[Impact of the COVID-19 pandemic on the diagnosis and treatment of patients with head and neck cancer in Brandenburg and Berlin]

BACKGROUND

The impact of the COVID-19 pandemic on potential limitations to the diagnosis and treatment of patients with head and neck tumours has not yet been adequately investigated. There are contradictory data on this subject. Data from larger patient collectives do not exist for Germany so far.

OBJECTIVE

The aim of the survey was to clarify in a large cohort whether the COVID-19 pandemic had an influence on the diagnosis and treatment of patients with head and neck tumours.

METHODS

A retrospective data analysis of the reporting data of the Clinical and Epidemiological Cancer Registry of Brandenburg and Berlin (Klinisch-epidemiologischen Krebsregisters Brandenburg-Berlin, KKRBB) of 4831 cases with head and neck tumours from 2018 to 2020 was performed. The period before April 01, 2020, was evaluated as a prepandemic cohort and compared with the cases of the pandemic cohort from April 1, 2020, until December 31, 2020, in terms of patient-related baseline data, tumour location, tumour stage, tumour board and treatments administered.

RESULTS

No differences were observed between the prepandemic and pandemic cohorts with regard to patient-related baseline data, tumour localisation and tumour stage. Likewise, no temporal delay in diagnosis, tumour board and treatment was evident during the pandemic period. On the contrary, the time interval between diagnosis and start of therapy was shortened by an average of 2.7 days in the pandemic phase. Tumours with T4 stage were more frequently treated surgically during the pandemic compared to the period before (20.8% vs. 29.6%), whereas primary radio(chemo)therapy decreased during the pandemic (53.3% vs. 40.4%). For all other tumour stages and entities, there were no differences in treatment.

CONCLUSION

Contrary to initial speculation that the COVID-19 pandemic may have led to a decrease in tumour cases, larger tumour stages at initial presentation and a delay in diagnosis and treatment, the cohort studied for Brandenburg and Berlin showed neither a delay in tumour treatment nor an increase in tumour size and stage at initial presentation. The treatments performed, however, were subject to a change in favour of surgery and it remains to be seen whether this trend will be maintained in the long term.

[Lung transplantation: current situation and developments]

Lung transplantation is currently the gold standard treatment for end-stage lung diseases. Advances in the preservation of donor lungs, the surgical technique and immunosuppressive therapy have led to lung transplantation now being a routine procedure. Nevertheless, the shortage of donor organs, the acute and particularly chronic lung allograft dysfunction (CLAD) still represent major challenges even in experienced centers. Research in this area is still necessary to improve the long-term survival of lung recipients.

Evaluation of treatment delays in hepatopancreatico-biliary surgery during the first COVID-19 wave

INTRODUCTION

The COVID-19 pandemic has caused oncological services worldwide to face unprecedented challenges resulting in treatment disruption for surgical patients. Hepatopancreatico-biliary (HPB) cancers are characterised by rapid disease progression. This study aims to assess delays in receiving surgery for this patient cohort during the first COVID-19 wave.

METHODS

Patients undergoing surgery between April and July 2020 (COVID-19 period) were compared with a control group from the preceding year. Delay in receiving surgery was defined as more than 50 days between referral and surgery date. Statistical analysis was carried out to evaluate predictors of delay and short-term outcomes.

RESULTS

During the COVID-19 and pre-COVID-19 periods, 94 and 115 patients underwent surgery, respectively. No patients contracted COVID-19 postoperatively. Some 118 patients waited more than 50 days for surgery versus 91 who received surgery within 50 days from referral. Independent predictors for surgical delay were undergoing surgery in the COVID-19 era (odds ratio (OR) 2.2, 95% confidence interval (CI) 1.2-4.1; p=0.015), referral pathway (OR 35.1, 95% CI 4.2-296; p=0.001) and presenting pathology (OR 8.3, 95% CI 1.2-56.1; p=0.03). Short-term outcomes were comparable between groups.

CONCLUSIONS

Patient referral pathway and presenting pathology may contribute to delays in undergoing HPB cancer surgery during COVID-19 outbreaks. It is hoped that a better understanding of these factors will aid in designing shifts in healthcare policy during future pandemic outbreaks.

Predictors of recurrence following laparoscopic minor hepatectomy for hepatocellular carcinoma in the UK

AIMS

Minor hepatectomy, which is increasingly carried out laparoscopically (LLR), is a cornerstone of curative treatment for hepatocellular carcinoma (HCC). The majority of relevant publications however originate from regions with endemic viral hepatitis. Although the incidence of HCC in the UK is increasing, little is known about outcomes following LLR.

METHODS

Consecutive patients undergoing minor (involving ≤2 segments) LLR or open resection (OLR) at our institute between 2014 and 2021 were compared. Selection from a plethora of factors potentially impacting on overall (OS) and disease free survival (DFS) was optimised with Lasso regression. To enable analysis of patients having repeat resection, multivariate frailty modelling was utilised to calculate hazard ratios (HR).

RESULTS

The analysis of 111 liver resections included 55 LLR and 56 OLR. LLR was associated with a shorter hospital stay (5 ± 2 vs. 7 ± 2 days; p < 0.001) and a lower comprehensive complication index (4.43 vs. 9.96; p = 0.006). Mean OS (52.3 ± 2.3 vs. 49.9 ± 3.0 months) and DFS (33.9 ± 3.4 vs. 36.5 ± 3.6 months; p = 0.59) were comparable between LLR and OLR, respectively (median not reached). Presence of mixed cholangiocarcinoma/HCC, satellite lesions and AFP level predicted OS and DFS. In addition tumour size was predictive of DFS.

CONCLUSIONS

In the studied population minor LLR was associated with shorter hospital stay and fewer complications while offering non-inferior long-term outcomes. A number of predictors for disease free survival have been elucidated that may aid in identifying patients with a high risk of disease recurrence and need for further treatment.

Associations between prenatal exposure to power plants and birth outcomes across the United States

OBJECTIVES

Although there is growing evidence that in utero exposure to power plants increases the risk of adverse birth outcomes, studies have focused on coal-fired plants and single US locations, limiting generalizability. We used birth certificate data from 50 states and DC to examine the associations between prenatal exposure to power plants and birth outcomes overall and by race/ethnicity.

METHODS

We linked 2009-2018 county-level microdata natality files on 34,674,911 singleton births from 50 states and DC with 9-month county-level averages of power plant fuel consumption based on month/year of birth. We estimated linear regression models for birth weight and gestational age and probit models for the dichotomous outcomes of low birth weight, small for gestational age (SGA), and preterm birth. We subsequently examined interactions between plant fuel consumption and race/ethnicity.

RESULTS

Overall, 69.1% of counties had any power plant fuel consumption. Although we found no overall effects of prenatal exposure to power plants on birth weight or SGA, a significant interaction (both P < 0.01) revealed that a 10% increase in fuel consumption was associated with infants born to White women having slightly lower birth weights (1.76 g; 95% confidence interval = -2.87, -0.65) and higher risk of being born SGA (0.0002; 95% confidence interval = 0.0002, 0.0002).

CONCLUSION

Power plants have negative effects on infant health, which exist independent of locality.

Enhancing Ground-State Population and Macroscopic Coherence of Room-Temperature WS_{2} Polaritons through Engineered Confinement

Exciton polaritons (polaritons herein) in transition-metal dichalcogenide monolayers have attracted significant attention due to their potential for polariton-based optoelectronics. Many of the proposed applications rely on the ability to trap polaritons and to reach macroscopic occupation of their ground energy state. Here, we engineer a trap for room-temperature polaritons in an all-dielectric optical microcavity by locally increasing the interactions between the WS_{2} excitons and cavity photons. The resulting confinement enhances the population and the first-order coherence of the polaritons in the ground state, with the latter effect related to dramatic suppression of disorder-induced inhomogeneous dephasing. We also demonstrate efficient population transfer into the trap when optically injecting free polaritons outside of its periphery.

Primary Treatment Results in Patients with Ovarian, Fallopian or Peritoneal Cancer-Results of a Clinical Cancer Registry Database Analysis in Germany

Background: The current therapy of ovarian cancer is based on the so-called “Three-Pillar-Model”, consisting of surgery, chemotherapy and maintenance therapy. This study represents the first major analysis of a federal cancer database of OC patients from the states Berlin/Brandenburg in Germany. The primary objective was to evaluate the prevailing established quality indicators surgical outcome, adjuvant chemotherapy and integrity of surgical staging in early stages. Methods: Data from the Clinical Cancer Registry for Brandenburg and Berlin of the years 2009−2019 were analyzed. Objectives were defined by a working group of selected physicians. Descriptive statistics were performed, as well as survival analysis. Results: A total of 2771 primary OC cases were included. Results regarding histological subtype met the suspected allocation with predominantly high-grade serous OC in advanced stage. The rate of complete surgical staging in FIGO stages I−IIA was 57%, and the rate of macroscopic complete resection in >FIGO III was 53%. Five-year survival rate varied from 79% (FIGO I) to 40% (FIGO III). Rate of adjuvant chemotherapy was above 50%. Conclusion: The results elucidate quality measurements and treatment results and show good treatment outcomes in patients with primary diagnosis. However, they also indicate deficits and can help to establish new quality indicators to further improve the treatment.

[Epidemiology and surgical treatment of pancreatic cancer in the State of Brandenburg : Analysis of 5418 cases]

BACKGROUND

Pancreatic cancer is the second most frequent cause of death among all forms of cancer in Germany with more than 19,000 deaths per year. The evaluation of the nationwide clinical cancer register aims to depict the reality of treatment and to improve the quality of treatment in the future by targeted analyses.

METHOD

The data from the clinical cancer register of Brandenburg-Berlin for the diagnosis years 2001-2017 were analyzed with respect to the treatment of pancreatic cancer. Data from patients resident in the State of Brandenburg were evaluated with respect to epidemiological and therapeutic parameters.

RESULTS

A total of 5418 patients with pancreatic cancer were documented in the register from 2001 to 2017 and 49.6% of the patients were diagnosed as having the Union for International Cancer Control (UICC) stage IV. A pancreas resection was carried out in 26.4% of the cases. In cases of cancer of the head of the pancreas the most frequent procedure was a pylorus-preserving resection with 51.8% and a pancreatectomy was carried out in 9.4%. The R0 resection rate of all pancreatic cancers in the period from 2014 to 2017 was 61.9%. After R0 resection the 5‑year survival was 19%. Relevant multivariate survival factors were age, UICC stage and the residual (R) tumor classification. The case numbers per hospital had no influence on the absolute survival of patients operated on in the State of Brandenburg.

CONCLUSION

The treatment reality in the State of Brandenburg for patients with pancreatic cancer corresponds to the results of international publications with respect to the key performance indicators investigated. A qualitative internationally comparable treatment of these patients is also possible in nonmetropolitan regions.

Facilitators and barriers to centre- and home-based exercise training in breast cancer patients - a swiss tertiary centre experience

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss Cancer Research

Background

Exercise is an effective therapy for cancer patients to reduce fatigue and to improve health-related quality of life and physical function. Yet, cancer patients often do not meet physical activity guidelines.

Purpose

To understand why recommendations are not met, we aimed at identifying facilitators and barriers to supervised, centre-based exercise within a cardio-oncologic rehabilitation (CORE) programme and to unsupervised, home-based exercise as well as strategies used to manage these barriers.

Methods

Breast cancer patients who had completed a CORE programme at a Swiss tertiary centre were recruited. Semi-structured interviews were conducted with subsequent thematic analysis.

Results

Of 37 eligible breast cancer patients, 19 patients (mean age 48.9±9.7 years) participated to our invitation. Facilitators for centre-based exercise were social support, committedness and provision of structured exercise. Barriers towards centre-based exercise included physical and environmental barriers, while psychological barriers were reported predominantly for home-based exercise. Strategies to manage barriers included the adaptation of training circumstances, behaviour change strategies and strategies to deal with side effects.

Conclusions

Our results support the importance of providing CORE programmes and suggest that a special focus should be directed at the transition from supervised to self-organized exercise in order to enhance long-term exercise participation.

Crossover from exciton-polariton condensation to photon lasing in an optical trap

Optical trapping has been proven to be an effective method of separating exciton-polariton condensates from the incoherent high-energy excitonic reservoir located at the pumping laser position. This technique has significantly improved the coherent properties of exciton-polariton condensates, when compared to a quasi-homogeneous spot excitation scheme. Here, we compare two experimental methods on a sample, where a single spot excitation experiment allowed us only to observe photonic lasing in the weak coupling regime. In contrast, the ring-shaped excitation resulted in the two-threshold behavior, where an exciton-polariton condensate manifests itself at the first and photon lasing at the second threshold. Both lasing regimes are trapped in an optical potential created by the pump. We interpret the origin of this confining potential in terms of repulsive interactions of polaritons with the reservoir at the first threshold and as a result of the excessive free-carrier induced refractive index change of the microcavity at the second threshold. This observation offers a way to achieve multiple phases of photonic condensates in samples, e.g., containing novel materials as an active layer, where two-threshold behavior is impossible to achieve with a single excitation spot.

The proteogenomic subtypes of acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive blood cancer with a poor prognosis. We report a comprehensive proteogenomic analysis of bone marrow biopsies from 252 uniformly treated AML patients to elucidate the molecular pathophysiology of AML in order to inform future diagnostic and therapeutic approaches. In addition to in-depth quantitative proteomics, our analysis includes cytogenetic profiling and DNA/RNA sequencing. We identify five proteomic AML subtypes, each reflecting specific biological features spanning genomic boundaries. Two of these proteomic subtypes correlate with patient outcome, but none is exclusively associated with specific genomic aberrations. Remarkably, one subtype (Mito-AML), which is captured only in the proteome, is characterized by high expression of mitochondrial proteins and confers poor outcome, with reduced remission rate and shorter overall survival on treatment with intensive induction chemotherapy. Functional analyses reveal that Mito-AML is metabolically wired toward stronger complex I-dependent respiration and is more responsive to treatment with the BCL2 inhibitor venetoclax.

Effect of transcutaneous electrical nerve stimulation (TENS) on knee pain and physical function in patients with symptomatic knee osteoarthritis: the ETRELKA randomized clinical trial

OBJECTIVE

To determine the effectiveness of TENS at relieving pain and improving physical function as compared to placebo TENS, and to determine its safety, in patients with knee osteoarthritis.

METHODS

Multi-centre, parallel, 1:1 randomized, double-blind, placebo-controlled clinical trial conducted in six outpatient clinics in Switzerland. We included 220 participants with knee osteoarthritis recruited between October 15, 2012, and October 15, 2014. Patients were randomized to 3 weeks of treatment with TENS (n = 108) or placebo TENS (n = 112). Our pre-specified primary endpoint was knee pain at the end of 3-weeks treatment assessed with the WOMAC pain subscale. Secondary outcome measures included WOMAC physical function subscale and safety outcomes.

RESULTS

There was no difference between TENS and placebo TENS in WOMAC pain at the end of treatment (mean difference -0.06; 95%CI -0.41 to 0.29; P = 0.74), nor throughout the trial duration (P = 0.98). Subgroup analyses did not indicate an interaction between patient/treatment characteristics and treatment effect on WOMAC pain at the end of treatment (P-interaction ≥0.22). The occurrence of adverse events was similar across groups, with 10.4% and 10.6% of patients reporting events in the TENS and placebo TENS groups, respectively (P = 0.95). No relevant differences were observed in secondary outcomes.

CONCLUSIONS

TENS does not improve knee osteoarthritis pain when compared to placebo TENS. Therapists should consider other potentially more effective treatment modalities to decrease knee osteoarthritis pain and facilitate strengthening and aerobic exercise. Our findings are conclusive and further trials comparing TENS and placebo TENS in this patient population are not necessary.

Differences between intrinsic and acquired nucleoside analogue resistance in acute myeloid leukaemia cells

BACKGROUND

SAMHD1 mediates resistance to anti-cancer nucleoside analogues, including cytarabine, decitabine, and nelarabine that are commonly used for the treatment of leukaemia, through cleavage of their triphosphorylated forms. Hence, SAMHD1 inhibitors are promising candidates for the sensitisation of leukaemia cells to nucleoside analogue-based therapy. Here, we investigated the effects of the cytosine analogue CNDAC, which has been proposed to be a SAMHD1 inhibitor, in the context of SAMHD1.

METHODS

CNDAC was tested in 13 acute myeloid leukaemia (AML) cell lines, in 26 acute lymphoblastic leukaemia (ALL) cell lines, ten AML sublines adapted to various antileukaemic drugs, 24 single cell-derived clonal AML sublines, and primary leukaemic blasts from 24 AML patients. Moreover, 24 CNDAC-resistant sublines of the AML cell lines HL-60 and PL-21 were established. The SAMHD1 gene was disrupted using CRISPR/Cas9 and SAMHD1 depleted using RNAi, and the viral Vpx protein. Forced DCK expression was achieved by lentiviral transduction. SAMHD1 promoter methylation was determined by PCR after treatment of genomic DNA with the methylation-sensitive HpaII endonuclease. Nucleoside (analogue) triphosphate levels were determined by LC-MS/MS. CNDAC interaction with SAMHD1 was analysed by an enzymatic assay and by crystallisation.

RESULTS

Although the cytosine analogue CNDAC was anticipated to inhibit SAMHD1, SAMHD1 mediated intrinsic CNDAC resistance in leukaemia cells. Accordingly, SAMHD1 depletion increased CNDAC triphosphate (CNDAC-TP) levels and CNDAC toxicity. Enzymatic assays and crystallisation studies confirmed CNDAC-TP to be a SAMHD1 substrate. In 24 CNDAC-adapted acute myeloid leukaemia (AML) sublines, resistance was driven by DCK (catalyses initial nucleoside phosphorylation) loss. CNDAC-adapted sublines displayed cross-resistance only to other DCK substrates (e.g. cytarabine, decitabine). Cell lines adapted to drugs not affected by DCK or SAMHD1 remained CNDAC sensitive. In cytarabine-adapted AML cells, increased SAMHD1 and reduced DCK levels contributed to cytarabine and CNDAC resistance.

CONCLUSION

Intrinsic and acquired resistance to CNDAC and related nucleoside analogues are driven by different mechanisms. The lack of cross-resistance between SAMHD1/ DCK substrates and non-substrates provides scope for next-line therapies after treatment failure.

430 Evaluation of A Prioritisation Policy for HPB Resections in the COVID-19 Era

Aim

The COVID19 pandemic has caused oncological services worldwide to face unprecedented challenges resulting in treatment disruptions for cancer patients requiring surgery. Hepatopancreatico-biliary cancers are characterised by a low resectability rate and rapid progression. This study aims to assess the effectiveness of a prioritisation policy for this cohort of patients during the initial COVID19 outbreak.

Method

The prioritisation policy and triage system are described in detail. Patients undergoing surgery between April-July 2020 (COVID period) were compared to a control group from the preceding year. Statistical analysis was carried out to evaluate timeliness of treatment, peri-operative characteristics and short-outcomes.

Results

Patient selection was restructured to prioritise patients with performance status of &lt; 2 with presence of cancer complications, borderline resectable- or biologically aggressive disease. Where feasible, neoadjuvant therapy was advocated. An elective safe corridor pathway was established to reduce the risk of COVID19 infection. During the COVID19 and pre-COVID19 period, 94 and 115 patients underwent surgery, respectively. No patients contracted COVID19 post-operatively. There were less patients with ASA≥3 during the COVID19 period vs. pre-COVID19 (12.8% vs. 34.2%; p &lt; 0.001). Median time between referral and surgery was greater during the COVID19 compared to the pre-COVID19 period, at 64 days vs. 49 days, respectively (p = 0.023). Despite this difference no NHS waiting list breaches occurred. Incidence of postoperative complications were comparable between groups.

Conclusions

The outlined prioritisation policy for oncological hepatopancreatico-biliary resections was effective in providing safe surgery during the COVID-19 outbreak. Whether the observed delay in treatment will affect long-term outcomes remains to be seen

Tunable exciton-polaritons emerging from WS2 monolayer excitons in a photonic lattice at room temperature

Engineering non-linear hybrid light-matter states in tailored lattices is a central research strategy for the simulation of complex Hamiltonians. Excitons in atomically thin crystals are an ideal active medium for such purposes, since they couple strongly with light and bear the potential to harness giant non-linearities and interactions while presenting a simple sample-processing and room temperature operability. We demonstrate lattice polaritons, based on an open, high-quality optical cavity, with an imprinted photonic lattice strongly coupled to excitons in a WS2 monolayer. We experimentally observe the emergence of the canonical band-structure of particles in a one-dimensional lattice at room temperature, and demonstrate frequency reconfigurability over a spectral window exceeding 85 meV, as well as the systematic variation of the nearest-neighbour coupling, reflected by a tunability in the bandwidth of the p-band polaritons by 7 meV. The technology presented in this work is a critical demonstration towards reconfigurable photonic emulators operated with non-linear photonic fluids, offering a simple experimental implementation and working at ambient conditions.

[Reality of care of colorectal cancer in the State of Brandenburg : With special consideration of the number of hospital cases and certification as a colorectal cancer center]

Analysis of the quality of care for colorectal cancer is an essential foundation for further development and is based on the comparison of the goals set and the actual quality of care. This publication presents the reality of care in the State of Brandenburg covering the complete spectrum of treating clinics based on the data of the clinical cancer register. This study analyzed the number of resected and examined lymph nodes, the quality of total mesorectal excision (TME), the residual tumor (R0) resection rate and the proportion of adjuvant therapy of colon cancer in Union internationale contre le cancer (UICC) stage III depending on the operation quota of hospitals and the certification as bowel cancer center according to Onkozert. Apart from the R status, the analyses showed no differences in the qualitative operation data from the clinical cancer register depending on the hospital volume.

Performance of image guided navigation in laparoscopic liver surgery - A systematic review

BACKGROUND

Compared to open surgery, minimally invasive liver resection has improved short term outcomes. It is however technically more challenging. Navigated image guidance systems (IGS) are being developed to overcome these challenges. The aim of this systematic review is to provide an overview of their current capabilities and limitations.

METHODS

Medline, Embase and Cochrane databases were searched using free text terms and corresponding controlled vocabulary. Titles and abstracts of retrieved articles were screened for inclusion criteria. Due to the heterogeneity of the retrieved data it was not possible to conduct a meta-analysis. Therefore results are presented in tabulated and narrative format.

RESULTS

Out of 2015 articles, 17 pre-clinical and 33 clinical papers met inclusion criteria. Data from 24 articles that reported on accuracy indicates that in recent years navigation accuracy has been in the range of 8-15 mm. Due to discrepancies in evaluation methods it is difficult to compare accuracy metrics between different systems. Surgeon feedback suggests that current state of the art IGS may be useful as a supplementary navigation tool, especially in small liver lesions that are difficult to locate. They are however not able to reliably localise all relevant anatomical structures. Only one article investigated IGS impact on clinical outcomes.

CONCLUSIONS

Further improvements in navigation accuracy are needed to enable reliable visualisation of tumour margins with the precision required for oncological resections. To enhance comparability between different IGS it is crucial to find a consensus on the assessment of navigation accuracy as a minimum reporting standard.

The impact of photobiomodulation on the chondrogenic potential of adipose-derived stromal/stem cells

Due to their capacity to differentiate into the chondrogenic lineage, adipose-derived stromal/stem cells (ASC) are a promising source of therapeutically relevant cells for cartilage tissue regeneration. Their differentiation potential, however, varies between patients. In our study, we aim to stimulate ASC towards a more reliable chondrogenic phenotype using photobiomodulation (PBM). LED devices of either blue (475 nm), green (516 nm) or red (635 nm) light were used to treat human ASC from donors of varying chondrogenic potential. The treatment was applied either once during the 2D expansion phase or repeatedly during the 3D differentiation phase. Chondrogenic differentiation was assessed via pellet size, GAG/DNA content, histology and gene expression analysis. Reactions to PBM were found to be wavelength-dependent and more pronounced when the treatment was applied during expansion. Donors were assigned to responder categories according to their response to the treatment during expansion, whereby good responders were mainly donors with low intrinsic chondrogenic potential. Exposed to light, they revealed a particularly high relative increase in pellet size (more than twice the size of untreated controls after red light PBM), intense collagen type II immunostaining (low/absent in untreated controls) and activation of otherwise absent COL2A1 expression. Conversely, on a donor with high intrinsic chondrogenic potential, light had adverse effects. When applied with shorter wavelengths (blue, green), it led to reduced pellet size, GAG/DNA content and collagen type II immunostaining. However, when PBM was applied in 3D, the same donor was the only one to react with increased differentiation to all three wavelengths. We were able to demonstrate that PBM can be used to enhance or hamper chondrogenesis of ASC, and that success depends on treatment parameters and intrinsic cellular potential. The improvement of chondrogenesis in donors with low intrinsic potential highlights PBM as potent tool for cell-based cartilage regeneration. Its cost-effectiveness and ease of use make for an attractive treatment option to enhance the performance of ASC in cartilage tissue engineering.

Propagative Oscillations in Codirectional Polariton Waveguide Couplers

We report on novel exciton-polariton routing devices created to study and purposely guide light-matter particles in their condensate phase. In a codirectional coupling device, two waveguides are connected by a partially etched section that facilitates tunable coupling of the adjacent channels. This evanescent coupling of the two macroscopic wave functions in each waveguide reveals itself in real space oscillations of the condensate. This Josephson-like oscillation has only been observed in coupled polariton traps so far. Here, we report on a similar coupling behavior in a controllable, propagative waveguide-based design. By controlling the gap width, channel length, or propagation energy, the exit port of the polariton flow can be chosen. This codirectional polariton device is a passive and scalable coupler element that can serve in compact, next generation logic architectures.

Evaluation of the combination of endothelin receptor antagonists (ERA) and phosphodiesterase-5 inhibitors for the treatment of pulmonary arterial hypertension (PAH) in pathologic human pulmonary arteries in an ex-vivo organ bath model

PURPOSE

Medical combination therapy of pulmonary arterial hypertension (PAH) may alleviate the drawbacks of monotherapy by avoiding drug tolerance and by increasing effectiveness, as shown by the combination of ambrisentan and tadalafil (AMBITION trial). The present ex-vivo study evaluated the combination of the endothelin receptor antagonists (ERA) macitentan and bosentan with the phosphodiesterase-5 (PDE-5) inhibitor vardenafil in pulmonary arteries from patients suffering from terminal lung disease as a model of PAH.

METHODS

Segments of the pulmonary vessels were excised from resected lungs of patients requiring lung transplantation (LTX). Contraction of pulmonary arteries (PA) was elicited by consecutive dose-response curves of endothelin-1 (ET-1) followed by norepinephrine (NE) to allow inhibition by different pathways. Forces were measured isometrically in an organ bath in the presence and absence of ERA and PDE-5 inhibitors and their combination.

RESULTS

PA of 38 patients were examined between October 2016 and November 2019. Bosentan (1E-7 M) and macitentan (1E-8 M, 3E-8 M, 1E-7 M) inhibited ET-1 induced contractions, whereas vardenafil (1E-6 M, 3E-6 M, 1E-5 M) inhibited only the NE induced part of the contractions. Vardenafil enhanced bosentan-induced inhibition of vasoconstriction in a dose-dependent fashion. Combination effects exceeded single bosentan at 3E-6 M and 1E-5 M vardenafil, and they exceeded single vardenafil at the lower vardenafil concentrations. Macitentan showed a more pronounced inhibition than bosentan regardless of the lower concentrations. Accordingly, combination effects with vardenafil resembled those of macitentan alone.

CONCLUSIONS

Macitentan and bosentan were potent antagonists of vasoconstriction in PA of LTX patients. The benefit of drug combinations was demonstrated at selected concentrations only owing to a narrow therapeutic range of vardenafil in this ex-vivo model. These results suggest the utility of drug combinations other than the established pair of ambrisentan and tadalafil in PAH treatment but also make a case for a further assessment of vasodilator properties of drugs complementing ERA.

Observation of Intensity Squeezing in Resonance Fluorescence from a Solid-State Device

Intensity squeezing-i.e., photon number fluctuations below the shot-noise limit-is a fundamental aspect of quantum optics and has wide applications in quantum metrology. It was predicted in 1979 that intensity squeezing could be observed in resonance fluorescence from a two-level quantum system. However, its experimental observation in solid states was hindered by inefficiencies in generating, collecting, and detecting resonance fluorescence. Here, we report the intensity squeezing in a single-mode fiber-coupled resonance fluorescence single-photon source based on a quantum dot-micropillar system. We detect pulsed single-photon streams with 22.6% system efficiency, which show sub-shot-noise intensity fluctuation with an intensity squeezing of 0.59 dB. We estimate a corrected squeezing of 3.29 dB at the first lens. The observed intensity squeezing provides the last piece of the fundamental picture of resonance fluorescence, which can be used as a new standard for optical radiation and in scalable quantum metrology with indistinguishable single photons.

Prognostic relevance of the posterior resection margin for predicting disease free survival in ampullary adenocarcinoma

BACKGROUND

Pancreaticoduodenectomy is the only curative treatment option for patients with resectable ampullary adenocarcinoma (AA). Excellent disease free survival (DFS) can be achieved in patients with clear resection margins but it is poorly understood which patients are at increased risk of recurrence and hence would benefit from adjuvant chemotherapy. There is evolving evidence that the anatomical location of incomplete resection margins influences DFS in pancreatic adenocarcinoma. It is unknown if this also pertains to AA and therefore this study aimed to assess individual resection margin status and other predictors of DFS in AA.

MATERIAL & METHODS

Consecutive patients undergoing pancreaticoduodenectomy for AA at our institution from 1996 to 2017 were analysed. Pancreas neck, posterior and superior mesenteric vein margins were assessed individually. Cox proportional hazards modelling was used to identify predictors of 5-year DFS. Factors with p < 0.1 on univariate analysis were included for multivariate analysis.

RESULTS

Analysis of 104 patients revealed median OS and DFS of 56 and 34 months, respectively. Predictors associated with worse DFS on multivariate analysis were T3-stage (HR 3.6, p = 0.048), N1 (HR 2.9, p = 0.01) and N2 -stage (HR 3.6, p = 0.006), R1 status at the posterior margin (HR 3.0, p = 0.009) and a visible mass on CT (HR 2.0, p = 0.039).

CONCLUSION

Routine histopathological assessment of individual resection margins may aid in predicting recurrence of AA. Future studies to assess if routine mesopancreas excision during pancreaticoduodenectomy can reduce the incidence of R1 status at the posterior margin are warranted.

SAMHD1 is a key regulator of the lineage-specific response of acute lymphoblastic leukaemias to nelarabine

The nucleoside analogue nelarabine, the prodrug of arabinosylguanine (AraG), is effective against T-cell acute lymphoblastic leukaemia (T-ALL) but not against B-cell ALL (B-ALL). The underlying mechanisms have remained elusive. Here, data from pharmacogenomics studies and a panel of ALL cell lines reveal an inverse correlation between nelarabine sensitivity and the expression of SAMHD1, which can hydrolyse and inactivate triphosphorylated nucleoside analogues. Lower SAMHD1 abundance is detected in T-ALL than in B-ALL in cell lines and patient-derived leukaemic blasts. Mechanistically, T-ALL cells display increased SAMHD1 promoter methylation without increased global DNA methylation. SAMHD1 depletion sensitises B-ALL cells to AraG, while ectopic SAMHD1 expression in SAMHD1-null T-ALL cells induces AraG resistance. SAMHD1 has a larger impact on nelarabine/AraG than on cytarabine in ALL cells. Opposite effects are observed in acute myeloid leukaemia cells, indicating entity-specific differences. In conclusion, SAMHD1 promoter methylation and, in turn, SAMHD1 expression levels determine ALL cell response to nelarabine.

Demonstration of a polariton step potential by local variation of light-matter coupling in a van-der-Waals heterostructure

The large oscillator strength of excitons in transition metal dichalcogenide layers facilitates the formation of exciton-polariton resonances for monolayers and van-der-Waals heterostructures embedded in optical microcavities. Here, we show, that locally changing the number of layers in a WSe₂/hBN/WSe₂ van-der-Waals heterostructure embedded in a monolithic, high-quality-factor cavity gives rise to a local variation of the coupling strength. This effect yields a polaritonic stair case potential, which we demonstrate at room temperature. Our result paves the way towards engineering local polaritonic potentials at length scales down to atomically sharp interfaces, based on purely modifying its real part contribution via the coherent light-matter coupling strength g.

Room temperature organic exciton-polariton condensate in a lattice

Interacting Bosons in artificial lattices have emerged as a modern platform to explore collective manybody phenomena and exotic phases of matter as well as to enable advanced on-chip simulators. On chip, exciton–polaritons emerged as a promising system to implement and study bosonic non-linear systems in lattices, demanding cryogenic temperatures. We discuss an experiment conducted on a polaritonic lattice at ambient conditions: We utilize fluorescent proteins providing ultra-stable Frenkel excitons. Their soft nature allows for mechanically shaping them in the photonic lattice. We demonstrate controlled loading of the coherent condensate in distinct orbital lattice modes of different symmetries. Finally, we explore the self-localization of the condensate in a gap-state, driven by the interplay of effective interaction and negative effective mass in our lattice. We believe that this work establishes organic polaritons as a serious contender to the well-established GaAs platform for a wide range of applications relying on coherent Bosons in lattices.

Many studies of polariton condensates have been limited to low temperatures. Here the authors demonstrate ambient polariton condensation in lattices using organic traps that profit from the stability of organic excitons and the large Rabi splitting.

Trimethylamine-N-oxide is elevated in the acute phase after ischaemic stroke and decreases within the first days

BACKGROUND AND PURPOSE

Trimethylamine-N-oxide (TMAO) is a biomarker of the gut microbiome and correlates with the risk of cardiovascular diseases. However, conflicting data exist on the specific role of TMAO in ischaemic stroke patients. We aimed to analyze the time course of TMAO levels in stroke patients compared with controls.

METHODS

In this prospective, case-control study, patients suffering from ischaemic stroke (onset <24 h) and control patients with less than two cardiovascular risk factors were enrolled. Plasma TMAO levels were analyzed on admission, after 48 h and after 3 months. The primary endpoint was the difference in TMAO levels on admission between stroke patients and controls.

RESULTS

A total of 196 patients with ischaemic stroke and 100 controls were included between February 2018 and April 2019. Plasma TMAO levels on admission were significantly higher in stroke patients than in controls [median value 4.09 (2.87-6.49) vs. 3.16 (2.08-5.16) µmol/L, P = 0.001]. There was a significant decrease in TMAO levels in stroke patients after 48 h [median at 48 h, 3.49 (2.30-5.39) µmol/L, P = 0.027]. TMAO levels increased again 3 months after stroke [median 4.23 (2.92-8.13) µmol/L, P = 0.047]. In controls, TMAO levels did not change between admission and after 48 h [median at 48 h, 3.14 (1.63-4.61) µmol/L, P = 0.11]. An inverse correlation between TMAO values and kidney function was found (Spearman rho -0.334, P < 0.001).

CONCLUSIONS

Our study emphasizes the importance of the time course of TMAO levels after ischaemic stroke. Future studies should define the time point of TMAO analysis, preferably in the acute phase (<24 h).