Negative impact of anesthesia with midazolam, sufentanil, and propofol used in pediatric flexible bronchoscopy on the tracheal ciliary beat frequency in guinea pigs.

There is no direct evidence for the exact cilia-inhibitory effects of opioids, which are generally used to achieve general anesthesia in combination with other anesthetic drugs. These are the reasons, why we analysed direct concentration-dependent or systemic effects of anesthetics (propofol, sufentanil, and midazolam) at a recommended doses administered individually or simultaneously on the tracheal ciliary beat frequency (CBF) in in vitro experimental conditions. Brush biopsy technique was used to remove the tracheal epithelia of guinea pigs for microscopy evaluation of ciliary beating monitored by high-speed video camera and analysed by Ciliary Analysis software. The tracheal CBF was significantly lower in the presence of sufentanil (10-8 mol/L) than in the control group; similarly for midazolam-sufentanil (10-8 - 10-5 mol/L), as well as for midazolam-propofol (10-5 and 10-3 mol/L) combinations. The fact that concurrent administration of benzodiazepine significantly increased the risk of sufentanil-induced cilia-inhibition was pharmacologically confirmed using GABAA receptor antagonist, bicuculline methiodide. The benefit of propofol on the potent cilia-inhibitory effect achieved by benzodiazepine-opioid combination was non-significant. We highlight the pharmacodynamics interaction between anesthetic drugs mediated via GABAA receptor with negative impact on the CBF in a respiratory epithelium under experimental condition rather than the effect of individual anesthetic.

Betadine has a ciliotoxic effect on ciliated human respiratory cells.

OBJECTIVE: This study investigated the effect of Betadine on ciliated human respiratory epithelial cells. METHODS: Epithelial cells from human sinonasal mucosa were cultured at the air-liquid interface. The cultures were tested with Hanks' balanced salt solution containing 10 mM HEPES (control), 100 µM ATP (positive control), 5 per cent Betadine or 10 per cent Betadine (clinical dose). Ciliary beat frequency was analysed using a high-speed camera on a computer imaging system. RESULTS: Undiluted 10 per cent Betadine (n = 6) decreased the proportion of actively beating cilia over 1 minute (p < 0.01). Ciliary beat frequency decreased from 11.15 ± 4.64 Hz to no detectable activity. The result was similar with 5 per cent Betadine (n = 7), with no significant difference compared with the 10 per cent solution findings. CONCLUSION: Betadine, at either 5 and 10 per cent, was ciliotoxic. Caution should be applied to the use of topical Betadine solution on the respiratory mucosal surface.

Dietary antioxidants prevent alcohol-induced ciliary dysfunction.

Previously we have shown that chronic alcohol intake causes alcohol-induced ciliary dysfunction (AICD), leading to non-responsive airway cilia. AICD likely occurs through the downregulation of nitric oxide (NO) and cyclic nucleotide-dependent kinases, protein kinase G (PKG) and protein kinase A (PKA). Studies by others have shown that dietary supplementation with the antioxidants N-acetylcysteine (NAC) and procysteine prevent other alcohol-induced lung complications. This led us to hypothesize that dietary supplementation with NAC or procysteine prevents AICD. To test this hypothesis, C57BL/6 mice drank an alcohol/water solution (20% w/v) ad libitum for 6 weeks and were concurrently fed dietary supplements of either NAC or procysteine. Ciliary beat frequency (CBF) was measured in mice tracheas, and PKG/PKA responsiveness to ß-agonists and NOx levels were measured from bronchoalveolar lavage (BAL) fluid. Long-term alcohol drinking reduced CBF, PKG and PKA responsiveness to ß-agonists, and lung NOx levels in BAL fluid. In contrast, alcohol-drinking mice fed NAC or procysteine sustained ciliary function and PKG and PKA responsiveness to ß-agonists. However, BAL NO levels remained low despite antioxidant supplementation. We also determined that removal of alcohol from the drinking water for as little as 1 week restored ciliary function, but not PKG and PKA responsiveness to ß-agonists. We conclude that dietary supplementation with NAC or procysteine protects against AICD. In addition, alcohol removal for 1 week restores cilia function independent of PKG and PKA activity. Our findings provide a rationale for the use of antioxidants to prevent damage to airway mucociliary functions in chronic alcohol-drinking individuals.

Effects of benzalkonium chloride and potassium sorbate on airway ciliary activity.

OBJECTIVES: Preservatives are indispensable components of aqueous multidose topical formulations. The purpose of our study was to investigate the effects of two representative preservatives, benzalkonium chloride (BKC) and potassium sorbate (PS), on rabbit tracheal ciliary beat frequency (CBF). METHODS: Rabbit tracheal ciliated cell culture was established and CBF was determined using high-speed digital imaging methods. The effects of preservatives at different concentrations on CBF were observed over a 10-min exposure period. RESULTS: BKC induced inhibition of CBF in a concentration-dependent manner. Ciliary beating was stopped by 0.01% BKC after 5 min of exposure. A low concentration of PS (0.12%) only resulted in a mild decrease in CBF during a 10-min exposure. The CBF decreased by 13.0% from baseline after 10 min. However, there was no statistically significant difference compared with the corresponding control condition. Application of 0.24, 0.48 and 0.96% of PS to rabbit tracheal cells resulted in an increase in CBF, with an increase of 105 ± 9.8, 107.6 ± 4.0, and 117.1 ± 9.5% relative to baseline CBF after 10 min of exposure, respectively. CONCLUSIONS: PS could be considered as a safer and more promising preservative than BKC for use in topical formulations.

Neutrophils potentiate platinum-mediated injury to human ciliated epithelium in vitro.

Exposure to platinum salts, such as may occur in the platinum refining industry, can be associated with the development of airway disorders such as asthma. However, there have been no studies investigating the direct effects of platinum salts on human ciliated epithelium. We have investigated the effects of platinic chloride on human ciliated epithelium, obtained by brushing the inferior nasal turbinate of healthy human volunteers. Ciliary beat frequency was measured using a phototransistor technique, and damage to the structural integrity of the epithelium was measured using a visual scoring index. Platinic chloride at concentrations between 0.25 and 25 microM caused a dose-dependent slowing of ciliary beating and damage to the structural integrity of the epithelium. These direct injurious effects were not affected by catalase, but were almost completely attenuated by preincubation of the epithelium with cysteine. The effects of platinic chloride on ciliary beating and structural integrity were enhanced by the presence of neutrophils and were partially attenuated by preincubation of the epithelial strips with catalase, suggesting that the direct effects of the metal were enhanced in this experimental system by reactive oxidants produced by activated neutrophils. This study documents that platinum salts have an injurious effect on human ciliated epithelium in vitro. If such effects also occur in vivo they may play a role, at least partly, in the pathogenesis of airway disorders that may manifest in exposed workers.

Effects of topical chlorhexidine applied to the rabbit nasal mucosa.

OBJECTIVE: To search the effects of administration of various concentrations of a wide-spectrum antimicrobial agent, chlorhexidine, to the nasal mucosa. MATERIAL AND METHODS: About 0.20, 0.12, 0.06 and 0.03% concentrations of chlorhexidine gluconate were applied to the rabbit nasal mucosa as one puff twice a day throughout 5 days. Another group, treated with serum saline to the nose, behaved as the control group. On the fifth day following drug administration, specimens were taken from nasal mucosa of the rabbits and examined under light microscope. RESULTS: As a result of comparison between drug treated group and control group, with increasing drug concentrations progressively increased neutrophil infiltration in mucosa, ciliary loss in cells, and occasional metaplasia were observed. CONCLUSION: There is a linear, positive and strong association between concentrations of chlorhexidine and its irritative effects on rabbit nasal mucosa. While 0.20 and 0.12% concentrations of chlorhexidine cause excess irritation on the nasal cavity, 0.06 and 0.03% concentrations of chlorhexidine gluconate causes lower irritation and effects on the animals which have experimentally induced rhinosinusitis must be evaluated.

Interactions of allergens and irritants in susceptible populations in producing lung dysfunction: implications for future research.

Environmental agents, when applied in combination or sequentially, can induce a wide variety of adverse health effects in humans. To determine the effects of sequential allergen challenge and acid exposure on human bronchial epithelial cell function, we subjected normal, nonallergic control and ragweed-allergic individuals to bronchoscopic segmental ragweed challenge in vivo. We harvested bronchial epithelial cells by brush biopsy both before challenge and 24 hr after challenge and exposed cells to an acid stress in vitro (pH 5 for 3 hr), followed by a 1-hr recovery period at normal pH. In normal, nonallergic subjects, segmental allergen challenge produced no effects on ciliary activity; pH 5 exposure produced reduced ciliary activity (a decrease in the percent of the initially active area), with significant recovery after cells were returned to a normal pH. Ciliary activity from allergic subjects was also inhibited by pH 5 exposure; however, activity was not recovered when cells were placed in medium of normal pH. Ciliary activity in allergics who developed a stress response postantigen challenge, as determined by an induction of the 27 kDa stress (heat shock) protein, displayed no ciliary dysfunction when exposed to a pH 5 stress. In this case, a stress sufficient to provoke a heat shock (stress) protein (HSP) response (but not one that produced more severe lung injury and did not provoke an HSP response) protected cells from a subsequent acid stress. Because of our observations and recent findings reported in the literature, we suggest that in order to define the wide variety of health effects of environmental agents, control as well as at-risk populations should be studied and the ability to define potentially beneficial as well as detrimental effects should be built into the experimental design. Inclusion of different and novel end points also should be considered.

Effects of drugs on mucus clearance.

Mucociliary clearance (MCC), the process in which airway mucus together with substances trapped within are moved out of the lungs, is an important defence mechanism of the human body. Drugs may alter this process, such that it is necessary to know the effect of the drugs on MCC. Indeed, agents stimulating MCC may be used therapeutically in respiratory medicine, especially in patients suspected of having an impairment of their mucociliary transport system. In contrast, caution should be taken with drugs depressing MCC as an undesired side-effect, independently of their therapeutic indication. Since cough clearance (CC) serves as a back-up system when MCC fails, the influence of drugs must be examined not only on MCC but also on CC. Ultimately, the clinical repercussions of alterations in mucus transport induced by drug administration must be studied. Tertiary ammonium compounds (anticholinergics), aspirin, anaesthetic agents and benzodiazepines have been shown to be capable of depressing the mucociliary transport system. Cholinergics, methylxanthines, sodium cromoglycate, hypertonic saline, saline as well as water aerosol have been shown to increase MCC. Adrenergic antagonists, guaifenesin, S-carboxymethylcysteine, sodium 2-mercapto-ethane sulphonate and frusemide have been reported not to alter the mucociliary transport significantly. Amiloride, uridine 5'-triphosphate (UTP), quaternary ammonium compounds (anticholinergics), adrenergic agonists, corticosteroids, recombinant human deoxyribonuclease (rhDNase), N-acetylcysteine, bromhexine and ambroxol have been reported either not to change or to augment MCC. Indirect data suggest that surfactant as well as antibiotics may improve the mucociliary transport system. As for the influence of drugs on CC, amiloride and rhDNase have been demonstrated to increase the effectiveness of cough. A trend towards an improved CC was noted after treatment with adrenergic agonists. The anticholinergic agent ipratropium bromide, which is a quaternary ammonium compound, has been suggested to decrease CC significantly. Bromhexine, ambroxol and neutral saline seemed not to alter CC, either positively or negatively. Finally, treatment with either amiloride, recombinant human deoxyribonuclease, bromhexine, ambroxol, N-acetylcysteine, S-carboxymethylcysteine or hypertonic saline has been suggested as a possible cause of clinical improvement in patients, such as the experience of dyspnoea, the case of expectoration or the frequency of infective exacerbations. Other agents did not show a clinical benefit.

Effects of normobaric oxygen on ciliary beat frequency of human respiratory epithelium.

Respiratory infection is a major cause of morbidity after general anaesthesia. Impairment of respiratory ciliary beat frequency (CBF) by different stress factors causes a decrease in mucus transport rate (MTR). We have tested the effect of different concentrations of oxygen on CBF of human respiratory epithelium in a prospective, randomized, in vitro study. Samples of superficial mucosa of the inferior nasal turbinates of 20 non-smoking healthy volunteers were harvested and exposed to three different oxygen environments (group I = 21% oxygen, group II = 60% oxygen and group III = 95% oxygen) for 2 h. In 50% of the samples, exposure time was prolonged. At 30, 60, 90, 120 and 240 min, light microscopic images of cilia activity were videotaped and CBF was later assessed in slow motion. Compared with baseline, group I showed no difference in CBF throughout the study. CBF was increased in group II from mean 9.7 (SD 0.4) to 11.2 (0.4) Hz (16%, P < 0.001) and in group III from 9.5 (0.6) to 12.1 (0.5) Hz (28%, P < 0.001) at 120 min. After 240 min of exposure to 95% oxygen, the CBF trend in group III was reduced to 11.8 (0.6) Hz but still remained above baseline. We conclude that oxygen appeared to have a dose- and time-dependent accelerating effect on CBF. Prolonged exposure to high oxygen concentrations reversed this trend. Direct oxygen toxicity ("oxygen stress") is a possible explanation for this effect. These changes may result in impaired MTR.

The effect of bacterial toxins on levels of intracellular adenosine nucleotides and human ciliary beat frequency.

Toxins that slow ciliary beat are virulence determinants of bacteria that infect or invade ciliated epithelial surfaces. We have previously shown that the effect of the Pseudomonas aeruginosa toxin pyocyanin on ciliary beat is associated with a fall in intracellular cAMP and ATP. We have now investigated whether reduction in intracellular adenosine nucleotides might be a common mechanism of action of other bacterial toxins which slow ciliary beat. Two other P. aeruginosa toxins, 1-hydroxyphenazine (1-HP) and rhamnolipid, and two Haemophilus influenzae fractions produced by gel filtration of broth cultures were tested. The effect on human nasal epithelium ciliary beat frequency (CBF), and intracellular cAMP and ATP were measured, and the effect of two pharmacological agents, dibutyryl cAMP and salmeterol, on these changes was assessed. 1-HP, rhamnolipid and the two H. influenzae fractions slowed CBF before there was significant release of lactate dehydrogenase from the cells. The toxins also caused a fall in intracellular cAMP and ATP. Dibutyryl cAMP and salmeterol at the concentrations used do not increase baseline CBF, but diminished the fall in CBF and intracellular adenosine nucleotides. The cAMP and ATP levels in these studies were combined with those previously obtained with pyocyanin. there was a good correlation between cAMP and ATP levels and CBF. Bacterial toxins which slow CBF may act by causing a fall in intracellular adenosine nucleotides, and agents which stimulate cAMP may prevent toxin-induced slowing of ciliary beat.

The effects of in vitro cotitine on nasal ciliary beat frequency.

Cotitine is one of the main metabolites of nicotine. It is stable and in vivo has a relatively long circulating half life. Nasal ciliated cells from non-smoking individuals were exposed in vitro to solutions of cotitine corresponding to serum levels in active and passive smokers. Ciliary beat frequency was measured by a computerized photometric technique. There was a significant drop in ciliary beat frequency compared with control ciliated cells in phosphate buffered saline. It is concluded that cotitine in active or passive smoking has a marked effect on ciliary function. It may be a factor leading to diminished mucociliary clearance and persistent middle ear effusion.

Effect of sulfur dioxide on mucociliary activity and ciliary beat frequency in guinea pig trachea.

The effects of 30 min exposure to sulfur dioxide on mucociliary activity (MCA) and ciliary beat frequency (CBF) were studied in 31 guinea pig tracheas. MCA was measured by recording the light reflected from ciliated mucous membranes using an infrared bar code reader. CBF of single ciliated cells obtained by brushing was measured with phase-contrast microscopy. Each tracheal sample was exposed to SO2 at concentrations ranging from 2.5 to 12.5 ppm, or to air for control purposes. MCA and CBF were measured before and immediately after gas exposure. A reduction in mean MCA of 63% (P = 0.0007) and statistically insignificant changes in CBF (P > 0.05) were recorded at concentrations of 2.5 ppm SO2. Higher SO2 concentrations caused a further impairment of MCA as well as a dose-dependent decrease in CBF (P = 0.002). A concentration of 12.5 ppm SO2 induced a decrease from baseline values of approximately 80% in mean MCA and of roughly 70% in mean CBF. This study demonstrates a dose-dependent SO2-induced decrease in MCA of guinea pig tracheas. The decrease in MCA was associated with an impairment of CBF only at SO2 concentrations higher than 5.0 ppm.

Nitrogen dioxide-induced eosinophilia and mucosal injury in the trachea of the guinea pig.

Nitrogen dioxide exposure-induced mucosal pathology of the guinea pig trachea was studied. Exposure to 3 or 9 ppm of nitrogen dioxide for 6 h a day, 6 times weekly for 2 weeks resulted in decreased ciliary activity as well as a dramatic eosinophil accumulation to the epithelium and submucosal layer. Especially exposure to 9 ppm of nitrogen dioxide induced epithelial injury through the activation of eosinophils accumulated in the tracheal mucosa. The epithelial damage induced by nitrogen dioxide could lead to hyperresponsiveness and prolonged allergic inflammation. Our study suggests that environmental nitrogen dioxide could contribute to the hyperresponsiveness and could most probably be involved in the development and chronicity of airway allergic disorders.

[Reactions of the ciliated epithelium of the respiratory tract to intubation anesthesia]. / Die Reaktionen des Flimmerepithels des Respirationstraktes auf eine Intubationsnarkose.

During insufflation anaesthesia the ciliary beat frequency of the ciliated cells of the trachea and the nasal cavity was assessed via vital cytological sampling from these sites before and after anaesthesia. The percentage of vital and dead ciliated cells as well as the percentage of squamous cells was counted in a chamber.-It was found that the ciliary beat frequency did not change significantly, whereas the number of vital ciliated cells in the tracheal samples was significantly reduced and the vitality of the epithelia in the nose showed a minor change. It must be presumed that the observed noxious effects on the tracheal epithelium are due to inhaled gases, since the temperature and humidity in the ventilation circuit are within a range known not to violate the ciliary epithelium. Apart from that, the intubation itself might produce reflexes in the mucosal layer.

[Effect of antitubercular preparations on the function of the ciliary epithelium of the respiratory tract mucosa]. / Vliianie protivotuberkuleznykh preparatov na funktsiiu mertsatel'nogo épiteliia slizistoi obolochki dykhatel'nykh putei.

The effect of various concentrations of streptomycin, isoniazid, rifampicin and ethambutol on the function of the siliated epithelium of the frog oral mucosa was studied (110 experiments with 50 frogs). The level of inhibition of the siliated epithelium function depended on the properties of the drugs and their concentration in solution. More pronounced inhibition was induced by 15 per cent ethambutol solution and 10 per cent isoniazid solution. The least inhibition of the siliated epithelium function was observed with the use of 6.25 per cent streptomycin solution, 5 per cent isoniazid solution, 7.5 per cent ethambutol solution and 3.75 per cent rifampicin solution.