2,371 research outputs found

    Synovial sarcoma of nerve

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    Tumors of peripheral nerve are largely neuroectodermal in nature and derived from 2 elements of nerve, Schwann or perineurial cells. In contrast, mesenchymal tumors affecting peripheral nerve are rare and are derived mainly from epineurial connective tissue. The spectrum of the latter is broad and includes lipoma, vascular neoplasms, hematopoietic tumors, and even meningioma. Of malignant peripheral nerve neoplasms, the vast majority are primary peripheral nerve sheath tumors. Malignancies of mesenchymal type are much less common. To date, only 12 cases of synovial sarcoma of nerve have been described. Whereas in the past, parallels were drawn between synovial sarcoma and malignant glandular schwannoma, an uncommon form of malignant peripheral nerve sheath tumor, molecular genetics have since clarified the distinction. Herein, we report 10 additional examples of molecularly confirmed synovial sarcoma, all arising within minor or major nerves. Affecting 7 female and 3 male patients, 4 tumors occurred in pediatric patients. Clinically and radiologically, most lesions were initially thought to be benign nerve sheath tumors. On reinterpretation of imaging, they were considered indeterminate in nature with some features suspicious for malignancy. Synovial sarcoma of nerve, albeit rare, seems to behave in a manner similar to its more common, soft tissue counterpart. Those affecting nerve have a variable prognosis. Definitive recommendations regarding surgery and adjuvant therapies await additional reports and long-term follow-up. The literature is reviewed and a meta-analysis is performed with respect to clinicopathologic features versus outcome

    Cancer mortality differences among urban and rural residents in Lithuania

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    <p>Abstract</p> <p>Background</p> <p>The aim of this study was to describe and to compare the cancer mortality rates in urban and rural residents in Lithuania.</p> <p>Methods</p> <p>Cancer mortality has been studied using the materials of the Lithuanian cancer registry. For the period 1993–2004 age-standardized urban and rural population mortality rates (World standard) were calculated for all malignant neoplasm's and for stomach, colorectal, lung, prostate, breast and cervical cancers. The annual percentage change (APC) was calculated using log-linear regression model, two-sided Mantel-Haenzel test was used to evaluate differences in cancer mortality among rural and urban populations.</p> <p>Results</p> <p>For males in rural population cancer mortality was higher than in urban (212.2 and 197.0 cases per 100000) and for females cancer mortality was higher in urban population (103.5 and 94.2 cases per 100000, p < 0.05). During the study period the age-standardized mortality rates decreased in both sexes in urban residents. The decreasing mortality trend in urban population was contributed by decline of the rates of lung and stomach cancer in male and breast, stomach and colorectal cancer in female. Mortality rates in both urban and rural population were increasing for prostate and cervical cancers.</p> <p>Conclusion</p> <p>This study shows that large rural and urban inequalities in cancer mortality exist in Lithuania. The contrast between the health of residents in urban and rural areas invites researchers for research projects to develop, implement, and enhance cancer prevention and early detection intervention strategies for rural populations.</p

    Recombinant human activated protein C resets thrombin generation in patients with severe sepsis – a case control study

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    INTRODUCTION: Recombinant human activated protein C (rhAPC) is the first drug for which a reduction of mortality in severe sepsis has been demonstrated. However, the mechanism by which this reduction in mortality is achieved is still not clearly defined. The aim of the present study was to evaluate the dynamics of the anticoagulant, anti-inflammatory and pro-fibrinolytic action of rhAPC in patients with severe sepsis, by comparing rhAPC-treated patients with case controls. METHODS: In this prospectively designed multicenter case control study, 12 patients who were participating in the ENHANCE study, an open-label study of rhAPC in severe sepsis, were treated intravenously with rhAPC at a constant rate of 24 ÎĽg/kg/h for a total of 96 h. Twelve controls with severe sepsis matching the inclusion criteria received standard therapy. The treatment was started within 48 h after the onset of organ failure. Blood samples were taken before the start of the infusion and at 4, 8, 24, 48, 96 and 168 h, for determination of parameters of coagulation and inflammation. RESULTS: Sepsis-induced thrombin generation as measured by thrombin-antithrombin complexes and prothrombin fragment F1+2, was reset by rhAPC within the first 8 h of infusion. The administration of rhAPC did not influence parameters of fibrinolysis and inflammation. There was no difference in outcome or occurrence of serious adverse events between the treatment group and the control group. CONCLUSION: Sepsis-induced thrombin generation in severely septic patients is reset by rhAPC within the first 8 h of infusion without influencing parameters of fibrinolysis and inflammation

    The effects of continuous venovenous hemofiltration on coagulation activation

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    INTRODUCTION: The mechanism of coagulation activation during continuous venovenous hemofiltration (CVVH) has not yet been elucidated. Insight into the mechanism(s) of hemostatic activation within the extracorporeal circuit could result in a more rational approach to anticoagulation. The aim of the present study was to investigate whether CVVH using cellulose triacetate filters causes activation of the contact factor pathway or of the tissue factor pathway of coagulation. In contrast to previous studies, CVVH was performed without anticoagulation. METHODS: Ten critically ill patients were studied prior to the start of CVVH and at 5, 15 and 30 minutes and 1, 2, 3 and 6 hours thereafter, for measurement of prothrombin fragment F1+2, soluble tissue factor, activated factor VII, tissue factor pathway inhibitor, kallikrein–C1-inhibitor and activated factor XII–C1-inhibitor complexes, tissue-type plasminogen activator, plasminogen activator inhibitor type I, plasmin–antiplasmin complexes, protein C and antithrombin. RESULTS: During the study period the prothrombin fragment F1+2 levels increased significantly in four patients (defined as group A) and did not change in six patients (defined as group B). Group A also showed a rapid increase in transmembrane pressure, indicating clotting within the filter. At baseline, the activated partial thromboplastin time, the prothrombin time and the kallikrein–C1-inhibitor complex and activated factor XII–C1-inhibitor complex levels were significantly higher in group B, whereas the platelet count was significantly lower in group B. For the other studied markers the differences between group A and group B at baseline were not statistically significant. During CVVH the difference in the time course between group A and group B was not statistically significant for the markers of the tissue factor system (soluble tissue factor, activated factor VII and tissue factor pathway inhibitor), for the markers of the contact system (kallikrein–C1-inhibitor and activated factor XII–C1-inhibitor complexes) and for the markers of the fibrinolytic system (plasmin–antiplasmin complexes, tissue-type plasminogen activator and plasminogen activator inhibitor type I). CONCLUSION: Early thrombin generation was detected in a minority of intensive care patients receiving CVVH without anticoagulation. Systemic concentrations of markers of the tissue factor system and of the contact system did not change during CVVH. To elucidate the mechanism of clot formation during CVVH we suggest that future studies are needed that investigate the activation of coagulation directly at the site of the filter. Early coagulation during CVVH may be related to lower baseline levels of markers of contact activation

    Site-specific occurrence of nonmelanoma skin cancers in patients with cutaneous melanoma

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    In a registry-based case–control study, we compared the site-specific occurrence of nonmelanoma (keratinocytic) skin cancers among patients with cutaneous melanoma cases (cases, n=3774) and solid tumours (controls, n=349 923), respectively. Overall, patients with melanoma were almost five-fold more likely to develop keratinocytic cancers compared with solid tumour controls (adjusted OR 4.7, 95% CI 4.1–5.3), but the risks varied depending upon the site of melanoma. Whereas patients with melanoma of the head and neck had similarly increased risks of keratinocytic cancers across all body sites, patients with melanoma of the trunk were significantly more likely to develop keratinocyte cancer diagnosed on the trunk (adjusted OR 12.5, 95% CI 7.2–20.2) than on the head and neck (adjusted OR 3.0, 95% CI 2.2–4.3). Similar colocalisation of skin tumours was observed for patients with melanomas of the lower limb. These findings provide support for the hypothesis that skin cancers at different anatomical sites may arise through different causal pathways

    String Theory on Warped AdS_3 and Virasoro Resonances

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    We investigate aspects of holographic duals to time-like warped AdS_3 space-times--which include G\"odel's universe--in string theory. Using worldsheet techniques similar to those that have been applied to AdS_3 backgrounds, we are able to identify space-time symmetry algebras that act on the dual boundary theory. In particular, we always find at least one Virasoro algebra with computable central charge. Interestingly, there exists a dense set of points in the moduli space of these models in which there is actually a second commuting Virasoro algebra, typically with different central charge than the first. We analyze the supersymmetry of the backgrounds, finding related enhancements, and comment on possible interpretations of these results. We also perform an asymptotic symmetry analysis at the level of supergravity, providing additional support for the worldsheet analysis.Comment: 24 pages + appendice

    ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument

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    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for the Mayall telescope at Kitt Peak National Observatory will deliver light to 5,000 individually targeted fiber-fed robotic positioners. The fibers in turn feed ten broadband multi-object spectrographs. We describe the ProtoDESI experiment, that was installed and commissioned on the 4-m Mayall telescope from August 14 to September 30, 2016. ProtoDESI was an on-sky technology demonstration with the goal to reduce technical risks associated with aligning optical fibers with targets using robotic fiber positioners and maintaining the stability required to operate DESI. The ProtoDESI prime focus instrument, consisting of three fiber positioners, illuminated fiducials, and a guide camera, was installed behind the existing Mosaic corrector on the Mayall telescope. A Fiber View Camera was mounted in the Cassegrain cage of the telescope and provided feedback metrology for positioning the fibers. ProtoDESI also provided a platform for early integration of hardware with the DESI Instrument Control System that controls the subsystems, provides communication with the Telescope Control System, and collects instrument telemetry data. Lacking a spectrograph, ProtoDESI monitored the output of the fibers using a Fiber Photometry Camera mounted on the prime focus instrument. ProtoDESI was successful in acquiring targets with the robotically positioned fibers and demonstrated that the DESI guiding requirements can be met.Comment: Accepted versio

    Pion and Vector Meson Form Factors in the Kuperstein-Sonnenschein holographic model

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    We study phenomenological aspects of the holographic model of chiral symmetry breaking recently introduced by Kuperstein and Sonnenschein (KS). As a first step, we calculate the spectrum of vector and axial-vector mesons in the KS model. We numerically compute various coupling constants of the mesons and pions. Our analysis indicates that vector meson dominance is realized in this model. The pion, vector meson and axial-vector meson form factors are obtained and studied in detail. We find good agreement with QCD results. In particular, the pion form factor closely matches available experimental data.Comment: v1: 27 pages, 9 figures, 4 tables; v2: minor changes, added more general discussion of vector meson dominance; v3: minor changes and additions, version accepted for publication in JHE

    Object Detection Through Exploration With A Foveated Visual Field

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    We present a foveated object detector (FOD) as a biologically-inspired alternative to the sliding window (SW) approach which is the dominant method of search in computer vision object detection. Similar to the human visual system, the FOD has higher resolution at the fovea and lower resolution at the visual periphery. Consequently, more computational resources are allocated at the fovea and relatively fewer at the periphery. The FOD processes the entire scene, uses retino-specific object detection classifiers to guide eye movements, aligns its fovea with regions of interest in the input image and integrates observations across multiple fixations. Our approach combines modern object detectors from computer vision with a recent model of peripheral pooling regions found at the V1 layer of the human visual system. We assessed various eye movement strategies on the PASCAL VOC 2007 dataset and show that the FOD performs on par with the SW detector while bringing significant computational cost savings.Comment: An extended version of this manuscript was published in PLOS Computational Biology (October 2017) at https://doi.org/10.1371/journal.pcbi.100574
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