354 research outputs found

    Ewing sarcoma of the bone. Multidisciplinary approach and oncological results in 88 patients

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    El sarcoma de Ewing óseo es un tumor poco frecuente, agresivo, que afecta principalmente a niñosy adultos jóvenes. Existe ausencia de registros en nuestro país respecto de la prevalencia de estaenfermedad, los esquemas de tratamiento utilizados y sus resultados. El objetivo fue analizar, en un grupode pacientes con sarcoma de Ewing óseo tratados con quimioterapia y cirugía de conservación de miembro,las tasas de supervivencia global, de recurrencia local y los factores de riesgo oncológicos. Se incluyó a 88pacientes. La edad media de la serie fue de 14.5 años y el seguimiento promedio de 8.8 años. La tasa de supervivencia global fue de 79.5% a los 2 años, de 69% a 5 años y de 64% a 10 años. Los factores pronósticosnegativos asociados a menor supervivencia fueron: mala respuesta a la quimioterapia, edad ≥ de 16 años,localización central, y recurrencia local. En el análisis multivariable únicamente la respuesta a la quimioterapiatuvo significancia estadística. La tasa libre de recurrencia local a 2 y 5 años fue del 87%. La mala respuesta ala quimioterapia fue el único factor significativo para la recurrencia local. Consideramos que la cirugía de conservación de miembro asociada a quimioterapia pre y postoperatoria debe ser el tratamiento para el sarcomade Ewing óseo, alcanzando de esta manera una supervivencia global a 5 años del 69%. En nuestra serie, larespuesta a la quimioterapia ha sido el factor pronóstico más relevante para supervivencia y recurrencia local.Ewing sarcoma of the bone is a rare, highly aggressive tumor that typically affects children and young adults. In Argentina, the lack of Ewing’s sarcoma registries reflects in the absence of information regarding prevalence, treatment protocols and patient´s outcome. The purpose of this study was to analyze, in a group of patients diagnosed with Ewing sarcoma of the bone, treated with chemotherapy and limb-conserving surgery, their overall survival rate, local recurrence rate, and oncological risk factors. A retrospective research was conducted between 1990 and 2017. Eighty-eight patients with Ewing sarcoma of the bone matched the inclusion criteria. Median age was 14.5 years and median follow-up was 8.8 years. Overall survival rate was 79.5%, 69% and 64% at 2, 5 and 10 years respectively. Negative prognostic factors, associated with less survival rate after univariate analysis, were: bad response to chemotherapy (tumoral necrosis 0-89%), age > 16 years-old, central tumor localization and local recurrence. Gender and tumor size were not significant prognostic factors. After multivariate analysis, response to chemotherapy remained statistical significant. Local recurrence-free survival rate at 2 and 5 years was 87%. Tumor response to chemotherapy (0-89%) was the only significant factor for local recurrence. We consider that limb-salvage surgery, with neoadjuvant and adjuvant chemotherapy, are the mainstays of treatment for Ewing’s sarcoma, with an overall survival rate, at 5 years, of 69%. In this population, response to chemotherapy is the most relevant prognostic factor, being associated with both local recurrence and overall survival.Fil: Sanchez Saba, Javier E.. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Abrego, Mariano O.. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Albergo, José I.. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Farfalli, Germán Luis. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Aponte Tinao, Luis A.. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Ayerza, Miguel A.. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Cayol, Federico. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Streitenberger, Patricia. Instituto Universidad Escuela de Medicina del Hospital Italiano; ArgentinaFil: Risk, Marcelo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Hospital Italiano. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Instituto Universitario Hospital Italiano de Buenos Aires. Instituto de Medicina Traslacional E Ingenieria Biomedica.; ArgentinaFil: Roitman, Pablo Daniel. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentin

    Norms, Networks, Power, and Control: Understanding Informal Payments and Brokerage in Cross-Border Trade in Sierra Leone

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    Recent research has cast light on the variety of informal payments and practices that govern the day-to-day interactions between traders and customs agents at border posts in low-income countries. Building on this literature, this paper draws on survey and qualitative evidence in an effort to explore which groups are most advantaged and disadvantaged by the largely informal processes and norms governing cross-border trade. We find that understanding variation in strategies and outcomes across traders can only be effectively understood with reference to the importance of norms, networks, power, and the logic of control.Department for International DevelopmentBill and Melinda Gates Foundatio

    Life (and limb) in the fast-lane:Disposable people as infrastructure in Kampala’s boda boda industry

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    Motorcycle taxis, dubbed boda bodas, constitute a vital aspect of Kampala’s transportation infrastructure, yet the industry is perpetually precarious, threatened with wholesale eviction. Moreover, drivers’ lives and bodies are continually put at risk by the city’s traffic. Through a relational approach to ontology, this article asks how the boda boda industry comes into being and endures, what forms of vulnerability it entails, and what experiences, relations, and forms of urban life it produces. It argues that three forms disposability structure and arise from the industry – structural unemployment, embodied vulnerability, and infrastructural displacement. Infrastructural violence, it is argued, must be considered when describing and theorizing people as infrastructure. The article examines how boda boda drivers’ shared condition of insecurity and disposability generates intense forms of sociality, solidarity, mutual obligation, recognition, and urban vitality

    Force-Field Compensation in a Manual Tracking Task

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    This study addresses force/movement control in a dynamic “hybrid” task: the master sub-task is continuous manual tracking of a target moving along an eight-shaped Lissajous figure, with the tracking error as the primary performance index; the slave sub-task is compensation of a disturbing curl viscous field, compatibly with the primary performance index. The two sub-tasks are correlated because the lateral force the subject must exert on the eight-shape must be proportional to the longitudinal movement speed in order to perform a good tracking. The results confirm that visuo-manual tracking is characterized by an intermittent control mechanism, in agreement with previous work; the novel finding is that the overall control patterns are not altered by the presence of a large deviating force field, if compared with the undisturbed condition. It is also found that the control of interaction-forces is achieved by a combination of arm stiffness properties and direct force control, as suggested by the systematic lateral deviation of the trajectories from the nominal path and the comparison between perturbed trials and catch trials. The coordination of the two sub-tasks is quickly learnt after the activation of the deviating force field and is achieved by a combination of force and the stiffness components (about 80% vs. 20%), which is a function of the implicit accuracy of the tracking task

    High Cooperativity of the SV40 Major Capsid Protein VP1 in Virus Assembly

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    SV40 is a small, non enveloped DNA virus with an icosahedral capsid of 45 nm. The outer shell is composed of pentamers of the major capsid protein, VP1, linked via their flexible carboxy-terminal arms. Its morphogenesis occurs by assembly of capsomers around the viral minichromosome. However the steps leading to the formation of mature virus are poorly understood. Intermediates of the assembly reaction could not be isolated from cells infected with wt SV40. Here we have used recombinant VP1 produced in insect cells for in vitro assembly studies around supercoiled heterologous plasmid DNA carrying a reporter gene. This strategy yields infective nanoparticles, affording a simple quantitative transduction assay. We show that VP1 assembles under physiological conditions into uniform nanoparticles of the same shape, size and CsCl density as the wild type virus. The stoichiometry is one DNA molecule per capsid. VP1 deleted in the C-arm, which is unable to assemble but can bind DNA, was inactive indicating genuine assembly rather than non-specific DNA-binding. The reaction requires host enzymatic activities, consistent with the participation of chaperones, as recently shown. Our results demonstrate dramatic cooperativity of VP1, with a Hill coefficient of ∼6. These findings suggest that assembly may be a concerted reaction. We propose that concerted assembly is facilitated by simultaneous binding of multiple capsomers to a single DNA molecule, as we have recently reported, thus increasing their local concentration. Emerging principles of SV40 assembly may help understanding assembly of other complex systems. In addition, the SV40-based nanoparticles described here are potential gene therapy vectors that combine efficient gene delivery with safety and flexibility

    Влияние лечения методом дыхания с постоянным положительным давлением воздуха на артериальное давление в малом и большом круге кровообращения у больных с синдромом апноэ во сне

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    Twenty one patient with an apnea syndrome in a sleep were observed. The treatment consisted in breathing with an air stable positive pressure. The cure was efficacious in 18 cases. The treatment was terminated for 3 patients because of unbearability. The arterial pressure authentically decreased from 154±24/130±18 mm Hg to 134±17/91±6 mm Hg for 7 patients suffering from arterial hypertension and remained the same for 8 patients. 14 patients were examined for the pulmonary artery pressure dynamics. The pressure authentically decreased from 30.9±9.0 mm Hg to 23.8±7.2 mm Hg for 10 patients, increased from 21.7±2.4 mm Hg up to 29.6±2.0 mm Hg for 3 patients and remained unchanged for one patient. In the course of treating patients with hypoxemia the pC02 — 16—decreased and the p02 increased. However pulmonary ventilation indices changed negligibly. The technique of breathing under a stable positive pressure is recommended for a wide hospital cure of patients with an apnea syndrome in sleep.Авторы наблюдали 21 пациента с синдромом апноэ во сне, получавших терапию методом дыхания с постоянным положительным давлением воздуха. В 18 случаях лечение было эффективным, а у 3 пациентов было прекращено из-за его непереносимости. У больных с артериальной гипертензией в 7 случаях артериальное давление достоверно снизилось с 154±24/130±18 мм рт. ст. до 134±17/91±6 мм рт.ст., а у 8 осталось без изменений. Давление в легочной артерии исследовалось в динамике у 14 пациентов. Оно достоверно снизилось у 10 больных с 30,9±9,0 мм рт. ст. до 23,8±7,2 мм рт. ст., достоверно повысилось у 3 с 21,7±2,4 мм рт. ст. до 29,6±2,0 мм рт. ст. и не изменилось у 1 пациента. В процессе лечения отмечено снижение рС02, а также повышении рО2 у пациентов с исходной гипоксемией. При этом показатели вентиляционной функции легких изменились незначительно. Рекомендовано широкое применение метода дыхания с постоянным положительным давлением воздуха для лечения больных с синдромом апноэ во сне в условиях терапевтического стационара

    High Accordance in Prognosis Prediction of Colorectal Cancer across Independent Datasets by Multi-Gene Module Expression Profiles

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    A considerable portion of patients with colorectal cancer have a high risk of disease recurrence after surgery. These patients can be identified by analyzing the expression profiles of signature genes in tumors. But there is no consensus on which genes should be used and the performance of specific set of signature genes varies greatly with different datasets, impeding their implementation in the routine clinical application. Instead of using individual genes, here we identified functional multi-gene modules with significant expression changes between recurrent and recurrence-free tumors, used them as the signatures for predicting colorectal cancer recurrence in multiple datasets that were collected independently and profiled on different microarray platforms. The multi-gene modules we identified have a significant enrichment of known genes and biological processes relevant to cancer development, including genes from the chemokine pathway. Most strikingly, they recruited a significant enrichment of somatic mutations found in colorectal cancer. These results confirmed the functional relevance of these modules for colorectal cancer development. Further, these functional modules from different datasets overlapped significantly. Finally, we demonstrated that, leveraging above information of these modules, our module based classifier avoided arbitrary fitting the classifier function and screening the signatures using the training data, and achieved more consistency in prognosis prediction across three independent datasets, which holds even using very small training sets of tumors

    Controlled variations in stimulus similarity during learning determine visual discrimination capacity in freely moving mice

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    The mouse is receiving growing interest as a model organism for studying visual perception. However, little is known about how discrimination and learning interact to produce visual conditioned responses. Here, we adapted a two-alternative forced-choice visual discrimination task for mice and examined how training with equiprobable stimuli of varying similarity influenced conditioned response and discrimination performance as a function of learning. Our results indicate that the slope of the gradients in similarity during training determined the learning rate, the maximum performance and the threshold for successful discrimination. Moreover, the learning process obeyed an inverse relationship between discrimination performance and discriminative resolution, implying that sensitivity within a similarity range cannot be improved without sacrificing performance in another. Our study demonstrates how the interplay between discrimination and learning controls visual discrimination capacity and introduces a new training protocol with quantitative measures to study perceptual learning and visually-guided behavior in freely moving mice
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