scholarly journals Microscopic modeling of NO and S-nitrosoglutathione kinetics and transport in human airways

2001 ◽  
Vol 90 (3) ◽  
pp. 777-788 ◽  
Author(s):  
Hye-Won Shin ◽  
Steven C. George
Keyword(s):  
Steady State ◽  
Epithelial Cells ◽  
Inflammatory Diseases ◽  
Small Airways ◽  
Exhaled Breath ◽  
Exhaled No ◽  
Large Airways ◽  
Human Airways ◽  
Microscopic Modeling ◽  
Using Data

Nitric oxide (NO) appears in the exhaled breath and is elevated in inflammatory diseases. We developed a steady-state mathematical model of the bronchial mucosa for normal small and large airways to understand NO and S-nitrosoglutathione (GSNO) kinetics and transport using data from the existing literature. Our model predicts that mean steady-state NO and GSNO concentrations for large airways ( generation 1) are 2.68 nM and 113 pM, respectively, in the epithelial cells and 0.11 nM (∼66 ppb) and 507 nM in the mucus. For small airways ( generation 15), the mean concentrations of NO and GSNO, respectively, are 0.26 nM and 21 pM in the epithelial cells and 0.02 nM (∼12 ppb) and 132 nM in the mucus. The concentrations in the mucus compare favorably to experimentally measured values. We conclude that 1) the majority of free NO in the mucus, and thus exhaled NO, is due to diffusion of free NO from the epithelial cell and 2) the heterogeneous airway contribution to exhaled NO is due to heterogeneous airway geometries, such as epithelium and mucus thickness.

scholarly journals Topography-dependent gene expression and function of common cell archetypes in large and small porcine airways

2021 ◽  
Author(s):  
Alejandro A. Pezzulo ◽  
Andrew L. Thurman ◽  
Xiaopeng Li ◽  
Raul Villacreses ◽  
Wenjie Yu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Airway Epithelial Cells ◽  
Small Airway ◽  
Small Airways ◽  
Sequencing Data ◽  
Airway Epithelia ◽  
Large Airways ◽  
And Function ◽  
Airway Cells

SummaryThe small airways of humans are affected early in several lung diseases. However, because they are relatively inaccessible, little is known about the epithelial cells that line these airways. We performed a single cell RNA-seq census of small and large airways of wild-type pigs and pigs with disrupted cystic fibrosis transmembrane conductance regulator (CFTR) gene. The sequencing data showed that small airway epithelia had similar major cell types as large airways but no ionocytes; moreover, lack ofCFTRexpression had minimal effect on the transcriptome. Small airway epithelial cells expressed a different transcriptome than large airway cells. Quantitative immunohistochemistry showed that small airway basal cells participate in epithelial barrier function. Finally, sequencing data and in vitro electrophysiologic studies suggest that small airway epithelia have a water and ion transport advantage. Our data highlight the archetypal nature of basal, secretory, and ciliated airway cells with location-dependent gene expression and function.

Airway surface liquid thickness as a function of lung volume in small airways of the guinea pig

1994 ◽  
Vol 77 (5) ◽  
pp. 2333-2340 ◽  
Author(s):  
D. Yager ◽  
T. Cloutier ◽  
H. Feldman ◽  
J. Bastacky ◽  
J. M. Drazen ◽  
...  
Keyword(s):  
Surface Tension ◽  
Epithelial Cells ◽  
Guinea Pig ◽  
Cross Sections ◽  
Lung Volume ◽  
Longitudinal Direction ◽  
Small Airways ◽  
Airway Surface Liquid ◽  
Residual Capacity ◽  
Surface Liquid

The average thickness and distribution of airway surface liquid (ASL) on the luminal surface of peripheral airways were measured in normal guinea pig lungs frozen at functional residual capacity (FRC) and total lung capacity (TLC). Tissue blocks containing cross sections of airways of internal perimeter 0.188–3.342 mm were cut from frozen lungs and imaged by low-temperature scanning electron microscopy (LTSEM). Measurements made from LTSEM images were found to be independent of freezing rate by comparison of measurements at rapid and slow freezing rates. At both lung volumes, the ASL was not uniformly distributed in either the circumferential or longitudinal direction; there were regions of ASL where its thickness was < 0.1 micron, whereas in other regions ASL collected in pools. Discernible liquid on the surfaces of airways frozen at FRC followed the contours of epithelial cells and collected in pockets formed by neighboring cells, a geometry consistent with a low value of surface tension at the air-liquid interface. At TLC airway liquid collected to cover epithelial cells and to form a liquid meniscus, a geometry consistent with a higher value of surface tension. The average ASL thickness (h) was approximately proportional to the square root of airway internal perimeter, regardless of lung volume. For airways of internal perimeter 250 and 1,800 microns, h was 0.9 and 1.8 microns at FRC and 1.7 and 3.7 microns at TLC, respectively. For a given airway internal perimeter, h was 1.99 times thicker at TLC than at FRC; the difference was statistically significant (P < 0.01; 95% confidence interval 1.29–3.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Clara Cell Protein–positive Epithelial Cells Are Reduced in Small Airways of Asthmatics

1999 ◽  
Vol 160 (3) ◽  
pp. 930-933 ◽  
Author(s):  
NORIHARU SHIJUBO ◽  
YOSHIHISA ITOH ◽  
TETSUJI YAMAGUCHI ◽  
AKIHIRO IMADA ◽  
MICHIO HIRASAWA ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Clara Cell ◽  
Cell Protein ◽  
Small Airways ◽  
Clara Cell Protein

Energetics of sugar transport by isolated intestinal epithelial cells: effects of cytochalasin B

1979 ◽  
Vol 237 (1) ◽  
pp. C56-C63 ◽  
Author(s):  
G. A. Kimmich ◽  
J. Randles
Keyword(s):  
Steady State ◽  
Epithelial Cells ◽  
Transport System ◽  
Cytochalasin B ◽  
Intestinal Epithelial Cells ◽  
Sugar Accumulation ◽  
Facilitated Diffusion ◽  
Intestinal Epithelial ◽  
Passive System ◽  
Concentration Gradients

The capability of isolated intestinal epithelial cells to establish concentration gradients of 3-O-methylglucose (3-OMG) by a Na+-dependent transport system is limited by concomitant function of a Na+-independent, facilitated diffusion transport system. Monosaccharides accumulated by the active system are continuously lost via the passive system, which acts to lower steady-state sugar gradients maintained by the cell. Cytochalasin B is a potent inhibitor of the passive system and allows the cells to establish a sugar gradient that is much higher than normal. When extracellular [3-;OMG] is 1 mM, cytochalasin induces sugar accumulation ratios of 30-;fold (+/- phlorizin) in contrast to control ratios of approximately 10-;fold. When [3-;OMG] is 0.1 mM, cytochalasin (0.1 mM) induces 40-;fold accumulation ratios. When changes in extracellular sugar concentration are considered, steady-state concentration gradients observed are 70-;fold. For a Na:sugar coupling stoichiometry of 1:1, gradients of this magnitude represent the approximate theoretical maximum for a transport system driven exclusively by the transmembrane electrochemical potential for Na+.

Early expression of β- and γ-subunits of epithelial sodium channel during human airway development

2000 ◽  
Vol 278 (1) ◽  
pp. L177-L184 ◽  
Author(s):  
Dominique Gaillard ◽  
Jocelyne Hinnrasky ◽  
Sylvie Coscoy ◽  
Paul Hofman ◽  
Michael A. Matthay ◽  
...  
Keyword(s):  
Human Lung ◽  
Immunohistochemical Localization ◽  
Fluid Composition ◽  
Clara Cells ◽  
Ciliated Cells ◽  
Membrane Protein Complex ◽  
Large Airways ◽  
Early Expression ◽  
Polyclonal Antisera ◽  
Human Airways

The amiloride-sensitive epithelial Na+channel (ENaC) is an apical membrane protein complex involved in active Na+ absorption and in control of fluid composition in airways. There are no data reporting the distribution of its pore-forming α-, β-, and γ-subunits in the developing human lung. With use of two different rabbit polyclonal antisera raised against β- and γ-ENaC, immunohistochemical localization of the channel was performed in fetal (10–35 wk) and in adult human airways. Both subunits were detected after 17 wk of gestation on the apical domain of bronchial ciliated cells, in glandular ducts, and in bronchiolar ciliated and Clara cells. After 30 wk, the distribution of β- and γ-subunits was similar in fetal and adult airways. In large airways, the two subunits were detected in ciliated cells, in cells lining glandular ducts, and in the serous gland cells. In the distal bronchioles, β- and γ-subunits were identified in ciliated and Clara cells. Ultrastructural immunogold labeling confirmed the identification of β- and γ-ENaC proteins in submucosal serous cells and bronchiolar Clara cells. Early expression of ENaC proteins in human fetal airways suggests that Na+ absorption might begin significantly before birth, even if secretion is still dominant.

Potassium conductance in rabbit esophageal epithelium

1993 ◽  
Vol 265 (1) ◽  
pp. G28-G34 ◽  
Author(s):  
W. E. Khalbuss ◽  
R. Alkiek ◽  
C. G. Marousis ◽  
R. C. Orlando
Keyword(s):  
Steady State ◽  
Epithelial Cells ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Potassium Conductance ◽  
Short Circuit Current ◽  
Sodium Absorption ◽  
High K ◽  
Esophageal Epithelial Cells ◽  
Apical Membranes

K+ conductance in apical and basolateral cell membranes of rabbit esophageal epithelial cells was investigated within intact epithelium by impalement with conventional microelectrodes from luminal or serosal sides. Under steady-state conditions, K+ conductance was demonstrated in basolateral, but not apical, membranes by showing 1) membrane depolarization upon exposure to either solutions high in K+ (20-65 mM) or containing Ba2+, tetraethylammonium, or quinine, and 2) a resistance ratio that increased on exposure to high K+ solution and decreased on exposure to Ba2+, quinine, and tetraethylammonium. From exposures to high K+, the apparent K+ transference number and electromotive force generated at the basolateral membrane were calculated and found to be 0.42 +/- 0.01 and -83 +/- 3 mV, respectively. Furthermore, basolateral K+ conductance was shown to be important for maintaining resting net transepithelial Na+ absorption in that high K+ or barium inhibited the transepithelial potential difference and short-circuit current of Ussing-chambered epithelia. We conclude that under steady-state conditions the basolateral, but not apical, membranes of esophageal epithelial cells contain a K(+)-conductive pathway and that this pathway is important for active sodium absorption.

scholarly journals Mechanical Fault Detection on Electrical Machine: Thermal Analysis of Small Brushed DC Motor with Faulty Bearing

2018 ◽  
Vol 225 ◽  
pp. 05012
Author(s):  
Abbas A. Wahab ◽  
N. Fatimah Abdullah ◽  
M.A.H. Rasid
Keyword(s):  
Thermal Analysis ◽  
Steady State ◽  
Direct Current ◽  
Dc Motor ◽  
Temperature Data ◽  
Electrical Machine ◽  
Financial Loss ◽  
Data Logger ◽  
Steady State Temperature ◽  
Using Data

Direct current motors (DC motor) are used in the small electric devices commonly. DC motor are cheap and easy to install, thus their popularity. Despite the popularity, faults occur which make diagnosis and detection of faults very important. It avoids financial loss and unexpected shutdown operation causes by these faults. This paper presents an analysis of temperature profile of the much famous small Brushed DC motor with a faulty bearing. The temperature data of healthy DC motor and DC motor with faulty bearing were measured by thermocouple and recorded using data logger in real time until steady state temperature, under different load. The analysis on the steady state temperature allow to conclude that bearing fault can clearly be recognised through characteristics temperature difference with a healthy motor.

scholarly journals Chlamydia pneumoniae Resists Antibiotics in Lymphocytes

2003 ◽  
Vol 47 (6) ◽  
pp. 1972-1975 ◽  
Author(s):  
Hiroyuki Yamaguchi ◽  
Herman Friedman ◽  
Mayumi Yamamoto ◽  
Keigo Yasuda ◽  
Yoshimasa Yamamoto
Keyword(s):  
Epithelial Cells ◽  
Bacterial Growth ◽  
Chlamydia Pneumoniae ◽  
Inflammatory Diseases ◽  
Lymphoid Cells ◽  
Infection Model ◽  
Chronic Inflammatory Diseases

ABSTRACT Chlamydia pneumoniae infection of lymphocytes in blood has been well documented, and it is apparent that control of this pathogen in these cells may be critical in the development of chronic inflammatory diseases associated with infection by this bacterium. The activity of antibiotics against C. pneumoniae in lymphocytes was assessed in this study by utilizing an in vitro infection model with lymphoid cells. The results obtained indicated that although all of the antibiotics tested showed remarkable activity against bacterial growth in epithelial cells, C. pneumoniae in lymphocytes was less susceptible to antibiotics than was bacterial growth in epithelial cells, which are widely used for the evaluation of anti-C. pneumoniae antibiotics.

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