Actualización sobre apnea obstructiva del sueño en la etapa de movimientos oculares rápidos

La apnea obstructiva del sueño durante los movimientos oculares rápidos del sueño (AOS REM), se define como la presencia de episodios de apnea y/o hipopnea obstructivos en la etapa del sueño REM. La epidemiología de esta patología es compleja y no existe una definición estandarizada actualmente. Aunque no se ha logrado llegar a un consenso para definir AOS REM, la evidencia señala que está asociada a factores de riesgos cardiovasculares, metabólicos y neurocognitivos de forma independiente. A pesar que su tratamiento principal es la presión positiva continua de las vías respiratorias (CPAP), los criterios de un adecuado uso de CPAP en la AOS, no son suficientes para tratar de forma adecuada la AOS REM. Es necesario estandarizar una definición universal y realizar estudios prospectivos diseñados para buscar estrategias de tratamientos específicos para la AOS REM.

Obstructive sleep apnea during rapid eye movement sleep (REM OSA) is defined as the presence of obstructive episodes of apnea and/or hypopnea in REM sleep. The epidemiology of this pathology is complex and there is currently no standardized definition. Although no consensus has been reached to define REM OSA, the evidence indicates that it is independently associated with cardiovascular, metabolic and neurocognitive risk factors. Although its main treatment is continuous positive airway pressure (CPAP), the criteria for an adequate use of CPAP in OSA are not sufficient to adequately treat REM OSA. It is necessary to standardize a universal definition and carry out prospective studies designed to search for specific treatment strategies for REM OSA.

Adenoma pleomórfico del espacio parafaríngeo: una entidad escondida / Pleomorphic adenoma of the parapharyngeal space: a hidden entity

Resumen Los tumores del espacio parafaríngeo son poco frecuentes. Dentro de ellos, las neoplasias benignas son las más frecuentes, destacando principalmente los adenomas pleomorfos. Estos tumores suelen permanecer asintomáticos hasta alcanzar el tamaño suficiente para producir alteraciones debido al efecto de masa. A pesar de su naturaleza benigna, es necesario realizar resección completa dada su alta tasa de recurrencia y potencial de transformación maligna. Presentamos el caso de un paciente de 52 años que en estudio de vértigo se detecta incidentalmente una masa tumoral del espacio parafaríngeo de 45 mm × 32 mm de diámetro, de etiología incierta. Se realizó una biopsia incisional endoscópica que evidenció un adenoma pleomórfico, que actualmente se encuentra en etapa de evaluación y planificación de escisión completa. En conclusión, dado que los hallazgos clínicos y radiológicos no siempre son suficientes para determinar la naturaleza de las lesiones del espacio parafaríngeo, es importante contar con un diagnóstico histológico. Los avances en las técnicas de cirugía endoscópica sinusal han permitido acceder a esta zona con una mínima morbilidad y estadía hospitalaria. Debido a la posibilidad de transformación maligna los adenomas pleomórficos requieren un manejo activo.

Abstract Tumors of the parapharyngeal space are rare. Benign neoplasms are the most frequent and, among them, pleomorphic adenomas stand out. These tumors are usually asymptomatic until they reach a size large enough to produce symptoms due to mass effect. Despite its benign nature, it is necessary to perform a complete resection given its high recurrence rate and its potential for malignant transformation. We present the case of a 52-year-old man in whom a study of vertigo incidentally detected a mass in the parapharyngeal space measuring 45 mm × 32 mm in diameter, of unknown etiology. An endoscopic incisional biopsy was performed, showing a pleomorphic adenoma, which is currently under assessment to plan complete removal. In conclusion, as clinical and radiological findings are not always sufficient to determine the nature of parapharyngeal space lesions, it is important to obtain a histological diagnosis. Advances in endoscopic sinus surgery techniques have allowed access to this area with minimal morbidity and hospital stay. Due to the possibility of malignant transformation pleomorphic adenomas require active management.

Fabrication of Silver Nanoparticles Using a Gas Phase Nanocluster Device and Preliminary Biological Uses.

Nanoparticles can be used in a large variety of applications, including magnetic sensing, biological, superconductivity, tissue engineering, and other fields. In this study, we explore the fabrication of gas phase silver nanoparticles using a sputtering evaporation source. This setup composed of a dual magnetron cluster source holds several advantages over other techniques. The system has independent control over the cluster concentration and a wide range of cluster size and materials that can be used for the clusters and for the matrix where it can be embedded. Characterization of these silver nanoparticles was done using transmission electron microscopy (TEM). We obtain a lateral width of 10.6 nm with a dispersion of 0.24 nm. With atomic force microscopy (AFM) a Gaussian fit of this distribution yields and average height of 6.3 nm with a standard deviation of 1.4 nm. We confirm that the deposited silver nanoparticles have a homogenous area distribution, that they have a defined shape and size distribution, and that they are single standing nanoparticles. Given that the scientific literature is not precise regarding the toxic concentration of the nanoparticles, devices such as ours can help clarify these questions. In order to explore further biological applications, we have done preliminary experiments of cell spreading (myoblast adhesion), obtaining interesting morphological changes correlated with the silver concentration on the surface. With a deposited silver concentration ranging from 100⁻620 ng/cm², the cells showed morphological changes in a short time of 2 h. We conclude that this high precision nanoparticle fabrication technique is adequate for further biological research.

Influence of urban pattern on inundation flow in floodplains of lowland rivers.

The objective of this paper is to investigate the respective influence of various urban pattern characteristics on inundation flow. A set of 2000 synthetic urban patterns were generated using an urban procedural model providing locations and shapes of streets and buildings over a square domain of 1×1km2. Steady two-dimensional hydraulic computations were performed over the 2000 urban patterns with identical hydraulic boundary conditions. To run such a large amount of simulations, the computational efficiency of the hydraulic model was improved by using an anisotropic porosity model. This model computes on relatively coarse computational cells, but preserves information from the detailed topographic data through porosity parameters. Relationships between urban characteristics and the computed inundation water depths have been based on multiple linear regressions. Finally, a simple mechanistic model based on two district-scale porosity parameters, combining several urban characteristics, is shown to capture satisfactorily the influence of urban characteristics on inundation water depths. The findings of this study give guidelines for more flood-resilient urban planning.

Synergistic effect of high hydrostatic pressure and natural antimicrobials on inactivation kinetics of Bacillus cereus in a liquid whole egg and skim milk mixed beverage.

An in-depth study was conducted in order to extend the storage life of a liquid whole egg-skim milk (LWE-SM) mixed beverage to enhance its safety and the safety of related beverages. Bacillus cereus vegetative cells (1 x 10(8) colony-forming units [CFU]/mL) were inoculated in LWE-SM beverages with or without natural antimicrobial supplements: flavonol rich-cocoa powder (cocoanOX 12%, CCX) (700 ppm), vanillin (700 ppm), anise (700 ppm), and cinnamon (700 ppm). B. cereus cells were maintained at 10 degrees C for 10 days in the different beverages to test the bacteriostatic or inhibitory effect of the aforementioned ingredients. Beverages were treated with high hydrostatic pressure (HHP) technology and stored at 10 degrees C for 15 days after treatment. All natural antimicrobials reduced the micro(max) values and increased the lag phase time of B. cereus, and Gompertz growth curves showed different inhibitory effects depending on the substance. The maximum inhibitory effect (1.330 log cycle reduction) was achieved in LWE-SM-cinnamon-supplemented beverage. The maximum inactivation achieved by HHP in LWE-SM beverage was a reduction of around 3.89 +/- 0.25 log cycles at 300 MPa for 12 minutes. When supplemented beverages were treated under the same conditions, enhanced inactivation levels were achieved. This increased inactivation can be attributed to a synergistic effect when the LWE-SM was supplemented with flavonol-rich cocoa powder, cinnamon, and vanillin. The maximum synergistic effect was observed in LWE-SM-CCX-supplemented beverage. During the refrigerated storage of B. cereus HHP-treated cells in beverages to which antimicrobials had been added, the inhibitory effect was dependent on the previously applied pressure level.

Pressure inactivation kinetics of Enterobacter sakazakii in infant formula milk.

Survival curves of Enterobacter sakazakii inactivated by high hydrostatic pressure were obtained at four pressure levels (250, 300, 350, and 400 MPa), at temperatures below 30 degrees C, in buffered peptone water (BPW; 0.3%, wt/vol) and infant formula milk (IFM; 16%, wt/vol). A linear model and four nonlinear models (Weibull, log-logistic, modified Gompertz, and Baranyi) were fitted to the data, and the performances of the models were compared. The linear regression model for the survival curves in BPW and IFM at 250 MPa has fitted regression coefficient (R2) values of 0.940 to 0.700, respectively, and root mean square errors (RMSEs) of 0.770 to 0.370. For the other pressure levels, the linear regression function was not appropriate, as there was a strong curvature in the plotted data. The nonlinear regression models with the log-logistic and modified Gompertz equations had R2 values of 0.960 to 0.992 and RMSE values of 0.020 to 0.130 within pressure levels of 250 to 400 MPa, respectively. These results indicate that they are both better models for describing the pressure inactivation kinetics of E. sakazakii in IFM and BPW than the Weibull distribution function, which has an R2 minimum value of 0.832 and an RMSE maximum value of 0.650 at 400 MPa. On the other hand, the parameters for the Weibull distribution function, log-logistic model, and modified Gompertz equation did not have a clear dependence on pressure. The Baranyi model was also analyzed, and it was concluded that this model provided a reasonably good fit and could be used to develop predictions of survival data at pressures other than the experimental pressure levels in the range studied. The results provide accurate predictions of survival curves at different pressure levels and will be beneficial to the food industry in selecting optimum combinations of pressure and time to obtain desired target levels of E. sakazakii inactivation in IFM.

Cirugía laparoscópica en lesiones anexiales / Laparoscopic surgery in adnexal injuries

Noventa y dos pacientes con diagnóstico de lesión anexial seleccionadas por su examen clínico, de ultrasonografía y de CA-125, fueron operadas por laparoscopia por los autores, entre julio de 1994 y julio de 1999 en el Departamento de Obstetricia y Ginecología del Hospital Clínico de la Universidad de Chile. Su edad promedio fue de 38 años con un rango de 18-75 años. Veintidos pacientes (24 por ciento) eran postmenopaúsicas, 24 (26 por ciento) obesas y 45 (49 por ciento) tenían cirugía abdominal previa. El tiempo quirúrgico promedio fue de 69 minutos (rango 20-180 min) y el promedio de días de hospitalización fue de 1,2 días con un rango de < 1 a 4 días. Hubo el hallazgo de un cáncer (1,1 por ciento), resultó de una anexectomía con adherencias en que se abrió la vejiga accidentalmente sin lograr repararla en forma satisfactoria por laparoscopia, debiendo hacerse por laparotomía. No hubo otras complicaciones intraoperatorias ni postoperatorias. En conclusión la cirugía laparoscópica es un procedimiento seguro y de muy baja morbilidad para el tratamiento de pacientes con el diagnóstico de lesión anexial que han sido seleccionadas por criterios clínicos y de ultrasonografía. En las pacientes postmenopáusicas debe complementarse el estudio con el CA-125. En las pacientes que no reunen los criterios de benignidad mencionados, la laparoscopia evita la laparotomía en un número importante de casos en que las lesiones son benignas, teniendo la precaución de tratarlas en centros especializados para un manejo adecuado en caso de encontrarse una lesión maligna