[DemStepCare: Risk-stratified support for primary care-based dementia care - evaluation from general practitioner's view]

OBJECTIVE

The innovation fund project DemStepCare aimed to optimize multi-professional care through case management, risk stratification, and crisis outpatient clinic. Here, the evaluation results from the perspective of the general practitioners are presented.

METHODS

A quantitative survey was carried out at three time points regarding acceptance, benefit assessment and sensitivity to dementia of the general practitioners. In addition, qualitative interviews were conducted.

RESULTS

Satisfaction with the overall project was high. Added value and relief factors were perceived and more effective and stable dementia care was achieved through collaboration with case management. Physicians reported increased subjective competence in diagnostics and disease management.

CONCLUSIONS

The results confirm the benefit and effectiveness of DemStepCare from general practitioner's perspective.

[Interinstitutional cooperation between youth welfare services, child and adolescent psychiatry and adult psychiatry - an empirical study]

Family support in Germany is provided by a conglomerate of different support systems. In order to optimize the networking and cooperation of these inter-institutional support systems, it is important to gain a deeper understanding of the existing cooperation structures. Against this background, different qualitative and quantitative aspects were surveyed and analyzed by means of a questionnaire among participants from different help systems. The results point in particular to the currently existing special role of adult psychiatry.

Measurement of polarization observables T, P, and H in π0 and η photoproduction off quasi-free nucleons

The target asymmetry T, recoil asymmetry P, and beam-target double polarization observable H were determined in exclusive π 0 and η photoproduction off quasi-free protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the γ p → π 0 p and γ p → η p reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the η n system at W = 1.68 GeV . A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the S 11 ( 1535 ) and S 11 ( 1650 ) resonances within the S 11 -partial wave.

Combined multidimensional single-cell protein and RNA profiling dissects the cellular and functional heterogeneity of thymic epithelial cells

The network of thymic stromal cells provides essential niches with unique molecular cues controlling T cell development and selection. Recent single-cell RNA sequencing studies have uncovered previously unappreciated transcriptional heterogeneity among thymic epithelial cells (TEC). However, there are only very few cell markers that allow a comparable phenotypic identification of TEC. Here, using massively parallel flow cytometry and machine learning, we deconvoluted known TEC phenotypes into novel subpopulations. Using CITEseq, these phenotypes were related to corresponding TEC subtypes defined by the cells' RNA profiles. This approach allowed the phenotypic identification of perinatal cTEC and their physical localisation within the cortical stromal scaffold. In addition, we demonstrate the dynamic change in the frequency of perinatal cTEC in response to developing thymocytes and reveal their exceptional efficiency in positive selection. Collectively, our study identifies markers that allow for an unprecedented dissection of the thymus stromal complexity, as well as physical isolation of TEC populations and assignment of specific functions to individual TEC subtypes.

Performance of commercial SARS-CoV-2 wild-type and Omicron BA.1 antibody assays compared with pseudovirus neutralization tests

BACKGROUND

Commercially available ELISA-based antibody tests are used to approximate vaccination success against SARS-CoV-2 in at-risk patients, but it is unclear whether they correlate with neutralization of the Omicron variant.

METHODS

269 serum samples of a cohort of 44 non-immunosuppressed participants and 65 MTX-treated rheumatic patients taken before and after COVID-19 booster vaccinations were measured using COVID-19 antibody testing systems with wild-type and Omicron BA.1 antigens developed by three different manufacturers (surrogate virus neutralization test cPass, and binding antibody tests QuantiVac and SeraSpot), as well as with a pseudovirus neutralization test (pVNT). The pVNT was considered the gold standard for determining the presence and level of anti-SARS-CoV-2 antibodies.

RESULTS

All three wild-type ELISAs showed excellent test performance compared with wild-type neutralization in pVNT. However, out of 56 samples without Omicron BA.1 neutralization in pVNT, 71.4% showed positive results in at least one and 28.6% in all three wild-type ELISAs at the manufacturer-defined cut-offs. Omicron ELISAs showed either decreased specificity (57.1% and 55.4% for binding ELISAs) or sensitivity (51.2% in cPass) compared to Omicron neutralization in pVNT. The proportion of any false positive results among all samples decreased from 26.5% before to 3.2% after booster vaccination, however binding antibody test specificities remained below 70%.

CONCLUSIONS

We found a poorer test performance of new Omicron antibody test systems compared to wild-type tests in detecting neutralizing antibodies against the corresponding SARS-CoV-2 variants. Decisions for booster vaccination or passive immunization of at-risk patients should not be based solely on antibody test results.

Embryonic keratin19+ progenitors generate multiple functionally distinct progeny to maintain epithelial diversity in the adult thymus medulla

The thymus medulla is a key site for immunoregulation and tolerance, and its functional specialisation is achieved through the complexity of medullary thymic epithelial cells (mTEC). While the importance of the medulla for thymus function is clear, the production and maintenance of mTEC diversity remains poorly understood. Here, using ontogenetic and inducible fate-mapping approaches, we identify mTEC-restricted progenitors as a cytokeratin19+ (K19+) TEC subset that emerges in the embryonic thymus. Importantly, labelling of a single cohort of K19+ TEC during embryogenesis sustains the production of multiple mTEC subsets into adulthood, including CCL21+ mTEClo, Aire+ mTEChi and thymic tuft cells. We show K19+ progenitors arise prior to the acquisition of multiple mTEC-defining features including RANK and CCL21 and are generated independently of the key mTEC regulator, Relb. In conclusion, we identify and define a multipotent mTEC progenitor that emerges during embryogenesis to support mTEC diversity into adult life.

Course of ankle-brachial-index 12 months after intravascular lithotripsy in calcified peripheral lesions

Background

Intravascular lithotripsy (IVL) is a relatively novel treatment option for calcified lesions in peripheral artery disease. Little is known about the mid to long-term functional status of the patients and target lesion revascularization rate (TLR) after IVL only procedure.

Purpose

To evaluate the course of ankle-brachial-index (ABI) and to assess the rate of revascularization 1 year after intravascular lithotripsy performed on calcified peripheral lesions.

Methods

Between December 2018 and January 2021 IVL was performed on 61 limbs of 51 patients presenting with Rutherford classes 2–5. Ankle-brachial-index (ABI) was documented before the procedure as well as 1 day, 6 months and 1 year after the procedure within a single center real-life registry. Further endpoint was revascularization with PTA or peripheral bypass surgery. The vast majority of cases were done as IVL only procedure (58%) All procedures were done in upper leg/pelvic stenosis.

Results

ABI measurement after 12 months was done in 42 of 51 patients (82%). Three pts were missed due to media sclerosis. Due to loss of follow-up, ABI after 6 months could not be performed on 4/61 patients (7,8%) and 12-month-ABI in another 8/51 cases (15,6%). Initial baseline ABI of 0.6±0.26 before the procedure increased to 0.8±0.25 (p<0.0001) one day afterward. After 6 months, the ABI of 0.8±0.27 (n=49; p<0.0001) was still significantly improved compared to baseline. After 1 year, ABI with 0.7±0.22 was still improved, however not significantly different from baseline (Figure 1). Target lesion revascularization was needed in 7 patients (13%), 4 with subsequent IVL, 3 with PTA and 2 with peripheral bypass surgery.

Conclusions

In our large single center registry, IVL performed mainly as a stand-alone procedure was safe and effective even after a mid-term follow up. TLR was necessary in 13%, which is lower than in previous published IVL data (20,7% as in DISRUPT-PAD-II) [1]. ABI after 12 months improved but did maintain statistical significance, compared with other procedure like scoring balloon [2].

Funding Acknowledgement

Type of funding sources: None.

Dntt expression reveals developmental hierarchy and lineage specification of hematopoietic progenitors

Intrinsic and extrinsic cues determine developmental trajectories of hematopoietic stem cells (HSCs) towards erythroid, myeloid and lymphoid lineages. To dissect early lymphoid specification events, we generated two transgenic mouse models reporting and tracing the expression of terminal deoxynucleotidyl transferase (TdT). Surprisingly, transient induction of TdT was detected on a newly identified multipotent progenitor (MPP) subset which lacked self-renewal capacity but maintained multilineage differentiation potential. TdT induction by MPPs reflected a transcriptionally dynamic but uncommitted stage characterized by low expression of lineage-associated genes. Further, analysis using single-cell CITE-Seq indicated that multipotency is associated with expression of Endothelial Cell-Selective Adhesion Molecule (ESAM). Developmental progression along all lineages is defined by downregulation of ESAM and by stable TdT expression within the lymphoid trajectory. Collectively, we propose a new developmental hierarchy of early hematopoietic progenitors for which we provide their transcriptional profile as well as their phenotypic and functional properties at single cell resolution.

Supported by NIH intramural funding 

FOXN1 forms higher-order nuclear condensates displaced by mutations causing immunodeficiency

The transcription factor FOXN1 is a master regulator of thymic epithelial cell (TEC) development and function. Here, we demonstrate that FOXN1 expression is differentially regulated during organogenesis and participates in multimolecular nuclear condensates essential for the factor’s transcriptional activity. FOXN1’s C-terminal sequence regulates the diffusion velocity within these aggregates and modulates the binding to proximal gene regulatory regions. These dynamics are altered in a patient with a mutant FOXN1 that is modified in its C-terminal sequence. This mutant is transcriptionally inactive and acts as a dominant negative factor displacing wild-type FOXN1 from condensates and causing athymia and severe lymphopenia in heterozygotes. Expression of the mutated mouse ortholog selectively impairs mouse TEC differentiation, revealing a gene dose dependency for individual TEC subtypes. We have therefore identified the cause for a primary immunodeficiency disease and determined the mechanism by which this FOXN1 gain-of-function mutant mediates its dominant negative effect.

Triangle Singularity as the Origin of the a_{1}(1420)

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

"She finds you abhorrent" - The impact of emotional context information on the cortical processing of neutral faces in depression

Depression is associated with abnormalities in patterns of information processing, particularly in the context of processing of interpersonal information. The present study was designed to investigate the differences in depressive individuals in cortical processing of facial stimuli when neutral faces were presented in a context that involved information about emotional valence as well as self-reference. In 21 depressive patients and 20 healthy controls, event-related potentials (ERPs) were recorded during the presentation of neutral facial expressions, which were accompanied by affective context information that was either self- or other-related. Across conditions, depressive patients showed larger mean P100 amplitudes than healthy controls. Furthermore, mean late positive potential (LPP) amplitudes of depressive patients were larger in response to faces in self-related than in other-related context. In addition, irrespective of self-reference, mean LPP responses of depressive patients to faces presented after socially threatening sentences were larger compared with faces presented after neutral sentences. Results regarding self-reference supported results of previous studies indicating larger mean amplitudes in self-related conditions. Findings suggest a general heightened initial responsiveness to emotional cues and a sustained emotion processing of socially threatening information in depressive patients.

Measurement of the helicity asymmetry E for the reaction γ p → π 0 p : The CBELSA/TAPS Collaboration

A measurement of the double-polarization observable E for the reaction γ p → π 0 p is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C4 H9 OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range fromE γ = 600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.

HIV DNA reservoir and elevated PD-1 expression of CD4 T-cell subsets particularly persist in the terminal ileum of HIV-positive patients despite cART

OBJECTIVES

Despite its importance as an HIV anatomic sanctuary, little is known about the characteristics of the HIV reservoir in the terminal ileum (TI). In blood, the immune checkpoint inhibitor programmed-death-1 (PD-1) has been linked to the HIV reservoir and T-cell immune dysfunction. We thus evaluated PD-1 expression and cell-associated HIV DNA in memory CD4 T-cell subsets from TI, peripheral blood (PB) and rectum (RE) of untreated and treated HIV-positive patients to identify associations between PD-1 and HIV reservoir in other sites.

METHODS

Using mononuclear cells from PB, TI and RE of untreated HIV-positive (N = 6), treated (n = 18) HIV-positive and uninfected individuals (n = 16), we identified and sorted distinct memory CD4 T-cell subsets by flow cytometry, quantified their cell-associated HIV DNA using quantitative PCR and assessed PD-1 expression levels using geometric mean fluorescence intensity. Combined HIV-1 RNA in situ hybridization and immunohistochemistry was performed on ileal biopsy sections.

RESULTS

Combined antiretroviral therapy (cART)-treated patients with undetectable HIV RNA and significantly lower levels of HIV DNA in PB showed particularly high PD-1 expression in PB and TI, and high HIV DNA levels in TI, irrespective of clinical characteristics. By contrast, in treatment-naïve patients HIV DNA levels in memory CD4 T-cell subsets were high in PB and TI.

CONCLUSION

Elevated PD-1 expression on memory CD4 T-cells in PB and TI despite treatment points to continuous immune dysfunction and underlines the importance of evaluating immunotherapy in reversing HIV latency and T-cell reconstitution. As HIV DNA particularly persists in TI despite cART, investigating samples from TI is crucial in understanding HIV immunopathogenesis.

[Prevalence of SARS-CoV-2 in children from a cohort of 2192 patients]

Hintergrund

In Deutschland sind aktuell (Stand 18.06.2020) 187.764 SARS-CoV-2-Infektionen gemeldet. 6,9 % der Infizierten sind dabei unter 19 Jahre. Es gibt erste Hinweise darauf, dass Kinder häufig asymptomatisch sind und einen milderen Verlauf zeigen.

Ziel der Arbeit

Ziel dieser Arbeit war es, eine Aussage bezüglich der Infektionsprävalenz in dieser speziellen Patientengruppe zu ermöglichen.

Material und Methoden

Im Rahmen der SARS-CoV-2-Pandemie wurden zwischen dem 13.03.2020 und dem 18.06.2020 alle Kinder und Jugendlichen, welche entweder zum Ausschluss einer SARS-CoV-2-Infektion oder als Verdachtsfall einen Abstrich auf SARS-CoV‑2 erhielten, erfasst. Die Daten wurden auf standardisierten Anamnesebogen gesammelt und retrospektiv anonymisiert ausgewertet.

Ergebnisse

In dem Zeitraum wurden 2192 Kinder und Jugendliche auf SARS-CoV‑2 abgestrichen. 37 Patienten wurden positiv getestet (1,7 %). 36/37 waren Verdachtsfälle, und 28/37 waren symptomatisch. Führende Symptome waren trockener Husten, Schnupfen und Fieber. Drei Kinder mussten stationär betreut werden. Keines zeigte einen schweren Verlauf. Unter den Getesteten waren 505 Patienten, die aufgrund ihrer chronischen Grunderkrankung als Risikopatienten eingestuft wurden, von denen 3 (0,6 %) einen positiven Nachweis mit asymptomatischem bzw. mildem Verlauf hatten.

Schlussfolgerung

Hiermit können die ersten Daten bestätigt werden, wonach Kinder und Jugendliche häufig asymptomatische oder klinisch milde Infektions- bzw. Erkrankungsverläufe zeigen. Zudem fanden wir keinen Hinweis für eine hohe Dunkelziffer für SARS-CoV-2-Infektionen in dieser regionalen pädiatrischen Kohorte.

Observation of the pη^{'} Cusp in the New Precise Beam Asymmetry Σ Data for γp→pη

Data on the beam asymmetry Σ in the photoproduction of η mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from W=1748  MeV to W=2045  MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the pη^{'} threshold [E_{γ}=1447  MeV (W=1896  MeV)]. The latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the N(1895)1/2^{-} nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.

A cavity optomechanical locking scheme based on the optical spring effect

We present a novel locking scheme for active length-stabilization and frequency detuning of a cavity optomechanical device based on the optical spring effect. The error signal is generated by utilizing the position measurement of a thermally driven intra-cavity nanomechanical device and employing its detuning-dependent frequency shift caused by the dispersive coupling to the cavity field. The scheme neither requires external modulation of the laser or the cavity nor does it demand for additional error signal readout, rendering its technical implementation rather simple for a large variety of existing optomechanical devices. Specifically, for large-linewidth microcavities or in situations where other locking schemes appear unfavorable conceptually or are hard to realize technically, the optical spring lock represents a potential alternative for stabilizing the cavity length. We explain the functional principle of the lock and characterize its performance in terms of bandwidth and gain profile.

Precision measurement of the neutral pion lifetime

The explicit breaking of the axial symmetry by quantum fluctuations gives rise to the so-called axial anomaly. This phenomenon is solely responsible for the decay of the neutral pion π⁰ into two photons (γγ), leading to its unusually short lifetime. We precisely measured the decay width Γ of the [Formula: see text] process. The differential cross sections for π⁰ photoproduction at forward angles were measured on two targets, carbon-12 and silicon-28, yielding [Formula: see text], where stat. denotes the statistical uncertainty and syst. the systematic uncertainty. We combined the results of this and an earlier experiment to generate a weighted average of [Formula: see text] Our final result has a total uncertainty of 1.50% and confirms the prediction based on the chiral anomaly in quantum chromodynamics.

Cardiac reactions to emotional words in adolescents and young adults with PTSD after child abuse

Post-traumatic stress disorder (PTSD) is associated with alterations in cardiac reactivity to threat cues. Meta-analyses have summarized that adults with PTSD have increased heart rates in response to trauma-related stimuli. However, the opposite effect (i.e., cardiac hyporeactivity) has recently been reported in subgroups of PTSD patients. In children and adolescents with PTSD, reports of cardiac alterations are rare and ambiguous. So far, most studies in adolescents and young adults are restricted to victims of accidents, even though PTSD is highly prevalent in victims of child maltreatment. The present study aimed at investigating cardiac reactions in adolescents and young adults with PTSD after child abuse. Cardiac responses to standardized emotional words were studied in 39 adolescent and young adult PTSD patients after childhood sexual and/or physical abuse as compared to 39 healthy control subjects (age range: 15-20 years). The experimental paradigm consisted of a passive reading task with neutral, positive, physically threatening, and socially threatening (swear) words. Results showed that cardiac reactions to negative stimuli, particularly physically threatening stimuli, were less pronounced in PTSD patients than in controls. Moreover, cardiac reactions in response to socially threatening words were less variable in the PTSD group. No differences between and within groups were present in reaction to neutral or positive stimuli. Findings suggest that a physiologically blunted subtype of PTSD may already manifest during adolescence and young adulthood. Moreover, the results of the present study emphasize the relevance of individual trauma history for physiological reactions.

Processing of affective words in adolescent PTSD-Attentional bias toward social threat

Post-traumatic stress disorder (PTSD) is associated with a hypersensitivity to potential threat. This hypersensitivity manifests through differential patterns of emotional information processing and has been demonstrated in behavioral and neurophysiological experimental paradigms. However, the majority of research has been focused on adult patients with PTSD. To examine possible differences in underlying neurophysiological patterns for adolescent patients with PTSD after childhood sexual and/or physical abuse (CSA/CPA), ERP correlates of emotional word processing in 38 healthy participants and 40 adolescent participants with PTSD after experiencing CSA/CPA were studied. The experimental paradigm consisted of a passive reading task with neutral, positive (e.g., paradise), physically threatening (e.g., torment), and socially threatening (i.e., swearing, e.g., son of a bitch) words. A modulation of P3 amplitudes by emotional valence was found, with positive words inducing less elevated amplitudes over both groups. Interestingly, in later processing, the PTSD group showed augmented early late positive potential (LPP) amplitudes for socially threatening stimuli, while there were no modulations within the healthy control group. Also, region-specific emotional modulations for anterior and posterior electrode clusters were found. For the anterior LPP, highest activations have been found for positive words, while socially and physically threatening words led to strongest modulations in the posterior LPP cluster. There were no modulations by group or emotional valence at the P1 and EPN stage. The findings suggest an enhanced conscious processing of socially threatening words in adolescent patients with PTSD after CSA/CPA, pointing to the importance of a disjoined examination of threat words in emotional processing research.

[Primary cutaneous lymphoma-a case series of 163 patients]

BACKGROUND

In addition to a broad and clinically diverse spectrum of known primary cutaneous lymphomas, for which an incidence of 1-3:100,000 is postulated, each year further entities are specified and defined. The goal is the presentation of a case series from daily clinical routine.

METHODS

Over a period of 6 years and 2 months, patients consulting the Department of Dermatology, Medical Center University of Freiburg, were registered. Subsequently, collectives of mycosis fungoides (MF), Sezary syndrome (SS), CD30+ lymphoproliferative diseases, single cases with rare primary cutaneous lymphomas, and subcollectives of B‑cell lymphomas were examined. The high number of MF cases allowed the additional quantitative analyses of the types of therapies used in this group.

RESULTS

Yearly 16-25 new diagnoses of primary cutaneous lymphoma are made. The evaluation of 163 primary cutaneous lymphoma revealed 111 cases with MF (68.1%), including 9 particular variants, 15 primary cutaneous CD30+ lymphoproliferative diseases (9.2%) dominated by 10 lymphomatoid papulosis (LyP), in addition to 5 primary cutaneous anaplastic large cell lymphoma (PCALCL), 6 SS (3.68%), and 24 cutaneous B‑cell lymphomas (14-72%). Three cases with rare primary cutaneous T/NK cell lymphomas are addressed in detail. In all, 82% of MF cases were stage IA and IB. The descending use of therapies for stage I-III included steroids and diverse UV therapies followed by bexarotene, interferon-α, methotrexate, and extracorporal photophoresis.

CONCLUSIONS

Diagnoses of cutaneous lymphomas belong to a vast spectrum of differential diagnoses. This registry describes frequent findings and shows rare variants. You can only diagnose what you know; accordingly, a collection of case reports, which we wish to encourage, can help in processing and specification of entities.

Strain-dependent effects on lung structure, matrix remodeling, and Stat3/Smad2 signaling in C57BL/6N and C57BL/6J mice after neonatal hyperoxia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants, characterized by lung growth arrest and matrix remodeling. Various animal models provide mechanistic insights in the pathogenesis of BPD. Since there is increasing evidence that genetic susceptibility modifies the response to lung injury, we investigated strain-dependent effects in hyperoxia (HYX)-induced lung injury of newborn mice. To this end, we exposed newborn C57BL/6N and C57BL/6J mice to 85% O₂ (HYX) or normoxia (NOX; 21% O₂) for 28 days, followed by lung excision for histological and molecular measurements. BL/6J-NOX mice exhibited a lower body and lung weight than BL/6N-NOX mice; hyperoxia reduced body weight in both strains and increased lung weight only in BL/6J-HYX mice. Quantitative histomorphometric analyses revealed reduced alveolar formation in lungs of both strains after HYX, but the effect was greater in BL/6J-HYX mice than BL/6N-HYX mice. Septal thickness was lower in BL/6J-NOX mice than BL/6N-NOX mice but increased in both strains after HYX. Elastic fiber density was significantly greater in BL/6J-HYX mice than BL/6N-HYX mice. Lungs of BL/6J-HYX mice were protected from changes in gene expression of fibrillin-1, fibrillin-2, fibulin-4, fibulin-5, and surfactant proteins seen in BL/6N-HYX mice. Finally, Stat3 was activated by HYX in both strains; in contrast, activation of Smad2 was markedly greater in lungs of BL/6N mice than BL/6J mice after HYX. In summary, we demonstrate strain-dependent differences in lung structure and matrix, alveolar epithelial cell markers, and Smad2 (transforming growth factor β) signaling in neonatal HYX-induced lung injury. Strain-dependent effects and genetic susceptibility need be taken into consideration for reproducibility and reliability of results in animal models.

The transcription factor Duxbl mediates elimination of pre-T cells that fail β-selection

During β-selection, T cells without productive TCRβ rearrangements are eliminated. Klein et al. show that the transcription factor Duxbl regulates this process by inducing apoptosis through activation of the Oas/RNaseL pathway. Successful TCRβ rearrangement rescues cells by pre-TCR–mediated Duxbl suppression.

T cell development is critically dependent on successful rearrangement of antigen-receptor chains. At the β-selection checkpoint, only cells with a functional rearrangement continue in development. However, how nonselected T cells proceed in their dead-end fate is not clear. We identified low CD27 expression to mark pre-T cells that have failed to rearrange their β-chain. Expression profiling and single-cell transcriptome clustering identified a developmental trajectory through β-selection and revealed specific expression of the transcription factor Duxbl at a stage of high recombination activity before β-selection. Conditional transgenic expression of Duxbl resulted in a developmental block at the DN3-to-DN4 transition due to reduced proliferation and enhanced apoptosis, whereas RNA silencing of Duxbl led to a decrease in apoptosis. Transcriptome analysis linked Duxbl to elevated expression of the apoptosis-inducing Oas/RNaseL pathway. RNaseL deficiency or sustained Bcl2 expression led to a partial rescue of cells in Duxbl transgenic mice. These findings identify Duxbl as a regulator of β-selection by inducing apoptosis in cells with a nonfunctional rearrangement.