527 research outputs found

    Tensor perturbations of f(R)f(R)-branes

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    We analyze the tensor perturbations of flat thick domain wall branes in f(R)f(R) gravity. Our results indicate that under the transverse and traceless gauge, the metric perturbations decouple from the perturbation of the scalar field. Besides, the perturbed equation reduces to the familiar Klein-Gordon equation for massless spin-2 particles only when the bulk curvature is a constant or when f(R)=Rf(R)=R. As an application of our results, we consider the possibility of localizing gravity on some flat thick branes. The stability of these brane solutions is also shortly discussed.Comment: 9 pages, 3 figures, improved version, accepted by PL

    Tumor-educated Tregs drive organ-specific metastasis in breast cancer by impairing NK cells in the lymph node niche

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    Breast cancer is accompanied by systemic immunosuppression, which facilitates metastasis formation, but how this shapes organotropism of metastasis is poorly understood. Here, we investigate the impact of mammary tumorigenesis on regulatory T cells (Tregs) in distant organs and how this affects multi-organ metastatic disease. Using a preclinical mouse mammary tumor model that recapitulates human metastatic breast cancer, we observe systemic accumulation of activated, highly immunosuppressive Tregs during primary tumor growth. Tumor-educated Tregs show tissue-specific transcriptional rewiring in response to mammary tumorigenesis. This has functional consequences for organotropism of metastasis, as Treg depletion reduces metastasis to tumor-draining lymph nodes, but not to lungs. Mechanistically, we find that Tregs control natural killer (NK) cell activation in lymph nodes, thereby facilitating lymph node metastasis. In line, an increased Treg/NK cell ratio is observed in sentinel lymph nodes of breast cancer patients compared with healthy controls. This study highlights that immune regulation of metastatic disease is highly organ dependent

    Combined and single effects of pesticide carbaryl and toxic Microcystis aeruginosa on the life history of Daphnia pulicaria

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    The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different, sub-lethal concentrations (chronic exposure). In order to determine the actual carbaryl concentrations in the water LC–MS/MS was used. For analyses of the cyanotoxin concentration in Daphnia’s body enzyme-linked immunosorbent assay (ELISA) was used. Individual daphnids were cultured in a flow-through system under constant light (16 h of light: 8 h of dark), temperature (20°C), and food conditions (Scenedesmus obliquus, 1 mg of C l−1). The results showed that in the treatments with carbaryl egg numbers per female did not differ significantly from controls, but the mortality of newborns increased significantly. Increasing microcystin concentrations significantly delayed maturation, reduced size at first reproduction, number of eggs, and newborns. The interaction between carbaryl and Microcystis was highly significant. Animals matured later and at a smaller size than in controls. The number of eggs per female was reduced as well. Moreover, combined stressors caused frequent premature delivery of offspring with body deformations such as dented carapax or an undeveloped heart. This effect is concluded to be synergistic and could not be predicted from the effects of the single stressors.

    Factor Xa Generation by Computational Modeling: An Additional Discriminator to Thrombin Generation Evaluation

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    Factor (f)Xa is a critical enzyme in blood coagulation that is responsible for the initiation and propagation of thrombin generation. Previously we have shown that analysis of computationally generated thrombin profiles is a tool to investigate hemostasis in various populations. In this study, we evaluate the potential of computationally derived time courses of fXa generation as another approach for investigating thrombotic risk. Utilizing the case (n = 473) and control (n = 426) population from the Leiden Thrombophilia Study and each individual's plasma protein factor composition for fII, fV, fVII, fVIII, fIX, fX, antithrombin and tissue factor pathway inhibitor, tissue factor-initiated total active fXa generation was assessed using a mathematical model. FXa generation was evaluated by the area under the curve (AUC), the maximum rate (MaxR) and level (MaxL) and the time to reach these, TMaxR and TMaxL, respectively. FXa generation was analyzed in the entire populations and in defined subgroups (by sex, age, body mass index, oral contraceptive use). The maximum rates and levels of fXa generation occur over a 10- to 12- fold range in both cases and controls. This variation is larger than that observed with thrombin (3–6 fold) in the same population. The greatest risk association was obtained using either MaxR or MaxL of fXa generation; with an ∼2.2 fold increased risk for individuals exceeding the 90th percentile. This risk was similar to that of thrombin generation(MaxR OR 2.6). Grouping defined by oral contraceptive (OC) use in the control population showed the biggest differences in fXa generation; a >60% increase in the MaxR upon OC use. FXa generation can distinguish between a subset of individuals characterized by overlapping thrombin generation profiles. Analysis of fXa generation is a phenotypic characteristic which may prove to be a more sensitive discriminator than thrombin generation among all individuals

    Prognostic impact of peritumoral lymphocyte infiltration in soft tissue sarcomas

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to clarify the prognostic significance of peritumoral lymphocyte infiltration in the capsule of soft tissue sarcomas (STS). Multiple observations in preclinical and clinical studies have shown that the immune system has a role in controlling tumor growth and progression. Prognostic markers in potentially curable STS should guide therapy after surgical resection. The immune status at the time of resection may be important, but the prognostic significance of peritumoral lymphocytes is unknown.</p> <p>Methods</p> <p>Tissue microarrays from 80 patients with STS were constructed from duplicate cores of tissue from the tumor and the peritumoral capsule. Immunohistochemistry was used to evaluate the CD3+, CD4+, CD8+ and CD20+ lymphocytes in the tumor and the peritumoral capsule.</p> <p>Results</p> <p>In univariate analyses, increasing numbers of CD20+ (<it>P </it>= 0.032) peritumoral lymphocytes were associated with a reduced disease free survival (DSS). In multivariate analyses, a high number of CD20+ peritumoral lymphocytes (<it>P </it>= 0.030) in the capsule was an independent negative prognostic factor for DSS. There were no such associations of lymphocyte infiltration in the tumor.</p> <p>Conclusions</p> <p>A high density of CD20+ peritumoral lymphocytes is an independent negative prognostic indicator for patients with STS. Further research is needed to determine whether CD20 cells in the peritumoral capsule of STS may promote tumor invasion in the surrounding tissue and increase the metastatic potential.</p

    Immunotherapy with MVA-BN®-HER2 induces HER-2-specific Th1 immunity and alters the intratumoral balance of effector and regulatory T cells

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    MVA-BN®-HER2 is a new candidate immunotherapy designed for the treatment of HER-2-positive breast cancer. Here, we demonstrate that a single treatment with MVA-BN®-HER2 exerts potent anti-tumor efficacy in a murine model of experimental pulmonary metastasis. This anti-tumor efficacy occurred despite a strong tumor-mediated immunosuppressive environment characterized by a high frequency of regulatory T cells (Treg) in the lungs of tumor-bearing mice. Immunogenicity studies showed that treatment with MVA-BN®-HER2 induced strongly Th1-dominated HER-2-specific antibody and T-cell responses. MVA-BN®-HER2-induced anti-tumor activity was characterized by an increased infiltration of lungs with highly activated, HER-2-specific, CD8+CD11c+ T cells accompanied by a decrease in the frequency of Treg cells in the lung, resulting in a significantly increased ratio of effector T cells to Treg cells. In contrast, administration of HER2 protein formulated in Complete Freund’s Adjuvant (CFA) induced a strongly Th2-biased immune response to HER-2. However, this did not lead to significant infiltration of the tumor-bearing lungs by CD8+ T cells or the decrease in the frequency of Treg cells nor did it result in anti-tumor efficacy. In vivo depletion of CD8+ cells confirmed that CD8 T cells were required for the anti-tumor activity of MVA-BN®-HER2. Furthermore, depletion of CD4+ or CD25+ cells demonstrated that tumor-induced Treg cells promoted tumor growth and that CD4 effector cells also contribute to MVA-BN®-HER2-mediated anti-tumor efficacy. Taken together, our data demonstrate that treatment with MVA-BN®-HER2 controls tumor growth through mechanisms including the induction of Th1-biased HER-2-specific immune responses and the control of tumor-mediated immunosuppression
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