Arne C. Bathke

Neutrophil extracellular trap (NET) formation characterises stable and exacerbated COPD and correlates with airflow limitation

BackgroundCOPD is a progressive disease of the airways that is characterized by neutrophilic inflammation, a condition known to promote the excessive formation of neutrophil extracellular traps (NETs). The presence of large amounts of NETs has recently been demonstrated for a variety of inflammatory lung diseases including cystic fibrosis, asthma and exacerbated COPD.ObjectiveWe test whether excessive NET generation is restricted to exacerbation of COPD or whether it also occurs during stable periods of the disease, and whether NET presence and amount correlates with the severity of airflow limitation.Patients, materials and methodsSputum samples from four study groups were examined: COPD patients during acute exacerbation, patients with stable disease, and smoking and non-smoking controls without airflow limitation. Sputum induction followed the ECLIPSE protocol. Confocal laser microscopy (CLSM) and electron microscopy were used to analyse samples. Immunolabelling and fluorescent DNA staining were applied to trace NETs and related marker proteins. CLSM specimens served for quantitative evaluation.ResultsSputum of COPD patients is clearly characterised by NETs and NET-forming neutrophils. The presence of large amounts of NET is associated with disease severity (p < 0.001): over 90 % in exacerbated COPD, 45 % in stable COPD, and 25 % in smoking controls, but less than 5 % in non-smokers. Quantification of NET-covered areas in sputum preparations confirms these results.ConclusionsNET formation is not confined to exacerbation but also present in stable COPD and correlates with the severity of airflow limitation. We infer that NETs are a major contributor to chronic inflammatory and lung tissue damage in COPD.

High-frequency oscillations in epilepsy and surgical outcome. A meta-analysis

High frequency oscillations (HFOs) are estimated as a potential marker for epileptogenicity. Current research strives for valid evidence that these HFOs could aid the delineation of the to-be resected area in patients with refractory epilepsy and improve surgical outcomes. In the present meta-analysis, we evaluated the relation between resection of regions from which HFOs can be detected and outcome after epilepsy surgery. We conducted a systematic review of all studies that related the resection of HFO-generating areas to postsurgical outcome. We related the outcome (seizure freedom) to resection ratio, that is, the ratio between the number of channels on which HFOs were detected and, among these, the number of channels that were inside the resected area. We compared the resection ratio between seizure free and not seizure free patients. In total, 11 studies were included. In 10 studies, ripples (80–200 Hz) were analyzed, and in 7 studies, fast ripples (>200 Hz) were studied. We found comparable differences (dif) and largely overlapping confidence intervals (CI) in resection ratios between outcome groups for ripples (dif = 0.18; CI: 0.10–0.27) and fast ripples (dif = 0.17; CI: 0.01–0.33). Subgroup analysis showed that automated detection (dif = 0.22; CI: 0.03–0.41) was comparable to visual detection (dif = 0.17; CI: 0.08–0.27). Considering frequency of HFOs (dif = 0.24; CI: 0.09–0.38) was related more strongly to outcome than considering each electrode that was showing HFOs (dif = 0.15; CI = 0.03–0.27). The effect sizes found in the meta-analysis are small but significant. Automated detection and application of a detection threshold in order to detect channels with a frequent occurrence of HFOs is important to yield a marker that could be useful in presurgical evaluation. In order to compare studies with different methodological approaches, detailed and standardized reporting is warranted.

Transcriptional profiling differences for articular cartilage and repair tissue in equine joint surface lesions

BackgroundFull-thickness articular cartilage lesions that reach to the subchondral bone yet are restricted to the chondral compartment usually fill with a fibrocartilage-like repair tissue which is structurally and biomechanically compromised relative to normal articular cartilage. The objective of this study was to evaluate transcriptional differences between chondrocytes of normal articular cartilage and repair tissue cells four months post-microfracture.MethodsBilateral one-cm2 full-thickness defects were made in the articular surface of both distal femurs of four adult horses followed by subchondral microfracture. Four months postoperatively, repair tissue from the lesion site and grossly normal articular cartilage from within the same femorotibial joint were collected. Total RNA was isolated from the tissue samples, linearly amplified, and applied to a 9,413-probe set equine-specific cDNA microarray. Eight paired comparisons matched by limb and horse were made with a dye-swap experimental design with validation by histological analyses and quantitative real-time polymerase chain reaction (RT-qPCR).ResultsStatistical analyses revealed 3,327 (35.3%) differentially expressed probe sets. Expression of biomarkers typically associated with normal articular cartilage and fibrocartilage repair tissue corroborate earlier studies. Other changes in gene expression previously unassociated with cartilage repair were also revealed and validated by RT-qPCR.ConclusionThe magnitude of divergence in transcriptional profiles between normal chondrocytes and the cells that populate repair tissue reveal substantial functional differences between these two cell populations. At the four-month postoperative time point, the relative deficiency within repair tissue of gene transcripts which typically define articular cartilage indicate that while cells occupying the lesion might be of mesenchymal origin, they have not recapitulated differentiation to the chondrogenic phenotype of normal articular chondrocytes.

Parametric and nonparametric bootstrap methods for general MANOVA

We develop parametric and nonparametric bootstrap methods for multi-factor multivariate data, without assuming normality, and allowing for covariance matrices that are heterogeneous between groups. The newly proposed, general procedure includes several situations as special cases, such as the multivariate Behrens–Fisher problem, the multivariate one-way layout, as well as crossed and hierarchically nested two-way layouts. We derive the asymptotic distribution of the bootstrap tests for general factorial designs and evaluate their performance in an extensive comparative simulation study. For moderate sample sizes, the bootstrap approach provides an improvement to existing methods in particular for situations with nonnormal data and heterogeneous covariance matrices in unbalanced designs. For balanced designs, less computationally intensive alternatives based on approximate sampling distributions of multivariate tests can be recommended.

The effect of poison control center consultation on accidental poisoning inpatient hospitalizations with preexisting medical conditions.

In 2005, the Kentucky Poison Control Center (PCC) recorded 46,625 poisoning calls; 27% received hospital treatment. Probabilistic data linkage of accidental poisoning inpatient hospital (IPH) discharge data and PCC data (years 2000–2004) was performed. This study compared IPH with/without preexisting medical conditions and IPH with/without PCC consultation, examining total length of stay and total hospitalization charges. When compared to the IPH reference group with no preexisting medical conditions and who did not consult the PCC (mean charges =

Greenhouse–Geisser Adjustment and the ANOVA-Type Statistic: Cousins or Twins?

8748, mean length of stay = 3.2 d), PCC consultation without a preexisting medical condition was significantly associated with decreased total hospitalization charges and decreased length of stay (mean charges =

Extracorporeal Shock Wave Therapy Accelerates Regeneration After Acute Skeletal Muscle Injury.

4999, mean length of stay = 1.9 d). When the patient had a preexisting medical condition, PCC consultation was still associated with decreased total hospitalization charges and length of stay (mean charges =

Cross‐sectional study on allergic sensitization of Austrian adolescents using molecule‐based IgE profiling

8145, mean length of stay = 2.4 d) compared to those patients with a preexisting medical condition who did not consult the PCC (mean charges =

A Nonparametric Version of the Bartlett-Nanda-Pillai Multivariate Test. Asymptotics, Approximations, and Applications

10,607, mean length of stay = 3.6 d). These results suggest that after accounting for a patients age and gender, consultation with the PCC is significantly associated with reduced total hospitalization charges and reduced length of stay for IPH, and this association holds for patients with and without a preexisting medical condition.

Gene set analysis for longitudinal gene expression data

Geisser and Greenhouse described a method for repeated measures analysis of variance that has become an important part of statistical tradition. The Greenhouse–Geisser method is based on work of Box, who studied the effects of dependence on the sampling distribution of analysis of variance F ratios and derived adjustments to the degrees of freedom. In separate work on deriving small sample approximations for linear rank statistics in factorial designs, Brunner et al. proposed an F approximation with estimated degrees of freedom based on Box’s method of matching moments. In this article we show that these two descendent lines of research, although apparently divergent, actually converge for important special cases. This convergence indicates the close theoretical and practical relationships between the ANOVA-type statistic and the Greenhouse–Geisser F adjustment, which has the useful consequence that software implementations of the latter also can be used to perform many of the nonparametric tests discussed by Brunner and Puri. Furthermore, the connection indicates that further work and improvements in each area may be useful in the other areas.