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Short-term reversibility of ultrastructural changes in pulmonary capillaries caused by stress failureWe previously showed that when the pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to determine whether some of the ultrastructural changes are rapidly reversible when the capillary pressure is reduced. To test this, the Ptm was raised to 52.5 cmH2O for 1 min of blood perfusion and then reduced to 12.5 cmH2O for 3 min of saline-dextran perfusion, followed by intravascular fixation at the same pressure. In another group of animals, the pressure was elevated for 1 min of blood and 3 min of saline-dextran before being reduced. The results were compared with previous studies in which the capillary pressures were maintained elevated at 52.5 cmH2O during the entire procedure. Control studies were also done at sustained low pressures. The results showed that the number of endothelial and epithelial breaks per millimeter and the total fraction area of the breaks were reduced when the pressure was lowered. For example, the number of endothelial breaks per millimeter decreased from 7.1 +/- 2.1 to 2.4 +/- 0.7, and the number of epithelial breaks per millimeter fell from 11.4 +/- 3.7 to 3.4 +/- 0.7. There was evidence that the breaks that closed were those that were initially small and were associated with an intact basement membrane. The results suggest that cells can move along their underlying matrix by rapid disengagement and reattachment of cell adhesion molecules, causing breaks to open or close within minutes.(ABSTRACT TRUNCATED AT 250 WORDS).
Document ID
20050000615
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Elliott, A. R.
(University of California San Diego, La Jolla 92093-0623)
Fu, Z.
Tsukimoto, K.
Prediletto, R.
Mathieu-Costello, O.
West, J. B.
Date Acquired
August 22, 2013
Publication Date
September 1, 1992
Publication Information
Publication: Journal of applied physiology (Bethesda, Md. : 1985)
Volume: 73
Issue: 3
ISSN: 8750-7587
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: HL-17331-16
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Cardiopulmonary

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