Beat Frequency Of Cilia Research Articles

Beat frequency of cilia in the branchial basket of the ascidian Ciona intestinalis in relation to temperature and algal cell concentration

To elucidate the effects of temperature and algal cell concentration on pumping of water in the ascidian Ciona intestinalis a number of different experiments were performed. Beat frequency of the lateral cilia in the openings of the branchial sac was measured in intact specimens using a microprojection objective and a monochrome CCD video camera. At constant low algal cell concentration, beat frequencies increased linearly with temperature from 4.0 Hz (±0.5) at 7.4 °C to 13.6 Hz (±1.6) at 20.1 °C. At a constant temperature of 15 °C, beat frequency decreased with increasing algal cell concentration from approximately 3000 to >10 000 Rhodomonas sp. cells ml−1. The decrease was observed both in experiments where the ascidians had been acclimated to a fixed algal cell concentration and in experiments with changing concentrations. Effect of algal cell concentration on squirting/siphon closure and flow velocity in the exhalent siphon was measured using a thermistor. At low algal cell concentrations, flow velocity in the exhalent siphon was stable, apart from a few short squirts. At very high algal cell concentrations, the flow velocity was reduced and much less stable, with prolonged squirting. The effect of gut content on filtration was studied in experiments with specimens acclimated to high algal cell concentrations. Results showed a close relation between gut clearance and filtration rate. From the experimental results and a qualitative analysis of the Ciona-pump it was concluded that the ciliary beat frequency is proportional to the water flow through the sea squirt and that changes in pumping caused by temperature or algal cell concentration are under nervous control or governed by enzyme kinetics, rather than being a result of physico-mechanical properties, i.e. pump efficiency versus flow resistance, of the ascidian pump.

An investigation into the effects of midazolam and propofol on human respiratory cilia beat frequency in vitro.

Patients in intensive care are known to be prone to both upper and lower respiratory tract infection. Respiratory mucus forms a barrier to infection. Mucus transport rate (MTR) depends upon both the physical properties of mucus and the action of respiratory cilia. Patients undergoing anaesthesia are known to have a reduced MTR that may be related to a depressant effect on cilia beat frequency (CBF) by anaesthetic drugs. The aim of this study was to investigate the effects of two commonly used intensive care sedative agents, midazolam and propofol, on CBF using human nasal turbinate explants in vitro. We exposed ciliated tissue from human nasal turbinate explants to midazolam and propofol in supraclinical concentrations (20 microM midazolam and 70 microM propofol) in a controlled and blinded manner for 90 min and measured CBF by the transmitted light technique. After 90 min, mean (SEM) CBF in the group exposed to midazolam and its control group were 13.0 (0.2) Hz and 12.9 (0.3) Hz, respectively. Mean (SEM) CBF in the group exposed to propofol was 13.6 (0.4) Hz and in the control group the value was 12.0 (0.6) Hz. There was no significant change in CBF (midazolam: p = 0.21, propofol: p = 0.31, MANOVA for repeated measures). We have found no effect of midazolam or propofol in supra-clinical concentrations upon CBF in human turbinate explants after a 90-min exposure. This contrasts with previous work that has shown a depressant effect of inhalational anaesthetic agents on CBF.

The effect of chronic nasal application of chitosan solutions on cilia beat frequency in guinea pigs

The cilia beat frequency (CBF) was evaluated in guinea pigs after daily nasal administration of various chitosan solutions for 28 days. The chitosans tested were of various molecular weights and degree of deacetylation. The effect of the chitosans on the CBF was measured on the excised nasal tissue and compared to the effect of sodium taurodihydrofusidate and cocaine by means of a microscope connected to a video camera mounted on the phototube and a data acquisition unit. The results showed that none of the chitosans tested has any effect on the CBF as compared to the controls.

The role of Ca2+ in deflection-induced excitation of motile, mechanoresponsive balancer cilia in the ctenophore statocyst.

Motile, mechanoresponsive cilia (balancers) in ctenophore statocysts, like vertebrate hair cells, are excited or inhibited depending upon the direction in which they are deflected. Balancers, however, may become either excited (beat rapidly) or inhibited (beat slowly) by deflection in the same direction, depending on the sign of ctenophore geotaxis (positive or negative). The beat frequency of many cilia is controlled by concentrations of Ca2+, membrane potential and neural input. How these factors affect deflection-induced ciliary beating in balancers was investigated. Deflection-induced excitation of balancers in whole Mnemiopsis leidyi larvae and dissected adult (Mnemiopsis leidyi, Pleurobrachia pileus) statocysts was reversibly inhibited by the Ca2+ channel inhibitors Co2+, Mg2+, Ni2+, and Mn2+. Deflection-induced excitation in balancers of isolated adult M. leidyi balancer groups was also inhibited by Co2+ or by Ca(2+)-free medium. Isolated balancer group cilia, like balancer cilia of intact ctenophores, exhibited responses to either sign of geotaxis and graded responses to deflection. Isolated balancers that were chemically depolarized in high-[K+], Ca(2+)-free medium were excited by local application of Ca2+ onto the ciliary bases, but not onto the cell bases or the ciliary tips. It is proposed that deflection-induced excitation of balancers is due to influx of Ca2+ through stretch- and voltage-activated channel activity. The sign of geotaxis of whole larvae and dissected adult statocysts was switched by electrical stimulation. Thus, neural input may participate in reversing the directional sensitivity of balancer cells.

Role of macrophage-stimulating protein and its receptor, RON tyrosine kinase, in ciliary motility.

Macrophage-stimulating protein (MSP) is an 80-kD serum protein with homology to hepatocyte growth factor (HGF). Its receptor, RON tyrosine kinase, is a new member of the HGF receptor family. The MSP-RON signaling pathway has been implicated in the functional regulation of mononuclear phagocytes. However, the function of this pathway in other types of cells has not been elucidated. Here we show that in contrast to the HGF receptor, which was expressed at the basolateral surface, RON was localized at the apical surface of ciliated epithelia in the airways and oviduct. In addition, MSP was found in the bronchoalveolar space at biologically significant concentrations. MSP bound to RON on normal human bronchial epithelial cells with a high affinity (Kd = 0.5 nM) and induced autophosphorylation of RON. Activation of RON by MSP led to a significant increase in ciliary beat frequency of human nasal cilia. These findings indicate that the ciliated epithelium of the mucociliary transport apparatus is a novel target of MSP. Ciliary motility is critical for mucociliary transport. Our findings suggest that the MSP-RON signaling pathway is a novel regulatory system of mucociliary function and might be involved in the host defense and fertilization.

Acute Effects of Uridine 5′-Triphosphate on Mucociliary Clearance in Isolated Frog Palate

Mucociliary velocity (MCV), transepithelial potential difference (PD), cilia beat frequency (CBF), mucus collection rate, rheology, and chloride concentration [Cl−] were analyzed in an in vitro study using the freshly isolated frog palate exposed to an aerosol of modified Ringer's injection, followed by uridine 5′-triphosphate (UTP) 10−4 mol/L either alone or immediately preceded by aerosolization of 5 × 10−4 mol/L 4,4′-diisothiocyano-2,2′ stilbenedisulfonate (DIDS), a chloride channel blocker. UTP increased PD and decreased MCV with a positive relationship between the two. UTP promoted the appearance of copious quantities of secretion and increased the collection rate; the computed mucus depth increased by more than sixfold. There was a significant increase in both [Cl−] and wet weight. The increase in PD and chloride secretion led to enhanced transepithelial fluid transport and a decrease in MCV. Rheology and CBF were not affected by UTP, indicating that the main effect was on the interaction between the mucus and the cilia. All the positive effects were blockable by DIDS. The significant increase in chloride content and mucus volume and their relationship with percentage of solids indicate that UTP is an effective stimulant of mucus secretion, which is attributable to secretion of both chloride and macromolecules. The results support the presence of Ca2+-dependent chloride channels on the epithelial surface of the frog palate.

Calcitonin gene-related peptide in vitro stimulation of ciliary beat in human upper respiratory cilia.

Calcitonin gene-related peptide (CGRP) is one of the neuropeptides that is released in the human nasal mucosa after trigeminal nerve stimulation. We investigated the in vitro effect of CGRP on the ciliary beat frequency (CBF) of human upper respiratory cilia. Ciliated epithelium of freshly removed adenoidal tissues was used in all experiments. CBF was measured using a computerized photo-electric method. The results showed that CGRP exerted a significant dose-dependent stimulation on CBF in concentrations of 10(-9)-10(-6) M (n = 10), with a maximum of 23%. Our findings indicate that CGRP in vivo may help to protect the airway epithelium by directly stimulating ciliary beat.

Impaired Nasal Mucociliary Clearance in Long-Distance Runners

For years physicians have observed a high incidence of upper respiratory tract infections (URTI) after strenuous exercise. Mucosal surfaces represent a first-line-of-defense against infections, and pollutants or organisms entrapped in respiratory secretions are cleared by mucociliary transport. Little is known about this mechanism during exercise. The purpose of this study was to examine the nasal mucociliary clearance (MMCC) in amateur runners competing in a marathon race. Twelve amateur runners entered in an inner-city marathon race and 10 healthy sedentary subjects participated in the study. On the day of the race the outside temperature was 3 degrees C. Nasal mucociliary transit time (NMTT) was measured daily for 1 week before and 1 week after the race by the saccharin sodium/indigo carmine method. Nasal tissue biopsies were taken, and cilia beat frequency (CBF) was measured as viability and function of ciliated epithelial cells were determined. NMTT was significantly prolonged after the race (17.1 +/- 1.2 min vs 8.9 +/- 0.9 min; athletes vs control group; mean +/- SEM) and returned to baseline over several days. CBF was significantly reduced only in the first 24 hours after the race (7.31 +/- 0.65 Hz for athletes vs 9.94 +/- 0.45 Hz, controls. After the race, athletes showed a higher percentage of ciliated cells with immotile cilia (37.1 +/- 1.3% vs 27.8 +/- 1.1%, athletes vs controls) or dead ciliated cells (7.3 +/- 0.9% vs 4.1 +/- 0.8%). The findings suggest impairment of NMCC up to several days after strenuous exercise, which might be partially caused by abnormally functioning ciliated cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Ciliary defects in healthy subjects, bronchiectasis, and primary ciliary dyskinesia.

To develop criteria to aid in the diagnosis of primary ciliary dyskinesia (PCD) we analyzed quantitatively the incidence and the range of ciliary ultrastructural abnormalities in healthy subjects and in patients with respiratory tract disease. The beat frequency and ultrastructure of nasal respiratory tract cilia, including ciliary orientation, were measured in 62 healthy subjects (31 nonsmokers, 20 exsmokers, and 11 smokers), ranging in age from 1 to 76 yr, and in 51 patients with respiratory tract disease. In healthy subjects, ciliary beat frequency (CBF) ranged between 9.6 and 15.3 Hz, the incidence of microtubule defects varied between 0 to 9%, the mean number of inner dynein arms per cilium ranged from 3.0 to 7.1, and the mean number of outer dynein arms per cilium ranged from 7.4 to 9.0. The deviation of cilia in healthy subjects varied between 8 and 29 degrees. By comparing the data for ciliary defects in healthy subjects with the data obtained from patients with respiratory disease, we identified two patient groups: patients with PCD (n = 31) and patients with respiratory tract disease not due to PCD. For comparison with the PCD patients, a group of 20 patients with bronchiectasis was selected and analyzed. Patients with PCD had significantly lower CBF (p < 0.001), significantly higher incidences of peripheral and central tubule defects (p < 0.01), and greater ciliary disorientation (p < 0.005). There was a strong correlation between CBF and the number of outer dynein arm numbers, but not with inner dynein arm numbers, suggesting that inner and outer dynein arms may play different functional roles in producing ciliary motility.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of prostaglandins D2 and E2 on ciliary beat frequency of human upper respiratory cilia in vitro.

Diminished mucociliary transport can occur in a type-I (Ig-E mediated) allergic reaction. We determined the effects of the allergy mediators prostaglandin D2 (PGD2) and prostaglandin E2 (PGE2) on the ciliary beat frequency (CBF) of human upper respiratory cilia in vitro. Human adenoid tissue was used as the source for ciliated epithelium. CBF was measured by a computerized photo-electric method. PGD2 (10(-8)-10(-5) M, n = 7) showed no statistically significant effect on CBF. PGE2 (10(-9)-10(-6) M, n = 10) caused a significant dose-dependent stimulation, with a maximum of 37% (ANOVA, p < 0.001). Thus prostaglandins D2 and E2 do not exert a direct negative influence on ciliary activity, which could account for a decrease in mucociliary transport. The stimulating effect of PGE2 may be relevant in promoting mucociliary clearance in vivo.

Brain and respiratory cilia: the effect of temperature.

We have used a modified photodiode method to measure ciliary beat frequency of human neonatal cilia, and have developed techniques to allow similar measurements of rat brain cilial function. The effect of temperature change, within the physiological range, on neonatal human respiratory cilia and neonatal rat brain cilia was studied. The mean (SD) ciliary beat frequency of neonatal respiratory cilia at body temperature was 14 (1.1) Hz and that of rat brain cilia 18.9 (1.3) Hz. Respiratory cilial beat frequency decreased by 9.1% and brain cilia by 13% on cooling to 32 degrees C compared to normal body temperature. Beat frequency increased by 8.5% in respiratory samples and by 12% in brain samples on warming to 40 degrees C compared to the frequency at normal body temperature. The Q10 of human neonatal respiratory cilia was 1.2 and that of rat brain cilia 1.3.

Histamine and leukotriene C4 effects on in vitro ciliary beat frequency of human upper respiratory cilia.

Decreased mucociliary transport can occur in patients with type I (IgE-mediated) allergic rhinitis or allergic asthma. This study investigated if the allergic mediators histamine and leukotriene C4 (LTC4) could interfere with ciliary beat frequency (CBF) of in vitro human upper respiratory cilia and eventually result in decreased mucociliary transport. Ciliated epithelium of human adenoid tissue was used in the experiments and CBF was determined using a computer-assisted photoelectric method. Histamine in concentrations of 10(-6) - 10(-3) M (n = 12) and LTC4 as 10(-9) - 10(-6) M solutions (n = 10) showed no statistically significant dose-dependent effect on CBF in vitro.

Polymorphonuclear leukocyte-generated oxygen metabolites decrease beat frequency of human respiratory cilia.

We investigated the effect of polymorphonuclear leukocyte (PMN)-generated oxygen metabolites on the ciliary beat frequency. PMNs were incubated with human respiratory cilia obtained by nasal brushing. The oxidative metabolism was stimulated by opsonized zymosan, and ciliary beat frequency was evaluated before and after activation of PMNs. Ciliary beat frequency was studied using video microscopy. Our results demonstrate a significant decrease in ciliary beat frequency after activation of PMNs. This effect was reduced by catalase. These data suggest that the PMN-generated oxygen metabolites, particularly H2O2, decrease beat frequency of human respiratory cilia.

Effects of insulin and nasal absorption enhancers on ciliary activity

The potential ciliotoxicities of insulin and of the protein absorption enhancers, aprotinin and sodium cholate, were investigated by monitoring the decay in beat frequency of rat cilia exposed to them. Comparison of the area under the ciliary beat frequency decay curves indicates that insulin is relatively non-ciliotoxic over the time exposures studied. Aprotinin, a peptidase inhibitor and sodium cholate, a surface active bile salt, were both highly ciliotoxic. When admixed those two absorption enhancers showed additive rather than synergistic ciliotoxicity. The data suggest that those compounds exert a direct toxic effect on the cilial membranes. Use of those additives in intranasal formulations is therefore contraindicated.

Ciliotoxicity of intranasal formulations: Menthol enantiomers

AbstractIt is shown, using in vitro measurements of beat frequency of rat tracheal cilia, that (+)‐(1S, 2R, 5S)‐menthol and (−)−(1R, 2S, 5R)−menthol have equipotent ciliotoxicities despite the fact that inhalation of menthol vapours from the crystals of the pure enantiomers show clearly that the (−)−(1R, 2S, 5R)‐menthol produces a more potent cooling sensation. Differential scanning calorimetry demonstrates the formation of a racemic compound when equimolar amounts of the two enantiomers are admixed. © 1993 Wiley‐Liss, Inc.

Mechanism of hydrogen peroxide-induced inhibition of sheep airway cilia.

To study the effect of the inflammatory mediator hydrogen peroxide (H2O2) on airway ciliary activity, we measured ciliary beat frequency (CBF) in cultured tracheal explants from sheep. Addition of H2O2 (10(-8) to 10(-4) M) produced a concentration-dependent mean (+/- SEM) decrease in CBF between 11.1 +/- 0.4% (P less than 0.01) and 100 +/- 0% (P less than 0.001); at each concentration, the maximal effect was reached by 20 to 25 min. Between 10(-8) and 10(-6) M H2O2, the decrease in CBF was reversible, lactate dehydrogenase (LDH) release was not significantly increased, and major morphologic lesions were not seen. At higher concentrations of H2O2, incomplete recovery of CBF (10(-5) M) or irreversible ciliostasis (10(-4) M) developed, and a significant increase in LDH and morphologic lesions were present. Catalase (2,000 U/ml) and H-7 (10(-5) M), a protein kinase inhibitor, abolished cilioinhibition produced by H2O2 at 10(-6) M and lower concentrations but not at 10(-5) M and higher concentrations. Phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator, caused a dose-dependent (10(-11) to 10(-5) M), reversible decrease in CBF; this effect was abolished by H-7. We suggest that at nonlethal concentrations, H2O2 inhibits the beat frequency of airway epithelial cilia reversibly, through the activation of second messengers, including protein kinase C. This mechanism might contribute to the previously demonstrated impairment of mucociliary clearance in airway inflammation.

Beat frequency of lateral Cilia in intact filter feeding bivalves: Effect of temperature

Abstract The beat frequency of the lateral cilia was measured stroboscopically in young transparent specimens of the bivalves Abra nitida, Abra alba, Spisula subtruncata, Corbula gibba, Mytilus edulis and Cultellus pellucidus. The beat frequency was uniform among the species, amounting to about 10 Hz at 14°C, which was about the temperature they were adapted to in nature. Frequencies were higher at 20–21°C, corresponding to a Q10 value of 2 to 3. Beating stopped abruptly at valve closure. Abrupt stoppage of beating also occurred at closure of the aperture of the exhalant siphon in the absence of valve closure. At relaxation of the sphincter the cilia resumed beating equally abruptly.

Dissimilar Expression of Axonemal Anomalies in Respiratory Cilia and Sperm Flagella in Infertile Men

Infertility by sperm immotility may be a consequence of axonemal defects, and it is sometimes associated with respiratory disease as in the primary ciliary dyskinesia. The purpose of this study was to investigate the respiratory epithelium of 13 infertile patients with flagellar ultrastructural anomalies whether they suffered or not from respiratory disease. Only one patient had severe respiratory disease. The beat frequency of nasal cilia (9 to 13 Hz) was considered normal in 11 of the 13 patients. All the cilia were found abnormal in one patient. In 12 of 13 infertile men (92.3%), significant ultrastructural cilia anomalies were found (greater than 7%) even though the men did not suffer from any respiratory disease. Axonemal anomalies were found at both levels either of the same type (four cases) or only partially similar (two cases) or totally different (six cases). The most frequently abnormal substructure of cilia was the central complex (10 of 12) even in cases exhibiting a different abnormal pattern at the flagellar level. Findings are discussed according to those found in animal mutants. Our results suggest that ciliary and flagellar axonemes should be controlled both by common and by different groups of genes.

Regulation of ciliary activity in the mammalian respiratory tract

A computer-assisted transillumination, photoelectronic technique has been used to measure the beat frequency of cilia of rabbit tracheal cells grown in culture. When ciliated cells are mechanically stimulated with a microprobe the cells respond rapidly by increasing the beat frequency of their cilia. This mechanosensitive response is not limited to the stimulated cell, but is communicated in all directions to neighboring cells. To characterize the progression of this communicated response we used an automated computer-assisted imaging system to examine high-speed films of responding cells. The time it takes for the response to be transmitted between cells is slow (1-3 sec) with each cell responding after a lag-time that is proportional to the distance of the cell from the stimulated cell. We have confirmed that gap junctions are present between cells and that adjacent or non-adjacent ciliated, as well as non-ciliated, cells are electrically coupled. To correlate the mechanosensitive response with intracellular calcium fluxes we have used fura-2, a calcium-specific fluorescent dye, and digital video microscopy. Mechanical stimulation of the cultured ciliated cells, in the presence of extracellular calcium, resulted in an initial increase in intracellular calcium, which was communicated to neighboring cells. Without extracellular calcium, mechanosensitivity of cultured cells was lost and a small decrease in intracellular calcium was observed in the stimulated cell. However, neighboring cells still displayed an increase in intracellular calcium. The time course and general pattern of calcium increase in adjacent cells was similar to the responses in ciliary activity produced by mechanical stimulation. Ciliary beat frequency is also elevated by beta-adrenergic drugs independently of mechanosensitivity. These responses are important because they could provide a dual regulatory mechanism for the control of mucus transport. Adrenergic agonists could provide non-specific control by increasing ciliary activity throughout the airways while mechanosensitivity could provide local control by increasing activity in those regions of heavy mucus load.

Increased Ciliary Beating Frequency of Nasal Mucosa following Immunotherapy for Allergy

The present study was designed to elucidate the effect of immunotherapy on the beating frequency of nasal cilia in patients with nasal allergy. Of 40 patients with nasal allergy due to Dermatophagoides farinae, 20 were treated with immunotherapy by the use of D farinae extracts, and 20 control patients were treated with antihistamine tablets. Mucosal pieces were taken from the right inferior turbinate before and 1 year after the initiation of treatment, and the ciliary beating frequency (CBF) was examined by a photoelectric method. The use of antihistamine tablets did not increase CBF even when it relieved the nasal symptoms. Immunotherapy, on the other hand, increased CBF in 66.7% of patients when it alleviated their nasal symptoms. The CBF before immunotherapy of patients who showed an increase CBF after treatment was statistically higher than that of patients who did not.