Platelet size distribution in mice following immunothrombopenia and vincristine administration

In the present study platelet size distribution was investigated after induction of immunothrombocytopenia by rabbit-anti-mouse-platelet-serum (RAMPS) and after vincristine-induced thrombocytopenia. The platelet size distribution after a single dose of RAMPS showed a shift to larger volumes at day 1 and 2, and a decrease to slightly smaller volumes than normal at day 8. These differences, however, were not statistically significant. After vincristine administration, a dose-dependent increase of the platelet size distribution was demonstrated, which lasted from day 1-7. It is suggested that in immune-induced thrombocytopenia the young platelets released from bone marrow megakaryocytes are not exclusively large platelets. On the other hand the early appearance of large platelets after vincristine administration points to a toxic or segregating effect of vincristine on circulating platelets. Therefore, in our experiments, the platelet size is not suitable for the differentiation of young and old platelets.     

Hirschsprung's disease prevalence in Europe: A register based study

Background: Hirschsprung's disease is a congenital gut motility disorder, characterised by the absence of the enteric ganglion cells along the distal gut. The aim of this study was to describe the epidemiology of Hirschsprung's disease, including additional congenital anomalies, total prevalence, trends, and association with maternal age. Methods: Cases of Hirschsprung's disease delivered during 1980 to 2009 notified to 31 European Surveillance of Congenital Anomaly registers formed the population‐based case‐series. Prevalence rates and 95% confidence intervals were calculated as the number of cases per 10,000 births. Multilevel Poisson regression was performed to investigate trends in prevalence, geographical variation and the association with maternal age. Results: There were 1,322 cases of Hirschsprung's disease among 12,146,210 births. The total prevalence was 1.09 (95% confidence interval, 1.03–1.15) per 10,000 births and there was a small but significant increase in prevalence over time (relative risk = 1.01; 95% credible interval, 1.00–1.02; p = 0.004). There was evidence of geographical heterogeneity in prevalence (p < 0.001). Excluding 146 (11.0%) cases with chromosomal anomalies or genetic syndromes, there were 1,176 cases (prevalence = 0.97; 95% confidence interval, 0.91–1.03 per 10,000 births), of which 137 (11.6%) had major structural anomalies. There was no evidence of a significant increased risk of Hirschsprung's disease in cases born to women aged ≥35 years compared with those aged 25 to 29 (relative risk = 1.09; 95% credible interval, 0.91–1.31; p = 0.355). Conclusion: This large population‐based study found evidence of a small increasing trend in Hirschsprung's disease and differences in prevalence by geographic location. There was also no evidence of an association with maternal age. Birth Defects Research (Part A), 100:695–702, 2014. © 2014 Wiley Periodicals, Inc.     

A method to investigate the diffusion properties of nuclear calcium

Modeling biophysical processes in general requires knowledge about underlying biological parameters. The quality of simulation results is strongly influenced by the accuracy of these parameters, hence the identification of parameter values that the model includes is a major part of simulating biophysical processes. In many cases, secondary data can be gathered by experimental setups, which are exploitable by mathematical inverse modeling techniques. Here we describe a method for parameter identification of diffusion properties of calcium in the nuclei of rat hippocampal neurons. The method is based on a Gauss-Newton method for solving a least-squares minimization problem and was formulated in such a way that it is ideally implementable in the simulation platform uG. Making use of independently published space- and time-dependent calcium imaging data, generated from laser-assisted calcium uncaging experiments, here we could identify the diffusion properties of nuclear calcium and were able to validate a previously published model that describes nuclear calcium dynamics as a diffusion process.     

Zytophotometrische Bestimmung des DNS-Gehaltes von Zellen des lymphatischen Gewebes

Zusammenfassung In Tupfpräparaten von menschlichen Tonsillen wurden die verschiedenen Zellformen bei Pappenheim-Färbung identifiziert und photographisch festgehalten. Im anschließend angefertigten Feulgen-Präparat konnten die jeweils identifizierten Zellen wiedergefunden und in ihrem DNS-Gehalt zytophotometrisch bestimmt werden.Wir fanden, daß alle Lymphocyten, Plasmazellen und Germinocyten sowie die wenigen gemessenen Gewebsmastzellen diploid waren, während die basophilen größeren Zellen (Germmoblasten, Plasmoblasten, basophile Stammzellen) eine rege DNS-Synthese zeigten und daher als diploide, hyperdiploide und tetraploide Formen vorkamen. Sicher hypertetraploide Zellen wurden nicht gefunden. Die phagocytierenden und nicht-phagocytierenden Retikulumzellen waren meist diploid, wiesen jedoch gelegentlich auch eine DNS-Synthese auf.Die früher mitgeteilte karyometrische Klassifizierung der lymphatischen Zellen kann mit deren DNS-Gehalt nicht sinnfällig korreliert werden. Für die gesetzmäßige Differenz der Kernvolumina müssen somit andere chemische Bestandteile des Zellkernes verantwortlich sein.

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Summary The various cell types of human tonsils have been identified and photographically documented on imprints with the Pappenheim stain. The slides were then restained with the Feulgen-method. By this way we were able to reidentify these cells and to determine their DNA-content with a cytophotometric method.Lymphocytes, plasma cells and germinocytes as well as the few measured tissular mast cells are diploid. The larger basophilic cells (germinoblasts, plasmoblasts and basophilic stem cells) show an active DNA synthesis which corresponds to diploid, hyperdiploid and tetradiploid cells. Any hypertetraploid cell could not be found with certainty. Most of the reticulum cells with and without phagocytic activity are diploid, but some of them also show a DNA synthesis.The formerly published caryometric classification of the lymphoid cells cannot be accurately correlated to their DNA content. Hence, other chemical nuclear constituents must be responsible for the consistent differences between the nuclear volumina.

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Herrn Professor Dr. W. Bargmann zum 60. Geburtstag.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Neutrophil extracellular traps directly induce epithelial and endothelial cell death: a predominant role of histones

Neutrophils play an important role in innate immunity by defending the host organism against invading microorganisms. Antimicrobial activity of neutrophils is mediated by release of antimicrobial peptides, phagocytosis as well as formation of neutrophil extracellular traps (NET). These structures are composed of DNA, histones and granular proteins such as neutrophil elastase and myeloperoxidase. This study focused on the influence of NET on the host cell functions, particularly on human alveolar epithelial cells as the major cells responsible for gas exchange in the lung. Upon direct interaction with epithelial and endothelial cells, NET induced cytotoxic effects in a dose-dependent manner, and digestion of DNA in NET did not change NET-mediated cytotoxicity. Pre-incubation of NET with antibodies against histones, with polysialic acid or with myeloperoxidase inhibitor but not with elastase inhibitor reduced NET-mediated cytotoxicity, suggesting that histones and myeloperoxidase are responsible for NET-mediated cytotoxicity. Although activated protein C (APC) did decrease the histone-induced cytotoxicity in a purified system, it did not change NET-induced cytotoxicity, indicating that histone-dependent cytotoxicity of NET is protected against APC degradation. Moreover, in LPS-induced acute lung injury mouse model, NET formation was documented in the lung tissue as well as in the bronchoalveolar lavage fluid. These data reveal the important role of protein components in NET, particularly histones, which may lead to host cell cytotoxicity and may be involved in lung tissue destruction.