@article{HaertleMaierhoferBoecketal.2017,
  author    = {Haertle, Larissa and Maierhofer, Anna and B{\"o}ck, Julia and Lehnen, Harald and B{\"o}ttcher, Yvonne and Bl{\"u}her, Matthias and Schorsch, Martin and Potabattula, Ramya and El Hajj, Nady and Appenzeller, Silke and Haaf, Thomas},
  title     = {Hypermethylation of the non-imprinted maternal MEG3 and paternal MEST alleles is highly variable among normal individuals},
  series = {PLoS ONE},
  volume    = {12},
  journal   = {PLoS ONE},
  number    = {8},
  doi       = {10.1371/journal.pone.0184030},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170433},
  pages     = {e0184030},
  year      = {2017},
  abstract  = {Imprinted genes show parent-specific activity (functional haploidy), which makes them particularly vulnerable to epigenetic dysregulation. Here we studied the methylation profiles of oppositely imprinted genes at single DNA molecule resolution by two independent parental allele-specific deep bisulfite sequencing (DBS) techniques. Using Roche (GSJunior) next generation sequencing technology, we analyzed the maternally imprinted MEST promoter and the paternally imprinted MEG3 intergenic (IG) differentially methylated region (DMR) in fetal cord blood, adult blood, and visceral adipose tissue. Epimutations were defined as paternal or maternal alleles with >50\% aberrantly (de)methylated CpG sites, showing the wrong methylation imprint. The epimutation rates (range 2-66\%) of the paternal MEST and the maternal MEG3 IG DMR allele, which should be completely unmethylated, were significantly higher than those (0-15\%) of the maternal MEST and paternal MEG3 alleles, which are expected to be fully methylated. This hypermethylation of the non-imprinted allele (HNA) was independent of parental origin. Very low epimutation rates in sperm suggest that HNA occurred after fertilization. DBS with Illumina (MiSeq) technology confirmed HNA for the MEST promoter and the MEG3 IG DMR, and to a lesser extent, for the paternally imprinted secondary MEG3 promoter and the maternally imprinted PEG3 promoter. HNA leads to biallelic methylation of imprinted genes in a considerable proportion of normal body cells (somatic mosaicism) and is highly variable between individuals. We propose that during development and differentiation maintenance of differential methylation at most imprinting control regions may become to some extent redundant. The accumulation of stochastic and environmentally-induced methylation errors on the non-imprinted allele may increase epigenetic diversity between cells and individuals.},
  language  = {en}
}
@article{KoesslerSchwarzWeberetal.2017,
  author    = {Koessler, Juergen and Schwarz, Michaela and Weber, Katja and Etzel, Julia and Koessler, Angela and Boeck, Markus and Kobsar, Anna},
  title     = {The role of adenosine diphosphate mediated platelet responsiveness for the stability of platelet integrity in citrated whole blood under ex vivo conditions},
  series = {PLoS ONE},
  volume    = {12},
  journal   = {PLoS ONE},
  number    = {11},
  doi       = {10.1371/journal.pone.0188193},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159879},
  pages     = {e0188193},
  year      = {2017},
  abstract  = {Background: Platelets are important for effective hemostasis and considered to be involved in pathophysiological processes, e.g. in cardiovascular diseases. Platelets provided for research or for therapeutic use are frequently separated from citrated whole blood (WB) stored for different periods of time. Although functionally intact platelets are required, the stability of platelet integrity, e.g. adenosine diphosphate (ADP) mediated responsiveness, has never been thoroughly investigated in citrated WB under ex vivo conditions. Objectives: Platelet integrity was evaluated at different time points in citrated WB units, collected from healthy donors and stored for 5 days at ambient temperature. The analysis included the measurement of activation markers, of induced light transmission aggregometry and of purinergic receptor expression or function. Inhibitory pathways were explored by determination of basal vasodilator-stimulated phosphoprotein (VASP)-phosphorylation, intracellular cyclic nucleotide levels and the content of phosphodiesterase 5A. Fresh peripheral blood (PB) samples served as controls. Results: On day 5 of storage, thrombin receptor activating peptide-6 (TRAP-6) stimulated CD62P expression and fibrinogen binding were comparable to PB samples. ADP induced aggregation continuously decreased during storage. Purinergic receptor expression remained unchanged, whereas the P2Y1 activity progressively declined in contrast to preserved P2Y12 and P2X1 function. Inhibitory pathways were unaffected except for a slight elevation of VASP phosphorylation at Ser\(^{239}\) on day 5. Conclusion: After 5 days of storage in citrated WB, platelet responsiveness to TRAP-6 is sufficiently maintained. However, ADP-mediated platelet integrity is more sensitive to deterioration, especially after storage for more than 2 days. Decreasing ADP-induced aggregation is particularly caused by the impairment of the purinergic receptor P2Y1 activity. These characteristics should be considered in the use of platelets from stored citrated WB for experimental or therapeutic issues.},
  language  = {en}
}
@article{KlughammerDittrichBlometal.2017,
  author    = {Klughammer, Johanna and Dittrich, Marcus and Blom, Jochen and Mitesser, Vera and Vogel, Ulrich and Frosch, Matthias and Goesmann, Alexander and M{\"u}ller, Tobias and Schoen, Christoph},
  title     = {Comparative genome sequencing reveals within-host genetic changes in Neisseria meningitidis during invasive disease},
  series = {PLoS ONE},
  volume    = {12},
  journal   = {PLoS ONE},
  number    = {1},
  doi       = {10.1371/journal.pone.0169892},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159547},
  pages     = {e0169892},
  year      = {2017},
  abstract  = {Some members of the physiological human microbiome occasionally cause life-threatening disease even in immunocompetent individuals. A prime example of such a commensal pathogen is Neisseria meningitidis, which normally resides in the human nasopharynx but is also a leading cause of sepsis and epidemic meningitis. Using N. meningitidis as model organism, we tested the hypothesis that virulence of commensal pathogens is a consequence of within host evolution and selection of invasive variants due to mutations at contingency genes, a mechanism called phase variation. In line with the hypothesis that phase variation evolved as an adaptation to colonize diverse hosts, computational comparisons of all 27 to date completely sequenced and annotated meningococcal genomes retrieved from public databases showed that contingency genes are indeed enriched for genes involved in host interactions. To assess within-host genetic changes in meningococci, we further used ultra-deep whole-genome sequencing of throat-blood strain pairs isolated from four patients suffering from invasive meningococcal disease. We detected up to three mutations per strain pair, affecting predominantly contingency genes involved in type IV pilus biogenesis. However, there was not a single (set) of mutation(s) that could invariably be found in all four pairs of strains. Phenotypic assays further showed that these genetic changes were generally not associated with increased serum resistance, higher fitness in human blood ex vivo or differences in the interaction with human epithelial and endothelial cells in vitro. In conclusion, we hypothesize that virulence of meningococci results from accidental emergence of invasive variants during carriage and without within host evolution of invasive phenotypes during disease progression in vivo.},
  language  = {en}
}
@article{RadakovicReboredoHelmetal.2017,
  author    = {Radakovic, D. and Reboredo, J. and Helm, M. and Weigel, T. and Sch{\"u}rlein, S. and Kupczyk, E. and Leyh, R. G. and Walles, H. and Hansmann, J.},
  title     = {A multilayered electrospun graft as vascular access for hemodialysis},
  series = {PLoS ONE},
  volume    = {12},
  journal   = {PLoS ONE},
  number    = {10},
  doi       = {10.1371/journal.pone.0185916},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159102},
  pages     = {e0185916},
  year      = {2017},
  abstract  = {Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access—an autogenous arteriovenous fistula—is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.},
  language  = {en}
}