Toward the quantification of α-synuclein aggregates with digital seed amplification assays

The quantification and characterization of aggregated α-synuclein in clinical samples offer immense potential toward diagnosing, treating, and better understanding neurodegenerative synucleinopathies. Here, we developed digital seed amplification assays to detect single α-synuclein aggregates by partitioning the reaction into microcompartments. Using pre-formed α-synuclein fibrils as reaction seeds, we measured aggregate concentrations as low as 4 pg/mL. To improve our sensitivity, we captured aggregates on antibody-coated magnetic beads before running the amplification reaction. By first characterizing the pre-formed fibrils with transmission electron microscopy and size exclusion chromatography, we determined the specific aggregates targeted by each assay platform. Using brain tissue and cerebrospinal fluid samples collected from patients with Parkinson's Disease and multiple system atrophy, we demonstrated that the assay can detect endogenous pathological α-synuclein aggregates. Furthermore, as another application for these assays, we studied the inhibition of α-synuclein aggregation in the presence of small-molecule inhibitors and used a custom image analysis pipeline to quantify changes in aggregate growth and filament morphology.

Early Cancer Detection in Li-Fraumeni Syndrome with Cell-Free DNA

People with Li-Fraumeni syndrome (LFS) harbor a germline pathogenic variant in the TP53 tumor suppressor gene, face a near 100% lifetime risk of cancer, and routinely undergo intensive surveillance protocols. Liquid biopsy has become an attractive tool for a range of clinical applications, including early cancer detection. Here, we provide a proof-of-principle for a multimodal liquid biopsy assay that integrates a targeted gene panel, shallow whole-genome, and cell-free methylated DNA immunoprecipitation sequencing for the early detection of cancer in a longitudinal cohort of 89 LFS patients. Multimodal analysis increased our detection rate in patients with an active cancer diagnosis over uni-modal analysis and was able to detect cancer-associated signal(s) in carriers prior to diagnosis with conventional screening (positive predictive value = 67.6%, negative predictive value = 96.5%). Although adoption of liquid biopsy into current surveillance will require further clinical validation, this study provides a framework for individuals with LFS.

SIGNIFICANCE

By utilizing an integrated cell-free DNA approach, liquid biopsy shows earlier detection of cancer in patients with LFS compared with current clinical surveillance methods such as imaging. Liquid biopsy provides improved accessibility and sensitivity, complementing current clinical surveillance methods to provide better care for these patients. See related commentary by Latham et al., p. 23. This article is featured in Selected Articles from This Issue, p. 5.

Ultrasensitive protein detection technologies for extracellular vesicle measurements

Extracellular Vesicles (EVs) are nanoscopic, heterogenous, lipid-rich particles that carry a multitude of cargo biomolecules including proteins, nucleic acids, and metabolites. Although historically, EVs were regarded as cellular debris with no intrinsic value, growing understanding of EV biogenesis has led to the realization that EVs facilitate intercellular communication and are sources of liquid biomarkers. EVs can be isolated and analyzed from a wide variety of accessible biofluids for biomarker discovery and diagnostic applications. There is a diversity of EVs from different biological compartments (e.g., cells, tissues) and some of these EVs are present at extremely low concentrations. Consequently, a challenge in the field is to find appropriate markers that enable selective isolation of these rare EVs. Many conventional protein detection technologies have limited sensitivity to detect low abundance biomarkers in EVs, limiting their use in EV research. Advances in ultrasensitive detection technologies are needed to harness the potential of EVs for clinical application. This Perspective highlights current EV research focusing on ultrasensitive detection technologies, their limitations, and areas of potential growth in the future.

Delivery outcomes as a result of snoring as determined by standard sleep surveys

Background

Sleep-disordered breathing (SDB), is an umbrella term that encompasses obstructive sleep apnea (OSA), central sleep apnea (CSA) and hypoventilation. is common but studies in the pregnant population are limited. Data suggests relationships between OSA and preeclampsia, but the relationship between snoring and pregnancy outcomes is unknown.

Methods

A prospective study of 2224 singleton pregnancies was undertaken. Women were questioned using the Berlin Questionnaire (BQ- 2 or more categories where the score is positive.) and the Epworth Sleepiness Scale (ESS >10/24), the results compared with pregnancy outcomes with regard to hypertension in pregnancy.

Results

Women having symptoms raising the possibility of OSA defined by the BQ with a score >7 was 45.5%, and using ESS with a score >10, was 36%. The birth and neonatal outcomes for self-reported snoring and increased daytime sleepiness showed increased adverse outcomes notably increased caesarean section rates and low APGAR scores but not birth before 37 weeks of gestation.

Conclusion

Using questionnaires designed for the general population, the prevalence of possible undiagnosed OSA is high in the pregnant population. The increased adverse delivery and neonatal outcomes for self-reported snoring and increased daytime sleepiness with these tools indicated the need for further investigation of the links between snoring SDB and pregnancy outcomes.

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.

Abstract 538: Cell-free whole genome sequencing for the detection of cancer in patients with germline BRCA1/2 mutations

Background: Hereditary breast and ovarian cancer syndrome (HBOC) is caused by a germline likely/pathogenic variant in BRCA1 or BRCA2, leading to increased risk of developing breast, ovarian, prostate, and pancreatic cancers. While HBOC patients often undergo regular surveillance including breast imaging, other cancers have no effective screening or biomarkers. One emerging technology is the analysis of circulating tumor DNA (ctDNA), fragments of DNA that are shed from the tumor into the bloodstream. In sporadic cancer, several studies have demonstrated the advantages and sensitivity of cell-free whole genome sequencing (cfWGS) compared to targeted panel sequencing. However, the use of cfWGS for cancer detection in HBOC has not been explored.

Methods: Matched tumor, germline, and plasma were collected from 5 HBOC patients (3 breast, 2 ovarian) as part of the Canada-wide CHARM consortium (https://charmconsortium.ca). Tumor (40x), germline (20x), and plasma (20x) underwent whole genome sequencing (WGS) and subsequent variant calling pipeline using an ensemble of 6 variant callers. Insertions, deletions, and structural variants were not included in downstream analyses. Plasma tumor fraction prediction and copy number alterations were performed using ichorCNA. Detection of tumor associated mutations in plasma was compared to MRDetect software.

Results: Variant calling identified an average of 11,170 tumor (7,649-16,706) and 1,215 (544-3,205) plasma SNVs per patient. Somatic BRCA1/2 mutations were detected in 0/5; whereas deletion of the intact BRCA1/2 allele was identified in 5/5 patients. An average of 24.6% (8.3%-75.9%) of plasma mutations where shared with SNVs identified in matched tumor. Targeted panel deep-sequencing (20,000X) was only able to detect mutations in TP53 in 3/5 cases (0.8% - 8.6%). Plasma derived copy number alterations correlated well with tumor derived copy number alterations in 3/5 cases and ichorCNA predicted tumor fractions ranged from 0.038 to 0.196.

Conclusions: Traditionally, targeted panel sequencing has been used to identify tumor associated mutations in plasma. While this technique is sensitive, major disadvantages include the narrow breadth of the captured regions and the inability to detect deletion events such as those that occur in BRCA1/2. Here we show that plasma WGS is effective for detecting tumor associated mutations in HBOC and is more sensitive than targeted panel sequencing. We are currently expanding our cohort to an additional 20 matched tumor pairs, including patients with pre-diagnosis plasma timepoints.

Citation Format: Derek Wong, Adriana Aguilar-Mahecha, Josiane Lafleur, Clarissa Chan, Kirsten Farncombe, Maia Norman, Leslie Oldfield, Prabhjit Basra, Stephanie Pederson, Johanna Wellum, Stephenie Prokopec, Mark Basik, Raymond H. Kim, Trevor Pugh. Cell-free whole genome sequencing for the detection of cancer in patients with germline BRCA1/2 mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 538.

Anatomical variations in coronary venous drainage: challenges and solutions in delivering cardiac resynchronisation therapy

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac resynchronisation therapy (CRT) is the cornerstone of heart failure management. Delivery of a left ventricular lead can occur in a small proportion of patients undermining the benefits of this treatment. Abnormal coronary venous anatomy is a contributing factor to this failure. Although epicardial lead placement is available, this patient cohort requiring CRT is subject to higher peri-operative morbidity and mortality than the general population; a transvenous approach is preferable.

Purpose

To investigate the abnormalities of the coronary venous system in candidates for cardiac resynchronization therapy (CRT) and describe methods for circumventing the resulting difficulties.

Methods

From 4 implanting institutes, data of all CRT implants between October 2008-October 2020 were screened for abnormal cardiac venous anatomy, defined as an anatomical variation not conforming to the accepted ‘normal’ anatomy. Patient demographics, procedural detail and subsequent left ventricle (LV) lead pacing indices were collected.

Results

From a total of 3548 CRT implants, 15 (0.42%) patients (80% male) of 72.2±10.6 years in age with a LV ejection fraction of 34±10.3% were identified to have had an abnormal cardiac venous anatomy over the study period. There were 13 cases of persistent left side superior vena cava (pLSVC), 5 of which had coronary sinus ostium atresia (CSOA) including 2 with an ‘unroofed’ coronary sinus (CS); 1 patient had a unique anomalous origin of the CS and 1 patient had an isolated CSOA. In total 14 patients (60% repeat attempt) had successful percutaneous implant under general anaesthesia (46.7%) via the cephalic vein (59.1%), using the femoral approach (53.3%) for levophase venography and/or pull-through, including 1 case of endocardial LV implant. Pacing follow-up over 37.64±37.6 months demonstrated LV lead threshold between 0.62-2.9 volts (pulsewidth 0.4-1.5 milliseconds) in all cases; 5 patients died within 2.92±1.6 years of successful implant.

Conclusion

CRT devices can be implanted percutaneously even in the presence of substantial abnormalities of coronary venous anatomy. Alternative routes of venous access may be required.

Oesophageal protection during AF ablation: real world registry data and mechanisms behind the therapeutic effect of tissue cooling

Funding Acknowledgements

Type of funding sources: None.

Background

Oesophageal protection using a dedicated device to provide controlled active thermal protection of the oesophagus during atrial fibrillation ablation has been shown to be effective at reducing endoscopically detected oesophageal lesions. Real world registry data of this device and established evidence on the effect of cooling on localized tissue after thermal injury have been under review.

Purpose

To determine the safety of an oesophageal temperature control device by a review of real-world registry data on its clinical use during catheter ablation procedures and to clarify basic mechanisms of its therapeutic action by a literature review of scientific studies on cooling in the context of thermal injury.

Methods

The United States Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE), FDA Medical and Radiation Emitting Device Recalls, the Medicines and Healthcare products Regulatory Agency (MHRA) Medical Device Alerts and SwissMedic records of Field Safety Corrective Actions (FSCA) databases were reviewed for any device-related adverse events. A systematic literature review was conducted to clarify the findings from studies investigating the physiological processes behind the therapeutic effect of cooling after tissue thermal injury.

Results

Of over 20,000 oesophageal temperature control devices clinically used, 7976 were recorded as having been used for the purpose of oesophageal protection during left atrial catheter ablations. No adverse events occurred related to its use during left atrial catheter ablations. No case of clinically significant oesophageal injury was reported in a patient who had been protected by the oesophageal temperature control device. 208 research articles retrieved from PubMed and MEDLINE that met the search criteria were reviewed. The common finding in all the studies was that cooling had an anti-inflammatory and restorative effect via modulation of several immune-mediated pathways, local cellular function and genetic expression.

Conclusions

There have been no adverse events reported to date in real world clinical use of an oesophageal temperature control device during left atrial catheter ablations, for the purpose of active thermal protection. Literature review data suggests that there are complex biophysical and cellular effects from cooling that leads to its therapeutic effect but further work is required to define the mechanisms of action of thermal protection in this specific context.

Randomised comparison of achieve and traditional circular mapping catheters in cryoballoon ablation: results at up to a decade

Funding Acknowledgements

Type of funding sources: None.

Background

A single-centre trial randomised patients to the use of the Achieve mapping catheter or a traditional circular mapping catheter during cryoballoon procedures for paroxysmal atrial fibrillation (AF) in 2011-2014. Long-term outcomes from the cohort were determined in 2021.

Purpose

To evaluate the determinants of long-term outcome of ablation for paroxysmal AF.

Methods

Patient and study procedure characteristics and clinical outcomes were determined, including mapping catheter assignment, model of cryoballoon used, AF recurrence, repeat ablations required, findings at repeat ablation long term survival of the patient.

Results

Of 102 patients in the original study, 98 had long-term (4.11+/-2.82 years) follow up data available. 35 patients (35.7%) had AF recurrence, giving a long-term success rate at 64.3% after 1 ablation, increasing to 81.6% after repeat ablation. Of the study cohort n=8 (8.16%) died at a median of 4.9 years after ablation (IQR:1.7-5.7). 25/98 (25.5%) patients had a second ablation and 7 (7.1%) had a third or more ablations. Those who had AF recurrence were older, with a higher prevalence of prior ischaemic heart disease and cardiac device implantation (p=0.02-0.03). After multi-variate analysis, a prior implanted cardiac device was the only significant predictor of recurrence (p=0.03).

Conclusion

Long-term outcomes after a 1st time PAF cryoablation were similar regardless of the type of mapping catheter used, the generation of cryoballoon, and traditional procedure endpoints. AF recurrences were more often detected in older patients with a history of ischaemic heart disease and implanted cardiac devices.

High-Sensitivity Single Molecule Array Assays for Pathological Isoforms in Parkinson’s Disease

Background

Clinical trials for neurodegenerative diseases are increasingly utilizing measurements of post-translational modifications (PTMs) and pathological isoforms as surrogate markers of target engagement and therapeutic efficacy. These isoforms, however, tend to exist at femtomolar concentrations, well below the detection limit of conventional immunoassays. Therefore, highly sensitive and well-validated assays for these isoforms are needed.

Methods

We developed a novel panel of single molecule array assays for pathological isoforms and PTMs implicated in the development and pathophysiology of Parkinson’s disease. We validated this panel by measuring these analytes in the cerebrospinal fluid of a cross-sectional cohort of 100 patients with Parkinson’s disease and 100 healthy controls.

Results

When comparing patients with Parkinson’s disease to healthy controls, alpha synuclein, pSer129 alpha synuclein, DJ-1, and C-reactive protein were shown to be reduced in patients with Parkinson’s disease while p396 tau and neurofilament light chain were shown to be increased. A random forest analysis produced an area under the curve of 0.70 for the panel.

Conclusions

Measurement of post-translational modifications and pathological isoforms in patients with Parkinson’s disease improved diagnostic accuracy above that of total protein measurements, demonstrating the potential utility of these assays for monitoring patients in clinical trials.

Framework for rapid comparison of extracellular vesicle isolation methods

Extracellular vesicles (EVs) are released by all cells into biofluids and hold great promise as reservoirs of disease biomarkers. One of the main challenges in studying EVs is a lack of methods to quantify EVs that are sensitive enough and can differentiate EVs from similarly sized lipoproteins and protein aggregates. We demonstrate the use of ultrasensitive, single-molecule array (Simoa) assays for the quantification of EVs using three widely expressed transmembrane proteins: the tetraspanins CD9, CD63, and CD81. Using Simoa to measure these three EV markers, as well as albumin to measure protein contamination, we were able to compare the relative efficiency and purity of several commonly used EV isolation methods in plasma and cerebrospinal fluid (CSF): ultracentrifugation, precipitation, and size exclusion chromatography (SEC). We further used these assays, all on one platform, to improve SEC isolation from plasma and CSF. Our results highlight the utility of quantifying EV proteins using Simoa and provide a rapid framework for comparing and improving EV isolation methods from biofluids.

SARS-CoV-2 and pregnancy outcomes under universal and non-universal testing in Sweden: register-based nationwide cohort study

OBJECTIVE

To assess associations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and pregnancy outcomes considering testing policy and test-positivity-to-delivery interval.

DESIGN

Nationwide cohort study.

SETTING

Sweden.

POPULATION

From the Pregnancy-Register we identified 88 593 singleton births, 11 March 2020-31 January 2021, linked to data on SARS-CoV-2-positivity from the Public Health Agency, and information on neonatal care admission from the Neonatal Quality Register. Adjusted odds ratios (aORs) were estimated stratified by testing-policy and test-positivity-to-delivery interval.

MAIN OUTCOME MEASURES

Five-minute Apgar score, neonatal care admission, stillbirth and preterm birth.

RESULTS

During pregnancy, SARS-CoV-2 test-positivity was 5.4% (794/14 665) under universal testing and 1.9% (1402/73 928) under non-universal testing. There were generally lower risks associated with SARS-CoV-2 under universal than non-universal testing. In women testing positive >10 days from delivery, generally no significant differences in risk were observed under either testing policy. Neonatal care admission was more common (15.3% versus 8.0%; aOR 2.24, 95% CI 1.62-3.11) in women testing positive ≤10 days before delivery under universal testing. There was no significant association with 5-minute Apgar score below 7 (1.0% versus 1.7%; aOR 0.64, 95% CI 0.24-1.72) or stillbirth (0.3% versus 0.4%; aOR 0.72, 95% CI 0.10-5.20). Compared with term births (2.1%), test-positivity was higher in medically indicated preterm birth (5.7%; aOR 2.70, 95% CI 1.60-4.58) but not significantly increased in spontaneous preterm birth (2.3%; aOR 1.12, 95% CI 0.62-2.02).

CONCLUSIONS

Testing policy and timing of test-positivity impact associations between SARS-CoV-2-positivity and pregnancy outcomes. Under non-universal testing, women with complications near delivery are more likely to be tested than women without complications, thereby inflating any association with adverse pregnancy outcomes compared with findings under universal testing.

TWEETABLE ABSTRACT

Testing policy and time from SARS-CoV-2 infection to delivery influence the association with pregnancy outcomes.

Ultra-Sensitive Serial Profiling of SARS-CoV-2 Antigens and Antibodies in Plasma to Understand Disease Progression in COVID-19 Patients with Severe Disease

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 21 million people worldwide since August 16, 2020. Compared to PCR and serology tests, SARS-CoV-2 antigen assays are underdeveloped, despite their potential to identify active infection and monitor disease progression.

METHODS

We used Single Molecule Array (Simoa) assays to quantitatively detect SARS-CoV-2 spike, S1 subunit, and nucleocapsid antigens in the plasma of patients with coronavirus disease (COVID-19). We studied plasma from 64 patients who were COVID-19 positive, 17 who were COVID-19 negative, and 34 prepandemic patients. Combined with Simoa anti-SARS-CoV-2 serological assays, we quantified changes in 31 SARS-CoV-2 biomarkers in 272 longitudinal plasma samples obtained for 39 patients with COVID-19. Data were analyzed by hierarchical clustering and were compared to longitudinal RT-PCR test results and clinical outcomes.

RESULTS

SARS-CoV-2 S1 and N antigens were detectable in 41 out of 64 COVID-19 positive patients. In these patients, full antigen clearance in plasma was observed a mean ± 95% CI of 5 ± 1 days after seroconversion and nasopharyngeal RT-PCR tests reported positive results for 15 ± 5 days after viral-antigen clearance. Correlation between patients with high concentrations of S1 antigen and ICU admission (77%) and time to intubation (within 1 day) was statistically significant.

CONCLUSIONS

The reported SARS-CoV-2 Simoa antigen assay is the first to detect viral antigens in the plasma of patients who were COVID-19 positive to date. These data show that SARS-CoV-2 viral antigens in the blood are associated with disease progression, such as respiratory failure, in COVID-19 cases with severe disease.

Evaluation of Three Commercial and Two Non-Commercial Immunoassays for the Detection of Prior Infection to SARS-CoV-2

BACKGROUND

Serological testing provides a record of prior infection with SARS-CoV-2, but assay performance requires independent assessment.

METHODS

We evaluated 3 commercial (Roche Diagnostics pan-IG, and Epitope Diagnostics IgM and IgG) and 2 non-commercial (Simoa and Ragon/MGH IgG) immunoassays against 1083 unique samples that included 251 PCR-positive and 832 prepandemic samples.

RESULTS

The Roche assay registered the highest specificity 99.6% (3/832 false positives), the Ragon/MGH assay 99.5% (4/832), the primary Simoa assay model 99.0% (8/832), and the Epitope IgG and IgM 99.0% (8/830) and 99.5% (4/830), respectively. Overall sensitivities for the Simoa, Roche pan-IG, Epitope IgG, Ragon/MGH IgG, and Epitope IgM were 92.0%, 82.9%, 82.5%, 64.5% and 47.0%, respectively. The Simoa immunoassay demonstrated the highest sensitivity among samples stratified by days postsymptom onset (PSO), <8 days PSO (57.69%) 8-14 days PSO (93.51%), 15-21 days PSO (100%), and > 21 days PSO (95.18%).

CONCLUSIONS

All assays demonstrated high to very high specificities while sensitivities were variable across assays.

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.

Evaluation of serological lateral flow assays for severe acute respiratory syndrome coronavirus-2

BACKGROUND

COVID-19 has resulted in significant morbidity and mortality worldwide. Lateral flow assays can detect anti-Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) antibodies to monitor transmission. However, standardized evaluation of their accuracy and tools to aid in interpreting results are needed.

METHODS

We evaluated 20 IgG and IgM assays selected from available tests in April 2020. We evaluated the assays' performance using 56 pre-pandemic negative and 56 SARS-CoV-2-positive plasma samples, collected 10-40 days after symptom onset, confirmed by a molecular test and analyzed by an ultra-sensitive immunoassay. Finally, we developed a user-friendly web app to extrapolate the positive predictive values based on their accuracy and local prevalence.

RESULTS

Combined IgG + IgM sensitivities ranged from 33.9 to 94.6%, while combined specificities ranged from 92.6 to 100%. The highest sensitivities were detected in Lumiquick for IgG (98.2%), BioHit for both IgM (96.4%), and combined IgG + IgM sensitivity (94.6%). Furthermore, 11 LFAs and 8 LFAs showed perfect specificity for IgG and IgM, respectively, with 15 LFAs showing perfect combined IgG + IgM specificity. Lumiquick had the lowest estimated limit-of-detection (LOD) (0.1 μg/mL), followed by a similar LOD of 1.5 μg/mL for CareHealth, Cellex, KHB, and Vivachek.

CONCLUSION

We provide a public resource of the accuracy of select lateral flow assays with potential for home testing. The cost-effectiveness, scalable manufacturing process, and suitability for self-testing makes LFAs an attractive option for monitoring disease prevalence and assessing vaccine responsiveness. Our web tool provides an easy-to-use interface to demonstrate the impact of prevalence and test accuracy on the positive predictive values.

AB0277 ASSOCIATION BETWEEN INTRA-ERYTHROCYTE METHOTREXATE POLYGLUTAMATE CONCENTRATION AND CLINICAL RESPONSE IN RHEUMATOID ARTHRITIS IN PATIENTS TREATED WITH METHOTREXATE INJECTABLE SUBCUTANEOUSLY

Background:

Methotrexate (MTX) is the first-line treatment for rheumatoid arthritis (RA). Due to its short half-life, blood MTX dosage is not performed in current practice. Erythrocyte MTX-polyglutamate (MTX-PG), which penetrates into the red blood cells, would be correlated with the area under the MTX curve and would be more accessible for dosing. When treatment is initiated, its concentration correlates with efficacy and therapeutic adherence.

Objectives:

To determine the interest of erythrocyte MTX-PG dosage in case of failure of 1st line MTX treatment.

Methods:

In this single-centre cross-sectional study, RA patients presenting for consultation at the Saint-Etienne University Hospital, with a stable dose of MTX for more than 3 months at least 15 mg/week subcutaneously with either clinical remission (DAS28<2.6) or active disease (DAS28>3.2) were included between July 2nd 2018 and May 28th 2020. In order to assess therapeutic compliance, the patient completed the compliance questionnaire of Rheumatology (CQR) questionnaire. The determination of erythrocytic MTX-PG was performed on a 5 mL blood sample by liquid chromatography method for the determination of the different PG forms.

Results:

Sixty patients were included, 34 in the active RA group and 26 in the RA group in remission. One patient withdrew his consent. Only 16% of patients were observed with a CQR score > 80%. Patients in remission were leaner with a longer duration of disease and MTX treatment. The sex ratio, RA status, creatinine clearance and MTX dose was not different in both groups. The CQR was better in the remission group than in the active RA group. However, total MTX-PG was not different in the two groups. The same results were observed for the different forms of MTX-PG 1, 2, 3 or 4. In contrast, in the remission PR group, total MTX-PG or MTX-PG2, 3, 4 and 5 correlated inversely with BMI while MTX-PG3 correlated positively with BMI in the active PR group. In the active PR group, MTX-PG5 correlated with MTX dose.

Conclusion:

MTX-PG dosage is not a biomarker of good response to MTX in our study. However, compliance is a key factor to be considered in RA with active disease in adapting patient management.

References:

[1]Pasma A, Boer E den, Spijker A van ’t, Timman R, Bemt B van den, Busschbach JJV, et al. Nonadherence to disease modifying antirheumatic drugs in the first year after diagnosis: comparing three adherence measures in early arthritis patients. Rheumatology 2016;55:1812–1819.

[2]Haandel L van, Becker ML, Leeder JS, Williams TD, Stobaugh JF. A novel high-performance liquid chromatography/mass spectrometry method for improved selective and sensitive measurement of methotrexate polyglutamation status in human red blood cells. Rapid Commun Mass Spectrom RCM 2009;23:3693–3702.

[3]Dervieux T. Pharmacogenetic and metabolite measurements are associated with clinical status in patients with rheumatoid arthritis treated with methotrexate: results of a multicentred cross sectional observational study. Ann Rheum Dis 2005;64:1180–1185.

Disclosure of Interests:

Marion POUDRET: None declared, Myriam Norman: None declared, Sophie Hodin: None declared, Adamah Stanislas AMOUZOUGAN: None declared, Karima BOUSSOUALIM: None declared, Astrid Coassy: None declared, Tiphany Neel: None declared, THIERRY THOMAS: None declared, Xavier DELAVENNE: None declared, Hubert MAROTTE Speakers bureau: Pfizer, Nordic, Paid instructor for: Amgen, Consultant of: Novartis, Grant/research support from: Nordic

AB0074 NO DIFFERENCE BETWEEN THE SEROLOGIES OF DENTAL GERMS AND THE PHENOTYPES OF SPONDYLOARTHRITIS WITHIN THE DESIR COHORT

Background:

Porphyromonas gingivalis (PG) and Prevotella Intermedia (PI) are two oral pathogens involved in the pathophysiology of chronic periodontopathies. Several studies have determined a role of these periodontal pathologies in the pathophysiology of rheumatoid arthritis (1) while the link with spondyloarthritis is not clearly established with currently contradictory studies (2,3,4).

Objectives:

The purpose of this work is to investigate a link between spondylarthritis and the presence of chronic periodontopathy evaluated by PG and IP serologies.

Methods:

The positivity and quantity of anti-PG and anti-PI antibodies were determined by ELISA method in patients from the DESIR cohort with one of the spondyloarthritis phenotypes compared to patients with common low back pain (n=50) (population control). Patients with spondyloarthritis were classified according to the following phenotypes (diagnosis chosen at 3 years in the DESIR cohort): axial spondylarthritis (n=126), psoriatic rheumatism (n=101), spondyloarthritis associated with chronic inflammatory bowel disease (n=36), undifferentiated spondylitis (n=241), reactive arthritis (n=2), SAPHO (acronym for Synovite, Acne, Pustulose, Hyperostosis and Osteitis. Correlations between patients’ serological status, and smoking status, body mass index and age were sought.

Results:

According to the general characteristics, the control group was significantly older than the axial spondylarthritis (p<0.001), and the psoriatic rheumatism group had a higher body mass index than the control population (p<0.05). The positivity and concentration of anti-PG and anti-PI antibodies were similar between different groups of spondyloarthritis compared to the control group. However, the subgroups “reactive arthritis” and “SAPHO” could not be analyzed due to insufficient staffing. Smoking status and body mass index were not related to antibody concentrations, however there was a statistical correlation between anti-PG antibody concentrations and age. After adjusting on age, there was no difference between the axial spondylarthritis and control groups.

Conclusion:

Our results therefore suggest the absence of a link between periodontal germs involved in chronic periodontopathies and spondyloarthritis, provided that the two phenotypes involving germs in their pathophysiology could not be analyzed. Our results from a population of beginner spondylitis are therefore not in favour of the involvement of oral flora in the pathophysiology of spondyloarthritis, as is the case in rheumatoid arthritis (1). The associations found previously could therefore be favoured by a systemic inflammatory phenomenon. In conclusion, our study suggests no link between chronic periodontopathy and the occurrence of spondyloarthritis. However, the effect of chronic periodontopathy on the evolution of spondylarthritis remains to be explored.

References:

[1]Detert J, Pischon N, Burmester GR, Buttgereit F. The association between rheumatoid arthritis and periodontal disease. Arthritis Res Ther. 2010;12(5):218.

[2]Ratz T, Dean LE, Atzeni F, Reeks C, Macfarlane GJ, Macfarlane TV. A possible link between ankylosing spondylitis and periodontitis: a systematic review and meta-analysis. Rheumatology. 2015;54(3):500-10.

[3]Pischon N, Pischon T, Gülmez E, Kröger J, Purucker P, Kleber B-M, et al. Periodontal disease in patients with ankylosing spondylitis. Ann Rheum Dis. janv 2010;69(01):34-8.

[4]Sezer U, Erciyas K, Pehlivan Y, Üstün K, Tarakçioğlu M, Şenyurt SZ, et al. Serum cytokine levels and periodontal parameters in ankylosing spondylitis: Ankylosing spondylitis and periodontal diseases. J Periodontal Res. juin 2012;47(3):396-401.

Disclosure of Interests:

None declared

Transvenous lead revision for cardiac perforation: a single centre experience

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac perforation is an uncommon but life-threatening complication of cardiac implantable electronic device (CIED) implantation. Management strategy commonly relies on diagnostic Computed Tomography (CT) imaging and cardiac surgery. Emerging evidence has indicated a diversion from this approach. Transvenous culprit lead revision has been shown to be safe and efficacious in limited series.

We sought to evaluate the outcomes of transvenous lead revision in patients with cardiac perforation.

Method

Data was collected retrospectively of patients admitted to a single tertiary centre with CIED-related cardiac perforation between December 2013 – October 2019. Transvenous lead revision was performed as standard with cardiac surgery on standby. Patient demographics, use of CT imaging, method of removal and 30-day outcomes were recorded.

Results

Of the 46 recorded CIED-related cardiac perforations, the majority occurred in female patients (63%) and hypertensives (61%), whilst a proportion had cancer (20%) and ischaemic heart disease (30%). The culprit in most cases was a standard pacing lead (92%) of an active fixation (98%) in the right ventricle (80%) positioned at the ventricular apex (65%). The median time to presentation from implant was 14 days [IQR 4-50 days] with chest pain (44%); abnormal pacing indices was highly prevalent (95%) whilst a pericardial effusion was noted in the majority of cases (57%). CT scanning was performed in 19 cases (41%) for various indications but deemed essential in only 4, all of which had non-diagnostic pacing indices and imaging. Chest X-ray (CXR) found clear perforation, lead displacement or pleural effusion in 74% of cases, whilst an echocardiogram found these in 64% of cases. The culprit lead was replaced in the majority of cases (87%) under local anaesthesia (76%) with surgical backup. The median hospital stay was 7 days [IQR 3-10 days] with zero procedural and 30-day mortality.

Conclusion

Transvenous lead revision for CIED-related cardiac perforation is safe and efficacious. CT modality for diagnostic purposes is useful in providing incremental value in a minority of cases; patients with non-diagnostic pacing parameters and non-CT imaging benefit most from this.

A registry review of 2532 catheter ablations for atrial fibrillation using active thermal protection

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Dr Leung has received research support from Attune Medical (Chicago, IL). Dr Gallagher has received research funding from Attune Medical (Chicago, IL).

Background

  Thermal injury to the oesophagus causes a spectrum of adverse effects after ablation for atrial fibrillation (AF); at the most severe end, atrio-oesophageal fistula carries a high mortality rate. Controlled active thermal protection in the oesophagus during ablation is the most promising method of oesophageal protection. Randomized evidence from the IMPACT trial (NCT03819946) showed an 83.4% reduction in endoscopically detected oesophageal lesions compared to standard care when an oesophageal temperature control device was used to control the local temperature. The IMPACT patients who were randomized to the use of the device had no adverse event related to its use.  Real world registry data on applications of this device have not previously been available. 

Purpose

To determine the safety of an oesophageal temperature control device by review of real-world registry data on its clinical use and any reported device-related adverse events.

Methods

  We reviewed the following databases for any reported oesophageal temperature control device-related complications: The United States Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE), FDA Medical and Radiation Emitting Device Recalls, the Medicines and Healthcare products Regulatory Agency (MHRA) Medical Device Alerts and SwissMedic records of Field Safety Corrective Actions (FSCA). An internal registry (post-marketing follow up) database maintained by the manufacturer of the device was used to quantify the number used for each indication.  Reported events were reviewed and catalogued for description and identification of any events related to its use in the cardiac electrophysiology lab. The IMPACT study patients were reviewed for any device-related events.

Results

  Of the 13, 284 oesophageal temperature control devices used, 2532 were recorded as having been used for the purpose of oesophageal protection during catheter ablation for AF.  A total of 5 events associated with the device were identified, all from the MAUDE database.  Three were from 2017, one from 2018, and one from 2019.  All involved its use in critical care or trauma patients and were related to user error or contraindicated patient selection; none resulted in serious harm to the patient. No adverse events occurred related to its use in the cardiac electrophysiology lab. No case of clinically significant oesophageal injury was reported in a patient who had been protected by the oesophageal temperature control device.

Conclusions

Real world registry data has shown no adverse events reported to date in over 2500 uses of an oesophageal temperature control device in the cardiac electrophysiology lab, for the purpose of active thermal protection. This data supports the randomized trial evidence of its clinical effectiveness. Abstract Figure. Oesophageal active thermal protection

Patient outcomes after AF ablation using Ablation Index technology with oesophageal protection: insight from the IMPACT study

Background

Atrio-oesophageal fistula formation accounts for the majority of AF ablation-related morbidity and mortality. Thermal injury to the oesophagus can be significantly reduced by application of oesophageal cooling for protection during AF ablation. The effect of this method of oesophageal protection in patients receiving radiofrequency (RF) ablation guided by Ablation Index technology is currently unknown.

Objective

To investigate the ability of a temperature control device to protect the oesophagus from ablation-related thermal injury in patients receiving AF ablation guided by Ablation Index technology.

Methods

The IMPACT study is a single-centre, prospective, double-blind randomized controlled trial, which investigated the ability of a controlled method of oesophageal cooling to protect the oesophagus from ablation-related thermal injury. The EnsoETM device was used to deliver oesophageal cooling. This method was compared in a 1:1 randomization to a control group of standard practice utilizing a single-sensor temperature probe. In the study group, the device was used to keep the luminal temperature at 4°C during RF ablation. All participants received AF ablation using Ablation Index technology at posterior and anterior settings (30W at 350–400 and 40W at 450–500, respectively). Endoscopic examination was performed within 7 days post-ablation and oesophageal injury was graded. The patient and the endoscopist were blinded to the randomization. Structured clinical follow up occurred after 3 months post-ablation; both patient and follow up clinician were blinded.

Results

We recruited 188 patients, of whom 120 underwent endoscopic evaluation. Thermal injury to the mucosa was significantly more common in the control group than in those receiving oesophageal protection (12/60 versus 2/60; P=0.008). There was no difference between groups in RF time, lesion duration, force, power and combined ablation index (P value range= 0.2–0.9). Procedure and fluoroscopy duration were similar (P=0.97, P=0.91 respectively). The majority of those who passed through the 1st follow up evaluation (n=136) did not have gastrointestinal or chest pain symptoms post ablation and there was no difference between the randomized groups. Only 4.4% overall had severe symptoms and they were poorly correlated against those who sustained mucosal lesions. AF recurrence was similar in both groups (8% vs 8.8%). There were 2 cases of vascular trauma needing intervention in the control group and 1 case of conservatively managed pericardial effusion in the protected group only. Clinical and endoscopy findings did not report any EnsoETM device-related trauma.

Conclusion

Thermal protection of the oesophagus significantly reduces ablation-related thermal injury compared to standard care when ablation is performed using radiofrequency with Ablation Index technology. This method of oesophageal protection is safe and does not compromise the efficacy of the ablation procedure.

Endoscopy findings and patient symptoms.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): 1. Public hospital: St. George's NHS Foundation Trust; 2. Private company: Attune Medical (Chicago, IL)

Ultrasensitive high-resolution profiling of early seroconversion in patients with COVID-19

Sensitive assays are essential for the accurate identification of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we report a multiplexed assay for the fluorescence-based detection of seroconversion in infected individuals from less than 1 µl of blood, and as early as the day of the first positive nucleic acid test after symptom onset. The assay uses dye-encoded antigen-coated beads to quantify the levels of immunoglobulin G (IgG), IgM and IgA antibodies against four SARS-CoV-2 antigens. A logistic regression model trained using samples collected during the pandemic and samples collected from healthy individuals and patients with respiratory infections before the first outbreak of coronavirus disease 2019 (COVID-19) was 99% accurate in the detection of seroconversion in a blinded validation cohort of samples collected before the pandemic and from patients with COVID-19 five or more days after a positive nasopharyngeal test by PCR with reverse transcription. The high-throughput serological profiling of patients with COVID-19 allows for the interrogation of interactions between antibody isotypes and viral proteins, and should help us to understand the heterogeneity of clinical presentations.

Evaluation of two commercial and two non-commercial immunoassays for the detection of prior infection to SARS-CoV-2

Background Seroepidemiology is an important tool to characterize the epidemiology and immunobiology of SARS-CoV-2 but many immunoassays have not been externally validated raising questions about reliability of study findings. To ensure meaningful data, particularly in a low seroprevalence population, assays need to be rigorously characterized with high specificity. Methods We evaluated two commercial (Roche Diagnostics and Epitope Diagnostics IgM/IgG) and two non-commercial (Simoa and Ragon/MGH IgG) immunoassays against 68 confirmed positive and 232 pre-pandemic negative controls. Sensitivity was stratified by time from symptom onset. The Simoa multiplex assay applied three pre-defined algorithm models to determine sample result. Results The Roche and Ragon/MGH IgG assays each registered 1/232 false positive, the primary Simoa model registered 2/232 false positives, and the Epitope registered 2/230 and 3/230 false positives for the IgG and IgM assays respectively. Sensitivity >21 days post symptom-onset was 100% for all assays except Epitope IgM, but lower and/or with greater variability between assays for samples collected 9-14 days (67-100%) and 15-21 days (69-100%) post-symptom onset. The Simoa and Epitope IgG assays demonstrated excellent sensitivity earlier in the disease course. The Roche and Ragon/MGH IgG assays were less sensitive during early disease, particularly among immunosuppressed individuals. Conclusions The Epitope IgG demonstrated good sensitivity and specificity. The Roche and Ragon/MGH IgG assays registered rare false positives with lower early sensitivity. The Simoa assay primary model had excellent sensitivity and few false positives.

Ultra-Sensitive High-Resolution Profiling of Anti-SARS-CoV-2 Antibodies for Detecting Early Seroconversion in COVID-19 Patients

The COVID-19 pandemic continues to infect millions of people worldwide. In order to curb its spread and reduce morbidity and mortality, it is essential to develop sensitive and quantitative methods that identify infected individuals and enable accurate population-wide screening of both past and present infection. Here we show that Single Molecule Array assays detect seroconversion in COVID-19 patients as soon as one day after symptom onset using less than a microliter of blood. This multiplexed assay format allows us to quantitate IgG, IgM and IgA immunoglobulins against four SARS-CoV-2 targets, thereby interrogating 12 antibody isotype-viral protein interactions to give a high resolution profile of the immune response. Using a cohort of samples collected prior to the outbreak as well as samples collected during the pandemic, we demonstrate a sensitivity of 86% and a specificity of 100% during the first week of infection, and 100% sensitivity and specificity thereafter. This assay should become the gold standard for COVID19 serological profiling and will be a valuable tool for answering important questions about the heterogeneity of clinical presentation seen in the ongoing pandemic.

P3756Diverse activation patterns during persistent atrial fibrillation characterised by dipole density non-contact mapping

Background

Global simultaneous recording of activation during atrial fibrillation (AF) can elucidate underlying mechanisms contributing to AF maintenance. A better understanding of these mechanisms may allow for a personalised ablation strategy to treat persistent AF.

Purpose

To characterise left atrial endocardial activation patterns during AF using a novel non-contact dipole density mapping.

Methods

Activation patterns were characterised into three sub-types: (i) focal with centrifugal activation (FCA); (ii) localised rotational activation (LRA); (iii) localised irregular activation (LIA). Continuous activation patterns were quantified and distributed in the left atrium.

Results

A total of 144 persistent AF segments with 1068 activation patterns from 25 patients were analysed. The most common pattern was LIA (63%), which consist of four disparate features: slow conduction (45%), pivoting (30%), collision (16%) and acceleration (7%). LRA was the second commonest pattern (20%). FCA (17%) arose frequently from the PVs/ostia. Continuous AF activations comprise multiple combinations of FCA, LRA and LIA, transitioning from one to the next without a discernible order. Preferential conduction areas were typically seen in mid-anterior (48%) and lower-posterior (40%) walls where dominant activations were made up of LRA and LIA.

Conclusion

AF is characterised by heterogenous activation patterns that vary between individuals. Clinical implications of individualised ablation strategies guided by dipole density mapping will have to be determined.

Acknowledgement/Funding

None

Professional identity and emerging occupational therapy practice: An autoethnography

BACKGROUND.

Research about occupational therapy practice in the community with people who have been imprisoned remains limited and may be considered an emerging area of practice.

PURPOSE.

This paper provides a critical, first-person account about emerging occupational therapy practice with men transitioning to the community post-imprisonment. The practice context is described and reflected on from the lens of a new graduate.

METHODS.

Autoethnography draws meaning from reciprocal interactions between an individual and a culture. Data was collected by the primary author through reflective journal entries and process notes pertaining to a Photovoice project. Iterative application of established evaluative criteria served as a framework in an analytical writing process.

FINDINGS.

Autethnography promoted self-reflection and professional development while Photovoice provided an evidence-based framework in an emerging setting.

IMPLICATIONS.

Current occupational therapy theories and models have limited applicability to inform practice with marginalized populations potentially benefitting from participatory research (e.g., Photovoice) and autoethnography.

Investigating fetal growth restriction and perinatal risks in appropriate for gestational age infants: using cohort and within-sibling analyses

OBJECTIVE

Fetal growth restriction refers to fetuses that fail to reach their growth potential. Studies within siblings may be useful to disclose fetal growth restriction in appropriate for gestational age (AGA) infants. We analysed associations between birthweight percentiles and perinatal risks in AGA infants, using both population-based and within-sibling analyses.

DESIGN

Population-based cohort study.

SETTING AND SAMPLE

Using nation-wide Swedish registries (1987-2012), we identified 2 134 924 singleton AGA births (10th-90th birthweight percentile for gestational age), of whom 1 377 326 were full siblings.

METHODS

Unconditional Poisson regression was used for population analyses, and conditional (matched) Poisson regression for within-sibling analyses. We estimated associations between birthweight percentiles and stillbirth, neonatal mortality, and morbidity, using incidence rate ratios (IRRs) with 95% confidence intervals (CIs).

RESULTS

Stillbirth and neonatal mortality risks declined with increasing birthweight percentiles, but the declines were larger in within-sibling analyses. Compared with the reference group (40th to <60th percentile), IRRs (95% CIs) of stillbirth for the lowest and highest percentile groups (10th to <25th and 75th-90th percentiles, respectively) were 1.87 (1.72-2.03) to 0.76 (0.68-0.85) in population analysis and 2.60 (2.27-2.98) and 0.43 (0.36-0.50) in within-sibling analysis. Neonatal morbidity risks in term non-malformed infants with low birthweight percentiles were generally only increased in within-sibling analyses.

CONCLUSION

Using birthweight information from siblings may help to define fetal growth restriction in AGA infants.

TWEETABLE ABSTRACT

Size of siblings helps to detect growth-restricted infants with seemingly normal birthweights.

Neonatal intestinal colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae-a 5-year follow-up study

OBJECTIVES

To analyse Klebsiella pneumoniae (KP) isolates from an outbreak of extended-spectrum β-lactamase (ESBL)-producing KP and Escherichia coli (EC) among infants admitted to neonatal intensive care units and to determine the duration of the intestinal colonization.

METHODS

We performed a prospective cohort study of intestinal ESBL-KP/ESBL-EC colonized neonates after a 5-month outbreak in two neonatal intensive care units. Whole genome sequencing, multilocus sequence typing, core genome multilocus sequence typing, pulsed-field electrophoresis and PCR for bla_CTX-M were performed on the first isolates. Stool cultures were performed every second month after discharge until 2 years after discharge and at 5 years of age. The last positive samples were analysed with pulsed-field gel electrophoresis and PCR for bla_CTX-M. The intestinal relative dominance of ESBL-producing Enterobacteriaceae was determined.

RESULTS

Thirteen of 17 patients colonized with ESBL-KP/ESBL-EC survived. Isolates from 16 of 17 patients were available for analysis and featured the same strain type of ESBL-KP: sequence type 101. The strain had capsule type K29 and harboured bla_CTX-M-15. The virulence genes irp1, irp2, iutA, kfu and mrk were detected in all isolates. The median length of colonization was 12.5 months (range, 5-68 months). After 2 years, two of 13 patients were carriers of ESBL-KP and one of 13 of ESBL-EC. At 5 years of age, one neonate was colonized with ESBL-EC. No infant experienced an ESBL-KP/EC-infection during follow-up.

CONCLUSIONS

Two years after discharge, almost one fourth of the study participants were ESBL/KP-EC carriers. ESBL-KP sequence type 101 persisted in two of 13 children for 23 to 26 months. One patient was colonized with ESBL-EC at age 5 years.

Urinary fluoride excretion in preschool children after intake of fluoridated milk and use of fluoride-containing toothpaste

Objective

To assess the urinary fluoride excretion in preschool children after drinking fluoridated milk with 0.185 mg F and 0.375 mg F and to study the impact of use of fluoride toothpaste.

Basic research design

Double-blind cross-over study.

Participants

Nine healthy children, 2.5-4.5 years of age.

Intervention

In a randomized order, participants drank 1.5 dl milk once daily for 7 days with no fluoride added (control), 0.185 mg fluoride added and 0.375 mg fluoride added. The experiment was performed twice with (Part I) and without (Part II) parental tooth brushing with 1,000 ppm fluoride toothpaste. The fluoride content in the piped drinking water was 0.5 mg F/L.

Main outcome measure

Urinary fluoride excretion.

Results

The 24-hour urinary fl uoride excretion/kg body weight varied from 0.014 mg F for the placebo intervention and non-fluoride toothpaste to 0.027 mg F for the 0.375 mg intervention with use of 1,000 ppm fluoride toothpaste. The difference compared with the placebo intervention was not statistically significant for any of the interventions when fluoride toothpaste was used (p⟩0.05) while it was statistically significantly different when non-fluoride toothpaste was used (p⟨0.05).

Conclusions

All sources of fluoride must be considered when designing community programs. With 0.5 mg F/L in the drinking water and daily use of fluoride toothpaste, most children had a fluoride intake optimal for dental health. In this setting, additional intake of fluoride milk was within safe limits up to 0.185 mg/day while conclusions about the safety of 0.375 mg/day were uncertain.

Use of magnesium sulfate before 32 weeks of gestation: a European population-based cohort study

OBJECTIVES

The use of magnesium sulfate (MgSO₄) in European obstetric units is unknown. We aimed to describe reported policies and actual use of MgSO₄ in women delivering before 32 weeks of gestation by indication.

METHODS

We used data from the European Perinatal Intensive Care in Europe (EPICE) population-based cohort study of births before 32 weeks of gestation in 19 regions in 11 European countries. Data were collected from April 2011 to September 2012 from medical records and questionnaires. The study population comprised 720 women with severe pre-eclampsia, eclampsia or HELLP and 3658 without pre-eclampsia delivering from 24 to 31 weeks of gestation in 119 maternity units with 20 or more very preterm deliveries per year.

RESULTS

Among women with severe pre-eclampsia, eclampsia or HELLP, 255 (35.4%) received MgSO₄ before delivery. 41% of units reported use of MgSO₄ whenever possible for pre-eclampsia and administered MgSO₄ more often than units reporting use sometimes. In women without pre-eclampsia, 95 (2.6%) received MgSO₄. 9 units (7.6%) reported using MgSO₄ for fetal neuroprotection whenever possible. In these units, the median rate of MgSO₄ use for deliveries without severe pre-eclampsia, eclampsia and HELLP was 14.3%. Only 1 unit reported using MgSO₄ as a first-line tocolytic. Among women without pre-eclampsia, MgSO₄ use was not higher in women hospitalised before delivery for preterm labour.

CONCLUSIONS

Severe pre-eclampsia, eclampsia or HELLP are not treated with MgSO₄ as frequently as evidence-based medicine recommends. MgSO₄ is seldom used for fetal neuroprotection, and is no longer used for tocolysis. To continuously lower morbidity, greater attention to use of MgSO₄ is needed.

Advanced maternal age increases the risk of very preterm birth, irrespective of parity: a population-based register study

OBJECTIVE

To investigate whether advanced maternal age is associated with preterm birth, irrespective of parity.

DESIGN

Population-based registry study.

SETTING

Swedish Medical Birth Register.

POPULATION

First, second, and third live singleton births to women aged 20 years or older in Sweden, from 1990 to 2011 (n = 2 009 068).

METHODS

Logistic regression analysis was used in each parity group to estimate risks of very and moderately preterm births to women at 20-24, 25-29, 30-34, 35-39, and 40 years or older, using 25-29 years as the reference group. Odds ratios (ORs) were adjusted for year of birth, education, country of birth, smoking, body mass index, and history of preterm birth. Age-related risks of spontaneous and medically indicated preterm births were also investigated.

MAIN OUTCOME MEASURES

Very preterm (22-31 weeks of gestation) and moderately preterm (32-36 weeks) births.

RESULTS

Risks of very preterm birth increased with maternal age, irrespective of parity: adjusted ORs in first, second, and third births ranged from 1.18 to 1.28 at 30-34 years, from 1.59 to 1.70 at 35-39 years, and from 1.97 to 2.40 at ≥40 years. In moderately preterm births, age-related associations were weaker, but were statistically significant from 35-39 years in all parity groups. Advanced maternal age increased the risks of both spontaneous and medically indicated preterm births.

CONCLUSIONS

Advanced maternal age is associated with an increased risk of preterm birth, irrespective of parity, especially very preterm birth. Women aged 35 years and older, expecting their first, second, or third births, should be regarded as a risk group for very preterm birth.

TWEETABLE ABSTRACT

Women aged 35 years and older should be regarded as a risk group for very preterm birth, irrespective of parity.

Lung perfusion scintigraphy prior to lung volume reduction surgery

Purpose: The aim of this study was to evaluate whether lung perfusion scintigraphy (LPS) contributes to the preoperative classification of emphysema heterogeneity in patients undergoing LVRS (lung volume reduction surgery) compared to classification based only on computed tomography (CT).

Material and Methods: Forty-five potential candidates for LVRS were examined with CT and LPS. The distribution of emphysema within the lungs was visually classified into three categories: markedly heterogeneous, intermediately heterogeneous, or homogeneous. The results of the two imaging techniques were compared to an objective, CT-based computerized classification of heterogeneity.

Results: Visual evaluation of all 90 lungs resulted in 50 correct classifications based on CT, in 40 based on LPS and in 68 correct classifications based on the combination of CT and LPS. The combination was superior to CT alone ( p<0.01) in classification of emphysema heterogeneity. There was no significant difference between the evaluations based on either CT or LPS.

Conclusion: The combined information from CT and LPS are superior in assessing emphysema heterogeneity prior to LVRS.

Obese children without comorbidities have impaired microvascular endothelial function

AIM

The aim was to test acetylcholine-induced endothelium-dependent vasodilatation in obese children without comorbidities, compared with normal weight controls, and to analyse associations between vasodilatation and other potential risk factors.

METHODS

Endothelium-dependent vasodilatation was induced by transdermal iontophoresis of acetylcholine in 54 obese children (8.3-18.2 years old, 41% girls) and 44 normal weight controls (7.5-20.2 years old, 82% girls), and the subsequent change in perfusion was measured with laser Doppler flowmetry. In a subgroup of the obese children, associations between acetylcholine-induced vasodilatation and blood lipids, glucose/insulin metabolism, inflammation, 24-h ambulatory blood pressure (ABP), cardiovascular fitness and duration of obesity were evaluated.

RESULTS

We found a lower endothelium-dependent vasodilatory response to acetylcholine in the obese children than the controls (p < 0.001). The peak perfusion response was 33% lower in obese children (p = 0.001). There was a trend towards lower vasodilatation in obese children with higher levels of triglycerides (p = 0.07). Children with the shortest duration of obesity exhibited the lowest vasodilatation (p = 0.03). No associations were found between 24-h ABP, cardiovascular fitness, inflammation and glucose/insulin metabolism.

CONCLUSION

Obese children without comorbidities have significantly impaired microvascular endothelial function. The children who had been obese for a longer time seemed less affected.