Incidence of congenital CMV in children at a hearing rehabilitation center.

OBJECTIVE: To evaluate the incidence of children with congenital CMV (cCMV) infection in a hearing rehabilitation center. METHODOLOGY: This was a retrospective review of 309 children followed in a rehabilitation center for mild to total sensorineural hearing loss (SNHL). Seventy-five children had dried blood spots that we retrieved and retrospectively analyzed for the presence of CMV DNA by real time PCR. The children were born in Belgium after January 1996. The etiology of the SNHL was investigated for each child. RESULTS: The CMV DNA was detected in the dried blood spots for 8 of the 75 children tested (10.6%) by real time PCR. In three children, an alternative etiology of SNHL was suspected before the cCMV infection was diagnosed. CONCLUSIONS: The incidence of children infected with cCMV in a hearing rehabilitation center is high (10.6%). The detection of CMV DNA in dried blood spots is useful and improves the etiological diagnosis of SNHL.

[Hearing screening of newborns. Preliminary results]. / Le dépistage auditif des nouveau-nés. Résultats préliminaires.

Since 1976, an hearing screening is organized at the Clinic Edith Cavell. The testing was based on a behavioral technique of Veit-Bizaguet and, since 2001, the otoacoustic emissions are realised. The National Institutes of Health (1993) recommends universal newborn hearing screening of all newborns before 3 months of age and identification and treatment before 6 months of age. Indeed, detection of hearing loss and early intervention allow a better access to the language and consequently an easier schooling and social integration. This article shows the results of the screening from february at the end of December 2002. These data are compared with those of the literature.

Experimental optimization of the detection limit of one-step solid-phase radioimmunoassay.

The minimal detection limit and the conditions of maximal sensitivity of a one-step solid-phase inhibition radioimmunoassay for human immunoglobulin A have been determined by application of statistical methods of experimental optimization. The choice of the optimal combination of qualitative variables, such as the origin of the antibody and the nature of the solid phase, was made by the study of a covariable under non-optimal conditions of the quantitative variables, such as the amount of antibody. The covariable was the avidity of the antibody, which is expected to have a large influence on the sensitivity. Only the difference in avidity between two immunosorbents with cellulose or Sepharose as solid-phase material proved to be statistically significant, and further study was done with cellulose. The experimental optimization of the sensitivity as a function of five quantitative variables yielded a reduction of the detection limit by a factor 5.6 (from 23.5 to 4.2 ng IgA). The variables determining the amount of insolubilized antibody in the assay had the largest influence on the value of the detection limit. The conditions of optimal sensitivity did agree with the predictions by a physical model of radioimmunoassay. The results are discussed in relation to the assay parameters such as the amount and the avidity of the insolubilized antibody and the initial percentage of binding, and in relation with theoretical optimization of the sensitivity.

Experimental optimization of the detection limit of two-step solid-phase radioimmunoassay.

For two-step inhibition radioimmunoassay (sequential saturation or delayed addition of labeled antigen) generally a higher sensitivity than for one-step inhibition radioimmunoassay (equilibrium assay) is expected. The detection limit of a two-step solid phase inhibition radioimmunoassay for human serum immunoglobulin A was minimized by statistical methods of experimental optimization. Under optimal conditions the detection limit was 2.3 ng IgA. This is about 1.8 times lower than the minimal detection limit of the one-step assay under similar conditions of the qualitative variables such as the origin of the antibody. This increase in sensitivity was associated with a decrease in the precision of the assay. The results are discussed with respect to the comparison of the one-step and the two-step assay and the usefulness of a sensitive radioimmunoassay in practice.

Investigation of two new [99mTc]Tc-HEDP preparations that can be expected to give a better lesion-to-normal-bone uptake ratio when used as bone scanning agents.

Two new potential bone scanning agents have been prepared and characterized. One of the agents, Tc(Sn,pH 12)-HEDP, is prepared at pH 12 (and subsequently neutralized). The other agent, Tc(Fe)-HEDP, is prepared by reducing [99mTc]TcO4- by a mixture of Fe(II) and Sn(II). From ion exchange chromatography on Aminex A-28 it appeared that the proportion of early eluting components of the two new agents is larger than that of the usual agent, Tc(Sn,pH 7.4)-HEDP. The stabilities on storage, and in serum, of the three agents appeared to be equally good. The adsorption on tri-calciumphosphate of Tc(Fe)-HEDP and Tc(Sn,pH 7.4)-HEDP was determined at several values of concentrations of Sn(II) and HEDP. Further, the influence of the pH (1-12) during reduction of [99mTc]TcO4- by Sn(II) on the adsorption of the agent on tri-calciumphosphate (at a fixed pH of 7.4) was investigated. It appeared that the adsorption of Tc(Sn,pH 12)-HEDP and Tc(Fe)-HEDP is less than that of Tc(Sn,pH 7.4)-HEDP. It is argued that this result points to a better efficiency in lesion detection of the two new agents, compared to the usual one.

Infective endocarditis on mitral valve prolapse (IEMVP): report of one case due to H. paraphrophilus and discussion of IEMVP with emphasis on its prophylaxis.

We describe one case of infective endocarditis on mitral valve prolapse (IEMVP) due to H. paraphrophilus and briefly discuss this pathogen and the valvulopathy. We than enhance some notions on IEMVP and especially on its controversial prophylaxis.

[Sensitivity and specificity of blood amylase, amylase and creatinine clearance ratio and urinary amylase/urinary creatinine ratio in the diagnosis of acute pancreatitis]. / Sensibilité et spécificité de l'amylasémie, du rapport des clairances d'amylase et de créatinine et du rapport amylasurie/créatininurie pour le diagnostic des pancréatites aiguës.

The sensitivity and specificity of amylasemia, the ratios of amylase/creatinine clearance and amylasuria/creatininuria were determined in four groups of patients: a control group (n = 43), patients with acute pancreatitis detected on computed tomography (n = 30, 25 cases of alcoholic pancreatitis), patients with an acute surgical abdomen without pancreatitis (n = 25), and patients with renal failure (n = 20). Sensitivity was defined for the acute pancreatitis group and specificity for the other groups. When amylasemia was greater than 20 UI/dl and the amylasuria/creatininuria ratio greater than 100, sensitivity was 98 per cent. The specificity of these two results in patients with an acute surgical abdomen was 98 per cent. When the ratio amylase/creatinine clearance ratio was greater than 4 sensitivity was 73 per cent and specificity in patients with acute surgical abdomen was 75 per cent. These two values were lower than those of the two preceding tests (p less than 0.01). Sensitivity of the association of an amylasemia greater than 13 UI/dl (m + 2SD) with a clearance ratio greater than 4 was 73 per cent. The amylase/creatinine clearance ratio did not seem to be reliable since its change was delayed with respect to the increase of amylasemia and amylasuria. This ratio has a poor specificity as it increased when the clearance of creatinine decreased in the group with an acute surgical abdomen associated with functional or organic renal failure. In these two groups, the correlation between the amylase/creatinine clearance ratio and creatininemia was significant. This suggested that the clearance of creatinine fell more rapidly than the clearance of amylase as renal failure increased.

[Asthma: psychosomatic disease in children and adults (scientific and literary review of the literature)]. / L'asthme: maladie psychosomatique de l'enfant et de l'adulte (revue de littérature scientifique et littéraire).

The personality of the asthmatic child, and his relation with his mother-characterized by an absence of normal separation and individuation-is examined through scientific and literary sources. The familial milieu and various behavioral attitudes of the asthmatic patient are also considered. Various therapeutic approaches are discussed.

[Cochlear implantation, new prosthetic alternative in the management of the profoundly deaf child]. / L'implant cochléaire, nouvelle alternative prothétique dans la prise en charge de l'enfant sourd profond.

Cochlear implants are new medical devices. In contrast to acoustic hearing aids which work by amplification, cochlear implants directly stimulate the hearing neurons via electrode implanted in the cochlear tympanic ramp. They are indicated in case of profound hearing deficiency or in cases of bilateral cophosis, congenital or acquired. Implanted early, they allow deaf children to improve their speech comprehension and their verbal expression considerably, thereby favouring social integration. A concurrent system of support including the use of visual-manual means of communication nevertheless remains vital for the first years. The frequency and duration of such support varies according to the individual.

Clinical findings and PDS mutations in 15 patients with hearing loss and dilatation of the vestibular aqueduct.

Following systematic skull imaging of hundred and sixty seven individuals attending a medical referral centre for the deaf in Brussels, Belgium, fifteen patients (9 per cent) aged between two and 25 years were diagnosed with dilatation of the vestibular aqueduct. Careful audiological study, with a baseline assessment then longitudinal follow up, indicated mild to profound deafness with a progressive course (i.e. an average loss of 3.3 dB per year) and frequent dizziness. Sequencing of PDS was performed in all individuals. Alterations of this gene (either homozygous, heterozygous or compound heterozygous base changes) were found in 53 per cent of patients with a large vestibular aqueduct. Four new mutations (two missense, a splice site and a four base pair insertion) were described. We were unable to confirm a correlation between homozygosity, heterozygosity and a Pendred or deafness-only phenotype.

99mTc bone scanning agents--III. Preparation and gel chromatography of 99mTc(Sn)MDP complexes.

The preparation of 99mTc(Sn)MDP was investigated as a function of pH, MDP concentration and Sn(II) concentration. The labeling efficiency was over 90% in the majority of the experiments and remained constant over the range pH 2-9. The MDP concentration had little effect, while the Sn(II) concentration had a significant positive influence. The complex formation appeared to be partly reversible. The formation of different complexes was investigated by means of gel chromatography under various experimental conditions. Altogether six complexes were found. At acid conditions two major complexes were found and at neutral pH one major complex. The presence or absence of a particular complex was mainly determined by the pH and by the MDP concentration. The Sn(II) concentration had very little effect. The results are compared with previous results of similar experiments with 99mTc(Sn)pyrophosphate.

99mTc bone scanning agents--I. Influence of experimental conditions on the formation and gel chromatography of 99mTc(Sn)pyrophosphate complexes.

The conversion of 99mTcO4- to 99mTc(Sn)pyrophosphate complexes was investigated under various experimental conditions. An increase of the Sn(II) concentration had a beneficial effect, whereas the ligand concentration had little effect. The pH had only a small influence over the range 2-8. Raising the pH to 10 resulted in the partial decomposition of the complexes, which could be reversed by lowering the pH. Furthermore, the occurrence of various complexes was investigated by means of gel chromatography on Biogel P-4 as a function of pH and of the Sn(II) and pyrophosphate concentrations. Four major fractions were found. A single preparation contained, however, no more than two major fractions. The formation of the different complexes was mainly governed by the pH and the ligand concentration. The influence of the eluent on the decomposition and interconversion of the complexes during chromatography was also studied. It appeared to be necessary that the eluent should have the same composition (except for 99mTcO4-) as the reaction mixture.

Anion exchange chromatography of 99mTc(Sn)-MDP complexes: influence of eluent composition, determination of void volume and charge of the main component.

99mTc(Sn)-MDP complexes have been prepared by reduction of 99mTcO4- by Sn(II) in the presence of MDP. These complexes were separated on an anion exchange column. The necessity of the addition of the ligand and the reducing agent to the eluent to avoid decomposition during chromatography is demonstrated. For the main component that is found at pH 5 the ionic charge was calculated according to the method of Wilson and Pinkerton [Anal. Chem. 57,246 (1985)] and the method of Russell and Bishoff [Int. J. Appl. Radiat. Isot. 35,859 (1985)]. With the first method a charge of -4.2 +/- 0.3 was obtained, with the second a charge of -5.1 +/- 0.6. An accurate method to determine the void volume of the ion exchange column is described.

Effect of the composition of the eluent in the chromatography of 99mTc-diphosphonate complexes.

When the ligand and the reducing agent are added to the eluent used in the separation of 99mTc-diphosphonate complexes by column chromatography, a significant increase in recovery is obtained. The addition of the ligand and the reducing agent also influences the shape of the chromatogram.

99mTc bone scanning agents--IV. Chemical characterization of 99mTc(Sn)-pyrophosphate complexes.

Various reaction mixtures for the preparation of 99Tc(Sn)-pyrophosphate were investigated by means of gel chromatography. All components were radioactively labeled. The most likely composition of the complexes, which also appear in "no carrier added" preparations, was determined. At pH 7 one complex is found with the composition TcPyp2. Two complexes are found at pH 4: TcPyp and TcPyp2. Further, at pH 7 a polymeric technetium compound is found not containing tin or pyrophosphate.

99mTc bone scanning agents--II. Adsorption of 99mTc(Sn)pyrophosphate complexes on the mineral phase of bone.

The adsorption of pyrophosphate, tin-pyrophosphate and 99mTc(Sn)pyrophosphate on Ca3(PO4)2 was investigated at pH 4.0 and pH 7.4. All components were radioactively labeled. Tin and reduced technetium were in most cases almost completely bound. The adsorption of pyrophosphate, tin(II) and technetium-99m at pH 4.0 was higher than at pH 7.4. The presence of tin gave rise to an increase of the pyrophosphate adsorption that was much larger than can be accounted for by a stoichiometric adsorption of tin-pyrophosphate. It is concluded that tin and technetium are bound as negatively charged complexes with pyrophosphate. Finally it is argued that the fraction of the bone scanning agent that reaches the bone surface is adsorbed completely by the mineral phase.