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The structure of the title compound, C8H16N4, which consists of four fused seven-membered rings, has been redetermined at 173 K. This redetermination corrects the orientation of two H atoms, which were located at unrealistic positions in the original room-temperature study [Murray-Rust (1974[Murray-Rust, P. (1974). J. Chem. Soc. Perkin Trans. 2, pp. 1136-1141.]). J. Chem. Soc. Perkin Trans. 2, pp. 1136–1141]. The complete molecule is generated by -42m symmetry, with one quarter of a molecule [one N atom (site symmetry m), two C atoms (one with site symmetry m and the other with site symmetry 2) and two H atoms] in the asymmetric unit. No directional interactions beyond van der Waals contacts are apparent in the crystal structure.
The mitochondrial kinase PINK1 and the ubiquitin ligase Parkin are participating in quality control after CCCP- or ROSinduced mitochondrial damage, and their dysfunction is associated with the development and progression of Parkinson’s disease. Furthermore, PINK1 expression is also induced by starvation indicating an additional role for PINK1 in stress response. Therefore, the effects of PINK1 deficiency on the autophago-lysosomal pathway during stress were investigated. Under trophic deprivation SH-SY5Y cells with stable PINK1 knockdown showed downregulation of key autophagic genes, including Beclin, LC3 and LAMP-2. In good agreement, protein levels of LC3-II and LAMP-2 but not of LAMP-1 were reduced in different cell model systems with PINK1 knockdown or knockout after addition of different stressors. This downregulation of autophagic factors caused increased apoptosis, which could be rescued by overexpression of LC3 or PINK1. Taken together, the PINK1-mediated reduction of autophagic key factors during stress resulted in increased cell death, thus defining an additional pathway that could contribute to the progression of Parkinson’s disease in patients with PINK1 mutations.
Treatment with inhibitors of the receptor tyrosine kinase FLT3 are currently studied as promising therapies in acute myeloid leukemia (AML). However, only a subset of patients benefit from these treatments and the presence of activating mutations within FLT3 can predict response to a certain extent only. ...
CD4+CD25+ regulatory T cells (Tregs) represent a specialized subpopulation of T cells, which are essential for maintaining peripheral tolerance and preventing autoimmunity. The immunomodulatory effects of Tregs depend on their activation status. Here we show that, in contrast to conventional anti-CD4 monoclonal antibodies (mAbs), the humanized CD4-specific monoclonal antibody tregalizumab (BT-061) is able to selectively activate the suppressive properties of Tregs in vitro. BT-061 activates Tregs by binding to CD4 and activation of signaling downstream pathways. The specific functionality of BT-061 may be explained by the recognition of a unique, conformational epitope on domain 2 of the CD4 molecule that is not recognized by other anti-CD4 mAbs. We found that, due to this special epitope binding, BT-061 induces a unique phosphorylation of T-cell receptor complex-associated signaling molecules. This is sufficient to activate the function of Tregs without activating effector T cells. Furthermore, BT-061 does not induce the release of pro-inflammatory cytokines. These results demonstrate that BT-061 stimulation via the CD4 receptor is able to induce T-cell receptor-independent activation of Tregs. Selective activation of Tregs via CD4 is a promising approach for the treatment of autoimmune diseases where insufficient Treg activity has been described. Clinical investigation of this new approach is currently ongoing.
Heterogenous subtypes of breast cancer need to be analyzed separately. Pooling of datasets can provide reasonable sample sizes but dataset bias is an important concern. We assembled a combined dataset of 579 Affymetrix microarrays from triple negative breast cancer (TNBC) in Gene Expression Omnibus (GEO) series GSE31519. We developed a method for selecting comparable datasets and to control for the amount of dataset bias of individual probesets.
Am Ende seiner 'Archäologie der Humanwissenschaften' hat Michel Foucault darauf gewettet, dass der Mensch - diese "junge Erfindung" - "verschwindet wie am Meeresufer ein Gesicht im Sand." Gemeint war damit nicht die Möglichkeit der physischen Auslöschung der Gattung, die zur Zeit der Erstveröffentlichung des Buches im Jahre 1966 - unter den Bedingungen des Kalten Krieges - immerhin breit diskutiert wurde. Vielmehr erwartete Foucault eine grundlegende Transformation der Episteme, in deren Gefolge 'der Mensch' seine zentrale Stellung zur Erklärung der Gesellschaft und der Geschichte wieder verlieren würde - eine Depotenzierung und Dezentrierung des Menschen, die Foucault in den Arbeiten von Marx, Nietzsche und Freud angebahnt sah. Die aktuelle Konjunktur des Begriffs 'Anthropozän' verdient vor diesem Hintergrund besondere Beachtung.
Die Begriffsgeschichte befindet sich seit einigen Jahren in der Phase einer grundlegenden Transformation, die sich vor allem in ihrer zunehmenden Internationalisierung und Interdisziplinarisierung sowie in ihrer Verbindung mit der Kultur- und Wissenschaftsgeschichte dokumentiert. Eine besondere Herausforderung bildet dabei die Erschließung der naturwissenschaftlichen Semantik. Referenzpunkte für die gegenwärtige inhaltliche und methodische Neuausrichtung bilden unter anderem die Ansätze zu einer Historischen Epistemologie (Gaston Bachelard, Ludwik Fleck) sowie Georges Canguilhems methodische Fundierung der Wissenschaftsgeschichte in der Begriffsgeschichte. In diesem Aufsatz möchte ich einige Aspekte einer interdisziplinären Begriffs- und Wissenschaftsgeschichte anhand der Analyse der Entstehungsphase des Konzepts vom 'Survival of the fittest' diskutieren. Dieses Konzept hat sich im Zeitraum der 1860er bis 1870er Jahre zu einem Deutungsmuster entwickelt, das mit eminent politischen Folgen im Spannungsfeld biologischer, philosophischer, soziologischer, ethnologischer und ökonomischer Theoriebildung sowie zwischen verschiedenen nationalen Wissenschaftskulturen zirkulierte. Ich möchte betonen, dass die von mir fokussierte wissenshistorische Konstellation nur einen kleinen Ausschnitt aus der komplexen und weit verzweigten Geschichte des Überlebensbegriffs bildet. Insbesondere seit den 1970er Jahren im Zusammenhang der ökologischen Krise und als Effekt der Diskursmacht der von Foucault entwickelten Konzepte der Biopolitik bzw. Biomacht lässt sich eine neue Konjunktur des Überlebensbegriffs ausmachen, die bis in unsere Gegenwart reicht und die überhaupt die Voraussetzung für das Bedürfnis bildet, die Bedeutungs- und Gebrauchsgeschichte des Überlebensbegriffs, oder einzelne Etappen und Knotenpunkte derselben, zu rekonstruieren.
Background: Unlike metastatic colorectal cancer (CRC) there are to date few reports concerning the predictive value of molecular biomarkers on the clinical outcome in stage II/III CRC patients receiving adjuvant chemotherapy. Aim of this study was to assess the predictive value of proteins related with the EGFR- and VEGFR- signalling cascades in these patients.
Methods: The patients' data examined in this study were from the collective of the 5-FU/FA versus 5-FU/FA/irinotecan phase III FOGT-4 trial. Tumor tissues were stained by immunohistochemistry for VEGF-C, VEGF-D, VEGFR-3, Hif-1 α, PTEN, AREG and EREG expression and evaluated by two independent, blinded investigators. Survival analyses were calculated for all patients receiving adjuvant chemotherapy in relation to expression of all makers above.
Results: Patients with negative AREG and EREG expression on their tumor had a significant longer DFS in comparison to AREG/EREG positive ones (p< 0.05). The benefit on DFS in AREG-/EREG- patients was even stronger in the group that received 5-FU/FA/irinotecan as adjuvant treatment (p=0.002). Patients with strong expression of PTEN profited more in terms of OS under adjuvant treatment containing irinotecan (p< 0.05). Regarding markers of the VEGFR- pathway we found no correlation of VEGF-C- and VEGFR-3 expression with clinical outcome. Patients with negative VEGF-D expression had a trend to live longer when treated with 5-FU/FA (p=0.106). Patients who were negative for Hif-1 α, were disease-free in more than 50% at the end of the study and showed significant longer DFS-rates than those positive for Hif-1 α (p=0.007). This benefit was even stronger at the group treated with 5-FU/FA/irinotecan (p=0.026). Finally, AREG-/EREG-/PTEN+ patients showed a trend to live longer under combined treatment combination.
Conclusions: The addition of irinotecan to adjuvant treatment with 5-FU/FA does not provide OS or DFS benefit in patients with stage II/III CRC. Nevertheless, AREG/EREG negative, PTEN positive and Hif-1 α negative patients might profit significantly in terms of DFS from a treatment containing fluoropyrimidines and irinotecan. Our results suggest a predictive value of these biomarkers concerning adjuvant chemotherapy with 5-FU/FA +/− irinotecan in stage II/III colorectal cancer.
Selection of higher order regression models in the analysis of multi-factorial transcription data
(2014)
Introduction: Many studies examine gene expression data that has been obtained under the influence of multiple factors, such as genetic background, environmental conditions, or exposure to diseases. The interplay of multiple factors may lead to effect modification and confounding. Higher order linear regression models can account for these effects. We present a new methodology for linear model selection and apply it to microarray data of bone marrow-derived macrophages. This experiment investigates the influence of three variable factors: the genetic background of the mice from which the macrophages were obtained, Yersinia enterocolitica infection (two strains, and a mock control), and treatment/non-treatment with interferon-γ.
Results: We set up four different linear regression models in a hierarchical order. We introduce the eruption plot as a new practical tool for model selection complementary to global testing. It visually compares the size and significance of effect estimates between two nested models. Using this methodology we were able to select the most appropriate model by keeping only relevant factors showing additional explanatory power. Application to experimental data allowed us to qualify the interaction of factors as either neutral (no interaction), alleviating (co-occurring effects are weaker than expected from the single effects), or aggravating (stronger than expected). We find a biologically meaningful gene cluster of putative C2TA target genes that appear to be co-regulated with MHC class II genes.
Conclusions: We introduced the eruption plot as a tool for visual model comparison to identify relevant higher order interactions in the analysis of expression data obtained under the influence of multiple factors. We conclude that model selection in higher order linear regression models should generally be performed for the analysis of multi-factorial microarray data.
• Endomicroscopy is a new imaging tool for gastrointestinal endoscopy.
• Panchromoendoscopy with targeted biopsies has become the method of choice for surveillance of patients with inflammatory bowel disease.
• Endomicroscopy can be added after chromoendoscopy to clarify whether standard biopsies are still needed.
• This smart biopsy concept can increase the diagnostic yield of intraepithelial neoplasia and substantially reduce the need for biopsies.
• Endomicroscopy is still mainly used for research but clinical acceptance is increasing because of a multitude of positive studies about the diagnostic value of endomicroscopy.