Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, the effect of direct exposure of formaldehyde in different concentration was observed in 14 rabbits aged 3-6 months and weighing 1100-1200 g. The animals were divided into two groups with six animals in each group, and two animals were kept as control. The animals of group I were exposed to 10% formalin for 12 weeks and those of group II to 40% formalin solution for 6 weeks. After completion of the experimental periods, the animals were killed and the tissue samples were collected from the nasal cavity, trachea and lungs in 10% neutral buffered formalin and Karnovsky's fixative to examine the histological and electron microscopic changes in the organs. The mucosal cells of nasal cavity showed loss of cilia and epithelial metaplasia was observed in places. There was vascular congestion and mild subepithelial odema. The tracheal epithelium was organized with hyperchromatic nuclei. There was subepithelial odema along with lymphomononuclear cellular infiltration. There was marked emphysema evident as bulla formation of air spaces due to rupture of interalveolar septum. An increased cellularity of alveolar wall was observed, resulting in its thickening. The epithelial lining of bronchioles showed loss of mucosal folds and hyperplasia of cells along with peribronchial lymphomononuclear cellular infiltration. Thickening of wall of blood vessels was evident. Congestion and haemorrhages were observed in places. It is concluded that the histopathological changes were more remarkable in the animals exposed to 40% formaldehyde for short duration than the animals exposed to 10% formaldehyde for longer duration with a more severe effect on the upper part of the respiratory tract than the lower one.
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PMID:Toxic effect of formaldehyde on the respiratory organs of rabbits: a light and electron microscopic study. 2134 28

Lung cysteine cathepsin S (CatS) that is a potent elastase plays a deleterious role in alveolar remodeling during smoke-induced emphysema. Despite the presence of a reactive nucleophilic cysteine (Cys25) within its active site, most of its elastinolytic activity is preserved after exposure to cigarette smoke extract (CSE), a major source of sulfhydryl oxidants. This result led us to decipher CatS resistance to major and representative CSE oxidants: hydrogen peroxide, formaldehyde, acrolein and peroxynitrite. CatS was inactivated by hydrogen peroxide, peroxynitrite and acrolein in a time- and dose-dependent manner, while formaldehyde was a weaker oxidant. Hydrogen peroxide, but not CSE, formaldehyde, and peroxynitrite impaired the autocatalytic maturation of pro-CatS, whereas acrolein prevented the formation of mature CatS without hindering the initial step of the two-step autocatalytic process. Far-UV CD spectra analysis supported that oxidation by CSE and hydrogen peroxide did not led to a structural alteration of CatS, despite a notable increase of protein carbonylation, a major hallmark of oxidative damage. Evaluation of the oxidation status of Cys25 by specific biotinylated redox sensing probes suggested the formation of sulfenic acid followed by a slower conversion to sulfinic acid after incubation with hydrogen peroxide. Addition of reducing reagents (dithiothreitol, glutathione and N-acetyl cysteine) led to a partial recovery of CatS activity following incubation with CSE, hydrogen peroxide and peroxynitrite. Current results provide some mechanistic evidence of CatS stability and activity in the presence of CSE, supporting its harmful contribution to the pathophysiology of emphysema.
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PMID:Oxidation of cathepsin S by major chemicals of cigarette smoke. 3208 13


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