Brazil is a country of continental dimensions with a large heterogeneity of climates
and massive mixing of the population. Almost the entire national territory is located
between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the
south certainly makes Brazil one of the countries of the world with greater extent of
land in proximity to the sun. The Brazilian coastline, where most of its population
lives, is more than 8,500 km long. Due to geographic characteristics and cultural
trends, Brazilians are among the peoples with the highest annual exposure to the sun.
Epidemiological data show a continuing increase in the incidence of non-melanoma and
melanoma skin cancers. Photoprotection can be understood as a set of measures aimed
at reducing sun exposure and at preventing the development of acute and chronic
actinic damage. Due to the peculiarities of Brazilian territory and culture, it would
not be advisable to replicate the concepts of photoprotection from other developed
countries, places with completely different climates and populations. Thus the
Brazilian Society of Dermatology has developed the Brazilian Consensus on
Photoprotection, the first official document on photoprotection developed in Brazil
for Brazilians, with recommendations on matters involving photoprotection.
This study was undertaken to test whether the structural remodelling of pulmonary parenchyma can be sequentially altered in a model and method that demonstrate the progression of the disease and result in remodelling within the lungs that is typical of idiopathic pulmonary fibrosis. Three groups of mice were studied: (i) animals that received 3-5-di-tert-butyl-4-hydroxytoluene (BHT) and were killed after 2 weeks (early BHT = 9); (ii) animals that received BHT and were killed after 4 weeks (late BHT = 11); (iii) animals that received corn oil solution (control = 10). The mice were placed in a ventilated Plexiglas chamber with a mixture of pure humidified oxygen and compressed air. Lung histological sections underwent haematoxylin-eosin, immunohistochemistry (epithelial, endothelial and immune cells) and specific staining (collagen/elastic fibres) methods for morphometric analysis. When compared with the control group, early BHT and late BHT groups showed significant decrease of type II pneumocytes, lower vascular density in both and higher endothelial activity. CD4 was increased in late BHT compared with early and control groups, while CD8, macrophage and neutrophil cells were more prominent only in early BHT. The collagenous fibre density were significantly higher only in late BHT, whereas elastic fibre content in late BHT was lower than that in control group. We conclude that the BHT experimental model is pathologically very similar to human usual interstitial pneumonia. This feature is important in the identification of animal models of idiopathic pulmonary fibrosis that can accurately reflect the pathogenesis and progression of the human disease.
SummaryBackground: Prosthetic valve leak is a possible complication of surgical valve replacement. Although uncommon, its consequences may be serious. Few studies correlate the degree of prosthetic valve leak with clinical events.
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