A. Melagrana

Heterogeneity of Tonsillar Subepithelial B Lymphocytes, the Splenic Marginal Zone Equivalents

The VH4 genes expressed by both resting and in vivo-activated subepithelial (SE) B cells from human tonsils were studied. Resting SE B cells were subdivided according to the presence (IgDlow) or absence (IgM-only) of surface IgD. CD27 was abundant on activated SE B cells and low on resting IgM-only B cells. Resting IgDlow SE B cells could be subdivided into CD27low and CD27high cell fractions. Resting IgDlow SE B cells displayed VH4 genes with a substantial number of mutations (13/29 of the molecular clones were mutated), whereas 25/26 of the clones from resting IgM-only SE B cells were unmutated. Moreover, mutated VH4 genes were detected mainly within the CD27high cell fraction of the IgDlow SE B cells. Several identical unmutated VH4DJH sequences (11/32) were found in different molecular clones from resting IgM-only SE B cells, suggesting local cellular expansion. Both unmutated (14/25) and mutated (11/25) sequences were found in μ transcripts of activated SE B cells. Extensive mutation was observed in the γ transcripts of activated SE B cells. Therefore, SE B cells are heterogeneous, being comprised of B cells with mutated Ig VH4 genes, that are Ag-experienced B cells, and a subset of B cells with unmutated VH4 genes that are either virgin cells or cells driven by Ags that did not induce or select for V gene mutations.

Acute mastoiditis: a 10 year retrospective study

This retrospective study reviews our experience in the management of acute otomastoiditis over 10 years. During the study period we identified 40 cases in children aged 3 months-15 years with a peak incidence in the second year of life. Sixty per cent of them had a history of acute otitis media (AOM). All the children were already receiving oral antibiotic therapy. Otalgia, fever, poor feeding and vomiting were the most common symptoms, all the children had evidence of retroauricolar inflammation. Computerized tomography (CT) and magnetic resonance imaging (MRI) were used to support the diagnosis and to evaluate possible complications. Streptococcus pneumoniae was the most common isolated bacterium. All the patients received intravenous antibiotics, 65% of children received only medical treatment, 35% also underwent surgical intervention. Mean length of hospital stay was 12.3 days. Cholesteathoma was diagnosed in one child. We conclude from our study that acute otomastoiditis is a disease mainly affecting young children, that develops from AOM resistant to oral antibiotics. Adequate initial management always requires intravenous antibiotics, conservative surgical treatment with miryngotomy is appropriate in children not responding within 48 h from beginning of therapy. Mastoidectomy should be performed in all the patients with acute coalescent mastoiditis or in case of evidence of intracranial complications.

Otoneurologic evaluation of child vertigo

In this study 282 children with vertigo are subdivided (according to previous experiences) into three large groups: (1) vertigo and cochlear diseases; (2) vertigo as an isolated symptom; and (3) vertigo and C.S.N. diseases. Due to the difficult etiopathogenetic investigation of the patients from the second group, the authors focused on that group as they are less studied, are without associated symptoms (deafness--first group; CNS diseases--second group) and where vertigo appears as an idiopathic and an isolated symptom. A careful anamnestic, clinical and instrumental analysis leads to the following observations: (1) in decreasing order of frequency we find the third group, followed by the first and finally by the second; (2) in spite of the overall lower incidence of the second group, this latter includes the paroxismal benign vertigo (PBV) which is overall the second most frequent vertiginous form (after vertigo due to cranial trauma). In this group the authors underline the reasonably high incidence of the iatrogenic syndromes, insisting on the need of their accurate prevention of these risks; (3) the authors confirm that, nowadays, a reliable etiopathogenetic cause of the apparently isolated vertigo (except for the ascertained iatrogenic forms) cannot be identified. Moreover, in spite of its frequency, PBV is the less known form of vertigo, of which we cannot give a certain diagnosis and which can be identified only the the exclusion of all the other known forms through instrumental and clinical observations.

Benign positional paroxysmal vertigo of horizontal semicircular canal in the child: case report

The authors report on a 10-year-old with benign positional paroxysmal vertigo (BPPV) of the horizontal semicircular canal (HSC). To date, no case of BPPV of HSC in the child has been reported in the literature. The authors define the features of the disease, describe its evolution, and compare it with the other vestibular diseases affecting children.

In vitro stimulation of human tonsillar subepithelial B cells: Requirement for interaction with activated T cells

Human tonsillar subepithelial B cells, which are a marginal zone‐equivalent B cell subset, respond readily to T‐independent type 2 antigens, but not to polyclonal B cell activators in vitro. In this study, subepithelial (SE) B cells were induced to proliferate and mature into plasma cells when co‐cultured with activated T cells. The response of SE B cells was not observed when co‐cultures were carried out in transwell chambers or in the presence of blocking anti‐LFA‐1 antibodies, demonstrating the need for a close T‐B cell interaction. The presence of soluble CD40 also prevented the B cell response in vitro suggesting a pivotal role of CD40‐CD40 ligand interactions. The data are discussed in terms of the T cell dependence of marginal zone (MZ) B cell response and the possible existence of various MZ B cell subsets.

Electronystagmography findings in child unilateral sensorineural hearing loss of probable viral origin.

We studied the labyrinthine function in a group of 72 children aged between 4 and 14 years affected by unilateral sensorineural hearing loss of probable viral origin. From the analysis of the results obtained we confirm the concomitance of cochlear and vestibular damage. However, there were no statistically significant differences between type of audiogram at onset of hearing loss and type of electronystagmography (ENG), while we found a direct correlation between the presence of vertigo or dizziness and type of ENG. Finally hearing recovery was influenced by the presence of vertigo or labyrinthine function alterations. The results of statistical analysis confirmed a significant statistical difference between patients with vertigo or dizziness (V(+)) and those without vertigo (V(-)) and also between patients with ENG 3 (subjects with spontaneous nystagmus or positional nystagmus and canal paresis ipsilateral to the cochlear lesion) and those with ENG 1 (subjects without spontaneous nystagmus or positional nystagmus and with normal vestibular reflex). In fact, hearing recovery was worse in V(+) group and in ENG 3 group.

Study of labyrinthine function in children using the caloric test: our results

We studied caloric responses in a group of 42 healthy children aged between 4 and 14 years and compared the results with those obtained with the same method and equipment in a control group of 57 healthy adults at the Methodist Hospital Electronystagmography Laboratory at Houston (Texas). The average response in children appeared to be rather low. The confidence regions for unilateral weakness (UW) and directional preponderance (DP) measures were much wider in children than in adults. The confidence limit for bilateral weakness (BW) was lower in the children. The confidence limit for the fixation index (FI) in the children, however, was close to that in adults.

Comparison between air and water caloric tests in children

The caloric test represents an essential part of each procedure evaluating vestibular function. The use of water has many contraindications: tympanic perforation, external otitis and mastoid diseases. Sometimes, nausea can make test execution very difficult. Several authors contributed to the study and diffusion of the caloric test for the evaluation of labyrinthine function using different types of otoalcorimeters. We compared two methods in the child--generally intolerant to the water test--and the results obtained were adapted to a mathematical model of air and water caloric nystagmus. Twenty-seven normal children, aged between 5 and 14 years, subdivided into three age groups (5-7, 8-10 and 11-14 years), underwent the water caloric test (250 cm3 at 31 and 43 degrees C for 40 s) and then the air test, together with another nine subjects undergoing only the air test (flow-rate 8 l/min at 25 and 49 degrees C) on different days. The comparison between the two stimulation methods showed a statistically significant difference (P < 0.002) between maximum slow speed component (max SSC) in degrees per second (degrees/s) of water (4.74 degrees/s) and air (2.98 degrees/s). The results of two caloric tests and the interindividual and intraindividual analysis of our electronystagmographic results are in agreement with the data obtained by other authors in studies on adults. Therefore, notwithstanding the differences between the two stimulation methods, the air caloric test can be applied in a larger number of cases, it is better tolerated and can thus be used even in children for the study of labyrinthine function.

The study of optokinetic 'look' nystagmus in children: our experience.

Seventy health children underwent an OKN trial. The authors have chosen to perform only four tests (slow and fast clockwise and counterclockwise OKN) taking into account (in agreement with several international studies) four parameters: sTAP, fTAP, sTSAP, fTSAP (where s and f indicate the velocity of the shifting target slow or fast, TAP is total asymmetry percentage of the SSC--speed of slow components--and TSAP is total asymmetry percentage of saccades). They carried out the statistical analysis of the results, which did not show peculiar difference between child and adult OKN. The result of the test was independent of the side first tested and of sex. The authors have tried to identify the normal range of values more suitable to the study of child OKN; on the basis of the calculation of the 95% percentile the normality range was wider than the range assumed for adults. The authors have also tried to subdivided the results for three different groups of age (I = 3-7 years; II = 8-11 years; III = 12-14 years) in order to observe the degree of OKN maturation with age. From the results obtained the maturation of OKN pathways seems to occur in the 7th year of age for the slow movements; the findings related to the fast movements are more doubtful and need further analysis. Finally, although the number of saccades interposed to the tracings depends on enormous variations unrelated to age, sex and first side tested, our data show their higher incidence during the slow test.

The air caloric test in children: subdivision and statistical analysis of the response

Among a population of 200 children, suffering by dizziness that we examined in the ENT department of the G. Gaslini Institute of Genoa, we acquired and checked, through the statistical analysis, the data of an air caloric test (according to the standard stimulation method) performed in 20 children (resulted normal to neurological, ophtalmological and audiovestibuler examinations which included audiometry, tympanometry, spontaneous, positional and positioning nystagmus research, OKN and caloric tests) and subdivided into 10 s sequences. The statistical analysis of the results obtained showed the following: (1) in both cold and warm air caloric test, the response can be obtained already in the stimulation phase, requiring ENG recording to start at the beginning of stimulation; (2) even in children, response culmination occurs in a period ranging from 60 to 90 s from stimulation onset; therefore the Visual Suppression Test should be performed in this period to obtain more significant data; (3) in cold and warm test, considering SSCs, the response is constant and intense up to 130 and 110 s, respectively, from beginning of ENG recording. After these time ranges, the response is less intense and homogeneous, becoming poor and variable. In our opinion, this allows suspension of recording immediately after these periods without the risk of the excluding significant aspects of the response.