Molecular autopsy for fetal structural anomaly: diagnostic and clinical utility of multidisciplinary team approach

OBJECTIVES

In the West Midlands Regional Genetic Service, cases of perinatal death with a possible genetic diagnosis are evaluated by the Perinatal Pathology Genetic Multidisciplinary Team (MDT). The MDT assessed autopsy findings and considered genomic assessments. The objective of this retrospective service evaluation was to determine the clinical utility of the MDT. This is the first evaluation since the introduction of whole genome and whole exome sequencing in routine clinical care.

METHOD

The outcomes for all the perinatal MDT cases from January 2021 to December 2021 were examined. All cases received a full or partial post-mortem examination (PM) and a chromosomal microarray. Demographics, phenotype, MDT recommendations, genetic testing, diagnoses, outcomes, impact of PM and impact of genetic testing were collected from patient case notes.

RESULTS

One hundred and twenty-three cases were discussed at the MDT meeting in 2021. Genetic evaluation was recommended in 84 cases and accepted in 64 cases. A range of genetic tests were requested according to indication and availability. Thirty diagnoses were identified in 29 cases from 26 unrelated families. The diagnostic yield was 24% (29/123) of all cases or 45% (29/64) of the cases with a suspected genetic diagnosis who underwent genetic testing. PM examination added clinically actionable phenotype data in 79% of cases. A genetic diagnosis enabled accurate counselling of recurrence risk and provision of appropriate follow-up, including prenatal testing and preimplantation diagnosis for patients with inherited conditions.

CONCLUSIONS

Genomic testing was a clinically useful addition to (but not a substitute for) PM examination in perinatal cases associated with structural anomalies. The MDT model helped assess cases and plan appropriate follow-up. Expedited whole genome sequencing or panel-agnostic analysis were most appropriate for heterogeneous presentations. This broad approach can also expand prenatal phenotypes and detect novel disease genes and should be a priority for future research. This article is protected by copyright. All rights reserved.

The QseB response regulator imparts tolerance to positively charged antibiotics by controlling metabolism and minor changes to LPS

The modification of lipopolysaccharide (LPS) in Escherichia coli and Salmonella spp. is primarily controlled by the two-component system PmrAB. LPS modification allows bacteria to avoid killing by positively charged antibiotics like polymyxin B (PMB). We previously demonstrated that in uropathogenic E. coli (UPEC), the sensor histidine kinase PmrB also activates a non-cognate transcription factor, QseB, and this activation somehow augments PMB tolerance in UPEC. Here, we demonstrate-for the first time-that in the absence of the canonical LPS transcriptional regulator, PmrA, QseB can direct some modifications on the LPS. In agreement with this observation, transcriptional profiling analyses demonstrate regulatory overlaps between PmrA and QseB in terms of regulating LPS modification genes. However, both PmrA and QseB must be present for UPEC to mount robust tolerance to PMB. Transcriptional and metabolomic analyses also reveal that QseB transcriptionally regulates the metabolism of glutamate and 2-oxoglutarate, which are consumed and produced during the modification of lipid A. We show that deletion of qseB alters glutamate levels in the bacterial cells. The qseB deletion mutant, which is susceptible to positively charged antibiotics, is rescued by exogenous addition of 2-oxoglutarate. These findings uncover a previously unknown mechanism of metabolic control of antibiotic tolerance that may be contributing to antibiotic treatment failure in the clinic. IMPORTANCE Although antibiotic prescriptions are guided by well-established susceptibility testing methods, antibiotic treatments oftentimes fail. The presented work is significant because it uncovers a mechanism by which bacteria transiently avoid killing by antibiotics. This mechanism involves two closely related transcription factors, PmrA and QseB, which are conserved across Enterobacterales. We demonstrate that PmrA and QseB share regulatory targets in lipid A modification pathway and prove that QseB can orchestrate modifications of lipid A in Escherichia coli in the absence of PmrA. Finally, we show that QseB controls glutamate metabolism during the antibiotic response. These results suggest that rewiring of QseB-mediated metabolic genes could lead to stable antibiotic resistance in subpopulations within the host, thereby contributing to antibiotic treatment failure.

The QseB response regulator imparts tolerance to positively charged antibiotics by controlling metabolism and minor changes to LPS

The modification of lipopolysaccharide (LPS) in Escherichia coli and Salmonella spp . is primarily controlled by the two-component system PmrAB. LPS modification allows bacteria to avoid killing by positively charged antibiotics like polymyxin B. We previously demonstrated that in uropathogenic E. coli (UPEC), the sensor histidine kinase PmrB also activates a non-cognate transcription factor, QseB, and this activation somehow augments polymyxin B tolerance in UPEC. Here, we demonstrate - for the first time - that in the absence of the canonical LPS transcriptional regulator, PmrA, QseB can direct some modifications on the LPS. In agreement with this observation, transcriptional profiling analyses demonstrate regulatory overlaps between PmrA and QseB in terms of regulating LPS modification genes. However, both PmrA and QseB must be present for UPEC to mount robust tolerance to polymyxin B. Transcriptional and metabolomic analyses also reveal that QseB transcriptionally regulates the metabolism of glutamate and 2-oxoglutarate, which are consumed and produced during the modification of lipid A. We show that deletion of qseB alters glutamate levels in the bacterial cells. The qseB deletion mutant, which is susceptible to positively charged antibiotics, is rescued by exogenous addition of 2-oxoglutarate. These findings uncover a previously unknown mechanism of metabolic control of antibiotic tolerance that may be contributing to antibiotic treatment failure in the clinic.

IMPORTANCE

Although antibiotic prescriptions are guided by well-established susceptibility testing methods, antibiotic treatments oftentimes fail. The presented work is significant, because it uncovers a mechanism by which bacteria transiently avoid killing by antibiotics. This mechanism involves two closely related transcription factors, PmrA and QseB, which are conserved across Enterobacteriaceae. We demonstrate that PmrA and QseB share regulatory targets in lipid A modification pathway and prove that QseB can orchestrate modifications of lipid A in E. coli in the absence of PmrA. Finally, we show that QseB controls glutamate metabolism during the antibiotic response. These results suggest that rewiring of QseB-mediated metabolic genes can lead to stable antibiotic resistance in subpopulations within the host, thereby contributing to antibiotic treatment failure.

152 EXPLORATORY ANALYSIS OF TROPONIN AS BIOMARKER OF ACUTE ISCHAEMIC STROKE SUBTYPES IN A GROUP OF PATIENTS RECRUITED TO THE MIND STUDY

Background

Stroke is a major common cause of acquired disability and death worldwide. Atrial dysfunction or cardiomyopathy, defined by the presence of specific serum biomarkers, ECG findings, or echocardiographic findings, increases the risk of atrial fibrillation, which has been implicated as a key risk factor for ischaemic stroke. There is now growing body of evidence which suggests that early positive troponin after ischaemic stroke may be independently associated with a cardiac embolic source. miRNA as Novel Diagnostic biomarker (MiND) is a current Irish-led research study whose aim is to discover a unique highly diagnostic and prognostic biomarker expressed in acute ischaemic stroke.

Methods

Data were retrospectively extracted from patients recruited to the MiND study with confirmed diagnosis of acute ischaemic stroke within 12 hours of symptoms onset having also undergone high-sensitivity troponin testing from July 2019 to November 2021. Stroke subtypes were classified as per ESUS criteria. Statistical analysis was carried out using STATA/SE, version 16.0.

Results

We identified 52 patients who had troponin performed within 12 hours of symptoms onset. Twenty-two patients were identified as having cardioembolic stroke (CE), 17 as non-cardioembolic stroke (NCE) and 13 as Embolic stroke of unknown source (ESUS). The mean age for each group was 77.5 (±9.8), 65.5 (±12.8) and 66.3 (±11.7) years, respectively. The rate of troponin positivity for each group was 55% (12/22), 29% (5/17) and 15% (2/13), respectively. The unadjusted logistic analysis revealed a positive association between CE stroke subtype and elevated troponin (OR 3.94, 95% 1.20-12.98, p = 0.024) and an inverse association between ESUS stroke subtype and elevated troponin (OR 0.24, 95% CI 0.05-1.21, p = 0.083).

Conclusion

Our analysis reveals that early positive troponin after ischaemic stroke is a strong predictor of CE stroke subtype but not of ESUS stroke subtype.

119 ENHANCING THE QUALITY OF STROKE CARE IN IRELAND - DEVELOPMENT OF AN IRISH NATIONAL STROKE AUDIT

Background

Population ageing, stroke treatment advances, changing models of care, and between-hospital heterogeneity in stroke outcomes demonstrate the necessity of continual audit of stroke care to support quality improvement at local and national levels, and to enhance patient recovery and wellbeing. This project aims to identify the core minimum datasets for acute and non-acute stroke care, and Patient-Reported Outcome Measures (PROMs), for integration in to the newly-developed Irish National Audit of Stroke (INAS), in addition to identifying resourcing needs and implementation procedures.

Methods

In Phase 1, a minimum dataset for acute stroke care was identified based on a scoping review of international practice and available guidelines. Phase 2 (ongoing) involves identifying datasets for non-acute rehabilitative and follow-up care based on a scoping review of international practice, iterative cycles of qualitative stakeholder engagement, and systematic review of PROMs. In Phase 3, a review of resourcing and data collection procedures used in stroke audits internationally will be used to produce an implementation strategy for data collection, contextualised to the Irish healthcare system.

Results

Twenty-one eligible international stroke registries were identified from the scoping review. Within Phase 1, core clinical and thrombectomy items in the Irish registry were benchmarked against internationally-collected items to identify common items and to generate an inventory of items that other registries collect that Ireland does not. Based on consensus agreement on the most frequently-occurring international items, as reviewed by key stakeholders, a core minimum dataset for audit of acute stroke care was delivered.

Conclusion

These minimum datasets shall act as the “gold standard” for evaluating stroke care in Ireland, by not only incorporating structure, process, and care quality outcome indicators, but also PROMs. The resultant datasets may inform policy and quality improvement initiatives, and shape health service delivery across the trajectory of stroke care, from hyper-acute care, to rehabilitation, and return to the community.

Nosocomial acquisition of influenza is associated with significant morbidity and mortality: Results of a prospective observational study

BACKGROUND

Nosocomial acquisition of influenza is known to occur but the risk after exposure to a known case and the outcomes after acquisition are poorly defined.

METHODS

Prospective observational study of patients exposed to influenza from another patient in a multi-site healthcare organisation, with follow-up of 7 days or until discharge, and PCR-confirmation of symptomatic disease. Multivariable analysis was used to investigate association of influenza acquisition with high dependency unit/intensive care unit (HDU/ITU) admission and in-hospital mortality.

RESULTS

23/298 (7.7%) contacts of 11 cases were subsequently symptomatic and tested influenza-positive during follow-up. HDU/ITU admission was significantly higher in these secondary cases (6/23, 26%) compared to flu-negative contacts (20/275, 7.2%; p = 0.002). In-hospital mortality was significantly higher in secondary cases (5/23, 21.7%) compared to flu-negative contacts (11/275, 4%; p < 0.001). In multivariable analysis, age (OR 1.25 95% CI: 1.01-1.54, p = 0.02) and being a secondary case (OR 4.77, 95% CI: 1.63-13.9, p = 0.008) were significantly associated with HDU/ITU admission in contacts. Age (OR 1.00, 95% CI: 0.93-1.00, p = 0.02), being a secondary case after exposure to influenza (OR 3.81, 95% CI 1.09-13.3, p = 0.049) and co-morbidity (OR 1.29 per unit increment in the Charlson score, 95% CI 1.02-1.61, p = 0.03) were significantly associated with in-hospital mortality in contacts.

CONCLUSIONS

Nosocomial acquisition of influenza was significantly associated with increased risk of HDU/ITU admission and in-hospital mortality.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

Evolving fetal phenotypes and clinical impact of progressive prenatal exome sequencing pathways: cohort study

OBJECTIVES

To determine (1) the diagnostic yield and turnaround time (TAT) of two consecutive prenatal exome sequencing (ES) pathways, (2) the evolution of the fetal phenotype and (3) the clinical impact of detecting causative pathogenic variants and incidental findings.

METHODS

This was a retrospective cohort analysis of prospectively collected fetal cases that underwent trio ES in the presence of a structural anomaly and normal chromosomal microarray testing in the West Midlands Regional Genetics Laboratory, Birmingham, UK. The study included two phases: (1) between July 2018 and October 2020, the clinical pathway from the Prenatal Assessment of Genomes and Exomes (PAGE) study was adopted and involved prenatal trio ES based on a panel of 1542 development disorder genes and case selection by a multidisciplinary team; (2) between October 2020 and July 2021, prenatal trio ES investigation was based on the National Health Service (NHS) England R21 pathway, with definitive inclusion criteria and a panel of 1205 prenatally relevant genes. Deep phenotyping was performed throughout pregnancy and postnatally.

RESULTS

A total of 54 cases were included. The diagnostic yield before vs after R21 pathway implementation was 28.0% (7/25) and 55.2% (16/29), respectively (P = 0.04). The respective values for mean TAT were 54.0 days (range, 14-213 days) and 14.2 days (range, 3-29 days). In cases in which a causative pathogenic variant was identified and in which the pregnancy reached the third trimester, additional anomalies were detected between the second and third trimesters in 73.3% (11/15) of cases, predominantly secondary to progressive hydropic features (3/11 (27.3%)), arthrogryposis (3/11 (27.3%)) or brain anomaly (2/11 (18.2%)). In three cases, a variant of uncertain significance was reclassified to likely pathogenic based on postnatal information. Detection of a causative pathogenic variant had a significant clinical impact in 78.3% (18/23) of cases, most frequently affecting decision-making regarding the course of the pregnancy and neonatal management (7/18 (38.9%)).

CONCLUSIONS

Prenatal ES using the NHS England R21 pathway showed great promise when applied to this cohort, allowing a genetic diagnosis to be made in over half of preselected cases with a fetal structural anomaly on ultrasound. Monitoring and real-time updating of fetal phenotype and reclassification of variants based on postnatal findings is vital to increase the clinical impact that is already evident from this emerging genomic technology. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

POS0579 ABSENCE OF ASSOCIATION BETWEEN ABATACEPT EXPOSURE LEVELS AND INITIAL INFECTION IN PATIENTS WITH RA: A POST HOC ANALYSIS OF THE RANDOMIZED, PLACEBO-CONTROLLED AVERT-2 STUDY

Background

Infections are the most commonly reported AE observed in patients with RA treated with immunosuppressive therapies and can be clinically significant. A recent review reported differences in the risk of infection for some biologics such as tocilizumab and TNF inhibitors.1 Abatacept selectively modulates T-cell co-stimulation and is approved for the treatment of RA. In patients with polyarticular-course juvenile idiopathic arthritis, no association was found between higher serum abatacept exposure and the incidence of infection.2 This has not been evaluated for adult patients with RA.

Objectives

To determine if higher serum abatacept exposure during treatment with SC abatacept was associated with increased risk of infection in adult patients with RA.

Methods

AVERT-2 (Assessing Very Early Rheumatoid arthritis Treatment-2) was a randomized, placebo-controlled study of SC abatacept + MTX vs abatacept placebo + MTX in MTX-naive, anti-citrullinated protein antibody–positive patients with early, active RA.3 A post hoc population pharmacokinetic (PK) analysis was performed using PK-evaluable patient data from the induction period (year 1) of AVERT-2. Association between steady-state abatacept exposure (min plasma concentration [Cmin], max plasma concentration [Cmax], and average plasma concentration [Cavg]) and first infection was evaluated using Kaplan–Meier plots of probability vs time on treatment by abatacept exposure quartiles and Cox proportional-hazards models.

Results

PK of SC abatacept was defined as a linear 2-compartment model with first-order absorption and first-order elimination. The findings of the updated PK analysis were consistent with those reported in prior population analyses of abatacept PK in adults with RA. The final model included effects of baseline body weight, estimated glomerular filtration rate, sex, age, albumin, MTX use, NSAID use, SJC, and race on abatacept clearance. The only covariate with a clinically relevant effect was higher body weight, which caused an increase in clearance and volume. Infections occurred in a total of 330/693 (47.6%; serious, 1.6%) patients treated with abatacept, and 134/301 (44.5%; serious, 1.3%) with placebo during the first year of AVERT-2. In patients taking abatacept, the mean (SD) study exposure to abatacept was 376 (60) days, while mean (SD) prednisone equivalent dose was 6.7 (3.8) mg/day and mean (SD) MTX dose was 9.6 (3.0) mg/week. No exposure–response relationship was observed between the probability of first infection and steady-state abatacept exposure quartiles (Cavg, Cmin, and Cmax), or compared with placebo (Figure 1A–C). Kaplan–Meier assessment also showed no increase in risk of infection with concomitant use of MTX and glucocorticoids.

Conclusion

No association was found between initial infection and steady-state abatacept exposure (Cavg, Cmin, Cmax) or MTX and glucocorticoid use in patients with RA treated with SC abatacept.

References

[1]Jani M, et al. Curr Opin Rheumatol 2019;31:285–92.

[2]Ruperto N, et al. J Rheumatol 2021;48:1073–81.

[3]Emery P, et al. Arthritis Rheumatol 2019;71(suppl 10):L11.

Acknowledgements

This study was sponsored by Bristol Myers Squibb. Writing and editorial assistance were provided by Fiona Boswell, PhD, of Caudex, and was funded by Bristol Myers Squibb. Support was provided by Sandra Overfield as Protocol Manager, and Prema Sukumar and Renfang Hwang as Data Science Leads.

Disclosure of Interests

Paul Emery Consultant of: AbbVie, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Eli Lilly, Galapagos, Gilead, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Roche, Samsung, Grant/research support from: AbbVie, Bristol Myers Squibb, Eli Lilly, Novartis, Pfizer, Roche, Samsung, Roy Fleischmann Consultant of: Amgen, AbbVie, Bristol Myers Squibb, Gilead, GlaxoSmithKline, Novartis, Pfizer, Grant/research support from: Amgen, AbbVie, Arthrosi, Biosplice, Bristol Myers Squibb, Gilead, GlaxoSmithKline, Horizon, Novartis, Pfizer, Regeneron, TEVA, UCB, Robert Wong Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Karissa Lozenski Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Yoshiya Tanaka Speakers bureau: AbbVie, Amgen, Astellas, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Chugai, Eisai, Eli Lilly, Gilead, Mitsubishi Tanabe, YL Biologics, Consultant of: AbbVie, Ayumi, Daiichi Sankyo, Eli Lilly, GlaxoSmithKline, Taisho, Sanofi, Grant/research support from: AbbVie, Asahi Kasei, Boehringer Ingelheim, Chugai, Corrona, Daiichi Sankyo, Eisai, Kowa, Mitsubishi Tanabe, Takeda, Vivian Bykerk Consultant of: Amgen, Bristol Myers Squibb, Genzyme Corporation, Gilead, Regeneron, UCB, Grant/research support from: Amgen, Bristol Myers Squibb, Genzyme Corporation, Pfizer, Regeneron, Sanofi Aventis, UCB, Clifton Bingham Consultant of: AbbVie, Bristol Myers Squibb, Eli Lilly, Janssen, Pfizer, Sanofi, Grant/research support from: Bristol Myers Squibb, Thomas Huizinga Speakers bureau: Abblynx, Abbott, Biotest AG, Bristol Myers Squibb, Crescendo Bioscience, Eli Lilly, Epirus, Galapagos, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi- Aventis, UCB, Consultant of: Abblynx, Abbott, Biotest AG, Bristol Myers Squibb, Crescendo Bioscience, Eli Lilly, Epirus, Galapagos, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi- Aventis, UCB, Grant/research support from: Abblynx, Abbott, Biotest AG, Bristol Myers Squibb, Crescendo Bioscience, Eli Lilly, Epirus, Galapagos, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi- Aventis, UCB, Gustavo Citera Speakers bureau: AbbVie, Amgen, Bristol Myers Squibb, Eli Lilly, Janssen, Pfizer, Sandoz, Consultant of: AbbVie, Amgen, Bristol Myers Squibb, Pfizer, Grant/research support from: Pfizer, Yedid Elbez Consultant of: Bristol Myers Squibb, Employee of: Signifience, Vidya Perera Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Bindu Murthy Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Kelly Maxwell Consultant of: Bristol Myers Squibb, Employee of: Cognigen Corporation, Julie Passarell Consultant of: Bristol Myers Squibb, Employee of: Cognigen Corporation, William Hedrich: None declared, Daphne Williams Consultant of: Black Diamond Network, Joule, Syneos, Employee of: Bristol Myers Squibb.

The structure of the Physcomitrium patens photosystem I reveals a unique Lhca2 paralogue replacing Lhca4

The moss Physcomitrium patens diverged from green algae shortly after the colonization of land by ancient plants. This colonization posed new environmental challenges, which drove evolutionary processes. The photosynthetic machinery of modern flowering plants is adapted to the high light conditions on land. Red-shifted Lhca4 antennae are present in the photosystem I light-harvesting complex of many green-lineage plants but absent in P. patens. The cryo-EM structure of the P. patens photosystem I light-harvesting complex I supercomplex (PSI-LHCI) at 2.8 Å reveals that Lhca4 is replaced by a unique Lhca2 paralogue in moss. This PSI-LHCI supercomplex also retains the PsaM subunit, present in Cyanobacteria and several algal species but lost in vascular plants, and the PsaO subunit responsible for binding light-harvesting complex II. The blue-shifted Lhca2 paralogue and chlorophyll b enrichment relative to flowering plants make the P. patens PSI-LHCI spectroscopically unique among other green-lineage supercomplexes. Overall, the structure represents an evolutionary intermediate PSI with the crescent-shaped LHCI common in vascular plants, and contains a unique Lhca2 paralogue that facilitates the moss's adaptation to low-light niches.

Pregnancy rates and outcomes in women with cystic fibrosis in the UK: comparisons with the general population before and after the introduction of disease-modifying treatment, 2003-17

OBJECTIVE

To compare pregnancy rates and outcomes for women with cystic fibrosis in the UK with those of the general population and assess the effect of the introduction of disease-modifying treatment.

DESIGN

A population-based longitudinal study, 2003-17.

SETTING

United Kingdom.

POPULATION

Women aged 15-44 years in the UK cystic fibrosis (CF) Registry compared with women in England and Wales.

METHODS

We calculated pregnancy and live-birth rates for the CF population and the general population of England and Wales. For women with CF we compared pregnancy rates before and after ivacaftor was introduced in 2013. We further used CF registry data to assess pregnancy outcomes for mothers with CF, and to assess the relationship between maternal pre-pregnancy lung function and nutritional status and child gestational age.

MAIN OUTCOME MEASURES

Pregnancy and live-birth rates and child gestational age.

RESULTS

Of 3831 women with CF, 661 reported 818 pregnancies. Compared with the general population, the pregnancy rate was 3.3 times lower in the CF population (23.5 versus 77.7 per 1000 woman-years); the live-birth rate was 3.5 times lower (17.4 versus 61.4 per 1000 woman-years) with 70% of pregnancies in CF women resulting in live births; termination of pregnancy rates were also lower (9% versus 22%). Pregnancy rates increased post-ivacaftor for eligible women with CF, from 29.7 to 45.7 per 1000 woman-years. There was no association between pre-pregnancy lung function/nutrition status and gestational age.

CONCLUSIONS

Pregnancy rates in women with CF are about one-third of the rates in the general population with favourable outcomes, and increased for eligible women post-ivacaftor.

TWEETABLE ABSTRACT

Pregnancy rates in women with CF are about a third of the rate in England and Wales with 70% live births. Ivacaftor increases the rate.

Outcomes following biosimilar TNF inhibitors use for inflammatory-mediated immune disorders in pregnancy

Background

Biosimilar tumour necrosis factor inhibitors (TNFi) are increasingly used to treat inflammatory immune-mediated disorders as they cost less than the originator biologic drug. More women are therefore becoming pregnant on biosimilar TNFi. This is the first paper to explore the safety and efficacy of biosimilar therapies in pregnancy.

Methods

A retrospective review of clinical data reviewed pregnancy outcomes and inflammatory disease activity in 18 pregnancies where the mother was using a biosimilar TNFi at conception.

Results

Biosimilar therapy was not associated with congenital abnormalities, preterm birth or other adverse pregnancy outcomes. Stopping biosimilar TNFi in pregnancy was associated with childbirth at an earlier gestation, as well as a flare of inflammatory disease in pregnancy or post-partum.

Conclusions

Women and clinicians should feel confident in using biosimilar TNFi in early pregnancy, and continuing them through pregnancy to prevent flares in late pregnancy or the early post-partum.

Impacts on staff after implementation of a respiratory protection program in a Victorian public hospital

BACKGROUND

In October 2020, the Royal Melbourne Hospital implemented a Respiratory Protection Program (RPP), which was initiated by the Victorian Government. This study was to evaluate the effectiveness of the program.

METHODS

A cohort of 158 employees, who were identified as high risk to respiratory biohazard exposure, were invited to participate in the RPP. We provided a bundle of interventions, which included an online training package, and mandatory quantitative fit testing. The main outcomes included the participants' knowledge and attitude toward respiratory protection equipment (RPE), which were assessed via an online survey. Their donning and doffing skills, and user seal check techniques on four different types of N95 respirators were also assessed by an observer using a pre-determined marking sheet. We compared these outcomes before and after participation in the program.

RESULTS

There was a total of 125 participants, all of whom completed the knowledge and attitude assessment, and 69 completed the skill assessment before and after the program. There was a statistically significant improvement in their knowledge scores, donning and doffing skills, and user seal check techniques after participation in the RPP. Participants also reported significant increased level of confidence in their RPE knowledge, training and skills; and workplace safety.

CONCLUSION

This initial report of the implementation of a novel RPP in a Victorian major tertiary hospital provides guidance on the benefits to respiratory protection, staff knowledge, skills, confidence and morale that can be acquired from a scalable online training package combined with mandatory quantitative fit testing.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Development and validation of the Physician's Global Assessment of Fingernail Psoriasis

BACKGROUND

Several clinician-rated scoring systems are available to assess nail psoriasis severity, but only one has been partially validated.

OBJECTIVE

To develop and validate the Physician's Global Assessment of Fingernail Psoriasis (PGA-F), a new clinician-rated severity scale.

METHODS

A literature review, concept elicitation, pilot cognitive debriefing and clinical expert consultations informed the development of the PGA-F. A multistage mixed-methods analysis consisted of practising dermatologist cognitive interviews (n = 10) for instrument clarity, relevance and comprehensiveness. Inter-rater reliability (IRR) of ratings from dermatologists (n = 22) and clinical trial investigators (n = 8) was tested using many-facet Rasch analysis. Concurrent validity between the PGA-F and modified Nail Psoriasis Severity Index (mNAPSI) at screening and baseline was assessed along with the degree of discrimination. Intraclass correlation coefficient (ICC) for single raters at multiple assessments determined IRR.

RESULTS

The PGA-F synthesizes severity ratings across multiple disease features that classify individuals into 1 of 5 levels (clear to severe). Cognitive interviews confirmed content validity: all (n = 10, 100%) participants who agreed clinical criteria were consistent with nail psoriasis; no mismatched severity levels; and training photographs were realistic representations. All PGA-F items were locally independent and targeted patients along the severity continuum with complementary precision (item fit statistics: < the 1.5 acceptability threshold; exact agreements among the dermatologists [44%] and trial investigators [61.5%] exceeded 40% of acceptability threshold). Clinician reliability exceeded the threshold of acceptability for dermatologists and clinical trial investigators: 0.85 and 0.73, respectively. There was adequate correlation (>0.30) between mNAPSI and PGA-F at baseline and Week 26 with significant discrimination of severity and monotonic increases in the mNAPSI for each level of categorical severity on the PGA-F. ICC results for each type of IRR indicate that clinicians were consistent in individual patient ratings.

CONCLUSION

The PGA-F is a rapid, valid and reliable clinician-rated severity scale for use in clinical practice and research.

Inflammatory cytokines, high-sensitivity C-reactive protein, and risk of one-year vascular events, death, and poor functional outcome after stroke and transient ischemic attack

Background

Inflammation driven by pro-inflammatory cytokines is a new therapeutic target in coronary disease. Few data exist on the association of key upstream cytokines and post-stroke recurrence. In a prospective cohort study, we investigated the association between pivotal cytokines, high-sensitivity C-reactive protein (hsCRP) and one-year outcomes.

Methods

BIO-STROKETIA is a multi-center prospective cohort study of non-severe ischemic stroke (modified Rankin score ≤ 3) and transient ischemic attack. Controls were patients with transient symptoms attending transient ischemic attack clinics with non-ischemic final diagnosis. Exclusion criteria were severe stroke, infection, and other pro-inflammatory disease; hsCRP and cytokines (interleukin (IL) 6, IL-1β, IL-8, IL-10, IL-12, interferon-γ (IFN-γ), tumor-necrosis factor-α (TNF-α)) were measured. The primary outcome was one-year recurrent stroke/coronary events (fatal and non-fatal).

Results

In this study, 680 patients (439 stroke, 241 transient ischemic attack) and 68 controls were included. IL-6, IL-1β, IL-8, IFN-γ, TNF-α, and hsCRP were higher in stroke/transient ischemic attack cases (p ≤ 0.01 for all). On multivariable Cox regression, IL-6, IL-8, and hsCRP independently predicted one-year recurrent vascular events (adjusted hazard ratios (aHR) per-quartile increase IL-6 1.31, confidence interval (CI) 1.02–1.68, p = 0.03; IL-8 1.47, CI 1.15–1.89, p = 0.002; hsCRP 1.28, CI 1.01–1.62, p = 0.04). IL-6 (aHR 1.98, CI 1.26–3.14, p = 0.003) and hsCRP (aHR 1.81, CI 1.20–2.74, p = 0.005) independently predicted one-year fatality. IL-6 and hsCRP (adjusted odds ratio per-unit increase 1.02, CI 1.01–1.04) predicted poor functional outcome, with a trend for IL-1β (p = 0.054).

Conclusion

Baseline inflammatory cytokines independently predicted late recurrence, supporting a rationale for randomized trials of anti-inflammatory agents for prevention after stroke and suggesting that targeted therapy to high-risk patients with high baseline inflammation may be beneficial.

Indoor heat exposure in Baltimore: does outdoor temperature matter?

Heat exposure of a population is often estimated by applying temperatures from outdoor monitoring stations. However, this can lead to exposure misclassification if residents do not live close to the monitoring station and temperature varies over small spatial scales due to land use/built environment variability, or if residents generally spend more time indoors than outdoors. Here, we compare summertime temperatures measured inside 145 homes in low-income households in Baltimore city with temperatures from the National Weather Service weather station in Baltimore. There is a large variation in indoor temperatures, with daily-mean indoor temperatures varying from 10 °C lower to 10 °C higher than outdoor temperatures. Furthermore, there is only a weak association between the indoor and outdoor temperatures across all houses, indicating that the outdoor temperature is not a good predictor of the indoor temperature for the residences sampled. It is shown that much of the variation is due to differences in the availability of air conditioning (AC). Houses with central AC are generally cooler than outdoors (median difference of - 3.4 °C) while those with no AC are generally warmer (median difference of 1.4 °C). For the collection of houses with central or room AC, there is essentially no relationship between indoor and outdoor temperatures, but for the subset of houses with no AC, there is a weak relationship (correlation coefficient of 0.36). The results presented here suggest future epidemiological studies of indoor exposure to heat would benefit from information on the availability of AC within the population.

Evidence to Support the Clinical Utility of Prenatal Exome Sequencing in Evaluation of the Fetus with Congenital Anomalies: Scientific Impact Paper No. 64 [February] 2021

Structural differences (congenital anomalies) in the makeup of the baby's heart, brain and other organs are found on antenatal ultrasound scans in up to 3% of pregnancies. These often have a genetic cause, arising because of changes in the chromosomes (which store our genetic material) or the DNA code that make up the genes. The more differences a baby has the more likely the risk of underlying genetic disease. If a structural difference is found, parents are usually offered a genetic test, which may be carried out on cells taken either from the placenta (chorionic villous sampling) or the fluid surrounding the baby (amniocentesis). At the moment, these cells are only tested for changes in the chromosomes and are only able to reveal the underlying cause in about 40% of unborn babies. Prenatal exome sequencing (ES) is a new genetic test, which, when combined with testing the DNA of both parents can find changes in the baby's genetic code. If a DNA change is found that can explain the structural changes seen on ultrasound, specific information about the underlying diagnosis can be given to the parents. Having this information can help parents make important decisions about their ongoing pregnancy, as well as help doctors to care for the mother and baby. Finding a genetic change can also help to understand how the condition has arisen and whether it might happen again in another pregnancy. It may also be possible to test for the genetic condition in future pregnancies. Although prenatal ES is an exciting new way to improve diagnosis rates for structural differences, it has some challenges. While the test is very detailed, it may not always find a genetic explanation and sometimes the results are difficult to interpret. For example, genetic changes can be found where their significance for the pregnancy is unclear. More recently, two studies have now shown that prenatal ES can find a genetic diagnosis in at least 10% of pregnancies with structural differences where standard chromosome testing has been negative. This paper reviews these studies, along with earlier evidence on ES and provides clinicians with guidance for future practice.

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Impact heat driven volatile redistribution at Occator crater on Ceres as a comparative planetary process

Hydrothermal processes in impact environments on water-rich bodies such as Mars and Earth are relevant to the origins of life. Dawn mapping of dwarf planet (1) Ceres has identified similar deposits within Occator crater. Here we show using Dawn high-resolution stereo imaging and topography that Ceres' unique composition has resulted in widespread mantling by solidified water- and salt-rich mud-like impact melts with scattered endogenic pits, troughs, and bright mounds indicative of outgassing of volatiles and periglacial-style activity during solidification. These features are distinct from and less extensive than on Mars, indicating that Occator melts may be less gas-rich or volatiles partially inhibited from reaching the surface. Bright salts at Vinalia Faculae form thin surficial precipitates sourced from hydrothermal brine effusion at many individual sites, coalescing in several larger centers, but their ages are statistically indistinguishable from floor materials, allowing for but not requiring migration of brines from deep crustal source(s).

Using social media for smoking cessation interventions: a systematic review

Background:

Previous studies have shown that smoking tobacco significantly increases both incidence and mortality rates for many diseases. Social media has become one of the most influential platforms for various smoking cessation interventions. However, results from smoking cessation interventions have differed from study to study. Limited studies have summarised cessation outcomes from social media–based interventions. Therefore, the objective of this review is to explore the effectiveness of using social media for smoking cessation.

Methods:

We searched PubMed, MEDLINE, PsycINFO, and CINAHL for articles between June 2008 and June 2018, and also assessed the references of selected articles. We included studies that used social media as intervention platforms, provided a baseline assessment before the intervention, and provided smoking cessation outcomes after the intervention.

Results:

We identified 13 original studies that enrolled between 16 and 1698 participants; 7-day Point Prevalence Abstinence (PPA) rate was the most frequently used measure of abstinence, with a range of 7%–75%, regardless of the measurement time, study design, and analysis methods. Social media–based smoking cessation interventions were effective, because (1) smokers reported higher 7-day PPA rates after intervention compared to baseline and (2) smokers reported higher 7-day PPA rates in intervention groups than in control groups. Moreover, at each time point, approximately half of all smokers in studies reporting abstinence were found to be biochemically abstinent. There were no significant differences in the effectiveness of smoking cessation outcomes between those that used existing popular social networking platforms (e.g. Pechmann et al’s studies) and those that used individually designed interactive platforms (e.g. MyLastDip, iQuit system, Quitxt system).

Conclusions:

This review highlights the effectiveness of social media–based smoking cessation intervention studies. Due to the widespread use of social media, as well as its low cost, we suggest embedding smoking cessation interventions within existing popular social media platforms.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

Early safety of tenofovir alafenamide in patients with a history of tubulopathy on tenofovir disoproxil fumarate: a randomized controlled clinical trial

OBJECTIVES

The aim of the study was to assess the effect of tenofovir alafenamide (TAF) on kidney and bone biomarkers in patients who developed proximal renal tubulopathy (PRT) while receiving tenofovir disoproxil fumarate (TDF).

METHODS

Individuals with a history of TDF-associated PRT and currently suppressed HIV infection on a tenofovir-sparing regimen were randomized 1:1 to continue current antiretroviral therapy or initiate emtricitabine (F)/TAF with discontinuation of nucleoside reverse transcriptase inhibitors (NRTIs) as appropriate. Renal and bone biomarkers were analysed at baseline, week 4 and week 12. The primary outcome was the mean difference between study arms in urine retinol-binding protein:creatinine ratio (RBPCR) change from baseline to week 12. Data were analysed using linear regression, with robust standard errors (primary outcome), and repeated measures mixed effects models (secondary outcomes). The trial was registered under European Union Drug Regulating Authorities Clinical Trials Database 2016-003345-29.

RESULTS

We randomized 31 individuals [mean age 52.4 (standard deviation 0.3) years; 97% male; 90% white); all completed the study. At 12 weeks, there was no difference in change in RBPCR (β 19.6; 95% confidence interval -35.3, 74.5; P = 0.47), and no difference in change in estimated glomerular filtration rate (eGFR) (based on creatinine or cystatin C), albuminuria, proteinuria, renal phosphate or urea handling, (fasting) urine osmolality, parathyroid hormone and bone turnover markers in the control versus the F/TAF exposed groups. No cases of PRT were observed.

CONCLUSIONS

In people with a history of proximal renal tubulopathy while on TDF, 12-week exposure to TAF did not adversely affect renal tubular function. These data support continued evaluation of the long-term safety of TAF in this group of patients.

Birth outcomes in women with gestational diabetes managed by lifestyle modification alone: The PANDORA study

AIMS

To assess outcomes of women in the Pregnancy and Neonatal Diabetes Outcomes in Remote Australia (PANDORA) cohort with gestational diabetes mellitus (GDM) managed by lifestyle modification compared with women without hyperglycaemia in pregnancy.

METHODS

Indigenous (n = 97) and Europid (n = 113) women managed by lifestyle modification were compared to women without hyperglycaemia (n = 235). Multivariate linear and logistic regressions assessed whether GDM-lifestyle women had poorer outcomes compared to women without hyperglycaemia.

RESULTS

Women with GDM-lifestyle had higher body mass index and lower gestational weight gain than women without hyperglycaemia. On univariate analysis, gestational age at delivery was lower and induction rates were higher in women with GDM-lifestyle than without hyperglycaemia. On multivariable regression, GDM-lifestyle was associated with lower gestational age at delivery (by 0.73 weeks), lower birthweight z-score (by 0.26, p = 0.007), lower likelihood of large for gestational age (LGA) [OR (95% CI): 0.55 (0.28, 1.02), p = 0.059], and greater likelihood of labour induction [2.34 (1.49, 3.66), p < 0.001] than women without hyperglycaemia.

CONCLUSION

Women with GDM managed by lifestyle modification had higher induction rates and their offspring had lower birthweight z-scores, with a trend to lower LGA than those without hyperglycaemia in pregnancy. Further studies are indicated to explore reasons for higher induction rates.

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

Translating the Developmental Origins of Health and Disease concept to improve the nutritional environment for our next generations: a call for a reflexive, positive, multi-level approach

Evidence supporting the Developmental Origins of Health and Disease (DOHaD) hypothesis indicates that improving early life environments can reduce non-communicable disease risks and improve health over the lifecourse. A widespread understanding of this evidence may help to reshape structures, guidelines and individual behaviors to better the developmental conditions for the next generations. Yet, few efforts have yet been made to translate the DOHaD concept beyond the research community. To understand why, and to identify priorities for DOHaD Knowledge Translation (KT) programs, we review here a portion of published descriptions of DOHaD KT efforts and critiques thereof. We focus on KT targeting people equipped to apply DOHaD knowledge to their everyday home or work lives. We identified 17 reports of direct-to-public DOHaD KT that met our inclusion criteria. Relevant KT programs have been or are being initiated in nine countries, most focusing on secondary school students or care-workers-in-training; few target parents-to-be. Early indicators suggest that such programs can empower participants. Main critiques of DOHaD KT suggest it may overburden mothers with responsibility for children's health and health environments, minimizing the roles of other people and institutions. Simultaneously, though, many mothers-to-be seek reliable guidance on prenatal health and nutrition, and would likely benefit from engagement with DOHaD KT. We thus recommend emphasizing solidarity, and bringing together people likely to one day become parents (youth), people planning pregnancies, expecting couples, care workers and policymakers into empowering conversation about DOHaD and about the importance and complexity of early life environments.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.