Document Detail

Alterations in stress distributions around interalveolar pores after exposure to papain in dogs.
MedLine Citation:
PMID:  6894357     Owner:  NLM     Status:  MEDLINE    
Electron microscopic examination of dog lungs after exposure to papain for as little as 30 min showed removal of surfactant material from the pores of Kohn, and significant enlargement of the pores. We analyzed these early events in terms of structural mechanics, and concluded that: (1) The approximate doubling of the average diameter indicates a lowering of the effective modulus of elasticity in the vicinity of the pores to less than 50% of its original value, which is consistent with the destruction of elastin. (2) The removal of the surfactant material, which normally occludes the pores, results in the loss of the force caused by surface tension, which normally acts at the rim of the pore, and alleviates maximal tissue stress. This lost force can result in a stress increase on the elastin by as much as 20 to 30% of its strength. (3) The whole lung volume pressure deflation curves obtained in hamsters after exposure to papain show a significant increase in compliance associated with papain treatment. Degradation in the elastic modulus of the tissue, caused by the papain, contributes to such an increase. On the other hand, surface tension measurements from canine lung extracts after exposure to papain yield results that should contribute to a decrease in compliance. Because papain treatment destroys the continuity of the lining layer, this contribution is minimized, and the effect on the tissue dominates, resulting in a net increase in compliance.
R J Sanderson; L Gaddy; S Parra; T Takaro
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  123     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1981 Mar 
Date Detail:
Created Date:  1981-06-13     Completed Date:  1981-06-13     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  327-32     Citation Subset:  AIM; IM    
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MeSH Terms
Lung / metabolism,  ultrastructure*
Lung Compliance
Lung Volume Measurements
Papain / pharmacology*
Pulmonary Alveoli / ultrastructure*
Pulmonary Surfactants / metabolism*
Surface Tension
Time Factors
Reg. No./Substance:
0/Pulmonary Surfactants; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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