Document Detail

Changes in sedimentation of surfactant in ventilated excised rat lungs. Physical alterations in surfactant associated with the development and reversal of atelectasis.
MedLine Citation:
PMID:  379047     Owner:  NLM     Status:  MEDLINE    
We ventilated excised rat lungs at a constant tidal volume (CTV); they developed areas of atelectasis which could be reversed by a large inflation (CTV + I) or prevented by the addition of positive end-expiratory pressure to the CTV. To explore the possibility that these modes of ventilation led to changes in surfactant, we lavaged the lungs and centrifuged the returns at 500 g; we measured the amount of disaturated phosphatidylcholine (DSPC) in the resultant pellet and supernatant fluid as a marker for surfactant. We found 16.9+/-1.5 (mean+/-SE), 38.0+/-2.4, 18.3+/-1.6, and 21.7+/-2.3% of the total lavage DSPC, in the pellet from freshly excised, CTV, CTV + I, and positive end-expiratory pressure to the CTV lungs, respectively. The total amount of lavage DSPC was the same in all groups. The ultrastructure of acellular material pelleted by sequential centrifugation of lavage returns at 500, 1,000, and 60,000 g was examined. We found mostly tubular myelin in the 500-g and 1,000-g pellets, but no tubular myelin in the 60,000-g pellet. Air inflation pressure-volume measurements from the degassed state revealed that the opening pressure and recoil pressures up to 75% of total lung capacity were significantly higher in the CTV than in the CTV + I lungs. There were no differences between these groups in air deflation or in saline inflation and deflation pressure-volume measurements. Our findings suggest that CTV leads to increases in the tubular myelin form of surfactant and that this leads to increased surface tension in alveoli which results in alveolar collapse.
L A Thet; L Clerch; G D Massaro; D Massaro
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of clinical investigation     Volume:  64     ISSN:  0021-9738     ISO Abbreviation:  J. Clin. Invest.     Publication Date:  1979 Aug 
Date Detail:
Created Date:  1979-09-25     Completed Date:  1979-09-25     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7802877     Medline TA:  J Clin Invest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  600-8     Citation Subset:  AIM; IM    
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MeSH Terms
Centrifugation, Isopycnic
Lung / metabolism*,  ultrastructure
Lung Compliance
Lung Volume Measurements
Phosphatidylcholines / metabolism
Phospholipids / metabolism
Positive-Pressure Respiration
Pulmonary Atelectasis / metabolism*,  pathology,  physiopathology
Pulmonary Surfactants / metabolism*
Respiration, Artificial*
Tidal Volume
Reg. No./Substance:
0/Phosphatidylcholines; 0/Phospholipids; 0/Pulmonary Surfactants

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

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