79 research outputs found

    Diagnosis, treatment and long-term outcome of solitary fibrous tumours of the pleura

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    Objective: Solitary fibrous tumours of the pleura (SFTP) are rare and can histologically be differentiated into benign and malignant forms. The aim of this study is to present new cases, and discuss up-to-date preoperative examinations, the role of video-assisted thoracic surgery and long-term outcome. Methods: Between 1993 and 2006, 27 SFTPs were diagnosed (14 females, mean age±SD, 62.3±9.6 years) at our institution. Medical records were reviewed, and follow-up was obtained by repeated examinations or contact with general practitioners. Results: SFTPs were associated with symptoms in 63% of all cases. In the six patients in which positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) was performed preoperatively, malignant lesions were all found to be positive. Complete resection was achieved by video-assisted thoracic surgery in 15 and anterolateral thoracotomy in 12 patients. Mean hospital stay was shorter for patients operated by video-assisted thoracic surgery compared to thoracotomy, 4.5 (range 3-6) versus 7.5 (range 4-25) days, respectively (p≪0.01). Histology revealed 17 benign and 10 malignant SFTP. Mean±SD tumour diameter of malignant SFTPs was larger than in benign forms, 11.9±7.1 versus 6.1±3.5cm, respectively (p≪0.01). Tumour recurrence was recognised in four patients with malignant SFTPs at a median time interval after surgery of 38 (range 6-122) months, two late deaths occurred resulting from tumour recurrences. Conclusions: SFTPs can be treated minimally invasively by video-assisted thoracic surgery with short hospital stay. Large SFTPs with increased FDG-uptake have a high likelihood for malignancy. Long-term follow-up is mandatory in malignant SFTPs because of late recurrences associated with deat

    Noise Induced Coherence in Neural Networks

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    We investigate numerically the dynamics of large networks of NN globally pulse-coupled integrate and fire neurons in a noise-induced synchronized state. The powerspectrum of an individual element within the network is shown to exhibit in the thermodynamic limit (NN\to \infty) a broadband peak and an additional delta-function peak that is absent from the powerspectrum of an isolated element. The powerspectrum of the mean output signal only exhibits the delta-function peak. These results are explained analytically in an exactly soluble oscillator model with global phase coupling.Comment: 4 pages ReVTeX and 3 postscript figure

    Collective dynamics of two-mode stochastic oscillators

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    We study a system of two-mode stochastic oscillators coupled through their collective output. As a function of a relevant parameter four qualitatively distinct regimes of collective behavior are observed. In an extended region of the parameter space the periodicity of the collective output is enhanced by the considered coupling. This system can be used as a new model to describe synchronization-like phenomena in systems of units with two or more oscillation modes. The model can also explain how periodic dynamics can be generated by coupling largely stochastic units. Similar systems could be responsible for the emergence of rhythmic behavior in complex biological or sociological systems.Comment: 4 pages, RevTex, 5 figure

    Coherence Resonance and Noise-Induced Synchronization in Globally Coupled Hodgkin-Huxley Neurons

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    The coherence resonance (CR) of globally coupled Hodgkin-Huxley neurons is studied. When the neurons are set in the subthreshold regime near the firing threshold, the additive noise induces limit cycles. The coherence of the system is optimized by the noise. A bell-shaped curve is found for the peak height of power spectra of the spike train, being significantly different from a monotonic behavior for the single neuron. The coupling of the network can enhance CR in two different ways. In particular, when the coupling is strong enough, the synchronization of the system is induced and optimized by the noise. This synchronization leads to a high and wide plateau in the local measure of coherence curve. The local-noise-induced limit cycle can evolve to a refined spatiotemporal order through the dynamical optimization among the autonomous oscillation of an individual neuron, the coupling of the network, and the local noise.Comment: five pages, five figure

    Endothelial overexpression of LOX-1 increases plaque formation and promotes atherosclerosis in vivo

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    Aims Lectin-like oxLDL receptor-1 (LOX-1) mediates the uptake of oxidized low-density lipoprotein (oxLDL) in endothelial cells and macrophages. However, the different atherogenic potential of LOX-1-mediated endothelial and macrophage oxLDL uptake remains unclear. The present study was designed to investigate the in vivo role of endothelial LOX-1 in atherogenesis. Methods and results Endothelial-specific LOX-1 transgenic mice were generated using the Tie2 promoter (LOX-1TG). Oxidized low-density lipoprotein uptake was enhanced in cultured endothelial cells, but not in macrophages of LOX-1TG mice. Six-week-old male LOX-1TG and wild-type (WT) mice were fed a high-cholesterol diet (HCD) for 30 weeks. Increased reactive oxygen species production, impaired endothelial nitric oxide synthase activity and endothelial dysfunction were observed in LOX-1TG mice as compared with WT littermates. LOX-1 overexpression led to p38 phosphorylation, increased nuclear factor κB activity and subsequent up-regulation of vascular cell adhesion molecule-1, thereby favouring macrophage accumulation and aortic fatty streaks. Consistently, HCD-fed double-mutant LOX-1TG/ApoE−/− displayed oxidative stress and vascular inflammation with higher aortic plaques than ApoE−/− controls. Finally, bone marrow transplantation experiments showed that endothelial LOX-1 was sufficient for atherosclerosis development in vivo. Conclusions Endothelial-specific LOX-1 overexpression enhanced aortic oxLDL levels, thereby favouring endothelial dysfunction, vascular inflammation and plaque formation. Thus, LOX-1 may serve as a novel therapeutic target for atherosclerosi

    CD28/CD154 Blockade Prevents Autoimmune Diabetes by Inducing Nondeletional Tolerance After Effector T-Cell Inhibition and Regulatory T-Cell Expansion

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    OBJECTIVE—Blocking T-cell signaling is an effective means to prevent autoimmunity and allograft rejection in many animal models, yet the clinical translation of many of these approaches has not resulted in the success witnessed in experimental systems. Improved understanding of these approaches may assist in developing safe and effective means to treat disorders such as autoimmune diabetes

    Phase synchronization and noise-induced resonance in systems of coupled oscillators

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    We study synchronization and noise-induced resonance phenomena in systems of globally coupled oscillators, each possessing finite inertia. The behavior of the order parameter, which measures collective synchronization of the system, is investigated as the noise level and the coupling strength are varied, and hysteretic behavior is manifested. The power spectrum of the phase velocity is also examined and the quality factor as well as the response function is obtained to reveal noise-induced resonance behavior.Comment: to be published in Phys. Rev.

    HVEM Signalling Promotes Colitis

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    Background Tumor necrosis factor super family (TNFSF) members regulate important processes involved in cell proliferation, survival and differentiation and are therefore crucial for the balance between homeostasis and inflammatory responses. Several members of the TNFSF are closely associated with inflammatory bowel disease (IBD). Thus, they represent interesting new targets for therapeutic treatment of IBD. Methodology/Principal Findings We have used mice deficient in TNFSF member HVEM in experimental models of IBD to investigate its role in the disease process. Two models of IBD were employed: i) chemical-induced colitis primarily mediated by innate immune cells; and ii) colitis initiated by CD4+CD45RBhigh T cells following their transfer into immuno-deficient RAG1-/- hosts. In both models of disease the absence of HVEM resulted in a significant reduction in colitis and inflammatory cytokine production. Conclusions These data show that HVEM stimulatory signals promote experimental colitis driven by innate or adaptive immune cells

    Therapy of experimental type 1 diabetes by isolated Sertoli cell xenografts alone

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    Type I diabetes mellitus is caused by autoimmune destruction of pancreatic β cells, and effective treatment of the disease might require rescuing β cell function in a context of reinstalled immune tolerance. Sertoli cells (SCs) are found in the testes, where their main task is to provide local immunological protection and nourishment to developing germ cells. SCs engraft, self-protect, and coprotect allogeneic and xenogeneic grafts from immune destruction in different experimental settings. SCs have also been successfully implanted into the central nervous system to create a regulatory environment to the surrounding tissue which is trophic and counter-inflammatory. We report that isolated neonatal porcine SC, administered alone in highly biocompatible microcapsules, led to diabetes prevention and reversion in the respective 88 and 81% of overtly diabetic (nonobese diabetic [NOD]) mice, with no need for additional β cell or insulin therapy. The effect was associated with restoration of systemic immune tolerance and detection of functional pancreatic islets that consisted of glucose-responsive and insulin-secreting cells. Curative effects by SC were strictly dependent on efficient tryptophan metabolism in the xenografts, leading to TGF-β–dependent emergence of autoantigen-specific regulatory T cells and recovery of β cell function in the diabetic recipients
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