Biomedical subjects

T Takishima

Publications and source records attributed to T Takishima.

At least 235 records · Page 13Linked to original sources

PubMed1990

Propagation and collision characteristics of calcium waves in rat myocytes.

In myocytes, local contractions occur spontaneously and propagate as traveling waves. We observed the waves in myocytes as local changes in fura-2 fluorescence and determined some characteristics of the wave. Myocytes were enzymatically isolated from rat left ventricles and incubated with 2 microM fura-2/AM for 60 min. Microscopic fluorescence images of myocytes were recorded with a high-sensitivity video camera. The images were digitally analyzed, frame by frame, and temporal changes in local fluorescence were displayed. With the excitation wavelength at 380 nm, the darker band propagates as the traveling wave. With the excitation wavelength at 340 nm, the wave appears brighter. With the isosbestic wavelength at 360 nm, the wave is not discernible. The waves are thus considered to be traveling waves of change in local cytoplasmic calcium ion concentration (calcium wave). Velocity, amplitude, and width of the calcium waves appeared to be fairly constant during their propagation. When two waves propagating in opposite directions collided, summation of the waves did not occur. After the collision both waves disappeared. These observations support the idea that the waves propagate by inducing calcium release from adjacent sarcoplasmic reticulum. Phenomena observed during the collision indicate that there is a refractory period after the calcium transient; spatially, a refractory zone exists in the wake of the wave.

Animals↗

PubMed1990

Sodium efflux from isolated submucosal gland in feline trachea.

We examined Na efflux, as an indicator of electrolyte (or water) secretion from isolated feline tracheal submucosal glands. After incubation with 22NaCl-containing KRB solution (pH 7.4) at 37 degrees C, the 22Na-loaded glands were transferred to a superfusion apparatus in which perfusate was continuously pumped to the glands at a flow rate of 2.5 ml/min and sampled at 18-s intervals for 10-15 min. After 5 min of perfusion, a pharmacological or electrical field stimulation (FS) was given to the isolated glands. The instantaneous rate constant was calculated by measuring the radioactivity (counts/min) of each effluent sample. The mean rate constant of the base-line 22Na efflux was 0.21 min-1, which fell significantly to 0.03 min-1 after treatment with ouabain. Both methacholine and phenylephrine significantly accelerated the 22Na efflux to 3.6-fold and 1.8 times base-line efflux, respectively. FS produced a significant increase in the rate constant, and the increase was abolished by pretreatment with ouabain or tetrodotoxin. Further, atropine or phentolamine significantly suppressed the FS-evoked increase in the rate constant to 76 and 84%, respectively, of the maximal response evoked by FS alone. These results indicate that Na efflux from feline tracheal submucosal glands, which is dependent on ouabain-sensitive Na-K-ATPase activity in the secretory cells, is stimulated by both cholinergic and alpha-adrenergic agonists.

Animals↗

PubMed1990

Mechanisms of decrease in cytoplasmic motility of alveolar macrophages during immediate asthmatic response in dogs.

To study the cytoplasmic motility (CM) of alveolar macrophages (AM) during immediate asthmatic response, we measured remanent filed strength (RFS) in dogs in vivo after Ascaris suum-antigen (AA) inhalation. Four days after instillation of ferrimagnetic particles (Fe3O4, 3 mg/kg) into the right lower lobe bronchus, RFS was measured at the body surface immediately after magnetization of the Fe3O4 particles by an externally applied magnetic field. RFS decreased with time because of particle rotation (relaxation). Relaxation is thought to be correlated to CM of AM (J. Appl. Physiol. 55: 1196-1202, 1983). AA inhalation increased respiratory resistance (Rrs) in 10 dogs (responders; P less than 0.01), and did not change Rrs in five dogs (nonresponders; P greater than 0.50). The relaxation rate (lambda 0) significantly decreased because of AA inhalation in responders (P less than 0.01), whereas lambda 0 did not change in nonresponders (P greater than 0.50). Intravenous injection of indomethacin or diclofenac sodium (5 mg/kg) 30 min before AA inhalation completely inhibited the decrease in lambda 0 induced by AA inhalation, although both drugs did not inhibit the increase in Rrs (P greater than 0.10). In in vitro experiments, AM (5 x 10(6) cells) cells) harvested by bronchoalveolar lavage showed a significant dose-dependent decrease in lambda 0 with prostaglandins (PG) E1 and E2. However, histamine and platelet-activating factor increased lambda 0 significantly (P less than 0.01), whereas PGD2, PGF2 alpha, PGI2, thromboxane A2, leukotrienes B4, C4, and D4, and AA itself were without effect (P greater than 0.50). Furthermore, PGE2 aerosols mimicked AA-induced effects on AM.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗

PubMed1990

Intracellular calcium concentration of acinar cells in feline tracheal submucosal glands.

We measured the intracellular free calcium ion concentration [( Ca2+]i) of acinar cells in isolated feline tracheal submucosal glands in response to secretagogues using the Ca2(+)-sensitive fluorescent dye fura-2. The secretagogues included cholinergic, adrenergic agonists, substance P (SP), and vasoactive intestinal polypeptide (VIP) which induce mucus glycoprotein secretion from feline tracheal submucosal glands. Methacholine (MCh) produced a significant increase in [Ca2+]i of up to 9.8 times that of control in a dose-dependent fashion at concentrations of 10(-8) to 10(-3) M. [Ca2+]i increase by MCh reached a peak within 30 s after stimulation and thereafter showed a sustained rise. In Ca2(+)-free medium, MCh produced an initial transient rise, which was less than 30% of that in a Ca2(+)-containing solution, and which lasted for 60 s with no prolonged sustained rise in [Ca2+]i. Atropine abolished MCh-evoked [Ca2+]i increase. Phenylephrine and SP produced a prolonged increase in [Ca2+]i without an initial transient increase. Phenylephrine (up to 10(-4) M) evoked an increase in [Ca2+]i by up to 240% that of control, which was abolished by prazosin. SP (up to 10(-4) M) also evoked an increase in [Ca2+]i by 155% that of control, which was abolished by atropine. By contrast, both isoproterenol (up to 10(-5) M) and VIP (up to 10(-5) M) failed to alter [Ca2+]i. These findings indicate that the mucus glycoprotein secretion evoked by muscarinic cholinergic, alpha-adrenergic agonist or SP can be mediated by intracellular Ca2+, whereas that by beta-adrenergic agonists or VIP cannot.

Animals↗

PubMed1990

Ozone increases susceptibility to antigen inhalation in allergic dogs.

To determine whether O3 exposure increased airway responsiveness to antigen inhalation, we studied airway responsiveness to acetylcholine (ACh) and Ascaris suum antigen (AA) before and after O3 in dogs both sensitive and insensitive to AA. Airway responsiveness was assessed by determining the provocative concentration of ACh and AA aerosols that increased respiratory resistance (Rrs) to twice the base-line value. O3 (3 parts per million) increased airway responsiveness to ACh in dogs both sensitive and insensitive to AA, and it significantly decreased the ACh provocation concentration from 0.541 +/- 0.095 to 0.102 +/- 0.047 (SE) mg/ml (P less than 0.01; n = 10). AA aerosols, even at the highest concentration in combination with O3, did not increase Rrs in dogs insensitive to AA. However, O3 increased airway responsiveness to AA in AA-sensitive dogs and significantly decreased log AA provocation concentration from 2.34 +/- 0.22 to 0.50 +/- 0.17 (SE) log protein nitrogen units/ml (P less than 0.01; n = 7). O3-induced hyperresponsiveness to ACh returned to the base-line level within 2 wk, but hyperresponsiveness to AA continued for greater than 2 wk. The plasma histamine concentration after AA challenge was significantly higher after than before O3 (P less than 0.01). Intravenous infusion of OKY-046 (100 micrograms.kg-1.min-1), an inhibitor of thromboxane synthesis, inhibited the O3-induced increase in responsiveness to ACh, but it had no effects on the O3-induced increase in responsiveness to AA and the increase in the plasma histamine concentration. These results suggest that O3 increases susceptibility to the antigen in sensitized dogs via a different mechanism from that of O3-induced muscarinic hyperresponsiveness.

Acetylcholine↗

PubMed1990

Aging effect on oxygen consumption of respiratory muscles in humans.

The first purpose of the present study was to develop a new method to examine oxygen consumption of respiratory muscles (VO2resp) in human subjects. The apparatus consists of an expandable dead space and a respirometer. When the dead space was increased at a constant rate (approximately 100 ml/min), minute ventilation (VE) and VO2resp increased gradually. Because the logarithm of VO2 was found to be approximately linearly related to VE, we characterized this relationship by the slope (logVO2/VE) and the intercept at VE = 0 (VO2met) of the semilog regression line. The second purpose of this study was to examine the relationship between VO2resp and aging. Six anthropometric and spirometric factors (age, height, weight, vital capacity, forced expiratory volume in 1 s, and body surface area) were analyzed in 37 normal subjects by simple and stepwise multiple regression analyses. We found a significant increase in logVO2/VE and a significant decrease in VO2met with age. In conclusion, 1) the present method is convenient to use, and we are able to study VO2resp over a wide range of ventilation without voluntary effort, and 2) age per se is one of the factors accounting for the observed increase in VO2resp with age.

Adult↗

PubMed1990

Nonadrenergic inhibitory nerves attenuate neurally mediated contraction in cat bronchi.

Effects of nonadrenergic and noncholinergic (NANC) inhibitory nerves on cholinergic neurotransmission were examined in isolated bronchial segments from cats in the presence of propranolol (10(-6) M) and indomethacin (10(-6) M) by use of electrical field stimulation (EFS) techniques. EFS caused contraction alone in tissues at the baseline tension and biphasic responses (contraction and relaxation) in tissues precontracted with 5-hydroxytryptamine. Contraction was abolished by atropine (10(-6) M), and relaxation was abolished by tetrodotoxin (10(-6) M). At the baseline tension, EFS at frequencies greater than 10 Hz inhibited the subsequent (4 min later) contraction induced by EFS at 1-5 Hz. EFS-induced inhibition was stimulus frequency dependent and reached maximum at 20 Hz. However, EFS at 20 Hz did not inhibit the subsequent contractile response to acetylcholine (10(-7) to 10(-3) M). Exogenously applied vasoactive intestinal peptide mimicked EFS-induced inhibitory effects, but substance P and calcitonin gene-related peptide did not. The inhibitory effect of EFS at 20 Hz was not altered by pyrilamine, cimetidine, naloxone, methysergide, phentolamine, BW755C, AF-DX 116, or removal of epithelium. These results imply that the NANC transmitter acts via presynaptic cholinergic receptors.

Animals↗

PubMed1990

Allergic sensitization in elderly patients with chronic obstructive pulmonary disease.

To study whether allergic sensitization occurs in elderly patients with chronic pulmonary obstructive disease (COPD), we examined serum IgE and skin test reactivity to allergens in three age-matched groups of normal subjects, and in patients with COPD and bronchial asthma (BA). Serum IgE was significantly higher in patients with COPD and BA than in normal subjects (p less than 0.05), and patients with COPD showed serum IgE levels as high as those of patients with BA. However, the skin test scores were significantly higher in patients with BA than in normal subjects and patients with COPD (p less than 0.05). Neither serum IgE nor skin test score significantly correlated with FEV1%, PaO2, PaCO2 or Brinkman's Index in any group (p greater than 0.20). These results suggest that allergic sensitization occurs in elderly patients with COPD and that symptoms associated with COPD may be partly due to allergic inflammation.

Asthma↗

PubMed1990

Effects of long-term pressure overload on regional myocardial glucose and free fatty acid uptake in rats. A quantitative autoradiographic study.

To investigate the effects of long-term pressure overload on regional myocardial substrate use, we performed quantitative autoradiography using 2-deoxy-D-[U-14C]glucose (14C-DG) and beta-methyl[1-14C]heptadecanoic acid (14C-BMHDA) in conscious rats with a 10-week ascending aortic constriction. Heart weight/body weight ratio increased by 27% in aortic-constricted rats as compared with sham-operated rats (p less than 0.01). Myocardial 14C-DG uptake increased (258 +/- 63 vs. 144 +/- 41 nCi/g, p less than 0.01, n = 6 for each group); however, 14C-BMHDA extraction decreased (251 +/- 69 vs. 342 +/- 75 nCi/g, p less than 0.05, n = 7 for each group) in aortic-constricted rats as compared with sham-operated rats. In sham-operated rats, both 14C-DG and 14C-BMHDA uptakes were higher in the left ventricular anterior and lateral walls as compared with the posterior wall or the interventricular septum. In aortic-constricted rats, 14C-DG uptake also increased in the interventricular septum, as well as in the left ventricular anterior and lateral walls, as compared with the posterior wall. There was, however, no regional difference in 14C-BMHDA extraction among these four regions. Myocardial blood flow distribution determined by 4-[N-methyl-14C]iodoantipyrine or myocyte width showed no regional variations among the four regions, either in aortic-constricted or sham-operated rats. Regional interstitial fibrosis was small in either group. The present study suggests that myocardial substrate uptake is altered nonhomogeneously, and that the nonhomogeneity is not because of regional variations in blood flow distribution, myocyte hypertrophy, or interstitial fibrosis. The results of angiotensin II-induced acute pressure overloading in other sham-operated rats, in which a remarkable increase in myocardial 14C-BMHDA extraction (n = 3, p less than 0.01) and no difference in 14C-DG uptake (n = 3) as compared with normotensive sham-operated rats were elicited, suggest that the findings in aortic-constricted rats are not direct responses to increased left ventricular pressure itself but rather should be explained by still unknown factors related to prolonged pressure overload.

Acute Disease↗

PubMed1990

Normalization of impaired coronary circulation in hypertrophied rat hearts.

We tested the hypothesis that impaired coronary autoregulation, decreased flow reserve, and diminished reactive hyperemic response in hypertrophied hearts with coronary arterial hypertension may be reversible after relief of pressure overload. In 4-week ascending aortic banded rats, in vivo peak systolic left ventricular pressure increased to 178 +/- 8 mm Hg (103 +/- 6 mm Hg in sham-operated control group). This increased pressure produced myocardial hypertrophy, and the left ventricular weight/body weight ratio was 46% above that of the control group. After the rats were killed, the coronary perfusion pressure-flow relations were obtained during resting conditions and maximal vasodilation after a 40-second period of ischemia in beating but nonworking isolated hearts perfused with Tyrode's solution with bovine red blood cells and albumin. In hearts from control rats, coronary autoregulation (i.e., a slight decrease in flow with reduction of pressure) was observed in the range of 50-100 mm Hg of perfusion pressure. A pronounced reactive hyperemic response was observed: a peak flow/resting flow ratio of 2.9 +/- 0.1 and a repayment ratio of 1.7 +/- 0.2 at 100 mm Hg of perfusion pressure. In hearts of banded rats the resting pressure-flow relation was rectilinear in the range of 25-175 mm Hg of perfusion pressure. Flow reserve and the time of reactive hyperemia to one half peak flow decreased at 50, 100, and 150 mm Hg of perfusion pressure compared with values in control rat hearts. Four weeks after debanding, peak systolic left ventricular pressure and cardiac hypertrophy had normalized. The impaired autoregulation, decreased flow reserve, and diminished reactive hyperemic response had completely reversed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Diameter change and pressure-red blood cell velocity relations in coronary microvessels during long diastoles in the canine left ventricle.

The objective of this study was to determine whether coronary vascular resistance remains constant during long diastoles and whether critical closure of arterial microvessels occurs at zero-flow pressure. For this purpose, we directly measured internal diameters and red blood cell velocities in arterial and venous coronary microvessels during long diastoles under maximal vasodilation. The epicardial coronary microcirculation was viewed in anesthetized, open-chest mongrel dogs through an intravital microscope equipped with a newly developed floating objective. Coronary microvascular diameters and red blood cell velocities were measured with high-speed cinematography. During maximal vasodilation (150 micrograms/kg body wt i.v. dilazep), long diastoles were induced by vagal nerve stimulation. Internal diameters of all small arteries and arterioles (n = 12) gradually declined with decreasing aortic pressure during long diastoles, and the reduction of the diameter was greatest when aortic pressure was less than 35 mm Hg. The mean internal diameter (88.8 +/- 52.2 microns) at minimal aortic pressure (19.2 +/- 6.4 mm Hg) was significantly less than that at an aortic pressure of 100 mm Hg (116.2 +/- 68.5 microns, p less than 0.01). The internal diameters of small veins and venules remained nearly constant during long diastoles. When red blood cell progression in coronary microvessels stopped at the nadir of aortic pressure, all arterial coronary microvessels remained open; that is, there was no evidence of "critical closure."(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Neuropeptide Y modulates vasoconstriction in coronary microvessels in the beating canine heart.

The purpose of this study was to determine whether neuropeptide Y has a direct vasoconstrictor effect at low doses, mimicking the physiological plasma concentration on the specific site(s) of coronary arterial microvessels in in situ beating canine left ventricles. Coronary microvessels were directly observed by means of an intravital microscope and video system equipped with a floating objective. Epi-illuminated fluorescence coronary microangiography was performed in open-chest anesthetized dogs (n = 14) to examine the changes in internal diameter of epimyocardial arterial microvessels. Flow velocity of fluorescently labeled microshperes in capillaries was also measured (n = 6). To eliminate secondary effects of neuropeptide Y on coronary microvessels via autonomic nervous modulation, experiments were conducted under pharmacological blockade of the regional autonomic nervous system by intracoronary injection of propranolol, 50 micrograms/kg; phentolamine, 100 micrograms/kg; and atropine, 5 micrograms/kg. Aortic pressure and heart rate were kept constant during the experiments. Intracoronary infusion of three different doses of neuropeptide Y (1, 10, and 100 pmol/kg/min) for 5 minutes significantly constricted small microvessels (less than 100 microns in diameter) (-5.2 +/- 1.4%, -8.5 +/- 1.5%, and -14.0 +/- 1.7%; p less than 0.05 versus before neuropeptide Y at each dose), medium microvessels (100-200 microns in diameter) (-5.5 +/- 1.6%, -10.6 +/- 1.8%, and -16.8 +/- 2.1%, p less than 0.05 versus before neuropeptide Y at each dose), and large microvessels (greater than 200 microns in diameter) (-3.6 +/- 0.6%, -5.8 +/- 0.8%, and -10.0 +/- 1.1%; p less than 0.05 versus before neuropeptide Y at each dose) in a dose-dependent manner. Capillary flow velocity was reduced by 17.2 +/- 3.1% by an intracoronary dose of 100 pmol/kg/min of neuropeptide Y (p less than 0.05). The present study indicates that low doses of neuropeptide Y exert a homogeneous direct vasoconstrictor effect on various sizes of coronary arterial microvessels and reduce capillary flow velocity. These results suggest that neuropeptide Y may play a physiological role in modulating coronary microvascular tone.

Animals↗

PubMed1990

Effect of nonadrenergic noncholinergic inhibitory nerve stimulation on the allergic reaction in cat airways.

To examine the effect of nonadrenergic noncholinergic (NANC) inhibitory nerve stimulation on the antigen inhalation with allergic animals, changes in pulmonary resistance (RL) and arterial plasma histamine concentration ([H]) caused by inhalation of Ascaris suum antigen were studied in five control (Group A) and five nerve-stimulated (Group B) cats, which were anesthetized and mechanically ventilated. All animals were actively sensitized with Ascaris antigen before the experiment. After cholinergic and beta-adrenergic blockade with intravenously administered atropine (3 mg/kg) and propranolol (2 mg/kg), inhalation of the antigen (1:100 dilution) was performed for 3 min. For Group B, bilateral cervical vagi were stimulated electrically for 1 min before the antigen inhalation and successively every 30 s until 5 min had passed from the onset of inhalation. RL and [H] were determined before, during, and after antigen inhalation in both groups. Baseline RL and [H] did not differ significantly between groups (16.3 +/- 2.2 (mean +/- SE) cm H2O/L/s and 14.0 +/- 0.7 ng/ml, respectively, for Group A; 14.4 +/- 1.3 and 15.6 +/- 2.7, respectively, for Group B). Increases in RL and [H] of Group B after the antigen inhalation were significantly depressed, compared with Group A (p less than 0.01 and p less than 0.05, respectively, two-way ANOVA). The increase in RL 5 min after antigen inhalation was 113 +/- 19% for Group A and 28 +/- 8% for Group B, and the increase in [H] at the same point was 36.3 +/- 9.1 ng/ml for Group A and 4.4 +/- 1.4 ng/ml for Group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗

PubMed1990

Direct inhibitory action of glucocorticoid on glycoconjugate secretion from airway submucosal glands.

The precise mechanism by which glucocorticoids inhibit airway mucus secretion is still unknown. To study directly the effect of glucocorticoid on submucosal gland secretion, we examined the effects of dexamethasone on the precursor uptake, biosynthesis, and release of mucus glycoprotein in isolated feline tracheal submucosal glands. Mucus glycoprotein release from isolated glands was estimated by measuring [3H]glucosamine-labeled trichloroacetic acid (TCA)-precipitable glycoconjugates secreted into the medium. Released glycoconjugate per hour per dry weight of gland tissue was less than 7% of the total intracellular content, where intracellular content is defined as total 3H activity in the dissolved gland tissue. Treatment with 10(-9) to 10(-5) M dexamethasone for 24 to 72 h significantly reduced basal glycoconjugate secretion up to 22% of control (a 78% decrease) in a dose-dependent fashion, whereas the total intracellular 3H content was reduced to 70% of control (a 30% decrease) with no statistically significant differences from controls. The ratio of released glycoconjugates to the total intracellular content decreased significantly to 31% of control (a 69% decrease) after the treatment with 10(-10) to 10(-5) M dexamethasone. Further, ratio of radioactivity of TCA-precipitable glycoconjugates in the dissolved gland tissue to the total intracellular 3H content increased from 40% in nontreated controls to 46% after the treatment with dexamethasone (10(-5) M). Dexamethasone also inhibited the glycoconjugate secretion stimulated by dibutyryl cyclic AMP and alpha- and beta-adrenergic agonists. Simultaneously, the ratio of released to total intracellular content also decreased significantly after dexamethasone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Oxygen radicals produce airway constriction and hyperresponsiveness in anesthetized cats.

Using 30 anesthetized cats, we examined whether oxygen radicals produce airway constriction or hyperresponsiveness. In one group, we administered aerosolized xanthine (0.1%) for 3 min followed by aerosolized xanthine oxidase (XO) (1 U/ml) for 5 min in order to generate oxygen radicals enzymatically in the airways. Pulmonary resistance (RL) instantaneously increased from 14.8 +/- 0.9 to 30.8 +/- 1.4 cm H2O/L/s (p less than 0.01). The increase in RL was significantly depressed by prior administration of polyethylene glycol-superoxide dismutase (PEG-SOD) or polyethylene glycolcatalase (PEG-CAT). In a second group, in order to examine changes in airway responsiveness, we studied acetylcholine (ACh) challenge before and 30, 60, and 120 min after inhalations of xanthine and XO. After xanthine-XO, the airways were hyperresponsive to ACh at 30 and at 60 min (p less than 0.05) but not at 120 min. The geometric means of ACh provocative concentrations that caused an increase in RL of 10 cm H2O/L/s above the baseline value before and 30, 60, and 120 min after xanthine-XO were 0.25, 0.045, 0.073, and 0.15%, respectively. The increase in responsiveness to ACh was significantly correlated with the increase in RL after xanthine-XO inhalation (r = 0.88, p less than 0.05). These data support the concept that oxygen radicals generated by xanthine-XO inhalation may induce bronchoconstriction and airway hyperresponsiveness.

Acetylcholine↗

PubMed1990

Eosinophil supernatant causes hyperresponsiveness of airway smooth muscle in guinea pig trachea.

To study the role of eosinophils in airway hyperresponsiveness, we studied the effect of supernatant obtained from activated eosinophils on the responses of isolated guinea pig tracheal smooth muscle segments to histamine. Eosinophils obtained from guinea pig peritoneal fluid were purified and activated with Ca2+ ionophore A23187 using a two-stage reaction. Supernatant obtained from different eosinophil cell numbers (3 x 10(5) to 10(7) cells) did not alter resting tension but potentiated the contractile response to histamine in a cell number-dependent fashion. Thus, at a cell number of 10(7), the supernatant decreased the mean (+/- SE) log histamine concentration producing 50% of maximum contraction significantly from a control value of -5.62 +/- 0.10 to -5.99 +/- 0.07 M (p less than 0.05). The potentiating effect of the supernatant (10(7) cells) was not altered by either removal of tracheal epithelium or by pretreatment with indomethacin when cells were activated. However, pretreatment with AA 861 completely inhibited the supernatant (10(7) cells)-induced potentiating effect associated with inhibition of leukotriene C4, D4, and E4 release in the supernatant. The concentrations of exogenous authentic leukotrienes chosen to match concentrations in the supernatant mimicked the supernatant-induced potentiating response to histamine. These results suggest that leukotrienes released from eosinophils cause hyperresponsiveness of airway smooth muscle in vitro.

Animals↗

PubMed1990

Production of tumor necrosis factor with IgE receptor triggering from sensitized lung tissue.

Mast cells and basophils have been known to play a central role in allergic inflammation through the release of chemical mediators by cross-linkage of IgE receptors. The IgE receptor triggering and calcium ionophore A23187 have also been shown to induce gene expression and production of tumor necrosis factor (TNF) by rat basophilic leukemia cells. In the present study, we examined whether IgE receptor triggering could induce gene expression and production of TNF in rat lung tissue. The lung tissue released not only histamine but also cytotoxic activity on L929 cells 2 and 4 h after incubation with dinitrophenyl conjugated to ovalbumin (DNP-OVA) following passive sensitization with anti-DNP monoclonal rat IgE antibody, whereas neither DNP-OVA nor anti-DNP IgE antibody could induce the cytotoxic activity when used solely. Calcium ionophore A23187 also could induce both histamine release and cytotoxic activity. These activities induced by IgE receptor triggering, A23187, and lipopolysaccharide were completely neutralized by preincubation with anti-mouse TNF-rabbit serum, but not with normal rabbit serum. Northern blot analysis using cDNA probe of mouse TNF demonstrated expression of TNF gene as early as 2 h after IgE receptor triggering. These data demonstrating that IgE receptor triggering induced gene expression and production of TNF in lung tissue suggest the participation of TNF in the pathogenesis of late asthmatic response through its biologic activities such as the attraction and activation of neutrophils and eosinophils.

Animals↗

PubMed1990

Effects of interleukin 3, interleukin 4, and fibroblasts on cultures of human lung mast cells in bronchoalveolar lavage fluids.

The effects of T cell factors, including interleukin (IL)-3 and IL-4, and fibroblasts on the growth and differentiation of human lung mast cells (MCs) obtained by bronchoalveolar lavage (BAL) were examined. The number of MCs identified by alcian blue-safranin staining was twice that of the control culture without conditioned medium (CM) when BAL cells were cultured for 2 weeks in RPMI 1640 containing 10% fetal calf serum and partially purified CM derived from PHA-stimulated lymphocytes. In the presence of both recombinant (r) IL-3 and rIL-4, the number of MCs was twice as high as the control without increase in the per-cell histamine content after 2 weeks' culture. In umbilical cord blood cultures, IL-3 plus IL-4 augmented basophilic cells about 20-fold more than the control when cultured for 2 weeks. In some cases, the percentage of safranin-positive MCs was about 2-5 fold greater, with 2-7 fold higher histamine content, when cultured for 10 days with CM and fibroblasts derived from human embryonic lung. However, in all BAL experiments, there was no increase in the total number of MCs after culture compared with the initial number of MCs, unlike the umbilical cord blood cultures. These results suggest that T cell factors, including IL-3 and IL-4, and fibroblasts may influence the phenotype and the survival of lung mast cells in BAL, whereas there was no evidence for the presence of MC precursors in BAL fluids.

Bronchoalveolar Lavage Fluid↗