@article{KarulinCaspellDittrichetal.2015,
  author    = {Karulin, Alexey Y. and Caspell, Richard and Dittrich, Marcus and Lehmann, Paul V.},
  title     = {Normal distribution of CD8+ T-cell-derived ELISPOT counts within replicates justifies the reliance on parametric statistics for identifying positive responses},
  series = {Cells},
  volume    = {4},
  journal   = {Cells},
  number    = {1},
  doi       = {10.3390/cells4010096},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149968},
  pages     = {96-111},
  year      = {2015},
  abstract  = {Accurate assessment of positive ELISPOT responses for low frequencies of antigen-specific T-cells is controversial. In particular, it is still unknown whether ELISPOT counts within replicate wells follow a theoretical distribution function, and thus whether high power parametric statistics can be used to discriminate between positive and negative wells. We studied experimental distributions of spot counts for up to 120 replicate wells of IFN-γ production by CD8+ T-cell responding to EBV LMP2A (426 - 434) peptide in human PBMC. The cells were tested in serial dilutions covering a wide range of average spot counts per condition, from just a few to hundreds of spots per well. Statistical analysis of the data using diagnostic Q-Q plots and the Shapiro-Wilk normality test showed that in the entire dynamic range of ELISPOT spot counts within replicate wells followed a normal distribution. This result implies that the Student t-Test and ANOVA are suited to identify positive responses. We also show experimentally that borderline responses can be reliably detected by involving more replicate wells, plating higher numbers of PBMC, addition of IL-7, or a combination of these. Furthermore, we have experimentally verified that the number of replicates needed for detection of weak responses can be calculated using parametric statistics.},
  language  = {en}
}
@article{KarulinKaracsonyZhangetal.2015,
  author    = {Karulin, Alexey Y. and Karacsony, Kinga and Zhang, Wenji and Targoni, Oleg S. and Moldova, Ioana and Dittrich, Marcus and Sundararaman, Srividya and Lehmann, Paul V.},
  title     = {ELISPOTs produced by CD8 and CD4 cells follow Log Normal size distribution permitting objective counting},
  series = {Cells},
  volume    = {4},
  journal   = {Cells},
  number    = {1},
  doi       = {10.3390/cells4010056},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149648},
  pages     = {56-70},
  year      = {2015},
  abstract  = {Each positive well in ELISPOT assays contains spots of variable sizes that can range from tens of micrometers up to a millimeter in diameter. Therefore, when it comes to counting these spots the decision on setting the lower and the upper spot size thresholds to discriminate between non-specific background noise, spots produced by individual T cells, and spots formed by T cell clusters is critical. If the spot sizes follow a known statistical distribution, precise predictions on minimal and maximal spot sizes, belonging to a given T cell population, can be made. We studied the size distributional properties of IFN-γ, IL-2, IL-4, IL-5 and IL-17 spots elicited in ELISPOT assays with PBMC from 172 healthy donors, upon stimulation with 32 individual viral peptides representing defined HLA Class I-restricted epitopes for CD8 cells, and with protein antigens of CMV and EBV activating CD4 cells. A total of 334 CD8 and 80 CD4 positive T cell responses were analyzed. In 99.7\% of the test cases, spot size distributions followed Log Normal function. These data formally demonstrate that it is possible to establish objective, statistically validated parameters for counting T cell ELISPOTs.},
  language  = {en}
}
@article{FlorenKruegerMuelleretal.2015,
  author    = {Floren, Andreas and Kr{\"u}ger, Dirk and M{\"u}ller, Tobias and Dittrich, Marcus and Rudloff, Renate and Hoppe, Bj{\"o}rn and Linsenmair, Karl Eduard},
  title     = {Diversity and interactions of wood-inhabiting fungi and beetles after deadwood enrichment},
  series = {PLoS ONE},
  volume    = {10},
  journal   = {PLoS ONE},
  number    = {11},
  doi       = {10.1371/journal.pone.0143566},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-145129},
  pages     = {e0143566},
  year      = {2015},
  abstract  = {Freshly cut beech deadwood was enriched in the canopy and on the ground in three cultural landscapes in Germany (Swabian Alb, Hainich-Dun, Schorfheide-Chorin) in order to analyse the diversity, distribution and interaction of wood-inhabiting fungi and beetles. After two years of wood decay 83 MOTUs (Molecular Operational Taxonomic Units) from 28 wood samples were identified. Flight Interception Traps (FITs) installed adjacent to the deadwood enrichments captured 29.465 beetles which were sorted to 566 species. Geographical 'region' was the main factor determining both beetle and fungal assemblages. The proportions of species occurring in all regions were low. Statistic models suggest that assemblages of both taxa differed between stratum and management praxis but their strength varied among regions. Fungal assemblages in Hainich-Dun, for which the data was most comprehensive, discriminated unmanaged from extensively managed and age-class forests (even-aged timber management) while canopy communities differed not from those near the ground. In contrast, the beetle assemblages at the same sites showed the opposite pattern. We pursued an approach in the search for fungus-beetle associations by computing cross correlations and visualize significant links in a network graph. These correlations can be used to formulate hypotheses on mutualistic relationships for example in respect to beetles acting as vectors of fungal spores.},
  language  = {en}
}
@article{AppelScholzMuelleretal.2015,
  author    = {Appel, Mirjam and Scholz, Claus-J{\"u}rgen and M{\"u}ller, Tobias and Dittrich, Marcus and K{\"o}nig, Christian and Bockstaller, Marie and Oguz, Tuba and Khalili, Afshin and Antwi-Adjei, Emmanuel and Schauer, Tamas and Margulies, Carla and Tanimoto, Hiromu and Yarali, Ayse},
  title     = {Genome-Wide Association Analyses Point to Candidate Genes for Electric Shock Avoidance in Drosophila melanogaster},
  series = {PLoS ONE},
  volume    = {10},
  journal   = {PLoS ONE},
  number    = {5},
  doi       = {10.1371/journal.pone.0126986},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-152006},
  pages     = {e0126986},
  year      = {2015},
  abstract  = {Electric shock is a common stimulus for nociception-research and the most widely used reinforcement in aversive associative learning experiments. Yet, nothing is known about the mechanisms it recruits at the periphery. To help fill this gap, we undertook a genome-wide association analysis using 38 inbred Drosophila melanogaster strains, which avoided shock to varying extents. We identified 514 genes whose expression levels and/or sequences covaried with shock avoidance scores. We independently scrutinized 14 of these genes using mutants, validating the effect of 7 of them on shock avoidance. This emphasizes the value of our candidate gene list as a guide for follow-up research. In addition, by integrating our association results with external protein-protein interaction data we obtained a shock avoidance- associated network of 38 genes. Both this network and the original candidate list contained a substantial number of genes that affect mechanosensory bristles, which are hairlike organs distributed across the fly's body. These results may point to a potential role for mechanosensory bristles in shock sensation. Thus, we not only provide a first list of candidate genes for shock avoidance, but also point to an interesting new hypothesis on nociceptive mechanisms.},
  language  = {en}
}
@article{KuhnGrippFliederetal.2015,
  author    = {Kuhn, Joachim and Gripp, Tatjana and Flieder, Tobias and Dittrich, Marcus and Hendig, Doris and Busse, Jessica and Knabbe, Cornelius and Birschmann, Ingvild},
  title     = {UPLC-MRM Mass Spectrometry Method for Measurement of the Coagulation Inhibitors Dabigatran and Rivaroxaban in Human Plasma and Its Comparison with Functional Assays},
  series = {PLOS ONE},
  volume    = {10},
  journal   = {PLOS ONE},
  number    = {12},
  doi       = {10.1371/journal.pone.0145478},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136023},
  pages     = {e0145478},
  year      = {2015},
  abstract  = {Introduction The fast, precise, and accurate measurement of the new generation of oral anticoagulants such as dabigatran and rivaroxaban in patients' plasma my provide important information in different clinical circumstances such as in the case of suspicion of overdose, when patients switch from existing oral anticoagulant, in patients with hepatic or renal impairment, by concomitant use of interaction drugs, or to assess anticoagulant concentration in patients' blood before major surgery. Methods Here, we describe a quick and precise method to measure the coagulation inhibitors dabigatran and rivaroxaban using ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry in multiple reactions monitoring (MRM) mode (UPLC-MRM MS). Internal standards (ISs) were added to the sample and after protein precipitation; the sample was separated on a reverse phase column. After ionization of the analytes the ions were detected using electrospray ionization-tandem mass spectrometry. Run time was 2.5 minutes per injection. Ion suppression was characterized by means of post-column infusion. Results The calibration curves of dabigatran and rivaroxaban were linear over the working range between 0.8 and 800 mu g/L (r > 0.99). Limits of detection (LOD) in the plasma matrix were 0.21 mu g/L for dabigatran and 0.34 mu g/L for rivaroxaban, and lower limits of quantification (LLOQ) in the plasma matrix were 0.46 mu g/L for dabigatran and 0.54 mu g/L for rivaroxaban. The intraassay coefficients of variation (CVs) for dabigatran and rivaroxaban were < 4\% and 6\%; respectively, the interassay CVs were < 6\% for dabigatran and < 9\% for rivaroxaban. Inaccuracy was < 5\% for both substances. The mean recovery was 104.5\% (range 83.8-113.0\%) for dabigatran and 87.0\%(range 73.6-105.4\%) for rivaroxaban. No significant ion suppressions were detected at the elution times of dabigatran or rivaroxaban. Both coagulation inhibitors were stable in citrate plasma at -20 degrees C, 4 degrees C and even at RT for at least one week. A method comparison between our UPLC-MRM MS method, the commercially available automated Direct Thrombin Inhibitor assay (DTI assay) for dabigatran measurement from CoaChrom Diagnostica, as well as the automated anti-Xa assay for rivaroxaban measurement from Chromogenix both performed by ACL-TOP showed a high degree of correlation. However, UPLC-MRM MS measurement of dabigatran and rivaroxaban has a much better selectivity than classical functional assays measuring activities of various coagulation factors which are susceptible to interference by other coagulant drugs. Conclusions Overall, we developed and validated a sensitive and specific UPLC-MRM MS assay for the quick and specific measurement of dabigatran and rivaroxaban in human plasma.},
  language  = {en}
}