The first wave of pandemic influenza (H1N1) 2009 in Germany: From initiation to acceleration

Background  

The first imported case of pandemic influenza (H1N1) 2009 in Germany was confirmed in April 2009. However, the first wave with measurable burden of disease started only in October 2009. The basic epidemiological and clinical characteristics of the pandemic were analysed in order to understand the course of the pandemic in Germany.     

The turnover of synovial T cells is higher than in T cells in the peripheral blood in persistent oligoarticular juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) summarizes a group of inflammatory diseases of childhood. The etiology remains still unclear. In JIA, T cells have been demonstrated to play key roles in the pathogenesis. T-cell proliferation in JIA may be different in the peripheral blood (PB) and the synovial fluid (SF). The aim of this study is to demonstrate the turnover of T cells in the PB and SF of patients with persistent oligoarticular JIA (oJIA) compared to controls. Matched pairs of samples were investigated derived from PB and SF of nine patients with persistent oJIA. The cells from PB and SF were determined by flow cytometry. The majority of the PBMC and IAMC were in phase G0/G1, with fewer than 1% in S phase. In the SF, the percentage of cells in the S phase are higher than in the PB. The percentage of cells in the S phase in SF are equal to the result in the control group. In conclusion, the turnover of synovial T cells in persistent oJIA is higher than in the PB.     

A comparison of univariate,vector, bilinear autoregressive,and band power features for brain–computer interfaces

Selecting suitable feature types is crucial to obtain good overall brain–computer interface performance. Popular feature types include logarithmic band power (logBP), autoregressive (AR) parameters, time-domain parameters, and wavelet-based methods. In this study, we focused on different variants of AR models and compare performance with logBP features. In particular, we analyzed univariate, vector, and bilinear AR models. We used four-class motor imagery data from nine healthy users over two sessions. We used the first session to optimize parameters such as model order and frequency bands. We then evaluated optimized feature extraction methods on the unseen second session. We found that band power yields significantly higher classification accuracies than AR methods. However, we did not update the bias of the classifiers for the second session in our analysis procedure. When updating the bias at the beginning of a new session, we found no significant differences between all methods anymore. Furthermore, our results indicate that subject-specific optimization is not better than globally optimized parameters. The comparison within the AR methods showed that the vector model is significantly better than both univariate and bilinear variants. Finally, adding the prediction error variance to the feature space significantly improved classification results.     

Optimized stimulus presentation patterns for an event-related potential EEG-based brain–computer interface

P300 brain–computer interface (BCI) systems typically use a row/column (RC) approach. This article presents a P300 BCI based on a 12 × 7 matrix and new paradigmatic approaches to flashing characters designed to decrease the number of flashes needed to identify a target character. Using an RC presentation, a 12 × 7 matrix requires 19 flashes to present all items twice (12 columns and seven rows) per trial. A 12 × 7 matrix contains 84 elements (characters). To identify a target character in 12 × 7 matrix using the RC pattern, 19 flashes (sub-trials) are necessary. In each flash, the selected characters (one column or one row in the RC pattern) are flashing. We present four new paradigms and compare the performance to the RC paradigm. These paradigms present quasi-random groups of characters using 9, 12, 14 and 16 flashes per trial to identify a target character. The 12-, 14- and 16-flash patterns were optimized so that the same character never flashed twice in succession. We assessed the practical bit rate and classification accuracy of the 9-, 12-, 14-, 16- and RC (19-flash) pattern conditions in an online experiment and with offline simulations. The results indicate that 16-flash pattern is better than other patterns and performance of an online P300 BCI can be significantly improved by selecting the best presentation paradigm for each subject.     

Post-thymic regulation of CD5 levels in human memory T cells is inversely associated with the strength of responsiveness to interleukin-15

Immunologic memory is a critical feature of the adaptive immune system to fight recurrent infections. However, the mechanisms that shape the composition and function of the human memory T-cell pool remain incompletely understood. We here demonstrate that post-thymic human T-cell differentiation was associated with the downregulation, but not loss, of the inhibitory molecule CD5. The sensitivity of human CD8(+) and CD4(+) memory T cells to interleukin (IL)-15 was inversely associated with the level of CD5 expression. CD5 expression was downregulated by IL-15-mediated signaling in vitro and CD5(lo) memory T cells accumulated in the bone marrow. Persistent antigenic stimulation, as in the case of cytomegalovirus infection and rheumatoid arthritis (RA), was also associated with an increased number of CD5(lo) memory T cells. In conclusion, CD5 may be a useful marker to identify memory T-cell subsets with distinct responsiveness to the homeostatic cytokine IL-15.     

A Duffy antigen receptor for chemokines (DARC) polymorphism that determines pro-fibrotic chemokine serum concentrations is not directly associated with severity of hepatitis C infection

Genetic host factors influence the progression of hepatitis C infection (HCV). Chemokines play important roles in HCV-induced liver fibrosis. Recently, a single nucleotide polymorphism in the Duffy antigen receptor for chemokines (DARC) was identified which strongly determines the serum concentrations of pivotal pro-fibrotic chemokines, including CCL2. We here tested the hypothesis that this genetic variant (rs12075 A/G) is a risk factor for liver fibrosis in HCV infection. Overall, 880 patients with HCV from three cohorts and 108 controls were genotyped for rs12075. Although serum CCL2 levels were associated with early liver fibrosis, rs12075 itself was not associated with HCV infection or the severity of liver disease in any of the cohorts. The lack of association was evident in qualitative and quantitative analysis despite sufficient statistical power. We conclude that gene variations that strongly determine serum concentrations of chemokines are not necessarily risk markers of the disease traits in which these molecules play pathophysiological roles.     

CR1 genotype is associated with entorhinal cortex volume in young healthy adults

Gene-brain structure associations of 3 recently discovered risk genes for Alzheimer's disease, CLU (rs11136000C>T), CR1 (rs6656401G>A), and PICALM (rs3851179G>A), were investigated in 2 independent cohorts of young healthy adults (n = 430 and n = 492, respectively). We assessed structural differences in 2 core structures of Alzheimer pathology, entorhinal cortex and hippocampus, by voxel-based morphometry using high-resolution magnetic resonance imaging (MRI) data. For CLU and PICALM no significant genotype-related differences in local gray matter volume were found. CR1 risk allele (A) carriers showed smaller local gray matter volume in the entorhinal cortex, as confirmed in both cohorts. This association, apparent in young healthy adults, might mediate susceptibility for Alzheimer's disease later in life.