Browsing by Subject "Hyperoxia"

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    Oxygen toxicity in the infant rhesus monkey lung. Light microscopic and ultrastructural studies
    (Murcia : F. Hernández, 1986) Ainsworthl, Dorothy M.; Keithl, lngegerd; Lobas, Jeffrey G.; Farrel, Philip M.; Eicker, W.
    Eight monkeys were anesthetized with ketamine hydrochloride and positive pressure ventilated with >95% oxygen (tests) or room air (controls) for 24 hours. Two test monkeys and one control were treated with E. col; endotoxin (500 pg/kg) 1V at the start of the study and after 12 hours. Histopathological changes in the lung parenchyma were evaluated using light and electron microscopy. Interstitial edema was detected as early as 24 hours after the onset of hyperoxia but there was no significant increase in the alveolar-capillary distance (blood-air barrier). Morphologic signs of oxygen toxicity further included swelling and disruption of vascular endothelium, and swelling of alveolar Type I1 pneumocytes. There was no difference in the number of macrophages per high power field between the four groups but significant differences were observed in the number of neuroepithelial bodies (NEBs) per cmL and mast cells per high power field at the light microscopic level. Treatment with endotoxin did not protect against oxygen toxicity and was associated with an exacerbation of the morphological alterations in the lung parenchyma and swelling of alveolar Type 1 pneumocytes.
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    Pulmonary expression of vascular endothelial growth factor (VEGF) and alveolar septation in a newborn rat model exposed to acute hypoxia and recovered under conditions of air or hyperoxia
    (Murcia : F. Hernández, 2009) Remesal, Ana; Pedraz, Carmen; San Feliciano, Laura; Ludeña, Dolores
    Vascular endothelial growth factor (VEGF) is an endothelial cell growth factor expressed in normal lung tissue. The aim of the study was to investigate the expression of VEGF and its repercussions as regards alveolarization in the developing rat lung. We studied pulmonary VEGF expression at 0 and 14 days of life in Wistar rats. Rat pups were exposed to hypoxia for two hours during the first hours of life and recovered under conditions of hyperoxia or normoxia for a further two hours, or not recovered. The animals of the control group were only exposed to conditions of normoxia. Our results showed that VEGF was increased in the lungs of the animals that were exposed to hypoxia but we did not find any correlation with the septation. The VEGF was decreased in the lungs of animals exposed to hyperoxia after neonatal hypoxia. We observed this at 0 and 14 days of life, and it was correlated with a lower degree of alveolarization at 14 days of life. Our data suggest that hyperoxia after neonatal hypoxia at birth may give rise to a decrease in the expression of VEGF, possibly permanently, together with a reduction in alveolar development.
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    Ultrastructure of the rat hippocampus after isobaric respirative hyperoxia
    (Murcia : F. Hernández, 1991) Manthos, A.; Tsolaki, M.; Kaidoglou, K.; Alvanou, A.; Hatjinikolaou, K.; Hatjiagorakis, A.; Giala, M.; Foroglou, Ch.
    After exposing rats to an environment of isobaric h,v ~eroxia.th e ~iltrastructurala lterations of the L hippocampus were studied. No major alterations were found in the nerve cells. Of importante was the moderate osmiophilia and the spindle-like transformation of the mitochondria. Vacuolated synapses and neuraxons were found, containing amorphous material. Astrocytic perivascular end feet were found vacuolated in many places. Many endothelial cells of the capillaries presented high osmiophilia, which sonletimes prevented structural details. Quantitatively, the findings were proportionally related to the time of exposure in the pure oxygen atmosphere (24,48 and 65 hours)