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Biomedical subjects

M Tos

Publications and source records attributed to M Tos.

At least 415 records · Page 23Linked to original sources
PubMedDate not supplied

Middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation.

Changes in middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation were studied in 47 patients who had been intubated, for various reasons, during 1-24 days. All the patients had a negative middle ear pressure; in 84% of the ears the pressure was -200 mm of water or less. In most ears the pressure fell rapidly after the intubation, being most negative before extubation and during the first 2 days after. In all patients who could be followed the pressure returned to normal. The normalization was slow, depending upon the duration in intubation. Possible causes, such as abolished ventilation of the rhinopharynx, insufficient swallowing, mechanical occlusion of the tubal orifice, and the influence of anaesthetic gases are discussed. During the period after extubation the most probable cause is irritative and inflammatory reaction of the mucosa, leading to internal tubal occlusion.

Adult↗
PubMedDate not supplied

Nasal glands in nasal allergy.

The entire nasal mucosa from a patient with nasal allergy and hay fever was studied by the whole mount method, and the density of submucous glands was determined. Their density was essentially greater than in normal noses in all parts of the nose, especially on the conchae. This finding indicates that new-abnormal-glands form in the course of the disease, glands which also differ morphologically from the normally occurring glands. As this greatly increases the secretory capacity of the mucous membrane, there is a patho-anatomical basis for assuming that the nasal secretion in allergy is formed exclusively by the existing glands. Other sources of nasal secretion, such as exudation and transudation under normal conditions and in allergy, as well as the mode and causes of gland formation, are discussed.

Adolescent↗
PubMedDate not supplied

Experimental surgery on the nose. I. Airflow and goblet-cell density.

In rabbits the nasal vestibule was surgically occluded on one side. The rabbits were observed for varying periods, maximum 90 days. The mucosa of the septum was removed from both sides, stained by the PAS-alcian blue whole-mount method, and the goblet cells were counted. The difference in goblet-cell density between the occluded and open side of the nose was less than expected according to previous reports. A completely abolished air flow for 3 months caused only some increase in density. During the first 16 days there was an increase in density on the occluded as well as on the open side of the nose. This can hardly have been due to altered airflow, but must be attributed to an irritative action by the operation upon the nasal mucosa.

Airway Obstruction↗
PubMedDate not supplied

Experimental surgery on the nose. Changes of the epithelium in the vestibular region at altered airflow.

In 20 rabbits one nostril was closed surgically and the nasal mucosa lying anteriorly in the vestibule was studied 4--90 days postoperatively. On the occluded side, without air-flow, the epithelium--which at this site is normally thickened due to hyperplasia of basal cells--gradually returned to a normal thinner, regular epithelium with increased number of goblet cells. On the patent side, where the airflow was doubled, the cilia were damaged. As early as the 4th day, a process of repair had been initiated, with hyperplasia of basal cells and differentiation of these cells into ciliated and goblet cells. As a result of continued trauma, similar processes continued, but there were no signs of a permanent transformation of the epithelium into squamous epithelium, not even on the 90th day.

Animals↗
PubMedDate not supplied

Attic retractions following secretory otitis.

At re-examination of 527 ears with secretory otitis 3 to 8 years after tubulation otomicroscopy and tympanometry revealed different types of retraction of Shrapnell's membrane in 34%, of these 4.2% had pronounced retraction with resorption of the osseous annulus and 0.2% had atticus cholesteatoma. There was a close correlation between the frequency and severity of retraction on the one hand and the age of the patient at reexamination, the tympanometric conditions, and the pathology of pars tensa on the other. The continued progression is further promoted by a lack of natural cleansing of the retraction. As the frequency of secretory otitis is very high in children the 4.2% of pronounced retractions constitute a sufficient quantitative basis for a direct progression to atticus cholesteatoma.

Acoustic Impedance Tests↗
PubMedDate not supplied

Experimental tubal obstruction. Changes in middle ear mucosa elucidated by quantitative histology.

Two and 4 weeks after experimental tubal occlusion in germ-free rats the goblet cell density in the middle ear was increased, compared with the normal contralateral side, indicating that transformation of epithelial cells to secretory cells can occur without infection. Other histopathological changes such as vasodilatation, oedema, round cell infiltration, fluid uptake of epithelial cells (which were thereby distended), hyperplasia of the epithelial cells, formation of intra-epithelial glands and some few subepithelial glands, are described. The finding may indicate that negative middle ear pressure and fluid uptake into the cells damage the epithelium, and the succeeding processes may be regarded as reparative processes following the epithelial damage.

Animals↗
PubMedDate not supplied

Middle ear pressure during brief pathological conditions of the nose and throat.

Middle ear ventilation was investigated by repeated tympanometry in different groups of patients with impaired air current in the upper airways. Among patients with total blocking of the nose by bilateral anterior packing, 46% had a negative pressure of -100 mm H2O or less, which quickly returned to normal after removal of the packing. Unilateral anterior packing produced no significant changes in middle ear ventilation. Unilateral posterior packing produced changes in 50% of ears, tonsillectomy in 60% of ears, amounting to a negative pressure of -100 mm H2O or less. Patients with infectious mononucleosis showed the poorest middle ear ventilation, 45% having pressure between -100 and -199, 45% between -200 and -350 mm H2O. Normalization of the pressure was very slow, but occurred in all cases after 2-4 weeks. The different pathogenetic possibilities, viz. direct occlusion of the tubal orifice, inflammatory mucosal reaction, insufficient swallowing, insufficient air current through the rhinopharynx, are discussed.

Acoustic Impedance Tests↗
PubMedDate not supplied

Spontaneous improvement of secretory otitis. A long-term study.

Six repetitive tympanometric screenings were performed on 184 2-year-old, otherwise healthy children (368 ears) between November 1977 and February 1980. Between each examination half of the ears changed tympanogram type; during summer and spring more ears improved than deteriorated and during winter and autumn the reverse took place. Type B representing flat curve without impedance minimum improved at each examination in more than half of the ears, but a large number of "new' ears received a type B tympanogram. In all, 39% of all ears had type B at one examination at least, 7% had type B at two examinations, 4% at three, 4% at four, and 2% at five examinations; only one ear (0.3%) had a type B tympanogram at all six examinations. The investigation revealed a very high total frequency and spontaneous improvement of secretory otitis. In this period of 2 and a half years, 70% of ears had types B or C2 at one examination at least. On account of the pronounced spontaneous improvement, the results of any method of treatment-when the indications are wide-will be good, although even studies on controlled materials, comparing two methods of treatment, are encumbered with considerable uncertainties.

Acoustic Impedance Tests↗
PubMedDate not supplied

Patient-specific cell-mediated immunity against human acoustic neuroma extract.

Lymphocytes from 8 patients with acoustic neuromas and 8 healthy control persons were exposed to acoustic neuroma extract. Indirect leukocyte migration agarose technique was applied for detection of leukocyte migration inhibition (LMI). The standard technique was additionally modified using a specific assay for release of human leukocyte migration inhibitory factor (LIF). Both the standard technique and the LIF-specific assay revealed a significant LMI exerted by lymphocytes from patients, as compared with control persons. The LIF-specific assay demonstrates that the LMI is an expression of cell-mediated immunity due to release of LIF. The immune reaction is raised against an unknown antigen in acoustic neuroma extract. Further studies must determine whether the immune reaction is specific for acoustic neuroma patients vis-a-vis patients with other tumours, especially other neuromas.

Adult↗
PubMedDate not supplied

Experiments with a thinfilm multichannel electrode for cochlear implantation.

A series of experiments with a thinfilm multichannel cochlear implant is presented. A number of surgical difficulties at implantation on temporal bones were experienced. In vitro measurements of the electrode's technical properties revealed 1) large variations in the impedance, and 2) good separation between channels. From a theoretical point of view this complicated type of electrode is interesting, but a number of modifications are necessary before it may be used for implantation in man.

Biomedical Engineering↗
PubMedDate not supplied

Mastoid pneumatization in secretory otitis. Further support for the environmental theory.

A cohort of 222 randomized healthy children was followed with 7 repetitive tympanometries from the age of 4 to the age of 7 years. At the age of 8, the size of the mastoid air cell system in 17 children with normal tympanometric profiles and in 27 children with pathological tympanometric profiles, indicating secretory otitis, was examined by planimetry. The air cell system was significantly larger in the normal group than in the abnormal group, strongly indicating the validity of the environmental theory of pneumatization.

Acoustic Impedance Tests↗
PubMedDate not supplied

Mucus production in chronic maxillary sinusitis. A quantitative histopathological study.

A quantitative histological investigation, comprising 47 maxillary sinuses with chronic sinusitis subjected to the whole-mount method, was undertaken principally to determine the degree of mucus production. The goblet cell density in the maxillary sinus was found to be significantly lower (7350 cells/mm2) in chronic sinusitis than in the normal maxillary sinus (9700 cells/mm2). The gland density was 1.2 gland/mm2, which is six times that of the normal maxillary sinus. Several varieties of pathological tubulous glands were encountered; they could be simple and short, long, or branched. These glands are formed during the disease state as a result of basal cell hyperplasia. In addition to new formation of glands, the mucosa in chronic sinusitis also displayed hyperplasia and hyperactivity of the normal tubuloacinous, seromucous glands. It is concluded that the increased mucus production in chronic sinusitis mainly is derived from the newly formed glands.

Adolescent↗
PubMedDate not supplied

Antigenicity and protein content of perilymph in acoustic neuroma patients.

11 acoustic neuroma patients, exhibiting cell-mediated immunity in vitro against acoustic neuroma extract, were tested for cell-mediated immunity in vitro against perilymph samples from other acoustic neuroma patients. 14 of 21 perilymph samples were antigenic. None of three healthy persons reacted against antigenic perilymph samples. The perilymph antigenicity was reproducible and negatively correlated to the perilymph sample volume. Differences in sample volume could not be ascribed to admixture of endolymph, cerebrospinal fluid, plasma or blood. The perilymph protein concentration varied from 31 to 54 g/l. Gel electrophoresis of perilymph proteins revealed less staining in the alpha-region compared to plasma proteins and a distinct band in the pre-gamma region absent in plasma. Tau-transferrin was not detected in any of 13 samples. The findings support that the cell-mediated immune response against acoustic neuroma extract may be mediated through release of antigen(s) to the perilymph.

Adolescent↗
PubMedDate not supplied

Experimental long-term tubal occlusion in cats. A quantitative histopathological study.

Unilateral tubal occlusion was performed in 10 cats, which were sacrificed 26-44 months later. During the observation period repeated bilateral tympanometry and auditory nerve response were recorded. Paracentesis with evacuation of effusion was performed up to eight times and the effusion was examined by viscometry. After sacrifice, quantitative histopathology of the bulla with determination of goblet cell density was carried out. In three ears having glue at the last paracentesis, the histopathologic changes were more pronounced than in the four ears having thin effusion. Three ears were dry at sacrifice with normal tympanometry, the histopathological changes evidently demonstrate the the normalization of the middle ear mucosa. The experiments demonstrate the great importance of tubal patency or function in prognosis of the disease. In ears with anatomically occluded tubes, no recovery occurred, whereas in ears with normalized tubal function, the middle ear mucosa and goblet cell density also normalized. Pathogenic and etiological aspects of secretory otitis are discussed.

Acoustic Impedance Tests↗
PubMedDate not supplied

Pre- and postoperative facial nerve testing in patients with acoustic neuromas.

Clinical and electrophysiological examination of the facial nerve was performed in 49 consecutive patients, from December 1982 to January 1984, before and after surgical removal of acoustic neuroma. The electrophysiological examination included quantitative electromyography of the facial muscles and facial nerve stimulation with registration of amplitude and latency of evoked muscle potentials. 17 patients had tumours with an extrameatal size of 5-25 mm, 16 had tumours between 26 and 40 mm, and 16 (32%) tumours larger than 40 mm. At preoperative clinical examination, 9 patients had decreased facial motor function; 7 however, only by meticulous inspection, while 2 had a slight paresis. Two patients had hemifacial spasms. 25 patients had prolonged duration of motor unit potentials and/or increased incidence of polyphasic potentials by electromyography. Only one patient had denervation activity. Three patients had decreased amplitude of evoked muscle potentials to supramaximal stimulation of the facial nerve. Motor latency was normal. At the most recent examination between 3 and 12 months postoperatively, 65% of the patients had no or insignificant facial nerve involvement, 10% had slight and 25% significant involvement, of whom 6 had paralysis or only slight reinnervation. The preoperative clinical facial involvement and the degree of electrophysiological abnormality was poorly correlated to the motor function at the time of the most recent examination.

Adolescent↗
PubMedDate not supplied

The causes of asymmetry of the mastoid air cell system.

Starting from age 2 up to 7 years, 79 otherwise healthy children underwent nine tympanometric tests. At the age of 7, mastoid X-rays were obtained and the air cell areas measured by planimetry. The mean area was 8.4 cm2, with a left-right mean difference of 1.57 cm2. The children could be divided into three groups: (1) the ears with the smallest cell system associated with abnormal tympanograms (i.e. 'agreement'); (2) the ears with the largest cell system associated with abnormal tympanograms (i.e. 'disagreement'); (3) children with symmetrical cell systems and tympanograms. Significant majority of children showed 'agreement'. The results indicate that the size of the mastoid air cell system is determined by the degree of pathological involvement of the middle ear during childhood.

Acoustic Impedance Tests↗
PubMedDate not supplied

Nasopharyngeal bacteriology and secretory otitis media in young children.

A prevalence study was performed on the nasopharyngeal bacteriology of 112 young children, aged 4-6 years. During the preceding 2 years, 74 of these children had suffered from secretory otitis media (SOM) and 40 had had normal middle ear ventilation. At the examination, one-third of the children with SOM had improved their middle ear status (previous SOM group), whereas otomicroscopy and tympanometry remained unchanged in the healthy group. The nasopharyngeal swab sample was obtained from behind the soft palate by the oral route. The isolation rate of Streptococcus pneumoniae was significantly higher in the SOM group than in the two other groups of children (p less than 0.006). The most commonly isolated capsular types of pneumococci were 6, 19, and 23, corresponding to the types involved in acute otitis media. The isolation rate of Haemophilus influenzae was 50% and an even distribution was found among the three groups of children examined. Biotypes I, II, III and IV accounted for 75% of the isolated cases of H. influenzae. As in acute otitis media, S. pneumoniae also seemed to play an important role in the pathogenesis of tubal dysfunction and SOM, and the difference is probably caused by variations in the quantitative colonization of pneumococci in the nasopharynx.

Child, Preschool↗