Evaluating silicosis risk: Assessing dust constitution and influence of water as a primary prevention measure in cutting and polishing of silica agglomerates, granite and marble.

An increasing number of silicosis cases have been reported related to the use of silica agglomerates. Many studies agree on the severity of this disease, which often presents with severe clinical forms in young workers and after a short latency period. Are there differences in the composition of dust generated by cutting and polishing with silica agglomerates versus granite and marble? Does the use of water injection reduce the risk associated with the use of these materials? We carried out a comparative observational-analytical study, measuring the concentration of dust generated during different machining operations on three different materials: granite, marble, and silica agglomerates. The effect of water injection on dust generation was evaluated. Personal sampling pumps were used, connected to a cyclone with polyvinyl chloride filters. The flow rate of the pumps was adjusted using a piston flowmeter. Measurements with a cascade impactor were made to assess the size distribution of respirable crystalline silica particles within the respirable fraction. In addition, environmental measurements with a spectrometer were made. 10 tests were carried out on granite and silica agglomerates for each procedure. In the case of marble, with very low silica content, only 2 tests of each type were carried out. Duration of each measurement was between 6 and 25 min. Cleaning times were set for each of the operations. The amount of dust collected in the respirable fraction was 70.85, 32.50 and 35.78 mg/m3 for dry cutting; 6.50, 3.75 and 3.95 mg/m3 for wet cutting; and 21.35, 13.68 and 17.50 mg/m3 for dry polishing, for granite, marble, and silica agglomerates respectively. Dry procedures in marble, silica agglomerates and granite showed higher dust concentration of particles smaller than 0.5 µm. Silica agglomerates showed higher concentrations of respirable crystalline silica particles than granite and marble, mainly with dry procedures. The greater production of small particles in dry and wet procedures with silica agglomerates shows that water injection is an insufficient preventive measure.

In silico prototype of a human lung with a single airway to predict particle deposition.

BACKGROUND: Experimental analyses of the flow of drug particles inside the human lung usually require that the patient be exposed to radiation and also of expensive equipment that often lack of enough accuracy. Numerical calculations based on CFD (computational fluid dynamics) have been proven to be a valuable tool to analyze flows in diverse applications. METHODS: The complexity of the human lung disallows running calculations on complete lung models due to the large number of cells that would be required. In this work, using a proprietary methodology, particle deposition in the lung is simulated by reducing its multiple branches to a single path. RESULTS: The tested flow rates were 18, 30, and 75 L min-1 , which are equivalent to different respiratory rates varying from light activity to heavy exercise. Most of the particles are accumulated in the upper airways, mainly at the mouth and also at the confluence of the larynx and the trachea (epiglottis), while the remaining particles travel across the lung. The reported procedure allowed simulating the operation of the entire lung by means of a single individual path. CONCLUSIONS: The obtained calculations are in good agreement with the experimental results found in the technical literature, thus showing that the model can provide a realistic description of the lung operation, while avoiding high computational costs. Moreover, the calculations suggest that particle sizes above 15 µm and inspiratory flows higher than 30 L min-1 must be avoided in order to allow drug particles to reach the lower airways.

Utilidad de la resonancia magnética en la sospecha de cáncer de pulmón en pacientes con silicosis / Usefulness of Magnetic Resonance in Suspected Lung Cancer in Silicosis Patients

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Más Platón y menos Prozac(R): llega el ASMA-ZUMAB / More Platon And Less Prozac(R): The Arrival Of ASTHMA-ZUMAB

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Mediastinal liposarcoma in a 30-year-old woman with dyspnea and chest pain.

Mediastinal liposarcoma (ML) is a rare mesenchymal tumor, accounting for less than 1% of mediastinal tumors. They have a slow growth, so they may not give symptoms for a long time, until the tumor produces compression of close structures. The treatment of choice is surgery, which can be combined with chemo-radiotherapy. We present a case in which the diagnosis of a ML was made in a 30-year-old woman with dyspnea and chest pain.

Aplicaciones de la dinámica de fluidos computacional a la neumología / Use of Computational Fluid Dynamics in Respiratory Medicine

La dinámica de fluidos computacional (CFD) se define como la técnica informática que busca la simulación del movimiento de los fluidos. Las principales ventajas de la técnica de CFD sobre otro tipo de estudios de mecánica de fluidos son la reducción sustancial de tiempo y costes en los experimentos, la posibilidad de analizar sistemas o condiciones muy difíciles de simular experimentalmente, como es el caso de las vías aéreas, y un nivel de detalle prácticamente ilimitado. Utilizamos el programa de CFD Ansys-Fluent para elaborar un modelo de la vía aérea de conducción que permite la simulación de distintos caudales de flujo inspiratorio, así como del depósito de partículas inhaladas de diferentes diámetros, obteniendo resultados concordantes con la literatura existente utilizando otros procedimientos. De este modo se pretende abrir una nueva vía a la individualización de los tratamientos para las distintas patologías respiratorias

Computational Fluid Dynamics (CFD) is a computer-based tool for simulating fluid movement. The main advantages of CFD over other fluid mechanics studies include: substantial savings in time and cost, the analysis of systems or conditions that are very difficult to simulate experimentally (as is the case of the airways), and a practically unlimited level of detail. We used the Ansys-Fluent CFD program to develop a conducting airway model to simulate different inspiratory flow rates and the deposition of inhaled particles of varying diameters, obtaining results consistent with those reported in the literature using other procedures. We hope this approach will enable clinicians to further individualize the treatment of different respiratory diseases

Use of computational fluid dynamics in respiratory medicine.

Computational Fluid Dynamics (CFD) is a computer-based tool for simulating fluid movement. The main advantages of CFD over other fluid mechanics studies include: substantial savings in time and cost, the analysis of systems or conditions that are very difficult to simulate experimentally (as is the case of the airways), and a practically unlimited level of detail. We used the Ansys-Fluent CFD program to develop a conducting airway model to simulate different inspiratory flow rates and the deposition of inhaled particles of varying diameters, obtaining results consistent with those reported in the literature using other procedures. We hope this approach will enable clinicians to further individualize the treatment of different respiratory diseases.

Depósito pulmonar de partículas inhaladas / Deposition of Inhaled Particles in the Lungs

La medicación inhalada constituye el tratamiento de primera línea de enfermedades como el asma o la enfermedad pulmonar obstructiva crónica. Su efectividad está en relación con la cantidad de fármaco que logre depositarse más allá de la región orofaríngea, con el lugar en que se produzca el depósito y con la distribución uniforme o no del mismo. Otros factores trascendentes son el tamaño de las partículas inhaladas, las condiciones de respiración, la geometría de las vías aéreas y los mecanismos de aclaramiento mucociliar. Actualmente se están aplicando modelos matemáticos que permiten describir el depósito de fármacos inhalados a partir del tamaño de las moléculas, el flujo inspiratorio y la distribución anatómica del árbol bronquial. El depósito de partículas en las vías aéreas pequeñas recibe la máxima atención de las empresas farmacéuticas y es del máximo interés para poder controlar mejor a los pacientes que reciben estos fármacos(AU)

Inhaled medication is the first-line treatment of diseases such as asthma or chronic obstructive pulmonary disease. Its effectiveness is related to the amount of drug deposited beyond the oropharyngeal region, the place where the deposit occurs and its distribution (uniform or not). It is also important to consider the size of the inhaled particles, the breathing conditions, the geometry of the airways and the mucociliary clearance mechanisms. Currently, mathematical models are being applied to describe the deposition of inhaled drugs based on the size of the particles, the inspiratory flow and the anatomical distribution of the bronchial tree. The deposition of particles in the small airways gets maximum attention from pharmaceutical companies and is of great interest as it is related with a better control in patients receiving these drugs(AU)

Deposition of inhaled particles in the lungs.

Inhaled medication is the first-line treatment of diseases such as asthma or chronic obstructive pulmonary disease. Its effectiveness is related to the amount of drug deposited beyond the oropharyngeal region, the place where the deposit occurs and its distribution (uniform or not). It is also important to consider the size of the inhaled particles, the breathing conditions, the geometry of the airways and the mucociliary clearance mechanisms. Currently, mathematical models are being applied to describe the deposition of inhaled drugs based on the size of the particles, the inspiratory flow and the anatomical distribution of the bronchial tree. The deposition of particles in the small airways gets maximum attention from pharmaceutical companies and is of great interest as it is related with a better control in patients receiving these drugs.