Towards a spatially resolved, single-ended TDLAS system for characterizing the distribution of gaseous species

Many applications require diagnostics that can quantify the distribution of chemical gas species and gas temperature along a single line-of-sight, which is challenging in process environments with limited optical access. To this end, we present an approach that combines time-of-flight Light Detection and Ranging (LiDAR) with Tunable Diode Laser Absorption Spectroscopy (TDLAS) to scan individual gas molecular transition lines. This method is applicable in situations where scattering objects are distributed along the beam path, such as solid fuel combustion, or when dealing with multiple gas volumes separated by weakly reflecting windows. The approach is demonstrated through simulation studies and an initial experimental proof of concept for separated gas volumes.

Empagliflozin inhibits increased Na influx in atrial cardiomyocytes of patients with HFpEF

AIMS

Heart failure with preserved ejection fraction (HFpEF) causes substantial morbidity and mortality. Importantly, atrial remodeling and atrial fibrillation is frequently observed in HFpEF. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have recently been shown to improve clinical outcomes in HFpEF, and post-hoc analyses suggest atrial antiarrhythmic effects. We tested if isolated human atrial cardiomyocytes from patients with HFpEF exhibit an increased Na influx, which is known to cause atrial arrhythmias, and if that is responsive to treatment with the SGTL2i empagliflozin.

METHODS AND RESULTS

Cardiomyocytes were isolated from atrial biopsies of 124 patients (82 with HFpEF) undergoing elective cardiac surgery. Na influx was measured with the Na-dye Asante Natrium Green-2 AM (ANG-2). Compared to patients without heart failure (NF), Na influx was doubled in HFpEF patients (NF vs HFpEF: 0.21±0.02 vs 0.38±0.04 mmol/L/min (N=7 vs 18); p=0.0078). Moreover, late INa (measured via whole-cell patch clamp) was significantly increased in HFpEF compared to NF. Western blot and HDAC4 pulldown assay indicated a significant increase in CaMKII expression, CaMKII autophosphorylation, CaMKII activity, and CaMKII-dependent NaV1.5 phosphorylation in HFpEF compared to NF, whereas NaV1.5 protein and mRNA abundance remained unchanged. Consistently, increased Na influx was significantly reduced by treatment with the CaMKII inhibitor autocamtide-2 related inhibitory peptide (AIP), late INa inhibitor tetrodotoxin (TTX) but also with NHE1 inhibitor cariporide. Importantly, empagliflozin abolished both increased Na influx and late INa in HFpEF. Multivariate linear regression analysis, adjusting for important clinical confounders, revealed HFpEF to be an independent predictor for changes in Na handling in atrial cardiomyocytes.

CONCLUSION

We show for the first time increased Na influx in human atrial cardiomyocytes from HFpEF patients, partly due to increased late INa and enhanced NHE1-mediated Na influx. Empagliflozin inhibits Na influx and late INa, which could contribute to antiarrhythmic effects in patients with HFpEF.

On the lattice ground state of densely packed hard ellipses

Among lattice configurations of densely packed hard ellipses, Monte Carlo simulations are used to identify the so-called parallel and diagonal lattices as the two favorable states. The free energies of these two states are computed for several system sizes employing the Einstein crystal method. An accurate calculation of the free energy difference between the two states reveals the parallel lattice as the state with the lowest free energy. The origin of the entropic difference between the two states is further elucidated by assessing the roles of the translational and rotational degrees of freedom.

First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γp→pπ^{0} and γp→nπ^{+}

We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g., G) and circularly polarized photons (e.g., E) and a longitudinally polarized target. The new data cover a photon energy range 270-1400 MeV for the pπ^{0} final state (230-842 MeV for the nπ^{+} final state) and the full range of pion polar angles, θ, providing the most precise measurement of the observable E. A moment analysis gives a clear observation of the pη cusp in the pπ^{0} final state.

An iterative approach to the development of a sole ulcer induction model in Holstein cows

Our objective was to develop a sole ulcer (SU) induction model that can be used to investigate new and more efficacious methods for the treatment and prevention of SU. Three iterations [phase (P)1, P2, and P3] of an SU induction model designed to mimic mechanical and presumed metabolic pathways for SU development were conducted. The results from P1 and P2 identified alterations for the subsequent phase. Each phase used cows with similar calving dates that were randomly assigned (n = 4) to treatments. Control cows (P1CON, P3CON) did not undergo any challenges to induce SU development. Treatment cows were challenged with a hoof block (B) applied to the right hind lateral hoof. Other treatments included restricted lying time (L), restricted feed intake (F), or systemic lipopolysaccharide (LPS) administration. Treatment comparisons were P1CON versus P1BL, P2B versus P2BL, and P3CON versus P3BLF and P3BLF+LPS for P1, P2, and P3, respectively. Pregnant nulliparous Holstein cows were used in P1 and P3, and the P1 cohort was used in P2 during mid-lactation [125.9 ± 7.20 d in milk (DIM)]. Challenges were applied during a set challenge period (P1: -14 to 14 DIM, P2: 126-168 DIM, P3: -14 to 28 DIM). The P1BL cows had a hoof block applied and lying time restricted for 5 h/d. The P2B and P2BL cows had a hoof block and P2BL cows also had their lying time restricted for 18 h/d for 2 d/wk. The P3BLF and P3BLF+LPS cows had a hoof block, 6 h/d of lying time restricted 2 d/wk, and had their DMI restricted by 30% for 2 d/wk. At weekly intervals during wk 1 to 3 postpartum, P3BLF+LPS cows received jugular administration of 0.031, 0.062, and 0.125 µg of LPS per kg of body weight, respectively. Primary response measurements included hoof lesion and locomotion scoring, lying time, hoof thermography, and weight distribution per hoof. No SU induction occurred but sole hemorrhages, a precursor to SU, occurred during the postchallenge period of all phases. Temperature of the blocked hoof at the end of the challenge period did not change for P3CON cows but increased by 5.5°C and 6.2°C for P3BLF and P3BLF+LPS, respectively. Notable increases in lameness and lack of weight-bearing on the blocked hind hoof occurred for challenge treatment cows during the challenge period of P2 and P3. These changes did not persist after the hoof blocks were removed, indicating that hoof blocks succeeded in altering cow gait mechanics, but not enough to induce long-term lameness or SU. Lying restriction challenged cows in P2 and P3, indicated by a compensatory increase in lying time on the day following lying restriction compared with that on the day before restriction. In P3, lying time had the greatest depression during restriction and compensation following restriction in P3BLF+LPS cows, with LPS challenges potentially increasing the other challenge's effects. Future iterations of the SU induction model should include hoof block use, evaluate longer and more frequent standing and inclusion of forced walking bouts, and include DMI and LPS metabolic challenges.

XACML for Mobility (XACML4M)-An Access Control Framework for Connected Vehicles

The automotive industry is experiencing a transformation with the rapid integration of software-based systems inside vehicles, which are complex systems with multiple sensors. The use of vehicle sensor data has enabled vehicles to communicate with other entities in the connected vehicle ecosystem, such as the cloud, road infrastructure, other vehicles, pedestrians, and smart grids, using either cellular or wireless networks. This vehicle data are distributed, private, and vulnerable, which can compromise the safety and security of vehicles and their passengers. It is therefore necessary to design an access control mechanism around the vehicle data's unique attributes and distributed nature. Since connected vehicles operate in a highly dynamic environment, it is important to consider context information such as location, time, and frequency when designing a fine-grained access control mechanism. This leads to our research question: How can Attribute-Based Access Control (ABAC) fulfill connected vehicle requirements of Signal Access Control (SAC), Time-Based Access Control (TBAC), Location-Based Access Control (LBAC), and Frequency-Based Access Control (FBAC)? To address the issue, we propose a data flow model based on Attribute-Based Access Control (ABAC) called eXtensible Access Control Markup Language for Mobility (XACML4M). XACML4M adds additional components to the standard eXtensible Access Control Markup Language (XACML) to satisfy the identified requirements of SAC, TBAC, LBAC, and FBAC in connected vehicles. Specifically, these are: Vehicle Data Environment (VDE) integrated with Policy Enforcement Point (PEP), Time Extensions, GeoLocation Provider, Polling Frequency Provider, and Access Log Service. We implement a prototype based on these four requirements on a Raspberry Pi 4 and present a proof-of-concept for a real-world use case. We then perform a functional evaluation based on the authorization policies to validate the XACML4M data flow model. Finally, we conclude that our proposed XACML4M data flow model can fulfill all four of our identified requirements for connected vehicles.

[Distortion of the cervical spine : Pathophysiology, diagnostics, treatment and assessment]

Distortion or whiplash trauma of the cervical spine is an injury pattern associated with motor vehicle collisions and typically occurs after rear impact collisions, but is not limited to this type of collision and accident. The vast majority of these injuries are low-grade injuries according to the Quebec Task Force (QTF) classification, whereby no objective morphological correlates can be determined in clinical and radiological examinations. The prognosis is predominantly favorable and the condition is self-limiting; however, care must be taken with respect to complex courses with chronic pain and the manifestation of neuropsychiatric complaints. Due to the mechanism of the accident this injury pattern is particularly frequent in accidents associated with third party liability insurance claims. The discrepancy between subjective complaints and the presence of objective findings is a particular challenge for the assessment by the medical expert.

Empagliflozin inhibits increased Na influx in HFpEF cardiomyocytes and reduces arrhythmic activity in human atrial trabeculae

Background

Heart failure with preserved ejection fraction (HFpEF) is a major health problem associated with substantial morbidity and mortality. However, the underlying pathophysiological mechanisms are poorly understood, and effective treatment strategies are scarce. Importantly, SGLT2i, which have been suggested to improve cellular Na and Ca homeostasis in HFrEF, have recently been shown to also improve clinical outcomes in patients with HFpEF. Interestingly, post-hoc analyses of clinical data suggest an involvement of anti-arrhythmic effects of SGLT2i.

Purpose

We tested, if isolated human atrial cardiomyocytes from patients with HFpEF exhibit an increased Na influx that is responsive to treatment with the SGLT2i empagliflozin (Empa) and if Empa has anti-arrhythmic properties in human atrial trabeculae.

Methods

Atrial biopsies were obtained from 101 patients undergoing elective cardiac surgery. Na influx was measured as increase in [Na]i during Na/K-ATPase inhibition in isolated cardiomyocytes loaded with the Na-sensitive fluorescence dye Asante Natrium Green–2 AM (ANG-2). Western Blot and HDAC4 pulldown assay were used to investigate NaV1.5 expression/phosphorylation as well as CaMKII expression/autophosphorylation and activity. Anti-arrhythmic effects of Empa were evaluated as the reduction in premature atrial complexes (PACs), which were induced in electrically field-stimulated (1Hz) human atrial trabeculae by superfusion with isoproterenol (100 nM) and high Ca (3.5 mM).

Results

Compared to patients without heart failure (NF), Na influx was almost doubled in HFpEF patients (NF vs HFpEF: 0.21±0.02 vs 0.38±0.04 mmol/L/min (N=7 vs 18); p=0.005) (Fig. 1D, E). CaMKII expression, CaMKII autophosphorylation, CaMKII activity, and CaMKII-dependent NaV1.5 phosphorylation were significantly increased in atrial biopsies of HFpEF patients, whereas NaV1.5 protein abundance remained unchanged (Fig. 1A–C). Consistent with these results, the increased Na influx was significantly reduced by treatment with the specific CaMKII inhibitor autocamtide-2 related inhibitory peptide (AIP) and the late INa inhibitor tetrodotoxin (TTX) (Fig. 1D, E). Importantly, Empa also abolished the increased Na influx in HFpEF cardiomyocytes (Fig. 1D, E). Multivariate linear regression analysis, adjusting for clinical co-variates, revealed HFpEF to be an independent predictor of cardiomyocyte Na handling. In line with Empa-mediated inhibition of Na influx, the frequency of PACs in human atrial trabeculae was significantly reduced by Empa (Fig. 1F, G).

Conclusion

This is the first study to demonstrate increased Na influx in human cardiomyocytes from HFpEF patients potentially by an increased CaMKII-dependent NaV1.5 phosphorylation. Excitingly, treatment with Empa decreases this Na influx in HFpEF cardiomyocytes and reduces isoproterenol-induced arrhythmic activity in human atrial trabeculae, which could contribute to the cardioprotective effects of this drug in patients with HFpEF.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Else Kröner-Fresenius-Stiftung,Deutsche Forschungsgemeinschaft

Oxidative activation of CaMKII mediates arrhythmias and contractile dysfunction in an obstructive sleep apnea mouse model

Background/Introduction

Atrial arrhythmias frequently occur in patients with obstructive sleep apnea (OSA), but the underlying mechanisms remain insufficiently understood. We recently demonstrated that CaMKII-dependent pro-arrhythmic activity is increased in patients with OSA, but the mechanisms of CaMKII activation remain unknown. Interestingly, OSA can lead to increased reactive oxygen species production, which may facilitate CaMKII activation by oxidation at methionine residues 281/282.

Purpose

We tested if oxidation of CaMKII is involved in the development of arrhythmias and contractile dysfunction in vitro and in vivo in a mouse model of obstructive sleep apnea by tongue enlargement.

Methods

Experiments were performed using 41 wild-type (WT) and 25 genetically modified mice lacking oxidative CaMKII activation due to mutation of methionine 281/282 to valine (MMVV mice). Polytetrafluorethylene (PTFE, 100 μl) was injected into the tongue of 23 WT and 12 MMVV mice to induce OSA by sustained tongue enlargement as previously established. Whole body plethysmography was performed to confirm success of intervention. Echocardiography was performed at baseline and after 8 weeks to assess left-ventricular function. After 8 weeks, isolated atrial and ventricular cardiomyocytes were incubated with the Ca-sensitive dye FURA-2 AM (5 μM, 15 min) and analyzed with epifluorescence microscopy under regular electrical field stimulation (1 Hz).

Results

PTFE injection resulted in an increased frequency of inspiratory flow limitations (IFLs/h) from 27.4±5.95 to 59.6±6.22 in PTFE mice (p<0.001, fig. 1A). Interestingly, in WT PTFE mice, left ventricular ejection fraction (LVEF, in %) was reduced at 8 weeks post procedure from 57.0±1.36 to 51.5±1.85 (p=0.001, fig. 1B). Importantly, mice lacking oxidative CaMKII activation were protected from such decline in contractile function, and LVEF was higher at 8 weeks vs. WT PTFE (p<0.001, fig. 1B). Congruent with deterioration of contractility in vivo, the Ca transient amplitude after 30s pause (normalized to steady-state before pause) was decreased in ventricular cardiomyocytes of WT PTFE mice indicating increased SR Ca leak (p for interaction genotype x PTFE = 0.014, fig. 1C). In contrast to WT, the post-pause ratio was increased in MMVV PTFE mice (p=0.018, fig. 1C). In addition to contractile function, cellular arrhythmic events were analyzed as non-stimulated pro-arrhythmic events (NSEs) during steady-state electrical field stimulation at 1 Hz (fig. 1D, red arrows). NSE frequency was increased in atrial cardiomyocytes from WT PTFE mice with 0.050±0.005 compared to 0.018±0.003 s–1 in WT CTRL (p<0.001, fig. 1D). Intriguingly, MMVV mice were protected from NSEs after PTFE treatment (0.020±0.004, p<0.001 vs. WT PTFE, Fig. 1D).

Conclusion

In a mouse model of obstructive sleep apnea, contractile dysfunction and pro-arrhythmic activity are modulated by oxidative CaMKII activation, which may have therapeutic implications.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft; Medical Faculty at University of Regensburg

Measurement of Compton Scattering at MAMI for the Extraction of the Electric and Magnetic Polarizabilities of the Proton

A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the Mainz Microtron. The incident photons were produced by the recently upgraded Glasgow-Mainz photon tagging facility and impinged on a cryogenic liquid hydrogen target, with the scattered photons detected in the Crystal Ball/TAPS setup. Using the highest statistics Compton scattering data ever measured on the proton along with two effective field theories (both covariant baryon and heavy-baryon) and one fixed-t dispersion relation model, constraining the fits with the Baldin sum rule, we have obtained the proton electric and magnetic polarizabilities with unprecedented precision: α_{E1}=10.99±0.16±0.47±0.17±0.34, β_{M1}=3.14±0.21±0.24±0.20±0.35; in units of 10^{-4}  fm^{3} where the errors are statistical, systematic, spin polarizability dependent, and model dependent.

Incorporating 3D reconstruction in preoperative surgical planning of Multiple Myomectomy

Background

Medical 3D imaging is a promising emerging technology that allows recreating the details of human anatomy. The use of this innovative technology has resulted in improved surgical efficiency and better clinical outcomes. However, its incorporation in gynaecologic surgery has not been widely adopted.

Objectives

To demonstrate the use of Hyper Accuracy 3D reconstruction in a patient with infertility who underwent multiple myomectomy.

Materials and Methods

A stepwise approach describing the incorporation of Hyper Accuracy 3D imaging technology into the preoperative surgical planning and intraoperative guidance of a patient with multiple myomas undergoing multiple myomectomy.

Main outcome measures

Preoperative evaluation of a patient with multiple myoma and infertility who presented to our department seeking surgical management. Hyper Accuracy 3D image was obtained, and a 3D digital image reconstruction of the uterus delineating the exact number, volume, and location of the fibroids was created. The 3D digital image was available during the surgical procedure which helped to plan the surgical steps allowing a systematic surgical approach resulting in an effective surgery with minimal blood loss.

Results

The benefits of intraoperative guidance using Hyper Accuracy 3D in a patient with multiple myomas and infertility are demonstrated.

Conclusions

The adoption of this promising imaging technology into gynaecologic surgery is feasible and should be further investigated. Additional studies evaluating the clinical impact of using Hyper Accuracy 3D imaging in the preoperative planning of patients with gynaecologic surgical pathology are needed.

Increased NaV1.8 expression in patients with sleep-disordered breathing induces pro-arrhythmic activity

Background

Sleep-disordered breathing (SDB) is often associated with atrial fibrillation, but detailed mechanisms remain elusive. Interestingly, late Na current (late INa) has been shown to be increased in patients with SDB, while expression of cardiac Na channel NaV1.5 and peak Na current were decreased. Indeed, recent data demonstrated that enhanced NaV1.8-dependent late INa may also induce pro-arrhythmic activity.

Purpose

We tested whether Na-V1.8 expression and subsequent NaV1.8-dependent pro-arrhythmic activity are increased in patients with SDB.

Methods

We prospectively analysed 29 right atrial appendage biopsies of patients undergoing elective coronary artery bypass grafting. SDB was assessed using polygraphy in the preoperative night and an apnoea-hypopnea index (AHI) ≥15/h defined SDB. Micro-dissected atrial trabeculae were electrically field stimulated (at 1 Hz, 5 V for 50 ms, at 37°C) to elicit regular contractions. Trabecular arrhythmias were induced using 100 nM isoproterenol at [Ca]o of 3.5 mmol/L and pro-arrhythmic activity was scored from 0 (no arrhythmias) to 5 (salve). Sarcoplasmic reticulum Ca leak was estimated by the contractility after paused stimulation (at 2 Hz, normalized to before pause). To correlate functional and expression data for each individual patient, NaV1.8 mRNA expression was quantified in each trabeculum using qPCR.

Results

NaV1.8 mRNA expression was increased in patients with SDB, leading to a significant positive correlation with the severity of SDB (i.e. AHI, p=0.02, r2=0.22, Fig. 1A). Multivariate regression analysis revealed that this association was independent from age, sex, atrial fibrillation, heart failure, diabetes mellitus, and renal function (p=0.03, r2=0.35). Accordingly, selective NaV1.8 blockade with PF-01247324 (PF, 1 μM, 30 min) significantly improved post-pause contractility of isolated trabeculae from 1.69±0.31 to 2.95±0.54 in patients with SDB (p=0.001), whereas no significant improvement was observed in patients without SDB. This resulted in significant positive correlations between the PF-dependent improvement of post-pause contractility and both AHI (p=0.047, r2=0.19) and NaV1.8 mRNA expression (p=0.03, r2=0.17). Most importantly, we also observed a significant increase in arrhythmia severity in patients with SDB of 2.21±0.52 (vs. 1.00±0.49, p=0.03) that could be significantly reduced by selective NaV1.8 inhibition with PF to 0.25±0.18 (p=0.0008, Fig. 1B). In accordance, there was a significant positive correlation between arrhythmia severity and AHI (p=0.01, r2=0.28) that was abolished in the presence of PF (interaction analysis: p=0.ehab724.33141, r2=0.46).

Conclusion

In patients with SDB, enhanced NaV1.8 expression contribute to atrial pro-arrhythmic activity independent from comorbidities. Selective NaV1.8 inhibition may have therapeutic implications for patients with SDB.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Part of the study was supported by grants from Philips Respironics (Murrysville, PA 15668) and the Medical Faculty at the University of Regensburg. Figure 1

The relationship between health IT characteristics and organizational variables among German healthcare workers

Health information technologies (HITs) are widely employed in healthcare and are supposed to improve quality of care and patient safety. However, so far, their implementation has shown mixed results, which might be explainable by understudied psychological factors of human-HIT interaction. Therefore, the present study investigates the association between the perception of HIT characteristics and psychological and organizational variables among 445 healthcare workers via a cross-sectional online survey in Germany. The proposed hypotheses were tested using structural equation modeling. The results showed that good HIT usability was associated with lower levels of techno-overload and lower IT-related strain. In turn, experiencing techno-overload and IT-related strain was associated with lower job satisfaction. An effective error management culture at the workplace was linked to higher job satisfaction and a slightly lower frequency of self-reported medical errors. About 69% of surveyed healthcare workers reported making errors less frequently than their colleagues, suggesting a bias in either the perception or reporting of errors. In conclusion, the study's findings indicate that ensuring high perceived usability when implementing HITs is crucial to avoiding frustration among healthcare workers and keeping them satisfied. Additionally healthcare facilities should invest in error management programs since error management culture is linked to other important organizational variables.

When does risk become residual? A systematic review of research on flood risk management in West Africa

Flood events in West Africa have devastating impacts on the lives of people. Additionally, developments such as climate change, settlement expansion into flood-prone areas, and modification of rivers are expected to increase flood risk in the future. Policy documents have issued calls for conducting local risk assessments and understanding disaster risk in diverse aspects, leading to an increase in such research. Similarly, in a shift from flood protection to flood risk management, the consideration of various dimensions of flood risk, the necessity of addressing flood risk through an integrated strategy containing structural and non-structural measures, and the presence of residual risk are critical perspectives raised. However, the notion of "residual risk" remains yet to be taken up in flood risk management-related academic literature. This systematic review seeks to approach the notion of residual risk by reviewing information on flood impacts, common measures, and recommendations in academic literature. The review reveals various dimensions of impacts from residual flood risk aside from material damage, in particular, health impacts and economic losses. Infrastructural measures were a dominant category of measures before and after flood events and in recommendations, despite their shortcomings. Also, spatial planning interventions, a more participatory and inclusive governance approach, including local knowledge, sensitisation, and early warning systems, were deemed critical. In the absence of widespread access to insurance schemes, support from social networks after flood events emerged as the most frequent measure. This finding calls for in-depth assessments of those networks and research on potential complementary formal risk transfer mechanisms.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10113-021-01826-7.

Single π 0 production off neutrons bound in deuteron with linearly polarized photons

The quasifree γ → d → π 0 n ( p ) photon beam asymmetry, Σ , has been measured at photon energies, E γ , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 ∘ to 148 ∘ . In this kinematic region, polarization observables are sensitive to contributions from the Δ ( 1232 ) and N(1440) resonances. The extracted values of Σ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn-Gatchina analyses; while a revised SAID fit, including the new Σ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict π 0 n photoproduction observables, based on fits to published data in the channels π 0 p , π + n and π - p .

CaMKII Met281/282 oxidation is not required for recovery of calcium transients during acidosis

CaMKII is needed for the recovery of Ca2+ transients during acidosis but also mediates postacidic arrhythmias. CaMKIIδ can sustain its activity following Met281/282 oxidation. Increasing cytosolic Na+ during acidosis as well as postacidic pH normalization should result in prooxidant conditions within the cell favoring oxidative CaMKIIδ activation. We tested whether CaMKIIδ activation through Met281/282 oxidation is involved in recovery of Ca2+ transients during acidosis and promotes cellular arrhythmias post-acidosis. Single cardiac myocytes were isolated from a well-established mouse model in which CaMKIIδ was made resistant to oxidative activation by knock-in replacement of two oxidant-sensitive methionines (Met281/282) with valines (MM-VV). MM-VV myocytes were exposed to extracellular acidosis (pHo 6.5) and compared to wild type (WT) control cells. Full recovery of Ca2+ transients was observed in both WT and MM-VV cardiac myocytes during late-phase acidosis. This was associated with comparably enhanced sarcoplasmic reticulum Ca2+ load and preserved CaMKII specific phosphorylation of phospholamban at Thr17 in MM-VV myocytes. CaMKII was phosphorylated at Thr287, but not Met281/282 oxidized. In line with this, postacidic cellular arrhythmias occurred to a similar extent in WT and MM-VV cells, whereas inhibition of CaMKII using AIP completely prevented recovery of Ca2+ transients during acidosis and attenuated postacidic arrhythmias in MM-VV cells. Using genetically altered cardiomyocytes with cytosolic expression of redox-sensitive green fluorescent protein-2 coupled to glutaredoxin 1, we found that acidosis has a reductive effect within the cytosol of cardiac myocytes despite a significant acidosis-related increase in cytosolic Na+. Our study shows that activation of CaMKIIδ through Met281/282 oxidation is neither required for recovery of Ca2+ transients during acidosis nor relevant for postacidic arrhythmogenesis in isolated cardiac myocytes. Acidosis reduces the cytosolic glutathione redox state of isolated cardiac myocytes despite a significant increase in cytosolic Na+. Pharmacological inhibition of global CaMKII activity completely prevents recovery of Ca2+ transients and protects from postacidic arrhythmias in MM-VV myocytes, which confirms the relevance of CaMKII in the context of acidosis.NEW & NOTEWORTHY The current study shows that activation of CaMKIIδ through Met281/282 oxidation is neither required for CaMKII-dependent recovery of Ca2+ transients during acidosis nor relevant for the occurrence of postacidic cellular arrhythmias. Despite a usually prooxidant increase in cytosolic Na+, acidosis reduces the cytosolic glutathione redox state within cardiac myocytes. This novel finding suggests that oxidation of cytosolic proteins is less likely to occur during acidosis.

Reduced left atrial strain in magnetic resonance imaging is associated with abnormal P-waves in patients after acute myocardial infarction

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): ReForM-B-Program

Background

Abnormal P-wave terminal force in lead V1 (PTFV1) is associated with atrial remodeling. The relationship between PTFV1 and atrial function after acute myocardial injury is insufficiently understood and may be elucidated by detailed feature tracking (FT) strain analysis of cardiac magnetic resonance images (CMR).

Purpose

We investigated the relationship between PTFV1 and left atrial (LA) strain (measured by CMR) in a patient cohort presenting with acute myocardial infarction (MI).

Methods

56 patients with acute MI underwent CMR within 3-5 days after MI. PTFV1 was measured as the product of negative P-wave amplitude and duration in lead V1 (Fig. A). A PTFV1 >4000 ms*µV was defined as abnormal. CMR cine data were retrospectively analyzed using a dedicated FT software. LA strain (ε) and strain rate (SR) for atrial reservoir ([εs]; [SRs]), conduit ([εe]; [SRe]) and booster function ([εa]; [SRa]) were measured in two long-axis views (Fig. A).

Results

Patients with abnormal PTFV1 had significantly reduced LA conduit function εe and SRe (Fig. B + D). There was a significant negative correlation between the extent of PTFV1 and both εe and SRe (Fig. C + E). In univariate and multivariate regression models, both PTFV1 and age predicted atrial conduit function. In contrast, multiple clinical co-factors had no significant influence on εe (Table). Interestingly, linear regression models revealed only mild dependency of PTFV1 on conventional parameters of cardiac function such as left ventricular ejection fraction (p = 0.059; R²(adj.)=0.047), and no dependency on structural parameters such as LA area (p = 0.639; R²(adj.)=0.016), or LA fractional area change (p = 0.825; R²(adj.)=0.020).

Conclusion

Abnormal PTFV1 was associated with reduced LA function independent from numerous clinical co-factors in patients presenting with acute myocardial infarction.

Table N = 56 Linear Regression Analysis Multiple Linear Regression Analysis (R2 (adj.)=0.376, p = 0.016) Variable B 95% CI P value R2 (adj.) B 95% CI P value PTFV1 [µV*ms] -1.628 17085.298 to 27210.854 0.013 0.092 -1.315 -2.614 to -0.016 0.047 Age [y] -425.775 24985.168 to 54634.995 0.002 0.145 -610.815 -982.78 to -238.849 0.001 Body mass indes [kg/m2] -185.653 -3259.187 to 47020.775 0.671 -0.015 -506.096 -1327.357 to 315.165 0.219 Creatinine kinase [U/l] -1.571 14806.991 to 24842.272 0.121 0.027 -1.791 -3.72 to 0.138 0.067 Male sex -893.28 10701.206 to 23504.066 0.802 -0.017 4275.631 -3842.517 to 12393.78 0.292 Estimated glomerular filtration rate [ml/min/1.73m2] 88.617 -4564.177 to 21395.361 0.202 0.012 -163.981 -331.343 to 3.381 0.054 Systolic blood pressure [mmHg] -2.001 14045.786 to 22037.253 0.095 0.038 29.331 -108.243 to 166.906 0.668 nt-pro brain natriuretic peptide [pg/ml] 24.629 -4060.804 to 30920.828 0.716 -0.016 1.015 -1.778 to 3.809 0.466 Univariate and multivariate linear regression models for left atrial conduit strain Abstract Figure

Clonal evolution in diffuse large B-cell lymphoma with central nervous system recurrence

BACKGROUND

The prognosis of patients with secondary central nervous system lymphoma (SCNSL) is poor and despite massive advances in understanding the mutational landscape of primary diffuse large B-cell lymphoma (DLBCL), the genetic comparison to SCNSL is still lacking. We therefore collected paired samples from six patients with DLBCL with available biopsies from a lymph node (LN) at primary diagnosis and the central nervous system (CNS) at recurrence.

PATIENTS AND METHODS

A targeted, massively parallel sequencing approach was used to analyze 216 genes recurrently mutated in DLBCL. Healthy tissue from each patient was also sequenced in order to exclude germline mutations. The results of the primary biopsies were compared with those of the CNS recurrences to depict the genetic background of SCNSL and evaluate clonal evolution.

RESULTS

Sequencing was successful in five patients, all of whom had at least one discordant mutation that was not detected in one of their samples. Four patients had mutations that were found in the CNS but not in the primary LN. Discordant mutations were found in genes known to be important in lymphoma biology such as MYC, CARD11, EP300 and CCND3. Two patients had a Jaccard similarity coefficient below 0.5 indicating substantial genetic differences between the primary LN and the CNS recurrence.

CONCLUSIONS

This analysis gives an insight into the genetic landscape of SCNSL and confirms the results of our previous study on patients with systemic recurrence of DLBCL with evidence of substantial clonal diversification at relapse in some patients, which might be one of the mechanisms of treatment resistance.

Inhibition of cardiac potassium currents by oxidation-activated protein kinase A contributes to early afterdepolarizations in the heart

Reactive oxygen species (ROS) have been shown to prolong cardiac action potential duration resulting in afterdepolarizations, the cellular basis of triggered arrhythmias. As previously shown, protein kinase A type I (PKA I) is readily activated by oxidation of its regulatory subunits. However, the relevance of this mechanism of activation for cardiac pathophysiology is still elusive. In this study, we investigated the effects of oxidation-activated PKA I on cardiac electrophysiology. Ventricular cardiomyocytes were isolated from redox-dead PKA-RI Cys17Ser knock-in (KI) and wild-type (WT) mice and exposed to H₂O₂ (200 µmol/L) or vehicle (Veh) solution. In WT myocytes, exposure to H₂O₂ significantly increased oxidation of the regulatory subunit I (RI) and thus its dimerization (threefold increase in PKA RI dimer). Whole cell current clamp and voltage clamp were used to measure cardiac action potentials (APs), transient outward potassium current (I_to) and inward rectifying potassium current (I_K1), respectively. In WT myocytes, H₂O₂ exposure significantly prolonged AP duration due to significantly decreased I_to and I_K1 resulting in frequent early afterdepolarizations (EADs). Preincubation with the PKA-specific inhibitor Rp-8-Br-cAMPS (10 µmol/L) completely abolished the H₂O₂-dependent decrease in I_to and I_K1 in WT myocytes. Intriguingly, H₂O₂ exposure did not prolong AP duration, nor did it decrease I_to, and only slightly enhanced EAD frequency in KI myocytes. Treatment of WT and KI cardiomyocytes with the late I_Na inhibitor TTX (1 µmol/L) completely abolished EAD formation. Our results suggest that redox-activated PKA may be important for H₂O₂-dependent arrhythmias and could be important for the development of specific antiarrhythmic drugs.NEW & NOTEWORTHY Oxidation-activated PKA type I inhibits transient outward potassium current (I_to) and inward rectifying potassium current (I_K1) and contributes to ROS-induced APD prolongation as well as generation of early afterdepolarizations in murine ventricular cardiomyocytes.

Abnormal P-waves found in patients with sleep-disordered breathing are associated with triggered pro-arrhythmic activity

Background

Sleep-disordered breathing (SDB) is frequently associated with atrial arrhythmias, but diagnostic markers that predict the propensity for atrial arrhythmias are missing. Abnormal P-wave terminal force in lead V1 (PTFV1) has been associated with atrial structural/electrical remodeling and arrhythmias.

Purpose

Here we investigate the association of triggered pro-arrhythmic activity with abnormal PTFV1 in human right atrial appendage biopsies of patients without and with SDB.

Methods

30 patients undergoing elective coronary artery bypass grafting were screened for SDB by polygraphy. An apnoea-hypopnea index (AHI) of ≥15/h defined SDB. PTFV1 was measured as product of negative P-wave amplitude and duration in lead V1 and was defined as abnormal if >4000 ms*μV. Ca/Calmodulin-dependent protein kinase II (CaMKII) activity was measured in human right atrial appendage biopsies by a specific HDAC4 pull-down assay. Premature atrial contractions (PACs) were triggered by exposure to 100 nM isoproterenol (at 3.5 mM [Ca]o) in human atrial trabeculae. PACs severity was classified by a score from 0 points (no arrhythmias) to 5 points (salve). In addition, atrial fibrosis was quantified by Masson's trichrome stain in cryo-sectioned atrial tissue. Multivariate linear regression analyses were performed accounting for age, sex, BMI, existing AF, heart failure, diabetes, and creatinine.

Results

Interestingly, the AHI was independently associated with the magnitude of PTFV1 (fig. A+B, B=57.47±21.03, R2=0.48, P=0.01). Importantly, patients with an abnormal PTFV1 had a significantly increased CaMKII activity (fig. C, P=0.04) and showed significantly more severe triggered PACs (fig. D, P=0.02). Moreover, the magnitude of PTFV1 correlated significantly and independently with PAC severity (fig. D, B=0.0005±0.0002, R2=0.50, P=0.03). Consistently, these arrhythmias could be significantly reduced by acute CaMKII inhibition (5 μM KN93, P<0.01), which abolished the correlation between PTFV1 and PAC severity (P=N.S.). Surprisingly, atrial fibrosis was significantly decreased in patients with an abnormal PTFV1 (fig. E, P=0.02), suggesting that abnormal PTFV1 is a marker of proarrhythmic atrial electrical remodeling of functional cardiomyocytes but not of fibrotic tissue.

Conclusion

The severity of sleep-disordered breathing (AHI) is independently associated with an abnormal PTFV1. Intriguingly, this abnormality is associated with an increased CaMKII activity and with CaMKII-dependent arrhythmias, suggesting PTFV1 to be a potential tool to evaluate the pro-arrhythmic risk of patients with SDB.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Part of this study was funded by Philips Respironics.

Redox-activated protein kinase A Type I (PKA RI) exerts a protective role during pathological pressure overload

Background

Phosphorylation of L-type calcium channels (LTCC) by cAMP-dependent protein kinase A (PKA) increases calcium current (ICa). However, it is unclear if PKA-dependent regulation of ICa is impaired in heart failure (HF) despite evidence for impaired β-adrenergic signaling. Recently, a novel PKA activation pathway by oxidation of regulatory subunit I (RI) has been identified.

Objective

We investigated the impact of redox-activated PKA for regulation of ICa, intracellular calcium (Ca) handling and contractile function in a pressure overload heart failure mouse model.

Methods

Knock-in mice (KI) that lack redox-dependent PKA activation (exchange of cysteine 17 of RI with serine) were compared to wild-type (WT) at baseline, 7 days and 6 weeks after transverse aortic constriction (TAC). Mouse echocardiography was performed to evaluate in-vivo cardiac function. ICa was measured by whole-cell patch clamp, PKA activity, cAMP levels, and protein levels of central Ca handling proteins were assessed at different time points in vitro.

Results

At baseline, no alterations of left ventricular (LV) function (echocardiography) were observed between WT and KI. TAC induced a significant RI oxidation in WT but not KI mice. Despite this difference, at 7 days after TAC, development of LV hypertrophy and impairment of systolic LV function in vivo were similar between WT and KI. Compared to baseline, 7 days after TAC a significant stimulation of peak ICa was observed in WT. In contrast to WT, the stimulation of peak ICa was absent in KI mice at 7 days after TAC. This impairment in peak ICa occurred despite a comparable increase in global PKA activity (ELISA), which was most likely due to increased cAMP levels in our TAC model (assessed by FLIM-FRET). Notably, cAMP levels were comparably increased in between groups (ELISA). Importantly, at 6 weeks after TAC, WT mice showed a mild additional deterioration of systolic LV function in vivo. In contrast, LV function was significantly more impaired in KI mice 6 weeks after TAC, which was accompanied by a significant increase in KI mice mortality. Comparing 6 weeks to 7 days after TAC, there was no stimulation of peak ICa in WT and even a significant decrease in peak ICa in KI mice. In accordance, PKA-dependent LTCC phosphorylation was absent in KI mice 6 weeks after TAC (western blotting).

Conclusion

Redox-activated PKA seems to exert a protective role by stimulation of ICa during pressure overload.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Helicity-Dependent Cross Sections for the Photoproduction of π^{0} Pairs from Nucleons

The double-polarization observable E and helicity-dependent cross sections σ_{1/2}, σ_{3/2} have been measured for the photoproduction of π^{0} pairs off quasifree protons and neutrons at the Mainz MAMI accelerator with the Crystal Ball/TAPS setup. A circularly polarized photon beam was produced by bremsstrahlung from longitudinally polarized electrons and impinged on a longitudinally polarized deuterated butanol target. The reaction products were detected with an almost 4π covering calorimeter. The results reveal for the first time the helicity- and isospin-dependent structure of the γN→Nπ^{0}π^{0} reaction. They are compared to predictions from reaction models in view of nucleon resonance contributions and also to a refit of one model that predicted results for the proton and for the neutron target. The comparison of the prediction and the refit demonstrates the large impact of the new data.

Signatures of the d^{*}(2380) Hexaquark in d(γ,pn[over →])

We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570  MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom. A Legendre polynomial decomposition suggests this behavior could be related to the excitation of the d^{*}(2380) hexaquark.

CaMKII and GLUT1 in heart failure and the role of gliflozins

Empagliflozin, a selective sodium-glucose co-transporter 2 (SGLT2) inhibitor, has been shown to reduce mortality and hospitalization for heart failure in diabetic patients in the EMPA-REG-OUTCOME trial (Zinman et al., 2015). Surprisingly, dapagliflozin, another SGLT2 inhibitor, exerted comparable effects on clinical endpoints even in the absence of diabetes mellitus (DAPA-HF trial) (McMurray et al., 2019). There is a myriad of suggested underlying mechanisms ranging from improved glycemic control and hemodynamic effects to altered myocardial metabolism, inflammation, neurohumoral activation and intracellular ion homeostasis. Here, we review the effects of gliflozins on cardiac electro-mechanical coupling with an emphasis on novel CaMKII-mediated pathways and on cardiac glucose and ketone metabolism in the failing heart. We focus on empagliflozin as it is the gliflozin with the most abundant experimental evidence for direct effects on the heart. Where useful, we aim to compare empagliflozin to other gliflozins. To facilitate understanding of empagliflozin-induced alterations, we first give a short summary of the pathophysiological role of CaMKII in heart failure, as well as cardiac changes of glucose and ketone body metabolism in the failing heart.

Lipoedema – myths and facts, Part 5

The four previous articles in this series addressed the myths and facts surrounding lipoedema. We have shown that there is no scientific evidence at all for the key statements made about lipoedema – which are published time and time again. The main result of this “misunderstanding” of lipoedema is a therapeutic concept that misses the mark. The patient’s real problems are overlooked.

The national and especially the international response to the series, which can be read in both German and English, has been immense and has exceeded all our expectations. The numerous reactions to our articles make it clear that in other countries, too, the fallacies regarding lipoedema have led to an increasing discrepancy between the experience of healthcare workers and the perspective of patients and self-help groups, based on misinformation mostly generated by the medical profession.

Parts 1 to 4 in this series of articles on the myths surrounding lipoedema have made it clear that we have to radically change the view of lipoedema that has been held for decades. Changing our perspective means getting away from the idea of “oedema in lipoedema” – and hence away from the dogma that decongestion is absolutely necessary – and towards the actual problems faced by our patients with lipoedema. Such a paradigm shift in a disease that has been described in the same way for decades cannot be left to individuals but must be put on a much broader footing. For this reason, the lead author of this series of articles invited renowned lipoedema experts from various European countries to discussions on the subject. Experts from seven different countries took part in the two European Lipoedema Forums, with the goal of establishing a consensus. The consensus reflects the experts’ shared view on the disease, having scrutinized the available literature, and having taken into account the many years of clinical practice with this particular patient group. Appropriate to the clinical complexity of lipoedema, participants from different specialties provided an interdisciplinary approach. Nearly all of the participants in the European Lipoedema Forum had already published work on lipoedema, had been involved in drawing up their national lipoedema guidelines, or were on the executive board of their respective specialty society.

In this fifth and final part of our series on lipoedema, we will summarise the relevant findings of this consensus, emphasising the treatment of lipoedema as we now recommend it. As the next step, the actual consensus paper “European Best Practice of Lipoedema” will be issued as an international publication.

Instead of looking at the treatment of oedema, the consensus paper will focus on treatment of the soft tissue pain, as well as the psychological vulnerability of patients with lipoedema. The relationship between pain perception and the patient’s mental health is recognised and dealt with specifically. The consensus also addresses the problem of self-acceptance, and this plays a prominent role in the new therapeutic concept. The treatment of obesity provides a further pillar of treatment. Obesity is recognised as being the most common comorbid condition by far and an important trigger of lipoedema. Bariatric surgery should therefore also be considered for patients with lipoedema who are morbidly obese. The expert group upgraded the importance of compression therapy and appropriate physical activity, as the demonstrated anti-inflammatory effects directly improve the patients’ symptoms. Patients will be provided with tools for personalised self-management in order to sustain sucessful treatment. Should conservative therapy fail to improve the symptoms, liposuction may be considered in strictly defined circumstances.

The change in the view of lipoedema that we describe here brings the patients’ actual symptoms to the forefront. This approach allows us to focus on more comprehensive treatment that is not only more effective but also more sustainable than focusing on the removal of non-existent oedema.

P4521C-reactive protein as a predictor for diastolic dysfunction in patients with sleep-disordered breathing

Background

Sleep-disordered breathing (SDB) is often associated with left ventricular diastolic dysfunction, but the mechanisms are poorly understood. SDB may increase systemic inflammation that could induce myocardial fibrosis leading to diastolic dysfunction.

Purpose

Systemic inflammation and diastolic dysfunction were analysed in patients with SDB.

Methods

295 patients undergoing coronary artery bypass grafting were included in the prospective observational trial CONSIDER-AF (NCT02877745). They were screened for SDB in the preoperative night and an apnoea-hypopnea index (AHI) of ≥15/h defined SDB. Preoperative echocardiography was used to measure the ratio of early (E) and late (A) diastolic transmitral flows (E/A), early diastolic mitral annular velocity (E'), the ratio E/E', LA volume index, and tricuspid regurgitation velocity. Left ventricular diastolic dysfunction was graded I-IV according to current guidelines. Patients with ventricular ejection fraction of less than 45% were excluded. We used serum C-reactive protein (CRP) as a marker for systemic inflammation, resulting in a full data set for 170 patients.

Results

In patients with SDB, serum CRP levels were 3.036 mg/L higher than in control patients (95% confidence interval: −0.393–6.466, P=0.082). Intriguingly, the severity of SDB (AHI) correlated significantly with the CRP levels (coefficient B: 0.13±0.06, P=0.021). CRP also correlated with the severity of diastolic dysfunction (coefficient B: 0.010±0.004, P=0.009). Importantly, multivariable linear regression analysis accounting for the potential confounders age, sex, body-mass index, existing atrial fibrillation, diabetes, AHI, and creatinine indicated that CRP was an independent predictor for the severity of diastolic dysfunction (coefficient B: 0.009±0.004, P=0.016). Interestingly, the latter effect was still present considering just patients with SDB (coefficient B: 0.013±0.005, P=0.015, N=72), but was completely abolished in patients without SDB (coefficient B: 0.001±0.007, P=0.912, N=98), indicating a potential SDB-dependence.

Conclusion

Systemic inflammation (CRP) is associated with the severity of SDB (AHI). Interestingly, only in SDB patients CRP predicts significantly and independently the severity of diastolic dysfunction. Consequently, anti-inflammatory therapeutic strategies could be beneficial for patients with SDB and diastolic dysfunction.

Acknowledgement/Funding

This study was supported by Philips Respironics and the Medical Faculty of the University of Regensburg.

P3508A novel mouse model of sleep-disordered breathing is associated with contractile dysfunction and CaMKII overexpression

Background

Patients with sleep-disordered breathing (SDB) develop arrhythmias and contractile dysfunction, but the mechanisms are poorly understood, possibly due to the lack of mouse models that mimic airway obstruction in spontaneously sleeping mice. Interestingly, New Zealand obese mice have been shown to develop airway obstruction with inspiratory flow limitation resulting in apneas, but these mice also develop diabetes.

Purpose

We developed a novel mouse model of increased airway obstruction in spontaneously sleeping lean mice and investigated the impact on sleep-related apneas and contractile function.

Methods and results

Male C57BL6 mice at 8–12 weeks of age were subjected to polytetrafluoroethylene (PTFE) injection (100 μl) into the tongue. This resulted in an increased tongue volume and reduced pharyngeal luminal diameter. Conscious mice behave normal and there was no difference in body weight between PTFE injected mice and untreated littermates (control). Whole body plethysmography was used to monitor spontaneous breathing for 8h in a quiet environment. Interestingly, compared to control, mice with PTFE injection showed a significantly increased frequency of apneas (lasting >1s, fig. A, * indicated P<0.05, t-test). Echocardiographic analysis revealed that ejection fraction was significantly reduced in PTFE-treated mice 8 weeks after surgery (vs. control, fig. B). In accordance, the developed force of isolated papillary muscles from hearts of PTFE mice was significantly reduced compared to control (fig. C). Ca/calmodulin-dependent protein kinase II (CaMKII) has been implicated in the development of heart failure. Intriguingly, compared to control, CaMKII expression was significantly increased in ventricular heart homogenates of PTFE-treated mice (fig. D). Moreover, the magnitude of CaMKII overexpression correlated significantly with the frequency of apneas (fig. E). Papillary muscle post-pause contractions can be used as measure of diastolic sarcoplasmic reticulum (SR) Ca leak, which is known to be enhanced by CaMKII. Compared to control, post-pause contraction amplitude was significantly smaller in PTFE-treated mice, indicating an increased SR Ca leak (fig. F).

Figure 1

Conclusion

PTFE injection in mice results in an increased frequency of spontaneous apneas. PTFE-treated mice develop mild contractile dysfunction, which is accompanied by CaMKII overexpression. This novel mouse model offers great opportunities for investigation of sleep-related breathing disorders.

Acknowledgement/Funding

This study was supported by the Medical Faculty of the University of Regensburg (ReForM programme).

Antimicrobial resistance of Helicobacter pylori in Germany, 2015 to 2018

OBJECTIVES

National and international guidelines recommend empiric first-line treatments of individuals infected with Helicobacter pylori without prior antimicrobial susceptibility testing. For this reason, knowledge of primary resistance to first-line antibiotics such as clarithromycin is essential. We assessed the primary resistance of H. pylori in Germany to key antibiotics by molecular genetic methods and evaluated risk factors for the development of resistance.

METHODS

Gastric tissue samples of 1851 yet treatment-naïve H. pylori-positive patients were examined with real-time PCR or PCR and Sanger sequencing for mutations conferring resistance to clarithromycin, levofloxacin and tetracycline. Clinical and epidemiological data were documented and univariable and multivariable logistic regression analyses were conducted.

RESULTS

Overall primary resistances were 11.3% (210/1851) to clarithromycin, and 13.4% (201/1497) to levofloxacin; resistance to tetracycline (2.5%, 38/1497) was as low as combined resistance to clarithromycin/levofloxacin (2.6%, 39/1497). Female sex and prior antimicrobial therapies owing to unrelated bacterial infections were risk factors for clarithromycin resistance (adjusted OR (aOR) 2.3, 95% CI 1.6-3.4; and 2.6, 95% CI 1.5-4.5, respectively); older age was associated with levofloxacin resistance (aOR for those ≥65 years compared with those 18-35 years: 6.6, 95% CI 3.1-14.2).

CONCLUSIONS

Clarithromycin might still be recommended in first-line eradication therapies in yet untreated patients, but as nearly every tenth patient may carry clarithromycin-resistant H. pylori it may be advisable to rule out resistance ahead of treatment by carrying out susceptibility testing or prescribing an alternative therapy.