–0.26 L), respectively. Higher day 3 cumulative fluid balance was significantly associated with a lower probability of successful ventilation liberation (adjusted hazard ratio 0.86, 95% CI 0.77–0.95, P = 0.0047). Sensitivity analyses showed similar results.

Conclusions

In a cohort of invasively ventilated patients with COVID-19 and ARDS, a higher cumulative fluid balance was associated with a longer ventilation duration, indicating that restricted fluid management in these patients may be beneficial.

Trial registration Clinicaltrials.gov (NCT04346342); Date of registration: April 15, 2020.

Graphical abstract

Attitudes towards vaccination are associated with vaccination behaviour among university students

Introduction

Vaccination behaviour is influenced by various determinants. Evidence indicates a higher COVID-19 vaccine hesitancy among university students due to their age and a lower risk of complications compared to the general population in Germany. However, little is known about other COVID-19-related determinants for the population of German university students. This study aimed to investigate determinants of vaccination behaviour among German university students.

Methods

The cross-sectional COVID-19 German Student Well-being Study was conducted at five German universities at the end of 2021 via an online survey (n = 7.267). Multiple logistic regressions were calculated to examine associations of vaccination behaviour (not vaccinated vs. fully vaccinated) and attitudes towards vaccination (5Cs: confidence in the safety of the vaccine, complacency - not perceiving diseases as high risk, constraints - structural and psychological barriers, calculation - engagement in information seeking, collective responsibility - willingness to protect others), health literacy in a pandemic (CHL-P), and additional determinants.

Results

All 5Cs were associated with the vaccination status ‘fully vaccinated’, except for complacency. Regarding CHL-P, we found that students who felt that the current scientific knowledge about COVID-19 in terms of the policy decisions on pandemic measures was very complex had a higher odds for being vaccinated (OR = 3.02; 95% CI: 2.26-4.04). Regarding additional determinants, the analysis revealed that students who had been previously infected had in all regressions a lower odds for being vaccinated compared to students with no previous infection.

Conclusions

Due to the strong association of the attitudes towards vaccination and vaccination behaviour among university students, we recommend that the different components of the 5Cs should be considered in future COVID-19 vaccination campaigns in the university context.

Key messages

Change in the financial situation of students during COVID-19 and its impact on depressive symptoms

Background

Students faced unique challenges during the COVID-19 pandemic that may have affected their financial situation as well as their mental health. This study sought to examine whether changes in financial situation before and during the COVID-19 pandemic were associated with depressive symptoms among German university students.

Methods

The cross-sectional COVID-19 German Student Well-being Study (C19 GSWS; N = 7,267) was implemented at five German universities between 27.10. and 14.11.2021. Students were asked if they had had sufficient financial resources to cover monthly expenses before the pandemic, as well as during the first and third waves of the pandemic. Depressive symptoms were assessed using the CES-D 8 (score ranges 0-24) and the PHQ-2 (0-6); higher scores indicating more severe depressive symptoms. Linear regression models were used to examine associations between variables.

Results

A worsened financial situation between the first and the third wave of the pandemic was associated with a one point (0.95) increase on the CES-D 8 scale (95% CI: 0.61, 1.29) and an improved financial situation with a decrease by 0.81 points (95% CI: -1.20, -0.42). A worsened financial situation was associated with a 0.26-point increase in PHQ-2 (95% CI: 0.14, 0.37) and an improved financial situation with a -0.12-point decrease (95% CI: -0.25, 0.01). Similarly, worsened financial situation in the third wave compared to prior to the pandemic, was also associated with an increase in CES-D 8 score and PHQ-2 and an improved financial situation with a decrease in CES-D 8 and PHQ-2.

Conclusions

Our findings suggest associations between students’ financial situation during the COVID-19 pandemic and their mental health. Due to their instable financial situation, students are a vulnerable group in need of mental and financial support during pandemic crises.

Key messages

Carbon Dioxide, Blood Pressure, and Perioperative Stroke: A Retrospective Case-Control Study

BACKGROUND

The relationship between intraoperative physiology and postoperative stroke is incompletely understood. Preliminary data suggest that either hypo- or hypercapnia coupled with reduced cerebrovascular inflow (e.g., due to hypotension) can lead to ischemia. This study tested the hypothesis that the combination of intraoperative hypotension and either hypo- or hypercarbia is associated with postoperative ischemic stroke.

METHODS

We conducted a retrospective, case-control study via the Multicenter Perioperative Outcomes Group. Noncardiac, nonintracranial, and nonmajor vascular surgical cases (18 yr or older) were extracted from five major academic centers between January 2004 and December 2015. Ischemic stroke cases were identified via manual chart review and matched to controls (1:4). Time and reduction below key mean arterial blood pressure thresholds (less than 55 mmHg, less than 60 mmHg, less than 65 mmHg) and outside of specific end-tidal carbon dioxide thresholds (30 mmHg or less, 35 mmHg or less, 45 mmHg or greater) were calculated based on total area under the curve. The association between stroke and total area under the curve values was then tested while adjusting for relevant confounders.

RESULTS

In total, 1,244,881 cases were analyzed. Among the cases that screened positive for stroke (n = 1,702), 126 were confirmed and successfully matched with 500 corresponding controls. Total area under the curve was significantly associated with stroke for all thresholds tested, with the strongest combination observed with mean arterial pressure less than 55 mmHg (adjusted odds ratio per 10 mmHg-min, 1.17 [95% CI, 1.10 to 1.23], P < 0.0001) and end-tidal carbon dioxide 45 mmHg or greater (adjusted odds ratio per 10 mmHg-min, 1.11 [95% CI, 1.10 to 1.11], P < 0.0001). There was no interaction effect observed between blood pressure and carbon dioxide.

CONCLUSIONS

Intraoperative hypotension and carbon dioxide dysregulation may each independently increase postoperative stroke risk.

EDITOR’S PERSPECTIVE

Heifers don't care: no evidence of negative impact on animal welfare of growing heifers when using virtual fences compared to physical fences for grazing

Virtual fencing (VF) represents a way to simplify traditional pasture management with its high labour and cost requirements for fencing and to make better use of the 'beneficial' agronomic and ecological effects of livestock grazing. In this study, the VF technology (® Nofence, AS, Batnfjordsøra Norway) was used with Fleckvieh heifers to investigate possible welfare impacts on the animals compared to conventionally fenced animals when they were trained to respond correctly to the system. The Nofence® collars (attached to the neck of the heifers) send acoustic signals as a warning when the animals approach the VF line, which was set up by GPS coordinates within the Nofence®-App, followed by an electric pulse when they do not stop or return. The heifers had no experience with VF prior to the study. Two treatments (VF versus physical fencing (PF)) were applied to six groups of four heifers each (three groups per treatment) over three 12-day time replicates. One VF line separated the pasture of the VF group into an accessible or non-accessible area. The control group had a PF line. Both groups were equipped with Nofence® collars (deactivated for the PF group). The trial took place on two adjacent paddocks of 1 000 m² each following a 12-day schedule which was divided into three sections: visual support of the VF line by a physical barrier (first 2 days), only virtual border without visual support, moving the VF line (on day 8). Each time replicate followed the next successively on different paddocks with two new groups of heifers, which were grazed 5 h daily. During the whole experiment, the behaviour of each of the four animals per group was continuously observed; 2 h a.m., 2 h p.m. Exclusion by the VF line was effective in our trial. None of the heifers crossed the virtual boundary, i.e. the time spent in exclusion zone was zero. The heifers received 2.70 ± 2.63 acoustic signals and 0.30 ± 0.36 electric pulses (mean ± SD) per heifer and hour during all time replicates. Main cattle behaviour on pasture was not affected by the fencing system. Live weight gain, herbage consumption and faecal cortisol metabolites also revealed no significant differences. The duration until the heifers restarted grazing after an electric pulse from the Nofence® collar was significantly shorter than after an electric pulse from the physical fence. We can summarise that in our study, cattle well-being on pasture was not negatively affected by VF compared to PF.

ICONIC study—conservative versus conventional oxygenation targets in intensive care patients: study protocol for a randomized clinical trial

Background

Oxygen therapy is a widely used intervention in acutely ill patients in the intensive care unit (ICU). It is established that not only hypoxia, but also prolonged hyperoxia is associated with poor patient-centered outcomes. Nevertheless, a fundamental knowledge gap remains regarding optimal oxygenation for critically ill patients. In this randomized clinical trial, we aim to compare ventilation that uses conservative oxygenation targets with ventilation that uses conventional oxygen targets with respect to mortality in ICU patients.

Methods

The “ConservatIve versus CONventional oxygenation targets in Intensive Care patients” trial (ICONIC) is an investigator-initiated, international, multicenter, randomized clinical two-arm trial in ventilated adult ICU patients. The ICONIC trial will run in multiple ICUs in The Netherlands and Italy to enroll 1512 ventilated patients. ICU patients with an expected mechanical ventilation time of more than 24 h are randomized to a ventilation strategy that uses conservative (PaO₂ 55–80 mmHg (7.3–10.7 kPa)) or conventional (PaO₂ 110–150 mmHg (14.7–20 kPa)) oxygenation targets. The primary endpoint is 28-day mortality. Secondary endpoints are ventilator-free days at day 28, ICU mortality, in-hospital mortality, 90-day mortality, ICU- and hospital length of stay, ischemic events, quality of life, and patient opinion of research and consent in the emergency setting.

Discussion

The ICONIC trial is expected to provide evidence on the effects of conservative versus conventional oxygenation targets in the ICU population. This study may guide targeted oxygen therapy in the future.

Trial registration

Trialregister.nl NTR7376. Registered on 20 July, 2018.

Herpes Simplex Virus Meningoencephalitis Following Pulse-Dose Methylprednisolone: A Case Report and Literature Review

Patient: Male, 76-year-old

Final Diagnosis: Herpes simplex virus type 1 (HSV-1) encephalitis

Symptoms: Encephalopathy

Medication: —

Clinical Procedure: Lumbar puncture

Specialty: Critical Care Medicine

Practice of tracheostomy in patients with acute respiratory failure related to COVID-19 - Insights from the PRoVENT-COVID study

Objective

Invasively ventilated patients with acute respiratory failure related to coronavirus disease 2019 (COVID–19) potentially benefit from tracheostomy. The aim of this study was to determine the practice of tracheostomy during the first wave of the pandemic in 2020 in the Netherlands, to ascertain whether timing of tracheostomy had an association with outcome, and to identify factors that had an association with timing.

Methods

Secondary analysis of the ‘PRactice of VENTilation in COVID–19’ (PRoVENT–COVID) study, a multicenter observational study, conducted from March 1, 2020 through June 1, 2020 in 22 Dutch intensive care units (ICU) in the Netherlands. The primary endpoint was the proportion of patients receiving tracheostomy; secondary endpoints were timing of tracheostomy, duration of ventilation, length of stay in ICU and hospital, mortality, and factors associated with timing.

Results

Of 1023 patients, 189 patients (18.5%) received a tracheostomy at median 21 [17 to 28] days from start of ventilation. Timing was similar before and after online publication of an amendment to the Dutch national guidelines on tracheostomy focusing on COVID–19 patients (21 [17–28] vs. 21 [17–26] days). Tracheostomy performed ≤ 21 days was independently associated with shorter duration of ventilation (median 26 [21 to 32] vs. 40 [34 to 47] days) and higher mortality in ICU (22.1% vs. 10.2%), hospital (26.1% vs. 11.9%) and at day 90 (27.6% vs. 14.6%). There were no patient demographics or ventilation characteristics that had an association with timing of tracheostomy.

Conclusions

Tracheostomy was performed late in COVID–19 patients during the first wave of the pandemic in the Netherlands and timing of tracheostomy possibly had an association with outcome. However, prospective studies are needed to further explore these associations. It remains unknown which factors influenced timing of tracheostomy in COVID–19 patients.

Effectiveness, safety and efficacy of INTELLiVENT-adaptive support ventilation, a closed-loop ventilation mode for use in ICU patients - a systematic review

Introduction: INTELLiVENT-Adaptive Support Ventilation (INTELLiVENT-ASV), an advanced closed-loop ventilation mode for use in intensive care unit (ICU) patients, is equipped with algorithms that automatically adjust settings on the basis of physiologic signals and patient's activity. Here we describe its effectiveness, safety, and efficacy in various types of ICU patients.Areas covered: A systematic search conducted in MEDLINE, EMBASE, the Cochrane Central register of Controlled Trials (CENTRAL), and in Google Scholar identified 10 randomized clinical trials.Expert opinion: Studies suggest INTELLiVENT-ASV to be an effective automated mode with regard to the titrations of tidal volume, airway pressure, and oxygen. INTELLiVENT-ASV is as safe as conventional modes. However, thus far studies have not shown INTELLiVENT-ASV to be superior to conventional modes with regard to duration of ventilation and other patient-centered outcomes. Future studies are needed to test its efficacy.

Postoperative bowel complications after non-shunt-related neurosurgical procedures: case series and review of the literature

Postoperative bowel complications after non-shunt-related neurosurgical procedures are relatively rare. In an effort to identify the primary risk factors, we evaluated postoperative bowel complications in cranial, endovascular, and spinal procedures in neurosurgery patients using our own institutional case series along with a literature review.We identified severe postoperative bowel complications that occurred at our institution after non-shunt-related neurosurgical procedures between July 2016 and December 2018. We also completed a systematic review of PubMed/MEDLINE using search terms related to bowel complications.At our institution, 7 patients (average age 49.7 ± 9.5 years, range 34-60; no apparent sex predilection) had severe postoperative bowel complications after undergoing a total of 10 neurosurgical procedures. Diagnosis was on average 1 week postoperatively (range 5-13 days), and the time between radiographic/clinical diagnosis and either surgery or death was 1.3 ± 1.4 days (range 0-4 days). Bowel perforation occurred in 4 patients. Five of the patients died, 3 as a direct result of the bowel complication. In the literature review, we identified 6487 spine and 66 cranial and/or endovascular bowel complications after neurosurgical procedures.Our case series and literature review demonstrate that severe postoperative bowel complications after non-shunt-related neurosurgical procedures, while rare, carry significant morbidity/mortality despite prompt and aggressive management. These can also happen without direct injury to bowel tissue, instead occurring as sequelae of inflammatory processes, as well as from delayed mobility, extended use of opiate narcotics, and lack of standardized protocols to ensure early bowel movements that likely stems from unfamiliarity with this potentially devastating complication.

Quantitative analysis of EEG reactivity for neurological prognostication after cardiac arrest

OBJECTIVE

To test whether 1) quantitative analysis of EEG reactivity (EEG-R) using machine learning (ML) is superior to visual analysis, and 2) combining quantitative analyses of EEG-R and EEG background pattern increases prognostic value for prediction of poor outcome after cardiac arrest (CA).

METHODS

Several types of ML models were trained with twelve quantitative features derived from EEG-R and EEG background data of 134 adult CA patients. Poor outcome was a Cerebral Performance Category score of 3-5 within 6 months.

RESULTS

The Random Forest (RF) trained on EEG-R showed the highest AUC of 83% (95-CI 80-86) of tested ML classifiers, predicting poor outcome with 46% sensitivity (95%-CI 40-51) and 89% specificity (95%-CI 86-92). Visual analysis of EEG-R had 80% sensitivity and 65% specificity. The RF was also the best classifier for EEG background (AUC 85%, 95%-CI 83-88) at 24 h after CA, with 62% sensitivity (95%-CI 57-67) and 84% specificity (95%-CI 79-88). Combining EEG-R and EEG background RF classifiers reduced the number of false positives.

CONCLUSIONS

Quantitative EEG-R using ML predicts poor outcome with higher specificity, but lower sensitivity compared to visual analysis of EEG-R, and is of some additional value to ML on EEG background data.

SIGNIFICANCE

Quantitative EEG-R using ML is a promising alternative to visual analysis and of some added value to ML on EEG background data.

Visual and Patient-Reported Outcomes of a Diffractive Trifocal Intraocular Lens Compared with Those of a Monofocal Intraocular Lens

PURPOSE

To evaluate the effectiveness and safety of a trifocal intraocular lens (IOL), the TFNT00 (Alcon, Fort Worth, TX), versus a monofocal IOL, the SN60AT (Alcon).

DESIGN

Food and Drug Administration-approved, prospective, multicenter, nonrandomized, parallel-group, assessor-masked, confirmatory trial.

PARTICIPANTS

Patients enrolled were 22 years of age or older with a diagnosis of bilateral cataract with planned removal by phacoemulsification with a clear corneal incision.

METHODS

Consented participants selected their preferred IOL, which was implanted sequentially into each eye of patients meeting eligibility criteria.

MAIN OUTCOME MEASURES

The coprimary effectiveness outcomes were mean photopic monocular best-corrected distance visual acuity (BCDVA; 4 m) and distance-corrected near visual acuity (DCNVA; 40 cm) at 6 months after surgery. Secondary effectiveness outcomes included mean monocular distance-corrected intermediate visual acuity (DCIVA; 66 cm) and proportion of participants responding "never" to question 1 of the Intraocular Lens Satisfaction questionnaire (regarding frequency of spectacle use in the past 7 days). Safety outcomes included frequency of "severe" and "most bothersome" visual disturbances.

RESULTS

Two hundred forty-three patients underwent cataract surgery with bilateral implantation of the TFNT00 (n = 129) or SN60AT (n = 114) and were followed up for 6 months. Noninferiority of TFNT00 to SN60AT in mean photopic monocular BCDVA (95% upper confidence limit of the difference was <0.1 logarithm of the minimum angle of resolution [logMAR] margin), and superiority in mean photopic monocular DCNVA (difference of 0.42 logMAR; P < 0.001) and DCIVA (difference of 0.26 logMAR; P < 0.001) were demonstrated. The proportion of patients never requiring glasses overall was superior for TFNT00 versus SN60AT (80.5% and 8.2%, respectively). Starbursts, halos, and glare were the most frequently rated severe symptoms with TFNT00; however, less than 5% of patients were very bothered at month 6.

CONCLUSIONS

The TFNT00 exhibited superior monocular DCNVA and DCIVA to a spherical monofocal IOL, with comparable monocular BCDVA. Binocular visual acuity was 20/25 or better for distance to near (+0.5 D to -2.5 D), resulting in high levels of spectacle independence. Less than 5% of patients were very bothered by the photic visual disturbances associated with the TFNT00 at 6 months after surgery.

A reference high-pressure CH4 adsorption isotherm for zeolite Y: results of an interlaboratory study

This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess methane adsorption isotherms on NIST Reference Material RM 8850 (Zeolite Y), at 25 °C up to 7.5 MPa. Twenty laboratories participated in the study and contributed over one-hundred adsorption isotherms of methane on Zeolite Y. From these data, an empirical reference equation was determined, along with a 95% uncertainty interval (Uk=2). By requiring participants to replicate a high-pressure reference isotherm for carbon dioxide adsorption on NIST Reference Material RM 8852 (ZSM-5), this interlaboratory study also demonstrated the usefulness of reference isotherms in evaluating the performance of high-pressure adsorption experiments.

A variational formulation for steady surface water waves on a Beltrami flow

This paper considers steady surface waves ‘riding’ a Beltrami flow (a three-dimensional flow with parallel velocity and vorticity fields). It is demonstrated that the hydrodynamic problem can be formulated as two equations for two scalar functions of the horizontal spatial coordinates, namely the elevation η of the free surface and the potential Φ defining the gradient part (in the sense of the Hodge–Weyl decomposition) of the horizontal component of the tangential fluid velocity there. These equations are written in terms of a non-local operator H ( η ) mapping Φ to the normal fluid velocity at the free surface, and are shown to arise from a variational principle. In the irrotational limit, the equations reduce to the Zakharov–Craig–Sulem formulation of the classical three-dimensional steady water-wave problem, while H ( η ) reduces to the familiar Dirichlet–Neumann operator.

Early or late pregnancy loss and development of clinical cardiovascular disease risk factors: a prospective cohort study

OBJECTIVE

To assess the association between the outcome of a woman's first pregnancy and risk of clinical cardiovascular disease risk factors.

DESIGN

Prospective cohort study.

SETTING AND POPULATION

Nurses' Health Study II.

METHODS

Multivariable-adjusted Cox proportional hazards models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between first pregnancy outcome and hypertension, type 2 diabetes, and hypercholesterolemia.

MAIN OUTCOME MEASURES

Hypertension, type 2 diabetes, and hypercholesterolemia.

RESULTS

Compared to women who reported a singleton live first birth, women with early spontaneous abortion (<12 weeks) had a greater rate of type 2 diabetes (HR: 1.20; 95% CI: 1.07-1.34) and hypercholesterolemia (HR: 1.06; 95% CI: 1.02-1.10), and a marginally increased rate of hypertension (HR: 1.05, 95% CI: 1.00-1.11). Late spontaneous abortion (12-19 weeks) was associated with an increased rate of type 2 diabetes (HR: 1.38; 95% CI: 1.14-1.65), hypercholesterolemia (HR: 1.11; 95% CI: 1.03-1.19), and hypertension (HR: 1.15; 95% CI: 1.05-1.25). The rates of type 2 diabetes (HR: 1.45; 95% CI: 1.13-1.87) and hypertension (HR: 1.15; 95% CI: 1.01-1.30) were higher in women who delivered stillbirth. In contrast, women whose first pregnancy ended in an induced abortion had lower rates of hypertension (HR: 0.87; 95% CI: 0.84-0.91) and type 2 diabetes (HR: 0.89; 95% CI: 0.79-0.99) than women with a singleton live birth.

CONCLUSIONS

Several types of pregnancy loss were associated with an increased rate of hypertension, type 2 diabetes, and hypercholesterolemia, which may provide novel insight into the pathways through which pregnancy outcomes and CVD are linked.

TWEETABLE ABSTRACT

Pregnancy loss is associated with later maternal risk of hypertension, type 2 diabetes, and hypercholesterolemia.

Small-amplitude static periodic patterns at a fluid–ferrofluid interface

We establish the existence of static doubly periodic patterns (in particular rolls, squares and hexagons) on the free surface of a ferrofluid near onset of the Rosensweig instability, assuming a general (nonlinear) magnetization law. A novel formulation of the ferrohydrostatic equations in terms of Dirichlet–Neumann operators for nonlinear elliptic boundary-value problems is presented. We demonstrate the analyticity of these operators in suitable function spaces and solve the ferrohydrostatic problem using an analytic version of Crandall–Rabinowitz local bifurcation theory. Criteria are derived for the bifurcations to be sub-, super- or transcritical with respect to a dimensionless physical parameter.

Genomic insights into natural selection in the common loon (Gavia immer): evidence for aquatic adaptation

Background

The common loon (Gavia immer) is one of five species that comprise the avian order Gaviiformes. Loons are specialized divers, reaching depths up to 60 m while staying submerged for intervals up to three minutes. In this study we used comparative genomics to investigate the genetic basis of the common loon adaptations to its ecological niche. We used Illumina short read DNA sequence data from a female bird to produce a draft assembly of the common loon (Gavia immer) genome.

Results

We identified 14,169 common loon genes, which based on well-resolved avian genomes, represent approximately 80.7% of common loon genes. Evolutionary analyses between common loon and Adelie penguin (Pygoscelis adeliae), red-throated loon (Gavia stellata), chicken (Gallus gallus), northern fulmar (Fulmarus glacialis), and rock pigeon (Columba livia) show 164 positively selected genes in common and red-throated loons. These genes were enriched for a number of protein classes, including those involved in muscle tissue development, immunoglobulin function, hemoglobin iron binding, G-protein coupled receptors, and ATP metabolism.

Conclusions

Signatures of positive selection in these areas suggest the genus Gavia may have adapted for underwater diving by modulating their oxidative and metabolic pathways. While more research is required, these adaptations likely result in (1) compensations in oxygen respiration and energetic metabolism, (2) low-light visual acuity, and (3) elevated solute exchange. This work represents the first effort to understand the genomic adaptations of the common loon as well as other Gavia and may have implications for subsequent studies that target particular genes for loon population genetic, ecological or conservation studies.

Electronic supplementary material

The online version of this article (10.1186/s12862-018-1181-6) contains supplementary material, which is available to authorized users.

Intracranial Epidural Metastases of Adrenal Pheochromocytoma: A Rare Entity

BACKGROUND

Pheochromocytomas are uncommon neuroendocrine tumors of the adrenal medulla. Malignant behavior is seen in approximately 10% of these lesions, evidenced by distant metastasis to sites without chromaffin tissue. Here we report a rare case of intracranial epidural metastases of an adrenal pheochromocytoma in a 24-year-old man.

CASE DESCRIPTION

The patient originally presented at age 10 years with adrenal pheochromocytoma and subsequently developed extensive metastatic bone and lung disease. He was monitored in the intervening years until recent imaging demonstrated an enlarging right parietal mass. On surgical resection of the parietal lesion, the tumor was highly vascularized and confined to the epidural space.

CONCLUSIONS

To the best of our knowledge, this is the first reported case of metastatic epidural spread of pheochromocytoma without concomitant subdural or intraparenchymal extension.

Punch biopsies shorten time to clearance of high-risk human papillomavirus infections of the uterine cervix

Background

The primary objective was to determine human papilloma virus (HPV) clearance rate after cervical biopsy among women with persistent high-risk HPV infection compared with spontaneous HPV clearance rate in the absence of biopsy.

Methods

We collected data from a dedicated screening program of women aged 30–70 years old. Inclusion criteria for the baseline non-interventional cohort were a positive HPV test (hybrid capture 2, HC2) and normal cytology. In the baseline cohort women were followed with approximately yearly HPV-tests and cytology until HPV regressed (one negative HPV test) or interventions in the form of diagnostic biopsies or therapy. Women who had a diagnostic biopsy were included in the biopsy cohort and followed until HPV regression or therapy. Observed HPV regression rates and time to HPV regression were compared between baseline and biopsy cohorts. For the comparison, we used Fisher’s exact test for the HPV regression rates and interval-censored, accelerated failure time model for time to HPV regression.

Results

Among the 1079 women included in the baseline cohort, 499 (46.3%) had HPV clearance and 475 were referred for colposcopy with biopsy. The biopsy cohort comprised all women who were not treated and had at least one HC2 test after biopsy (201/475; 42.3%). Of those, 138 (68.7%) experienced HPV regression. In the biopsy cohort, time to clearance of HPV infection was approximately halved (0.46, 95% CI 0.38–0.56) compared with the baseline cohort. This result was robust in a wide range of sensitivity analyses.

Conclusions

A higher proportion of women cleared their HPV infection, and time to HPV clearance was shorter in the biopsy cohort than in the baseline cohort. It is reassuring for clinicians to know that conservative management of patients with HPV persistency is successful when colposcopy with biopsies excludes high-grade disease.

Identification and validation of distinct biological phenotypes in patients with acute respiratory distress syndrome by cluster analysis

RATIONALE

We hypothesised that patients with acute respiratory distress syndrome (ARDS) can be clustered based on concentrations of plasma biomarkers and that the thereby identified biological phenotypes are associated with mortality.

METHODS

Consecutive patients with ARDS were included in this prospective observational cohort study. Cluster analysis of 20 biomarkers of inflammation, coagulation and endothelial activation provided the phenotypes in a training cohort, not taking any outcome data into account. Logistic regression with backward selection was used to select the most predictive biomarkers, and these predicted phenotypes were validated in a separate cohort. Multivariable logistic regression was used to quantify the independent association with mortality.

RESULTS

Two phenotypes were identified in 454 patients, which we named 'uninflamed' (N=218) and 'reactive' (N=236). A selection of four biomarkers (interleukin-6, interferon gamma, angiopoietin 1/2 and plasminogen activator inhibitor-1) could be used to accurately predict the phenotype in the training cohort (area under the receiver operating characteristics curve: 0.98, 95% CI 0.97 to 0.99). Mortality rates were 15.6% and 36.4% (p<0.001) in the training cohort and 13.6% and 37.5% (p<0.001) in the validation cohort (N=207). The 'reactive phenotype' was independent from confounders associated with intensive care unit mortality (training cohort: OR 1.13, 95% CI 1.04 to 1.23; validation cohort: OR 1.18, 95% CI 1.06 to 1.31).

CONCLUSIONS

Patients with ARDS can be clustered into two biological phenotypes, with different mortality rates. Four biomarkers can be used to predict the phenotype with high accuracy. The phenotypes were very similar to those found in cohorts derived from randomised controlled trials, and these results may improve patient selection for future clinical trials targeting host response in patients with ARDS.

Preoperative weight loss program targeting women with overweight and hypertrophy of the breast - a pilot study

Among women with hypertrophic breasts, the clear majority are overweight or obese. Owing to increased risk of complications, women with a body mass index (BMI) above 25 kg m ^-2 are precluded from reduction mammaplasty. The primary aim was to investigate if intensive weight loss could ready women with overweight for breast reduction surgery. Six women, all overweight [BMI 30.9 {28.5; 35.8} kg m ^-2 ] with symptomatic hypertrophy of the breast, were included a 12-week weight loss program. All women desired reduction mammaplasty and were motivated for preoperational weight loss. The first 8 weeks consisted of a formula-based diet supplying 800 kcal daily, in the subsequent 4 weeks regular foods were reintroduced increasing the intake to 1200 kcal daily. Five women completed the trial, and achieved a median (range) weight loss of 10.2 (6.5; 19) kg. Initial breast volume was 1100-2500 mL per breast, this was reduced by 300 (200; 500) mL after the intervention; equivalent to approximately 19%. Waist, hip, upper arm and thorax circumference were significantly reduced following weight loss. At end of study, all the women still suffered from symptomatic breast hypertrophy to substantiate reduction mammaplasty. Surgeries were performed 2 months thereafter. A 12-week intensive preoperative weight loss program enabled women with obesity for breast reduction surgery. Breast size was reduced proportionally more than total weight loss among women with hypertrophy.

Intensive care unit-acquired weakness

When critically ill, a severe weakness of the limbs and respiratory muscles often develops with a prolonged stay in the intensive care unit (ICU), a condition vaguely termed intensive care unit-acquired weakness (ICUAW). Many of these patients have serious nerve and muscle injury. This syndrome is most often seen in surviving critically ill patients with sepsis or extensive inflammatory response which results in increased duration of mechanical ventilation and hospital length of stay. Patients with ICUAW often do not fully recover and the disability will seriously impact on their quality of life. In this chapter we discuss the current knowledge on the pathophysiology and risk factors of ICUAW. Tools to diagnose ICUAW, how to separate ICUAW from other disorders, and which possible treatment strategies can be employed are also described. ICUAW is finally receiving the attention it deserves and the expectation is that it can be better understood and prevented.

Electroencephalographic reactivity testing in unconscious patients: a systematic review of methods and definitions

Electroencephalographic (EEG) reactivity testing is often presented as a clear-cut element of electrophysiological testing. Absence of EEG reactivity is generally considered an indicator of poor outcome, especially in patients after cardiac arrest. However, guidelines do not clearly describe how to test for reactivity and how to evaluate the results. In a quest for clear guidelines, we performed a systematic review aimed at identifying testing methods and definitions of EEG reactivity. We systematically searched the literature between 1970 and May 2016. Methodological quality of the studies was assessed using the QUality In Prognostic Studies tool. Quality of the descriptions of stimulus protocol and reactivity definition was rated on a four-category grading scale based on reproducibility. We found that protocols for EEG reactivity testing vary greatly and descriptions of protocols are almost never replicable. Furthermore, replicable definitions of presence or absence of EEG reactivity are never provided. In order to draw firm conclusions on EEG reactivity as a prognostic factor, future studies should include a precise stimulation protocol and reactivity definition to facilitate guideline formation.

BEESCOUT: A model of bee scouting behaviour and a software tool for characterizing nectar/pollen landscapes for BEEHAVE

•

BEESCOUT is a spatially explicit, individual-based model of scouting bees.

•

It determines the detection probabilities of food sources.

•

It can be linked to the honey bee model BEEHAVE to predict colony development.

Social bees are central place foragers collecting floral resources from the surrounding landscape, but little is known about the probability of a scouting bee finding a particular flower patch. We therefore developed a software tool, BEESCOUT, to theoretically examine how bees might explore a landscape and distribute their scouting activities over time and space. An image file can be imported, which is interpreted by the model as a “forage map” with certain colours representing certain crops or habitat types as specified by the user. BEESCOUT calculates the size and location of these potential food sources in that landscape relative to a bee colony. An individual-based model then determines the detection probabilities of the food patches by bees, based on parameter values gathered from the flight patterns of radar-tracked honeybees and bumblebees. Various “search modes” describe hypothetical search strategies for the long-range exploration of scouting bees. The resulting detection probabilities of forage patches can be used as input for the recently developed honeybee model BEEHAVE, to explore realistic scenarios of colony growth and death in response to different stressors. In example simulations, we find that detection probabilities for food sources close to the colony fit empirical data reasonably well. However, for food sources further away no empirical data are available to validate model output. The simulated detection probabilities depend largely on the bees’ search mode, and whether they exchange information about food source locations. Nevertheless, we show that landscape structure and connectivity of food sources can have a strong impact on the results. We believe that BEESCOUT is a valuable tool to better understand how landscape configurations and searching behaviour of bees affect detection probabilities of food sources. It can also guide the collection of relevant data and the design of experiments to close knowledge gaps, and provides a useful extension to the BEEHAVE honeybee model, enabling future users to explore how landscape structure and food availability affect the foraging decisions and patch visitation rates of the bees and, in consequence, to predict colony development and survival.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].