Acute effects of sulfur dioxide exposure on the middle ear mucosa.

A variety of atmospheric pollutants are known to depress mucociliary function in the respiratory system. Since the mucociliary function in the middle ear is similar, and the middle ear may be invaded by atmospheric pollutants, we decided to investigate the possible contribution of sulfur dioxide to middle ear effusion. Guinea pigs were exposed for 24 hours to 300 ppm of sulfur dioxide or air. Immediately after exposure, ciliary activity and epithelial structure were examined close to the tympanic orifice (proximal site) and more distal to it (distal site). In the animals exposed to sulfur dioxide, no effusion was found in the tympanic cavity. Ciliary activity was reduced only in the distal site. Electron microscopy demonstrated hypersecretion in the proximal site and severe pathologic changes in the distal site. Although the normally functioning cilia in the proximal site may prevent retention of surplus secretions in the ear, sulfur dioxide may promote middle ear effusion when combined with other detrimental factors, because it stimulates mucus secretion in the proximal site and impairs ciliary function in the distal site.

Maternal antigenic stimulation actively produces suppressor activity in offspring.

Pregnant B10.A(3R) and B10.A(5R) mice were immunized with heterologous erythrocyte and protein antigens and the active immune responsiveness of their offspring was investigated by the plaque-forming cell (PFC) assay. In offspring derived from mothers which were stimulated with optimal amounts of antigens and which had fully developed antibody-forming cells, there was a clear-cut suppression in development of specific PFC over a significant period after delivery. In order to characterize the suppressor cell population, spleen cells were prepared from offspring whose mothers were immunized and thereafter treated by anti I-Jk or anti I-Jb monoclonal antibody and complement (C') followed by adoptive transfer to normal corresponding mouse strain. Only the group that received 3R spleen cells treated with anti I-Jb monoclonal antibody and C' had no suppressed PFC. To clarify the suppressor site in offspring, precursor B-cells of experimental offspring responded as hapten specific antibody forming cells by employing homologous hapten and heterologous carrier antigens. These results suggest mechanisms for suppression in offspring whose mothers were stimulated during pregnancy.

Functional and morphological pathology of the nasal mucosa after x-ray irradiation.

In our present study we examined the pathology of the nasal mucociliary system after x-ray irradiation in an animal model namely the rabbit. A reduced ciliary activity was observed immediately after the irradiation and did not show any recovery during our observation. No ciliary activity was seen in the nasal mucosa 8 weeks after the irradiation. Morphologically, hypersecretion of goblet cells was observed immediately after irradiation. Cytoplasmic vacuolation and nuclear pyknosis of ciliated cells started after irradiation, and sloughing of ciliated cells was observed for up to 3 weeks. Epithelial metaplasia started from 4 weeks, and no cilia were seen in the nasal mucosa and the surface of the epithelium was covered with flat squamous cells. Our present study shows that x-ray irradiation has serious influence on the function and structure of the nasal mucociliary system and that recovery from degeneration due to x-ray irradiation cannot be expected within several weeks.

Ciliary activity on adenoids of patients with otitis media with effusion.

Ciliary activity of the adenoidal surface in patients with otitis media with effusion (OME) was evaluated by a photoelectric method. Three groups of patients were compared: a non-OME group whose members had experienced no episode of OME; a middle ear effusion (MEE)-negative OME group whose members had an episode of recurrent OME but no MEE during the month preceding the operation; and an MEE-positive OME group whose members were experiencing an episode of recurrent OME with MEEs when tissue was taken for examination. To serve as a comparison, the ciliary activity in the central pharynx of normal guinea pigs was evaluated using the same technique. The ciliary activity in all patients was significantly lower than that in normal guinea pigs. No significant difference in ciliary activity was apparent between the non-OME group and the MEE-negative OME group. However, both were significantly higher than the ciliary activity of the MEE-positive OME patients. The following findings are drawn from our data: ciliary activity on the surface of hypertrophic adenoids is depressed, and patients with OME have reduced ciliary activity compared with those who have no otitis media or those who have otitis media without effusion.

Functional disorder of eustachian tube in experimental otitis media with effusion following inoculation of bacterial endotoxin.

A 10-micrograms/mL solution of lipopolysaccharide derived from Klebsiella pneumoniae was inoculated into the middle ears of guinea pigs. The animals were killed painlessly on the first, third, or seventh day after inoculation, and the mucosal samples from the bony portion of the eustachian tube were examined for ciliary activity and epithelial morphology. On the first and third days, when middle ear effusions were present, deterioration of ciliary activity and morphologic changes in the mucociliary system were observed. On the seventh day, when middle ear effusions were absent, the ciliary activity had recovered to normal. Our data show that endotoxin extracted from K pneumoniae can produce otitis media with effusion and that dysfunction of cilia caused by endotoxin is a factor responsible for the manifestation of otitis media.

Response of nasal ciliated cells of the guinea-pig during allergic reactions in human blood.

Nasal mucosal samples from thirty-five guinea-pigs were placed in a chamber, containing the medium RPMI 1640. Ciliary activity (beats.s-1) of the most active cell in each mucosal culture was measured using a photoelectric method. The RPMI 1640 was then replaced by 2 ml of RPMI 1640 and 1 ml of heparinized human blood from a non-allergic patient, with a ragweed-sensitive nasal allergy, or patients with D. farinae-sensitive nasal allergy: the ciliary activity of the same ciliated cell in each culture did not change significantly. We then added 1 micrograms of D. farinae extracts to evoke an in vitro allergic reaction. Ciliary excitation was induced when D. farinae extracts were added to the blood from D. farinae-sensitive subjects but not when added to blood from subjects without sensitivity to D. farinae. The peak and plateau of such an event occurred after 20-30 min. Ciliary stimulations were correlated with D. farinae-induced histamine release from whole blood. Thus, in vitro allergic reactions stimulate activity in cilia from normal nasal mucosa.

Toxicity of isopropyl alcohol exposure on the nasal mucociliary system in the guinea pig.

The toxicity of isopropyl alcohol (IPA) on the nasal mucosa in the guinea pig was experimentally studied, with special reference to the recovery process of the organ. The results showed that 400 ppm of IPA has an acute effect on the nasal mucosa and the recovery from such degeneration can occur in 2 weeks. When functional and morphological damages were induced by a higher level (5500 ppm) of IPA, it took over 2 weeks for complete recovery from such damage. The conclusion is that the present allowable level of IPA is reasonable from a viewpoint of the effect of short-term exposure to IPA on the nasal mucosa. In addition, a higher level of IPA exposure has a longer-term effect on the nasal mucociliary system in the guinea pig, and workers exposed to such a higher level of IPA should be given careful otolaryngological observation.

Reversibility of reduced ciliary activity on adenoids of patients with otitis media with effusion following culture.

We have studied the ciliary activity of the pharyngeal epithelium on adenoids obtained from patients with recurrent otitis media with effusion to assess indirectly the ciliary activity in the Eustachian tube. In conclusion, the following has been speculated from the present study: (1) middle ear effusions depress the ciliary activity; and (2) recovery of the reduced ciliary activity can be achieved in an effusion-free environment inasmuch as the ciliated cells have not undergone organic changes. Prompt elimination of the effusion, if present, is of critical importance for the recuperation of tubotympanic drainage, because a positive therapeutic effect resulting from elimination of the effusion can only be possible in early phase of the disease, before irreversible morphological lesions have occurred.

Effects of bacterial endotoxin on ciliary activity in the tubotympanum.

The discovery of endotoxin in effusion of otitis media with effusion (OME) has suggested the possibility that bacterial endotoxin may be involved in the pathogenesis and development of OME. In this study, we investigated the direct effects of lipopolysaccharide (LPS), possessing the major part of endotoxin activity, on the ciliary activity in the tubotympanum. The study shows that LPS deteriorates ciliary activity in a dose-response fashion and that even low levels can, with extended exposure, cause dysfunction of cilia. It can be postulated that endotoxin in middle ear effusions aggravates the condition of mucociliary dysfunction thus leading to chronic OME.

Acute effects of irradiation on middle ear mucosa.

Single field, fixed irradiation of bilateral tympanic cavities using 200-kV x-rays was administered to five guinea pigs. The irradiation dose was 30 Gy. They were killed immediately after irradiation, and bilateral middle ear mucosa was examined for ciliary activity and epithelial structure. Significant deterioration of the ciliary activity in the middle ear mucosa was observed, proximal as well as distal to the eustachian tube. Electron microscopy showed various changes in the irradiated middle ear mucosa. The most conspicuous findings were hyperreactivity in secretion, vacuolation of ciliated cells, and stomal edema.

An experimental study on the respiratory toxicity of isopropyl alcohol.

Guinea-pigs were exposed to 400 ppm or 5500 ppm of isopropyl alcohol (IPA) for 24 successive hours, and they were killed immediately after the exposure period. The ciliary activities of the nose and trachea were examined. In addition, the epithelium of the nose and trachea was observed by scanning and transmission electron microscopy. The present study showed that exposure to 400 or 5500 ppm of IPA vapor caused deterioration of the ciliary activity and also some pathological changes. Although our study revealed that exposure to 400 ppm of IPA vapor can affect the mucosa of the nose and trachea, the ciliary activity of the 400-ppm exposure group was not too poor and morphological changes were rather mild. Recovery from such degeneration might be rapid. Therefore, our study supports the justification of the allowable IPA level recommended by ACGIH.

Pharyngeal ciliary activity in guinea pigs with otitis media.

The function of cilia present in the tubotympanum plays an important role in the pathogenesis and chronicity of otitis media with effusion (OME). We used a photoelectric method to examine the ciliary activity in the eustachian tube, in the central pharynx, as well as the nasal cavity of normal animals and animals with otitis media. In normal animals, the ciliary activity in the nasal cavity was not different from that in the eustachian tube. In some animals with otitis media, however, there was a significant difference between the ciliary activity in the nasal cavity and that in the eustachian tube. On the other hand, no significant differences were recognized in any given group of animals examined between the level of the ciliary activity in the central pharynx and that in the eustachian tube. Our findings show that the function of the cilia present in the pharynx is a valid index of that in the eustachian tube. Our study further indicates that it may be possible to clinically assess the ciliary activity in the pharyngeal mucosa biopsied from patients with OME to determine objectively the effects of medical treatments of the disease.

Mucosal pathology of an experimental otitis media with effusion after X-ray irradiation.

Ten guinea pigs were irradiated with 30 Gy of x-radiation. Five were killed on the eighth day after irradiation, and the remainder were killed at the sixteenth day after irradiation. At the time of death, examination was made of the ciliary activity and the fine structure of the middle ear mucosa. Serous effusion was found in each tympanic cavity of all animals. It was shown also that the guinea pig, when irradiated with 30 Gy of x-radiation, exhibits pathologic abnormalities similar to those in humans with otitis media with effusion: degeneration of cilia or ciliated cells and changes in the vascular system (capillary injury and increased capillary permeability). Functional examinations showed that x-ray irradiation has delayed effects on ciliary activity, and the effects are much greater at the sixteenth day than at the eighth day. We speculate that the accumulation of effusion can be, at least partially, a consequence of ciliary dysfunction. The induction of sterile effusion by the use of x-ray irradiation provides a unique animal model for chronic otitis media with effusion of the serous type.

Acute effects of isopropyl alcohol exposure on the middle ear mucosa.

Guinea pigs were exposed to 400 ppm or 5500 ppm of isopropyl alcohol (IPA) for 24 successive hours, and then middle ear mucosal samples in both proximal and distal sites to the eustachian tube were obtained for functional and morphological examinations. The ciliary activity was examined according to the photoelectric method of Ohashi and Nakai. The morphology of the middle ear lining was examined by transmission electron microscopy. The results showed that IPA at the allowable level of 400 ppm has an acute effect on the mucociliary system of the middle ear mucosa. Recovery from damage occurs within two weeks. At higher levels of exposure to IPA (more than 10 times the allowable level) moderate deterioration of the ciliary activity and severe damage of epithelial cells were observed and recovery within two weeks was not seen. It is concluded that IPA at the allowable level of 400 ppm does not cause significant middle ear disorders, but workers exposed to higher levels of IPA should be given careful otolaryngological examinations and follow-up observations.

Effects of bacterial endotoxin on the ciliary activity in the in vitro eustachian tube.

We have used a tissue culture technique and a photoelectric method to examine the direct effect of lipopolysaccharide (LPS) on the ciliary activity present in the eustachian tube. Since LPS possesses the major part of the biological activity of endotoxin, our results show clearly that LPS deteriorates the ciliary activity in a dose-response fashion: LPS does not deteriorate the ciliary activity up to 168 h if its concentration is 1 ng/ml or less; 10 ng/ml LPS can cause deterioration of the ciliary activity with extended exposure (more than 96 h); LPS can cause dysfunction of the cilia rather quickly if the concentration is 100 ng/ml or more. Our results show that the ciliary activity in the eustachian tube under clinical conditions can be affected by endotoxin.

Nasal allergen sensitivity and mucosal IgE antibodies.

Skin tests, nasal provocation tests, nasal smear tests, and serum-radioallergosorbent tests were performed on 17 patients with perennial allergic rhinitis, who had suffered nasal congestion without receiving any antiallergic treatment. After the above tests, tissue-radioallergosorbent tests (t-RAST) were conducted to determine IgE antibody levels in inferior turbinate mucosal samples taken peroperatively. The results obtained in this study suggest that the allergen sensitivity of the nasal mucosa correlates to some extent with the mucosal IgE antibody level, and that the t-RAST can provide us with objective data about nasal allergen sensitivity.

Recovery process of tracheal mucosa of guinea pigs exposed to isopropyl alcohol.

The toxicity of isopropyl alcohol (IPA) on the tracheal mucosa was studied experimentally with special reference to the recovery process of the organ. The results showed that 400 ppm IPA has an acute effect on the mucociliary system in the tracheal mucosa, and that recovery from such degeneration can occur in 2 weeks. When functional and morphological damage was induced by a higher level (5500 ppm) of IPA, recovery did not occur in 2 weeks. The conclusion is that the present allowable level of IPA is reasonable from the viewpoint of the effects of short-term exposure to IPA on the tracheal mucosa. In addition, a higher level of IPA exposure has longer-term effects on the tracheal mucosa, and workers exposed to such a higher level of IPA vapor should be given careful otolaryngological follow-up observations.

Degeneration and regeneration of respiratory mucosa of rats after exposure to styrene.

The recovery process of pathological changes in the respiratory mucosa following exposure to styrene were experimentally studied to improve the understanding of the respiratory toxicity of styrene. Thirty male SD rats were exposed to 150 ppm or 1000 ppm of styrene for 4 h a day over 3 weeks (5 days a week). They were killed for examination at 1 day or 12 weeks after completion of the exposure sequence. Bilateral mucosal samples from the nasal septum and the trachea of the animals were examined for ciliary activity and subjected to electron microscopy. Complete functional and morphological recovery of the nasal and tracheal mucosa was observed at the 12th week post-exposure to 150 ppm of styrene. After exposure to 1000 ppm of styrene, almost normal function and morphology of the tracheal mucosa was found at the 12th week post-exposure, but the nasal mucosa continued to show decreased ciliary activity and an affected morphology.