Mucociliary wave pattern. An analysis of surface light reflections

Heating of air in the nasal airways in patients with chronic sinus disease before and after sinus surgery

The main goal of this study was to determine the influence of sinus surgery on the heating of inspired air in the nose. Intranasal temperature values of 22 patients with chronic sinus disease were measured after inspiration at different locations in the nasal cavity. Measurements were done before and 6-8 weeks after sinus surgery. The patients were compared to 22 healthy control subjects. Nasal airway temperature did not differ between the two study groups at any location in the nasal cavity. Nasal decongestion was without significant influence on temperature values in the patients and the volunteers. There was no significant difference of nasal airway temperature before and after sinus surgery. Even after sinus surgery the main area of heating of inspired air seemed to be the anterior part of the nose. Sinus surgery in patients with chronic sinus disease does not seem to influence heating of air in the nasal cavity.

Anaesthesia circuits, humidity output, and mucociliary structure and function

We compared the effects of humidity delivered by the circle system at low fresh gas flows (FGF) with a conventional two-limb and coaxial circuit on the structure and function of the tracheobronchial epithelium in dogs. Animals were anaesthetized and mechanically ventilated using an anaesthesia ventilator to maintain normocarbia. Group I (control) animals received a FGF equal to the required minute ventilation mimicking an open circuit technique. Group II and III animals had FGF set at 20% of the required minute ventilation. Group II used a two-limb circuit and Group III used a coaxial circuit. Relative humidity and temperature of inspired gases were measured at baseline and hourly afterwards. In the first experiment, biopsies of the tracheobronchial tree were obtained bronchoscopically at baseline and then hourly for six hours. Microscopic examination of these samples allowed calculation of mean ciliary length. In the second experiment, tracheal mucus flow velocity (TMFV) was measured at baseline and hourly afterward, using a cinebroncho-fibrescopic method. Delivered absolute humidity was greatest with low FGF and the coaxial circuit, followed by low FGF and a conventional circuit, and high FGF (15 +/- 1.4 vs 9 +/- 0.8 vs 5 +/- 0.4 mg H2O, P < 0.01) after two hours. Mean cilia length (micron) and TMFV (mm/min) fell during the first hour in all three groups. At hour two TMFV returned to baseline in Group III and was significantly greater than Groups I and II (0.8 +/- 0.4 vs 8.6 +/- 1.1 vs 15.4 +/- 2.1, P < 0.001). Mean ciliary length demonstrated a similar pattern with reductions from baseline in all three groups for the first two hours. Groups II and III had an increase in cilia length beginning at hour three and were both significantly greater than Group I at hours 3 through 6 (1.3 +/- 0.5 vs 3.2 +/- 1.1 vs 4.2 +/- 0.8, P < 0.001). Alterations in tracheobronchial structure and function result from exposure to dry gases and are amplified by the duration of exposure. Our findings suggest a minimum of 12 to 15 mg H2O/l is necessary to prevent these alterations. In this study, the combination of low FGF and a coaxial anaesthesia circuit reached this minimum threshold more quickly than a conventional two-limb circuit.

Recordings of mucociliary activity in vivo: benefit of fast Fourier transformation of the photoelectric signal

Investigations of mucociliary activity in vivo are based on photoelectric recordings of light reflections from the mucosa. The alterations in light intensity produced by the beating cilia are picked up by a photodetector and converted to photoelectric signals. The optimal processing of these signals is not known, but in vitro recordings have been reported to benefit from fast Fourier transformation (FFT) of the signal. The aim of the investigation was to study the effect of FFT for frequency analysis of photoelectric signals originating from an artificial light source simulating mucociliary activity or from sinus or nasal mucosa in vivo, as compared to a conventional method of calculating mucociliary wave frequency, in which each peak in the signal is interpreted as a beat (old method). In the experiments with the artificial light source, the FFT system was superior to the conventional method by a factor of 50 in detecting weak signals. By using FFT signal processing, frequency could be correctly calculated in experiments with a compound signal. In experiments in the rabbit maxillary sinus, the spontaneous variations were greater when signals were processed by FFT. The correlation between the two methods was excellent: r = .92. The increase in mucociliary activity in response to the ciliary stimulant methacholine at a dosage of 0.5 microgram/kg was greater measured with the FFT than with the old method (55.3% +/- 8.3% versus 43.0% +/- 8.2%, p < .05, N = 8), and only with the FFT system could a significant effect of a threshold dose (0.05 microgram/kg) of methacholine be detected. In the human nose, recordings from aluminum foil placed on the nasal dorsum and from the nasal septa mucosa displayed some similarities in the lower frequency spectrum (< 5 Hz) attributable to artifacts. The predominant cause of these artifacts was the pulse beat, whereas in the frequency spectrum above 5 Hz, results differed for the two sources of reflected light, the mean frequency in seven healthy volunteers being 7.8 +/- 1.6 Hz for the human nasal mucosa. It is concluded that the FFT system has greater sensitivity in detecting photoelectric signals derived from the mucociliary system, and that it is also a useful tool for analyzing the contributions of artifacts to the signal.

Stationary and nonstationary correlation-frequency analysis of heterodyne mode laser light scattering: magnitude and periodicity of canine tracheal ciliary beat frequency in vivo

Stationary and nonstationary correlation-frequency analysis of heterodyne laser light scattering were utilized to make automated, on-line, objective measurements of tracheal ciliary beat frequency (CBF) in intact, anesthetized canines. The stationary correlation-frequency analysis laser light-scattering technique was used to assess the magnitude of the CBF stimulatory responses induced by aerosolized 10(-5) M fenoterol (sympathomimetic), and 10(-8) M and 10(-6) M methacholine (parasympathomimetic) delivered to the whole lungs of eight barbiturate-anesthetized beagles. The nonstationary correlation-frequency analysis laser light-scattering technique was used to measure the effect on tracheal CBF of increasing the cytosolic calcium ion concentration with a calcium ionophore, A23187. Aerosolized A23187 was delivered to the isolated tracheal lumens of eight beagle dogs in cumulative doses ranging from 10(-9)M to 10(-6) M. Administration of the ionophore synchronized the CBF with a period of 5.3 min. Dose dependencies were observed in both the time to the peak CBF stimulation and the magnitude of the stimulatory response. The magnitude of CBF stimulation was inhibited by prior administration of aerosolized nifedipine (2 mg/ml), a voltage-operated calcium channel blocker. The A23187-induced modulation period of tracheal CBF, was unchanged by nifedipine. These are the first data to demonstrate that the magnitude and periodicity of CBF are two independent coupled processes. The cooperativity of these two processes could be determined in the effectiveness of mucociliary transport.

Degeneration of human respiratory cell ciliary beat in monolayer cell cultures

The degeneration of ciliary beat of human respiratory cells was studied in monolayer cell cultures by using a differential interference microscope equipped with a high speed video system. This method for studying ciliary beat in cell cultures on collagen-coated cover glasses is quite advantageous, because it allows for detailed study of all parts of ciliary function and not just ciliary beat frequency (CBF). In the present study both CBF and ciliary beat amplitude (CBA) were found to decrease continuously from the 1st day after plating but the wave form of ciliary beat did not change. Cultures with high cell density provided better preservation of normal ciliary beat for a longer period. In contrast, ciliary beat degenerated quickly in cultures with low cell density. CBF and CBA in cell cultures less than 5 days after plating were always high, supporting use of these cultures for studies of normal ciliary motility.

Human respiratory mucosa in a nonadhesive stationary organ culture system

Fragments of human adenoid tissue were transferred to a nonadhesive, stationary organ culture system. The culture period was 40 days. In culture, beating cilia could be observed at the surface of the fragments. Light microscopy, scanning electron microscopy, and transmission electron microscopy showed that the tissue fragments were covered by a multilayered, pseudostratified, ciliated epithelium. Beneath the epithelium was a basement membrane. At the start of the culture period, the central parts of the fragments were dominated by lymphocytes. These lymphocytes gradually disappeared and were replaced by a collagen-containing stroma with scattered fibroblasts. The tissue fragments can be used as an organ culture model for normal respiratory mucosa.

Effects of neuropeptides on mucociliary activity

The effects of four neuropeptides, vasoactive intestinal polypeptide, enkephalin, bombesin, and substance P, on mucociliary activity in the rabbit maxillary sinus were investigated in vivo. The peptides were administered via the feeding artery (arteria maxillaris), and the resulting effects were registered with a noninvasive photoelectric technique. The peptides were tested in the dose range 0.0001 to 10 micrograms/kg body weight. The following results were observed: 1) vasoactive intestinal polypeptide and enkephalin did not influence mucociliary activity; 2) bombesin had only a slight accelerating effect on the mucociliary activity at doses of 0.1 to 10 micrograms/kg; and 3) substance P markedly accelerated the mucociliary activity in a dose-dependent manner in the dose range 0.01 to 10 micrograms/kg, the maximal increase being about 50%. The effect of substance P was atropine-resistant, and probably acted directly on the mucosa.

A versatile and quantitative computer-assisted photoelectronic technique used for the analysis of ciliary beat cycles

The beat cycles of rabbit tracheal cilia in culture and Mytilus laterofrontal cirri were recorded using a phototransistor, transillumination, video, and phase-contrast microscopy. The photoelectronic signal and video image of the ciliary activity were simultaneously recorded as a composite image. The photoelectronic signal was converted into a digital signal by a data acquisition system for further computer processing. By the selection of a small detector area and accurate detector alignment, a simple, repetitive photoelectronic signal representing ciliary activity was obtained. This signal records the ciliary beat frequency and demonstrates the triphasic nature of the beat cycle. The photoelectronic signal can be precisely correlated with the ciliary activity by analysis of the composite video recordings to provide the duration of the effective, recovery, and rest phases of the beat cycle. The video-photoelectronic signal correlations were verified by high-speed cinematography. High-speed films of ciliary activity were digitized, and the image density of selected pixels was analyzed by computer with respect to time and ciliary motion. These studies indicate that duration of the phases of the beat cycle are differentially reduced with increased beat frequency; the effective phase duration was quickly reduced to a minimum. This was followed by the reduction of the duration of the recovery phase to a minimum. The rest phase continues to be reduced without reaching a minimum, over the range of beat frequencies observed. These results suggest that ciliary beat frequency may be regulated either by modifying the rates of dynein-microtubule interactions or the rate of transition from one beat phase to the next.

Studies of ciliated epithelia of the human genital tract. 3: Mucociliary wave activity in organ cultures of human Fallopian tubes challenged with Neisseria gonorrhoeae and gonococcal endotoxin

Quantative determinations of the mucociliary activity of human Fallopian tube epithelium maintained as organ cultures were performed using a light beam reflex method. In non-infected organ cultures the mucociliary wave (MCW) frequency slowly decreased during the first 54 hours of culture maintenance. In organ cultures experimentally infected with fresh isolates of Neisseria gonorrhoeae producing T1/T2 colonies the MCW frequency either decreased to subnormal values or completely ceased whereas in organ cultured infected with a laboratory-adapted gonococcal strain the MCW frequencies remained within normal range. In organ cultures exposed to gonococcal endotoxin prepared from the laboratory-adapted strain, as well as in cultures in which cell-free filtrates of medium from organ cultures infected with N. gonorrhoeae (producing T1/T2 colonies) were added to the culture medium, the ciliary activity decreased and subsequently ceased. The same phenomenon occurred when organ cultures were challenged with Escherichia coli endotoxin. The ciliostatic effect appeared before any morphological changes in the surface epithelium, including the cilia, were demonstrable by scanning electron microscopy.

The mucociliary activity of the upper respiratory tract. II. A method for in vivo studies on maxillary sinus mucosa of animals and human beings

A method for photoelectric in vivo recordings of the mucociliary activity of the mucosa of the upper respiratory tract is described and tested in model experiments. In vivo recordings from the maxillary sinus mucosa of rabbits were easy to analyse and the method is useful for further experimental research on animals. Examples of in vivo recordings from the human maxillary sinus during Caldwell-Luc operations are also presented. These results are compared with subsequent in vitro recordings of biopsy material.

Studies on ciliated epithelia of the human genital tract. II. The mucociliary wave pattern of fallopian tube epithelium

The ciliary activity of human fallopian tube epithelium was studied in vitro by using a technique which included registration of the light reflections from the mucociliary waves on the epithelial surface. In all registrations, the mucociliary waves moved toward the uterine end of the specimen. The frequencies of the reflections of the mucociliary waves ranged between 960 and 1368 cpm, with a mean of 1191 cpm (2 SD, +/- 176) and a median of 1210 cpm. Significant differences in the mucociliary wave frequencies were not observed between different parts of the fallopian tube nor between registrations performed during the follicular and luteal phases of the menstrual cycle. Scanning electron microscopy of the specimens revealed no morphologic changes of the cilia during the menstrual cycle.

The mucociliary activity of the upper respiratory tract. I. A method for use in experimental studies on human material

A method for standardized recordings of the mucociliary activity of the mucosa in the human respiratory tract is described. Nasal polyps, adenoid vegetations and biopsy material from maxillary sinuses have been used for preliminary in vitro experiments. The dependence of the mucociliary activity on oxygen supply from the surrounding air is emphasized. The influence of varying gas mixtures on the mucociliary activity can be thoroughly studied. The method is also applicable for in vivo recordings in the operating theatre during Luc Caldwell operations. A combination of in vivo and in vitro studies is under way in order to elucidate the aetiology, treatment, and prognosis of diseases of the upper respiratory tract.

Effects of ionizing radiation on the activity of the ciliated epithelium of the trachea

The immediate effect of ionizing radiation on the activity of the ciliated epithelium of the trachea has been investigated using a light reflection method. This method enables continuous registration of the mucociliary activity both during and after irradiation. A notable increase of the mucociliary activity occurred within 5 seconds after beginning of irradiation and this activity reached its maximum 10 seconds after initial exposure with a dose rate of 0.34 Gy/s (34 rad/s). The mechanism causing the phenomena observed is not clear but theoretically it might be due to ATP, the source of energy of the cilia being freed by the irradiation, possibly through disturbances of the permeability in the mitochondrion membranes.

Air humidity and mucociliary activity

The relationship between varying humidity levels in the surrounding air and the mucociliary activity in rabbit trachea has been investigated. At a relative humidity (R.H.) above 70% the risk for ciliestasis is very small in the temperature range between 34 C and 40 C. At 37 C ciliestasis is not obtained until a relative humidity (R.H.) of 50% has been reached. The critical border is reached already at 60% R.H. if the temperature is 40 C. At 37 C and a decrement from 90% to 60% R.H. the mucociliary wave frequency was reduced by 30%, but at 40 C the corresponding reduction was 60%.

Mucociliary wave pattern. A comparative analysis of extracellular and intracellular activities

Experimental in vitro studies have been made on the intracellular electrical activity and the extracellular wave movements of ciliary cells in rabbit trachea. The following results were obtained: 1. Surface light reflections from the mucous layer and from the ends of moving cilia showed about the same frequency and amplitude pattern as the intracellular action potential oscillations at 40 degrees C and 50 degrees C. At lower temperatures, however, there was a considerable discrepancy between them. 2. Surface light reflections from mucociliary wave movements had the same frequency in two areas 20 mum apart, but amplitude variations were out of phase. 3. Intracellular oscillations with a frequency of 18-21 per sec and a maximum amplitude of 1 mV have been recorded. Amplitude variations indicating rhythmical frequency variations have also been recorded. 4. The mean frequency of the intracellular action potential oscillations showed no remarkable differences at 20 degrees C, 30 degrees C, 40 degrees C and 50 degrees C.