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Jeff W Higdon Olaf RP Bininda-Emonds Robin MD Beck Steven H Ferguson 《BMC evolutionary biology》2007,7(1):216
Background
Phylogenetic comparative methods are often improved by complete phylogenies with meaningful branch lengths (e.g., divergence dates). This study presents a dated molecular supertree for all 34 world pinniped species derived from a weighted matrix representation with parsimony (MRP) supertree analysis of 50 gene trees, each determined under a maximum likelihood (ML) framework. Divergence times were determined by mapping the same sequence data (plus two additional genes) on to the supertree topology and calibrating the ML branch lengths against a range of fossil calibrations. We assessed the sensitivity of our supertree topology in two ways: 1) a second supertree with all mtDNA genes combined into a single source tree, and 2) likelihood-based supermatrix analyses. Divergence dates were also calculated using a Bayesian relaxed molecular clock with rate autocorrelation to test the sensitivity of our supertree results further. 相似文献33.
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Biomechanical stress-induced apoptosis in vein grafts involves p38 mitogen-activated protein kinases. 总被引:15,自引:0,他引:15
The present study was designed to investigate whether apoptosis occurs in early-stage vein grafts and to determine the mechanisms by which mechanical stress contributes to apoptosis in vascular smooth muscle cells (SMCs). Apoptosis in vessel walls of mouse vein grafts was confirmed by morphological changes and by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). TUNEL(+) cells in vein grafts 1, 4, and 8 wk postoperatively was 13%, 29%, and 21%, respectively, and apoptosis occurred mainly in veins grafted to arteries, remaining unchanged in vein-to-vein grafts. When mouse, rat, and human arterial SMCs were cultured on a flexible membrane and subjected to cyclic strain stress, apoptosis was observed in a time- and strength-dependent manner. All three types of SMCs showed apoptotic death as confirmed by TUNEL, propidium iodide, and annexin V staining. To further study the signal pathways leading to apoptosis, activities of p38, a subfamily of mitogen-activated protein kinases (MAPKs), were determined. Mechanical stress resulted in p38 MAPK activation, reaching high levels within 8 min. SB 202190, a specific inhibitor for p38 MAPKs, prevented SMC apoptosis in response to mechanical stress. SMC lines stably transfected with a dominant negative rac, an upstream signal transducer, or overexpressing MAPK phosphatase-1, a negative regulator for MAPKs, completely inhibited mechanical stress stimulated p38 activation and abolished mechanical stress-induced apoptosis. Thus, we provide solid evidence that one of the earliest events in venous bypass grafts is apoptosis, in which mechanical stress-induced p38-MAPK activation is responsible for transducing signals leading to apoptosis.-Mayr, M., Li, C., Zou, Y., Huemer, U., Hu, Y., Xu, Q. Biomechanical stress-induced apoptosis in vein grafts involves p38 mitogen-activated protein kinases. 相似文献
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Srikanth Mairpady Shambat Alejandro Gmez-Mejia Tiziano A. Schweizer Markus Huemer Chun-Chi Chang Claudio Acevedo Judith Bergada-Pijuan Clment Vulin Daniel A. Hofmaenner Thomas C. Scheier Sanne Hertegonne Elena Parietti Nataliya Miroshnikova Pedro D. Wendel Garcia Matthias P. Hilty Philipp Karl Buehler Reto A. Schuepbach Silvio D. Brugger Annelies S. Zinkernagel 《PLoS pathogens》2022,18(1)
COVID-19 displays diverse disease severities and symptoms including acute systemic inflammation and hypercytokinemia, with subsequent dysregulation of immune cells. Bacterial superinfections in COVID-19 can further complicate the disease course and are associated with increased mortality. However, there is limited understanding of how SARS-CoV-2 pathogenesis and hypercytokinemia impede the innate immune function against bacterial superinfections. We assessed the influence of COVID-19 plasma hypercytokinemia on the functional responses of myeloid immune cells upon bacterial challenges from acute-phase COVID-19 patients and their corresponding recovery-phase. We show that a severe hypercytokinemia status in COVID-19 patients correlates with the development of bacterial superinfections. Neutrophils and monocytes derived from COVID-19 patients in their acute-phase showed an impaired intracellular microbicidal capacity upon bacterial challenges. The impaired microbicidal capacity was reflected by abrogated MPO and reduced NETs production in neutrophils along with reduced ROS production in both neutrophils and monocytes. Moreover, we observed a distinct pattern of cell surface receptor expression on both neutrophils and monocytes, in line with suppressed autocrine and paracrine cytokine signaling. This phenotype was characterized by a high expression of CD66b, CXCR4 and low expression of CXCR1, CXCR2 and CD15 in neutrophils and low expression of HLA-DR, CD86 and high expression of CD163 and CD11b in monocytes. Furthermore, the impaired antibacterial effector function was mediated by synergistic effect of the cytokines TNF-α, IFN-γ and IL-4. COVID-19 patients receiving dexamethasone showed a significant reduction of overall inflammatory markers in the plasma as well as exhibited an enhanced immune response towards bacterial challenge ex vivo. Finally, broad anti-inflammatory treatment was associated with a reduction in CRP, IL-6 levels as well as length of ICU stay and ventilation-days in critically ill COVID-19 patients. Our data provides insights into the transient functional dysregulation of myeloid immune cells against subsequent bacterial infections in COVID-19 patients and describe a beneficial role for the use of dexamethasone in these patients. 相似文献
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Licia Bordi Eleonora Lalle Claudia Caglioti Damiano Travaglini Daniele Lapa Patrizia Marsella Serena Quartu Zoltan Kis Kevin K. Arien Hartwig P. Huemer Silvia Meschi Giuseppe Ippolito Antonino Di Caro Maria R. Capobianchi Concetta Castilletti 《PloS one》2015,10(2)
MethodsHuman A549 and HuH7 cells were treated with increasing amounts of IFN-λ1, or IFN-α or a combination of them, infected with CCHF; the extent of virus yield inhibition and the induction of MxA and 2’-5’OAS mRNA was measured.
Results and Conclusions
Our study pointed out that type III IFN possess an antiviral activity against CCHFV, even if lower than type I IFN. Moreover, a clear antagonism between IFN-λ and IFN–α was observed in both cell lines (A549 and HuH7 cells), in terms of antiviral effect and activation of pivotal ISGs, i.e. MxA and 2’-5’OAS. Elucidating the interplay between type I and III IFNs will help to better understand innate defence mechanisms against viral infections and may provide novel scientific evidence for a more rational planning of available and future treatments, particularly against human diseases caused by high concern viruses. 相似文献39.
Schöffl H Froschauer SM Dunst KM Hager D Kwasny O Huemer GM 《Alternatives to laboratory animals : ATLA》2008,36(2):153-160
Education and training in microsurgical techniques have historically relied on the use of live animal models. Due to an increase in the numbers of microsurgical operations in recent times, the number of trainees in this highly-specialised surgical field has continued to grow. However, strict legislation, greater public awareness, and an increasing sensitivity toward the ethical aspects of scientific research and medical education, emphatically demand a significant reduction in the numbers of animals used in surgical and academic education. Hence, a growing number of articles are reporting on the use of alternatives to live animals in microsurgical education and training. In this review, we report on the current trends in the development and use of microsurgical training models, and on their potential to reduce the number of live animals used for this purpose. We also share our experiences in this field, resulting from our performance of numerous microsurgical courses each year, over more than ten years. The porcine heart, in microvascular surgery training, and the fresh chicken leg, in microneurosurgical and microvascular surgery training, are excellent models for the teaching of basic techniques to the microsurgical novice. Depending on the selected level of expertise of the trainee, these alternative models are capable of reducing the numbers of live animals used by 80-100%. For an even more enhanced, "closer-to-real-life" scenario, these non-animated vessels can be perfused by a pulsatile pump. Thus, it is currently possible to provide excellent and in-depth training in microsurgical techniques, even when the number of live animals used is reduced to a minimum. With these new and innovative techniques, trainees are able to learn and prepare themselves for the clinical situation, with the sacrifice of considerably fewer laboratory animals than would have occurred previously. 相似文献
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