American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Oct 2020
Aerosol Generation from the Respiratory Tract with Various Modes of Oxygen Delivery.
Rationale: Aerosol generation with modes of oxygen therapy such as high-flow nasal cannula and noninvasive positive-pressure ventilation is a concern for healthcare workers during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. The amount of aerosol generation from the respiratory tract with these various oxygen modalities is unknown. Objectives: To measure the size and number concentration of particles and droplets generated from the respiratory tract of humans exposed to various oxygen delivery modalities. ⋯ Measured aerosol concentration did not significantly increase with the use of either humidified high-flow nasal cannula or noninvasive positive-pressure ventilation. This was the case during normal breathing, talking, deep breathing, and coughing. Conclusions: Oxygen delivery modalities of humidified high-flow nasal cannula and noninvasive positive-pressure ventilation do not increase aerosol generation from the respiratory tract in healthy human participants with no active pulmonary disease measured in a negative-pressure room.
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Am. J. Respir. Crit. Care Med. · Oct 2020
Targeting p16INK4a Promotes Lipofibroblasts and Alveolar Regeneration After Early Life Injury.
Rationale: Promoting endogenous pulmonary regeneration is crucial after damage to restore normal lungs and prevent the onset of chronic adult lung diseases. Objectives: To investigate whether the cell-cycle inhibitor p16INK4a limits lung regeneration after newborn bronchopulmonary dysplasia (BPD), a condition characterized by the arrest of alveolar development, leading to adult sequelae. Methods: We exposed p16INK4a-/- and p16INK4aATTAC (apoptosis through targeted activation of caspase 8) transgenic mice to postnatal hyperoxia, followed by pneumonectomy of the p16INK4a-/- mice. ⋯ After pneumonectomy, p16INK4a deficiency again led to an increase in lipofibroblast and AT2 cell numbers in the contralateral lung. Finally, we observed p16INK4a mRNA overexpression in the blood and lungs of preterm newborns, which persisted in the blood of older survivors of BPD. Conclusions: These data demonstrate the potential of targeting p16INK4a and promoting lipofibroblast development to stimulate alveolar regeneration from childhood to adulthood.