SUMMARYWe have investigated a possible association beiween recurrence of otitis media and low concentrations of mannan-binding protein (MBP) in plasma and upper-airway secretions. The protein eoncentration was measured in plasma (H = 76). nasopharyngeal secretions (/j = 83) and middle ear effusions (« -73) from otitis-prone children, children wilh less recurrence of acule otitis media, children with no previous history of acute olitis media, but suffering from seeretory otitis media, and healthy children. Moreover, genetic polymorphistrts associated with low MBP plasma levels were investigated in DNA from nasopharyngeal tonsils of S9 children with recurrence of otitis media. A wide rangeof MBP plasma concentrations was found. No statistically significant differences in MBP plasma concetitralion were observed between patients and controls. Nor was there any increased frequency of the genotypes associated with low MBP plasma concentrations. Thus, our resulls do nol support the assumption thai low eoncenlration and/or MBP deficiency alone predispose to recurrence of otitis media in Caucasian children. MBP was detecicd in bolh nasopharyngeal secretions (1/175 of plasma level) and middleear effusions (1/4 of plasma level), suggesting a role for the protein in the local mucosal immune defence system at these locations. In contrast, MBP was undetectable in 53 samples of mixed-saliva.

in neonates receiving continuous intravenous infusion of gentamicin. APMIS 100: 1 19-124, 1992. Urinary excretion of the tubular enzymes NAG and AAP was investigated during gentamicin treatment of 105 newborn infants. The values found for NAG and AAP show a significant positive correlation. The urinary excretion of NAG was on the average 92% higher during gentamicin treatment as compared with non-treatment periods in the same newborn infant (33 infants). The same tendency applied to AAP. Newborn infants receiving continuous intravenous infusion of gentamicin were not found to be at greater risk of nephrotoxicity than those receiving intermittent gentamicin treatment, using NAG and AAP as an index of nephrotoxicity. The changes in NAG and AAP within treatment periods were studied. During gentamicin treatment an insignificant average increase in the urinary excretion of NAG occurred, whereas a significant decrease was found during non-treatment periods. A significant negative correlation was found between urinary excretion of NAG and birth weight / gestational age. The long-term effect of the higher excretion of NAG and AAP in newborn and adult patients during aminoglycoside treatment is unknown.

Moraxella (Branhaomella) catarrhalis is frequently present in the nasopharyngeal microflora of small children, especially during episodes of acute otitis media . By means of ribotyping (restriction endonuclease analysis of chromosomal DNA combined with rRNA probing), we studied the genetic heterogeneity of 78 cultures of M. catarrhalis obtained from different localities in the nasopharynx of nine young children with secretory otitis media. Using HindIII and PstI as endonucleases, five different ribotypes were recognized, representing at least five different genotypes of M. catarrhalis. The distribution of these types was found to be almost identical to the distribution among 16 M. catarrhalis strains cultured from middle ear exudates of 16 children with acute otitis media. Ribotype HAPA was found in two-thirds of all the cultures investigated, and 44% of the children harboured more than one ribotype in the nasopharynx at the same time. The vast majority of the nasopharyngeal M. catarrhalis cultures were beta-lactamase positive. One child had both a HAPA ribotype, beta-lactamase-negative strain in the nasopharyngeal secretions, and HAPA ribotype, beta-lactamase-positive strains at the entrance of the eustachian tube, the nasopharyngeal tonsils, the folds of the nasopharyngeal tonsils and the oropharynx. All except one of the M. catarrhalis strains cultured from middle ear exudates were beta-lactamase positive.

The pathogenesis of otitis media is a multifaceted process that is not completely understood. Eustachian tube dysfunction plays a central but uncertain role, as do viral and bacterial microorganisms. Of the latter, the three most important are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. This article reviews the various mechanisms of infection and the immune system's response to them.