Intracranial complications of sinogenic and otogenic infections in children: an ESPN survey on their occurrence in the pre-COVID and post-COVID era

BACKGROUND

COVID-19 pandemic is thought to have changed the epidemiology of some pediatric neurosurgical disease: among them are the intracranial complications of sinusitis and otitis (ICSO). According to some studies on a limited number of cases, both streptococci-related sinusitis and ICSO would have increased immediately after the pandemic, although the reason is not clear yet (seasonal changes versus pandemic-related effects). The goal of the present survey of the European Society for Pediatric Neurosurgery (ESPN) was to collect a large number of cases from different European countries encompassing the pre-COVID (2017-2019), COVID (2020-2021), and post-COVID period (2022-June 2023) looking for possible epidemiological and/or clinical changes.

MATERIAL AND METHODS

An English language questionnaire was sent to ESPN members about year of the event, patient's age and gender, presence of immune-deficit or other favoring risk factors, COVID infection, signs and symptoms at onset, site of primary infection, type of intracranial complication, identified germ, type and number of surgical operations, type and duration of medical treatment, clinical and radiological outcome, duration of the follow-up.

RESULTS

Two hundred fifty-four cases were collected by 30 centers coming from 14 different European countries. There was a statistically significant difference between the post-COVID period (129 children, 86 cases/year, 50.7% of the whole series) and the COVID (40 children, 20 cases/year, 15.7%) or the pre-COVID period (85 children, 28.3 cases/year, 33.5%). Other significant differences concerned the presence of predisposing factors/concurrent diseases (higher in the pre-COVID period) and previous COVID infection (higher in the post-COVID period). No relevant differences occurred as far as demographic, microbiological, clinical, radiological, outcome, morbidity, and mortality data were concerned. Paranasal sinuses and middle ear/mastoid were the most involved primary site of infection (71% and 27%, respectively), while extradural or subdural empyema and brain abscess were the most common ICSO (73% and 17%, respectively). Surgery was required in 95% of cases (neurosurgical and ENT procedure in 71% and 62% of cases, respectively) while antibiotics in 99% of cases. After a 12.4-month follow-up, a full clinical and radiological recovery was obtained in 85% and 84% of cases, respectively. The mortality rate was 2.7%.

CONCLUSIONS

These results suggest that the occurrence of ICSO was significantly increased after the pandemic. Such an increase seems to be related to the indirect effects of the pandemic (e.g., immunity debt) rather than to a direct effect of COVID infection or to seasonal fluctuations. ICSO remain challenging diseases but the pandemic did not affect the management strategies nor their prognosis. The epidemiological change of sinusitis/otitis and ICSO should alert about the appropriate follow-up of children with sinusitis/otitis.

Life expectancy associated with different ages at diagnosis of type 2 diabetes in high-income countries: 23 million person-years of observation

BACKGROUND

The prevalence of type 2 diabetes is increasing rapidly, particularly among younger age groups. Estimates suggest that people with diabetes die, on average, 6 years earlier than people without diabetes. We aimed to provide reliable estimates of the associations between age at diagnosis of diabetes and all-cause mortality, cause-specific mortality, and reductions in life expectancy.

METHODS

For this observational study, we conducted a combined analysis of individual-participant data from 19 high-income countries using two large-scale data sources: the Emerging Risk Factors Collaboration (96 cohorts, median baseline years 1961-2007, median latest follow-up years 1980-2013) and the UK Biobank (median baseline year 2006, median latest follow-up year 2020). We calculated age-adjusted and sex-adjusted hazard ratios (HRs) for all-cause mortality according to age at diagnosis of diabetes using data from 1 515 718 participants, in whom deaths were recorded during 23·1 million person-years of follow-up. We estimated cumulative survival by applying age-specific HRs to age-specific death rates from 2015 for the USA and the EU.

FINDINGS

For participants with diabetes, we observed a linear dose-response association between earlier age at diagnosis and higher risk of all-cause mortality compared with participants without diabetes. HRs were 2·69 (95% CI 2·43-2·97) when diagnosed at 30-39 years, 2·26 (2·08-2·45) at 40-49 years, 1·84 (1·72-1·97) at 50-59 years, 1·57 (1·47-1·67) at 60-69 years, and 1·39 (1·29-1·51) at 70 years and older. HRs per decade of earlier diagnosis were similar for men and women. Using death rates from the USA, a 50-year-old individual with diabetes died on average 14 years earlier when diagnosed aged 30 years, 10 years earlier when diagnosed aged 40 years, or 6 years earlier when diagnosed aged 50 years than an individual without diabetes. Using EU death rates, the corresponding estimates were 13, 9, or 5 years earlier.

INTERPRETATION

Every decade of earlier diagnosis of diabetes was associated with about 3-4 years of lower life expectancy, highlighting the need to develop and implement interventions that prevent or delay the onset of diabetes and to intensify the treatment of risk factors among young adults diagnosed with diabetes.

FUNDING

British Heart Foundation, Medical Research Council, National Institute for Health and Care Research, and Health Data Research UK.

Intensive cholesterol-lowering treatment reduces synovial inflammation during early collagenase-induced osteoarthritis, but not pathology at end-stage disease in female dyslipidemic E3L.CETP mice

INTRODUCTION

The association between metabolic syndrome (MetS) and osteoarthritis (OA) development has become increasingly recognized. In this context, the exact role of cholesterol and cholesterol-lowering therapies in OA development has remained elusive. Recently, we did not observe beneficial effects of intensive cholesterol-lowering treatments on spontaneous OA development in E3L.CETP mice. We postulated that in the presence of local inflammation caused by a joint lesion, cholesterol-lowering therapies may ameliorate OA pathology.

MATERIALS AND METHODS

Female ApoE3∗Leiden.CETP mice were fed a cholesterol-supplemented Western type diet. After 3 weeks, half of the mice received intensive cholesterol-lowering treatment consisting of atorvastatin and the anti-PCSK9 antibody alirocumab. Three weeks after the start of the treatment, OA was induced via intra-articular injections of collagenase. Serum levels of cholesterol and triglycerides were monitored throughout the study. Knee joints were analyzed for synovial inflammation, cartilage degeneration, subchondral bone sclerosis and ectopic bone formation using histology. Inflammatory cytokines were determined in serum and synovial washouts.

RESULTS

Cholesterol-lowering treatment strongly reduced serum cholesterol and triglyceride levels. Mice receiving cholesterol-lowering treatment showed a significant reduction in synovial inflammation (P = 0.008, WTD: 95% CI: 1.4- 2.3; WTD + AA: 95% CI: 0.8- 1.5) and synovial lining thickness (WTD: 95% CI: 3.0-4.6, WTD + AA: 95% CI: 2.1-3.2) during early-stage collagenase-induced OA. Serum levels of S100A8/A9, MCP-1 and KC were significantly reduced after cholesterol-lowering treatment (P = 0.0005, 95% CI: -46.0 to -12.0; P = 2.8 × 10^-10, 95% CI: -398.3 to -152.1; P = 2.1 × 10^-9, -66.8 to -30.4, respectively). However, this reduction did not reduce OA pathology, determined by ectopic bone formation, subchondral bone sclerosis and cartilage damage at end-stage disease.

CONCLUSION

This study shows that intensive cholesterol-lowering treatment reduces joint inflammation after induction of collagenase-induced OA, but this did not reduce end stage pathology in female mice.

The alarmins high mobility group box protein 1 and S100A8/A9 display different inflammatory profiles after acute knee injury

OBJECTIVE

To compare the concentrations of high mobility group box 1 protein (HMGB1) and S100A8/A9 in synovial fluid between patients with knee injuries and osteoarthritis (OA), and knee healthy subjects. To investigate associations of alarmin levels with different joint injuries and with biomarkers of inflammation, Wnt signaling, complement system, bone and cartilage degradation.

METHODS

HMGB1 and S100A8/A9 were measured in synovial fluid by immunoassays in patients with knee injuries, with OA and from knee healthy subjects, and were related to time from injury and with biomarkers obtained from previous studies. Hierarchical cluster and enrichment analyses of biomarkers associated to HMGB1 and S100A8/A9 were performed.

RESULTS

The synovial fluid HMGB1 and S100A8/A9 concentrations were increased early after knee injury; S100A8/A9 levels were negatively associated to time after injury and was lower in the old compared to recent injury group, while HMGB1 was not associated to time after injury. The S100A8/A9 levels were also increased in OA. The initial inflammatory response was similar between the alarmins, and HMGB1 and S100A8/A9 shared 9 out of 20 enriched pathways. The alarmins displayed distinct response profiles, HMGB1 being associated to cartilage biomarkers while S100A8/A9 was associated to proinflammatory cytokines.

CONCLUSIONS

HMGB1 and S100A8/A9 are increased as an immediate response to knee trauma. While they share many features in inflammatory and immunoregulatory mechanisms, S100A8/A9 and HMGB1 are associated to different downstream responses, which may have impact on the OA progression after acute knee injuries.

POS1385 INTERNATIONAL CONSENSUS FOR ULTRASOUND DEFINITIONS OF TENOSYNOVITIS IN JUVENILE IDIOPATHIC ARTHRITIS: RESULTS OF A DELPHI PROCESS

Background

Musculoskeletal Ultrasonography (US) is a suitable tool for the clinical assessment in juvenile idiopathic arthritis (JIA). Recently US definitions for normal components of pediatric joints and synovitis have been developed by the OMERACT US working group. Currently this group is working on development and validation of US definition for tenosynovitis as it is also an essential prerequisite for the reliable use of this technology in the pediatric age group.

Objectives

To produce consensus-based definitions for US tenosynovitis in JIA through a Delphi process.

Methods

We undertook a Delphi process on US-defined tenosynovitis in children that consisted of two steps. As a prior systematic literature review showed that US anatomy of the tendons is similar to adults, a Delphi questionnaire was written based on the consensual definitions developed for and used in adults with rheumatoid arthritis [1, 2]. The Delphi questionnaire was sent to rheumatologists and pediatricians who perform pediatric US examination, asking them to rate their level of agreement with each statement of US-defined tenosynovitis. Group agreement was considered if ≥80% of responders scored an item as either 4 or 5.

In the second step, the definitions were validated on 88 standardized US images displaying various degrees of tenosynovitis obtained from JIA patients at various ages. Tendons often involved in JIA were selected (foot and ankle tendons, hand and wrist tendons, bicep tendon.). US images of both normal and tenosynovitis elementary lesions were collected by the 18 experts participating in the OMERACT US task force on pediatric tenosynovitis. An agreement ≥70% was considered mandatory for accepting the definition as applicable in the rated image.

Results

The response rate was 75% (28 out of 37) from the first Delphi questionnaire. Strong group agreement (≥86%) was obtained for the US definitions tested. The response rate was 88.9% (16 out of 18) from the Web-exercise after four rounds. The final definitions were validated on still images for all tendons, except for the biceps tenosynovitis in the age group 2-4 years (the definitions of elementary lesions and the global definition of tenosynovitis) as no image was available for this location and age group. Despite not reaching group agreement after the second and the third round for the US-defined normal finger pulley in children aged 8 years and younger (roughly 68% and 69% respectively), it reached a score of 99.8% after the fourth round.

Conclusion

US definitions of tenosynovitis and its elementary components covering a wide pediatric age range were successfully developed through a Delphi questionnaire and validated in a web-based still images exercise. These results provide the basis for the standardized US assessment of tenosynovitis in clinical practice.

References

[1]Ultrasound in the assessment of tenosynovitis in juvenile idiopathic arthritis: systematic literature review. Collado P on behalf of the OMERACT Ultrasound Task Force. DOI: 10.1136/annrheumdis-2019-eular.3493

[2]Reliability of a consensus-based ultrasound score for tenosynovitis in rheumatoid arthritis. Naredo E on behalf of the OMERACT Ultrasound Task Force. Ann Rheum Dis 2013;72:1328

Acknowledgements

AG Bruyn, L Terslev, S Jousse-Joulin, A Rodriguez, M Steiner, E Inarejos, P Bøyesen, K Misaki, A Iagnocco, B Marston, T Cazenave, P Mandl, A Bruns.

Disclosure of Interests

None declared

Mapping genomic loci implicates genes and synaptic biology in schizophrenia

Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies.

Neural network guided adjoint computations in dual weighted residual error estimation

Abstract

In this work, we are concerned with neural network guided goal-oriented a posteriori error estimation and adaptivity using the dual weighted residual method. The primal problem is solved using classical Galerkin finite elements. The adjoint problem is solved in strong form with a feedforward neural network using two or three hidden layers. The main objective of our approach is to explore alternatives for solving the adjoint problem with greater potential of a numerical cost reduction. The proposed algorithm is based on the general goal-oriented error estimation theorem including both linear and nonlinear stationary partial differential equations and goal functionals. Our developments are substantiated with some numerical experiments that include comparisons of neural network computed adjoints and classical finite element solutions of the adjoints. In the programming software, the open-source library deal.II is successfully coupled with LibTorch, the PyTorch C++ application programming interface.

Article Highlights

Distinct tumor-infiltrating lymphocyte landscapes are associated with clinical outcomes in localized non-small-cell lung cancer

BACKGROUND

Despite the importance of tumor-infiltrating T lymphocytes (TILs) in cancer biology, the relationship between TIL phenotypes and their prognostic relevance for localized non-small-cell lung cancer (NSCLC) has not been well established.

PATIENTS AND METHODS

Fresh tumor and normal adjacent tissue was prospectively collected from 150 patients with localized NSCLC. Tissue was comprehensively characterized by high-dimensional flow cytometry of TILs integrated with immunogenomic data from multiplex immunofluorescence, T-cell receptor sequencing, exome sequencing, RNA sequencing, targeted proteomics, and clinicopathologic features.

RESULTS

While neither the magnitude of TIL infiltration nor specific TIL subsets were significantly prognostic alone, the integration of high-dimensional flow cytometry data identified two major immunotypes (IM1 and IM2) that were predictive of recurrence-free survival independent of clinical characteristics. IM2 was associated with poor prognosis and characterized by the presence of proliferating TILs expressing cluster of differentiation 103, programmed cell death protein 1, T-cell immunoglobulin and mucin-domain containing protein 3, and inducible T-cell costimulator. Conversely, IM1 was associated with good prognosis and differentiated by an abundance of CD8⁺ T cells expressing cytolytic enzymes, CD4⁺ T cells lacking the expression of inhibitory receptors, and increased levels of B-cell infiltrates and tertiary lymphoid structures. While increased B-cell infiltration was associated with good prognosis, the best prognosis was observed in patients with tumors exhibiting high levels of both B cells and T cells. These findings were validated in patient tumors from The Cancer Genome Atlas.

CONCLUSIONS

Our study suggests that although the number of infiltrating T cells is not associated with patient survival, the nature of the infiltrating T cells, resolved in distinct TIL immunotypes, is prognostically relevant in NSCLC and may inform therapeutic approaches to clinical care.

A single dose of anti-IL-1β antibodies prevents Western diet-induced immune activation during early stage collagenase-induced osteoarthritis, but does not ameliorate end-stage pathology

OBJECTIVE

Metabolic dysfunction can cause IL-1β mediated activation of the innate immune system, which could have important implications for the therapeutic efficacy of IL-1β neutralizing drugs as treatment for OA in the context of metabolic syndrome (MetS). In the present study, we investigated whether early treatment with a single dose of IL-1β blocking antibodies could prevent Western diet (WD) induced changes to systemic monocyte populations and their cytokine secretion profile and herewith modulate collagenase induced osteoarthritis (CiOA) pathology.

METHODS

CiOA was induced in female C57Bl/6 mice fed either a standard diet (SD) or WD and treated with a single dose of either polyclonal anti-IL-1β antibodies or control. Monocyte subsets and granulocytes in bone marrow and blood were analyzed with flow cytometry, and cytokine expression by bone marrow cells was analyzed using qPCR. Synovial cellularity, cartilage damage and osteophyte formation were assessed on histology.

RESULTS

WD feeding of C57Bl/6 mice led to increased serum levels of low-density lipoprotein (LDL) and innate immune activation in the form of an increased number of Ly6C^high cells in bone marrow and blood and increased cytokine expression of IL-6 and TNF-α by bone marrow cells. The increase in monocyte number and activity was ameliorated by anti-IL-1β treatment. However, anti-IL-1β treatment did not significantly affect synovial lining thickness, cartilage damage and ectopic bone formation during WD feeding.

CONCLUSIONS

Single-dose systemic anti-IL-1β treatment prevented WD-induced innate immune activation during early stage CiOA in C57Bl/6 mice, but did not ameliorate joint pathology.

Antipsychotics in routine treatment are minor contributors to QT prolongation compared to genetics and age

BACKGROUND

Drug-induced prolongation of cardiac repolarization limits the treatment with many psychotropic drugs. Recently, the contribution of polygenic variation to the individual duration of the QT interval was identified.

AIMS

To explore the interaction between antipsychotic drugs and the individual polygenic influence on the QT interval.

METHODS

Retrospective analysis of clinical and genotype data of 804 psychiatric inpatients diagnosed with a psychotic disorder. The individual polygenic influence on the QT interval was calculated according to the method of Arking et al.

RESULTS

Linear regression modelling showed a significant association of the individual polygenic QT interval score (ß_std = 0.176, p < 0.001) and age (ß_std = 0.139, p < 0.001) with the QTc interval corrected according to Fridericia's formula. Sex showed a nominal trend towards significance (ß_std = 0.064, p = 0.064). No association was observed for the number of QT prolonging drugs according to AZCERT taken. Subsample analysis (n = 588) showed a significant association of potassium serum concentrations with the QTc interval (ß_std = -0.104, p = 0.010). Haloperidol serum concentrations were associated with the QTc interval only in single medication analysis (n = 26, ß_std = 0.101, p = 0.004), but not in multivariate regression analysis. No association was observed for aripiprazole, clozapine, quetiapine and perazine, while olanzapine and the sum of risperidone and its metabolite showed a negative association.

CONCLUSIONS

Individual genetic factors and age are main determinants of the QT interval. Antipsychotic drug serum concentrations within the therapeutic range contribute to QTc prolongation on an individual level.

Genome-wide association study of more than 40,000 bipolar disorder cases provides new insights into the underlying biology

Bipolar disorder is a heritable mental illness with complex etiology. We performed a genome-wide association study of 41,917 bipolar disorder cases and 371,549 controls of European ancestry, which identified 64 associated genomic loci. Bipolar disorder risk alleles were enriched in genes in synaptic signaling pathways and brain-expressed genes, particularly those with high specificity of expression in neurons of the prefrontal cortex and hippocampus. Significant signal enrichment was found in genes encoding targets of antipsychotics, calcium channel blockers, antiepileptics and anesthetics. Integrating expression quantitative trait locus data implicated 15 genes robustly linked to bipolar disorder via gene expression, encoding druggable targets such as HTR6, MCHR1, DCLK3 and FURIN. Analyses of bipolar disorder subtypes indicated high but imperfect genetic correlation between bipolar disorder type I and II and identified additional associated loci. Together, these results advance our understanding of the biological etiology of bipolar disorder, identify novel therapeutic leads and prioritize genes for functional follow-up studies.

Efficacy of Retreatment After Failed Direct-acting Antiviral Therapy in Patients With HCV Genotype 1-3 Infections

Hepatitis C virus infection is causing chronic liver disease, cirrhosis, and hepatocellular carcinoma. By combining direct-acting antivirals (DAAs), high sustained virologic response rates (SVRs) can be achieved. Resistance-associated substitutions (RASs) are commonly observed after DAA failure, and especially nonstructural protein 5A (NS5A) RASs may impact retreatment options.^1-3 Data on retreatment of DAA failure patients using first-generation DAAs are limited.^4-7 Recently, a second-generation protease- and NS5A-inhibitor plus sofosbuvir (voxilaprevir/velpatasvir/sofosbuvir [VOX/VEL/SOF]) was approved for retreatment after DAA failure.⁸ However, this and other second-generation regimens are not available in many resource-limited countries or are not reimbursed by regular insurance, and recommendations regarding the selection of retreatment regimens using first-generation DAAs are very important. This study aimed to analyze patients who were re-treated with first-generation DAAs after failure of a DAA combination therapy.

TROPHY registry - status report

INTRODUCTION

The TROPHY registry has been established to conduct an international multicenter prospective data collection on the surgical management of neonatal intraventricular hemorrhage (IVH)-related hydrocephalus to possibly contribute to future guidelines. The registry allows comparing the techniques established to treat hydrocephalus, such as external ventricular drainage (EVD), ventricular access device (VAD), ventricular subgaleal shunt (VSGS), and neuroendoscopic lavage (NEL). This first status report of the registry presents the results of the standard of care survey of participating centers assessed upon online registration.

METHODS

On the standard of treatment forms, each center indicated the institutional protocol of interventions performed for neonatal post-hemorrhagic hydrocephalus (nPHH) for a time period of 2 years (Y1 and Y2) before starting the active participation in the registry. In addition, the amount of patients enrolled so far and allocated to a treatment approach are reported.

RESULTS

According to the standard of treatment forms completed by 56 registered centers, fewer EVDs (Y1 55% Y2 46%) were used while more centers have implemented NEL (Y1 39%; Y2 52%) to treat nPHH. VAD (Y1 66%; Y2 66%) and VSGS (Y1 42%; Y2 41%) were used at a consistent rate during the 2 years. The majority of the centers used at least two different techniques to treat nPHH (43%), while 27% used only one technique, 21% used three, and 7% used even four different techniques. Patient data of 110 infants treated surgically between 9/2018 and 2/2021 (13% EVD, 15% VAD, 30% VSGS, and 43% NEL) were contributed by 29 centers.

CONCLUSIONS

Our results emphasize the varying strategies used for the treatment of nPHH. The international TROPHY registry has entered into a phase of growing patient recruitment. Further evaluation will be performed and published according to the registry protocol.

Super-Resolution Microscopy and Single-Molecule Tracking Reveal Distinct Adaptive Dynamics of MreB and of Cell Wall-Synthesis Enzymes

The movement of filamentous, actin-like MreB and of enzymes synthesizing the bacterial cell wall has been proposed to be highly coordinated. We have investigated the motion of MreB and of RodA and PbpH cell wall synthesis enzymes at 500 ms and at 20 ms time scales, allowing us to compare the motion of entire MreB filaments as well as of single molecules with that of the two synthesis proteins. While all three proteins formed assemblies that move with very similar trajectory orientation and with similar velocities, their trajectory lengths differed considerably, with PbpH showing shortest and MreB longest trajectories. These experiments suggest different on/off rates for RodA and PbpH at the putative peptidoglycan-extending machinery (PGEM), and during interaction with MreB filaments. Single molecule tracking revealed distinct slow-moving and freely diffusing populations of PbpH and RodA, indicating that they change between free diffusion and slow motion, indicating a dynamic interaction with the PGEM complex. Dynamics of MreB molecules and the orientation and speed of filaments changed markedly after induction of salt stress, while there was little change for RodA and PbpH single molecule dynamics. During the stress adaptation phase, cells continued to grow and extended the cell wall, while MreB formed fewer and more static filaments. Our results show that cell wall synthesis during stress adaptation occurs in a mode involving adaptation of MreB dynamics, and indicate that Bacillus subtilis cell wall extension involves an interplay of enzymes with distinct binding kinetics to sites of active synthesis.

Fast TIRF-SIM imaging of dynamic, low-fluorescent biological samples

Fluorescence microscopy is the standard imaging technique to investigate the structures and dynamics of living cells. However, increasing the spatial resolution comes at the cost of temporal resolution and vice versa. In addition, the number of images that can be taken in sufficiently high quality is limited by fluorescence bleaching. Hence, super-resolved imaging at several Hertz of low fluorescent biological samples is still a big challenge and, especially in structured illumination microscopy (SIM), is often visible as imaging artifacts. In this paper, we present a TIRF-SIM system based on scan-mirrors and a Michelson interferometer, which generates images at 110 nm spatial resolution and up to 8 Hz temporal resolution. High resolution becomes possible by optimizing the illumination interference contrast, even for low fluorescent, moving samples. We provide a framework and guidelines on how the modulation contrast, which depends on laser coherence, polarization, beam displacement or sample movements, can be mapped over the entire field of view. In addition, we characterize the influence of the signal-to-noise ratio and the Wiener filtering on the quality of reconstructed SIM images, both in real and frequency space. Our results are supported by theoretical descriptions containing the parameters leading to image artifacts. This study aims to help microscopists to better understand and adjust optical parameters for structured illumination, thereby leading to more trustworthy measurements and analyses of biological dynamics.

More recent, better designed studies have weakened links between antidiabetes medications and cancer risk

BACKGROUND

An increasing number of studies have investigated associations of antidiabetes medications with cancer risk. Antidiabetes medications are classified by their mechanisms of action on tissues and organs. They potentially act as both causative and confounding factors in the temporal association of diabetes and cancer.

AIM

To present the current evidence regarding both the carcinogenic and anti-carcinogenic effects of antidiabetes medications on cancer in humans.

METHODS

A review of the scientific literature.

RESULTS

The most conclusive evidence shown of an association of antidiabetes medication with a specific cancer was for that of the thiazolidinedione pioglitazone with bladder cancer. Currently, there is inconclusive evidence regarding a possible association of incretin therapies, drugs of the dipeptidyl peptidase-4 inhibitor class, with the risk of pancreatic cancer. Insulin, sulfonylureas, metformin and sodium-glucose co-transporter-2 inhibitors appear not to be associated with increased risk of any cancer. Sparse evidence suggests possible protective effects against cancer incidence of metformin, sulfonylureas, thiazolidinediones, incretin-based drugs and sodium-glucose co-transporter-2 inhibitors.

CONCLUSION

The conflicting evidence regarding associations of antidiabetes medications with cancer risk is apparently attributable to both methodological issues and to the complexity of the subject. More recent and better-designed studies have weakened the evidence for links between antidiabetes medications and cancer risk.

De novo mutations identified by exome sequencing implicate rare missense variants in SLC6A1 in schizophrenia

Schizophrenia is a highly polygenic disorder with important contributions from both common and rare risk alleles. We analysed exome-sequencing data for de novo variants (DNVs) in a new sample of 613 schizophrenia trios, and combined this with published data for a total of 3,444 trios. In our new data, loss-of-function (LoF) DNVs were significantly enriched among 3,471 LoF intolerant genes, supporting previous findings. In the full dataset, genes associated with neurodevelopmental disorders (n=159) were significantly enriched for LoF DNVs. Within these neurodevelopmental disorder genes, SLC6A1, encoding a gamma-aminobutyric acid transporter, was associated with missense-damaging DNVs. In 1,122 trios for which we had genome-wide common variant data, schizophrenia and bipolar disorder polygenic risk were significantly over-transmitted to probands. Probands carrying LoF or deletion DNVs in LoF intolerant or neurodevelopmental disorder genes had significantly less over-transmission of schizophrenia polygenic risk than non-carriers, providing robust support for these DNVs increasing liability to schizophrenia.

Dynamics of a Protein Chain Motor Driving Helical Bacteria under Stress

The wall-less, helical bacterial genus Spiroplasma has a unique propulsion system; it is not driven by propeller-like flagella but by a membrane-bound, cytoplasmic, linear motor that consists of a contractile chain of identical proteins spanning the entire cell length. By a coordinated spread of conformational changes of the proteins, kinks propagate in pairs along the cell body. However, the mechanisms for the initiation or delay of kinks and their coordinated spread remain unclear. Here, we show how we manipulate the initiation of kinks, their propagation velocities, and the time between two kinks for a single cell trapped in an optical line potential. By interferometric three-dimensional shape tracking, we measured the cells' deformations in response to various external stress situations. We observed a significant dependency of force generation on the cells' local ligand concentrations (likely ATP) and ligand hydrolysis, which we altered in different ways. We developed a mechanistic, mathematical model based on Kramer's rates, describing the subsequent cooperative and conformational switching of the chain's proteins. The model reproduces our experimental observations and can explain deformation characteristics even when the motor is driven to its extreme. Nature has invented a set of minimalistic mechanical driving concepts. To understand or even rebuild them, it is essential to reveal the molecular mechanisms of such protein chain motors, which need only two components-coupled proteins and ligands-to function.

The role of NOX2-derived reactive oxygen species in collagenase-induced osteoarthritis

OBJECTIVE

Synovitis in collagenase-induced osteoarthritis (CiOA) is driven by locally released S100A8/A9 proteins and enhances joint destruction. S100A8/A9 can induce reactive oxygen species (ROS) release by phagocytes in OA synovium via neutrophil cytosolic factor-1 (Ncf1)-regulated NOX2 activation. In the present study we investigated whether NOX2-derived ROS affect joint pathology during CiOA.

METHODS

CiOA was induced in knee joints of wild type (WT) and Ncf1-deficient (Ncf1**) mice. Synovial gene expression of NOX2-subunits was measured with quantitative real-time polymerase chain reaction (qRT-PCR). Joint pathology was assessed using histology and immunohistochemistry for aggrecan neo-epitope VDIPEN. Levels of inflammatory proteins were measured with Luminex or ELISA. Phagocytes in synovium, blood, bone marrow (BM) and spleen were analyzed with flow cytometry. ROS release by phagocytes was measured with a ROS detection kit.

RESULTS

CiOA induction in knee joints of WT mice caused significantly increased synovial gene expression of NOX2 subunits. On day 7 of CiOA, cartilage damage and MMP activity, as measured by VDIPEN, were comparable between WT and Ncf1** mice. Synovial thickening, synovial S100A8/A9 levels and percentages of synovial macrophages, polymorphonuclear cells (PMNs), and monocytes were not different, as were levels of inflammatory mediators in serum and phagocyte percentages in blood, BM and spleen. On day 42 of CiOA, synovitis, cartilage damage, and osteophyte formation in Ncf1** mice were unaltered when compared to WT mice. ROS detection confirmed that Ncf1** PMNs lack functional NOX2, but in vitro macrophages showed ROS production, suggesting activation of compensatory mechanisms.

CONCLUSIONS

Absence of Ncf1-mediated ROS production does not alter joint pathology in CiOA.

Multiple Brain Developmental Venous Anomalies as a Marker for Constitutional Mismatch Repair Deficiency Syndrome

BACKGROUND AND PURPOSE

Biallelic constitutional mutations in DNA mismatch repair genes cause a distinct syndrome, constitutional mismatch repair deficiency syndrome (CMMRD), characterized by cancers from multiple organs, most commonly brain tumors, during childhood. Surveillance protocols include total and brain MR imaging among other modalities to enable early detection of tumors. Brain surveillance scans revealed prominent brain developmental venous anomalies (DVAs) in some patients. DVAs are benign vascular anomalies, and their incidence in the general population is 2.6%-6.4%. Most developmental venous anomalies are asymptomatic and are found incidentally. Our purpose was to assess the prevalence of DVAs in CMMRD patients and describe their phenotype.

MATERIALS AND METHODS

A retrospective descriptive analysis of brain MR imaging studies from 10 patients from 3 families with CMMRD was performed. Analysis included the number of developmental venous anomalies, location, draining vessels, and associated vascular anomalies (ie, cavernomas), with clinical correlation of symptoms and tumors.

RESULTS

All 10 patients had ≥2 developmental venous anomalies, and 2 had, in addition, non-therapy-induced cavernomas. There was no clinically symptomatic intracranial bleeding from developmental venous anomalies. Six patients had malignant brain tumors. The location of brain tumors was not adjacent to the developmental venous anomalies. No new developmental venous anomalies developed during follow-up.

CONCLUSIONS

The occurrence of multiple developmental venous anomalies in all our patients with CMMRD suggests that developmental venous anomalies may be a characteristic of this syndrome that has not been previously described. If confirmed, this quantifiable feature can be added to the current scoring system and could result in early implementation of genetic testing and surveillance protocols, which can be life-saving for these patients.

Brewer's yeast is a potent inducer of fever, sickness behavior and inflammation within the brain

Brewer's yeast, derived from the yeast species Saccharomyces cerevisiae (S. cerevisiae), is commonly used for inducing pyrexia in pharmacological studies screening antipyretics in rats. Despite its widespread use, the peripheral and central inflammatory response associated with Brewer's yeast-induced fever and sickness behavior in rats has not been investigated. Thus, we injected male Sprague-Dawley rats (150-200 g) subcutaneously with a high (4 g/kg, n = 9), medium (2 g/kg, n = 5) or low (0.4 g/kg, n = 6) dose of Brewer's yeast solution or saline (0.9%, n = 6) and measured core body temperature, cage activity, food intake and body mass for six days after injection. Blood and brain samples were collected at 2, 8, 18 and 72 h after injection; n = 5-7 per time point. Brewer's yeast administration dose-dependently induced fever, lethargy, anorexia and body mass stunting that was accompanied by increased blood plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α and activation of inflammatory transcription factors (nuclear factor (NF) for interleukin-6, signal transducer and activator of transcription (STAT)-3, and NF-κB)) in the hypothalamus and circumventricular organs. The increased activation of transcription factors following Brewer's yeast administration was accompanied by increased hypothalamic mRNA expression of TNF-α, IL-1β and IL-6 and rate-limiting enzymes for prostaglandin synthesis. Our results show that subcutaneous administration of S. cerevisae induces prolonged fever, anorexia and lethargy that is accompanied by a pronounced increase in the synthesis of pro-inflammatory cytokines, key prostaglandin synthesizing enzymes and transcription factors, in the periphery and brain.

Diagnostic exome sequencing in early-onset Parkinson's disease confirms VPS13C as a rare cause of autosomal-recessive Parkinson's disease

Parkinson's disease (PD) is a genetically heterogeneous disorder and new putative disease genes are discovered constantly. Therefore, whole-exome sequencing could be an efficient approach to genetic testing in PD. To evaluate its performance in early-onset sporadic PD, we performed diagnostic exome sequencing in 80 individuals with manifestation of PD symptoms at age 40 or earlier and a negative family history of PD. Variants in validated and candidate disease genes and risk factors for PD and atypical Parkinson syndromes were annotated, followed by further analysis for selected variants. We detected pathogenic variants in Mendelian genes in 6.25% of cases and high-impact risk factor variants in GBA in 5% of cases, resulting in overall maximum diagnostic yield of 11.25%. One individual was compound heterozygous for variants affecting canonical splice sites in VPS13C, confirming the causal role of protein-truncating variants in this gene linked to autosomal-recessive early-onset PD. Despite the low diagnostic yield of exome sequencing in sporadic early-onset PD, the confirmation of the recently discovered VPS13C gene highlights its advantage over using predefined gene panels.

Buccal Respiratory Chain Complexes I and IV Quantities in Huntington's Disease Patients

Alterations in mitochondrial parameters are an important hallmark of Huntington's disease (HD). The ubiquitous expression of mutant huntingtin raises the prospect that mitochondrial disturbances can also be detected and monitored through buccal epithelial cells. In a group of 34 patients with Huntington's disease and a group of 22 age-related healthy volunteers, respiratory complex I and IV protein quantities in buccal epithelial cells were measured using the dipstick immunocapture assay. The protein quantity of respiratory complex I correlates with age (r = 0.427, P = 0.026, FWE-P = 0.156) in the patient group, but not in the group of healthy subjects. Our non-invasive approach allows us to obtain valuable information for the studies of mitochondrial biochemical parameters in patients with neurodegenerative diseases and could also be useful in epidemiological studies.