[Development, techniques, and utility of experimental animal models of thoracic and abdominal aortic aneurysms]. / Desarrollo, técnicas y utilidad de modelos animales experimentales de aneurismas aórticos torácicos y abdominales.

Aneurysms are clinical entities that can develop and affect human aorta; and although in most cases they have an asymptomatic course, these pathological dilatations can lead to a lethal outcome when rupture occurs, thus the establishment of predictors is crucial for death prevention. Essential events that take place in the vessel wall have been identified and described, such as inflammation, proteolysis, smooth muscle cell apoptosis, angiogenesis, and vascular remodeling. Porcine and ovine models have been useful for the development and evaluation of endovascular devices of the aorta. However, since the worldwide introduction and adoption of these minimally invasive techniques for aneurysm repair, there is lesser availability of diseased aortic tissue for molecular, cellular, and histopathological analysis, therefore over the last three decades it has been proposed various small species models that have allowed the focal induction of these lesions for the study of physiopathological mechanisms and possible useful biomarkers as diagnostic and therapeutic targets. The present review article presents and discusses the animal models available as their applications, characteristics, advantages, and limitations for the development of preclinical studies, and their importance in the comprehension of this pathology in humans.

Los aneurismas son una de las entidades clínicas que pueden desarrollarse y afectar la aorta humana. Aunque en la mayoría de los casos tienen un carácter asintomático, estas dilataciones patológicas pueden resultar letales cuando se presentan con ruptura, por lo que el reconocimiento de factores predictores de esta complicación es crucial para evitar muertes. Fisiopatológicamente se han identificado eventos esenciales que ocurren en la pared del vaso, como inflamación, proteólisis, apoptosis del músculo liso, angiogénesis y remodelación. Las grandes especies como porcinos y ovinos han sido de utilidad para el desarrollo y evaluación del desempeño de dispositivos endovasculares en la aorta, así como la remodelación; con el advenimiento y disposición de estas técnicas mínimamente invasivas para su reparación existe una menor disponibilidad de tejido aórtico para el análisis molecular, celular e histopatológico, por lo que en las últimas tres décadas se han propuesto e introducido distintos modelos que han permitido, mediante la inducción focal de estas lesiones, el estudio de los mecanismos fisiopatológicos y posibles biomarcadores de utilidad como dianas diagnósticas y terapéuticas. El presente artículo de revisión aborda tipos de modelos animales disponibles, así como sus aplicaciones, consideraciones, ventajas y limitaciones para el desarrollo de estudios preclínicos y su importancia en el entendimiento de esta patología en la especie humana.

Water content monitoring in water-in-oil emulsions using a delay line cell.

The extraction process of crude oil requires addition of water, resulting in complex emulsions, in which the phases must be separated before the petrochemical processing starts. An ultrasonic cell may be used to determine in real time the water content in water-in-crude oil emulsions. The water content of emulsions can be related to parameters, such as propagation velocity, density and relative attenuation. The ultrasonic measurement cell developed here is composed of two piezoelectric transducers, two rexolite buffer rods, and a sample chamber. It is an inexpensive and robust system. The cell measures the parameters at different temperatures and flow conditions. The tests were performed using emulsions with water volume concentrations from 0% to 40%. The experimental results show that this cell is able to obtain more precise parameters, when compared to similar ultrasonic techniques. The data acquired in real time may be used to improve the emulsion separation, decreasing greenhouse gases and energy requirements.

Baculovirus-mediated expression of a Helicobacter pylori protein-based multiepitope hybrid gene induces a potent B cell response in mice.

Helicobacter pylori is a gram-negative bacterium that is present in over half of the world's population. The colonization of the stomach́s gastric mucosa by H. pylori is related to the onset of chronic gastritis, peptic ulcer, and cancer. The estimated deaths from gastric cancer caused by this bacterial infection are in the 15,000-150,000 range. Current treatment for controlling the colonization of H. pylori includes the administration of two to four antibiotics and a gastric ATPase proton pump inhibitor. Nevertheless, the bacterium has shown increased resistance to antibiotics. Despite an extensive list of attempts to develop a vaccine, no approved vaccine against H. pylori is available. Recombinant viruses are a novel alternative for the control of primary pathogenic agents. In this work, we employed a baculovirus that carries a Thp1 transgene coding for nine H. pylori epitopes, some from the literature, and others were selected in silico from the sequence of H. pylori proteins (carbonic anhydrase, urease B subunit, gamma-glutamyl transpeptidase, Lpp20, Cag7, and CagL). We verified the expression of this hybrid multiepitopic protein in HeLa cells. Mice were inoculated with the recombinant baculovirus Bac-Thp1 using various administration routes: intranasal, intragastric, intramuscular, and a combination of intranasal and intragastric. We identified a strong adjuvant-independent IgG-antibody response in the serum of recombinant baculovirus-Thp1 inoculated mice, which was specific for a strain of H. pylori isolated from a human patient. The bacterium-specific IgG-antibodies were present in sera 125 days after the first vaccine administration. Also, H. pylori-specific IgA-antibodies were found in feces at 82 days after the first inoculation. A baculovirus-based vaccine for H. pylori is promising for controlling this pathogen in humans.

Ultrasonic Monitoring of the Water Content in Concentrated Water-Petroleum Emulsions Using the Slope of the Phase Spectrum.

This work proposes the slope of the phase spectrum as a signal processing parameter for the ultrasonic monitoring of the water content of water-in-crude oil emulsions. Experimental measurements, with water volume fractions from 0 to 0.48 and test temperatures of 20 °C, 25 °C, and 30 °C, were carried out using ultrasonic measurement devices operating in transmission-reception and backscattering modes. The results show the phase slope depends on the water volume fraction and, to a lesser extent, on the size of the emulsion droplets, leading to a stable behavior over time. Conversely, the behavior of the phase slope as a function of the volume fraction is monotonic with low dispersion. Fitting a power function to the experimental data provides calibration curves that can be used to determine the water content with percentage relative error up to 70% for a water volume fraction of 0.06, but less than 10% for water volume fractions greater than 0.06. Furthermore, the methodology works over a wide range of volume fractions.

Water Content Monitoring in Water-in-Crude-Oil Emulsions Using an Ultrasonic Multiple-Backscattering Sensor.

This work shows the application of an ultrasonic multiple-scattering sensor for monitoring water-in-petroleum emulsions. The sensor consists of a commercial ultrasonic transducer with an array of cylindrical scatterers placed in the near field. The scatterers are thin metal bars arranged in rows in front of the transducer. The backscattering signals were analyzed by calculating the wave energy and by a cross-correlation between signal segments; they were also used to determine the propagation velocity in the emulsions. The tests performed used emulsions with water volume concentrations from 0% to 50%. The results showed that both the signal energy and propagation velocity strongly depended on the concentration of water in the emulsion. Therefore, the ultrasonic multiple-scattering sensor can be used for on-line and real-time monitoring of the water content in water-in-crude-oil emulsions.

Loss of Znt8 function in diabetes mellitus: risk or benefit?

The zinc transporter 8 (ZnT8) plays an essential role in zinc homeostasis inside pancreatic ß cells, its function is related to the stabilization of insulin hexameric form. Genome-wide association studies (GWAS) have established a positive and negative relationship of ZnT8 variants with type 2 diabetes mellitus (T2DM), exposing a dual and controversial role. The first hypotheses about its role in T2DM indicated a higher risk of developing T2DM for loss of function; nevertheless, recent GWAS of ZnT8 loss-of-function mutations in humans have shown protection against T2DM. With regard to the ZnT8 role in T2DM, most studies have focused on rodent models and common high-risk variants; however, considerable differences between human and rodent models have been found and the new approaches have included lower-frequency variants as a tool to clarify gene functions, allowing a better understanding of the disease and offering possible therapeutic targets. Therefore, this review will discuss the physiological effects of the ZnT8 variants associated with a major and lower risk of T2DM, emphasizing the low- and rare-frequency variants.

Brown tumor of the cervical spine in a patient with secondary hyperparathyroidism: A case report.

INTRODUCTION: Brown tumors are non-neoplastic, expansive bone lesions that occur only in the setting of hyperparathyroidism. The most usual localization of brown tumors is in mandible, ribs and large bones. In cervical spine, to date, there are only 11 cases reported. The aim of this work is to report the case of a patient with Wegener´s granulomatosis with secondary end stage renal failure who developed a brown tumor in C4 vertebra. PRESENTATION OF CASE: A 25-year-old woman with an history of 2 months of worsening cervicalgia without history of trauma. She complained about progressive neck pain with irradiation to both shoulders and right arm paresthesias, spontaneous fracture or brown spinal cord tumor were suspected. She presented cervical spine instability, was managed with corpectomy of C4 and biopsy. DISCUSSION: The initial suspicion of this disease must be since the first clinician contact of the patient and with the past medical history of end stage renal failure plus recent neurologic manifestations. The aim of neurosurgical management of these patients is to promote spinal stability and release spinal cord and nerve roots to eliminate risk of neurological deficits. CONCLUSION: The importance of the prompt diagnosis of the brown tumor is to establish a multidisciplinary management to prevent progression, neurologic complications and sequelae despite its benign behavior.

Anaplasic astrocytoma with exophytic growth in Sylvian fissure in a pediatric patient: a case report.

Gliomas are the most frequent supratentorial intracranial tumors in the pediatric population. Usually, they are intra-axial lesions with a characteristic image pattern, however, there are few reported cases of gliomas with exophytic growth. There are no previous reports in the literature of gliomas with exophytic growth in the Sylvian fissure. Fourteen year-old female patient who started with seizures. In imaging studies, a neoplasic mass with an exophytic portion in the left Sylvian fissure was found. Macroscopically, total resection was performed, definitive diagnosis was anaplastic astrocytoma. She presented recurrence and is currently receiving adjuvant treatment. Supratentorial gliomas with exophytic growth are extremely rare. We report the first case in the pediatric population, and we consider it is important to know its imaging and macroscopic characteristics for its initial management and to take it into account as a differential diagnosis of exophytic lesions.

Estrés emocional en estudiantes de Medicina de la Universidad Nacional Autónoma de México / Emotional stress in medical students from the National Autonomous University of Mexico

El presente estudio se realizó con el objetivo de evaluar el impacto del estrés emocional en la adecuada toma de decisiones y práctica médica oportuna y de calidad de los estudiantes que cursan el quinto año de la carrera en la Facultad de Medicina de la Universidad Nacional Autónoma de México (UNAM). Se utilizó una lista de valoración para las competencias de la simulación de reanimación cardiopulmonar avanzada, y un Cuestionario de Maslach Burnout Inventory (MBI) para valorar los sentimientos, actitudes y de desgaste profesional. Los resultados muestran que aquellos que estaban expuestos a mayor cantidad de labores recientes y estrés fueron más propensos de incidir en errores médicos durante la toma de decisiones y su aprendizaje.

This study was conducted with the aim of assessing the impact of emotional stress in the appropriate decision-making and quality medical practice of fifth year medical students from the Faculty of Medicine of the National Autonomous University of Mexico (UNAM). It was used an assessment list for cardiopulmonary resuscitation simulation competence and a Maslach Burnout Inventory (MBI) Questionnaire was used to assess feelings, attitudes and professional wear and tear. Results show those who were exposed to a greater number of recent tasks and to greater stress were more likely to make medical mistakes while making decisions and learning.

Real-time resolution of point mutations that cause phenovariance in mice.

With the wide availability of massively parallel sequencing technologies, genetic mapping has become the rate limiting step in mammalian forward genetics. Here we introduce a method for real-time identification of N-ethyl-N-nitrosourea-induced mutations that cause phenotypes in mice. All mutations are identified by whole exome G1 progenitor sequencing and their zygosity is established in G2/G3 mice before phenotypic assessment. Quantitative and qualitative traits, including lethal effects, in single or multiple combined pedigrees are then analyzed with Linkage Analyzer, a software program that detects significant linkage between individual mutations and aberrant phenotypic scores and presents processed data as Manhattan plots. As multiple alleles of genes are acquired through mutagenesis, pooled "superpedigrees" are created to analyze the effects. Our method is distinguished from conventional forward genetic methods because it permits (1) unbiased declaration of mappable phenotypes, including those that are incompletely penetrant (2), automated identification of causative mutations concurrent with phenotypic screening, without the need to outcross mutant mice to another strain and backcross them, and (3) exclusion of genes not involved in phenotypes of interest. We validated our approach and Linkage Analyzer for the identification of 47 mutations in 45 previously known genes causative for adaptive immune phenotypes; our analysis also implicated 474 genes not previously associated with immune function. The method described here permits forward genetic analysis in mice, limited only by the rates of mutant production and screening.

Learning curve in a Western training center of the circumferential en bloc esophageal endoscopic submucosal dissection in an in vivo animal model.

Aim. Evaluate the feasibility to overcome the learning curve in a western training center of the en bloc circumferential esophageal (ECE-) ESD in an in vivo animal model. Methods. ECE-ESD was performed on ten canine models under general anesthesia on artificial lesions at the esophagus marked with coagulation points. After the ESD each canine model was euthanized and surgical resection of the esophagus and stomach was carried out according to "the Principles of Humane Experimental Technique, Russel and Burch." The specimen was fixed with needles on cork submerged in formalin with the esophagus and stomach then delivered to the pathology department to be analyzed. Results. ECE-ESD was completed without complications in the last 3/10 animal models. Mean duration for the procedures was 192 ± 35 minutes (range 140-235 minutes). All the procedures were done at the animal lab surgery room with cardio pulmonary monitoring and artificial ventilation by staff surgery members and a staff member of the Gastroenterology department trained during 1999-2001 at the Fujigaoka hospital of the Showa U. in Yokohama, Japan, length (range 15-18 mm) and 51 ± 6.99 width (range 40-60 mm). Conclusion. ECE-ESD training is feasible in canine models for postgraduate endoscopy fellows.

Endoscopic submucosal dissection in dogs in a World Gastroenterology Organisation training center.

AIM: To evaluate if canine models are appropriate for teaching endoscopy fellows the techniques of endoscopic submucosal dissection (ESD). METHODS: ESD was performed in 10 canine models under general anesthesia, on artificial lesions of the esophagus or stomach marked with coagulation points. After ESD, each canine model was euthanized and surgical resection of the esophagus or stomach was carried out according to "The Principles of Humane Experimental Technique, Russel and Burch". The ESD specimens were fixed with needles on cork submerged in a formol solution with the esophagus or stomach, and delivered to the pathology department to be analyzed. RESULTS: ESD was completed without complications using the Hook-knife in five esophageal areas, with a procedural duration of 124 +/- 19 min, a length of 27.4 +/- 2.6 mm and a width of 21 +/- 2.4 mm. ESD was also completed without complications using the IT-knife2 in five gastric areas, with a procedural duration of 92.6 +/- 19 min, a length of 32 +/- 2.5 mm and a width of 18 +/- 3.7 mm. CONCLUSION: ESD is feasible in the normal esophagus and stomach of canine models, which are appropriate for teaching this technique.

[The sedation role in upper digestive endoscopy]. / El rol de la sedación en la endoscopía digestiva alta.

OBJECTIVES: Determine the variation of the vital constants during endoscopy in the sedate and non-sedate patients. Evaluate the anxiety in the patient. Evaluate the doctor attitude at the procedure. Evaluate the patient satisfaction and inquire about the patient disposition to repeat in the future the procedure in the same conditions. METHODS: This is a prospective, descriptive, and double blind randomize comparative study with 197 patients subjected to upper digestive endoscopy, 101 received endovenous sedation and 96 local anesthesia. RESULTS: Sedation in upper digestive endoscopy showed a significant lower complaints perception (p<0.0001), pain, nausea and lack of air sensation (p<0.001) with a better endoscopist appraisal with respect the non sedated (p<0.015). The sedated patient had a significant decrease of his basal systolic and diastolic pressures (p<0.0001). Non sedated patient present a significant difficult endoscopy insertion at the first attempt (p<0.001). CONCLUSION: Upper digestive endoscopy with sedation was significantly better both for the doctor as for the patient in general well-being as in less pain, nausea and lack of air sensation. The most sedated patients agreed without doubts to repeat the exam if it was necessary.

El rol de la sedación en la endoscopía digestiva alta / The role of the sedation in the high digestive endoscopy

Objetivos: 1. Determinar la variación de las constantes vitales en el paciente sedado y no sedado 2. Evaluar la ansiedad del paciente 3. Evaluar el punto de vista médico 4. Evaluar la satisfacción del paciente 5. Ver la disposición del paciente a realizarse un nuevo examen en las mismas condiciones. Métodos: Se trata de un estudio clínico experimental prospectivo, de distribución al azar, comparativo a doble ciego. Se evaluaron a 197 pacientes a los cuales se le sometió a endoscopía digestiva alta, entre los meses de Enero a Julio del 2003, 101 recibieron sedación endovenosa y 96 solo anestesia tópica. Resultados: La sedación en la endoscopía presentó una significativa menor percepción de molestias (p menor 0.0001) dolor, naúsea y falta de aire (p menor 0.001); con una significativa mejor apreciación del endoscopista en relación al no sedado (p menor 0.015). Se encontró en los sedados una disminución significativa de la presión sistólica y diastólica (p menor 0.0001). En el no sedado se encontró una dificultad para realizar la inserción endoscópica al primer intento (p menor 0.001). Conclusión: La endoscopía digestiva alta con sedación demostró ser significativamente mejor tanto para el médico como para el paciente. Los pacientes que se realizaron endoscopía bajo sedación acudirían mayoritariamente a un nuevo examen si fuera necesario.

Objectives: 1.Determine the variation of the vital constants during endoscopy in the sedate and non-sedate patients. Evaluate the anxiety in the patient. Evaluate the doctor attitude at theprocedure. Evaluate the patient satisfaction and inquire about the patient disposition to repeat in the future the procedure in the same conditions. METHODS: This is a prospective, descriptive, and duoble blind randomize comparative studywith 197 patients subjected to upper digestive endoscopy, 101 received endovenous sedation and 96 local anesthesia. RESULTS. Sedation in upper digestive endoscopy showed a significant lower complaints perception(p<0.0001), pain, nausea and lack of air sensation (p<0.001) with a better endoscopist appraisal with respect the non sedated (p<0.015). The sedated patient had a significant decrease of his basal systolic and diastolic pressures (p<0.0001). Non sedated patient present a significant difficult endoscopy insertion at the first attempt (p<0.001).CONCLUSION: Upper digestive endoscopy with sedation was significantly better both for the doctor as for the patient in general well-being as in less pain, nausea and lack of air sensation. The most sedated patients agreed without doubts to repeat the exam if it was necessary.

La inseguridad en el Perú: índices e interpretaciones para los 90's / Insecurity in Peru: indexes and interpretations for the 90's

Análisis cuantitativo de la violencia en el Perú, en particular intenta elaborar un índice que ayude a medir los niveles de inseguridad del país, año por año y departamento por departamento

Reconstrucción fálica total: informe de un caso. Comunicación preliminar / Total reconstruction of the phallus: report of a case. preliminary communication

La reconstrucción total del falo es ahora técnicamente factible. Es posible la restauración de la función sexual en el paciente con el neofalo utilizando el colgajo neurosensorial radial del antebrazo. El neofalo inervado desarrolla sensasión táctil y erógena en seis a ocho meses después del procedimiento. En esta comunicación preliminar se informa la experiancia quirúrgica de los autores con una neofaloplastia con colgajo radial del antebrazo de un solo tiempo en un paciente joven de 18 años de edad, quien sufrió un traumatismo genital mecánico. Seis meses después de la intervención el congajo se encuentra bien integrado y con aspecto aceptable, y cuenta con una uretra completa funcional. Su prótesis peneana semirrígida experimentó extrusión, y se planea colocarle una prótesis insuflable