No abstract

To evaluate possible risk factors for developing recurrent acute otitis media (rAOM), 113 children were followed prospectively from birth to the age of 3 years. One of the aims was to determine whether such risk factors could be identified before the onset of the recurrences, so that optimal care and prophylactic measures could be made available at an early stage in such cases, on the basis of continuous follow-up by an ENT specialist. During the follow-up, 13 children developed rAOM, defined as six or more episodes of acute otitis media (AOM) during a 12-month period, 57 children had occasional episodes of AOM, and 43 children had no AOM at all. Of the children with onset of AOM before 6 months of age, 80% developed frequent episodes of AOM. The frequency of other respiratory tract infections and of family histories of otitis-proneness was higher among rAOM children than among the other children. The development of rAOM was unrelated to such factors as sex, familial history of allergy, duration of breast-feeding, or domestic environment. Nor could attendance at day-care centres be concluded as constituting a risk factor for the development of rAOM. An onset of AOM before 6 months of age was highly predictive of subsequent recurrent bouts of AOM, which emphasizes the importance of correct diagnosis in infants.

No abstract

Monoclonal antibodies and flow cytometry are now used routinely in the diagnosis of many malignant diseases and primary and secondary immunodeficiency states. Technical advances have improved the identification of blood lymphocyte subsets and reliable normal values are now obtainable. Such values have been reported for adults but not for children. We report both absolute and percentage normal values for lymphocytes and their subsets in infants and children of different ages. Our findings show that the absolute and percentage values for most lymphocyte markers differ substantially not only between children and adults, but also between children from different age groups. In infants, erythroid cell contamination of Ficoll gradient-density isolated mononuclear cells must be removed to obtain reliable flow cytometry values.

Middle ears of male Sprague-Dawley rats were injected with suspensions of thirteen Haemophilus influenzae strains of different sero- and biotypes and at various concentrations. Systemic and local changes were monitored by clinical observations, otomicroscopy, and analysis of bacterial samples from blood and middle ears. Two patterns of response were recognized, a nontypeable and an encapsulated pattern. The nontypeable H. influenzae middle ear infection required a high bacterial dose and was well past its peak 8 days after challenge, when the encapsulated H. influenzae otitis media was still purulent. The most severe infections were caused by H. influenzae type b strains. The overall mortality rate was zero and the animals recovered without permanent deterioration or otomicroscopically discernable changes. The results of this study show the rat to be a suitable animal model for the study of H. influenzae otitis media.

No abstract

We examined the mucosa of 50 rat middle ears in an experimental model of acute otitis media, in order to obtain information on the mechanisms of polyp formation. The right middle ear of 25 rats was inoculated with type 3 pneumococci, and the left ear served as a control. The animals were killed, the middle ear bulla removed, and the mucosa was dissected from the bone, stained PAS-alcian blue and embedded as a whole-mount. The whole-mounts were examined in a light microscope for polypous mucosal prominences. Serial sections were made of all polyps, and of relevant parts of the mucosa. 15 polyps were found in 11 (44%) of 25 infected ears; none were found in normal control ears. Goblet cell density was increased in polyps and the surrounding epithelium. Epithelial microruptures were seen in areas with widespread intra-epithelial liquid vacuoles and subepithelial accumulation of liquids, luminally migrating inflammatory cells, increased vascularization and edema. Connective tissue of the lamina propria was prolapsed through most ruptures. Some prolapses showed signs of re-epithelialization, while others had a full epithelial lining that resembled a fully developed polyp. Our findings support our earlier theory on nasal polyp pathogenesis, based on the following stages: i) Localized rupture of the epithelial lining. ii) Luminal protrusion of the lamina propria through the epithelial defect. iii) Re-epithelialization of protruded tissue, and formation of a polyp.(ABSTRACT TRUNCATED AT 250 WORDS)

A long-term study of nasopharyngeal carriership in 405 children, aged 6 months to 5 years, attending day-care centres was performed. The effect of pneumococcal vaccination was evaluated in a double-blind investigation where the children received either Pneumovax (a 14-valent pneumococcal vaccine) or saline. Nasopharyngeal cultures were taken monthly by a trained nurse during a 2-year follow-up period. No difference in pneumococcal carriage was found between vaccinees and controls. Pneumococci were found in 31.9% of all cultures. In day-care centres attended by greater than or equal to 45 children the carriage rate of pneumococci was significantly higher than in centres with less than 45 children. Spreading of pneumococci within day-care centres was common but rather short-lived. Children younger than 2 years showed the highest carriage rates. Pneumococci of group 6 were carried most frequently and for longer periods than groups 19 and 23.