@entity7459 ( @entity6836 ) when inhaled in different concentrations and for varying times produces @entity651 which are dependent on the anatomic site in the lung and the duration of exposure. Single exposures to high concentrations of @entity6836 for 5-6 hr produce an intense cellular proliferation which regresses within 48 hr in all lung regions except the terminal respiratory bronchiole region and the alveoli where the proliferation persists for 4-7 days. This same delayed response is also observed in more chronic exposures. Histologically, the lesion in the terminal and respiratory bronchioles may resemble an obliterative @entity5924 , but the lesion clears if further exposure is terminated. Prolonged exposure to 2 ppm @entity6836 , 20-22 hr per day for 7 days per wk, produces an increase in total pulmonary upstream resistance in animals killed immediately after exposure; this resistence returns to normal values within 3 mo after removal from exposure. The internal surface area (ISA) is decreased after 12 mo exposure to @entity6836 , but this loss of surface progresses during the recovery period in air, suggesting an autonomous progression of the tissue destructive process. Exposure to 3.64 ppm @entity6836 with and without @entity238 ash for periods of 12-14 mo causes no increase in pulmonary resistance and no alteration in lung surface. Lung phospholipids and protein synthesis appear to be @entity308 following exposure to @entity6836 . Lecithin is significantly increased. The synthesis of proteases by alveolar macrophages is increased during @entity6836 exposure. @entity2118 present in animals exposed to @entity6836 simulate those found in @entity1 lungs of young cigarette smokers in the terminal and respiratory bronchioles. The mechanism of tissue injury by oxidants such as @entity6836 may involve free radical formation, and peroxidation of lipids or proteins.

Some effects of XXXX on the lung.

@entity1 :: ('9606', 'Species') :: ['human'] @entity7459 :: ('MESH:D009585', 'Chemical') :: ['Nitrogen dioxide'] @entity308 :: ('MESH:D003866', 'Disease') :: ['depressed'] @entity651 :: ('MESH:D055370', 'Disease') :: ['pulmonary injuries'] @entity5924 :: ('MESH:D001988', 'Disease') :: ['bronchiolitis'] @entity6836 :: ('CHEBI:29785', 'Chemical') :: ['NO2'] @entity2118 :: ('MESH:D010859', 'Disease') :: ['Pigmented alveolar macrophages'] @entity238 :: ('7227', 'Species') :: ['fly']
@entity7459 :: (MESH:D009585,Chemical) :: ['nitrogen dioxide']
