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Determination of the Pathological Features of NPC1 Variants in a Cellular Complementation Test
(2019)
Niemann-Pick Type C (NP-C) is a rare disorder of lipid metabolism caused by mutations
within the NPC1 and NPC2 genes. NP-C is a neurovisceral disease leading to a heterogeneous,
multisystemic spectrum of symptoms in those affected. Until now, there is no investigative tool to
demonstrate the significance of single variants within the NPC genes. Hence, the aim of the study
was to establish a test that allows for an objective assessment of the pathological potential of NPC1
gene variants. Chinese hamster ovary cells defective in the NPC1 gene accumulate cholesterol in
lysosomal storage organelles. The cells were transfected with NPC1-GFP plasmid vectors carrying
distinct sequence variants. Filipin staining was used to test for complementation of the phenotype.
The known variant p.Ile1061Thr showed a significantly impaired cholesterol clearance after 12 and
24 h compared to the wild type. Among the investigated variants, p.Ser954Leu and p.Glu1273Lys
showed decelerated cholesterol clearance as well. The remaining variants p.Gln60His, p.Val494Met,
and p.Ile787Val showed a cholesterol clearance indistinguishable from wild type. Further, p.Ile1061Thr
acquired an enhanced clearance ability upon 25-hydroxycholesterol treatment. We conclude that the
variants that caused an abnormal clearance phenotype are highly likely to be of clinical relevance.
Moreover, we present a system that can be utilized to screen for new drugs.
Generation of Inducible BCL11B Knockout in TAL1/LMO1 Transgenic Mouse T Cell Leukemia/Lymphoma Model
(2022)
The B-cell CLL/lymphoma 11B gene (BCL11B) plays a crucial role in T-cell development, but its role in T-cell malignancies is still unclear. To study its role in the development of T-cell neoplasms, we generated an inducible BCL11B knockout in a murine T cell leukemia/lymphoma model. Mice, bearing human oncogenes TAL BHLH Transcription Factor 1 (TAL1; SCL) or LIM Domain Only 1 (LMO1), responsible for T-cell acute lymphoblastic leukemia (T-ALL) development, were crossed with BCL11B floxed and with CRE-ER/lox mice. The mice with a single oncogene BCL11Bflox/floxCREtg/tgTAL1tg or BCL11Bflox/floxCREtg/tgLMO1tg were healthy, bred normally, and were used to maintain the mice in culture. When crossed with each other, >90% of the double transgenic mice BCL11Bflox/floxCREtg/tgTAL1tgLMO1tg, within 3 to 6 months after birth, spontaneously developed T-cell leukemia/lymphoma. Upon administration of synthetic estrogen (tamoxifen), which binds to the estrogen receptor and activates the Cre recombinase, the BCL11B gene was knocked out by excision of its fourth exon from the genome. The mouse model of inducible BCL11B knockout we generated can be used to study the role of this gene in cancer development and the potential therapeutic effect of BCL11B inhibition in T-cell leukemia and lymphoma.
MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are involved in the modulation of the DNA-damage response (DDR) and upon exposure to ionizing radiation (IR), their expression fluctuates. In this study, we propose a workflow that enables the creation of regulatory networks by integrating transcriptomics data as well as regulatory data in order to better understand the interplay between genes, transcription factors (TFs), miRNAs, and lncRNAs in the cellular response to IR. We preprocessed and analyzed publicly available gene expression profiles and then applied our consensus and integration approach using open source data and tools. To exemplify the benefits of our proposed workflow, we identified a total of 32 differentially expressed transcripts corresponding to 20 unique differentially expressed genes (DEGs) and using these DEGs, we constructed a regulatory network consisting of 106 interactions and 100 nodes (11 DEGs, 78 miRNAs, 1 DEG acting as a TF, and 10 lncRNAs). Overrepresentation analyses (ORAs) furthermore linked our DEGs and miRNAs to annotations pertaining to the DDR and to IR. Our results show that MDM2 and E2F7 function as network hubs, and E2F7, miR-25-3p, let-7a-5p, and miR-497-5p are the four nodes with the highest betweenness centrality. In brief, our workflow, that is based on open source data and tools, and that generates a regulatory network, provides novel insights into the regulatory mechanisms involving miRNAs and lncRNAs in the cellular response to IR.
Pancreatic necroses are a major challenge in the treatment of patients with pancreatitis, causing high morbidity. When indicated, these lesions are usually drained endoscopically using plastic or metal stents. However, data on factors associated with the occurrence of failure or adverse events during stent therapy are scarce. We retrospectively analyzed all adverse events and their associated features which occurred in patients who underwent a first-time endoscopic drainage of pancreatic necrosis from 2009 to 2019. During the observation period, a total of 89 eligible cases were identified. Adverse events occurred in 58.4% of the cases, of which 76.9% were minor (e.g., stent dislocation, residual lesions, or stent obstruction). However, these events triggered repeated interventions (63.5% vs. 0%, p < 0.001) and prolonged hospital stays (21.0 [11.8–63.0] vs. 14.0 [7.0–31.0], p = 0.003) compared to controls without any adverse event. Important factors associated with the occurrence of adverse events during endoscopic drainage therapy were positive necrosis cultures (6.1 [2.3–16.1], OR [95% CI], p < 0.001) and a larger diameter of the treated lesion (1.3 [1.1–1.5], p < 0.001). Superinfection of pancreatic necrosis is the most significant factor increasing the likelihood of adverse events during endoscopic drainage. Therefore, control of infection is crucial for successful drainage therapy, and future studies need to consider superinfection of pancreatic necrosis as a possible confounding factor when comparing different therapeutic modalities.
Stroke is the leading neurological cause of
adult long-term disability in Europe. Even though functional
consequences directly related to neurological impairment
are well studied, post-stroke trajectories of functional
health according to the International Classification of
Functioning, Disability and Health are poorly understood.
Particularly, no study investigated the relationship between
post-stroke trajectories of activities of daily living (ADL)
and self-rated health (SRH). However, such knowledge
is of major importance to identify patients at risk of
unfavourable courses. This prospective observational
study aims to investigate trajectories of ADL and SRH, and
their modifying factors in the course of the first year after
stroke.
Methods and analysis The study will consecutively enrol
300 patients admitted to a tertiary care hospital with acute
ischaemic stroke or transient ischaemic attack (TIA; Age,
Blood Pressure, Clinical Features, Duration of symptoms,
Diabetes score ≥3). Patient inclusion is planned from May
2021 to September 2022. All participants will complete
an interview assessing ADL, SRH, mental health, views
on ageing and resilience-related concepts. Participants
will be interviewed face-to-face 1–5 days post-stroke/
TIA in the hospital; and will be followed up after 6 weeks,
3 months, 6 months and 12 months via telephone. The
12-month follow-up will also include a neurological
assessment. Primary endpoints are ADL operationalised
by modified Rankin Scale scores and SRH. Secondary
outcomes are further measures of ADL, functional health,
physical activity, falls and fatigue. Views on ageing, social
support, resilience-related concepts, affect, frailty, illness
perceptions and loneliness will be examined as modifying
factors. Analyses will investigate the bidirectional
relationship between SRH and ADL using bivariate latent
change score models.
Ethics and dissemination The study has been approved
by the institutional review board of the University
Medicine Greifswald (Ref. BB 237/20). The results
will be disseminated through scientific publications,
conferences and media. Moreover, study results and
potential implications will be discussed with patient
representatives.
Injection of intense low-energy reactor-based positron beams into a supported magnetic dipole trap
(2020)
Abstract
An increased low-energy positron flux is obtained from the reactor based NEPOMUC source when using its primary beam at energies as low as 20 eV. First experiments with this beam in a supported magnetic dipole trap resulted in the maximum current of injected positrons to date. According to single-particle simulations, remaining limitations in the injection efficiency, observed in the experiment, can be attributed to the spatial spread of the beam. In the first trapping measurements with this beam, top-down asymmetries in the electrostatic trapping potential are found to be detrimental to confinement.
Primary tooth trauma occurs commonly during the development of motor coordination. Its consequences do not only affect the traumatized primary tooth but may affect the underlying permanent successor as well. Its management may involve very high costs on patients and insurance companies and complicated injuries can have negative effects on the quality of life of preschool children. Investigating the causes and patterns of trauma in primary teeth are highly needed to aim for preventive measures. This retrospective study compared the patterns of dental trauma injuries at the trauma center at Greifswald University/Germany for a recent pediatric cohort (2014-16, 103 children) with a historic one before the German unification and the health care system reformation (1974-1989, n=120). The data contained details on etiology, injury types and treatment delivered for 450 injured teeth (247 historic, 203 recent). In both cohorts, the occurrence was more common in males than females (63%/55%, resp.) with an age peak from 2 to 6 years. Maxillary incisors were most affected (89.6%/88.6%, resp.) and periodontal ligament injuries dominated (77.8%/90.3%, resp.).
Almost half of the injuries occurred at home (46.6%), mostly due to falling (48.5%) or during playing (37.8%) in the recent pediatric cohort which provided better forensic data due to insurance issues and potential concern about child abuse. Advice and follow up was the most common approach in the recent pediatric cohort (76%).
Trauma patterns in the primary dentition seem to be rather universal due to the activities of small children and their anatomic conditions. Trauma to primary dentition occurred mostly at home or in the nurseries and possibly is hard to avoid due to falls or accidents during normal playing. Even after 30 years and a change in the health care system due to German unification, the patterns remain similar.
2
Titin is a multifunctional filamentous protein anchored in the M-band, a hexagonally organized supramolecular lattice in the middle of the muscle sarcomere. Functionally, the M-band is a framework that cross-links myosin thick filaments, organizes associated proteins, and maintains sarcomeric symmetry via its structural and putative mechanical properties. Part of the M-band appears at the C-terminal end of isolated titin molecules in the form of a globular head, named here the “M-complex”, which also serves as the point of head-to-head attachment of titin. We used high-resolution atomic force microscopy and nanosurgical manipulation to investigate the topographical and internal structure and local mechanical properties of the M-complex and its associated titin molecules. We find that the M-complex is a stable structure that corresponds to the transverse unit of the M-band organized around the myosin thick filament. M-complexes may be interlinked into an M-complex array that reflects the local structural and mechanical status of the transversal M-band lattice. Local segments of titin and the M-complex could be nanosurgically manipulated to achieve extension and domain unfolding. Long threads could be pulled out of the M-complex, suggesting that it is a compact supramolecular reservoir of extensible filaments. Nanosurgery evoked an unexpected volume increment in the M-complex, which may be related to its function as a mechanical spacer. The M-complex thus displays both elastic and plastic properties which support the idea that the M-band may be involved in mechanical functions within the muscle sarcomere.
We decided to develop a short-form of the CHC-SUN/YHC-SUN, a questionnaire aiming at assessing health care satisfaction of children and adolescents with chronic health conditions. Data analysis was based on samples from three different studies. Item selection involved statistical analysis and expert consensus. For independent validation purposes, we calculated descriptive statistics on single-item and composite-scale levels and applied classic test theory, confirmatory factor analyses, and correlation analysis to investigate the psychometric properties of the final short-form by different types of reliability and validity. Internal consistency (Cronbach’s Alpha) reached values of a = 0.89 (self-report) and a = 0.92 (parents report), split-half reliability values reached 0.85 (self-report) and 0.91 (parents report). Confirmatory factor analysis indicated no sufficient fit for the single factor solution, whereas the solution with three factors and one higher order factor indicated the best overall fit amongst three competing models. Validity of the short-form measure can be assumed, e.g., as indicated by its association with a single-item measure on general health care satisfaction. The short-form measures of the CHC-SUN for parents (CHC-SUN-SF) and the YHC-SUN self-report version for adolescents (YHC-SUN-SF) feature excellent psychometric performances, provide economical assessments, and are easy-to-administer questionnaires. They should be used whenever brief measures are needed for economic reasons.
ObjectivesComprehensive protocols are key for the planning and conduct of randomised clinical trials (RCTs). Evidence of low reporting quality of RCT protocols led to the publication of the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklist in 2013. We aimed to examine the quality of reporting of RCT protocols from three countries before and after the publication of the SPIRIT checklist.DesignRepeated cross sectional study.SettingSwiss, German and Canadian research ethics committees (RECs).ParticipantsRCT protocols approved by RECs in 2012 (n=257) and 2016 (n=292).Primary and secondary outcome measuresThe primary outcomes were the proportion of reported SPIRIT items per protocol and the proportion of trial protocols reporting individual SPIRIT items. We compared these outcomes in protocols approved in 2012 and 2016, and built regression models to explore factors associated with adherence to SPIRIT. For each protocol, we also extracted information on general trial characteristics and assessed whether individual SPIRIT items were reportedResultsThe median proportion of reported SPIRIT items among RCT protocols showed a non-significant increase from 72% (IQR, 63%–79%) in 2012 to 77% (IQR, 68%–82%) in 2016. However, in a preplanned subgroup analysis, we detected a significant improvement in investigator-sponsored protocols: the median proportion increased from 64% (IQR, 55%–72%) in 2012 to 76% (IQR, 64%–83%) in 2016, while for industry-sponsored protocols median adherence was 77% (IQR 72%–80%) for both years. The following trial characteristics were independently associated with lower adherence to SPIRIT: single-centre trial, no support from a clinical trials unit or contract research organisation, and investigator-sponsorship.ConclusionsIn 2012, industry-sponsored RCT protocols were reported more comprehensively than investigator-sponsored protocols. After publication of the SPIRIT checklist, investigator-sponsored protocols improved to the level of industry-sponsored protocols, which did not improve.