Acquired cholesteatoma in children: Strategies and medium-term results

SummaryObjectivesTo assess paediatric cholesteatoma surgical management strategies, residual disease and recurrence rates and especially the medium-term auditory impact.Material and methodsRetrospective study of 22 cases of acquired middle ear cholesteatoma selected from a series of 77 children under the age of 16 operated for cholesteatoma between 1st January 2000 and 31st December 2003 on the basis of the following criteria: first-line surgical management with postoperative follow-up greater than four years. Surgical strategies, preoperative and postoperative (at 1 year and at the final visit) audiograms and residual disease and recurrence rates were analysed.ResultsA canal wall up tympanoplasty was performed in 82% of cases as first-line procedure and a canal wall down tympanoplasty was performed in 32% of cases. Residual cholesteatoma was observed in 9% of cases and recurrent disease was observed in 18% of cases. The mean preoperative hearing loss was 26dB with an air-bone gap of 23dB with values of 26dB and 20dB respectively at the end of follow-up.ConclusionThe majority of children were operated by two-stage canal wall up tympanoplasty. Long-term hearing results remained stable and close to preoperative values. The recurrence rate (residual disease and relapse) was low (27%), as reported in the literature

[The environment of tRNA 3'-terminus in 80S ribosome A and P sites]

International audienceThe environment of tRNA 3'-terminus in the 80S ribosomal A and P sites was studied with a tRNA(Asp) analogue that bears a 4-thiouridine residue (s4U) attached to the 3'-terminal adenosine. The tRNA(Asp) analogue was obtained by in vitro T7 transcription followed by crosslinking with [32P]ps4Up and removal of the 3'-terminal phosphate. It was shown that the presence of the additional nucleotide at the 3'-end does not to hinder the codon-dependent binding of the tRNA to the A and P sites of 80S ribosome. Mild UV-irradiation of the ribosomal complexes containing a short appropriately designed mRNA and the tRNA analogue resulted in crosslinking of the analogue exclusively to 28S rRNA. The crosslinking was completely dependent on the presence of s4U in the tRNA analogue. Using hydrolysis of the crosslinked 28S rRNA with RNase H in the presence of deoxyoligomers complementary to various rRNA sequences, we determined that the crosslinking occurred in fragment 4302-4540 of the 28S rRNA. This fragment is evolutionarily conservative and belongs to domain V that is involved in the formation of the peptidyl transferase site in prokaryotic ribosomes. The use of reverse transcription allowed the determination of the tRNA analogue crosslinking in the P site to nucleotides U4461 and U4502, and the analogue in the A site, to nucleotides U4469 and C4507. In addition, nucleotide C4462 was crosslinked to both P site and A site-bound tRNA analogue. An analysis of the results demonstrates that environments of the tRNA 3'-termini are closely similar in both prokaryotic and eukaryotic ribosomes