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Experimental investigation of oscillatory flow through a symmetrically bifurcating tube

JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME 1998年第5期120卷 584-593页

作者： Peattie, RA Schwarz, W Trinity Coll Dept Engn Hartford CT 06106 USA Johns Hopkins Univ Dept Chem Engn Baltimore MD 21218 USA

To provide a quantitative description of the convection field of gas transport through the lung under both low and high-frequency ventilation conditions, volume-cycled, purely oscillatory flow has been investigated in a symmetrically bifurcating model bronchial bifurcation. Significant differences in the flow properties that developed as the Reynolds number varied from 750 to 950 and the dimensionless frequency varied from 3 to 12 are described At low frequency, the axial velocity field was found to approximate closely that of a steady pow through a bifurcation. However, even at alpha = 3, secondary velocity fields were confined to within a felv diameters of the bifurcation, with less than 10 percent of rite magnitude of the axial velocity. At high frequency they were still slower and more limited. these secondary velocity observations are discussed in terms of a physical mechanism balancing inviscid centripetal acceleration with viscous retardation. As the dimensionless frequency increased but the flow amplitude decreased, the magnitude of the axial drift velocity field was found to decrease. In addition, a burst of high-frequency velocity fluctuations was detected in both the axial and secondary velocity measurements in the parent tube, in low-frequency flow, during the deceleration phase of expiration. The position and timing of this burst suggest that it derives from the free shear layer in the parent tube. Stability criteria for the pow were therefore evaluated.

关键词：加速度支气管/生理学对流模型生物学示波测量法肺换气/生理学肺通气/生理学流变学潮气量气管/生理学黏度成年人人类

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Pulmonary stretch receptor discharges and vagal regulation of respiration differ between two mouse strains

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JOURNAL OF PHYSIOLOGY-LONDON 1999年第2期519卷 581-590页

作者： Burnet, H Hilaire, G UPR CNRS 9011 F-13402 Marseille 20 France

1. Experiments were performed on adult pentobarbitone-anaesthetized mice of the OF1 and the C3H/HeJ (C3H) strains, to analyse the regulation of respiration by pulmonary stretch receptors (PSRs). 2. Although the mean respiratory period, inspiratory and expiratory durations, and tidal volume did not differ significantly between the two strains, the inspiratory onset was drastically inhibited in OF1 mice but only slightly inhibited in C3H mice in response to tracheal occlusion performed at the very end of inspiration. 3. Low current electrical stimulation of the vague nerve induced inspiratory onset inhibition in both strains, suggesting that the weak inspiratory onset inhibition elicited by tracheal occlusion in C3H mice did not originate from a low sensitivity of the respiratory centres to PSRs. 4. During normal respiration, PSR firing rate increased with tidal volume, but reached significantly higher values in OF1 than C3H mice. During tracheal occlusion, PSR firing rate was significantly higher at the end of inspiration and during the first third of the occlusion period in OF1 than C3H mice. 5. The airway pressure resistance was significantly higher in OF1 than C3H mice. After abolishing the tracheo-bronchial muscle tone with atropine in OF1 mice, tracheal occlusions induced weak inspiratory onset inhibitions resembling the C3H mouse responses. 6. The possibility that differences in tracheo-bronchial tone between OF1 and C3H mice may lead to a greater PSR discharge and thus to a powerful inhibition on the OF1 medullary respiratory centres during tracheal occlusion is discussed.

关键词：气道阻塞/病理生理学支气管/神经支配支气管/生理学电刺激肺容量测定小鼠近交C3H 小鼠近交系肌平滑/神经支配肌平滑/生理学肺牵张感受器/生理学呼吸力学/生理学种特异性气管/神经支配气管/生理学迷走神经/生理学动物小鼠

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Pendelluft flow in symmetric airway bifurcations

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JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME 1998年第4期120卷 463-467页

作者： Feng, ZC Poon, CS MIT Dept Mech Engn Cambridge MA 02139 USA MIT Harvard MIT Div Hlth Sci & Technol Cambridge MA 02139 USA

We propose a mathematical model for pendelluft flow in a single airway bifurcation. The model is motivated by an apparatus used in an experimental study of the pendelluft by Ultman et al. (1988). We derive differential equations governing the fluid flow, which directly connect physiological parameters to the variables determining the pendelluft;this approach allows us to include nonlinearity in the model. If nonlinearity is neglected, our model is Identical to the R-I-C circuits used by previous investigators. If nonlinearity is retained, we show that pendelluft can occur even in perfectly symmetric airway bifurcations. For the specific apparatus used in the experiments of High et al. (1991), we demonstrate that two qualitatively different pendelluft flows can occur in the system.

关键词：气道阻力/生理学支气管/生理学弹性线性模型模型生物学非线性动力学数值分析计算机辅助试验预期值结果可重复性呼吸无效腔/生理学流变学

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Ethanol stimulates ciliary beating by dual cyclic nucleotide kinase activation in bovine bronchial epithelial cells

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AMERICAN JOURNAL OF PATHOLOGY 2003年第3期163卷 1157-1166页

作者： Wyatt, TA Forgèt, MA Sisson, JH Univ Nebraska Med Ctr Dept Internal Med Pulm & Crit Care Med SectNebraska Med Ctr 985300 Omaha NE 68198 USA Res Serv Med Ctr Dept Vet Affairs Omaha NE USA

Previously, we have shown that ethanol (ROH) stimulates a rapid increase in the ciliary beat frequency (CBF) of bovine bronchial epithelial cells (BBECs) via the activation of PKA. We have also shown that inhibitors of nitric oxide synthase block EtOH-stimulated increases in CBF. We hypothesize that EtOH acutely stimulates CBF via the activation of both PKA and PKG pathways. Using chemiluminescence detection of nitric oxide (NO), we directly measured increases in NO production in BBECs treated with 100 mmol/L of EtOH beginning at 25 minutes. Pretreatment of BBECs with guanylyl cyclase inhibitors, ODQ or LY83583, resulted in the inhibition of EtOH-stimulated CBF. Low concentrations (1 nmol/L) of cyclic nucleotide analogues do not stimulate CBF increases. However, a combination of both I nmol/L of 8Br-cAMP and 8Br-cGMP stimulates a significant increase over baseline CBF. This effect could be blocked by pretreating BBECs with inhibitors of either PKA or PKG. Very high concentrations of either 8Br-cAMP or 8Br-cGMP (greater than or equal to100 mumol/L) were required to cross-activate both PKA and PKG. This suggests that cross-activation of PKA by cGMP is not occurring at the concentrations (1 nmol/L) capable of stimulating CBF. 8-pCPT-cGMPS, an antagonist analogue to cGMP, blocked EtOH-stimulated PKA activity increases. These data support that EtOH-stimulated increases in CBF require the dual activation of both PKA (via cAMP) and PKG (via NO).

关键词：支气管/药物作用支气管/生理学细胞培养的纤毛/药物作用纤毛/生理学环AMP/代谢环AMP依赖性蛋白激酶类/代谢环GMP/类似物和衍生物环GMP/代谢环GMP/药理学环GMP依赖性蛋白激酶类/代谢酶激活酶抑制剂/药理学上皮细胞/药物作用上皮细胞/代谢上皮细胞/生理学乙醇/药理学鸟苷酸环化酶/拮抗剂和抑制剂一氧化氮/代谢恶二唑类/药理学喹恶啉类/药理学硫代核苷酸类/药理学动物牛

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Mechanisms of capsaicin- and lactic acid-induced bronchoconstriction in the newborn dog

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JOURNAL OF PHYSIOLOGY-LONDON 1999年第2期515卷 567-578页

作者： Nault, MA Vincent, SG Fisher, JT Queens Univ Dept Physiol Kingston ON K7L 3N6 Canada Queens Univ Dept Anaesthesia Kingston ON K7L 3N6 Canada Queens Univ Dept Paediat Kingston ON K7L 3N6 Canada

1. Capsaicin activation of the pulmonary C fibre vanilloid receptor (VR1) evokes the pulmonary chemoreflex and reflex bronchoconstriction. among potential endogenous ligands of C fibre afferents, lactic acid has been suggested as a promising candidate. We tested the hypotheses that (a) lactic acid behaves as a stimulant of C fibre receptors in the newborn dog to cause reflex bronchoconstriction, and (b) lactic acid causes reflex bronchoconstriction via the same pulmonary C fibre receptor mechanism as capsaicin using the competitive capsaicin/VR1 receptor antagonist capsazepine. 2. night heart injection of lactic acid caused a significant increase (47 +/- 8.0%) in lung resistance (R-L) that was atropine sensitive (reduced by 75%;P < 0.05), consistent with reflex activation of muscarinic efferents by stimulation of C fibre afferents. 3. Infusion of the competitive capsaicin antagonist capsazepine caused an 80% reduction (P < 0.01) in the control bronchoconstrictor response (41 +/- 8.5% increase in R-L) to right heart injections of capsaicin. The effects of capsazepine are consistent with reversible blockade of the VR1 receptor to abolish C fibre-mediated reflex bronchoconstriction. 4. Lactic acid-evoked increases in R-L were unaffected by VR1 blockade with capsazepine, consistent with a separate lactic acid-induced reflex mechanism. 5. We conclude that (a) putative stimulation of C fibres with lactic acid causes reflex bronchoconstriction in the newborn dog, (b) capsazepine reversibly antagonizes reflex bronchoconstriction elicited by right heart injection of capsaicin, presumably by attenuating capsaicin-induced activation of the C fibre 'capsaicin' receptor (VR1), and (c) capsazepine resistance of lactic acid-induced bronchoconstriction indicates that lactic acid evokes reflex bronchoconstriction by a separate mechanism, possibly via the acid-sensing ionic channel.

关键词：动物新生/生理学支气管/药物作用支气管/生理学支气管收缩/药物作用支气管收缩/生理学辣椒辣素/类似物和衍生物辣椒辣素/拮抗剂和抑制剂辣椒辣素/药理学乳酸/拮抗剂和抑制剂乳酸/药理学肺/药物作用肺/生理学肺顺应性/药物作用神经纤维/药物作用神经纤维/生理学受体药物/药物作用受体药物/生理学反射/药物作用反射/生理学动物狗

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MONITORING THE STATE OF THE HUMAN AIRWAYS BY ANALYSIS OF RESPIRATORY SOUND

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ACTA ASTRONAUTICA 1979年第9期6卷 1137-1151页

作者： HARDIN, JC PATTERSON, JL MED COLL VIRGINIA DEPT MEDRICHMONDVA 23219

A mechanism whereby sound is generated by the motion of vortices in the human lung is described. This mechanism is believed to be responsible for most of the sound which is generated both on inspiration and expiration in normal lungs. Mathematical expressions for the frequencies of sound generated, which depend only upon the axial flow velocity and diameters of the bronchi, are derived. This theory allows the location within the bronchial tree from which particular sounds emanate to be determined. Redistribution of pulmonary blood volume following transition from Earth gravity to the weightless state probably alters the caliber of certain airways and doubtless alters sound transmission properties of the lung. We believe that these changes can be monitored effectively and non-invasively by spectral analysis of pulmonary sound.

关键词：适应生理学支气管/解剖学和组织学支气管/生理学支气管收缩/生理学肺/解剖学和组织学肺/生理学肺疾病/诊断模型生物学呼吸力学/生理学呼吸音/分类呼吸音/生理学声音失重人类

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Induction of the cytochrome P450 gene CYP26 during mucous cell differentiation of normal human tracheobronchial epithelial cells

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MOLECULAR PHARMACOLOGY 2000年第3期58卷 483-490页

作者： Kim, SY Adachi, H Koo, JS Jetten, AM NIEHS Cell Biol Sect Pulm Pathobiol Lab NIH Res Triangle Pk NC 27709 USA

In this study, the expression of CYP26 is examined in relation to retinoid-induced mucosecretory differentiation in human tracheobronchial epithelial (HTBE) cells and compared with that in human lung carcinoma cell lines. In HTBE cells, retinoic acid (RA) inhibits squamous differentiation and induces mucous cell differentiation as indicated by the suppression of transglutaminase I and increased expression of the mucin gene MUC2. The latter is accompanied by increased expression of CYP26 mRNA. RA is required but not sufficient to induce RAR beta, CYP26, and MUC2 mRNA because induction is only observed in confluent but not in logarithmic cultures, suggesting that additional factors are critical in their regulation. CYP26 mRNA can be induced by the RAR-selective retinoid 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthracenyl)-benzoic acid (TTAB) but not by the RXR-selective retinoid SR11217 or the anti-activator-protein 1-selective retinoid SR11302. RAR alpha-, beta-, and gamma-selective retinoids are able to induce CYP26;this induction is inhibited by the RAR alpha-selective antagonist Ro41-5253. TTAB is able to induce CYP26 mRNA expression in only a few of the lung carcinoma cell lines tested. The lack of CYP26 induction in many carcinoma cell lines may relate to previously reported defects in the retinoid-signaling pathway. The induction of CYP26 correlated with increased metabolism of RA into 18-hydroxy-, 4-oxo-, and 4-hydroxy-RA. The latter metabolite was shown to be able to induce MUC2 and MUC5AC expression in HTBE cells. Our results demonstrate that in normal HTBE cells, CYP26 expression is closely associated with mucous cell differentiation and that many lung carcinoma cells exhibit increased RA metabolism and a defective regulation of CYP26.

关键词：抗肿瘤药/代谢抗肿瘤药/药理学支气管/细胞学支气管/生理学细胞分化/药物作用细胞分化/遗传学细胞系细胞色素P450酶系统/生物合成细胞色素P450酶系统/遗传学上皮细胞/细胞学上皮细胞/生理学基因表达调控/药物作用肺肿瘤 RNA 信使/生物合成受体维甲酸/代谢维甲酸/类似物和衍生物维甲酸/代谢维甲酸/药理学肿瘤细胞培养的人类

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SOME OBSERVATIONS ON THE FUNCTION OF PULMONARY STRUCTURES

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AMERICAN JOURNAL OF SURGERY 1955年第1期89卷 101-105页

作者： VANDAM, LD Boston Massachusetts USA

This discourse has concerned itself with some of the functions of pulmonary tissues other than those related directly to respiration. It was pointed out that the lungs contain anatomic structures which react in a characteristic manner to mechanical, pharmacologic and physiologic stimuli. Thus the so-called functional anatomy of the larynx, tracheobronchial tree, the blood supply and innervation of the lungs were presented. Reference was made to reactive phenomena which occur frequently during anesthesia and to reactions of pulmonic tissues in the prevention of infection.

关键词：支气管/生理学喉/生理学肺/生理学气管/生理学

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PARENCHYMAL GAS TENSIONS IN CANINE LUNG

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SCANDINAVIAN JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 1976年第3期10卷 243-246页

作者： HAVIA, T NIINIKOSKI, J UNIV TURKU DEPT SURGSF-20500 TURKU 50FINLAND

Lung parenchymal oxygen and carbon dioxide tensions were measured in dogs by using chronically implanted Silastic tubes. The effects of pulmonary arterial ligation and bronchial occlusion on lung tissue gases were recorded. Prevention of venous return to the lung increased parenchymal oxygen tension markedly. Obstruction of airways and bronchial arteries resulted in a profound decrease in parenchymal oxygenation.

关键词：支气管/生理学二氧化碳/血液二氧化碳/代谢肺/代谢氧/血液氧耗量分压肺动脉/生理学肺循环动物狗

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Nitric oxide and the developing airway

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AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY 2002年第6期283卷 L1190-L1191页

作者： Steinhorn, R Martin, RJ Case Western Reserve Univ Rainbow Babies & Childrens Hosp Div Neonatol Dept Pediat Cleveland OH 44106 USA Northwestern Univ Feinburg Sch Med Dept Pediat Chicago IL 60611 USA

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