Author Correction: Nearly all the sky is covered by Lyman-α emission around high-redshift galaxies.

Change history: In this Letter, author M. Akhlaghi should be associated with affiliation (2) rather than (3). This error has been corrected online.

Nearly all the sky is covered by Lyman-α emission around high-redshift galaxies.

Galaxies are surrounded by large reservoirs of gas, mostly hydrogen, that are fed by inflows from the intergalactic medium and by outflows from galactic winds. Absorption-line measurements along the lines of sight to bright and rare background quasars indicate that this circumgalactic medium extends far beyond the starlight seen in galaxies, but very little is known about its spatial distribution. The Lyman-α transition of atomic hydrogen at a wavelength of 121.6 nanometres is an important tracer of warm (about 104 kelvin) gas in and around galaxies, especially at cosmological redshifts greater than about 1.6 at which the spectral line becomes observable from the ground. Tracing cosmic hydrogen through its Lyman-α emission has been a long-standing goal of observational astrophysics1-3, but the extremely low surface brightness of the spatially extended emission is a formidable obstacle. A new window into circumgalactic environments was recently opened by the discovery of ubiquitous extended Lyman-α emission from hydrogen around high-redshift galaxies4,5. Such measurements were previously limited to especially favourable systems6-8 or to the use of massive statistical averaging9,10 because of the faintness of this emission. Here we report observations of low-surface-brightness Lyman-α emission surrounding faint galaxies at redshifts between 3 and 6. We find that the projected sky coverage approaches 100 per cent. The corresponding rate of incidence (the mean number of Lyman-α emitters penetrated by any arbitrary line of sight) is well above unity and similar to the incidence rate of high-column-density absorbers frequently detected in the spectra of distant quasars11-14. This similarity suggests that most circumgalactic atomic hydrogen at these redshifts has now been detected in emission.

Short-term effects of povidone iodine and sodium fluoride therapy on plaque levels and microbiome diversity.

OBJECTIVES: The objective of this study is to evaluate the effect of short-term changes in the oral microbial ecology of dental plaque and plaque levels after topical treatment of a combination of 10% povidone iodine (PI) and 5% sodium fluoride varnish (FV). MATERIALS AND METHODS: A single group design intervention study on 12 pediatric patients, who underwent two baseline plaques samplings before the intervention, were enrolled in the study. A modified mixed dentition Silness-Löe plaque index score was used to assess plaque accumulation and microbial composition was assessed by amplicon sequencing analysis of the 16S rRNA V4 region. RESULTS: Dental plaque accumulation (P = 0.0424) was reduced after 1 week using PI/FV application. This reduction was not observed between the two double-baseline visits. 16S rRNA analysis showed that the single PI/FV therapy did not have dramatic shifts in the plaque microbiome community depicted by hierarchical cluster and principle component analysis. More subtle changes were found when analyzing the Shannon diversity index after the application of PI/FV vs two baselines prior to combination therapy. CONCLUSIONS: The bacteria within the dental biofilms showed resilience in maintaining the overall community diversity but reduced biofilm accumulation following PI/FV therapy. Repeated uses of PI/FV may augment plaque control during dental rehabilitation in children.

The role of black holes in galaxy formation and evolution.

Virtually all massive galaxies, including our own, host central black holes ranging in mass from millions to billions of solar masses. The growth of these black holes releases vast amounts of energy that powers quasars and other weaker active galactic nuclei. A tiny fraction of this energy, if absorbed by the host galaxy, could halt star formation by heating and ejecting ambient gas. A central question in galaxy evolution is the degree to which this process has caused the decline of star formation in large elliptical galaxies, which typically have little cold gas and few young stars, unlike spiral galaxies.

Cardiovascular magnetic resonance feature-tracking assessment of myocardial mechanics: Intervendor agreement and considerations regarding reproducibility.

AIM: To assess intervendor agreement of cardiovascular magnetic resonance feature tracking (CMR-FT) and to study the impact of repeated measures on reproducibility. MATERIALS AND METHODS: Ten healthy volunteers underwent cine imaging in short-axis orientation at rest and with dobutamine stimulation (10 and 20 µg/kg/min). All images were analysed three times using two types of software (TomTec, Unterschleissheim, Germany and Circle, cvi(42), Calgary, Canada) to assess global left ventricular circumferential (Ecc) and radial (Err) strains and torsion. Differences in intra- and interobserver variability within and between software types were assessed based on single and averaged measurements (two and three repetitions with subsequent averaging of results, respectively) as determined by Bland-Altman analysis, intraclass correlation coefficients (ICC), and coefficient of variation (CoV). RESULTS: Myocardial strains and torsion significantly increased on dobutamine stimulation with both types of software (p<0.05). Resting Ecc and torsion as well as Ecc values during dobutamine stimulation were lower measured with Circle (p<0.05). Intra- and interobserver variability between software types was lowest for Ecc (ICC 0.81 [0.63-0.91], 0.87 [0.72-0.94] and CoV 12.47% and 14.3%, respectively) irrespective of the number of analysis repetitions. Err and torsion showed higher variability that markedly improved for torsion with repeated analyses and to a lesser extent for Err. On an intravendor level TomTec showed better reproducibility for Ecc and torsion and Circle for Err. CONCLUSIONS: CMR-FT strain and torsion measurements are subject to considerable intervendor variability, which can be reduced using three analysis repetitions. For both vendors, Ecc qualifies as the most robust parameter with the best agreement, albeit lower Ecc values obtained using Circle, and warrants further investigation of incremental clinical merit.

[Principles of intervertebral disc assessment in private accident insurance]. / Grundlagen der Bandscheibenbegutachtung in der privaten Unfallversicherung (I).

Due to the spread of intervertebral disc degeneration, insurance companies and experts are regularly confronted with related assessments of insured persons under their private accident insurance. These claims pose a particular challenge for experts, since, in addition to the clinical assessment of the facts, extensive knowledge of general accident insurance conditions, case law and current study findings is required. Each case can only be properly assessed through simultaneous consideration of both the medical and legal facts. These guidelines serve as the basis for experts and claims.managers with respect to the appropriate individual factual assessment of intervertebral disc degeneration in private accident insurance.

Real-time phase-contrast flow MRI of haemodynamic changes in the ascending aorta and superior vena cava during Mueller manoeuvre.

AIM: To evaluate the potential of real-time phase-contrast flow magnetic resonance imaging (MRI) at 40 ms resolution for the simultaneous determination of blood flow in the ascending aorta (AA) and superior vena cava (SVC) in response to reduced intrathoracic pressure (Mueller manoeuvre). MATERIALS AND METHODS: Through-plane flow was assessed in 20 healthy young subjects using real-time phase-contrast MRI based on highly undersampled radial fast low-angle shot (FLASH) with image reconstruction by regularized non-linear inversion. Haemodynamic alterations (three repetitions per subject = 60 events) were evaluated during normal breathing (10 s), inhalation with nearly closed epiglottis (10 s), and recovery (20 s). RESULTS: Relative to normal breathing and despite interindividual differences, reduced intrathoracic pressure by at least 30 mmHg significantly decreased the initial peak mean velocity (averaged across the lumen) in the AA by -24 ± 9% and increased the velocity in the SVC by +28 ± 25% (p < 0.0001, n = 23 successful events). Respective changes in flow volume per heartbeat were -25 ± 9% in the AA and +49 ± 44% in the SVC (p < 0.0001, n = 23). Flow parameters returned to baseline during sustained pressure reduction, while the heart rate was elevated by 10% (p < 0.0001) after the start (n = 24) and end (n = 17) of the manoeuvre. CONCLUSIONS: Real-time flow MRI during low intrathoracic pressure non-invasively revealed quantitative haemodynamic adjustments in both the AA and SVC.

Stereotactic radiosurgery for metastatic spine tumors.

Spinal metastases invariably affect the majority of patients with cancer. Many will develop symptoms related to pain and disability from epidural spinal cord compression as well as pathologic fracture of the vertebrae. With the emergence of targeted systemic therapies and a better understanding of cancer biology, patients are living longer with bony metastases. This poses particular challenges, as palliation of pain and maintenance of local tumor control are paramount to quality of life and overall functional independence for these patients. Stereotactic radiosurgery (SRS) has emerged as a potent primary standalone and adjuvant treatment option for spinal metastases. To date, the primary indications for SRS include 1) upfront standalone treatment for painful bony metastases in the oligometastatic patient, 2) standalone or post-operative treatment following progression or recurrence of local disease despite previous conventional external beam radiation therapy (cEBRT), and 3) following surgery during which epidural disease is decompressed and the spine stabilized when indicated. SRS has demonstrated a significant advantage over cEBRT for tumors traditionally regarded as relatively radioresistant such as sarcoma, melanoma, renal cell carcinoma, non-small cell lung cancer and colon carcinoma.9 The radiobiological advantage of increased tumoricidal dose delivery and spinal cord dose sparing in SRS have made this a powerful treatment alternative to cEBRT particularly within the context of re-irradiation. Given the limitations of spinal cord dose constraints, surgery is still the first-line therapy in patients with high-grade epidural spinal cord compression (ESCC). Epidural compression can be treated with SRS, however this risks radiation-induced myelopathy and challenges the safety of effective dose delivery at the dural margin.11 With increasing dose, radiation-induced vertebral fracture is the most serious and prevalent side effect of SRS.53 An overview of SRS, including the most common indications, complications, and outcomes for spinal metastases are presented here.

[Christa Kohler's "communicative psychotherapy" as an integrated psychotherapeutic concept and its biographical, scientific and historical context]. / Christa Kohlers "Kommunikative Psychotherapie"--ein integratives Psychotherapiekonzept im biografischen, wissenschaftlichen und historischen Kontext.

"Communicative psychotherapy" was developed in the 1960s by the East German psychotherapist and psychiatrist Christa Kohler (1928-2004) for the treatment of "neuroses". Similar to established present-day psychotherapeutic methods, such as cognitive behaviour therapy, it combined diverse therapeutic approaches into an integrated treatment programme. This included individual and group therapy, exercise, work and occupational therapy. In contrast to modern psychotherapeutic practice, communicative psychotherapy was based on a firm system of values, namely socialist ideals. According to this system, psychological breakdown was viewed and treated ideologically. In addition, any lack of conformity with the East German system was likewise regarded as a psychopathological deviation, which should be subjected to psychological treatment. The latter concept requires a critical analysis from a current-day perspective. For the first time, this paper concentrates on Kohler's work on neuroses and the theory and practice of her communicative psychotherapy, albeit without neglecting Kohler's other scientific works, her biographical information and her Stasi documents.

Expression of a transgenic T cell receptor beta chain enhances collagen-induced arthritis.

SWR/J transgenic (tg) mice were generated expressing the TCR beta chain derived from an anticollagen type II (CII) arthritogenic T cell clone. The SWR/J strain was selected because it is resistant to collagen-induced arthritis (CIA) and lacks the V beta gene segment used by the T cell clone. Expression of the tg beta chain on all thymocytes and peripheral lymph node T cells led to a more efficient anti-CII immune response, but did not confer CIA susceptibility to SWR/J mice. Nevertheless, this tg beta chain enhanced predisposition to CIA as (DBA/1 x SWR) F1 beta tg mice were more susceptible than normal F1 littermates. Our results demonstrate that the expression of the tg beta chain contributes to CIA susceptibility, but by itself it is not sufficient to overcome CIA resistance in the SWR/J strain.

Organization and evolution of D region class I genes in the mouse major histocompatibility complex.

Chromosome walking has been used to study the organization of the class I genes in the D and Qa regions of the MHC of the BALB/c mouse and in the D region of the AKR mouse. Five and eight class I genes are found in the D and Qa regions of the BALB/c mouse, respectively, while the AKR mouse contains only a single class I D region gene that has been identified by transfection as the Dk gene. Restriction map homologies and crosshybridization experiments suggest that the multiple class I genes in the D region of the BALB/c mouse have been generated by unequal crossing-over involving class I genes from the Qa region. The expanded D region of BALB/c and other H-2d haplotype mouse strains appears to be metastable, since evidence for gene contraction in the Dd region has been found in two mutant strains. Thus the D region and also the Qa region class I genes are in a dynamic state, evolving by gene expansion and contraction.

Allelic exclusion at DNA rearrangement level is required to prevent coexpression of two distinct T cell receptor beta genes.

In mice double transgenic for functionally rearranged T cell receptor (TCR) V beta 2 and V beta 8.2 genes we found that most T lymphocytes express both TCR beta chains simultaneously. These T cells show no abnormality in thymic selection in vivo and their TCRs are capable of transducing activation signals in vitro. These results indicate that multispecific T cells may appear in the periphery if allelic exclusion of TCR beta genes is not established at the level of gene rearrangement.

A correlative analysis of actin filament assembly, structure, and dynamics.

The effect of the type of metal ion (i.e., Ca2+, Mg2+, or none) bound to the high-affinity divalent cation binding site (HAS) of actin on filament assembly, structure, and dynamics was investigated in the absence and presence of the mushroom toxin phalloidin. In agreement with earlier reports, we found the polymerization reaction of G-actin into F-actin filaments to be tightly controlled by the type of divalent cation residing in its HAS. Moreover, novel polymerization data are presented indicating that LD, a dimer unproductive by itself, does incorporate into growing F-actin filaments. This observation suggests that during actin filament formation, in addition to the obligatory nucleation- condensation pathway involving UD, a productive filament dimer, a facultative, LD-based pathway is implicated whose abundance strongly depends on the exact polymerization conditions chosen. The "ragged" and "branched" filaments observed during the early stages of assembly represent a hallmark of LD incorporation and might be key to producing an actin meshwork capable of rapidly assembling and disassembling in highly motile cells. Hence, LD incorporation into growing actin filaments might provide an additional level of regulation of actin cytoskeleton dynamics. Regarding the structure and mechanical properties of the F-actin filament at steady state, no significant correlation with the divalent cation residing in its HAS was found. However, compared to native filaments, phalloidin-stabilized filaments were stiffer and yielded subtle but significant structural changes. Together, our data indicate that whereas the G-actin conformation is tightly controlled by the divalent cation in its HAS, the F-actin conformation appears more robust than this variation. Hence, we conclude that the structure and dynamics of the Mg-F-actin moiety within the thin filament are not significantly modulated by the cyclic Ca2+ release as it occurs in muscle contraction to regulate the actomyosin interaction via troponin.

Genes of the major histocompatibility complex in mouse and man.

The genes of the major histocompatibility complex code for cell-surface molecules that play an important role in the generation of the immune response. These genes and molecules have been studied intensively over the last five decades by geneticists, biochemists, and immunologists, but only recently has the isolation of the genes by molecular biologists facilitated their precise characterization. Many surprising findings have been made concerning their structure, multiplicity, organization, function, and evolution.

A previously undetected MHC gene with an unusual periodic structure.

The major histocompatibility complex is a chromosomal segment embodying several gene clusters among which those with immune functions are the best characterized. This region is suspected to host other as yet undetected genes whose characterization may shed light on the population genetics and evolution of the whole gene complex and thus on its unexplained character of marker locus for a number of diseases of nonimmune or unknown pathogenesis. A novel gene was identified that is transcribed in all tissues tested and is located in mouse and man between the CA and Bf genes of the H-2 and HLA complexes, respectively. From the nucleotide sequence, derived from liver complementary DNA clones, it is predicted that this novel single-copy gene encodes a 42-kilodalton polypeptide that bears no recognizable relation to the protein families known so far, but it displays striking hallmarks of natural selection.

DNA sequence of the gene encoding the E alpha Ia polypeptide of the BALB/c mouse.

A 3.4-kilobase DNA fragment containing the gene coding for the E alpha chain of an Ia (I region-associated) antigen from the BALB/c mouse has been sequenced. It contains at least three exons, which correlate with the major structural domains of the E alpha chain-the two external domains alpha 1 and alpha 2, and the transmembrane-cytoplasmic domain. The coding sequence of the mouse E alpha gene shows striking homology to its counterpart at the DNA and protein levels. The translated alpha 2 exon demonstrates significant similarity to beta 2-microglobulin, to immunoglobulin constant region domains, and to certain domains of transplantation antigens. These observations and those of others suggest that the Ia antigen, transplantation antigen, and immunoglobulin gene families share a common ancestor.

[Cardiac sequelae of hypertension]. / Hypertensive Folgeschäden am Herzen.

Arterial hypertension leads to cardiac restructuring and damage. This "hypertensive heart disease" includes left ventricular hypertrophy. In addition, it is also considered responsible for diastolic and systolic dysfunction, vascular manifestations of microangiopathy and in a broader sense also coronary heart disease as well as cardiac dysrhythmias and sudden cardiac death. The pathophysiological mechanisms depend on a complex neurohumoral regulation and the ensuing change in cardiac structure and output. The initial compensation for increased cardiac demand is followed by permanent heart damage and successive decompensation. At this point the typical complaints involved in cardiac insufficiency or ischemia become evident. Determining the diagnosis is particularly important early on since the prognosis with regard to morbidity and mortality deteriorates if the hypertensive condition persists and the heart develops lasting damage.