scholarly journals Numerical Modelling and Analysis of Peripheral Airway Asymmetry and Ventilation in the Human Adult Lung

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
F. S. Henry ◽  
C. J. Llapur ◽  
A. Tsuda ◽  
R. S. Tepper
Keyword(s):  
Phase Iii ◽  
Adult Lung ◽  
Human Adult ◽  
Airway Trees ◽  
Structural Abnormalities ◽  
Peripheral Airway ◽  
Experimental Trend ◽  
Human Adult Lung ◽  
Conducting Airways ◽  
Phase Iii Slope

We present a new one-dimensional model of gas transport in the human adult lung. The model comprises asymmetrically branching airways, and heterogeneous interregional ventilation. Our model differs from previous models in that we consider the asymmetry in both the conducting and the acinar airways in detail. Another novelty of our model is that we use simple analytical relationships to produce physiologically realistic models of the conducting and acinar airway trees. With this new model, we investigate the effects of airway asymmetry and heterogeneous interregional ventilation on the phase III slope in multibreath washouts. The model predicts the experimental trend of the increase in the phase III slope with breath number in multibreath washout studies for nitrogen, SF6 and helium. We confirm that asymmetrical branching in the acinus controls the magnitude of the first-breath phase III slope and find that heterogeneous interregional ventilation controls the way in which the slope changes with subsequent breaths. Asymmetry in the conducting airways appears to have little effect on the phase III slope. That the increase in slope appears to be largely controlled by interregional ventilation inhomogeneities should be of interest to those wishing to use multibreath washouts to detect the location of the structural abnormalities within the lung.

Human SP-A1 and SP-A2 genes are differentially regulated during development and by cAMP and glucocorticoids

1994 ◽  
Vol 266 (4) ◽  
pp. L367-L374 ◽  
Author(s):  
S. M. McCormick ◽  
C. R. Mendelson
Keyword(s):  
Lung Tissue ◽  
Protein A ◽  
Fetal Lung ◽  
Companion Paper ◽  
Primer Extension ◽  
Northern Analysis ◽  
Adult Lung ◽  
Human Adult ◽  
Mrna Transcripts ◽  
Human Adult Lung

Expression of the surfactant protein A (SP-A) gene is lung specific, developmentally induced, and regulated by adenosine 3',5'-cyclic monophosphate (cAMP) and glucocorticoids. Humans have two highly similar genes encoding SP-A (SP-A1 and SP-A2). In the companion paper [S.M. McCormick, V. Boggaram, and C.R. Mendelson Am. J. Physiol. 266 (Lung Cell. Mol. Physiol. 10): L354-L366, 1994] we report that SP-A1 and SP-A2 RNA transcripts are alternatively spliced at their 5' ends, resulting in nine different primer-extended transcripts. In the present study, primer extension was used to assess the relative levels of expression of the SP-A1 and SP-A2 genes in human adult lung tissue and in fetal lung tissues maintained in organ culture in the absence or presence of dibutyryl (DB)cAMP (1 mM) and dexamethasone (Dex, 10(-4) M). Primer extension and Northern analysis were used to assess the effects of these agents on the levels of expression of these genes. In human adult lung tissue, 65% of the SP-A mRNA transcripts were derived from the SP-A2 gene, whereas only 35% were from SP-A1. On the other hand, in lung tissue from a 28-wk gestation neonate, only SP-A1 mRNA transcripts were detected, and, in midgestation fetal lung cultured in control medium, 65% of the SP-A mRNA was found to be SP-A1 and 35% was SP-A2.(ABSTRACT TRUNCATED AT 250 WORDS)

Heterogeneous Proliferative Characteristics of Human Adult Lung Fibroblast Lines and Clonally Derived Fibroblasts from Control and Fibrotic Tissue

1988 ◽  
Vol 137 (3) ◽  
pp. 579-584 ◽  
Author(s):  
Manel Jordana ◽  
Jerry Schulman ◽  
Charlie McSharry ◽  
Louis B. Irving ◽  
Michael T. Newhouse ◽  
...  
Keyword(s):  
Lung Fibroblast ◽  
Adult Lung ◽  
Human Adult ◽  
Fibrotic Tissue ◽  
Human Adult Lung

scholarly journals Effect of histamine on proliferation of normal human adult lung fibroblasts.

Thorax ◽  
1988 ◽  
Vol 43 (7) ◽  
pp. 552-558 ◽  
Author(s):  
M Jordana ◽  
A D Befus ◽  
M T Newhouse ◽  
J Bienenstock ◽  
J Gauldie
Keyword(s):  
Lung Fibroblasts ◽  
Adult Lung ◽  
Human Adult ◽  
Normal Human ◽  
Human Adult Lung

scholarly journals Evidence for tissue-resident mesenchymal stem cells in human adult lung from studies of transplanted allografts

2007 ◽  
Vol 117 (4) ◽  
pp. 989-996 ◽  
Author(s):  
Vibha N. Lama ◽  
Lisa Smith ◽  
Linda Badri ◽  
Andrew Flint ◽  
Adin-Cristian Andrei ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Adult Lung ◽  
Human Adult ◽  
Human Adult Lung

Fast vs. slow exhalation before O2 inhalation alters subsequent phase III slope

1984 ◽  
Vol 56 (1) ◽  
pp. 52-56 ◽  
Author(s):  
T. S. Hurst ◽  
B. L. Graham ◽  
D. J. Cotton
Keyword(s):  
Total Lung Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Breath Holding ◽  
Small Airways ◽  
Residual Volume ◽  
Lung Capacity ◽  
Single Breath ◽  
Subsequent Phase ◽  
Phase Iii Slope

We studied 10 symptom-free lifetime non-smokers and 17 smokers all with normal pulmonary function studies. All subjects performed single-breath N2 washout tests by either exhaling slowly (“slow maneuver”) from end inspiration (EI) to residual volume (RV) or exhaling maximally (“fast maneuver”) from EI to RV. After either maneuver, subjects then slowly inhaled 100% O2 to total lung capacity (TLC) and without breath holding, exhaled slowly back to RV. In the nonsmokers seated upright phase III slope of single-breath N2 test (delta N2/l) was lower (P less than 0.01) for the fast vs. the slow maneuver, but this difference disappeared when the subjects repeated the maneuvers in the supine position. In contrast, delta N2/l was higher for the fast vs. the slow maneuver (P less than 0.01) in smokers seated upright. For the slow maneuver, delta N2/l was similar between smokers and nonsmokers but for the fast maneuvers delta N2/l was higher in smokers than nonsmokers (P less than 0.01). We suggest that the fast exhalation to RV decreases delta N2/l in normal subjects by decreasing apex-to-base differences in regional ratio of RV to TLC (RV/TLC) but increases delta N2/l in smokers, because regional RV/TLC increases distal to sites of small airways obstruction when the expiratory flow rate is increased.

Mode shift of an inhaled aerosol bolus is correlated with flow sequencing in the human lung

2002 ◽  
Vol 92 (3) ◽  
pp. 1232-1238 ◽  
Author(s):  
Christopher N. Mills ◽  
Chantal Darquenne ◽  
G. Kim Prisk
Keyword(s):  
Vital Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Mode Shift ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Posture Change ◽  
Supine Posture ◽  
Residual Capacity ◽  
Phase Iii Slope

We studied the effects on aerosol bolus inhalations of small changes in convective inhomogeneity induced by posture change from upright to supine in nine normal subjects. Vital capacity single-breath nitrogen washout tests were used to determine ventilatory inhomogeneity change between postures. Relative to upright, supine phase III slope was increased 33 ± 11% (mean ± SE, P < 0.05) and phase IV height increased 25 ± 11% ( P < 0.05), consistent with an increase in convective inhomogeneity likely due to increases in flow sequencing. Subjects also performed 0.5-μm-particle bolus inhalations to penetration volumes (Vp) between 150 and 1,200 ml during a standardized inhalation from residual volume to 1 liter above upright functional residual capacity. Mode shift (MS) in supine posture was more mouthward than upright at all Vp, changing by 11.6 ml at Vp = 150 ml ( P < 0.05) and 38.4 ml at Vp = 1,200 ml ( P < 0.05). MS and phase III slope changes correlated positively at deeper Vp. Deposition did not change at any Vp, suggesting that deposition did not cause the MS change. We propose that the MS change results from increased sequencing in supine vs. upright posture.

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