Ultrastructural alterations during embryonic rats' lung development caused by ozone.

Ozone (O3) is an oxidizing agent that acts on phospholipids, proteins and sugars of cellular membranes producing free radicals, which cause oxidative damages. The O3 exposure has been used as a model to study oxidative stress, in which the respiratory airways represent the entrance to the organism. In this study, ultrastructural alterations were identified at the bronchiolar level during the intra-uterine lung development, using an O3 exposure model in pregnant rats during 18, 20 and 21 days of gestation. Twelve pregnant Wistar rats, six controls and six exposed to 1 ppm O3 inhalation during 12 h per day, were used. The rats were sacrificed at gestational days 18, 20 and 21; the fetuses were obtained and their lungs dissected. The ultrastructural analysis evidenced swollen mitochondria, cytoplasmic vacuolization of the epithelial cells and structural disorder caused by the oxidative stress. At gestation day 20, flake-off epithelial cells and laminar bodies in the bronchiolar lumen were observed. In the 21-gestation-day group, the mitochondria were edematous and their cristae were disrupted by the damage caused in mitochondrial membranes.

Taenia solium cysticercosis: lymphocytes in the inflammatory reaction in naturally infected pigs.

Immunohistochemistry was used to examine the type of lymphocytes in muscle taeniosis-cysticercosis in naturally infected pigs. The inflammatory response studied was classified into lesions of grades 1, 3, and 5. In grade 1, with a minimal inflammatory infiltrate consisting of eosinophils and a few mononuclear cells, the immunostaining showed more CD4+ cells than CD8+ cells and IgM cells. In grade 3, when the granulomatous reaction was not yet well developed and the destruction of the parasite began, CD4+ and Ig M+ were the predominant cells, although CD8+ cells showed a notable increase. In grade 5, with a few parasitic structures surrounded by an extensive granulomatous infiltrate, lymphocyte subsets were decreased in number and did not show differences from grade 1 except for IgM+ cells, which remained increased. The organization of an active inflammatory response against the metacestode of Taenia solium in pigs includes the sequential participation of CD4+, CD8+ and IgM+ lymphocytes.