Introducción: El cáncer periampular representa el 5% de todos los cánceres del tracto gastrointestinal, siendo el cáncer de páncreas más frecuente, siendo su sobrevida de 6% a los 5 años. En Perú la incidencia de cáncer de páncreas es de 1 262 por 100 000 habitantes. Ésta incidencia es menor en países andinos, por lo cual su comportamiento podría ser distinto. La Duodenopancreatectomía Cefálica se considera una cirugía curativa si el cáncer se considera irresecable. Existen pocos estudios que evidencian los resultados de esta cirugía y factores pronósticos de sobrevida en Latinoamérica. Objetivo: Determinar las características clínico quirúrgicas de pacientes con cáncer periampular sometidos a Duodenopancreatectomía Cefálica en el Instituto Nacional de Enfermedades Neoplásicas durante el periodo Enero 2002 a Diciembre 2011 Metodología: Estudio observacional, descriptivo, retrospectivo. Resultados: Entre Enero 2002 y Diciembre 2011 se realizaron 187 DPC en el INEN, 178 ingresan al estudio. Se obtuvo una mayor prevalencia de Cáncer de ampolla de Váter resecado (56,2%), seguido del Cáncer de Páncreas (25,8%). Un 74,2% tuvieron un grado moderadamente diferenciado. El estado de supervivencia global a los 3 años posteriores a la DPC fue de 53,4%, siendo mayor en aquellos con Cáncer de ampolla de Váter. Conclusiones: El cáncer de páncreas demuestra mayor agresividad a los 3 años de la DCP en comparación a los otros tipos de Cáncer Periampular. Pacientes en estadío IV de Cáncer de páncreas y duodeno fueron sometidos a DPC, estableciéndose éste diagnóstico en el post operatorio. : Más de la mitad de los pacientes sometidos a DPC en el INEN por Cáncer Periampular, durante los 10 años de estudio, estuvo vivo a los 3 años de la cirugía, esta supervivencia es menor en el cáncer de páncreas y mayor en el de ampolla de Váter.

Background: Psoas abscess is a rare clinical disease of various origins. Most common causes include hematogenous spread of bacteria from a different primary source, spondylodiscitis or perforated intestinal organs. But rarely some abscesses are related to malignant metastatic disease. Case presentation: In this case report we present the case of a patient with known squamous cell carcinoma of the cervix treated with radio-chemotherapy three years prior. She now presented with a psoas abscess and subsequent complete inferior vena cava thrombosis, as well as duodenal and vertebral infiltration. The abscess was drained over a prolonged period of time and later was found to be a complication caused by metastases of the cervical carcinoma. Due to the massive extent of the metastases a Whipple procedure was performed to successfully control the local progress of the metastasis. Conclusion: As psoas abscess is an unspecific disease which presents with non-specific symptoms adequate therapy may be delayed due to lack of early diagnostic results. This case report highlights the difficulties of managing a malignant abscess and demonstrates some diagnostic pitfalls that might be encountered. It stresses the necessity of adequate diagnostics to initiate successful therapy. Reports on psoas abscesses that are related to cervix carcinoma are scarce, probably due to the rarity of this event, and are limited to very few case reports. We are the first to report a case in which an extensive and complex abdominal procedure was needed for local control to improve quality of life.

No description available.

Thesis (M.A.)--Brigham Young University. Dept. of English, 2007. / Includes bibliographical references (p. 121-126).

Approved for public release; distribution in unlimited. / The International Space Station (ISS) must be able to withstand the hypervelocity impacts of micrometeoroids and orbital debris that strike its many surfaces. In order to design and implement shielding which will prevent hull penetration or other operational losses, NASA must first model the orbital debris and micrometeoroid environment. Based upon this environment, special multi-stage shields called Whipple and Enhanced Stuffed Whipple Shields are developed and implemented to protect ISS surfaces. Ballistic limit curves that establish shield failure criteria are determined via ground testing. These curves are functions of material strength, shield spacing, projectile size, shape and density, as well as a number of other variables. The combination of debris model and ballistic limit equations allows NASA to model risk to ISS using a hydro-code called BUMPER. This thesis modifies and refines existing ballistic limit equations for U.S. Laboratory Module shields to account for the effects of projectile (debris/ micro-meteoroid) densities. Using these refined ballistic limit equations this thesis also examines alternative shielding materials and configurations to optimize shield design for minimum mass and maximum stopping potential, proposing alternate shield designs for future NASA ground testing. A final goal of this thesis is to provide the Department of Defense a background in satellite shield theory and design in order to improve protection against micrometeoroid and orbital debris impacts on future spacebased national systems. / Lieutenant, United States Navy

Background: Psoas abscess is a rare clinical disease of various origins. Most common causes include hematogenous spread of bacteria from a different primary source, spondylodiscitis or perforated intestinal organs. But rarely some abscesses are related to malignant metastatic disease. Case presentation: In this case report we present the case of a patient with known squamous cell carcinoma of the cervix treated with radio-chemotherapy three years prior. She now presented with a psoas abscess and subsequent complete inferior vena cava thrombosis, as well as duodenal and vertebral infiltration. The abscess was drained over a prolonged period of time and later was found to be a complication caused by metastases of the cervical carcinoma. Due to the massive extent of the metastases a Whipple procedure was performed to successfully control the local progress of the metastasis. Conclusion: As psoas abscess is an unspecific disease which presents with non-specific symptoms adequate therapy may be delayed due to lack of early diagnostic results. This case report highlights the difficulties of managing a malignant abscess and demonstrates some diagnostic pitfalls that might be encountered. It stresses the necessity of adequate diagnostics to initiate successful therapy. Reports on psoas abscesses that are related to cervix carcinoma are scarce, probably due to the rarity of this event, and are limited to very few case reports. We are the first to report a case in which an extensive and complex abdominal procedure was needed for local control to improve quality of life.

La maladie de Whipple (MW) est une maladie infectieuse rare, sévère et chronique qui ne touche qu’une minorité d’individus infectés par Tropheryma whipplei (T. whipplei). Le portage chronique et asymptomatique de T. whipplei est moins rare. La pathogénie de la MW reste largement inconnue. Par une approche génétique combinant une analyse de liaison du génome entier et le séquençage de l’ensemble des exons, nous avons testé l’hypothèse d’une prédisposition génétique à la MW. Nous avons étudié une famille multiplexe comprenant quatre patients atteints de la MW mais n’ayant pas d’autres pathologies associées et cinq porteurs asymptomatiques de T. whipplei, pour laquelle nous avons envisagé un modèle autosomique dominant (AD) avec une pénétrance incomplète liée à l’âge. Nous avons montré que la mutation c.292 C>T (p.R98W) dans le gène IRF4 était le seul variant hétérozygote très rare et non-synonyme commun aux quatre patients. Chez la souris, le gène Irf4 est un facteur de transcription qui joue un rôle pléiotrope dans l’immunité. La caractérisation moléculaire de l’allèle muté a montré un effet délétère par un mécanisme d’haplo-insuffisance pour la fonction de facteur de transcription de la protéine. Une augmentation de la localisation cytoplasmique de la protéine a également été observée. De plus, le défaut IRF4 étudié confère une réponse transcriptomique distincte dans les leucocytes stimulés par le BCG ou T. whipplei. En conclusion, nous avons identifié la première étiologie génétique associée à la MW. Le mode d’hérédité est AD avec une pénétrance incomplète, le portage chronique précédant probablement la MW de plusieurs décennies chez les individus hétérozygotes infectés par T. whipplei. Ces travaux permettront de mieux comprendre la pathogénie de la MW, de mieux définir les mécanismes de l’immunité contre T. whipplei et de pouvoir offrir un diagnostic moléculaire et génétique adapté aux familles. / Whipple's disease (WD) is a rare, severe and chronic infectious disease that affects only a small minority of individuals infected with Tropheryma whipplei (T. whipplei). The chronic and asymptomatic carriage of T. whipplei is less rare. The pathogenesis of WD remains largely unknown. Using a genetic approach combining genome-wide linkage and whole exon sequencing, we tested the hypothesis of a genetic predisposition to WD. We studied a multiplex family containing four otherwise healthy WD patients and five asymptomatic T. whipplei carriers. We tested the hypothesis that WD follows autosomal dominant (AD) inheritance with age-dependent incomplete penetrance. We showed that the c.292 C> T mutation (p.R98W) of IRF4 gene was the only heterozygote variant that was very rare and non-synonymous for all four patients. In mice, the Irf4 gene is a transcription factor that plays pleiotropic roles in immunity. Molecular characterization of the mutated allele showed a deleterious effect by a haplo-insufficiency mechanism for the transcription factor function of the protein. Increase localization of the protein in the cytoplasmic has also been observed. In addition, the defect IRF4 studied confers a distinct transcriptomic response in leukocytes stimulated by BCG or T. whipplei. In conclusion, we identified the first genetic etiology associated with WD. The mode of inheritance is AD with incomplete penetrance, chronic carriage probably preceding WD for several decades in heterozygous individuals infected with T. whipplei. This work will help to better understand the pathogenesis of WD, to better define the mechanisms of immunity against T. whipplei and to be able to offer a molecular and genetic adapted diagnosis to families.

In this thesis we investigate the problem of designing a control system for a modern bicycle so that the bicycle is stable and follows a path. We propose a multi-loop control architecture, where each loop is systematically designed using linear control techniques. The proposed strategy guarantees that the bicycle asymptotically converges to paths of constant curvature. A key advantage of our approach is that by using linear techniques analysis and controller design are relatively simple. We base our control design on the nonlinear (corrected) Whipple model, which has been previously verified for correctness and experimentally validated. The equations of motion for the nonlinear model are very complicated, and would take many pages to explicitly state. They also have no known closed form solution. To enable analysis of the model we linearize it about a trajectory such that the bicycle is upright and travelling straight ahead. This linearization allows us to arrive at a parameterized linear time-invariant state-space representation of the bicycle dynamics, suitable for analysis and control design. The inner-loop control consists of a forward-speed controller as well as a lean and steer controller. To keep the bicycle at a constant forward speed, we develop a high-bandwidth proportional controller that uses a torque along the axis of the rear wheel of the bicycle to keep the angular velocity of the rear wheel at a constant setpoint. To stabilize the bicycle at this forward speed, lean torque and steer torque are treated as the control signals. We design a state-feedback controller and augment integrators to the output feedback of the lean angle and steer angle to provide perfect steady-state tracking. To arrive at the gains for state feedback, linear-quadratic regulator methods are used. When following a constant-curvature path, a vehicle has a constant yaw rate. Using this knowledge, we begin designing the outer-loop path-following control by finding a map that converts a yaw rate into appropriate lean angle and steer angle references for the inner loop. After the map is completed, system identification is performed by applying a yaw-rate reference to the map and analyzing the response of the bicycle. Using the linear approximation obtained, a classical feedback controller for yaw-rate tracking is designed. In addition to yaw-rate control, to track a path the yaw angle of the bicycle must match that of the path and the bicycle must physically be on the path. To analyze these conditions a linear approximation for the distance between the bicycle to the path is found, enabling construction of a linear approximation of the entire system. We then find that by passing the signal for the difference in yaw rate and the distance through separate controllers, summing their output, and subtracting from the reference yaw rate of the path, the bicycle converges to the path. After developing the general design procedure, the final part of the thesis shows a step by step design example and demonstrates the results of applying the proposed control architecture to the nonlinear bicycle model. We highlight some problems that can arise when the bicycle is started far from the path. To overcome these problems we develop the concept of a virtual path, which is a path that when followed returns the bicycle to the actual path. We also recognize that, in practice, typical paths do not have constant curvature, so we construct more practical paths by joining straight line segments and circular arc segments, representing a practical path similar to a path that would be encountered when biking through a series of rural roads. Finally, we finish the design example by demonstrating the performance of the control architecture on such a path. From these simulations we show that using the suggested controller design that the bicycle will converge to a constant curvature path. Additionally with using the controllers we develop that in the absence of disturbance the bicycle will stay within the intended traffic lane when travelling on a typical rural road.

Thèse d'exercice : Médecine. Médecine générale : Paris 12 : 2005. / Titre provenant de l'écran-titre. Bibliogr. f. 114-131.

In this thesis we investigate the problem of designing a control system for a modern bicycle so that the bicycle is stable and follows a path. We propose a multi-loop control architecture, where each loop is systematically designed using linear control techniques. The proposed strategy guarantees that the bicycle asymptotically converges to paths of constant curvature. A key advantage of our approach is that by using linear techniques analysis and controller design are relatively simple. We base our control design on the nonlinear (corrected) Whipple model, which has been previously verified for correctness and experimentally validated. The equations of motion for the nonlinear model are very complicated, and would take many pages to explicitly state. They also have no known closed form solution. To enable analysis of the model we linearize it about a trajectory such that the bicycle is upright and travelling straight ahead. This linearization allows us to arrive at a parameterized linear time-invariant state-space representation of the bicycle dynamics, suitable for analysis and control design. The inner-loop control consists of a forward-speed controller as well as a lean and steer controller. To keep the bicycle at a constant forward speed, we develop a high-bandwidth proportional controller that uses a torque along the axis of the rear wheel of the bicycle to keep the angular velocity of the rear wheel at a constant setpoint. To stabilize the bicycle at this forward speed, lean torque and steer torque are treated as the control signals. We design a state-feedback controller and augment integrators to the output feedback of the lean angle and steer angle to provide perfect steady-state tracking. To arrive at the gains for state feedback, linear-quadratic regulator methods are used. When following a constant-curvature path, a vehicle has a constant yaw rate. Using this knowledge, we begin designing the outer-loop path-following control by finding a map that converts a yaw rate into appropriate lean angle and steer angle references for the inner loop. After the map is completed, system identification is performed by applying a yaw-rate reference to the map and analyzing the response of the bicycle. Using the linear approximation obtained, a classical feedback controller for yaw-rate tracking is designed. In addition to yaw-rate control, to track a path the yaw angle of the bicycle must match that of the path and the bicycle must physically be on the path. To analyze these conditions a linear approximation for the distance between the bicycle to the path is found, enabling construction of a linear approximation of the entire system. We then find that by passing the signal for the difference in yaw rate and the distance through separate controllers, summing their output, and subtracting from the reference yaw rate of the path, the bicycle converges to the path. After developing the general design procedure, the final part of the thesis shows a step by step design example and demonstrates the results of applying the proposed control architecture to the nonlinear bicycle model. We highlight some problems that can arise when the bicycle is started far from the path. To overcome these problems we develop the concept of a virtual path, which is a path that when followed returns the bicycle to the actual path. We also recognize that, in practice, typical paths do not have constant curvature, so we construct more practical paths by joining straight line segments and circular arc segments, representing a practical path similar to a path that would be encountered when biking through a series of rural roads. Finally, we finish the design example by demonstrating the performance of the control architecture on such a path. From these simulations we show that using the suggested controller design that the bicycle will converge to a constant curvature path. Additionally with using the controllers we develop that in the absence of disturbance the bicycle will stay within the intended traffic lane when travelling on a typical rural road.