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Biomedical subjects

I F Ueki

Publications and source records attributed to I F Ueki.

At least 37 records · Page 2Linked to original sources
PubMed1992

Interleukin-8 induces neutrophil accumulation but not protease secretion in the canine trachea.

The neutrophil enzyme elastase is a potent secretagogue of airway secretory cells, and elastase is present in high concentrations in sputum of patients with hypersecretion (e.g., cystic fibrosis, bronchiectasis). Interleukin-8 (IL-8), a recently discovered cytokine with potent neutrophil chemotactic properties in vitro, is also found in the sputum of these patients. We used an isolated tracheal segment in dogs in vivo to study the effect of IL-8 in causing neutrophil accumulation, elastase release, and secretion (by measuring lysozyme concentrations) in the luminal superfusate. IL-8 caused a potent time-dependent neutrophil accumulation at between 3 and 6 h. The effect was significant at 10(-9) and maximum at 10(-8) M. No increase in free elastase, cathepsin G, or lysozyme was detected in the superfusate. Thus, in contrast to previous studies showing that ragweed antigen causes the accumulation of neutrophil elastase which in turn causes lysozyme secretion, IL-8 causes neutrophil accumulation without granule secretion (or subsequent secretagogue activity). The findings were confirmed with dog and human neutrophils in vitro.

Animals↗
PubMed1991

Immunocytochemical localization of arachidonate 15-lipoxygenase in erythrocytes, leukocytes, and airway cells.

In reticulocytes, the enzyme 15-lipoxygenase (15-LO) is believed to contribute to cellular differentiation, and in leukocytes and airway cells 15-LO generates inflammatory mediators. The recent availability of antibodies to 15-LO now allows us to determine which specific cells contain the enzyme, to characterize its subcellular localization, and to determine its expression at the translational level. A polyclonal antibody to recombinant human reticulocyte 15-LO was used with a standard immunofluorescent technique. In rabbit red blood cells, fluorescence appeared during the course of anemia. Early reticulocytes did not fluoresce, but more mature reticulocytes showed increased fluorescent intensity. Late reticulocytes contained little fluorescence. Among human leukocytes, only eosinophils fluoresced. In human trachea, 15-LO immunofluorescence was localized to epithelial cells, and both basal and ciliated cells fluoresced. In all cells studied, fluorescence was localized to the cytoplasm and was variable in degree among cells in each preparation. We conclude that the 15-LO of airway cells and eosinophils is immunologically related to the reticulocyte 15-LO. Furthermore, the variable fluorescence among cells (e.g., in epithelium) and during development (e.g., reticulocytes) suggests a role of 15-LO in cell growth and development.

Animals↗
PubMed1990

Recombinant neutral endopeptidase attenuates substance P-induced plasma extravasation in the guinea pig skin.

To determine whether exogenously administered neutral endopeptidase (NEP; enkephalinase, EC 3.4.24.11) inhibits the substance P-induced increase in vascular permeability in the skin, we examined the effects of recombinant human NEP on plasma extravasation induced by intradermal injection of substance P in guinea pig skin. Injection of substance P (2.5 X 10(-8) M) induced significant plasma extravasation in the skin (53 +/- 4 mm2 of Evans blue extravasation; mean +/- 1 SEM). In vitro incubation of substance P with recombinant human NEP prior to injection prevented the substance P-induced plasma extravasation in the skin in a dose-dependent fashion. Intradermal preinjection of recombinant human NEP partially inhibited plasma extravasation induced by subsequent injection of substance P (52 +/- 9% of the control without NEP). The H1 and H2 histamine antagonists pyrilamine and cimetidine, and a muscarinic antagonist, atropine, had no effects on substance P-induced responses. Two products of substance P degradation by NEP containing the carboxy-terminal portion, substance P7-11 and substance P8-11, were also without effect. These findings suggest that recombinant human NEP can attenuate substance P-induced increases in vascular permeability in guinea pig skin and, therefore, may be useful in treating dermatologic disorders in which abnormal responses to substance P or other neuropeptides cleaved by NEP may occur.

Animals↗
PubMed1989

Release of cyclooxygenase products from primary cultures of tracheal epithelia of dog and human.

Release of cyclooxygenase products from primary cultures of dog or human tracheal epithelium was measured by radioimmunoassay. In both species, bradykinin, platelet-activating factor (PAF), and A23187 (a calcium ionophore) caused increases in the rate of release of prostaglandin (PG) E2 and smaller increases in PGF2 alpha, 6-keto-PGF1 alpha, and thromboxane B2 output. Isoproterenol, vasoactive intestinal peptide (VIP), methacholine, and leukotrienes C4 and D4 had no effect on release of these cyclooxygenase products. Gas chromatography-mass spectrometry showed that the ratio of PGE2 to PGD2 released from dog cells by A23187 was 30:1. Short-circuit current across dog cells was stimulated by bradykinin, A23187, PAF, VIP, methacholine, and isoproterenol. Only the responses to bradykinin and A23187 were reduced by pretreatment with indomethacin.

Animals↗
PubMed1989

Neutral endopeptidase modulates tachykinin-induced increase in vascular permeability in guinea pig skin.

To determine the regulatory role of neutral endopeptidase (NEP) in the tachykinin-induced increase in vascular permeability, we examined the effects of NEP inhibitors and of other protease inhibitors on plasma extravasation induced by intradermal injection of substance P, neurokinin A, and neurokinin B in guinea pig skin. The three tachykinins induced plasma extravasation in concentration-dependent fashions. A significant NEP activity was found to be present in the guinea pig skin. The tachykinin-induced responses were increased by the NEP inhibitors phosphoramidon and thiorphan. However, other protease inhibitors, including a kininase II inhibitor, did not affect the response. We conclude that NEP modulates the tachykinin-induced increase in vascular permeability in the skin.

Animals↗
PubMed1988

Effect of human eosinophil major basic protein on ion transport in dog tracheal epithelium.

Eosinophil major basic protein (MBP) is a granule-associated cytotoxic protein found in sputum and deposited on airway tissues of patients with acute asthma. We therefore studied the effect of human MBP on ion transport in dog tracheal epithelium. We mounted the posterior tracheal membranes of mongrel dogs in Ussing chambers and measured potential differences across the membranes and short-circuit current. Using 22Na+ and 36Cl- as tracers, we determined net ion movements. The addition of MBP (5 X 10(-6) M) to the mucosal, but not to the serosal, side of the membranes produced an increase in short-circuit current from 2.25 +/- 0.19 (mean +/- SE) to 2.78 +/- 0.23 muEq.cm-2h-1 (p less than 0.0001) and in net chloride secretion from 1.57 +/- 0.22 to 2.31 +/- 0.24 muEq.cm-2h-1 (p less than 0.01). There was no change in net sodium movement. Pretreatment with indomethacin (10(-5) M) attenuated, but did not abolish, the increase in short-circuit current. After exposure to MBP, prostaglandin E2 release into the serosal bathing solution increased from 10.0 +/- 4.2 to 17.0 +/- 6.9 ng.cm-2h-1 (p less than 0.05). The results of this study indicate that MBP simulates prostaglandin E2 production and chloride secretion by dog tracheal epithelium. Thus, eosinophils in the airways, through release of MBP, may affect mucociliary clearance by changing the volume and composition of respiratory tract fluid.

Animals↗
PubMed1988

Stimulation of Cl secretion by neurokinin A and neurokinin B in canine tracheal epithelium.

We studied the effects of neurokinin A (NKA) and neurokinin B (NKB), the mammalian-derived tachykinins, on the electrical and ion transport properties of canine tracheal epithelium. Both tachykinins dose-dependently increased short-circuit current (Isc) when added to the mucosal (NKA: delta Isc(max) = 24.2 +/- 2.4 microA/cm2, KD = 9 nM; NKB: delta Isc(max) = 1.42 +/- 2.2 microA/cm2, KD = 32 nM) or submucosal (NKA: delta Isc(max) = 10.5 +/- 1.2 microA/cm2, KD = 45 nM; NKB: delta Isc(max) = 2.2 +/- 1.4 microA/cm2, KD = 80 nM) bath. Isc responses to mucosal addition of tachykinins consisted of transient and subsequent steady-state components, whereas submucosal addition elicited only steady-state responses. Inhibition of Cl transport with bumetanide or substitution of Cl reduced the maximal changes in Isc. In paired tissues, NKA increased net 36Cl flux toward the mucosa from 1.83 +/- 0.49 to 2.71 +/- 0.46 mu eq.cm-2.h-1 (p less than 0.05), without affecting net 22Na flux toward the submucosa. The increases in Isc induced by tachykinins were not modified by prior tissue incubation with phentolamine, propranolol, atropine, tetrodotoxin, or indomethacin, but were effectively inhibited by (D-Pro2, D-Trp7,9)substance P. The cyclic AMP (cAMP) levels in the surface epithelium were increased by the addition of NKA and NKB. These findings suggest that NKA and NKB selectively stimulate the secretion of Cl across canine tracheal epithelium, probably by acting directly on the tachykinin receptors, and that these effects are associated with the increased production of intracellular cAMP.

Animals↗
PubMed1987

Effect of macrophage stimulation on parasympathetic airway contraction in dogs.

The effect of lung macrophages stimulated with calcium ionophore on parasympathetic contractile response of canine bronchial rings was studied. Macrophages augmented the contraction induced by electrical field stimulation, an effect that was inhibited by indomethacin and by SQ29548, a thromboxane A2 receptor antagonist, but had no effect on the contractile response to exogenous acetylcholine. These results suggest that macrophage-derived thromboxane A2 facilitates cholinergic neurotransmission prejunctionally in airway smooth muscle.

Animals↗
PubMed1987

Platelet aggregation increases cholinergic neurotransmission in canine airway.

To determine whether thromboxane A2 released from aggregating platelets increases the contractile response of airway smooth muscle to cholinergic nerve stimulation and, if so, what the mechanism of action is, we studied in vitro bronchial segments from dogs under isometric conditions. The contractile responses to electrical field stimulation at 30 s and 1 min after the addition of autologous platelets were increased by 11.1 +/- 3.2 (SD) and 20.7 +/- 5.4%, respectively, and were accompanied by the release of thromboxane A2. These effects were inhibited either by pretreatment of platelets with indomethacin or by addition of the thromboxane A2 receptor antagonist SQ 29548. Likewise, the thromboxane A2 mimetic U 46619, in subthreshold doses (i.e., insufficient to increase base-line tension), increased electrical field stimulation-induced contraction by 18.7 +/- 4.8%. The increase was greater in the presence of a concentration of physostigmine that did not cause spontaneous contraction and was blocked by SQ 29548 but not by hexamethonium or by phentolamine. Methacholine-induced contractions were unaffected by U 46619. These results indicate that aggregating platelets, by releasing thromboxane A2, increase the airway contractile response to neural stimulation probably by the accelerated release of acetylcholine.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1986

Alteration of chloride secretion across canine tracheal epithelium by lipoxygenase products of arachidonic acid.

We examined whether the leukotrienes (LT) B4, C4, D4, and E4, and 5-, 12-, and 15-hydroxyeicosatetraenoic (HETE) acids alter the electrical properties of canine tracheal epithelium. Short-circuit current (ISC) increased by 20.3 +/- 4.3 and 25.9 +/- 6.5 microA/cm2 after LTC4 and LTD4 addition, was unchanged following LTB4, LTE4, 5-, or 15-HETE addition, and was decreased by 10 +/- 3% after 12-HETE addition. LTC4- and LTD4-induced increases in ISC were dependent on the presence of Cl and were equal to the increases in net 36Cl flux toward the mucosa. The cyclooxygenase inhibitor indomethacin (10(-5) M) or the phospholipase inhibitor mepacrine (10(-5) M) diminished increases in ISC. The release rate of prostaglandins E2 and F2 alpha and thromboxane B2 rose from 8.2 +/- 2.3, 2.3 +/- 0.5, and 1.1 +/- 0.5 to 15.5 +/- 3.3, 6.0 +/- 1.4, and 4.0 +/- 0.8 ng . cm-2 . h-1, respectively, after LTC4 addition, and from 6.9 +/- 1.4, 2.5 +/- 1.1, and 1.7 +/- 1.3 to 20.2 +/- 3.1, 10.5 +/- 3.1, and 5.2 +/- 2.4 ng . cm-2 . h-1, respectively, after LTD4 addition. The release rates of 6-keto-prostaglandin F1 alpha were unchanged. A thromboxane A2 mimetic, U46619, failed to increase ISC and thromboxane synthetase inhibitors OKY-046 and dazmegrel failed to inhibit the induced increases in ISC, suggesting that thromboxane has little effect on ISC. Thus lipoxygenase products of arachidonic acid can modulate Cl secretion by the canine tracheal epithelium and do so through the release of cyclooxygenase products, including prostaglandins E2 and F2 alpha.

Animals↗
PubMed1986

O3-induced change in bronchial reactivity to methacholine and airway inflammation in humans.

The increase in airway responsiveness induced by O3 exposure in dogs is associated with airway epithelial inflammation, as evidenced by an increase in the number of neutrophils (polymorphonuclear leukocytes) found in epithelial biopsies and in bronchoalveolar lavage fluid. We investigated in 10 healthy, human subjects whether O3-induced hyperresponsiveness was similarly associated with airway inflammation by examining changes in the types of cells recovered in bronchoalveolar lavage fluid obtained after exposure to air or to O3 (0.4 or 0.6 ppm). We also measured the concentrations of cyclooxygenase and lipoxygenase metabolites of arachidonic acid in lavage fluid. We measured airway responsiveness to inhaled methacholine aerosol before and after each exposure and performed bronchoalveolar lavage 3 h later. We found more neutrophils in the lavage fluid from O3-exposed subjects, especially in those in whom O3 exposure produced an increase in airway responsiveness. We also found significant increases in the concentrations of prostaglandins E2, F2 alpha, and thromboxane B2 in lavage fluid from O3-exposed subjects. These results show that in human subjects O3-induced hyperresponsiveness to methacholine is associated with an influx of neutrophils into the airways and with changes in the levels of some cyclooxygenase metabolites of arachidonic acid.

Adult↗
PubMed1986

Airway hyperresponsiveness induced by platelet-activating factor: role of thromboxane generation.

The effect of platelet-activating factor (acetyl glyceryl ether phosphorylcholine; PAF), a potent inflammatory mediator, on airway responsiveness was studied. In six dogs airway responsiveness was determined by measuring the provocative concentration of acetylcholine aerosol that increased total pulmonary resistance (RL) by 5 cm H2O X L-1 X s, before and after inhalation of PAF (1 mg). PAF caused a 2.3-fold increase in RL (P less than .001) that lasted approximately 30 min. Airway hyperresponsiveness was maximal at 3 hr (mean 3.7-fold increase, P less than .001), persisted at 6 hr (P less than .005) and disappeared by 24 hr. Inhalation of 0.9% NaCl had no effect on RL or on responsiveness. PAF caused an 8-fold increase in neutrophil recovery in bronchoalveolar lavage fluid at 3 hr. OKY-046, a thromboxane synthetase inhibitor, inhibited PAF-induced bronchoconstriction and hyperresponsiveness but did not alter the increase in neutrophil recovery. We tested the specificity of the effect of OKY-046 on the release of cyclooxygenase products from canine neutrophils in vitro; OKY-046 suppressed PAF-induced generation of thromboxane and caused a small increase in prostaglandin F2 alpha release. The studies suggest that the airway hyperresponsiveness induced by PAF may depend on thromboxane generation.

Animals↗
PubMed1985

Bradykinin stimulates Cl secretion and prostaglandin E2 release by canine tracheal epithelium.

Bradykinin increased mean short-circuit current (Isc) when added either to the mucosal (KD = 1.1 nM; delta Imaxsc = 29.8 +/- 4.4 microA/cm2) or submucosal bath (KD = 108 nM; delta Imaxsc = 27.1 +/- 4.9 microA/cm2). Bumetanide or replacement of Cl reduced the maximal change in Isc. In paired tissues, the increase in net 36Cl flux toward the mucosa equaled the change in Isc. Net 22Na flux toward the submucosa was unchanged. Involvement of intramural nerves was ruled out because bradykinin-induced increases in Isc were not inhibited by phentolamine, propranolol, atropine, or tetrodotoxin. A direct action of bradykinin on the epithelium was also made probable by the autoradiographic demonstration of specific bradykinin binding sites. The antagonists of arachidonic acid metabolism, indomethacin and eicosa-5,8,11,14-tetraynoic acid, inhibited the increase in Isc induced by bradykinin. Finally, prostaglandin E2 release was significantly increased by submucosal addition of bradykinin, and this effect was abolished by pretreatment with indomethacin. We conclude that bradykinin stimulates Cl secretion in canine tracheal epithelium by increasing prostaglandin release.

Animals↗
PubMed1985

Leukotriene B4 induces airway hyperresponsiveness in dogs.

We studied the effect of leukotriene B4 aerosols on airway responsiveness to inhaled acetylcholine aerosols and on the cellular components and cyclooxygenase metabolites in bronchoalveolar lavage fluid in dogs. Inhalation of leukotriene B4 aerosols had no effect on resting total pulmonary resistance but increased airway responsiveness, an effect that was maximum in 3 h and that returned to control levels within 1 wk. Three hours after leukotriene B4, the number of neutrophils and the concentration of thromboxane B2 recovered in lavage fluid increased markedly. Pretreatment with the thromboxane synthase inhibitor OKY-046 prevented the increases in airway responsiveness and in thromboxane B2 but did not alter neutrophil chemotaxis. Thus we speculate that leukotriene B4 causes neutrophil chemotaxis and release of thromboxane B2, which increases airway responsiveness.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Autonomic regulation of viscoelasticity of cat tracheal gland secretions.

The purpose of this study was to determine whether various adrenergic agonists selectively regulate the viscoelastic properties of the stimulated secretions from airway submucosal glands. Nanoliter quantities of cat tracheal secretions before and during each of three stimuli were collected directly from a single submucosal gland with a micropipette, and the viscoelastic properties of the secretions were determined using a newly developed capillary microrheometer. Under unstimulated conditions (control), the measured values of apparent viscosity and elasticity of the secretions were more reproducible than the values obtained in previous studies in which samples were collected by other methods. After muscarinic (acetylcholine), alpha-adrenergic (phenylephrine), or beta-adrenergic (isoproterenol) stimulation, the submucosal gland's secretory rate was, in each case, greater than control. The viscoelastic properties of the secretions induced by muscarinic stimulation, however, were identical to control, whereas alpha-adrenergic stimulation produced secretions of a lower apparent viscosity, and beta-adrenergic stimulation produced secretions of a higher apparent viscosity and lower elasticity than control. Thus autonomic agonists selectively regulate the viscoelastic properties of submucosal gland secretions from cat trachea.

Acetylcholine↗
PubMed1982

Reflex stimulation of tracheal mucus gland secretion by gastric irritation in cats.

Our aim was to determine whether flow from the submucosal glands of the trachea is reflexly regulated by sensory stimuli from the stomach in the cat, and, if such a gastropulmonary reflex exists, what sensory and motor pathways are important. We found that mechanical stimulation of the gastric mucosa increased submucosal gland secretions from 7.9 +/- 0.7 to 17.4 +/- 1.7 nl/min (mean +/- SE, P less than 0.001). This effect was prevented reversibly by cooling both abdominal vagus nerves to -3 degrees C before stimulation and was restored by rewarming the nerves. The effect was prevented irreversibly by cutting both abdominal vagus nerves and was then mimicked by electrically stimulating the central cut end of one of the nerves. This increase in secretions caused by electrical stimulation of the nerve was prevented by administration of atropine sulfate before stimulation. We conclude that stimuli from the stomach reflexly affect the rate of submucosal gland secretion. The sensory limb of this reflex lies in the abdominal vagus nerves, and the motor pathways are mediated by cholinergic muscarinic receptors.

Animals↗