Biomedical subjects
Publications and source records attributed to M Tos.
A review of studies of the nasal mucous elements by whole-mount methods. Goblet cell development is described till the 30th week of gestation, by which density is still very small. Density must increase towards and after birth. Some problems concerning intraepithelial, anterior nasal as well as Bowman's glands are discussed. The development of the small sero-mucous glands is described and their distribution and density discussed.
The pathology and pathogenesis of chronic secretory otitis media is described on the bais of quantitative studies of the mucosa, using whole mounts as well as serial sections of normal and biopsy specimens. The pathogenetic is divided into three stages. The initial stage, i.e. the period from the action of the aetiological factor on the middle ear mucosa till the accumulation of mucous secretion, is characterized by inflammatory processes by way of vascular proliferation and dilatation and lymphocytic infiltration. These processes trigger hyperplasia and differentiation of the epithelial cells with subsequent metaplasia of the epithelium into pseudostratified columnar ciliated epithelium with significantly increased goblet cell density and formation of mucous glands. The secretion is predominantly exudative with an admixture of mucus. The secretory stage is dominated by secretion of mucus from active mucous glands and goblet cells, the number of which has been grossly raised. The secretion accumulating in the middle ear is chiefly mucous. During the degenerative stage mucus production abates, and the middle ear returns to normal provided that irreversible adhesive changes have not occurred. The decline in mucus production is due to degeneration and inactivation of the glands combined with decreasing goblet cell density. The epithelium normalizes into cubical epithelium in one or two layers, or through metaplasia changes into secretorily inactive stratified squamous epithelium. The aetiological role of the auditory tube and the importance of tubal function is discussed. The relationship between the ability of the mucosa to produce mucus and the capability of the tube to carry it away is found to be decisive for the clinical course and the severity of the disease.
On dissected mucosa stained by the PAS-alcian blue whole-mount method the density and distribution of goblet cells in various parts of the middle ear was determined in 13 children, ranging in age from 9 days to 14 years. Goblet cells, of an irregular distribution, were found in all parts of the middle ear, but in varying density, decreasing in a given sequence from the hypotympanum anteriorly, posteriorly, promontory anteriorly and in the middle, niches of the oval and round windows, epitympanum, antrum, posterior part of the promontory, and mastoid process. During pathological actions, especially tubal occlusion, the goblet-cell density increases in all parts, simultaneously with epithelial metaplasia and new-formation of mucous glands. When the pathological stimulus ceases, the goblet-cell density again falls. In entirely normal infants and in children aged 2-4 years the goblet-cell density was found to be somewhat higher than in normal adults.
In 60 foetuses and prematures, ranging in age from the 10th to the 30th menstrual week, the entire mucous membrane from the rhinopharynx and pharynx was removed and stained in toto with PAS-alcian blue, PAS, and osmium whole-mount methods. The development, spread, and density of goblet cells as well as the differentiation of the epithelium were studied. Goblet-cell development started in the 12th week, 3-4 weeks later than the development of ciliated cells, below the tubal orifice. Thereupon, goblet cells gradually spread behind the tubal orifice, towards the roof and further on to the nose. Thus, by the 17th week goblet cells and ciliated cells are present throughout the rhinopharynx and in the upper half of the pharynx. In the lower half of the rhinopharynx and upper part of the pharynx as well as in the posterior wall, the density is fairly low during the first weeks, and later it becomes even lower. In these sites the epithelium differentiation into startified squamous and transitional epithelium. In the roof of the rhinopharynx and in the fossa of Rosenmüller the density increases steadily, and in these sites respiratory tract epithelium is present. Transformation of the epithelium, which originally contains ciliated cells and goblet cells, into startified squamous epithelium and transitional epithelium is instituted at an early stage of development and continues throughout, but possibly it is promoted postnatally by mechanical contact between the walls.
Histopathological study of the earliest stage of secretory otitis was made in a 3-month-old infant. The entire mucosa was examined by the whole-mount method, with determination of gland count and goblet-cell density, followed by assessment of serial sections. The first changes are inflammatory with lymphocytic infiltration, dilatation, and increase of blood vessels. These again induce metaplasia into pseudostratified, ciliated epithelium, increased in goblet-cell density, and formation of intraepithelial and subepithelial mucous glands. Basal cells divide and grow down into lamina propria, giving rise to a solid cylinder that gets canalized. Cells of this cylinder differentiate into ciliated and mucous cells, so that tubules acquire a lining of typical pseudostratified, ciliated, columnar epithelium. The most important processes in the early stage of secretory otitis are hyperplasia, differentiation of epithelial cells, and gland formation. When glands have completed their development, they produce mucus that accumulates in the middle ear, and the disease enters the secretory stage.
In 56 fetuses the development and spread of the nasal glands were studied by three different whole-mount methods. Development starts anteriorly in the nose and proceeds with a given regularity backward. The anterior nasal, serous glands are found only most anteriorly in the nose. They are laid down in the 11th week by the formation of long ducts that grow backward. Small seromucous glands start forming in the 13th week. They gradually spread backward in the middle and inferior meatus and hence to the medial and lateral surfaces of the inferior and middle conchae. They are present in all parts of the respiratory region except in a small area above and behind the nasal vestibule and behind the conchae, Bowman glands start developing in the 16th week, in the roof of the nose, and gradually spread down through the entire olfactory region. They are very small, tubular, and serous. Bythe 23rd week gland formation has been completed.
A defective stapedial arch was found among 690 operated patients in 46 ears (6-7 per cent). Most often it was the stapedial head or anterior limb which was absent. The problems and results of ossiculoplasty on a defective stapes are analyzed. Classical interposition of the incudal body on top of a defective stapes did not afford satisfactory results, as the incus had to be placed asymmetrically on top of the stapedial remnant, with a risk of fixation and tilting of the graft. Better results were obtained by interposition of the short process of the incus on the footplate in a way which gives the incus contact also with the remaining parts of the stapedial arch. If the neck and head of the stapes are absent, it is suggested that the ossicles be shaped in relation to the defect in such a way that contact between the stapedial remnant and the malleus will be stable and the risk of secondary fixation minimal. If there are partial defects of the stapedial limbs the columella should be in contact with the footplate as well as with the remaining parts of the limbs.
The methods, results, and indications for operation on only hearing ears are discussed on the basis of 13 patients operated upon for chronic otitis media and its sequelae. Although good results were obtained, with an air-bone gas closure within 15 dB. in 77 per cent, this should not serve as propaganda for the general use of surgery on only hearing ears. On the other hand, they show that surgery on only hearing ears should not be rejected a priori and that on certain indications and under c ertain circumstanc es it may be carried out with minimal risk of aggravating the hearing loss. In most of the patients the indication for surgery was a progressing cholesteatoma, in some cases the sequelae of otitis, either in the form of myringoplasty or type II tympanoplasty, and one patient had the operation on a vital indication. To avoid postoperative exacerbation of the hearing, the patients must be strictly selected, the ears have to be pretreated conservatively, the Eustachian tube must be passable, the operation must be carried out by the most experienced otosurgeon, and thoroughly tested, very gentle operative methods must be used.
A fistula on the lateral semicircular canal was found in 14 (4.8%) ears with cholesteatoma. In 11 patients with preserved inner-ear function the cholesteatoma membrane was removed, the fistula was solidly closed with fascia, bone, and again fascia. The cavity was obliterated, the meatal wall reconstructed, and tympanoplasty performed in the same stage. Ten patients obtained a hearing gain, an average of 16.8 dB, while one developed anacusis. The results show that the cholesteatoma matrix can be removed from most fistulae. In the case of large fistulae, in which the cholesteatoma matrix is adhering to or invading the fistula, there is a great risk of perceptive hearing loss. By closing the fistula with fascia and bone and using a closed technique a lasting hearing gain may be achieved.
In 30 ears from 24 children with chronic secretory otitis the density of goblet cells and of glands was determined on biopsies from the anterior part of the promontory. The goblet-cell and gland density proved to be highly increased in all cases, with marked individual variations. The median density of goblet cells was 142 cells/field, corresponding to 8,000 cells/mm-2. This substantiates the fact that in chronic secretory otitis the mucous secretion is a product of goblet cells and mucous glands and confirms the secretory pathogenesis of the disease.
On ten foetuses, ranging in age from the 13th to the 30th menstrual week, the entire nasal mucosa was removed, stained by the PAS-alcian blue whole-mount method, and the density of goblet cells in the various parts of the nose was determined quantitatively. For each locality there was a characteristic density curve, consisting of an increase, a peak, and a decrease. The following factors, influencing changes in density, are discussed: (1) Spread of goblet cells causing the density to increase first in the anterior part of the nose, where goblet cells appear first. (2) Growth of the mucosa whose area increases constantly and regularly. (3) Intensity of goblet-cell newformation which is high during the first weeks, but is then followed by a period of decrease. (4) Lifetime of the goblet cells which is presumably longer in the respiratory tract than in the intestinal epithelium.
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