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Results for “Mucociliary Clearance”

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PubMedDate not supplied

The effects of ethanol on mucociliary clearance.

Mucociliary clearance by the in vitro frog palate can be used as a model to study such clearance by mammalian lung. Frog palates bathed in Ringer's solution exhibited a constant mucociliary clearance rate for over 2 hr. When the bathing solution was exchanged for one containing ethanol, the mucociliary clearance rate was detectably inhibited by 300 mg/100 ml (mg%) ethanol and significantly inhibited by 400 (50%) and 500 mg% (67%) ethanol. At a concentration of 500 but not 200 mg%, ethanol significantly increased both the amount and the apparent viscosity of the frog palate mucus secreted in 1 hr. Mucus removed from palates bathed in Ringer's solution containing 500 mg% ethanol had no effect on the mucociliary clearance of palates bathed in Ringer's solution alone, and mucus from palates bathed in Ringer's solution alone failed to restore the mucociliary clearance of palates bathed in Ringer's solution containing 500 mg% ethanol. These results suggest that while mucus secretion and rheology are affected by ethanol, such changes in palate mucus do not account for the ethanol-induced inhibition of mucociliary clearance, but rather that the inhibition is the result of a ciliotoxic action of ethanol. Prior exposure of palates to histamine significantly attenuated the inhibitory effect of 500 mg% ethanol on mucociliary clearance, while 200 mg% ethanol significantly potentiated the inhibitory effect of dopamine. It is concluded that the neurohumoral environment of the ciliated epithelium in part determines the effect a given concentration of ethanol will have on mucociliary clearance.

Animals↗

PubMedDate not supplied

Tracheal resection and mucociliary clearance.

Mucociliary transport following tracheal resection and end-to-end anastomosis was evaluated in beagle dogs, using the movement of 99MTC labeled sodium pertechnetate solution as a marker. Preoperatively, mucociliary clearance was stable, but a three-fold decrease in tracheal mucus movement was found three days postoperatively. Clearance rates had returned to normal by 31 days postoperatively and remained stable over a ten week period of observation. By histological examination, normal ciliated epithelium was seen within six months following resection and anastomosis. Since up to 25% (4 cm or seven tracheal rings) of tracheal length was removed, significant longitudinal loss can take place without functional impairment of mucociliary clearance. Circumferential narrowing, however, was associated with a significant decrease in clearance.

Animals↗

PubMed2002

Effect of beta-adrenergic agonists on mucociliary clearance.

The mucociliary clearance apparatus, an important defense mechanism for clearing the lung of bacteria and foreign particulate matter, is a well-coordinated system consisting of airway secretory cells that produce a sol and gel (or mucus) fluid layer on the airway surface and ciliated cells that propel the mucus out of the lung towards the mouth. In vivo mucociliary clearance rates can be measured by following the rate of egress of deposited, radiolabeled markers by gamma camera. Short-acting beta-adrenergic agonists have been shown to enhance mucociliary clearance rates to varying degrees in patients with various lung diseases (eg, asthma, chronic bronchitis, and cystic fibrosis), although the enhancement is generally less than that seen in the normal lung. Limited data on the in vivo dose-response relationships of these mucociliary clearance effects suggest that larger doses are required for enhancement of mucociliary clearance than are needed for bronchodilatation. Little is known about chronic effects, but studies with dosing for up to a week also suggest an enhancement of mucociliary clearance, primarily by agonists that are lipophilic. Issues for future research include the effects of the newer long-acting beta-agonists, large versus small airway effects, and combination effects with other inhaled therapeutic agents (eg, steroids and ion-channel blockers).

Administration, Inhalation↗

PubMed1983

Mucociliary clearance in chronic sinusitis: related human nasal clearance and in vitro bullfrog palate clearance.

Nasal mucociliary clearance was measured in both healthy subjects and patients with chronic sinusitis using saccharin granule technique. Nasal mucociliary transit time (ST) was significantly slower in the patients with chronic sinusitis compared with that in controls (p less than 0.005). Nasal mucus collected from each nasal cavity was used for in vitro bullfrog palate clearance studies and compared to the in vivo nasal ST. Mucociliary clearance rate (MTR) on frog palate was 12.5 +/- 2.5 mm/min in the mucus from control subjects, 6.1 +/- 1.5 mm/min in the mucus from the patients. The difference was statistically significant (p less than 0.005). The MTR on frog palate in the patients whose nasal ST was within normal range was significantly slower than that in controls (p less than 0.005), but not significantly different from that in the patients whose nasal ST was over the normal range. These results suggest that the nasal mucous properties which decreased the mucociliary clearance on frog palate did not contribute to the mucociliary clearance of the patients who had a normal one. No significant correlation existed between MTR on frog palate and nasal ST in both control and chronic sinusitis. In chronic sinusitis patients, decelerated nasal ST was recovered significantly by normal saline nebulization compared with the value before the nebulization (p less than 0.01). None of the significant change of ST was observed in control before and after the nebulization.

Adolescent↗

PubMed1990

The effect of some preservatives used in nasal preparations on the mucus and ciliary components of mucociliary clearance.

Efficient mucociliary clearance is a function of the physical properties of the mucus coupled to appropriately functioning cilia and may be altered by substances affecting ciliary beat frequency (CBF). Therefore the effect of preservatives on CBF was investigated using a photoelectronic technique. Methyl-p-hydroxybenzoate, propyl-p-hydroxybenzoate, chlorbutol and chlorocresol inhibited beat frequency, an effect which was reversible upon rinsing out the first three compounds but not chlorocresol. The effect of chlorhexidine and phenylmercuric borate on CBF was complicated by an interaction with chloride ions in the media used. EDTA did not appear to be ciliotoxic, while the effect of benzalkonium chloride was variable. Thiomersal halted ciliary beating after 40-100 min. Mucociliary clearance may also be affected by an alteration of the physical properties of the mucus layer, therefore the effect of each compound on the rheological properties of purified pig gastric mucus glycoprotein was investigated. None of the preservatives significantly altered the viscoelastic properties of the gel, measured using dynamic techniques.

Animals↗

PubMed1995

Sidestream tobacco smoke exposure acutely alters human nasal mucociliary clearance.

Nasal mucociliary clearance (NMC) is a biomarker of nasal mucosal function. Tobacco smokers have been shown to have abnormal NMC, but the acute effect of environmental tobacco smoke (ETS) on nonsmokers is unknown. This study evaluated acute tobacco smoke-induced alterations in NMC in 12 healthy adults. Subjects were studied on 2 days, separated by at least 1 week. Subjects underwent a 60-min controlled exposure at rest to air or sidestream tobacco smoke (SS) (15 ppm CO) in a controlled environmental chamber. One hour after the exposure, 99mTc-sulfur colloid was aerosolized throughout the nasal passage and counts were measured with a scintillation detector. Six out of 12 subjects showed more rapid clearance after smoke exposure than after air exposure, and 3/12 had rapid clearance on both days. However, substantial decreases in clearance occurred in 3/12 subjects, all of whom had a history of ETS rhinitis. In two subjects, more than 90% of the tracer remained 1 hr after tracer administration (2 hr after smoke exposure). Understanding the basis for biologic variability in the acute effect of tobacco smoke on NMC may advance our understanding of pathogenesis of chronic effects of ETS.

Adult↗

PubMed1991

Measurement and pharmacology of mucociliary clearance.

Airways mucociliary clearance (MCC), which continuously removes inhaled particles and cellular debris from the lungs is impaired in a number of diseases such as bronchitis, asthma and cystic fibrosis. Regulation of MCC under normal conditions is not well understood and the cause of its impairment is ill defined. Animal models have been used to study the regulatory mechanisms of both mucus secretion and MCC and to ascertain the involvement of neural pathways. Cholinergic stimulation is a most effective means of enhancing MCC in molluscs, frogs and mammals including man. Recent data from mammals suggest that MCC is also regulated by neuropeptides either directly (substance P) or by facilitating the stimulatory effect of cholinergic agents. A better understand of basic regulatory mechanisms of MCC is vital to an understanding of its impairment in respiratory diseases.

Animals↗

PubMed1986

Effects of airborne pollutants on mucociliary clearance.

The mucociliary clearance system is a first line of defense against inhaled agents, and so its compromise can adversely affect health. The purpose of this paper is to provide a review of data on the effect of in vivo air pollutant exposures on the clearance of test particles from airways. Data from both animals and humans are compared whenever possible, so that estimates of human health effects may be made. Mechanisms of action are also discussed, presenting the view that for low level exposures, changes in secretions are probably responsible for most observed changes in clearance. The pollutants pertinent to this review are those that are common in the environment and most likely to have impacts on large numbers of people: sulfur oxides, sulfuric acid mist, O3, NO2, particulates, diesel exhaust, and cigarette smoke.

Air Pollutants↗

PubMed1987

Theophylline and mucociliary clearance.

Abnormal mucociliary transport is improvement by the action of theophylline, and this effect can be attributed to several mechanisms. The drug may directly and indirectly mediate the increase in the secretory output of bronchial glands, and this effect is enhanced by the vagal gastropulmonary reflex which is stimulated by the irritant action of theophylline on the stomach. Theophylline can increase the transepithelial secretion of fluid into the respiratory tract lumen by stimulating the chloride pump which is controlled by cyclic AMP. Ciliary motility is stimulated by theophylline; most of this effect is confined to the proximal part of the respiratory tree. However, much of the improvement in mucociliary clearance may be a consequence of the bronchodilation induced by theophylline, since the improved airway patency is generally a prerequisite for enhanced mucokinesis. Nevertheless, the multiple sites of action of theophylline in the respiratory tract suggests that this drug should be considered to be of significant value in any disorder characterized by mucostasis.

Aminophylline↗

PubMed2002

Increasing concentration of inhaled saline with or without amiloride: effect on mucociliary clearance in normal subjects.

Mucociliary clearance is determined by ciliary activity and rheology of airway surface liquid. To test the hypothesis that mucociliary clearance would increase after inhalation of an osmotically active agent that would increase the volume of airway surface liquid, we measured mucociliary clearance in 16 normal subjects after inhalation of varying tonicities of saline alone, and after pretreatment with a Na+ channel blocker (amiloride). Subjects inhaled vehicle (0.12% saline) or amiloride, followed by inhalation of 0.12, 0.9, or 7% saline. Subsequently, mucociliary clearance rates were measured by gamma scintigraphy of inhaled 99mTc Fe2O3. Mucociliary clearance of whole and peripheral lung was increased (approximately twofold) after inhalation of increasing concentrations of saline (p < 0.04). Pretreatment with amiloride increased mucociliary clearance rates (approximately twofold) after inhalation of 0.12 and 0.9% saline (p < 0.05), but not 7% saline. The rates of mucociliary clearance by pretreatment with amiloride and 7% saline alone (approximately 1.4% per minute) approached the rapid mucociliary clearance rates (approximately 2.0% per minute) reported in systemic pseudohypoaldosteronism, which has loss-of-function mutations of the epithelial Na+ channel and an increased volume of airway surface liquid. We conclude that maneuvers that increase the volume of airway surface liquid are associated with increased rates of mucociliary clearance in normal subjects.

Administration, Inhalation↗

PubMedDate not supplied

Nasal mucociliary clearance in perennial rhinitis.

Mucociliary clearance is one of the homeostatic systems of the respiratory mucosa. Alterations in mucociliary clearance have been extensively studied in asthma, but less frequently in allergic rhinitis. In rhinitis, conflicting results have arisen: while some authors reported no change, others noticed a reduction in nasal mucociliary clearance. The aim of this study was to compare the nasal mucociliary clearance in allergic and non-allergic patients with perennial rhinitis and a healthy control group. One hundred and three patients and 14 healthy control subjects were studied. Nasal mucociliary clearance was assayed with the saccharin test modified with a food dye to add a visual parameter. Patients were divided into allergic and non-allergic rhinitis according to the presence of three of the following factors: total serum IgE above 180 KIU/L, positive skin prick tests to a battery of standardized allergens relevant to Uruguay, family and personal history of atopic diseases, and blood eosinophilia above 450 cells/mm3. The aspect of the nasal mucosa was not considered for categorizing the patients. Fifty-seven patients (29 males, mean age: 22.2 years) with allergic perennial rhinitis and 46 patients (15 males, mean age: 24.8 years) with non-allergic perennial rhinitis were compared with 14 controls (6 males, mean age: 35 years). A significant difference in nasal mucociliary clearance was observed between the three groups, with a mean of 8.8 minutes for the controls, 10.27 minutes for allergic rhinitis and 11.73 minutes for non-allergic patients. We suggest that the differences we observed were due to changes in the rheology of nasal mucus as a consequence of the underlying inflammatory process in rhinitis.

Adult↗

PubMed1994

Influence of age, gender, and ethnicity on nasal mucociliary clearance function.

Nasal mucociliary clearance functions were measured in 46 healthy Chinese adult subjects (21 women and 25 men; age range, 27 to 75 years). A single droplet of Tc-99m MAA was placed on the floor of the nasal meatus about 1 cm behind the mucocutaneous junction, and its course was followed with a gamma camera. The nasal mucociliary clearance function was presented as the velocity (mm/minute) of nasal mucociliary transport of the Tc-99m MAA droplet. The results showed the velocity to be 4.42 +/- 2.12 mm/minute (4.61 +/- 2.37 mm/minute in the right nostril; 4.24 +/- 1.83 mm/minute in the left nostril). When the patients were grouped according to age or gender the velocity was 4.8 +/- 1.9 mm/minute (right nostril), 4.4 +/- 1.9 mm/minute (left nostril) in the older subjects (60 years and older), and 4.4 +/- 2.7 mm/minute (right nostril), 4.1 +/- 1.8 mm/minute (left nostril). In the younger subjects (59 years old and younger) (P > 0.05) the velocity was 5.0 +/- 2.7 mm/minute (right nostril), 4.3 +/- 1.8 mm/minute (left nostril) in men and 4.1 +/- 2.0 mm/minute (right nostril), 4.2 +/- 2.0 mm/minute (left nostril), in women (P > 0.05). The authors concluded that the influence of age or gender on healthy Chinese adults is not apparent. In addition, the velocity of flow in Chinese adults is slower than those in other previously reported ethnic studies.

Adult↗

PubMed1994

Lung mucociliary clearance.

The aim of this study was to establish reference values for mucociliary clearance and mucociliary clearance reserve capacity as determined by beta 2-adrenergic agonist-induced increase in mucociliary clearance. We studied 62 healthy females (n = 33) and males (n = 29). Their ages ranged evenly between 18 and 84 years. Fifty-three of the subjects were life-long non-smokers, while nine were ex-smokers. Multiple linear regression analyses showed that mucociliary clearance was significantly faster when the radioaerosol was deposited in the central airways than when it was deposited in the peripheral airways, and faster in life-long non-smokers than in ex-smokers. There was no influence of age, and no convincing association with sex. The variation was less within than between subjects. Mean mucociliary clearance reserve capacity was 21.3% (SD: 10.0%, P < 0.0001). The beta 2 agonist-induced increase in lung mucociliary clearance was significantly larger (P < 0.05) than the stimulation which has previously been reported in patients with asthma, bronchiectasis or cystic fibrosis. The signal-to-noise ratio of the mucociliary clearance reserve capacity in relation to measurement of baseline mucociliary clearance indicates that measurement of mucociliary clearance reserve capacity may be a more efficient means of distinguishing between "normal" and "abnormal" mucociliary clearance than single measurement of baseline mucociliary clearance.

Adult↗

PubMed1988

Therapeutic aspects of mucociliary clearance.

Measurements of mucociliary activity are still very approximate. It is therefore difficult to determine the particular effect of certain drugs on patients and on experimental animals. Adrenergic drugs increase ciliary efficiency; local anesthetics, barbiturates and narcotics strongly depress ciliary action. Further research is required on mucociliary clearance mechanisms.

Cilia↗

PubMed1987

Primary ciliary dyskinesia and nasal mucociliary clearance.

In this study, nasal mucociliary clearance is investigated in patients with primary ciliary dyskinesia, patients with other respiratory tract infections and healthy persons. Mucociliary clearance is established with a drop of albumen labelled with 99m-Tc. From this study it appears that measurement of mucociliary clearance in the nose can serve as a reliable screening method. If a patient with respiratory tract infections shows a normal mucociliary clearance rate there is no primary ciliary dyskinesia, and a biopsy of ciliated epithelium is not necessary. If, after repeated examinations, a normal clearance rate cannot be demonstrated, a biopsy of ciliated epithelium should be taken for studying ciliary activity and ciliary ultrastructure.

Cilia↗

PubMed1987

Mediators and mucociliary clearance in asthma.

Lung mucociliary clearance is significantly reduced in asthmatic patients compared to healthy controls even during clinical remission. Further retardation in mucous clearance occurs during sleep per se and this may be a contributing factor to nocturnal asthma. Chemical mediators of anaphylaxis appear to have various and, sometimes opposing effects on the two essential components for mucociliary clearance, namely cilia and mucus. Some mediators such as leukotrienes C4 and D4 are potent secretagogues and histamine increases the water flux into the lumen of the airways from the mucosa. Slow-reacting substance of anaphylaxis (SRS-A) reduces mucus transport whereas histamine enhances it. Ciliostimulation has been reported following allergen challenge and this contrasts with the cilioinhibitory effect of asthmatics' sputa. It appears however, that the net effect of the various chemicals of anaphylaxis is one of impairment of mucus clearance. Some pharmacological agents, used for the relief of bronchospasm and control of asthma, also stimulate mucociliary transport, a desirable additional effect.

Animals↗

PubMed1988

[Quantitative study of mucociliary clearance using static scintigraphy].

Mucociliary clearance can be evaluated by radionuclide techniques, but such approaches have been usually implemented only in research-oriented laboratories because of technical difficulties. A very practical radionuclide method is here presented which requires only three static acquisitions after the inhalation of a polydisperse radioaerosol produced by a commercial generator. Data processing is also very simple. The diagnostic performance of the method was tested on a study population of 10 healthy subjects and 10 patients with atrophic bronchitis; a highly significant difference between normal and pathological patients was found. Its simple implementation and diagnostic yield recommend this radionuclide method for the routine assessment of mucociliary clearance also in busy clinical-oriented laboratories.

Adult↗

PubMed2000

The role of rhinoscintigraphy in the evaluation of nasal mucociliary clearance function in patients with sinusitis.

Nasal mucociliary clearance is one of the homeostatic systems of the respiratory mucosa. Various rhinopathic conditions may involve alterations in nasal mucociliary clearance. The aim of this study was to assess the clinical role of rhinoscintigraphy in the evaluation of nasal mucociliary clearance function of sinusitis patients in comparison with a healthy control group. A single droplet of 99Tcm-labelled macroaggregated albumin (99Tcm-MAA) was deposited on the floor of the nasal meatus about 1 cm behind the mucocutaneous junction, and its course was followed with a gamma camera. The nasal mucociliary clearance was presented as the velocity (mm x min(-1)) of nasal mucociliary transport of the 99Tcm-MAA droplet. A significant difference in nasal mucociliary clearance was observed between the two groups, with a mean of 4.28+/-1.38 mm x min(-1) (4.3+/-1.35 mm x min(-1) in the right nostril, 4.27+/-1.42 mm x min(-1) in the left nostril) for the controls; and 1.8+/-0.64 mm x min(-1) (1.79+/-0.65 mm x min(-1) in the right nostril, 1.82+/-0.63 mm x min(-1) in the left nostril) for the patients with sinusitis. Rhinoscintigraphy is a safe, easy, quick and reliable imaging method for evaluating the ciliary activity of nasal mucosa and the nasal mucociliary clearance function in patients with sinusitis.

Adult↗