Emergence of coherence in the charge-density wave state of 2H-NbSe2

A charge-density wave (CDW) state has a broken symmetry described by a complex order parameter with an amplitude and a phase. The conventional view, based on clean, weak-coupling systems, is that a finite amplitude and long-range phase coherence set in simultaneously at the CDW transition temperature T_cdw. Here we investigate, using photoemission, X-ray scattering and scanning tunnelling microscopy, the canonical CDW compound 2H-NbSe₂ intercalated with Mn and Co, and show that the conventional view is untenable. We find that, either at high temperature or at large intercalation, CDW order becomes short-ranged with a well-defined amplitude, which has impacts on the electronic dispersion, giving rise to an energy gap. The phase transition at T_cdw marks the onset of long-range order with global phase coherence, leading to sharp electronic excitations. Our observations emphasize the importance of phase fluctuations in strongly coupled CDW systems and provide insights into the significance of phase incoherence in ‘pseudogap’ states.

Charge density waves are described by a complex order parameter whose amplitude is expected to vanish at the transition temperature. This study shows that the transition in 2H-NbSe₂ is driven by fluctuations of the phase of the order parameter, with a finite amplitude surviving in the disordered state.

MS susceptibility is not affected by single nucleotide polymorphisms in the MMP9 gene

Matrix metalloproteinase 9 (MMP9) plays an important role in the pathogenesis of multiple sclerosis (MS). However, the impact of genetic variants affecting MMP9 on MS susceptibility is still in debate. We could not detect an association of MMP9 SNPs with MS on a genome-wide significance level by SNP genotyping, followed by imputation of SNPs within a region stretching 2Mbp up- and down-stream of MMP9. Rs6073751, located within WFDC2, was found associated with MS most strongly. Rs3918242, associated with MS according to previous reports, showed nominal significance only. Meta-analysis of our own and published data did not confirm this effect.

Cytotoxic activities of hydroxyethyl piperazine-based σ receptor ligands on cancer cells alone and in combination with melphalan, PB28 and haloperidol

σ Receptor ligands are attracting interest as possible anti-cancer agents because of their ability to induce cell death by different mechanisms. In this study we investigated the cytotoxic effects of 12 recently developed σ-receptor ligands in a panel of eight different human tumor cell lines by either the crystal violet or MTT assays. The results show that σ ligands have broad cytotoxic activity on a number of human cancer cell lines with IC50 values in the low μM range. In addition, apoptosis was observed by the annexin-V/PI double staining method when RPMI 8226 human multiple myeloma cells were treated with a representative σ ligand, (R)-2b. Combination of (R)-2b with melphalan led to a higher apoptotic rate than with the drug alone. Likewise, combined treatment of (R)-2b with the known high affinity σ2-agonist PB28 showed an additive effect on the induction of apoptosis in the RPMI 8226 line. In contrast, combinations of (R)-2b with the known σ1-antagonist haloperidol lead to a significant reduction in the cytotoxic activity of (R)-2b. These results support the idea that (R)-2b acts as a σ-agonist to cause the death of RPMI 8226 cells.

Interferon β-1a reduces increased interleukin-16 levels in multiple sclerosis patients

OBJECTIVES

There is convergent evidence for an important role of interleukin-16 (IL-16) in the pathogenesis of multiple sclerosis (MS). IL-16 serves as a chemoattractant for different immune cells that are involved in developing lesions. Here, we compared IL-16 levels of MS patients and controls and addressed the long-term effect of IFN-β, the most common immunomodulatory MS therapy, on IL-16 serum levels in MS patients over 2 years. Beyond this, we analysed the expression of IL-16 in two CD4(+) T-cell subsets, Th1 and Th17 cells, which are important autoimmune mediators and affected by IFN-β treatment, derived from myelin-specific T-cell transgenic mice.

MATERIALS AND METHODS

IL-16 serum levels of 17 controls and of 16 MS patients before therapy and at months 1, 2, 3, 6, 9, 12 and 24 during IFN-β1a therapy were determined by ELISA. MRI was performed before therapy, at months 12 and 24. IL-16 expression of in vitro differentiated murine myelin oligodendrocyte glycoprotein (MOG)-specific Th1 and Th17 cells was quantified by real-time PCR.

RESULTS

Before therapy, MS patients showed significantly elevated IL-16 levels compared with controls irrespective of disease activity determined by MRI. Therapy with IFN-β1a led to a significant linear decrease in IL-16 serum levels beginning after 2 months. MOG-specific Th17 cells expressed more IL-16 than Th1 cells.

CONCLUSIONS

Reduction in increased IL-16 levels may be of relevance for the therapeutic effect of IFN-β1a in MS. Easily accessible IL-16 serum levels hold a potential as biomarker of treatment efficacy in MS.

Antiviral Innate Immunity: Introduction☆

The concept of ‘innate immunity’ embraces all sorts of measures that exclude, inhibit, or slow down infections with little specificity and without adaptation or generation of a long-lasting memory. The mammalian innate immune defenses described in this article comprise defensins, the complement system, nonspecific phagocytic and cytolytic leukocytes (macrophages, monocytes, granulocytes, natural killer cells, and dendritic cells), and cytokines such as the antivirally active interferons. Since the type I interferon (IFN-α/β) system is our primary defense against viral infections, special attention will be paid to the virus-triggered induction of IFN transcription, the signaling activated by IFNs, and the antiviral factors expressed as a consequence

First cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infections in France, investigations and implications for the prevention of human-to-human transmission, France, May 2013

In May 2013, Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection was diagnosed in an adult male in France with severe respiratory illness, who had travelled to the United Arab Emirates before symptom onset. Contact tracing identified a secondary case in a patient hospitalised in the same hospital room. No other cases of MERS-CoV infection were identified among the index case’s 123 contacts, nor among 39 contacts of the secondary case, during the 10-day follow-up period.

Claudin-7 expression in hepatocellular carcinoma

BACKGROUND

The importance of adhesion molecules for local invasion by neoplastic cells and development of metastasis has been confirmed by numerous studies over the past decade. Claudins are integral parts of tight junctions. The aim of the present study was to examine the significance of the expression of claudin-7 messenger RNA (mRNA) as a prognostic factor for hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

We examined liver tumor and nontumor tissues from 20 HCC patients who underwent resection or liver transplantation.

RESULTS

A significant increase in the expression of claudin-7 was observed in tumor versus nontumor tissues. There was no significant correlation between the expression profile of claudin-7 mRNA and patient demographic data, the presence of cirrhosis, or the histological stage of tumor differentiation or vascular invasion. Survival analysis showed a trend toward a better prognosis among patients with overexpression of claudin-7 in tumor tissues.

Determination of the optimal length of insertion of central venous catheters in pediatric patients by endovascular ECG

BACKGROUND

In children the position of the tip of central venous catheters (CVC) is most often examined by chest radiography. Endovascular electrocardiography (ECG), using the CVC as an electrode, permits the correct placement of a CVC without the need for a chest X-ray. The use of a commercialised endovascular ECG-system (Alphacard®) for CVC-placement was evaluated in pediatric patients.

METHODS

ECG-guidance was prospectively applied in 50 children (0-17 years, stratified into 5 age related subgroups). Positioning of the CVC was performed under ECG-guidance and subsequently assessed by chest X-ray. The frequency of correct ECG-guided CVC-placement in one single attempt, duration until confirmation by ECG and X-ray, and body weight-related depth of CVC-insertion were assessed.

RESULTS

In 44 patients ECG-guidance resulted in a correct placement of the CVC-tip. Duration (median and [IQR] in sec.) to confirmation of correct placement was shorter with the ECG method (78[49-136]) than with X-ray (720[249-1095]) (P<0.0001). In five patients the ECG method failed because the CVC chosen was too short or the anesthetist did not trust the ECG-method. In one patient an unknown anatomical anomaly was present. Depth of insertion of the CVC was positively correlated with body weight (r2 0.68, P<0.0001). Stratification for age had no impact on duration until confirmation of CVC-position. No complications occurred during CVC-placement.

CONCLUSION

ECG guidance of CVC-placement in children is a reliable technique, preventing children and health care providers from unnecessary X-ray exposure. Depending on local infrastructure and protocols it can furthermore shorten the procedure of CVC placement.

A web-based tool for personalized prediction of long-term disease course in patients with multiple sclerosis

BACKGROUND AND PURPOSE

The Evidence-Based Decision Support Tool in Multiple Sclerosis (EBDiMS) is the first web-based prognostic calculator in multiple sclerosis (MS) capable of delivering individualized estimates of disease progression. It has recently been extended to provide long-term predictions based on the data from a large natural history cohort.

METHODS

We compared the predictive accuracy and consistency of EBDiMS with that of 17 neurologists highly specialized in MS.

RESULTS

We show that whilst the predictive accuracy was similar, neurologists showed a significant intra-rater and inter-rater variability.

CONCLUSIONS

Because EBDiMS was consistent, it is of superior utility in a specialist setting. Further field testing of EBDiMS in non-specialist settings, and investigation of its usefulness for counselling patients in treatment decisions, is warranted.

Cerebrospinal fluid parameters of B cell-related activity in patients with active disease during natalizumab therapy

Recently, the disappearance of oligoclonal bands (OCBs) from the cerebrospinal fluid (CSF) of a few natalizumab-treated patients with multiple sclerosis (MS) has been reported. This is interesting since CSF-restricted OCB are believed to persist in MS. We pooled CSF data from 14 MS centers to obtain an adequate sample size for investigating the suspected changes in central nervous system (CNS)-restricted humoral immune activities in the context of natalizumab therapy. In a retrospective chart analysis, CSF parameters of blood-CSF barrier integrity and intrathecal IgG production from 73 natalizumab-treated MS patients requiring a diagnostic puncture for exclusion of progressive multifocal leukoencephalopathy were compared with CSF data obtained earlier in the course of disease before natalizumab therapy. At the time of repeat lumbar puncture, local IgG production (according to Reibergram) was significantly reduced (p < 0.0001) and OCB had disappeared in 16% of the patients. We therefore conclude that natalizumab therapy interferes with intrathecal antibody production at least in a significant number of patients.

Electron-phonon coupling in the conventional superconductor YNi2B2C at high phonon energies studied by time-of-flight neutron spectroscopy

We report an inelastic neutron scattering investigation of phonons with energies up to 159 meV in the conventional superconductor YNi(2)B(2)C. Using the sweep mode, a newly developed time-of-flight technique involving the continuous rotation of a single crystal specimen, allowed us to measure a four-dimensional volume in (Q, E) space and, thus, determine the dispersion surface and linewidths of the A(1g) (≈102 meV) and A(u) (≈159 meV) type phonon modes over the whole Brillouin zone. Despite of having linewidths of Γ=10 meV, A(1g) modes do not strongly contribute to the total electron-phonon coupling constant λ. However, experimental linewidths show a remarkable agreement with ab initio calculations over the complete phonon energy range, demonstrating the accuracy of such calculations in a rare comparison to a comprehensive experimental data set.