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.

POS0382 EXPANSION OF CD4+/CD8+ DOUBLE-POSITIVE T CELLS IS ASSOCIATED WITH A SEVERE DISEASE COURSE IN RHEUMATOID ARTHRITIS

Background:

CD4+/CD8+ double-positive T (dpT) cells are a set of pathologic T cells, representing about 1% of peripheral blood T cells and increasing with age in healthy individuals. Patients with rheumatoid arthritis (RA) more frequently have expanded dpT cells compared to age-matched controls, up to a frequency of 8% [1]. However, whether dpT cell expansion harbors clinical significance in RA is not known.

Objectives:

The goal of the study was to assess possible associations of DPT expansion with clinical features of patients with RA.

Methods:

In this cross-sectional study, dpT cells were measured in RA patients (n=70) via fluorescence-activated flow cytometry. Clinical data including age, sex, disease duration, treatment history, disease activity parameters, and radiographic structural damage was collected. Radiographs of hands and feet were used to determine the modified Sharp/van der Heijde (SvdH) score. Expansion of dpT cells was defined as a frequency of >2% of the total T cell pool, based on reference ranges determined in a large cohort of healthy individuals [2]. Mann-Whitney-U test was used to compare groups and X2 test was used for contingency tables. Statistical analyses were conducted using GraphPad Prism v8 (GraphPad Software, San Diego, USA).

Results:

DpT cells were expanded in more than a quarter of our cohort (n=19, 27.1%). Patients with expanded dpT cells more often used biologics or targeted synthetic DMARDs than patients with low dpT cells (68.4% vs. 38%, p=0.02). Radiographic damage was also significantly worse in patients with DPT expansion, as shown in their higher SvdH score (median 24.5 vs. 6, p=0.008) and its component scores for erosion (median 19 vs. 0, p=0.004) and joint space narrowing (median 8 vs. 2, p=0.017) (figure 1A). There was no difference regarding sex, age, disease duration, seropositivity and disease activity between the groups (figure 1B).

Conclusion:

DpT cell expansion is associated with higher scores of radiographic structural damage despite more frequent use of highly effective therapeutics. An expansion of dpT cells is not uncommon in RA, and affected patients represent a subset at high risk for a more severe disease course.

References:

[1]Quandt D, Rothe K, Scholz R, et al. Peripheral CD4CD8 Double Positive T Cells with a Distinct Helper Cytokine Profile Are Increased in Rheumatoid Arthritis. PLoS ONE 2014;9:e93293. doi:10.1371/journal.pone.0093293

[2]Apoil PA, Puissant-Lubrano B, Congy-Jolivet N, et al. Reference values for T, B and NK human lymphocyte subpopulations in adults. Data Brief 2017;12:400–4. doi:10.1016/j.dib.2017.04.019

Figure 1.

DpT cell expansion is associated with radiographic progression. SvdH, modified Sharp/van der Heijde Score; DpT, CD4+/CD8+ double-positive T cells.

Disclosure of Interests:

None declared

Excess Soluble fms-like Tyrosine Kinase 1 Correlates With Endothelial Dysfunction and Organ Failure in Critically Ill Coronavirus Disease 2019 Patients

Excess soluble fms-like tyrosine kinase 1 (sFlt-1), a soluble inhibitor of vascular endothelial growth factor pathway, has been demonstrated to promote endothelial dysfunction. Here, we demonstrate that sFlt-1 plasma levels correlate with respiratory symptom severity, expression of endothelial dysfunction biomarker, and incidence of organ failure in coronavirus disease 2019 patients. Clinical Trials Registration: NCT04394195.

Pathophysiology and Imaging Findings of COVID-19 Infection: An Organ-system Based Review

BACKGROUND

COVID-19 commonly presents with upper respiratory symptoms; however, studies have shown that SARS-CoV-2 infection affects multiple organ systems. Here, we review the pathophysiology and imaging characteristics of SARS-CoV-2 infection in organ systems throughout the body and explore commonalities.

OBJECTIVE

Familiarity with the underlying pathophysiology and imaging characteristics is essential for the radiologist to recognize these findings in patients with COVID-19 infection. Though pulmonary findings are the most prevalent presentation, COVID-19 may have multiple manifestations and recognition of the extrapulmonary manifestations is especially important because of the potential serious and long-term effects of COVID-19 on multiple organ systems.

Point absorbers in Advanced LIGO

Small, highly absorbing points are randomly present on the surfaces of the main interferometer optics in Advanced LIGO. The resulting nanometer scale thermo-elastic deformations and substrate lenses from these micron-scale absorbers significantly reduce the sensitivity of the interferometer directly though a reduction in the power-recycling gain and indirect interactions with the feedback control system. We review the expected surface deformation from point absorbers and provide a pedagogical description of the impact on power buildup in second generation gravitational wave detectors (dual-recycled Fabry-Perot Michelson interferometers). This analysis predicts that the power-dependent reduction in interferometer performance will significantly degrade maximum stored power by up to 50% and, hence, limit GW sensitivity, but it suggests system wide corrections that can be implemented in current and future GW detectors. This is particularly pressing given that future GW detectors call for an order of magnitude more stored power than currently used in Advanced LIGO in Observing Run 3. We briefly review strategies to mitigate the effects of point absorbers in current and future GW wave detectors to maximize the success of these enterprises.

Functional Flow Cytometric Assay for Reliable and Convenient Heparin-Induced Thrombocytopenia Diagnosis in Daily Practice

Reliable laboratory diagnosis of heparin-induced thrombocytopenia (HIT) remains a major clinical concern. Immunoassays are highly sensitive, while confirmatory functional tests (based on heparin-dependent platelet activation) lack standardization. We evaluated the diagnostic performance of a functional flow cytometric assay (FCA) based on the detection of heparin-dependent platelet activation with an anti-p-selectin. A total of 288 patients were included (131 HIT-positive and 157 HIT-negative) with a HIT diagnosis established by expert opinion adjudication (EOA) considering clinical data and local laboratory results. The FCA was centrally performed in a single laboratory on platelet-rich plasma, using a very simple four-color fluorometer. The results were standardized according to the Heparin Platelet Activation (HEPLA) index. The serotonin release assay (SRA) was performed in the four French reference laboratories. Based on the final HIT diagnosis established by EOA, the sensitivity and specificity of the FCA were 88 and 95%, respectively, values very similar to those of the SRA (88 and 97%, respectively). This study showed that the FCA, based on easily implementable technology, may be routinely used as a reliable confirmatory test for HIT diagnosis.

AgeR deletion decreases soluble fms-like tyrosine kinase 1 production and improves post-ischemic angiogenesis in uremic mice

Peripheral arterial disease occurs more frequently and has a worse prognosis in patients with chronic kidney disease (CKD). The receptor for advanced glycation end products (RAGE) is involved in multiple aspects of uremia-associated vasculopathy. Previous data suggest that the RAGE pathway may promote soluble fms-like tyrosine kinase 1 (sFlt1) production, an anti-angiogenic molecule. Thus, we tested the hypothesis that the deletion of AgeR would decrease sFlt1 production and improve post-ischemic revascularization in uremic condition. We used a well-established CKD model (5/6 nephrectomy) in WT and AgeR-/- C57/Bl6 mice. Hindlimb ischemia was induced by femoral artery ligation. Revascularization was evaluated by complementary approaches: ischemic limb retraction, LASCA imagery, and capillary density. The production of sFlt1 was assessed at both RNA and protein levels. After hindlimb ischemia, uremic mice showed slower functional recovery (p < 0.01), decreased reperfusion (p < 0.01), lower capillary density (p = 0.02), and increased circulating sFlt1 levels (p = 0.03). AgeR deletion restored post-ischemic angiogenesis and was protective from sFlt1 increase in uremic mice. These findings show the main role of RAGE in post-ischemic angiogenesis impairment associated with CKD. RAGE may represent a key target for building new therapeutic approaches to improve the outcome of CKD patients with PAD.

Comparison of standard versus ultrasound guidance in radial and femoral access: a subanalysis of the randomised SURF trial

Background

Ultrasound (US) guidance in facilitating arterial access may reduce vascular complications and possible bleeding. There are still limited trials assessing real-time US guidance for coronary angiography. The SURF (Standard versus ultrasound-guided radial and femoral access in coronary angiography and intervention) trial showed no difference in primary outcome when the combined radial and femoral ultrasound analysis compared with standard (SD) technique, but significantly improved access efficiency and success rate.

Purpose

This subanalysis compared clinical and procedural outcomes of the individual radial and femoral access with US guidance versus standard technique.

Methods

Patients (n=1388) undergoing coronary angiography and percutaneous coronary intervention were randomised (1:1) into radial or femoral access, and (1:1) to SD or US guidance. The primary outcome was a composite of ACUITY (Acute Catheterisation and Urgent Intervention Triage strategY) major bleeding, MACE (death, stroke, myocardial infarction or urgent target lesion revascularisation) and vascular complications at 30 days. Secondary outcomes were access time, number of attempts, venepuncture, difficult accesses and first-pass success.

Results

Compared to standard, US guidance produced no difference in composite endpoint for both radial (1.4% vs 1.2%, p=0.78) and femoral (3.1% vs 3.8%, p=0.65) accesses. ACUITY major bleeding (radial: 0.9% US vs 0.6% SD, p=0.69; femoral: 1.9% US vs 2.3% SD, p=0.69), vascular complications (radial: 0.3% US vs 0.3% SD, p=0.98; femoral: 1.3% US vs 0.9% SD, p=0.63) and MACE (radial: 0.6% US vs 0.3% SD, p=0.59; femoral: 0.9% US vs 1.2% SD, p=0.78) were similar in the US and SD approaches, respectively. However, US guidance resulted in improved procedural outcomes for both accesses. Femoral access derived the most benefit from US, with reduced mean access time (73 sec vs 97 sec, p=0.006), attempts (1.35 vs 1.84, p≤0.0001), difficult accesses (1.8% vs 6.2%, p=0.004), venepuncture (5.8% vs 12.6%, p=0.002) and improved first-pass success (77.2% vs 58.8%, p≤0.0001). For radial, US reduced attempts (1.59 vs 1.97, p=0.0007), difficult accesses (6.9% vs 12.3%, p=0.02), venepuncture (2.5% vs 5.6%, p=0.04) and improved first-pass success (69.2% vs 60.7%, p=0.02). There was no difference in radial mean access time (111 sec vs 126 sec, p=0.18).

Conclusions

US guidance in radial and femoral access did not reduce primary outcome compared to standard technique. The use of US significantly improved the efficiency and success rate of arterial cannulation, with femoral access derived the most benefit.

Funding Acknowledgement

Type of funding source: None

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}.

Receptor for Advanced Glycation End Products is Involved in Platelet Hyperactivation and Arterial Thrombosis during Chronic Kidney Disease

BACKGROUND

 Chronic kidney disease (CKD) is associated with a high cardiovascular mortality due to increased rates of vascular lesions and thrombotic events, as well as serum accumulation of uremic toxins. A subgroup of these toxins (advanced glycation end products [AGEs] and S100 proteins) can interact with the receptor for AGEs (RAGE). In this study, we analyzed the impact of CKD on platelet function and arterial thrombosis, and the potential role of RAGE in this process.

METHODS

 Twelve weeks after induction of CKD in mice, platelet function and time to complete carotid artery occlusion were analyzed in four groups of animals (sham-operated, CKD, apolipoprotein E [Apoe]^-/-, and Apoe^-/-/Ager^-/- mice).

RESULTS

 Analysis of platelet function from whole blood and platelet-rich plasma showed hyperactivation of platelets only in CKD Apoe^-/- mice. There was no difference when experiments were done on washed platelets. However, preincubation of such platelets with AGEs or S100 proteins induced RAGE-mediated platelet hyperactivation. In vivo, CKD significantly reduced carotid occlusion times of Apoe^-/- mice (9.2 ± 1.1 vs. 11.1 ± 0.6 minutes for sham, p < 0.01). In contrast, CKD had no effect on occlusion times in Apoe^-/-/Ager^-/- mice. Moreover, carotid occlusion in Apoe^-/- CKD mice occurred significantly faster than in Apoe^-/-/Ager^-/- CKD mice (p < 0.0001).

CONCLUSION

 Our results show that CKD induces platelet hyperactivation, accelerates thrombus formation in a murine model of arterial thrombosis, and that RAGE deletion has a protective role. We propose that RAGE ligands binding to RAGE is involved in CKD-induced arterial thrombosis.

Prevention of thrombotic risk in hospitalized patients with COVID-19 and hemostasis monitoring

COVID-19 is an infection induced by the SARS-CoV-2 coronavirus, and severe forms can lead to acute respiratory distress syndrome (ARDS) requiring intensive care unit (ICU) management. Severe forms are associated with coagulation changes, mainly characterized by an increase in D-dimer and fibrinogen levels, with a higher risk of thrombosis, particularly pulmonary embolism. The impact of obesity in severe COVID-19 has also been highlighted.In this context, standard doses of low molecular weight heparin (LMWH) may be inadequate in ICU patients, with obesity, major inflammation, and hypercoagulability. We therefore urgently developed proposals on the prevention of thromboembolism and monitoring of hemostasis in hospitalized patients with COVID-19.Four levels of thromboembolic risk were defined according to the severity of COVID-19 reflected by oxygen requirement and treatment, the body mass index, and other risk factors. Monitoring of hemostasis (including fibrinogen and D-dimer levels) every 48 h is proposed. Standard doses of LMWH (e.g., enoxaparin 4000 IU/24 h SC) are proposed in case of intermediate thrombotic risk (BMI < 30 kg/m2, no other risk factors and no ARDS). In all obese patients (high thrombotic risk), adjusted prophylaxis with intermediate doses of LMWH (e.g., enoxaparin 4000 IU/12 h SC or 6000 IU/12 h SC if weight > 120 kg), or unfractionated heparin (UFH) if renal insufficiency (200 IU/kg/24 h, IV), is proposed. The thrombotic risk was defined as very high in obese patients with ARDS and added risk factors for thromboembolism, and also in case of extracorporeal membrane oxygenation (ECMO), unexplained catheter thrombosis, dialysis filter thrombosis, or marked inflammatory syndrome and/or hypercoagulability (e.g., fibrinogen > 8 g/l and/or D-dimers > 3 μg/ml). In ICU patients, it is sometimes difficult to confirm a diagnosis of thrombosis, and curative anticoagulant treatment may also be discussed on a probabilistic basis. In all these situations, therapeutic doses of LMWH, or UFH in case of renal insufficiency with monitoring of anti-Xa activity, are proposed.In conclusion, intensification of heparin treatment should be considered in the context of COVID-19 on the basis of clinical and biological criteria of severity, especially in severely ill ventilated patients, for whom the diagnosis of pulmonary embolism cannot be easily confirmed.

Efficacy and follow-up of anti-VEGF injections in diabetic macular edema in real-life practice at the Dijon university medical centre through the Save Sight Registries

PURPOSE

To evaluate the efficacy of intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections (IVT) in diabetic macular edema (DME) in real-life practice using the Save Sight Registries (SSR).

MATERIAL AND METHODS

We conducted an observational, single-centre, retrospective study in the department of ophthalmology of the Dijon University Hospital. We included treatment-naive patients who presented with DME between January 2016 and December 2017. Demographic and clinical data, follow-up visits, and treatments administered were entered into the SSR, an international online ophthalmic registry. Primary endpoints were the change in best-corrected visual acuity (BCVA) and central subfield thickness (CST) from baseline to 12 and 24 months.

RESULTS

Fifty-eight eyes of 43 patients with a mean [standard deviation (SD)] age of 67.1 [9.5] years were included. Forty-one eyes completed 12 months of follow-up, and 17 eyes completed 24 months of follow up. Median [SD] baseline BCVA was 56.1 [22.9] ETDRS letters and the median [95% confidence interval (95% CI)] baseline CST was 447.9 [161.0] micrometers (μm). Median [95% CI] improvement in BCVA from baseline to months 12 and 24 were respectively, +5.6 [+0.5; +10.7] ETDRS letters and +7.7 [-2.8; +18.2] ETDRS letters. The median [95% CI] decrease in CST from baseline to months 12 and 24 were respectively, -110.9 [-154.5; -67.3] μm and -125.5 [-198.0; -53.0] μm.

CONCLUSION

Our clinical practice can be evaluated easily with the SSR system. In real life, anti-VEGF IVT are an effective treatment for DME, which result in improved BCVA and decreased CST.

Ticagrelor Prevents Endothelial Cell Apoptosis through the Adenosine Signalling Pathway in the Early Stages of Hypoxia

BACKGROUND

Several studies have reported the beneficial effects of anti-platelet drugs in cardioprotection against ischaemia-reperfusion injuries. To date, no studies have focused on the indirect cytoprotective effects of ticagrelor via adenosine receptor on the endothelium.

METHOD

By evaluating cell viability and cleaved caspase 3 expression, we validated a model of endothelial cell apoptosis induced by hypoxia. In hypoxic endothelial cells treated with ticagrelor, we quantified the extracellular concentration of adenosine, and then we studied the involvement of adenosine pathways in the cytoprotective effect of ticagrelor.

RESULTS

Our results showed that 10 µM ticagrelor induced an anti-apoptotic effect in our model associated with an increase of extracellular adenosine concentration. Similar experiments were conducted with cangrelor but did not demonstrate an anti-apoptotic effect. We also found that A2B and A3 adenosine receptors were involved in the anti-apoptotic effect of ticagrelor in endothelial cells exposed to 2 h of hypoxia stress.

CONCLUSION

we described an endothelial cytoprotective mechanism of ticagrelor against hypoxia stress, independent of blood elements. We highlighted a mechanism triggered mainly by the increased extracellular bioavailability of adenosine, which activates A2B and A3 receptors on the endothelium.

Effectiveness, retention, and safety of modified ketogenic diet in adults with epilepsy at a tertiary-care centre in the UK

With the rising demand for ketogenic diet therapy in adult epilepsy, there is a need for research describing the real-life effectiveness, retention, and safety of relevant services. In this 1-year prospective cohort study we present outcomes of the first 100 referrals for modified ketogenic diet (MKD) at the UK's largest tertiary-care epilepsy centre, where patients received dietetic review up to twice per week. Of the first 100 referrals, 42 (31 females, 11 males; mean age 36.8 [SD ± 11.4 years]) commenced MKD, having used a mean of 4 (SD ± 3) previous antiepileptic drugs. Retention rates were: 60% at 3 months, 43% at 6 months, and 29% at 12 months. 60% of patients reported an improvement in seizure frequency, 38% reported a > 50% reduction, and 13% reported a period of seizure freedom; 30% reported a worsening in seizure frequency at some point during MKD therapy. The most common reasons for discontinuing MKD were side effects and diet restrictiveness. The most common side effects were weight loss, gastrointestinal symptoms and low mood. The likelihood of discontinuing MKD was significantly decreased by experiencing an improvement in seizure frequency (p ≤ 0.001). This study demonstrates that MKD can be effective in adults, although, even with regular dietetic support, retention rates remain low, and periods of worsening seizure frequency are common.

Relative Effectiveness of Selenite Cystine Broth, Tetrathionate Broth, and Rappaport-Vassiliadis Medium for Recovery of Salmonella spp. from Raw Flesh, Highly Contaminated Foods, and Poultry Feed: Collaborative Study

A collaborative study was performed in 18 laboratories to validate use of Rappaport-Vassiliadis (RV) medium in the standard culture method for recovery of Salmonella spp. from raw, highly contaminated foods and poultry feed. RV medium made from its individual ingredients and incubated at 42�C was compared with selenite cystine (SC) broth incubated at 35�C and tetrathionate (TT) broth incubated at 35� and 43�C for effectiveness in recovery of Salmonella spp. Four artificially contaminated foods (oysters, frog legs, mushrooms, and shrimp) and poultry feed and one naturally contaminated food (chicken) were analyzed. The artificially contaminated foods were inoculated with single serovars of Salmonella at target levels of 0.04 colony-forming units (CFU)/g for the low level and 0.4 CFU/g for the high level. For analysis of 1125 test portions, RV medium (42�C) recovered Salmonellairom 409 test portions; TT (43�C), from 368 test portions; TT (35�C), from 310 test portions; and SC (35�C), from 334 test portions. Overall, RV medium was comparable with or better than other selective enrichments for recovery of Salmonella from the foods in this study, except mushrooms. From mushrooms, SC broth (35�C) recovered more positive test portions than did RV medium (42�C) and TT broth (43�C). The method for detection of Salmonella in raw, highly contaminated foods and