Asthma ; pathology ; Basophils ; physiology ; Bronchi ; pathology ; Humans ; Neutrophils ; physiology

The convective-diffusive problems of oxygen and carbon dioxide in human airway at normal respiratory status were studied theoretically in the present paper. The human airway was idealized as a bifurcated(two-branch) trachea tree, based on the understanding of the physiological structure of the human airway, and on Horsfield-Wanner optimization analysis about the trachea system status. It was assumed that the gases in the airway were incompressible, viscous fluid, due mainly to the characteristics of the low pressure drop and low rate of the gases within the human airway. One dimensional, non-steady convective-diffusive equations of oxygen and carbon dioxide were solved using Lax-Wendroff finite difference method, i.e., the so called three-legged finite difference method. The boundary conditions were set up according to the two different situations, respectively. The computational results showed the reasonable distributions of the concentration of oxygen and carbon dioxide in the human airway, respectively.
Bronchi ; physiology ; Carbon Dioxide ; metabolism ; Convection ; Diffusion ; Humans ; Models, Biological ; Oxygen ; metabolism ; Trachea ; physiology

The main physiological function of respiratory system is exchange of oxygen and carbon dioxide between atmosphere and blood. Its physiological process is closely related with air flow and transport in respiratory airway. This paper studies numerically the inspiratory flows in a two generation and a three generation bronchial airway. The numerical results of the two generation bronchi show that the present computations fit the available experiments very well. For three generation bronchi, no separation appears within the whole airway under normal breathing rate, which is contrary to the occurrence of separation at even low Reynolds number by the previous two dimensional models. Strong secondary flow phenomenon, skew and m-shaped main flow velocity profiles are found in the airways due to geometrical curvature and bifurcation. These increase shear stress acting on the inner wall as well as on the anterior and posterior wall in the bifurcating airways. In the end bronchi of the three generation airway, the mass flow rates in medial and lateral bronchi are unequal, and the mass flow ratio between the medial and the lateral bronchi is 1.2 at the flow conditions considered.
Bronchi ; anatomy & histology ; physiology ; Finite Element Analysis ; Humans ; Inhalation ; physiology ; Models, Biological

A three-element model of lumped parameter based on the statistic data of Weible's symmetric model and on the reference anatomic figures of the bronchial tree of the lungs has been proposed using the fluid network theory. It was assumed that the upper five or seven generations of the twenty-four generations of the respiratory airway are asymmetric, while the rest are symmetric. GEAR method was used to solve the ordinary differential equations. The pressure and flow rate distributions in different positions of the lungs during normal respiration and partial bronchial obstruction were compared, respectively. This model has great significance in finding out the air distribution in the human bronchial tree under various physiological and pathological conditions.
Airway Resistance ; Bronchi ; anatomy & histology ; pathology ; physiology ; Humans ; Models, Biological ; Respiration ; Respiratory Mechanics ; physiology

BACKGROUNDNon-heart-beating donor lung has been a promising source of lung transplantation. Many studies on non-heart-beating donor lungs are based on animal lung transplantation. In this study, we assessed by organ bath the effect of one-hour warm ischemia on the non-heart-beating donor lung in terms of the integrity of contractile and relaxant functions and tissue structures of pulmonic arteries and bronchi.

METHODSSixteen Swedish pigs were randomly classified into two groups: heart-beating donor group and 1-hour warm ischemia non-heart-beating donor group. Pulmonic and bronchial rings were taken from the isolated left lungs of the pigs. The pulmonic rings were stimulated by U-46619 (5.7 mol/L) and acetylcholine (10(-4) mmol/L) to assess the contractile abilities of smooth muscle and the endothelium-dependent relaxation response, respectively. As such, acetylcholine (10(-5) mmol/L) and natrium arachidonic acid (0.01%) were used to detect the contraction of bronchial smooth muscle and epithelium-dependent relaxation response. Meanwhile, the variances of precontraction tension of control groups were recorded to measure whether there was spontaneous relaxation during endothelium/epithelium-dependent relaxation course. Finally, papaverine solution (10(-4) mmol/L) was used to detect the non-endothelium/epithelium-dependent relaxant abilities of pulmonic and bronchial smooth muscles.

RESULTSThere was no significant difference in the tension values of precontraction of pulmonic rings (P > 0.05), endothelium-dependent relaxation (P > 0.05), precontraction of bronchial rings (P > 0.05) and epithelium-dependent relaxation (P > 0.05) between the heart-beating donor group and the 1-hour warm ischemia non-heart-beating donor group. And the pulmonic and bronchial rings of each subgroup B had no spontaneous relaxation. Finally, papaverine solution relaxed the smooth muscle of all the rings completely.

CONCLUSIONSThe results of this experiment suggest that the contractile and relaxant functions and tissue structures of pulmonic arteries and bronchi are not damaged after warm ischemia for 1 hour, and support the further study of non-heart-beating donor lung.

Animals ; Bronchi ; physiology ; Endothelium, Vascular ; physiology ; Lung Transplantation ; Pulmonary Artery ; physiology ; Swine ; Tissue Donors ; Vasodilation ; Warm Ischemia ; methods

OBJECTIVETo investigate the effect of annexin A2 (AnxA2) on epithelial growth factor receptor (EGFR)/nuclear factor-κB (NF-κB) signal transduction and mucin expression in human airway epithelial H292 cells treated with Mycoplasma pneumoniae (MP).

METHODSH292 cells were divided into control group, MP group, NC-siRNA+MP group, and AnxA2 siRNA+MP group. The cells in the MP group were incubated with 5 μg/mL MP antigen for 2 hours. The cells in the NC-siRNA+MP and AnxA2 siRNA+MP groups were transfected with NC-siRNA and AnxA2 siRNA for 24 hours, followed by MP antigen stimulation for 2 hours. The MTT method was used to measure cell viability; quantitative real-time PCR was used to measure the mRNA expression of AnxA2; Western blot was used to measure the protein expression of AnxA2, phosphorylated EGFR (p-EGFR), and phosphorylated p65 NF-κB (p-p65 NF-κB); ELISA was used to measure the secretion of mucin 5AC (MUC5AC) and mucin 5B (MUC5B).

RESULTSThe MP and NC-siRNA+MP groups had lower cell viability than the control group (P<0.05). The AnxA2 siRNA+MP group had higher cell viability than the MP and NC-siRNA+MP groups and lower cell viability than the control group (P<0.05). The MP and NC-siRNA+MP groups had significantly higher mRNA and protein expression of AnxA2 than the AnxA2 siRNA+MP group (P<0.05). Compared with the control group, the MP and NC-siRNA+MP groups had significant increases in the protein expression of p-EGFR, p-p65 NF-κB, MUC5AC, and MUC5B (P<0.05); the AnxA2 siRNA+MP group had lower protein expression than the MP and NC-siRNA+MP groups, but higher protein expression than the control group (P<0.05).

CONCLUSIONSAnxA2 is involved in the airway lesion induced by MP antigen via mediating EGFR/NF-κB signaling activation and mucin expression in human airway epithelial cells.

Annexin A2 ; physiology ; Bronchi ; physiology ; Cells, Cultured ; Epithelial Cells ; microbiology ; Humans ; Mucins ; analysis ; Mycoplasma pneumoniae ; pathogenicity ; NF-kappa B ; physiology ; Receptor, Epidermal Growth Factor ; physiology ; Signal Transduction ; physiology

OBJECT: To evaluate changes in the diameter of bronchi and pulmonary arteries during respiration. MATERIALS AND METHODS: The ratio of the diameter of matched inner bronchi and accompanying pulmonary arteries was calculated from full inspiration and expiration HRCT of healthy men. RESULTS: In 106 pairs of matched bronchi and pulmonary arteries, the brohchial-arterial ratios were 0.61+/-0.18(upper lung), 0.72+/-0.21(lower lung), and0.65+/-0.20(total) at full inspiration and 0.51+/-0.32(upper lung), 0.52+/-0.15(lower lung), and 0.51+/-0.26(total) atfull expiration HRCT, denoting a statistically significant increase in bronchial diameter of the entire lung atfull inspiration. The inner diameter of the bronchus was larger than the diameter of the accompanying pulmonary artery by 0.1% at full expiration and 8.5% at full inspiration. CONCLUSION: The result of this study would be helpful in understanding the physiology of the lung during respiration.
Adult* ; Arteries ; Bronchi ; Bronchiectasis ; Humans ; Lung ; Male ; Physiology ; Pulmonary Artery ; Respiration*

The research on cycle change form of the pressure and the wall shear in human upper respiratory tract can strengthen understanding of the characteristics of the airflow in the place and provide us with a scientific basis for analyzing the diffusion, transition and deposition patterns of aerosol there. In our study, we used large eddy simulation to emulate the pressure and wall shear in human upper respiratory tract in conditions of the low intensive respiratory patterns, and discussed the distributing disciplinarian of the pressure and wall shear in mouth-throat model and trachea-triple bifurcation. The results showed that the pressure gradient variation in human upper respiratory tract was mainly fastened from root of epiglottis to trachea. The minimum pressure at the interim of inspiration was a duplication of the interim of expiration, and located on the posterior wall of the glottis. The pressure gradient variation was evident on trachea and its fork. The wall shear changed with the velocity of the air flow, and its direction changed periodically with breath cycle.
Biomechanical Phenomena ; Bronchi ; physiology ; Computer Simulation ; Epiglottis ; physiology ; Humans ; Mouth ; physiology ; Nose ; physiology ; Pharynx ; physiology ; Pressure ; Pulmonary Ventilation ; physiology ; Respiratory Mechanics ; physiology ; Respiratory Physiological Phenomena ; Respiratory System ; Shear Strength ; Stress, Mechanical ; Trachea ; physiology

AIMTo investigate the role of three K+ channels-delayed rectifier K+ channel (Kv), large-conductance Ca(2+)-activated K+ channel (BK(Ca)) and ATP-sensitive K+ channel (K(ATP)) in the regulation of the resting and contracting tone of rat bronchial smooth muscle (BSM).

METHODSBy measuring the isometric tone of bronchial strips in vitro, the regulating effects of the three K+ channels on the tone of rat BSM were observed.

RESULTS(1) Kv blocker 4-aminopyridine (4-AP) caused concentration dependent contraction in resting bronchial strips, but BK(Ca) blocker tetraethylammonium (TEA) and K(ATP) blocker glibenclamide (Glib) had no such effects. (2) The bronchial epithelium had no effects on the contraction induced by 4-AP, but nifedipine, a Ca2+ channel blocker, significantly suppressed it. (3) Before or after treatment with 0.1 mmol/L histamine or 50 mmol/L KCl, administration of TEA (1 or 5 mmol/L) or 0.1 mmol/L 4-AP could significantly increase the contraction induced by histamine and KCl in bronchial strips. But Glib (10 micromol/L) had no effect on it.

CONCLUSIONNot BK(Ca) and K(ATP) but Kv participated in the regulation of the resting tone in rat BSM. The closure of BK(Ca) or Kv increased the contracting tone induced by histamine or KCl in rat BSM in vitro, but K(ATP) had no such effect on it.

4-Aminopyridine ; pharmacology ; Animals ; Bronchi ; drug effects ; In Vitro Techniques ; Male ; Membrane Potentials ; physiology ; Myocytes, Smooth Muscle ; physiology ; Patch-Clamp Techniques ; Potassium Channels ; physiology ; Rats ; Rats, Wistar

AIMTo investigate the role of delayed rectifier K+ channel (Kv), Ca2+ -activated K+ channel (K(Ca)) and ATP-sensitive K+ channel (K(ATP)) in the regulation of the resting and contracting tone of human control and passively sensitized bronchial smooth muscle (BSM).

METHODSThe regulating effects of the three K+ channels on the tone of human BSM (HBSM) were observed by measuring the isometric tone of bronchial rings in vitro.

RESULTS(1) The contraction of passively sensitized bronchial ring was significantly increased by histamine. (2) Kv blocker 4-aminopyridine (4-AP) caused concentration dependent contraction in resting bronchial rings of two groups, and the contraction sensitivity of the sensitized group rings was significantly stronger than that of control, that is, the negative logarithm of the drug concentration causing 50% of maximal effect (pD2) of the sensitized group rings were significantly larger than that of control rings, but there was no difference in the maximal effect (Emax) of two groups; Kca blocker tetraethylammonium (TEA) and K(ATP) blocker glibenclamide (Glib) had no such effects as those of 4-AP. (3) After pretreatment with 4-AP, the contraction of the control rings could significantly increased by histamine. After 4-AP treatment the Emax was significantly larger than that before 4-AP treatment. But the sensitized group rings had no such change, there was no significant difference in Emax before and after 4-AP treatment.

CONCLUSION(1) Not K(Ca) and K(ATP) but Kv participated in regulation of the resting tone of HBSM. (2) The activity of Kv decreased in bronchial smooth muscle passively sensitized by asthmatic serum compared with that of nonsensitized group. This change might be involved in the mechanism of asthma.

Asthma ; metabolism ; physiopathology ; Bronchi ; physiology ; Delayed Rectifier Potassium Channels ; physiology ; Female ; Humans ; Immune Sera ; Immunization, Passive ; In Vitro Techniques ; Male ; Middle Aged ; Muscle Tonus ; Muscle, Smooth ; physiology