Prediction of daily mean and one-hour maximum PM2.5 concentrations and applications in Central Mexico using satellite-based machine-learning models.

BACKGROUND: Machine-learning algorithms are becoming popular techniques to predict ambient air PM2.5 concentrations at high spatial resolutions (1 × 1 km) using satellite-based aerosol optical depth (AOD). Most machine-learning models have aimed to predict 24 h-averaged PM2.5 concentrations (mean PM2.5) in high-income regions. Over Mexico, none have been developed to predict subdaily peak levels, such as the maximum daily 1-h concentration (max PM2.5). OBJECTIVE: Our goal was to develop a machine-learning model to predict mean PM2.5 and max PM2.5 concentrations in the Mexico City Metropolitan Area from 2004 through 2019. METHODS: We present a new modeling approach based on extreme gradient boosting (XGBoost) and inverse-distance weighting that uses AOD, meteorology, and land-use variables. We also investigated applications of our mean PM2.5 predictions that can aid local authorities in air-quality management and public-health surveillance, such as the co-occurrence of high PM2.5 and heat, compliance with local air-quality standards, and the relationship of PM2.5 exposure with social marginalization. RESULTS: Our models for mean and max PM2.5 exhibited good performance, with overall cross-validated mean absolute errors (MAE) of 3.68 and 9.20 µg/m3, respectively, compared to mean absolute deviations from the median (MAD) of 8.55 and 15.64 µg/m3. In 2010, everybody in the study region was exposed to unhealthy levels of PM2.5. Hotter days had greater PM2.5 concentrations. Finally, we found similar exposure to PM2.5 across levels of social marginalization. SIGNIFICANCE: Machine learning algorithms can be used to predict highly spatiotemporally resolved PM2.5 concentrations even in regions with sparse monitoring. IMPACT: Our PM2.5 predictions can aid local authorities in air-quality management and public-health surveillance, and they can advance epidemiological research in Central Mexico with state-of-the-art exposure assessment methods.

45,X/46,XY Mosaicism with Male Phenotype: Case Report.

Mixed gonadal dysgenesis is the most common chromosomal abnormality with ambiguous genitalia, defined as a 45,X/46,XY mosaicism. It can present with a normal male phenotype, ambiguous genitalia, or features of Turner syndrome. A 14-year-old patient was referred to the genetics clinic due to hypospadia, cryptorchidism, and aortic coarctation. During the physical examination, short stature, webbed neck, and Blashko lines on his back were noted. He had a previous karyotype reported as normal. However, due to an inadequate evolution and a low resolution on the previous test, a higher resolution karyotype was performed, identifying a mosaicism 45,X/46,XY. A multidisciplinary board examined the case, and follow-up with tumor markers was carried out to evaluate the presence of gonadoblastoma, one of the main complications in these patients. Treatment should be transdisciplinary and focused on the particular characteristics of each case. Other treatment alternatives include corrective surgery and hormonal therapy.

Urban airborne particle exposure impairs human lung and blood Mycobacterium tuberculosis immunity.

RATIONALE: Associations between urban (outdoor) airborne particulate matter (PM) exposure and TB and potential biological mechanisms are poorly explored. OBJECTIVES: To examine whether in vivo exposure to urban outdoor PM in Mexico City and in vitro exposure to urban outdoor PM2.5 (< 2.5 µm median aerodynamic diameter) alters human host immune cell responses to Mycobacterium tuberculosis. METHODS: Cellular toxicity (flow cytometry, proliferation assay (MTS assay)), M. tuberculosis and PM2.5 phagocytosis (microscopy), cytokine-producing cells (Enzyme-linked immune absorbent spot (ELISPOT)), and signalling pathway markers (western blot) were examined in bronchoalveolar cells (BAC) and peripheral blood mononuclear cells (PBMC) from healthy, non-smoking, residents of Mexico City (n=35; 13 female, 22 male). In vivo-acquired PM burden in alveolar macrophages (AM) was measured by digital image analysis. MEASUREMENTS AND MAIN RESULTS: In vitro exposure of AM to PM2.5 did not affect M. tuberculosis phagocytosis. High in vivo-acquired AM PM burden reduced constitutive, M. tuberculosis and PM-induced interleukin-1ß production in freshly isolated BAC but not in autologous PBMC while it reduced constitutive production of tumour necrosis factor-alpha in both BAC and PBMC. Further, PM burden was positively correlated with constitutive, PM, M. tuberculosis and purified protein derivative (PPD)-induced interferon gamma (IFN-γ) in BAC, and negatively correlated with PPD-induced IFN-γ in PBMC. CONCLUSIONS: Inhalation exposure to urban air pollution PM impairs important components of the protective human lung and systemic immune response against M. tuberculosis. PM load in AM is correlated with altered M. tuberculosis-induced cytokine production in the lung and systemic compartments. Chronic PM exposure with high constitutive expression of proinflammatory cytokines results in relative cellular unresponsiveness.

Uso de injertos libres -Snodgraft- en corrección de hipospadias complicadas en un sólo tiempo / Use of free grafts -Snodgraft- in complicated hypospadias repair in a single stage

Objetivos: La incisión y tubularización de la placa uretral "Snodgrass" es la técnica más utilizada en nuestro medio en la corrección de hipospadias, tiene limitantes cuando la placa uretral es pobre, estrecha o hay cicatriz de cirugías previas. Se han desarrollado técnicas nuevas como la ampliación de la placa uretral nativa con un injerto libre en el fondo de la misma y cierre primario de ésta; técnica denominada "Snodgraft" (Snodgrass + Graft/Injerto) ó Inlay. Para nuestro conocimiento en nuestro país existe poca o ninguna experiencia en el uso de injertos libres como parte integral en la corrección de hipospadias. Es este el primer trabajo realizado en Colombia. Material y Métodos: Se incluyeron todos los pacientes a quienes se les realizo corrección de hipospadias con técnica Snodgraft desde marzo 2006 hasta abril 2008 en la Clínica Infantil de Colsubsidio y Hospital Universitario San Ignacio en Bogotá Colombia. Divididos en dos grupos: A: Sin cirugía previa. B: Cirugía previa de hipospadias fallida. Se consideró éxito los que cumplieron los objetivos quirúrgicos de: Ausencia de fístulas, meato glanular, chorro anterógrado, buen resultado cosmético. Se hizo registro fotográfico pre y post quirúrgico. Análisis de Resultados: Se incluyeron 17 pacientes, edad promedio 4.2 años (rango:1.25 - 15). hipospadias del tercio medio: 75 por cien grupo A y 77por cien en el B. Se utilizo mucosa prepucial en el 100 por cien del grupo A. Mucosa oral en 78 por ciendel grupo B. Se utilizo colgajo pediculado de dartos sobre la línea de sutura de la neo uretra en todos los pacientes de ambos grupos excepto uno del B que se cubrió con túnica vaginal. 16 pacientes se derivaron con catéter uretral siliconado y uno con cistostomía. 6 complicaciones (35.3 por cien ), 2 Fístulas (11.7 por cien) que requirieron nueva cirugía, las 4 restantes: estrechez del meato (2), fístula proximal, necrosis parcial de piel, resolvieron sin intervención quirúrgica. Finalmente luego de la segunda...